JP6540158B2 - Porous laminate - Google Patents

Description

  The present invention relates to a laminate having a mesoporous layer, and more specifically, the mesoporous layer is a porous layer of silica, and at least one surface thereof is a layer of a polymer having specific properties. The present invention relates to a laminated body provided.

By having a space shorter than the wavelength of light inside the mesoporous body, the refractive index as the porous body can be made lower than that without the space inside.
For example, a mesoporous porous body using silica can be used as a transparent substance having a low refractive index because silica itself is transparent to visible light. Such a porous body that is transparent to visible light applies a mixture of a hydrolyzate of alkoxysilanes and an organic polymer, from one that applies and dries a dispersion of transparent particles (for example, Patent Document 1). It can be obtained by heating it to form a silica membrane and burning it into an organic polymer to make it a porous body (for example, Patent Document 2).

Such mesoporous bodies are often used in the form of thin films.
In particular, when the mesoporous body is provided on the surface of glass, the light coming from the side of the porous body is not reflected and is easily taken into the glass. On the other hand, for light from the glass side, use a film with a low refractive index such as a mesoporous body to increase the proportion of light that is totally reflected rather than using white or specular light for reflection. You can also.

  There are cases where it is intended to provide other parts etc. on the surface of the mesoporous body used to improve such optical characteristics. In such cases, it is usually conceivable to use the adhesive to adhere other substances. That is, a laminate of a mesoporous layer and an adhesive layer is made to be bonded to another.

JP 2004-258348 A JP, 2006-265530, A

  When it is intended to adhere other substances to the surface of the mesoporous body using an adhesive, the pores of the mesoporous layer are literally mesopores and the diameter is small, so that the adhesive has a high height. It was thought that the molecule did not penetrate deep into the membrane. However, when an adhesive layer is to be actually provided, the adhesive contained in the adhesive layer may penetrate into the pores of the mesoporous porous layer or roughen part of the mesoporous porous layer, resulting in an increase in refractive index. Created the problem of The problem is that the lower the refractive index of the mesoporous layer (the higher the percentage of pores), the higher the percentage of voids in the mesoporous layer, so that the adhesive tends to fill the inside of the holes, and the refractive index is higher. It raises the task of rising. In particular, in order to have high adhesive strength, many of the adhesives infiltrate into the unevenness of the adhesive surface and harden, or roughen and bite the surface to obtain a so-called anchor effect and increase adhesive strength. Therefore, it turned out that this tendency is intense.

In addition, since the adhesive which is so-called adhesive, which adheres without curing, is more likely to be deformed, as it is generally considered, rather than the adhesive which is adhered by the final curing. However, it was also found that, surprisingly, it did not enter into the mesopores and it was easy to maintain the optical properties of the mesoporous layer.
Also, the present inventors paid attention to the distribution of the pore diameter of the membrane of the porous layer. That is, in the inside surrounded by the matrix forming the porous layer and the surface released to the outside, the diameter of the pores is slightly different but the surface is larger, and the difference in diameter of the pores It has been found that even if there is a slight difference depending on the method of forming the porous layer, it is necessarily generated due to the structural difference between the surface and the inside.

  Therefore, as a result of intensive studies, the present inventors based on the above-mentioned findings, so that the adhesive penetrates only in the region where the pore diameter of the surface of the porous layer is expanded, and does not penetrate into the depth from there. It has been found that, by doing this, it is possible to obtain a laminate having both the adhesive strength and the low refractive index due to being porous. Then, that the adhesive penetrates only into the pore diameter expansion region of the porous layer to be combined means that the adhesive strength to the porous layer can be used as a standard, and the porous layer is only weak in adhesive strength. We have found that the shape of the reflection spectrum can be used to eliminate adhesives that would penetrate into the entire porous layer and reached the present invention. That is, by providing an adhesive layer exhibiting specific properties adjacent to the mesoporous layer, the mesoporous layer can maintain a low refractive index and fill the mesopores of the mesoporous layer in a large amount, for example A laminate having an adhesive layer in which the adhesive agent was retained only on the surface of the porous layer and in the vicinity thereof did not occur because the phenomenon of solidifying into the entire mesoporous layer did not occur.

  With regard to this principle, as described above, the matrix of the porous layer shrinks during drying or firing, but at this time the surface shrinks by the amount not pulled by the surrounding matrix, and as a result, pores near the surface An enlarged pore diameter area is created. The low refractive index obtained by the porous layer is that the adhesive penetrates only in the portion where the pore diameter is expanded and exerts the adhesive force while preventing the adhesive from penetrating below the pore diameter expanded region. It is thought that the rate and the convenience that other parts etc. can be stuck on this porous layer could be made to be compatible. Simply put, it is possible to determine whether or not the substrate is appropriately infiltrated into the substrate depending on whether or not the substrate exhibits adequate adhesion to the substrate, and only those having only weak adhesion. It is said that the values of the shift of the reflection spectrum before and after the endurance test can be used to eliminate it.

That is, the gist of the present invention resides in the following.
(1) A laminate comprising a mesoporous layer and an adjacent adhesive layer, wherein the adhesive layer has a peel strength measured at a peel rate of 30 mm / min in a 180 ° peel test of 0. It is a range of 05 N / 25 mm or more and 14 N / 25 mm or less, and the value of the shift of the reflection spectrum before and after the endurance test for 10 days at 80 ° C. and 50% RH is −30 nm or more and 200 nm or less body.

(2) The laminate according to (1), wherein the thickness of the adhesive layer is 5 μm or more and 100 μm or less.
(3) The laminate according to (1) or (2), wherein the polymer compound is an acrylic resin.
(4) The laminate according to any one of (1) to (3), wherein the porous layer is porous silica.
(5) The laminate according to any one of (1) to (4), wherein the refractive index of the porous layer is 1.30 or less.

  (6) The laminate according to any one of (1) to (5), wherein the porous layer is adjacent to another layer having a refractive index of 1.40 or more.

  According to the laminate of the present invention, other substances can be adhered to the surface while maintaining the low refractive index of the porous body layer.

FIG. 1 is a view used for explaining the calculation for determining the reflectance difference from the reflection spectrum of the base material-porous layer interface of the laminate of the present invention. FIG. 2 is a diagram used for explaining the calculation for determining the shift value (peak shift value) of the reflection spectrum from the reflection spectrum of the substrate-porous layer interface of the laminate before and after the environmental test of the present invention.

  Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be arbitrarily changed and implemented without departing from the scope of the present invention.

[Laminate]
The laminate of the present invention is a laminate comprising a mesoporous layer and an adjacent adhesive layer. Of course, another layer may be present adjacent to this laminate. Preferably, the mesoporous layer is adjacent to the layer having a refractive index of 1.40 or more, and more preferably, the layer is substantially composed of polyethylene resin, polyethylene terephthalate resin, acrylic resin, glass, etc. It is a non-colored transparent layer. By being transparent, application to optical devices such as displays and light guide plates for illumination can be expected. The layer adjacent to the most preferred mesoporous layer, opposite to the adhesive layer, is a layer of glass.

[Adhesive layer]
The adhesive layer used in the present invention is a layer having an adhesive ability, contains a polymer compound which is usually an adhesive, and has a peel strength of 0 at a peel rate of 30 mm / min in its 180 ° peel test. It is characterized in that it is in the range of .05 N / 25 mm or more and 14 N / 25 mm or less.

  In general, an adhesive is a liquid having high fluidity at the time of bonding, and is easily wetted to an adherend and then cured by a chemical reaction or heat, that is, it causes a state change of liquid → solid and strongly bonds at the interface . However, some of the adhesives, like pressure sensitive adhesives (adhesives in a narrow sense), are soft solids with flowability and cohesion, as they are, ie without state change, Some are wet and adhere to an adherend while remaining solid. However, even if such an adhesive is present adjacent to the porous layer as in the present invention, the adhesive having too high adhesion tends to be highly wettable and flowable, and is solid Although it is easily wetted to the inside of the pores of the porous layer, the refractive index of the porous layer is increased. Especially in high temperature environments, the tendency becomes remarkable. On the other hand, an adhesive having too low adhesive strength tends to have low fluidity, and is poor in flexibility, and peels off due to the difference in thermal expansion coefficient with the porous layer when the laminate is exposed to a high temperature environment, The porous layer may be broken (an adhesive having increased fluidity may penetrate into the resulting gap at high temperature) to increase the refractive index. In addition, when the flexibility of the adhesive layer is low, the adhesive layer absorbs the force or impact when a load or an impact force is horizontally applied to one of the interfaces bordering the adhesive layer-porous layer interface. In this case, the force applied to the interface or the porous layer is increased, and the interface or the porous layer may be destroyed.

However, when the adhesive layer having the above-mentioned characteristics is used, the reason is not clear, but for example, because it has appropriate wettability, flowability, and flexibility from the viewpoint of preventing intrusion into the porous layer. Even in a high temperature environment, the wetting and spreading of the adhesive layer remains near the outer surface of the porous membrane and / or the pore entrance. In addition, when the film is exposed to a high temperature environment, the film does not break due to the expansion (and the penetration and the increase in the refractive index).

  The lower limit of the peel strength may be any size that allows the material to be attached to be attached, but the lower limit is 0.05 N / 25 mm or more in order to function as an adhesive layer. Preferably, it is 1 N / 25 mm or more, more preferably 2 N / 25 mm or more. On the other hand, the upper limit is 14 N / 25 mm or less, more preferably 12 N / 25 mm or less, and most preferably 10 N / 25 mm or less. This peel strength is an essential condition for the adhesive to penetrate only into the above-mentioned pore expansion region with respect to various substrates.

Among polymer-based adhesives used for such adhesive layers, an adhesive that is generally referred to as a pressure-sensitive adhesive and that adheres without curing does not penetrate deep into the mesoporous pores. The optical properties of the porous layer are easily maintained.
The adhesive layer is preferably an acrylic resin, considering that the laminate of the present invention is used in expectation of an optical function. In addition, the acrylic resin has high affinity to the silica material which is a preferable material of the porous layer of the present invention, and is also preferable from the viewpoint of adhesion between the layers. The acrylic resin refers to a polymer of acrylic ester and / or methacrylic ester or a copolymer thereof.

