WO2015001979A1

WO2015001979A1 - Method for producing substrate with coating film

Info

Publication number: WO2015001979A1
Application number: PCT/JP2014/066329
Authority: WO
Inventors: 雄一 ▲桑▼原
Original assignee: 旭硝子株式会社
Priority date: 2013-07-05
Filing date: 2014-06-19
Publication date: 2015-01-08
Also published as: JP2016163847A

Abstract

　Provided is a method for forming a coating film comprising an inorganic material on a substrate, wherein it is possible to efficiently thicken the coating film, and the development of film cracking or peeling is made difficult, even if the thickness of the coating film increases. A method for producing a substrate with a coating film, having a step for spraying a coating solution containing inorganic particles, alkoxysilane hydrolyzate, and a liquid medium on a substrate kept at 200-650°C, the average aggregate diameter of the inorganic particles being less than 100 nm and the liquid medium containing a polyvalent hydroxyl group-containing compound and/or water.

Description

Manufacturing method of substrate with coating film

The present invention relates to a method for producing a coated substrate.

A coating film (inorganic film) made of an inorganic material has an advantage of higher heat resistance and ultraviolet resistance than a coating film (organic film) made of an organic material. Therefore, if a thick (large) inorganic film can be formed on a substrate, it is useful as a binder for fixing particles that impart various optical characteristics, electrical characteristics, and chemical characteristics to the substrate. It is also possible to give the above properties to the inorganic film itself.

As a method for forming an inorganic film, a method of forming a coating film containing a film forming precursor on a substrate using a liquid containing a film forming precursor and then baking and solidifying the coating film is known. ing.
However, thermal shrinkage of the coating film is likely to occur during baking and solidification, thereby generating shrinkage stress. This shrinkage stress increases as the film thickness increases, causing cracks or film peeling. For this reason, a method that can suppress the occurrence of cracks or film peeling even when the film thickness increases is desired.

In Patent Document 1, an organic substance that gels by heating or cooling, such as methylcellulose or agar, is contained in a dispersion of silica glass particles, the dispersion is applied onto a substrate, and the coating is gelled and dried. Thereafter, a method of firing at a temperature equal to or higher than the glass transition point of the silica glass particles is described, and in the examples, it is described that a silica film having a film thickness of about 60 to 200 μm is formed. In the examples, it is described that a series of steps of coating, gelation and drying was repeated three times, followed by firing to form a silica film having a film thickness of about 0.3 to 0.6 mm.
However, this method requires processing at an extremely high temperature, so that the productivity is low and the types of substrates that can be used are limited.
In Patent Document 2, an organic-inorganic composite coating film is formed using a sol solution containing an organic molecular assembly and an inorganic precursor, and then the coating film is dried to remove moisture, followed by organic irradiation by ultraviolet irradiation. It describes a method of forming an inorganic film having nanopores with a film thickness of 1 μm or more while removing cracking or peeling by removing components.
However, since this method includes many steps for film formation, productivity is low.

As a method of forming an inorganic film free from cracks or film peeling, a method of spraying a liquid containing a film formation precursor onto a substrate heated to a firing temperature or higher is known. This method is different from the conventional method in which a coating film is formed on a substrate with a liquid containing a film-forming precursor and then fired and solidified, and the droplets sprayed on the substrate are immediately fired and solidified. The number is small and the productivity is good. Further, the solvent component and the organic component in the sprayed droplets are easily removed before the droplets reach the substrate. For this reason, the shrinkage stress which arises in a film | membrane is reduced significantly and generation | occurrence | production of a crack and film | membrane peeling is suppressed. Furthermore, even when the film thickness is increased by increasing the spraying time, the shrinkage stress is easily kept constant, and cracking or peeling is unlikely to occur.
For example, Patent Document 3 discloses that a film forming solution containing an organometallic compound and an organosilicon compound is sprayed onto a substrate heated to a temperature higher than the firing temperature, and a refractive index-reducing transparent coating comprising a silicon oxide thin film containing a metal oxide. A method of forming is described.
In Patent Document 4, a coating liquid containing an organopolysiloxane, inorganic particles, and a liquid medium is applied to a glass substrate in a temperature range of 400 to 650 ° C. by a spray method or the like to oxidize containing inorganic particles. A method of forming a silicon film is described.
Patent Document 5 describes a method for obtaining glass with an infrared shielding film by dispersing ITO fine particles in a hydrolyzate of tetramethoxysilane using ethanol or 2-propanol, and baking after applying by spin coating or the like. Has been.
Further, in Patent Document 6, ethanol or 2-propanol is used, and metal oxide fine particles such as tin oxide and titania are dispersed in a hydrolyzate of tetramethoxysilane. A method for obtaining a glass of is described.

Japanese Unexamined Patent Publication No. 2013-035723 Japanese Unexamined Patent Publication No. 2006-130889 Japanese Unexamined Patent Publication No. 07-097237 International Publication No. 2011/155545 Japanese Unexamined Patent Publication No. 2005-194169 Japanese Unexamined Patent Publication No. 2013-136696

The method described in Patent Document 3 does not contain inorganic particles in the film forming solution, and the film deposition efficiency expressed by the film thickness of the formed film per unit volume of the spray amount of the coating liquid is inferior, It is difficult to efficiently thicken the coating film.
In the method described in Patent Document 4, since the organopolysiloxane is nonpolar, the liquid medium of the coating liquid is limited to a nonpolar one, and the inorganic particles can be dispersed in the nonpolar liquid medium or previously hydrophobized. Limited to processed.
The methods described in Patent Documents 5 and 6 have a problem that cracks are likely to occur when the film thickness increases.

