JP2016085239A - Coating composition and method of manufacturing optical coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition which allows for forming a film having even thickness even on an irregular surface and being capable of maintaining a superior anti-reflection property even in a high-humidity environment and offers superior production stability.SOLUTION: A coating composition for forming an optical film contains a metal oxide (A) and polymer emulsion particles (B) and has a TI value in a range of 2-10.SELECTED DRAWING: None

Description

  The present invention relates to a coating composition and a method for producing an optical coating film.

Conventionally, many of the antireflection films, which are optical coating films, are manufactured by a first process for forming a coating film and a second process for forming voids in the coating film. Thus, after forming a coating film, the antireflection film reduces the refractive index of the coating film and decreases the reflectance by forming voids in the coating film.

For example, Patent Documents 1 to 4 disclose a porous body in which voids are introduced into a coating film using a pore-causing agent.

Further, in Patent Documents 5 to 7, as a method of forming a low refractive index porous body that does not require extraction of the porous material from the coating film, a porous coating solution containing a chain metal oxide is used. A method for depositing a body is disclosed.

Further, Patent Documents 8 and 10 disclose an antireflection film having excellent scratch resistance obtained by using a coating liquid containing a chain silica sol and spherical fine particles.

Furthermore, in Patent Document 9, an aqueous polymer dispersion excellent in mechanical strength, transparency, weather resistance, chemical resistance, optical properties, antifouling property, antifogging property, antistatic property and the like was used. A coating is disclosed.

Furthermore, Patent Document 11 describes a coating composition having excellent antifouling performance.

Japanese Unexamined Patent Publication No. 01-31501 Japanese Patent Laid-Open No. 07-140303 Japanese Patent Laid-Open No. 03-199043 JP-A-11-035313 JP 2001-188104 A Japanese Patent Laid-Open No. 11-061043 JP 11-292568 A JP 2005-10470 A International Publication No. 2007/069596 Pamphlet Special table 2011-530401 gazette International Publication No. 2010/104146 Pamphlet

  However, the techniques disclosed in Patent Documents 1 to 11 have a problem in that there is room for improvement in antireflection characteristics because the film thickness becomes non-uniform when applied to an uneven substrate. .

  In view of the above-described problems of the prior art, an object of the present invention is to provide a coating composition that can form a uniform film thickness on an uneven substrate.

As a result of intensive studies to solve the above problems, the present inventors are excellent in conformity to irregularities by coating a coating composition having a thixotropic index (TI value) of 2 to 10 on an irregular substrate. It discovered that an optical coating film was obtained and came to complete this invention.
That is, the present invention is as follows.

[1]
A coating composition comprising a metal oxide (A) and polymer emulsion particles (B), wherein the coating composition has a TI value of 2 to 10, wherein the coating composition is for an optical coating film.
[2]
The coating composition for optical coatings as described in [1] above, wherein the solid content concentration of the coating composition is 6% and the TI value is 2 to 10.
[3]
[1] or [2], wherein the ratio of the particle size (rA) of the metal oxide (A) to the particle size (rB) of the polymer emulsion particles (B) is rA <rB and rB <100 nm. ] Coating composition for optical coating films as described in any one of the above.
[4]
Applying the coating composition for an optical coating film according to any one of [1] to [3] and drying the precursor of the optical coating film formed at a temperature of 500 ° C. or higher. An optical coating film formed by.
[5]
Applying the coating composition for an optical coating film according to any one of the above [1] to [3] and drying to form a precursor of the optical coating film; And a step of sintering at a temperature to form an optical coating film.
[6]
At least the average value of the major axis (L) and the maximum value (D) of the minor axis perpendicular to the major axis (L): (void size = (L + D) / 2) has a void (X) of 20 nm or more, and the void (X) The major axis (L) and the minor axis (D) are 1 <L / D, and the gap (X) is not in contact with the substrate at the interface with the substrate. Optical coating.
[7]
The optical coating film according to [6], further including a void (Y) having a void size of less than 20 nm around the void (X).
[8]
The antireflection film comprised from the optical coating film as described in any one of said [4], [6], or [7].
[9]
The glass for solar cells containing the antireflection film as described in said [8].
[10]
A solar cell module comprising the antireflection film according to [8].
[11]
The condensing lens for solar cells containing the antireflection film as described in said [8].
[12]
A solar power generation mirror including the antireflection film according to [8].
[13]
The condensing glass tube for solar power generation containing the antireflection film as described in said [8].

  According to the present invention, an optical coating film that can form a uniform film thickness even on an uneven substrate, can maintain excellent antireflection characteristics even in a humid environment, and has excellent production stability can be obtained.

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The following embodiments are examples 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 within the scope of the gist.

(Base material)
Although the base material used by this embodiment is not specifically limited, For example, a plate form, a sheet form, and a film form are mentioned.
The substrate used also in the present embodiment may have a smooth surface or may have irregularities with a predetermined height difference on the surface.
For example, the base material which has the unevenness | corrugation of 0.1-100 micrometers in elevation on the surface of a base material from a viewpoint of improving the light transmittance of a base material is preferable.
The height difference of the irregularities is preferably 0.1 to 100 μm, more preferably 1 to 60 μm, and further preferably 5 to 40 μm. The surface roughness (Ra) is preferably from 0.1 to 10 μm, more preferably from 0.3 to 5 μm, still more preferably from 0.5 to 2 μm.
When the unevenness level is within the above range, the permeability tends to be superior.

Although the material of a base material is not specifically limited, For example, glass and resin are mentioned.
In particular, glass is preferable from the viewpoints of transparency and weather resistance.
Examples of the glass include, but are not limited to, general glass, tempered glass, laminated glass, multilayer glass, chemically tempered glass, and the like. These may be used depending on the purpose. it can.
Examples of the resin include, but are not limited to, an acrylic resin, a polycarbonate resin, a cyclic polyolefin resin, a polyethylene terephthalate resin, and an ethylene-fluoroethylene copolymer.
These resins may be further kneaded with a weathering agent such as an ultraviolet absorber for the purpose of imparting weatherability.
As the substrate, a substrate having a thickness of 5 mm or less, more preferably 2 mm or less is preferable from the viewpoint of cost.

(Coating composition for optical coating film)
The composition for optical coating films of this embodiment has thixotropic properties (or thixotropic properties). Thixotropy refers to the property of changing viscosity by mechanical stimulation such as stirring. Here, the thixotropic index (TI value) is a ratio of the viscosity (Z1) at a rotor rotational speed of 60 rpm and the viscosity (Z2) at a rotor rotational speed of 6 rpm using a B-type viscometer in an environment of 25 ° C. say. That is, TI value = Z2 / Z1.
If the substrate has irregularities, the composition tends to be unevenly distributed in the indented portion, resulting in a non-uniform film thickness and decreased optical properties such as appearance and antireflection, so that the unevenness of the substrate follows and is uniform. From the viewpoint of forming an optical coating film having a thickness, the TI value is preferably 2 to 10. More preferably, it is 3-9, More preferably, it is 4-7.
When the TI value is less than 2, the coating composition may be unevenly distributed in the recesses of the substrate. When the TI value exceeds 10, coating unevenness occurs and the appearance of the coating film is inferior.
The coating composition for an optical coating film contains a metal oxide (A) and polymer emulsion particles (B).