(Acrylate ester)
There is no restriction in the kind of acrylic ester used for acrylic resin. Examples of suitable ones are methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, i-butyl acrylate, t-acrylate Butyl, n-pentyl acrylate, 1-methylbutyl acrylate, 1-ethylpropyl acrylate, 1,1-dimethylpropyl acrylate, 2-methylbutyl acrylate, 2-ethylpropyl acrylate, 2,2-dimethyl acrylate Propyl, 3-methylbutyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-heptyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, n-nonyl acrylate, n-decyl acrylate, acrylic acid n-undecyl, n-dodecyl acrylate, N-Tridecyl lactate, n-tetradecyl acrylate, n-pentadecyl acrylate, n-hexadecyl acrylate, n-heptadecyl acrylate, n-octadecyl acrylate, β-cyanoethyl acrylate, β-chloroethyl acrylate, acrylate Phenyl, benzyl acrylate and the like can be mentioned.

Among the above-mentioned acrylic esters, methyl acrylate, ethyl acrylate and butyl acrylate in order to balance the appropriate fluidity and wettability and to prevent the anisotropic expansion and contraction of the adhesive layer due to crystallization. And 2-ethylhexyl acrylate are more preferred.
(Methacrylic acid ester)
There is no restriction on the type of methacrylic acid ester used for the acrylic resin. Examples of suitable ones are methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, i-butyl methacrylate, t- methacrylate Butyl, n-pentyl methacrylate, 1-methylbutyl methacrylate, 1-ethylpropyl methacrylate, 1,1-dimethylpropyl methacrylate, 2-methylbutyl methacrylate, 2-ethylpropyl methacrylate, 2,2-dimethyl methacrylate Propyl, 3-methylbutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, n-nonyl methacrylate, n-decyl methacrylate, methacrylate Le acid n- undecyl methacrylate n- dodecyl, methacrylic acid n- tridecyl methacrylate n- tetradecyl methacrylate n- pentadecyl methacrylate n- hexadecyl methacrylate n- heptadecyl methacrylate n- octadecyl,
Examples thereof include β-cyanoethyl methacrylate, β-chloroethyl methacrylate, phenyl methacrylate, and benzyl methacrylate.

Among the above-mentioned methacrylic acid esters, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacrylic acid are also used to obtain appropriate fluidity and wettability, and to prevent anisotropic expansion and contraction of the adhesive layer due to crystallization. More preferred is 2-ethylhexyl acid.
(Preferred combination of acrylic acid ester and methacrylic acid ester)
When two or more kinds of acrylic acid ester and / or methacrylic acid ester are used in combination, from the viewpoint of balance of fluidity and cohesion, as the combination, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate etc. A combination of short ester alkyl groups with relatively long alkyl groups of esters such as butyl acrylate, hexyl acrylate and 2-ethylhexyl acrylate is preferred. Esters of alkyl groups having a carbon chain length of 1 to 3 are relatively low in fluidity, and therefore low in wettability. In addition, the crystallization tendency is small. On the other hand, an ester having a carbon chain length of about 4 to 8 of the alkyl group is relatively high in fluidity, and therefore high in wettability. That is, by controlling the mixing ratio of the two, more precise control of the flowability, ie, the wettability, becomes possible.

The fact that the adhesive layer is acrylic can be confirmed by infrared spectroscopy, ¹³ C-NMR or ¹ H-NMR spectrum measurement.
The thickness of the adhesive layer is preferably 0.1 μm or more, more preferably 1 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, still more preferably 300 μm or less, and most preferably 5 μm to 100 μm. If it is a film thickness of the said range, it will not be easily torn at the time of sticking, and sufficient transparency can be ensured. The thickness of the adhesive layer can be measured with a thickness gauge or the like.

On the other hand, from the viewpoint of maintaining the refractive index of the porous film, the thickness of the adhesive layer is preferably 3 μm or more, more preferably 5 μm or more, still more preferably 15 μm or more, and most preferably 20 μm or more.
By increasing the film thickness of the adhesive layer in this manner, the flowability of the adhesive contained in the adhesive layer can be sufficiently obtained, the flexibility can be enhanced accordingly, and a more excellent adhesive force can be obtained.
Similarly, from the viewpoint of improving the productivity of the porous film, the thickness of the adhesive layer is usually 600 μm or less, preferably 200 μm or less, more preferably 100 μm or less, particularly preferably 80 μm or less, most preferably 60 μm or less It is. Generally, in the case of an adhesive or a so-called adhesive, as the film thickness increases, the solvent tends to remain inside. In order to prevent this, drying for a long time is required. Therefore, by setting the film thickness to the upper limit value or less, the drying time can be shortened and the drying temperature can be lowered.

[Wavelength shift of reflection spectrum before and after environmental test]
In the present invention, the shift of the reflection spectrum before and after 10 days of endurance test (environmental test) at 80 ° C. and 50% RH is required to be −30 nm or more and 200 nm or less. The wavelength shift of the peak of this reflection spectrum will be described below.
The peak wavelength of the minimum reflectance peak of the reflection spectrum immediately after the formation of the adhesive layer changes between 400-1000 nm of the reflection spectrum immediately after forming the adhesive layer on the porous layer and after the endurance test (environmental test) If the shift width after the test is called “peak shift”, the case where the peak is shifted to a low wavelength after the test is taken as positive, and the shift to a high wavelength is taken as negative (eg before the endurance test (environmental test) If the minimum reflectance wavelength is 650 nm and its peak changes to 615 nm after environmental testing, peak shift = 650 nm-615 nm = +35 nm).

The peak wavelength of the reflection spectrum is related to the film thickness of the porous layer, and when the peak shift is positive, it means that the film thickness becomes thin, and when the value of the peak shift is negative, the film It means that the thickness has increased.
The peak shift in the range of −10 nm or more and +10 nm or less is the most preferable because it means that the porous layer hardly changes before and after the endurance test (environmental test).

  When the peak shift is positive, 200 nm or less is preferable, 150 nm or less is more preferable, 100 nm or less is more preferable, and 50 nm or less is still more preferable. In the vicinity of the interface on the opposite side of the base of the porous layer, the shrinkage rate at the time of firing is higher than that in the inside, so the vicinity of the surface of the porous layer, in particular the porous layer is made a layer (base) adjacent to glass etc. If provided, the opposite side, that is, the entrance of the pore in the vicinity of the interface with the adhesive layer and its vicinity are considered to have a pore diameter expanded region in which the pore diameter is somewhat expanded compared to the inside . When the peak shift is 200 nm or less, although the adhesive penetrates into the pore diameter expansion region in the vicinity of the inlet of the porous layer, it is considered that the penetration stops in the pore diameter expansion region. However, when a peak shift of more than 200 nm occurs, it means that penetration has occurred in the range beyond the pore diameter expansion region, and with such characteristics, the penetration stops. In addition, it is conceivable that they will completely infiltrate. Furthermore, if a peak shift of more than 200 nm occurs, the adhesive that has penetrated into the porous layer expands under an environment of 80 ° C., causing the porous layer to be greatly damaged or crushed. A crack is generated, and the adhesive penetrates from the adhesive layer to deteriorate the characteristics such as the refractive index.

  When the peak shift is negative, −30 nm or more is preferable, −20 nm or more is more preferable, and −10 nm or more is more preferable. When the peak shift is negative, particularly smaller than -30 nm, the film thickness is increased, but it is not conceivable that the inorganic porous film such as silica is expanded by heating at about 80 ° C., in this case, Although the reason is unknown, it is expected that some deterioration occurs in the film, for example, expansion of the adhesive that has penetrated into the pore diameter expansion region, so if it changes significantly in the negative direction from -30 nm, the high temperature There is a possibility that a constant quality can not be maintained during continuous use.

  On the other hand, it is preferable that the peak shift be 5 nm or more, more preferably 15 nm or more, and most preferably 30 nm or more, because the adhesive preferably penetrates into the above-mentioned pore diameter expanded region from the viewpoint of adhesive strength. is there. The upper limit is preferably 200 nm or less, more preferably 70 nm or less, and most preferably 60 nm or less. The peak shift by the endurance test (environmental test) means that the adhesive penetrates into the pore diameter expansion region of the porous membrane even after bonding, while the affinity with the surface of the porous membrane is It means that it is high, and as a result it can be expected to have the effect of enhancing the adhesive strength. Therefore, if the peak shift is within the above range, it is possible to expect the effect that the adhesion can be improved within the range suitable for the present invention and the low refractive index can be maintained. And by making peak shift into the said range, an adhesive agent does not spread easily also to the thickness direction of a porous layer, and the horizontal direction in a porous layer, and it is suitable also at the time of the use under high temperature.

[Porous layer]
In a more preferred embodiment of the present invention, the porous layer is substantially transparent to visible light, and specifically, the transmittance is preferably 90% or more. In the present invention, other substances can be adhered to the porous layer through the adhesive layer while maintaining the low refractive index of the porous layer.
As an element constituting the porous layer, the cation may contain other than silicon, but preferably the silicon in the cation is preferably 90 mol% or more, more preferably 95
The remainder is mol% or more, most preferably silicon alone, excluding unavoidable impurities and trace additives.

The refractive index of the porous layer is preferably 1.10 or more, more preferably 1.13 or more, and still more preferably 1.15 or more. As an upper limit, 1.30 or less is preferable, 1.27 or less is more preferable, and 1.23 or less is more preferable. It is preferable that the refractive index is 1.15 or more, because an adhesive layer satisfying the characteristics defined in the present invention can be provided relatively easily on the porous layer, and sufficient adhesion can be obtained. Further, when the refractive index is 1.30 or less, the refractive index is lower than that of glass, so that it is possible to obtain an optical effect (easiness of total reflection, refractive index difference of glass-porous layer interface) it can. On the other hand, when the lower limit of the refractive index is 1.10 or more, the force applied at the time of adhesion of the adhesive layer or when another layer is provided on the adhesive layer, withstands the load or the adhesive layer-porous due to temperature change The strength of the porous layer is not easily caused by the difference in the thermal expansion coefficient at the interface of the porous layer, and sufficient strength is easily obtained. It is preferable because it does not increase too much.

The thickness of the porous layer is preferably 50 nm or more in order to exert an optical effect, have a pore diameter expanded region, and obtain strength. On the other hand, the upper limit of the thickness is not particularly limited, but 1 mm or less is preferable as a range in which economical efficiency and uniform structure are easily uniformed.
Furthermore, from the viewpoint of the optical performance and peel strength of the laminate after the adhesive layer is provided, it is preferably 250 nm or more, more preferably 300 nm or more, and most preferably 500 nm or more. The upper limit is preferably 3 μm or less, more preferably 2 μm or less, and most preferably 1.2 μm. By setting the thickness to 250 nm or more, it is possible to prevent the influence of a very small amount of low molecular weight components and residual solvent in the adhesive layer, especially the increase of the refractive index, which is industrially preferable. In addition, since the porous layer is a layer for obtaining optical characteristics, it is preferable that the porous layer is equal to or less than the above-mentioned upper limit value from the point of being unnecessarily thick.

