KR20130096145A - Application solution for formation of coating film for spray application and coating film - Google Patents

Abstract

Provided are an antireflection film forming method capable of easily forming an antireflection film even when irregularities on the back surface of a solar cell and the like cannot be fixed by adsorption, and an antireflection film forming agent used in the method.
The coating liquid for film formation for spray application containing the following component (A), a component (B), and a component (C).
Component (A): polysiloxane which has a fluorine-containing organic group,
Component (B): Glycol ether of 4 to 8 carbon atoms,
Component (C): 1 or more types of solvent chosen from the group which consists of a C3-C10 cyclic alcohol and C3-C10 glycol.

Description

Coating liquid and film for film formation for spray application {APPLICATION SOLUTION FOR FORMATION OF COATING FILM FOR SPRAY APPLICATION AND COATING FILM}

This invention uses the coating liquid for low refractive index film formation which can contain a polysiloxane obtained by polycondensing an alkoxysilane, and can form a uniform film | membrane by spray coating containing a some solvent further, and the coating liquid for film formation It is related with the film formed by this, and also the antireflection material which has this film.

Conventionally, when a film having a low refractive index smaller than the refractive index of the substrate is formed on the surface of the substrate, it is known that the reflectance of light reflected from the surface of the coating is lowered. The low refractive index film which exhibits such a reduced light reflectance is used as a light reflection prevention film, and is applied to the surface of various base materials.

For example, Patent Document 1 adds a tetraalkoxysilane or the like to an alcohol dispersion liquid of MgF ₂ fine particles produced by reacting a magnesium salt or an alkoxymagnesium compound as the Mg source with a fluoride salt as the F source, or a film strength improvement thereto. A method of applying a liquid as a coating liquid, coating it on a glass substrate, heat treatment at a temperature of 100 to 500 ° C, and forming a antireflection film having a low refractive index on the substrate is disclosed.

In addition, Patent Literature 2 discloses a hydrolysis polycondensate such as tetraalkoxysilane, which is a coating liquid by mixing two or more kinds having different average molecular weights and a solvent such as an alcohol to form a coating liquid from the coating liquid. And manufacturing a film by adding means, such as control of relative humidity, are disclosed. The film is obtained by heating at a temperature of 250 ° C. or higher, exhibits a refractive index of 1.21 to 1.40, and has a thickness of 60 to 160 nm having micro pits or irregularities having a diameter of 50 to 200 nm. A film is formed on a glass substrate and low reflection glass is manufactured.

Moreover, Patent Document 3 discloses a low reflectance glass made of glass, an underlayer film having a high refractive index formed on its surface, and an upper layer film having a low refractive index formed on its surface. Formation of the upper layer film includes a fluorine-containing silicon compound having a polyfluorocarbon chain such as CF ₃ (CF ₂ ) ₂ C ₂ H ₄ Si (OCH ₃ ) ₃ , and 5 to 90% by mass of Si (OCH ₃ ) _4. After hydrolyzing the silane coupling agents such as acetic acid in the presence of a catalyst such as acetic acid in an alcohol solvent, the liquid of the co-condensate is prepared by filtration and coated on the underlayer film and heated at a temperature of 120 to 250 ° C. It is carried out by the method.

Further, Patent Document 4 includes a silicon compound represented by Si (OR) ₄ , a silicon compound represented by CF ₃ (CF ₂ ) _n CH ₂ CH ₂ Si (OR ¹ ) ₃ , an alcohol represented by R ² CH ₂ OH, The coating liquid which produces | generates the solution of polysiloxane by heating the reaction mixture containing oxalic acid in a specific ratio in the absence of water at the temperature of 40-180 degreeC is disclosed. The coating liquid is applied to the surface of the substrate and thermally cured at a temperature of 80 to 450 ° C. to form a film having a refractive index of 1.28 to 1.38 and a water contact angle of 90 to 115 degrees.

Generally, as a wet process, spin coat, dip coat, etc. are mentioned as a film-forming method of the low refractive index film on a glass substrate, In fact, spin coat is often used. However, in spin coating, there are problems in that the size of the substrate is limited, the point that the chemical liquid use efficiency is very low, and the like. Moreover, as a dry process, a vacuum vapor deposition method, a CVD method, etc. are mentioned, A productivity, a cost, etc. become a problem in these methods.

Therefore, the spray coating method attracts attention as a coating method with little substrate dependence, and productivity and cost consideration. The spray coating method is a method of dropping fine droplets onto a substrate and forming a film by wet spreading of the liquid. The spray coating method is advantageous in that there is no substrate dependence and the waste of the coating liquid is small. Therefore, cost reduction of the low reflection glass, improvement of production efficiency, etc. are anticipated.

In such a situation, introduction of a process of forming a low refractive index film on a substrate by spray coating is required, and an antireflection film forming agent (coating solution) capable of meeting such a demand is required.

However, the said polysiloxane containing antireflection film forming agent was not necessarily suitable for spray application.

On the other hand, there exists an example in which the coating film was formed by spray coating using glycol ether as a solvent (for example, refer patent document 5). However, in patent document 5, it is the coating material containing microparticles | fine-particles, and serves as an antireflection film by forming unevenness | corrugation from microparticles | fine-particles. Moreover, there is no description that the said coating material contains fluorine-containing polysiloxane.

Japanese Patent Application Laid-Open No. 05-105424 Japanese Laid-Open Patent Publication No. 06-157076 Japanese Laid-Open Patent Publication No. 61-010043 Japanese Patent Application Laid-Open No. 09-208898 Japanese Unexamined Patent Publication No. 2003-202813

SUMMARY OF THE INVENTION An object of the present invention is to provide a coating liquid for forming a silicon-based antireflective coating film that can be formed using a spray coating method, and to provide a low refractive index film having excellent in-plane uniformity of the film by spray coating. .