<Metal oxide (A)>
The metal oxide (A) is not particularly limited as the metal oxide (a1), and examples thereof include silicon, aluminum, titanium, zirconium, zinc, tin, indium, gallium, germanium, antimony, molybdenum, and tungsten. An oxide is mentioned.
The average particle diameter of the spherical metal oxide (a1) is preferably 1 to 100 nm, more preferably 1 to 50 nm, and further preferably 1 to 10 nm from the viewpoint of film thickness uniformity. Here, the average particle diameter of the spherical metal oxide (a1) is the primary particle diameter when the particles are present in the form of primary particles, and is aggregated when the particles are present in the form of aggregated particles. It refers to the particle diameter (secondary particle diameter) and can be determined by the following method. That is, the particle diameter (biaxial average) of the corresponding particles present in a transmission microscope (TEM) photograph taken by adjusting so that 100 to 200 spherical metal oxide (a1) particles are captured. It can be determined by measuring the diameter, that is, the average value of the minor axis and the major axis, and determining the average value of the measured particle diameters.

In the optical coating film of this embodiment, it is preferable that the coating composition further includes a hydrolyzable silicon compound (C).
By including the hydrolyzable silicon compound (C) in the coating composition, the hydrolyzable silicon compound (C) can be permeated into the voids (Y) having an average void size of less than 20 nm. The average void size of (Y) can be controlled.
In the coating composition, when the hydrolyzable silicon compound (C) is contained, the condensation reaction between the silanol group of the hydrolyzable silicon compound (C) and the hydroxyl group present on the surface of the metal oxide (A) As a result, a bond is formed, or a hydrogen bond is formed between the hydrolyzable silicon compound (C) and the metal oxide (A). Thereby, the mechanical strength of the coating film obtained from the coating composition is further increased. The hydrolyzable silicon compound (C) will be described later.

The coating composition for forming the optical coating film of the present embodiment includes the metal oxide (a
In addition to 1), other metal oxides made of, for example, boron, phosphorus, silicon, aluminum, titanium, zirconium, zinc, tin, indium, gallium, germanium, antimony, molybdenum and the like may be included.

<Polymer emulsion particles (B)>
The polymer emulsion particles (B) contained in the coating composition of the present embodiment indicate thixotropic properties due to the interaction with the metal oxide (A) and / or the hydrolyzable silicon compound (C). It is an emulsion. The polymer emulsion particles (B) are composed of a predetermined polymer. Examples of the polymer include, but are not limited to, polyurethane, polyester, poly (meth) acrylate, poly (meth) acrylate-silicone copolymer, polyvinyl acetate, polybutadiene, Polymers composed of polyvinyl chloride, chlorinated polypropylene, polyethylene, polystyrene, polystyrene- (meth) acrylate copolymers, rosin derivatives, alcohol adducts of styrene-maleic anhydride copolymers, etc. Etc.

From the viewpoint of thixotropy, the polymer emulsion particles (B) are polymerized with a hydrolyzable silicon compound (b1) and / or a vinyl monomer (b2) having a secondary and / or tertiary amide group. It is preferable to include as a body.
The polymer emulsion particles (B) are obtained by polymerizing the above (b1) and (b2), (b1
), (B2) may be either a mixture or a composite of those polymerized, or a combination thereof.

In addition, the number average particle diameter of polymer emulsion particle | grains (B) can be measured by the method described in the below-mentioned Example.
The hydrolyzable silicon compound (b1) used in the production of the polymer emulsion particles (B) is not limited to the following, but for example, a compound represented by the following formula (1) or a condensation product thereof Products, silane coupling agents and the like.

SiWxRy (1)
(In the formula (1), W represents 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 group, R represents at least one group selected from the group consisting of amide groups, wherein R represents a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, and a substituted group. Or at least one hydrocarbon group selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms 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, and x + y = 4.

The silane coupling agent which is an example of the hydrolyzable silicon compound (b1) is a functional group having reactivity with organic substances such as a vinyl polymerizable group, an epoxy group, an amino group, a methacryl group, a mercapto group, and an isocyanate group. Is a hydrolyzable silicon compound present in the molecule.

Examples of the hydrolyzable silicon compound (b1) include, but are not limited to, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, and tetra-n-butoxysilane. Tetraalkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane,
Ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane , Phenyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysila , 3,3,3-trifluoropropyl triethoxysilane,
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) acryloxypropyltrimethoxysilane, 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-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-octyldiethoxysilane, di-n-cyclohexyldimethoxysilane, di-n-
Examples include dialkoxysilanes such as cyclohexyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and 3- (meth) acryloyloxypropylmethyldimethoxysilane; monoalkoxysilanes such as trimethylmethoxysilane and trimethylethoxysilane.

Further, these hydrolyzable silicon compounds (b1) may be used alone as one type,
Two or more kinds may be mixed and used.

The hydrolyzable silicon compound (b1) may be used as a condensation product. In such a case, the weight average molecular weight in terms of polystyrene by GPC measurement of the condensation product is preferably 200 to 5.
000, more preferably 300-1000.

Among the hydrolyzable silicon compounds (b1) described above, a silicon alkoxide having a phenyl group,
For example, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane and the like are preferable because of excellent polymerization stability in the presence of water and an emulsifier.

Among the hydrolyzable silicon compounds (b1), 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane,
3- (meth) acryloyloxypropylmethyldimethoxysilane, 3- (meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyl Silane coupling agents having vinyl polymerizable groups such as trimethoxysilane and 2-trimethoxysilylethyl vinyl ether, and silane coupling agents having thiol groups such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane Can form a chemical bond by copolymerization or chain transfer reaction with the above-mentioned vinyl monomer (b2) having a secondary and / or tertiary amide group.

The use amount of the hydrolyzable silicon compound (b1) is preferably in the range of 0.001 to 0.95 as the mass ratio (b1) / (B) to the polymer emulsion particles (B) to be obtained.
The mass of the polymer emulsion particles (B) is the above-mentioned vinyl monomer (b2) having secondary and / or tertiary amide groups, and other vinyl monomers (b3) copolymerizable therewith. ,
Furthermore, it shall be the mass of the polymerization product obtained when all the hydrolyzable silicon compounds (b1) are polymerized.