  The porous layer having such a pore diameter expanded region can be produced by various known methods for producing a mesoporous body, and is not particularly limited. There is no problem even in the type of simply applying and drying silica particles, because the pore diameter expanded region is formed by drying shrinkage, but more preferably, it has a heating step after drying, at which time heat of 180 ° C. or more is applied The porous layer is preferable because the pore diameter expanded region appears notably.

Hereinafter, an example of a method for producing silica porous will be described as an example of the mesoporous porous layer suitable for the present invention, but the mesoporous layer used in the present invention is particularly limited as long as it is a mesoporous layer. However, even if the material is silica, the manufacturing method is not limited to the following method.
In addition, a mesoporous means what is porous and whose inside pore is a pore of about 2-50 nm.

The layer (hereinafter sometimes referred to as "silica porous layer") made of a silica porous suitable as the mesoporous layer used in the present invention uses, for example, a composition containing alkoxysilane, water, and an organic solvent. Manufactured.
In order to produce the silica porous layer (hereinafter, sometimes referred to simply as "silica porous layer") used in the present invention, first, a composition as a raw material is prepared, formed into a film, and then heated. To obtain a porous silica layer.

Usually, a composition containing an alkoxysilane, water, an organic solvent, and, if necessary, an organic polymer as a template material is applied on a substrate (film forming step) to form a layer of a silica-based precursor film, as necessary The organic polymer extraction step is carried out to obtain a laminate having a porous silica layer.
In addition, in the production of the porous silica layer used in the present invention, other operations may be performed as necessary. That is, as long as the effects of the present invention are not significantly impaired, optional steps may be performed before, during, and after each step described below. For example, aging may be performed during or after preparation of the composition used for producing the porous silica membrane of the present invention, and cooling and post-treatment of the porous porous membrane of the present invention after curing may be performed.

{Composition used for producing the porous silica membrane of the present invention}
First, with respect to the composition used for producing the porous silica layer suitable for the present invention, its blending components and preparation method will be described.

<Alkoxysilane>
Examples of alkoxysilanes include tetraalkoxysilanes, monoalkyltrialkoxysilanes, dialkyldialkoxysilanes, trialkylalkoxysilanes, their hydrolysates and partial condensates (oligomers etc.) and the like.

  The alkoxysilane is preferably used in combination of two or more, and preferably contains a hydrolyzate and a partial condensate of these alkoxysilanes. By using two or more kinds of alkoxysilane in combination, there is an advantage that it is possible to control the strength and the refractive index of the formed silica skeleton by controlling the compounding ratio.

(Tetraalkoxysilane)
There is no restriction on the type of tetraalkoxysilane. Examples of suitable ones include tetramethoxysilane, tetraethoxysilane, tetra (n-propoxy) silane, tetraisopropoxysilane, tetra (n-butoxy) silane, tetra (t-butoxy) silane, tetra (n-pentoxy) And the like.) Silane, tetra (isopentoxy) silane and the like.

  From the viewpoint of the stability of the silica-based precursor film in the rough drying step described later, tetramethoxysilane and tetraethoxysilane and partial condensates thereof are preferable, and tetraethoxysilane is more preferable. However, since tetraalkoxysilane tends to cause hydrolysis and partial condensation over time, even when only tetraalkoxysilane is prepared, the hydrolyzate and partial condensate of the tetraalkoxysilane usually coexist with the tetraalkoxysilane There are many things.

(Monoalkyl trialkoxysilane)
There is no limitation on the type of monoalkyltrialkoxysilane. Examples of suitable ones are trimethoxysilane, triethoxysilane, tri-n-propoxysilane, triisopropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, methyltriisopropoxysilane Ethyltrimethoxysilane ethyltriethoxysilane ethyltri-n-propoxysilane ethyltriisopropoxysilane n-propyltrimethoxysilane n-propyltriethoxysilane n-propyltri-n-propoxysilane isopropyltriol Methoxysilane, isopropyltriethoxysilane, isopropyltri-n-propoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri-n-propoxysilane, phenylate Such as isopropoxycarbonyl silane. In addition, 3-aminopropyltrimethoxysilane, an alkyl group substituted on a silicon atom has a reactive functional group, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3 -Triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane , 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-carboxypropyltrimethoxysilane, 3-trihydroxysilyl -1- Propane - such as sulfonic acid can also be used.

(Dialkyldialkoxysilane)
There is no limitation on the type of dialkyldialkoxysilane. Examples of suitable ones are methyldimethoxysilane, methyldiethoxysilane, methyldi-n-propoxysilane, methyldiisopropoxysilane, ethyldimethoxysilane, ethyldiethoxysilane, ethyldi-n-propoxysilane, ethyldiisopropoxy Silane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-propoxysilane, dimethyldiisopropoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldi-n-propoxysilane, diethyldiisopropoxysilane, di-n- Propyldimethoxysilane, di-n-propylethoxysilane, di-n-propyldi-n-propoxysilane, di-n-propyldiisopropoxysilane, diisopropyldimethoxysilane, di- Propylethoxysilane, diisopropyl di-n-propoxysilane, diisopropyl diisopropoxysilane, di-n-butyldimethoxysilane, di-n-butylethoxysilane, di-n-butyldi-n-propoxysilane, di-n-butylsilane Diisopropoxysilane, di-sec-butyldimethoxysilane, di-sec-butylethoxysilane, di-sec-butyldi-sec-propoxysilane, di-sec-butyldiisopropoxysilane, di-tert-butyldimethoxysilane, Di-tert-butylethoxysilane, di-tert-butyldi-n-propoxysilane, di-tert-butyldiisopropoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldi-n-propoxysilane, diphe Such distearate isopropoxycarbonyl silane. In addition, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane or the like in which an alkyl group substituted on a silicon atom has a reactive functional group can also be used.

(Trialkylalkoxysilane)
There is no limitation on the type of trialkylalkoxysilane. Examples of suitable ones include trimethylmethoxysilane, trimethylethoxysilane, triethylethoxysilane, tri-n-propylmethoxysilane, tri-n-propylethoxysilane and the like.

(Other alkoxysilanes)
As the alkoxysilane, bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane, 1,2-bis (trimethoxysilyl) ethane, 1,2-bis (triethoxysilyl) ethane other than those described above Trialkoxy with two or more organic residues such as 1,4-bis (trimethoxysilyl) benzene, 1,4-bis (triethoxysilyl) benzene and 1,3,5-tris (trimethoxysilyl) benzene It is also possible to use one having a silyl group bonded thereto.

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

(Preferred combination of alkoxysilanes)
When two or more alkoxysilanes are used in combination, from the viewpoint of control of the sol-gel reaction, tetraalkoxysilane, monoalkyltrialkoxysilane, and monoalkyltrialkoxysilane are preferable as the combination, and among them, tetraalkoxysilane and More preferred is a combination of monoalkyltrialkoxysilanes. The tetraalkoxysilane can strengthen the silica skeleton and the monoalkyltrialkoxysilane can lower the refractive index. That is, control of the silica skeleton strength and the refractive index becomes possible by control of the blending ratio of the two. Further, from the viewpoint of wettability to a substrate, tetraalkoxysilane and dialkyldialkoxysilane, monoalkyltrialkoxysilane and dialkyldialkoxysilane are preferable.

(Proportion of alkoxysilane)
When two or more alkoxysilanes are used in combination, the compounding ratio is not particularly limited as long as the effects of the present invention are not significantly impaired. When using 2 types of alkoxysilanes together, 0.5: 9.5-5: 5 are preferable in silicon atom conversion of alkoxysilane from a viewpoint of the water resistance of the silica body formed, for example, 2: 8- 5: 5 is more preferable, and 2.5: 7.5-5: 5 is the most preferable.

  Furthermore, from the viewpoint of strengthening the skeleton of the porous structure, it is effective to include a tetraalkoxysilane, and the ratio of the silicon atom derived from tetraalkoxysilane to the silicon atom of all alkoxysilanes is usually 0.15 (mol / l). mol) or more, preferably 0.3 (mol / mol) or more, more preferably 0.35 (mol / mol) or more, and usually 0.95 (mol / mol) or less, preferably 0.90 (mol / mol) or less. or less, more preferably 0.8 (mol / mol) or less.

Here, the silicon atoms of all the alkoxysilanes refer to the sum of the number of silicon atoms that all the alkoxysilanes contained in the composition have. Therefore, even if the composition contains a compound having a silicon atom in addition to the alkoxysilane, the silicon atom of the compound does not contribute to the calculation of the ratio. In addition, the ratio of the silicon atom of the said alkoxysilane can be measured by < ²⁹ > Si-NMR.

  In the composition used for producing the porous layer suitable for the present invention, the content of the silicon-containing compound (silicon atom-containing compound) is usually 0.01% by weight or more, preferably 0, including the above-mentioned alkoxysilane. .1 wt% or more, more preferably 0.5 wt% or more, further preferably 1 wt% or more, and usually 50 wt% or less, preferably 30 wt% or less, more preferably 20 wt% % Or less, more preferably 15% by weight or less. If the content of the silicon atom-containing compound in the composition is less than 0.01% by weight, the surface properties of the porous film may be deteriorated in the heating step, and the appearance may be poor. On the other hand, if it exceeds 50% by weight, the base material tends to be influenced by the flatness of the substrate, and there is a possibility that the sol-gel reaction in the film forming process may become uneven in the surface direction.

  In addition, from the viewpoint of controlling the thickness of the obtained porous silica layer, the silicon atom-containing compound in the composition used for producing the porous silica layer of the present invention, an organic polymer as a template material described below, etc. The solid concentration is usually 0.02% by weight or more, preferably 0.5% by weight or more, and more preferably 1% by weight or more. Moreover, 50 weight% or less is preferable normally, 40 weight% or less is more preferable, and 35 weight% or less is more preferable.

<Water>
The composition used for producing the porous silica layer of the present invention contains water. Water is essential in the sol-gel reaction, but in the present production method, it plays an important role in controlling the surface tension of the composition and forming a high quality silica precursor film in the film forming process. Although there is no restriction | limiting in particular in the purity of the water to be used, Usually, you may use the water which processed any one or both in ion exchange and distillation. However, in the case of using the laminate of the present invention in a field of application particularly disfavoring minute impurities such as optical use laminates, it is desirable to use a porous silica layer having a higher purity. It is preferable to use pure water. Further, among impurities, contamination of 100 nm or more may affect the progress of the sol-gel reaction. Therefore, it is preferable to use water that has passed through a filter having a pore size of, for example, 0.01 μm to 2.5 μm.

