JP2014079920A - Article and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an article in which while antireflection performance of a porous siliceous film is maintained, an antifouling property is raised, favorable appearance can be maintained for a long period, and a production method of the same.SOLUTION: There is provided an article that includes a multilayer film that comprises a porous siliceous film, and an outermost surface layer that is disposed in contact with the porous siliceous film on a transparent substrate. The article is characterized in that a refraction index at 550 nm of a wave length of the multilayer film is at most 1.428, a beginning water contact angle of the outermost surface layer is at least 80°, and a water contact angle after light of 300-800 nm of a wave length is exposed by 650 W/mof irradiance for 1,000 hours is at most 76°.

Description

  The present invention relates to an article having a multilayer film composed of a silica-based porous film and an outermost layer provided in contact with the silica-based porous film on a transparent substrate, 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 (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 many fine open holes and irregularities on the surface, there is a problem that dirt easily adheres and the attached dirt is difficult to remove.
For example, in the manufacturing process of the solar cell, a step of bonding the cover member and the solar 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. In addition, the soaked EVA is difficult to peel off from the silica-based porous film, and even after peeling, the color of the silica-based porous film where the EVA has soaked becomes different from the other parts. There are also problems such as.

As a countermeasure against the problems in the above manufacturing process and the like, a protective film is provided on a silica-based porous film. However, the method of providing the protective film increases the cost.
A method of applying a fluorine-based coating agent to the surface of a silica-based porous film has also been proposed (for example, Patent Document 2).
The method of applying a fluorine-based coating agent can improve the antifouling property against oil stains and EVA easily and at a lower cost than when a protective film is provided. 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. In addition, the silica-based porous film coated with a fluorine-based coating agent, after being installed outdoors as a solar cell module, due to the effect of super water repellency, dirt is likely to remain scattered and not flow down uniformly due to rainwater, etc. There are problems such as the fact that water marks are easily attached due to rainwater and the like, and it is difficult to maintain a good appearance over a long period of time.

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

  The present invention has been made in view of the above circumstances, and provides an article capable of maintaining a good appearance over a long period of time while maintaining the antireflection performance of the silica-based porous film and improving the antifouling property, and a method for producing the same. For the purpose.

The present invention has the following aspects.
[1] An article having a multilayer film comprising a silica-based porous film and an outermost layer provided in contact with the silica-based porous film on a transparent substrate,
The multilayer film has a refractive index of 1.428 or less at a wavelength of 550 nm,
The initial water contact angle of the outermost layer is 80 ° or more, and the water contact angle after exposing light having a wavelength of 300 to 800 nm at an irradiance of 650 W / m ² for 1000 hours is 76 ° or less. Goods to be.
[2] The article according to [1], wherein the number of open pores having a diameter of 20 nm or more opened on the surface on the outermost layer side of the silica-based porous membrane is 16 or less per 1000 nm × 1000 nm.
[3] The outermost layer is composed of a silicone polymer,
The silicone polymer is a copolymer of a compound (X) represented by the following general formula (x) and a compound (Y) represented by the following general formula (y),
The molar ratio (Y / (X + Y)) of the compound (Y) to the total amount of the compound (X) and the compound (Y) is 0.2 to 0.8,
The article according to [1] or [2], wherein the silicone polymer has a weight average molecular weight of 750 to 5,000.
Si (OR ¹ ) ₄ (x)
R ³ Si (OR ² ) ₃ (y)
[Wherein R ¹ is an alkyl group having 1 to 3 carbon atoms, and a plurality of R ¹ in the formula may be the same or different, and R ² is an alkyl group having 1 to 3 carbon atoms. And a plurality of R ² in the formula may be the same or different, and R ³ is a hydrocarbon group having 1 to 20 carbon atoms. ]
[4] The article according to any one of [1] to [3], wherein the thickness of the outermost layer is 3 to 20 nm.

[5] An article having a multilayer film composed of a silica-based porous film and an outermost layer provided in contact with the silica-based porous film on a transparent substrate,
The number of open pores having a diameter of 20 nm or more opened on the surface on the outermost layer side of the silica-based porous membrane is 16 or less per 1000 nm × 1000 nm,
The outermost layer is composed of a silicone polymer;
The silicone polymer is a copolymer containing a compound (X) represented by the following general formula (x) and a compound (Y) represented by the following general formula (y),
The molar ratio (Y / (X + Y)) of the compound (Y) to the total amount of the compound (X) and the compound (Y) is 0.2 to 0.8,
The weight average molecular weight of the silicone polymer is 750 to 5000,
An article having a thickness of the outermost layer of 3 to 20 nm.
Si (OR ¹ ) ₄ (x)
R ³ Si (OR ² ) ₃ (y)
[Wherein R ¹ is an alkyl group having 1 to 3 carbon atoms, and a plurality of R ¹ in the formula may be the same or different, and R ² is an alkyl group having 1 to 3 carbon atoms. And a plurality of R ² in the formula may be the same or different, and R ³ is a hydrocarbon group having 1 to 20 carbon atoms. ]
[6] The article according to claim 5, wherein the multilayer film has a refractive index of 1.428 or less at a wavelength of 550 nm.

[7] A method for producing an article having a multilayer film composed of a silica-based porous film and an outermost layer provided in contact with the silica-based porous film on a transparent substrate,
A step of applying an overcoat liquid to the surface of the silica-based porous film of the transparent substrate with a silica-based porous film having a silica-based porous film on the transparent substrate, and drying to form an outermost layer. Including
The overcoat liquid contains a silicone polymer and a solvent,
The silicone polymer is a copolymer of a compound (X) represented by the following general formula (x) and a compound (Y) represented by the following general formula (y),
The molar ratio (Y / (X + Y)) of the compound (Y) to the total amount of the compound (X) and the compound (Y) is 0.2 to 0.8,
The manufacturing method of the articles | goods whose weight average molecular weights of the said silicone polymer are 750-5000.
Si (OR ¹ ) ₄ (x)
R ³ Si (OR ² ) ₃ (y)
[Wherein R ¹ is an alkyl group having 1 to 3 carbon atoms, and a plurality of R ¹ in the formula may be the same or different, and R ² is an alkyl group having 1 to 3 carbon atoms. And a plurality of R ² in the formula may be the same or different, and R ³ is a hydrocarbon group having 1 to 20 carbon atoms. ]
[8] The method for producing an article according to [7], wherein the number of open pores having a diameter of 20 nm or more opened on the surface on the outermost layer side of the silica-based porous membrane is 16 or less per 1000 nm × 1000 nm. .
[9] The method for producing an article according to [7] or [8], wherein the thickness of the outermost layer is 3 to 20 nm.
[10] The method for producing an article according to any one of [7] to [9], wherein the multilayer film has a refractive index of 1.428 or less at a wavelength of 550 nm.

  ADVANTAGE OF THE INVENTION According to this invention, the article | item which can maintain the favorable external appearance over the long term which improved antifouling property, maintaining the antireflection performance of a silica type porous membrane, and its manufacturing method can be provided.

It is sectional drawing which shows one Embodiment of the articles | goods of this invention. FIG. 2 is a schematic cross-sectional view in a state where the outermost layer is removed from the article (state of a transparent substrate with a silica-based porous film) for schematically explaining the configuration of the silica-based porous film in the article shown in FIG. is there.

Hereinafter, the present invention will be described with reference to exemplary embodiments.
<First embodiment>
FIG. 1 is a cross-sectional view showing a first embodiment of an article of the present invention.
The article 10 of this embodiment includes a transparent substrate 12 and a multilayer film 18 formed on the surface of the transparent substrate 12. The multilayer film 18 includes a silica-based porous film 14 and an outermost layer 16 formed on the surface of the silica-based porous film 14.

[Transparent substrate 12]
Examples of the shape of the transparent substrate 12 include a plate and a film.
Examples of the material of the transparent substrate 12 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 12, 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 0.2 to 10 mm can be used. The thinner the thickness, the lower the light absorption, which is preferable for the purpose of improving the transmittance.

When the glass plate is an architectural or vehicle window glass, soda lime glass having the following composition is preferred.
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 the glass plate is a cover glass for a solar cell, a satin-patterned template glass with an uneven surface is preferable. 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.

A functional layer may be formed on the surface of the transparent substrate 12 in advance.
Examples of the functional layer include an undercoat layer, an adhesion improving layer, a protective layer, and the like. Examples of the undercoat layer include those having a function as an alkali barrier layer or a wide band low refractive index layer. The undercoat layer is preferably a layer formed by applying an undercoat coating composition containing a hydrolyzate of alkoxysilane (sol-gel silica) on a substrate. When applying the coating composition mentioned later on an undercoat layer, the undercoat layer may be baked beforehand and may be in a wet state. When a coating composition is applied on the undercoat layer, the application temperature is preferably room temperature to 80 ° C, and the firing temperature is preferably 30 to 700 ° C. The thickness of the undercoat layer is preferably 10 to 500 nm.

