JP2015075707A - Article having transparent base material and stain-resistant anti-reflection film, and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an article having a transparent base material and a stain resistant anti-reflection film, which offers better stain resistance while maintaining anti-reflection performance of a silica-based porous layer.SOLUTION: An article of the present invention includes a transparent base material and a stain resistant anti-reflection film formed on the transparent base material, where the stain resistant anti-reflection film includes a silica-based porous layer and a nanosheet layer in order from the transparent base material side, the silica-based porous layer having a refractive index in a range of 1.10-1.38, the nanosheet layer comprising a plurality of nanosheets having refractive indexes in a range of 1.30-1.80. A surface of the stain resistant anti-reflection film has a water contact angle of less than 60°, and the number of pores having openings thereon with opening diameters of 20 nm or greater is no more than 8 per 10nm.

Description

  The present invention relates to an article comprising a transparent substrate and an antifouling antireflection film and a method for producing the same.

Articles having an antireflection film on the surface of a transparent substrate such as a glass plate are used as cover members for solar cells, various displays and their front plates, various window glasses, touch panel cover members, and the like.
The antireflection film is disposed on the outermost layer of the article because of its function. For this reason, the antireflection film is required to have antifouling properties (that dirt is difficult to adhere and can be easily removed even if it adheres).

One example of an antireflection film used for a transparent substrate such as a glass plate is a silica-based porous film (also referred to as “silica-based porous layer” in this specification) (for example, Patent Document 1). Since the silica-based porous film has pores in a matrix containing silica as a main component, the refractive index is lower than that in the case where there are no pores.
However, since the silica-based porous film has a large number of fine open holes and irregularities on the surface, dirt such as oil dirt and resin is likely to adhere, and the attached dirt is difficult to remove.
For example, in the manufacturing process of the solar battery module, a process of bonding the cover member and the solar battery cell with a sealing material is performed. When a silica-based porous film is used as the antireflection film, there is a problem that EVA, which is a sealing material, penetrates into the silica-based porous film in the manufacturing process and the antireflection performance is lowered. Moreover, the soaked EVA is difficult to remove from the silica-based porous membrane, and even after the removal, the portion of the silica-based porous membrane soaked with EVA has a different color from the other portions and looks good. There are also problems such as bad.

As a countermeasure against the problems in the above manufacturing process and the like, a method of applying a fluorine-based coating agent to the surface of a silica-based porous film has been proposed (for example, Patent Document 2). That is, in this method, the antifouling property against oil stains and EVA can be improved by applying a fluorine-based coating agent.
However, depending on the coating agent, there is a concern that the antireflection performance may be deteriorated by immersing in the silica-based porous film during coating.
Further, there are measures such as covering the surface of the silica-based porous membrane with a resin antifouling sheet and peeling off the antifouling sheet after the production process, but there are significant cost issues.

Special table 2010-509175 JP-A-5-330856

  The present invention has been made in view of the above circumstances, and an article provided with a transparent base material and an antifouling antireflection film, which has improved antifouling properties while maintaining the antireflection performance of the silica-based porous layer, and its An object is to provide a manufacturing method.

The present invention has the following aspects.
[1] A transparent substrate and an antifouling antireflection film provided on the transparent substrate,
The antifouling antireflection film has a silica-based porous layer and a nanosheet layer in order from the transparent substrate side,
The silica-based porous layer has a refractive index in the range of 1.10 to 1.38,
The nanosheet layer has a plurality of nanosheets having a refractive index of 1.30 to 1.80,
The water contact angle on the surface of the antifouling antireflection film is less than 60 °,
The number of holes having an opening diameter of 20 nm or more opened on the surface of the antifouling antireflection film is 8/10 ⁶ nm ² or less.
[2] The article according to [1], wherein the silica-based porous layer includes a dense layer on the nanosheet layer side, and an average layer thickness d1 of the dense layer and the nanosheet layer is 1 to 10 nm.
[3] The article according to [2], wherein the silica-based porous layer includes a porous layer on the transparent substrate side, and the average layer thickness d2 of the porous layer is 60 to 200 nm.
[4] The article according to [2] or [3], wherein a ratio (d1 / d2) of the average layer thickness d1 to the average layer thickness d2 of the porous layer is 0.005 to 0.17.
[5] The article according to any one of [1] to [4], wherein the nanosheet is derived from an inorganic layered compound selected from layered polysilicates and clay minerals.
[6] The article according to any one of [1] to [5], comprising an undercoat layer between the transparent substrate and the antifouling antireflection film.
[7] The article according to any one of [1] to [6], wherein an average opening diameter of pores in a longitudinal section of the silica-based porous layer is 15 to 100 nm.
[8] A method for producing an article, comprising a transparent substrate and an antifouling antireflection film provided on the transparent substrate,
A step of applying a coating liquid for forming a silica-based porous layer containing a matrix precursor (A), particles (B), and a liquid medium (C) onto a transparent substrate, and a matrix precursor ( Forming a silica-based porous layer, comprising: forming a matrix from A); and removing the particles (B) before or after or during the heat treatment after the coating;
Applying a nanosheet layer forming coating solution on the surface of the silica-based porous layer and drying to form a nanosheet layer;
The matrix precursor (A) comprises at least one compound (A1) selected from a compound (a1) represented by the following general formula (a1), a hydrolyzate and a partial condensate thereof, and the following general formula (a2) And at least one compound (A2) selected from the hydrolyzate and partial condensate thereof, and the compound (A1) in the matrix precursor (A) And the ratio of the content of the compound (A2) is in the range of 5 to 60 in terms of the molar ratio ((a1) / (a2)) between the compound (a1) and the compound (a2). The average primary particle diameter of the particles (B) is 20 to 130 nm,
The nanosheet layer forming coating solution contains a plurality of nanosheets and a dispersion medium of the nanosheet, and the nanosheet has a refractive index of 1.30 to 1.80.
SiX ₄ (a1)
Y _n SiX _4-n (a2)
[Wherein, X represents a hydrolyzable group, Y represents a non-hydrolyzable group having a dielectric constant of Y-OH of 35 F / m or less, and n represents an integer of 1 to 3. ]
[9] For forming a silica-based porous layer, the step of forming the silica-based porous layer comprises a matrix precursor (A), particles (B1) that can be removed by heat treatment, and a liquid medium (C). The production of an article according to [8], comprising: applying a coating liquid on a transparent substrate; and forming a matrix from the matrix precursor (A) by heat treatment and removing the particles (B1). Method.
[10] The method for producing an article according to [8] or [9], wherein the drying temperature in the step of forming the nanosheet layer is 300 ° C. or lower.

  ADVANTAGE OF THE INVENTION According to this invention, the article | item provided with the transparent base material and antifouling antireflection film which improved antifouling property, maintaining the antireflection performance of a silica type porous layer, and its manufacturing method can be provided.

It is a schematic sectional drawing which shows the article | item of 1st embodiment of this invention. It is a schematic sectional drawing which shows the article | item of 2nd embodiment of this invention.

<First embodiment of the present invention>
In FIG. 1, the schematic sectional drawing of the articles | goods of 1st embodiment of this invention is shown.
The article 1 of the present embodiment includes a transparent substrate 10 and an antifouling antireflection film 20 formed on the surface of the transparent substrate 10.

(Transparent substrate 10)
Examples of the shape of the transparent substrate 10 include a plate and a film.
Examples of the material of the transparent substrate 10 include glass and resin.
Examples of the glass include soda lime glass, borosilicate glass, aluminosilicate glass, and alkali-free glass.
Examples of the resin include polyethylene terephthalate, polycarbonate, triacetyl cellulose, polymethyl methacrylate, and the like.

As the transparent substrate 10, a glass plate is preferable.
The glass plate may be a smooth glass plate formed by a float method or the like, or may be a template glass having irregularities on the surface. Further, not only flat glass but also glass having a curved surface shape may be used.
The thickness of the glass plate is not particularly limited, and glass having a thickness of 10 mm or less can be used. The thinner the thickness, the lower the light absorption, which is preferable for the purpose of improving the transmittance.

When a glass plate is soda lime glass, what has the following composition is preferable.
In mass percentage display based on oxide,
SiO _2: 65~75%,
Al ₂ O _3: 0~10%,
CaO: 5 to 15%,
MgO: 0 to 15%,
Na ₂ O: 10~20%,
K ₂ O: 0 to 3%,
Li ₂ O: 0 to 5%,
Fe ₂ O ₃ : 0 to 3%,
TiO _2: 0~5%,
CeO ₂ : 0 to 3%,
BaO: 0 to 5%,
SrO: 0 to 5%,
B ₂ O _3: 0~15%,
ZnO: 0 to 5%,
ZrO ₂ : 0 to 5%,
SnO ₂ : 0 to 3%,
SO ₃ : 0 to 0.5%.

When a glass plate is an alkali free glass, what has the following composition is preferable.
In mass percentage display based on oxide,
SiO _2: 39~70%,
Al ₂ O ₃ : 3 to 25%,
B ₂ O _3: 1~30%,
MgO: 0 to 10%,
CaO: 0 to 17%,
SrO: 0 to 20%,
BaO: 0 to 30%.

When the glass plate is a mixed alkali glass, those having the following composition are preferred.
In mass percentage display based on oxide,
SiO _2: 50~75%,
Al ₂ O _3: 0~15%,
MgO + CaO + SrO + BaO + ZnO: 6 to 24%,
_{Na 2 O + K 2 O:} 6~24%, including.

  When used as a cover glass for a solar cell, the glass plate is preferably a satin-patterned template glass with an uneven surface. As the template glass, soda lime glass (white plate glass) having a lower iron component ratio (high transparency) than soda lime glass (blue plate glass) used for ordinary window glass or the like is preferable.

  The glass plate may be pre-strengthened. The strengthening treatment includes physical strengthening in which the glass plate is air-cooled after being exposed to a high temperature, or an alkali with a small atomic diameter present on the outermost surface of the glass substrate by immersing the glass plate in a molten salt containing an alkali metal. Examples include chemical strengthening that replaces a metal (ion) with an alkali metal (ion) having a large atomic diameter present in a molten salt. By the strengthening treatment, the strength of the glass is improved, and for example, it is possible to reduce the plate thickness while maintaining the strength. From the viewpoint of reducing the weight of the cover glass, when a glass plate having a thickness of 2 mm or less is required, the glass plate is an aluminosilicate glass having a large component of aluminum oxide and is tempered by chemical strengthening treatment. It is preferable.

(Anti-fouling antireflection film 20)
The antifouling antireflection film 20 includes a silica-based porous layer 21 and a nanosheet layer 26 in order from the transparent substrate 10 side.

{Silica-based porous layer 21}
The silica-based porous layer 21 has a plurality of pores in a matrix 23 mainly composed of silica, and includes pores 24 having a diameter of 20 nm or more as the pores. Moreover, the refractive index of the silica type porous layer 21 exists in the range of 1.10-1.38.
The silica-based porous layer 21 includes a porous layer 22 on the transparent substrate side and a dense layer 25 on the nanosheet layer side.

The silica-based porous layer 21 has a low refractive index (reflectance) because the matrix 23 is mainly composed of silica. Moreover, it is excellent in chemical stability, adhesiveness with the transparent base material 10, abrasion resistance, and the like. In addition, since the matrix 23 has the holes 24 having a diameter of 20 nm or more, the refractive index is lower than that in the case where the holes 24 are not provided.
The silica-based porous layer 21 may have pores with an opening diameter of less than 20 nm in the matrix 23.

Porous layer 22:
The silica-based porous layer 21 includes a porous layer 22 on the transparent substrate side. The porous layer 22 includes more pores 24 and less matrix portions than the dense layer 25.
In this specification, the porous layer 22 has a 900 nm parallel to the outermost surface in an image of a longitudinal section of the antifouling antireflection film 20 obtained using a scanning electron microscope (hereinafter also referred to as “SEM”). On the line, it is defined as a layer in which the ratio of the later-described matrix 23 portion is 50% or less.

Average layer thickness d2 of the porous layer 22:
The average layer thickness d2 of the porous layer 22 is preferably 60 to 200 nm, and more preferably 80 to 150 nm. When the average layer thickness of the silica-based porous layer 21 is equal to or greater than the lower limit, light interference occurs in the visible light region, and antireflection performance is exhibited. When the average layer thickness of the silica-based porous layer 21 is not more than the above upper limit value, the film can be formed without generating cracks.
The method for measuring the average layer thickness is as shown in the examples described later.

Matrix 23:
That the matrix 23 has silica as a main component means that the ratio of silica is 90% by mass or more in the matrix (100% by mass).
The matrix 23 is preferably substantially made of silica. The phrase “substantially composed of silica” means that it is composed only of silica excluding inevitable impurities (for example, a structure derived from the compound (a2) described later).
The matrix 23 may contain a small amount of components other than silica. The components include Li, B, C, N, F, Na, Mg, Al, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, and Sr. , Y, Zr, Nb, Ru, Pd, Ag, In, Sn, Hf, Ta, W, Pt, Au, Bi, and compounds such as one or more ions and oxides selected from lanthanoid elements .
The matrix 23 may include not only two-dimensionally polymerized matrix components but also three-dimensionally polymerized nanoparticles. Examples of the composition of the nanoparticles include Al ₂ O ₃ , SiO ₂ , SnO ₂ , TiO ₂ , ZnO, and ZrO ₂ . The size of the nanoparticles is preferably 1 to 100 nm. The shape of the nanoparticles is not particularly limited, and examples thereof include a spherical shape, a needle shape, a hollow shape, a sheet shape, and a square shape.

