JP2012031054A - Ceramic porous body - Google Patents

Abstract

A porous body excellent in transparency, refractive index, and abrasion resistance is provided.
A porous ceramic body containing an alkyl group having 3 to 12 carbon atoms and having a minimum surface reflectance of 1% or less.
[Selection figure] None

Description

  A ceramic porous body is a ceramic material having pores of nanometer to millimeter size, and is expected as a structure that exhibits various functions. For example, a solid catalyst with a catalytically active group modified in the pores, a gas separator utilizing adsorption / desorption of molecules, an optical film utilizing low refractive index or low dielectric constant derived from a porous structure, An insulating film is mentioned. In particular, in the optical film and the insulating film, since the porosity of the ceramic porous body is directly linked to the performance such as the refractive index and the dielectric constant, there have been reports of increasing the porosity.

  Conventionally, a porous silica material having a high porosity has been reported by forming voids between particles from a bead-like silica string composed of colloidal silica and a tetraethoxysilane (Patent Document 1). ). In this method, because the surface of the porous silica material has particle-like irregularities in the nanometer size, the friction coefficient increases, and in order to obtain a high porosity, the number of binding sites between silica strings is extremely small. Mechanical strength against wear is weak. Moreover, since it is comprised from the silica string of 30-200 nm of average length, haze (Example 0.5-0.9%) is large, and there exists a problem also in transparency.

  Patent Document 2 reports a ceramic porous body having high wear properties from hollow silica particles having an aggregate particle diameter of 60 to 400 nm and a metal oxide. As far as the examples are concerned, although the haze is low and the transparency is excellent, when this method is used as a porous silica material having an optimal refractive index with respect to the refractive index of the substrate, it is optimal simultaneously with the above transparency. It was difficult to achieve both good antireflection performance. This is because the porous silica is composed of hollow silica particles having an agglomerated particle diameter of 1/4 or more with respect to the wavelength. If the film thickness is smaller than the agglomerated particles, the film surface becomes rough and transparent. The performance is expected to be significantly reduced. In other words, in order to ensure transparency, it is necessary to set the film thickness to a certain value (size of aggregated particles) or more, which makes it difficult to perform an optimal antireflection design. Further, since the hollow silica particles have a porosity of about 50% (specification [0054]) at the maximum, the porosity becomes less than 50% when a binder is added, so that it is difficult to sufficiently reduce the refractive index.

In patent document 3, the silica porous body with high abrasion resistance is obtained by thermosetting the composition which consists of a silica particle with a particle diameter of 10-60 nm at the temperature of 600 degreeC or more. In this method, only a glass substrate can be used due to a very high heat treatment temperature. Further, the condensation reaction of the silica component proceeds excessively due to the high temperature treatment, the porosity is lowered, and the refractive index is increased.
In the case of Patent Document 4, by adding a polymer to alkoxysilane composed of methyltriethoxysilane and tetraethoxysilane, the polymer in the condensation-reacted silica is removed to obtain a porous silica body having high porosity. ing. In this method, it is possible to stably produce a porous silica by adding alkoxysilanes having 1 to 2 functional alkyl groups, but the adhesion between the silica component and the substrate depends on the type of the substrate. May become weak and sufficient mechanical strength may not be exhibited.

WO2004 / 07392 JP 2006-335881 A Special table 2004-511418 JP 2009-73722 A

  The subject of this invention is providing the porous body excellent in transparency (haze), a refractive index (minimum reflectance), and abrasion resistance.

As a result of investigations by the present inventors, a ceramic porous body having an alkyl group having 3 to 12 carbon atoms and having a minimum surface reflectance of 1% or less has transparency, refractive index (minimum reflectance), The present inventors have found that it is excellent in wear and have reached the present invention.
That is, the gist of the present invention is as follows.
(1) A ceramic porous body containing an alkyl group having 3 to 12 carbon atoms and having a minimum surface reflectance of 1.5% or less.
(2) The porous ceramic body according to (1), which contains a positive element containing silicon and the silicon content is 50 mol% or more with respect to the positive element content.
(3) A ceramic porous material comprising a base material and the ceramic porous body according to (1) or (2) having a film thickness of 0.05 to 3 μm provided on the base material. Quality laminate. (4) The porous ceramic laminate according to (3), wherein the Tg of the substrate is 200 ° C. or lower.
(5) An optical member comprising a substrate and the ceramic porous body according to (1) or (2) provided on the substrate.
(6) An antireflection laminate comprising a substrate and the ceramic porous body according to (1) or (2) provided on the substrate.

  According to the present invention, it is possible to provide a porous body having high antireflection performance and excellent wear characteristics.

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. Ceramic porous body [C3-C12 alkyl group]
The ceramic porous body of the present invention has an alkyl group having 3 to 12 carbon atoms. The alkyl group of the ceramic porous body of the present invention preferably has 3 to 10 carbon atoms, and most preferably 5 to 8 carbon atoms. When the number of carbon atoms is less than 3, the wear resistance is lowered. When the number of carbon atoms is more than 12, the porous structure cannot be stably produced, and the antireflection property is significantly lowered due to the lowered porosity.

  Examples of the alkyl group of the ceramic porous body of the present invention include propyl, n-butyl, isobutyl, t-butyl, pentyl, isopentyl, hexyl, isohexyl, phenyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, Among them, propyl, n-butyl, isobutyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl and dodecyl are preferable, and n-butyl, isobutyl, pentyl, hexyl and heptyl are more preferable.

[Porous structure]
The ceramic porous body of the present invention is a nonmetallic material and an inorganic material having a porous structure having pores. The material may be crystalline or non-crystalline, but non-crystalline is preferable from the viewpoint of following the substrate. Specific examples include metal oxides such as silicon oxide, titanium oxide, and aluminum oxide, and metal nitrides such as silicon nitride.

The porous structure is not particularly limited, and the pores are usually connecting holes connected to a tunnel or independent pores, but the detailed pore structure 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.
[Hole size]
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. 0.5 to 200 nm is preferable, 0.8 to 100 nm is more preferable, and 1 to 80 nm is most preferable. 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 impaired, and haze such as scattering occurs.

[Porosity]
The porosity is not particularly limited, but the average porosity is preferably 10 to 90%, more preferably 20 to 85%, and still 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 impaired, and haze such as scattering occurs.

[Main component]
In order to obtain excellent wear resistance while maintaining antireflection properties, it is important to contain an alkyl group having 3 to 12 carbon atoms. However, the porous ceramic body of the present invention mainly contains silicon oxide. It is preferable to use as a component. The content of the silicon element in the ceramic porous body is not particularly limited as long as the effects of the present invention are not significantly impaired. For example, the ratio of silicon to all positive elements including silicon is usually 50 mol% or more, preferably Is 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 ceramic porous body increases and the mechanical strength may also decrease. Moreover, the higher the silicon content, the more porous the ceramic body is. The upper limit is ideally 100 mol%.

  Moreover, what is necessary is just to contain the C3-C12 alkyl group, and you may mix several alkyl groups which have different carbon number. Furthermore, alkyl groups other than the above carbon number can also be contained. More preferably, it has 4 to 10 carbon atoms, and most preferably 5 to 8 carbon atoms. When the number of carbon atoms is less than 3, the wear resistance is lowered, and when the number of carbon atoms is more than 12, the porous structure cannot be stably produced, and there is a possibility that the antireflection property is significantly lowered due to the lowered porosity.

[Minimum reflectivity]
From the viewpoint of achieving both the antireflection property and the wear resistance of the porous ceramic body of the present invention, the minimum reflectance of the surface is 1.5% or less. More preferably, it is 1.0% or less, More preferably, it is 0.5% or less, Most preferably, it is 0.2% or less. If it exceeds 1.5%, not only the antireflection property is lowered, but also the surface is easily roughened due to the porous structure, and this surface structure also adversely affects the wear resistance. On the other hand, if it is less than 0.01%, dirt attached to the surface of the ceramic porous body tends to affect the antireflection property, so that there is a possibility that applicable applications are limited.

The minimum reflectance refers to a value at a wavelength of 400 nm to 1000 nm measured by an optical method such as reflection spectrum measurement.
[Refractive index]
The ceramic porous body of the present invention preferably has a refractive index of 1.3 or less. Among these, 1.28 or less is preferable, 1.27 or less is more preferable, and 1.25 or less is particularly preferable. More preferably, it is 1.23 or less. If the refractive index is too large, the distortion in the ceramic porous body of the present invention may increase and become weak against external force. On the other hand, the lower limit of the refractive index is not particularly limited, but is usually 1.05 or more, preferably 1.08 or more. If the refractive index is too small, the mechanical strength of the ceramic porous body of the present invention may be significantly reduced.

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.

