JP2012242666A - Composition for forming coating, substrate with antireflective coating, and solar cell module with antireflective coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for forming antireflective coatings having a low refractive index, capable of evenly forming a coating to a substrate, and capable of forming the coating with antifouling property by surface hydrophilization and high film strength.SOLUTION: The composition for forming a coating includes titanium oxide, silicon oxide, and organic silicon-based surfactant. A molar concentration of Si to a molar concentration of Ti is 5 to 20, a surface tension of the composition for forming the coating is 20 mN/m to 35 mN/m, a mean diffusion constant of the composition for forming the coating at 25°C is 6.5×10cm/s to 8.0×10cm/s, and an electrophoretic mobility of the composition for forming the coating is -5.0×10cm/V s to -4.0×10cm/V s.

Description

  The present invention relates to a film-forming composition for forming an antireflection film used in various displays such as photoelectric conversion elements, CRTs, LCDs, PDPs, touch panels, camera lenses, and photolithography, and an antireflection film using the same. The present invention relates to a substrate and a solar cell module with an antireflection coating.

  The antireflection film is applied to various optical devices as means for suppressing surface reflection. In particular, in the field of solar cells, there have been various attempts to apply antireflection processing to the light incident surface of the solar cell in order to improve output. Among them, the sol-gel method is a method for forming an antireflection film having low production cost and excellent production compatibility. For example, Patent Document 1 discloses that a titania-silica film is formed on a substrate by a sol-gel method to develop an antireflection function. Using the amorphous titanium peroxide and silicon alkoxide as starting materials, a film-forming composition containing a metal-containing anatase-type titanium oxide, a silicon compound, and a thermally decomposable compound is prepared. A low-reflective substrate is produced using this.

JP 2009-212435 A

  As described above, a composition for forming a film mainly containing titania-silica as a main component has been known using amorphous titanium peroxide and silicon alkoxide as starting materials. However, in order to apply to an antireflection film of a solar cell (photoelectric conversion element) exposed to the outdoors over a long period of time, a film having a low refractive index and a long-term adhesion of the film to the substrate are required. It is done. In fact, when the inventors evaluated these known film properties, a film produced from a conventionally known film-forming composition was not sufficient to satisfy these requirements. First of all, even when a film is excellent in antireflection performance, unevenness is often observed when a film is formed on a substrate. Next, titanium peroxide (peroxotitanic acid), which is one of the film-forming composition components described in the above-mentioned documents, is an unstable substance. Therefore, it is obtained depending on the preparation conditions and storage conditions after preparation, for example, temperature. The physical properties of the resulting coating are greatly different.

  In view of the circumstances, the present invention provides a film-forming composition that is excellent in durability of a film, is easy to form a film without unevenness, and can form a low refractive index film having high antireflection performance. Objective. Furthermore, the composition for forming a film according to the present invention also provides an antifouling effect by making the surface hydrophilic.

  Another embodiment of the present invention provides a substrate on which a low refractive index film having excellent durability, no unevenness, and high antireflection performance is formed. Furthermore, a solar cell with improved photoelectric conversion performance is provided by forming a low refractive index film having excellent durability, no unevenness, and high antireflection performance on the light incident surface.

  The inventor diligently studied the composition of the film-forming composition using titanium oxide as the titania element, the partial hydrolyzate of the alkyl silicate as the silica element, and the organosilicon surfactant, and the change over time in the liquid properties, and applied the present invention. It came.

The first of the present invention is a film-forming composition comprising titanium oxide, silicon oxide, and organosilicon surfactant, wherein the molar concentration of Si / the molar concentration of Ti is 5 to 20. The autocorrelation function measured by the dynamic scattering device at a scattering angle of 90 degrees and a temperature of 25 degrees is calculated by analyzing the autocorrelation function by a cumulant method with a surface tension to air by the dropping method of 20 mN / m to 35 mN / m. that the average diffusion constant for the diffusion constant is determined by an arithmetic average is ^{6.5 × 10 -8 cm 2 /s~8.0×10 -8} cm 2 / s, electrophoresis a laser on a dynamic scattering device The electrophoretic mobility measured at 25 ° C. by the Doppler method is −5.0 × 10 ⁻⁴ cm ² / V · s to −4.0 × 10 ⁻⁴ cm ² / V · s, for film formation. A composition.