Hole 24:
The silica-based porous layer 21 has pores 24 having a diameter of 20 nm or more. Thereby, the excellent antireflection performance is obtained.
When the conventional silica-based porous layer includes pores having a diameter of 20 nm or more, the pores are connected to form continuous pores, and many open pores are also formed on the membrane surface. Therefore, the durability is poor, and when the moisture resistance test and the wear test are performed, the porous structure is broken and the antireflection performance tends to be lowered. However, in the present invention, since the number of open holes is small, the matrix 23 has excellent durability even though the matrix 23 includes holes 24 having a diameter of 20 nm or more.
Whether or not the pores 24 having a diameter of 20 nm or more exist in the matrix 23 is determined based on whether the pores having an opening diameter of 20 nm or more are present in the longitudinal cross-sectional 900 nm × 900 nm image of the antifouling antireflection film 20 obtained using SEM. Judgment is made by whether or not it is observed. When the shape of the opening observed in the image is not a perfect circle, the average value of the short diameter and the long diameter is set as the opening diameter of the hole.

The average opening diameter of pores in the longitudinal section of the silica-based porous layer 21 (hereinafter also referred to as “average opening diameter”) is preferably 15 to 100 nm, and more preferably 20 to 80 nm. If the average opening diameter is not less than the above lower limit value, sufficient antireflection performance as an antireflection film can be obtained, and if it is not more than the above upper limit value, the durability and light transmittance of the silica-based porous layer 21 are good. is there.
The average opening diameter is obtained by averaging the opening diameters of 100 holes selected at random in the longitudinal section of the antifouling antireflection film 20 obtained using SEM. In calculating the average opening diameter, holes having an opening diameter of 3 nm or less were excluded from the target.

The pores 24 having a diameter of 20 nm or more present in the silica-based porous layer 21 are preferably not independent holes but independent holes.
Independent pores indicate granular pores that exist independently in the matrix. It is preferable that the pores 24 existing inside the silica-based porous layer 21 are independent pores, so that water vapor or the like hardly penetrates the interface between the glass and the film and is excellent in heat and moisture resistance. Further, if the holes 24 are independent holes, the antifouling property can be improved.
For example, in the production method described later, organic polymer nanoparticles are used as particles (B), and the pores 24 existing inside the silica-based porous layer obtained by pyrolyzing the particles are independent pores, There are one hole 24 separately.
On the other hand, conventionally, a silica-based porous layer obtained by a method of dispersing inorganic nanoparticles in a matrix, which is a common method for producing a silica-based porous layer, has voids between the particles forming continuous pores. Cheap. When the inside of the film is composed of continuous holes, even if a dense layer is formed on the outermost surface, water vapor and the like easily penetrate into the interface between the glass and the film, so that the heat and moisture resistance tends to be insufficient.

Dense layer 25:
The silica-based porous layer 21 includes a dense layer 25 on the nanosheet layer side. The dense layer 25 has fewer pores 24 and more matrix portions than the porous layer 22.
In the present specification, in the dense layer 25, in the longitudinal cross-sectional image of the antifouling antireflection film 20 obtained using SEM, the ratio of the matrix 23 portion exceeds 900% on the 900 nm line parallel to the outermost surface. Is defined as a layer.

The silica-based porous layer 21 is applied with a silica-based porous layer forming coating liquid (a coating liquid containing the compound (A1), the compound (A2), the particles (B), and the liquid medium (C)), which will be described later. In the case of forming through a heat treatment step, the composition of the matrix 23 of the dense layer 25 is different from that of the porous layer 22.
Although described in detail in “Production Method for Article 1” later, when a silica-based porous layer forming coating solution is applied to the surface of an article such as a glass plate, the compound (A2) is coated by phase separation of the coating solution. Move to the upper layer. Thereby, the compound (A2) phase formed on the nanosheet layer side of the coating film becomes the dense layer 25 by heat treatment.
Therefore, the matrix 23 constituting the dense layer 25 is substantially made of a heat-treated product of the compound (A2) and includes a structure derived from the compound (a2) (for example, a non-hydrolyzable group Y).
In addition, the matrix 23 which comprises the porous layer 22 is substantially comprised from the heat processing thing of the compound (A1), and the structure derived from the compound (a2) is not included or is very little.

Refractive index:
The refractive index of the silica-based porous layer 21 is in the range of 1.10 to 1.38. Preferably, it exists in the range of 1.10-1.30, More preferably, it exists in the range of 1.15-1.25. If the refractive index of the silica-based porous layer 21 is not more than the above upper limit value, there are sufficient pores 24 in the silica-based porous layer 21, and the reflectance of the silica-based porous layer 21 becomes sufficiently low, Excellent anti-reflection performance. If the refractive index of the silica type porous layer 21 is more than the said lower limit, the porosity of the silica type porous layer 21 will not become high too much, but durability will improve.
The method for measuring the refractive index of the silica-based porous layer 21 is the same as the “refractive index” measuring method shown in the examples described later.

{Nanosheet layer 26}
The nanosheet layer 26 contains a plurality of nanosheets. The nanosheet layer 26 does not necessarily have to cover the entire surface of the silica-based porous layer 21, but it is preferable from the viewpoint of antifouling properties to cover the entire surface of the silica-based porous layer 21. .
The refractive index of the nanosheet is 1.30 to 1.80, preferably 1.35 to 1.5.
The refractive index of the nanosheet is a value obtained by calculating from the reflectance obtained by spectral reflectance measurement.

Nanosheet:
The nanosheet is a planar substance obtained by peeling off the inorganic layered compound. In the present invention, the refractive index may be 1.30 to 1.80, and can be appropriately selected from known nanosheets.
The nanosheet having a refractive index of 1.30 to 1.80 is derived from an inorganic layered compound selected from layered polysilicate (refractive index 1.45) and clay mineral (refractive index 1.56 to 1.58). preferable. The nanosheet derived from the inorganic layered compound has a lower hydrophobicity than the fluorine-based coating agent, and has a relatively low water repellency on the surface of the antifouling layer formed. Therefore, if the article 1 includes the nanosheet layer 26 including the nanosheet derived from the inorganic stratiform compound, it is likely to be generated by a fluorine-based coating agent when installed outdoors, and dirt is scattered evenly by rainwater and the like. Therefore, the problem that water marks are left due to rainwater or the like is less likely to occur. Moreover, it becomes easy to maintain a favorable external appearance over a long period of time.
The inorganic layered compound has a structure in which a plurality of nanosheets are laminated, and natural products and synthetic products are commercially available. A nanosheet can be obtained by peeling off the layer constituting the inorganic layered compound.
In the present invention, the clay mineral means one having an octahedral structure such as AlO _{6 in the} crystal structure, and the layered polysilicate is different from the clay mineral in that it does not have the octahedral structure.

Examples of the layered polysilicate include kanemite, macatite, magadiite, kenyanite, octosilicate and the like.
The composition of the layered polysilicate can be represented by the following composition formula (1). Examples of the alkali metal atom in M include Na, K, and Li.
M ₂ O · xSiO ₂ · yH ₂ O (1) [wherein, M is an alkali metal atom, x is an integer of 2 to 40, and y is an integer of 1 to 20. ]

  Examples of the clay mineral include smectite, vermiculite, layered double hydroxide (LDH) and the like. Examples of the smectite include 2-octahedron type (saponite, hectorite, etc.) and 3-octahedron type (montmorillonite, beidellite, etc.).

The composition of 2-octahedral smectite can be expressed by the following composition formula (2) (including interlayer cations). The composition of 3-octahedron smectite can be expressed by the following composition formula (3) (including interlayer cations).
(M ¹ , M ² ) _0.3 (M ³ , M ⁴ ) ₃ (Si, Al) ₄ O ₁₀ (F, OH) ₂ .4H ₂ O (2)
(M ¹ , M ² ) _0.3 (M ³ , M ⁴ ) ₂ (Si, Al) ₄ O ₁₀ (F, OH) ₂ .4H ₂ O (3)
In the formula, M ^{1 to} M ⁴ are each independently an alkali metal atom, an alkaline earth metal atom, or a transition metal atom. Examples of the alkali metal atom are the same as described above. Examples of the alkaline earth metal include Mg and Ca. Examples of transition metal atoms include Fe and Al.

The composition of vermiculite can be expressed by the following composition formula (4).
(Mg, Fe, Al) ₃ (Al, Si) ₄ O ₁₀ (OH) ₂ .4H ₂ O (4)

The composition of LDH can be expressed by the following composition formula (5) (including interlayer anions).
[M ⁵ _1-p M ⁶ _p (OH) ₂ ] · [A _{p / n} · qH ₂ O] (5)
In the formula, M ⁵ is a divalent metal ion (Mg ²⁺ , Ca ²⁺ , Zn ²⁺ , Ni ²⁺ etc.), M ⁶ is a trivalent metal ion (Al ³⁺ , Fe ³⁺ , Cr ³⁺ etc.), A is an n-valent anion, and n is an integer of 1 to 3. Examples of A include Cl ⁻ , NO ³⁻ , CO ₃ ^{2− and the} like.

  Of the above, the inorganic layered compound is preferably a clay mineral, and particularly preferably smectite. In the layered polysilicate, hydroxyl groups are exposed on the layer surface, whereas in the clay mineral, the hydroxyl groups are not exposed on the layer surface. For this reason, compared with the nanosheet obtained from the layered polysilicate, the nanosheet obtained from the clay mineral has weak adhesion to the silica-based porous layer 21, and the nanosheet layer 26 is easily washed away by exposure outdoors. When the nanosheet layer 26 disappears with time, the low-reflective property of the silica-based porous layer 21 is sufficiently developed.

As the nanosheet material, titanium oxides such as Ti _0.91 O ₂ and Ti _1.73 Li _0.27 O ₂ , manganese oxides such as MnO ₂ , oxidations such as Nb ₆ O ₁₇ and Nb ₃ O _8, etc. Transition metal oxides such as niobium and tungsten oxides such as WO ₃ ; Transition metal chalcogenides such as MoS ₂ ; Layered perovskite such as Ca ₂ Nb ₃ O ₁₀ and La ₂ Nb ₂ O ₇ However, these materials have low transparency or are transparent but have a high refractive index. Therefore, when a nanosheet derived from these materials is used for the antifouling layer, the antireflection performance is lowered, which is not preferable.

  The average thickness of the nanosheet is preferably 0.5 to 5 nm, more preferably 0.7 to 3 nm. If the average thickness of the nanosheet is equal to or more than the lower limit value, the structure of each nanosheet is difficult to be destroyed, and the durability of the nanosheet layer 26 is increased. If the average thickness of the nanosheet is not more than the above upper limit value, an antifouling layer described later can be easily formed into a thin film (for example, the average layer thickness d1 is 10 nm or less). The average thickness of the nanosheet can be calculated from an SEM image, for example.

Area of the nanosheet is preferably 100 nm ² or more, more preferably 200 nm ² or more, more preferably 400 nm ² or more. If the nanosheet area is 100 nm ² or more, when the nanosheet layer forming coating liquid to be described later is applied to form the nanosheet layer 26, the nanosheet is less likely to enter the silica-based porous layer 21, and the silica-based porous layer The surface is well coated with nanosheets. Although not limit the area of the nanosheet particularly limited, dispersibility in nanosheets layer forming coating composition, in view of easy availability and the like, preferably 1000000Nm ² or less, 250000Nm ² or less being more preferred. The area of the nanosheet can be calculated from an SEM image, for example.

In view of these, examples of the nanosheet, preferably has an average mean area of thickness and 100～1000000Nm ² of 0.5 to 5 nm, the average mean thickness and 200～1000000Nm ² of 0.7~3nm Those having an area are more preferable, and those having an average thickness of 0.7 to 3 nm and an average area of 200 to 250,000 nm ² are more preferable.

As a nanosheet, you may contain the nanosheet surface-modified with processing agents, such as surfactant. By containing the surface-modified nanosheet, the attached dirt can be easily peeled off, and sufficient antifouling property can be obtained with a small amount.
Surfactants include alkyl carboxylic acid salts such as sodium octoate, potassium octoate, sodium decanoate, potassium decanoate, sodium laurate, potassium laurate, sodium stearate, potassium stearate, sodium hexanesulfonate, hexane Alkyl sulfonates such as potassium sulfonate, sodium octane sulfonate, potassium octane sulfonate, sodium decane sulfonate, potassium decane sulfonate, sodium dodecane sulfonate, potassium dodecane sulfonate, sodium lauryl sulfate, potassium lauryl sulfate, myristyl sulfate Sulfate esters such as sodium and potassium myristyl sulfate, phosphate esters such as sodium lauryl phosphate and sodium tripolyphosphate, tetramethylammonium Mubromide, tetramethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, octyltrimethylammonium chloride, octyltrimethylammonium bromide, decyltrimethylammonium chloride, decyltrimethylammonium bromide, triethanolamine chloride, triethanolamine bromide, tripropanolamine Non-ionic such as quaternary alkyl ammonium such as chloride, tripropanolamine bromide, polyoxyethylene alkyl ammonium chloride, polyoxyethylene alkyl ammonium bromide, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, cetanol, oleyl alcohol, etc. Surface activity Agent, and the like.
Treatment agents other than surfactants include trimethylsilyl chloride, triethylsilyl chloride, t-butyldimethylsilane, tri-i-propylsilyl chloride, chloromethyltrimethylsilane, triethylsilane, butyldimethylsilane, trimethylvinylsilane, allyltrimethylsilane, Examples of the silylating agent include hexamethyldisilazane.
In addition, when peeling a nanosheet from an inorganic layered compound, this peeling may be performed in water containing a surfactant. The nanosheet dispersion liquid thus obtained contains nanosheets surface-modified with a surfactant.
The nanosheet contained in the nanosheet layer 26 may be one type or two or more types.

binder:
The nanosheet layer 26 may contain a binder in addition to the nanosheet. By including a binder, the adhesion between a plurality of nanosheets, the denseness of the nanosheet layer 26, the removability of the nanosheet layer 26 when exposed outdoors, and the like can be improved.
Although it does not specifically limit as a binder, The thing melt | dissolved in the dispersion medium used for the coating liquid for nanosheet layer formation mentioned later is preferable. Since the dispersion medium of the coating composition for forming a nanosheet layer often contains water, the binder itself or its precursor is preferably water-soluble. For example, a hydrolyzate of a hydrolyzable silane compound ( Silane hydrolysis sol), condensates thereof, and water-soluble polymers. A water-soluble polymer is more preferable as the binder. The water-soluble polymer is easily deteriorated by ultraviolet rays, wind and rain, etc. when exposed outdoors, and therefore has an effect of improving the removability of the nanosheet layer 26.

