JP2003119409A - Silica-based coating film foaming solution, method for producing the same, silica-based coating film and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a silica-based coating film forming solution which can eliminate the need for a catalytic addition or a heat treatment process and can form a silica-based coating film even at a room temperature, to provide a method for producing the same, to prepare the silica-based coating film having excellent durability, and to provide a method for producing the same. SOLUTION: The silica-based coating film forming solution has excellent reactivity with a substrate due to its constitution including a nonaqueous organic solvent and a chlorosiloxane oligomer. The silica-based coating film 13 having excellent durability, or the like, can be produced by coating the surface of the substrate 11 with the silica-based coating film forming solution in a dry atmosphere and taking out the substrate to a water-containing atmosphere without the catalytic addition and heat treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solution for forming a silica film, which is preferably used for an insulating film, a flattening film, a protective film, etc. in a semiconductor device, a liquid crystal display device, etc., and a method for producing the same. The present invention relates to a silica-based coating produced by using the same and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, in the case of improving the hardness of the surface of a soft base material such as plastic, a hard coat film has been formed on the surface of the base material. Examples of such a hard coat film include a silica coating formed by a sol-gel method.

As a method for forming a silica film by the sol-gel method, first, an acid catalyst is added to an alcohol solution in which an alkoxysilane compound such as tetraethoxysilane is dissolved, and the alkoxysilane compound is dealcoholized under the acid catalyst. A reacted silica coating forming solution is prepared. Next, this silica coating forming solution is applied to a substrate, and then the substrate is heat-treated at a predetermined temperature to form a silica coating. In this method, an acid catalyst is added to lower the required firing temperature.

[0004]

However, the above-mentioned conventional method for producing a silica coating film has the following problems.

First, in the above-mentioned conventional solution for forming a silica film, when an acid catalyst is added in advance, the catalytic activity of the acid catalyst is lowered, and the pot life of the solution for forming a silica film is shortened. is there. For this reason, there is a problem that the acid catalyst must be added immediately before using the above silica coating forming solution, which makes the manufacturing process troublesome.

Further, in the above-mentioned conventional manufacturing method, the baking temperature was lowered by adding a catalyst, but the baking temperature was still in a high temperature range, so that it could not be used for a base material made of plastic or the like. That is, the conventional method has a problem that the usable substrate is limited. Moreover, it was necessary to set the heat treatment conditions according to the material of the base material. Further, it goes without saying that a heating device is required to carry out the heat treatment process, which causes an increase in manufacturing cost. Further, there are various problems such that the heat treatment process itself is not energy saving.

Further, since the viscosity of the silica coating forming solution is low, the coating properties are poor, and as a result, it is difficult to form a thick silica coating.

The present invention has been made in view of the above conventional problems, and an object thereof is to eliminate the need for a catalyst addition and a heat treatment step and to provide a thick silica coating excellent in film forming property even at room temperature. It is to provide a solution for forming a silica coating that can be formed, a method for producing the same, and a method for producing the silica coating.

[0009]

Means for Solving the Problems The inventors of the present application have made intensive studies on a solution for forming a silica-based coating film and a method for producing the same in order to solve the above conventional problems. As a result, they have found that a silica-based coating film forming solution containing an organic solvent and a chlorosiloxane compound has excellent reactivity with a substrate, and completed the present invention.

Further, in order to solve the above-mentioned problems of the related art, the present inventors have earnestly studied a silica-based coating film formed by using the above-mentioned solution for forming a silica-based coating film and a method for producing the same. As a result, a silica-based coating formed on the surface of the substrate through a siloxane bond, which has a siloxane bond with the above-mentioned substrate through a dehydrochlorination reaction and does not contain a hydrocarbon group in its chemical structure, is formed. The inventors have found that the present invention is excellent in abrasion resistance, scratch resistance, etc., and that such a silica-based coating can be produced without performing a heat treatment step, and thus completed the present invention.

In order to solve the above problems, the solution for forming a silica-based coating film of the present invention has the following constitution.

(1) The solution for forming a silica-based coating film according to the first aspect of the present invention comprises an organic solvent and a siloxane compound having an activating group.

According to the above constitution, since a large number of activating groups are present in the siloxane compound, the activating group and the activating hydrogen are added to the substrate having a functional group having active hydrogen on the surface. It can be chemically adsorbed by reacting with a functional group that it has. Therefore, according to the above configuration, it is possible to provide a silica-based film-forming solution having excellent reactivity with the base material, as compared with a silica-based film-forming solution produced by a conventional sol-gel method or the like. . still,
The term “activating group” means a functional group that exhibits reactivity with a functional group having active hydrogen. The functional group having active hydrogen means, for example, a hydroxyl group (—OH) or an imino group (> NH).

Examples of the siloxane compound having an activating group include those containing a compound represented by the following general formula (I).

[0015]

[Chemical 4] (In the formula, R ^{1 to} R ⁴ may be independently crosslinked by forming a hydrogen atom, a halogen, an isocyanate group, a hydroxyl group, a chlorosilyl group, a dichlorosilyl group, a trichlorosilyl group, a silanol group and a siloxane bond. Represents a silicon-containing functional group, R ⁵ and R ⁶ each independently represent a hydrogen atom, a halogen, an isocyanate group and a hydroxyl group, and m is an integer of 1 or more.) Further, the siloxane having an activating group described above. The compound may be chlorosiloxane.

Further, the chlorosiloxane can be a chlorosiloxane oligomer.

Further, the above chlorosiloxane oligomer has the following general formula (II), general formula (III) and general formula (I
It can be at least one compound selected from the compounds represented by V).

[0018]

[Chemical 5] (In the formula, n is an integer of 1 or more.)

[0019]

[Chemical 6] (In the formula, n is an integer of 1 or more.)

[0020]

[Chemical 7] (In the formula, n is an integer of 1 or more.) As the organic solvent, a non-aqueous organic solvent can be used. Here, the term "non-aqueous organic solvent" means an organic solvent that does not contain a substance having active hydrogen, such as water as an impurity, and that does not react with a silane compound having an activating group.

Further, as the non-aqueous organic solvent, at least one organic solvent selected from a hydrocarbon organic solvent, a fluorine organic solvent and a chlorine organic solvent can be used.

According to the above constitution, use is made of a single organic solvent or a mixture of two or more organic solvents selected from among hydrocarbon-based organic solvents, fluorine-based organic solvents and chlorine-based organic solvents that absorb less water. As a result, it is possible to prevent the dehydrochlorination reaction between the activating group in the siloxane compound and the water, and to provide a silica-based film-forming solution having excellent reactivity with the base material as described above. .

Further, the above silica-based film forming solution contains
Further, an alkoxysilane compound may be contained.

As the alkoxysilane compound, at least one compound selected from tetraethoxysilane and propyloxysilane can be used.

The method for producing a solution for forming a silica-based coating film of the present invention corresponding to the above-mentioned first aspect is a first mixed solution in which a silane compound having an activating group is dissolved in a first organic solvent in a dry atmosphere. And a step of producing an oligomerizing agent for oligomerizing the silane compound having the activating group,
The method is characterized by including a step of preparing a second mixed solution by mixing with a second organic solvent, and a step of mixing the first mixed solution and the second mixed solution in a dry atmosphere.

According to the above method, since the silane compound having an activating group is dissolved in a dry atmosphere when the first mixed solution is formed, the activating group in the silane compound has a moisture content in the atmosphere. It is possible to prevent the dehydrochlorination reaction from occurring and to prevent the reaction activity of the silane compound having an activating group from being impaired. Furthermore, since the first mixed solution and the second mixed solution are mixed in a dry atmosphere, the silane compound having an activating group reacts with the oligomerizing agent contained in the second mixed solution. Therefore, since the silane compound does not cause a dehydrochlorination reaction with excess moisture contained in the atmosphere,
A siloxane compound containing a large amount of activated groups is produced. As a result, it is possible to produce a silica-based film-forming solution having excellent reactivity with a substrate having a functional group having active hydrogen.