MEANS TO SOLVE THE PROBLEM The present inventors came to complete this invention shown below as a result of earnestly researching in view of said situation. That is, the present invention has the following points.

1. Coating liquid for film formation for spray application containing the following component (A), component (B), and component (C).

Component (A): polysiloxane which has a fluorine-containing organic group,

Component (B): Glycol ether of 4 to 8 carbon atoms,

Component (C): 1 or more types of solvent chosen from the group which consists of a C3-C10 cyclic alcohol and C3-C10 glycol.

2. Coating liquid for film formation of said 1 whose component (A) is polysiloxane which has a C1-C10 fluorine-containing organic group.

3. Coating liquid for film formation as described in said 1 or 2 whose total molar amount of the fluorine-containing organic group which component (A) has is 5-40 mol with respect to 100 mol of the total molar amount of the silicon atom which component (A) has.

4. Coating liquid for film formation in any one of said 1-3 whose component (C) is 1 or more types of solvent chosen from the group which consists of cyclohexanol, propylene glycol, 1,3 butanediol, and 2,3 butanediol.

5. Coating liquid for film formation in any one of said 1-4 which is polysiloxane obtained by polycondensing alkoxysilane containing component (A) and the alkoxysilane which has a tetraalkoxysilane and a fluorine-containing organic group.

6. The component (A) is of the total amount of the silicon atom in terms of SiO ₂ is 30 to 90 component (B) about 1 part by mass of the mass parts by mass of ingredient (C) 2 ~ 30 parts by mass the 1-5 having Coating liquid for film formation in any one of them.

7. Furthermore, any one of said 1-6 containing (D) component containing 1 or more types of solvents chosen from the group which consists of a glycol ether solvent, a ketone solvent, and an amide solvent in normal pressure which are 100 degreeC or more in normal pressure. Coating liquid for film formation.

8. Coating liquid for film formation of said 7 whose component (D) is 1 or more types of solvent chosen from the group which consists of ethylene glycol monobutyl ether, cyclohexanone, N-methylpyrrolidone, and propylene glycol monobutyl ether.

9. The film obtained using the coating liquid for film formation in any one of said 1-8.

10. An antireflection substrate having the film as described in 9 above.

11. The antireflection film which has a film of 9 above.

12. A solar cell having the film according to 9 above.

13. The film formation method including the process of spray-coating the coating liquid for film formation in any one of said 1-8 to a base material, and forming a coating film.

The coating liquid for film formation of this invention is excellent in film-forming property, and can form the film with high transmittance | permeability. Moreover, the liquid-liquid efficiency in the case of spray coating is also excellent.

In addition, according to the method of the present invention, a low refractive index film having excellent film formation properties and high transmittance can be easily formed even if the back surface of a solar cell or the like has irregularities and cannot be fixed by adsorption.

Hereinafter, the present invention will be described in detail.

The present invention provides at least one member selected from the group consisting of component (A): polysiloxane having an organic group substituted with a fluorine atom in the side chain, component (B): glycol ethers, component (C): cyclic alcohols and glycols It relates to the coating liquid for film formation for spray application containing a solvent.

<Component (A)>

Component (A) is polysiloxane which has the organic group substituted by the fluorine atom in a side chain.

The organic group substituted with such a fluorine atom is an organic group which substituted one part or all part of the hydrogen atom of an aliphatic group or an aromatic group with the fluorine atom. These specific examples are given below.

For example, a trifluoro propyl group, a tridecafluoro octyl group, a heptadeca fluorodecyl group, a pentafluorophenyl propyl group, etc. are mentioned.

Among these, a perfluoroalkyl group is preferable because it is easy to obtain a high transparency film. More preferably, it is a C3-C15 perfluoroalkyl group.

As a specific example, a trifluoropropyl group, a tridecafluoro octyl group, a heptadecafluorodecyl group, etc. are mentioned.

In this invention, you may use together multiple types of polysiloxane which has such a side chain.

The method of obtaining the polysiloxane which has the organic group substituted by the above fluorine atom in a side chain is not specifically limited. Generally, it is obtained by polycondensing the alkoxysilane which has said organic group in a side chain, and other alkoxysilanes.

Especially, the polysiloxane obtained by polycondensing the alkoxysilane represented by Formula (1) and the alkoxysilane represented by Formula (2) is preferable.

[Formula 1]

Si (OR ¹ ) ₄ (1)

(2)

R ² Si (OR ³ ) ₃ (1)

Although R <^1> of Formula (1) shows a hydrocarbon group, since a carbon number has low reactivity, the C1-C5 saturated hydrocarbon group is preferable, More preferably, it is a methyl group, an ethyl group, a propyl group, or a butyl group.

Specific examples of such tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane and the like, which can be easily obtained as commercially available products.

In this invention, although at least 1 type of alkoxysilane represented by Formula (1) may be used, you may use multiple types as needed.

The alkoxysilane represented by Formula (2) is an alkoxysilane which has an organic group substituted by said fluorine atom in a side chain. Therefore, this alkoxysilane provides water repellency to a coating film.

Here, although R <^3> of Formula (2) shows the organic group substituted by said fluorine atom, the number of the fluorine atoms which this organic group has is not specifically limited.

In addition, R <^3> of Formula (2) represents a C1-C5 hydrocarbon group, Preferably it is a C1-C5 saturated hydrocarbon group, More preferably, it is a methyl group, an ethyl group, a propyl group, or a butyl group.