The present invention has been made in view of the above circumstances, and is a method of forming a coating film made of an inorganic material on a substrate, which can efficiently increase the thickness of the coating film, and the thickness of the coating film is large. Even if it becomes, it aims at providing the manufacturing method of the board | substrate with a coating film which a crack or film | membrane peeling does not produce easily.

The gist of the present invention is the following [1] to [11].
[1] A coating liquid containing inorganic particles, an alkoxysilane hydrolyzate, a liquid medium containing at least one of a polyhydric hydroxyl group-containing compound and water, and having an average aggregate particle diameter of the inorganic particles of less than 100 nm is prepared. Preparing a substrate; holding the substrate at 200 to 650 ° C .; spraying the coating liquid onto the substrate; obtaining a substrate with a coating film;

[2] A step of spraying a coating liquid containing inorganic particles, an alkoxysilane hydrolyzate, and a liquid medium onto a substrate maintained at 200 to 650 ° C., wherein the average aggregate particle diameter of the inorganic particles is less than 100 nm A method for producing a coated substrate, wherein the liquid medium contains at least one of a polyhydric hydroxyl group-containing compound and water.

[3] The method for producing a coated substrate according to [1] or [2], wherein the liquid medium is a polyvalent hydroxyl group-containing compound or a mixture of water and a polyvalent hydroxyl group-containing compound.
[4] The method for producing a coated substrate according to any one of [1] to [3], wherein the inorganic particles are silica particles.
[5] The method for producing a coated substrate according to any one of [1] to [4], wherein the inorganic particles are chain particles.
[6] The method for producing a coated substrate according to any one of [1] to [5], wherein the substrate is a glass substrate.
[7] The method for producing a coated substrate according to any one of [1] to [6], wherein the alkoxysilane hydrolyzate is tetraethoxysilane or a tetramethoxysilane hydrolyzate.
[8] The method for producing a coated substrate according to any one of [1] to [7], wherein the polyvalent hydroxyl group-containing compound is diethylene glycol, triethylene glycol, or tetraethylene glycol.
[9] The ratio of the inorganic particles is 3 to 30% by mass out of 100% by mass of the solid content of the coating liquid (total of inorganic particles and alkoxysilane hydrolyzate in the coating liquid). The manufacturing method of the board | substrate with a coating film as described in any one of [8].
[10] The method for producing a substrate with a coating film according to any one of [1] to [9], wherein the thickness of the coating film is 100 nm or more and 10 μm or less.
[11] The method for producing a substrate with a coating film according to any one of [1] to [10], wherein the coating film has a Martens hardness of 400 to 1200 N / mm ² .

According to the method for manufacturing a substrate with a coating film of the present invention, it is possible to efficiently and thickly form a coating film made of an inorganic material while preventing the occurrence of cracks or film peeling.

It is a scanning electron micrograph of the board | substrate with a coating film obtained in the Example, (A) is a cross-sectional image, (B) is a surface image. It is a scanning electron micrograph of the board | substrate with a coating film obtained in the Example, (A) is a cross-sectional image, (B) is a surface image. It is a scanning electron micrograph of the board | substrate with a coating film obtained in the Example, (A) is a cross-sectional image, (B) is a surface image. It is a scanning electron micrograph of the board | substrate with a coating film obtained in the Example, (A) is a cross-sectional image, (B) is a surface image. It is a scanning electron micrograph of the board | substrate with a coating film obtained by the reference example, (A) is a cross-sectional image, (B) is a surface image. It is a scanning electron micrograph of the board | substrate with a coating film obtained by the reference example, (A) is a cross-sectional image, (B) is a surface image. It is the schematic which shows an example of a glass manufacturing apparatus.

The average aggregate particle diameter of inorganic particles in the present specification is an average particle diameter obtained by measuring inorganic particles in a dispersion medium by a dynamic light scattering method. When the inorganic particles in the dispersion medium are monodispersed particles that are not aggregated, the value of the average aggregated particle diameter obtained by this method means the value of the average primary particle diameter.
The temperature of the substrate in this specification is the surface temperature on the side where the coating liquid is applied.
The thickness (film thickness) of the coating film in this specification is defined by an interval in a direction parallel to the substrate surface (in-plane direction) in an image obtained by observing a cross section of the substrate with a coating film with a scanning electron microscope. The film thickness from the surface of the substrate to the surface of the coating film was measured at three points of 1.5 μm, and the average value (average film thickness) of the film thicknesses at the three points was determined as the film thickness (film thickness). It was.

