JP5640310B2 - Composition, antireflection film substrate, and solar cell system - Google Patents

Description

  The present invention relates to a composition containing a silicon compound, an antireflection film substrate using the same, and a solar cell system.

  Various techniques of porous silica films as low refractive index materials have been reported. For example, in Patent Documents 1 to 5, a specific organic substance is allowed to coexist in the sol-gel reaction of alkoxysilane to form a silica / organic substance-hybrid, and then the organic substance is removed, whereby uniform and regular. A method for obtaining a porous silica material having pores is disclosed.

JP 2001-226171 A JP 2003-64307 A JP 2003-142476 A JP 2004-143029 A JP 2005-503664 A

However, the composition for forming a porous silica material obtained by the techniques described in Patent Documents 1 to 5 has a short pot life, and it is often difficult to obtain a porous silica material stably.
Conventionally, many porous silica materials have been developed as low dielectric constant materials. In particular, Patent Document 5 discloses weak mechanical strength of porous silica materials and changes in dielectric constant (refractive index) caused by water vapor. Is described as an issue. Patent Document 5 indicates that this problem can be solved by blending a specific alkoxysilane at a specific ratio in order to reduce the change in dielectric constant (refractive index) with respect to water vapor. Specifically, a hydrophobic silica film made from triethoxysilane: methyltriethoxysilane = 1: 1 is shown as a composition whose refractive index does not change or is small with respect to relative humidity changes. However, in the examples in Patent Document 5, the hydrophobic silica film has a small refractive index change over a wide range of relative humidity, but the refractive index does not change even when the relative humidity change is 0.8 or more. The absolute value of is large (1.25 or more). For example, when it is applied and produced on a glass substrate, a sufficient antireflection effect may not be obtained.

  Further, for example, Patent Document 3 and the like have reported various types of porous silica materials characterized by having a regular pore structure from the viewpoint of lowering the refractive index and improving the film strength. In Patent Document 3, in the X-ray scattering measurement of the porous silica, at least one scattering peak is present between the scattering angle (2θ) of 0.5 ° to 3 °, so that the mechanical strength is high. It has been reported that a porous silica material can be obtained. However, in such a film, since the pores have a regular structure, the distortion in the film is large, and the amount of tetraalkoxysilane in the coating composition for obtaining the film is large. It is considered that the silanol group of the reaction tends to remain, which becomes a hydrophilic site and increases the water vapor adsorption amount.

  Moreover, in the composition for forming a silica porous material described in Patent Document 1 and Patent Document 5, a silica porous material having a very hydrophobic film surface can be obtained. However, since the amount of water relative to alkoxysilane is small, It is also conceivable that unreacted alkoxy groups remain, this part becomes a hydrophilic part, and the amount of water vapor adsorption increases.

  In addition, in the composition for forming a porous silica material described in Patent Document 2, the amount of water adsorbed and the amount of water vapor adsorbed increase as the molecular weight of the organic material used is low and the firing under inert conditions is necessary. Conceivable. Moreover, it is difficult to maintain the porosity of the obtained silica porous body high, and there is a possibility that a low refractive index silica porous body cannot be stably produced.

  Furthermore, in the composition for forming a porous silica material described in Patent Document 4, since the molecular weight of the organic material used is low and the amount of the organic material used is large, the resulting porous silica material has small pores, resulting in silica. It is considered that the amount of water vapor adsorption increases because the surface area of the porous body increases and the hydrophilic portion increases.

  The present invention was devised in view of the above problems, and a silicon compound having a sufficiently low refractive index and stable against water vapor, that is, capable of producing a silica film with little change in refractive index even in a wide range of relative humidity. It is an object of the present invention to provide a composition containing the same, an antireflection film substrate using the composition, and a solar cell system.

  As a result of intensive studies by the present inventors to solve the above-mentioned problems, the refractive index of a film obtained by applying and baking a composition containing a silicon compound is not more than a predetermined value. When the powder obtained by baking after air drying has a difference in water vapor adsorption amount at a predetermined relative water vapor pressure of a predetermined value or less, the refractive index of the silica film formed using the composition is sufficiently low, and further the water vapor stability The present invention was completed.

That is, the gist of the present invention is that at least one selected from the group of tetraalkoxysilanes consisting of tetraalkoxysilanes, hydrolysates and partial condensates thereof, and alkoxysilanes other than the tetraalkoxysilanes, hydrolysates thereof, and At least one combination selected from another alkoxysilane group consisting of a partial condensate, and / or at least one partial condensate selected from at least one selected from the tetraalkoxysilane group and other alkoxysilane groups, and A composition containing a silicon compound, comprising water, an organic solvent, and a nonionic polymer having an ethylene oxide moiety, wherein the ratio of water to silicon atoms derived from all alkoxysilanes is 10 (mol / mol) or more. The composition is applied to a substrate and is at least 400 ° C. The film obtained by baking at 450 ° C. or lower for 1 minute or longer and 1 hour or shorter has a refractive index of 1.25 or lower, and the composition is air-dried at room temperature and a relative humidity of 40% for 3 days. Then, the water vapor adsorption amount at a relative water vapor pressure of 0.3 <P / P ₀ <0.9 at 25 ° C. of the powder obtained by baking at 400 ° C. or higher and 450 ° C. or lower for 1 minute or longer and 5 hours or shorter. It exists in the composition characterized by the difference (DELTA) being 0.03 g / g or less (Claim 1). (Here, P is the water vapor partial pressure at 25 ° C., and P ₀ is the saturated water vapor pressure at 25 ° C.)

The composition preferably further comprises a catalytic (claim 2).

The nonionic polymer having an ethylene oxide moiety preferably has a weight average molecular weight of 4,300 or more.
Further, the ratio of silicon atoms derived from tetraalkoxysilanes to silicon atoms derived from all alkoxysilanes is preferably 0.3 (mol / mol) to 0.7 (mol / mol). ).

Further, 80% by weight or more of the organic solvent is preferably an organic solvent having a boiling point of 55 ° C. or higher and 140 ° C. or lower ( Claim 5 ).
The ratio of the nonionic polymer having the ethylene oxide moiety to the silicon atoms derived from all alkoxysilanes is preferably 0.001 (mol / mol) or more and 0.05 (mol / mol) or less ( claims). 6 ).
Non ionic polymer having the ethylene oxide moiety, it is preferable that the content of the ethylene oxide moiety is 20 wt% or more (claim 7).

Further, the nonionic polymer having an ethylene oxide moiety is preferably at least one nonionic polymer selected from the group consisting of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer and polyethylene glycol ( 8.) a said tetraalkoxysilane is tetraethoxysilane, alkoxysilanes other than the tetraalkoxysilanes are monoalkyl alkoxysilane or dialkyl alkoxysilane having an aromatic hydrocarbon group or an aliphatic hydrocarbon group ( Claim 9 ).
Also, the organic solvent is ethanol, 1-propanol, t-butanol, 2-propanol, 1-butanol, 1-preferably contains at least one pentanol and selected from the group consisting of ethyl acetate (claim 10 ).

Another gist of the present invention resides in an antireflection film substrate comprising a thin film obtained by heat-treating any of the above compositions on a base material ( claim 11 ).
Still another subject matter of the present invention lies in a solar cell system comprising the antireflection film substrate on the light receiving surface side ( claim 12 ).

  Hereinafter, the present invention will be described in detail with reference to embodiments, examples, etc., but the present invention is not limited to the following embodiments, examples, etc., and may be arbitrarily selected without departing from the gist of the present invention. You can change it to

1. Composition The composition of the present invention contains a silicon compound and further satisfies the following conditions (1) and (2).
(1) The refractive index of the film obtained by applying the composition on a substrate and baking it at 400 ° C. or higher and 450 ° C. or lower for 1 minute or longer and 1 hour or shorter is 1.25 or lower.
(2) The powder obtained by air-drying the composition at room temperature under a relative humidity of 40% for 3 days and then firing at 400 ° C. or higher and 450 ° C. or lower for 1 minute or longer and 5 hours or shorter at 25 ° C. The difference in water vapor adsorption Δ at a relative water vapor pressure of 0.3 <P / P ₀ <0.9 is 0.03 g / g or less. (Here, P is the water vapor partial pressure at 25 ° C., and P ₀ is the saturated water vapor pressure at 25 ° C.)

  Since the composition of the present invention has the above-mentioned condition (2), that is, the water vapor adsorption amount difference Δ is not more than the above value within a predetermined relative water vapor pressure range, The environmental stability such as the rate and the optical film thickness can be improved.