  The amount of water used is such that the ratio of water to silicon atoms of all alkoxysilanes in the composition is usually 1 (mol / mol) or more, preferably 3 (mol / mol) or more, more preferably 5 (mol / mol) And above. Also, it is usually 300 (mol / mol) or less, preferably 200 (mol / mol) or less. When the ratio of water to silicon atoms of all the alkoxysilanes is in the above range, the control of the sol-gel reaction is easy, the pot life is long, and a homogeneous porous layer is formed, and the surface is smooth. And excellent in wear resistance. In addition, by setting the above-mentioned range, the sol-gel reaction easily progresses, the reaction progresses in a short time, and the water resistance is improved, when larger than this range. The amount of water can be calculated by the Karl Fischer method (coulometric titration method).

<Organic solvent>
The composition used to produce the porous silica membrane suitable for the present invention contains an organic solvent. Alcohols are most suitable as the organic solvent. Alcohols are preferred in order to allow the sol-gel reaction to proceed homogeneously during the formation of the porous silica film, since they have an affinity for the alkoxysilane, its hydrolyzate, and partial condensates. Further, by maintaining a stable state at the gas-liquid (composition) interface and the solid (base material) -liquid (composition) interface generated in the film forming step, it is effective to form a high quality silica precursor film. is there.

  There is no restriction on the type of alcohol. Examples of suitable ones are methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl -1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2, 2-dimethyl-1-propanol, 1-hexanol Monohydric alcohols such as 2-hexanol, 3-hexanol, ethylene glycol monomethyl ether, 2-ethoxyethanol, propylene glycol monomethyl ether, dihydric alcohols such as ethylene glycol and diethylene glycol, trihydric alcohols such as glycerin, cyclohexanol and the like Alicyclic Alcohol, and other aromatic alcohols such as benzyl alcohol. One of these may be used alone, or two or more of them may be used in any combination and ratio.

  Among these, monohydric alcohols and dihydric alcohols are preferable, and monohydric alcohols are more preferable, from the viewpoint of the progress of the hydrolysis reaction of the contained alkoxysilane. In addition, from the viewpoint of the surface properties of the obtained silica porous layer, 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. Therefore, it is preferable to use at least one selected from these.

  In addition, the boiling point of the organic solvent used is preferably 110 ° C. or less, more preferably 100 ° C. or less, in order to facilitate the formation of the structure of the silica-based precursor layer in the production process of the porous layer and to improve the wettability with the substrate. And 90 ° C. or less are more preferable. As such a thing, methanol, ethanol, 1-propanol, t-butanol, 2-propanol etc. are preferable, for example. On the other hand, from the viewpoint of suppressing deformation of the porous structure in the heating step, the boiling point of the organic solvent is preferably 100 ° C. or more, more preferably 110 ° C. or more, and more preferably 120 ° C. or more. As such a thing, 2-methyl- 1-propanol, 1-butanol, 1-pentanol is preferable, for example.

Furthermore, the above-mentioned alcohols having different boiling points may be mixed and used, and in that case, the difference in the boiling points of the alcohols to be combined is preferably 5 ° C. or more, 10 ° C. in order to suppress the azeotrope in each step. The above is more preferable, and 20 ° C. or more is more preferable. The ratio of the high boiling point alcohol to the total alcohol is usually 5% by weight or more, preferably 10% by weight or more, more preferably 40% by weight or more, still more preferably 60% by weight or more, particularly preferably 80% by weight or more. The upper limit of the ratio is usually 98% by weight. By setting this range, the smoothness of the surface of the obtained silica porous layer is improved.

The composition used for producing the porous silica layer of the present invention may contain an organic solvent other than the above-mentioned alcohols. For example, in order to improve the wettability with the below-mentioned base material and the film forming property in a film forming process, organic solvents other than alcohol can be used.
Examples of suitable organic solvents include ethers or esters such as methyl acetate, ethyl acetate, isobutyl acetate, ethylene glycol dimethyl ether and propylene glycol methyl ether acetate; ketones such as acetone and methyl ethyl ketone; formamide, N-methyl formamide N-ethylformamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylacetamide, N-ethylacetamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone, N -Formyl morpholine, N-acetyl morpholine, N-formyl piperidine, N-acetyl piperidine, N-formyl pyrrolidine, N-acetyl pyrrolidine, N, N'- diformyl piperazine, N, N Amides such as' -diformyl piperazine and N, N'-diacetyl piperazine; Lactones such as Y-butyrolactone; Ureas such as tetramethyl urea and N, N'-dimethyl imidazolidine; dimethyl sulfoxide and the like.

  The amount of the organic solvent used is optional as long as the effect of the present invention is not significantly impaired, but the content in the composition used for producing the porous silica layer of the present invention is usually 0.05% by weight or more. 1% by weight or more is preferable, 1% by weight or more is more preferable, and 10% by weight or more is more preferable. Also, the content is usually 50% by weight or less, preferably 40% by weight or less, and more preferably 30% by weight or less. By setting the amount of the organic solvent to be in this range, the porous layer can be stably produced.

<Catalyst>
The composition used for the production of the porous silica layer of the present invention may contain a catalyst. As the catalyst, for example, a substance that promotes the hydrolysis and dehydration condensation reaction of the alkoxysilane described above may optionally be used it can.
For example, hydrofluoric acid, phosphoric acid, boric acid, hydrochloric acid, nitric acid, sulfuric acid, formic acid, acetic acid, oxalic acid, maleic acid, methyl malonic acid, stearic acid, linolenic acid, benzoic acid, phthalic acid, citric acid, succinic acid Acids such as lactic acid, malic acid, mandelic acid, pyruvic acid, malonic acid, adipic acid, glutaric acid, glialic acid, salicylic acid, aconitic acid; amines such as ammonia, butylamine, dibutylamine and triethylamine; tetramethylammonium hydroxide, water Basic ammonium salts such as tetraethylammonium oxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide; bases such as pyridine; Lewis acids such as acetylacetone complex of aluminum; and other such as acidic and basic amino acids .

In addition, examples of the catalyst also include metal chelate compounds. Examples of the metal species of the metal chelate compound include titanium, aluminum, zirconium, tin, antimony and the like. As specific examples of the metal chelate compound, the following may be mentioned.
As an aluminum complex, for example, 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-buto Di-bis (acetylacetonato) aluminum, mono-tert-butoxy-bis (acetylacetonato) aluminum, tris (acetylacetonato) aluminum, diethoxy mono (ethylacetoacetate) aluminum, di-n-propoxy mono ( Ethylacetoacetate) Aluminum, diisopropoxy mono (ethylacetoacetate) aluminum, di-n-butoxy mono (ethylacetoacetate) aluminum, di-sec-butoxy mono (ethylacetoacetate) aluminum, di-tert- Butoxy mono (ethylacetoacetate) aluminum, monoethoxy bis (ethylacetoacetate) aluminum, mono-n-propoxy bis (ethylacetoacetate) aluminum, mono Sopropoxy.bis (ethylacetoacetate) aluminum, mono-n-butoxy.bis (ethylacetoacetate) aluminum, mono-sec-butoxy.bis (ethylacetoacetate) aluminum, mono-tert-butoxy.bis (ethylacetoacetate) Aluminum chelate compounds such as aluminum and tris (ethylacetoacetate) aluminum can be mentioned.

  Examples of 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 Ruacetonato) 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 (acetylacetonate) titanium, mono-tert-butoxy tris (acetylacetonato) titanium, tetrakis (acetylacetonato) titanium, triethoxy mono (ethylacetoacetate) titanium Tri-n-propoxy mono (ethylacetoacetate) titanium, triisopropoxy mono (ethylacetoacetate) titanium, tri-n-butoxy mono (ethylacetoacetate) titanium, tri-sec-b X-mono (ethylacetoacetate) titanium, tri-tert-butoxy mono (ethylacetoacetate) titanium, diethoxy bis (ethylacetoacetate) titanium, di-n-propoxy bis (ethylacetoacetate) titanium, diiso Propoxy-bis (ethylacetoacetate) titanium, di-n-butoxy-bis (ethylacetoacetate) titanium, di-sec-butoxy-bis (ethylacetoacetate) titanium, di-tert-butoxy-bis (ethylacetoacetate) Titanium, monoethoxy tris (ethylacetoacetate) titanium, mono-n-propoxy tris (ethylacetoacetate) titanium, monoisopropoxy tris (ethylacetoacetate) titanium, mono-n-butoxy tris (ethylaceto) Acetate) Titanium, mono-sec-butoxy tris (ethylacetoacetate) titanium, mono-tert-butoxy tris (ethylacetoacetate) titanium, tetrakis (ethylacetoacetate) titanium, mono (acetylacetonato) tris (ethylacetoate) Acetate) titanium, bis (acetylacetonato) bis (ethylacetoacetate) titanium, tris (acetylacetonato) mono (ethylacetoacetate) titanium and the like can be mentioned.

Among the above-mentioned ones, in order to control the hydrolysis and dehydration condensation reaction of the alkoxysilane compound more easily, acids or metal chelate compounds are preferable, and acids are more preferable. In addition, only 1 type may be used for a catalyst and 2 or more types may be used together by arbitrary combinations and ratios.
The amount of the catalyst used is optional, as long as the effect of the present invention is not significantly impaired, but the amount is usually 0.001 mol or more, preferably 0. 1 to 10 mol per alkoxysilane in the composition used for producing the porous silica membrane of the present invention. The amount is preferably 003 mol or more, particularly preferably 0.005 mol or more, and usually 0.8 mol or less, preferably 0.5 mol or less, particularly preferably 0.1 mol or less. By setting the amount of the catalyst used in this range, the hydrolysis reaction proceeds appropriately, and after the preparation, active groups such as silanol groups decrease in the porous silica layer, the water resistance of the porous silica layer is improved, and the reaction Control is facilitated, and the surface concentration of the porous silica layer is improved by further increasing the catalyst concentration during production.

<PH>
The composition used for producing the porous silica layer of the present invention preferably has a pH of 6 or less from the viewpoint of film formation. The pH of the composition is more preferably 5.5 or less, still more preferably 5.0 or less, and particularly preferably 4.5 or less. By setting it in this range, the surface modification of the below-mentioned base material can be performed simultaneously at the time of manufacture of the silica porous membrane of the present invention, and the film forming property tends to be further improved.

<Others>
The composition used for producing the porous silica membrane of the present invention may contain components other than the above-mentioned alkoxysilane, water, organic solvent and catalyst. Moreover, the said component may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
(Organic polymer)
The composition used for producing the porous silica membrane of the present invention may contain an organic polymer as a template material, and the composition containing the organic polymer was applied to a substrate to form a silica-based precursor film Thereafter, by removing all or part of the organic polymer in the extraction step, a porous silica membrane having higher porosity can be obtained.