The above oligomerizing agent reacts with a silane compound having an activating group dissolved in the first mixed solution to form a siloxane compound having a degree of polymerization of an oligomer and having an activating group. Means a substance that causes

The molar ratio of the oligomerizing agent to the silane compound having an activating group is preferably equimolar or less.

Water can be used as the oligomerizing agent.

As the silane compound having an activating group, at least one compound selected from tetrachlorosilane, trichlorosilane, dichlorosilane, hexachlorodisiloxane and octachlorotrisiloxane can be used.

As the first organic solvent and the second organic solvent, at least one organic solvent selected from hydrocarbon organic solvents, fluorine organic solvents and chlorine organic solvents can be used.

The silica-based coating of the present invention, which corresponds to the first aspect, is a silica-based coating formed on the surface of a substrate through a siloxane bond, and a hydrocarbon is included in the chemical structure of the silica-based coating. The structure does not include a group.

According to the above structure, the silica-based coating is formed by forming a siloxane bond with the surface of the base material, and has excellent adhesion to the base material. Further, in the conventional sol-gel method using, for example, an alkoxysilane compound as a raw material, a silica-based coating film composed of molecules having side chains such as hydrocarbon groups (specifically, for example, methyl groups) was formed. However, the silica-based coating according to the present invention does not include impurities such as hydrocarbon groups in its chemical structure. Therefore, it is extremely high in purity and excellent in hardness and transparency.

Here, the silica-based coating may be configured to include a repeating structural unit represented by the following structural formula (V).

[0035]

[Chemical 8] As a result, the film structure of the silica-based coating can be made to have a mesh structure, and can be made excellent in abrasion resistance and scratch resistance.

The above-mentioned substrate can be a substrate having a functional group having active hydrogen on its surface and having a heat resistance of 150 ° C. or less. Here, "heat resistance is 150 ℃
"Is the following", the physical shape of the substrate with the heat treatment,
The temperature range where its chemical properties do not change is 150 ° C
It means that

The method for producing a silica-based coating film corresponding to the first aspect comprises a coating step of coating the surface of the substrate with the above-mentioned solution for forming a silica-based coating film in a dry atmosphere, and evaporating the non-aqueous organic solvent. And a silica-based coating forming step of forming a silica-based coating on the surface of the base material by bringing the siloxane compound coating into contact with water molecules to form a siloxane compound coating having an activating group. .

According to the above method, the solution for forming a silica-based coating film is applied to the surface of the base material so that the activating group in the siloxane compound and the functional group having active hydrogen existing on the surface of the base material are combined. To react with each other to chemically adsorb the siloxane compound. As a result, a siloxane compound film having an activating group can be formed on the surface of the base material. Furthermore,
By reacting the siloxane compound coating with water molecules, the activating group in the siloxane compound and the hydroxyl group in the water molecules react to form a silica-based coating. Therefore, unlike the conventional sol-gel method, the silica-based coating can be formed very easily without adding a catalyst or performing a heat treatment step.

The silica-based film forming step may be performed in an atmosphere containing water.

Further, a heat treatment step of heating at a temperature of 100 ° C. or higher may be included after the silica-based film forming step.

(2) The solution for forming a silica-based coating film according to the second aspect of the present invention contains a non-aqueous organic solvent and a compound in which a silane compound having an activating group is bonded to anhydrous silica fine particles. Composed.

According to the above construction, by adding anhydrous silica fine particles to the silica-based coating film forming solution, the viscosity thereof can be improved and the coating property can be improved. In addition, the silane compound having the above-mentioned activating group has a siloxane bond (--SiO 2) with the anhydrous silica fine particles.
-) Is connected. This is because the surface of the anhydrous silica fine particles has a functional group having active hydrogen, and this functional group and the activating group have reacted with each other.

Further, since a large number of activating groups are present in the compound obtained by binding the above-mentioned silane compound to the anhydrous silica fine particles, a substrate having a functional group having active hydrogen on its surface is This activating group can react with a functional group having active hydrogen for chemisorption. Therefore, according to the above configuration, it is possible to provide a silica-based film-forming solution having excellent reactivity with the base material, as compared with a silica-based film-forming solution produced by a conventional sol-gel method or the like. .

Here, the term "anhydrous silica fine particles" means
It means fine silica particles from which adsorbed water existing on the surface has been removed, and the surface thereof has a functional group having active hydrogen. The term “non-aqueous organic solvent” means an organic solvent that does not contain a substance having active hydrogen, such as water as an impurity, and that does not react with a silane compound having an activating group. Furthermore, the term "activating group" means a functional group that is reactive with a functional group having active hydrogen. The functional group having active hydrogen is, for example, a hydroxyl group (-OH) or an imino group (> N).
H) etc. are meant.

Further, in the above silica-based film forming solution, it is possible to contain titanium oxide fine particles instead of anhydrous silica fine particles.

Examples of the silane compound having an activating group include those containing a compound represented by the following general formula (VI).

[0047]

[Chemical 9] (In the formula, R⁷~ R^TenAre each independently a hydrogen atom,
Rogen, isocyanate group, hydroxyl group, chlorosilane
A functional group containing a ryl group, a functional group containing a dichlorosilyl group,
Contains functional group containing trichlorosilyl group, silanol group
Crosslinks by forming functional groups and siloxane bonds
Represents a silicon-containing functional group to be obtained, R¹¹And R ¹²Are each
Independently, hydrogen atom, halogen, isocyanate group and
It represents a hydroxyl group, and m is an integer of 1 or more. ) The silane compound having an activating group is chlorosilanated
It can be a compound.

The compound represented by the general formula (VI) is at least one compound selected from compounds represented by the following general formula (VII), general formula (VIII) and general formula (IX). Can be

[0049]

[Chemical 10] (In the formula, n is an integer of 1 or more.)

[0050]

[Chemical 11] (In the formula, n is an integer of 1 or more.)

[0051]

[Chemical 12] As the non-aqueous organic solvent, at least one organic solvent selected from a hydrocarbon organic solvent, a fluorine organic solvent and a chlorine organic solvent can be used.

The silica-based coating film forming solution may further contain an alkoxysilane compound.

Further, the alkoxysilane compound can be at least one compound selected from tetraethoxysilane and propyloxysilane.

The method for producing a solution for forming a silica-based coating film of the present invention, which corresponds to the above-mentioned second aspect, comprises dissolving a silane compound having an activating group in a dry atmosphere in a first non-aqueous organic solvent, 3 step of preparing a mixed solution, a step of preparing a 4th mixed solution by mixing water with a second non-aqueous organic solvent, and a step of reacting the silane compound having an activating group with water. Mixing the third mixed solution and the fourth mixed solution in a dry atmosphere, and using anhydrous silica fine particles dispersed in at least one of the third mixed solution and the fourth mixed solution. Is characterized by.

According to the above method, when the third mixed solution is prepared, the silane compound having an activating group is dissolved in a dry atmosphere, so that the activating group in the silane compound reacts with water. Can be prevented, and the reaction activity of the silane compound can be prevented from being impaired.