  Moreover, since the composition of this invention satisfy | fills the conditions (1) and (2) mentioned above, while being able to maintain a low refractive index, it is excellent in humidity stability. It is surmised that this excellent humidity stability can be realized by reducing the moisture adsorption to the surface by making the composition of the present invention a superhydrophobic composition.

Moreover, since the composition of this invention satisfy | fills the conditions (1) and (2) mentioned above, it can make the stability of the silica film produced using a composition high. Specifically, it is possible to produce a silica film having stable optical characteristics such as little change in refractive index over time, transparency can be maintained, and cracks do not occur.
Hereinafter, the conditions (1) and (2) will be described in detail.

1-1. Condition (1)
The composition of the present invention has a refractive index of a film obtained by baking the composition at 400 ° C. or higher and 450 ° C. or lower for 1 minute or longer and 1 hour or shorter after applying the composition on a substrate. . The refractive index is preferably 1.23 or less, and particularly preferably 1.20 or less. When the refractive index is too large, the antireflection effect of the silica film produced using the composition of the present invention is reduced, and it is difficult to obtain the effect as a low refractive index film. On the other hand, the lower limit of the refractive index is not particularly limited, but is usually 1.05 or more, preferably 1.08 or more.

  Reducing the refractive index of a silica film produced using the composition of the present invention is achieved by forming voids by pores. If the refractive index is too small, that is, if there are too many voids, the silica film machine Strength may be significantly reduced. The refractive index refers to a value at a wavelength of 400 nm to 700 nm measured by an optical technique such as a spectroscopic ellipsometer method, reflectance measurement, or prism coupler, and is preferably measured by a spectroscopic ellipsometer. When measuring with a spectroscopic ellipsometer, the refractive index can be calculated by fitting the measured value with a Cauchy model.

  In addition, when a film is produced on a substrate having a large center line average roughness, the refractive index can be calculated also by reflectance spectral measurement, and in this case, the measurement region is preferably 10 μm or less. .

1-2. Condition (2)
Another feature of the composition of the present invention is the water vapor adsorption property of a powder obtained by air-drying the composition under predetermined conditions and then firing. A silica film produced by a normal sol-gel method tends to change its hydrophilicity with a change in humidity due to the influence of unreacted alkoxide or silanol groups on the generated gel surface. That is, when the water vapor adsorption characteristic is measured, the water vapor adsorption amount increases as the relative water vapor pressure increases.
However, when a silica film is formed on a substrate and used as a low refractive index film for antireflection applications, for example, water vapor adsorption may cause an increase in the refractive index, making it impossible to obtain an antireflection effect. There is sex. Therefore, when a silica film is used as a low refractive index antireflection film, it is preferable that the hydrophilicity is stable against changes in humidity.

The composition of the present invention is a powder obtained by air-drying the composition at room temperature under a relative humidity of 40% for 3 days and then calcining at 400 to 450 ° C. for 1 to 5 hours. The difference in water vapor adsorption Δ at a relative water vapor pressure of 0.3 <P / P ₀ <0.9 at 25 ° C. is usually 0.03 g / g or less, preferably 0.02 g / g or less. When the water vapor adsorption amount difference Δ is larger than the above value in the relative water vapor pressure range, not only the refractive index changes but also the film may be cracked or the surface may be roughened. It may not be obtained. Here, P is a water vapor partial pressure at 25 ° C., and P ₀ is a saturated water vapor pressure at 25 ° C.

Specifically, the water vapor adsorption amount difference Δ can be measured in the following manner.
The composition of the present invention is poured into a petri dish, air-dried at room temperature under a relative humidity of 40 ° C. for 3 days, scraped off with a metal spoon to form a powder, and further in a muffle furnace in the atmosphere at a predetermined temperature (400 ° C. As described above, silica powder from which organic substances have been removed can be obtained by heat treatment at 450 ° C. or lower for a predetermined time (1 minute to 5 hours). This powder, varying the relative humidity P / P _0, the water vapor standard adsorption amount at equilibrium can be determined by the volume method or gravimetric method. In general, a capacitance method is used. As an apparatus used for the capacity method, for example, Bell Soap 18 manufactured by Nippon Bell Co., Ltd. may be mentioned.

1-3. Composition of Composition of the Present Invention The composition of the present invention is not particularly limited as long as it contains a silicon compound and can satisfy the above conditions (1) and (2). At least one selected from the group consisting of silanes, tetraalkoxysilanes composed of hydrolysates and partial condensates thereof, and other alkoxysilanes composed of alkoxysilanes other than the tetraalkoxysilanes, hydrolysates and partial condensates thereof A combination of at least one selected from and / or at least one partial condensate selected from at least one selected from the group of tetraalkoxysilanes and other alkoxysilanes, water, an organic solvent, and a catalyst, It preferably contains a nonionic polymer having an ethylene oxide moiety. Furthermore, the composition of the composition preferably satisfies the following conditions (3) to (6).

(3) The ratio of silicon atoms derived from tetraalkoxysilanes to silicon atoms derived from all alkoxysilanes is 0.3 (mol / mol) or more and 0.7 (mol / mol) or less.
(4) The ratio of water to silicon atoms derived from all alkoxysilanes is 10 (mol / mol) or more.
(5) The weight average molecular weight of the nonionic polymer having an ethylene oxide moiety is 4,300 or more.
(6) 80% by weight or more of the organic solvent is a solvent having a boiling point of 55 ° C. or higher and 140 ° C. or lower.

1-3-1. Alkoxysilanes The composition of the present invention preferably contains an alkoxysilane as a silicon compound, and the alkoxysilane contains any one or both of the following first and second compounds (groups). It is preferable to do.

[First Compound (Group)]
At least one selected from the group of tetraalkoxysilanes (ie, a group consisting of tetraalkoxysilanes, hydrolysates and partial condensates thereof), and another group of alkoxysilanes (ie, other alkoxysilanes, hydrolysates thereof, and A combination with at least one selected from the group consisting of partial condensates.
[Second compound (group)]
A specific partial condensate (that is, a partial condensate of at least one selected from the tetraalkoxysilane group and at least one selected from the other alkoxysilane group).

-Tetraalkoxysilane group There is no restriction | limiting in particular in the kind of tetraalkoxysilane contained in the tetraalkoxysilane group. Examples of suitable tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetra (n-propoxy) silane, tetraisopropoxysilane, tetra (n-butoxy) silane and the like. Examples of the tetraalkoxysilane group include hydrolysates and partial condensates (such as oligomers) of the above tetraalkoxysilanes. Among them, from the viewpoint of stability and productivity of the composition of the present invention, tetramethoxysilane and tetraethoxysilane and oligomers thereof are preferable, and tetraethoxysilane is more preferable. However, since tetraalkoxysilanes tend to undergo hydrolysis and partial condensation over time, even when only tetraalkoxysilanes are prepared, the hydrolysates and partial condensates of tetraalkoxysilanes are usually tetraalkoxysilanes. Often co-exists with other species. In addition, the compound which belongs to the tetraalkoxysilane group may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

-Other alkoxysilanes group Any other alkoxysilanes can be used as long as they are alkoxysilanes that do not belong to the tetraalkoxysilanes described above. Examples of suitable ones include trialkoxysilanes such as trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane Dialkoxysilanes such as diphenyldimethoxysilane and diphenyldiethoxysilane; bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane, 1,2-bis (trimethoxysilyl) ethane, 1,2-bis ( 2 organic residues such as triethoxysilyl) ethane, 1,4-bis (trimethoxysilyl) benzene, 1,4-bis (triethoxysilyl) benzene, 1,3,5-tris (trimethoxysilyl) benzene One or more trialkoxysilyl groups Bonded; 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-acryloyl And those having an alkyl group substituted with a silicon atom, such as loxypropyltrimethoxysilane and 3-carboxypropyltrimethoxysilane, having a reactive functional group. Examples of other alkoxysilane groups include hydrolysates and partial condensates (such as oligomers) of the other alkoxysilanes.

  Of these, monoalkylalkoxysilanes and dialkylalkoxysilanes having an aromatic hydrocarbon group or an aliphatic hydrocarbon group are preferred. Specific examples include methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, and dimethyldiethylsilane. However, since other alkoxysilanes tend to undergo hydrolysis and partial condensation over time, even when only other alkoxysilanes are prepared, other alkoxysilane hydrolysates and partial condensates are usually other. Often coexists with other alkoxysilanes. In addition, the compound which belongs to other alkoxysilanes may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

・ Specific partial condensates (partial condensates of tetraalkoxysilanes and other alkoxysilanes)
Any specific condensate may be used as long as it is a partial condensate obtained by partial condensation of at least one selected from the above-described tetraalkoxysilane group and at least one selected from another alkoxysilane group. When a suitable example is given, the partial condensate which the thing illustrated as a suitable example of tetraalkoxysilane and the thing illustrated as a suitable example of another alkoxysilane will be mentioned. In addition, the specific partial condensate may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio. The specific partial condensate may be used alone or in combination with one or both of the above-mentioned tetraalkoxysilanes and other alkoxysilanes.