Further, in the case of a ceramic porous body provided on a base material having a large center line average roughness, the refractive index can be estimated also by reflectance spectral spectrum measurement, and the measurement region is preferably 10 μm or less. .
〔thickness〕
Although there is no restriction | limiting in particular in the thickness of the ceramic porous body of this invention, in order to use as an optical function layer and also from a viewpoint of the abrasion resistance of a film | membrane, 0.05-50 micrometers is preferable, 0.05 -5 μm is more preferable, 0.05-3 μm is more preferable, 0.07-3 μm is more preferable, 0.09-1 μm is further preferable, and 0.11-0.5 μm is most preferable. If 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 50 μm, the porous structure in the film thickness direction becomes inhomogeneous, strain may remain in the porous body, and there is a risk of adversely affecting the wear resistance. .

〔shape〕
The shape of the ceramic porous body of the present invention is not particularly limited, but is preferably a film. The thickness of the ceramic porous body can be the same as the above film thickness. Moreover, when using a ceramic porous body as an optical function layer, it is preferable to provide a ceramic porous body 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.

(Static contact angle)
The ceramic porous body of the present invention needs to be laminated with other layers and base materials depending on the application. In such a case, it is preferable to control the static contact angle of the surface. Specifically, the static contact angle with respect to water after heat treatment for 1 hour is usually 25 ° or more, particularly 30 ° or more, particularly 33 °. Preferably, the angle is 90 ° or less, preferably 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 ceramic body becomes too high, moisture tends to be adsorbed on the surface, and adhesion with other layers may be reduced. On the other hand, if the static contact angle is too large, the surface of the ceramic body is in a hydrophobic state, and there is a possibility that restrictions on the layer to be laminated and the substrate are increased. The heat treatment is usually performed at a temperature of 200 ° C. When the substrate is a resin, it can be performed at a temperature lower than the glass transition temperature of the resin substrate.

  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, water drops are dropped on the surface of the ceramic body, and the contact angle of the water drops 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.

[Smoothness]
The ceramic porous body of the present invention preferably has a surface roughness Ra of 7 nm or less. Among these, 5 nm or less is preferable, 3 nm or less is more preferable, and 1 nm or less is particularly preferable. If the surface roughness Ra is too large, the homogeneity of the ceramic porous body may be inferior. On the other hand, the lower limit of the surface roughness Ra is not limited, but is usually 0.2 nm or more, preferably 0.3 nm or more. If the surface roughness Ra is too small, the distortion of the ceramic porous body may become extremely large, and there is a risk of adversely affecting the wear resistance. Therefore, the abrasion resistance is preferably within the above range.

The surface roughness Ra is based on the standard defined in JIS B0601: 2001, using a P-15 type contact surface roughness meter manufactured by KLA Tencor Co., Ltd. with a scanning distance of 0.5 μm. The average value measured several times can be calculated and obtained.
〔water resistant〕
In the ceramic porous body of the present invention, when the ceramic porous body of the present invention is formed into a film and used for optical applications, it is important to control the optical film thickness (product of refractive index and film thickness). Therefore, it is preferable that the change in the film thickness before and after the immersion treatment in water is small. 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 water immersion treatment may be immersed in water at room temperature (25 ° C.) for 24 hours.

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 ceramic porous body 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. Further, the total area of the region where the crack does not exist within 1 mm × 1 mm is preferably 50% or more, more preferably 70% or less, and further preferably 85% or more with respect to the ceramic porous body surface. If it is less than 50%, the stability and appearance of the optical performance may be lowered as an optical application.

  In addition, there is “high temperature and high humidity treatment” as an evaluation of heat and moisture resistance. That is, after the refractive index n1 of the ceramic body of the present invention at a wavelength of 550 nm is measured in advance, the ceramic 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 ceramic body 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. Ceramic Porous Laminate The ceramic porous laminate of the present invention comprises a base material and the ceramic porous body of the present invention provided on one or both surfaces of a light-transmitting base material. Moreover, the ceramic porous laminated body of this invention may be equipped with members other than a base material and a ceramic porous body as needed.

3. Substrate Any substrate can be used depending on the application. Especially, it is preferable to use the translucent base material which consists of a general purpose material. 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 total light transmittance at a wavelength of 550 nm of the translucent substrate is usually 65% or more, preferably 70% or more, more preferably 75% or more. Further, the light-transmitting substrate may have scattering or haze as long as it does not affect the performance. In addition, although this wavelength is not limited to the range of visible light, in a solar cell use, the high transmittance | permeability of a visible light region is preferable.

〔material〕
Examples of light-transmitting substrate materials include silicate glass, high silicate glass, alkali silicate glass, lead alkali glass, soda lime glass, potash lime glass, barium glass and other silicate glasses, borosilicate glass and alumina silicate glass. Glass such as phosphate glass and tempered glass thereof; acrylic resin such as polymethyl methacrylate and cross-linked acrylate; aromatic polycarbonate resin such as bisphenol A polycarbonate; polyester resin such as polyethylene terephthalate; amorphous polyolefin such as polycycloolefin Resin, epoxy resin, styrene resin such as polystyrene, polysulfone resin such as polyethersulfone, synthetic resin such as polyetherimide resin, fluorine-containing resin such as ETFE, PFA, PCTFE, ECTFE, PVDFPVF And the like. These can be used alone or in any combination of two or more.

  Among them, glass, aromatic polycarbonate resin, polyetherimide resin, polyester resin, and polysulfone resin are preferable from the viewpoint of dimensional stability. From the viewpoint of weather resistance, fluorine-containing resin, soda lime glass, aromatic polycarbonate resin, amorphous Polyolefin resins are preferred. Furthermore, it is also preferable to use tempered glass or aromatic polycarbonate resin from the viewpoint of impact resistance.

  For example, when a solar cell cover glass is used as a light-transmitting substrate, the ceramic porous body functions as an antireflection film on the surface of the light-transmitting substrate, thereby realizing an improvement in output. Since the ceramic porous body of the present invention is excellent in durability, it is suitable for such applications. In addition, when using a solar cell cover glass used for a solar cell capable of photoelectric conversion even in the near-infrared light such as a single crystal solar cell and a polycrystalline solar cell, it is contained in a normal soda-lime glass. The divalent iron ions absorb in the near-infrared region, and therefore it is preferable to increase the light transmittance by reducing the iron ion content. More preferably, it is used as a material.

  When used for a cover glass for a solar cell, the total transmittance of C light of the ceramic porous body and the transparent substrate is preferably 75% or more, more preferably 80% or more, and 85%. More preferably, it is more 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 solar cell.

  A 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 a microcrystalline silicon solar cell. , Silicon solar cells such as amorphous silicon solar cells, CIS solar cells, CIGS solar cells, compound solar cells such as GaAs solar cells, dye-sensitized solar cells, organic thin film solar cells, and multi-junction solar cells, Although a HIT solar cell is mentioned, it is not specifically limited to these. Moreover, in thin film solar cells such as amorphous silicon solar cells, CIS solar cells, CIGS solar cells, GaAs solar cells and other compound solar cells, dye-sensitized solar cells, and organic thin film solar cells, A ceramic porous body may be provided on one side, and a transparent electrode layer may be provided on the other side.

〔Glass-transition temperature〕
In a resin base material other than glass, the glass transition temperature of the base material is preferably 200 ° C. or lower. More preferably, it is 180 degrees C or less, More preferably, it is 150 degrees C or less, Most preferably, it is 120 degrees C or less. Although there is no restriction | limiting in particular in a lower limit, Preferably it is 50 degreeC or more, More preferably, it is 70 degreeC or more, Most preferably, it is 80 degreeC or more. When the temperature exceeds 200 ° C., the thermal contraction of the resin substrate due to the heat treatment during film formation increases, and there is a risk that peeling or local defects may occur at the interface with the ceramic porous body having a small linear expansion. On the other hand, when the temperature is lower than 50 ° C., there is a risk that it becomes difficult to form a porous structure due to a shape change of the resin base material due to heat treatment during film formation, and as a result, high antireflection performance cannot be obtained.

The thickness of the resin substrate is usually 3 mm or less, more preferably 1 mm or less, still more preferably 0.5 mm or less, and most preferably 0.3 mm or less. If it is too thick, the stress of the resin base material that expands and contracts due to the heat treatment during film formation remains in the porous body, which may deteriorate the wear resistance. On the other hand, the lower limit is usually 0.01 mm or more, preferably 0.02 mm or more, more preferably 0.05 or more, and most preferably 0.07 or more. Below the lower limit, the substrate may be deformed by the curing reaction of the porous body formed during film formation.
Moreover, in the case of a resin base material, you may surface-treat on a film forming surface. Specific examples include corona treatment, UV ozone treatment, and plasma treatment. From the viewpoint of adhesion between the substrate and the porous body, corona treatment and plasma treatment are preferred.

〔Size〕
The dimension of a translucent base material is 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 0.1 mm or more, from the viewpoint of mechanical strength and gas barrier properties, and 1 mm. The above is more preferable. The thickness is preferably 80 mm or less, more preferably 50 mm or less, and particularly preferably 30 mm or less, from the viewpoints 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.

