JP2018176058A - Manufacturing method of laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a laminate which has a good appearance with less striped thickness unevenness, and exhibits good antireflection performance.SOLUTION: A manufacturing method of a laminate having an antireflection film on at least one surface of a base material includes: a first process of forming a thin film by coating at least the one surface of the base material with a coating liquid containing metal oxide particles (A), polymer particles (B), and at least one kind of solvent (D) by a reverse roll coater; a second process of removing the solvent with warm air at 300°C or lower; and a third process of forming an air gap by baking at 500-700°C to form the antireflection film. A capillary number Ca is 1-80 where the capillary number is calculated by (the expression 1): Ca=μV/σ (in the expression, μ is viscosity of the coating liquid, σ is surface tension, V is a relative speed of a coating roll rotation speed (Vt) of the reverse roll coater with respect to a base material conveying speed (Vb)).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing a laminate.

  In recent years, global awareness has raised environmental awareness, and new energy systems that do not generate carbon dioxide and other greenhouse gases are attracting attention. Among them, solar cells are particularly attracting attention because of their excellent safety and ease of handling.

  In order to increase the output of a solar cell, it is known to form an antireflective film on the surface of a solar cell cover glass to increase the transmittance.

For example, Patent Document 1 discloses an antireflective film having excellent antifouling properties, in which pores are formed by using beaded silica.
In addition, Patent Document 2 discloses an anti-reflection film excellent in antifouling property, in which pores are formed by burning away an organic component in a coating film.

The roll coating method is known as a formation method of these anti-reflective films. The roll coating method is a method of applying a coating liquid on a substrate by transferring the coating liquid on the surface of the coating roll on the substrate transported in a predetermined direction.
For example, Patent Document 3 discloses, as a roll coating method capable of forming a metal oxide film having a uniform film thickness, a metal compound and an organic solvent on a substrate transported in a predetermined direction by a coating roll of a reverse roll coater. A method of forming a metal oxide film by applying and baking a coating composition containing Further, in Patent Document 3, the concentration (in terms of oxide) of the metal compound is 0.1 to 10% by mass, the viscosity is 0.1 to 100 mPa · s, and the rotation of the coating roll is performed. The speed is 2 to 55 m / min, the transport speed of the substrate is 1 to 30 m / min, and the rotation speed of the coating roll is disclosed to be faster than the transport speed of the substrate.
Further, in Patent Document 4, using a coating solution having a viscosity of 1.0 to 10.0 mPa · s, the rotational speed of the coating roll when applying this coating solution on the substrate is higher than the transport speed of the substrate. A method for producing an article with a low reflection film, which slows down, has been proposed.

International Publication No. 2013/111783 Unexamined-Japanese-Patent No. 2015-108601 Japanese Patent Application Laid-Open No. 07-068219 International Publication No. 2013/051620

There is a need for a novel method of manufacturing a laminate, which has a good appearance with reduced stripe thickness unevenness and a good antireflective performance.
In particular, when the water content of the coating composition exceeds 3% by mass, only by decreasing the viscosity of the coating composition by the above-described conventional method, the streaked film thickness unevenness of the coating film is suppressed. It was not enough to obtain a coating film having a good appearance.

The present invention is to provide a novel method for producing a laminate having an antireflective film, which can coat a coating liquid containing a solvent uniformly and without unevenness in film thickness on a substrate. The purpose of
Further, the present invention provides a method for producing a laminate having an antireflective film, which can be uniformly coated on a substrate with a coating liquid containing water in an amount of more than 3% by mass as a solvent without unevenness in film thickness. The second purpose is to provide

As a result of intensive studies to solve the above problems, the inventors of the present invention have found that by controlling the capillary number (Ca) of the coating solution containing the solvent within a predetermined range, it is possible to reduce streaked film thickness unevenness. The inventors have found that a laminate having an appearance and good antireflective performance can be obtained, thus completing the present invention.
Also, the present inventors control the capillary number (Ca) of the coating solution containing the solvent within a predetermined range, and further, if necessary, the ratio of the coating roll rotation speed of the reverse roll coater to the transport speed of the substrate. By adjusting to a range and coating, even when using a coating liquid containing water in an amount of more than 3% by mass as a solvent, a good appearance and a good anti-reflection performance with reduced streaked film thickness unevenness are obtained. It has been found that a laminate having the above can be obtained.

