JP2012030592A - Laminate having porous silica film, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate having a porous silica film in which the adhesion of a base material with a porous silica film is high and the visible light transmittance is high.SOLUTION: The laminate includes a porous silica film having the refractive index of 1.20-1.35 on a translucent base material having Tg of ≤200°C, wherein the variation of the visible light transmittance of the laminate is less than 5% to the visible light transmittance of the laminate before a test in the abrasion resistant test in which the cheesecloth described in Military Standard MIL-CCC-c-440 is made to reciprocate for 20 times by the load of 500 g/cmon the surface of the porous silica film.

Description

  The present invention relates to a laminate having a porous silica membrane and a method for producing the same.

Patent Documents 1 to 5 are known as porous silica films for antireflection applications.
In Patent Documents 1 and 2, a porous silica film is formed using an organic polymer as a template material. However, since the removal of the organic polymer is due to heating, the film shrinks and sufficient wear resistance cannot be obtained. .
In Patent Document 3, a substrate having a low Tg is not used.

In Patent Document 4, a porous silica layer using a beaded silica string is formed on a transparent thermoplastic substrate. This silica-containing laminate is considered to have a high film strength due to pencil hardness but low wear resistance.
Patent Document 5 obtains a low refractive index and wear resistance by applying a liquid containing silica particles having a particle diameter of 10 to 60 nm to glass and applying a temperature of 600 ° C. or higher. Since this method requires applying a temperature of 600 ° C. or higher, it cannot be used for a substrate having a low Tg.

  In Patent Document 1, a porous silica film is formed from a silica-based composition containing alkoxysilanes, an organic solvent, and water. Patent Document 1 also describes that an organic compound is used in combination, but here, the porous film by the template method using an organic polymer is distorted or crushed by removing the organic polymer. It is described that the film structure becomes unstable. For this reason, the molecular weight of the organic compound used is small, and no high molecular weight compound such as an organic polymer is used. As a result, it is difficult to maintain a high porosity of the resulting porous silica film, and there is a drawback that a porous silica film having a low refractive index cannot be produced stably.

JP 2005-15309 A JP 2010-65174 A JP 2006-36598 A Japanese Patent No. 4437783 JP-T-2004-511418

As a laminate having a porous silica film for antireflection use, a material having high adhesion between the substrate and the porous silica film and high visible light transmittance is required, but the conventional technology sufficiently satisfies both. There was nothing to do.
The subject of this invention is providing the laminated body which has the high adhesiveness of a base material and a porous silica film | membrane, and has a visible light transmittance | permeability and which has a porous silica film | membrane.

As a result of intensive studies by the present inventors, it has been found that a laminate having a specific wear resistance has high adhesion between the substrate and the porous silica film.
Moreover, it discovered that the visible light transmittance | permeability of a laminated body improved by laminating | stacking a porous silica film | membrane with a refractive index of 1.20-1.35 on the translucent base material whose Tg is 200 degrees C or less. .
Further, in the porous silica film forming step, the organic polymer is used as a template material, and the organic polymer is extracted to form the porous silica film of the present invention on a translucent substrate having a Tg of 200 ° C. or lower. Made possible.

That is, the first gist of the present invention is a laminate having a porous silica film having a refractive index of 1.20 to 1.35 on a translucent substrate having a Tg of 200 ° C. or less, In the abrasion resistance test in which the cheese cloth described in the specification MIL-CCC-c-440 is reciprocated 20 times on the surface of the porous silica film with a load of 500 g / cm ² , the amount of change in the visible light transmittance of the laminate is It exists in the laminated body characterized by being less than 5% with respect to the visible light transmittance | permeability of the said laminated body before a test (Claim 1).

  The second gist of the present invention is a method for producing a laminate having a porous silica film on a translucent substrate having a Tg of 200 ° C. or less, comprising an alkoxysilane compound, water, an organic solvent, and an organic polymer. A method for producing a laminate having a porous silica film is characterized by including a step of wet-coating a composition containing Tg on a light-transmitting substrate having a Tg of 200 ° C. or less and then extracting the organic polymer ( Claim 4).

  According to the present invention, it is possible to provide a laminate having high adhesion between the substrate and the porous silica film and high visible light transmittance. The high adhesion as described above can suppress not only high wear resistance but also local peeling of the porous silica film caused by an environmental resistance test, or cracking of the film due to an increase in film distortion. At the same time, as the peel strength is improved, dirt can be easily wiped off in the cleaning of the film, and the easy cleaning can be significantly improved.

  Moreover, the manufacturing method suitable for manufacture of the laminated body of this invention can be provided.

It is a schematic sectional drawing which shows an example of the optical use laminated body (solar cell use) of this invention.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented without departing from the gist of the present invention.
1. Porous silica membrane laminate The laminate of the present invention has a porous silica membrane on a translucent substrate.
[Abrasion resistance]
In the abrasion resistance test in which the cheese cloth described in MIL-Spec MIL-CCC-c-440 is reciprocated 20 times on the surface of the porous silica film with a load of 500 g / cm ² , the laminate of the present invention is visible light of the laminate. The amount of change in transmittance is less than 5% with respect to the visible light transmittance of the laminate before the test.

The laminate of the present invention has the above-mentioned specific wear resistance, so that the adhesion between the translucent substrate and the porous silica film is improved, and as a result, an easy adhesion layer and a hard coat layer are required. There is an advantage that it is easy to produce.
As the cheese cloth, an equivalent product to the cheese cloth described in Mil-Spec MIL-CCC-c-440 is used.

Visible light transmittance measurement is intended only for the part subjected to the abrasion resistance test.
Visible light transmittance refers to the transmittance of light having a wavelength of 380 nm to 780 nm. A spectrophotometer or a visible light transmittance meter can be used for the measurement.
The amount of change in the visible light transmittance of the laminate in the abrasion resistance test relative to the visible light transmittance of the laminate before the abrasion resistance test is preferably smaller, preferably 3% or less, usually 0% or more. is there.

[Translucent substrate]
A light-transmitting substrate having a Tg of 200 ° C. or lower is used as the substrate. In addition, a translucent base material means a base material with a high transmittance | permeability of the light of a predetermined wavelength, and this wavelength is suitably selected according to the use of a translucent base material. The translucent substrate may have scattering and haze as long as it does not affect the performance. The wavelength is not limited to the range of visible light, but high transmittance in the visible light region is preferable for use in optical devices such as lenses, displays, solar cells, solar thermal power generation, building materials, and interior and exterior of automobiles. . Usually, the total light transmittance is 60% or more.

  Examples of translucent substrate materials include polymethyl methacrylate, acrylic resins such as cross-linked acrylates, aromatic polycarbonate resins such as bisphenol A polycarbonate, polyester resins such as polyethylene terephthalate, and amorphous such as polycycloolefins. Examples thereof include polyolefin resins, epoxy resins, styrene resins such as polystyrene, synthetic resins such as polysulfone resins, imide resins, and fluorine resins. Among these, polyethylene terephthalate, polymethyl methacrylate (PMMA), polycarbonate, and tetrafluoroethylene-ethylene copolymer (ETFE) are preferable. These can be used alone or in any combination of two or more.

The dimensions of the substrate used in the present invention are arbitrary. However, when a plate-like substrate is used as the translucent substrate, the thickness of the substrate is preferably 0.01 mm or more, more preferably 0.05 mm or more, from the viewpoint of mechanical strength and gas barrier properties. 0.1 mm or more is more preferable. The thickness is preferably 80 mm or less, more preferably 50 mm or less, more preferably 30 mm or less, more preferably 10 mm or less, and particularly preferably 3 mm or less from the viewpoint of weight reduction and light transmittance. Furthermore, as a magnitude | size of a translucent base material, 0.1 m < ² > or more is preferable from a viewpoint of obtaining an optical effect, 0.5 m < ² > or more is more preferable, and 1 m < ² > or more is especially preferable. Although there is no restriction | limiting in particular in an upper limit, Usually, 100 m < ² > or less is preferable and 50 m < ² > or less is more preferable.

  Moreover, the center line average roughness of the coating surface of a translucent base material is also arbitrary. However, from the viewpoint of the film forming property of the porous silica film to be laminated, the center line average roughness is preferably 10 nm or less, more preferably 8 nm or less, still more preferably 5 nm or less, and particularly preferably 3 nm or less. The center line average roughness is measured by a general-purpose surface roughness meter (for example, Surfcom 570A manufactured by Tokyo Seimitsu Co., Ltd.) according to JIS-B0601: 1994.

[Porous silica membrane]
<Refractive index>
The refractive index of the porous silica film of the present invention is 1.20 or more and 1.35 or less. Among these, 1.28 or less is more preferable, and 1.25 or less is particularly preferable. Moreover, it is preferable that it is 1.23 or more. When the refractive index is too large, the visible light transmittance of the laminate is lowered, and a sufficient optical effect cannot be obtained. On the other hand, if the refractive index is too small, the visible light transmittance of the laminate is lowered, and the mechanical strength of the porous silica film (hereinafter sometimes referred to as “silica body”) may be lowered.

In many materials, the refractive index of a translucent substrate having a Tg of 200 ° C. or lower is about 1.5. In order to impart low reflectivity, the refractive index of the laminated film is 1.20 to 1.35. preferable.
The refractive index means a value at a wavelength of 400 nm to 700 nm measured by an optical technique such as a spectroscopic ellipsometer method, reflectance measurement, reflection spectroscopic spectrum measurement or prism coupler, and preferably measured by a spectroscopic ellipsometer. Say. When measuring with a spectroscopic ellipsometer, the refractive index can be estimated by fitting the measured value with a Cauchy model or a Tauc-Lorentz model.

<Composition>
The silica content in the porous silica film is not particularly limited as long as the effects of the present invention are not significantly impaired. For example, in the silicon oxide composition, the ratio of silicon to all positive elements including silicon is usually 50 mol%. As mentioned above, it means 70 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more. If the silicon content is too small, the surface roughness of the silica-based porous body may increase and the mechanical strength may also decrease. Moreover, the higher the content ratio of silicon, the more porous the silica film that has better surface smoothness. The upper limit is ideally 100 mol%.

<Porous structure>
The porous silica film of the present invention has a porous structure having pores in order to keep the refractive index low. The structure is not particularly limited, and the hole is usually a connecting hole in which tunnels or independent holes are connected, but the detailed structure of the hole is not particularly limited. However, as the structure of the holes, continuous holes are preferable, and such continuous holes can be confirmed by an electron microscope.