[Roughness]
Moreover, the centerline average roughness of the translucent substrate is also arbitrary. However, from the viewpoint of film forming properties of the ceramic porous body 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.
On the other hand, when imparting antiglare properties, the center line average roughness of the translucent substrate is not limited to the above, and the surface of the translucent substrate preferably has irregularities. Such irregularities may be provided on only one side or both sides of the translucent substrate, but are preferably provided on the surface on which the ceramic porous body is laminated.

  The centerline average roughness in such a case is usually 0.1 μm or more, preferably 0.2 μm or more, more preferably 0.4 μm or more, and usually 15 μm or less, preferably 10 μm or less. The maximum height Rmax of the surface roughness is usually 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.5 μm or more, particularly preferably 0.8 μm or more, usually 100 μm or less, preferably 80 μm or less. More preferably, it is 50 μm or less, more preferably 30 μm or less, and particularly preferably 10 μm or less. By providing the ceramic porous body of the present invention on the translucent substrate in the range of the maximum height Rmax of the centerline average roughness and the surface roughness, it has excellent low reflection characteristics and antiglare properties. An optical filter or the like can be provided. Below or above this range, the low reflection effect may be impaired and the appearance may become opaque. Moreover, the average interval Sm of the irregularities on the surface of the light-transmitting substrate is usually 0.01 mm or more, preferably 0.03 mm or more, and can usually be 30 mm or less, preferably 15 mm or less. The centerline average roughness, the maximum height Rmax of the surface roughness, and the average interval Sm of the irregularities are general-purpose surface roughness meters according to JIS-B0601: 1994 (for example, Surfcom 570A manufactured by Tokyo Seimitsu Co., Ltd.) Measured by

[Others]
Moreover, when a ceramic porous body is applied to optical devices such as solar cells, organic electroluminescence, inorganic electroluminescence, and LEDs, electrodes may be formed on one side or both sides of a translucent substrate to be used. An electrode can be provided in a translucent base material directly or through another layer. Examples of the electrode material 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, zinc oxide, and the like can be given. Two or more kinds can be used in any ratio and combination. Among these, indium tin oxide (ITO), indium zinc oxide (IZO), indium oxide, zinc oxide, or a main composition thereof is preferable from the viewpoint of transparency.

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 3,000 nm or less normally, Preferably it is 1,000 nm or less, More preferably, it is 500 nm or less, More preferably, it is 200 nm or less. If the thickness is less than 10 nm, the ceramic porous body tends to be defective, and if it exceeds 3,000 nm, the transparency may be impaired.
It is also possible to use an organic transparent electrode on the translucent substrate. In this case, it is also possible to combine with the above inorganic electrode. As the organic transparent electrode, for example, a conductive polymer such as PEDOT can be used.

4). Optical member The porous ceramic body of the present invention can also be applied to an optical member. The optical member referred to in the present invention refers to a filter that controls phenomena such as reflection, transmission, and diffraction of light passing through a light-transmitting substrate, but is not limited thereto. Since the ceramic porous body of the present invention has extremely low minimum reflectance, it is easy to control these light phenomena and at the same time has excellent wear resistance, so it can be applied to various products as an optical member. Is possible. Usually, the laminated body which provided the ceramic porous body of this invention on the above-mentioned base material is used as an optical member.

Specifically, functions such as designability and visibility can be imparted by using the optical member as an antireflection laminate that prevents reflection of light on the surface of the translucent substrate.
The ceramic porous body of the present invention is used as a visible light reflecting film, an ultraviolet reflecting film, a near infrared reflecting film, an infrared reflecting film or the like in combination with other layers as necessary.
Furthermore, it can be used as a light capturing film or a light confining film by applying it to a power generation device such as solar power generation, and it can also be used as a light extraction film (or brightness enhancement film) by applying it to a light emitting device such as a display or illumination Can be used.

There is no restriction | limiting in particular as an application of an optical member, Display devices, such as said electric power generation devices, such as the said solar cell, organic electroluminescence, inorganic electroluminescence, and liquid crystal, illumination devices, such as LED, etc. are mentioned. In particular, in the present invention, since it is easy to increase the area of the base material, application to a power generation device such as a solar cell or a large display device is effective.
Even when the porous ceramic body of the present invention is used for optical applications other than the above solar cells, it is usually preferable that the light transmittance of the porous ceramic body is high. This is because the ceramic porous body can be provided with stable and effective optical performance.

[Other layers]
The other layers used in the optical member are appropriately selected according to the type and use of the optical member. For example, a high refractive index layer, a scattering layer, a metal layer, a heat ray blocking layer, an ultraviolet degradation preventing layer, a hydrophilic layer, a protective layer. Examples include a fouling layer, an antifogging layer, a moisture proof 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 ceramic porous body. In addition, these layers may be used individually by 1 type in an optical member, and may use 2 or more types by arbitrary combinations.

5. Method for Producing Ceramic Porous Body The ceramic porous body of the present invention is usually a kind selected from the alkoxysilane group consisting of alkoxysilanes having an alkyl group having 3 to 12 carbon atoms, hydrolysates and partial condensates thereof ( Hereinafter, it is also referred to as “alkoxysilane compound” as appropriate)), a surfactant, an organic solvent, and a ceramic composition containing water on a translucent substrate to form a ceramic precursor. The ceramic precursor is heated through a heating step to make a ceramic porous body.
Hereinafter, the ceramic composition used in the present invention will be described in detail.

[Ceramic composition]
The ceramic composition used in the method for producing a ceramic porous body of the present invention includes an alkoxysilane compound having an alkyl group having 3 to 12 carbon atoms, a surfactant, an organic solvent, and water. Details are described below.

[Alkoxysilane compound]
In order to obtain high abrasion resistance while maintaining high antireflection properties, it is important to have an alkyl group having 3 to 12 carbon atoms. Therefore, the alkoxysilane compound used in the present invention has 3 carbon atoms. There is no particular limitation as long as it contains an alkoxysilane group having ˜12 alkyl groups, but it is preferable to contain one or both of the following first and second compounds (group).

(First compound (group))
At least one selected from an alkoxysilane group having an alkyl group having 3 to 12 carbon atoms (that is, a group consisting of an alkoxysilane having an alkyl group having 3 to 12 carbon atoms, a hydrolyzate and a partial condensate thereof), and tetra At least one selected from the group of alkoxysilanes (namely, the group consisting of tetraalkoxysilanes, hydrolysates and partial condensates thereof), and other groups of alkoxysilanes (namely, other alkoxysilanes, hydrolysates and parts thereof) A combination with at least one selected from the group consisting of condensates.

(Second compound (group))
Specific partial condensate (that is, partial condensation of at least one selected from alkoxysilanes having an alkyl group having 3 to 12 carbon atoms, at least one selected from tetraalkoxysilanes, and at least one selected from other alkoxysilanes object).
(Alkoxysilanes having an alkyl group having 3 to 12 carbon atoms)
There is no restriction | limiting in the kind of alkoxysilane which has a C3-C12 alkyl group. Examples of suitable ones include propyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, t-butyltrimethoxysilane, pentyltrimethoxysilane, isopentyltrimethoxysilane, hexyltrimethoxysilane, isohexyltrimethoxy. Silane, phenyltrimethoxysilane, heptyltrimethoxysilane, octyltrimethoxysilane, 2-ethylhexyltrimethoxysilane, nonyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, propyltriethoxysilane, butyltriethoxysilane, isobutyl Triethoxysilane, t-butyltriethoxysilane, pentyltriethoxysilane, isopentyltriethoxysilane, hexyltriethoxysilane, Hexyltriethoxysilane, phenyltriethoxysilane, heptyltriethoxysilane, octyltriethoxysilane, 2-ethylhexyltriethoxysilane, nonyltriethoxysilane, decyltriethoxysilane, dodecyltriethoxysilane, propyltri (n-propoxy) silane Butyltri (n-propoxy) silane, isobutyltri (n-propoxy) silane, t-butyltri (n-propoxy) silane, pentyltri (n-propoxy) silane, isopentyltri (n-propoxy) silane, hexyltri (n- Propoxy) silane, isohexyltri (n-propoxy) silane, phenyltri (n-propoxy) silane, heptyltri (n-propoxy) silane, octyltri (n-propoxy) silane, 2-e Hexyl tri (n- propoxy) silane, Nonirutori (n- propoxy) silane, Deshirutori (n- propoxy) silane, Dodeshirutori (n- propoxy) silane, and the like.

The carbon number of the alkyl group that the alkylalkoxysilane has is more preferably 3 to 10 carbon atoms, and most preferably 5 to 8 carbon atoms. When the number of carbon atoms is less than 3, the wear resistance is lowered. When the number of carbon atoms is more than 12, the porous structure cannot be stably produced, and the antireflection property is significantly lowered due to the lowered porosity.
Two or more of these alkyl groups having different carbon numbers may be mixed.

(Tetraalkoxysilane group)
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 and the like. Examples of the tetraalkoxysilane group include hydrolysates and partial condensates (such as oligomers) of the above tetraalkoxysilanes.