The hydrolyzable silane compound is represented by, for example, SiZ _m W _4-m (m is an integer of 2 to 4, Z is a hydrolyzable group, and W is a non-hydrolyzable group). Compounds. The hydrolyzate of the hydrolyzable silane compound has a structure in which the Si—Z group of SiZ _m W _4-m becomes Si—OH by hydrolysis, and Si—OH can be bonded to the nanosheet surface. The hydrolyzate can bind nanosheets by having two or more Si—OH. Moreover, hydrolyzate may condense and form a condensate.

m is preferably 3 or 4.
The hydrolyzable group of Z is a group that can convert a Si—Z group into a Si—OH group by hydrolysis. Examples of the hydrolyzable group include a halogen atom (for example, a chlorine atom), an alkoxy group, an acyloxy group, an aminoxy group, an amide group, a ketoximate group, a hydroxyl group, an epoxy group, a glycidyl group, and an isocyanate group, and an alkoxy group is particularly preferable. .
The non-hydrolyzable group of W is a functional group whose structure does not change under the condition that the Si—Z group becomes a Si—OH group by hydrolysis. The non-hydrolyzable group is not particularly limited, and may be a known group as a non-hydrolyzable group in a silane coupling agent or the like.

Specific examples of hydrolyzable silane compounds include tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc.), alkoxysilane having an alkyl group (methyltrimethoxysilane, methyltriethoxysilane, Ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, etc.), alkoxysilanes having aryl groups (phenyltrimethoxysilane, phenyltriethoxysilane, etc.) , Alkoxysilane having a perfluoropolyether group (perfluoropolyether triethoxysilane, etc.), alkoxysilane having a perfluoroalkyl group (perfluoro Tiltriethoxysilane, etc.), alkoxysilanes having vinyl groups (vinyltrimethoxysilane, vinyltriethoxysilane, etc.), alkoxysilanes having epoxy groups (2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- Glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, etc.), alkoxysilanes having an acryloyloxy group (3-acryloyloxypropyltrimethoxysilane, etc.), etc. Is mentioned.
Of these, when the nanosheet layer 26 is hydrophilic, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane are preferable. When making the nanosheet layer 26 water-repellent, an alkoxysilane having an alkyl group or an alkoxysilane having a perfluoroalkyl group is preferable.

Hydrolysis of the hydrolyzable silane compound is carried out by using an amount of water that can hydrolyze all hydrolyzable groups of the hydrolyzable silane compound (for example, in the case of tetraalkoxysilane, four times or more moles of water of tetraalkoxysilane) and catalyst. Perform using acid or alkali. Examples of the acid include inorganic acids (HNO ₃ , H ₂ SO ₄ , HCl, etc.) and organic acids (formic acid, oxalic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, etc.). Examples of the alkali include ammonia, sodium hydroxide, potassium hydroxide and the like. The catalyst is preferably an acid from the viewpoint of long-term storage. Moreover, as a catalyst, what does not disturb dispersion | distribution of a nanosheet is preferable.

Examples of the water-soluble polymer include polyvinyl alcohol, polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, polyethylene imine, polydiallyl dimethyl ammonium chloride, sodium polyacrylate, polyacrylamide, polylactic acid, sodium polystyrene sulfonate, sodium polyvinyl sulfate, carboxy Vinyl polymer, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, guar gum, cationized guar gum, carrageenan, sodium alginate, corn starch, xanthan gum, sodium chondroitin sulfate, sodium hyaluronate, starch, modified starch, glue, gelatin, gum arabic, sodium alginate, pectin Etc.
The molecular weight of the water-soluble polymer is preferably 1000 to 100,000. When the molecular weight is less than 1000, the water-soluble polymer is likely to penetrate into the silica-based porous layer 21 and the transmittance is likely to be lowered. When the molecular weight is larger than 100,000, it becomes difficult to dissolve in a solvent, and nanosheets and aggregates are generated in the paint, which may reduce the stability of the paint.

Other ingredients:
The nanosheet layer 26 may contain other components other than the nanosheet and the binder as long as they do not impair the effects of the present invention. Examples of the other components include surfactants that do not modify the surface of the nanosheet, silica fine particles, and titania fine particles. In the case of containing titania fine particles, it is expected that the attached dirt is decomposed by the photocatalytic effect.

By providing the nanosheet layer 26 on the surface of the silica-based porous layer 21, the antifouling property can be improved without deteriorating the antireflection performance.
Since the refractive index of the nanosheet is low and the thickness of the entire nanosheet layer 26 is thin, the antireflection performance of the antifouling antireflection film 20 is hardly affected although it is denser than the porous layer 22.
The nanosheet layer 26 is formed by applying a nanosheet layer-forming coating liquid in which a plurality of nanosheets are dispersed in a liquid medium to the surface of the silica-based porous layer 21 and drying. At that time, the plurality of nanosheets are deposited on the surface of the silica-based porous layer 21. Therefore, the nanosheet layer 26 formed by depositing a plurality of nanosheets is more dense and has higher surface smoothness than the silica-based porous layer 21, so that it is difficult for dirt to enter. Therefore, it is difficult for dirt to adhere.
Since the silica-based porous layer 21 of the present invention has the dense layer 25, the entry of dirt such as EVA can be sufficiently suppressed only by the silica-based porous layer 21. In the present invention, by further forming the nanosheet layer 26, the invasion of dirt such as EVA can be further suppressed, and even if dirt adheres to the surface, a part of the nanosheet is peeled off together with the dirt, leaving a trace of dirt. The effect of being difficult is also obtained.

{Anti-fouling layer}
In the article 1, excellent antifouling performance is exhibited by combining the dense layer 25 and the nanosheet layer 26 in the silica-based porous layer 21.
Hereinafter, the layer composed of the dense layer 25 and the nanosheet layer 26 is referred to as an antifouling layer.

Average layer thickness d1 of the antifouling layer
The average layer thickness d1 of the antifouling layer is 1 to 10 nm, preferably 2 to 7 nm. When the average layer thickness d1 of the antifouling layer is 0.4 nm or more, sufficient antifouling properties can be obtained. If it is more than the said lower limit, sufficient antifouling performance is securable. On the other hand, when it is not more than the above upper limit value, the antifouling layer has little influence on the antireflection performance of the porous layer 22, and the decrease in the maximum transmittance due to the provision of the antifouling layer can be suppressed.
The measuring method of the average layer thickness d1 of the antifouling layer is as shown in the examples described later.

Ratio of the average layer thickness d1 of the antifouling layer to the average layer thickness d2 of the porous layer 22:
The ratio of the average layer thickness d1 of the antifouling layer to the average layer thickness d2 of the porous layer 22 (d1 / d2) is preferably in the range of 0.0013 to 0.5, more preferably 0.005 to 0.00. 25.
If d1 / d2 is not less than the lower limit, sufficient antifouling performance can be ensured. On the other hand, if it is not more than the above upper limit value, sufficient antireflection performance can be ensured. That is, when the ratio of the average layer thickness of the antifouling layer and the silica-based porous layer is within the above range, the antifouling property and the antireflection performance can be sufficiently achieved.

Water contact angle:
The water contact angle of the surface of the antifouling layer, that is, the surface of the antifouling antireflection film 20, is less than 60 °, and preferably less than 50 °. Since the water contact angle on the surface of the antifouling antireflection film 20 is less than 60 °, dirt containing organic matter is less likely to adhere, and the attached dirt is also easily removed, so that the antifouling property is improved. be able to.
The lower limit of the water contact angle on the surface is not particularly limited, but is preferably 30 ° or more, and more preferably 40 ° or more, since adhesion of dirt containing inorganic substances and adhesion of EVA are reduced.
The method for measuring the water contact angle is the same as the method for measuring the “water contact angle” shown in the examples described later.
The water contact angle of the surface of the antifouling antireflection film 20, that is, the surface of the antifouling layer, is determined by the composition of the nanosheet layer 26. Therefore, the water contact angle on the surface of the antifouling layer can be appropriately adjusted depending on the type of nanosheet or the type of surfactant to be added.

Number of holes on the top surface:
When the nanosheet layer 26 does not cover the entire surface of the silica-based porous layer 21, the dense layer 25 becomes the outermost surface of the antifouling antireflection film 20 in a portion where the nanosheet layer 26 does not exist. In that case, the pores 24 in the silica-based porous layer 21 may open on the outermost surface of the antifouling antireflection film 20.
In the present embodiment, the number of holes having an opening diameter of 20 nm or more opened on the outermost surface of the antifouling antireflection film 20 (or the surface of the antifouling layer) (hereinafter, also referred to as “the number of holes on the outermost surface”). ) Is 8 pieces / 10 ⁶ nm ² or less. The number of holes on the outermost surface is preferably 5/10 ⁶ nm ² or less, particularly preferably 0/10 ⁶ nm ² .
The number of holes on the outermost surface is 10 ⁶ nm ² per 10 ⁶ nm ² from the number of holes having an opening diameter of 20 nm or more existing in the region of 900 nm × 900 nm in the image of the surface of the antifouling antireflection film 20 observed by SEM. It is calculated by converting to the number of.

The antifouling antireflection film 20 has not only antifouling properties but also excellent durability because the number of holes on the outermost surface is not more than the above upper limit value or 0/10 ⁶ nm ² .
For example, when a conventional antireflection film is directly formed on the surface of glass as the transparent substrate 10, the porous structure in contact with the transparent substrate 10 under wet heat conditions is broken by the influence of alkali, and the antireflection performance is lowered. To do. On the other hand, even when the antifouling antireflection film 20 is directly formed on the surface of the transparent substrate 10 and is placed under wet heat conditions, the porous structure is maintained over a long period of time, and the antireflection performance is unlikely to deteriorate. . The effect is that the antifouling layer makes it difficult for moisture in the outside air to permeate the silica-based porous layer 21, and the alkali derived from the glass component at the boundary surface between the silica-based porous layer 21 and the transparent substrate 10 that is glass. This is thought to be because it becomes difficult to generate.
In addition, since the outermost surface of the antifouling antireflection film 20 has almost no large-diameter holes and is smooth, the wear resistance is also improved. Further, the antifouling property is improved such that the dirt hardly penetrates into the pores in the film and the attached dirt is easily removed, and the usefulness as an antireflection film is improved.
In addition, there is little influence which the void | hole whose opening diameter is less than 20 nm has on durability. Therefore, the silica-based porous layer 21 may have pores with an opening diameter of less than 20 nm (not shown) in the dense layer 25 and the matrix 23 of the porous layer 22.

{Average reflectance of antifouling antireflection film 20}
The average transmittance (hereinafter also referred to as “average transmittance (0 ° incidence)”) of light having a wavelength of 400 to 1100 nm incident on the surface of the article 1 on the antifouling antireflection film 20 side at an incidence angle of 0 ° is referred to as “average transmittance (0 ° incidence)”. It is preferably 94.0% or more, more preferably 94.2% or more. If the average transmittance (0 ° incidence) of the article 1 is equal to or higher than the lower limit, the light transmittance required for a cover glass of a solar cell is sufficiently satisfied.
The average transmittance of an article using another translucent substrate instead of the transparent base material 10 in the article 1 is preferably 94.0% or more as described above.

The average reflectance of light having a wavelength of 400 to 1100 nm incident on the surface of the article 1 on the antifouling antireflection film 20 side at an incident angle of 5 ° (hereinafter, also referred to as “average reflectance (5 ° incidence)”). It is preferably 2.0% or less, and more preferably 1.7% or less. When the average reflectance (5 ° incidence) of the antifouling antireflection film 20 is not more than the above upper limit value, the antireflection performance required for a cover glass of a solar cell is sufficiently satisfied.
The incident angle in this specification is an angle formed by the incident direction of light and the normal line of the antifouling antireflection film 20.

(Method for manufacturing article 1)
Article 1 includes a step of applying a coating liquid for forming a silica-based porous layer containing a matrix precursor (A), particles (B), and a liquid medium (C) on a transparent substrate, and heat treatment. A step of forming a silica-based porous layer comprising a step of forming a matrix from a matrix precursor (A) and a step of removing the particles (B) before and after the heat treatment, or before or during the heat treatment , “First step”) and a step of applying a nanosheet layer forming coating solution on the surface of the silica-based porous layer and drying to form a nanosheet layer (hereinafter referred to as “second step”). ).
In the first step, a coating solution for forming a silica-based porous layer containing a matrix precursor (A), particles (B1) that can be removed by heat treatment, and a liquid medium (C) is formed on a transparent substrate. A step of forming a silica-based porous layer, which includes a step of applying and a step of forming a matrix from the matrix precursor (A) by heat treatment and removing the particles (B1), is preferable.