<Substrate with coating film>
The substrate with a coating film in the present invention is sprayed with a liquid containing inorganic particles, an alkoxysilane hydrolyzate and a liquid medium (hereinafter also referred to as a coating liquid (X)) on a substrate maintained at 200 to 650 ° C. By doing so, a coating film (hereinafter sometimes referred to as a coating film (Y)) is formed.
<Board>
The substrate is not particularly limited as long as it can be heated to 200 to 650 ° C. For example, a glass substrate is suitable.
Examples of the material for the glass substrate include soda lime silica glass, borosilicate glass, and aluminosilicate glass.

The substrate may have a layer other than the coating film (Y) on the surface of the substrate body. Moreover, you may have layers other than a coating film (Y) on a coating film (Y).
For example, a functional layer may be provided on the surface of the substrate body, and a coating film (Y) may be formed on the functional layer.
Examples of the functional layer include an undercoat layer, a stress relaxation layer, an adhesion improving layer, and a protective layer. The undercoat layer functions as an alkali barrier layer or a wide band low refractive index layer. The undercoat layer is preferably a layer formed by applying an undercoat coating liquid containing alkoxysilane or a hydrolyzate thereof (sol-gel silica) to the surface of the substrate body. The stress relaxation layer is a material for suppressing cracks arising from the difference in thermal expansion coefficient between the glass substrate and the coating film (Y), and is a material having a thermal expansion coefficient intermediate between the glass and the coating film (Y). Preferably it is formed.

<Inorganic particles>
As the inorganic particles, those having an average aggregate particle diameter of less than 100 nm are used. When the average agglomerated particle diameter of the inorganic particles is less than 100 nm, the coating liquid (X) contains the inorganic particles, so that the film deposition efficiency is improved and the effect of increasing the film thickness of the coating film (Y) is sufficient. Easy to obtain. The lower limit of the average agglomerated particle diameter is preferably 1 nm from the viewpoint of dispersion stability, and more preferably 3 nm.

Inorganic particles include metal oxide particles or metal particles. Inorganic particles may be used alone or in combination of two or more.
From the viewpoint of availability, silica particles (silicon oxide particles) are preferably used as the inorganic particles.
Moreover, when what has various functions as an inorganic particle is used, the coating film (Y) which acts as a functional layer will be obtained. As an example of the material of the inorganic particle which has a function, the following are mentioned according to a function.
UV shielding: zinc oxide, cerium oxide, etc.
Infrared shielding: Indium tin oxide (ITO), antimony tin oxide (ATO), tungsten oxide, erbium, etc.
Antistatic: ITO, ATO, silver, etc.
Photocatalyst: titanium oxide and the like.
Wavelength conversion: zinc oxide, europium doped zinc oxide, zinc sulfide, europium doped zinc sulfide, indium phosphide, bismuth doped calcium sulfide, europium doped calcium fluoride, europium doped yttrium vanadate, and the like.
It is preferable that the function imparted to the coating film (Y) is a function that provides a higher effect as the film thickness is larger in that the effect of applying the present invention is greater. Examples of the functional layer having a higher effect as the film thickness is larger include a light scattering layer, an alkali barrier layer, an ultraviolet absorption layer, and an infrared absorption layer.

Examples of the shape of the inorganic particles include a spherical shape, an elliptical shape, a needle shape, a rod shape, a plate shape, a rod shape, a conical shape, a columnar shape, a cubic shape, a rectangular shape, a diamond shape, a star shape, and an indefinite shape. In addition, the inorganic particles may exist in a state where each particle is independent, each particle may be linked in a chain, or each particle may be aggregated.
In particular, by using chain particles in which each inorganic particle is connected in a chain, the coating efficiency when forming a coating film by spraying the coating liquid (X) onto a heated substrate is greatly increased. To improve. The reason is that the alkoxysilane hydrolyzate produced when the coating liquid (X) is supplied onto the heated substrate by forming chain-structured inorganic particles and a network structure with the alkoxysilane hydrolyzate. It is conceivable that the vaporization or scattering of the water is suppressed.
In the chain particles, the number of linked inorganic particles is preferably 2 to 1000, more preferably 3 to 500. In the chain particles, the inorganic particles may be linearly linked or branched.

The inorganic particles only have to have an average aggregate particle diameter of less than 100 nm, and may be core-shell type particles in which one component is coated with another component. The aggregate particle diameter of the core-shell type particles means the outer diameter of the shell.
The inorganic particles may be surface-treated with a surfactant, a polymer dispersant, a silane coupling agent or the like. The aggregate particle diameter of the inorganic particles after the surface treatment is preferably 1 to 100 nm.
Inorganic particles are inert to heat of 400 to 650 ° C., that is, when a dispersion liquid containing only inorganic particles and not containing an alkoxysilane hydrolyzate is supplied on a heated substrate, no film is formed. Or a film having a significantly low film deposition efficiency.

<Alkoxysilane hydrolyzate>
The alkoxysilane hydrolyzate is obtained by hydrolyzing alkoxysilane with a catalyst in the presence of one or more hydroxy compounds selected from the group consisting of water and a polyhydric hydroxyl group-containing compound. The polyvalent hydroxyl group-containing compound used here is the same as that described later. As the hydroxy compound, water is preferred. The alkoxysilane hydrolyzate may contain unreacted alkoxysilane. The hydrolyzate of alkoxysilane is a precursor of silicon oxide, and silicon oxide is obtained by firing this.