  A second aspect of the present invention is the film forming composition, wherein the titanium oxide is an amorphous type.

  Since the titanium oxide is an amorphous type, there is an advantage that a film with higher adhesion is formed compared to a crystalline type (anatase type, rutile type), which is preferable.

  3rd of this invention is the said composition for film formation whose said titanium oxide is a titanium peroxide.

  When the titanium oxide is titanium peroxide, the peroxo group of titanium peroxide forms a chemical bond with the substrate surface when the film is formed, and a film with higher adhesion can be obtained.

  The fourth aspect of the present invention is the above-described film-forming composition, further doped with one or more elements selected from the group consisting of copper, zirconium, tin, zinc, antimony and silver. The addition of these elements is preferable because it has the effect and advantage of exhibiting antifouling, antibacterial and antistatic functions.

  5th of this invention is a board | substrate with an antireflection film obtained by apply | coating the said composition for film formation to a board | substrate, and heating. There is an effect and advantage that a stronger film can be formed by heating, which is preferable.

  6th of this invention is a solar cell module with an antireflection film obtained by apply | coating the said composition for film formation to a solar cell module, and heating.

7th of this invention is a manufacturing method of the board | substrate with an antireflection film including the process of apply | coating to a board | substrate the composition for film formation containing a titanium oxide, a silicon oxide, and an organosilicon surfactant. The molar concentration of Si / Molar concentration of Ti is 5 to 20, the surface tension against air by the dropping method is 20 mN / m to 35 mN / m, and measured by a dynamic scattering apparatus at a scattering angle of 90 degrees and a temperature of 25 degrees. The average diffusion constant obtained by arithmetically averaging the diffusion constants calculated by analyzing the autocorrelation function obtained by the cumulant method is 6.5 × 10 ⁻⁸ cm ^{2 / s to} 8.0 × 10 ⁻⁸ cm. ² / s, and the electrophoretic mobility is −5.0 × 10 ⁻⁴ cm ² / V · s to −4.0 × 10 ⁻⁴ cm ² / V · s. And confirming the film forming composition A step of applying to the plate, and a step of heating, a method of manufacturing anti-reflection film-attached substrate is.

  The eighth of the present invention is the method for producing a substrate with an antireflection film, wherein the substrate is a glass substrate or a solar cell module in which a solar cell element is laminated on a glass substrate. .

  By using the film forming composition according to the present invention, it is possible to form an antireflection film having high performance in terms of antireflection function and film strength without unevenness on the light incident surface of a solar battery cell or the like. Furthermore, since the surface becomes hydrophilic, dirt on the surface is efficiently washed away by rain or the like. Combined with these effects, for example, when an antireflection film is formed on the light incident surface of the solar battery cell with the film-forming composition according to the present invention, high light transmittance is maintained over a long period of time, The battery cell can obtain high power generation efficiency.

  The film-forming composition of the present invention contains at least a titanium oxide, a silicon oxide, and an organosilicon surfactant.

  Titanium oxide includes what is called titanium dioxide, titanium peroxide, titanium hydroxide, metatitanic acid, and orthotitanic acid. Among these, titanium peroxide is particularly preferable. This is because the peroxo group of titanium peroxide forms a chemical bond with the substrate surface at the time of film formation, and a stronger film strength can be obtained.

Commercially available aqueous solutions of titanium peroxide include (1) Amorphous titanium peroxide aqueous solution (SP) manufactured by Sustainable Technology Co., Ltd. (2) Photooxidized positively charged metal oxide doped amorphous titanium peroxide aqueous solution (SPZ high function) Type), (3) Amorphous modified titanium peroxide + carbohydrate complex aqueous solution (DaSH), (4) Asuka Riken Co., Ltd. (4) Fluorescence, (5) ) Tsuruclean (registered trademark) grade A-TS-1, (6) Tsuruclean (registered trademark) grade A-TS-2, and (7) PTA aqueous solution manufactured by Sakai Corporation.
There are the following methods for producing titanium peroxide.