Also in the alkoxysilane represented by such Formula (2), the alkoxysilane which R <^2> is a perfluoroalkyl group is preferable, and the alkoxysilane which R <^2> is an organic group represented by Formula (5) is more preferable.

(3)

CF ₃ (CF ₂ ) _k CH ₂ CH ₂ (5)

In formula (5), k shows the integer of 0-12.

Specific examples of the alkoxysilane having an organic group represented by formula (5) include trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, tridecafluorooctyltrimethoxysilane and tridecafluorooctyl Liethoxysilane, heptadecafluorodecyl trimethoxysilane, heptadecafluorodecyl triethoxysilane, etc. are mentioned.

In particular, when k is an integer of 2 to 12, the wiping property of the fingerprint of the anti-reflection film becomes good, and therefore is preferable.

In this invention, although at least 1 type of alkoxysilane represented by Formula (2) may be used, you may use multiple types as needed.

Moreover, the polysiloxane which is a component (A) may polycondensate the alkoxysilane represented by Formula (1) and Formula (2), and the alkoxysilane represented by Formula (3) and / or Formula (6) other than that. At this time, in addition to the alkoxysilane represented by Formula (1) and Formula (2), any one of the alkoxysilane represented by Formula (3) and the alkoxysilane represented by Formula (6) may be used independently, and may use both together. .

[Formula 4]

R ⁴ _n Si (OR ⁵ ) _4-n (3)

In formula (3), R <^4> represents the organic group which is not substituted by the fluorine atom, R <^5> represents a C1-C5 hydrocarbon group and n represents the integer of 1-3.

[Chemical Formula 5]

(R ⁷ O) ₃ SiR ⁸ Si (OR ⁷ ) ₃ (6)

In formula (6), R <^7> represents a C1-C5 hydrocarbon group and R <^8> represents a C1-C20 divalent organic group.

The alkoxysilane of Formula (3) is an organic group in which R <^4> is not substituted by the fluorine atom, and the alkoxysilane which has 1, 2 or 3 alkoxy groups. R <^5> of Formula (3) is a C1-C5 hydrocarbon group, respectively. When n is 1 or 2, in general, R ⁵ is often the same, but in the present invention, R ⁵ may be the same or different.

R <^4> in Formula (3) is a C1-C20 organic group, Preferably it is a C1-C15 organic group. In the case where n is 2 or 3, in general, R ⁴ is often the same. In the present invention, R ⁴ may be the same or different.

Although the specific example of the alkoxysilane represented by such Formula (3) is shown below, it is not limited to this.

Methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, pentyl Limethoxysilane, pentyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyl Trimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-gly Sidoxif Piltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, γ-methacryl Trialkoxysilanes, such as oxypropyl trimethoxysilane, (gamma)-methacryloxypropyl triethoxysilane, (gamma) -urade propyl trimethoxysilane, and (gamma) -urade propyl triethoxysilane, and dimethyl dimethoxysilane, dimethyl die And dialkoxysilanes such as oxysilane.

R <^5> of Formula (3) is a C1-C5 hydrocarbon group, Preferably it is a C1-C4 saturated hydrocarbon group, More preferably, it is a C1-C3 saturated hydrocarbon group.

In this invention, you may use multiple types of alkoxysilane represented by Formula (3) as needed.

Further, the alkoxysilane of the formula (6), R ⁷ is inde hydrocarbon group of 1 to 5 carbon atoms, preferably a saturated hydrocarbon group having from 1 to 4 carbon atoms, more preferably a saturated hydrocarbon group having a carbon number of 1 to 3.

In this invention, you may use multiple types of alkoxysilane represented by Formula (6) as needed. In general, R ⁷ is often the same, but in the present invention, R ⁷ may be the same or different.

R <^8> is a C1-C20 divalent organic group, A structure is not specifically limited, R8 may contain cyclic structures and branched structures, such as a double bond, a triple bond, and a phenyl group. Moreover, you may contain hetero atoms, such as nitrogen, oxygen, and fluorine.

In the present invention, when it is desired to form a film having better water repellency, among the alkoxysilanes represented by the formula (6), the R ⁸ moiety is an alkoxysilane which is a divalent organic group such as the formula (7) containing a perfluoroalkyl chain. Preference is given to using.

[Formula 6]

-CH ₂ CH ₂ (CF ₂ ) _p CH ₂ CH _2- (7)

In formula (7), p shows the integer of 1-12.

As a specific example of the alkoxysilane of the structure whose R <^8> part of Formula (6) is a divalent organic group containing the perfluoroalkyl chain represented by Formula (7), 1, 6-bis (trimethoxy silyl ethyl) dode Carfluorohexane, 1,6-bis (triethoxysilylethyl) dodecafluorohexane, etc. are mentioned.

The component (A) used for this invention makes an alkoxysilane represented by Formula (1) and Formula (2) essential normally, and if necessary, either one of the alkoxysilane represented by Formula (3) and Formula (6). Or it is obtained by polycondensing both, but if it is a homogeneous solution state in a solvent, the use ratio of these alkoxysilanes is not specifically limited.

When the total molar amount of the fluorinated organic group of the alkoxysilane represented by Formula (2) is 5 mol% or more with respect to the total molar amount of the silicon atoms of the alkoxysilane used for obtaining a component (A), the film whose contact angle of water will be 80 degree or more Since it is easy to obtain, it is preferable, and since it is 40 mol% or less, since generation | occurrence | production of a gel or a foreign material can be suppressed and a homogeneous solution of the component (A) can be obtained easily, it is preferable. Moreover, as for the total molar amount of the fluorine-containing organic group of the alkoxysilane represented by Formula (2), 10-30 mol% is more preferable.