{First step}
The first step is a step of forming the silica-based porous layer 21 on the transparent substrate 10.
In the formation of the silica-based porous layer 21, first, a silica-based porous layer forming coating solution containing a matrix precursor (A), particles (B), and a liquid medium (C) shown below is used. It is applied to the surface of the transparent substrate 10 and heat-treated.
The matrix 23 is formed from the matrix precursor (A) by heat-treating the coating film of the silica-based porous layer forming coating solution.
If the particles (B) can be removed by heat treatment, the particles (B) are removed by the heat treatment, and the silica-based porous layer 21 is formed. Specifically, when the particles (B) are composed of a thermally decomposable material (for example, a thermally decomposable organic polymer), the heat treatment temperature when forming the matrix 23 is set to the thermal decomposition of the thermally decomposable material. By setting the temperature to be equal to or higher than the temperature, the particles (B) are vaporized after being decomposed, pass through fine pores in the matrix 23, and discharged to the outside of the matrix 23, thereby forming the silica-based porous layer 21. The heat treatment for forming the matrix 23 may be performed at a temperature lower than the thermal decomposition temperature, and after the film formation, the heat treatment may be performed again at a temperature equal to or higher than the thermal decomposition temperature.
When the particles (B) are not removed by the heat treatment, the silica-based porous layer 21 is subjected to a removal treatment according to the material constituting the particles (B) before or after the formation of the matrix 23 by the heat treatment. Can be formed.

Matrix precursor (A):
The matrix precursor (A) includes a compound (a1) represented by the following general formula (a1), at least one compound (A1) selected from the hydrolyzate and partial condensate thereof, and the following general formula (a2) And at least one compound (A2) selected from the hydrolyzate and partial condensate thereof.
SiX ₄ (a1)
Y _n SiX _4-n (a2)
[Wherein, X represents a hydrolyzable group, Y represents a non-hydrolyzable group in which the dielectric constant of Y-OH is 35 F / m or less, and n represents an integer of 1 to 3. ]

In formula (a1), X represents a hydrolyzable group. The hydrolyzable group is a group that can convert a Si—X group into a Si—OH group by hydrolysis.
Examples of X include halogen atoms (for example, chlorine atoms), alkoxy groups, acyloxy groups, aminoxy groups, amide groups, ketoximate groups, hydroxyl groups, epoxy groups, glycidyl groups, isocyanate groups, and the like. An alkoxy group is particularly preferable because the hydrolysis polycondensation reaction can be easily controlled. As an alkoxy group, a C1-C4 alkoxy group is preferable and a methoxy group or an ethoxy group is more preferable.
Four Xs which compound (a1) has may be the same or different. The same group is preferable in terms of availability, ease of controlling the hydrolysis polyaggregation reaction, and the like.

Specific examples of the compound (a1) include, for example, tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc.) and the like. These may be used alone or in combination of two or more.
In the production method of the present invention, it is considered that the dense layer 25 is formed by causing phase separation by using two or more kinds of matrix precursors (compounds (A1) and (A2)) having different dielectric constants (polarities). It is done. Therefore, it is considered that the larger the dielectric constant difference between the compound (A1) having a large dielectric constant and the compound (A2) having a small dielectric constant, the more the phase separation is caused, and the dense layer 25 becomes thicker. When the hydrolyzable group possessed by the compound (a1) is an alkoxy group, the smaller the carbon number of the alkoxy group, the faster the hydrolysis proceeds and the easier the conversion to Si—OH. As a result, the dielectric constant of the compound (A1) is increased (dielectric constant: Si—X <Si—OH), and thus phase separation from the compound (A2) having a small dielectric constant is remarkably caused, so that the dense layer The layer thickness of 25 tends to be thick.
Therefore, the compound (a1) is preferably tetraalkoxysilane having 1 or 2 carbon atoms in the alkoxy group among tetraalkoxysilanes, and particularly preferably tetramethoxysilane or tetraethoxysilane.

The hydrolyzate and partial condensate of compound (a1) can be obtained by a conventional method.
The compound (a1) has high reactivity, and a hydrolysis reaction or a partial condensation reaction can proceed only by adding water to the compound (a1). Therefore, a hydrolyzate or a partial condensate can be obtained by mixing the compound (a1) and water.
The amount of water added is preferably at least 4 moles of the compound (a1).
At this time, it is preferable to add a catalyst together with water. An acid or an alkali can be used as the catalyst. Examples of the acid include inorganic acids (such as nitric acid, sulfuric acid, and hydrochloric acid) and organic acids (such as formic acid, oxalic acid, monochloroacetic acid, dichloroacetic acid, and trichloroacetic acid). Examples of the alkali include ammonia, sodium hydroxide, potassium hydroxide and the like. The catalyst is preferably an acid from the viewpoint of long-term storage stability of the hydrolyzate or partial condensate of compound (a1).
The obtained reaction liquid is usually used as it is or after being appropriately diluted to prepare the coating liquid for forming the silica-based porous layer. Therefore, the catalyst used for the hydrolysis is preferably one that does not hinder the dispersion of the particles (B).
5-80 degreeC is preferable and, as for the temperature at the time of hydrolyzing a compound (a1) and performing partial polycondensation reaction, 10-70 degreeC is more preferable. If it is more than the said lower limit, hydrolysis polycondensation reaction will fully advance, and if it is below the said upper limit, hydrolysis polycondensation reaction control is easy.

In formula (a2), n represents an integer of 1 to 3, preferably 1 or 2, and particularly preferably 1.
Examples of the hydrolyzable group for X include the same groups as described above.
When n is 1 or 2, the plurality of Xs that the compound (a2) has may be the same or different. The same group is preferable in terms of availability, ease of controlling the hydrolysis reaction, and the like.

Y shows the non-hydrolyzable group whose dielectric constant of Y-OH is 35 F / m or less.
The non-hydrolyzable group is a functional group whose structure does not change under the condition that the Si—X group becomes a Si—OH group by hydrolysis.
Originally, the dielectric constant of Si (OH) ₄ which is a hydrolyzate and partial condensate of compound (a1) and the hydrolyzate and partial condensate Y _n Si (OH) _4-n of compound (a2) will be discussed. Although it should be difficult to measure the dielectric constant of the hydrolyzate and partial condensate itself of each compound. Therefore, the dielectric constant of similar compounds was applied and modeled for verification. Specifically, HO-OH (hydrogen peroxide) as a similar compound of the hydrolyzate and partial condensate Si-OH of compound (a1), and Y-OH as the hydrolyzate and partial condensate of compound (a2). Selected. As a result, it was found that if the dielectric constant difference between HO—OH and Y—OH is large, phase separation is caused and the dense layer 25 is easily formed.

A literature value may be used for the dielectric constant of Y—OH, but it can be measured by the following measurement method.
The dielectric constant of Y-OH conforms to the provisions of JIS-R1627, and an electric field is applied to the sample by a bridge circuit using a network analyzer (manufactured by Agilent Technologies, PNA microwave vector network analyzer). The coefficient and phase were calculated from the measured values.

  Examples of Y include a perfluoropolyether group, a perfluoroalkyl group, an alkyl group, and an aryl group (such as a phenyl group).

In addition, as shown below, there exists a tendency for the dielectric constant of Y-OH to become so small that the chain length of a hydrocarbon group is long or the number of the fluorine atoms which substitute the hydrogen atom of a hydrocarbon group is large. On the other hand, most of the hydrolyzate of compound (a1) is Si—OH, and the dielectric constant of HO—OH (hydrogen peroxide) is 89.2 F / m.
[Similar to Compound (a1)]
HO-OH (hydrogen peroxide: dielectric constant 89.2 F / m).
[Similar to Compound (a2)]
CH ₃ -OH (methanol: permittivity 33.1F / m).
CH ₃ CH ₂ -OH (ethanol: permittivity 23.8F / m).
_{CH 3 (CH 2) 5 -OH} (1- hexanol dielectric constant 13.3F / m).
C ₆ H ₅ -OH (phenol: permittivity 2.9F / m).
CF ₃ CH ₂ -OH (trifluoroethanol: permittivity 2.1F / m).

Specific examples of the compound (a2) include, for example, monoalkyltrialkoxysilane (methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, etc.), Dialkyl dialkoxysilane (dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane, etc.), trialkylmonoalkoxysilane (trimethylmethoxysilane, trimethylethoxysilane, Triethylmethoxysilane, triethylethoxysilane, tripropylmethoxysilane, tripropylethoxysilane), monoaryltrialkoxysilane ( Phenyltrimethoxysilane, phenyltriethoxysilane, etc.), diaryl dialkoxysilane (diphenyldimethoxysilane, diphenyldiethoxysilane, etc.), triarylmonoalkoxysilane (triphenylmethoxysilane, triphenylethoxysilane, etc.), perfluoropolyether group Alkoxysilane (perfluoropolyether triethoxysilane, etc.) having a perfluoroalkyl group, alkoxysilane having a perfluoroalkyl group (perfluoroethyltriethoxysilane, etc.), silicone oil (dimethyl silicone oil, methyl hydrogen silicone oil, methylphenyl silicone oil, cyclic dimethyl) Silicone oil, etc.). These may be used alone or in combination of two or more.
As the compound (a2), monoalkyltrialkoxysilanes and monoaryltrialkoxysilanes are preferable and monoaryltrialkoxysilanes are more preferable because they are easily available and do not generate an inert gas during thermal decomposition.

  The hydrolyzate and partial condensate of compound (a2) can be obtained in the same manner as the hydrolyzate and partial condensate of compound (a1). Further, the compounds (a1) and (a2) may be mixed in advance to perform a cohydrolysis polycondensation reaction.

In the matrix precursor (A), the ratio of the content of the compound (A1) and the compound (A2) is converted into the molar ratio ((a1) / (a2)) of the compound (a1) and the compound (a2). And within the range of 5 to 60, and preferably within the range of 10 to 30.
By setting the value of (a1) / (a2) to be equal to or less than the above upper limit value, the dense layer 25 is formed with a sufficient thickness, and the number of the outermost surface openings of the antifouling layer is 8/10 ⁶ nm ² or less. can do. Since the number of holes on the outermost surface is small, it is difficult for dirt to adhere, and excellent moisture resistance and dirt removability can be obtained. On the other hand, by setting the value of (a1) / (a2) to the lower limit value or more, the dense layer 25 becomes hydrophilic after the heat treatment performed in the first step. It becomes easy to form the nanosheet layer 26 uniformly.

  The average molecular weight of the hydrolyzate and partial condensate of compound (a1), (a2), or the cohydrolyzate and partial condensate of (a1) and (a2) is preferably in the range of 200 to 2000, and 300 to 1500. The range of is more preferable. If the average molecular weight is not less than the lower limit, volatilization of unreacted components can be suppressed, and if it is not more than the upper limit, sufficient transparency can be ensured. The average molecular weight can be controlled by the amount of water added, the reaction temperature, the content of the matrix precursor (A), and the like. The average molecular weight is a polystyrene-reduced weight average molecular weight measured by gel permeation chromatography (GPC).

The content of the matrix precursor (A) in the silica-based porous layer forming coating solution is not particularly limited as long as the silica-based porous layer forming coating solution can be applied, but the silica-based porous layer is not limited. The SiO ₂ equivalent solid content concentration is preferably 0.2 to 20% by mass and more preferably 0.5 to 15% by mass with respect to the total amount (100% by mass) of the forming coating solution. If it is 0.2% by mass or more, hydrolysis polycondensation reaction proceeds sufficiently, and if it is 20% by mass or less, hydrolysis polycondensation reaction control is easy and long-term storage stability is good.
Incidentally, SiO ₂ in terms of solids are solids when all the Si matrix precursor contained in the silica-based porous layer forming coating solution (A) was converted to SiO _2.

Particle (B):
The particles (B) are particles that can be removed from the matrix precursor (A) or the matrix.
The particles (B) are removed before or after or during the heat treatment when the matrix is formed from the matrix precursor (A) after the silica-based porous layer forming coating solution is applied on the transparent substrate. Examples of the method for removing the particles (B) include heat treatment, plasma treatment, solvent immersion, acid or alkali immersion, and light irradiation.
Examples of particles that can be removed from the matrix precursor (A) or the matrix include particles (B1) that can be removed by heat treatment, particles (B2) that can be removed by plasma treatment, and particles (B3) that can be removed by solvent immersion. , Particles (B4) removable by acid or alkali immersion, particles (B5) removable by light irradiation, and the like. Among these, particles (B1) that can be removed by the heat treatment that can be removed by the heat treatment simultaneously with the heat treatment for forming the matrix from the matrix precursor (A) are preferable.

Examples of the particles (B1) that can be removed by heat treatment include particles made of a thermally decomposable material or a thermally sublimable material.
100-800 degreeC is preferable and, as for the thermal decomposition temperature of a thermally decomposable material, 200-700 degreeC is more preferable.
Examples of the thermally decomposable material include carbon, organic polymer, and surfactant micelle. Among these, carbon or an organic polymer is preferable from the viewpoint of stability over time.
The thermal decomposition temperature of carbon in air is about 500 ° C. The thermal decomposition temperature of the organic polymer in air varies depending on the type and molecular weight of the organic polymer, but is generally about 200 to 600 ° C. The thermal decomposition temperature of the organic polymer can be measured by differential thermal-thermogravimetric simultaneous measurement (TG-DTA).
The particles that can be removed by the heat treatment may be core-shell particles coated with an inorganic oxide such as SiO ₂ that is not removed by the heat treatment. When the thickness of the shell is thick, irregularities derived from particles are likely to be formed on the film surface, and the shell thickness is preferably 5 nm or less because insufficient wear resistance and dirt are likely to adhere. From the viewpoint of antireflection performance, it is more preferable that a component that cannot be removed by heating is not included.