(Manufacturing method 1)
A basic aqueous solution is added to the soluble inorganic titanium compound aqueous solution. When the resulting pale bluish white, amorphous ortho-titanium is washed and separated and then treated with an oxidizing agent, the amorphous titanium peroxide liquid of the present invention is obtained.

Soluble inorganic titanium compounds include titanium chelate, acetate titanium, titanium sulfate,
Examples thereof include titanium tetrachloride. Examples of the basic aqueous solution include sodium hydroxide, potassium hydroxide, ammonia, tetraalkylammonium hydroxide and the like. The reaction of adding a basic aqueous solution to a soluble inorganic titanium compound aqueous solution is a neutralization reaction and involves a large exotherm. This is because when the reaction proceeds at a high temperature, the reaction from orthotitanic acid to metatitanic acid proceeds.

  Any oxidizing agent may be used as long as it can oxidize titanium dioxide to titanium peroxide, but hydrogen peroxide is particularly preferable. When hydrogen peroxide water is used as the oxidizing agent, the concentration of hydrogen peroxide is preferably 30 to 40% because the reaction is accelerated. It is preferred to cool the titanium hydroxide before peroxolation. This is because the peroxoation reaction is an exothermic reaction and the reaction needs to proceed mildly. The cooling temperature at that time is preferably 1 to 5 ° C.

(Manufacturing method 2)
An appropriate amount of titanium alkoxide, alcohol, water and catalyst is mixed to conduct hydrolysis and polycondensation reaction. Furthermore, an amorphous type titanium peroxide liquid can be obtained by adding an oxidizing agent.

  Examples of the titanium alkoxide include tetraethoxy titanium, tetramethoxy titanium, tetrapropoxy titanium, and tetrabutoxy titanium. Examples of the alcohol include methanol, ethanol, n-propanol, and isopropanol. Any oxidizing agent may be used as long as it can oxidize titanium dioxide to titanium peroxide, but hydrogen peroxide is particularly preferable. When hydrogen peroxide water is used as the oxidizing agent, the concentration of hydrogen peroxide is preferably 30 to 40% because the reaction is accelerated. It is preferred to cool the titanium hydroxide before peroxolation. This is because the peroxoation reaction is an exothermic reaction and the reaction needs to proceed mildly. The cooling temperature at that time is preferably 1 to 5 ° C.

  As the shape of titanium oxide, titanium oxide commercially available in the form of particles, powder, or sol can be used. As a crystal system of titanium oxide, there are anatase type, rutile type, and amorphous type (amorphous type), and any of them can be used. Among these, an amorphous type is preferable. This is because a film having higher adhesion is formed as compared with the anatase type and the rutile type.

  The molar concentration of Ti can be changed from time to time depending on the desired antireflection properties and durability. 0.0001 to 0.01 mol / L is preferable, and 0.002 to 0.008 mol / L is more preferable. This is because when the amount of Ti is small, the surface hydrophilizing effect is not achieved. This is because when the amount of Ti is large, the refractive index of the film becomes high and the function as an antireflection film is not achieved.

Silicon oxide has the general formula _{SiR n (OR ') 4-} n (R' and R is an alkyl group having 1 to 5 carbon atoms, n represents a natural number of 0 to 3) a hydrolyzate of silicon alkoxide represented by and / Or a partial hydrolyzate. Furthermore, it is also possible to use a liquid that has been subjected to a condensation polymerization reaction using an acid catalyst or a base catalyst. Further, silica fine particles may be partially added. This is because the addition of silica fine particles increases the film strength.

  The molar concentration of Si can be changed from time to time depending on the desired antireflection properties and durability. 0.001-0.1 mol / L is preferable and 0.02-0.05 mol / L is further more preferable. This is because when the amount of Si is small, the amount of Ti is relatively large, so that the refractive index of the film becomes high and the function as an antireflection film is not achieved. Further, when the amount of Si is large, the amount of Ti is relatively small, so that the surface hydrophilizing effect is not achieved. Moreover, it is also because it becomes difficult to form a film without unevenness because the solution becomes high in concentration and handling at the time of film formation becomes difficult.