From the viewpoint of the stability of the ceramic precursor in the rough drying step described later, tetramethoxysilane, tetraethoxysilane, and oligomers thereof are preferable, and tetraethoxysilane is more preferable.
However, since tetraalkoxysilanes tend to undergo hydrolysis and partial condensation over time, even when only tetraalkoxysilanes are prepared, the hydrolysates and partial condensates of tetraalkoxysilanes are usually tetraalkoxysilanes. Often co-exists with other species.

In addition, the compound which belongs to the tetraalkoxysilane group may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
(Other alkoxysilane groups)
Any other alkoxysilane can be used as long as it is an alkoxysilane that does not belong to the above-mentioned alkoxysilane group having an alkyl group of 3 to 12 carbon atoms or tetraalkoxysilane group. Examples of suitable ones include trialkoxysilanes such as trimethoxysilane, triethoxysilane, methyltrimethoxysilane, and ethyltrimethoxysilane; dialkoxysilanes such as dimethyldimethoxysilane and dimethyldiethoxysilane; bis (tri Trialkoxysilyl groups having two or more organic residues such as methoxysilyl) methane, bis (triethoxysilyl) methane, 1,2-bis (trimethoxysilyl) ethane, 1,2-bis (triethoxysilyl) ethane 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-acryloyloxy B pills trimethoxysilane, alkyl group having a reactive functional group to be substituted with a silicon atom, such as 3-carboxypropyl trimethoxysilane; and the like. Examples of other alkoxysilane groups include hydrolysates and partial condensates (such as oligomers) of the other alkoxysilanes. Examples include 3-trihydroxysilyl-1-propane-sulfonic acid.

Of these, monoalkylalkoxysilanes and dialkylalkoxysilanes having an aromatic hydrocarbon group or an aliphatic hydrocarbon group are preferred. Specifically, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethylsilane, decyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-glycol. Sidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, trifluoropropyltrimethoxysilane, triethoxy- Preferred examples include 1H, 1H, 2H, 2H-tridecafluoro-n-octylsilane and the like.

  However, other alkoxysilanes tend to undergo hydrolysis and partial condensation over time, so even if only other alkoxysilanes are prepared, other alkoxysilane hydrolysates and partial condensates are usually other. Often coexists with other alkoxysilanes. In addition, the compound which belongs to other alkoxysilanes may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

(Preferred combination)
You may use together the alkoxysilane group which has a C3-C12 alkyl group mentioned above, and the above-mentioned tetraalkoxysilane group or / and another tetraalkoxysilane group.
Among the combinations of the above-mentioned alkoxysilane group having 3 to 12 carbon alkyl groups, tetraalkoxysilane group, and other tetraalkoxysilane groups, particularly preferred combinations include alkylalkoxysilanes having 3 to 12 carbon atoms. , Monoalkylalkoxysilanes having aliphatic hydrocarbon groups, tetraethoxysilanes as tetraalkoxysilanes, monoalkylalkoxysilanes or dialkylalkoxys having aliphatic hydrocarbon groups of 1 to 2 carbon atoms as other alkoxysilanes A combination with silane is mentioned. According to this combination, a ceramic composition having excellent coating properties can be prepared.

(Partial condensate of an alkoxysilane group having a C 3-12 alkyl group and a tetraalkoxysilane group or / and another alkoxysilane group)
As an alkoxysilane compound, the partial condensate of the alkoxysilane group which has a C3-C12 alkyl group, and the tetraalkoxysilane group or / and another alkoxysilane group can also be used. Specifically, a partial condensate of an alkoxysilane group having a C3-12 alkyl group and a tetraalkoxysilane group, an alkoxysilane group having a C3-12 alkyl group, and another alkoxysilane group. A partial condensate is a partial condensate of an alkoxysilane group having a C 3-12 alkyl group, a tetraalkoxysilane group, and another alkoxysilane group.

Among these, a partial condensate (second compound (group)) of an alkoxysilane group having 3 to 12 carbon atoms, a tetraalkoxysilane group, and another alkoxysilane group is preferable.
The partial condensate may be used alone or in combination of two or more. Moreover, you may use together the said partial condensate and 1 or more types chosen from the group which consists of an alkoxysilane group which has a C3-C12 alkyl group, a tetraalkoxysilane group, and another alkoxysilane group. .

(Ratio of alkoxysilane compound)
In the ceramic composition used in the present invention, the content ratio of the alkoxysilane compound having an alkyl group having 3 to 12 carbon atoms is not particularly limited. However, from the viewpoint of pore formation in the ceramic porous body, the ratio of silicon atoms derived from alkoxysilanes having an alkyl group having 3 to 12 carbon atoms to silicon atoms derived from all alkoxysilane compounds is usually 0.05 (mol / Mol) or more, preferably 0.1 or more, more preferably 0.13 or more, and most preferably 0.15 or more. Moreover, it is 0.75 or less normally, Preferably it is 0.7 or less, More preferably, it is 0.6 or less, Most preferably, it is 0.5 or less. If the upper limit is exceeded, unreacted silanol tends to remain, which may reduce the water resistance of the porous body or cause a decrease in antireflection properties due to a decrease in porosity. On the other hand, if the value is below the lower limit, the wear resistance is low, and there is a risk that it is easily scratched or easily worn.

  Moreover, it is good to use a tetraalkoxysilane compound from a viewpoint of film forming property. In that case, the ratio of silicon atoms derived from tetraalkoxysilanes to silicon atoms derived from all alkoxysilane compounds is usually 0.1 (mol / mol) or more, preferably 0.15 (mol / mol) or more, more preferably 0.2 (mol / mol) or more, and usually 0.7 (mol / mol) or less, preferably 0.65 (mol / mol) or less, more preferably 0.6 (mol / mol) or less. is there. When the said ratio is low, the hardening reaction at the time of film forming will become slow, and as a result, it will become a heterogeneous ceramic porous body and may have a bad influence on abrasion resistance and water resistance. On the other hand, when the above ratio is high, the residual silanol groups in the ceramic porous body increase and it is easily affected by the external environment such as humidity during film formation, and a highly porous ceramic porous body is stably produced. It may not be possible.

  Further, from the viewpoint of higher heat and humidity resistance, other alkoxysilane compounds may be used. In that case, the ratio of silicon atoms derived from other alkoxysilanes to silicon atoms derived from all alkoxysilane compounds is usually 0.1 (mol / mol) or more, preferably 0.13 (mol / mol) or more, more preferably. Is 0.15 (mol / mol) or more, and usually 0.7 (mol / mol) or less, preferably 0.6 (mol / mol) or less, more preferably 0.55 (mol / mol) or less. It is. When the ratio is low, the resulting porous ceramic body is highly hydrophobic, but moisture confined in the porous structure by capillary force is not released from the inside of the film, which may cause deterioration of the film. is there. On the other hand, when the said ratio is high, the residual silanol group in a ceramic porous body will increase, and water resistance may fall too.

Here, the silicon atoms derived from all alkoxysilane compounds are alkoxysilane groups having 3 to 12 carbon atoms, tetraalkoxysilane groups, other alkoxysilane groups, and parts thereof contained in the ceramic composition. The total number of silicon atoms in the condensate.
Moreover, the silicon atom derived from tetraalkoxysilanes means the number of silicon atoms contained in the tetraalkoxysilane group contained in the composition and the tetraalkoxysilanes group among silicon atoms contained in the partial condensate containing the tetraalkoxysilane group. And the total number of silicon atoms belonging to the partial structure corresponding to. Therefore, even if the ceramic composition contains a compound having a silicon atom in addition to the alkoxysilane compound, the silicon atom that the compound has does not participate in the calculation of the ratio. In addition, the ratio of the silicon atom derived from tetraalkoxysilanes with respect to the silicon atom derived from all the alkoxysilane compounds can be measured by Si-NMR.

  The compound containing silicon (silicon atom-containing compound) in the ceramic composition is usually 0.05% by weight or more, preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and further preferably 1%. It is preferably contained in an amount of not less than 70% by weight, and is usually 70% by weight or less, preferably not more than 50% by weight, more preferably not more than 40% by weight, still more preferably not more than 20% by weight. If it is less than 0.05% by weight, the film-forming property of the ceramic composition when sprayed in the form of a mist may be lowered, and if it exceeds 70% by weight, the surface property of the ceramic precursor may be lowered. Specific examples of the silicon atom-containing compound include the aforementioned alkoxysilane groups having a C 3-12 alkyl group, tetraalkoxysilane groups, other alkoxysilane groups, and specific partial condensates.

In addition, from the viewpoint of controlling the film thickness of the obtained ceramic porous body, the solid content concentration containing the silicon atom-containing compound and the surfactant described below is usually 0.01% by weight or more, preferably 0.8%. 1% by weight or more, more preferably 0.5% 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.