  From the viewpoint of forming a porous structure, the number average molecular weight of the organic polymer used is usually 500 or more, preferably 1,000 or more, more preferably 2,000 or more, and particularly preferably 5,000 or more. By making the number average molecular weight in this range, it becomes easy to maintain high porosity of the obtained silica porous layer, and it is possible to stably produce a low refractive index silica porous layer. While the upper limit of the number average molecular weight of the organic polymer is not limited, it is usually 100,000 or less, preferably 70,000 or less, and more preferably 40,000 or less. By making the number average molecular weight in this range, thickening of the composition is prevented, and the film forming property is improved.

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

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

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

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

  From the viewpoint of the pot life of the composition used for producing the porous silica membrane of the present invention and the stability of the silica precursor film in the film forming process, as the organic polymer, (meth) acrylic polymers, polyether polymers Molecules are preferred, and polyether polymers are more preferred. Among them, from the viewpoint of the affinity with the hydrolyzable group-containing silane, the alkylene glycol compound of the repeating unit constituting the polyether polymer preferably has 2 to 4 carbon atoms, and more preferably 2 or 3 carbon atoms.

Furthermore, in order to stably maintain the structure of the silica-based precursor film from the film forming step to the heating step, as the organic polymer, a copolymer obtained by combining alkylene glycol compounds having different carbon numbers is preferable. At this time, the content of the alkylene glycol compound having a small number of carbon atoms in the total of the alkylene glycol compound, that is, the content of the alkylene glycol compound having high affinity with the silanol group of the hydrolyzable group-containing silane is optional as long as the effects of the present invention are not significantly impaired. However, it is usually 20 wt% or more, preferably 23 wt% or more, more preferably 25 wt% or more, and is usually 100 wt% or less, preferably 90 wt% or less, more preferably 85 wt% or less. Within the above range, the organic polymer as a template material is more stably present against the hydrolyzate or condensate of the hydrolyzable group-containing silane formed in the sol-gel reaction of the hydrolyzable group-containing silane. can do.

  When an organic polymer is used, the content of the organic polymer in the composition used for producing the porous silica membrane of the present invention is preferably 0.1% by weight or more, and more preferably 0.5% by weight or more. Preferably, 1.2% by weight or more is more preferable, and 1.4% by weight or more is particularly preferable. When the content of the organic polymer in the composition is at least the lower limit, the sol-gel reaction of the hydrolyzable group-containing silane in the film forming step can be stabilized. Although the upper limit of the content of the organic polymer in the composition is not limited, 50% by weight or less is preferable, 40% by weight or less is more preferable, and 30% by weight or less is particularly preferable. By not exceeding this upper limit, thickening of the composition is prevented, and the film forming property is improved.

(Surfactant)
The composition used for the production of the porous silica layer of the present invention may contain a surfactant as long as the effects of the present invention are not significantly impaired. Film formation may be significantly improved by the addition. As the surfactant, any of known ones may be used, and the kind, combination, and ratio thereof are not particularly limited, and the following two or more surfactants may be used.

  Specific examples of the surfactant include nonionic surfactants such as polyethylene glycol, polypropylene glycol and polyisobutylene glycol, anionic surfactants, cationic surfactants, amphoteric surfactants and lipophilic groups Examples thereof include fluorocarbon surfactants having a carbon group, silicone surfactants having an oleophilic group of a siloxane chain, and surfactants having an oleophilic group of an alkyl group. The surfactant is preferably selected from two or more of them from the viewpoint of the film forming property of the composition, and among them, a nonionic surfactant and a fluorosurfactant (especially containing a perfluoroalkyl group) And the combination of the nonionic surfactant and the silicone surfactant (in particular, those containing a siloxane bond). The hydrophilic group of these surfactants is preferably, for example, a hydroxyl group, a carbonyl group or a carboxyl group. Also, polyether, polyglycerin and the like are preferable.

As a fluorochemical surfactant, for example, hexaethylene glycol (1,1,2,2,3,3-hexafluoropentyl) ether, 1,1,2,2-tetrafluorooctyl (1,1,2,2 And-tetrafluoropropyl) ether, sodium perfluorododecyl sulfonate and the like.
Moreover, as silicone type surfactant, SH21 series, SH28 series (Toray Dow Corning Co., Ltd.) etc. are mentioned, for example.

  The content of the surfactant in the composition used for producing the porous silica membrane of the present invention is the obtained porous silica membrane as the ratio of the surfactant to the silicon atoms of the total hydrolyzable group-containing silane in the composition. From the viewpoint of the surface properties of the above, 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. It is at most 05 (mol / mol), preferably at most 0.04 (mol / mol), more preferably at most 0.03 (mol / mol).

<Composition of composition>
Each component which comprises the composition mentioned above is mixed, and the composition used for manufacture of the silica porous layer of this invention is prepared. At this time, the order of mixing the respective components is not limited. Moreover, each component may mix the whole amount at once, may divide it into 2 or more times, and may mix it continuously or intermittently.
However, in order to control the sol-gel reaction, which is conventionally considered to be difficult to control, to prepare the composition more industrially and advantageously, it is preferable to mix in the following manner. That is, the alkoxysilane is mixed with water, a solvent, and a catalyst, and the mixture (hereinafter sometimes referred to as "alkoxysilane mixture") is subjected to a certain sol-gel reaction (aging) to hydrolyze the alkoxysilane to some extent. And dehydration polycondensation. And when using an organic polymer as a template material, an organic polymer is mixed with an alkoxysilane mixture, and a composition is prepared. Thereby, the affinity between the silane and the organic polymer as a template material can be maintained under sol-gel reaction conditions. Aging may be carried out after mixing the mixture and the organic polymer.

<Aging>
(Aging of alkoxysilane mixture)
In the case of the said ripening, in order to advance the hydrolysis * dehydration-polycondensation reaction of an alkoxysilane, it is preferable to heat. The heating conditions are not particularly limited as long as they do not exceed the boiling point of the solvent used, but usually 5 ° C. or higher, preferably 10 ° C. or higher, more preferably 20 ° C. or higher, and most preferably 30 ° C. or higher . By making the heating temperature appropriate, a sufficient sol-gel reaction proceeds, the condensation product of the alkoxysilane is sufficiently grown, and the strength of the formed film becomes high. In addition, when a sufficient sol-gel reaction proceeds, when using an organic polymer as a template material for forming porous pores, affinity with the organic polymer is easily obtained. On the other hand, 90 degrees C or less is preferable and, as for the upper limit of heating temperature, 80 degrees C or less is more preferable. By making heating temperature below this upper limit, the condensation reaction of an alkoxysilane advances too much, a condensate can form a precipitate and it can prevent that an alkoxysilane mixture becomes non-uniform | heterogenous. In addition, the molecular motion of the organic polymer as the template material in the silane mixture becomes intense, and the possibility that the affinity between the silane and the organic polymer can not be controlled is also suppressed.

  Also, there is no limitation on the aging time accompanied by heating, but it is usually 0 minutes or more, preferably 10 minutes or more, more preferably 20 minutes or more, more preferably 30 minutes or more, and usually 20 hours or less, preferably 15 hours or less More preferably, it is 8 hours or less, More preferably, it is 4 hours or less. By setting the aging time in this range, the reaction can be easily proceeded uniformly, a sufficient sol-gel reaction proceeds, and the affinity between the alkoxysilane and the organic polymer (template material) can be easily obtained.

Furthermore, there is no limitation on the pressure condition at the time of aging of the alkoxysilane mixture, but in general, it is preferable to carry out the aging under normal pressure. At normal pressure, there is little change in pressure, so changes in the boiling point of the solvent due to changes in pressure and evaporation of the solvent during ripening prevent changes in the composition ratio and stabilize the mixture. Sex is high.
Moreover, after the said ripening, it is preferable to further mix and dilute the organic solvent for the composition used before a film forming process. This makes it possible to reduce the sol-gel reaction rate in the composition and to maintain the pot life of the composition for a long time. Further, from the viewpoint of yield in the production of the porous silica membrane, it is preferable to carry out aging without heating. Aging without heating may be performed after preparation of the composition. From the viewpoint of the pot life of the composition, a neutralization step or a catalyst removal step may be performed.

{Film forming process}
In the film forming step, the composition used for producing the above-mentioned porous silica layer of the present invention is applied onto a substrate and developed to produce a silica-based precursor film.
In addition, although the film forming process may be performed once, it may be divided into two or more times and may be performed. For example, if the film forming step is performed twice or more through a rough drying step described later, it is possible to form a porous silica membrane having a laminated structure. This is useful, for example, when it is desired to form a porous silica film having different refractive indices by laminating.

The base material to be used is not particularly limited, and it may be any of an adhesive layer, a sheet which can be removed later, or a substance having a refractive index of 1.40 or more provided on the opposite side of the adhesive layer. Is a material that transmits visible light that can be used for optical applications, and may be resin or glass, preferably glass, and particularly preferably optical glass. This substrate will be adjacent to the porous layer. The refractive index of the base material at this time is preferably 1.40 or more because an optical effect due to the difference in refractive index with the porous layer can be easily obtained.

Moreover, the center line average roughness of the silica porous membrane formation surface of a base material is also arbitrary. However, from the viewpoint of film formability of the porous silica film to be formed, the center line average roughness is preferably 10 nm or less, more preferably 8 nm or less, still more preferably 5 nm or less, and particularly preferably 3 nm or less. The maximum height R _max of the surface roughness of the substrate is preferably 100 μm or less, particularly 10 μm or less, from the viewpoint of the film formability of the porous silica membrane to be formed.

The center line average roughness and the maximum height R _max of the surface roughness are measured by a general-purpose surface roughness meter (for example, Surfcom 570A manufactured by Tokyo Seimitsu Co., Ltd.) according to JIS-B 0601: 1994.
<Film forming method>
In the present invention, the film forming method of the composition used for producing the porous silica layer of the present invention on a substrate is not particularly limited. For example, a spin coater, a spray coater, a die coater, a bar coater, a table coater, an applicator, The method of apply | coating using a doctor blade coater etc., the dip coating method, the inkjet method, the screen printing method, the gravure printing method, the flexographic printing method etc. are mentioned.