Examples of the alkoxysilane include tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc.), monoalkyltrialkoxysilane (methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltrimethoxysilane). Ethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, etc.), dialkyl dialkoxysilane (dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane, etc.) , Trialkyl monoalkoxysilane (trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, triethylethoxy Run, tripropylmethoxysilane, tripropylethoxysilane, etc.), monoaryltrialkoxysilane (phenyltrimethoxysilane, phenyltriethoxysilane, etc.), diaryl dialkoxysilane (diphenyldimethoxysilane, diphenyldiethoxysilane, etc.), triaryl Monoalkoxysilane (triphenylmethoxysilane, triphenylethoxysilane, etc.), alkoxysilane having a perfluoropolyether group (perfluoropolyethertriethoxysilane, etc.), alkoxysilane having a perfluoroalkyl group (perfluoroethyltriethoxysilane, etc.), Alkoxysilanes having vinyl groups (vinyltrimethoxysilane, vinyltriethoxysilane, etc.), alkoxysilanes having epoxy groups (2- 3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane), having acryloyloxy group Examples include alkoxysilane (3-acryloyloxypropyltrimethoxysilane and the like).
Of these, tetraalkoxysilane is preferable, and tetraethoxysilane or tetramethoxysilane is more preferable from the viewpoint of high hydrolysis rate and high productivity.
Alkoxysilane may be used alone or in combination of two or more.

Hydrolysis of the alkoxysilane is performed using a hydroxy compound (preferably water) and a catalyst. It is preferable to use an acid or an alkali as the catalyst. Examples of the acid include inorganic acids (such as nitric acid, sulfuric acid, and hydrochloric acid) and organic acids (such as formic acid, oxalic acid, tartaric acid, citric acid, monochloroacetic acid, dichloroacetic acid, and trichloroacetic acid). Examples of the alkali include ammonia, sodium hydroxide, potassium hydroxide and the like. The catalyst is preferably an acid from the viewpoint of long-term storage. Moreover, as a catalyst, what does not prevent dispersion | distribution of an inorganic particle is preferable.
When the coating liquid (X) is prepared, a hydroxy medium is used as a liquid medium, and an alkoxysilane and a catalyst are present in the liquid medium, whereby a liquid medium containing an alkoxysilane hydrolyzate is obtained.

<Liquid medium>
The liquid medium contains at least one of a polyhydric hydroxyl group-containing compound and water. That is, at least a polyvalent hydroxyl group-containing compound, water, or a mixture thereof is used as the liquid medium.
When the liquid medium contains neither a polyvalent hydroxyl group-containing compound nor water, even if the coating liquid is sprayed onto the substrate, no coating film is formed on the substrate, or even if a coating film is formed, the film is deposited. Efficiency is significantly reduced.
In particular, it is preferable to use a polyvalent hydroxyl group-containing compound as the liquid medium in that good film formation efficiency is easily obtained when the coating liquid is sprayed onto the substrate.
In addition, when the alkoxysilane is hydrolyzed in a liquid medium, it is preferable to use both a polyhydric hydroxyl group-containing compound and water as the liquid medium.

The polyhydric hydroxyl group-containing compound is a compound having two or more hydroxyl groups in one molecule, and for example, one or more selected from the group consisting of polyhydric alcohols, alkanolamines, and phenol derivatives can be used.
The polyhydric alcohol is preferably one or more selected from the group consisting of (poly) alkylene glycol, trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, sorbitol, dipentaerythritol, and sucrose.
The alkanolamine is preferably at least one selected from the group consisting of monoethanolamine, propanolamine, and diethanolamine.
The phenol derivative is preferably at least one selected from the group consisting of bisphenol A, catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, and hexahydroxybenzene.
The (poly) alkylene glycol in this specification is an alkylene glycol represented by HO—C _n H _2n —OH (n is an integer of 1 or more), or HO— (C _n H _2n —O—) _m H ( n is an integer of 1 or more, and m is an integer of 2 or more).

Among these, (poly) alkylene glycol is preferable in that good film formation efficiency of the coating film can be easily obtained. As the (poly) alkylene glycol, a (poly) alkylene glycol having a molecular weight of 300 or less is preferable.
The (poly) alkylene glycol is more preferably at least one selected from the group consisting of alkylene glycol, dialkylene glycol (m = 2), trialkylene glycol (m = 3), and tetraalkylene glycol (m = 4). In particular, trialkylene glycol or tetraalkylene glycol is preferable, and tetraalkylene glycol is preferable from the viewpoint that good film formation efficiency of the coating film can be easily obtained.
The carbon number (n) of the alkylene group (—C _n H _2n —) in the (poly) alkylene glycol is preferably 2 to 6 in terms of being able to disperse the inorganic fine particles satisfactorily and in terms of viscosity (handleability). 4 is more preferable.
(Poly) alkylene glycol is preferably (poly) ethylene glycol, (poly) propylene glycol, or (poly) tetramethylene glycol. Diethylene glycol, triethylene glycol, or tetraethylene glycol is particularly preferred.