[Multilayer film 18]
The multilayer film 18 is composed of the silica-based porous film 14 and the outermost layer 16 formed on the surface of the silica-based porous film 14, and has a refractive index of 1.428 or less at a wavelength of 550 nm. When the refractive index is 1.428 or less, the multilayer film 18 has sufficient antireflection performance as an antireflection film. The refractive index is preferably 1.20 to 1.428.
The refractive index is obtained by the following procedure.
A silica-based porous film and an outermost layer are sequentially formed on a glass plate to produce a glass plate with a multilayer film, and the film thickness is measured with an electron microscope, etc. calculate.
The refractive index can be adjusted by the refractive index of the silica-based porous film, the material constituting the outermost layer, the film thickness of the outermost layer, and the like. The refractive index of a silica type porous film can be adjusted with the ratio (void rate) of the void | hole occupied in a silica type porous film.

(Silica-based porous film 14)
The “silica-based porous membrane” is a membrane having a plurality of pores in a matrix mainly composed of silica. The silica-based porous film has a relatively low refractive index (reflectance) because the matrix is mainly composed of silica. Moreover, it is excellent in chemical stability, adhesiveness with the transparent base material 12 such as a glass plate, and wear resistance. Furthermore, by having holes in the matrix, the refractive index is lower than when there are no holes.

That the matrix is mainly composed of silica means that the proportion of silica is 90% by mass or more of the matrix (100% by mass).
As a matrix, what consists essentially of silica is preferable. 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 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 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.

The silica-based porous film 14 has a wavelength in a state in which the outermost layer 16 is removed from the article 10, that is, in a state of a transparent substrate with a silica-based porous film having the silica-based porous film 14 on the transparent substrate 12. It is preferable that the maximum transmittance at 400 to 1100 nm (hereinafter, the maximum transmittance is also referred to as “Tmax”) (%) is Tmax (%) at a wavelength of 400 to 1100 nm of transparent substrate 12 + 2.8% or more. .
The value of “Tmax in the state of the transparent substrate with a silica-based porous film” − “Tmax of the transparent substrate 12”, that is, the increase in Tmax due to the provision of the silica-based porous film 14 (hereinafter referred to as “ΔTmax before OC” ") Also indicates that the antireflection performance of the silica-based porous film 14 is higher. When ΔTmax before OC is 2.8% or more, the silica-based porous film 14 has sufficient antireflection performance.

In the silica-based porous film 14, the number of open pores having a diameter of 20 nm or more opened on the surface on the outermost layer 16 side is preferably 16 or less per 1000 nm × 1000 nm.
The larger the size of the pores contained in the matrix of the silica-based porous membrane and the greater the number of pores, the lower the refractive index of the silica-based porous membrane. However, when the conventional silica-based porous membrane includes pores having a diameter of 20 nm or more, a large number of open pores having a diameter of 20 nm or more opened on the surface of the silica-based porous membrane due to the communication of the pores or the like. . Therefore, when an overcoat liquid is applied to the surface to form the outermost layer, the overcoat liquid may permeate into the silica-based porous film from the open pores, and there is a concern that the antireflection performance may be reduced. is there.
The permeation can be suppressed when the number of open holes having a diameter of 20 nm or more per 1000 nm × 1000 nm (hereinafter also referred to as “the number of open holes on the outermost surface”) is 16 or less. In particular, when an overcoat liquid containing a specific silicone polymer, which will be described later, is used, the permeation suppression effect is particularly excellent.
The lower limit of the number of holes on the outermost surface is not particularly limited, and may be 0. Considering the advantage of using the overcoat liquid described later, for example, the advantage that penetration can be suppressed even if there are open holes, the number of outermost open holes is preferably 1 or more, and more preferably 10 or more.
The diameter of the open hole is preferably smaller than 20 nm. If the thickness is smaller than 20 nm, the problem of the penetration is less likely to occur.
The number of open pores on the outermost surface is based on an image obtained by observing the surface of the silica-based porous film 14 (the surface opposite to the transparent substrate 12 side) with a scanning electron microscope (hereinafter also referred to as SEM). The number of openings having a diameter of 20 nm or more existing in the region of 1000 nm × 1000 nm is obtained. When the shape of the opening in the image is not a perfect circle, the average value of the minor axis and the major axis is taken as the diameter.

The silica-based porous film 14 preferably has 16 or less outermost surface open pores, and some or all of the plurality of pores contained in the matrix are pores having a diameter of 20 nm or more.
When there are no holes having a diameter of 20 nm or more, the number of holes on the outermost surface is 16 or less, but the porosity is lowered and the antireflection performance may be insufficient. By having pores having a diameter of 20 nm or more inside the silica-based porous film 14, excellent antireflection performance can be obtained.
The diameter of the pores is measured from an image obtained by observing the cross section of the silica-based porous film 14 using SEM. When the shape of the hole in the image is not a perfect circle, the average value of the minor axis and the major axis is taken as the diameter.

The average diameter of the plurality of pores contained in the matrix of the silica-based porous membrane 14 (hereinafter also referred to as “average pore diameter”) is preferably 15 to 100 nm, and more preferably 20 to 80 nm. When the average pore diameter is 15 nm or more, sufficient antireflection performance as an antireflection film is obtained, and when it is 100 nm or less, the durability and light transmittance of the silica-based porous film 14 are good.
The average pore diameter can be obtained by measuring the diameter of 100 pores from an image obtained by observing the cross section of the silica-based porous film 14 using SEM and calculating the average value thereof.

40-300 nm is preferable and, as for the average total film thickness of the silica type porous membrane 14, 80-200 nm is more preferable. When the average total film thickness of the silica-based porous film 14 is 40 nm or more, light interference occurs in the visible light region, and antireflection performance is exhibited. If the average total film thickness of the silica-based porous film 14 is 300 nm or less, the film can be formed without generating cracks.
The average total film thickness is measured at 100 locations on the silica-based porous film from an image obtained by observing the cross section of the article 10 with a scanning electron microscope SEM (manufactured by Hitachi, Ltd., model: S-4300). Then, an average value thereof is calculated and obtained.

FIG. 2 is a schematic cross-sectional view for schematically explaining the configuration of a silica-based porous film 14 ′ suitable as the silica-based porous film 14. In FIG. 2, for convenience of explanation, a state in which the outermost layer 16 is removed from the article 10, that is, a state of a transparent base material with a silica-based porous film having a silica-based porous film 14 ′ on the surface of the transparent base material 12 is shown. ing.
The silica-based porous film 14 ′ is a film having a two-layer structure composed of a dense layer 14-1 and a non-dense layer 14-2. Both the dense layer 14-1 and the non-dense layer 14-2 have a plurality of pores 22 having a diameter of 20 nm or more in the matrix 21 mainly composed of silica, but the dense layer 14-1 is more non-dense layer. Compared to 14-2, the number of holes 22 in the layer is small.
The diameter of the air holes 22 is preferably 15 nm or more.
The silica-based porous film 14 ′ may have pores with a diameter of less than 20 nm (not shown) in the matrix 21.
The preferable range of the average diameter of pores contained in the matrix 21 (average pore diameter) is the same as described above.
The pores 22 having a diameter of 20 nm or more present in the silica-based porous membrane 14 ′ are preferably independent pores. The term “independent pores” refers to granular pores that exist independently in the matrix. If it is an independent hole, the penetration | invasion to the inside of the silica type porous membrane 14 'of the overcoat liquid mentioned later can further be suppressed. On the other hand, when the plurality of holes 22 are connected, the overcoat tends to penetrate into the film.
Conventionally, as a method of forming a silica-based porous film, a method of applying a coating solution containing silica particles and using voids generated by aggregation of the particles is well known, but in this method, a plurality of pores are connected. It is easy to make a connecting hole. On the other hand, in a silica-based porous film prepared by applying polymer particles together with metal alkoxide and removing the polymer particles by means such as thermal decomposition, pores corresponding to the polymer particles are formed. This hole tends to be an independent hole.

The silica-based porous film 14 ′ has the non-dense layer 14-2, so that the porosity is increased and the refractive index is lowered as compared with the case where only the dense layer 14-1 is formed. Demonstrate prevention performance.
In addition, the silica-based porous film 14 ′ has the dense layer 14-1 on the non-dense layer 14-2, so that the number of open pores on the outermost surface is 16 or less. Thereby, as above-mentioned, permeation when an overcoat liquid is apply | coated can be suppressed. Moreover, durability improves compared with the case where it comprises only the non-dense layer 14-2.
Moreover, durability of silica type porous membrane 14 'improves by having the dense layer 14-1. For example, when a conventional silica-based porous film is directly formed on the surface of a glass plate, the porous structure in the portion in contact with the glass plate under wet heat conditions is broken by the influence of alkali, and the antireflection performance is lowered. In contrast, the silica-based porous film 14 'uses a glass plate as the transparent substrate 12, and maintains a porous structure over a long period of time even when directly formed on the surface of the glass plate and subjected to wet heat conditions. Therefore, the antireflection performance is not easily lowered. The above effect is considered to be due to the fact that the dense layer 14-1 can suppress moisture in the outside air from passing through the silica-based porous membrane 14 ′ and reaching the transparent substrate 12 to generate alkali.
In addition, the influence which the void | hole less than 20 nm in diameter has on durability is small. Therefore, the silica-based porous film 14 ′ may have pores with a diameter of less than 20 nm (not shown) in the dense layer 14-1 and the matrix 21 in other regions.