  In order to obtain a skeleton with high mechanical strength, it is better not to have a regular structure. Specifically, in an XRD pattern (X-ray diffraction pattern), a diffraction angle (2θ) = 0.5 ° to 10 °. It is preferable not to have a diffraction peak whose diffraction peak intensity (area) is twice the standard deviation (that is, 2σ) or more in the region of °. Here, the diffraction peak means a diffraction peak having a periodic structure size D calculated by the following definition of 10 cm or more. Σ represents a standard deviation.

  The periodic structure size D can be calculated based on the Scherrer equation shown in the following equation (i). In equation (i), the Scherrer constant K is 0.9, and the X-ray wavelength used for the measurement is λ. The Bragg angle θ and the measured half-value width βo are each calculated by a profile fitting method. The half width β derived from the sample is corrected and calculated using the following formula (ii). A regression curve of the measured half-value width calculated from the diffraction peak of standard Si is created, and the half-value width of the corresponding angle is set as a reading device-derived half-value width βi. The unit of D is Å (angstrom), and the units of β, βo, and βi are radians.

  The standard deviation σ is defined as follows.

In addition, the refractive index, dielectric constant, and density can be adjusted by adjusting the pore size and porosity. By adjusting them, it can be applied to various applications in addition to optical applications. Can do.
Although there is no restriction | limiting in particular in a void | hole size, an average void | hole size is 0.1-300 nm normally, and becomes a porous body excellent in mechanical strength. Preferably it is 0.5 to 200 nm, more preferably 0.8 to 100 nm, and most preferably 1 to 80 nm. If it is too small, water vapor enters the pores due to capillary force, which may change the refractive index or affect the optical characteristics. On the other hand, if it is too large, there is a risk that the surface is defective, the surface property is deteriorated, and haze such as scattering occurs.

The porosity is not particularly limited, but the average porosity is preferably 10 to 90%, the average porosity is more preferably 20 to 85%, and the average porosity is more preferably 30 to 80%. If it is too small, the refractive index will not be low, and sufficient optical properties may not be obtained. On the other hand, if it is too large, there is a risk that the surface is defective, the surface property is deteriorated, and haze such as scattering occurs.
<Thickness>
Although there is no restriction | limiting in particular in the thickness of the porous silica film | membrane of this invention, in order to use as an optical functional layer, 0.05-10 micrometers is preferable, 0.08-8 micrometers is more preferable, 0.1-5 micrometers is 0.1-5 micrometers. More preferably, 0.13 to 3 μm is most preferable. When the thickness is less than 0.05 μm, it may be necessary to improve the flatness of the substrate, and in particular, from the viewpoint of increasing the area of the substrate, the film forming process may be difficult. On the other hand, if it exceeds 10 μm, in the heating step, the progress of the sol-gel reaction at the silica-based precursor-substrate interface becomes heterogeneous, and there is a possibility that strain is likely to remain in the porous body.

<Shape>
The shape of the porous silica membrane of the present invention is not particularly limited, but is preferably a membrane. The thickness of the porous silica film can be the same as the above film thickness. Moreover, when using a porous silica film | membrane as an optical function layer, it is preferable to provide a porous silica film | membrane in the base material more than fixed size. That 0.0025M ² or more, more preferably 0.05 m ² or more, more preferably 0.1 m ² or more, 1 m ² or more is most preferred. If it is smaller than this size, there is a possibility that the optical characteristics do not sufficiently appear.

<Surface property>
The laminated body of this invention may provide another layer between a base material and a porous silica film according to a use, or may laminate | stack another layer on a porous silica film. In such a case, it is preferable to control the static contact angle on the surface of the porous silica film. Specifically, the static contact angle with respect to water after heat treatment for 1 hour is usually 25 ° or more, particularly 30 ° or more. In particular, it is preferably 33 ° or more, and usually 90 ° or less, particularly 87 ° or less, more preferably 85 ° or less, and particularly preferably 82 ° or less. If the static contact angle is too small, the hydrophilicity of the silica body becomes too high, moisture tends to be adsorbed on the surface, and adhesion to other layers may be reduced. On the other hand, when the static contact angle is too large, the surface of the silica body is in a hydrophobic state, and there is a possibility that the limitation of the layer to be laminated or the substrate becomes large.

  The static contact angle can be measured as follows. That is, the static contact angle of water droplets is measured in an atmosphere of normal temperature and normal humidity. For the static contact angle, a water droplet is dropped on the surface of the silica body, and the contact angle of the water droplet at that time is measured. The measurement is performed in an atmosphere of normal temperature and normal humidity, and a water droplet size of 2 μl is dropped, measurement is performed within 1 minute, this is repeated 5 times or more, and the average value is obtained as the static contact angle.

<Water resistance>
When the porous silica film of the present invention is used for optical applications, it is important to control the optical film thickness (product of refractive index and film thickness). Less change is preferred. Specifically, the change rate of the film thickness before and after the water immersion treatment is preferably 50% or less, more preferably 30% or less, still more preferably 20% or less, and particularly preferably 10% or less. If the rate of change is too large, performance may be reduced in the application of optical applications.

The film thickness may be measured by using a P-15 type contact surface roughness meter manufactured by KLA-Tencor, Inc., and the measurement conditions may be stylus force (contact pressure) 0.2 mg and scan speed 10 um / sec. It can also be evaluated by a spectroscopic ellipsometer, reflection spectroscopic method, and prism coupler.
The porous silica film preferably has few cracks after being immersed in water, and the cracks can be observed visually or with an optical microscope. Specifically, the crack size is preferably 100 μm or less, more preferably 10 μm or less, and even more preferably 1 μm or less. If it exceeds 100 μm, the adhesion to the substrate may be lowered and haze may be increased. Furthermore, it is preferable that the total area of the region where no crack exists within 1 mm × 1 mm is 50% or more, more preferably 70% or less, and still more preferably 85% or more with respect to the surface of the silica body. If it is less than 50%, the stability and appearance of the optical performance may be lowered as an optical application.

In the water immersion treatment, the porous silica film is immersed in water under conditions of normal temperature and normal humidity (temperature 18 ° C. to 28 ° C., humidity 20% to 80% RH), taken out after 24 hours, and dried. Drying is not performed by heating at 100 ° C. or higher, but by air drying. As an evaluation of moisture and heat resistance, there is “high temperature and high humidity treatment”. That is, after the refractive index n1 of the silica body of the present invention at a wavelength of 550 nm is measured in advance, the silica body is allowed to stand under conditions of a temperature of 85 ° C. and a humidity of 85% RH, or a temperature of 60 ° C. and a humidity of 90% RH. Take out after 500 hours. Thereafter, the refractive index n2 of the porous silica film at a wavelength of 550 nm is measured again. The absolute value Δn ′ = | n2-n1 | of the refractive index difference at this time is preferably 0.001 to 0.15, more preferably 0.003 to 0.12, and still more preferably 0.005 to 0.1. 0.008 to 0.08 is particularly preferable.

2. Method for Producing Porous Silica Membrane The composition used in the method for producing a porous silica membrane of the present invention includes an alkoxysilane compound, water, an organic solvent, and an organic polymer.
In particular, the composition includes two or more types of alkoxysilanes, hydrolysates and partial condensates thereof, water, an organic solvent, a templating agent, and a catalyst, and silicon atoms derived from all alkoxysilanes in the composition The ratio of water to mol (mol / mol) is preferably 10 or more and 50 or less. Details are described below.

2-1. Composition 2-1-1. Alkoxysilane Examples of the alkoxysilane used in the present invention include tetraalkoxysilane, monoalkyltrialkoxysilane, dialkyldialkoxysilane, trialkylalkoxysilane, hydrolysates and partial condensates (oligomers, etc.) thereof.

Two or more alkoxysilanes are preferably used in combination, and preferably contain a hydrolyzate and partial condensate of these alkoxysilanes.
[Tetraalkoxysilane]
There is no restriction | limiting in the kind of tetraalkoxysilane. Examples of suitable ones include tetramethoxysilane, tetraethoxysilane, tetra (n-propoxy) silane, tetraisopropoxysilane, tetra (n-butoxy) silane, tetra (t-butoxy) silane, tetra (n-pentoxy). ) Silane, tetra (isopentoxy) silane, and the like.

From the viewpoint of stability of the silica-based precursor in the rough drying step, tetramethoxysilane, tetraethoxysilane, and oligomers thereof are preferable, and tetraethoxysilane is more preferable.
However, since tetraalkoxysilane tends to undergo hydrolysis and partial condensation over time, even when only tetraalkoxysilane is prepared, the hydrolyzate and partial condensate of tetraalkoxysilane usually coexists with tetraalkoxysilane. There are many cases.

[Monoalkyltrialkoxysilane]
There is no restriction | limiting in the kind of monoalkyl trialkoxysilane. Examples of suitable ones include trimethoxysilane, triethoxysilane, tri-n-propoxysilane, triisopropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, methyltriisopropoxysilane Ethyltrimethoxysilane, ethyltriethoxysilane, ethyltri-n-propoxysilane, ethyltriisopropoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltri-n-propoxysilane, isopropyltri Methoxysilane, isopropyltriethoxysilane, isopropyltri-n-propoxysilane, fluorotrimethoxysilane, fluorotriethoxysilane, isopropyltri-n-propoxysilane, trif Oromethyltrimethoxysilane, pentafluoroethyltrimethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, (3,3,3-trifluoropropyl) triethoxysilane, heptadecatrifluorodecyltrimethoxy Silane, trifluoromethyltrimethoxysilane, pentafluorophenyltrimethoxysilane, pentafluorophenyltriethoxysilane, triethoxy-1H, 1H, 2H, 2H-tridecafluoro-n-octylsilane, phenyltrimethoxysilane, phenyltriethoxy Silane, phenyltri-n-propoxysilane, phenyltriisopropoxysilane.
In addition, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, in which an alkyl group substituted on a silicon atom has a reactive functional group, 3 -Triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-carboxypropyltrimethoxysilane, 3-trihydroxysilyl -1-Pro Down - some, such as sulfonic acid.