The organic polymer is not particularly limited as long as synthesis of nanoparticles having a desired particle size can be obtained, but (meth) acrylic monomers, styrene monomers, diene monomers, imide monomers, amide monomers. Homopolymers or copolymers of monomers selected from the group consisting of (hereinafter also referred to as “specific monomer group”) are preferred.
Acrylic monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, (meth ) Pentyl acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, ( (Meth) acrylic acid dodecyl, (meth) acrylic acid phenyl, (meth) acrylic acid methoxyethyl, (meth) acrylic acid ethoxyethyl, (meth) acrylic acid propoxyethyl, (meth) acrylic acid butoxyethyl, (meth) acrylic acid Ethoxypropyl, diethylaminoethyl (meth) acrylate , Dialkylaminoalkyl (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide, diacetone acrylamide, glycidyl (meth) acrylate, ethylene glycol diacrylate, diethyl glycol diacrylate, triethylene glycol Diacrylic acid ester, polyethylene glycol diacrylic acid ester, dipropylene glycol diacrylic acid ester, tripropylene glycol diacrylic acid ester, ethylene glycol dimethacrylic acid ester, diethylene glycol dimethacrylic acid ester, triethylene glycol dimethacrylic acid ester , Polyethylene glycol diacrylate, propylene glycol dimethacrylate , Dimethacrylates of dipropylene glycol, dimethacrylate ester of tripropylene glycol.
Examples of styrene monomers include alkyl styrene; styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, octyl styrene, fluorostyrene, chloro. Examples include styrene, bromostyrene, dibromostyrene, chloromethylstyrene, nitrostyrene, acetylstyrene, methoxystyrene, α-methylstyrene, vinyltoluene, sodium p-styrenesulfonate, and the like.
Examples of the diene monomer include butadiene, isoprene, cyclopentadiene, 1,3-pentadiene, dicyclopentadiene, and the like.
Examples of the imide monomers include maleimide, N-methylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide, 6-aminohexyl succinimide, 2-aminoethyl succinimide, and the like.
Examples of amide monomers include acrylamide derivatives such as acrylamide and N-methylacrylamide, allylamine derivatives such as N, N-dimethylacrylamide and N, N-dimethylaminopropylacrylamide, and acrylamide derivatives such as acrylamide and N-methylacrylamide. And aminostyrenes such as N-aminostyrene.

When the organic polymer is a copolymer of a monomer selected from the specific monomer group, the copolymer may be a copolymer of two or more monomers selected from the specific monomer group. In addition, at least one selected from the specific monomer group and at least one monomer other than the monomer selected from the specific monomer group may be copolymerized.
Examples of the other monomers include divinylbenzene, vinyl acetate, vinylpyridine, acrylic acid, methacrylic acid, tetrahydrophthalic acid, maleic acid, itaconic acid, fumaric acid, citraconic acid, crotonic acid, isocrotonic acid, norbornene dicarboxylic acid, methylene Malonic acid, monoethyl itaconate, monobutyl itaconate, monomethyl maleate, monoethyl maleate, monobutyl maleate, monopropyl maleate, monooctyl maleate, carboxyalkyl vinyl ether, carboxyalkyl vinyl ester, bicyclo [2,2,1] Hept-2-ene-5,6-dicarboxylic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid Acrylic acid such as anhydride, aminoethyl (meth) acrylate, propylaminoethyl (meth) acrylate, dimethylaminoethyl methacrylate, aminopropyl (meth) acrylate, phenylaminoethyl methacrylate, cyclohexylaminoethyl methacrylate, or Alkyl ester derivatives of methacrylic acid, vinylamine derivatives such as N-vinyldiethylamine, N-acetylvinylamine, allylamine, methacrylamine, N-methylacrylamine, N, N-dimethylacrylamide, N, N-dimethylaminopropylacrylamide Allylamine derivatives such as phenyl (meth) acrylate, benzyl (meth) acrylate, vinyl salicylate, vinylidene chloride, vinyl chlorohexanecarboxylate, 2-chloroethyl acrylate 2-chloroethyl methacrylate, acrylonitrile, methacrylonitrile, methacrylamide, N-methylol methacrylamide, N-methoxyethyl methacrylamide, N-butoxymethyl methacrylamide, aminoethyl (meth) acrylate, (meth) acrylic acid Propylaminoethyl, dimethylaminoethyl methacrylate, aminopropyl (meth) acrylate, phenylaminoethyl methacrylate, cyclohexylaminoethyl methacrylate, alkyl ester derivatives of acrylic acid or methacrylic acid, N-vinyldiethylamine, N-acetylvinyl Vinylamine derivatives such as amines, allylamine, methacrylamine, N-methylacrylamine, N, N-dimethylacrylamide, N, N-dimethylaminopropylacrylate Allylamine derivatives such as amide, acrylamide derivatives such as acrylamide and N-methylacrylamide, p-aminostyrene, N-methylol (meth) acrylamide and diacetone acrylamide, 6-aminohexyl succinimide, 2-aminoethyl succinic acid Imido, glycidyl methacrylate, mono and diglycidyl esters of maleic acid, mono and diglycidyl esters of fumaric acid, mono and diglycidyl esters of crotonic acid, mono and diglycidyl esters of tetrahydrophthalic acid, mono and glycidyl esters of itaconic acid Mono- and diglycidyl esters of butenetricarboxylic acid, mono- and diglycidyl esters of citraconic acid, mono- and diglycidyl esters of allyl succinic acid, etc. Alkyl glycidyl ester, alkyl glycidyl ester of p-styrene carboxylic acid, allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, acrylate-2-ethylglycidyl acrylate, methacrylate-2-ethylglycidyl methacrylate Ether, 2-methylallyl glycidyl ether, styrene-p-glycidyl ether, glycidyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, acrylic acid or Monoesters of methacrylic acid and polypropylene glycol or polyethylene glycol, adducts of lactones and 2-hydroxyethyl (meth) acrylate, trifluoromethyl (meth) acrylate (Meth) acrylic acid-2-trifluoromethylethyl, (meth) acrylic acid-2-perfluoromethylethyl, (meth) acrylic acid-2-perfluoroethyl-2-perfluorobutylethyl, (Meth) acrylic acid-2-perfluoroethyl, (meth) acrylic acid perfluoromethyl, (meth) acrylic acid diperfluoromethyl methyl, vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl isobutyrate, Vinyl pivalate, vinyl caproate, vinyl persuccinate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pt-butylbenzoate, vinyl salicylate, vinylidene chloride, vinyl chlorohexanecarboxylate, acrylic acid-2 -Chloroethyl, 2-chloroethyl methacrylate, 3-chloro-2-hydroxy Cypropyl methacrylate, β-methacryloyloxyethyl hydrogen phthalate, phenoxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene Glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1, 1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-trishi B carboxymethyl propane triacrylate, N- methylolacrylamide acrylamide and the like.
In the copolymer, the proportion of monomer units selected from the specific monomer group is preferably 80 mol% or more, particularly preferably 100 mol%, based on the total of all monomer units.

200-600 degreeC is preferable and, as for the thermal decomposition temperature of the said homopolymer or copolymer, 300-500 degreeC is more preferable.
As the organic polymer, in addition to the homopolymer or copolymer of the specific monomer group, polyethylene glycol, polypropylene glycol, polyisobutylene glycol, polyethylene oxide-polypropylene oxide diblock polymer, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock A polymer, polyvinyl alcohol, silicone or the like can also be used.

The particles (B2) that can be removed by the plasma treatment can be decomposed and removed by irradiating the film made of the matrix precursor (A) and the particles (B) with plasma. Examples of the material of the particles (B) include the organic polymers described above.
The particles (B3) that can be removed by immersion in the solvent can be dissolved and removed by immersing a film composed of the matrix precursor (A) and the particles (B) in the solvent. Examples of the material of the particles (B) include diglyme, N, N-dimethylformamide, N, N-dimethylacetamide, ethyl acetate, ethyl acetoacetate, N-methyl-2-pyrrolidinone, 2-pyrrolidinone, 1,3. -Soluble in solvents such as dimethyl-2-imidazolidinone, dimethyl sulfoxide, toluene, xylene, benzene, trichlene, mineral spirits, benzol, xylol, γ-butyrolactone, tetrahydrofuran, methyl ethyl ketone, acetone, dichloromethane, chloroform, methylene chloride Examples thereof include polystyrene and polymethyl acrylate.
The particles (B4) that can be removed by acid or alkali immersion can be dissolved and removed by immersing the film made of the matrix precursor (A) and the particles (B) in acid or alkali. Examples of the material of the particles include zinc oxide, basic zinc carbonate, calcium carbonate and the like which can be dissolved in acids such as hydrochloric acid, nitric acid, and sulfuric acid. Zinc oxide etc. are mentioned as what melt | dissolves in alkalis, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and ammonia.
The particles (B5) that can be removed by light irradiation can be removed by irradiating the film composed of the matrix precursor (A) and the particles (B) with light (for example, ultraviolet rays) and dissolving them. Examples of the material of the particles include zinc oxide and cadmium sulfide.
When the particles (B) are removed by the plasma treatment, solvent immersion, acid or alkali immersion, or light irradiation, heat treatment is performed before and / or after the step of removing the particles (B) in order to form the dense layer 25. Is preferred.

The particles (B) are preferably made of a thermally decomposable material in that the particles (B) can be removed simultaneously with the heat treatment when the matrix precursor (A) is used as a matrix, and the production process becomes simple. . Especially, it is preferable to consist of carbon or an organic polymer at the point of thermal decomposition temperature. That is, the particles (B) are preferably carbon particles or organic polymer particles.
As a carbon particle, a commercially available thing may be used and what was manufactured by the manufacturing method of a well-known carbon nanoparticle may be used.
As an organic polymer particle, a commercially available thing may be used and what was manufactured by the manufacturing method of a well-known organic polymer nanoparticle may be used. For example, a dispersion in which organic polymer nanoparticles are dispersed can be obtained by a known emulsion polymerization method. Specifically, an aqueous dispersion of organic polymer nanoparticles can be obtained by adding a monomer to water containing a surfactant, mixing to form micelles, and adding a polymerization initiator for polymerization. Moreover, you may use the organic polymer nanoparticle obtained by the soap free polymerization method which does not use surfactant.

The average primary particle diameter of the particles (B) is 20 to 130 nm, and preferably 30 to 100 nm. When the average primary particle diameter of the particles (B) is 20 nm or more, a silica-based porous layer having pores with an opening diameter of 20 nm can be formed, and when the average primary particle diameter is 130 nm or less, the number of open pores on the outermost surface is 8/10 It can be ⁶ nm ² or less. Further, when the average primary particle diameter of the particles (B) is in the range of 20 to 130 nm, the average opening diameter tends to be in the range of 15 to 100 nm.
The average primary particle size in this specification is 100 particles randomly selected from an image obtained by observation with a transmission electron microscope, the particle size of each particle is measured, and the particle size of 100 particles is determined. It is average.

As the particles (B), one type may be used alone, or two or more types having different materials and average primary particle diameters may be used in combination.
The content of the particles (B) in the silica-based porous layer forming coating solution is the mass ratio of the solid content of the matrix precursor (A) in terms of SiO ₂ and the content of the particles (B) (( A) / (B)) is preferably in an amount in the range of 0.3 to 4.0, and more preferably in an amount in the range of 0.5 to 3.0.
When (A) / (B) is not more than the above upper limit value, the porosity in the silica-based porous layer 21 is sufficiently high, and the refractive index of the silica-based porous layer 21 is sufficiently low (eg, 1.38). The following). When (A) / (B) is equal to or more than the lower limit, the porosity in the silica-based porous layer 21 does not become too high, and it is easy to form independent pores and is excellent in durability.

Liquid medium (C):
The liquid medium (C) is a liquid in which the matrix precursor (A) is dissolved and the particles (B) are dispersed. The liquid medium (C) is a mixed liquid in which two or more kinds of liquids are mixed. Also good.
Since water is required for hydrolysis of the compounds (a1) and (a2), the liquid medium (C) preferably contains at least water.
Water and other liquids may be used in combination. Examples of the other liquid include alcohols (methanol, ethanol, isopropanol, butanol, diacetone alcohol, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ethers (tetrahydrofuran, 1,4-dioxane, etc.). ), Cellosolves (methyl cellosolve, ethyl cellosolve, etc.), esters (methyl acetate, ethyl acetate, etc.), glycol ethers (ethylene glycol monoalkyl ether, etc.), nitrogen-containing compounds (N, N-dimethylacetamide, N, N -Dimethylformamide, N-methylpyrrolidone, etc.), sulfur-containing compounds (dimethylsulfoxide, etc.) and the like.
Among the other liquids, as the solvent for the matrix precursor (A), alcohols are preferable, and methanol, ethanol, and isopropanol are particularly preferable.
Among the other liquids, any of alcohols, ketones, ethers, cellosolves, esters, glycol ethers, nitrogen-containing compounds, sulfur-containing compounds, etc. may be used as the dispersion medium for the particles (B). Good.

The coating liquid for forming a silica-based porous layer may contain components other than the matrix precursor (A) and the particles (B) as long as the effects of the present invention are not impaired.
Examples of the other component include a curing catalyst (metal chelate, metal alcoholate, organotin, etc.) for improving the reactivity of the matrix precursor (A).