That is, the aspects of the present invention are as follows.
[1]
A method of producing a laminate having an antireflective film on at least one side of a substrate, the method comprising
A coating liquid containing metal oxide particles (A), polymer particles (B), and at least one or more solvents (D) is applied to at least one surface of a substrate by a reverse roll coater to form a thin film Process,
The second step of removing the solvent with hot air of 300 ° C. or less, and the third step of firing at a temperature of 500 to 700 ° C. to form a void, thereby forming an antireflective film,
(Formula 1): Ca = μV / σ (where, μ: viscosity of coating solution, σ: surface tension, V: relative speed of coating roll rotation speed (Vt) of reverse roll coater to substrate transport speed (Vb) The capillary number Ca calculated by the equation is 1 to 80,
Method of manufacturing a laminate.
[2]
The coating solution is a metal oxide particle (A) having a number average particle diameter of 1 nm to 200 nm, a polymer particle (B) having a number average particle diameter of 10 nm to 300 nm, and a hydrolyzate of a hydrolyzable silicon compound (C). And 3% by weight to 80% by weight of water as the solvent (D), the method for producing a laminate according to the above [1].
[3]
The viscosity of the coating solution is 1 to 10 mPa.s. and a surface tension of 15 to 45 mN / m. The method for producing a laminate according to the above [1] or [2].
[4]
[1] to [3], wherein the ratio Vt / Vb of the coating roll rotation speed (Vt) to the base material transfer speed (Vb) of the reverse roll coater is 0.2 to 3.0. The manufacturing method of the laminated body as described in-.
[5]
The laminated body which has an anti-reflective film manufactured by the manufacturing method of the laminated body as described in any one of said [1] thru | or [4] term.
[6]
The cover glass for solar cells containing the laminated body of the said [5] term.
[7]
The solar power generation mirror containing the laminated body of the said [5] term.
[8]
The glass for building materials containing the laminated body of the said [5] term.

ADVANTAGE OF THE INVENTION According to this invention, the laminated body which has the favorable external appearance in which the stripe-like film thickness nonuniformity was reduced, and the favorable antireflection performance is obtained.
Further, according to a preferred embodiment of the present invention, even when a coating liquid containing water in an amount of more than 3% by mass is used as a solvent, a good appearance with reduced streaked film thickness unevenness and a good reflection prevention A laminate having performance is obtained.

FIG. 1 is a schematic view showing one non-limiting example of a reverse roll coater.

Hereinafter, modes for carrying out the present invention will be described in detail.
The following embodiments are exemplifications for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be appropriately modified and implemented within the scope of the gist of the present invention.
In the present specification, “(meth) acrylate” means both an acrylate and a corresponding methacrylate. Also, "(meth) acrylic acid" means both acrylic acid and the corresponding methacrylic acid.

First, various elements used in the method of manufacturing a laminate according to the present invention will be described.
〔Base material〕
The substrate includes, but is not limited to, glass, metal, resin, silicone and the like. Examples of the glass include soda lime glass, borosilicate glass, aluminosilicate glass, alkali-free glass, mixed alkali glass and the like.
As a base material for cover glass of a solar cell, a textured glass sheet having an uneven surface is preferable. As a material of the glass (for example, template glass), white plate glass having a smaller component ratio of iron and higher transparency than that of blue plate glass used for ordinary window glass and the like is preferable.

[Reverse roll coater]
Any known reverse roll coater can be used.
FIG. 1 is a schematic view showing one non-limiting example of a reverse roll coater.
The reverse roll coater has a predetermined gap above the conveyance belt 3 so that the rotation axis direction is orthogonal to the traveling direction of the conveyance belt 3 and the conveyance belt 3 which conveys the base material (for example, non-tempered glass) 2 in a predetermined direction. And at least a doctor roll 5 in contact with the paint roll 4 at a predetermined pressing thickness. The coating solution 1 is supplied between the coating roll 4 and the doctor roll 5. The paint roll 4 and the doctor roll 5 are generally in contact with each other, but may rotate at the same speed or may rotate at different speeds.
In the figure, the arrow on the right of the substrate 2 points in the direction of transport of the substrate, and the arrow on the paint roll 4 and the arrow on the doctor roll 5 point in the direction of rotation of the respective roll.

Preferably, the operating conditions of the reverse roll coater are such that Vt (paint roll rotational speed) / Vb (substrate transfer speed) is 0.2 to 3.0. The ratio is more preferably 0.3 to 1.5, further preferably 0.4 to 1.2. In another embodiment, the ratio is 0.2-1.5, 0.2-1.2, 0.3-3.0, 0.3-1.2, 0.4-3.0, Or it may be 0.4 to 1.5.
By the Vt / Vb being 0.2 or more, the appearance of the substrate end can be kept good. When Vt / Vb is 3.0 or less, the coating liquid on the roll can be prevented from waving and the appearance of the coating can be improved.

Furthermore, it is preferable that Vb (base material conveyance speed) is 4-30 m / min from a viewpoint of productivity. Vb is more preferably 5 to 20 m / min, further preferably 5 to 15 m / min. In other embodiments, V b may be 4 to 20 m / min, 4 to 15 m / min, or 5 to 30 m / min. High productivity can be achieved by Vb (substrate conveyance speed) being 4 m / min or more. By setting Vb to 30 m / min or less, even when the viscosity of the coating liquid is high, the coating liquid on the roll can be prevented from waving and the appearance of the coating can be improved.
The relative speed (V) of the coating roll rotational speed (Vt) to the substrate transport speed (Vb) of the reverse roll coater is defined by the relative speed (V) = Vt (paint roll rotational speed) + Vb (substrate transport speed) Ru. The relative velocity (V) is preferably 4.8-120. The relative velocity (V) is more preferably 5.6 to 66. In other embodiments, the relative velocity (V) may be 4.8-66 or 5.6-120.