Preferred combinations Among the combinations of tetraalkoxysilanes and other tetraalkoxysilanes described above, particularly preferred combinations include tetraethoxysilane as tetraalkoxysilanes and aromatic hydrocarbon groups as other alkoxysilanes. Or the combination with the monoalkyl alkoxysilane or dialkyl alkoxysilane which has an aliphatic hydrocarbon group is mentioned. According to this combination, a composition satisfying the above conditions (1) and (2) can be easily obtained.

-Ratio of alkoxysilanes In the composition of the present invention, the alkoxysilanes described above preferably satisfy the above condition (3). That is, the ratio of silicon atoms derived from tetraalkoxysilanes to silicon atoms derived from all alkoxysilanes is usually 0.3 (mol / mol) or more, preferably 0.35 (mol / mol) or more, more preferably 0. .4 (mol / mol) or more, and usually 0.7 (mol / mol) or less, preferably 0.65 (mol / mol) or less, more preferably 0.6 (mol / mol) or less. When the ratio is too small, the hydrophobicity of the silica film obtained from the composition is increased, but the mechanical strength of the silica film is extremely weak due to the decrease in —O—Si—O— bonds, The humidity resistance stability also tends to decrease. On the other hand, when the ratio is too large, the residual silanol groups in the silica film increase, and the humidity resistance stability tends to decrease.

  Here, the silicon atoms derived from all alkoxysilanes refer to the total number of silicon atoms contained in the tetraalkoxysilane group, other alkoxysilane groups and the specific partial condensate contained in the composition of the present invention. Moreover, the silicon atom derived from tetraalkoxysilane corresponds to the number of silicon atoms contained in the tetraalkoxysilane group contained in the composition of the present invention and the tetraalkoxysilane group among silicon atoms contained in the specific partial condensate. And the total number of silicon atoms belonging to the partial structure.

  Therefore, even if the composition of the present invention contains a compound having a silicon atom in addition to the alkoxysilanes, the silicon atom contained in the compound is not involved in the calculation of the ratio. In addition, the ratio of the silicon atom derived from tetraalkoxysilane to the silicon atom derived from all the alkoxysilanes can be measured by Si-NMR.

  In the composition of the present invention, the silicon-containing compound (silicon atom-containing compound) is usually 0.05% by weight or more, preferably 0.1% by weight or more, more preferably 0.5% by weight or more. It is preferably contained in an amount of 1% by weight or more, and is usually 70% by weight or less, preferably 50% by weight or less, more preferably 40% by weight or less, and further preferably 20% by weight or less. . If it is less than 0.05% by weight, the film-forming property such as film thickness unevenness may be lowered, and if it exceeds 70% by weight, the stability of the composition may be lowered. Specific examples of the silicon atom-containing compound include the aforementioned tetraalkoxysilane group, other alkoxysilane groups, and a specific partial condensate.

  Further, from the viewpoint of the production process of the silica porous body, that is, the silica film produced from the composition of the present invention, the solid content concentration containing the silicon atom-containing compound and the nonionic polymer described below is usually 0. .1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more. Further, it is usually preferably 50% by weight or less, more preferably 40% by weight or less, and further preferably 35% by weight or less.

  Moreover, it is preferable that pH of a composition is 5.5 or less from a viewpoint of film forming property. More preferably, it is 4.5 or less, More preferably, it is 3 or less, Most preferably, it is 2 or less. By making it in this range, the surface modification of the substrate can be performed at the same time during film formation, and the film-forming property tends to be further improved.

1-3-2. Water The composition of the present invention preferably contains water, and the purity of the water used is preferably higher. Usually, water subjected to either or both of ion exchange and distillation may be used. However, it is preferable that the amount of water used satisfies the above condition (4). That is, the ratio of water to silicon atoms derived from all alkoxysilanes is usually 10 (mol / mol) or more, preferably 11 (mol / mol) or more, more preferably 12 (mol / mol) or more. If the ratio of water to silicon atoms derived from all alkoxysilanes is smaller than the above value, it is difficult to control the sol-gel reaction, the pot life is short, and a silica film having a very hydrophilic surface may be obtained. . For this reason, the humidity resistance stability of the silica film produced from the composition of the present invention tends to be low. The amount of water can be calculated by the Karl Fischer method (coulometric titration method).

1-3-3. Organic Solvent The composition of the present invention preferably contains an organic solvent. As for the kind of the organic solvent, it is preferable to use a solvent having a boiling point of 55 ° C. or more and 140 ° C. or less at the above condition (6), that is, 80% by weight or more in the organic solvent. Among these, as the organic solvent, it is preferable to use one or more organic silanes having the ability to mix the alkoxysilanes and water described above.

  Examples of suitable organic solvents include C1-C4 monohydric alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, Alcohols such as polyhydric alcohols such as dihydric alcohols having 1 to 4 carbon atoms, glycerin and pentaerythritol; diethylene glycol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, 2-ethoxyethanol, propylene glycol monomethyl ether, propylene glycol methyl ether acetate Ethers or esterified products of the above alcohols; ketones such as acetone and methyl ethyl ketone; formamide, N-methylformamide, N-ethylformamide, N, N-dimethylphenol Muamide, N, N-diethylformamide, N-methylacetamide, N-ethylacetamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone, N-formylmorpholine, N-acetylmorpholine, N- Amides such as formylpiperidine, N-acetylpiperidine, N-formylpyrrolidine, N-acetylpyrrolidine, N, N′-diformylpiperazine, N, N′-diformylpiperazine, N, N′-diacetylpiperazine; Lactones such as butyrolactone; ureas such as tetramethylurea and N, N′-dimethylimidazolidine; dimethylsulfoxide and the like.

  Among these, alcohols are preferable and monohydric alcohols are more preferable for the contained alkoxysilanes to perform hydrolysis under more stable conditions. In addition, only 1 type may be used for an organic solvent and it may use 2 or more types together by arbitrary combinations and a ratio. Among these, in order to more reliably obtain a silica film having a low refractive index and excellent humidity stability using the composition of the present invention, it is possible to use a mixture of two or more organic solvents as the organic solvent. Preferably, in order to form a homogeneous silica film by heat treatment, it is preferable that a certain degree of curing (condensation reaction of alkoxysilanes) and water removal are simultaneously performed during the heat treatment. Accordingly, it is preferable to use an organic solvent in which the organic solvent in the composition of the present invention is volatilized in a temperature range in which moisture existing near or inside the surface can be removed to some extent.

  For this reason, the composition of the present invention preferably contains an organic solvent having a boiling point in a predetermined range as an organic solvent at a predetermined high ratio, and preferably satisfies the above condition (6). . Specifically, an organic solvent having a boiling point of usually 55 ° C. or higher, preferably 60 ° C. or higher, more preferably 65 ° C. or higher, and usually 140 ° C. or lower, preferably 135 ° C. or lower, more preferably 130 ° C. or lower. , "Referred to as" predetermined boiling point solvent "), and the ratio of the predetermined boiling point solvent in the total organic solvent is usually 80% by weight or more, preferably 83% by weight or more, more preferably 85% by weight or more. To do.

  The upper limit of the ratio is 100% by weight. If the boiling point is too low, the composition is cured with insufficient sol-gel reaction, and the humidity resistance stability of the silica film produced using the composition of the present invention may be extremely low. On the other hand, if the boiling point is too high, the sol-gel reaction proceeds locally and the silica film becomes inhomogeneous, which may lead to a decrease in surface properties and a decrease in humidity stability. Furthermore, when the ratio of the predetermined boiling point solvent is low, the above advantages may not be obtained. From this point of view, preferable examples of the predetermined boiling point solvent include ethanol, 1-propanol, t-butanol, 2-propanol, 1-butanol, 1-pentanol, and ethyl acetate. Therefore, it is preferable to use at least one selected from these as the organic solvent.