The silica-based porous film 14 having the configuration shown in FIG. 2 is coated with a coating liquid (coating liquid containing the compound (A1), the compound (A2), the particles (B), and the liquid medium (C)), which will be described later, and subjected to heat treatment. In this case, the dense layer 14-1 and the non-dense layer 14-2 have different compositions of the matrix 21.
As will be described in detail later, when the coating solution is applied to the surface of the transparent substrate 12, the compound (A2) floats in the coating film and phase-separates. Thereby, the compound (A2) phase formed on the outermost surface side of the coating film becomes a dense layer 14-1 by heat treatment. Therefore, the matrix 21 constituting the dense layer 14-1 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 21 constituting the non-dense layer 14-2 is substantially composed of a heat-treated product of the compound (A1), and does not contain or contains very little structure derived from the compound (a2).

The ratio of the average film thickness of the dense layer 14-1 to the average total film thickness (nm) of the silica-based porous film 14 'is not particularly limited, but is preferably 8 to 40%, more preferably 10 to 30%. As the ratio increases, the number of outermost surface open holes tends to decrease. The smaller the ratio, the lower the refractive index and the higher the antireflection performance.
A preferable range of the average total film thickness is the same as described above.
This ratio can be adjusted by the molar ratio ((a1) / (a2)) between the compound (a1) and the compound (a2) in the coating solution described later, the average primary particle diameter of the particles (B), and the like.
For example, when the coating solution is applied and heat-treated, the dense layer 14-1 is mainly formed from the compound (A2). Therefore, if the total amount of the compound (A1) and the compound (A2) is the same, the smaller the (a1) / (a2) (the higher the ratio of the compound (a2)), the higher the average film of the dense layer 14-1 The proportion of thickness tends to increase. Further, as the average primary particle diameter of the particles (B) is larger, only the compound (A2) is likely to float, and the ratio of the average film thickness of the dense layer 14-1 tends to increase.

(Outermost layer 16)
The outermost layer 16 is a layer disposed on the outermost side of the article 10 and is provided in contact with the silica-based porous film 14.
The outermost layer 16 has an initial water contact angle of 80 ° or more and a water contact angle of 76 ° or less after exposing light having a wavelength of 300 to 800 nm at an irradiance of 650 W / m ² for 1000 hours.
The initial water contact angle of the outermost layer 16 indicates the water contact angle immediately after the manufacture of the article 10 (immediately after the formation of the outermost layer 16 and before exposure with the light).

Since the initial water contact angle is 80 ° or more, the outermost layer 16 has a high surface hydrophobicity in the initial stage, and hydrophobic stains such as oily and dirt stains and EVA are difficult to adhere and are removed even if they adhere. It exhibits easy antifouling properties. In addition, since the water contact angle after exposing light with a wavelength of 300 to 800 nm at an irradiance of 650 W / m ² for 1000 hours is 76 ° or less, the structural change due to ultraviolet rays after the article 10 is installed outdoors or the like. As a result, the hydrophobicity of the surface of the outermost layer 16 decreases with time, and traces of running water due to rainwater and the like are less likely to be attached. Therefore, the article 10 can maintain a good appearance over a long period. For example, in the case of transparent substrates for solar cells, particularly cover glass, even if a sealing material (such as EVA) melted in the manufacturing process of the solar cell module adheres, the sealing material can be easily peeled off, and the solar cell module When it is installed outdoors, it is difficult to leave running water traces due to rainwater.

The initial water contact angle is preferably 90 ° or more.
The water contact angle after exposing light having a wavelength of 300 to 800 nm at an irradiance of 650 W / m ² for 1000 hours is preferably 60 ° or less.
The measuring method of these water contact angles is as showing in the Example mentioned later.
These water contact angles can be adjusted by the material constituting the outermost layer. For example, when a film is formed with the compound, it is a hydrophobic compound having a water contact angle of 80 ° or more immediately after formation, and decomposes when light having a wavelength of 300 to 800 nm is irradiated at an irradiance of 650 W / m ^2. And the outermost layer which has said characteristic can be formed by using the compound which has the ultraviolet-decomposability which hydrophobicity falls.

In the present embodiment, the outermost layer 16 is preferably a layer composed of a silicone polymer that satisfies the following conditions (1) and (2).
(1) A copolymer of the compound (X) represented by the following general formula (x) and the compound (Y) represented by the following general formula (y),
The molar ratio (Y / (X + Y)) of the compound (Y) to the total amount of the compound (X) and the compound (Y) is 0.2 to 0.8.
(2) The weight average molecular weight is 750 to 5000.

Si (OR ¹ ) ₄ (x)
R ³ Si (OR ² ) ₃ (y)
[Wherein R ¹ is an alkyl group having 1 to 3 carbon atoms, and a plurality of R ¹ in the formula may be the same or different, and R ² is an alkyl group having 1 to 3 carbon atoms. And a plurality of R ² in the formula may be the same or different, and R ³ is a hydrocarbon group having 1 to 20 carbon atoms. ]

Compound (X) and compound (Y) are each hydrolyzed in the presence of water, and Si—OR ¹ and Si—OR ² become Si—OH, respectively. The produced hydrolysates are condensation polymerized to form a silicone polymer.
R ³ in the compound (Y) is introduced as it is into the silicone polymer. By having a structure in which one R ³ is bonded to one Si at a predetermined ratio and having a predetermined weight average molecular weight, the silicone polymer has water repellency and ultraviolet decomposability.
Therefore, immediately after formation, the outermost layer 16 has a high surface hydrophobicity, and hydrophobic stains such as fat and oil stains and EVA hardly adhere to them, and exhibits antifouling properties that are easy to remove even if they adhere. On the other hand, after the article 10 is installed outdoors or the like, the hydrophobicity of the surface decreases with time due to structural changes due to ultraviolet rays, and traces of running water due to rainwater and the like are less likely to be attached. Therefore, the article 10 can maintain a good appearance over a long period.
In addition, when the overcoat liquid containing the silicone polymer is applied to the surface of the silica-based porous film, even if there are open pores on the surface of the silica-based porous film, the overcoat liquid is immersed in the silica-based porous film. When the outermost layer 16 is formed by application of an overcoat solution, the antireflection performance of the silica-based porous film is deteriorated and the appearance is hardly deteriorated.

Compound (X) 4 one of R ¹ having the may be the same or different. The same group is preferable in terms of easy availability, hydrolysis, ease of control of the condensation polymerization reaction, and the like.
Specific examples of compound (X) include, for example, tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc.) and the like. These may be used alone or in combination of two or more.

Compound (Y) 3 single R ² having the may be the same or different. The same group is preferable in terms of easy availability, hydrolysis, ease of control of the condensation polymerization reaction, and the like.
R ³ is a hydrocarbon group having 1 to 20 carbon atoms. The hydrocarbon group preferably has 6 to 16 carbon atoms.
When the number of carbon atoms is 20 or less, when an overcoat solution is prepared, precipitation does not easily occur in the overcoat solution, and the appearance after coating becomes good. As the number of carbon atoms is larger within the above range, the penetration of the overcoat liquid into the silica-based porous film 14 is less likely to occur.
Examples of the hydrocarbon group for R ³ include an alkyl group, an aryl group, an aralkyl group, an alkenyl group, and an alkynyl group.
The alkyl group may be linear, branched or cyclic, and is preferably linear from the viewpoint of cost and material selectivity. 1-20 are preferable and, as for carbon number of this alkyl group, 6-16 are more preferable.
Examples of the aryl group include a phenyl group.
The hydrocarbon group for R ³ may have a substituent. Examples of the substituent include an amine group, an epoxy group, and a mercapto group.

Specific examples of the compound (Y) include monoalkyltrialkoxysilane (methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, hexyltri). Methoxysilane, decyltrimethoxysilane, hexadecyltrimethoxysilane, vinyltrimethoxysilane, etc.), monoaryltrialkoxysilane (phenyltrimethoxysilane, phenyltriethoxysilane, styryltrimethoxysilane, etc.), vinyltriethoxysilane, glycine Sidoxypropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrime Toxisilane, 3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane and the like can be mentioned. These may be used alone or in combination of two or more.
Of the above, the compound (Y) is preferably a monoalkyltrialkoxysilane having an alkyl group having 6 to 16 carbon atoms as R ³ because of excellent UV decomposability.

  The silicone polymer can be produced by a conventional method except that the compound (X) and the compound (Y) are used in a predetermined molar ratio. For example, it can be produced by performing a hydrolysis / polycondensation reaction under acidic or basic conditions. In addition, you may hydrolyze and polymerize a compound (X) and a compound (Y) each independently, and may mix these after that.