The vinyl monomer (b2) having a secondary and / or tertiary amide group used for producing the polymer emulsion particles (B) is not limited to the following, for example, N- Methylacrylamide, N-methylmethacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-
Diethylacrylamide, N-ethylmethacrylamide, N-methyl-N-ethylacrylamide, N-methyl-N-ethylmethacrylamide, N-isopropylacrylamide, Nn-propylacrylamide, N-isopropylmethacrylamide, Nn
-Propylmethacrylamide, N-methyl-Nn-propylacrylamide, N-methyl-N-isopropylacrylamide, N-acryloylpyrrolidine, N-methacryloylpyrrolidine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylhexahydro Azepine, N-acryloylmorpholine, N-methacryloylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, N, N′-methylenebisacrylamide, N, N′-methylenebismethacrylamide, N-vinylacetamide,
Examples include diacetone acrylamide, diacetone methacrylamide, N-methylol acrylamide, and N-methylol methacrylamide.

The other vinyl monomer (b3) copolymerizable with the vinyl monomer (b2) having a secondary and / or tertiary amide group is not limited to the following. )
Functionality such as acrylic ester, aromatic vinyl compound, vinyl cyanide compound, carboxyl group-containing vinyl monomer, hydroxyl group-containing vinyl monomer, epoxy group-containing vinyl monomer, carbonyl group-containing vinyl monomer And monomers containing a group.

Examples of the (meth) acrylic acid ester include, but are not limited to, for example, a (meth) acrylic acid alkyl ester having 1 to 50 carbon atoms in the alkyl part, and an ethylene oxide group having 1 to 100 carbon atoms. (Poly) oxyethylene di (meth) acrylate etc. are mentioned.
Examples of the (meth) acrylic acid alkyl ester having 1 to 50 carbon atoms in the alkyl part include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and (meth) acrylic acid. Examples include 2-ethylhexyl, methyl cyclohexyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate, and the like.
Examples of the (poly) oxyethylene di (meth) acrylate having 1 to 100 ethylene oxide groups include, but are not limited to, ethylene glycol di (meth) acrylate and di (meth) acrylic. Examples include diethylene glycol acid, diethylene glycol methoxy (meth) acrylate, and tetraethylene glycol di (meth) acrylate.

In the present specification, (meth) acrylic is a simple description of methacrylic or acrylic.

The amount of the (meth) acrylic acid ester used (when using a plurality of (meth) acrylic acid esters, the total amount) is preferably in the total vinyl monomer constituting the polymer emulsion particles (B). It is 0-99.9 mass%, More preferably, it is 5-80 mass%, More preferably, it is 20-50 mass%.

The aromatic vinyl compound as the vinyl monomer (b3) is not particularly limited, and examples thereof include styrene and vinyl toluene.
The aromatic vinyl compound is preferably 0 to 99.9% by mass, and more preferably 5 to 80% by mass in the total vinyl monomers constituting the polymer emulsion particles (B).

The vinyl cyanide compound as the vinyl monomer (b3) is not particularly limited, and examples thereof include acrylonitrile and methacrylonitrile.
The vinyl cyanide compound is preferably 0 to 99.9% by mass, and more preferably 5 to 80% by mass in the total vinyl monomers constituting the polymer emulsion particles (B).

The carboxyl group-containing vinyl monomer as the vinyl monomer (b3) is not particularly limited. For example, (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, anhydrous Mention may be made of maleic acid or half esters of dibasic acids such as itaconic acid and maleic acid. By using these carboxylic acid group-containing vinyl monomers, carboxyl groups can be introduced into the polymer emulsion particles (B), and electrostatic repulsion can be provided between the polymer emulsion particles. It is possible to improve the stability as an emulsion and to provide resistance to an external dispersion breaking action such as agglomeration during stirring. At this time, in order to further improve the electrostatic repulsion force, the introduced carboxyl group is partially or completely neutralized with amines such as ammonia, triethylamine and dimethylethanolamine, and bases such as NaOH and KOH. Also good.

The amount of the carboxyl group-containing vinyl monomer used (when a plurality of carboxyl group-containing vinyl monomers are used, the total amount thereof) is the total vinyl monomers (B) constituting the polymer emulsion particles (B). In (b2) + (b3)), 0 to 50% by mass is preferable from the viewpoint of water resistance. More preferably, it is 0.1-10 mass%, More preferably, it is 0.1-5 mass%
It is.

The hydroxyl group-containing vinyl monomer as the vinyl monomer (b3) is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3- Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-
Hydroxyalkyl esters of (meth) acrylic acid such as hydroxybutyl (meth) acrylate; hydroxyalkyl esters of fumaric acid such as di-2-hydroxyethyl fumarate and mono-2-hydroxyethyl monobutyl fumarate; allyl alcohol and ethylene oxide (Poly) oxyethylene mono (meth) acrylate having 1 to 100 groups; (Poly) oxypropylene mono (meth) acrylate having 1 to 100 propylene oxide groups; Monomer "(trade name of caprolactone addition monomer manufactured by Daicel Chemical Industries, Ltd.) and other hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acid.

When a hydroxyl group-containing vinyl monomer is used as the vinyl monomer (b3), a metal oxide (
It becomes easy to control the hydrogen bonding force between A) and the vinyl monomer (b2) having a secondary and / or tertiary amide group, and the water dispersion stability of the polymer emulsion particles (B) is improved. It becomes possible to make it.

The amount of the hydroxyl group-containing vinyl monomer used is preferably 0 to 80% by mass, more preferably 0.1 to 50% by mass, and more preferably 0.1 to 50% by mass in the total vinyl monomers constituting the polymer emulsion particles (B). Preferably it is 0.1-10 mass%.

Examples of the epoxy group-containing vinyl monomer as the vinyl monomer (b3) include, but are not limited to, glycidyl group-containing vinyl monomers. Examples of the glycidyl group-containing vinyl monomer include glycidyl (meth) acrylate, allyl glycidyl ether, and allyl dimethyl glycidyl ether.

Examples of the carbonyl-containing vinyl monomer as the vinyl monomer (b3) include, but are not limited to, diacetone acrylamide.

When the glycidyl group-containing vinyl monomer or the carbonyl group-containing vinyl monomer is used as the vinyl monomer (b3), the polymer emulsion particles (B) become reactive, and a hydrazine derivative, By crosslinking with a carboxylic acid derivative, an isocyanate derivative, or the like, it is possible to form a coating film having excellent solvent resistance. The amount of glycidyl group-containing vinyl monomer or carbonyl group-containing vinyl monomer used is determined by polymer emulsion particles (B).
Is preferably 0 to 50% by mass in the total vinyl monomers constituting

An emulsifier may be used in the synthesis of the polymer emulsion particles (B).
Examples of the emulsifier include, but are not limited to, alkylbenzenesulfonic acid, alkylsulfonic acid, alkylsulfosuccinic acid, polyoxyethylene alkylsulfuric acid, polyoxyethylenealkylarylsulfuric acid, polyoxyethylene distyrylphenyl ether sulfonic acid. Acidic emulsifiers such as alkali metal (Li, Na, K, etc.) salts of acidic emulsifiers,
Anionic surfactants such as ammonium salts of acidic emulsifiers, fatty acid soaps; quaternary ammonium salts such as alkyltrimethylammonium bromide, alkylpyridinium bromide, imidazolinium laurate, pyridinium salts, imidazolinium salt type cationic surfactants Agent: Nonionic surfactant such as polyoxyethylene alkyl aryl ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene oxypropylene block copolymer, polyoxyethylene distyryl phenyl ether, and reactivity having radical polymerizable double bond And emulsifiers.