The liquid medium may contain other components other than water or (poly) alkylene glycol as long as the effects of the present invention are not impaired.
Examples of other components include monohydric alcohols such as ethanol and 2-propanol, ketones, ethers, cellosolves, esters, glycol ethers, nitrogen-containing compounds, and sulfur-containing compounds.
When the liquid medium contains other components, the content thereof is preferably more than 0% by mass and 30% by mass or less, and more preferably 10% by mass or less with respect to the total amount of the liquid medium.

<Manufacturing method of substrate with coating film>
[Preparation of coating solution]
First, a coating liquid containing inorganic particles, an alkoxysilane hydrolyzate, and a liquid medium is prepared.
The inorganic particles are preferably used in the form of a dispersion previously dispersed in a liquid medium. For example, a commercially available silica sol (colloidal silica) in which silica particles are dispersed in water can be used for preparing the coating liquid.
Preferably, alkoxysilane is hydrolyzed in a liquid medium containing at least a hydroxy compound in the presence of a catalyst to obtain a liquid medium containing an alkoxysilane hydrolyzate, and a dispersion liquid of inorganic particles is added to this to obtain a uniform medium. A method of obtaining a coating liquid by mixing with the above can be used.

The solid content concentration of coating liquid (total concentration of inorganic particles and alkoxysilane hydrolyzate (in terms of SiO ₂ ) in the coating liquid) is based on the film deposition efficiency of the coating film and the viscosity (handleability) of the coating liquid. 0.3 to 70% by mass is preferable, and 3 to 25% by mass is more preferable.

Of the solid content of the coating liquid (total of inorganic particles and alkoxysilane hydrolyzate in the coating liquid), the proportion of inorganic particles is preferably 1 to 60 mass%, more preferably 3 to 30 mass%. When the ratio of the inorganic particles is 1% by mass or more, the coating liquid (X) contains the inorganic particles, so that the deposition efficiency is improved and the film thickness of the coating film (Y) is sufficiently increased. Easy to obtain. When the proportion of the inorganic particles is 60% by mass or less, the aggregation of the inorganic particles is satisfactorily suppressed and a film in which the inorganic particles are uniformly dispersed is easily obtained.

The proportion of the alkoxysilane hydrolyzate (SiO ₂ equivalent solid content) is 40 to 99 mass% of 100 mass% of the solid content of the coating liquid (total of inorganic particles and alkoxysilane hydrolyzate in the coating liquid). 70 to 97% by mass is more preferable. When the proportion of the alkoxysilane hydrolyzate is 40% by mass or more, the deposition efficiency is likely to be sufficiently high, and a thick coating film is easily obtained. When the ratio of the alkoxysilane hydrolyzate is 99% by mass or less, the coating liquid (X) contains inorganic particles, so that the effect of increasing the film thickness of the coating film (Y) is easily obtained.

[Application of coating solution]
The prepared coating solution is applied to the substrate by spraying.
The spraying method of the coating liquid is preferably a spraying method in which the coating liquid is sprayed using a nozzle (such as a spray gun).
Specific application methods by the spray method include the following methods (i), (ii), (iii) and the like. The method (ii) is preferable because the number of steps is small and a substrate with a coating film can be produced more efficiently.

(I) A method of spraying the coating liquid from the nozzle onto the substrate while moving the nozzle above the fixed substrate.
(Ii) A method of spraying a coating liquid from a nozzle onto a belt-like substrate (for example, a glass ribbon) moving in one direction.
(Iii) A method in which the coating liquid is sprayed from the nozzle onto the substrate while moving the nozzle over a belt-like substrate (for example, a glass ribbon) moving in one direction.

The temperature of the substrate when applying the coating liquid is 200 to 650 ° C., preferably 300 to 600 ° C. When the coating liquid is sprayed onto the substrate in the temperature range, the alkoxysilane hydrolyzate is baked to become silicon oxide, and a coating film (Y) is formed on the substrate.
Since the alkoxysilane hydrolyzate on a board | substrate is baked in a short time as the temperature of a board | substrate is 200 degreeC or more, productivity is good. The temperature of the substrate is preferably 300 ° C. or higher. The upper limit of the temperature of the substrate is not particularly limited, but if it is too high, the equipment for heating becomes large and the material of the substrate is also limited. Therefore, it is preferable that the temperature does not cause these disadvantages, for example, 650 ° C is preferred.
In the present invention, the temperature of the substrate is maintained at a predetermined temperature within the range of 200 to 650 ° C., and the coating liquid is sprayed thereon. The temperature of the substrate may be controlled to a predetermined temperature within a range of 200 to 650 ° C. at least immediately before the coating liquid is sprayed.

As the above method (ii) or (iii), for example, when the substrate is a glass substrate, the molten glass is formed into a glass ribbon, the glass ribbon is slowly cooled, and then cut to produce a glass substrate. In the method, a method of forming a coating film (Y) on the glass ribbon by applying a coating liquid to the glass ribbon can be used. The glass ribbon is then cut. The glass substrate in this case is preferably a green glass substrate that is not strengthened.
That is, a method of forming a coating film (Y) on a glass ribbon by applying a coating liquid (X) to a glass ribbon to be a glass substrate and baking a hydrolyzate of alkoxysilane can be used.