The molar ratio (Y / (X + Y)) of the compound (Y) to the total amount of the compound (X) and the compound (Y) is 0.2 to 0.8, preferably 0.2 to 0.7, 0 .3 to 0.7 is more preferable.
If Y / (X + Y) is 0.2 or more, the surface of the outermost layer 16 immediately after formation has high hydrophobicity and excellent antifouling properties. When Y / (X + Y) is 0.8 or less, it is difficult for the overcoat liquid to penetrate into the silica-based porous film 14, and the antireflection performance is less likely to be lowered after coating. Further, the outermost layer 16 can be formed with a sufficient thickness, and the antifouling property is sufficiently exhibited.

The weight average molecular weight of the silicone polymer is 750 to 5000, preferably 1000 to 3000.
When the weight average molecular weight is 750 or more, it is difficult for the overcoat liquid to penetrate into the silica-based porous film 14. When the weight average molecular weight is 5000 or less, when an overcoat solution is prepared, precipitation does not easily occur in the overcoat solution, and the appearance after coating becomes good.

The outermost layer 16 may contain components other than the silicone polymer as long as the effects of the present invention are not impaired.
Examples of the other components include fine particles such as silica, titania and zirconia, and organic polymers such as polyethylene glycol and polyvinyl alcohol.

  The thickness of the outermost layer 16 is preferably 3 to 20 nm, and more preferably 5 to 15 nm. When it is 3 nm or more, the antifouling property against the hydrophobic stain immediately after the formation of the outermost layer 16 is excellent. When the thickness is 20 nm or less, the change in the maximum transmittance due to the provision of the outermost layer 16 is small.

The article 10 preferably has a Tmax (%) at a wavelength of 400 to 1100 nm of Tmax (%) at a wavelength of 400 to 1100 nm of the transparent substrate 12 + 2.0% or more.
The value of “Tmax of the article 10” − “Tmax of the transparent substrate 12”, that is, the amount of increase in Tmax due to the provision of the silica-based porous film 14 and the outermost layer 16 on the surface of the transparent substrate 12 (hereinafter “after OC” The larger the “ΔTmax”.), The higher the antireflection performance of the silica-based porous film 14 and the lower the antireflection performance due to the outermost layer 16.
ΔTmax after OC is preferably 2% or more.

The refractive index of the outermost layer 16 is preferably 2.0 or less, and more preferably 1.6 or less. When the refractive index is 2.0 or less, it is possible to suppress a decrease in antireflection performance due to the outermost layer 16.
The refractive index of the outermost layer 16 can be measured by performing curve fitting based on the reflectance spectrum of a film applied on the transparent base material 12 with a known refractive index under conditions of known film thickness.

(Method for manufacturing article 10)
The article 10 includes a step of forming the silica-based porous film 14 on the transparent substrate 12, and a step of applying an overcoat liquid to the surface of the silica-based porous film 14 and drying to form the outermost layer 16 And can be manufactured.

  The formation of the silica-based porous film 14 can be performed by a known manufacturing method depending on the silica-based porous film to be formed, but is preferably performed by the manufacturing method I described later. According to the production method I, the silica-based porous film 14 ′ (a film having a two-layer structure composed of the dense layer 14-1 and the non-dense layer 14-2) shown in FIG. 2 can be easily formed.

The overcoat liquid for forming the outermost layer 16 includes a component constituting the outermost layer 16 and a solvent.
As the component constituting the outermost layer 16, the silicone polymer is preferable because the penetration of the overcoat liquid into the silica-based porous film 14 can be suppressed.
The content of the silicone polymer in the overcoat liquid is not particularly limited as long as the overcoat liquid can be applied, but as a solid content concentration in terms of SiO _{2 with} respect to the total amount (100% by mass) of the overcoat liquid. 0.01 to 20 mass% is preferable, and 0.02 to 5.0 mass% is more preferable. When it is 0.01% by mass or more, the antifouling performance is sufficiently exhibited because it is easily coated with the silicone polymer, and when it is 20% by mass or less, the influence on the antireflection performance is small.

The solvent for the overcoat liquid may be any solvent that can dissolve the compounds (X), (Y) and the silicone polymer, and even a single liquid may be a mixture of two or more liquids. Also good.
Since water is required for hydrolysis of the compounds (X) and (Y), the solvent 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, alcohols are preferable, and methanol and ethanol are particularly preferable.

The overcoat liquid may contain other components other than the silicone polymer as long as the effects of the present invention are not impaired.
Examples of the other components include fine particles such as silica, titania and zirconia, and organic polymers such as polyethylene glycol and polyvinyl alcohol.

The overcoat solution can be prepared by a conventional method. For example, the compounds (X) and (Y) are dissolved in a predetermined molar ratio in a solvent containing water, hydrolyzed and polycondensed to form a silicone polymer, and then diluted with a solvent as necessary. Thus, an overcoat solution can be prepared.
At this time, the weight average molecular weight of the silicone polymer to be produced can be adjusted by adjusting the conditions such as the concentrations of the compounds (X) and (Y), the amount of water added, the reaction temperature, and the reaction time.
The terms of SiO ₂ solids at the time of polymerizing the silicone polymer is preferably 1 to 20 wt%, and more preferably from 2 to 18 wt%. If it is 1% by mass or more, the hydrolysis polycondensation reaction of the compounds (X) and (Y) proceeds sufficiently, and if it is 20% by mass or less, the hydrolysis polycondensation reaction can be easily controlled, and further the coating solution The long-term storage stability is good. Incidentally, SiO ₂ in terms of solids, the compounds used as a raw material for the silicone polymer (X), a solids content of when all the Si (Y), was converted to SiO _2.

As a method for applying the overcoat liquid, known wet coat methods (spin coat method, spray coat method, dip coat method, die coat method, curtain coat method, screen coat method, ink jet method, flow coat method, gravure coat method, bar (Coating method, flexo coating method, slit coating method, roll coating method, sponge coating method, etc.) can be used.
The coating temperature is preferably 10 to 100 ° C, and more preferably 20 to 80 ° C.
The drying after the application only needs to remove the solvent. For example, the outermost layer 16 is formed by heating and drying in a baking furnace at 200 ° C. for 1 minute.

{Production method I of transparent substrate with silica-based porous film I}
A method I for producing a transparent substrate with a silica-based porous film comprises a coating liquid containing a matrix precursor (A) shown below, particles (B) removable from the matrix, and a liquid medium (C). And a step of applying heat treatment to the surface of the transparent substrate 12.
The matrix 21 is formed from the matrix precursor (A) by heat-treating the coating film of the 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 film 14 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 21 is set to the thermal decomposition temperature of the thermally decomposable material. By setting the above temperature, the particles (B) are vaporized, pass through the fine pores in the matrix 21 and are released to the outside of the matrix 21, and the silica-based porous film 14 is formed. The heat treatment for forming the matrix 21 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 film 14 is subjected to a removal treatment according to the material constituting the particles (B) before or after the matrix 21 is formed by the heat treatment. Can be formed.

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, a dense layer 14-1 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 conceivable that. 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 average film thickness of the dense layer 14-1 is increased. 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 average film thickness of 14-1 tends to increase. Therefore, the compound (a1) is preferably a tetraalkoxysilane having 1 or 2 carbon atoms in the alkoxy group, and particularly preferably tetramethoxysilane, among tetraalkoxysilanes.

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 solution is usually used as it is or after appropriately diluted to prepare the coating solution. 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 5 degreeC or more, a hydrolysis polycondensation reaction will fully advance, and if it is 80 degrees C or less, control of a hydrolysis polycondensation reaction 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 represents a non-hydrolyzable group in which the dielectric constant of Y—OH is 50 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) is selected as a similar compound of the hydrolyzate and partial condensate Si—OH of compound (a1), and Y—OH is selected as the hydrolyzate and partial condensate of compound (a2). did. 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 14-1 is easily formed. The dielectric constant of Y—OH is preferably 35 F / m or less.

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 is determined by applying an electric field to the sample by a bridge circuit using a network analyzer (manufactured by Agilent Technologies, PNA microwave vector network analyzer) in accordance with the provisions of JIS-R1627, and reflecting coefficient And the phase was 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, etc.), 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). In addition, the compounds (a1) and (a2) may be mixed in advance to perform a cohydrolysis polycondensation reaction.

In the matrix precursor (A), the content ratio between the compound (A1) and the compound (A2) is converted into the molar ratio ((a1) / (a2)) between the compound (a1) and the compound (a2). Thus, it is preferably within the range of 0.1 to 3.0, and more preferably within the range of 0.2 to 2.0.
By setting the value of (a1) / (a2) to 3.0 or less, the dense layer 14-1 is formed with a sufficient thickness, and the number of open pores on the outermost surface of the silica-based porous film 14 ′ is about 1000 nm × 1000 nm. It can be 16 or less. Moreover, the smoothness of the surface 14a is high, and arithmetic mean roughness Sa can be made low (for example, 3.0 nm or less). Since the number of open pores on the outermost surface of the silica-based porous film 14 ′ is small, the overcoat liquid is difficult to penetrate. Further, excellent moisture resistance can be obtained. Moreover, since the surface smoothness of the silica type porous membrane 14 is high, the surface smoothness of the outermost layer 16 formed on it also becomes high, and antifouling property, abrasion resistance, etc. improve.
When the value of (a1) / (a2) is 0.1 or more, sufficient antireflection performance can be obtained.