[Coating liquid]
Each component which comprises a coating liquid is demonstrated.
The coating liquid contains metal oxide particles (A), polymer particles (B) and at least one or more solvents (D).
The number average particle diameter (a mixture of primary particles and secondary particles, or only primary particles or secondary particles) of the metal oxide particles (A) may be preferably used. Is 1 nm to 200 nm, more preferably 1 nm to 100 nm. The number average particle diameter of the polymer particles (B) (may be a mixture of primary particles and secondary particles, or may be only primary particles or secondary particles) is preferably It is 10 nm to 300 nm, more preferably 10 nm to 200 nm. More preferably, the sum of the number average particle size of the metal oxide particles (A) and the number average particle size of the polymer particles (B) is 50 nm to 150 nm. Here, the number average particle diameter of metal oxide particle (A) and polymer particle (B) can be measured by the method as described in the Example mentioned later. Moreover, these number average particle diameters can be controlled to the above-mentioned range, for example, by the concentration of the raw material and the emulsifier. The number average particle size of the metal oxide particles (A) is a value in the coating solution, but it is considered that it is usually maintained in the formed antireflective film.
In one embodiment, the mass ratio (A) / (B) (solid content conversion) of the metal oxide particles (A) to the polymer particles (B) in the coating solution is 0.05 / 1 or more and 1/1. It is preferable that it is the following, More preferably, it is 0.05 / 1 or more and 0.5 / 1 or less, More preferably, it is 0.1 / 1 or more and 0.5 / 1 or less.

<Metal oxide particles (A)>
Although it does not specifically limit as a metal oxide particle (A), For example, oxides, such as silicon, aluminum, titanium, a zirconium, zinc, tin, indium, a gallium, germanium, antimony, molybdenum, are mentioned. Two or more of these metal oxides may be used in combination. Silicon oxide is particularly preferred in view of optical properties and durability.
The metal oxide particles (A) are used as a raw material of the coating liquid, for example, in the form of powder, dispersion, sol and the like. Here, in the dispersion or sol, the metal oxide particles (A) are contained in water and / or a hydrophilic organic solvent at a concentration of 0.01 to 80% by mass, preferably 0.1 to 50% by mass. It means dispersed as primary particles and / or secondary particles. Examples of hydrophilic organic solvents include alcohols such as ethylene glycol, butyl cellosolve, n-propanol, isopropanol, n-butanol, ethanol and methanol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and ethers such as tetrahydrofuran and dioxane. , Amides such as dimethylacetamide and dimethylformamide, dimethylsulfoxide, nitrobenzene, N-methylpyrrolidone and the like, and further, mixtures of two or more of these can be used.
Specific examples of silicon oxide particles include, but are not limited to, “Snowtex-OXS (registered trademark)” manufactured by Nissan Chemical Industries, Ltd., “Snowtex-O (registered trademark)” manufactured by the same. Examples include “Snowtex-OL (registered trademark)” and “Snowtex-OYL (registered trademark)” manufactured by the same company.

<Polymer particles (B)>
Examples of the polymer constituting the polymer particles (B) include, but are not limited to, polyurethane-based, polyester-based, poly (meth) acrylate-based, and poly (meth) acrylate-silicone copolymers, for example. Polyvinyl acetate type, polybutadiene type, polyvinyl chloride type, chlorinated polypropylene type, polyethylene type, polystyrene type, polystyrene- (meth) acrylate type copolymer, rosin type derivative, alcohol adduct of styrene-maleic anhydride copolymer And polymers composed of Two or more of these polymer particles (B) may be used in combination.

It is preferable to contain a hydrolysable silicon compound (b1) as a component which comprises polymer particle (B).
As the hydrolyzable silicon compound (b1), a compound represented by the formula: SiW _x R _y , a condensation product thereof, a silane coupling agent and the like can be used.
In the above formula: SiW _x R _y , W is an alkoxy group having 1 to 20 carbon atoms, a hydroxyl group, an acetoxy group having 1 to 20 carbon atoms, a halogen atom, a hydrogen atom, an oxime group having 1 to 20 carbon atoms, an enoxy group, an aminoxy And at least one group selected from an amido group. R represents a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, and an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms or a carbon number It represents at least one hydrocarbon group selected from an alkoxy group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms which is substituted with a halogen atom. x is an integer of 1 or more and 4 or less, and y is an integer of 0 or more and 3 or less. Also, x + y = 4.
The silane coupling agent means a compound having a functional group having reactivity with an organic substance such as a vinyl polymerizable group, an epoxy group, an amino group, a methacryl group, a mercapto group or an isocyanate group in the molecule.