  The value of the molar concentration of Si / the molar concentration of Ti is preferably 1 to 30, and more preferably 5 to 20. If the Si molar concentration / Ti molar concentration value is too large, the surface hydrophilization effect by titanium oxide is not sufficient, and if it is too small, the refractive index of the film increases and the function as an antireflection film is not achieved. is there.

  As the organosilicon surfactant, commercially available various silicone surfactants can be used as appropriate. Specifically, TSF4445, TSF4446 (GE Toshiba Silicone Co., Ltd.), KP series (Shin-Etsu Chemical Co., Ltd.), SH200, SH3746, DC3PA, ST869A (Toray Dow Corning Co., Ltd.) are used. Can do. As the silicone, those having an alkyl silicate structure or a polyether structure in the molecule, or those having both an alkyl silicate structure and a polyether structure are preferable. Here, the alkyl silicate structure refers to a structure in which an alkyl group is bonded to a silicon atom of a siloxane skeleton. On the other hand, the polyether structure means a structure having an ether bond, such as polyethylene oxide, polypropylene oxide, polytetramethylene oxide, polyethylene oxide-polypropylene oxide block copolymer, polyethylene polytetramethylene glycol copolymer, polytetramethylene. Examples thereof include a molecular structure such as a glycol-polypropylene oxide copolymer. Among these, a polyethylene oxide-polypropylene oxide block copolymer is preferable from the viewpoint of controlling the surface tension. As the organosilicon compound, silicone having both alkyl silicate structure and polyether structure in the molecule is particularly preferable. Specifically, polyether-modified silicone such as polyether-modified polydimethylsiloxane is suitable.

  The film forming composition of the present invention has a solid content concentration of more preferably 1% or less, and most preferably 0.5% or less. This is because if the concentration is too high, the stability of the liquid is poor.

  More preferably, the film-forming composition of the present invention is further doped with one or more elements selected from copper, zirconium, tin, zinc, antimony and silver. This is because the addition of these metals exhibits antifouling, antibacterial and antistatic functions.

  The method for doping these metals can be achieved by adding a metal oxide or a metal salt during the synthesis of the above titanium oxide and silicon oxide. Examples of commercially available metal-doped titanium oxides include photooxidized positively charged metal oxide-doped amorphous titanium peroxide aqueous solution (SPZ high-functional type, Sustainable Technology Co., Ltd.).

  Examples of the metal oxide or metal salt include the following. Copper: Copper hydroxide, copper chloride, copper sulfate, copper nitrate, copper acetate, copper oxide. Zirconium: Zirconium hydroxide, zirconium dichloride, zirconium tetrachloride, zirconium sulfate, zirconium nitrate, zirconium acetate, zirconium oxide. Tin: Tin hydroxide, tin chloride, tin sulfate, tin nitrate, tin acetate, tin oxide. Zinc: Zinc hydroxide, zinc chloride, lead sulfate, zinc nitrate, zinc acetate, zinc oxide. Antimony: antimony hydroxide, antimony chloride, antimony sulfate, antimony nitrate, antimony acetate, antimony oxide. Silver: Silver hydroxide, silver chloride, silver sulfate, silver nitrate, silver acetate, silver oxide.

  Metal doping can be performed in a timely manner in the production process of the film forming solution, but is preferably performed during the synthesis of titanium oxide. This is because removal of by-products can be easily performed by washing with water.

The following is mentioned as an example of the specific manufacturing method which doped the metal.
One or more of copper chloride, zirconium chloride, zinc chloride, tin chloride, antimony chloride, and silver chloride is added to the titanium tetrachloride compound aqueous solution. A basic aqueous solution such as an aqueous ammonia solution is added to this solution. When the resulting pale bluish white, amorphous titanium hydroxide is washed and separated and then treated with hydrogen peroxide, the metal-doped amorphous titanium peroxide liquid of the present invention is obtained. When ammonia is used in a basic aqueous solution, the by-product is ammonium chloride, which is water-soluble. Therefore, since ammonium chloride is dissolved in the step of washing titanium hydroxide, metal-doped amorphous titanium peroxide with few impurities can be obtained.

  The solvent for the film-forming composition according to the present invention is not particularly limited as long as it has the ability to disperse solute components, but it is desirable from the viewpoint of safety to use alcohol, water or a mixture thereof. Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, isobutanol and the like.