  Moreover, the usage-amount of the whole organic solvent is arbitrary unless the effect of this invention is impaired remarkably. However, with respect to the silicon atoms derived from all alkoxysilanes, usually 0.01 mol / mol or more, particularly 0.1 mol / mol or more, particularly 1 mol / mol or more is preferable, and usually 100 mol / mol or less, particularly 70 mol / mol. It is preferably not more than mol, particularly not more than 20 mol / mol. If the amount of organic solvent used is too small, the surface properties of the silica film produced from the composition may be reduced. If it is too large, the film quality will be affected by the surface energy of the substrate when it is formed as a silica film on the substrate. May be easier.

1-3-4. Catalyst The composition of the present invention preferably contains a catalyst. As the catalyst, a substance that promotes the hydrolysis and dehydration condensation reaction of the above-mentioned alkoxysilanes can be arbitrarily used. Examples include acids such as hydrochloric acid, nitric acid, sulfuric acid, formic acid, acetic acid, oxalic acid and maleic acid; amines such as ammonia, butylamine, dibutylamine and triethylamine; bases such as pyridine; acetylacetone complexes of aluminum, etc. Lewis acids; and the like. Moreover, a metal chelate compound is also mentioned as an example of a catalyst. Examples of the metal species of the metal chelate compound include titanium, aluminum, zirconium, tin, and antimony. Specific examples of the metal chelate compound include the following.

  Examples of the aluminum complex include di-ethoxy mono (acetylacetonato) aluminum, di-n-propoxy mono (acetylacetonato) aluminum, di-isopropoxy mono (acetylacetonato) aluminum, di-n- Butoxy mono (acetylacetonato) aluminum, di-sec-butoxy mono (acetylacetonato) aluminum, di-tert-butoxy mono (acetylacetonato) aluminum, monoethoxy bis (acetylacetonato) aluminum, mono -N-propoxy bis (acetylacetonato) aluminum, monoisopropoxy bis (acetylacetonato) aluminum, mono-n-butoxy bis (acetylacetonato) aluminum, mono-sec-but Si-bis (acetylacetonato) aluminum, mono-tert-butoxy bis (acetylacetonato) aluminum, tris (acetylacetonato) aluminum, diethoxy mono (ethylacetoacetate) aluminum, di-n-propoxy mono ( Ethyl acetoacetate) aluminum, diisopropoxy mono (ethyl acetoacetate) aluminum, di-n-butoxy mono (ethyl acetoacetate) aluminum, di-sec-butoxy mono (ethyl acetoacetate) aluminum, di-tert- Butoxy mono (ethyl acetoacetate) aluminum, monoethoxy bis (ethyl acetoacetate) aluminum, mono-n-propoxy bis (ethyl acetoacetate) aluminum, mono Sopropoxy bis (ethyl acetoacetate) aluminum, mono-n-butoxy bis (ethyl acetoacetate) aluminum, mono-sec-butoxy bis (ethyl acetoacetate) aluminum, mono-tert-butoxy bis (ethyl acetoacetate) Examples thereof include aluminum chelate compounds such as aluminum and tris (ethylacetoacetate) aluminum.

  Examples of the titanium complex include triethoxy mono (acetylacetonato) titanium, tri-n-propoxy mono (acetylacetonato) titanium, triisopropoxy mono (acetylacetonato) titanium, tri-n-butoxy mono ( Acetylacetonato) titanium, tri-sec-butoxy mono (acetylacetonato) titanium, tri-tert-butoxy mono (acetylacetonato) titanium, diethoxybis (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 Acetyl acetonato) titanium, monoethoxy tris (acetyl acetonato) titanium, mono-n-propoxy tris (acetyl acetonato) titanium, monoisopropoxy tris (acetyl acetonato) titanium, mono-n-butoxy tris (Acetylacetonato) titanium, mono-sec-butoxy tris (acetylacetonato) titanium, mono-tert-butoxy tris (acetylacetonato) titanium, tetrakis (acetylacetonato) titanium, triethoxy mono (ethylacetoacetate) ) Titanium, tri-n-propoxy mono (ethyl acetoacetate) titanium, triisopropoxy mono (ethyl acetoacetate) titanium, tri-n-butoxy mono (ethyl acetoacetate) titanium, tri-se -Butoxy mono (ethyl acetoacetate) titanium, tri-tert-butoxy mono (ethyl acetoacetate) titanium, diethoxy bis (ethyl acetoacetate) titanium, di-n-propoxy bis (ethyl acetoacetate) titanium, di Isopropoxy bis (ethyl acetoacetate) titanium, di-n-butoxy bis (ethyl acetoacetate) titanium, di-sec-butoxy bis (ethyl acetoacetate) titanium, di-tert-butoxy bis (ethyl acetoacetate) ) Titanium, monoethoxy tris (ethyl acetoacetate) titanium, mono-n-propoxy tris (ethyl acetoacetate) titanium, monoisopropoxy tris (ethyl acetoacetate) titanium, mono-n-butoxy tris (ethyl) Acetoacetate) titanium, mono-sec-butoxy tris (ethyl acetoacetate) titanium, mono-tert-butoxy tris (ethyl acetoacetate) titanium, tetrakis (ethyl acetoacetate) titanium, mono (acetylacetonate) tris (ethyl) Acetoacetate) titanium, bis (acetylacetonato) bis (ethylacetoacetate) titanium, tris (acetylacetonato) mono (ethylacetoacetate) titanium and the like.

  Among those described above, acids or metal chelate compounds are preferable and acids are more preferable in order to more easily control the hydrolysis and dehydration condensation reaction of alkoxysilanes. In addition, a catalyst may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio. The amount of the catalyst used is arbitrary as long as the effects of the present invention are not significantly impaired. However, it is usually 0.001 mol times or more, especially 0.003 mol times or more, particularly preferably 0.005 mol times or more, and usually 0.8 mol times or less, especially 0.5 mol times or less, especially with respect to alkoxysilanes. Is preferably 0.1 mol times or less. If the amount of the catalyst used is too small, the hydrolysis reaction will not proceed moderately, and active groups such as silanol groups are likely to remain in the silica film produced from the composition, which may reduce the water resistance of the silica film. is there. Moreover, when too large, reaction control will become difficult and the surface property of the silica membrane produced may fall because catalyst concentration becomes still higher during manufacture.

1-3-5. Nonionic Polymer The composition of the present invention preferably contains a nonionic polymer having an ethylene oxide moiety (hereinafter also referred to as “nonionic polymer according to the present invention” as appropriate). However, the nonionic polymer according to the present invention preferably satisfies the above condition (5). That is, the weight average molecular weight of the nonionic polymer according to the present invention is usually 4,300 or more, preferably 5,000 or more, and more preferably 6,000 or more. If the weight average molecular weight of the nonionic polymer according to the present invention is too small, it is difficult to maintain a high porosity of the silica film produced from the composition, and a low refractive index silica film is stably produced. May not be possible. The upper limit of the weight average molecular weight is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 100,000 or less, preferably 70,000 or less, more preferably 40,000 or less. If the weight average molecular weight is too large, there is a tendency that a homogeneous silica film cannot be produced from the composition. Therefore, both the refractive index and humidity resistance stability tend to decrease. In addition, the nonionic polymer according to the present invention has an ethylene oxide moiety, so that it is stable against a hydrolyzate or condensate of alkoxysilanes formed during the sol-gel reaction of alkoxysilanes. . At this time, the content of the ethylene oxide moiety in the nonionic polymer according to the present invention is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 20% by weight or more, preferably 23% by weight or more. Preferably it is 25 weight% or more, and is 100 weight% or less normally, Preferably it is 90 weight% or less, More preferably, it is 85 weight% or less. By keeping the content of the ethylene oxide moiety within the above range, the nonionic polymer is more stable against the hydrolyzate or condensate of alkoxysilanes formed during the sol-gel reaction of alkoxysilanes. Can exist.

  The nonionic polymer according to the present invention preferably has an ethylene oxide moiety and satisfies the above condition (5), and the main chain skeleton structure is not particularly limited as long as it is a nonionic polymer. Absent. Specific examples of the main chain skeleton structure include polyether, polyester, polyurethane, polyolefin, polycarbonate, polydiene, polyvinyl ether, polystyrene, and derivatives thereof. Among these, a polymer containing a polyether as a constituent component is preferable. Specific examples thereof include polyethylene glycol (hereinafter referred to as “PEG” as appropriate), polypropylene glycol, polyisobutylene glycol, and the like. Among these, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer and / or polyethylene glycol are particularly preferable. In addition, the nonionic polymer concerning this invention may use only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. Moreover, the usage-amount of the nonionic polymer which concerns on this invention is arbitrary unless the effect of this invention is impaired remarkably. However, the ratio of the nonionic polymer according to the present invention to silicon atoms derived from all alkoxysilanes is usually 0.001 (mol / mol) or more, preferably 0.002 (mol / mol) or more, more preferably 0.003 (mol / mol) or more, usually 0.05 (mol / mol) or less, preferably 0.04 (mol / mol) or less, more preferably 0.03 (mol / mol) or less. To. If the ratio is too small, not only the stability of the composition of the present invention is lowered, but also the produced silica film cannot form a sufficient porous structure, and a low refractive index may not be realized. is there. On the other hand, when the ratio is too large, excessive nonionic polymer may be separated and precipitated in the composition, and the composition may not be uniform.