[Dialkyl dialkoxysilane]
There is no restriction | limiting in the kind of dialkyl dialkoxysilane. Examples of suitable ones are methyldimethoxysilane, methyldiethoxysilane, methyldi-n-propoxysilane, methyldiisopropoxysilane, ethyldimethoxysilane, ethyldiethoxysilane, ethyldi-n-propoxysilane, ethyldiisopropoxy. Silane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-propoxysilane, dimethyldiisopropoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldi-n
-Propoxysilane, diethyldiisopropoxysilane, di-n-propyldimethoxysilane, di-n-propylethoxysilane, di-n-propyldi-n-propoxysilane, di-n-propyldiisopropoxysilane, diisopropyldimethoxysilane , Diisopropylethoxysilane, diisopropyldi-n-propoxysilane, diisopropyldiisopropoxysilane, di-n-butyldimethoxysilane, di-n-butylethoxysilane, di-n-butyldi-n-propoxysilane, di-n- Butyldiisopropoxysilane, di-sec-butyldimethoxysilane, di-sec-butylethoxysilane, di-sec-butyldi-sec-propoxysilane, di-sec-butyldiisopropoxysilane, di-tert-butyldimeth Sisilane, di-tert-butylethoxysilane, di-tert-butyldi-n-propoxysilane, di-tert-butyldiisopropoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldi-n-propoxysilane, diphenyldi Isopropoxysilane and the like. Further, there are N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane and the like in which an alkyl group substituted on a silicon atom has a reactive functional group.

[Trialkylalkoxysilane]
There is no limitation on the type of trialkylalkoxysilane. Examples of suitable ones include trimethylmethoxysilane, trimethylethoxysilane, triethylethoxysilane, tri-n-propylmethoxysilane, tri-n-propylethoxysilane and the like.
[Other alkoxysilanes]
Other alkoxysilanes include bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane, 1,2-bis (trimethoxysilyl) ethane, 1,2-bis (triethoxysilyl) ethane, 1, An organic residue such as 4-bis (trimethoxysilyl) benzene, 1,4-bis (triethoxysilyl) benzene, 1,3,5-tris (trimethoxysilyl) benzene has two or more trialkoxysilyl groups. There is a combination.

Among alkoxysilanes, tetraalkoxysilane, monoalkyltrialkoxysilane, and dialkyldialkoxysilane are preferable, and tetraalkoxysilane is more preferable in order to strengthen the skeleton of the porous structure.
Furthermore, from the viewpoint of environmental resistance of the porous membrane, monoalkyltrialkoxysilanes and dialkyldialkoxysilanes having an aromatic hydrocarbon group or an aliphatic hydrocarbon group are preferred. Specifically, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethylsilane and the like are preferable.

[Preferred combinations]
When two or more alkoxysilanes are used in combination, tetraalkoxysilane, monoalkyltrialkoxysilane, and monoalkyltrialkoxysilane are preferable from the viewpoint of controlling the sol-gel reaction.
From the viewpoint of wettability to the substrate, tetraalkoxysilane and dialkyl dialkoxysilane, monoalkyltrialkoxysilane and dialkyl dialkoxysilane are preferable.

From the viewpoint of improving the smoothness of the film, it is preferable to use three or more types of alkoxysilanes.
[Ratio of alkoxysilane]
When using together 2 or more types of alkoxysilane, the compounding ratio will not have a restriction | limiting in particular unless the effect of this invention is impaired remarkably. When two types of alkoxysilanes are used in combination, for example, from the viewpoint of water resistance of the formed silica body, 2: 8 to 5: 5 is preferable in terms of silicon atoms of alkoxysilane, and 3: 7 to 5: 5 is preferable. More preferably, 4: 6 to 5: 5 is most preferable.

Further, from the viewpoint of strengthening the skeleton of the porous structure, it is effective to contain tetraalkoxysilane, and the ratio of silicon atoms derived from tetraalkoxysilane to silicon atoms of all alkoxysilanes is usually 0.15 (mol / mol) or more, preferably 0.3 (mol / mol) or more, more preferably 0.35 (mol / mol) or more, and usually 0.9 (mol / mol) or less, preferably 0.8 (mol / mol). mol / mol) or less, more preferably 0.7 (mol / mol) or less.

  Here, the silicon atoms of all alkoxysilanes refer to the total number of silicon atoms possessed by all alkoxysilanes contained in the composition. Therefore, even if the composition contains a compound having a silicon atom in addition to alkoxysilane, the silicon atom contained in the compound is not involved in the calculation of the ratio. In addition, the ratio of the silicon atom of the alkoxysilane can be measured by Si-NMR.

  In the composition, the compound containing silicon (silicon atom-containing compound) is usually 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and further preferably 1% by weight. % Or more, and usually 50% by weight or less, preferably 30% by weight or less, more preferably 20% by weight or less, and still more preferably 15% by weight or less. If it is less than 0.01% by weight, the surface properties of the porous body may be deteriorated in the heating step, resulting in a poor appearance. On the other hand, if it exceeds 50% by weight, it tends to be affected by the planarity of the substrate, and the sol-gel reaction in the film forming process may become non-uniform in the surface direction.

Further, from the viewpoint of controlling the film thickness of the resulting porous silica film, the solid content concentration including the silicon atom-containing compound and the template material described below is usually 0.02% by weight or more, preferably 0.5%. % By weight or more, more preferably 1% by weight or more. Further, it is usually preferably 50% by weight or less, more preferably 40% by weight or less, and further preferably 35% by weight or less.
2-1-2. Water The composition used in the present invention contains water. Although water is essential in the sol-gel reaction, in the present invention, it plays an important role in controlling the surface tension of the composition and forming a high-quality silica-based precursor in the film forming process. Although there is no restriction | limiting in particular in the purity of the water to be used, Usually, the water which performed any one or both processing among ion exchange and distillation should just be used. However, when the obtained silica body is used in an application field that particularly dislikes minute impurities such as a laminated body for optical applications, a porous silica film with higher purity is desirable. It is preferable to use pure water. Further, among impurities, contamination of 100 nm or more may affect the progress of the sol-gel reaction in the silica-based composition. For example, water passed through a filter having a pore size of 0.01 μm to 0.5 μm may be used.

  As the amount of water used, the ratio of water to silicon atoms in all alkoxysilanes is usually 10 (mol / mol) or more, preferably 11 (mol / mol) or more, more preferably 12 (mol / mol) or more. Moreover, it shall be 30 (mol / mol) or less and 20 (mol / mol) or less. If the ratio of water to silicon atoms in the total alkoxysilane is smaller than the above range, it is difficult to control the sol-gel reaction, the pot life is short, a film is formed in a non-homogeneous state, the surface is rough, and the Abrasion may be inferior. On the other hand, if it is larger than the above range, the sol-gel reaction becomes difficult to proceed, and the reaction takes time, so that the water resistance may be lowered. The amount of water can be calculated by the Karl Fischer method (coulometric titration method).

2-1-3. Organic solvent The composition used in the present invention contains an organic solvent. Alcohols are most suitable as the solvent. Alcohols have an affinity for the alkoxysilane, its hydrolyzate, and further a partial condensate, and therefore are preferable for causing the sol-gel reaction during the formation of the porous body to proceed homogeneously. Furthermore, a high-quality silica-based precursor can be obtained by maintaining a stable state at the gas-liquid (composition) interface and the solid (base material) -liquid (composition) interface generated in the film forming process.

  There is no restriction on the type of alcohol. Examples of suitable ones include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl -1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2,2-dimethyl-1-propanol, 1-hexanol, 2-hexanol, 3-hexanol , Monohydric alcohols such as ethylene glycol monomethyl ether, 2-ethoxyethanol, propylene glycol monomethyl ether, dihydric alcohols such as ethylene glycol and diethylene glycol, trihydric alcohols such as glycerin, alicyclic alcohols such as cyclohexanol, benzyl alcohol Which aromatic alcohols, and the like. In addition, these 1 type may be used independently and 2 or more types may be used together by arbitrary combinations and a ratio.

Among these, monohydric alcohols and dihydric alcohols are preferable from the viewpoint of the hydrolysis reaction of the alkoxysilane contained, and monohydric alcohols are more preferable.
Further, from the viewpoint of the surface properties of the resulting silica body, methanol, ethanol, 1-propanol, t-butanol, 2-propanol, 2-methyl-1-propanol, 1-butanol, 1-pentanol, ethyl acetate, acetic acid Methyl, isobutyl acetate and the like are preferable. Therefore, it is preferable to use at least two selected from these.

In addition, the boiling point is preferably 110 ° C. or lower, more preferably 100 ° C. or lower, and even more preferably 90 ° C. or lower from the viewpoint of facilitating the formation of the structure of the silica-based precursor in the film forming step and improving wettability with the substrate. For example, methanol, ethanol, 1-propanol, t-butanol, 2-propanol and the like are preferable.
On the other hand, from the viewpoint of suppressing deformation of the porous structure in the heating step, the boiling point is preferably 100 ° C or higher, more preferably 110 ° C or higher, and more preferably 120 ° C or higher. For example, 2-methyl-1-propanol, 1-butanol, and 1-pentanol are preferable.

  Further, alcohols having different boiling points may be mixed. In this case, in order to suppress azeotropy in each step, the difference in boiling points of the combined alcohols is preferably 5 ° C. or more, preferably 10 ° C. or more. More preferably, 20 degreeC or more is further more preferable. Further, the ratio of alcohols on the high boiling point side to the total alcohols is usually 5% by weight or more, preferably 10% by weight or more, more preferably 40% by weight or more, further preferably 60% by weight or more, particularly preferably. 80% by weight or more. In addition, the upper limit of the said ratio is 98 weight% normally. If the upper limit is exceeded, the surface properties of the resulting porous silica film may be lowered, and if it is less than the lower limit, there is a risk that sufficient effects cannot be obtained.

The silica-based composition used in the present invention may contain an organic solvent other than the above alcohols. In order to further improve the wettability with the substrate and the film-forming property in the film-forming process, an organic solvent other than alcohols can be used.
Examples of suitable organic solvents include: ethers or esters such as methyl acetate, ethyl acetate, isobutyl acetate, ethylene glycol dimethyl ether, propylene glycol methyl ether acetate; ketones such as acetone and methyl ethyl ketone; formamide, N-methylformamide N-ethylformamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylacetamide, N-ethylacetamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone, N -Formylmorpholine, N-acetylmorpholine, N-formylpiperidine, N-acetylpiperidine, N-formylpyrrolidine, N-acetylpyrrolidine, N, N'-diformylpiperazine, N, Amides such as N′-diformylpiperazine and N, N′-diacetylpiperazine; Lactones such as γ-butyrolactone; Ureas such as tetramethylurea and N, N′-dimethylimidazolidine; Dimethylsulfoxide and the like .