In this method (ii) or (iii), the glass ribbon obtained by molding the molten glass in a float bath has a glass ribbon of 200 to 650 between the float bath and the slow cooling step or during the slow cooling step. It is preferable to spray the coating liquid at a position in the temperature range of ° C. When manufacturing a glass substrate by the float process, the temperature of the glass ribbon at the position immediately after the float bath is usually about 650 ° C., although it depends on the glass composition of the glass substrate, and the glass ribbon exiting the float bath is a slow cooling step. And is cooled to 400 ° C. or lower during the slow cooling process.
Setting the spraying position of the coating liquid in the float bath is not practical because it may contaminate the atmosphere in the float bath. Also from this point, the temperature of the substrate when spraying the coating liquid is 650 ° C. or less. It is preferable that
In this method (ii) or (iii), the glass ribbon obtained by forming molten glass by drawing down is coated at a position where the glass ribbon is in the temperature range of 200 to 650 ° C. during the slow cooling process. It is also preferable to spray the liquid. Examples of the draw down molding method include a fusion draw method, a tube draw method, and a slot draw method.

<Coating film (Y)>
The coating film (Y) thus formed on the substrate comprises a silicon oxide phase obtained by baking the alkoxysilane hydrolyzate at a predetermined temperature of 200 to 650 ° C. and inorganic particles. The phase of silicon oxide plays a role of a binder for fixing inorganic particles to the substrate. Therefore, superior heat resistance and weather resistance can be obtained as compared with the case where the binder is an organic material.
The coating film (Y) may be a film composed of silicon oxide and inorganic particles, and may be a film formed by continuously spraying one type of coating liquid on the substrate. May be a multilayer film formed by intermittent spraying, or may be a multilayer film formed by spraying two or more types of coating liquids having different kinds of inorganic particles in order.
The thickness (film thickness) of the coating film (Y) is preferably 100 nm or more, and more preferably 1000 nm or more (1 μm or more). When the thickness of the coating film (Y) is 100 nm or more, the function of the coating film (Y) is sufficiently exhibited. In addition, when a coating film (Y) is a multilayer film, let the thickness of a coating film (Y) be the film thickness of the layer formed by one spraying. However, one spray means a continuous series of sprays. That is, when spraying is performed again after a sufficient time interval after spraying, it is considered as multiple times. The upper limit of the integrated thickness when the coating film (Y) is a multilayer film is not particularly limited, but is preferably 50 μm or less, more preferably 30 μm or less, and particularly preferably 10 μm or less from the viewpoint of productivity.
Hardness of the coating film (Y) is preferably from 200 ~ 3000N / mm ² in Martens hardness, and more preferably 400 ~ 1200N / mm ^2. By increasing the temperature at the time of spraying, the hardness of the film can be increased.

(Glass manufacturing equipment)
FIG. 7 is a schematic view showing an example of a glass production apparatus suitable for producing a glass substrate with a coating film in which a coating film is formed on the glass substrate using the method of the present invention.
The glass manufacturing apparatus 20 melts the glass raw material to form the molten glass 30 and floats the molten glass 30 supplied from the melting furnace 22 on the surface of the molten tin 24, thereby causing the molten glass 30 to become the glass ribbon 32. A float bath 26 for forming the glass ribbon 32, a slow cooling furnace 28 for gradually cooling the glass ribbon 32, and an air disposed between the outlet of the float bath 26 and the entrance of the slow cooling furnace 28 and above the glass ribbon 32. A spray gun 34 of the type.

A coating liquid is sprayed from a spray gun 34 onto a glass ribbon 32 moving at a predetermined conveying speed at a position where the surface temperature of the glass ribbon 32 is 200 to 650 ° C. between the float bath 26 and the slow cooling furnace 28. An inorganic film is formed on the glass ribbon 32.
The glass ribbon 32 exiting the slow cooling furnace 28 is cut by a cutting device (not shown) to form a glass substrate with a coating film.

<Effect>
In the method for producing a substrate with a coating film of the present invention, a coating liquid containing inorganic particles of less than 100 nm, an alkoxysilane hydrolyzate, and a specific liquid medium is sprayed on a substrate maintained at 200 to 650 ° C. By doing so, the inorganic film can be formed thick while preventing the occurrence of cracks or film peeling.

As shown in Examples described later, by using inorganic particles having an average aggregate particle diameter of less than 100 nm, a structure in which inorganic particles are stacked on a substrate via a continuous phase made of silicon oxide is easily obtained, and a film It is easy to obtain a coating film having a large thickness.
When a structure in which inorganic particles are stacked through a continuous phase composed of such silicon oxide is obtained, the larger the average aggregated particle diameter of the inorganic particles contained in the coating liquid, the higher the film deposition efficiency, and the smaller the average aggregated particle diameter. The surface smoothness is improved and a denser coating film is obtained.
Furthermore, the use of chain particles can dramatically increase the deposition efficiency.

Also, since a hydrolyzate of alkoxysilane is used as a precursor of silicon oxide contained in the coating liquid instead of the conventional organopolysiloxane, a polar liquid medium can be used. Select inorganic particles because inorganic particles that can be dispersed in a polar liquid medium have more types than inorganic particles that can be dispersed in a non-polar liquid medium, and there is no need for surface treatment such as hydrophobization. The width of becomes wide.