  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 200 or more, volatilization of unreacted components is suppressed, and if it is 2000 or less, sufficient transparency can be secured. The average molecular weight can be controlled by the amount of water added, the reaction temperature, the content of the 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 coating solution is not particularly limited as long as the coating solution can be applied, but as a solid content concentration in terms of SiO _{2 with} respect to the total amount (100% by mass) of the coating solution. 0.2-20 mass% is preferable and 0.5-15 mass% is more preferable. If it is 0.2% by mass or more, the hydrolysis polycondensation reaction proceeds sufficiently, and if it is 20% by mass or less, the hydrolysis polycondensation reaction can be easily controlled and the long-term storage stability is good.
Incidentally, SiO ₂ in terms of solids are solids when all the Si matrix precursor contained in the coating liquid (A) was converted to SiO _2.

The particles (B) are particles that can be removed from the matrix, for example, particles that can be removed by heat treatment, particles that can be removed by plasma treatment, particles that can be removed by solvent immersion, particles that can be removed by acid or alkali immersion, Examples thereof include particles that can be removed by light irradiation.
Since heat treatment is required to form the dense layer 14-1, the particles (B) are preferably particles that can be removed by heat treatment, but before or after the heat treatment, plasma treatment, solvent immersion, acid or alkali immersion, Alternatively, the dense layer 14-1 may be formed by heat treatment after removal by light irradiation.

Examples of particles 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 easily 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-chloroacrylate Chill, 2-chloroethyl methacrylate, acrylonitrile, methacrylonitrile, methacrylamide, N-methylol methacrylamide, N-methoxyethyl methacrylamide, N-butoxymethyl methacrylamide, aminoethyl (meth) acrylate, (meth) Propylaminoethyl acrylate, dimethylaminoethyl methacrylate, aminopropyl (meth) acrylate, phenylaminoethyl methacrylate, cyclohexylaminoethyl methacrylate, alkyl ester derivatives of acrylic acid or methacrylic acid, N-vinyldiethylamine, N- Vinylamine derivatives such as acetylvinylamine, allylamine, methacrylamine, N-methylacrylamine, N, N-dimethylacrylamide, N, N-dimethylaminopropyl Allylamine derivatives such as acrylamide, acrylamide derivatives such as acrylamide and N-methylacrylamide, p-aminostyrene, N-methylol (meth) acrylamide and diacetone acrylamide, 6-aminohexyl succinimide, 2-aminoethyl succinic acid Imides, 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 glycidyl esters of allyl succinic acid, and the like Ricidyl ester, alkyl glycidyl ester of p-styrene carboxylic acid, allyl glycidyl ether, glycidyl ether acrylate, glycidyl methacrylate, -2-ethyl glycidyl acrylate, 2-ethyl glycidyl methacrylate Tail, 2-methylallyl glycidyl ether, styrene-p-glycidyl ether, glycidyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, acrylic acid or methacrylic acid Monoester of acid and polypropylene glycol or polyethylene glycol, adduct of lactone and 2-hydroxyethyl (meth) acrylate, trifluoromethyl methyl (meth) acrylate, (meth) acrylate 2-trifluoromethyl ethyl oxalate, (meth) acrylic acid-2-perfluoromethyl ethyl, (meth) acrylic acid-2-perfluoroethyl-2-perfluorobutyl ethyl, (meth) acrylic acid 2-perfluoroethyl, perfluoromethyl (meth) acrylate, dipa-fluoromethyl methyl (meth) acrylate, vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl isobutyrate, vinyl pivalate, capron Vinyl acetate, vinyl persate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pt-butyl benzoate, vinyl salicylate, vinylidene chloride, vinyl chlorohexanecarboxylate, 2-chloroethyl acrylate, methacrylic acid 2-chloroethyl, 3-chloro-2-hydroxypropyl 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-trishydroxymethylpro Down 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 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 include the organic polymers described above.
The particles that can be removed by immersion in the solvent can be dissolved and removed by immersing the film made of the matrix precursor (A) and the particles (B) in the solvent. Examples of the material of the particles include diglyme, N, N-dimethylformamide, N, N-dimethylacetamide, ethyl acetate, ethyl acetoacetate, N-methyl-2-pyrrolidinone, 2-pyrrolidinone, 1,3-dimethyl- Polystyrene as soluble in solvents such as 2-imidazolidinone, dimethyl sulfoxide, toluene, xylene, benzene, trichlene, mineral spirits, benzol, xylol, γ-butyrolactone, tetrahydrofuran, methyl ethyl ketone, acetone, dichloromethane, chloroform, methylene chloride And polymethyl acrylate.
Particles that can be removed by acid or alkali immersion can be dissolved and removed by immersing a film composed of the matrix precursor (A) and 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 that can be removed by light irradiation can be removed from the matrix by irradiating light (for example, ultraviolet rays, etc.) to the film composed of the matrix precursor (A) and the particles (B) 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, a heat treatment is performed before and / or after the step of removing the particles (B) in order to form the dense layer 14-1. Preferably it is done.

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 preferably 20 to 130 nm, more preferably 30 to 130 nm, and further preferably 30 to 100 nm. When the average primary particle diameter of the particles (B) is 20 nm or more, a silica-based porous film having pores with a 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 16 per 1000 × 1000 nm. It tends to be below nm. Moreover, when the average primary particle diameter of the particles (B) is in the range of 20 to 130 nm, the average pore diameter is likely 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 coating solution is such that the mass ratio ((A) / (B)) between the content of the matrix precursor (A) in terms of SiO _{2 and} the content of the particles (B) is 0. The amount is preferably in the range of 3 to 4.0, and more preferably in the range of 0.5 to 3.0.
When (A) / (B) is 4.0 or less, the porosity in the silica-based porous film 14 is sufficiently high, and the refractive index of the silica-based porous film 14 ′ is sufficiently low (for example, 1. 38 or less). When (A) / (B) is 0.3 or more, the porosity in the silica-based porous membrane 14 ′ does not become too high, and the durability is excellent.

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 and ethanol 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 solution may contain other 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).

  Examples of the method for preparing the coating liquid include a method of mixing a solution of the matrix precursor (A) and a dispersion of the particles (B), and more specifically, the following methods (α) to (γ): Is mentioned. Among these, the method (β) is preferable because the compound (a2) tends to float on the surface of the coating film when the coating liquid is applied to the surface of the transparent substrate 12. 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, then 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), the 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.

As a coating method of the coating liquid, 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) Method, flexo coat method, slit coat method, roll coat method, sponge coat method, etc.).
The coating temperature is preferably 10 to 100 ° C, and more preferably 20 to 80 ° C.

What is necessary is just to determine the heat processing temperature suitably according to the transparent base material 12, particle | grains (B), or a matrix precursor (A).
In order to use the matrix precursor (A) as the matrix 21, 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. When the heat treatment temperature is 100 ° C. or higher, the matrix 21 is densified and the durability is improved. When the heat treatment temperature is 700 ° C. or lower, when the transparent substrate 12 is a glass plate, the alkali diffusion from the glass can be kept low, and the moisture resistance is good.
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 using the matrix precursor (A) as the matrix 21 may be performed at a temperature lower than the thermal decomposition temperature before the heat treatment.
When the transparent substrate 12 is a glass plate, 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 removal 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 manufacturing method I described above, the distribution state of the pores 22 is achieved by performing the series of steps of applying the coating liquid on the transparent substrate 12, heat-treating, and removing the particles (B) once. A silica-based porous film 14 having a structure in which two different layers (dense layer 14-1 and non-dense layer 14-2) are laminated 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 coating solution containing the compound (A1) and the compound (A2) is applied to the surface of an article such as a glass plate, the compound (A2) floats in the coating film, and as a result, the upper phase (compound (A2) phase) And the 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 film 14 having pores 22 having a shape corresponding to the shape of (B) is formed.

  Therefore, in the silica-based porous film 14 formed as described above, it is considered that the dense layer 14-1 and the non-dense layer 14-2 have different compositions in the matrix 21. That is, the matrix 21 constituting the dense layer 14-1 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 21 constituting the non-dense layer 14-2 is substantially composed of a heat-treated product of the compound (A1), and does not contain or contains very little structure derived from the compound (A2).

According to said manufacturing method I, the refractive index of the silica type porous membrane 14 formed can be 1.38 or less. The lower the refractive index, the lower the reflectance and the better the antireflection performance.
Moreover, according to said manufacturing method I, the arithmetic mean roughness of the silica type porous membrane 14 formed can be 3.0 nm or less. The smaller the arithmetic average roughness, the better the wear resistance, antifouling property, etc., and the more useful as an antireflection film.
As one of known methods for producing a silica-based porous membrane, there is a method of applying and heat-treating a coating solution in which hollow silica fine particles are dispersed in a matrix precursor solution. In the case of this method, if the size of the hollow silica fine particles is small, it is possible to form a silica-based porous film having a surface open pore number of 16 or less per 1000 nm × 1000 nm. However, when the size of the hollow silica fine particles is increased in order to make the refractive index 1.38 or less (for example, the internal pore diameter is 20 nm or more), pores having a diameter of 20 nm or more are formed between the hollow silica fine particles, A hole opens in the outermost surface. Moreover, since the shape of the hollow silica fine particles is reflected on the outermost surface, the arithmetic average roughness (Sa) tends to be larger than 3 nm.
The arithmetic average roughness (Sa) is measured in a measurement range of 10 μm × 10 μm using a scanning probe microscope apparatus (for example, SPA400DFM, manufactured by SII Nano Technology).