  Moreover, the usage-amount of the whole organic solvent is arbitrary unless the effect of this invention is impaired remarkably. However, it is usually 0.05% by weight or more, particularly 0.1% by weight or more, preferably 1% by weight or more, and more preferably 10% by weight or more. Further, it is usually 50% by weight or less, particularly 40% by weight or less, and more preferably 30% by weight or less. If the amount of the organic solvent used is too small or too large, there is a possibility that a sufficient effect cannot be obtained.

2-1-4. Organic Polymer The composition used in the production method of the present invention contains an organic polymer as a template material. After applying a composition containing an organic polymer to a substrate to form a silica-based precursor, a silica film having a porous structure is obtained by removing all or part of the organic polymer in an extraction step.
From the viewpoint of forming a porous structure, the weight average molecular weight of the organic polymer is usually 500 or more, preferably 1,000 or more, more preferably 2,000 or more, and particularly preferably 5,000 or more. If the weight average molecular weight is too small, it may be difficult to maintain the porosity of the porous silica film high, and the low refractive index nanoporous silica film may not be stably produced. On the other hand, although there is no restriction | limiting in the upper limit of a weight average molecular weight, Usually, it is 100,000 or less, Preferably it is 70,000 or less, More preferably, it is 40,000 or less. If the weight average molecular weight is too large, the composition thickens and the film-forming property may be lowered.

The type of the organic polymer is not particularly limited as long as the effects of the present invention are not significantly impaired. For example, (meth) acrylate polymer, polyanhydride polymer, polyether polymer, polycarbonate polymer, polyester polymer Examples thereof include organic polymers such as molecules.
The (meth) acrylate polymer is composed of acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, and derivatives thereof. Specific examples include diethylene glycol acrylate, dipropylene glycol acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, acrylamide, vinyl pyridine, N-methyl acrylamide, N, N-dimethyl acrylamide, diethylene glycol methacrylate, dipropylene glycol methacrylate, methoxy. Diethylene glycol methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, methacrylamide, N-methylmethacrylamide, N, N-dimethylmethacrylamide, methyl acrylate, ethyl acrylate, isopropyl acrylate, amyl acrylate, 2-methoxypropyl acrylate, 2-Ethoxypropyl acrylate , 2-ethylhexyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, amyl methacrylate, 2-methoxypropyl methacrylate, 2-ethoxyethyl methacrylate, 2-ethylhexyl methacrylate, benzyl methacrylate, and the like. These may be used alone or in combination of two or more.

  The polyanhydride polymer is obtained from an aliphatic dicarboxylic acid having 2 or more carbon atoms. Specific examples thereof include polymalonic anhydride, polysuccinic anhydride, polyoxalic anhydride, polyglutaric anhydride, and the like, methyl esters, ethyl esters, and propyl esters thereof. These may be used alone or in combination of two or more.

The polyether polymer is composed of a polyalkylene glycol compound having 2 or more carbon atoms. Specific examples include polyethylene glycol, polypropylene glycol, polytrimethylene glycol, polytetramethylene glycol, polypentamethylene glycol, polyethylene glycol-polypropylene glycol block copolymer, polyethylene glycol-polytetramethylene glycol block copolymer, polyethylene glycol- Polypropylene glycol-polyethylene glycol block copolymer, etc., methyl ether, ethyl ether thereof; polyethylene glycol mono-p-methylphenyl ether, polyethylene glycol mono-p-ethylphenyl ether, polyethylene glycol mono-p-propylphenyl ether, them Methyl ether, ethyl ether; polyethylene glycol monopentanoic acid Ester, polyethylene glycol mono-hexanoic acid ester, polyethylene glycol mono-heptanoic acid esters, their methyl ether, ethyl ether, and the like. These may be used alone or in combination of two or more.

The polycarbonate polymer is an aliphatic polycarbonate having 2 or more carbon atoms, and specific examples thereof include polyethylene carbonate, polypropylene carbonate, polytrimethylene carbonate, polypentamethylene carbonate, their methyl ether, and ethyl ether. These may be used alone or in combination of two or more.
The polyester polymer is composed of a compound comprising an aliphatic chain having 2 or more carbon atoms and an ester bond. Specific examples include polyethylene oxalate, polyethylene malonate, polyethylene succinate, polyethylene glutarate, polypropylene oxalate, polypropylene malonate, polypropylene succinate, polypropylene glutarate, their methyl ether, ethyl ether, propyl ether and the like. Can be mentioned. These may be used alone or in combination of two or more.

  From the viewpoint of the pot life of the silica body and the stability of the silica body in the film forming step, (meth) acrylic polymers and polyether polymers are preferred, and polyether polymers are more preferred. Among these, from the viewpoint of affinity with the hydrolyzable group-containing silane, the alkylene glycol compound of the repeating unit constituting the polyether polymer preferably has 2 to 4 carbon atoms, and more preferably 2 or 3.

  Furthermore, in order to stably maintain the structure of the silica-based precursor from the film forming step to the heating step, a copolymer obtained by combining alkylene glycol compounds having different carbon numbers is preferable. At this time, the content of the alkylene glycol compound having a short carbon number, that is, having a high affinity with the silanol group of the hydrolyzable group-containing silane is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 20% by weight or more. , Preferably 23% by weight or more, more preferably 25% by weight or more, and usually 100% by weight or less, preferably 90% by weight or less, more preferably 85% by weight or less. By being within the above range, the template material can exist more stably with respect to the hydrolyzate or condensate of the hydrolyzable group-containing silane formed during the sol-gel reaction of the hydrolyzable group-containing silane. .

  The organic polymer contained in the composition is preferably 0.1% by weight or more, more preferably 1% by weight or more, further preferably 1.2% by weight or more, and 1.4% by weight or more. Particularly preferred. This can stabilize and produce the sol-gel reaction of the hydrolyzable group-containing silane in the film forming process. Although there is no restriction | limiting in an upper limit, 50 weight% or less is preferable, 40 weight% or less is more preferable, and 30 weight% or less is especially preferable. If the upper limit is exceeded, the composition may thicken and the film-forming property may decrease.

2-1-5. Surfactant The composition used in the present invention may contain a surfactant as long as the effects of the present invention are not significantly impaired. Any known surfactant can be used. In particular, in increasing the area of the base material, the film forming property may be remarkably improved by adding. There is no restriction | limiting in particular in the kind, combination, and ratio, You may use the following 2 or more types of surfactant. Specific examples include nonionic surfactants such as polyethylene glycol, polypropylene glycol, and polyisobutylene glycol, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorine whose lipophilic group is a fluorocarbon group. It is preferable to select two or more types of surfactants, silicone surfactants whose oleophilic groups are siloxane chains, surfactants whose oleophilic groups are alkyl groups, etc. Among them, nonionic surfactants and fluorine-based surfactants are preferred. It is preferably selected from combinations of surfactants (particularly those containing perfluoroalkyl groups) and combinations of nonionic surfactants and silicone surfactants (particularly those containing siloxane bonds). The hydrophilic group of these surfactants is preferably, for example, a hydroxyl group, a carbonyl group, a carboxyl group or the like. Polyether, polyglycerin and the like are also preferable.

Examples of the fluorosurfactant include hexaethylene glycol (1,1,2,2,3,3-hexafluoropentyl) ether, 1,1,2,2-tetrafluorooctyl (1,1,2,2). , -Tetrafluoropropyl) ether, sodium perfluorododecyl sulfonate, and the like.
Examples of the silicone surfactant include SH21 series and SH28 series (Toray Dow Corning Co., Ltd.).

  Further, the ratio of the surfactant to the silicon atoms of the total hydrolyzable group-containing silane is usually 0.001 (mol / mol) or more, preferably 0.002 (mol / mol) from the viewpoint of the surface properties of the resulting silica body. ) Or more, more preferably 0.003 (mol / mol) or more, and usually 0.05 (mol / mol) or less, preferably 0.04 (mol / mol) or less, more preferably 0.03 (mol / mol). mol) or less.

2-1-6. The catalyst composition may contain a catalyst. For example, a substance that promotes the hydrolysis and dehydration condensation reaction of the alkoxysilane described above can be arbitrarily used.
Examples include hydrofluoric acid, phosphoric acid, boric acid, hydrochloric acid, nitric acid, sulfuric acid, formic acid, acetic acid, oxalic acid, maleic acid, methylmalonic acid, stearic acid, linolenic acid, benzoic acid, phthalic acid, citric acid, succinic acid. Acids such as acids; Amines such as ammonia, butylamine, dibutylamine and triethylamine; Bases such as pyridine; Lewis acids such as acetylacetone complex of aluminum;

Moreover, a metal chelate compound is also mentioned as an example of a catalyst. Examples of the metal species of the metal chelate compound include titanium, aluminum, zirconium, tin, and antimony. Specific examples of the metal chelate compound include the following.
Examples of the aluminum complex include di-ethoxy mono (acetylacetonato) aluminum, di-n-propoxy mono (acetylacetonato) aluminum, di-isopropoxy mono (acetylacetonato) aluminum, di-n- Butoxy mono (acetylacetonato) aluminum, di-sec-butoxy mono (acetylacetonato) aluminum, di-tert-butoxy mono (acetylacetonato) aluminum, monoethoxy bis (acetylacetonato) aluminum, mono -N-propoxy bis (acetylacetonato) aluminum, monoisopropoxy bis (acetylacetonato) aluminum, mono-n-butoxy bis (acetylacetonato) aluminum, mono-sec-but Si-bis (acetylacetonato) aluminum, mono-tert-butoxy bis (acetylacetonato) aluminum, tris (acetylacetonato) aluminum, diethoxy mono (ethylacetoacetate) aluminum, di-n-propoxy mono ( Ethyl acetoacetate) aluminum, diisopropoxy mono (ethyl acetoacetate) aluminum, di-n-butoxy mono (ethyl acetoacetate) aluminum, di-sec-butoxy mono (ethyl acetoacetate) aluminum, di-tert- Butoxy mono (ethyl acetoacetate) aluminum, monoethoxy bis (ethyl acetoacetate) aluminum, mono-n-propoxy bis (ethyl acetoacetate) aluminum, mono Sopropoxy bis (ethyl acetoacetate) aluminum, mono-n-butoxy bis (ethyl acetoacetate) aluminum, mono-sec-butoxy bis (ethyl acetoacetate) aluminum, mono-tert-butoxy bis (ethyl acetoacetate) Examples thereof include aluminum chelate compounds such as aluminum and tris (ethylacetoacetate) aluminum.