1-3-6. Others As long as it is possible to produce a composition satisfying the above conditions (1) and (2), the composition of the present invention includes the alkoxysilanes, water, organic solvent, catalyst, and Components other than the ionic polymer may be contained. Moreover, the said component may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

1-4. Advantages of the composition of the present invention The composition of the present invention is capable of producing a silica film having a low refractive index and excellent humidity stability. A specific method for producing the antireflection film of the antireflection film substrate using the composition of the present invention will be described later. Further, since the composition of the present invention has a long pot life and is stable, a silica film having a sufficiently low refractive index can be produced stably as compared with the prior art.

1-5. Uses of the composition of the present invention The silica film produced using the composition of the present invention has a low refractive index, and the refractive index can be controlled within a desired range. Can be applied. Moreover, since the silica film (low refractive index film) produced by the composition of the present invention is excellent in smoothness, it is expected to be applied as, for example, a light extraction material in an electroluminescence element. Furthermore, the silica film (low refractive index film) produced by the composition of the present invention is stable against changes in humidity and can be used for applications presumed to be used outdoors. For example, solar cell systems and building materials It can also be applied to automobile interior and exterior. Specifically, the silica film produced from the composition of the present invention can be suitably used as a solar cell low reflective layer or the like. This low reflection layer for solar cells is usually formed on the outermost surface of the solar cell system and functions as a light capturing film. That is, the low reflection layer for a solar cell functions to efficiently take in the light incident on the solar cell and increase the power generation efficiency of the solar cell.
In addition, the use of the composition of this invention is not limited to the said use.

2. Antireflection Film Substrate The antireflection film substrate of the present invention is characterized by comprising a thin film obtained by applying the above-described composition of the present invention to a substrate and then heat-treating it. The antireflection film substrate comprises a thin film obtained by heat-treating the above composition, that is, a silica film having a low refractive index and excellent humidity stability. Therefore, for example, it is very useful as an antireflection film substrate in a solar cell system described later. In addition to the base material and the thin film (silica film) produced using the composition, the antireflection film substrate of the present invention may be appropriately provided with other members as necessary.

2-1. Base material As the base material used in the antireflection film substrate of the present invention, any material can be used depending on the use of the antireflection film substrate, etc. Among them, it is preferable to use a transparent substrate made of a general-purpose material. .

Examples of the base material include various shot glasses such as BK7, SF11, LaSFN9, BaK1, and F2, synthetic phased silica glass, optical crown glass, low expansion borosilicate glass, sapphire glass, soda glass, non-alkali glass, and the like. Glass; acrylic resin such as polymethyl methacrylate and crosslinked acrylate; aromatic polycarbonate resin such as bisphenol A polycarbonate; polyester resin such as polyethylene terephthalate; amorphous polyolefin resin such as polycycloolefin; styrene resin such as epoxy resin and polystyrene And polysulfone resins such as polyethersulfone and synthetic resins such as polyetherimide resin. Among these, shot glass, synthetic phased silica glass, optical crown glass, low expansion borosilicate glass, soda glass, alkali-free glass, acrylic resin, aromatic polycarbonate resin, and polysulfone resin are preferable.
In addition, these may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The dimensions of the substrate are arbitrary. However, when a plate-like substrate is used as the base material, the thickness of the substrate is preferably 0.05 mm or more, preferably 0.1 mm or more, and 0.2 mm or more from the viewpoints of mechanical strength and gas barrier properties. Is more preferable. The thickness is preferably 80 mm or less, preferably 50 mm or less, and more preferably 30 mm or less from the viewpoint of weight reduction and light transmittance.

  Further, the surface roughness Ra of the substrate is also arbitrary. However, the surface roughness Ra is preferably 10 nm or less, more preferably 8 nm or less, still more preferably 5 nm or less, and more preferably 3 nm, from the viewpoint of film forming properties, in terms of producing an antireflection film using the composition of the present invention. The following are particularly preferred:

  On the other hand, when imparting antiglare properties and concealing properties, the center line average roughness of the substrate is not limited to the above, and the surface of the substrate preferably has irregularities. Such irregularities may be provided on only one surface or both surfaces of the substrate, but are preferably provided on the surface on which the antireflection film (silica film) is laminated. Specifically, the center line average roughness is usually 0.1 μm or more, preferably 0.2 μm or more, more preferably 0.4 μm or more, and usually 15 μm or less, preferably 10 μm or less. The maximum height Rmax of the surface roughness is usually 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.5 μm or more, particularly preferably 0.8 μm or more, usually 100 μm or less, preferably 80 μm or less. More preferably, it is 50 μm or less, more preferably 30 μm or less, and particularly preferably 10 μm or less.

  By providing an antireflection film (silica film) produced from the above composition on a substrate in the range of the centerline average roughness and the maximum height Rmax of the surface roughness, the film has excellent low reflection characteristics and is prevented. An antireflection film substrate having excellent glare can be provided. When it is below or exceeds the above range, the low reflection effect may be impaired, and the appearance may become opaque. Moreover, the average interval Sm of the irregularities on the surface of the substrate is usually 0.01 mm or more, preferably 0.03 mm or more, and can be usually 30 mm or less, preferably 15 mm or less. The centerline average roughness, the maximum height Rmax of the surface roughness, and the average interval Sm of the irregularities are general-purpose surface roughness meters according to JIS-B0601: 1994 (for example, Surfcom 570A manufactured by Tokyo Seimitsu Co., Ltd.) Measured by

2-2. Method for Forming Thin Film (Silica Film) As a method for forming a thin film to be an antireflection film on the substrate using the composition of the present invention, the composition of the present invention is prepared and then the composition is formed on the substrate. There is no particular limitation on the formation method as long as it is a method in which an object is applied and formed by heat treatment (curing by heating), and other operations may be performed as necessary. For example, aging may be performed during or after the preparation of the composition of the present invention, and a thin film produced using the composition may be heat treated, and the antireflection film substrate may be cooled and post-treated.
In the antireflection film substrate of the present invention, the thickness of the thin film prepared from the above composition is usually 0.05 μm or more, preferably 0.08 μm or more, more preferably 0.01 μm or more, and usually 5 μm. Hereinafter, it is preferably 1 μm or less, more preferably 0.5 μm or less. Thereby, an optical effect can be expressed.

2-2-1. Preparation process In the preparation process of the composition of this invention, each component which comprises this composition is mixed. At this time, there is no limitation on the order of mixing the components. In addition, each component may be mixed all at once, or may be mixed continuously or intermittently in two or more times. However, in order to control the sol-gel reaction which has heretofore been difficult to control and to prepare the composition more industrially, it is preferable to prepare it in the following manner. That is, alkoxysilanes, water, a catalyst and a solvent are mixed, and the mixture is aged to hydrolyze and dehydrate and condense alkoxysilanes to some extent. And the nonionic polymer which concerns on this invention is mixed with the mixture, and this composition is prepared. Thereby, the affinity of alkoxysilanes and a nonionic polymer can be maintained under sol-gel reaction conditions. The aging may be performed after mixing the mixture and the ionic polymer according to the present invention.

  During the ripening, heating is preferably performed in order to advance hydrolysis / dehydration condensation reaction of alkoxysilanes. The heating condition is not particularly limited as long as it does not exceed the boiling point of the solvent to be used, but it is usually 40 ° C. or higher, preferably 50 ° C. or higher, and particularly preferably 60 ° C. or higher. If the heating temperature is too low, the reaction time becomes extremely long, and the productivity may decrease. On the other hand, the upper limit of the heating temperature is preferably 100 ° C. or less, and more preferably 95 ° C. or less. If it exceeds 100 ° C., the water in the composition will boil and the decomposition / dehydration condensation reaction may not be controlled. The aging time is not limited, but is usually 10 minutes or more, preferably 20 minutes or more, more preferably 30 minutes or more, and usually 10 hours or less, preferably 8 hours or less, more preferably 5 hours or less. If the aging time is too short, it may be difficult to proceed with the aging reaction uniformly. If it is too long, the volatilization of the solvent cannot be ignored, the composition ratio may change, and the stability of the liquid may be lowered. Furthermore, although there is no restriction | limiting in the pressure conditions at the time of ripening, Usually, it is preferable to age | cure | ripen by a normal pressure. When the pressure changes, the boiling point of the solvent also changes, and the solvent during aging volatilizes (evaporates), so that the composition ratio changes and the stability of the composition becomes low, and the silica film has excellent humidity resistance stability. May not be obtained.