Among these emulsifiers, when a reactive emulsifier having a radical polymerizable double bond is selected, the water dispersion stability of the polymer emulsion particles (B) is further improved, and water resistance, chemical resistance, It is more preferable because a coating film excellent in optical characteristics, strength, and the like can be formed.

Examples of the reactive emulsifier having a radical polymerizable double bond include, but are not limited to, a vinyl monomer having a sulfonic acid group or a sulfonate group, and a vinyl monomer having a sulfate group. And alkali metal salts or ammonium salts thereof; vinyl monomers having a nonionic group such as polyoxyethylene; vinyl monomers having a quaternary ammonium salt;

The salt of a vinyl monomer having a sulfonic acid group or a sulfonate group as the reactive emulsifier is not limited to the following. For example, the reactive emulsifier has a radically polymerizable double bond and has a sulfonic acid group. Alkyl group having 1 to 20 carbon atoms, alkyl ether group having 2 to 4 carbon atoms, and 2 to 2 carbon atoms partially substituted by a group that is an ammonium salt, sodium salt or potassium salt
A compound having a substituent selected from the group consisting of 4 polyalkyl ether groups, aryl groups having 6 or 10 carbon atoms and succinic acid groups; and a group which is an ammonium salt, sodium salt or potassium salt of a sulfonic acid group And vinyl sulfonate compounds having a vinyl group.

The compound having a succinic acid group partially substituted with a group that is an ammonium salt, sodium salt or potassium salt of the sulfonic acid group is not limited to the following, but examples include allylsulfosuccinate. Can be mentioned. These can also use a commercial item, and it is not specifically limited, For example, Eleminol JS-2 (brand name) (made by Sanyo Kasei Co., Ltd.), Latemuru S-120, S-180A, or S-180 (brand name) (Manufactured by Kao Corporation).

As a compound having 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 which is an ammonium salt, sodium salt or potassium salt of a sulfonic acid group, For example, but not limited to Aqualon HS
-10 or KH-1025 (trade name) (Daiichi Kogyo Seiyaku Co., Ltd.), Adekaria soap SE
-1025N or SR-1025 (trade name) (manufactured by Asahi Denka Kogyo Co., Ltd.).

The vinyl monomer having a nonionic group as the reactive emulsifier is not limited to the following, but for example, α- [1-[(allyloxy) methyl] -2- (nonylphenoxy) ethyl]- ω-Hydroxypolyoxyethylene (trade name: Adeka Soap NE
-20, NE-30, NE-40, etc., manufactured by Asahi Denka Kogyo Co., Ltd., polyoxyethylene alkylpropenyl phenyl ether (trade names: Aqualon RN-10, RN-20, RN-3
0, RN-50, etc., manufactured by Daiichi Pharmaceutical Co., Ltd.).

The amount of the emulsifier used in the synthesis of the polymer emulsion particles (B) is preferably within a range of 10 parts by mass or less with respect to 100 parts by mass of the polymer emulsion particles (B) to be obtained. A range of 5 parts by mass is more preferable.

During the synthesis of the polymer emulsion particles (B), the polymerization of the hydrolyzable silicon compound (b1) and the vinyl monomer (b2) having a secondary and / or tertiary amide group is carried out in the presence of a polymerization catalyst. It is preferable.

The polymerization catalyst for the hydrolyzable silicon compound (b1) can be appropriately selected according to the components of the monomer used for the polymerization, and is not limited to the following. For example, halogenation of hydrochloric acid, hydrofluoric acid, etc. Carboxylic acids such as hydrogen, acetic acid, trichloroacetic acid, trifluoroacetic acid and lactic acid; sulfuric acid,
sulfonic acids such as p-toluenesulfonic acid; acidic emulsifiers such as alkylbenzenesulfonic acid, alkylsulfonic acid, alkylsulfosuccinic acid, polyoxyethylene alkylsulfuric acid, polyoxyethylenealkylarylsulfuric acid, polyoxyethylene distyrylphenyl ether sulfonic acid; Acidic or weakly acidic inorganic salts, acidic compounds such as phthalic acid, phosphoric acid, nitric acid; sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, tetramethylammonium chloride, tetramethylammonium hydroxide, tributylamine , Diazabicycloundecene, ethylenediamine, diethylenetriamine, ethanolamines, γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl) -aminopropyltrimethoxysilane Basic compounds such as: tin compounds such as dibutyltin octylate and dibutyltin dilaurate. Among these, acidic emulsifiers are preferable from the viewpoint of not only a polymerization catalyst but also an emulsifier, and alkylbenzenesulfonic acids having 5 to 30 carbon atoms are more preferable.

As the polymerization catalyst for the vinyl monomer (b2) having a secondary and / or tertiary amide group, a radical polymerization catalyst that causes radical polymerization by heat or a reducing substance to cause addition polymerization of the vinyl monomer is preferable. Although not limited to the following, for example, water-soluble or oil-soluble persulfates, peroxides, azobis compounds and the like are used. Specific examples of the polymerization catalyst are not particularly limited. For example, potassium persulfate, sodium persulfate, ammonium persulfate,
Hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, 2,
Examples include 2-azobisisobutyronitrile, 2,2-azobis (2-diaminopropane) hydrochloride, 2,2-azobis (2,4-dimethylvaleronitrile), and the like. The blending amount of the polymerization catalyst is 10% of all vinyl monomers constituting the polymer emulsion particles (B).
0.001-5 mass parts is preferable with respect to 0 mass parts. Incidentally, the acceleration of the polymerization rate, and 70
When you want more low temperature polymerization below ℃, for example, sodium bisulfite, ferrous chloride,
It is preferable to use a reducing agent such as ascorbate or Rongalite in combination with a radical polymerization catalyst.

As described above, the polymer emulsion particles (B) are composed of the hydrolyzable silicon compound (b1) and the vinyl monomer (b2) having a secondary and / or tertiary amide group in the presence of water and an emulsifier.
And, if necessary, other vinyl monomers copolymerizable with the vinyl monomer (b2) (
It can be obtained by polymerization using b3), preferably in the presence of a polymerization catalyst.

Polymerization of the hydrolyzable silicon compound (b1) and the vinyl monomer (b2) having a secondary and / or tertiary amide group can be carried out separately, but by carrying out at the same time,
It is preferable because a micro organic / inorganic composite can be achieved by hydrogen bonding between the two.