On the other hand, 60-95 mol% is preferable and, as for the usage-amount of the alkoxysilane of Formula (1), in the total usage-amount of all the alkoxysilanes used in order to obtain a component (A), 70-90 mol% is more preferable.

As for the usage-amount in the case of using together the alkoxysilane represented by Formula (3), 0-35 mol% is preferable and, as for the total usage-amount of the alkoxysilane used for obtaining a component (A), 0-10 mol% is more preferable. . Moreover, when using only the alkoxysilane represented by Formula (6) together, 0-20 mol% is preferable and 0-10 mol% is more preferable in the total usage-amount of the alkoxysilane used for obtaining a component (A). . In addition, when using both of the alkoxysilanes represented by Formula (3) and Formula (6) together, the total amount of the alkoxysilane represented by Formula (3) and Formula (6) uses the alkoxy used to obtain component (A). In the total usage-amount of a silane, it is 0-35 mol%, Preferably it is 0-20 mol%, Moreover, the ratio in which the alkoxysilane represented by Formula (6) contains is the alkoxy used in order to obtain a component (A). It is preferable that it is 0-15 mol% in the total usage-amount of a silane, and 0-10 mol% is more preferable.

Although the method of condensing polysiloxane which is a component (A) used for this invention is not specifically limited, For example, the method of hydrolyzing and condensing an alkoxysilane in alcohol or a glycol solvent is mentioned. In that case, any of partial hydrolysis and complete hydrolysis may be sufficient as a hydrolysis-condensation reaction. In the case of complete hydrolysis, theoretically, 0.5 times mole of water of all the alkoxy groups in the alkoxysilane may be added, but an excess amount of water is usually added more than 0.5 times mole.

In this invention, although the quantity of the water used for the said reaction can be suitably selected as desired, Usually, it is 0.1-2.5 times mole of all the alkoxy groups in an alkoxysilane, Preferably it is 0.1-2.0 times mole.

In addition, acids, such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, oxalic acid and maleic acid, are generally used for the purpose of promoting hydrolysis and condensation reactions; Alkali such as ammonia, methylamine, ethylamine, ethanolamine, triethylamine and the like; Metal salts, such as hydrochloric acid, sulfuric acid, or nitric acid, are used as a catalyst. In this case, as for the quantity of the catalyst used for reaction, about 0.001-0.05 times mole of all the alkoxy groups in an alkoxysilane is preferable, and 0.01-0.03 times mole is more preferable. Moreover, it is also common to accelerate a hydrolysis and condensation reaction by heating the solution which the alkoxysilane melt | dissolved. In this case, the heating temperature and the heating time can be appropriately selected as desired. Preferably, the reaction system is set at 50 to 180 ° C so as to prevent evaporation, volatilization, or the like of the liquid, in a closed container or under reflux for several tens of minutes to several tens of hours. do. For example, the method of heating and stirring at 50 degreeC for 24 hours, or heating and stirring for 2 to 10 hours under reflux is mentioned.

Moreover, as another method, the method of heating the mixture of an alkoxysilane, a solvent, and oxalic acid is mentioned, for example. Specifically, oxalic acid is added to the alcohol in advance to form an alcohol solution of oxalic acid, followed by mixing and heating the solution and the alkoxysilane. In that case, it is common that the quantity of oxalic acid shall be 0.2-2 mol with respect to 1 mol of all the alkoxy groups which an alkoxysilane has, Preferably it is 0.5-2 mol. Heating in this method can be performed at liquid temperature of 50-180 degreeC, Preferably it is performed for several tens of minutes-several tens of hours, for example in a closed container or under reflux so that evaporation, volatilization, etc. of a liquid may not occur.

In each of the above methods, when using a plurality of alkoxysilanes, a plurality of alkoxysilanes may be mixed in advance, or a plurality of alkoxysilanes may be added in sequence.

When polycondensation of an alkoxysilane by the above method, it is common that the concentration (hereinafter referred to as SiO ₂ conversion concentration) in which the total amount of silicon atoms of the injected alkoxysilane is converted to SiO ₂ is generally 20 mass% or less, and 15 mass % Or less is preferable. By selecting an arbitrary concentration in such a concentration range, it is possible to suppress the formation of a gel to obtain a homogeneous solution of polysiloxane.

The solvent used when polycondensing the alkoxysilane is not particularly limited as long as it dissolves the alkoxysilane represented by the formulas (1) and (2) and, if necessary, the alkoxysilanes represented by the formulas (3) and (6). . Generally, since alcohol is produced | generated by the polycondensation reaction of an alkoxysilane, the organic solvent with favorable compatibility with alcohols or alcohols is used.

As a specific example of such an organic solvent, Alcohol, such as methanol, ethanol, a propanol, butanol; Ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether and diethylene glycol monoethyl ether; Ketones, such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, etc. are mentioned.

In this invention, you may mix and use multiple types of said organic solvent.

Hereinafter, in a component (B) and a component (C), carbon number means the number of all the carbon atoms contained in 1 molecule.

<Component (B)>

Component (B) used for this invention is a C4-C8 glycol ether.

As the component (B) used in the present invention, for example, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethyl carbitol, butyl carbitol, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol Monobutyl ether etc. are mentioned.

In the present invention, the component (B) is not limited as long as it is compatible with the component (A) satisfactorily, and plural kinds thereof may be used.

Component (B) content in the coating liquid for forming a coating film of the ingredient (A) is a 30 to about a total amount of silicon atoms per 1 part by mass of SiO ₂ in terms of a mass 90 parts by mass with, preferably 40 to 80 parts by mass It is part, Especially preferably, it is 50-75 mass parts.