Examples of the compound represented by the above formula: SiW _x R _y include, but are not limited to, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, and tetra-n. Tetraalkoxysilanes such as -butoxysilane; methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyl Triethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane Nyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-hydroxyethyltrimethoxysilane , 2-hydroxyethyltriethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3 Hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3- (meth) acryloxypropyltrimethoxy Silane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloyloxypropyltri n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysilane, Trialkoxysilanes such as 3-ureidopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, di-n-propyldimethoxysilane n-propyldiethoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane, di-n-butyldimethoxysilane, di-n-butyldiethoxysilane, di-n-pentyldimethoxysilane, di-n-pentyldiethoxysilane, Di-n-hexyldimethoxysilane, di-n-hexyldiethoxysilane, di-n-heptyldimethoxysilane, di-n-heptyldiethoxysilane, di-n-octyldimethoxysilane, di-n-octyldietone Dialkoxysilanes such as cis-silane, di-n-cyclohexyldimethoxysilane, di-n-cyclohexyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane; trimethylmethoxysilane, Monoalkoxysilanes such as trimethylethoxysilane can be mentioned.
The mass ratio of the hydrolyzable silicon compound (b1) in the polymerization stock solution for obtaining the polymer particles (B) is preferably 0.01 to 80 mass% from the viewpoint of polymerization stability, more preferably 0. It is 1 to 70% by mass.

As another component which comprises polymer particle (B), the reactive emulsifier which has a radically polymerizable double bond is mentioned. Although not limited to the following, for example, a vinyl compound having a sulfonic acid group or a sulfonate group, a vinyl compound having a sulfate ester group, an alkali metal salt or ammonium salt thereof; a vinyl compound having a nonionic group such as polyoxyethylene; Mention may be made of vinyl compounds having an ammonium salt.
Examples of salts of vinyl compounds having a sulfonic acid group or a sulfonate group include, but are not limited to, groups having a radically polymerizable double bond and being an ammonium salt, sodium salt or potassium salt of a sulfonic acid group, for example Alkyl group having 1 to 20 carbon atoms, alkyl ether group having 2 to 4 carbon atoms, polyalkyl ether group having 2 to 4 carbon atoms, aryl group having 6 or 10 carbon atoms, and succinic acid group partially substituted by A compound having a substituent selected from the group consisting of: a vinyl sulfonate compound having a vinyl group to which a group which is an ammonium salt, a sodium salt or a potassium salt of a sulfonic acid group is bonded.

The compound having a succinic acid group which is partially substituted by a group which is an ammonium salt, a sodium salt or a potassium salt of a sulfonic acid group as a reactive emulsifier is not limited to the following, for example, allyl Sulfosuccinate is mentioned. Moreover, as a commercial item, Eleminol JS-2 (trade name) (manufactured by Sanyo Kasei Co., Ltd.), Latemul S-120, S-180A or S-180 (trade name) (manufactured by Kao Corp.) can be mentioned. .
As a reactive emulsifier, an alkyl ether group having 2 to 4 carbon atoms or a polyalkyl ether group having 2 to 4 carbon atoms, which is partially substituted by a group that is an ammonium salt, sodium salt or potassium salt of sulfonic acid group As a compound which it has, although not limited to the following, for example, Aqualon HS-10 or KH-1025 (trade name) (Daiichi Kogyo Seiyaku Co., Ltd. product), Adekaria soap SE-1025N or SR-1025 (trade name) (Manufactured by Asahi Denka Kogyo Co., Ltd.).

  Examples of the vinyl compound having a nonionic group as a reactive emulsifier include, but are not limited to, α- [1-[(allyloxy) methyl] -2- (nonylphenoxy) ethyl] -ω-hydroxy. Polyoxyethylene (trade name: Adekaria soap NE-20, NE-30, NE-40, etc., manufactured by Asahi Denka Kogyo Co., Ltd.), polyoxyethylene alkyl propenyl phenyl ether (trade name: Aqualon RN-10, RN- 20, RN-30, RN-50, etc., manufactured by Daiichi Pharmaceutical Industry Co., Ltd.).

  The compounding amount of the reactive emulsifier described above in the polymer stock solution for obtaining the polymer particles (B) is preferably 10 parts by mass or less with respect to the total amount (100 parts by mass) of the polymer stock solution excluding the solvent, It is more preferable that the amount is equal to or more than .001 parts by mass and equal to or less than 5 parts by mass.