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.
[Example 1]
To triethylene glycol, tetraethoxysilane (manufactured by Kanto Chemical Co., Inc., SiO ₂ conversion solid content: 99.9% by mass) is added so as to be 30% by mass in the coating liquid, and nitric acid (70% by mass aqueous solution) is further added. It added so that it might become 0.35 mass% in a coating liquid, and it stirred for 1 hour. Next, a chain silica sol (manufactured by Nissan Chemical Industries, (product name: Snowtex OUP), average aggregated particle size: 65 nm, solid content: 15% by mass, medium: water) becomes 6.7% by mass in the coating liquid. In addition, the mixture was stirred for 5 to 10 minutes, the solid content concentration in terms of SiO ₂ : 9.65% by mass, the ratio of silica particles in the solid content: 10.4% by mass, the hydrolyzate of alkoxysilane in the solid content ( Ratio of solid content in terms of SiO ₂ : A coating liquid of 89.6% by mass was obtained.

As a coating apparatus, KM-100 (manufactured by SPD Laboratory) was used. As the glass substrate, 10 cm × 10 cm × 4 mm high transmission glass (soda lime silica glass, manufactured by Asahi Glass Co., Ltd.) was used.
A glass substrate was placed on the stage, and a heater was installed on the back side of the stage without contact with the stage. The glass substrate was heated to 400 ° C. through the stage by the radiant heat of the heater.
The temperature of the glass substrate was measured by bringing a thermocouple into contact with one side of the glass substrate. Since the glass substrate was heated for a sufficient time before spraying the coating liquid with the spray gun, the temperature measured here may be regarded as almost the same as the surface temperature of the glass substrate.
After the temperature of the glass substrate was raised to 400 ° C., the coating liquid was sprayed onto the glass substrate from a spray gun disposed above the glass substrate. When spraying the coating liquid from the spray gun, the liquid feed pressure to the spray gun was adjusted so that the liquid feed speed was 0.3 to 0.6 mL / second, and the spray pressure was 1 MPa. The coating time was 45 seconds. The stage, glass substrate, and spray gun were sprayed in a state surrounded by an explosion-proof device, and the ambient temperature was not adjusted.
Thus, a substrate with a coating film was obtained, in which a coating film composed of silica particles and a calcined product of hydrolyzed alkoxysilane (silicon oxide) was formed on the glass substrate.

FIG. 1 is a photograph of an image obtained by observing the obtained substrate with a coating film with a scanning electron microscope, where (A) is a cross-sectional image and (B) is a surface image (hereinafter the same). It was 1.7 micrometers when the average value of the film thickness (distance illustrated with an arrow in a figure) from the surface of a glass substrate to the surface of a coating film was measured from the cross-sectional image of (A).
The shape of the silica particles used in this example, the average aggregate particle diameter, the coating time, and the film thickness (average film thickness) of the obtained coating film are shown in Table 1 (hereinafter the same).
Moreover, the surface smoothness of the coating film was evaluated by the following method. The results are shown in Table 1.
The obtained coating film had a Martens hardness of 830 N / mm ² . The Martens hardness was measured with a microhardness measuring device (PICODERTOR HM500 manufactured by Fischer Instruments). An indentation depth of 0.1 μm and an indentation time of 20 seconds were measured at five points at different locations to obtain an average value.

[Method for evaluating surface smoothness]
Using a shape measurement laser microscope (controller part VK-100 (product name), microscope part VK-110 (product name)) manufactured by Keyence Corporation, the film surface was observed at a magnification of 100 times, and 100 μm at three arbitrary points. The maximum height roughness (Rz) in the length was measured, and the average value of Rz at the three points was determined.

[Examples 2 to 4, Reference Example 1]
In Example 2, instead of the chain silica sol in Example 1, spherical silica sol (manufactured by Nissan Chemical Industries, (product name: Snowtex OS), average aggregated particle size: 11 nm, solid content: 20% by mass, medium: water) This was added so that it might become 5.0 mass% in a coating liquid.
In Example 3, instead of the chain silica sol in Example 1, spherical silica sol (manufactured by Nissan Chemical Co., Ltd., (product name: Snowtex O-40), average aggregate particle size: 30 nm, solid content: 40% by mass, medium: This was added to 2.5% by mass in the coating solution.
In Example 4, instead of the chain silica sol in Example 1, spherical silica sol (manufactured by Nissan Chemical Industries, (product name: Snowtex OL), average aggregated particle size: 50 nm, solid content: 20% by mass, medium: water) This was added so that it might become 5.0 mass% in a coating liquid.
In Reference Example 1, instead of the chain silica sol in Example 1, spherical silica sol (manufactured by Nissan Chemical Co., Ltd. (product name: Snowtex MP-2040), average aggregate particle size: 200 nm, solid content: 40% by mass, medium: This was added to 2.5% by mass in the coating solution.
Except for the above, a substrate with a coating film was obtained in the same manner as in Example 1, observed with a scanning electron microscope, measured for film thickness, and evaluated surface smoothness. The results are shown in Table 1.

[Reference Example 2]
In Reference Example 2, instead of the chain silica sol in Example 1, spherical silica sol (manufactured by Nissan Chemical Co., Ltd., (Product name: Snowtex MP-4540M), average aggregate particle size: 450 nm, solid content: 40% by mass, medium: This was added to 2.5% by mass in the coating solution. The application time was changed to 21 seconds.
Except for the above, a substrate with a coating film was obtained in the same manner as in Example 1, observed with a scanning electron microscope, measured for film thickness, and evaluated surface smoothness. The results are shown in Table 1.