  The surface tension of the film-forming composition according to the present invention is 20 mN / m to 35 mN / m, more preferably 30 mN / m to 35 mN / m. This is because when the surface tension is larger than these ranges, the wettability with respect to the substrate is deteriorated and unevenness occurs when a film is formed. In particular, the film-forming composition according to the present invention exhibits good wettability with respect to a glass substrate and forms a film with little unevenness. Although the reason is unknown, it is considered that the specific intermolecular interaction between the glass component silicon dioxide and the titania-silica component of the film-forming composition according to the present invention contributes to the improvement of wettability.

The numerical range of the surface tension of the film forming composition according to the present invention was determined by the following examination.
In general, in order to form a film uniformly on a substrate, it is required that the wettability of the film-forming solution with respect to the substrate is high. On the other hand, the inventors have found that the organosilicon surfactant has an effect of lowering the surface tension, but when the organosilicon surfactant concentration is high, the film strength is remarkably lowered. Furthermore, it was found that the surface tension strongly depends on the concentration of the organosilicon surfactant and the degree of deactivation of the organosilicon surfactant. That is, (1) The surface tension decreases as the concentration of the organosilicon surfactant increases, and saturates at a certain concentration or more. (2) The surface tension takes several days to a month after mixing the organosilicon surfactant. (3) The surface tension increases at a slower rate as the concentration of the organosilicon surfactant decreases. The inventors diligently studied the balance between the wettability with respect to the substrate and the film strength, and reached the above numerical range.

Further, the surface tension of the film-forming composition depends on the amount of the organosilicon surfactant and the time after preparation. That is, assuming that the amount of the organosilicon surfactant in the film forming liquid is X%, and the period after preparation of the film forming liquid is Y days, Y ≧ 2, X ≧ 0.5, Y ≧ −3X + 15, Y ≦ −. In the range represented by the four inequalities of X + 18, the surface tension is 20 mN / m to 35 mN / m, and the average diffusion constant at 25 degrees is 6.5 × 10 ⁻⁸ cm ^{2 / s to} 8.0 × 10. ⁻⁸ cm ² / s and the electrophoretic mobility is within the range of −5.0 × 10 ⁻⁴ cm ² / V · s to −4.0 × 10 ⁻⁴ cm ² / V · s. . That is, by controlling to the range shown by the above inequality, the surface tension is 20 mN / m to 35 mN / m, and the average diffusion constant at 25 degrees is 6.5 × 10 ⁻⁸ cm ² / s. To 8.0 × 10 ⁻⁸ cm ² / s and the electrophoretic mobility is −5.0 × 10 ⁻⁴ cm ² / V · s to −4.0 × 10 ⁻⁴ cm ² / V ·. s film-forming composition can be made.

  In addition, the surface tension based on this invention was measured 10 times using the contact angle meter (PCA-1 (made by Kyowa Interface Science)), and the arithmetic mean value was used. The temperature at that time is 25 degrees ± 1 degree.

Average diffusion constant at 25 degrees according coating composition of the present invention is ^{6.5 × 10 -8 cm 2 /s~8.0×10 -8} cm 2 / s. This is because when the diffusion constant is larger than this range, the polymerization of the constituent silica component does not proceed sufficiently, and when a film is formed, a film having a high refractive index can be formed. Moreover, when the diffusion constant is smaller than this range, the polymerization of the silica component is extremely advanced, and a film having low strength can be formed. Moreover, it is because the viscosity of the composition for film formation is high and a restriction | limiting is added to a film formation process.

  A dynamic light scattering device (SZ-100 (manufactured by Horiba)) was used for the measurement of the diffusion constant according to the present invention. The measurement was carried out at 25 degrees. The measurement was performed using a 1 cm quartz cell, and the scattering angle was 90 degrees. The autocorrelation function obtained by the measurement was analyzed by the cumulant method, and the diffusion constant was calculated. The measurement was repeated three times in succession, and the arithmetic average was taken as the average diffusion constant.