  In the dip coating method, the substrate may be dipped in the composition used for producing the porous silica membrane of the present invention and pulled up at an arbitrary speed. There is no limitation on the pulling speed at this time, but usually 0.01 mm / sec or more, preferably 0.05 mm / sec or more, more preferably 0.1 mm / sec or more, and usually 50 mm / sec or less, preferably 30 mm / sec. Or less, more preferably 20 mm / second or less. By keeping the pulling speed in this range, it is possible to prevent the film thickness from becoming uneven. On the other hand, the speed at which the substrate is immersed in the composition is not limited, but in general, it is preferable to immerse the substrate in the composition at a rate similar to the pulling speed. In addition, immersion may be continued for an appropriate time between immersion of the substrate in the composition and pulling up. There is no limitation on the time for which this immersion is continued, 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. By immersing for a time in this range, adhesion to the substrate and smoothness can be enhanced.

  Furthermore, when the composition used for producing the porous silica layer of the present invention is applied by spin coating, the rotation speed is usually 10 rotations / minute or more, preferably 50 rotations / minute or more, more preferably 100 rotations / minute. It is more than a minute, and usually 100,000 rotations / minute or less, preferably 50,000 rotations / minute or less, more preferably 10,000 rotations / minute or less. By setting the rotation speed within this range, it is possible to prevent the occurrence of unevenness and to prevent the excessive vaporization of the solvent, the reaction such as hydrolysis of alkoxysilanes sufficiently proceeds, and the water resistance is also improved.

In particular, in order to form a sol precursor based on a sol-gel during film formation in a stable state regardless of the composition of the composition, the distance between the discharge portion of the composition and the substrate is controlled, and It is preferred to cast the composition. By forming a film in a limited space formed from the discharge part and the base material, the sol-gel reaction can be advanced under a certain environment, and a homogeneous silica-based precursor film can be formed. Specifically, the distance between the discharge portion of the composition and the substrate is preferably 100 μm or less, more preferably 80 μm or less, still more preferably 70 μm or less, and most preferably 50 μm or less. When this distance does not exceed 100 μm, the progress of the sol-gel reaction becomes even around the discharge part and around the base material, preventing the occurrence of convection in the film in the wet state, and the silica porous film is stably obtained. be able to. On the other hand, the lower limit of this distance is preferably 0.1 μm or more, more preferably 0.3 μm or more, still more preferably 0.5 μm or more, and most preferably 0.8 μm or more. When the thickness is 0.1 μm or more, the sol-gel reaction proceeds stably without an increase in shear during casting to a composition.

Furthermore, in order to realize highly reliable film thickness control over a wide range (large area) as an optical functional layer, a method using a die coater, a bar coater, a table coater, an applicator, a doctor blade coater or the like is preferable. The method used is more preferred.
In the die coating method, the composition used for producing the porous silica film of the present invention is supplied at a constant flow rate from a solution supply point, and the composition is discharged from a die lip through a slit to discharge the silica precursor film on the substrate surface. At this time, the target porous silica layer can be formed by transporting the substrate at a constant speed.

The width of the slit is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, and usually 100 μm or less, preferably 80 μm or less, more preferably 50 μm or less. When the width of the slit is equal to or more than the above lower limit value, clogging due to contamination is prevented, and when it is equal to or less than the above upper limit value, the film can be formed uniformly.
The gap (distance) between the die lip (slit) and the substrate is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, further preferably 30 μm or more, and usually By setting the thickness to 100 μm or less, preferably 80 μm or less, more preferably 50 μm or less, a good quality silica-based precursor film can be obtained.

  The discharge flow rate from the die lip is not particularly limited, but is usually 1 to 100 cc / min, preferably 1 to 50 cc / min, more preferably 1 to 20 cc / min, still more preferably 2 to 10 cc / min, and most preferably 3 ~ 6 cc / min. By setting the discharge flow rate to the above lower limit or more, the allowable range of the slit speed accuracy at the time of casting is expanded, and there is a tendency that the substrate can be easily enlarged. On the other hand, by setting the upper limit value or less, convection can be prevented from occurring in the discharged composition, and a stable wet film can be easily formed.

  The coating speed is not particularly limited, but is usually 5 to 300 mm / sec, preferably 10 to 200 mm / sec, more preferably 20 to 100 mm / sec, still more preferably 30 to 80 mm / sec, and most preferably 40 to 60 mm / Second. By setting the coating speed to the above lower limit or more, the tolerance of the casting conditions of the silica-based precursor film in the film forming step is broadened, the productivity is improved, and the film forming step is achieved by setting the above upper limit or less. In the above, the shear stress applied to the silica-based precursor film is reduced, and the structure composed of the organic polymer as the template material and the silica component can be stably maintained.

  Although there is no restriction | limiting in particular in coating stop time, Usually 0.1 to 3 second, Preferably 0.1 to 2 second, More preferably 0.2 to 1 second, Still more preferably 0.2 to 0.8 second , Most preferably 0.3 to 0.6 seconds. By setting the application stop time to the above lower limit value or more, the interface state between the substrate and the silica-based precursor film is stabilized, adhesion with the substrate is improved, leveling of the film surface progresses, and the appearance of the film is beautiful Will be kept. By setting the content to the above upper limit or less, the sol-gel reaction at the interface between the base material and the silica-based precursor film does not proceed excessively, and local defects do not occur during casting.

  The coating distance is not particularly limited, but is usually 0.05 to 500 m, preferably 0.1 to 300 m, more preferably 0.5 to 100 m, still more preferably 0.8 to 50 m, and most preferably 1 to 5 m It is. When the coating distance is at least the above lower limit value, there is no fear that the unstable state at the initial stage of casting in the film forming process is exerted on the entire silica precursor film, and if it is at most the above upper limit value And the possibility of affecting the surface properties of the porous silica membrane is eliminated.

The leveling accuracy of the die lip and the substrate support is normally ± 5 μm or less, preferably ± 2 μm or less, more preferably ± 1 μm or less.
The shape of the die that can be used is not particularly limited as long as it can uniformly distribute the solution etc. in the lateral direction. Examples include those having a T-die shape used in general film casting, or those having a fishtail die shape, or those having a coat hanger die shape. Furthermore, in order to make the distribution in the die lateral direction more uniform, it is desirable to have a die lip spacing adjustment mechanism.

  The wet film thickness at the time of film formation is not particularly limited, but usually 0.1 to 100 μm, preferably 0.5 to 80 μm, more preferably 1 to 55 μm, still more preferably 5 to 40 μm, and 10 to 25 μm. Is most preferred. Within this range, it becomes easy to control the progress of the sol-gel reaction of the composition in the film forming process, and is less susceptible to the wettability with the substrate, thereby improving the leveling effect of the film, The appearance is improved.

  For example, in the case of die coating, the wet film thickness is preferably controlled by the discharge liquid amount and the moving speed of the substrate, usually 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, and usually 60 μm or less, preferably 50 μm By setting the thickness to 40 μm or less, it is possible to obtain a uniform porous silica film with less uneven coating.

<Film deposition environment>
There is no particular limitation on the relative humidity at the time of the film forming step, but by controlling the relative humidity, a more stable continuous coating becomes possible.

For example, the relative humidity is usually 5% RH or more, preferably 10% RH or more, more preferably 15% RH or more, more preferably 20% RH or more, and usually 85% RH or less, preferably 80% RH or less, It is preferable to form the silica-based precursor film under an environment of preferably 75% or less RH.
The temperature at which the film forming step is carried out is not particularly limited, but is usually 0 ° C. or more, preferably 10 ° C. or more, more preferably 15 ° C. or more, still more preferably 20 ° C. or more, most preferably 25 ° C. or more, usually 100 ° C or less, preferably 80 ° C. or less, more preferably 70 ° C. or less, more preferably 60 ° C. or less, most preferably 50 ° C. or less. By setting the temperature at the time of producing the silica-based precursor film in this range, the sol-gel reaction proceeds at an appropriate rate, it is easy to obtain a homogeneous silica-based precursor film, and the amount of unhydrolyzed alkoxysilane decreases. The durability of the resulting porous silica membrane is improved.

Furthermore, there is no particular limitation on the degree of cleanness when the film forming step is carried out, but from the viewpoint of suppressing the progress of the sol-gel reaction around the core defect and the core defect with the contamination existing on the base The number of dust particles having a dust diameter of 0.5 μm or more is preferably 3,000,000 or less, more preferably 50,000 or less, and still more preferably 5,000 or less.
Further, the atmosphere in the film forming process is not limited. For example, the film formation of the silica-based precursor film may be performed in an air atmosphere, or the film formation of the silica-based precursor film may be performed in an inert atmosphere such as argon.

<Pre-processing>
In the method for producing a silica porous layer used in the present invention, the wettability of the composition, the silica to be produced prior to film formation on a substrate of the composition used for producing the silica porous layer of the present invention From the viewpoint of adhesion of the precursor film, the substrate may be subjected to surface treatment. Examples of such surface treatment of the substrate include silane coupling treatment, corona treatment, UV ozone treatment, plasma treatment and the like. Such surface treatment may be performed alone or in combination of two or more.

<Post-processing>
(Coarse drying)
In the method for producing a porous silica membrane of the present invention, rough drying is carried out to roughly dry the silica-based precursor membrane for the purpose of removing the alcohol or catalyst in the silica-based precursor membrane after the above-mentioned film forming step. A process may be performed. By performing the rough drying step, the alcohol, water, and catalyst in the silica-based precursor film are removed, whereby the structure is obtained in a state where the organic polymer (template material) and the silica component present in the precursor film are stable. To stabilize the structure of the silica-based precursor film.

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

  Although the temperature at the time of rough drying is not limited, it is usually preferable to be room temperature or higher. In particular, when heat drying is performed, the temperature is usually 20 ° C. or more, preferably 30 ° C. or more, more preferably 40 ° C. or more, most preferably 60 ° C. or more, and usually 200 ° C. or less, preferably 180 ° C. or less, more preferably Is preferably in the range of 150.degree. C. or less, most preferably 100.degree. C. or less. In addition, although the temperature at the time of heat drying may be constant, you may fluctuate.

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

The atmosphere at the time of rough drying is also not limited, and may be air atmosphere, inert gas atmosphere such as nitrogen atmosphere, or vacuum atmosphere. These may be selected in consideration of the characteristics of the silica precursor film and the like. However, it is usually preferable to have a clean atmosphere.
The rough drying time is also not limited, and it is optional as long as alcohol, water and catalyst in the silica precursor film can be removed, but conditions such as temperature, pressure and humidity at the time of rough drying, and the porous silica membrane of the present invention It is preferable to determine in consideration of the boiling point of the alcohol and the solvent contained in the composition used for the production of, the process speed, the characteristics of the silica precursor film, and the like. The rough drying time is preferably in the range of usually 1 second or more, preferably 1 minute or more, more preferably 1 hour or more, and usually 100 hours or less, preferably 24 hours or less, more preferably 3 hours or less.