  Further, it is preferable that the composition of the present invention is further mixed with an organic solvent and diluted after the aging and before the coating step. Thereby, the sol-gel reaction rate in a composition can be reduced, and it becomes possible to maintain the pot life of the composition of this invention long. Further, the diluted composition may be aged for 3 to 5 days or more. Thereby, the unreacted part seen immediately after composition preparation can be reduced, the dispersion | variation in the refractive index at the time of thin film formation can be suppressed, and it can be set as the thin film of the refractive index stable over the long term.

2-2-2. Application Step After the preparation step, an application step of applying (forming a film) the composition is performed. In the coating step, the composition is usually formed on the surface of the substrate. Although there is no restriction | limiting in the method of application | coating, For example, the casting method which extends the composition of this invention on a base material using a bar coater, an applicator, a doctor blade, etc .; a base material is immersed in the composition of this invention, and it pulls up. Well-known examples include a dip coating method; a spin coating method, a capillary coating method, a die coating method, and a spray coating method. Among these methods, a casting method, a die coating method, a spray coating method, and a spin coating method are preferably employed because the composition of the present invention can be uniformly applied. Among them, the spin coating method is particularly preferable for forming a homogeneous film.

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

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

  Further, when the composition of the present invention is formed by spin coating, the rotational speed is usually 10 revolutions / minute or more, preferably 50 revolutions / minute or more, more preferably 100 revolutions / minute or more, and usually 100,000 revolutions. / Min or less, preferably 50000 revolutions / minute or less, more preferably 10,000 revolutions / minute or less. If the rotational speed is too slow, the film thickness may be uneven. If the rotational speed is too fast, the vaporization of the solvent tends to proceed and the reaction such as hydrolysis of alkoxysilanes does not proceed sufficiently and the humidity resistance stability may decrease. is there.

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

  However, in the coating process of the antireflection film substrate of the present invention, the relative humidity is usually 20% or more, preferably 25% or more, more preferably 30% or more, and usually 85% or less, preferably 80% or less, more preferably. Is applied in an environment of 75% or less. By setting the relative humidity in the coating step within the above range, a silica film having high surface smoothness can be obtained. There is no restriction | limiting in the atmosphere in an application | coating process. For example, application may be performed in an air atmosphere, or application may be performed in an inert atmosphere such as argon. Although there is no restriction | limiting in the temperature at the time of performing an application | coating process, Usually, 0 degreeC or more, Preferably it is 10 degreeC or more, More preferably, it is 20 degreeC or more, Usually, 100 degreeC or less, Preferably it is 80 degreeC or less, More preferably, it is 70 degreeC or less. Further, it is preferably 60 ° C. or lower, more preferably 50 ° C. or lower, particularly preferably 40 ° C. or lower. If the temperature at the time of application is too low, the solvent is difficult to evaporate and the surface smoothness of the film may be reduced. If it is too high, curing of the alkoxysilanes proceeds rapidly, and the film distortion may increase. .

  Although there is no restriction | limiting in the pressure at the time of performing an application | coating process, Usually 0.05 Mpa or more, Preferably it is 0.08 Mpa or more, More preferably, it is 0.1 Mpa or more, Usually, 0.3 Mpa or less, Preferably it is 0.2 Mpa or less. Preferably it is 0.15 MPa or less. If the pressure is too low, the solvent tends to evaporate and the leveling effect after coating may not be obtained, and the smoothness of the film may be lowered.If the pressure is too high, the solvent is less likely to evaporate and the surface property of the film may be lowered. There is. Incidentally, there is a difference in drying speed between the dip coating method and the spin coating method, and a slight difference may occur in the stable structure of the film immediately after coating. This can be adjusted by changing the atmosphere during application. In addition, the slight difference in the stable structure of the film can be dealt with by surface treatment of the substrate. Prior to coating the composition of the present invention on the substrate, the substrate is subjected to a surface treatment from the viewpoint of the wettability of the composition of the present invention and the adhesion of the formed antireflection film. May be. Examples of such surface treatment include silane coupling treatment, corona treatment, UV ozone treatment and the like. Moreover, only 1 type may be performed for a surface treatment and you may perform it combining 2 or more types arbitrarily.

  Moreover, although an application | coating process may be performed at once, you may divide into two or more times. For example, an antireflection film having a laminated structure can be formed if the coating process is performed twice or more through a heat treatment process described later. This is useful, for example, when it is desired to stack layers having different refractive indexes.

2-2-3. Heat treatment step After the coating step, a heat treatment step for heat treating the film is performed. By the heat treatment step, the organic solvent and water in the composition of the present invention are dried and removed, the film is cured, and further, the nonionic polymer is removed, whereby an antireflection film (silica film) is formed on the substrate. ) Is formed. By removing the nonionic polymer, a porous silica film is formed, and the composition of the present invention can have the characteristics described above.
The heat treatment method is not particularly limited, but as an example, an in-furnace bake method in which a base material is placed in a heating furnace (baking furnace) and the film of the composition of the present invention is heat-treated, based on a plate (hot plate). A hot plate method in which a silica film prepared from the composition of the present invention is heat-treated through a plate, a heater is disposed on the upper surface side and / or the lower surface side of the substrate, and electromagnetic waves (for example, infrared rays) are emitted from the heater. ) And heat-treating the film prepared from the composition of the present invention.

  There is no restriction | limiting in the heat processing temperature, and it is arbitrary if a silica film can be hardened. Usually 230 ° C. or higher, preferably 300 ° C. or higher, more preferably 320 ° C. or higher, more preferably 350 ° C. or higher, particularly preferably 400 ° C. or higher, and usually 750 ° C. or lower, preferably 500 ° C. or lower, more preferably 450 ° C. It is as follows. If the heat treatment temperature is too low, the refractive index of the resulting silica film may not be lowered or may be colored. On the other hand, if the heat treatment temperature is too high, the adhesion between the substrate and the silica film (antireflection film) may be reduced. In the heat treatment step, the heat treatment may be performed continuously at the heat treatment temperature, but the heat treatment may be performed intermittently.

  When performing the heat treatment, the rate of temperature increase is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1 ° C./min or more, preferably 10 ° C./min or more, and usually 500 ° C./min or less, preferably 300 The temperature is raised at a temperature of ℃ / min or less. If the rate of temperature rise is too slow, the film may become dense, resulting in increased film strain and reduced humidity resistance stability.If the rate of temperature rise is too fast, the film strain will increase and humidity stability will be reduced as well. May be lower. The time for performing the heat treatment is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 30 seconds or more, preferably 1 minute or more, more preferably 2 minutes or more, and usually 5 hours or less, preferably 2 hours or less, More preferably, it is 1 hour or less. If the heat treatment time is too short, there is a possibility that the nonionic polymer cannot be removed sufficiently. If it is too long, the reaction of the alkoxysilane proceeds and the adhesion to the substrate may be lowered.

The pressure during the heat treatment is arbitrary as long as the effects of the present invention are not significantly impaired, but a reduced pressure environment is preferable. This is because the vaporization of the solvent proceeds more than the reaction of alkoxysilane, which may result in a film having low humidity resistance stability. From this viewpoint, in the heat treatment step, the pressure is usually 0.2 MPa or less, preferably 0.15 MPa or less, more preferably 0.1 MPa or less. On the other hand, the lower limit of the pressure is not limited, but is usually 10 ⁻⁴ MPa or more, preferably 10 ⁻³ MPa or more, more preferably 10 ⁻² MPa or more. If the pressure is too low, the vaporization of the solvent proceeds more than the reaction of alkoxysilane, which may result in a film having low humidity resistance stability. The atmosphere during the heat treatment is arbitrary as long as the effects of the present invention are not significantly impaired, but among them, an environment in which drying unevenness is unlikely to occur is preferable. Among these, it is preferable to perform the heat treatment in an air atmosphere. It is also possible to perform an inert gas treatment and dry in an inert atmosphere. As described above, by performing heat treatment, the film produced from the composition of the present invention can be cured to obtain the antireflection film substrate of the present invention.