The electrophoretic mobility of the film-forming composition according to the present invention is −5.0 × 10 ⁻⁴ cm ² / V · s to −4.0 × 10 ⁻⁴ cm ² / V · s. This is because, when the electrophoretic mobility is larger than this range, the charged state of the fine particles of titanium oxide and silicon oxide is insufficient and the dispersion stability is poor. Moreover, when it is smaller than these values, the organosilicon surfactant is deactivated, and the wettability with respect to the substrate is deteriorated.

  The substrate used for the second embodiment of the present invention, that is, the substrate with an antireflection coating, is not particularly limited as long as it can form a coating using the coating forming composition. In particular, a substrate used in a photoelectric conversion element typified by a solar cell is required to have translucency, and for example, glass, a transparent polymer film, or the like is used. Examples of the method for applying the film forming composition to the substrate include a spray method, a dip coating method, a spin coating method, and a squeegee coating method.

  The lower limit of the temperature at which the substrate is heated is preferably 40 degrees or more, more preferably 60 degrees or more, and most preferably 80 degrees or more. This is because a stronger film can be formed at higher temperatures. Moreover, as an upper limit of the temperature which heats a board | substrate, 250 degrees or less is preferable, 200 degrees or less is more preferable, and 180 degrees or less is the most preferable. This is because, when the temperature is raised, the substrate itself undergoes a thermal change, causing adverse effects such as discoloration. The heating time is preferably 5 minutes or longer, more preferably 10 minutes or longer, and most preferably 15 minutes or longer. This is because a stronger film can be formed as the heating time is longer.

  The solar cell module used in the third embodiment of the present invention, that is, the solar cell module with an antireflection coating, is not particularly limited as long as it is a solar cell module capable of forming a coating using the coating forming composition. However, a solar cell module in which a photoelectric conversion element is formed on glass, a transparent polymer film or the like is optimally used. Examples of the method for applying the film forming composition to the solar cell module include a spray method, a dip coating method, a spin coating method, and a squeegee coating method. The lower limit of the temperature at which the solar cell module is heated is preferably 40 degrees or more, more preferably 60 degrees or more, and most preferably 80 degrees or more. This is because a stronger film can be formed at higher temperatures. Moreover, as an upper limit of the temperature which heats a board | substrate, 250 degrees or less is preferable, 200 degrees or less is more preferable, and 180 degrees or less is the most preferable. This is because, when the temperature is raised, the substrate itself undergoes a thermal change, causing adverse effects such as discoloration. Moreover, it is because the cell part of a solar cell receives a thermal damage when it makes it high temperature. The heating time is preferably 5 minutes or longer, more preferably 10 minutes or longer, and most preferably 15 minutes or longer. This is because a stronger film can be formed as the heating time is longer.

(Evaluation liquid 1)
Partial hydrolyzate of silica sol liquid (partial condensate of tetraethyl silicate, Si _n O _n-1 (OC ₂ H ₅ ) _{2 (n + 1),} n = 4 to 6; (Tama Chemical Industry Co., Ltd.)), Copper-doped titania aqueous dispersion: Z18-1000 Super A (Sustainable Technology Co., Ltd.) is mixed, diluted with pure water, and the molar concentrations of Si and Ti in the solution are 0.025 mol / L and 0.0025 mol, respectively. did. To this mixture, 10 wt% of organosilicon surfactant: Z-B (Sustainable Technology Co., Ltd.) was added to obtain Evaluation Solution 1. It was 0.45 wt% when the solid content density | concentration of the evaluation liquid 1 was measured using the infrared moisture meter.

(Evaluation liquid 2)
A film forming solution (referred to as Evaluation Solution 2) was prepared in the same manner as Evaluation Solution 1 except that the amount of addition of organosilicon surfactant: Z-B (Sustainable Technology Co., Ltd.) was 3 wt%.

(Evaluation liquid 3)
A film-forming solution (referred to as Evaluation Solution 3) was prepared in the same manner as Evaluation Solution 1 except that the addition amount of organosilicon surfactant: Z-B (Sustainable Technology Co., Ltd.) was 20 wt%.