Since the third mixed solution and the fourth mixed solution are mixed in a dry atmosphere, the silane compound having an activating group reacts only with water contained in the fourth mixed solution. Furthermore,
Since anhydrous silica fine particles are dispersed in at least one of the third mixed solution and the fourth mixed solution, the activating group in the silane compound is a functional group having active hydrogen present on the surface of the anhydrous silica fine particles. react. Therefore, a compound in which a silane compound having an activating group is bonded to the anhydrous silica fine particles by a siloxane bond is generated. That is, it is possible to produce a silica-based film forming solution in which a silane compound having an activating group is bonded to anhydrous silica fine particles and in which such a compound is dispersed. Further, the solution for forming a silica-based coating film prepared as described above is a solution whose viscosity can be controlled by appropriately changing the addition amount of anhydrous silica fine particles as necessary, and also has a coating property. Are better. In addition, since the compound formed by binding the silane compound to the anhydrous silica fine particles contains many activating groups, a silica-based compound having excellent reactivity with a substrate having a functional group having active hydrogen is present. It is possible to produce a film-forming solution.

In the method for producing the silica-based coating forming solution, titanium oxide fine particles can be used instead of the anhydrous silica fine particles.

The molar ratio of the water to the silane compound having an activating group is preferably equimolar or less.

A chlorosilane compound can be used as the silane compound having an activating group.

The chlorosilane compound may be at least one compound selected from tetrachlorosilane, trichlorosilane, dichlorosilane, hexachlorodisiloxane and octachlorotrisiloxane.

As the first non-aqueous organic solvent and the second non-aqueous organic solvent, at least one organic solvent selected from a hydrocarbon organic solvent, a fluorine organic solvent and a chlorine organic solvent can be used.

The silica-based coating of the present invention corresponding to the second aspect is a silica-based coating formed on the surface of a substrate through a siloxane bond, and the silica-based coating contains anhydrous silica fine particles, The anhydrous silica fine particles are bonded to the silica-based coating and the base material through a siloxane bond, and the silica-based coating has a chemical structure containing no hydrocarbon group.

According to the above constitution, the silica-based coating is formed by forming a siloxane bond with the surface of the base material and the anhydrous silica fine particles, and therefore has excellent adhesion to the base material. Further, in the conventional sol-gel method using, for example, an alkoxysilane compound as a raw material, a silica-based coating film composed of molecules having side chains such as hydrocarbon groups (specifically, for example, methyl groups) was formed. However, the silica-based coating according to the present invention does not include impurities such as hydrocarbon groups in its chemical structure. Therefore, it is extremely high in purity and excellent in hardness and transparency.

The silica-based coating may contain titanium oxide fine particles instead of the anhydrous silica fine particles.

Further, the silica-based coating can be configured to include a repeating structural unit represented by the following structural formula (V).

[0066]

[Chemical 13] As a result, the film structure of the silica-based coating can be made to have a mesh structure, and can be made excellent in abrasion resistance and scratch resistance.

The above-mentioned base material can be a base material having a functional group having active hydrogen on its surface and having a heat resistance of the base material of 150 ° C. or less. Here, "heat resistance is 150
The temperature range of 15 ° C. or lower ”means that the temperature range in which the physical shape of the substrate and its chemical properties are not changed by the heat treatment is 15
It means 0 ° C. or lower.

The method for producing a silica-based coating film corresponding to the second aspect is a coating step of coating the surface of the substrate with the above-mentioned solution for forming a silica-based coating film in a dry atmosphere, and evaporating the non-aqueous organic solvent. A drying step of forming a siloxane compound coating having an activating group, and a silica-based coating forming step of contacting the siloxane compound coating with water molecules to form a silica-based coating containing anhydrous silica fine particles on the surface of the base material. The configuration includes and.

According to the above method, since the compound formed by binding the silane compound having an activating group to the anhydrous silica fine particles is dispersed in the solution for forming a silica-based coating film, the addition amount of the anhydrous silica fine particles is appropriately adjusted. If the viscosity is controlled by changing it, it is possible to apply the silica-based coating film forming solution thickly without causing dripping when applied to the surface of the substrate. As a result, even when it is desired to form a thick silica-based coating, there is no need to perform the catalyst addition and heat treatment steps that have been performed in the conventional sol-gel method, and it is possible to form a silica-based coating extremely easily. it can.

The silica-based film forming step can be performed in an atmosphere containing water.

Furthermore, after the above silica-based coating forming step, a heat treatment step of heating at a temperature of 100 ° C. or higher can be performed.

(3) Other aspects of the present invention include the following.

That is, when the silica-based coating film forming solution according to the first and second aspects is used as an adhesive composition, the silica-based coating film forming solution may be used in a dry atmosphere as the bonding method. A coating step of coating the surface of the object, a bonding step of bonding the object and another object through the silica-based coating forming solution applied to the surface of the object, and evaporating the non-aqueous organic solvent. Then, a drying step for forming a chlorosiloxane oligomer coating, and a silica for contacting the chlorosiloxane oligomer coating with water molecules to form a silica-based coating on the surface of the substrate, thereby adhering the object to another object. It can be configured to include a system film forming step.

According to the above method, the silica coating film is chemically adsorbed on the bonding surface between the object and another object, and can be used as an adhesive composition.

Furthermore, the silica-based coating forming solution according to the first and second aspects is used as an adhesive composition, and an adhesive structure as a result of adhering an arbitrary object and another object The body has a structure in which an object and another object are bonded to each other via a silica coating.

It is also possible to add the silica-based coating film forming solutions according to the first and second aspects to the coating composition.

The silica-based coating formed by using the solution for forming a silica-based coating is excellent in transparency and therefore can be used as a coating (varnish) for forming a particularly glossy transparent coating.

Further, it can be used in a paint for forming a colored coating film by adding any one selected from the group consisting of pigments, dyes and pigments to the above-mentioned paint composition.

Further, the silica-based coating film corresponding to the first and second aspects can be used as a passivation film for semiconductor devices.

On the other hand, the silica-based coating film corresponding to the first and second embodiments can be used as a passivation film for a thin film transistor array.

[0081]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) Embodiment 1
Corresponds to the first aspect of the invention. The first embodiment will be described below with reference to FIGS. 1 and 2. However, parts unnecessary for description are omitted, and there are parts illustrated in an enlarged or reduced form for ease of description.

First, the solution for forming a silica film according to the present invention will be described in detail. The silica-based film forming solution,
It is configured to include at least an organic solvent and a siloxane compound having an activating group.

The siloxane compound having an activating group includes a compound represented by the following general formula (I).

[0084]

[Chemical 14] (In the formula, R ^{1 to} R ⁴ may be independently crosslinked by forming a hydrogen atom, a halogen, an isocyanate group, a hydroxyl group, a chlorosilyl group, a dichlorosilyl group, a trichlorosilyl group, a silanol group and a siloxane bond. Represents a silicon-containing functional group, R ⁵ and R ⁶ independently represent a hydrogen atom, a halogen, an isocyanate group and a hydroxyl group, and m is an integer of 1 or more.) Here, the activating group is included. The siloxane compound is not limited to a chain compound such as a linear structure or a branched structure, and may be a cyclic compound. Further, in the compound represented by the general formula (I), m is an integer of 1 or more, but it is preferable that m has a degree of polymerization of a ligomer within the range of 2 to 1000, and further m Is 4 ~
More preferably, it is within the range of 100. m is 100
When a siloxane compound having a degree of polymerization higher than 0 and having a higher degree of polymerization than an oligomer is contained in the solution for forming a silica-based coating film, the viscosity of the solution for forming a silica-based coating film itself becomes large and the handleability is deteriorated, which is preferable. Absent.

Specific examples of the siloxane compound having an activating group include a chlorosiloxane compound, and examples of the chlorosiloxane compound include a chlorosiloxane oligomer.

The above chlorosiloxane oligomer is specifically, for example, a single compound or a combination of two or more compounds selected from compounds represented by the following general formula (II), general formula (III) and general formula (IV). May be included.

[0087]

[Chemical 15] (In the formula, n is an integer of 1 or more.)