<Component (C)>

Component (C) of this invention is 1 or more types of solvent chosen from the group which consists of a C3-C10 cyclic alcohol and C3-C10 glycol. As a solvent which is a component (C), if a component (A), a component (B), and the other component mentioned later as needed are melt | dissolved uniformly, it will not specifically limit.

As a specific example of the solvent which is a component (C), Glycols, such as propylene glycol, 1,3 butanediol, 2,3 butanediol, hexylene glycol; And cyclic alcohols such as cyclopropanol, cyclobutanol, cyclopentanol, cyclohexanol, 2-methylcyclohexanol, cycloheptanol, cyclooctanol, cyclononanol, and cyclodecanol. Especially, cyclohexanol, propylene glycol, 1,3 butanediol, 2,3 butanediol etc. are preferable from a viewpoint of applicability | paintability.

As the component (C), one type selected from the above solvents may be used, or a plurality thereof may be mixed and used.

Coating content of the coating liquid for formation of the component (C), component (A) is and the total amount of the silicon atoms from 2 to 30 parts by weight for 1 part by mass of SiO ₂ in terms of a mass having preferably 2 to 20 parts by mass It is part, Especially preferably, it is 5-10 mass parts.

In addition, the coating liquid for film formation of this invention may contain a component (D) in addition to the said component.

<Component (D)>

There is no restriction | limiting in particular as a component (D) as long as the solubility of a component (A) is high and a boiling point is 100 degreeC or more. As such a solvent, a glycol ether solvent, a ketone solvent, and an amide solvent are mentioned, for example, Ethylene glycol monobutyl ether, cyclohexanone, N-methylpyrrolidone, and a propylene glycol monobutyl ether are mentioned as a specific example. Can be mentioned.

Component coating content in the coating liquid for formation of the (D), the component (A) is and the total amount of the silicon atoms from 0 to 50 parts by weight for 1 part by mass of SiO ₂ in terms of a mass having preferably 5 to 40 mass It is part, Especially preferably, it is 10-30 mass parts.

It is preferable from a viewpoint that the coating liquid for film formation contains a component (D) from the viewpoint of raising the liquid-solution efficiency with respect to the base material at the time of spray coating.

&Lt; Other components >

In the present invention, other components other than the component (A), the component (B), the component (C), and the component (D), for example, inorganic fine particles, fillers, leveling, so long as the effects of the present invention are not impaired. The agent, such as a surface modifier and surfactant, may be contained.

Examples of the inorganic fine particles include metal oxide fine particles, metal double oxide fine particles, magnesium fluoride fine particles, and the like.

Examples of the metal oxide fine particles include fine particles such as silica, alumina, titanium oxide, zirconium oxide, tin oxide, and zinc oxide.

Examples of the metal double oxide fine particles include fine particles such as ITO (Indium Tin Oxide), ATO (Antimony Trioxide), AZO (Zinc Aluminum Oxide), and Zinc Antimonate. have.

Moreover, hollow silica fine particles, porous silica fine particles, etc. can also be illustrated.

The inorganic fine particles may be either a powder or a colloidal solution, but a colloidal solution is preferable because it is easy to handle. This colloidal solution may disperse | distribute inorganic fine particle powder in a dispersion medium, and may be a colloidal solution which is a commercial item.

In this invention, by containing an inorganic fine particle, it becomes possible to provide the surface shape of the cured film formed, or another function.

As inorganic fine particles, it is preferable that the average particle diameter is 0.001-0.2 micrometer, More preferably, it is 0.001-0.1 micrometer. When the average particle diameter of an inorganic fine particle exceeds 0.2 micrometer, transparency of the hardened film formed according to the coating liquid prepared may fall.

Examples of the dispersion medium of the inorganic fine particles include water and an organic solvent. As a colloidal solution, it is preferable that pH or pKa is adjusted to 2-10 from a viewpoint of stability of the coating liquid for film formation, More preferably, it is 3-7.

As an organic solvent used for the dispersion medium of a colloidal solution, Alcohol, such as methanol, ethanol, a propanol, butanol; Glycols such as ethylene glycol; Ketones such as methyl ethyl ketone and methyl isobutyl ketone; Aromatic hydrocarbons such as toluene and xylene; Amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone; Esters such as ethyl acetate, butyl acetate and γ-butyrolactone; Ethers, such as ethylene glycol monopropyl ether, tetrahydrofuran, and 1, 4- dioxane, are mentioned. Of these, alcohols and ketones are preferred. These organic solvents may be used alone or as a dispersion medium by mixing two or more kinds thereof.

Moreover, a well-known thing can be used for a filler, a leveling agent, a surface modifier, surfactant, etc., Especially since a commercial item is easy to obtain, it is preferable.

&Lt; Coating liquid for forming a film &

The method of preparing the coating liquid for film formation of this invention is not specifically limited. When component (A), component (B), and component (C) or component (D) are added, the solution which component (A), component (B), component (C), and component (D) are uniform If it is a state. Usually, since component (A) is polycondensed in a solvent, it is obtained in a solution state. Therefore, using the solution containing component (A) (henceforth a solution of component (A)) as it is, mixing a component (B) and a component (C), or adding a component (D) In that case, the method of mixing with component (D) again is easy. Moreover, if necessary, after concentrating the solution (A) of a component, diluting by adding a solvent, or substituting with another solvent, mixing a component (B) and a component (C), or adding a component (D) In that case, you may mix with a component (D) again. Moreover, after mixing the solution of component (A), a component (B), and a component (C), or when adding a component (D), after mixing a component (D) again, you may add a solvent. . Moreover, after melt | dissolving a component (B) in the solvent which is a component (C), you may mix with the solution of component (A), and may add a component (D) again.