Example 1
The evaluation liquid 1 was maintained at 25 ° C. for 48 hours after preparation, and the diffusion constant of particles in the evaluation liquid was measured by a cumulant method using a dynamic light scattering apparatus (SZ-100 (manufactured by Horiba)). × 10 ⁻⁸ cm ² / s. Moreover, it was -4.2 * 10 < ^-4 > cm < ² > / V * s when the electrophoretic mobility was measured by the electrophoresis laser Doppler method using the same apparatus. Next, when the surface tension of the liquid was measured using a contact angle meter (PCA-1 (manufactured by Kyowa Interface Science)), it was 32 mN / m.
Moreover, it applied with the spray method so that it might become a coating amount of 48 g / m2 with respect to the white glass (10 cm x 10 cm) which surface-cleaned the liquid hold | maintained at 25 degree | times for 48 hours after producing the evaluation liquid 1. After the application, oven drying was performed at 90 ° C. for 15 minutes. A coating was formed on the white plate glass.

The coated white plate glass was completely coated with a uniform coating. Moreover, when the film thickness of the film and the refractive index at a wavelength of 600 nm were measured using spectroscopic ellipsometry, they were 110 nm and 1.43, respectively. Moreover, when the average transmittance | permeability of the board | substrate in 400 nm-700 nm was measured, 3% transmittance | permeability was high compared with the film formation front.
Here, the average transmittance was measured using a spectrophotometer (UV-3100 manufactured by Shimadzu Corporation). Further, no unevenness was observed in appearance.

(Comparative Example 1)
Analysis evaluation (diffusion constant, electrophoretic mobility, surface tension) of the solution was performed in the same manner as in Example 1 using the solution within 1 hour after producing the evaluation solution 1. The diffusion constant, electrophoretic mobility, and surface tension were 7.5 × 10 ⁻⁸ cm ² / s, −3.8 × 10 ⁻⁴ cm ² / V · s, and 31 mN / m, respectively.

  In addition, a coating film was produced in the same manner as in Example 1 using a liquid within 1 hour after producing the evaluation liquid 1. The film thickness and refractive index were 100 nm and 1.49, respectively. Moreover, when the average transmittance | permeability of the board | substrate in 400 nm-700 nm was measured, the transmittance | permeability rose only 1% compared with before film formation. Compared with Example 1, it is considered that the antireflection effect was not sufficiently exhibited due to the film having a higher refractive index, and the increase in transmittance was small.

(Comparative Example 2)
Analysis evaluation (diffusion constant, electrophoretic mobility, surface tension) of the liquid was performed in the same manner as in Example 1, using the liquid that was held at 25 degrees for 14 days after the evaluation liquid 1 was prepared. The diffusion constant, electrophoretic mobility, and surface tension were 5.5 × 10 ⁻⁸ cm ² / s, −4.3 × 10 ⁻⁴ cm ² / V · s, and 39 mN / m, respectively.

  In addition, a coating film was prepared in the same manner as in Example 1 using a liquid that was maintained at 25 degrees for 14 days after the evaluation liquid 1 was prepared. When applied by spraying, the wettability with respect to the white glass was poor and unevenness was observed. Further, when an oven-dried film was observed, a uniform film was not formed at the end.

  The portion where the film was sufficiently formed was measured by spectroscopic ellipsometry. The film thickness and refractive index were 110 nm and 1.39, respectively. Moreover, when the average transmittance | permeability of the board | substrate in 400 nm-700 nm was measured, the 2.8% transmittance | permeability was high compared with the film formation front.

(Example 2)
Analysis evaluation (diffusion constant, electrophoretic mobility, surface tension) of the liquid was performed in the same manner as in Example 1 using the liquid that was held at 25 degrees for 7 days after the evaluation liquid 2 was prepared. The diffusion constant, electrophoretic mobility, and surface tension were 6.9 × 10 ⁻⁸ cm ² / s, −4.8 × 10 ⁻⁴ cm ² / V · s, and 32 mN / m, respectively.

  In addition, a film was prepared in the same manner as in Example 1 using a liquid that was held at 25 degrees for 7 days after the evaluation liquid 2 was prepared. The film thickness and refractive index were 110 nm and 1.42, respectively. Moreover, when the average transmittance | permeability of the board | substrate in 400 nm-700 nm was measured, 3% transmittance | permeability was high compared with the film formation front. Further, no unevenness was observed in appearance.