(Acid and base treatment)
The silica-based precursor film can also be contacted with an acid or a base after the above-described film forming step. By this step, the hydrolysis condensation reaction of the alkoxysilanes of the silica-based precursor film can be promoted, and the structure of the silica-based precursor film can be maintained to form a stable porous silica film, which is preferable.

Preferred acids to be contacted include readily volatile acids such as hydrogen chloride, formic acid, acetic acid, trifluoroacetic acid and the like. One of these acids may be used alone, or two or more of these acids may be used in combination. Moreover, as a preferable base, ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine, isopropylamine, n-butylamine, cyclopentylamine, cyclohexylamine and the like can be mentioned. One of these bases may be used alone, or two or more may be used in combination.

As a method of contacting the silica-based precursor film with an acid or a base, a method using a liquid or solution or a vapor of an acid or a base can be mentioned. Moreover, an acid or a base can be melt | dissolved in the organic solvent used at the extraction process mentioned later, and it can also be made to contact simultaneously with an extraction process.
Moreover, you may heat at the time of an acid * base process. The heating temperature is usually room temperature or more, preferably 40 ° C. or more, more preferably 100 ° C. or more, preferably 200 ° C. or less, more preferably 180 ° C. or less, particularly preferably 120 ° C. or less.

The time for acid / base treatment is optional as long as the effects of the present invention are not significantly impaired, but it is usually 30 seconds or more, preferably 10 minutes or more, more preferably 30 minutes or more, and usually 5 hours or less, preferably It is 2 hours or less, more preferably 1 hour or less.
The pressure at the time of the acid / base treatment is optional as long as the effects of the present invention are not significantly impaired, but may be a reduced pressure environment, and when heating, the pressure is usually 0.2 MPa or less, preferably 0.15 MPa Hereinafter, more preferably, it is 0.1 MPa or less. On the other hand, the lower limit of the pressure is not limited, but is usually 10 ⁻⁴ MPa or more, preferably 10 ⁻³ MPa or more, more preferably 10 ⁻² MPa or more. By setting it in this range, the volatilization of alcohols proceeds more than the sol-gel reaction of alkoxysilane, and it can be easily prevented from becoming a highly hygroscopic silica porous film, thereby reducing the environmental dependence of optical properties. be able to.

<Extraction process>
After the above-mentioned film forming step, if necessary, the silica-based precursor film is brought into contact with a solvent to carry out an extraction step of the organic polymer which is a template material. A porous structure having a higher porosity can be obtained by removing the organic polymer of the template material from the structure formed by the silica component comprising alkoxysilane by contact with a solvent. Furthermore, since the obtained porous silica film has a low refractive index, high optical properties are realized.

  The solvent used for extraction is not particularly limited, but a substance having high affinity to the organic polymer which is a template material is preferable. If the solvent has high affinity, the organic polymer is easily dissolved, and the organic polymer can be easily removed from the structure formed by the silica component. The solvent is preferably a polar solvent, and among them, monohydric alcohols, polyhydric alcohols, ketones, ethers, esters, and amides, or one or more hydrophilic solvents are preferable. When combining two or more types of hydrophilic solvents, they can be mixed and used, or they can be treated alone with each solvent and combined. Furthermore, the same kind of treatment solution can be repeatedly applied.

  The extraction method is not particularly limited. For example, immersing the silica-based precursor film in a solvent, washing the surface of the silica-based precursor film with the solvent, spraying the solvent onto the silica-based precursor film, spraying the solvent vapor onto the silica-based precursor film, etc. Method is mentioned. Alternatively, the organic polymer can be positively extracted by immersing the silica-based precursor film in a solvent and using ultrasonic waves or stirring the solvent.

Moreover, you may heat at the time of extraction. The heating temperature in this case may usually be 200 ° C. or less. Preferably it is 180 degrees C or less, More preferably, it is 120 degrees C or less. Also, the temperature is usually room temperature or more, preferably 40 ° C. or more, more preferably 60 ° C. or more.
As described above, by performing the extraction process, it is possible to obtain a laminate in which the porous silica film having a high porosity is formed on the base material.

<Drying process>
The drying step is a step of removing the solvent used for extraction in the extraction step from the silica-based precursor film.
At this time, the drying temperature is optional as long as the effects of the present invention are not significantly impaired, but it is usually 200 ° C. or less, preferably 180 ° C. or less, more preferably 120 ° C. or less, still more preferably 100 ° C. or less, and usually room temperature or more. Preferably it is 40 degreeC or more, More preferably, it is 60 degreeC or more. Further, the atmosphere in the drying step is optional 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.

<Heating process>
After the aforementioned film forming step, a heating step of heating the silica-based precursor film formed of the composition used for producing the laminate of the present invention is performed. The organic solvent and water in the composition used for producing the laminate of the present invention in the silica-based precursor film are dried and removed by the heating step, and the film is cured to be used in the laminate of the present invention The silica porous membrane which is an example of a porous layer is formed.

  Although the method of heat treatment is not particularly limited, as an example, a furnace for arranging a base material in a heating furnace (bake furnace) and heating a silica-based precursor film comprising a composition used for producing a laminate of the present invention In-baking method, hot plate method of mounting a substrate on a plate (hot plate) and heating a silica-based precursor film comprising the composition of the present invention through the plate, upper surface side and / or lower surface of the substrate There is a method of disposing a heater on the side and irradiating an electromagnetic wave (for example, infrared rays) from the heater to heat the silica-based precursor film made of the composition used for producing the laminate of the present invention.

  The heating temperature is not limited, and it is optional as long as it can cure the silica-based precursor film made of the composition used for producing the laminate of the present invention, but generally 80 ° C. or more, preferably 100 ° C. or more, more preferably 120 ° C. or more The temperature is more preferably 150 ° C. or more, most preferably 180 ° C. or more, and usually 600 ° C. or less, preferably 550 ° C. or less, more preferably 500 ° C. or less, most preferably 450 ° C. or less. By making heating temperature more than a lower limit, the refractive index of the film obtained becomes stably low, and it can prevent coloring. On the other hand, by making heating temperature below an upper limit, the adhesiveness of a base material and the silica porous membrane of this invention can be improved.

Moreover, an organic polymer can be removed without performing the above-mentioned extraction process by performing a heating process in air 180 degreeC or more.
Furthermore, from the viewpoint of the optical performance and peel strength of the laminate after providing the adhesive layer, the heating temperature is preferably 70C to 570C, more preferably 150C to 480C, and most preferably 180C to 300C. . Silica generally has silanol groups on its surface, and the amount of silanol groups decreases as the heating temperature increases, as condensation reaction between silanol groups proceeds. Therefore, by setting the heating temperature to the lower limit value or more, the amount of silanol groups becomes appropriate, and the surface is prevented from becoming excessively hydrophilic, and as a result, the moisture absorption of the porous film is suppressed, and the porous film The refractive index is kept low and the optical performance of the laminate of the invention is kept high. On the other hand, by setting the heating temperature to the upper limit value or less, the condensation reaction of silanol proceeds appropriately, so distortion is less likely to occur in the silica skeleton, defects such as micro cracks are less likely to occur, and an adhesion layer is provided. The adhesive can be prevented from infiltrating into the cracks to increase the refractive index of the porous film, and as a result, the optical performance of the laminate can be kept high.

In the heating step, heating may be performed continuously at the above-described heating temperature, but heating may be performed intermittently.
When heating, the temperature rising rate is optional as long as the effects of the present invention are not significantly impaired, but it 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 increased at a temperature of at most ° C / min. By setting the heating rate to the lower limit value or more, the film becomes too dense, and the possibility of the film distortion becoming large and the water resistance becoming low can be prevented. Further, by setting the heating rate to the upper limit value or less, the possibility of causing membrane distortion to be increased and water resistance to be lowered, and cracking, breakage and the like of the porous silica layer and the base material can be reduced.

  The heating time is optional 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. By setting the heating time to the lower limit value or more, curing of the porous silica membrane proceeds sufficiently, and by setting the heating time to the upper limit value or less, cracking, breakage or the like of the porous silica membrane and the base material can be prevented.

Although the atmosphere at the time of heating is optional as long as the effects of the present invention are not significantly impaired, an environment in which drying unevenness hardly occurs is preferable. Among them, it is preferable to carry out heating in the atmosphere. It is also possible to carry out an inert gas treatment and carry out heating in an inert atmosphere.
As described above, the mesoporous layer which can be used in the present invention by curing the silica precursor film comprising the composition used for producing the porous silica layer used in the laminate of the present invention by performing the heat treatment A porous silica layer can be obtained, which is an example of

[Method of manufacturing laminate]
In the present invention, an adhesive layer is provided on the whole or a specific area on the porous layer. As this adhesive layer, the component of the adhesive layer containing the polymer compound of the present invention is placed on release paper and the like, this is pasted on the porous layer which has already been formed, and By peeling off, the laminate of the present invention can be obtained. At this time, the adhesive layer is adhered to the porous layer with its own adhesive property to obtain the laminate of the present invention. In this laminate, when the polymer of the adhesive layer falls within the range specified in the present invention, even if the temperature is increased and accelerated test is conducted, it is distributed only on the very surface of the porous layer and the penetration into the inside is minimal. Stay in Therefore, the porous layer can fully exhibit the characteristics as a low refractive film.

[Example]
EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples. However, the present invention is not limited to the following examples, and can be arbitrarily changed and implemented without departing from the scope of the present invention.
Example 1
[Preparation of composition for forming porous film]
6.8 g of tetraethoxysilane, 6.9 g of methyltriethoxysilane, 2.3 g of ethanol, 5.6 g of H ₂ O, and 13 g of 0.3% by weight aqueous solution of hydrochloric acid are mixed and further stirred at 60 ° C. for 30 minutes at room temperature The mixture (A) was adjusted by carrying out.

Next, the above mixture is added to a mixture (B) obtained by mixing 6.2 g of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (PLURONIC P123 (number average molecular weight: Mn to 5800) manufactured by BASF) and 3.1 g of ethanol. (A) was added, and the mixture (C) was adjusted by stirring for 30 minutes at room temperature.
A composition for forming a porous film was obtained by mixing 50 ml of this mixture (C) with 50 ml of 1-butanol as a dilution solvent and stirring for 30 minutes at room temperature.

[Production of porous coated substrate]
The obtained composition was filtered with a PTFE membrane filter with a pore diameter of 0.45 μm, and 1.5 ml was dropped to a 760 × 520 mm glass substrate (MICRO SLIDE GLASS: S9112 manufactured by Matsunami Glass Industry Co., Ltd.). Then, a thin film was formed by rotating at 1200 rpm for 60 seconds with a spin coater manufactured by Mikasa.