<Hydrolyzate of Hydrolyzable Silicon Compound (C)>
In one embodiment, the coating liquid is a hydrolyzate (or hydrolytic condensate) of the hydrolyzable silicon compound (C) in distinction from the hydrolyzable silicon compound used for the polymerization of the polymer particles (B). It can further include. This component can be used when the solvent (D) of the coating solution contains water. The hydrolysis is not particularly limited, and may be partial hydrolysis or total hydrolysis, but it is preferable to be total hydrolysis. The hydrolyzable silicon compound (C) is not particularly limited, but may be the same compound as the hydrolyzable silicon compound used for polymerizing the polymer particles (B). Two or more of these hydrolyzable silicon compounds (C) may be used in combination.
Examples of the hydrolyzable silicon compound (C) include, but are not limited to, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, etc. Tetraalkoxysilanes; methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, vinyltrime Xylsilane, vinyltriethoxysilane, allyltrimethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3, 3,3-Trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2- Hydroxyethyltriethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyl Triethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- Glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (Meth) atacyloxypropyltriethoxysilane, 3- (Meth) acryloyloxypropyltri n-propoxysilane, 3- (Meth) acryloyloxypropyltriisopropoxysilane, 3-ureido Examples include trialkoxysilanes such as ropirtrimethoxysilane and 3-ureidopropyltriethoxysilane.

  The mass ratio of the metal oxide particles (A) (in terms of solid content) to the hydrolyzable silicon compound (C) to be added to the coating solution is not particularly limited, but usually (C) / (A) = 100/100 to It may be 1000/100 and may typically be 200/100 to 800/100.

<Solvent (D)>
The solvent (D) is at least one or more solvents. Among them, when water is contained, it is preferably 3% by weight to 80% by weight, more preferably 4% by weight to 50% by weight, and still more preferably 5% by weight to 30% by weight. In another embodiment, the proportion of water is 3% to 50%, 3% to 30%, 4% to 80%, 4% to 30%, 5% by weight. It may be 80% by mass, or 5% by mass to 50% by mass. When the content of water is 3% by weight or more, the drying property is controlled to an appropriate range, and the variation of the solid content is small, and the control of the film thickness becomes easy. When the amount of water is 80% by mass or less, drying can be prevented from being excessively delayed, and productivity can be maintained.
Although it does not specifically limit as solvents other than water, For example, the hydrophilic organic solvent mentioned above in connection with metal oxide particle (A) is mentioned.

  The coating solution may further contain the following optional additive components. Non-limiting examples of additional additive components include, for example, light stabilizers, UV absorbers, thickeners, leveling agents, thixotropic agents, antifoam agents, freeze stabilizers, matting agents, crosslinking reactions Catalysts, pigments, curing catalysts, crosslinking agents, fillers, anti-skinning agents, dispersants, wetting agents, antioxidants, UV absorbers, rheology control agents, film forming aids, rust inhibitors, dyes, plasticizers, One or more of lubricants, reducing agents, preservatives, fungicides, deodorants, anti-yellowing agents, antistatic agents, charge control agents and the like can be mentioned. As these additive components, any of known ones may be used.

[Method of manufacturing laminate]
(First step)
<Preparation method of coating liquid>
In one embodiment, the coating liquid comprises the metal oxide particles (A) described above, the polymer particles (B), at least one or more solvents (D), and, if necessary, the hydrolyzable silicon compound (C) And other additive components can be obtained by mixing.
In general, when preparing a coating solution containing water, each component contained in the coating solution is diluted with water and then mixed, a method of mixing each component in water, and after mixing each component in advance, water And dilution methods. The mixing method may include, for example, a step of stirring at less than 40 ° C. for 10 minutes or more.

<Coating method by reverse roll coater>
The coating liquid can be applied on the substrate by the reverse roll coater described above to obtain a thin film. It is desirable to adjust the thickness of the thin film so that the film thickness of the void-containing layer described later falls within a preferable range.

The capillary number (Ca) calculated | required from (Formula 1) of a coating liquid is 0.1-80, Preferably it is 0.5-30, More preferably, it is 1-5. In other embodiments, the capillary number (Ca) may be 0.1-30, 0.1-5, 0.5-80, 0.5-5, 1-80 or 1-30. When the number of capillaries is 0.1 or more, sufficient film thickness control becomes possible, and when it is 80 or less, the coating liquid in the form of a roll is suppressed from being wavy, and a good appearance without film thickness unevenness is obtained. It will be possible to get.
The viscosity (25 ° C.) of the coating solution is preferably 1 to 10 mPa.s. s, more preferably 1 to 6 mPa. s, more preferably 1 to 4 mPa.s. s. Viscosity is 1 mPa. By being more than s, sufficient film thickness control becomes possible, and 10 mPa.s. By being less than or equal to s, it is possible to suppress the coating liquid from waving in a roll shape, and it is possible to obtain a good appearance without film thickness unevenness.
The surface tension (25 ° C.) of the coating solution is 15 to 45 mN / m, preferably 10 to 35 mN / m, and more preferably 18 to 28 mN / m. In other embodiments, the surface tension (25 ° C.) is 15 to 35 mN / m, 15 to 28 mN / m, 10 to 45 mN / m, 10 to 28 mN / m, 18 to 45 mN / m, or 18 to 35 mN / It may be m. When the surface tension is 15 mN / m or more, sufficient control of the film thickness becomes possible, and when 45 mN / m or less, it becomes easy to obtain a uniform coating film.
The capillary number (Ca) obtained from (Formula 1) of the coating liquid can be controlled by viscosity and surface tension when the relative velocity V is constant.
As a method of controlling surface tension, addition of an aprotic solvent, control by addition of an organic acid such as methanesulfonic acid, monovalent or divalent carboxyl group or sulfonic acid group as surface polar group of polymer particles (B), Control by introduction of a phosphate group, sulfobetaine group, etc. is possible. Examples of the aprotic solvent include, but are not limited to, acetone, acetonitrile, tetrahydrofuran, dimethyl sulfoxide, N, N-dimethylformamide and the like.