The number average particle size of the polymer emulsion particles (B) (primary particle size; the number average particle size of the primary particles of the polymer emulsion particles (B)) is preferably 3 to 100 nm, more preferably from the viewpoint of thixotropic properties. The thickness is 5 to 80 nm, more preferably 10 to 40 nm.
In addition, the number average particle diameter of polymer emulsion particle | grains (B) can be measured by the method described in the below-mentioned Example.
The ratio of the particle diameter (rB) of the polymer emulsion particles (B) to the particle diameter (rA) of the metal oxide (A) is preferably rA <rB and rB <100 nm from the viewpoint of thixotropic properties. More preferably, rA <rB and rB <80 nm, and further rA <rB and rB <40 nm. Although it is not clear about the factors that affect the thixotropy, it is assumed that the number of particles increases as the particle size decreases, and that the interaction in water occurs due to the significant increase in surface area. Furthermore, when the solid content concentration exceeds 6%, it is considered that the collision probability between particles is increased and the thixotropic property becomes remarkable.

The method for obtaining the polymer emulsion particles (B) having such a number average particle diameter is not particularly limited, but the hydrolyzable silicon compound (in the presence of a sufficient amount of water for the emulsifier to form micelles) Examples include a method of synthesizing the polymer emulsion particles (B) by so-called emulsion polymerization in which b1) and / or the vinyl monomer (b2) is polymerized.

The polymer emulsion particles (B) preferably have a core / shell layer structure.
Furthermore, it is preferable that the core layer and the shell layer have different flexibility,
From the viewpoint of void formation, the shell layer is more preferably harder than the core layer. Hardness can be controlled by including a hydrolyzable silicon compound (b1) in the shell layer.
From the viewpoint of coating strength, the weight ratio of the vinyl monomer (b2) contained in the polymer emulsion particles (B) is preferably 20% by mass or more, more preferably 40% by mass or more, and still more preferably. 50 mass% or more is preferable. As long as it is limited to the vinyl monomer (b2) in the core layer, it is preferably 70% or more, more preferably 80% or more, and further preferably 90% or more.
Specifically, in the step of forming the optical coating film of the present embodiment, a coating layer containing the metal oxide (A) and the polymer emulsion particles (B) is applied, and a precursor is formed. Thereafter, sintering is performed. That is, after the precursor is formed in the drying step of removing the solvent from the coating composition, a step of forming the void (X) by sintering is performed. The gap (X
In the step of forming a), all or a part of the polymer emulsion particles (B) are removed.

<Hydrolyzable silicon compound (C)>
The optical coating film of this embodiment includes the above-described metal oxide (A) and polymer emulsion particles (B).
In addition to the above, a hydrolyzable silicon compound (C) may further be contained.
The hydrolyzable silicon compound (C) is preferably one or more hydrolyzable silicon compounds selected from the group consisting of compounds represented by the following formulas (2), (3), and (4). .
The above-mentioned (b1) hydrolyzable silicon compound is a component constituting the polymer emulsion particles (B), and is incorporated integrally in the component (B), and the hydrolyzable silicon compound (C ) Is added separately and independently from the component (A) and the component (B),
It is clearly distinguished from the above-mentioned (b1) hydrolyzable silicon compound.

R1nSiX4-n (2)
(In the formula (2), R1 is a hydrogen atom, a halogen group, a hydroxy group, a mercapto group, an amino group,
A (meth) acryloyl group and an alkyl group having 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, or an aryl group, which may be selected from the group consisting of an epoxy group.
X represents a hydrolyzable group, and n is an integer of 0 to 3. )

X3Si-R2n-SiX3 (3)
(In Formula (3), X3 represents a hydrolyzable group, R2 represents a C1-C6 alkylene group or a phenylene group. N is 0 or 1.)

R3- (O-Si (OR3) 2) n-OR3 (4)
(In Formula (4), R3 represents a C1-C6 alkyl group. N is an integer of 2-8.)

<Content ratio of each component>
The coating composition for forming the optical coating film of this embodiment has a mass ratio ((A) :( B)) of the metal oxide (A) and the polymer emulsion particles (B) of 1: 0.05 to It is preferably 1:10, more preferably 1: 0.1 to 1: 5, and 1: 0.5 to 1: 3.
More preferably.
The mass ratio ((A) :( C)) between the metal oxide (A) and the hydrolyzable silicon compound (C) is:
From the viewpoint of strength, it is preferably 1: 0.05 to 1:10, more preferably 1: 0.1 to 1: 5, and further preferably 1: 0.5 to 1: 2. preferable.
The mass ratio ((A) :( B)) between the metal oxide (A) and the polymer emulsion particles (B) is (A) :( B) = 1: 0.2 to 1 from the viewpoint of thixotropy. : 2 is preferred.

  The mass ratio ((A) :( C)) of the metal oxide (A) and the hydrolyzable silicon compound (C) is 1: 0.05 or more from the viewpoint of mechanical strength and weather resistance. preferable. In addition, the mass ratio ((A) :( C)) of the metal oxide (A) and the hydrolyzable silicon compound (C) increases the porosity and makes the coating film have a low refractive index. 10 or less is preferable. The mass of the hydrolyzable silicon compound (C) is the mass in terms of SiO2 after the hydrolyzable silicon compound (C) is hydrolyzed and condensed.

<Preparation of coating composition>
The coating composition contains a metal oxide (A), preferably a spherical metal oxide (a1), and a non-spherical metal oxide (a2) having an aspect ratio (major axis / minor axis) of 3 to 25 It is preferable to prepare by the 1st process of mix | blending an oxide (A) and polymer emulsion particle | grains (B), and obtaining a mixture, and the 2nd process of adding an acid to the said mixture.
In the case of adding an acid as a hydrolysis catalyst or a condensation catalyst as the “acid”, from the viewpoint of blending stability, the metal oxide (A) and the polymer emulsion particles (B) are blended first, and then the acid. Is preferably added. Or after making it aggregate by adding an acid to the isoelectric point of a metal oxide (A), after neutralizing and stabilizing with a base, you may add a polymer emulsion particle (B).

Examples of the acid include, but are not limited to, hydrogen halides such as hydrochloric acid and hydrofluoric acid; carboxylic acids such as acetic acid, trichloroacetic acid, trifluoroacetic acid, and lactic acid; sulfuric acid, methanesulfonic acid, p- Sulfonic acids such as toluene sulfonic acid; alkylbenzene sulfonic acid,
Acid emulsifiers such as alkylsulfonic acid, alkylsulfosuccinic acid, polyoxyethylene alkylsulfuric acid, polyoxyethylenealkylarylsulfuric acid, polyoxyethylene distyrylphenyl ether sulfonic acid; acidic or weakly acidic inorganic salts, phthalic acid, phosphoric acid, Examples include acidic compounds such as nitric acid.