[Comparative Example 1]
Comparative Example 1 is an example in which the coating liquid does not contain inorganic particles. That is, tetraethoxysilane (manufactured by Kanto Chemical Co., Inc., SiO ₂ conversion solid content: 99.9% by mass) was added to triethylene glycol so as to be 33.5% by mass in the coating solution, and nitric acid (70% by mass) was further added. the aqueous solution), added in an amount of 0.35 wt% in the coating solution, and stirred for 1 hour, SiO ₂ in terms of solid concentration: was obtained 9.65 mass% of the coating solution.
Using the obtained coating solution, a substrate with a coating film was obtained in the same manner as in Example 1, and observed with a scanning electron microscope, the film thickness was measured, and the surface smoothness was evaluated. The results are shown in Table 1.

As shown in the results of Table 1, in Examples 1 to 4, an inorganic film having a thickness of 400 nm or more could be formed on the substrate in a coating time of 45 seconds, and good film deposition efficiency was obtained. Further, no cracks or film peeling occurred in the coating film.
Comparing Examples 2 to 4, it can be seen that the larger the average aggregate particle size of the silica particles, the larger the film thickness of the coating film, that is, the higher the film deposition efficiency in the same coating time. On the other hand, the smaller the average agglomerated particle diameter of the silica particles, the higher the smoothness of the surface, and a denser coating film can be obtained as can be seen from the photograph.
It can be seen that Example 1 using chain silica had a larger film thickness than Examples 2 to 4, and the deposition efficiency was dramatically improved. The coating film of Example 1 also had good surface smoothness.

As can be seen from the results of Reference Examples 1 and 2, when the average aggregate particle diameter of the silica particles is increased to 100 nmn or more, it becomes difficult to obtain a structure in which the silica particles are stacked through a continuous phase made of silicon oxide, and the film thickness is reduced. It turns out that it becomes difficult to make it thick.
In Comparative Example 1 in which no silica particles were added, the film thickness was significantly smaller than in Examples 1 to 4, and almost no coating was applied.

The coated substrate produced in the present invention has high visible light transmittance and good UV durability, and covers solar cells, display protective plates, automotive glass, railway vehicle glass, and ships. Widely used as glass for construction and glass for building materials.
It should be noted that the entire content of the specification, claims, drawings and abstract of Japanese Patent Application No. 2013-142052 filed on July 5, 2013 is cited herein as the disclosure of the specification of the present invention. Incorporated.

20 Glass Manufacturing Equipment 22 Melting Kiln 24 Molten Tin 26 Float Bath 28 Slow Cooling Kiln 30 Molten Glass 32 Glass Ribbon 34 Spray Gun

Claims

Preparing a coating liquid comprising inorganic particles, an alkoxysilane hydrolyzate, a liquid medium containing at least one of a polyhydric hydroxyl group-containing compound and water, and having an average aggregate particle diameter of the inorganic particles of less than 100 nm;
Preparing a substrate;
Holding the substrate at 200-650 ° C .;
Spraying the coating liquid onto the substrate;
The manufacturing method of a board | substrate with a coating film which obtains a board | substrate with a coating film.
Spraying a coating liquid containing inorganic particles, an alkoxysilane hydrolyzate, and a liquid medium onto a substrate maintained at 200 to 650 ° C .;
The average particle diameter of the said inorganic particle is less than 100 nm, The said liquid medium contains the polyhydric hydroxyl group containing compound and at least one of water, The manufacturing method of the board | substrate with a coating film.
The method for producing a substrate with a coating film according to claim 1 or 2, wherein the liquid medium is a polyvalent hydroxyl group-containing compound or a mixture of water and a polyvalent hydroxyl group-containing compound.
The method for producing a substrate with a coating film according to any one of claims 1 to 3, wherein the inorganic particles are silica particles.
The method for producing a substrate with a coating film according to any one of claims 1 to 4, wherein the inorganic particles are chain particles.
The method for producing a substrate with a coating film according to any one of claims 1 to 5, wherein the substrate is a glass substrate.
The method for producing a coated substrate according to any one of claims 1 to 6, wherein the alkoxysilane hydrolyzate is tetraethoxysilane or a tetramethoxysilane hydrolyzate.
The method for producing a coated substrate according to any one of claims 1 to 7, wherein the polyvalent hydroxyl group-containing compound is diethylene glycol, triethylene glycol, or tetraethylene glycol.
The ratio of the inorganic particles is 3 to 30% by mass out of 100% by mass of the solid content of the coating liquid (total of inorganic particles and alkoxysilane hydrolyzate in the coating liquid). The manufacturing method of the board | substrate with a coating film of one term.
The method for producing a substrate with a coating film according to any one of claims 1 to 9, wherein the thickness of the coating film is 100 nm or more and 10 µm or less.
The method for producing a substrate with a coating film according to any one of claims 1 to 10, wherein the hardness of the coating film is 400 to 1200 N / mm 2 in terms of Martens hardness.