[0088]

[Chemical 16] (In the formula, n is an integer of 1 or more.)

[0089]

[Chemical 17] (In the formula, n is an integer of 1 or more.) In the case of the chlorosiloxane oligomers represented by the general formulas (II) to (IV), n is an integer of 1 or more, but n is 2 or more. The degree of polymerization is preferably such that the degree of oligomer is in the range of 1000, and more preferably n is in the range of 4 to 100. As the organic solvent, a non-aqueous organic solvent can be used, and as the non-aqueous organic solvent, a single organic solvent selected from hydrocarbon-based organic solvents, fluorine-based organic solvents, and chlorine-based organic solvents, or 2 Those that include more than one type can be used. The hydrocarbon-based organic solvent is not particularly limited, and specific examples thereof include n-hexane, toluene, cyclohexane, isooctane, dimethyl silicon and the like. Further, the above-mentioned fluorine-based organic solvent is not particularly limited, and examples thereof include perfluorooctane.
Furthermore, the chlorine-based organic solvent is not particularly limited, and examples thereof include chloroform. By using these non-aqueous organic solvents, it is possible to easily remove water in the non-aqueous organic solvent. Further, since it absorbs little water as a solvent, it prevents the activated group in the siloxane compound, for example, the chlorosilyl group in the chlorosiloxane oligomer, from dehydrochlorinating with excess water. This makes it possible to prepare a highly reactive silica-based film-forming solution containing a large amount of chlorosilyl groups as activating groups. Further, the boiling point of the non-aqueous organic solvent according to the present invention is lower than the boiling point of the organic solvent used in the conventional silica film forming solution. Therefore, it is possible to evaporate the non-aqueous organic solvent at room temperature without performing heat treatment. Therefore, it is possible to provide a solution for forming a silica-based film having excellent handleability.

Next, the method for producing the silica film forming solution according to the present invention will be described in detail. First, a solution A in which a chlorosilane compound as a silane compound having an activating group is mixed and dissolved in a first non-aqueous organic solvent (first organic solvent)
(First mixed solution) is prepared. The solution A is prepared in a dry atmosphere such that the relative humidity is within the range of 35% or less, for example, dry air, dry nitrogen or dry helium. This is because when the relative humidity exceeds 35%, the moisture in the atmosphere and the chlorosilyl group in the chlorosilane compound excessively react with each other, which causes a disadvantage that the prepared solution becomes cloudy. Examples of the chlorosilane compound include tetrachlorosilane (SiC
l ₄ ), trichlorosilane (SiHCl ₃ ), dichlorosilane (SiH ₂ Cl ₂ ), hexachlorodisiloxane (S
iCl ₃ —O—SiCl ₃ ), octachlorotrisiloxane (Cl (SiCl ₂ O) ₂ SiCl ₃ ) and the like. By using at least one compound selected from these compound groups, it is convenient to obtain a silica-based coating film that does not contain impurities such as hydrocarbon groups. The first
The concentration of the chlorosilane compound dissolved in the non-aqueous organic solvent is preferably in the range of 0.01 M / l to 10 M / l. If it is less than 0.01 M / l, there is a disadvantage that the effect of forming the silica-based coating is small. On the other hand, when it is more than 10 M / l, there is a disadvantage that it becomes difficult to apply the solution uniformly when using the solution for forming a silica-based film.

On the other hand, a solution B (second mixed solution) is prepared by mixing and dissolving water as an oligomerizing agent in a second non-aqueous organic solvent (second organic solvent) until it becomes saturated. Here, when water is used as the oligomerizing agent, it is preferable that particles are removed by filtration or the like. This is because if impurities such as particles are contained in water, they may be incorporated into the silica-based coating and impair the uniformity of the silica-based coating. Further, the oligomerizing agent is not limited to the above-mentioned water, and any substance having a divalent active hydrogen can be used. Specific examples include amines such as methylamine and ethanolamine, ammonia, and the like.

The first and second non-aqueous organic solvents are
It goes without saying that it is contained in the non-aqueous organic solvent described above. This is because these first and second non-aqueous organic solvents are combined to form a non-aqueous organic solvent. Therefore, the above-mentioned various organic solvents can be adopted as the first and second non-aqueous organic solvents. Further, among the organic solvents exemplified above, the first non-aqueous organic solvent is preferably a non-aqueous non-polar solvent, and the second non-aqueous organic solvent is preferably a non-aqueous polar solvent from the viewpoint of dissolving water.

Next, the solution A and the solution B are mixed in a dry atmosphere and left standing for a predetermined time. As a result, a dehydrochlorination reaction occurs between the chlorosilane compound and water, and a silica-based film-forming solution containing the chlorosiloxane oligomer represented by the general formula (I) is obtained. Here, the above solution A
And the mixing ratio of the solution B are set so that the molar ratio of the water to the chlorosilane compound is equal to or less than equimolar. As a result, the chlorosilyl group as an activating group in the chlorosilane compound is converted into the hydroxyl group (—O in the water molecule).
Even if the dehydrochlorination reaction with H) is performed, since the number of chlorosilyl groups is larger than that of the above hydroxyl groups, it is possible to prevent all chlorosilyl groups from reacting. This prevents the activity of the silica-based film-forming solution itself from deteriorating due to a decrease in residual chlorosilyl groups in the prepared silica-based film-forming solution and a decrease in reaction activity. Because of that.

The reason why the solution A and the solution B are mixed in a dry atmosphere as described above is as follows.
That is, for example, when the solution A and the solution B are mixed in an atmosphere having a relative humidity of more than 35%, the mixed solution becomes cloudy. This indicates that the water contained in the atmosphere and the chlorosilyl group in the chlorosilane compound caused a dehydrochlorination reaction to reduce the reaction activity of the chlorosilane compound. As a result, the chlorosilyl group as an activating group is reduced in the same manner as described above, and the activity of the silica film forming solution itself is deteriorated. Therefore, it is necessary to mix the solution A and the solution B in a dry atmosphere having a relative humidity of 35% or less.

Next, the silica coating according to the present invention will be described in detail. The silica-based coating film of the present invention is a coating film having a network structure in which the siloxane compound having a plurality of activating groups, which is its constituent unit, is chemically adsorbed on the surface of the substrate.

More specifically, it is as follows. That is, as shown in FIG. 2, the silica-based coating 13 is formed on the surface of the base material 11 via a siloxane bond (—SiO—). In addition, a plurality of polysiloxane oligomers are physically entangled with each other, and like a repeating structural unit represented by the following structural formula (V), have a network structure in which they are strongly bonded by a chemical cross-linking bond.

[0097]

[Chemical 18] Therefore, the silica-based coating 13 according to the present invention has excellent wear resistance and scratch resistance. Furthermore, as is clear from FIG.
The silica-based coating 13 does not contain impurities such as hydrocarbon groups. This is because a chlorosilane compound having no hydrocarbon group or the like is used as a raw material of the silica-based coating 13, and no catalyst or the like is added.
As described above, since the silica-based coating 13 does not contain a hydrocarbon group or the like, the silica-based coating has an extremely high purity and is excellent in hardness and transparency. When such a high-purity silica coating 13 is used as a base film for the base material 11, it also exhibits an excellent blocking function against impurity ions and the like. Furthermore, a hydroxyl group (—OH) is introduced mainly in the surface portion of the silica-based coating film 13 to form a hydrophilic coating film. Accordingly, when it is used for a liquid crystal display device or the like, for example, it can be used as a base layer of an alignment film.