[Surfactant]
In the present invention, a surfactant is used in the ceramic composition to be used from the viewpoint of the dischargeability of the ceramic composition in the film forming step, the film forming property of the ceramic precursor, and the low refractive index of the resulting ceramic porous body. Containing. The surfactant refers to a molecule having a lipophilic group (low polarity) and a hydrophilic group (high polarity). As the surfactant, any known surfactant can be used as long as the compound meets the above definition. Examples thereof include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, anionic surfactants and cationic surfactants are preferable from the viewpoint of dischargeability of the ceramic composition and film-forming properties of the ceramic precursor, and nonionic systems are preferable from the viewpoint of lowering the refractive index of the ceramic porous body. A surfactant is preferred. Further, among nonionic surfactants, a higher molecular weight is preferred. Specifically, the weight average molecular weight is usually 200 or more, preferably 1,000 or more, more preferably 3,000 or more, and particularly preferably 5,000 or more.

If the weight average molecular weight is too small, it may be difficult to maintain high porosity of the resulting ceramic porous body. In addition, although there is no restriction | limiting in the upper limit of the said 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 dischargeability of the ceramic composition may be reduced.
In addition, since it has an ethylene oxide part in a nonionic surfactant, it becomes stable with respect to the hydrolyzate or condensate of the alkoxysilane compound formed during the sol-gel reaction of the alkoxysilane compound.

Further, the main chain skeleton structure of the nonionic surfactant is not particularly limited. Specific examples of the main chain skeleton structure include polyether, polyester, polyol, polyurethane, polyolefin, polycarbonate, polydiene, polyvinyl ether, polystyrene, and derivatives thereof. Among these, a polymer containing a polyether as a constituent component is preferable. Specific examples thereof include polyethylene glycol (hereinafter referred to as “PEG” as appropriate), polypropylene glycol, polyisobutylene glycol, and the like. Among these, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer and / or polyethylene glycol are particularly preferable.
In addition, the said nonionic surfactant may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

From the viewpoint of improving the film forming property, a small amount of the following compounds may be added as a surfactant. Moreover, there is no restriction | limiting in particular in the combination and ratio, It can adjust arbitrarily.
For example, in addition to the surfactants described above, a fluorosurfactant having a lipophilic group as a fluorocarbon group, a silicone surfactant having a siloxane chain as the lipophilic group, and a surfactant having an alkyl group as the lipophilic group It is preferable that at least two types are selected from the agents, among others, the combination of a nonionic surfactant and a fluorosurfactant (especially those containing a perfluoroalkyl group), and a nonionic surfactant It is preferably selected from a combination of an agent and a silicone-based surfactant (particularly one containing a siloxane bond).

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.).
Moreover, as a ratio of the surfactant with respect to silicon atoms derived from all alkoxysilane compounds, from the viewpoint of surface properties of the obtained ceramic porous body, it is usually 0.001 (mol / mol) or more, preferably 0.002 (mol / mol) 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) or less.

[Organic solvent]
Although it does not specifically limit to the organic solvent used for the manufacturing method of the ceramic porous body of this invention, If an example of a suitable organic solvent is given, methanol, ethanol, n-propanol, isopropanol, 2-methyl-1- propanol, 1 Alcohols such as monohydric alcohols having 1 to 4 carbon atoms such as butanol, 2-butanol, t-butanol and 1-pentanol, dihydric alcohols having 1 to 4 carbon atoms, polyhydric alcohols such as glycerin and pentaerythritol The above-mentioned alcohols such as methyl acetate, ethyl acetate, isobutyl acetate, diethylene glycol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, 2-ethoxyethanol, propylene glycol monomethyl ether, propylene glycol methyl ether acetate, etc. Ethers or esterified products of ketones; 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-acetyl Amides such as pyrrolidine, N, N′-diformylpiperazine, N, N′-diformylpiperazine, N, N′-diacetylpiperazine; lactones such as γ-butyrolactone; tetramethylurea, N, N′-dimethyl Imidazolidine etc. Ureas; and dimethyl sulfoxide. Two or more of these may be selected and used.

  In the application step of the ceramic composition used in the present invention, it is preferable to use a lower alcohol having 1 to 3 carbon atoms in order to obtain a more stable liquid property. The lower alcohol easily interacts with the hydrolyzate and has a carbon number of 3 or less, so that the hydrolysis reaction of the hydrolyzate in the vicinity of the film surface that occurs during the formation of the ceramic precursor occurs moderately. The structural change of can be suppressed.

  Furthermore, in order to form a homogeneous precursor on the substrate, it is preferable to contain a high-boiling organic solvent having a boiling point of 100 to 180 ° C. in order to control the drying after coating and the condensation reaction that takes place. By containing a predetermined boiling point in the composition, it is sprayed in the form of a mist to prevent drying during the formation of the ceramic precursor on the substrate, and the hydrolyzate of the alkoxysilane compound contained in the composition Can suppress the condensation reaction by the interaction with the lower alcohol, thereby forming a stable and homogeneous ceramic precursor.

  More preferably, it is 110 to 170 degreeC, More preferably, it is 115 to 165 degreeC, Most preferably, it is 120 to 160 degreeC. When the temperature is lower than 100 ° C., it is sprayed in the form of a mist, and drying during the formation of the ceramic precursor on the substrate is fast, and the film surface may be roughened due to the shape of the atomized particles. On the other hand, when the temperature exceeds 180 ° C., the condensation reaction of the alkoxysilane compound in the removal of the organic solvent proceeds excessively, so that there is a possibility that film defects or vacancies collapse.

Among them, from the viewpoint of interaction with the hydrolyzate of alkoxysilane compound, as high boiling point solvents, 3-methyl-1-butanol, 1-pentanol, propylene glycol methyl ether acetate, glycerin, diethylene glycol dimethyl ether, triethylene glycol, etc. preferable. The molecular weight of the organic solvent is not particularly limited as long as the effect of the present invention is not significantly impaired, but is usually preferably 100 to 500, more preferably 110 to 400, further preferably 115 to 350, and most preferably 120 to 300. is there. If it is less than 100, on the other hand, if it exceeds 500, the steric size occupied by the organic solvent in the gel structure formed by the alkoxysilane compound is large, so that the distortion of the ceramic porous body after removal may increase.

  Moreover, the usage-amount of a high boiling point organic solvent is arbitrary unless the effect of this invention is impaired remarkably. However, with respect to the lower alcohol, usually 0.1 mol / mol or more, particularly 0.5 mol / mol or more, particularly 1 mol / mol or more is preferable, and usually 50 mol / mol or less, especially 30 mol / mol or less, particularly 25 mol. / Mol or less is preferable. If the amount of the organic solvent used is too small, the surface property of the ceramic porous body may be lowered, and if it is too large, the film quality of the ceramic precursor may be easily influenced by the surface energy of the substrate.

  Although it will not restrict | limit especially if it has the capability to mix the alkoxysilane compound mentioned above and water, From a compatible viewpoint with an alkoxysilane compound, methanol, ethanol, 1-propanol, t-butanol, 2-propanol, 2-Methyl-1-propanol, 1-butanol, 1-pentanol, ethyl acetate, methyl acetate, isobutyl acetate and the like are preferable.

[water]
The ceramic composition contains water. The purity of the water used is preferably higher. Usually, water subjected to either or both of ion exchange and distillation may be used. However, when the obtained ceramic porous body is used in an application field that particularly dislikes micro-impurities such as laminates for optical applications, a higher-purity ceramic porous body is desirable. It is preferable to use ultrapure water. Specifically, for example, water that has 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 derived from all alkoxysilane compounds is usually 10 (mol / mol) or more, preferably 11 (mol / mol) or more, more preferably 12 (mol / mol) or more. To do. If the ratio of water to silicon atoms derived from all alkoxysilane compounds is smaller than the above range, it is difficult to control the sol-gel reaction, and the surface properties of the ceramic precursor obtained by spraying the ceramic composition in a mist form deteriorate. Tend to impair transparency. The amount of water can be calculated by the Karl Fischer method (coulometric titration method).

[catalyst]
The ceramic composition may contain a catalyst. For example, a substance that promotes the hydrolysis and dehydration condensation reaction of the alkoxysilane compound 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, particularly 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 times or less, particularly 0.5 mol times or less with respect to the alkoxysilane compound. Is preferably 0.1 mol times or less. If the amount of the catalyst used is too small, the hydrolysis reaction will not proceed moderately, and active groups such as silanol groups are likely to remain in the ceramic porous body after production, which may reduce the water resistance of the ceramic porous body. If the amount is too large, it becomes difficult to control the reaction, and the catalyst concentration is further increased during production, so that the surface property of the ceramic porous body may be lowered.
Moreover, it is preferable that pH of a composition is 5.5 or less from a viewpoint of film forming property. More preferably, it is 4.5 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 simultaneously performed during film formation, and the film forming property tends to be further improved.

[Others]
The ceramic composition used in the present invention may contain components other than the alkoxysilane compound, organic solvent, surfactant, water, and catalyst 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.
Hereafter, the manufacturing method of the ceramic porous body of this invention is demonstrated in detail.