As solid content of the said coating composition, 1 mass%-10 mass% are preferable, More preferably, 2 mass%-8 mass%, More preferably, 3 mass%-6 mass% are preferable.
If the solid content is 1% by mass or less, the thixotropy becomes insufficient, and if the solid content exceeds 10% by mass, streaks are likely to occur during coating, which is not preferable in appearance.
The viscosity of the coating composition as measured with a B-type viscometer (60 rotations) is preferably 5 to 2000 mPa · s at 25 ° C., preferably 10 to 1000 mPa · s, more preferably 2 to 10 mPa. -S.

The optical coating film of this embodiment is coated with the above coating composition on a substrate and dried,
It is obtained by removing part or all of the polymer emulsion particles (B) to form voids (X). The step of forming this void (X) will be described later.

<The process of apply | coating a coating composition>
The coating composition prepared as described above is applied onto a predetermined material (described as a substrate).
The method for applying the above-described coating composition to the substrate is not particularly limited. For example, spraying, flow coating, roll coating, brush coating, dip coating, spin coating, screen printing, Examples thereof include a casting method, a gravure printing method, a flexographic printing method, and the like. From the viewpoint of productivity, roll coating, screen printing, and gravure printing are preferred. Furthermore, the roll coating method is preferable for the purpose of coating on a large-sized substrate.

As a film thickness which apply | coats the above-mentioned coating composition to a base material, 100 micrometers or less are preferable, More preferably, it is 50 micrometers or less, More preferably, 15 micrometers or less are preferable.
If the thickness exceeds 100 μm, a uniform coating film cannot be obtained, and a partially thick film is formed.

<Step of drying>
After coating the coating composition on the substrate as described above, the coating composition is dried to form a precursor of the optical coating film.
The drying method is not particularly limited, and examples thereof include natural drying, cold air drying, hot air drying, and infrared drying.
The drying temperature is preferably 5 to 700 ° C, more preferably 10 to 300 ° C, and 2
0-200 degreeC is further more preferable, Most preferably, 25 degreeC-150 degreeC is preferable.

<Sintering process>
Furthermore, the precursor of the optical coating film is sintered at a temperature of 500 ° C. or higher as a void forming step.
Preferably, sintering is performed at 500 ° C. to 900 ° C., more preferably 600 ° C. to 800 ° C., and still more preferably 650 ° C. to 750 ° C., and voids can be formed in the coating film. In addition to heat treatment, sintering can also be performed by ultraviolet irradiation such as a high-pressure mercury lamp.
The optical coating film of this embodiment has a thickness of 0.05 to 10 μm in terms of transparency and antireflection properties.
It is preferable that

(Use)
Since the optical coating film of this embodiment is excellent in transparency and antireflection properties, solar cell members (glass, modules, etc.), solar cell condensing lenses, solar power generation mirrors, solar power generation collectors. In an optical glass tube, a photovoltaic cell, a liquid crystal display, glasses, a window glass, a television, and the like, it can be used as an antireflection film for a high-definition member that needs to improve light transmission and / or prevent reflection.

Hereinafter, the present invention will be described with reference to specific examples and comparative examples, but the present invention is not limited thereto.

Various physical properties in Synthesis Examples, Examples, and Comparative Examples described later were measured by the following methods.
((1) Measurement of average particle diameter (nm))
The metal oxide (A) was magnified 50,000 to 100,000 times, and adjusted so that 100 to 200 spherical metal oxide (A) particles appeared, and a transmission micrograph was taken.
Next, the particle diameter (major axis and minor axis) of each photographed metal oxide (A) was measured, and an average value thereof ((major axis + minor axis) / 2) was obtained and used as an average particle diameter.

((2) Measurement of total light transmittance (%))
About the test plate manufactured by the Example and comparative example which are mentioned later, total light transmittance was measured by the method prescribed | regulated to JISK7361-1 using Nippon Denshoku Industries Co., Ltd. turbidimeter NDH2000.

((3) Measurement of pencil hardness)
A test pencil specified by JIS S6006 is manufactured from optical coating films manufactured in Examples and Comparative Examples described later, and 1 kg load is applied according to the pencil hardness evaluation method specified in JIS K5400 using the test pencil. The pencil hardness was evaluated.

((4) Measurement of surface water contact angle (°))
Drops of deionized water (1.0 μL) on the surface of the optical coating film produced in Examples and Comparative Examples described later
And left at 25 ° C. for 10 seconds. Thereafter, the initial contact angle was measured using a CA-X150 contact angle meter manufactured by Kyowa Interface Science, Japan. The smaller the contact angle of water with the optical coating film, the higher the hydrophilicity of the coating surface.

((5) Weather resistance test)
For test plates manufactured in Examples and Comparative Examples described later, an accelerated environment tester (Espec (
EHS-411) was used, and a weather resistance test was performed for 4 hours in an environment of a temperature of 135 ° C. and a humidity of 85%. In addition, the total light transmittance of the test plate after the weather resistance test was measured according to the method described in the above (2).

((6) Measurement of void size of void (X) (Y))
The volume of the void was measured by a nitrogen adsorption method using “Autosorb-1 manufactured by Cantachrome Co., Ltd.”, and the void size was determined. For pores having a pore diameter of 18 nm or less, the void volume was measured by the BJH method to determine the void size.

((7) Number average particle diameter of polymer emulsion particles)
The number average particle diameter of the polymer emulsion particles (B) produced by the synthesis example described later was measured with a dynamic light scattering type particle size distribution analyzer (trade name: Microtrac UPA, manufactured by Nikkiso Co., Ltd.).

((8) AR value, AR change rate)
The total light transmittance before and after the weather resistance test of the test plates manufactured according to Examples and Comparative Examples described later,
Using the total light transmittance of the substrate, the AR value and the AR change rate were calculated by the following formulas (6) and (7).

When the AR is 2% or more, it can be evaluated that the antireflection characteristic is good.
When the absolute value of the AR change rate is 50% or less, it can be evaluated that the weather resistance is good.

((9) Coating uniformity)
Uniformity of the film thickness was measured visually at a magnification of 100 times using a KEYENCE microscope V-1000 and visually evaluated.
○: Uniformity good △: Slightly uniform ×: Defect ((10) thixotropy (TI value)
The viscosity was measured with a B-type viscometer (BRROKFIELD) under the condition of 25 ° C. to determine the TI value.
TI value = 6 rpm viscosity / 60 rpm viscosity × 100

(Synthesis example)
Hereinafter, synthesis examples of the polymer emulsion particles (B) used in Examples and Comparative Examples described later are described.