The base material 11 is not particularly limited, and for example, a base material having a functional group having active hydrogen such as a hydroxyl group (—OH) or an imino group (> NH) on the surface can be used. is there. In particular, the present invention is also effective for a substrate having a heat resistance temperature of 150 ° C. or lower (the reason for this will be described when explaining the method for producing a silica-based coating). Specific examples include those made of materials such as glass, plastic, ceramics, metal, fiber, leather, and paper. When the silica-based coating 13 of the present invention is formed on the surface of the base material made of glass, it is possible to prevent the alkali from being eluted from the glass. In the case of ceramics or metals, the silica-based coating film functions as a protective film and can improve the acid resistance of the substrate by making it difficult to react with chemicals and the like. Further, in the case of fibers, leather and paper, the hydrophilicity of the surface of the base material can be improved.
For example, when the present invention is applied to nylon or stockings, the touch can be improved. When applied to a wig, it also exhibits an antistatic effect.

On the other hand, when the base material 11 is made of a material having no functional group having active hydrogen, or when it is made of a material originally having few functional groups, the following treatment is performed. It becomes possible to apply to the present invention. That is, the functional group having active hydrogen may be introduced into the surface of the base material by subjecting the surface of the base material to corona treatment in air or oxygen plasma treatment. This allows the dehydrochlorination reaction with the chlorosilyl group. Specific examples of the above-mentioned base material include water-repellent plastics such as acrylic plates and polycarbonate plates.

Next, the method for producing the silica coating according to the present invention will be described in detail. In the following, for convenience of explanation, the case where a chlorosiloxane oligomer is used as the siloxane compound having an activating group in the solution for forming a silica-based coating film is described as an example. It goes without saying that even if the group is a siloxane compound, it can be produced by the same method.

The silica-based coating 13 is obtained by contacting the surface of the substrate 11 with the solution for forming a silica-based coating in a dry atmosphere and further reacting with water.

More specifically, a substrate 11 degreased by thoroughly washing in advance is prepared, and the substrate 1 is dried in a dry atmosphere.
1 is coated with a solution for forming a silica-based film to form a coating film (coating step). As a result, the chlorosilyl group in the chlorosiloxane oligomer in the silica-based film forming solution causes a dehydrochlorination reaction with the -OH group present on the surface of the base material 11 and a functional group having active hydrogen such as> NH group. And forms a covalent bond (siloxane bond) with the surface of the substrate 11. Here, the method for applying the solution for forming a silica-based film is not particularly limited, and a conventionally known method can be used. Specific examples thereof include a spinner method, a roll coater method, a dipping and lifting method, a spray method, a screen printing method, and a brush coating method. The degreasing is performed to improve the adhesion performance of the solution for forming a silica-based coating film on the surface of the substrate 11, and the surface treatment may be performed by a conventionally known method.

Next, the non-aqueous organic solvent in the coating film is evaporated by leaving the coated base material 11 at room temperature (drying step). As a result, the chlorosiloxane oligomer coating film 12 shown in FIG. 1 is formed. The chlorosilane compound is present in the coating film as a chlorosiloxane oligomer and does not evaporate together with the non-aqueous organic solvent.

Then, the base material 11 on which the chlorosiloxane oligomer coating film 12 is formed is taken out into an atmosphere containing water (silica coating film forming step). As a result, the remaining chlorosilyl group immediately undergoes a dehydrochlorination reaction with water. As a result, a crosslinked structure is formed in the film, hydroxyl groups are introduced into the film surface, and the silica-based coating film 13 according to the present invention is formed (see FIG. 2). The method of bringing the chlorosiloxane oligomer coating film 12 into contact with water is not particularly limited, but it is preferably performed in an atmosphere containing water as described above. For example, when immersed in water, the residual chlorosilyl groups in the chlorosiloxane oligomer coating 12 suddenly undergo a dehydrochlorination reaction with water and become cloudy. As a result, the silica-based coating 13 cannot be formed on the surface of the base material 11, so dipping in water is not preferable.

Further, a heat treatment step may be performed after the above silica-based film forming step to remove water. As a result, the hydroxyl group is removed, and the silica-based coating film 13 having a higher density and excellent denseness can be obtained. The heating temperature in the heat treatment step may be such that water can be sufficiently evaporated within the allowable range of heat resistance of the base material 11. The heating temperature is 100, which is the boiling temperature of water.
℃ or more is preferable, and 1 to reduce the heat treatment time.
It is more preferably 20 ° C. or higher.

In the method for producing the silica-based coating film 13 of the present invention, it is also possible to add an alkoxysilane compound to the silica-based coating film forming solution in advance. In the conventional method for producing a silica-based coating, it is necessary to add an acid catalyst together with the alkoxysilane compound, but in the present invention, it is not necessary to add an acid catalyst. This is because hydrochloric acid is generated by the dehydrochlorination reaction between the chlorosilyl group and the hydroxyl group in the chlorosiloxane oligomer. Since this hydrochloric acid serves as an acid catalyst, a dealcoholization reaction represented by the following chemical reaction formula (X) occurs. As a result, a hydroxyl group is introduced into the alkoxysilane compound.

[0107]

[Chemical 19] Here, when the heat treatment step is performed, the following chemical reaction formula (X
The dehydration reaction shown in I) occurs, and a silica-based coating film having a higher density and excellent denseness can be obtained.

[0108]

[Chemical 20] The alkoxysilane compound is not particularly limited, and specific examples thereof include tetraethoxysilane and propyloxysilane.

If the concentration of the silica coating film forming solution is diluted or concentrated before use, the thickness of the silica coating film can be controlled. As a result, the silica-based coating can be formed to have a desired film thickness. The diluting solvent used for diluting is not particularly limited,
The organic solvents mentioned above can be used.

From the above, according to the method for producing a silica-based coating film according to the first embodiment, the addition of a catalyst and the heat treatment step, which have been carried out in the conventional production method, are not necessary. A coating can be formed. Further, a silica-based coating can be formed on the surface of a base material made of a material having low heat resistance.

In the above description, the first aspect of the present invention has been described according to the most preferred embodiment.
The present invention can be suitably used for all those for which a silica-based coating has been used conventionally. For example, in a semiconductor device, it can be used as an interlayer insulating film or a passivation film. In a liquid crystal device, it can be used as a flattening film between a transparent substrate and a transparent electrode, or as a base layer of the alignment film between the transparent electrode and the alignment film. Furthermore, the present invention is not limited to these applications and can be applied to a base material having low heat resistance. For example, it can be used as a hard coat film for spectacle lenses having low heat resistance. (Embodiment 2) Embodiment 2 corresponds to the second aspect of the present invention.

First, the silica-based coating film forming solution according to the second embodiment will be described in detail. The solution for forming a silica-based film contains a non-aqueous organic solvent and a compound in which a silane compound having an activating group is bonded to anhydrous silica fine particles or titanium oxide fine particles.

The above anhydrous silica fine particles are several nm to several hundreds n.
Silica fine particles having an average particle diameter of about m and no adsorbed water on the particle surface. On the other hand, a functional group having active hydrogen (for example, —OH group) is present on the surface of the particle and can react with an activating group such as a chlorosilyl group. Examples of the anhydrous silica fine particles include Aerosil 200 and Aerosil 30 manufactured by Nippon Aerosil Co., Ltd.
0 etc. are mentioned.

Further, the titanium oxide fine particles also have an average particle diameter of several nm to several hundreds nm, similar to the above anhydrous silica fine particles, there is no adsorbed water on the particle surface, and a functional group having active hydrogen is present. Existing. As the titanium oxide fine particles,
Examples include P25 manufactured by Nippon Aerosil Co., Ltd.