  Titanium complexes include triethoxy mono (acetylacetonato) titanium, tri-n-propoxy mono (acetylacetonato) titanium, triisopropoxy mono (acetylacetonato) titanium, tri-n-butoxy mono (acetyl). Acetonato) titanium, tri-sec-butoxy mono (acetylacetonato) titanium, tri-tert-butoxy mono (acetylacetonato) titanium, diethoxy bis (acetylacetonato) titanium, di-n-propoxy bis (Acetylacetonato) titanium, diisopropoxy bis (acetylacetonato) titanium, di-n-butoxy bis (acetylacetonato) titanium, di-sec-butoxy bis (acetylacetonato) titanium, di-tert -Butoxy bis (ace Ruacetonate) titanium, monoethoxy tris (acetylacetonato) titanium, mono-n-propoxy tris (acetylacetonato) titanium, monoisopropoxy tris (acetylacetonato) titanium, mono-n-butoxy tris (acetyl) Acetonato) titanium, mono-sec-butoxy-tris (acetylacetonato) titanium, mono-tert-butoxy-tris (acetylacetonato) titanium, tetrakis (acetylacetonato) titanium, triethoxy mono (ethylacetoacetate) titanium , Tri-n-propoxy mono (ethyl acetoacetate) titanium, triisopropoxy mono (ethyl acetoacetate) titanium, tri-n-butoxy mono (ethyl acetoacetate) titanium, tri-sec-butyl Xy mono (ethyl acetoacetate) titanium, tri-tert-butoxy mono (ethyl acetoacetate) titanium, diethoxy bis (ethyl acetoacetate) titanium, di-n-propoxy bis (ethyl acetoacetate) titanium, diiso Propoxy bis (ethyl acetoacetate) titanium, di-n-butoxy bis (ethyl acetoacetate) titanium, di-sec-butoxy bis (ethyl acetoacetate) titanium, di-tert-butoxy bis (ethyl acetoacetate) Titanium, monoethoxy tris (ethyl acetoacetate) titanium, mono-n-propoxy tris (ethyl acetoacetate) titanium, monoisopropoxy tris (ethyl acetoacetate) titanium, mono-n-butoxy tris (ethyl acetoacetate) Acetate) titanium, mono-sec-butoxy tris (ethyl acetoacetate) titanium, mono-tert-butoxy tris (ethyl acetoacetate) titanium, tetrakis (ethyl acetoacetate) titanium, mono (acetylacetonate) tris (ethyl aceto) Acetate) titanium, bis (acetylacetonato) bis (ethylacetoacetate) titanium, tris (acetylacetonato) mono (ethylacetoacetate) titanium and the like.

Among those described above, acids or metal chelate compounds are preferable and acids are more preferable in order to more easily control the hydrolysis and dehydration condensation reaction of the alkoxysilane compound.
In addition, a catalyst may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

The amount of the catalyst used is arbitrary as long as the effects of the present invention are not significantly impaired. However, it is usually 0.001 mol times or more, preferably 0.003 mol times or more, particularly preferably 0.005 mol times or more, and usually 0.8 mol times or less, especially 0.5 mol to the alkoxysilane.
It is preferably 1 times or less, particularly preferably 0.1 mol times or less. If the amount of the catalyst used is too small, the hydrolysis reaction does not proceed properly, and active groups such as silanol groups are likely to remain in the silica body after production, which may reduce the water resistance of the silica body and is too high. It becomes difficult to control the reaction, and the surface concentration of the silica body may be lowered by further increasing the catalyst concentration during the production.

Moreover, it is preferable that pH of a composition is 6 or less from a film-forming viewpoint. More preferably, it is 5 or less, More preferably, it is 3 or less, Most preferably, it is 2 or less. By making it in this range, the surface modification of the substrate can be performed simultaneously during production, and the film-forming property tends to be improved.
2-1-7. Others The composition used in the present invention may contain components other than the alkoxysilane compound, water, organic solvent, catalyst, and template material described above. Moreover, the said component may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

2-2. Preparation of composition A composition is prepared by mixing the components constituting the composition described above. At this time, there is no limitation on the order of mixing the components. In addition, each component may be mixed all at once, or may be mixed continuously or intermittently in two or more times.
However, in order to control the sol-gel reaction which has heretofore been difficult to control and to prepare the composition more industrially, it is preferable to mix in the following manner. That is, alkoxysilane, water, and a solvent are mixed, and the mixture is subjected to a certain sol-gel reaction (aging), whereby alkoxysilane is hydrolyzed and dehydrated and polycondensed to some extent. Then, a mold material is mixed with the mixture to prepare a composition. Thus, the affinity between the alkoxysilane and the template material can be maintained under the sol-gel reaction conditions. The aging may be performed after the mixture and the mold material are mixed.

  During the aging, heating is preferably performed in order to promote hydrolysis / dehydration polycondensation reaction of alkoxysilane. The heating condition is not particularly limited as long as it does not exceed the boiling point of the solvent to be used, but is usually 30 ° C. or higher, more preferably 40 ° C. or higher, 50 ° C. or higher, and most preferably 55 ° C. or higher. If the heating temperature is too low, the reaction time becomes long, and a sufficient sol-gel reaction does not proceed, and there is a possibility that the affinity between the alkoxysilane and the template material cannot be obtained. On the other hand, the upper limit of the heating temperature is preferably 90 ° C. or less, and more preferably 80 ° C. or less. When the temperature exceeds 90 ° C., the molecular motion of the template material in the composition becomes intense, and as described above, the affinity between the alkoxysilane and the template material may not be controlled.

  The aging time with heating is not limited, but is usually 10 minutes or more, preferably 20 minutes or more, more preferably 30 minutes or more, more preferably 60 minutes or more, and usually 20 hours or less, preferably 15 hours or less. More preferably, it is 8 hours or less, More preferably, it is 4 hours or less. If the aging time is too short, it may be difficult to proceed the reaction uniformly. If the aging time is too long, it is necessary to lower the aging temperature, and the sol-gel reaction does not proceed sufficiently. May not be possible.

Furthermore, although there is no restriction | limiting in the pressure conditions at the time of ripening, Usually, it is preferable to age | cure | ripen by a normal pressure. When the pressure changes, the boiling point of the solvent also changes, and the solvent during aging volatilizes (evaporates), so that the composition ratio may change and the stability of the silica-based composition may be lowered.
Further, it is preferable that the composition used after the aging and before the coating step is further mixed with an organic solvent and diluted. Thereby, the sol-gel reaction rate in a composition can be reduced, and it becomes possible to maintain the pot life of a composition long. Further, from the viewpoint of yield in the production of the porous silica film, it is preferable to perform aging without heating. Aging without heating may be performed after the preparation of the composition.
From the viewpoint of the pot life of the composition, a neutralization step or a catalyst removal step may be performed.

2-3. Method for Producing Laminate Having Porous Silica Membrane In the method for producing a porous silica membrane of the present invention, a composition containing alkoxysilane, water, an organic solvent, and an organic polymer is applied onto a translucent substrate having a Tg of 200 ° C. or lower. A laminate having a porous silica film is obtained through an organic polymer extraction step.
In the present invention, since the composition is used and the extraction process is further performed, the refractive index is as low as 1.20 to 1.35 or less, and the porous structure has excellent adhesion to a light-transmitting substrate. A laminate having a porous silica film can be produced.

Hereinafter, the production method of the present invention will be described in detail.
2-3-1. Film-forming step In the method for producing a laminate having a porous silica film of the present invention, a silica-based precursor is produced by developing the composition described above on a translucent substrate having a Tg of 200 ° C. or lower.
[Film forming method]
In the present invention, the film forming method is not particularly limited. For example, spray coater, die coater, bar coater, table coater, applicator, doctor blade coater, dip coater, ink jet method, screen printing method, gravure printing method, flexographic printing. Law.

  In particular, in order to make the sol-gel reaction during film formation a silica-based precursor in a stable state regardless of the composition of the composition, the distance between the discharge part of the composition and the substrate is controlled, and It is preferred to cast the composition. By forming a film in a limited space formed from the discharge part and the base material, the sol-gel reaction can be advanced in a certain environment, and a homogeneous silica-based precursor can be formed. Specifically, the distance between the discharge part of the composition and the substrate is preferably 100 μm or less, more preferably 80 μm or less, further preferably 70 μm or less, and most preferably 50 μm or less. If it exceeds 100 μm, a difference in the progress of the sol-gel reaction occurs around the discharge part and around the substrate, and convection occurs in the film in a wet state, so that there is a tendency that a silica body cannot be obtained stably. On the other hand, the lower limit is preferably 0.1 μm or more, more preferably 0.3 μm or more, further preferably 0.5 μm or more, and most preferably 0.8 μm or more. If it is less than 0.1 μm, the share at the time of casting into the composition increases, and the sol-gel reaction may not proceed stably.

Furthermore, a die coater, a bar coater, a table coater, an applicator, a doctor blade coater, or the like is preferable, and a die coater is more preferable in order to realize highly reliable film thickness control as an optical functional layer in a wide range (large area).
When forming a film by the die coating method, a silica-based composition is supplied from a solution supply point at a constant flow rate and discharged from a die lip through a slit to form a silica-based precursor on the surface of the substrate. By conveying the material at a constant speed, the intended porous silica film can be formed.

Although there is no restriction | limiting in particular in the width | variety of a slit, Usually, 5 micrometers or more, Preferably it is 10 micrometers or more, More preferably, it is 20 micrometers or more, Usually, 100 micrometers or less, Preferably it is 80 micrometers or less, More preferably, it is 50 micrometers or less. If the lower limit is not reached, clogging may occur due to contamination, and if the upper limit is exceeded, a uniform film may not be formed.
The gap (distance) between the die lip (slit) and the substrate is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, more preferably 30 μm or more, and usually 100 μm. Hereinafter, a good quality silica-based precursor can be obtained by setting the thickness within the range of preferably 80 μm or less, more preferably 50 μm or less.

Although there is no restriction | limiting in particular in the discharge flow rate, Usually, 1-100 cc / min, Preferably it is 1-50.
cc / min, more preferably 1 to 20 cc / min, still more preferably 2 to 10 cc / min, most preferably 3 to 6 cc / min. If the value is below the lower limit value, the slit speed accuracy at the time of casting must be strict, so that it is difficult to increase the area of the substrate. On the other hand, if the upper limit is exceeded, convection will occur in the silica-based composition, and it may not be possible to form a stable wet film.