  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.

By providing the outermost layer in the article of the present invention, the antifouling property is enhanced while maintaining the antireflection performance of the silica-based porous film, and a good appearance can be maintained over a long period of time.
Articles of the present invention include transparent parts for vehicles (headlight covers, side mirrors, front transparent boards, side transparent boards, rear transparent boards, etc.), transparent parts for vehicles (instrument panel surfaces, etc.), meters, architectural windows, Show window, display (notebook PC, monitor, LCD, PDP, ELD, CRT, PDA, etc.), LCD color filter, touch panel substrate, pickup lens, optical lens, spectacle lens, camera component, video component, CCD cover substrate , 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.
Among the above, in the case of transparent substrates for solar cells, particularly cover glass, it is possible to prevent adhesion of sealing materials (such as EVA) melted in the manufacturing process of solar cells, and when installed outdoors as solar cell modules In addition, antifouling properties are difficult to prevent traces of running water due to rainwater or the like. Since the article of the present invention satisfies such a requirement, it is highly useful as a transparent substrate for solar cells.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
Of Examples 1 to 25 described later, Examples 2-3, 5-7, 11-15, 18, 21-23 are examples, and Examples 1, 4, 8-10, 16-17, 19, 20, 24 to 25 are comparative examples.
The measurement method and evaluation method used in each example are shown below.

(Weight average molecular weight of silicone polymer)
The weight average molecular weight (Mw) in terms of polystyrene was measured by gel permeation chromatography (GPC).

(Number of open pores on the outermost surface of the silica-based porous membrane)
The number of open pores on the outermost surface is determined by applying the outermost surface on the silica porous membrane side of the glass plate with the silica porous membrane produced in each example to a scanning electron microscope SEM (manufactured by Hitachi, Ltd., model: S-4300). From the obtained image, the number of openings having a diameter of 20 nm or more existing in a region of 1000 nm × 1000 nm was measured.

(Outermost layer thickness)
The overcoat liquid for the outermost layer was applied onto soda lime glass, and the film thickness was calculated using a reflection spectral film thickness meter (manufactured by Otsuka Electronics Co., Ltd., FE-3000CWA).

(Maximum transmittance change)
For the glass plate (“Solite” manufactured by Asahi Glass Co., Ltd.) before forming the silica-based porous film, the transmittance of light incident on the surface at an incident angle of 0 ° was measured with a spectrophotometer (manufactured by Hitachi, Ltd., model: U-4100). ) To obtain the maximum transmittance (hereinafter “base Tmax”) (%) within a wavelength range of 400 to 1100 nm. 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.
For a glass plate with a silica-based porous film in which a silica-based porous film is formed on the surface of the glass plate, light incident at an incident angle of 0 ° on the surface of the silica-based porous film side (the side opposite to the glass plate side) The transmittance was measured in the same manner as described above, and the maximum transmittance (hereinafter referred to as “Tmax before OC”) (%) in the wavelength range of 400 to 1100 nm was determined.
For an article having an outermost layer formed on the surface of the silica-based porous film of the glass plate with the silica-based porous film, light incident on the surface on the outermost layer side (opposite side of the glass plate side) at an incident angle of 0 ° The transmittance was measured in the same manner as described above, and the maximum transmittance (hereinafter referred to as “Tmax after OC”) (%) within a wavelength range of 400 to 1100 nm was determined.

From the above measurement results, the value of Tmax before OC-base Tmax (hereinafter referred to as "ΔTmax before OC"), the value of Tmax after OC-base Tmax (hereinafter referred to as "ΔTmax after OC"), the value of Tmax after OC-Tmax before OC (hereinafter referred to as "Tmax"). The value of “ΔTmax change amount before and after OC” was calculated.
The larger the value of ΔTmax (ΔTmax before OC, ΔTmax after OC), the higher the antireflection performance. Further, the closer the amount of change in ΔTmax before and after OC is to 0 (the value of ΔTmax after OC is closer to ΔTmax before OC), the less the outermost layer has an influence on the antireflection performance of the silica-based porous film.
In the present invention, ΔTmax before OC is preferably 2.80% or more, and more preferably 2.90% or more.
ΔTmax after OC is preferably 2.0% or more, and more preferably 2.1% or more.
The amount of change in ΔTmax before and after OC is preferably within a range of −1.2 to 0%, and more preferably within a range of −1.0 to 0%.

(Film refractive index at a wavelength of 550 nm)
When a silica-based porous film was formed on a glass plate to obtain a glass plate with a silica-based porous film, the average total film thickness of the silica-based porous film was measured by the above method.
About this glass plate with a silica type porous membrane, the spectral reflectance curve (spectral curve) was measured using the spectrophotometer. The refractive index of the silica-based porous film was calculated by performing curve fitting based on this spectral curve and the average total film thickness of the silica-based porous film measured above. When the functional layer was previously formed on the surface of the glass plate, first, the refractive index of the functional layer was calculated by the same method as described above, and curve fitting was performed using a film configuration including the functional layer. The calculated refractive index of the silica-based porous film was defined as “film refractive index before OC”.
After forming the outermost layer on the silica-based porous film, the refractive index of the obtained article was calculated in the same manner as described above. The calculated refractive index was defined as “film refractive index after OC”.
Since the film thickness of the outermost layer is extremely thin, the film refractive index after OC measured in this measurement can be regarded as the refractive index of the multilayer film in which the silica-based porous film and the outermost layer are laminated.
When the overcoat liquid for the outermost layer is immersed in the silica-based porous layer, the refractive index increases due to the decrease in the internal void ratio. Therefore, the smaller the refractive index change (film refractive index after OC-film refractive index value before OC) before and after the formation of the outermost layer, the smaller the penetration of the outermost layer coating liquid.

(Water contact angle)
For the article obtained in each example, approximately 48 μL of distilled water droplets were placed at three locations on the surface on the outermost layer side (opposite the glass plate side), and the contact angle of each droplet was determined as Measurement was made using a goniometer (manufactured by Kyowa Interface Science Co., Ltd., FAMAS), and the average of the three values was determined.

[Preparation of coating liquid for forming silica-based porous film]
Coating liquids 1-1 and 1-2 for forming a silica-based porous film were prepared by the following procedure.
To Solmix AP1 (trade name, manufactured by Nippon Alcohol Sales, industrial ethanol), water and nitric acid are added in this order, and then tetramethoxysilane and phenyltrimethoxysilane are added and stirred at room temperature for 1 hour. A precursor solution was prepared.
At this time, water and nitric acid were added so that the concentration in the total amount (100% by mass) of the precursor solution would be 11.31% by mass and 0.053% by mass, respectively. Tetramethoxysilane and phenyltrimethoxysilane have a total solid content concentration in terms of silica of 3% by mass in the total amount of the precursor solution (100% by mass), and the molar ratio (tetramethoxysilane: phenyltrimethoxysilane) is the coating liquid 1 In the case of -1, it was added to be 4: 6, and in the case of the coating liquid 1-2, it was added to be 6: 4.

Next, to Solmix AP1, 10 parts by mass of isobutyl alcohol, 5 parts by mass of diacetone alcohol, 32.67 parts by mass of the precursor solution, and polymer fine particle sol (manufactured by Nippon Shokubai, Eposter MX-050W) 4.2. The coating liquid 1-1, 1-2 was obtained by adding 3 parts by mass and stirring at room temperature for 3 minutes. The amount of Solmix AP1 was such that the total amount of the coating solution was 100 parts by mass.
The material of the polymer particles contained in the polymer fine particle sol was polymethyl methacrylate, and the average primary particle diameter of the polymer particles was 50 nm as measured by the following procedure.
After the polymer fine particle sol was diluted with water to a solid content concentration of 0.1% by mass, it was sampled on the collodion film and observed with a transmission electron microscope (Hitachi, Ltd., model: H-9000). Particles were randomly selected and the average value of the diameters of the particles was defined as the average primary particle diameter of the particles.

[Examples 1-3]
(1. Formation of silica-based porous film)
Using the spin coater on the surface of the glass plate ("Solite" manufactured by Asahi Glass Co., Ltd., low iron content glass), the coating liquid 1-1 for forming the silica-based porous film prepared above is used at 500 rpm for 20 seconds. After coating at 650 ° C., baking was performed at 650 ° C. for 10 minutes, followed by slow cooling at 200 ° C. for 7 minutes to form a silica-based porous film to obtain a glass plate with a silica-based porous film.
The outermost surface numerical aperture of the formed silica-based porous film was 14/1000 nm × 1000 nm. Moreover, the pores in the silica-based porous film were independent pores.