By adding the above-mentioned anhydrous silica fine particles or titanium oxide to the silica-based coating forming solution, the viscosity of the silica-based coating forming solution can be controlled and the coating property can be improved. Specifically, the viscosity can be controlled by appropriately changing the addition amount of anhydrous silica fine particles or the like and the amount of the non-aqueous organic solvent as needed. The mixed concentration of the anhydrous silica fine particles with respect to the solution for forming a silica-based coating film is preferably in the range of about 0.01 to 20% by weight, and preferably 0.1 to 10% by weight in terms of viscosity and coating. It is more preferable in terms of film property. If the mixing concentration exceeds 20% by weight, the viscosity of the silica-based coating film forming solution becomes too high and the handleability is deteriorated, which is not preferable. on the other hand,
If the mixing concentration is less than 0.01% by weight, various effects due to the addition of anhydrous silica fine particles are small, and, for example, the controllability of the viscosity is reduced, or it is difficult to form a thick silica-based film. Is not preferable.

The silane compound having an activating group is represented by the following general formula (VI).

[0117]

[Chemical 21] (In the formula, R⁷~ R^TenAre each independently a hydrogen atom,
Rogen, isocyanate group, hydroxyl group, chlorosilane
A functional group containing a ryl group, a functional group containing a dichlorosilyl group,
Contains functional group containing trichlorosilyl group, silanol group
Crosslinks by forming functional groups and siloxane bonds
Represents a silicon-containing functional group to be obtained, R¹¹And R ¹²Are each
Independently, hydrogen atom, halogen, isocyanate group and
It represents a hydroxyl group, and m is an integer of 1 or more. ) Here, as the silane compound having an activating group,
Limited to chain compounds such as straight-chain and branched structures
It may be a cyclic compound instead of one. In addition, the general formula (V
Although m shown in I) is an integer of 1 or more, m is 2 to
The degree of polymerization is about that of an oligomer within the range of 1,000.
Preferably, m is in the range of 4-100.
Is more preferable. High degree of polymerization with m exceeding 1000
Fluorine silane compound is contained in the solution for forming silica-based film.
If so, the viscosity of the silica-based film-forming solution itself becomes large.
And the handleability is reduced.

Further, the silane compound having an activating group represented by the above general formula (VI) is specifically represented by the following general formula (VII), general formula (VIII) and general formula (IX). It may contain one kind or two or more kinds of compounds selected from the compounds shown.

[0119]

[Chemical formula 22] (In the formula, n is an integer of 1 or more.)

[0120]

[Chemical formula 23] (In the formula, n is an integer of 1 or more.)

[0121]

[Chemical formula 24] (In the formula, n is an integer of 1 or more.) In the general formulas (VII) to (IX), n is an integer of 1 or more, and n is an oligomer in the range of 2 to 1000. The degree of polymerization is preferably n, and n is 4
More preferably, it is within the range of -100.

Here, the anhydrous silica fine particles and the silane compound having an activating group are as described above, but in the solution for forming a silica-based film according to the present invention, these are combined to form a solution. Dispersed throughout. That is, for example, as shown in the following chemical formula (XII), the hydroxyl group present on the surface of the anhydrous silica fine particles and the activating group in the silane compound react to form a siloxane bond.

[0123]

[Chemical 25] (In the formula, R⁷~ R^TenAre each independently a hydrogen atom,
Rogen, isocyanate group, hydroxyl group, chlorosilane
A functional group containing a ryl group, a functional group containing a dichlorosilyl group,
Contains functional group containing trichlorosilyl group, silanol group
Crosslinks by forming functional groups and siloxane bonds
Represents a silicon-containing functional group to be obtained, R¹¹And R ¹²Are each
Independently, hydrogen atom, halogen, isocyanate group and
It represents a hydroxyl group, and m is an integer of 1 or more. ) Also, the mode of bonding between the anhydrous silica fine particles and the silane compound
Is not limited to those exemplified above, but is shown in chemical formula (VI).
You R⁷~ R¹²Be connected at least one place
Good.

Further, when the silane compound having an activating group is a chlorosilane compound represented by any of the above general formulas (VII) to (IX), the bond with the anhydrous silica fine particles is the same as that of the SiCl group in each chlorosilane compound. The OH groups in the silica particles are dehydrochlorinated to form a siloxane bond.
The siloxane-bonded site may be bonded at least at one of the sites of the chlorosilane compound to which the SiCl group is added.

As the non-aqueous organic solvent, an organic solvent selected from a hydrocarbon organic solvent, a fluorine organic solvent and a chlorine organic solvent may be used alone or in combination with two or more. The hydrocarbon-based organic solvent is not particularly limited, and specific examples thereof include n-hexane, toluene, cyclohexane, isooctane, dimethyl silicon and the like. Further, the above-mentioned fluorine-based organic solvent is not particularly limited, and examples thereof include perfluorooctane. Furthermore, the chlorine-based organic solvent is not particularly limited, and examples thereof include chloroform. By using these non-aqueous organic solvents,
There is an advantage that water can be easily removed also in the non-aqueous organic solvent. Furthermore, since the absorption of water as a solvent is small, the activating group in the silane compound is prevented from reacting with excess water. As a result, a silica-based coating film forming solution containing a large number of activating groups, having excellent coating properties and high reactivity can be prepared. Further, the boiling point of the non-aqueous organic solvent according to the present invention is lower than the boiling point of the organic solvent used in the conventional silica film forming solution. Therefore, it is possible to evaporate the non-aqueous organic solvent at room temperature without performing heat treatment. Therefore, it is possible to provide a solution for forming a silica-based film having excellent handleability.

Next, the method for producing the silica film forming solution according to the second embodiment will be described in detail. First, a silane compound having an activating group and anhydrous silica fine particles are mixed with a first non-aqueous organic solvent to prepare a solution C (third mixed solution).

At this time, in the solution C, the silane compound having an activating group and the anhydrous silica fine particles are bound by a siloxane bond. However, the amount of the anhydrous silica fine particles added is set so that the viscosity of the solution for forming a silica-based coating film after completion has a desired value. The solution C is prepared in a dry atmosphere such that the relative humidity is within the range of 35% or less, for example, dry air, dry nitrogen or dry helium. This is because when the relative humidity exceeds 35%, the moisture in the atmosphere and the activated groups in the silane compound excessively react with each other, which causes a disadvantage that the produced solution becomes cloudy. A chlorosilane compound etc. are mentioned as a silane compound which has the said activation group. Further, examples of the chlorosilane compound include tetrachlorosilane (SiCl ₄ ) and trichlorosilane (SiHC
l ₃ ), dichlorosilane (SiH ₂ Cl ₂ ), hexachlorodisiloxane (ClSiCl ₂ OSiCl ₃ ), octachlorotrisiloxane (Cl (SiCl ₂ O) ₂ SiCl
₃ ) etc. By using at least one compound selected from these compound groups, it is convenient to obtain a silica-based coating film that does not contain impurities such as hydrocarbon groups. The concentration of the silane compound having an activating group, which is dissolved in the first non-aqueous organic solvent, is 0.01 M /
It is preferably in the range of 1 to 10 M / l. 0.0
If it is less than 1 M / l, there is a disadvantage that the effect of forming the silica-based coating, that is, various effects imparted to the substrate by forming the silica-based coating is low. On the other hand, 10M / l
If it is larger than the above range, it is difficult to apply the solution uniformly when using the solution for forming a silica-based film.

On the other hand, a solution D (fourth mixed solution) is prepared by mixing and dissolving water in the second non-aqueous organic solvent until it becomes saturated. Here, the water is preferably water from which particles have been removed by filtration or the like. This is because if impurities such as particles are contained in water, they may be incorporated into the silica-based coating and impair the uniformity of the silica-based coating.