(Preparation of ceramic composition)
The ceramic 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, to more industrially prepare the ceramic composition, it is preferable to mix in the following manner. That is, an alkoxysilane compound, water and an organic solvent are mixed, and the mixture is aged to cause hydrolysis and dehydration polycondensation of the alkoxysilane compound to some extent. Then, a ceramic composition is prepared by mixing a surfactant with the mixture. Thereby, the affinity between the alkoxysilane compound and the surfactant can be maintained under sol-gel reaction conditions. The aging may be performed after mixing the mixture and the surfactant.

During the ripening, heating is preferably performed in order to advance hydrolysis / dehydration polycondensation reaction of the alkoxysilane compound. The heating condition is not particularly limited as long as the boiling point of the solvent to be used is not exceeded, but it is usually 28 ° C. or higher, preferably 30 ° C. or higher, particularly 45 ° C. or higher. If the heating temperature is too low, the reaction time becomes extremely long, and the productivity may decrease. On the other hand, the upper limit of the heating temperature is preferably 120 ° C. or lower, and more preferably 110 ° C. or lower. If it exceeds 120 ° C., the organic solvent and water in the composition will boil, and the decomposition / dehydration polycondensation reaction 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, and usually 10 hours or less, preferably 8 hours or less, more preferably 5 hours or less. It is. If the aging time is too short, it may be difficult to carry out the reaction uniformly, and if it is too long, the volatilization of the solvent cannot be ignored, and the composition ratio may change to lower the stability of the ceramic composition. .

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), which may change the composition ratio and lower the stability of the ceramic composition.
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 ceramic composition can be reduced, and it becomes possible to maintain the pot life of a ceramic composition long. Further, from the viewpoint of yield in the production of the ceramic porous body, it is preferable to perform aging without heating. Aging without heating may be performed after the preparation of the ceramic composition.

[Method for producing ceramic porous body]
[Film forming process]
A film forming step for forming a film of the ceramic composition used in the present invention is performed. In the film forming step, the ceramic composition used in the present invention is usually formed on the surface of a predetermined substrate to form the ceramic porous body of the present invention. There is no limitation on the film forming method, but, for example, a casting method in which the ceramic composition is extended onto the substrate using a bar coater, applicator, doctor blade, etc .; a dip coating method in which the substrate is immersed in the ceramic composition and pulled up Known examples include spin coating, capillary coating, die coating, and spray coating. Among these methods, a casting method, a die coating method, a dip coating method, a spray coating method, and a spin coating method are preferably employed because the ceramic composition can be uniformly applied. Among these, spin coating, dip coating, and spray coating are particularly preferable for forming a homogeneous film.

  When the ceramic composition is formed into a film by the casting method, the casting speed is not limited, but is usually 0.1 m / min or more, preferably 0.5 m / min or more, more preferably 1 m / min or more, and usually 1000 m / min or less, preferably 700 m / min or less, more preferably 500 m / min or less. If the casting speed is too slow, the film thickness may be uneven, and if it is too fast, it may be difficult to control the wettability with the substrate.

  In the dip coating method, the substrate may be dipped in the coating solution and pulled up at an arbitrary speed. The pulling speed at this time is not limited, but is usually 0.01 mm / second or more, preferably 0.05 mm / second or more, more preferably 0.1 mm / second or more, and usually 50 mm / second or less, preferably 30 mm / second. Second or less, more preferably 20 mm / second or less. If the pulling speed is too slow or too fast, the film thickness may be uneven. On the other hand, although there is no restriction | limiting in the speed | rate which immerses a base material in a coating liquid, Usually, it is preferable to immerse a base material in a coating liquid at a speed | rate comparable as a raising speed. Further, the immersion may be continued for an appropriate time from when the substrate is immersed in the coating solution until it is pulled up. There is no limitation on the duration of this immersion, but it is usually 1 second or more, preferably 3 seconds or more, more preferably 5 seconds or more, and usually 48 hours or less, preferably 24 hours or less, more preferably 12 hours or less. is there. If this time is too short, the adhesion to the substrate may be low, and if it is too long, a porous body may be formed during immersion and the smoothness may be low.

Furthermore, when the ceramic composition is formed by spin coating, the rotational speed is usually 1
0 revolutions / minute or more, preferably 50 revolutions / minute or more, more preferably 100 revolutions / minute or more, and usually 100,000 revolutions / minute or less, preferably 50000 revolutions / minute or less, more preferably 10,000 revolutions / minute or less. . If the rotational speed is too slow, the film thickness may be uneven. If the rotational speed is too fast, the vaporization of the solvent tends to proceed and the reaction such as hydrolysis of alkoxysilanes does not proceed sufficiently and the water resistance may be low.

  In addition, when the ceramic composition is applied and formed by the spray coating method, the method of the spray nozzle is not particularly limited, but may be selected in consideration of the advantages of each spray nozzle. Typical examples include a two-fluid spray nozzle (two-fluid atomization method), an ultrasonic spray nozzle (ultrasonic atomization method), a rotary spray nozzle (rotary atomization method), and the like. An ultrasonic spray nozzle and a rotary spray nozzle are preferable in that the atomization of the composition and the conveyance of the atomized particles to the substrate by the gas flow can be controlled independently. From the viewpoint of maintaining the liquidity of the composition, two fluids are preferable. A spray nozzle is preferred. Furthermore, the air velocity of the gas flow used for transporting the atomized particles is preferably adjusted as appropriate depending on the composition used, but is usually 5 m / sec or less, preferably 4 m / sec or less, more preferably 3 m / sec or less. is there. If the air velocity is too high, the membrane can become inhomogeneous. The gas used is not particularly limited, but an inert gas such as nitrogen is preferable. The distance between the spray nozzle and the substrate is preferably adjusted as appropriate according to the substrate size, but is usually 5 cm or more, preferably 10 cm or more, more preferably 15 cm or more. Moreover, it is 100 cm or less normally, Preferably it is 80 cm or less, More preferably, it is 50 cm or less. If this range is exceeded, film thickness unevenness may occur.

  However, in the film forming step, the relative humidity is usually 20% or more, preferably 25% or more, more preferably 30% or more, and usually 85% or less, preferably 80% or less, more preferably 75% or less. In this case, the film is formed. By setting the relative humidity in the film forming step within the above range, a film having high surface smoothness can be obtained. There is no restriction | limiting in the atmosphere in a film-forming process. For example, film formation may be performed in an air atmosphere, or film formation may be performed in an inert atmosphere such as argon.

  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 20 degreeC or more, Usually, 100 degreeC or less, Preferably it is 80 degreeC or less, More preferably, it is 70 degreeC. Hereinafter, it is more preferably 60 ° C. or less, particularly preferably 50 ° C. or less, particularly preferably 40 ° C. or less. If the temperature at the time of film formation is too low, the solvent is difficult to evaporate and the surface smoothness of the film may be reduced. If it is too high, the curing of alkoxysilanes may proceed rapidly and the film distortion may increase. .

  Although there is no restriction | limiting in the pressure at the time of performing a film-forming process, Usually, 0.05 Mpa or more, Preferably it is 0.08 Mpa or more, More preferably, it is 0.1 Mpa or more, Usually, 0.3 Mpa or less, Preferably it is 0.2 Mpa or less, More preferably, it is 0.15 MPa or less. If the pressure is too low, the solvent tends to evaporate and the leveling effect after film formation cannot be obtained, and the smoothness of the film may be reduced. If it is too high, the solvent is less likely to evaporate and the surface property of the film may be reduced. There is sex.

  By the way, in the dip coating method, the spin coating method, the spray coating method, the die coating method, the gravure printing method, and the screen printing method, there is a difference in drying speed, and a slight difference may occur in the stable structure of the film immediately after film formation. . This can be adjusted by changing the atmosphere during film formation. In addition, the slight difference in the stable structure of the film can be dealt with by surface treatment of the substrate.

Prior to film formation of the ceramic composition on the substrate, the substrate may be subjected to a surface treatment from the viewpoint of wettability of the ceramic composition and adhesion of the formed ceramic porous body. Good. Examples of such surface treatment include silane coupling treatment, anchor coat 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.

The film forming step may be performed once, but may be performed in two or more steps. For example, if the film forming step is performed twice or more through a heating step described later, it is possible to form a ceramic porous body having a laminated structure. This is useful, for example, when it is desired to stack layers having different refractive indexes.
After the ceramic composition is formed on the substrate, a rough drying step may be performed.

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 heat drying is performed, the temperature is usually 25 ° C. or higher, preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and usually 300 ° C. or lower, preferably 230 ° C. or lower, more preferably 200 ° C. or lower. desirable. 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, it is usually desirable to be about 60% RH or less, preferably 30% RH or less at normal pressure, or a vacuum state (humidity 0% RH) in order to prevent moisture absorption of the ceramic precursor. ) Is desirable.