In terms of the total amount of silicon atoms has a film of coating liquid for forming the component (A) to the SiO ₂ concentration (SiO ₂ converted concentration) is 0.1 to 15 mass% is preferred, more preferably 0.3 ~ 6% by weight. If the SiO ₂ conversion concentration is lower than 0.5% by mass, it is difficult to obtain the desired film thickness by one coating. However, in the case of the spraying method, since the coating can be performed a plurality of times, the mass may be less than 0.5% by mass. On the other hand, when it is higher than 15 mass%, the storage stability of a solution will run short easily.

The solvent used for dilution, substitution, etc. may be the same solvent as what was used for polycondensation of said alkoxysilane, and other solvent may be sufficient as it. The solvent is not particularly limited as long as the compatibility of the component (A) and the component (B) is not impaired, and one or a plurality of solvents may be used.

The method of mixing said other components may be simultaneous with a component (A) and a component (B), and may be after mixing of a component (A) and a component (B), and is not specifically limited.

In this invention, the specific example of the coating liquid for film formation is given to the following.

[1] Consists of polysiloxane having a fluorine-containing organic group as the component (A), a glycol ether having 4 to 8 carbon atoms as the component (B) and a cyclic alcohol having 3 to 10 carbon atoms as the component (C) and a glycol having 3 to 10 carbon atoms Coating liquid for film formation containing 1 or more types of solvent chosen from the group.

[2] In addition to the above [1], as a component (D), a film is formed containing at least one solvent selected from the group consisting of a glycol ether solvent, a ketone solvent and an amide solvent having a boiling point of 100 ° C. or higher at normal pressure. Coating liquid.

[3] A coating liquid for film formation containing at least one selected from the group consisting of the above [1] or [2], a filler, a leveling agent, a surface modifier, and a surfactant.

<Formation of film>

The coating liquid for film formation of this invention can be apply | coated to a base material, and a desired film can be obtained by thermosetting.

As a method at the time of coating, the spray coating method is a method of dropping fine droplets onto a substrate and forming a film by wetted liquid, and there is an advantage that there is no substrate dependence and there is no waste of the coating liquid.

The coating liquid for film formation of this invention is the dip coating method, the flow coating method, the spin coating method, the flexographic printing method, the inkjet coating method, the bar coating method, the gravure roll coating method, the roll coating method, the blade coat, for example. Law, air doctor coat, air knife coat, wire coat coat, reverse coat coat, transfer roll coat coat, micro gravure coat coat, kiss coat coat, cast coat coat, slot orifice coat coat, calender coat coat, die coat coat Although it is applicable also to well-known or well-known methods, such as a method, the coating liquid for film formation of this invention is characterized by the point which is especially suitable with respect to the spray coating method.

As a base material, well-known or well-known base materials, such as plastic, glass, and ceramics, are mentioned. As plastic, polycarbonate, poly (meth) acrylate, polyether sulfone, polyarylate, polyurethane, polysulfone, polyether, polyether ketone, trimethyl pentene, polyolefin, polyethylene terephthalate, (meth) acrylonitrile And plates such as triacetyl cellulose, diacetyl cellulose, acetate butyrate cellulose, and the like.

For example, the base material which has unevenness | corrugation on the back surface, such as a solar cell, and cannot be fixed by adsorption has a big advantage by spray coating.

The said uniform film thickness obtained by the spray coating method can be adjusted according to chemical | medical solution amount, gas flow volume, nozzle / stage distance (distance of a nozzle and a stage), an application | coating speed, etc.

The chemical liquid amount is a parameter for determining the film thickness. The film thickness becomes thicker by increasing the chemical liquid amount, and the film thickness becomes thinner by decreasing. In spray coating, the chemical liquid amount is, for example, 1 to 20 ml (milliliter) / min, and preferably 3 to 12 ml / min.

The gas flow rate is a parameter for forming fine droplets, and examples of the gas to be used include N ₂ and dry air, but are not particularly limited thereto. In spray coating, the gas flow rate is, for example, 3 to 20 liters (liter) / min, and preferably 6 to 12 liters / min.

The nozzle / stage distance is a parameter related to the film thickness and the coating property. The closer the distance is, the thicker the film thickness becomes, but it is more likely to cause coating unevenness, and the film thickness becomes thinner by the distance. From the viewpoint of film thickness and applicability, the nozzle / stage distance is 40 to 200 mm, for example, preferably 50 to 100 mm.

The application rate is a parameter related to the film thickness. As the speed increases, the film thickness becomes thin, and when it is late, the film thickness becomes thick. In spray application, the application rate is, for example, 100 to 2000 mm / s, and preferably 300 to 1000 mm / s.

The thickness of the film formed on the substrate, can be controlled depending on parameters such as the time of the application, it can also be easily adjusted according to the SiO ₂ in terms of the concentration of the coating liquid.

A film is obtained by heating the coating film formed on the base material at 100-450 degreeC. Heating can be performed by using a conventional method, for example, a hotplate, oven, a belt furnace, etc. The film thus obtained has the characteristics that the film formability is good and the transmittance is high. Moreover, the film formed by the coating liquid for film formation of this invention can be used especially suitably as a low refractive index layer for solar cells.

When using the film obtained by the method of this invention as antireflection, the method of this invention on the surface of base materials which have a refractive index higher than the refractive index of the said film, for example, normal glass, a TAC (triacetylcellulose) film, etc. By forming a film according to this, this base material can be easily converted into the base material which has a light reflection prevention ability. In that case, although the said film is effective as a single film on the surface of a base material, it is also effective as an antireflective laminated body in which the film was formed on the lower layer film which has high refractive index.

Here, the relationship between the thickness of a film and the wavelength of light is described.