Next, the thin film-coated glass substrate obtained was heated at 240 ° C. for 20 minutes using an oven (manufactured by ESPEC: Perfect Oven STPH-201) to obtain a porous silica coated substrate.
[Calculation of refractive index and thickness of porous layer]
By measuring the reflection spectrum of the porous silica coated surface formed on the glass substrate (refractive index 1.52) with a spectral film thickness meter (FE-3000 manufactured by Otsuka Electronics Co., Ltd.) and fitting with the Cauthy model, The refractive index and the film thickness were calculated to be 1.19 and 530 nm.

[Calculation of porosity of porous layer]
The porosity of the porous layer was calculated using the refractive index obtained above and the refractive index of the non-porous material (silica): 1.46 to be 63%.
[Reflectance difference of porous coated substrate]
The average is calculated for the maximum value and the minimum value of the maximum and minimum values of the maximum and minimum peak reflectances within the range of 400 nm to 1000 nm of the reflection spectrum obtained above and the half value width is 10 nm or more. The value obtained by taking the difference of the average of was taken as the reflectance difference: ΔR. The measurement results are shown in Table 1. In the case where one or more maximum and minimum peaks each having a half width of 10 nm or more do not exist in the range of 400 to 1000 nm, it is written as “x”. The ΔR of the porous silica membrane obtained above was 3.9%.

[IR spectrum of adhesive layer]
In order to confirm the type of adhesive used in the present invention, the release film of the pressure-sensitive adhesive sheet coated with the used adhesive is peeled off, and a sample is used in which the adhesive is bonded to one side of the Ge ATR prism. The IR spectrum of the adhesive was measured under the following conditions.
Measurement conditions Device: FT-IR 6100 (manufactured by JASCO Corporation)
Measurement method: ATR method Incident angle: 45 °
Detector: TGS
Accumulated frequency: 64 times [adhesive sheet]
The IR spectrum obtained above is described in Journal of Adhesion Society of Japan, 2000, vol. 36, no. 1, Fig. 19 of P19. It almost agrees with the spectrum of butyl polyacrylate of 4. By such a method, it can be determined that this adhesive is acrylic and contains butyl polyacrylate as a main component.

[Laminate production]
The pressure-sensitive adhesive sheet is formed on the above-mentioned porous silica-coated base material in which one release film of the above acrylic pressure-sensitive adhesive sheet (adhesive layer thickness: 25 μm, 20 mm square) is peeled off and the adhesive surface is cut into 20 mm square. By bonding so that the whole single side | surface of an adhesive agent surface may contact | connect a porous coating surface, the laminated body (for reflectance measurement) was obtained. In addition, the pressure-sensitive adhesive sheet is a porous silica coated substrate obtained by peeling off one surface of a release film of a pressure-sensitive adhesive sheet cut into 25 mm wide × 55 mm long and cutting it into 25 mm wide × 76 mm long The laminate A is obtained by laminating so that one of the short sides of the above and one of the short sides of the porous coated substrate overlap and the entire one side of the adhesive surface of the pressure-sensitive adhesive sheet is in contact with the porous coated surface. The Thereafter, the release film on the other side of the pressure-sensitive adhesive sheet is peeled off, and a 50 μm-thick PET film (double-sided easy-adhesion layer) cut into 25 mm width × 200 mm length is cut on the adhesive side. The laminate (for adhesive strength measurement) is laminated by laminating so that one side of the laminate A overlaps the short side of the side in contact with the pressure-sensitive adhesive sheet of the laminate A, and the entire adhesive surface contacts the PET film surface. Obtained.

[Peeling strength measurement]
The laminate (for adhesive strength measurement) was attached to a tensile tester (STA-1225 manufactured by ORIENTEC), and a 180 ° peel test was performed. The 180 ° peel test is conducted according to JIS K 6854-2, except that the size of the test piece is as described above and the peel rate is 30 mm / min, and the elongation is an average value of tensile strength between 25 and 50 mm. It was taken as adhesive strength of a pressure sensitive adhesive sheet. The adhesive strength was 4.53 N / 25 mm.

〔Environmental testing〕
The above laminate was placed in a compact environmental tester: SH-241 manufactured by ESPEC, and stored at 80 ° C. and 50% RH for 10 days.

[Peak shift]
Focus on the base material-porous membrane interface from the non-porous coated surface side of the base material of the laminate before and after the above environmental test using a spectral film thickness meter (FE-3000 manufactured by Otsuka Electronics Co., Ltd.) The reflection spectrum was measured. The peak shift was calculated from the reflection spectrum. FIG. 2 shows the reflection spectra before and after the environmental test, and Table 1 shows the results. In FIG. 2, there are one peak with lowered reflectance, one peak between 400 nm and 500 nm, and one peak between 600 nm and 700 nm, of which the peak between 600 nm and 700 nm is the reflectance The peak of 600 nm to 700 nm is the minimum reflectance peak. When the minimum reflectance peak is different before and after the environmental test, the shift amount of the minimum reflectance peak before the environmental test is considered as the magnitude of the shift of the reflection spectrum. The shift value of the reflection spectrum of Example 1 obtained in this manner was +6 nm.

[Reflectance difference of laminate]
Focus on the base material-porous membrane interface from the non-porous coated surface side of the base material of the laminate after the above environmental test using a spectral film thickness meter (manufactured by Otsuka Electronics Co., Ltd., FE-3000), The reflection spectrum was measured. The measurement results are shown in FIG. In the reflection spectrum of FIG. 1, there are two maximum peaks and two minimum peaks. The reflectance values of the maximum peaks, ie, the maximum reflectances, are listed as R _{max, 1} and R _{max, 2 in} ascending order of wavelength value, and the average value of them is the average maximum reflectance: R _{max, av} (in the case of FIG. 1) _{Rmax, av} = ( _{Rmax, 1} + _{Rmax, 2} ) / 2). Similarly, the minimum peak reflectance value, that is, the minimum reflectance is set as R _{min, 1} and R _{min, 2 in} ascending order of the wavelength value _, and the average value thereof is set as the average maximum reflectance: R _{min, av} (in the case of FIG. 1) R _{min, av} = (R _{min, 1} + R _{min, 2} ) / 2). The difference between R _{max, av} and R _{min, av} is taken as the reflectance difference: ΔR.

  ΔR was calculated from the maximum value and the minimum value of the obtained spectrum. The results are shown in Table 1. In the case where one or more maximum and minimum peaks each having a half width of 10 nm or more do not exist in the range of 400 to 1000 nm, 0% is set. The ΔR of the obtained spectrum was calculated to be 3.6%.

[Reflectance difference ratio]
The value obtained by dividing ΔR of the laminate obtained after the environmental test by ΔR of the porous coated substrate is taken as the reflectance difference ratio of the laminate. The results are shown in Table 1. When the minimum and the maximum reflectance difference of a porous coat base material were "x", it was described as "x." It was 0.88 when the reflectance difference ratio of the laminated body after the said environmental test was calculated.

[Infiltration judgment]
From the value of the reflectance ratio of the laminate after the environmental test obtained above, the penetration determination was performed based on the following criteria. The results are shown in Table 1. The penetration judgment of the laminate after the above environmental test was “◎”.
:: reflectance ratio 0.75 or more ○: reflectance ratio 0.40 or more and less than 0.75 Δ: reflectance ratio 0.20 or more and less than 0.40 ×: reflectance ratio less than 0.20 or ×
Example 2
A laminated body was manufactured by performing the same operation as in Example 1 except that an adhesive having a peeling strength of 4.77 N / 25 mm and an adhesive layer thickness of 20 μm was used, and each evaluation was performed. The results are shown in Table 1.

[Example 3]
A laminated body was manufactured by performing the same operation as in Example 1 except that the peel strength: 11.46 N / 25 mm and the adhesive layer thickness: 25 μm were used, and each evaluation was performed. The results are shown in Table 1.
Example 4
A laminate was manufactured by performing the same operation as in Example 1 except that an adhesive having a peeling strength of 11.84 N / 25 mm and an adhesive layer thickness of 20 μm was used, and each evaluation was performed. The results are shown in Table 1.

[Example 5]
A laminate was manufactured in the same manner as in Example 1 except that the rotation speed of the spin coater was set to 500 rpm, an adhesive having a peel strength of 6.84 N / 25 mm, and an adhesive layer thickness of 52 μm was used. Each evaluation was done. The results are shown in Table 1.
The adhesives used in Examples 1-5 are all called adhesive.

Comparative Example 1
A laminated body was manufactured by performing the same operation as in Example 1 except that the rotation speed of the spin coater was 1500 rpm, and the adhesive sheet having a peeling strength of 15.31 N / 25 mm and an adhesive layer thickness of 20 μm was used. Each evaluation was done. The results are shown in Table 1.

  From these results, the laminate of the present invention adheres the other members onto the adhesive layer while maintaining low refractive index and little penetration of the adhesive from the adhesive layer in the porous layer. I know that I can do it.

  According to the present invention, it is possible to obtain a laminate that can be used by pasting other components and the like on a mesoporous porous layer utilizing a low refractive index.

Claims (6)

Peeling strength measured at a peeling speed of 30 mm / min in a 180 ° peel test of a laminate comprising a mesoporous silica porous layer containing no organic polymer and an adjacent adhesive layer Is in the range of 0.05 N / 25 mm or more and 14 N / 25 mm or less, and the value of the shift of the reflection spectrum before and after the endurance test for 10 days at 80 ° C. and 50% RH is −
A laminate having a thickness of 30 nm or more and 200 nm or less.   The layered product according to claim 1 whose thickness of said adhesion layer is 5 micrometers or more and 100 micrometers or less. The laminate according to any one of claims 1 and 2, wherein the adhesive layer contains an acrylic resin. Laminate according to any one of claims 1 to 3 the refractive index of the mesoporous silica porous layer which does not contain the organic polymer is 1.30 or less. Laminate according to any one of claims 1 to 4, characterized in that mesoporous silica porous layer which does not contain the organic polymer is adjacent to the refractive index of 1.40 or more other layers. It is a manufacturing method of the layered product according to any one of claims 1 to 5,
A set including hydrolyzate and partial condensate of alkoxysilane, water, organic solvent, organic polymer
Applying the composition on a substrate to form a layer of a silica-based precursor film;
A porous silica membrane is formed through the step of removing the organic polymer from the silica-based precursor membrane
Create
An adhesive layer is provided on the whole or a specific area on the porous silica membrane.
Method of manufacturing a laminate.

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