Method for preparing silica-based porous layer forming coating solution:
Examples of the method for preparing a coating liquid for forming a silica-based porous layer include a method of mixing a solution of a matrix precursor (A) and a dispersion of particles (B), and more specifically, the following method (Α) to (γ) may be mentioned. Among these, the method (β) is preferable because the compound (a2) easily moves to the surface of the coating film when the silica-based porous layer forming coating solution is applied to the surface of the transparent substrate 10. Moreover, it is preferable to add the dispersion liquid of particle | grains (B), after diluting the solution of a matrix precursor from the point which suppresses aggregation of particle | grains (B).

(Α) A method in which the compound (a1) and the compound (a2) in the solution are hydrolyzed, diluted with a solvent as necessary, and then a dispersion of particles (B) is added.
(Β) After hydrolyzing the compound (a1) in the solution (preferably after elapse of 2 hours or more after hydrolysis), a solution of the compound (a2) is added, diluted with a solvent as necessary, and then particles ( A method of adding the dispersion of B).
(Γ) A method in which the compound (a1) in the solution is hydrolyzed, diluted with a solvent, a solution of the compound (a2) is added, and then a dispersion of the particles (B) is added.

Application method:
As a coating method of the coating liquid for forming the silica-based porous layer, known wet coating methods (spin coating method, spray coating method, dip coating method, die coating method, curtain coating method, screen coating method, ink jet method, flow coating method) , Gravure coating method, bar coating method, flexo coating method, slit coating method, roll coating method, sponge coating method, etc.) can be used.
10-100 degreeC is preferable and, as for application | coating temperature (base material), 20-80 degreeC is more preferable.

Heat treatment:
What is necessary is just to determine the heat processing temperature (base material) suitably according to the transparent base material 10, particle | grains (B), or a matrix precursor (A).
In order to use the matrix precursor (A) as the matrix 23, heat treatment may be performed at 80 ° C. or higher, but 100 ° C. or higher is preferable, and 200 to 700 ° C. is more preferable. If heat processing temperature (base material) is more than the said lower limit, the matrix 23 will be densified and durability will improve. If heat processing temperature (base material) is below the said upper limit, since alkali diffusion from glass can be restrained low, moisture resistance is favorable.
When the particles (B) are composed of a thermally decomposable material such as carbon or an organic polymer, and the particles (B) are removed by heat treatment, the heat treatment is performed at a temperature equal to or higher than the thermal decomposition temperature of the thermally decomposable material. The particles (B) can be removed. In this case, the heat treatment temperature is preferably (thermal decomposition temperature + 100 ° C.) or higher, more preferably (thermal decomposition temperature + 50 ° C.) or higher.
When the particles (B) are removed by heat treatment, heat treatment for making the matrix precursor (A) into the matrix 23 may be performed at a temperature lower than the thermal decomposition temperature before the heat treatment.
The heat treatment may also serve as a step of strengthening the glass. When using glass for solar cell applications, tempered glass is used from the viewpoint of safety. The tempered glass has a compressive stress on the surface, has a higher strength than a general float plate glass, and is excellent in safety because it becomes granular even when broken. As a technique for strengthening the glass, a heat strengthening method in which the glass is heated to 600 to 700 ° C. and then rapidly cooled by blowing air onto the surface, and a glass containing sodium ions is melted at 300 to 500 ° C. containing potassium ions. The chemical strengthening method which ion-exchanges on the glass surface by impregnating with salt is mentioned.

When the particles (B) cannot be removed by the heat treatment, the particles (B) are removed by a method other than the heat treatment before or after the heat treatment.
Examples of the removal method other than the heat treatment include plasma treatment, solvent immersion, acid or alkali immersion, and light irradiation as mentioned in the description of the particles (B). Specifically, a method of irradiating a film comprising a matrix precursor (A) and particles (B) with plasma, a method of immersing the film in a solvent, a method of immersing the film in an acid or an alkali, the film And a method of irradiating with light.
In terms of simplicity in the production process, it is preferable to use particles (B) made of a thermally decomposable material such as carbon and organic polymer, and remove the particles (B) by heat treatment.

In the production method described above, the silica-based porous layer forming coating solution is applied onto the transparent substrate 10, preheated as necessary, heat treated, and particles (B) are removed. By performing once, a two-layer structure in which the distribution state of the holes 24 is different (the dense layer 25 in which the holes 24 having a diameter of 20 nm or more do not exist, and the holes 24 having a diameter of 20 nm or more on the glass substrate 12 side of the dense layer 25. A silica-based porous layer 21 having an existing porous layer 22) can be formed.
This is considered to be due to the following reason.

The dielectric constant of HO—OH is 89.2 F / m with respect to the Si—OH group. By having Y in Y—OH having a smaller dielectric constant than this, the interface free energy of the hydrolyzate or partial condensate of compound (a2) is the hydrolyzate of compound (a1) (Si (OH) ₄ ). Or lower than the interfacial free energy of the partial condensate.
Therefore, when a silica-based porous layer forming coating solution containing the compound (A1) and the compound (A2) is applied to the surface of a transparent substrate such as a glass plate, the compound (A2) floats in the coating film, The phases are separated into an upper phase (compound (A2) phase) and a lower phase (compound (A1) phase). Since the particles (B) have an average primary particle size that is somewhat large, they do not float and remain on the lower phase side as they are. Therefore, by subjecting the coating film to heat treatment, the compounds (A1) and (A2) are used as matrices, respectively, and subjected to removal treatment according to the material of the particles (B) simultaneously with the heat treatment or before or after the heat treatment. A silica-based porous layer 21 having pores 24 having a shape corresponding to the shape of (B) is formed.

  For this reason, in the silica-based porous layer 21 formed as described above, the dense layer 25 and the porous layer 22 are considered to have different compositions in the matrix 23. That is, the matrix 23 constituting the dense layer 25 is substantially made of a heat-treated product of the compound (A2) and includes a structure derived from the compound (A2) (for example, a non-hydrolyzable group Y). The matrix 23 constituting the porous layer 22 is substantially composed of a heat-treated product of the compound (A1), and does not include or includes very little structure derived from the compound (A2).

In order to make it easier to apply the nanosheet layer forming coating solution in the second step to be described later, it is preferable that the water contact angle on the surface of the silica-based porous layer 21 be 50 ° or less.
The water contact angle on the surface of the silica-based porous layer 21 can be set by adjusting the components of the matrix 23 constituting the dense layer 25, the content thereof, and the like. For example, among the compounds to be included in the coating liquid for forming a silica-based porous layer, if the type and blending amount of the compound (A2) are adjusted, the water contact angle on the surface of the silica-based porous layer should be 50 ° or less. Can do.
Specifically, the concentration of the compound (A) blended in the coating liquid for forming a silica-based porous layer is preferably 5% by mass or less with respect to the total solid content in the coating liquid. On the other hand, in order to sufficiently form the dense layer 25, the content is preferably 2% by mass or more.

  According to the above first step, the refractive index of the formed silica-based porous layer 21 can be set to 1.38 or less. The lower the refractive index, the lower the reflectance and the better the antireflection performance.

{Second step}
In the second step, a coating liquid for forming a nanosheet layer containing a plurality of nanosheets and a dispersion medium of the nanosheets is formed on the surface of the silica-based porous layer 21 formed on the surface of the transparent substrate 10 in the first step. The nanosheet layer 26 is formed by applying and drying. Thereby, the article 1 is obtained.
The coating solution for forming a nanosheet layer contains a plurality of nanosheets and a dispersion medium for the nanosheets.

Nanosheet:
The description of the nanosheet is the same as described above.
As the nanosheet, a layered product of a layered compound such as a commercially available layered polysilicate or layered clay mineral may be used, or one manufactured by a known manufacturing method may be used.
The nanosheet can be obtained, for example, by peeling off a layer constituting the natural or synthetic inorganic layered compound by a conventional method. For example, a nanosheet dispersion liquid in which nanosheets are dispersed in water can be obtained by adding an inorganic layered compound to water to swell and stirring. Moreover, as an inorganic layered compound, in order to enhance the dispersibility in a solvent, a compound whose surface or interlayer is previously treated with a surfactant or the like may be used.
The nanosheet dispersion can be used as it is as a coating solution for forming a nanosheet layer or for preparing a coating solution for forming a nanosheet layer. For example, a coating liquid for forming a nanosheet layer can be prepared by mixing a nanosheet dispersion and a solution of an optional component (such as a binder or a precursor thereof). Moreover, you may collect | recover nanosheets from a nanosheet dispersion liquid, and use it for preparation of the coating liquid for nanosheet layer formation.

  In the nanosheet layer forming coating solution, the content of the nanosheet is not particularly limited as long as the nanosheet layer forming coating solution can be applied, but with respect to the total amount (100% by mass) of the nanosheet layer forming coating solution, 0.05-0.50 mass% is preferable, and 0.10-0.35 mass% is more preferable. If the content of the nanosheet is equal to or more than the lower limit, an arbitrary component dissolved in the nanosheet layer forming coating liquid is less likely to penetrate into the silica-based porous layer 21 when the nanosheet layer forming coating liquid is applied. If the content of the nanosheet is less than or equal to the above upper limit value, the coating property of the coating liquid for forming the nanosheet layer is good, the thin nanosheet layer 26 can be formed, and the uniformity of the layer thickness of the nanosheet layer 26 to be formed is also good. is there.

Dispersion medium:
The dispersion medium is a liquid that disperses the nanosheet. When a binder is blended with the nanosheet layer forming coating solution, the dispersion medium is preferably a solvent that dissolves the binder. The dispersion medium may be a single liquid or a mixed liquid obtained by mixing two or more liquids.
As the dispersion medium, water is preferably used. You may use water and an organic solvent together as needed. As the dispersion medium, an organic solvent may be used alone.
Examples of the organic solvent include alcohols (methanol, ethanol, isopropanol, butanol, diacetone alcohol, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ethers (tetrahydrofuran, 1,4-dioxane, etc.), Cellosolves (methyl cellosolve, ethyl cellosolve, etc.), esters (methyl acetate, ethyl acetate, etc.), glycol ethers (ethylene glycol monoalkyl ether, etc.), nitrogen-containing compounds (N, N-dimethylacetamide, N, N-dimethyl) Formamide, N-methylpyrrolidone, etc.), sulfur-containing compounds (dimethyl sulfoxide, etc.) and the like. Among these, alcohols are preferable and methanol and ethanol are particularly preferable in terms of solvent drying property, water compatibility, and surface tension.

Binder or its precursor:
When a layer containing a binder is formed as the nanosheet layer 26, a binder or a precursor thereof is blended in the nanosheet layer forming coating solution. For example, when the binder is a condensate of a hydrolyzate of a hydrolyzable silane compound, a binder precursor is blended in the nanosheet layer forming coating solution. The binder precursor may be a hydrolyzate of a hydrolyzable silane compound or a hydrolyzable silane compound that is a precursor thereof.
The description of the binder and its precursor is the same as described above.

When the coating liquid for forming the nanosheet layer contains a binder, the content is such that the mass ratio of the content of the nanosheet to the total amount of the nanosheet and the binder or its precursor (nanosheet / (nanosheet + binder)) is 0. The amount is preferably 25 or more. The value of nanosheet / (nanosheet + binder) is more preferably 0.375 or more, and particularly preferably 0.50 or more. When the nanosheet / (nanosheet + binder) is 0.25 or more, the decrease in the antireflection performance of the silica-based porous layer 21 due to the penetration of the binder is suppressed, and the maximum transmittance is decreased by providing the nanosheet layer 26. Can be sufficiently suppressed. 80-100 mass% is preferable with respect to the total mass of the solid content in the coating liquid for nanosheet layer formation, and, as for the total amount of a nanosheet and a binder or its precursor, 90-100 mass% is more preferable.
When the binder is a hydrolyzate of a hydrolyzable silane compound, the content of the binder or its precursor is in terms of SiO ₂ solids.

  When a binder or a precursor thereof is included, the nanosheet layer forming coating solution is prepared, for example, by mixing a nanosheet dispersion and a binder or a precursor solution thereof.

Other ingredients:
You may mix | blend other components other than a nanosheet, a binder, and its precursor with the coating liquid for nanosheet layer formation as needed.
As the other component, a surfactant is preferable.
The compounding amount of the surfactant is preferably such that the mass ratio of the surfactant content to the nanosheet content (surfactant / nanosheet) is 1.5 or less. When the surfactant / nanosheet exceeds 1.5, the transmittance tends to decrease due to the penetration of the surfactant component into the porous silica membrane.

  The solid content concentration in the coating liquid for forming the nanosheet layer is preferably 0.05 to 0.20% by mass, and more preferably 0.05 to 0.15% by mass. If the solid content concentration in the coating liquid for forming the nanosheet layer is equal to or higher than the lower limit, the antifouling property is improved. On the other hand, if it is not more than the above upper limit value, it is possible to prevent a decrease in average transmittance due to the nanosheet layer 26 becoming thicker.

Application method:
As a coating method of the coating liquid for forming the nanosheet layer, known wet coating methods (spin coating method, spray coating method, dip coating method, die coating method, curtain coating method, screen coating method, ink jet method, flow coating method, gravure coating) Method, bar coat method, flexo coat method, slit coat method, roll coat method, sponge roll coat method, squeegee coat method, etc.).
The coating temperature (base material) is preferably room temperature to 80 ° C, more preferably 35 to 60 ° C.