  Although there is no restriction | limiting in particular in a coating speed, Usually, 5-300 mm / second, Preferably it is 10-200 mm / second, More preferably, it is 20-100 mm / second, More preferably, it is 30-80 mm / second, Most preferably, 40- 60 mm / sec. If the lower limit is not reached, the casting conditions of the silica-based precursor in the film-forming process must be precisely controlled, which may impair productivity. If the upper limit is exceeded, the silica-based precursor is sheared in the film-forming process. There is a risk that stress is applied and the structure composed of the mold material and the silica component is destroyed.

  Although there is no restriction | limiting in particular in coating stop time, Usually, 0.1 to 3 second, Preferably it is 0.1 to 2 second, More preferably, it is 0.2 to 1 second, More preferably, it is 0.2 to 0.8 Seconds, most preferably 0.3 to 0.6 seconds. Below the lower limit, the interface state between the translucent substrate and the silica-based precursor is not stable, the adhesion with the translucent substrate is reduced, the leveling of the membrane surface does not progress, and the appearance of the membrane deteriorates. If the upper limit is exceeded, the sol-gel reaction at the interface between the substrate and the silica-based precursor will proceed excessively, and local defects may occur during casting.

  Although there is no restriction | limiting in particular in a coating distance, Usually, 0.05-500m, Preferably it is 0.1-300m, More preferably, it is 0.5-100m, More preferably, it is 0.8-50m, Most preferably 5 m. If the lower limit is not reached, there may be an unstable state in the initial stage of casting in the film forming process on the entire precursor, and if the upper limit is exceeded, a local non-uniform structure in the composition can be obtained. May affect surface properties.

The leveling accuracy of the die lip and the substrate support is usually ± 5 μm or less, preferably ± 2 μm or less, more preferably ± 1 μm or less, so that the coating can be performed with good reproducibility.
The shape of the die that can be used is not particularly limited as long as the solution can be uniformly distributed in the lateral direction. Examples include a T-die shape, a fishtail die shape, or a coat hanger die shape that is used during general film casting. Furthermore, it is desirable to have a die lip interval adjustment mechanism in order to make the distribution in the die lateral direction more uniform.

  Although there is no restriction | limiting in particular in the wet film thickness at the time of film forming, Usually, it is 0.1-100 micrometers, 0.5-80 micrometers is preferable, 1-55 micrometers is more preferable, 5-40 micrometers is more preferable, 10-25 micrometers Is most preferred. If this range is exceeded, it will be difficult to control the progress of the sol-gel reaction of the composition in the film-forming process, and the film will be easily affected by the wettability with the base material. The appearance may deteriorate.

For example, in the case of die coating, a mechanism in which the wet film thickness is controlled by the discharge liquid amount and the moving speed of the substrate is preferable, usually 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, and usually 60 μm or less, preferably Is 50 μm or less, more preferably 40 μm or less, a uniform porous silica film with little coating unevenness can be obtained.
<Environment of film forming process>
Although there is no restriction | limiting in particular in the relative humidity at the time of performing a film forming process, The more stable continuous coating is attained by controlling a relative humidity.

For example, the relative humidity is usually 20% RH or more, preferably 25% RH or more, more preferably 30% RH or more, more preferably 35% RH, and usually 85% RH or less, preferably 80% RH or less, more preferably It is preferable to form a silica precursor film in an environment of 75% or less RH.
Although there is no restriction | limiting in the temperature at the time of performing a film forming process, Usually 0 degreeC or more, Preferably it is 10 degreeC or more, More preferably, it is 15 degreeC or more, More preferably, it is 20 degreeC or more, Most preferably, it is 25 degreeC or more, Usually, 100 ° C or lower, preferably 80 ° C or lower, more preferably 70 ° C or lower, more preferably 60 ° C or lower, and most preferably 50 ° C or lower. If the temperature at the time of producing the silica-based precursor is too low, the progress of the sol-gel reaction may be slow and a homogeneous silica-based precursor may not be obtained, and if it is too high, the condensation reaction occurs rapidly. A large amount of unhydrolyzed alkoxysilane remains, which may affect the durability of the porous silica film.

Furthermore, the degree of cleanliness when performing the production process is not particularly limited, but from the viewpoint of suppressing the progress of the sol-gel reaction around the film defects and the nucleus around the contamination present on the substrate, The number of dust having a dust diameter of 0.5 μm or more is preferably 3,000,000 or less, more preferably 50,000 or less, and even more preferably 5,000 or less.
Moreover, there is no restriction | limiting in the atmosphere in a manufacturing process. For example, a silica-based precursor may be formed in an air atmosphere, and for example, the silica-based precursor may be applied in an inert atmosphere such as argon.

<Pretreatment>
In the production method of the present invention, prior to coating the composition on the translucent substrate, from the viewpoint of the wettability of the composition and the adhesion of the silica-based precursor to be produced, the translucent substrate is applied. A surface treatment may be applied. Examples of such surface treatment of the translucent substrate include silane coupling treatment, corona treatment, UV ozone treatment, plasma treatment and the like. Moreover, only 1 type may be performed for a surface treatment and you may perform it combining 2 or more types arbitrarily. In addition, the silylating agent mentioned later can also be used as a silane coupling process.

Moreover, although a manufacturing process may be performed once, you may divide into two or more times. For example, a porous silica film having a laminated structure can be formed by performing the production process twice or more through a rough drying process described later. This is useful, for example, when it is desired to stack layers having different refractive indexes.
<Post-processing>
In the production method of the present invention, a rough drying step of roughly drying the silica-based precursor may be performed after the film forming step for the purpose of removing alcohols or catalyst in the silica-based precursor. By performing the rough drying process, the alcohol, water and catalyst in the silica-based precursor are removed, thereby forming a structure in a stable state of the template material and the silica component present in the precursor. The structure of the precursor can be stabilized.

The method of rough drying in the rough drying step is not limited. For example, heating drying, reduced pressure drying, ventilation drying, etc. are mentioned. These may be implemented alone or in combination of two or more.
The means for rough drying is also optional. For example, when rough drying is performed by heat drying, examples of the heat drying means include a hot plate, an oven, infrared irradiation, electromagnetic wave irradiation, and the like. Moreover, as a means of ventilation heating drying, a ventilation drying oven etc. are mentioned, for example. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Although the temperature at the time of rough drying is not limited, it is usually preferably room temperature or higher. In particular, when performing heat drying, the temperature is usually 20 ° C. or higher, preferably 30 ° C. or higher, more preferably 40 ° C. or higher, most preferably 60 ° C. or higher, and usually 200 ° C. or lower, preferably 180 ° C. or lower, more preferably. Is preferably 150 ° C. or lower, most preferably 100 ° C. or lower. In addition, the temperature at the time of heat drying may be constant, but may vary.

The pressure at the time of rough drying is not limited, but particularly when drying under reduced pressure, it is usually not more than normal pressure, preferably not more than 10 kPa, more preferably not more than 1 kPa.
Although the humidity during the rough drying is not limited, in order to prevent moisture absorption of the silica-based precursor, it is usually preferably about 60% RH or less, preferably 30% RH or less at normal pressure, or a vacuum state (humidity 0%) RH).

The atmosphere during rough drying is not limited, and may be an air atmosphere, an inert gas atmosphere such as a nitrogen atmosphere, or a vacuum atmosphere. These may be selected in consideration of the characteristics of the silica precursor. However, it is usually preferable to have a clean atmosphere.
The rough drying time is not limited, and any alcohol, water, or catalyst in the silica-based precursor can be removed, but conditions such as temperature, pressure, and humidity during rough drying, and alcohols contained in the composition And the boiling point of the solvent, the process speed, the characteristics of the silica-based precursor, and the like are preferable. The range is usually 1 second or longer, preferably 1 minute or longer, more preferably 1 hour or longer, and usually 100 hours or shorter, preferably 24 hours or shorter, more preferably 3 hours or shorter.

2-3-2. Acid / base treatment step The silica-based precursor can be brought into contact with an acid or a base after the film formation step described above. This step is preferable because the hydrolysis condensation reaction of the alkoxysilanes of the silica-based precursor can be promoted, and a stable porous film can be formed while maintaining the structure of the silica-based precursor. Preferable acids to be contacted include acids that are easily vaporized such as hydrogen chloride, formic acid, acetic acid, and trifluoroacetic acid. Preferred bases include ammonia, methylamine, dimethylamine, trimethylamine, acylamine, diethylamine, triethylamine, n-propylamine, isopropylamine, n-butylamine, cyclopentylamine, cyclohexylamine, and the like.

As a method of bringing the silica-based precursor into contact with an acid or a base, an acid or base liquid, solution or vapor is used. Moreover, an acid or a base can be dissolved in an organic solvent used in the extraction step described later and contacted simultaneously with the extraction step.
Further, heating may be performed during the acid / base treatment. The heating temperature is usually from room temperature to 40 ° C to 100 ° C, preferably 200 ° C or less, more preferably 180 ° C or less, and particularly preferably 120 ° C or less.

The time for performing the alkali contact treatment is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 30 seconds or more, preferably 10 minutes or more, more preferably 30 minutes or more, and usually 5 hours or less, preferably 2 hours. Hereinafter, more preferably, it is 1 hour or less.
The pressure at the time of performing the alkali treatment is arbitrary as long as the effect of the present invention is not significantly impaired, but may be a reduced pressure environment. In the heating step, the pressure is usually 0.2 MPa or less, preferably 0.15 MPa or less, more preferably. Is 0.1 MPa or less. On the other hand, the lower limit of the pressure is not limited, but is usually 10 ⁻⁴ MPa or more, preferably 10 ⁻³ MPa or more, more preferably 10 ⁻² MPa or more. If the pressure is too low, the volatilization of alcohol proceeds more than the sol-gel reaction of alkoxysilane, and a porous silica film with high hygroscopicity is likely to be formed, which may affect the environmental dependence of optical properties.

2-3-3. Extraction process After the film-forming process described above, a silica-based precursor is brought into contact with a solvent to perform a template material extraction process for making a porous silica material. A porous structure can be obtained by removing the template material from the structure formed by the silica component made of alkoxysilane by contact with the solvent. Furthermore, since the obtained porous silica film has a low refractive index, high optical characteristics are realized.