  By setting the ratio Vt / Vb of the coating roll rotation speed (Vt) to the substrate conveyance speed (Vb) of the reverse roll coater to 0.2 to 3.0, the number of capillaries is controlled, and the coating liquid can be made productive It can be applied uniformly. When the ratio Vt / Vb is 0.2 or more, the productivity of coating can be kept high. In addition, when the ratio Vt / Vb is 3.0 or less, the coating liquid on the roll can be prevented from being corrugated, and the occurrence of stripe film thickness unevenness can be prevented.

(Second step)
The solvent contained in the thin film is removed with a hot air of 300 ° C. or lower for the thin film obtained in the above (first step). It is preferable to remove substantially all the solvent by this step, and it is more preferable to remove all the solvent.
In the second step, the drying temperature for removing the solvent of the thin film is set to 300 ° C. or less. The drying temperature is preferably 10 to 120 ° C. or less, more preferably 18 to 60 ° C. or less. In other embodiments, the drying temperature may be 10-300 ° C. or less, 10-60 ° C. or less, 18-300 ° C. or less, or 18-120 ° C. or less. By drying at 300 ° C. or lower in this step, a dense coating composition layer is formed, and the appearance tends to be good. Moreover, it exists in the tendency to be excellent in productivity by drying above 10 degreeC.
This process may use any of the known hot air delivery machines. The temperature of the hot air can be measured by using a thermometer in the immediate vicinity of the hot air delivery port. Moreover, you may use the thing of several temperature 300 degrees C or less in a predetermined period as a warm air in this process.

(Third step)
In the third step in the present embodiment, the polymer particles (B) contained in the thin film are fired and removed at a temperature of 500 to 800 ° C., and an antireflection layer which is a void containing layer is provided on the substrate. Form a laminate. It is preferable to remove substantially all the polymer particles (B) by this process, and it is more preferable to remove all the polymer particles (B).
The temperature is preferably 600 to 800 ° C, and more preferably 650 to 800 ° C. In other embodiments, the temperature may be 500-750 ° C, 600-750 ° C, or 650-750 ° C. When the firing is performed at 500 ° C. or higher, voids are uniformly formed, and sufficient antireflection performance can be obtained. By baking at 800 ° C. or less, reduction of the formed voids due to shrinkage can be suppressed, and sufficient antireflection performance can be maintained.
Any known baking means may be used in this step. Although it does not specifically limit, baking can bake in an electric furnace, for example. Moreover, you may use several temperature of the range of 500-800 degreeC in a predetermined period as a calcination temperature of this process.

[Laminate]
In one embodiment, the laminate is obtained through the above-described (first step) to (third step).
The laminate comprises a substrate and an antireflective layer which is a void-containing layer formed on at least one side of the substrate.

(Film thickness of laminate)
In one embodiment, the thickness of the void-containing layer of the laminate is preferably 50 nm or more and 1000 nm or less, more preferably 80 nm or more and 200 nm or less, and more preferably 80 nm or more, from the viewpoint of causing sufficient antireflection performance. More preferably, it is 150 nm or less. In another embodiment, the thickness of the void-containing layer may be 50 nm or more and 200 nm or less, 50 nm or more and 150 nm or less, or 80 nm or more and 1000 nm or less. When the film thickness is 50 nm or more, the strength of the void-containing layer tends to be sufficiently maintained, and when the film thickness is 1000 nm or less, a laminate having uniform antireflection performance tends to be obtained.

  In order to obtain a laminate having a film thickness in the above range, the concentration of the solid content of the coating liquid for forming the void-containing layer may be adjusted. The solid content concentration of the coating liquid is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass, and still more preferably 1 to 6% by mass. In another embodiment, the solid content concentration of the coating liquid is 0.1 to 7% by mass, 0.1 to 6% by mass, 0.5 to 10% by mass, 0.5 to 6% by mass, or 1 to 10%. %, Or 1 to 7% by mass.

Moreover, it is also possible to adjust the film thickness of a space | gap content layer by adjusting the base-material conveyance speed of a roll coater, and a coating roll rotational speed.
The film thickness of the void-containing layer is measured by electron microscopic observation of a cross section (average of five randomly selected values) or reflection due to interference of the void-containing layer with an optical ellipsometer or reflection spectrophotometer. It can be determined by calculation using measured values of light. In the latter case, the calculated value is regarded as the average film thickness.