Dry:
After the application, the nanosheet layer 26 is formed by drying or the like.
When the coating liquid for forming the nanosheet layer contains only the nanosheet as a solid content, that is, when it contains no optional components other than the nanosheet (binder or its precursor, surfactant, etc.), the drying after coating is performed using a dispersion medium. The drying condition is not particularly limited as long as it can be removed, but it is preferable that the following drying condition 1 is satisfied.
Drying condition 1: It is performed at a drying temperature of 300 ° C. or lower (more preferably 250 ° C. or lower, more preferably 200 ° C. or lower). If it is below the upper limit, it is possible to prevent the nanosheet and the silica-based porous layer and between the nanosheets from being strongly sintered, and the removability of the nanosheet layer 26 during outdoor exposure is not sacrificed.
Although the minimum in particular of a drying temperature is not restrict | limited, What is necessary is just room temperature or more with a substrate temperature, 60 degreeC or more is preferable and 80 degreeC is more preferable. If it is more than the said lower limit, a dispersion medium will fully be removed in a short time.

When the coating solution for forming the nanosheet layer contains a binder or a precursor thereof, it is preferable to perform drying after coating at a temperature that satisfies the above-described drying condition 1 and does not exceed the thermal decomposition temperature of the binder. When heated to a temperature equal to or higher than the thermal decomposition temperature, the binder in the nanosheet layer 26 is thermally decomposed, and the effect of including the binder (for example, improved adhesion between nanosheets in the nanosheet layer 26, improved denseness of the nanosheet layer 26, etc.) ) May be damaged.
Although the minimum in particular of a drying temperature is not restrict | limited, What is necessary is just room temperature or more with a substrate temperature, 60 degreeC or more is preferable and 80 degreeC is more preferable. If it is more than the said lower limit, a dispersion medium will fully be removed.

When the coating liquid for forming the nanosheet layer contains an organic substance other than the binder and its precursor, such as a surfactant, the drying after the application satisfies the above-mentioned drying condition 1 and exceeds the thermal decomposition temperature of the organic substance. It is preferable to carry out the drying at a temperature that does not occur. When heated to a temperature equal to or higher than the thermal decomposition temperature, the organic substance may be thermally decomposed and the effects of inclusion may be impaired.
Although the minimum in particular of a drying temperature is not restrict | limited, What is necessary is just room temperature or more with a substrate temperature, 60 degreeC or more is preferable and 80 degreeC is more preferable. If it is more than the said lower limit, a dispersion medium will fully be removed.
The thermal decomposition temperature of the organic substance can be measured by differential thermal-thermogravimetric simultaneous measurement (TG-DTA).

<Second embodiment of the present invention>
The article of the present invention may include a functional layer 30 between the transparent substrate and the antifouling antireflection film.
A schematic cross-sectional view of a second embodiment in which the article of the present invention has a functional layer 30 is shown in FIG.
The article 2 is the same as the article 1 except that the functional layer 30 is provided between the transparent substrate 10 and the antifouling antireflection film 20.
In the present embodiment, the same reference numerals are given to the components corresponding to the first embodiment, and detailed description thereof will be omitted.

(Functional layer 30)
As the functional layer 30, an undercoat layer, an adhesion improving layer, a protective layer, a fingerprint removing layer, an antistatic layer, a water-repellent nanosheet layer, a hydrophilic nanosheet layer, an ultraviolet shielding layer, an infrared shielding layer, a wavelength conversion layer, an antiglare layer Etc.
For example, the undercoat layer functions as an alkali barrier layer or a wide band low refractive index layer. By having the undercoat layer between the transparent substrate 10 and the silica-based porous layer 21, durability, in particular, heat and moisture resistance is further improved. Further, since the antireflection performance and the reflected color are achromatic, the appearance and the like are improved.

As an undercoat layer, a layer composed only of a matrix mainly composed of silica, a layer having a plurality of pores in a matrix mainly composed of silica, a solid silica particle in a matrix mainly composed of silica And a layer having silica hollow particles in a matrix mainly composed of silica.
Examples of the matrix mainly composed of silica include a heat-treated product of sol-gel silica (hydrolyzed product or partial condensate of alkoxysilane), a heat-treated product of silazane, and the like, and a heat-treated product of sol-gel silica is preferable.
60-200 nm is preferable and, as for the layer thickness of an undercoat layer, 80-150 nm is more preferable.
The refractive index of the undercoat layer is preferably 1.30 to 1.46, more preferably 1.35 to 1.42.
The measurement methods of the thickness and refractive index of the undercoat layer are the same as the measurement methods of “average layer thickness” and “refractive index” shown in Examples described later, respectively.

As the alkoxysilane used for the sol-gel silica, the compound (a1), the compound (a2), and other known alkoxysilanes can be used. For example, tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetra Butoxysilane, etc.), alkoxysilanes having perfluoropolyether groups (perfluoropolyethertriethoxysilane, etc.), alkoxysilanes having perfluoroalkyl groups (perfluoroethyltriethoxysilane, etc.), alkoxysilanes having vinyl groups ( Vinyltrimethoxysilane, vinyltriethoxysilane, etc.), alkoxysilane having an epoxy group (2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyl) Trimethoxysilane, 3-glycidoxypropyl methyl diethoxy silane, 3-glycidoxypropyl triethoxysilane, etc.), acryloyl alkoxysilane having an oxy group (3-acryloyloxy propyl trimethoxysilane and the like) and the like.
The hydrolyzate and partial condensate of alkoxysilane can be obtained in the same manner as the hydrolyzate and partial condensate of compound (a1).

(Manufacturing method of article 2)
The article 2 can be manufactured, for example, by sequentially forming the functional layer 30, the silica-based porous layer 21, and the nanosheet layer 26 on the transparent substrate 10.
Hereinafter, the detail of the manufacturing method of the articles | goods 2 in case the functional layer 30 is an undercoat layer is demonstrated.

{Undercoat layer forming step}
In the undercoat layer forming step, a coating liquid for forming an undercoat layer (hereinafter referred to as “undercoat layer forming coating liquid”) is applied to the surface of the transparent substrate 10 and dried by heat treatment or the like. An undercoat layer is formed. Thereby, the transparent base material 30 is obtained.

Undercoat layer forming coating solution:
The coating liquid for forming the undercoat layer includes a matrix precursor solution (sol-gel silica solution, silazane solution, etc.); a mixture of particles (B) or a dispersion of hollow particles and a matrix precursor solution; Examples thereof include a mixture of a particle dispersion and a matrix precursor solution.
The coating solution for forming the undercoat layer may contain a surfactant for improving leveling properties, a metal compound for improving durability of the coating film, and the like.

Examples of the matrix precursor include sol-gel silica (alkoxysilane hydrolyzate or partial condensate), silazane and the like, and sol-gel silica is preferable.
As the alkoxysilane, the compound (a1), the compound (a2), and other known alkoxysilanes can be used. For example, tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc.), Alkoxysilane having a perfluoropolyether group (such as perfluoropolyethertriethoxysilane), alkoxysilane having a perfluoroalkyl group (such as perfluoroethyltriethoxysilane), alkoxysilane having a vinyl group (vinyltrimethoxysilane, Vinyltriethoxysilane, etc.), alkoxysilanes having an epoxy group (2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-g Sid propyl methyl diethoxy silane, 3-glycidoxypropyl triethoxysilane, etc.), acryloyl alkoxysilane having an oxy group (3-acryloyloxy propyl trimethoxysilane and the like) and the like.
Sol-gel silica can be obtained by the same method as the hydrolyzate and partial condensate of compound (a1).

Examples of the solvent for the matrix precursor include those similar to the liquid medium (C), and a mixed solvent of water and alcohols (methanol, ethanol, isopropanol, butanol, diacetone alcohol, etc.) is preferable.
As a dispersion medium for the dispersion liquid of particles (B), hollow particles, or silica solid particles, water, alcohols, ketones, ethers, cellosolves, esters, glycol ethers, nitrogen-containing compounds, sulfur-containing compounds, etc. And the same as those mentioned for the liquid medium (C).

Application method:
As a coating method of the coating liquid for forming the undercoat layer, known wet coating methods (spin coating method, spray coating method, dip coating method, die coating method, curtain coating method, screen coating method, ink jet method, flow coating method, gravure) Coating method, bar coating method, flexo coating method, slit coating method, roll coating method, etc.).
The coating temperature (base material) of the coating liquid for forming the undercoat layer is preferably room temperature to 200 ° C, more preferably room temperature to 150 ° C.

Heat treatment:
The heat treatment may be performed only after the silica-based porous layer forming coating solution is applied, or may be performed after each application of the undercoat layer-forming coating solution and the silica-based porous layer forming coating solution. Alternatively, the transparent substrate 10 may be heated to a heat treatment temperature in advance, and an undercoat layer forming coating solution and a silica-based porous layer forming coating solution may be sequentially applied to the surface of the transparent substrate 10.
50-300 degreeC is preferable and the heat processing temperature in the case of performing heat processing after apply | coating the coating liquid for undercoat layer formation, before apply | coating the coating liquid for silica type porous layer formation is more preferable.

{First step and second step}
After forming the undercoat layer, the silica-based porous layer 21 and the nanosheet layer 26 are sequentially formed. Note that the step of forming the silica-based porous layer 21 and the step of forming the nanosheet layer 26 may be performed in the same manner as the first step and the second step of the above-mentioned “Production Method 1”, respectively.

<Other Embodiments of the Present Invention>
Although the present invention has been described with reference to the first and second embodiments, the present invention is not limited to these embodiments. Each configuration in these embodiments, a combination thereof, and the like are exemplifications, and the addition, omission, replacement, and other changes of the configuration can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the silica-based porous layer forming coating solution is applied on the transparent substrate 10, heat-treated, and the series of steps of removing the particles (B) is performed once to perform the silica-based porous layer. Although an example in which the layer 21 is formed is shown, the present invention is not limited to this. For example, the silica-based porous layer 21 may be a film formed by performing the above process a plurality of times. From the viewpoint of ease of production, film homogeneity, etc., it is preferably a film formed by performing the above process once or twice, and a film formed by performing the above process once. It is particularly preferred that
When performing the said process twice or more, the composition (a kind, a compounding quantity, etc. of a matrix precursor (A) and particle | grains (B)) of the coating liquid used at each process may be the same, or may differ.

<Operational effects of the present invention>
In the present invention, the antireflection performance of the porous layer in the silica-based porous layer is provided by including the transparent substrate and the antifouling antireflection film having the above-described predetermined silica-based porous layer and nanosheet layer. It is possible to provide an article and a manufacturing method with high antifouling properties on the surface while maintaining the same.

  While the present invention has been described with reference to the exemplary embodiments, the present invention is not limited to the above-described embodiments. Each configuration in the above embodiment, a combination thereof, and the like are examples, and the addition, omission, replacement, and other modifications of the configuration can be made without departing from the spirit of the present invention.

<Evaluation method>
(Average transmittance)
The transmittance of light incident at an incident angle of 0 ° on the surface of the antifouling antireflection film side of an article comprising the produced transparent substrate and the antifouling antireflection film is measured with a spectrophotometer (manufactured by Hitachi, Ltd., model: U-4100) and the average transmittance (%) in the wavelength range of 400 to 1100 nm was determined. In addition, in order to prevent the back surface light diffusion of the glass plate, the measurement was performed by attaching quartz glass to the back surface with anisole.

(Average layer thickness)
The average layer thickness of the undercoat layer, the average layer thickness d2 of the porous layer, and the average layer thickness d1 of the antifouling layer are obtained by scanning the cross section of an article comprising the manufactured transparent substrate and the antifouling antireflection film with a scanning electron microscope SEM It was measured from an image obtained by observation with (manufactured by Hitachi, Ltd., model: S-4300). The average layer thickness was obtained by measuring 100 points for each layer and calculating the average value thereof.

(Refractive index)
The refractive index of the undercoat layer, the silica-based porous layer, and the nanosheet layer was measured with an ellipsometer (manufactured by JA Woollam, model: M-2000DI) on a sample in which each layer or film was formed on a transparent substrate. The refractive index at a wavelength of 589.3 nm was obtained. In addition, in order to prevent the back surface light reflection of a transparent base material, the back surface was painted black and measured.

(Average opening diameter)
The average opening diameter in the silica-based porous layer of the article comprising the manufactured transparent substrate and the antifouling antireflection film was measured using a scanning electron microscope SEM (manufactured by Hitachi, Ltd., model: S-4300), using the SEM. In the longitudinal section of the antifouling antireflection film obtained in the above, the opening diameters of 100 randomly selected holes were measured, and the average value (nm) thereof was calculated and obtained.
However, when calculating the average opening diameter, holes having an opening diameter of 3 nm or less were excluded from the object.

(Water contact angle)
From the injection needle, 1 μL of water droplets (20 ± 5 ° C.) are dropped onto the outermost surface of the antifouling antireflection film at 6 intervals at 1.5 cm intervals, and θ / 2 from the radius and height of the water droplets taken from the horizontal direction. Each contact angle was calculated by the method, and the average value of 6 points was defined as the contact angle (°) of the film.

(Number of holes on the outermost surface)
The number of holes on the outermost surface (pieces / 10 ⁶ nm ² ) is within the region of 900 nm × 900 nm from the image of the outermost surface of the article obtained by a scanning electron microscope SEM (manufactured by Hitachi, Ltd., model: S-4300) The number of pores having an opening diameter of 20 nm or more present in was counted, and this was calculated by converting per 10 ⁶ nm ² .