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 ceramic precursor. However, it is usually preferable to have a clean atmosphere.
The rough drying time is not limited, and any organic solvent or water in the ceramic precursor can be removed, but conditions such as temperature, pressure, and humidity during rough drying, and the boiling point of the organic solvent contained in the ceramic composition It is preferable to determine in consideration of the process speed, characteristics of the ceramic precursor, and the like. The range is usually 1 second or longer, preferably 30 seconds or longer, more preferably 1 minute or longer, and usually 100 hours or shorter, preferably 24 hours or shorter, more preferably 3 hours or shorter.

[Heating process]
A ceramic porous body can be obtained by heating the ceramic precursor obtained in the film forming step. The heating conditions can be adjusted depending on the type of substrate and the organic solvent used in the composition, and are not particularly limited.
Durability and optical functions useful for optical applications can be exhibited by the progress of the adhesion to the base material, the smoothness of the film surface, the porous structure of the film structure and its stabilization through the heating process.

  The heating method is not particularly limited. For example, a translucent substrate is placed in a heating furnace (baking furnace) to heat the ceramic precursor, and the translucent substrate is mounted on a plate (hot plate). Then, a hot plate method in which the ceramic precursor is heated through the plate, a heater is disposed on the upper surface side and / or the lower surface side of the translucent base material, and electromagnetic waves (for example, infrared rays) are irradiated from the heater to make ceramic Examples include a method of heating the precursor.

  There is no limitation on the heating temperature, and any heating is possible as long as the ceramic precursor can be cured to form a ceramic porous body, but it is usually 90 ° C. or higher, preferably 120 ° C. or higher, more preferably 200 ° C. or higher. Preferably it is 350 degreeC or more, and is 750 degrees C or less normally, Preferably it is 600 degrees C or less, More preferably, it is 500 degrees C or less. When the heating temperature is too low, a large amount of the surfactant contained in the composition remains in the film, which may cause coloring and a decrease in durability. On the other hand, if the heating temperature is too high, the bonding between the translucent base material and the porous ceramic body is lost, and there is a possibility that the durability is reduced as described above.

  The heating rate during heating is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 ° C./min or more, preferably 10 ° C./min or more, and usually 500 ° C./min or less, preferably 300 The temperature is raised at a temperature of ℃ / min or less. If the rate of temperature rise is too slow, the ceramic porous body becomes dense and the refractive index is difficult to be lowered. If the rate of temperature rise is too fast, film distortion increases and may cause local cracks.

  The heating time is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 30 seconds or more, preferably 1 minute or more, more preferably 2 minutes or more, and usually 5 hours or less, preferably 2 hours or less, More preferably, it is 1 hour or less. If the heating time is too short, the unnecessary surfactant may not be removed, and sufficient optical performance may not be exhibited. On the other hand, if the heating time is too long, the reaction of the alkoxysilane compound proceeds and adhesion to the light-transmitting substrate is low. There is a possibility.

The pressure at the time of heating 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 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 vaporization of the organic solvent proceeds more than the reaction of the alkoxysilane compound, and the ceramic porous body having high hygroscopicity is likely to be obtained, and there is a possibility that a stable optical function cannot be maintained with respect to the external environment.

The atmosphere during heating is arbitrary as long as the effects of the present invention are not significantly impaired. Among them, an environment in which drying unevenness is unlikely to occur is preferable. It is particularly preferable to perform heating in an air atmosphere. It is also possible to perform an inert gas treatment and dry in an inert atmosphere.
As described above, the ceramic porous body can be obtained by performing the heat treatment, but it is also possible to carry out a cooling step, a post-treatment step, and the like as necessary after the heating step.

[Cooling process]
A cooling process is a process of cooling the ceramic porous body which became high temperature by the heating process. At this time, the cooling rate is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1 ° C./min or more, preferably 0.5 ° C./min or more, more preferably 0.8 ° C./min or more, More preferably, it is 1 ° C./min or more, usually 100 ° C./min or less, preferably 50 ° C./min or less, more preferably 30 ° C./min or less, still more preferably 20 ° C./min or less. If the cooling rate is too slow, the production cost may increase, and if it is too fast, it may cause local cracks.
The atmosphere in the cooling step is arbitrary as long as the effects of the present invention are not significantly impaired, and may be, for example, a vacuum environment or an inert gas environment. Furthermore, although there is no restriction | limiting in temperature and humidity, Usually, it is preferable to cool at normal temperature and normal humidity.

[Post-processing process]
Although there is no restriction | limiting in the specific operation performed at a post-processing process, For example, the surface of a ceramic porous body can be made more excellent in functionality by processing the obtained ceramic porous body with a silylating agent. . As a specific example, by treating with a silylating agent, hydrophobicity is imparted to the ceramic porous body, and contamination of the membrane surface and pores in the membrane can be prevented.

  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 ceramic porous body, immersing the ceramic porous body in the silylating agent, or placing the ceramic porous body in the vapor of the silylating agent. It can be done by exposing.
Further, as another example of the post-treatment, the ceramic porous body of the present invention can be aged under high humidity conditions to reduce unreacted silanol present in the porous structure. It is also possible to improve the water resistance of the body. Furthermore, it is possible to improve mechanical strength and alkali resistance by forming another inorganic oxide film on the ceramic porous body.

[Example 1]
[Preparation of ceramic composition]
Tetraethoxysilane (hereinafter TEOS) 1.86 g, Methyltriethoxysilane (MTES) 0.64 g, Ethanol (boiling point 78.3 ° C.) 0.58 g, Water 1.39 g and 0.3 wt% hydrochloric acid 3.25 g of an aqueous solution was mixed and stirred for 30 minutes in a water bath. Next, 1.33 g of hexyltrimethoxysilane (KBM-3063 made by Shin-Etsu Silicone) was added and mixed, and stirred in a water bath for 30 minutes. The mixture was further stirred at room temperature for 30 minutes to obtain a mixture (A).

  Next, as a surfactant, 1.54 g of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer (manufactured by ALDRICH, weight average molecular weight 5650, ratio of ethylene oxide moiety 30% by weight; hereinafter referred to as “P123” as appropriate) and ethanol By adding the mixture (A) to the mixed solution (B) mixed with 0.80 g, stirring at room temperature for 60 minutes, and filtering with a 0.45 μm filter (Whatman Japan Co., Ltd.). Mixture (C) was prepared.

11.37 g of this mixture (C) and 45.49 g 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 ceramic composition.
The ratio (mol / mol) of silicon atoms derived from alkoxysilanes having an alkyl group having 3 to 6 carbon atoms to silicon atoms derived from all alkoxysilanes in this ceramic composition is 0.3, and derived from all alkoxysilanes. The ratio (mol / mol) of silicon atoms derived from other alkylalkoxysilanes (methyltriethoxysilane) to silicon atoms is 0.2.

[Film forming process]
Using the obtained composition as a base material, a large slide glass (S112 manufactured by Matsunami Glass Industrial Co., Ltd., thickness: 1 mm) was used and applied 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.
[Heating process]
Next, it is placed in an oven set at 450 ° C. and heated in an air atmosphere for 2 minutes, so that the ceramic porous body having a good appearance on the base material (film thickness is 110 to 160 nm, surface roughness Ra is 3 nm or less) )

<< Minimum reflectance and refractive index calculation >>
As a result of measuring the reflectance with a spectral film thickness meter (FE-3000 manufactured by Otsuka Electronics Co., Ltd.), the minimum reflectance of the ceramic porous body obtained on the substrate is 0.48%, and the wavelength at that time is 507 nm. there were. The refractive index calculated using the Fresnel equation was 1.29.
《Abrasion test》
The cheese cloth described in Mil-Spec MIL-CCC-c-440 was reciprocated 20 times on the surface of the porous silica film obtained at a load of 500 g / cm ² . Abrasion evaluation is ◎ for “no scratches can be confirmed on the surface”, ○ for “no noticeable scratches and scratches not reaching the substrate”, “no scratches and no scratches on the substrate” "" In Example 1, no scratches could be confirmed on the surface.

《Haze, total light transmittance》
The haze and total light transmittance were measured with a haze meter (TM Double Beam Automatic Haze Computer HZ-2 manufactured by Suga Test Instruments Co., Ltd.). The haze of the obtained laminate was 0.43%, and the total light transmittance was 93.5%.
[Example 2]
Except that MTES 0.64 g, hexyltrimethoxysilane 1.33 g, and 1-butanol 45.49 g were changed to MTES 0.80 g, hexyltrimethoxysilane 1.11 g, and 1-butanol 45.24 g, the same as Example 1. Thus, a ceramic composition was obtained.

The ratio (mol / mol) of silicon atoms derived from alkylalkoxysilanes having 3 to 6 carbon atoms to silicon atoms derived from all alkoxysilanes in the ceramic composition is 0.25, based on silicon atoms derived from all alkoxysilanes. The ratio (mol / mol) of silicon atoms derived from other alkylalkoxysilanes (methyltriethoxysilane) is 0.25.
[Film forming step] and [Heating step] were performed in the same manner as in Example 1 to obtain a porous ceramic body having a good appearance (film thickness: 110 to 160 nm, surface roughness Ra: 3 nm or less) on the substrate.