[Use of laminate]
The above-mentioned laminate can be suitably used as a laminate used for a long time outdoors, such as a solar cell, a mirror for solar thermal power generation, a building material, an automobile, etc., because it is excellent in anti-reflection performance. It does not mean that

Hereinafter, the present invention will be more specifically described with reference to specific examples and comparative examples, but the present invention is not limited to the following examples and comparative examples.
Various physical properties and evaluations in synthesis examples, examples and comparative examples described later were measured and evaluated by the following methods.

(1) Measurement of Number Average Particle Size The number average particle size of metal oxide particles (A) and polymer particles (B) using a dynamic light scattering type particle size distribution measuring apparatus UPA-UZ152 (manufactured by Nikkiso Co., Ltd.) Was evaluated.

(2) Measurement of total light transmittance About the test plate of the laminated body manufactured by the Example and comparative example mentioned later, the total light transmittance of 380-1100 nm was measured using spectral transmittance meter ST-100 made from AOPTEK.
When the total light transmittance was 1.5% or more relative to the total light transmittance of the test plate (glass) having no void containing layer, it was judged to have anti-reflection performance.

(3) Measurement of Viscosity The viscosity of the coating liquid was measured under an environment of 25 ° C. using a tuning fork type vibration viscometer (SV-10 manufactured by A & D Co., Ltd.).

(4) Measurement of Surface Tension The surface tension of the coating solution was measured under a 25 ° C. environment using a surface tension meter (DY-500 manufactured by Kyowa Interface Science Co., Ltd.).

(5) Coating film appearance The appearance of the laminate was visually observed in light of a fluorescent lamp to evaluate the change in stripe-like (or band-like) color originating in the film thickness unevenness. The stripe-like color change means that, for example, the purple part and the green part can be visually observed in the form of stripes (or bands) because the film thickness is different.
○: good appearance (no streaks of color change and the entire surface of the laminate has uniform color)
Δ: The appearance is almost good (very fine streaks of color change are observed)
X: appearance abnormality (striped color change is clearly observed)

Synthesis Example
Below, the synthesis example of the polymer particle (B) used in the Example and comparative example which are mentioned later is described.

Synthesis Example 1 Synthesis of Polymer Particles (B-1) Aqueous Dispersion In a reactor having a reflux condenser, a dropping tank, a thermometer and a stirrer, 1600 g of ion exchanged water and 7 g of dodecylbenzenesulfonic acid were charged. Thereafter, the mixture was heated to 80 ° C. with stirring to obtain a mixture (1).
As a raw material of the core layer, 130 g of dimethyldimethoxysilane and 100 g of phenyltrimethoxysilane were mixed to obtain a liquid mixture (2). The mixture (2) was added dropwise to the above mixture (1) over about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C. to obtain a mixture (3).
Thereafter, the mixture (3) was stirred for about 1 hour at a temperature of 80 ° C. in the reaction vessel.
Next, 130 g of butyl acrylate, 200 g of tetraethoxysilane, 100 g of phenyltrimethoxysilane, and 10 g of 3-methacryloxypropyltrimethoxysilane were mixed as a raw material for the shell layer to obtain a liquid mixture (4). In addition, 140 g of diethyl acrylamide, 3 g of acrylic acid, 13 g of a reactive emulsifier (trade name "Adecaria soap SR-1025", made by Asahi Denka Co., Ltd., 25 mass% solid content aqueous solution), 40 g of a 2 mass% aqueous solution of ammonium persulfate, And 1900 g of deionized water were mixed to obtain a liquid mixture (5). The mixture (4) and the mixture (5) are simultaneously added dropwise to the mixture (3) over about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C. Obtained.
Furthermore, as heat curing, the mixture (6) was stirred for about 2 hours at a temperature of 80 ° C. in the reaction vessel. Thereafter, 400 g of tetraethoxysilane was added dropwise to the mixture (6) over about 30 minutes while maintaining the temperature in the reaction vessel at 80 ° C. to obtain a mixture (7).
Furthermore, as heat curing, the mixture (7) was stirred for about 2 hours at a temperature of 80 ° C. in the reaction vessel. Thereafter, the mixture (7) is cooled to room temperature, filtered through a 100 mesh wire mesh, and the concentration is adjusted with purified water to obtain an aqueous dispersion of polymer particles (B-1) having a number average particle diameter of 90 nm (solid content 10 Mass%) was obtained.