(Synthesis Example 1)
<Synthesis of Polymer Emulsion Particle (B-1) Water Dispersion>
In a reactor having a reflux condenser, a dropping tank, a thermometer and a stirring device, 1600 g of ion-exchanged water
And 7 g of dodecylbenzenesulfonic acid were added, and the mixture was heated to 80 ° C. with stirring to obtain a mixed solution (1).
To the obtained mixed liquid (1), a mixed liquid (2) of 185 g of dimethyldimethoxysilane and 117 g of phenyltrimethoxysilane (b1-3) was used as a core layer, and the temperature in the reaction vessel was set at 80.
The mixture (3) was obtained by dropwise addition over about 2 hours while maintaining the temperature.
Thereafter, the mixed liquid (3) was stirred for about 1 hour while the temperature in the reaction vessel was 80 ° C.
Next, 150 g of butyl acrylate, 30 g of tetraethoxysilane (b1-3), 145 g of phenyltrimethoxysilane (b1-3) as a shell layer were added to the obtained mixed liquid (3).
And a mixed solution of 1.3 g of 3-methacryloxypropyltrimethoxysilane (b1-3) (4
), 165 g of diethyl acrylamide, 3 g of acrylic acid, 13 g of reactive emulsifier (trade name “Adekaria Soap SR-1025”, manufactured by Asahi Denka Co., Ltd., 25 mass% solid content aqueous solution), 40 g of 2 mass% aqueous solution of ammonium persulfate And a mixture of ion-exchanged water 1900 g (5)
Are simultaneously added dropwise over a period of about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C.
6) was obtained.
Further, as a heat curing, the mixture (6) was stirred for about 2 hours while the temperature in the reaction vessel was 80 ° C.
Thereafter, the mixture (6) was cooled to room temperature, filtered through a 100-mesh wire mesh, the concentration was adjusted with purified water, and an aqueous dispersion (solid content) of polymer emulsion particles (B-1) having a number average particle diameter of 87 nm. 10% by mass, pH 3.2) was obtained.

(Synthesis Example 2)
<Synthesis of Polymer Emulsion Particle (B-2) Water Dispersion>
In a reactor having a reflux condenser, a dropping tank, a thermometer and a stirring device, 1600 g of ion-exchanged water
, And 20 g of dodecylbenzenesulfonic acid were added, followed by heating to 80 ° C. with stirring to obtain a mixed solution (1).
To the obtained mixed liquid (1), a mixed liquid (2) of 185 g of dimethyldimethoxysilane and 151 g of phenyltrimethoxysilane (b1-3) as a core layer was added, and the temperature in the reaction vessel was set to 80.
The mixture (3) was obtained by dropwise addition over about 2 hours while maintaining the temperature.
Thereafter, the mixed liquid (3) was stirred for about 1 hour while the temperature in the reaction vessel was 80 ° C.
Next, 150 g of butyl acrylate, 10 g of tetraethoxysilane (b1-3), 145 g of phenyltrimethoxysilane (b1-3) as a shell layer were added to the obtained mixed liquid (3).
And a mixed solution of 1.3 g of 3-methacryloxypropyltrimethoxysilane (b1-3) (4
), 145 g of diethyl acrylamide, 10 g of acrylic acid, 13 g of reactive emulsifier (trade name “Adekaria Soap SR-1025”, manufactured by Asahi Denka Co., Ltd., solid content 25% by mass aqueous solution), 40 g of 2% by mass aqueous solution of ammonium persulfate , And 1900 g of ion exchange water (5)
Are simultaneously added dropwise over a period of about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C.
6) was obtained.
Further, as a heat curing, the mixture (6) was stirred for about 2 hours while the temperature in the reaction vessel was 80 ° C.
Thereafter, the mixture (6) is cooled to room temperature, filtered through a 100-mesh wire mesh, the concentration is adjusted with water, and an aqueous dispersion (solid content) of polymer emulsion particles (B-2) having a number average particle diameter of 20 nm. 10% by mass, pH 3.2) was obtained.

(Synthesis Example 3)
<Synthesis of Polymer Emulsion Particle (B-3) Water Dispersion>
In a reactor having a reflux condenser, a dropping tank, a thermometer and a stirring device, 1600 g of ion-exchanged water
Then, 5 g of polyvinyl alcohol (PVA217 manufactured by Kuraray Co., Ltd.) and 20 g of dodecylbenzenesulfonic acid were added, followed by heating to 80 ° C. with stirring to obtain a mixed solution (1).
To the obtained mixed liquid (1), a mixed liquid (2) of 185 g of dimethyldimethoxysilane and 151 g of phenyltrimethoxysilane (b1-3) as a core layer was added, and the temperature in the reaction vessel was set to 80.
The mixture (3) was obtained by dropwise addition over about 2 hours while maintaining the temperature.
Thereafter, the mixed liquid (3) was stirred for about 1 hour while the temperature in the reaction vessel was 80 ° C.
Next, 150 g of methyl acrylate, 10 g of tetraethoxysilane (b1-3), 145 g of phenyltrimethoxysilane (b1-3) as a shell layer were added to the obtained mixed liquid (3).
And a mixed solution of 1.3 g of 3-methacryloxypropyltrimethoxysilane (b1-3) (4
), 145 g of diethyl acrylamide, 10 g of acrylic acid, 13 g of reactive emulsifier (trade name “Adekaria Soap SR-1025”, manufactured by Asahi Denka Co., Ltd., solid content 25% by mass aqueous solution), 40 g of 2% by mass aqueous solution of ammonium persulfate And a mixture (5) of 1900 g of ion-exchanged water were simultaneously added dropwise over about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C. to obtain a mixture (6).
Further, as a heat curing, the mixture (6) was stirred for about 2 hours while the temperature in the reaction vessel was 80 ° C.
Thereafter, the mixture (6) is cooled to room temperature, filtered through a 100-mesh wire mesh, the concentration is adjusted with water, and an aqueous dispersion (solid content) of polymer emulsion particles (B-3) having a number average particle diameter of 25 nm. 10 mass%, pH 3.3) was obtained.

(Synthesis Example 4)
<Synthesis of Polymer Emulsion Particle (B-4) Water Dispersion>
In a reactor having a reflux condenser, a dropping tank, a thermometer and a stirring device, 2600 g of ion-exchanged water
, And 12 g of dodecylbenzenesulfonic acid and 20 parts of 25% aqueous solution of polyoxyethylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation) were added, and the mixture was heated to 80 ° C. with stirring and mixed (1) Got.
In the obtained mixed liquid (1), 18 g of methacrylic acid and 21 methyl methacrylate were used as the core layer.
A mixture (2) of 6 g, 216 g of butyl acrylate, 6.9 g of 3-methacryloxypropyltrimethoxysilane (b1-3), 101 g of methyltrimethoxysilane, and 40 g of a 2% by weight aqueous solution of ammonium persulfate in a reaction vessel Was added dropwise over about 2 hours while maintaining the temperature at 80 ° C. to obtain a mixed liquid (3).
Thereafter, the mixed liquid (3) was stirred for about 1 hour while the temperature in the reaction vessel was 80 ° C.
Next, 245 g of butyl acrylate, 245 g of methyl methacrylate, 10 g of acrylic acid, a reactive emulsifier (trade name “Adekari Soap SR” was added to the obtained mixed liquid (3) as a shell layer.
-1025 ", manufactured by Asahi Denka Co., Ltd., 25 g solid content aqueous solution (13 g), ammonium persulfate 2 mass% aqueous solution 40 g, and ion-exchanged water 1900 g mixed solution (4), the temperature in the reaction vessel was 80 The mixture (5) was obtained by simultaneously dropping over about 2 hours while maintaining the temperature at ° C.
Further, as a heat curing, the mixture (5) was stirred for about 2 hours while the temperature in the reaction vessel was 80 ° C.
Thereafter, the mixture (5) was cooled to room temperature, filtered through a 100-mesh wire mesh, the concentration was adjusted with purified water, and an aqueous dispersion of polymer emulsion particles (B-5) having a number average particle size of 120 nm (
A solid content of 10% by mass, pH 3.2) was obtained.