(Comparative Example 3)
Analysis evaluation (diffusion constant, electrophoretic mobility, surface tension) of the liquid was performed in the same manner as in Example 1 using the liquid maintained at 25 degrees for 30 days after the evaluation liquid 2 was produced. The diffusion constant, electrophoretic mobility, and surface tension were 5.0 × 10 ⁻⁸ cm ² / s, −4.9 × 10 ⁻⁴ cm ² / V · s, and 40 mN / m, respectively. When applied by spraying, the wettability with respect to the white glass was poor and unevenness was observed. Further, when an oven-dried film was observed, a uniform film was not formed at the end. In addition, a coating film was produced in the same manner as in Example 1 using a liquid that was maintained at 25 degrees for 30 days after the evaluation liquid 2 was produced. The film thickness and refractive index were 110 nm and 1.40, respectively. Moreover, when the average transmittance | permeability of the board | substrate in 400 nm-700 nm was measured, 3% transmittance | permeability was high compared with the film formation front.

(Comparative Example 4)
Analysis evaluation (diffusion constant, electrophoretic mobility, surface tension) of the liquid was performed in the same manner as in Example 1 using the liquid within 1 hour after producing the evaluation liquid 3. The diffusion constant and surface tension were 3.0 × 10 ⁻⁸ cm ² / s and 31 mN / m, respectively. In addition, a coating film was produced in the same manner as in Example 1 using a liquid within 1 hour after producing the evaluation liquid 1. The film thickness and refractive index were 100 nm and 1.45, respectively. When rubbed with a sponge, the film peeled off immediately and the film strength was weak.

Claims (8)

A film-forming composition comprising a titanium oxide, a silicon oxide, and an organosilicon surfactant, wherein the molar concentration of Si / the molar concentration of Ti is 5 to 20, and the surface against air by a dropping method Arithmetic average the diffusion constants calculated by analyzing the autocorrelation function measured by a dynamic scattering device at a scattering angle of 90 degrees and a temperature of 25 degrees by the cumulant method with a tension of 20 mN / m to 35 mN / m. the average diffusion constant determined Te is ^{6.5 × 10 -8 cm 2 /s~8.0×10 -8} cm 2 / s, at a temperature of 25 ° by electrophoresis laser Doppler method using dynamic scattering device The composition for film formation whose electrophoretic mobility measured is -5.0 * 10 < ^-4 > cm < ² > / V * s--4.0 * 10 < ^-4 > cm < ² > / V * s. The film forming composition according to claim 1, wherein the titanium oxide is of an amorphous type. The composition for film formation according to claim 1 or 2, wherein the titanium oxide is titanium peroxide. Furthermore, the composition for film formation of any one of Claims 1-3 in which the 1 or more element selected from the group which consists of copper, a zirconium, tin, zinc, antimony, and silver is doped. The board | substrate with an antireflection film obtained by apply | coating the composition for film formation of any one of Claims 1-4 to a board | substrate, and heating. The solar cell module with an antireflection film obtained by apply | coating the composition for film formation of any one of Claims 1-4 to a solar cell module, and heating. A method for producing a substrate with an antireflection film comprising a step of applying a film-forming composition comprising a titanium oxide, a silicon oxide, and an organosilicon surfactant to a substrate, wherein the molar concentration of Si / Ti The autocorrelation function obtained by a dynamic scattering apparatus at a scattering angle of 90 degrees and a temperature of 25 degrees with a molar concentration of 5 to 20 and a surface tension by air of 20 mN / m to 35 mN / m. the average diffusion constant determined by arithmetically averaging the diffusion constants calculated by analyzing by the cumulant method is ^{6.5 × 10 -8 cm 2 /s~8.0×10 -8} cm 2 / s, kinematic Electrophoretic mobility measured at 25 ° C. by an electrophoretic laser Doppler method using a mechanical scattering device is −5.0 × 10 ⁻⁴ cm ² / V · s to −4.0 × 10 ⁻⁴ cm ² / V · s coating A step of confirming that the formation composition, a step of applying the coating composition to the substrate, and a heating method of the antireflection film-coated substrate. The manufacturing method of the board | substrate with an antireflection film of Claim 7 whose said board | substrate is a solar cell module in which a solar cell element is laminated | stacked on a glass substrate or a glass substrate.