<< Minimum reflectance, refractive index >>, << Abrasion test >>, << Haze, Total light transmittance >> were also measured and calculated in the same manner as in Example 1. The results are shown in Table 1.
[Example 3]
MTES 0.64g, hexyltrimethoxysilane 1.33g, P123 1.54g, 1-butanol 45.49g changed to MTES 0.48g, hexyltrimethoxysilane 1.55g, P123 1.61g, 1-butanol 46.06g A ceramic composition was obtained in the same manner as in Example 1 except that.

The ratio (mol / mol) of silicon atoms derived from alkylalkoxysilanes having 3 to 6 carbon atoms to silicon atoms derived from all alkoxysilanes in the ceramic composition is 0.35, relative to silicon atoms derived from all alkoxysilanes. The ratio (mol / mol) of silicon atoms (methyltriethoxysilane) derived from other alkylalkoxysilanes is 0.15.
[Film forming step] and [Heating step] were performed in the same manner as in Example 1 to obtain a porous ceramic body having a good appearance (film thickness: 110 to 160 nm, surface roughness Ra: 3 nm or less) on the substrate.

<< Minimum reflectance, refractive index >>, << Abrasion test >>, << Haze, Total light transmittance >> were also measured and calculated in the same manner as in Example 1. The results are shown in Table 1.
[Example 4]
TEOS 1.86 g, MTES 0.64 g, hexyltrimethoxysilane 1.33 g, P123 1.54 g, 1-butanol 45.49 g, TEOS 1.30 g, MTES 1.59 g, hexyltrimethoxysilane 0.66 g, P1231.56 g, 1 -A ceramic composition was obtained in the same manner as in Example 1 except that the amount was changed to 44.54 g.

The ratio (mol / mol) of silicon atoms derived from alkyl alkoxysilanes having 3 to 6 carbon atoms to silicon atoms derived from all alkoxysilanes in the ceramic composition was 0.15, and relative to silicon atoms derived from all alkoxysilanes. The ratio (mol / mol) of silicon atoms (methyltriethoxysilane) derived from other alkylalkoxysilanes is 0.5.
[Film forming step] and [Heating step] were performed in the same manner as in Example 1 to obtain a porous ceramic body having a good appearance (film thickness: 110 to 160 nm, surface roughness Ra: 3 nm or less) on the substrate.

<< Minimum reflectance, refractive index >>, << Abrasion test >>, << Haze, Total light transmittance >> were also measured and calculated in the same manner as in Example 1. The results are shown in Table 1.
[Example 5]
TEOS 1.86 g, MTES 0.64 g, hexyltrimethoxysilane 1.33 g, P123 1.54 g, 1-butanol 45.49 g, TEOS 1.12 g, MTES 1.59 g, hexyltrimethoxysilane 0.89 g, P123 1.56 g The ceramic composition was changed in the same manner as in Example 1 except that the heating time in the water bath was changed from 30 minutes to 2 hours after the addition of hexyltrimethoxysilane to 44.68 g of 1-butanol. Obtained.

The ratio (mol / mol) of silicon atoms derived from alkyl alkoxysilanes having 3 to 6 carbon atoms to silicon atoms derived from all alkoxysilanes in the ceramic composition is 0.2, and relative to silicon atoms derived from all alkoxysilanes. The ratio (mol / mol) of silicon atoms (methyltriethoxysilane) derived from other alkylalkoxysilanes is 0.5.
[Film forming step] and [Heating step] were performed in the same manner as in Example 1 to obtain a porous ceramic body having a good appearance (film thickness: 110 to 160 nm, surface roughness Ra: 3 nm or less) on the substrate.

<< Minimum reflectance, refractive index >>, << Abrasion test >>, << Haze, Total light transmittance >> were also measured and calculated in the same manner as in Example 1. The results are shown in Table 1.
[Example 6]
MTES 0.64g, 1-butanol 45.49g was changed to MTES 1.11g, 1-butanol 44.89g, and hexyltrimethoxysilane 1.33g was changed to decyltrimethoxysilane (Shin-Etsu Chemical KBM3103C) 0.70g. A ceramic composition was obtained in the same manner as in Example 1 except that.

The ratio (mol / mol) of silicon atoms derived from alkyl alkoxysilanes having 3 to 6 carbon atoms to silicon atoms derived from all alkoxysilanes in the ceramic composition was 0.15, and relative to silicon atoms derived from all alkoxysilanes. The ratio (mol / mol) of silicon atoms (methyltriethoxysilane) derived from other alkylalkoxysilanes is 0.35.
[Film forming step] and [Heating step] were performed in the same manner as in Example 1 to obtain a porous ceramic body having a good appearance (film thickness: 110 to 160 nm, surface roughness Ra: 3 nm or less) on the substrate.

<< Minimum reflectance, refractive index >>, << Abrasion test >>, << Haze, Total light transmittance >> were also measured and calculated in the same manner as in Example 1. The results are shown in Table 1.
[Example 7]
Except that MTES 0.64 g, decyltrimethoxysilane 0.70 g, and 1-butanol 45.49 g were changed to MTES 0.95 g, decyltrimethoxysilane 0.94 g, and 1-butanol 45.19 g, the same as in Example 6. A ceramic composition was obtained.

The ratio (mol / mol) of silicon atoms derived from alkyl alkoxysilanes having 3 to 6 carbon atoms to silicon atoms derived from all alkoxysilanes in the ceramic composition is 0.2, and relative to silicon atoms derived from all alkoxysilanes. The ratio (mol / mol) of silicon atoms (methyltriethoxysilane) derived from other alkylalkoxysilanes is 0.3.
[Film forming step] and [Heating step] were performed in the same manner as in Example 1 to obtain a porous ceramic body having a good appearance (film thickness: 110 to 160 nm, surface roughness Ra: 3 nm or less) on the substrate.

<< Minimum reflectance, refractive index >>, << Abrasion test >>, << Haze, Total light transmittance >> were also measured and calculated in the same manner as in Example 1. The results are shown in Table 1.
[Comparative Example 1]
TEOS 1.86 g, MTES 0.64 g, 1-butanol 45.49 g was changed to TEOS 1.70 g, MTES 1.73 g, 1-butanol 43.9 g, and hexyltrimethoxysilane (KBM3063 manufactured by Shin-Etsu Chemical Co., Ltd.) was not added. In the same manner as in Example 1, a ceramic composition was obtained.

The ratio (mol / mol) of silicon atoms derived from alkyl alkoxysilanes having 3 to 6 carbon atoms to silicon atoms derived from all alkoxysilanes in the ceramic composition is 0, and other ratios relative to silicon atoms derived from all alkoxysilanes are 0. The ratio (mol / mol) of silicon atoms (methyltriethoxysilane) derived from alkylalkoxysilanes is 0.5.
[Film forming step] and [Heating step] were performed in the same manner as in Example 1 to obtain a porous ceramic body having a good appearance (film thickness: 110 to 160 nm, surface roughness Ra: 3 nm or less) on the substrate.

<< Minimum reflectance, refractive index >>, << Abrasion test >>, << Haze, Total light transmittance >> were also measured and calculated in the same manner as in Example 1. The results are shown in Table 1.
[Comparative Example 2]
0.64 g of MTES was changed to 0.280 g of trimethylmethoxysilane (Toray Dow Z-6013), 1.33 g of hexyltrimethoxysilane was changed to 1.55 g, and 45.49 g of 1-butanol was changed to 45.14 g. A ceramic composition was obtained in the same manner as in Example 1 except that.

The ratio (mol / mol) of silicon atoms derived from alkylalkoxysilanes having 3 to 6 carbon atoms to silicon atoms derived from all alkoxysilanes in the ceramic composition is 0.35, relative to silicon atoms derived from all alkoxysilanes. The ratio (mol / mol) of silicon atoms (methyltriethoxysilane) derived from other alkylalkoxysilanes is 0.15.
[Film forming step] and [Heating step] were performed in the same manner as in Example 1 to obtain a porous ceramic body having a good appearance (film thickness: 110 to 160 nm, surface roughness Ra: 3 nm or less) on the substrate.

  << Minimum reflectance, refractive index >>, << Abrasion test >>, << Haze, Total light transmittance >> were also measured and calculated in the same manner as in Example 1. The results are shown in Table 1.

Claims (6)

  A porous ceramic body comprising an alkyl group having 3 to 12 carbon atoms and having a minimum surface reflectance of 1.5% or less.   2. The ceramic porous body according to claim 1, comprising a positive element containing silicon, wherein the silicon content is 50 mol% or more with respect to the content of the positive element.   A ceramic porous laminate comprising: a base material; and the ceramic porous body according to claim 1 or 2, which has a thickness of 0.05 to 3 µm and is provided on the base material.   The ceramic porous laminate according to claim 3, wherein Tg of the substrate is 200 ° C or lower.   An optical member comprising: a base material; and the ceramic porous body according to claim 1 or 2 provided on the base material.   An antireflection laminate comprising a base material and the ceramic porous body according to claim 1 or 2 provided on the base material.