2-2-4. Cooling Step After the heat treatment step, a cooling step may be performed as necessary. In the cooling step, the antireflection film substrate of the present invention, which has become a high temperature in the heat treatment step, is cooled. At this time, the cooling rate is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1 ° C./min or more, preferably 0.5 ° C./min or more, more preferably 0.8 ° C./min or more, More preferably, it is 1 ° C./min or more, usually 50 ° C./min or less, preferably 30 ° C. or less, more preferably 20 ° C./min or less, still more preferably 10 ° C./min or less. If the cooling rate is too slow, the production cost may increase. If it is too fast, the film quality is expected to deteriorate due to the difference in linear expansion between adjacent films. The atmosphere in the cooling step is arbitrary as long as the effects of the present invention are not significantly impaired, and may be, for example, a vacuum environment or an inert gas environment. Furthermore, although there is no restriction | limiting in temperature and humidity, normally it cools at normal temperature and normal humidity.

2-2-5. Post-treatment step After the heat treatment step, a post-treatment step may be performed as necessary. Although there is no restriction | limiting in the specific operation performed at a post-processing process, For example, the surface can be made more excellent in functionality by processing the obtained anti-reflective film board | substrate with a silylating agent. As a specific example, by treating with a silylating agent, hydrophobicity is imparted to the antireflection film substrate of the present invention, and the pores of the silica film can be prevented from being contaminated by impurities such as alkaline water. .

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

  As a specific operation of silylation, for example, a silylating agent is applied to a silica film (antireflection film) prepared from the composition of the present invention, an antireflection film substrate is immersed in the silylating agent, This can be done by exposing the antireflection film substrate to the vapor of a silylating agent. Further, as another example of the post-treatment, the non-reacted silanol present in the porous structure can be reduced by aging the antireflection film substrate of the present invention under humid conditions. It is also possible to further improve the humidity resistance stability of the antireflection film prepared from the composition.

2-2-6. Others In the antireflection film substrate of the present invention, as long as the effects of the present invention are not significantly impaired, any process may be performed at any stage before, during or after each process described above during manufacturing. Good. In the antireflection film substrate of the present invention, the composition of the present invention was formed into a film shape, but if it is formed into a shape other than the film shape, a forming step of forming into a predetermined shape can be performed instead of the coating step. That's fine.

3. Solar cell system The solar cell system of the present invention comprises the above-mentioned antireflection film substrate on the light receiving surface side, for example, an antireflection film in which an antireflection film is formed on a substrate using the composition of the present invention. The film substrate can be configured to be used for coating on the light receiving surface side that takes in the light energy of the solar cell system.
An example of the solar cell system of the present invention is shown in FIG. In the solar cell system, a pair of electrodes 1 and 3 are usually provided, and the semiconductor layer 2 is positioned between the electrodes 1 and 3. There may also be an intermediate layer 4 between the substrate 5 and the electrode 3. In general, the antireflection film substrate (base material 5 and antireflection film 6) is configured to be on the light receiving surface side.
In the present invention, in addition to the above-described components, a heat ray blocking layer, an ultraviolet deterioration preventing layer, a gas barrier layer, a hydrophilic layer, an antifouling layer, an antifogging layer, a moisture proof layer, an adhesive layer, a hard layer, a conductive layer, a reflective layer A layer, an antiglare layer, a diffusion layer or the like (not shown) may be further combined.

  Here, the solar cell system is an element or device that can convert light energy into electric power by utilizing the photovoltaic effect, and examples thereof include a single crystal silicon solar cell, a polycrystalline silicon solar cell, and an amorphous material. Silicon solar cells such as silicon solar cells, CIS solar cells, CIGS solar cells, compound solar cells such as GaAs solar cells, dye-sensitized solar cells, organic thin film solar cells, multi-junction solar cells, HIT solar Although a battery is mentioned, it does not specifically limit to these.

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

Moreover, the semiconductor layer 2 may be comprised only by the single film | membrane, and may be comprised by the 2 or more film | membrane. Among them, a semiconductor having a wide spectral sensitivity is preferable, and an antireflection effect can be obtained by using a tandem semiconductor layer.
The thickness of the semiconductor layer 2 is not particularly limited, but is usually 5 nm or more, preferably 10 nm or more, and usually 10 μm or less, preferably 5 μm or less.

  On the other hand, the electrodes 1 and 3 can be formed of any conductive material. The electrodes 1 and 3 are for taking out electrical energy generated in the semiconductor layer 2. However, it is preferable that at least one of the pair of electrodes 1 and 3 is transparent (that is, transmits light absorbed by the semiconductor layer 2 to generate power by the solar cell system). Examples of transparent electrode materials include oxides such as ITO and indium zinc oxide (IZO); and metal thin films. In addition, the material of an electrode may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. Furthermore, two or more electrodes may be laminated, and characteristics (electric characteristics, wetting characteristics, etc.) due to surface treatment may be improved. However, the total light transmittance of C light from the antireflection film substrate 5 to the semiconductor layer 2 is preferably 80% or more, more preferably 83% or more, and still more preferably 86% or more. 90% or more is particularly preferable. This is because the higher the light transmittance, the more efficiently the solar cell system can generate power. The total light transmittance is ideally 100%, but it is usually 99% or less in consideration of partial reflection on the surface of the antireflection film produced using the composition of the present invention. Since the antireflection film produced from the composition of the present invention is excellent in humidity stability as well as a low refractive index, it is possible to exhibit performance very suitable for the solar cell system in this way.

4). Other devices The silica film produced from the composition of the present invention is suitable for an electroluminescence (EL) element in that it has a smooth surface.
An electroluminescence element using a silica film produced from the composition of the present invention may be any element as long as it has an electroluminescence layer between the silica film, two electrodes, and the electrode. It is possible to adopt a configuration in which an electrode (cathode), (ii) an electroluminescence layer, (iii) an electrode (anode), (iv) the silica film, and (v) a translucent body are arranged in this order. . As long as the order of (i)-(v) is maintained, you may have another layer between each layer. For example, it is also possible to insert a light scattering layer and / or a high refractive index layer between (iii) the electrode (anode) and (iv) the silica film.

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

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

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

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

  In addition, the electroluminescence element may include, for example, another optical function layer and a protective film. Other optical functional layers can be appropriately selected depending on the application to be used. Moreover, these layers may be provided with only one layer, and may be provided with combining two or more layers arbitrarily.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[Example 1]
(Preparation of composition)
6.78 g of tetraethoxysilane, 6.92 g of methyltriethoxysilane, 2.30 g of ethanol (boiling point 78.3 ° C.), 5.56 g of water, and 13.0 g of 0.3% by weight hydrochloric acid aqueous solution were mixed. The mixture (A) was prepared by stirring in a water bath at 30 ° C. for 30 minutes and further at room temperature for 30 minutes.
Next, 6.14 g of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer (manufactured by ALDRICH (weight average molecular weight 5,800, proportion of ethylene oxide moiety is 30% by weight); hereinafter referred to as “P123” as appropriate) and ethanol 3 The mixture (A) was added to the mixture (B) mixed with 20 g, stirred at room temperature for 60 minutes, and filtered through a 0.45 μm filter (manufactured by Whatman Japan Co., Ltd.). (C) was prepared.
40 ml of this mixture (C) and 36 ml of 1-butanol (boiling point 117.3 ° C.) as a diluent solvent were mixed and stirred at room temperature for 30 minutes to obtain the composition of the present invention.
In this composition, the ratio of silicon atoms derived from tetraethoxysilane, water, and P123 to silicon atoms derived from all alkoxysilanes (tetraethoxysilane and methyltriethoxysilane) was 0.46 and 14.4, respectively. And 0.015 (mol / mol).

[Measurement of water vapor adsorption characteristics]
6.3 ml of the obtained composition was poured into a glass petri dish with a diameter of 120 mm, and the solvent was dried at room temperature and a relative humidity of 40% for 3 days. Thereafter, it was heated and fired at 450 ° C. for 2 hours in an air atmosphere to obtain a powder. The relationship between the relative water vapor pressure at 25 ° C. and the amount of adsorption of the obtained powder was measured using Bell Soap 18 manufactured by Nippon Bell Co., Ltd.
As a result, the water vapor adsorption amount was as shown in FIG. 2, and the water vapor adsorption amount difference Δ at a relative humidity of 0.3 <P / P ₀ <0.9 was 0.005 g / g.