The solvent used for extraction is not particularly limited, but a substance having a high affinity with the mold material is preferable. This is because if the solvent has a high affinity, the mold material can be easily dissolved and the mold material can be easily removed from the structure formed by the silica component. As the solvent, polar solvents are preferable, and among them, monohydric alcohols, polyhydric alcohols, ketones, ethers, esters, amides, or two or more hydrophilic solvents are preferable. When combining two or more types of hydrophilic solvents, they can be used in combination or can be combined by treating each solvent alone. Furthermore, the same kind of treatment liquid can be repeatedly acted on.

The extraction method is not particularly limited. For example, the silica-based precursor is immersed in a solvent, the surface is washed with a solvent, the solvent is sprayed, and steam is blown. It is also possible to extract the mold material positively by immersing the precursor in a solvent and utilizing ultrasonic waves or stirring the solvent.
Moreover, you may heat in the case of extraction. The heating temperature may usually be 200 ° C. or lower. Preferably it is 180 degrees C or less, More preferably, it is 120 degrees C or less. Moreover, it is usually room temperature or higher, preferably 40 ° C. or higher, more preferably 60 ° C. or higher.

As described above, a laminate having a porous silica film can be obtained by performing an extraction treatment, but it is also possible to carry out a cooling step, a post-treatment step, etc. as necessary after the heating step. .
2-3-4. Drying step The drying step is a step of removing the solvent used for extraction in the extraction step from the porous silica membrane.

At this time, the cooling rate is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 200 ° C. or less, preferably 180 ° C. or less, more preferably 120 ° C. or less, further preferably 100 ° C. or less, and usually room temperature or more. The temperature is preferably 40 ° C. or higher, more preferably 60 ° C. or higher.
Moreover, the atmosphere in a drying process is arbitrary unless the effect of this invention is impaired remarkably, For example, a vacuum environment and an inert gas environment may be sufficient.

2-3-5. Post-treatment step Although there is no limitation on the specific operation performed in the post-treatment step, for example, by treating the obtained porous silica membrane with a silylating agent, the surface of the porous silica membrane is more excellent in functionality. Can be a thing. As a specific example, by treating with a silylating agent, it is possible to impart water repellency, oil repellency, antifouling property, antifogging property, photocatalytic activity, snow sliding property and the like to the porous silica film.

Examples of the silylating agent include trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethylethoxysilane, methyldiethoxysilane, dimethylvinylmethoxysilane, and dimethyl. Alkoxysilanes such as vinylethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane; trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, methyldichlorosilane, dimethylchlorosilane, dimethylvinylchlorosilane, Methyl vinyl dichlorosilane, methyl chloro disilane, triphenyl chloro silane, methyl diphenyl chloro Chlorosilanes such as silane and diphenyldichlorosilane; Silazanes such as hexamethyldisilazane, N, N′-bis (trimethylsilyl) urea, N-trimethylsilylacetamide, dimethyltrimethylsilylamine, diethyltriethylsilylamine, trimethylsilylimidazole; 3,3-trifluoropropyl) trimethoxysilane, (3,3,3-trifluoropropyl) triethoxysilane, pentafluorophenyltrimethoxysilane, pentafluorophenyltriethoxysilane, etc. Alkoxysilanes having a group; and the like. In addition, a silylating agent may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

Specific operations of silylation include, for example, applying a silylating agent to the porous silica film, immersing the porous silica film in the silylating agent, or placing the porous silica film in the vapor of the silylating agent. It can be done by exposing.
Further, as another example of the post-treatment, the porous silica film of the present invention is aged under high humidity conditions, so that unreacted silanol present in the porous structure can be reduced. It is also possible to further improve the environmental resistance. Furthermore, it is possible to improve mechanical strength and alkali resistance by forming another inorganic oxide film on the porous silica film.

2-3-6. Others In the method for producing a porous silica membrane of the present invention, unless the effects of the present invention are significantly impaired, an arbitrary process may be performed at any stage before, during and after the above-described processes. .
2-4. Laminate for optical use In addition, the porous silica film of the present invention is provided on a substrate directly or via another layer. Usually, the porous silica film of the present invention is provided in a film form. It will be.

  The porous silica film can be combined with other layers. In addition to the above-mentioned surface antireflection film, it is appropriately selected according to the application to be used, and in addition to the above-mentioned surface antireflection film, an ultraviolet reflection film, a near infrared reflection film, an infrared reflection film, etc., and a light emitting device such as a display Can be used as a light extraction film (or brightness enhancement film). Specific examples of other layers to be combined include a high refractive index layer, a scattering layer, a metal layer, a polarizing layer, a heat ray blocking layer, an ultraviolet deterioration preventing layer, a hydrophilic layer, an antifouling layer, an antifogging layer, a moisture proof layer, and an antifogging layer. Examples include a layer, a photocatalyst layer, a corrosion-resistant layer, a fingerprint-resistant layer, an adhesive layer, a hard layer, a gas barrier layer, a conductive layer, an antiglare layer, and a diffusion layer. These layers may be formed on any surface of the translucent substrate, and may be laminated on the porous silica film. In addition, these layers may be used individually by 1 type in an optical filter, and may use 2 or more types by arbitrary combinations. Further, as long as the characteristics are not affected, there may be other layers between the above-described structures.

Moreover, the optical use laminated body of this invention can also have an electrode in the surface on the opposite side to the surface in which the porous silica film was formed. It is suitable as a member of an optical device such as a display or a solar cell by forming an optical laminate having an electrode on the surface opposite to the surface on which the porous silica film of the translucent substrate is formed. An example in which the optical application laminate of the invention is configured as a solar cell is shown in FIG. For example, when the optical application laminate of the present invention is configured as a solar cell, the porous silica film 6 and the translucent substrate 5 are usually used for coating on the light receiving surface side that takes in the light energy of the solar cell. To do.

Further, the solar cell is usually configured such that a pair of electrodes 1 and 3 are provided, and the semiconductor layer 2 is positioned between the electrodes 1 and 3.
Further, the intermediate layer 4 may be present between the translucent substrate 5 and the electrode 3. Furthermore, a heat ray blocking layer, an ultraviolet degradation preventing layer, a hydrophilic layer, an antifouling layer, an antifogging layer, a moisture proof layer, an adhesive layer, a hard layer, a conductive layer, a reflective layer, an antiglare layer, a diffusion layer, etc. (not shown) May be combined with

Here, the solar cell is an element or device that can convert light energy into electric power by utilizing the photovoltaic effect, and examples thereof include a single crystal silicon solar cell, a polycrystalline silicon solar cell, and amorphous silicon. Silicon solar cells such as solar cells, CIS solar cells,
Examples include, but are not limited to, compound solar cells such as CIGS solar cells and GaAs solar cells, dye-sensitized solar cells, organic thin film solar cells, multi-junction solar cells, and HIT solar cells.

The semiconductor layer is a layer containing a semiconductor material. In a solar cell, electric energy is usually generated in a semiconductor layer by taking in light, and functions as a battery by taking out the electric energy.
At this time, there is no limitation on the type of semiconductor used for the semiconductor layer. Moreover, only 1 type may be used for a semiconductor and it may use 2 or more types together by arbitrary combinations and a ratio. Further, the semiconductor layer may contain other materials as long as the function as a solar cell is not significantly impaired.

Moreover, the semiconductor layer may be composed of only a single film or may be composed of two or more films. As a specific type, the semiconductor layer in the solar cell may be any of a bulk heterojunction type, a stacked type (hetero pn junction type), a Schottky type, a hybrid type, and the like.
The thickness of the semiconductor layer is not particularly limited, but is usually 5 nm or more, preferably 10 nm or more, and usually 10 μm or less, preferably 5 μm or less.

On the other hand, the electrode can be formed of any material having conductivity. The electrode is for taking out electric energy generated in the semiconductor layer. However, it is preferable that at least one of the pair of electrodes is transparent in accordance with the type of the semiconductor layer (that is, the light absorbed by the semiconductor layer for generating power by the solar cell is transmitted).
Moreover, an electrode can be provided in a board | substrate directly or through another layer. Examples of the electrode include aluminum, tin, magnesium, gold, silver, copper, nickel, palladium, platinum, or an alloy containing these, indium tin oxide (ITO), indium zinc oxide (IZO), indium oxide, and zinc oxide. Among them, indium tin oxide (ITO), indium zinc oxide (IZO), indium oxide, zinc oxide, or a main composition thereof is preferable from the viewpoint of transparency. These are one kind alone, or two or more kinds are arbitrarily selected. Can be used in any combination and ratio. The film thickness is usually 10 nm or more, preferably 40 nm or more, more preferably 80 nm or more, and further preferably 100 nm or more. Moreover, it is 500 nm or less normally, Preferably it is 400 nm or less, More preferably, it is 300 nm or less, More preferably, it is 200 nm or less. If the thickness is less than 10 nm, defects tend to be formed in the film, and if it exceeds 500 nm, the transparency may be impaired.

Furthermore, two or more electrodes may be laminated, and characteristics (electric characteristics, wetting characteristics, etc.) due to surface treatment may be improved.
When the optical application laminate of the present invention is configured as a solar cell, the total light transmittance of C light from the porous silica film to the semiconductor layer is preferably 80% or more, and 83% or more. More preferably, it is more preferably 86% or more, and particularly preferably 90% or more. This is because the higher the light transmittance, the more efficiently the solar cell can generate power. The total light transmittance is ideally 100%, but is usually 99% or less in consideration of partial reflection on the surface of the optical use laminate. Since the silica body of the present invention has a low refractive index and is excellent in abrasion resistance and water resistance, it is possible to exhibit performance very suitable for solar cells in this way.

In addition, even if it is a case where the optical use laminated body of this invention is used for optical uses other than a solar cell, it is preferable that the light transmittance of a porous silica film is high normally. Thereby, the optical use laminate of the present invention can be provided with optical performance and stability of performance effective as a member constituting the optical use member.
Moreover, the optical use laminated body of this invention is suitable also for an electroluminescent (EL) element in the point which is excellent in abrasion resistance and water resistance, and has a smooth surface.

The electroluminescent element of the present invention may be any one as long as it has the porous film of the present invention, two electrodes, and an electroluminescent layer between the electrodes, and is usually (i) an electrode (cathode), (ii) electro It is possible to adopt a configuration in which the luminescence layer, (iii) the electrode (anode), (iv) the porous silica film of the present invention, and (v) the light transmitting body are arranged in this order. As long as the order of (i)-(v) is maintained, you may have another layer between each layer. For example, between (iii) the electrode (anode) and (iv) the porous film of the present invention, a light scattering layer and / or
Alternatively, it is possible to insert a high refractive index layer.