[Example 1]
Polymer emulsion particles (B) synthesized in Synthesis Example 2 as polymer emulsion particles (B)
-2) was used. Water-dispersed colloidal silica having an average particle size of 5 nm (trade name “Snowtex OXS (described as“ ST-OXS ”in Table 1)”) as a raw material for the spherical metal oxide (A), manufactured by Nissan Chemical Industries, Ltd. , Solid content of 10% by mass).
Tetraethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the hydrolyzable silicon compound (C).
These were mixed at a solid content mass ratio shown in Table 1, adjusted with purified water to a solid content of 6%, and then stirred to obtain a coating composition.

The top coating composition was applied to a substrate (5 cm × 5 cm concavo-convex template glass) using a spin coater so as to have a film thickness of 100 nm, then dried at 25 ° C. for 10 minutes, and further 600 in an electric furnace. A test plate having a coating film was obtained after quenching after sintering at 3 ° C. for 3 minutes.
At this time, the composition ratio in the coating film (similar to the mass ratio of each component calculated in terms of solid content of the coating composition) is (A) / (B ′) / (C ′) = 100/100/45. It was.
In addition, (B ′) is a polymer particle derived from the polymer emulsion particles (B) obtained after the sintering, and (C ′) is a hydrolyzable silicon compound (C) obtained after the sintering. The hydrolysis condensate of

[Example 2]
Polymer emulsion particles (B) synthesized in Synthesis Example 3 as polymer emulsion particles (B)
The aqueous dispersion of -3) was used. Water-dispersed colloidal silica having an average particle size of 5 nm (trade name “Snowtex OXS (described as“ ST-OXS ”in Table 1)”) as a raw material for the spherical metal oxide (A), manufactured by Nissan Chemical Industries, Ltd. , Solid content of 10% by mass).
As the hydrolyzable silicon compound (C), tetramethoxysilane oligomer MS56 (manufactured by Mitsubishi Chemical Corporation) was used as the hydrolyzable silicon compound (C).
These were mixed at a solid content mass ratio shown in Table 1, adjusted with purified water to a solid content of 6%, and then stirred to obtain a coating composition.

The above-mentioned coating composition was applied to a base material (5 cm × 5 cm concavo-convex template glass) using a spin coater so as to have a film thickness of 100 nm, then dried at 25 ° C. for 10 minutes, and further 600 in an electric furnace. A test plate having a coating film was obtained after quenching after sintering at 3 ° C. for 3 minutes.
At this time, the composition ratio in the coating film (similar to the mass ratio of each component calculated in terms of solid content of the coating composition) is (A) / (B ′) / (C ′) = 100/100/45. It was.
In addition, (B ′) is a polymer particle derived from the polymer emulsion particles (B) obtained after the sintering, and (C ′) is a hydrolyzable silicon compound (C) obtained after the sintering. The hydrolysis condensate of

[Comparative Example 1]
Polymer emulsion particles (B) synthesized in Synthesis Example 1 as polymer emulsion particles (B)
An optical coating film was obtained in the same manner as in Example 1 except that the aqueous dispersion of -1) was used. The evaluation results are shown in Table 1.

[Comparative Example 2]
Polymer emulsion particles (B) synthesized in Synthesis Example 4 as polymer emulsion particles (B)
An optical coating film was obtained in the same manner as in Example 1 except that the aqueous dispersion of -4) was used.

  The evaluation results of Examples 1-2 and Comparative Examples 1-2 described above are shown in Table 1 below.

As shown in Table 1, in Examples 1 and 2, it has an excellent antireflection effect with the possibility of forming a uniform film thickness on uneven substrates, and is also totally reflective after the weather resistance test It turned out that the fall of the transmittance | permeability is suppressed.
On the other hand, in Comparative Examples 1 and 2, it was confirmed that the antireflection characteristics were inferior due to insufficient uniformity with respect to the uneven substrate, and the total reflection transmittance was lowered after the weather resistance test. .

The optical coating film of the present invention is an antireflection film for a high-definition member that needs to improve light transmission and / or prevent reflection, such as solar cells, photovoltaic cells, liquid crystal displays, glasses, window glass, and televisions. The present invention has industrial applicability as an antifouling coating for these members.

Claims (13)

A coating composition comprising a metal oxide (A) and polymer emulsion particles (B), wherein the coating composition has a TI value of 2 to 10, wherein the coating composition is for an optical coating film. The coating composition for an optical coating film according to claim 1, wherein the coating composition has a solid content concentration of 6% and a TI value of 2 to 10. The ratio between the particle size (rA) of the metal oxide (A) and the particle size (rB) of the polymer emulsion particles (B) is rA <rB and rB <100 nm. The coating composition for optical coating films described in 1. By applying the coating composition for an optical coating film according to any one of claims 1 to 3 and drying the precursor of the optical coating film formed at a temperature of 500 ° C or higher. An optical coating film that is formed. The process of apply | coating the coating composition for optical coating films as described in any one of Claims 1 thru | or 3, and drying, and forming the precursor of an optical coating film, and the said temperature is 500 degreeC or more And a step of forming an optical coating film by sintering the optical coating film. At least the average value of the major axis (L) and the maximum value (D) of the minor axis perpendicular to the major axis (L): (void size = (L + D) / 2) has a void (X) of 20 nm or more, and the void (X) 5. The optical axis according to claim 4, wherein the major axis (L) and the minor axis (D) are 1 <L / D, and the gap (X) is not in contact with the base material at the interface with the base material. Paint film.   The optical coating film according to claim 6, further comprising a void (Y) having a void size of less than 20 nm around the void (X).   The antireflection film comprised from the optical coating film as described in any one of Claim 4, 6 or 7. Glass for solar cells containing the antireflection film according to claim 8. A solar cell module comprising the antireflection film according to claim 8. The condensing lens for solar cells containing the antireflection film of Claim 8. A solar power generation mirror comprising the antireflection film according to claim 8. The condensing glass tube for solar power generation containing the antireflection film of Claim 8.