[Measurement of refractive index of film prepared from composition]
Next, the composition of the present invention prepared above was measured with a 1 ml pipettor and applied uniformly on a blue plate glass substrate set on a spin coater (manufactured by Mikasa Co., Ltd.), and spin coated at 500 rpm for 120 seconds. A silica film was produced on a blue plate glass substrate. The obtained silica film substrate was placed on a hot plate set at 450 ° C. and heated in an air atmosphere for 2 minutes to obtain an antireflection film substrate having a good appearance. The refractive index of the obtained antireflection film (silica film) was measured with a spectroscopic ellipsometer and analyzed by a Cauchy model. As a result, the refractive index at a wavelength of 550 nm was 1.18, and the film thickness was 0.69 μm. The results of Example 1 are shown in Table 1.

[Example 2]
The ratio of nonionic polymer to silicon atoms derived from all alkoxysilanes (tetraethoxysilane and methyltriethoxysilane) (nonionic polymer / Si (mol / mol)) is 0.0058 (mol / mol). Except for the above, the same operation as in Example 1 was performed to prepare the composition of the present invention. Thereafter, a powder for measuring the amount of water vapor adsorption was prepared, the amount of water vapor adsorption was measured, and the refractive index of the silica film was further measured. The results are shown in Table 1. Moreover, the result of the water vapor adsorption amount measurement is shown in FIG.

[Comparative Example 1]
(Preparation of composition)
3.47 g of tetraethoxysilane, 2.27 g of methyltrimethoxysilane, 4.60 g of ethanol (boiling point 78.3 ° C.), 0.60 g of water, and 6.1 × 10 ⁻⁵ g of hydrochloric acid were mixed. The mixture (A) was prepared by stirring for 90 minutes in a water bath.
Next, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer (PLURONIC F127 (weight-average molecular weight 12,600, proportion of ethylene oxide moiety 70% by weight) manufactured by BASF; hereinafter referred to as “F127” as appropriate) 2.52 g Ethanol (26.07 g) was mixed and dissolved, and the mixture (A) was added to a mixture (B) in which 2.4 g of water and 0.0048 g of hydrochloric acid were mixed, and the mixture was stirred at room temperature for 3 days. The composition was obtained by filtering with a 45 μm filter (manufactured by Whatman Japan Ltd.).
In the composition, the ratio of silicon atoms derived from tetraethoxysilane, water, and F127 to silicon atoms derived from all alkoxysilanes (tetraethoxysilane and methyltrimethoxysilane) was 0.50, 5.0, respectively. And 0.006 (mol / mol).

[Measurement of water vapor adsorption characteristics]
6.3 ml of the obtained composition was poured into a glass petri dish with a diameter of 120 mm, and the solvent was dried at room temperature and a relative humidity of 40% for 3 days. Then, it heat-baked in the air atmosphere at 400 degreeC for 5 hours, and obtained the powder. The relationship between the relative water vapor pressure at 25 ° C. and the amount of adsorption of the obtained powder was measured using Bell Soap 18 manufactured by Nippon Bell Co., Ltd.

[Measurement of refractive index of film prepared from composition]
Next, the composition prepared above was measured with a 1 ml pipetter, applied uniformly on a blue plate glass substrate set on a spin coater (manufactured by Mikasa Co., Ltd.), spin-coated at 1000 rpm for 60 seconds, and a blue plate glass substrate A silica-containing coating film was prepared thereon. The obtained coating film substrate is placed on a hot plate set at 130 ° C., heated in the air atmosphere for 10 minutes, and then heated at a set temperature of 400 ° C. for 1 hour to obtain an antireflection film substrate having a good appearance. Obtained. The refractive index of the obtained antireflection film was measured with a spectroscopic ellipsometer and analyzed with a Cauchy model. The results are shown in Table 1. Moreover, the result of the water vapor adsorption amount measurement is shown in FIG.
In Table 1, the numerical value in the column of nonionic polymer / Si represents the ratio (mol / mol) of nonionic polymer to silicon atoms derived from all alkoxysilanes. The results are shown in Table 1. The measurement result of the water vapor adsorption amount is shown in FIG.

上記表１において、耐湿度安定性の評価は、下記の手法により行なった。

In Table 1 above, the humidity resistance stability was evaluated by the following method.

[Evaluation of humidity resistance stability]
A silica film made from the composition was stored for 100 hours in an environment of 85 ° C. and 85% relative humidity, and the change in the refractive index was measured. The change was 0.05 or less and there was no change in appearance. Was marked as “◯”. The refractive index was measured with a spectroscopic ellipsometer and analyzed with a Cauchy model. The results are shown in Table 1. In Comparative Example 1, cracks occurred in the film.

〔result〕
From Table 1, in Example 1 and Example 2 in which the water vapor adsorption amount difference Δ at relative humidity 0.3 <P / P ₀ <0.9 is 0.03 g / g or less, the humidity resistance stability is good. there were. On the other hand, in Comparative Example 1 where the water vapor adsorption amount difference Δ is greater than 0.03, the humidity resistance stability was low.
In Comparative Example 1, since the H ₂ O / Si in the composition was small and the amount of water was small, unreacted alkoxy groups remained in the film, which became hydrophilic sites by the heat treatment process, It is presumed that the difference in adsorption amount becomes large, and as a result, the stability against humidity is low.

  The present invention can be used in any industrial field, and can be used, for example, in any optical application. Among them, according to the present invention, it is possible to improve the humidity resistance stability as compared with the prior art, and therefore, it is suitable for use for outdoor use such as solar cells.

It is a schematic sectional drawing which shows an example of the solar cell system of this invention. It is a graph which shows the water vapor adsorption amount measurement result of the Example and comparative example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 3 Electrode 2 Semiconductor layer 4 Intermediate layer 5 Transparent substrate 6 Porous body

Claims (12)

At least one selected from the group of tetraalkoxysilanes consisting of tetraalkoxysilanes, hydrolysates and partial condensates thereof, and other alkoxys consisting of alkoxysilanes other than tetraalkoxysilanes, hydrolysates and partial condensates thereof At least one combination selected from the silane group, and / or at least one partial condensate selected from the tetraalkoxysilane group and at least one partial condensate selected from the other alkoxysilane groups, water, an organic solvent, and ethylene A composition containing a silicon compound, comprising a nonionic polymer having an oxide moiety, wherein the ratio of water to silicon atoms derived from all alkoxysilanes is 10 (mol / mol) or more,
The refractive index of the film obtained by applying the composition to a substrate and baking it at 400 ° C. or higher and 450 ° C. or lower for 1 minute or longer and 1 hour or shorter is 1.25 or lower,
The composition was air-dried at room temperature under a relative humidity of 40% for 3 days, and then calcined at 400 ° C to 450 ° C for 1 minute to 5 hours at 25 ° C. The water vapor adsorption amount difference Δ at a relative water vapor pressure of 0.3 <P / P ₀ <0.9 is 0.03 g / g or less.
(Here, P is the water vapor partial pressure at 25 ° C., and P ₀ is the saturated water vapor pressure at 25 ° C.) The composition of claim 1, characterized by further comprising a catalytic. The composition according to claim 2, wherein the nonionic polymer having an ethylene oxide moiety has a weight average molecular weight of 4,300 or more. The ratio of silicon atoms derived from tetraalkoxysilanes to silicon atoms derived from all alkoxysilanes is 0.3 (mol / mol) or more and 0.7 (mol / mol) or less. 4. The composition according to any one of 3. The composition according to any one of claims 1 to 4, wherein 80% by weight or more of the organic solvent is an organic solvent having a boiling point of 55 ° C or higher and 140 ° C or lower. The ratio of the nonionic polymer having the ethylene oxide moiety to the silicon atoms derived from all alkoxysilanes is 0.001 (mol / mol) or more and 0.05 (mol / mol) or less, The composition as described in any one of Claims 2-5. The composition according to any one of claims 2 to 6, wherein the content of the ethylene oxide moiety in the nonionic polymer having the ethylene oxide moiety is 20% by weight or more. The nonionic polymer having an ethylene oxide moiety is at least one nonionic polymer selected from the group consisting of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer and polyethylene glycol, The composition according to any one of claims 2 to 7. The tetraalkoxysilane is tetraethoxysilane;
The alkoxysilane other than the tetraalkoxysilane is a monoalkylalkoxysilane or dialkylalkoxysilane having an aromatic hydrocarbon group or an aliphatic hydrocarbon group. A composition according to 1. The organic solvent contains at least one selected from the group consisting of ethanol, 1-propanol, t-butanol, 2-propanol, 1-butanol, 1-pentanol and ethyl acetate. 10. The composition according to any one of items 9. An antireflection film substrate comprising a thin film obtained by heat-treating the composition according to any one of claims 1 to 10 on a base material. A solar cell system comprising the antireflection film substrate according to claim 11 on the light receiving surface side.

Images