(2. Formation of outermost layer)
The following three types were prepared as overcoat liquids for the outermost layer.
Overcoat liquid a: A polydimethylsiloxane (KF-96-1000cs, Mw25000, manufactured by Shin-Etsu Silicone Co., Ltd.) diluted with hexane to a solid content concentration of 0.5% by mass.

Overcoat solution b: A solution of a copolymer of tetramethoxysilane and methyltrimethoxysilane (Mw850) prepared by the following procedure.
Water and nitric acid are added to Solmix AP1 (trade name, manufactured by Nippon Alcohol Sales, industrial ethanol) in this order, and then tetramethoxysilane as compound (X) and methyltrimethoxy as compound (Y). Silane was added and stirred at room temperature for 1 hour to prepare a precursor solution. At this time, water and nitric acid were added so that the content in the total amount (100% by mass) of the precursor solution would be 11.31% by mass and 0.053% by mass, respectively. Tetramethoxysilane and methyltrimethoxysilane have a total solid content concentration of 2.2% by mass in terms of silica in the total amount (100% by mass) of the precursor solution, and the methyl relative to the total number of moles of tetramethoxysilane and methyltrimethoxysilane. Trimethoxysilane was added so that the molar ratio (Y / (X + Y)) was 0.5. The weight average molecular weight of the silicone polymer was measured at the end of stirring for 1 hour.
The obtained precursor solution was diluted with 2-propanol so that the solid concentration in terms of silica was 0.5% by mass to obtain an overcoat liquid b.

Overcoat liquid c: A solution of a copolymer of tetraethoxysilane and decyltrimethoxysilane (Mw1942).
The overcoat liquid c was prepared in the same procedure as the coating liquid b except that an equimolar amount of decyltrimethoxysilane was used instead of methyltrimethoxysilane.

  Each overcoat solution was applied to the surface of the silica-based porous membrane side of the glass plate with the silica-based porous membrane obtained above using a spin coater under the conditions of 2000 rpm and 30 seconds, and then at 160 ° C. for 30 minutes. By drying and solidifying, the outermost layer was formed into a desired article.

Evaluation results of maximum transmittance change amount in each example (ΔTmax before OC, ΔTmax after OC, ΔTmax change amount before and after OC), film refractive index before and after OC, film thickness of outermost layer, outermost layer immediately after manufacturing Table 1 shows the measurement results of the water contact angle (initial contact angle).
The obtained article was exposed with a UV acceleration tester (Toyo Seiki Seisakusho, Suntest XLS). The water contact angle after exposure for 475 hours (contact angle after 475 hours) and the water contact angle after exposure for 1308 hours (contact angle after 1308 hours) were measured by the above procedure. The results are shown in Table 1.
Furthermore, a plot consisting of at least one point each of the initial contact angle, the contact angle after 300-800 hours exposure, and the contact angle after 1000-1500 hours exposure was approximated by the least square method to obtain a converted value after 1000 hours exposure. The water contact angle (1000 hours exposure conversion contact angle) was determined. The results are shown in Table 1.
In Table 1, the organic group (type and number of organic groups bonded to one Si atom) of the silicone polymer contained in each overcoat liquid is also shown.

As shown in the above results, the articles of Examples 2 and 3 in which the outermost layer was formed using the overcoat liquids b and c had a film refractive index after OC of 1.428 or less and an initial contact angle of the outermost layer of 80. More than °. Further, after exposure for 1308 hours, the water contact angle of the outermost layer decreased to 76 ° or less, and it had UV decomposability. If it has such UV decomposability, it will exhibit antifouling properties against hydrophobic stains in the initial stage, and the appearance will be excellent over a long period of time by decreasing the hydrophobicity (improving hydrophilicity) over time. Can be maintained.
On the other hand, in the article of Example 1 in which the outermost layer was formed using the overcoat liquid a, the water contact angle of the outermost layer exceeded 90 ° even after exposure for 1308 hours.

[Examples 4 to 19]
(1. Formation of silica-based porous film)
Using the spin coater on the surface of the glass plate ("Solite" manufactured by Asahi Glass Co., Ltd.), the coating liquid prepared above (Examples 1-18 is coating liquid 1-1, Example 19 is coating liquid 1-2), After applying for 20 seconds, firing is performed at 650 ° C. for 10 minutes, followed by slow cooling at 200 ° C. for 7 minutes to form a silica-based porous film, and the glass plate with the silica-based porous film is formed. Obtained.
The outermost surface numerical aperture of the silica-based porous film formed using the coating liquid 1-1 is 14/1000 nm × 1000 nm, and the outermost surface open pore number of the antireflection film formed using the coating liquid 1-2 is 20 pieces / 1000 nm × 1000 nm. Moreover, the pores in the silica-based porous film were independent pores.

(2. Formation of outermost layer)
An overcoat solution was prepared by the following procedure.
Water and nitric acid are added in this order to Solmix AP1 (trade name, manufactured by Nippon Alcohol Sales, industrial ethanol), and then tetramethoxysilane as compound (X) and hexyltrimethoxy as compound (Y). Silane was added and stirred at room temperature for 24 hours to prepare a precursor solution. At this time, water and nitric acid were added so that the content in the total amount (100% by mass) of the precursor solution would be 11.31% by mass and 0.053% by mass, respectively. Tetramethoxysilane and hexyltrimethoxysilane are solid concentrations (mass%) in terms of silica in the total amount (100 mass%) of the precursor solution, and the concentrations at the time of polymerization shown in Tables 2 to 4, tetramethoxysilane and hexyltrimethoxy. It added so that the ratio (Y / (X + Y)) of the number of moles of hexyltrimethoxysilane with respect to the total number of moles with silane might become the value shown in Tables 2-4.
The obtained precursor solution was diluted with 2-propanol so that the solid content concentration in terms of silica was 0.25% by mass to obtain an overcoat solution.
The prepared overcoat solution is applied to the surface of the glass plate with the silica-based porous membrane on the silica-based porous membrane side using the spin coater under the conditions of 2000 rpm and 30 seconds, followed by 30 at 160 ° C. The outermost layer was formed by drying and solidifying for a minute to obtain the desired article.

Evaluation results of maximum transmittance change amount in each example (ΔTmax before OC, ΔTmax after OC, ΔTmax change amount before and after OC), film refractive index before and after OC, film thickness of outermost layer, outermost layer immediately after manufacturing Tables 2 to 4 show the measurement results of the contact angle (initial contact angle).
In Example 8, since the outermost layer was not formed, ΔTmax after OC and ΔTmax change amount before and after OC were not evaluated. Moreover, the initial contact angle measured the contact angle of the silica type porous membrane surface.

When Example 4 is compared with Examples 5 to 7, the articles of Examples 5 to 7 using a silicone polymer having a Mw of 750 to 5000 have a film refractive index after OC of 1.428 or less, and the initial surface layer is the initial layer. The contact angle was 80 ° or more. Further, ΔTmax after OC was 2.0% or more, ΔTmax change amount before and after OC was small, and even when the outermost layer was formed, the antireflection performance of the silica-based porous film was almost maintained.
On the other hand, the article of Example 1 obtained using a silicone polymer having Mw of 730 had a film refractive index after OC of more than 1.428. Further, the ΔTmax change amount before and after the OC was large. This is considered to be because when the outermost layer was formed, the overcoat solution soaked into the antireflection film and the porosity decreased.

When Examples 8 to 10, Example 11 to 15, and Examples 16 to 17 are compared, articles of Examples 11 to 15 using a silicone polymer obtained by setting Y / (X + Y) to 0.2 to 0.8 are OC. The subsequent film refractive index was 1.428 or less, and the initial contact angle of the outermost layer was 80 ° or more. Further, ΔTmax after OC was 2.0% or more, ΔTmax change amount before and after OC was small, and even when the outermost layer was formed, the antireflection performance of the silica-based porous film was almost maintained.
On the other hand, the article of Example 8 in which the outermost layer was not formed (a glass plate with a silica-based porous film), an example using a silicone polymer obtained by setting Y / (X + Y) to 0 (polymerizing only compound (A)) Each of the 9 articles and the article of Example 10 using the silicone polymer obtained by setting Y / (X + Y) to 0.1 had an initial contact angle of less than 80 °.
In the articles of Examples 16 to 17 using the silicone polymer obtained by setting Y / (X + Y) to 0.9 or more, the film refractive index after OC exceeded 1.428. Further, the ΔTmax change amount before and after the OC was large. This is considered to be because when the outermost layer was formed, the overcoat solution soaked into the antireflection film and the porosity decreased.

When Example 18 and Example 19 are compared, the number of open pores on the outermost surface of the silica-based porous membrane is 14 per 1000 nm × 1000 nm, and the article of Example 18 having ΔTmax before OC of 2.90% is the membrane after OC The refractive index was 1.428 or less, and the initial contact angle of the outermost layer was 80 ° or more. Further, the amount of change in ΔTmax before and after OC was small, and even when the outermost layer was formed, the antireflection performance of the silica-based porous film was substantially maintained.
On the other hand, the article of Example 19 in which the number of open pores on the outermost surface of the silica-based porous film is 20 per 1000 nm × 1000 nm and ΔTmax before OC is 2.83% has a film refractive index after OC of 1.428 or less. there were. Further, the ΔTmax change amount before and after the OC was large. Also, the initial contact angle was inferior to Example 18. It is considered that this is because most of the overcoat liquid for forming the outermost layer soaked into the silica-based porous film, the porosity decreased, and the outermost layer having a sufficient thickness could not be formed.