  (I) The material used as the cathode is preferably a metal having a low work function. In particular, it is made of aluminum, tin, magnesium, indium, calcium, gold, silver, copper, nickel, chromium, palladium, platinum, magnesium-silver alloy, magnesium-indium alloy, aluminum-lithium alloy, or the like. In particular, it is preferable to form with aluminum. The thickness of the cathode is usually 10 nm or more, preferably 30 nm or more, more preferably 50 nm or more. Moreover, it is 1000 nm or less normally, Preferably it is 500 nm or less, More preferably, it is 300 nm or less.

(Ii) The electroluminescent layer is formed by a material that exhibits a light emission phenomenon when an electric field is applied. The material includes activated zinc oxide ZnS: X (where X is Mn, Tb , Cu, an activation element of Sm, _{etc.), CaS:. Eu, SrS} : Ce, SrGa 2 S 4: Ce, CaGa 2 S 4: Ce, CaS: Pb, BaAl 2 S 4: conventionally used, such as Eu Inorganic EL materials, 8-hydroxyquinoline aluminum complexes, aromatic amines, low molecular weight organic EL materials such as anthracene single crystals, poly (p-phenylene vinylene), poly [2-methoxy-5- Conjugated polymer organic EL materials such as (2-ethylhexyloxy) -1,4-phenylenevinylene], poly (3-alkylthiophene), and polyvinylcarbazole Etc., can be used organic EL materials are conventionally used. The thickness of the electroluminescence layer is usually 10 nm or more, preferably 30 nm or more, more preferably 50 nm or more, and usually 1000 nm or less, preferably 500 nm or less, more preferably 200 nm or less. The electroluminescent layer can be formed by a vacuum film forming process such as vapor deposition or sputtering, or a coating process using xylene, toluene, cyclohexylbenzene or the like as a solvent.

(Iii) As an anode, indium oxide mixed with tin (usually called ITO)
A composite oxide thin film such as zinc oxide mixed with aluminum (usually called AZO) or zinc oxide mixed with indium (commonly called IZO) is preferably used. In particular, ITO is preferable.
The anode can be a transparent electrode layer that is transparent to visible light. When the anode is formed as a transparent electrode layer, the higher the light transmittance in the visible light wavelength region, the better. In this case, the lower limit is usually 50% or more, preferably 60% or more, more preferably 70% or more. The upper limit is usually 99% or less. In addition, the electrical resistance of the anode is preferably as small as the surface resistance value, and is usually 1Ω / □ (ohm per square; □ = 1 cm ² ) or more, usually 100Ω / □ or less, preferably 70Ω / □ or less, more preferably 50Ω. / □ or less.

Further, the thickness of the anode when the anode is a transparent electrode is not particularly limited as long as it satisfies the light transmittance and the surface resistance described above, but is usually 0.01 μm or more, and has a conductive property. From the viewpoint, it is preferably 0.03 μm or more, more preferably 0.05 μm or more. The upper limit is usually 10 μm or less, preferably 1 μm or less, more preferably 0.5 μm or less from the viewpoint of light transmittance.

Moreover, you may equip the optical use laminated body of this invention with another optical function layer and a protective film, for example. Other optical functional layers can be appropriately selected depending on the application to be used. Further, these layers may be provided with only one layer, or may be provided with an arbitrary combination of two or more layers.
Since the optical use laminate of the present invention includes the porous silica film of the present invention, the refractive index is low and the adhesiveness is excellent. For this reason, if the porous silica film of the present invention is used, optical devices such as lenses, displays, solar cells, solar thermal power generation, low reflection layers, antireflection layers, light control layers and the like used for interior and exterior of building materials and automobiles, etc. It can be suitably used for the optical functional layer.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and can be arbitrarily modified and implemented without departing from the gist of the present invention.
[Example 1]
[Preparation of composition]
Tetraethoxysilane (hereinafter TEOS) 6.78 g, methyltriethoxysilane (MTES) 6.92 g, ethanol (boiling point 78.3 ° C.) 2.30 g, water 5.56 g and 0.3 wt% hydrochloric acid 13.0 g of the aqueous solution was mixed and stirred in a water bath for 30 minutes and further at room temperature for 30 minutes to obtain a mixture (A).

  Next, a mixed solution in which 6.14 g of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer (made by ALDRICH, weight average molecular weight 5650, proportion of ethylene oxide portion 30% by weight) and 3.20 g of ethanol were mixed as a template material. The mixture (A) was added to (B), stirred at room temperature for 60 minutes, and filtered through a 0.45 μm filter (Whatman Japan Co., Ltd.) to prepare the mixture (C).

40 ml of this mixture (C) and 36 ml of 1-butanol (boiling point 117.3 ° C.) as a diluent solvent were mixed and stirred at room temperature for 30 minutes to obtain a silica-based composition.
[Film forming process]
Using the obtained composition as a light-transmitting substrate, a 1 mm thick acrylic plate (Mitsubishi Rayon methacrylic resin plate Acrylite), and using a dip coater (Matsutama Corp. tabletop dip coater TD-150) It was applied on both sides. The dip coater was performed at a lifting speed of 1.7 mm / sec.

[Post-treatment process (coarse drying)]
Next, it was placed in an oven set at 120 ° C. and heated in an air atmosphere for 120 minutes to obtain a silica-based precursor having a good appearance on the substrate.
[Acid / alkali treatment process]
Next, the glass beaker was exposed for 30 minutes at room temperature in a glass beaker filled with an ammonia atmosphere containing 2 ml of aqueous ammonia.

[Extraction process]
Next, it was immersed in an ethanol solution at room temperature for 1 minute, and the mold material was removed with an ultrasonic cleaner (desktop ultrasonic cleaner W-113 manufactured by Honda Electronics Co., Ltd.) over 1 minute.
[Drying process]
Next, it was placed in an oven set at 60 ° C., and dried for 10 minutes in an air atmosphere to obtain a silica film laminate having a good appearance.

<< Calculation of refractive index and film thickness >>
As a result of measuring the reflectance with a spectral film thickness meter (FE-3000 manufactured by Otsuka Electronics Co., Ltd.), the minimum reflectance at 550 nm of the porous silica film obtained on the translucent substrate was 1.38%. As a result of calculating the refractive index using the formula: Moreover, it was 164 nm as a result of calculating a film thickness from the calculated refractive index and the said wavelength. The visible light transmittance of the laminate was 97%.

《Abrasion test》
As a result of reciprocating 20 times on the surface of the porous silica film obtained by loading the cheese cloth described in Mil-Spec MIL-CCC-c-440 with a load of 500 g / cm ² , the visible light transmittance of the laminate was 96%, and wear The amount of change from the visible light transmittance before the test was 1%.
<Peel test>
A Scotch tape (manufactured by Sumitomo 3M Co., Ltd.) was applied to the surface of the obtained porous silica film so as not to enter air, and then peeled off. The result is ○ when the adhesion between the base material and the porous silica film is good (when there is no deposit on the tape), and x when the adhesion is poor (when there is a deposit on the tape). did.

As a result of the peeling test of Example 1, nothing adhered to the tape, and the adhesion between the substrate and the porous silica film was good.
[Comparative Example 1]
A laminate having a porous silica film was obtained in the same manner as in Example 1 except that the [acid / alkali treatment step] and the [extraction treatment step] in Example 1 were not performed.

  << Refractive index and film thickness calculation >> << Abrasion test >> << Peel test >> were also performed in the same manner as in Example 1. The minimum reflectance at 550 nm was 3.56%, the refractive index was 1.455, and the film thickness was 130 nm. there were. The visible light transmittance was 95%. The visible light transmittance after the abrasion test was 72%, and the change from the visible light transmittance before the abrasion test was 23%. In the peel test, it was confirmed that the porous silica film adhered to the tape, and the adhesion between the translucent substrate and the porous silica film was not sufficient.

[Comparative Example 2]
In the film forming process of Example 1, a large slide glass (S112 manufactured by Matsunami Glass Industrial Co., Ltd.) was used as a translucent substrate, and coating was performed with a spin coater (MS-A150 manufactured by Mikasa). The spin coater was set to a rotation speed of 500 rpm, a rotation time of 120 seconds, and a coating liquid amount of 1 ml. Next, by heating for 10 minutes in an oven set at 450 ° C., a laminate having a porous silica film having a good appearance on a translucent substrate was obtained.

  << Refractive index and film thickness calculation >> << Abrasion test >> << Peel test >> were also performed in the same manner as in Example 1. The minimum reflectance at 550 nm was 0.15%, the refractive index was 1.26, and the film thickness was 105 nm. there were. The visible light transmittance was 95%. The visible light transmittance after the abrasion test was 89%, and the change from the visible light transmittance before the abrasion test was 6%. In the peel test, it was confirmed that the porous silica film adhered to the tape, and the adhesion between the translucent substrate and the porous silica film was not sufficient.

  The evaluation results of Example 1 and Comparative Examples 1 and 2 are shown in Table 1.

1, 3 electrodes
2 Semiconductor layer
4 middle class
5 Transparent substrate
6 Porous material

Claims (5)

A laminated body having a porous silica film having a refractive index of 1.20 to 1.35 on a translucent substrate having a Tg of 200 ° C. or less, the mil-spec MIL-CCC-c-440 In the abrasion resistance test in which the cheese cloth is subjected to 20 reciprocations on the surface of the porous silica film with a load of 500 g / cm ² , the amount of change in the visible light transmittance of the laminate is the visible light transmittance of the laminate before the test. A laminate having a content of less than 5%.   The laminate according to claim 1, wherein the translucent substrate has a thickness of 0.01 to 80 mm.   The laminate according to claim 1 or 2, wherein the porous silica film has a surface roughness Ra of 8 nm or less.   The material of the translucent base material is any one or more selected from the group consisting of polyethylene terephthalate, polymethyl methacrylate, polycarbonate, and tetrafluoroethylene-ethylene copolymer. The laminated body of any one of -3.   A method for producing a laminate having a porous silica film on a translucent substrate having a Tg of 200 ° C. or lower, wherein the composition containing an alkoxysilane compound, water, an organic solvent, and an organic polymer is a Tg of 200 ° C. or lower. A method for producing a laminate having a porous silica film, comprising the step of extracting the organic polymer after wet-coating on the translucent substrate.

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