The first and second non-aqueous organic solvents are
It goes without saying that it is contained in the non-aqueous organic solvent described above. This is because these first and second non-aqueous organic solvents are combined to form a non-aqueous organic solvent. Therefore, the above-mentioned various organic solvents can be adopted as the first and second non-aqueous organic solvents. Further, among the organic solvents exemplified above, the first non-aqueous organic solvent is preferably a non-aqueous non-polar solvent, and the second non-aqueous organic solvent is preferably a non-aqueous polar solvent from the viewpoint of dissolving water.

Next, the solution C and the solution D are mixed in a dry atmosphere and left standing for a predetermined time. As a result, the silane compound having an activating group bonded to the anhydrous silica fine particles and water undergo a dehydrochlorination reaction to obtain a silica-based film forming solution in which the compound represented by the general formula (XII) is dispersed. Here, the mixing ratio of the solution C and the solution D is set so that the molar ratio of the water to the silane compound having an activating group is equal to or less than equimolar. As a result, even if the activating group in the silane compound reacts with the hydroxyl group (—OH) in the water molecule, the number of activating groups is larger than that of the hydroxyl group, and therefore all the activating groups are It can be suppressed so as not to react. This prevents the activity of the silica-based film-forming solution itself from deteriorating due to a decrease in residual activating groups in the prepared silica-based film-forming solution and a decrease in reaction activity. To do so.

The reason why the solution C and the solution D are mixed in a dry atmosphere as described above is as follows.
That is, for example, when the solution C and the solution D are mixed in an atmosphere having a relative humidity of more than 35%, the mixed solution becomes cloudy. This indicates that the water contained in the atmosphere and the activating group in the silane compound caused a dehydrochlorination reaction to reduce the reaction activity of the silane compound having the activating group. As a result, the number of activating groups decreases as described above, and the activity of the silica-based film forming solution itself deteriorates. Therefore, it is necessary to mix the solution C and the solution D in a dry atmosphere having a relative humidity of 35% or less.

In the method for producing the solution for forming a silica-based film, the case where anhydrous silica fine particles are added to the solution C has been described, but the present invention is not limited to this. It may be added to the solution D. Alternatively, it may be added to both solution C and solution D.

Next, the silica-based coating film according to the second embodiment will be described in detail. The silica-based coating film of the present invention is a coating film having a network structure in which the polysiloxane oligomer, which is its constituent unit, is chemically adsorbed on the surface of the substrate and the anhydrous silica fine particles.

The details are as follows. That is,
As shown in FIG. 4, the plurality of polysiloxane oligomers constituting the silica-based coating film 24 are physically entangled with each other and chemically bridged like a repeating structural unit represented by the following structural formula (V). It has a network structure in which it is strongly bonded by the cross-linking.

[0135]

[Chemical formula 26] Further, the above polysiloxane oligomer has a siloxane bond (--SiO 2) on the surface of the base material 21 and the anhydrous silica fine particles 23.
-) Is formed. Further, as is clear from FIG. 4, the anhydrous silica fine particles 23 are contained in a state of being siloxane-bonded to the substrate 21. Therefore, the silica coating 24 according to the present invention is excellent in wear resistance and scratch resistance. Moreover, the silica-based coating film 24 does not contain a polysiloxane oligomer having a hydrocarbon group or the like. This is because the silane compound having no hydrocarbon group and the anhydrous silica fine particles are used as the raw material of the silica-based coating 4, and no catalyst or the like is added.

As described above, since the silica-based coating 24 does not contain a hydrocarbon group or the like, the silica-based coating 24 has extremely high purity and excellent hardness and transparency. When such a high-purity silica-based coating film 24 is used as a base film of the base material 21, it also exhibits an excellent blocking function against impurity ions and the like. Further, a hydroxyl group (-OH) is introduced mainly in the surface portion of the silica-based coating film 24, and the coating film is hydrophilic. Accordingly, when it is used for a liquid crystal display device or the like, for example, it can be used as a base layer of an alignment film.

The base material 21 is not particularly limited, and for example, a polymer base material having a functional group having active hydrogen such as hydroxyl group (-OH) or imino group (> NH) on the surface is used. It is possible. In particular, the present invention is also effective for a substrate having a heat resistance temperature of 150 ° C. or lower (the reason for this will be described when explaining the method for producing a silica-based coating). Specific examples include materials made of materials such as glass, ceramics, plastics, metals, fibers, leather, and paper. When the silica-based coating film 24 of the present invention is formed on the surface of the base material made of glass, it is possible to prevent alkali from being eluted from the glass. In the case of ceramics or metals, the silica-based coating film functions as a protective film and can improve the acid resistance of the substrate by making it difficult to react with chemicals and the like. Further, in the case of fibers, leather and paper, the hydrophilicity of the surface of the base material can be improved. For example, when the present invention is applied to nylon or stockings, the touch can be improved.
When applied to a wig, it also exhibits an antistatic effect.

On the other hand, when the base material 21 is made of a material having no functional group having active hydrogen, or when it is made of a material originally having a small number of these functional groups, the following treatment is performed. It becomes possible to apply to the present invention. That is, the functional group having active hydrogen may be introduced into the surface of the base material by subjecting the surface of the base material to corona treatment in air or oxygen plasma treatment. This allows the dehydrochlorination reaction with the chlorosilyl group. Specific examples of the above-mentioned base material include water-repellent plastics such as acrylic plates and polycarbonate plates.

Next, the method for producing the silica film forming solution according to the present invention will be described in detail. In the following,
For convenience of explanation, the case where a chlorosiloxane oligomer is used as the silane compound having an activating group in the solution for forming a silica-based film is described as an example. Needless to say, it can be manufactured by the same method.

The silica-based coating film 24 is obtained by contacting the surface of the base material 21 with the silica-based coating film forming solution in a dry atmosphere and further reacting with water.

More specifically, a substrate 21 degreased by thoroughly washing it in advance is prepared, and the substrate 2 is dried in a dry atmosphere.
1 is coated with a solution for forming a silica-based film to form a coating film (coating step). As a result, the chlorosilyl group in the chlorosiloxane oligomer in the silica-based film forming solution causes a dehydrochlorination reaction with the -OH group present on the surface of the base material 21 and a functional group having active hydrogen such as> NH group. Then, it is covalently bonded (siloxane bond) to the surface of the substrate 21 while containing the anhydrous silica fine particles 23. Here, the method for applying the solution for forming a silica-based film is not particularly limited, and a conventionally known method can be used. Specific examples thereof include a spinner method, a roll coater method, a dipping and lifting method, a spray method, a screen printing method, and a brush coating method. In particular, the addition of the anhydrous silica fine particles 23 facilitates the adjustment of the viscosity of the solution for forming a silica-based film and improves the coating property.

For reference, the viscosity of the silica film-forming solution is preferably several thousand to tens of thousands (cps). The above degreasing is performed to improve the adhesion performance of the solution for forming a silica-based coating film to the surface of the substrate 21, and the surface treatment may be performed by any other conventionally known method.

Next, the coated base material 21 is left at room temperature to evaporate the non-aqueous organic solvent in the coating film (drying step). As a result, the chlorosiloxane oligomer coating film 22 shown in FIG. 3 is formed. The silane compound having an activating group is present as a chlorosiloxane oligomer in the coating film and does not evaporate together with the non-aqueous organic solvent.

Subsequently, the base material 21 on which the chlorosiloxane oligomer coating film 22 is formed is taken out into an atmosphere containing water (silica coating film forming step). As a result, the remaining chlorosilyl group immediately undergoes a dehydrochlorination reaction with water. As a result, a crosslinked structure is formed in the film, hydroxyl groups are introduced into the film surface, and the silica-based coating film 24 according to the present invention is formed (see FIG. 3). The method for bringing the chlorosiloxane oligomer coating film 22 into contact with water is not particularly limited, but it is preferably performed in an atmosphere containing water as described above. For example, when immersed in water, the residual chlorosilyl groups in the chlorosiloxane oligomer coating 22 suddenly undergo a dehydrochlorination reaction with water and become cloudy. As a result, the silica coating 23 cannot be formed on the surface of the base material 21, so it is not preferable to immerse it in water.