[Examples 20 to 25]
(1. Formation of silica-based porous film)
The coating liquid 1-1 prepared above was applied to the surface of a glass plate ("Solite" manufactured by Asahi Glass Co., Ltd.) using a spin coater under conditions of 500 rpm and 20 seconds, and then baked at 650 ° C for 10 minutes. Then, the silica type porous membrane was formed by performing slow cooling at 200 degreeC for 7 minutes, and the glass plate with a silica type porous membrane was obtained.
The outermost surface numerical aperture of the silica-based porous film formed using the coating liquid 1-1 is 14/1000 nm × 1000 nm, and the outermost surface open pore number of the antireflection film formed using the coating liquid 1-2 is 20 pieces / 1000 nm × 1000 nm. Moreover, the pores in the silica-based porous film were independent pores.

(2. Formation of outermost layer)
Water and nitric acid are added in this order to Solmix AP1 (trade name, manufactured by Nippon Alcohol Sales, industrial ethanol), and then tetramethoxysilane as compound (X) and decyltrimethoxy as compound (Y) Silane was added and stirred at room temperature for 24 hours to prepare a precursor solution. At this time, water and nitric acid were added so that the content in the total amount (100% by mass) of the precursor solution would be 11.31% by mass and 0.053% by mass, respectively. Tetramethoxysilane and decyltrimethoxysilane have a total solid content concentration (mass%) in terms of silica of 10.0% by mass in the total amount of precursor solution (100% by mass), and the total of tetramethoxysilane and decyltrimethoxysilane. It added so that the ratio (Y / (X + Y)) of the number of moles of decyltrimethoxysilane with respect to the number of moles might be 0.50.
The obtained precursor solution was diluted with 2-propanol so that the solid content concentration in terms of silica was a value shown in Table 5 to obtain an overcoat solution.
The prepared overcoat solution is applied to the surface of the glass plate with the silica-based porous membrane on the silica-based porous membrane side using the spin coater under the conditions of 2000 rpm and 30 seconds, followed by 30 at 160 ° C. The outermost layer was formed by drying and solidifying for a minute to obtain the desired article.

  Evaluation results of maximum transmittance change amount in each example (ΔTmax before OC, ΔTmax after OC, ΔTmax change amount before and after OC), film refractive index before and after OC, film thickness of outermost layer, outermost layer immediately after manufacturing Table 5 shows the measurement results of the contact angle (initial contact angle).

When Example 20 is compared with Examples 21 to 23 and Examples 24 to 25, the article of Examples 21 to 23 having a film thickness of the outermost layer of 3 to 20 nm has a film refractive index after OC of 1.428 or less, The initial contact angle of the outermost layer was 80 ° or more. Further, ΔTmax after OC was 2.0% or more, ΔTmax change amount before and after OC was small, and even when the outermost layer was formed, the antireflection performance of the silica-based porous film was almost maintained.
On the other hand, in the article of Example 20 in which the film thickness of the outermost layer was 0.2 nm, the initial contact angle of the outermost layer was less than 80 °.
In the articles of Examples 24 and 25 in which the film thicknesses of the outermost layer were 25.3 nm and 44.1 nm, the film refractive index after OC exceeded 1.428. Further, the ΔTmax change amount before and after the OC was large.

From the above results, a refractive index at a wavelength of 550 nm is 1 for a multilayer film comprising a silica-based porous film satisfying the following condition (I) and the outermost layer satisfying the following conditions (II) and (III). .428 or less, the initial water contact angle of the outermost layer is 80 ° or more, and the water contact angle after exposing light having a wavelength of 300 to 800 nm at an irradiance of 650 W / m ² for 1000 hours is 76 ° or less. It was confirmed that.
(I) The number of open pores having a diameter of 20 nm or more opened on the surface on the outermost layer side of the silica-based porous membrane is 16 or less per 1000 nm × 1000 nm.
(II) The outermost layer is composed of a silicone polymer that satisfies the above conditions (1) and (2).
(III) The thickness of the outermost layer is 3 to 20 nm.

DESCRIPTION OF SYMBOLS 10 Article 12 Transparent base material 14 Silica-type porous film 16 Outermost layer 18 Multilayer film

Claims (10)

An article having a multilayer film composed of a silica-based porous film and an outermost layer provided in contact with the silica-based porous film on a transparent substrate,
The multilayer film has a refractive index of 1.428 or less at a wavelength of 550 nm,
The initial water contact angle of the outermost layer is 80 ° or more, and the water contact angle after exposing light having a wavelength of 300 to 800 nm at an irradiance of 650 W / m ² for 1000 hours is 76 ° or less. Goods to be.   2. The article according to claim 1, wherein the number of open pores having a diameter of 20 nm or more opened on the surface on the outermost layer side of the silica-based porous membrane is 16 or less per 1000 nm × 1000 nm. The outermost layer is composed of a silicone polymer;
The silicone polymer is a copolymer containing a compound (X) represented by the following general formula (x) and a compound (Y) represented by the following general formula (y),
The molar ratio (Y / (X + Y)) of the compound (Y) to the total amount of the compound (X) and the compound (Y) is 0.2 to 0.8,
The article according to claim 1 or 2, wherein the silicone polymer has a weight average molecular weight of 750 to 5,000.
Si (OR ¹ ) ₄ (x)
R ³ Si (OR ² ) ₃ (y)
[Wherein R ¹ is an alkyl group having 1 to 3 carbon atoms, and a plurality of R ¹ in the formula may be the same or different, and R ² is an alkyl group having 1 to 3 carbon atoms. And a plurality of R ² in the formula may be the same or different, and R ³ is a hydrocarbon group having 1 to 20 carbon atoms. ]   The article according to any one of claims 1 to 3, wherein the thickness of the outermost layer is 3 to 20 nm. An article having a multilayer film composed of a silica-based porous film and an outermost layer provided in contact with the silica-based porous film on a transparent substrate,
The number of open pores having a diameter of 20 nm or more opened on the surface on the outermost layer side of the silica-based porous membrane is 16 or less per 1000 nm × 1000 nm,
The outermost layer is composed of a silicone polymer;
The silicone polymer is a copolymer containing a compound (X) represented by the following general formula (x) and a compound (Y) represented by the following general formula (y),
The molar ratio (Y / (X + Y)) of the compound (Y) to the total amount of the compound (X) and the compound (Y) is 0.2 to 0.8,
The weight average molecular weight of the silicone polymer is 750 to 5000,
An article having a thickness of the outermost layer of 3 to 20 nm.
Si (OR ¹ ) ₄ (x)
R ³ Si (OR ² ) ₃ (y)
[Wherein R ¹ is an alkyl group having 1 to 3 carbon atoms, and a plurality of R ¹ in the formula may be the same or different, and R ² is an alkyl group having 1 to 3 carbon atoms. And a plurality of R ² in the formula may be the same or different, and R ³ is a hydrocarbon group having 1 to 20 carbon atoms. ]   The article according to claim 5, wherein the multilayer film has a refractive index of 1.428 or less at a wavelength of 550 nm. A method for producing an article having a multilayer film comprising a silica-based porous film and an outermost layer provided in contact with the silica-based porous film on a transparent substrate,
Forming a silica-based porous film on a transparent substrate;
Applying an overcoat liquid to the surface of the silica-based porous membrane and drying to form an outermost layer,
The overcoat liquid contains a silicone polymer and a solvent,
The silicone polymer is a copolymer containing a compound (X) represented by the following general formula (x) and a compound (Y) represented by the following general formula (y),
The molar ratio (Y / (X + Y)) of the compound (Y) to the total amount of the compound (X) and the compound (Y) is 0.2 to 0.8,
A method for producing an article, wherein the silicone polymer has a weight average molecular weight of 750 to 5,000.
Si (OR ¹ ) ₄ (x)
R ³ Si (OR ² ) ₃ (y)
[Wherein R ¹ is an alkyl group having 1 to 3 carbon atoms, and a plurality of R ¹ in the formula may be the same or different, and R ² is an alkyl group having 1 to 3 carbon atoms. And a plurality of R ² in the formula may be the same or different, and R ³ is a hydrocarbon group having 1 to 20 carbon atoms. ]   The method for producing an article according to claim 7, wherein the number of open pores having a diameter of 20 nm or more opened on the surface on the outermost layer side of the silica-based porous membrane is 16 or less per 1000 nm x 1000 nm.   The method for producing an article according to claim 7 or 8, wherein the outermost layer has a thickness of 3 to 20 nm.   The method for producing an article according to any one of claims 7 to 9, wherein the multilayer film has a refractive index of 1.428 or less at a wavelength of 550 nm.

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