Example 1
An aqueous dispersion of the polymer emulsion particles (B-1) synthesized in the above (Synthesis example 1) was used as the polymer particles (B).
As a raw material of the spherical silica fine particles (A), water-dispersed colloidal silica having an average particle diameter of 5 nm (trade name "Snowtex OXS" manufactured by Nissan Chemical Industries, Ltd., solid content 10% by mass) was used.
Tetraethoxysilane (Shin-Etsu Chemical Co., Ltd. product) was used as a hydrolysable silicon compound (C).
Add fine particles of silica (A), polymer particles (B) and hydrolyzable silicon compound (C) to water so that the solid content mass ratio (A) / (B) / (C) described in Table 1 can be obtained at room temperature. The mixture was stirred for 3 hours to hydrolyze the hydrolyzable silicon compound (C). Thereafter, dimethylsulfoxide and ethanol were added to adjust the amount of water in the coating solution to be 50% by mass and dimethylsulfoxide to be 3% by mass, and the mixture was stirred to obtain a coating solution having a solid content of 3% by mass.

  The above coating composition is applied to the smooth surface side of a substrate (10 cm × 10 cm white plate embossed glass: Solite manufactured by Asahi Glass, total light transmittance 91.7%) with a reverse roll coater (reverse roll coater manufactured by Tokyo Roller Co., Ltd.) After drying, it was dried with warm air at 20 ° C for 1 minute to obtain a test plate having a thin film (F-1), and then fired for 3 minutes at 700 ° C in an electric furnace and quenched after quenching. The test board (G-1) of the laminated body which has a space | gap content layer was obtained. The film thickness of the void-containing layer here is an average of five values randomly selected by electron microscope observation of the cross section.

At this time, the composition ratio in the thin film (F-1) is substantially equal to (A) / (B) / (C ′) = 15, similarly to the mass ratio of each component calculated in terms of solid content in the coating liquid. It is considered to be / 100/60.
Here, (A) is the mass ratio of the silica fine particles (A) in the thin film (F-1) obtained after the above drying, and (B) is the thin film (F-1) obtained after the above drying The mass ratio of polymer particles (B) in the mixture, and (C ′) is the hydrolysis condensate (C ′) of the hydrolyzable silicon compound (C) in the thin film (F-1) obtained after the above drying Mass ratio of
The evaluation results of the test plate (G-1) of the obtained laminate are shown in Table 1.
"Roll speed Vt" in Table 1 means the rotation speed of the coating roll of a reverse roll coater.

[Examples 2 to 3, Comparative Examples 1 to 4]
The composition ratio in the coating solution and the production conditions were changed as shown in Table 1, and a test plate of a laminate was obtained in the same manner as in [Example 1].
The evaluation results of the test plate of the obtained laminate are shown in Table 1.

  As shown in Table 1, it was found that the test plates of the laminates in Examples 1 to 3 have excellent appearance and antireflection performance.

  On the other hand, the test plates of the laminates in Comparative Examples 1 to 4 were inferior in appearance and the antireflective performance was not sufficient.

  All quantities, percentages or proportions used in the present specification and claims, and all numbers representing other numerical values, are to be understood in all cases as being modified by the term "about". is there. Accordingly, the numerical parameters set forth in the specification and appended claims are approximations that may vary depending upon the desired properties sought to be obtained.

  Since the laminate obtained by the manufacturing method of the present invention is excellent in appearance and reflection preventing property, it is suitably used as a member for which the reflection preventing performance of a solar cell, a solar power generation mirror, a building material, an automobile, etc. it can.

1: Coating liquid 2: Substrate (for example, untempered glass)
3: Conveying belt 4: Paint roll 5: Doctor roll

Claims (8)

A method of producing a laminate having an antireflective film on at least one side of a substrate, the method comprising
A coating liquid containing metal oxide particles (A), polymer particles (B), and at least one or more solvents (D) is applied to at least one surface of a substrate by a reverse roll coater to form a thin film Process,
The second step of removing the solvent with a hot air of 300 ° C. or less, and the third step of firing at a temperature of 500 to 800 ° C. to form a void, thereby forming an antireflective film,
(Formula 1): Ca = μV / σ (where, μ: viscosity of coating solution, σ: surface tension, V: relative speed of coating roll rotation speed (Vt) of reverse roll coater to substrate transport speed (Vb) The capillary number Ca calculated by the equation is 1 to 80,
Method of manufacturing a laminate.   The coating solution is a metal oxide particle (A) having a number average particle diameter of 1 nm to 200 nm, a polymer particle (B) having a number average particle diameter of 10 nm to 300 nm, and a hydrolyzate of a hydrolyzable silicon compound (C). And 3% by weight to 80% by weight of water as a solvent (D), the method for producing a laminate according to claim 1.   The viscosity of the coating solution is 1 to 10 mPa.s. The method for producing a laminate according to claim 1 or 2, wherein s and surface tension are 15 to 45 mN / m.   The ratio Vt / Vb of the coating roll rotation speed (Vt) to the base material transfer speed (Vb) of the reverse roll coater is 0.2 to 3.0. Method of producing a laminate.   The laminated body which has an anti-reflective film manufactured by the manufacturing method of the laminated body as described in any one of Claim 1 thru | or 4.   The cover glass for solar cells containing the laminated body of Claim 5.   A solar power generation mirror comprising the laminate according to claim 5. The glass for building materials containing the laminated body of Claim 5.