D = (2b-1) λ / 4a (wherein b is an integer of 1 or more) between the thickness d (nm) of the film having the refractive index a and the wavelength λ (nm) of the light for which the reflectance of the film is to be decreased. It is known that the relation of Therefore, by determining the thickness of the film using this equation, it is possible to easily prevent reflection of light of a desired wavelength.

For example, in order to form the film which has a refractive index of 1.32 with respect to the light of wavelength 550nm, and to prevent the reflected light from a glass surface, the optimal film thickness is substituted by substituting these numerical values into (lambda) and a of said formula. Can be calculated. In that case, b should just substitute arbitrary positive integers. For example, the film thickness obtained by substituting 1 into b is 104 nm, and the film thickness obtained by substituting 2 into b is 312 nm. By employing the film thickness calculated in this manner, the antireflection performance can be easily provided.

The coating liquid for film formation of this invention is excellent in film-forming property, and can form the film with high transmittance | permeability. Moreover, the liquid-liquid efficiency in the case of spray coating is also excellent. Therefore, glass tube made of glass; Displays such as televisions, computers, car navigation systems and mobile phones; A mirror having a glass surface; It can use suitably for the field | area where reflection prevention of light, such as a glass showcase and a solar cell, is calculated | required. In particular, polarizers such as liquid crystal displays, plasma displays, projection displays, EL (Electro Luminescence) displays, surface-conduction electron-emitter displays (SEDs), field emission displays (FETs), cathode ray tubes (CRTs), solar cells, and the like. It is useful for antireflective films used in faceplates.

Example

Hereinafter, although a synthesis example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not interpreted limited to these following synthesis examples and an Example.

The abbreviation of the compound in a present Example is as follows.

TEOS: tetraethoxysilane

UPS: 3-ureidopropyltriethoxysilane

FS-13: tridecafluoroctyltrimethoxysilane

MeOH: Methanol

IPA: Isopropyl Alcohol

PG: Propylene glycol

cHexOH: cyclohexanol

BuOH: Butanol

PGME: Propylene Glycol Monomethyl Ether

HG: Hexylene Glycol

EG: ethylene glycol

BCS: Ethylene Glycol Monobutyl Ether

DEDM: diethylene glycol dimethyl ether

DEDE: diethylene glycol diethyl ether

1,3BD: 1,3-butanediol

2,3BD: 2,3-butanediol

PB: Propylene Glycol Monobutyl Ether

PGEE: Propylene Glycol Monoethyl Ether

CHN: cyclohexanone

NMP: N-methylpyrrolidone

The measurement of the remaining alkoxysilane monomer was performed by the following method.

[Residual Alkoxysilane Monomer Measurement Method]

The remaining alkoxysilane monomer in the solution of polysiloxane which is component (A) was measured by gas chromatography (henceforth GC).

GC measurement was measured on condition of the following using Shimadzu GC-14B by Shimadzu Corporation.

Column: Capital column CBP1-W25-100 (length 25 mm, diameter 0.53 mm, thickness 1 μm),

Column temperature: It heated up at 15 degreeC / min at 50 degreeC of start temperature, and set it as the arrival temperature of 290 degreeC (holding time 3 minutes).

Sample injection amount: 1 μl, injection temperature: 240 ° C., detector temperature: 290 ° C., carrier gas: nitrogen (flow rate 30 ml / min), detection method: FID (Flame Ionization Detector) method.

[Synthesis Example]

31.9 g of methanol was added to the four neck reaction flask provided with the reflux tube, and 18.0 g of oxalic acid was added little by little under stirring, and the methanol solution of oxalic acid was prepared. Then, while heating and refluxing the solution, a mixture of TEOS (16.7 g), FS-13 (7.0 g), UPS (1.3 g), and MeOH (25.1 g) was added dropwise thereto. After dropping, the mixture was refluxed for 5 hours, cooled to room temperature to prepare a solution (PS) of polysiloxane of component (A). The alkoxysilane monomer was not detected when the solution (PS) of this polysiloxane was measured by GC.

[Examples 1-24 and Comparative Examples 1-11]

In the composition shown in Table 1, the solution of the polysiloxane obtained by the said synthesis example, and the organic solvent were mixed, and the coating liquid for film formation (Q1-Q24) was prepared.

Moreover, in the comparative example, the coating liquids (T1-T11) were prepared by the composition shown in Table 2.

<Coating Formation Method>

Coating liquids for film formation (Q1 to Q24 and T1 to T11) were used on a soda-lime glass (glass thickness of 0.7 mm) using STS200 manufactured by YD Mechatro Solutions Co., Ltd., and chemical solution 3 ml / min, N ₂ flow rate 10 l / min And the nozzle / stage distance of 70 mm were apply | coated by changing the application | coating speed, and the coating film was formed. Thereafter, the mixture was left at a temperature of 23 ° C. for 1 minute, and then cured at 150 ° C. for 30 minutes in a clean oven to obtain a 100 nm film.

<Film forming evaluation>

The cured film was visually confirmed under an interference pattern inspection lamp manufactured by Funitec and under a white fluorescent lamp. (Circle) that there is no nonuniformity, (circle) that there is almost no nonuniformity, and (triangle | delta) and a thing with some nonuniformity were made into (circle). The evaluation results are shown in Table 3 and Table 4.

<Transmittance Measurement>

Using a spectrophotometer UV3100PC manufactured by Shimadzu Corporation, light having a wavelength of 400 to 800 nm was incident on the cured film, and the transmittance was measured. An evaluation result is shown by the specific transmittance which subtracted the value of a base material from the measured value, and shows the result in Table 3 and Table 4.