(Resin peel strength test)
A 0.8 mm thick ethylene-vinyl acetate copolymer resin film (hereinafter referred to as “EVA film”) is cut into a width of 5 mm and a length of 80 mm and placed on the surface of the article obtained in each example on the nanosheet layer side. The EVA film was attached to the article by holding in a drying oven at 160 ° C. for 30 minutes. The article to which the EVA film is adhered is removed from the drying furnace, and after the temperature of the transparent substrate is lowered to room temperature, the force necessary to peel off the EVA film adhered to the nanosheet layer using a spring balance (hereinafter referred to as “peeling force”). The unit: g / 5 mm) was measured.
It shows that an EVA film is easy to peel, that is, it is excellent in antifouling property, so that peeling force is small. Specifically, when the peeling force is 700 g / 5 mm or less, it can be said that the antifouling property is excellent, and when it is 500 g / 5 mm or less, it can be said that it is more remarkably excellent.

(Brightness difference before and after resin adhesion)
Except for changing the width of the EVA film to 25 mm, the EVA film was attached to the article and peeled in the same procedure as the resin peel strength test.
Using a color difference meter (“CR-200” manufactured by Konica Minolta Co., Ltd.), the lightness difference (ΔY) before and after the EVA film was adhered (hereinafter simply referred to as “lightness difference (ΔY)”) was measured. When the brightness difference (ΔY) is 0.6 or less, it can be said that the antifouling property is excellent, and when it is 0.3 or less, the antifouling property is remarkably excellent.

<Example 1>
(Adjustment of coating solution for undercoat layer formation)
Hollow silica particles (“Suriria 4110” manufactured by JGC Catalysts & Chemicals, average primary particle size: 60 nm) are dispersed in water so that the solid content concentration in terms of SiO ₂ is 20% by mass. Liquid A).
Tetraethoxysilane (manufactured by Kanto Chemical Co., Inc.) was dissolved in a 90% by mass ethanol aqueous solution as a matrix raw material so that the solid content concentration in terms of SiO ₂ was 3% by mass, and this was used as a matrix solution (D solution).
By mixing A liquid, D liquid, and isopropanol in the amounts shown in Table 1, a coating liquid for forming an undercoat layer having a solid content concentration in terms of SiO ₂ of 2.0% by mass was prepared.
In this example, the solid content concentration in terms of SiO _{2 is the} solid content concentration when all the Si of the silane compound is converted to SiO ₂ when the solid content contains a silane compound, and other solid content Means the sum of the concentrations of

(Preparation of silica-based porous layer forming coating solution)
Polymethylmethacrylate (“Epester MX050W” manufactured by Nippon Shokubai Co., Ltd., average primary particle size: 50 nm) is dispersed in water so that the solid content concentration is 15% by mass, and this is dispersed into an organic polymer nanoparticle dispersion liquid (liquid B). ).
Silica (Nissan Chemical “Snowtex OUP”, primary particle size: 15 to 100 nm) is dispersed in water so that the solid concentration is 15% by mass, and this is dispersed into a chain silica nanoparticle dispersion (liquid C). It was.
Tetraethoxysilane (manufactured by Kanto Chemical Co., Inc.) (as compound (A1)) (97% by mass) and polydimethylsiloxane (Shin-Etsu Chemical Co., Ltd.) in a 90% by mass ethanol aqueous solution so that the SiO ₂ equivalent solid content concentration is 3% by mass. (Made by Kogyo Co., Ltd.) (as compound (A2)) (3% by mass) was dissolved to obtain a matrix solution (E solution). In addition, the ratio of content of the compound (A1) and the compound (A2) in the liquid E is 19 when converted to a molar ratio of “(a1) / (a2)”.
Liquid B or liquid C, liquid E and isopropanol were mixed in the amounts shown in Table 1 to prepare a coating solution for forming a silica-based porous layer having a solid content concentration of 2.0% by mass.

(Adjustment of coating solution for nanosheet layer formation)
Synthetic smectite having a refractive index of 1.58, an average thickness of 4.1 nm, an average width of 134 nm, and an average area of 9471 nm ² (“Lucentite SWN” manufactured by Coop Chemical Co., Ltd.) was dispersed in water, and this was designated as liquid F.
The coating liquid for nanosheet layer formation whose solid content concentration was 0.05 mass% was prepared by mixing F liquid and water by the mass shown in Table 1.

(Transparent substrate)
Template glass (Solite, low iron soda lime glass (white plate glass), size: 400 mm × 400 mm, thickness: 3.2 mm) was used as a transparent substrate.
The surface of the template glass was polished with an aqueous cerium oxide dispersion, and the cerium oxide was washed away with water, rinsed with ion-exchanged water, and dried.

(Undercoat layer forming process)
The undercoat layer forming coating solution was applied to the transparent substrate by roll coating.
Roll coating was performed under the conditions of a roll rotation speed of 13 m and a conveyance speed of 8.5 m.
Next, the template glass coated with the undercoat layer forming coating solution was heat-treated at 80 ° C. for 1 minute.

(First step)
Next, the template glass was preheated in a preheating furnace (manufactured by ISUZU, VTR-115), and a reverse roll coater (manufactured by Sanwa Seiki Co., Ltd.) was formed on the undercoat layer in a state where the glass surface temperature was kept at 30 ° C. The coating liquid for forming a silica-based porous layer was applied using a coating roll.
The coating conditions were a substrate conveyance speed of 8.5 m / min, a gap between the coating roll and the conveyor belt: 2.9 mm, and an indentation thickness between the coating roll and the doctor roll: 0.6 mm.
As the coating roll, a rubber lining roll lined with rubber (ethylene propylene diene rubber) having a surface hardness (JIS-A) of 30 was used.
As the doctor roll, a metal roll having lattice-like grooves formed on the surface thereof was used.
Next, heat treatment was performed at 650 ° C. for 5 minutes in the atmosphere.

(Second step)
The transparent base material on which the undercoat layer and the silica-based porous layer are formed is kept warm so that the glass surface temperature is 45 ° C. The nanosheet layer forming coating solution was applied.
Next, an article having an antifouling antireflection film formed on a transparent substrate was obtained by drying at room temperature.

<Examples 2 to 4>
About Examples 2-4, except having made the mass of the F liquid and water which were used for adjustment of the coating liquid for nanosheet layer formation shown in Table 1, it carried out prevention on a transparent substrate like Example 1. An article on which a dirty antireflection film was formed was obtained.

<Comparative Example 1>
For Comparative Example 1, an article in which an antifouling antireflection film was formed on a transparent substrate was obtained in the same manner as in Example 1 except that the nanosheet layer was not formed by not performing the second step. It was.

<Comparative Example 2>
For Comparative Example 2, the B liquid used for adjusting the coating liquid for forming the silica-based porous layer is replaced with the C liquid, and used for adjusting the C liquid, E liquid, mass of isopropanol, and nanosheet layer forming coating liquid. An article in which an antifouling antireflection film was formed on a transparent substrate was obtained in the same manner as in Example 1 except that the masses of the prepared F liquid and water were as shown in Table 1.
The evaluation results of Examples 1 to 4 and Comparative Examples 1 and 2 are shown in Table 2.
In addition, since the void | hole of the silica type porous layer became a continuous hole about the article manufactured by the comparative example 2, the opening diameter of a void | hole could not be measured but an average opening diameter was not able to be calculated.

  As shown in Table 2, the articles produced in Examples 1 to 4 having a nanosheet layer have fewer outermost surface openings than Comparative Example 1 that does not have a nanosheet layer, and EVA peel strength and brightness difference. (ΔY) was low. This means that Examples 1 to 4 have a nanosheet layer and thus have excellent antifouling properties.

However, since the article manufactured in Example 4 increased the mass of the nanosheet included in the used coating liquid for forming the nanosheet layer, the average layer thickness of the antifouling layer was 12.0 nm, and as a result, the average transmittance was compared. Compared to Example 1, it was slightly lower.
On the other hand, if the average antifouling layer thickness (about 1.0 nm, 2.0 nm, and 7.0 nm, respectively) of the articles of Examples 1 to 3 is set, the average transmittance by providing the nanosheet layer on the dense layer. There was no decrease in This means that good power generation efficiency is maintained when the articles of Examples 1 to 3 are used as a solar cell cover member.

Since the article manufactured in Comparative Example 2 increased the mass of the nanosheet included in the used coating liquid for forming the nanosheet layer in the same manner as the article in Example 4, the average layer thickness of the antifouling layer was higher than those in Examples 1 to 3. Also thickened. Therefore, the average transmittance of the article of Comparative Example 2 was slightly lower than that of Comparative Example 1.
In Comparative Example 2, chain silica nanoparticles were used in place of the organic polymer nanoparticles as particles to be included in the silica-based porous layer forming coating solution. As a result, the holes became continuous holes and the number of holes on the outermost surface increased. Therefore, the EVA peeling force and brightness difference (ΔY) of the article of Comparative Example 2 were higher than those of Examples 1 to 4. This means that the articles of Examples 1 to 4 have excellent antifouling properties because the pores in the silica-based porous layer are independent pores and the number of outermost surface openings is small. To do.

  Articles of the present invention include vehicle transparent parts (headlight covers, side mirrors, front transparent substrates, side transparent substrates, rear transparent substrates, etc.), vehicle transparent parts (instrument panel surfaces, etc.), meters, architectural windows, Show windows, displays (notebook computers, monitors, LCDs, PDPs, ELDs, CRTs, PDAs, etc.), LCD color filters, touch panel substrates, pickup lenses, optical lenses, eyeglass lenses, camera components, video components, CCD cover substrates , Optical fiber end face, projector parts, copying machine parts, transparent substrate for solar cell, mobile phone window, backlight unit parts (for example, light guide plate, cold cathode tube, etc.), backlight unit parts, liquid crystal brightness enhancement film (for example, prism, Transflective film, etc.), LCD brightness enhancement film , Organic EL light-emitting element parts, inorganic EL light-emitting element parts, phosphor light-emitting element parts, optical filters, end faces of optical parts, illumination lamps, covers for lighting fixtures, amplified laser light sources, antireflection films, polarizing films, agricultural films, etc. Useful as.

DESCRIPTION OF SYMBOLS 1, 2 Goods 10 Transparent base material 20 Antifouling anti-reflective film 21 Silica type porous layer 22 Porous layer 23 Matrix 24 Pore 25 Dense layer 26 Nano sheet layer 30 Functional layer

Claims (10)

A transparent base material, and an antifouling antireflection film provided on the transparent base material,
The antifouling antireflection film has a silica-based porous layer and a nanosheet layer in order from the transparent substrate side,
The silica-based porous layer has a refractive index in the range of 1.10 to 1.38,
The nanosheet layer has a plurality of nanosheets having a refractive index of 1.30 to 1.80,
The water contact angle on the surface of the antifouling antireflection film is less than 60 °,
The number of holes having an opening diameter of 20 nm or more opened on the surface of the antifouling antireflection film is 8/10 ⁶ nm ² or less.   The article according to claim 1, wherein the silica-based porous layer includes a dense layer on the nanosheet layer side, and an average layer thickness d1 obtained by combining the dense layer and the nanosheet layer is 1 to 10 nm.   The article according to claim 2, wherein the silica-based porous layer comprises a porous layer on the transparent substrate side, and the average layer thickness d2 of the porous layer is 60 to 200 nm.   The article according to claim 2 or 3, wherein a ratio (d1 / d2) of the average layer thickness d1 to the average layer thickness d2 of the porous layer is 0.005 to 0.17.   The article according to any one of claims 1 to 4, wherein the nanosheet is derived from an inorganic layered compound selected from layered polysilicates and clay minerals.   The article according to any one of claims 1 to 5, further comprising an undercoat layer between the transparent substrate and the antifouling antireflection film.   The article according to any one of claims 1 to 6, wherein an average opening diameter of pores in a longitudinal section of the silica-based porous layer is 15 to 100 nm. A method for producing an article, comprising: a transparent base material; and an antifouling antireflection film provided on the transparent base material,
A step of applying a coating liquid for forming a silica-based porous layer containing a matrix precursor (A), particles (B), and a liquid medium (C) onto a transparent substrate, and a matrix precursor ( Forming a silica-based porous layer, comprising: forming a matrix from A); and removing the particles (B) before or after or during the heat treatment after the coating;
Applying a nanosheet layer forming coating solution on the surface of the silica-based porous layer and drying to form a nanosheet layer;
The matrix precursor (A) comprises at least one compound (A1) selected from a compound (a1) represented by the following general formula (a1), a hydrolyzate and a partial condensate thereof, and the following general formula (a2) And at least one compound (A2) selected from the hydrolyzate and partial condensate thereof, and the compound (A1) in the matrix precursor (A) And the ratio of the content of the compound (A2) is in the range of 5 to 60 in terms of the molar ratio ((a1) / (a2)) between the compound (a1) and the compound (a2). The average primary particle diameter of the particles (B) is 20 to 130 nm,
The nanosheet layer forming coating solution contains a plurality of nanosheets and a dispersion medium of the nanosheet, and the nanosheet has a refractive index of 1.30 to 1.80.
SiX ₄ (a1)
Y _n SiX _4-n (a2)
[Wherein, X represents a hydrolyzable group, Y represents a non-hydrolyzable group having a dielectric constant of Y-OH of 35 F / m or less, and n represents an integer of 1 to 3. ]   The step of forming the silica-based porous layer comprises applying a coating solution for forming a silica-based porous layer containing a matrix precursor (A), particles (B1) that can be removed by heat treatment, and a liquid medium (C). The method for producing an article according to claim 8, comprising a step of coating on a transparent substrate, and a step of forming a matrix from the matrix precursor (A) by heat treatment and removing the particles (B1).   The method for producing an article according to claim 8 or 9, wherein the drying temperature in the step of forming the nanosheet layer is 300 ° C or lower.

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