In addition, the specific transmittance | permeability in Table 3 and Table 4 shows the percentage of the transmittance | permeability improved when the film | membrane of this invention was formed on soda-lime glass from the transmittance | permeability of soda-lime glass as a percentage. In addition, it was set as x that the improvement of the transmittance | permeability was not confirmed.

As shown in Table 3, in Examples 1-24, the evaluation result of film forming property showed the outstanding applicability | paintability whose (circle) is more than (circle) under an interference fringe test lamp, (double-circle) under white light, and the film's specific transmittance is 3%.

On the other hand, in Comparative Examples 1-11, as shown in Table 4, the evaluation result of film forming property is (triangle | delta) or less, and it became inadequate that the specific transmittance of a film is also 1% or less.

<Coating Formation Method>

Chemical solution 3 ml / min, N using coating liquid for film formation (Q1, Q17, Q19, Q21, and Q23) on soda-lime glass (glass thickness 0.7mm) using STS-200 by YD Mechatro Solutions, Inc. _{It applied at 2} flow rates of 10 L / min, a nozzle / stage distance of 70 mm, and an application rate of 300 mm / s to form a coating film. Then, after leaving it for 1 minute at the temperature of 23 degreeC, it hardened | cured for 30 minutes at 150 degreeC in the clean oven, and obtained the film.

<Measurement of film thickness>

Using the F20-EXR by FILMETRICS, the hardened film was measured for thickness in 16 planes, and the average value was computed. The results are shown in Table 5.

As shown in Table 5, in the spray coating on the same conditions, in Example 25, the film thickness was 95 nm, but in Examples 26-29, it was confirmed that the film thickness is about 10 nm or more thick. Since the film thickness of the film obtained by the same parameter became thick, it was confirmed that the liquid-liquid efficiency improved by containing a component (D).

<Coating Film Formation Method on Solar Cell Module>

Coating liquids (Q1, and Q17) for film formation were chemical liquid 3 ml / min, N ₂ flow rate 10 L / min, nozzle / stage distance, using STS-200 manufactured by YD Mechatro Solutions Co., Ltd. on a crystalline silicon solar cell module. It applied at 70 mm and application | coating speed 300 mm / s, and formed the coating film. Then, after leaving it for 1 minute at the temperature of 23 degreeC, it hardened | cured for 30 minutes at 150 degreeC in the clean oven, and obtained the film.

<Solar cell IV measurement evaluation method>

Solar cell IV measurement evaluation was performed using the Yamashita electric field-made solar simulator YSS-150. The IV measurement data obtained by irradiating the module which mixed the ultraviolet-infrared light of wavelength 290-1400nm with the module 6 times at the temperature of 25 degreeC was averaged. Table 6 shows the results of conversion efficiency of the solar cell calculated from the obtained data.

In Table 6, "Isc" means "short circuit current" and "conversion efficiency" means the efficiency of conversion with respect to the electric power of sunlight.

As shown in Table 6, Examples 30 and 31 showed 3% (0.5% of conversion efficiency) in specific conversion efficiency compared with the comparative example 12 which is a module which is not apply | coated, and the outstanding result was shown.

Industrial availability

The coating liquid for film formation of this invention is suitable for spray application, for example, it is very useful because an anti-reflective film can be formed easily, even if there is an unevenness | corrugation on the back surface of a solar cell etc., and cannot be fixed by adsorption.

In addition, the JP Patent application 2010-105344, the claim, and all the content of the abstract for which it applied on April 30, 2010 are referred here, and it takes in as an indication of the specification of this invention.

Claims (13)

The coating liquid for film formation for spray application containing the following component (A), a component (B), and a component (C).
Component (A): polysiloxane which has a fluorine-containing organic group,
Component (B): Glycol ether of 4 to 8 carbon atoms,
Component (C): 1 or more types of solvent chosen from the group which consists of a C3-C10 cyclic alcohol and C3-C10 glycol. The method of claim 1,
Coating liquid for film formation whose component (A) is polysiloxane which has a C1-C10 fluorine-containing organic group. 3. The method according to claim 1 or 2,
The coating liquid for film formation whose total molar amount of the fluorine-containing organic group which a component (A) has is 5-40 mol with respect to 100 mol of the total molar amount of the silicon atom which a component (A) has. The method according to any one of claims 1 to 3,
Coating liquid for film formation whose component (C) is 1 or more types of solvent chosen from the group which consists of cyclohexanol, propylene glycol, 1,3 butanediol, and 2,3 butanediol. The method according to any one of claims 1 to 4,
Coating liquid for film formation whose component (A) is polysiloxane obtained by polycondensing the alkoxysilane containing the tetraalkoxysilane and the alkoxysilane which has a fluorine-containing organic group. 6. The method according to any one of claims 1 to 5,
Component (A) is the component (B) to the total amount of silicon atoms per 1 part by mass of SiO ₂ in terms of a mass from 30 to 90 parts by weight, (C) component is 2-30 parts by mass with coating liquid for forming a coating film. 7. The method according to any one of claims 1 to 6,
Furthermore, the coating liquid for film formation containing 1 or more types of solvent chosen from the group which consists of a glycol ether solvent, a ketone solvent, and an amide solvent whose boiling point in normal pressure is 100 degreeC or more as a component (D). The method of claim 7, wherein
The coating liquid for film formation whose (D) component is 1 or more types of solvent chosen from the group which consists of ethylene glycol monobutyl ether, cyclohexanone, N-methylpyrrolidone, and propylene glycol monobutyl ether. The film obtained using the coating liquid for film formation in any one of Claims 1-8. The antireflection base material which has a film of Claim 9. The antireflection film which has a film of Claim 9. The solar cell which has a film of Claim 9. The film formation method including the process of spray-coating the coating liquid for film formation in any one of Claims 1-8 to a base material, and forming a coating film.