Further, the silica-based coating film forming step (FIG. 3)
After that, a heat treatment step may be performed to remove water.
Thereby, the hydroxyl group is removed, and the silica-based coating film 24 having a higher density and excellent denseness can be obtained.
The heating temperature in the heat treatment step may be such that water can be sufficiently evaporated within the allowable range of heat resistance of the base material 21. The heating temperature is preferably 100 ° C. or higher, which is the boiling temperature of water, and more preferably 120 ° C. or higher in order to shorten the heat treatment time.

In addition, in the method for producing the silica-based coating film 24 of the present invention, it is possible to add an alkoxysilane compound to the solution for forming the silica-based coating film in advance. In the conventional method for producing a silica-based coating, it is necessary to add an acid catalyst together with the alkoxysilane compound, but in the present invention, it is not necessary to add an acid catalyst. This is because hydrochloric acid is generated by the dehydrochlorination reaction between the chlorosilyl group and the hydroxyl group in the chlorosiloxane oligomer. Since this hydrochloric acid serves as an acid catalyst, a dealcoholization reaction represented by the following chemical reaction formula (X) occurs. As a result, a hydroxyl group is introduced into the alkoxysilane compound.

[0147]

[Chemical 27] Here, when the heat treatment step is performed, the following chemical reaction formula (X
The dehydration reaction shown in I) occurs, and a silica-based coating film having a higher density and excellent denseness can be obtained.

[0148]

[Chemical 28] The alkoxysilane compound is not particularly limited, and specific examples thereof include tetraethoxysilane and propyloxysilane. However, among the above-mentioned alkoxysilane compounds, tetramethoxysilane is highly toxic to the human body and therefore should be avoided.

If the concentration of the silica-based coating forming solution is diluted or concentrated before use, the thickness of the silica-based coating can be controlled. Furthermore, by adding anhydrous silica fine particles, the viscosity of the coating liquid can be adjusted and a silica-based coating film can be formed to have a desired film thickness. The diluting solvent used for diluting is not particularly limited, and the non-aqueous organic solvent described above can be used.

As described above, according to the method for manufacturing a silica-based coating film according to the second embodiment, the addition of a catalyst and the heat treatment step, which have been carried out in the conventional manufacturing method, are not required, and therefore, the thick film can be extremely easily prepared. It is possible to form a silica-based coating of
Furthermore, a silica-based coating can be formed on the surface of a base material made of a material having low heat resistance.

In the above description, the second aspect of the present invention is used.
Although the aspect has been described according to the most preferable embodiment, the present invention can be suitably used for all those in which a silica-based coating has been conventionally used. For example, in semiconductor devices,
It can be used as an interlayer insulating film or a passivation film. or,
In a liquid crystal device, it can be used as a flattening film between a transparent substrate and a transparent electrode, or can be used as a base layer of the alignment film between the transparent electrode and the alignment film. Further, it can be used as a passivation film for a TFT array. Furthermore, the present invention is not limited to these applications.
It is also applicable to a base material having low heat resistance. For example,
It can be used as a hard coat film for spectacle lenses with low heat resistance. (Other Matters) The solution for forming a silica film according to the present invention can also be used as an adhesive for adhering an object to another object. This is because, if the objects have a functional group having active hydrogen on the surface, they can be chemically adsorbed to form a silica-based coating in the gaps between them, resulting in the ability to bond the objects together. Because it does.

Therefore, the present invention also provides an adhesive structure in which an object and another object are adhered via the silica coating by using the solution for forming a silica coating as an adhesive. can do.

In particular, when the glass fibers are bonded to each other or the glass fibers are bonded to an object made of another material, the silica-based coating film forming solution of the present invention is useful as an adhesive.

The method of using the solution for forming a silica film according to the present invention as an adhesive is as follows.

First, two objects having functional groups having active hydrogen on their surfaces are prepared, and the silica-based film forming solution is applied to the surface of one of the objects in a dry atmosphere to form a coating film (coating step). ). As a result, the chlorosilyl group in the chlorosiloxane oligomer in the silica-based film-forming solution causes a dehydrochlorination reaction with the functional group having active hydrogen existing on the surface of the object to form a siloxane bond on the surface of the object. Next, in a dry atmosphere, the other object is pasted and adhered to the one object via the coating film (bonding step). As a result, a dehydrochlorination reaction is caused on the surface of the other object in the same manner as described above to cause chemical adsorption.

Next, the non-aqueous organic solvent in the coating film is evaporated by leaving the coating film in the gap between one object and the other object at room temperature (drying step). As a result, a chlorosiloxane oligomer coating film is formed.

Subsequently, the chlorosiloxane oligomer coating film is taken out in an atmosphere containing water (silica coating film forming step). As a result, the remaining chlorosilyl group immediately undergoes a dehydrochlorination reaction with water, and becomes a crosslinked structure in the film, so that the adhesive structure according to the present invention can be manufactured.

[0158]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the materials of the components described in this example, the processing conditions, and the like are not intended to limit the scope of the present invention to only those unless otherwise specified, and are merely illustrative examples. Nothing more than. (Example 1) This example 1 corresponds to the first aspect of the present invention and relates to the preparation of a silica-based coating film forming solution. More details are as follows.

First, in a dry atmosphere having a relative humidity of 5%, dimethyl silicon as a first non-aqueous organic solvent was added to tetrachlorosilane (SiC) as a chlorosilane compound.
l ₄ ) was mixed and dissolved to prepare a solution A (first mixed solution). The concentration of SiCl _{4 in} the solution A is 0.1 M / l
And Next, water was mixed and dissolved in chloroform as the second non-aqueous organic solvent until it was saturated, to prepare a solution B (second mixed solution).

Subsequently, the solution A and the solution B are treated with the S
iCl_FourHumidity of 5% so that the number of moles of water and water are the same.
Mix in a dry atmosphere and let stand overnight. At this time, Si
Cl _FourAnd water cause dehydrochlorination reaction, and chlorosiloxane
A silica-based film-forming solution containing an oligomer was obtained.

Qualitative analysis (liquid chromatography, infrared spectroscopy, etc.) of the silica-based coating film forming solution according to this example was conducted to find the following general formulas (II), (III) and (IV).
It was found that the substance represented by

[0162]

[Chemical 29] (In the formula, n is an integer of 1 or more.)

[0163]

[Chemical 30] (In the formula, n is an integer of 1 or more.)

[0164]

[Chemical 31] (In the formula, n is an integer of 1 or more.) (Example 2) In this example, a silica-based film was formed using the solution for forming a silica-based film prepared in Example 1 above.

First, the base material 11 made of glass was thoroughly degreased by thoroughly washing it. Next, the silica-based film-forming solution was added to the substrate 1 in a dry atmosphere with a humidity of 5%.
It was applied to one surface. Furthermore, dimethyl silicon and chloroform were evaporated at room temperature to form a chlorosiloxane oligomer coating 12 (see FIG. 1).

Subsequently, the base material 11 on which the chlorosiloxane oligomer coating film 12 was formed was exposed in an atmosphere containing water to react the water with the chlorosiloxane oligomer. As a result, the silica-based coating film 13 having a thickness of about 8 nm
Were formed (see FIG. 2). Here, it was confirmed by analysis that the silica-based coating 13 was configured to include a structural unit represented by the following chemical formula (XIII).

[0167]

[Chemical 32] As described above, the silica-based coating film 13 according to this example was obtained. (Example 3) This example 3 corresponds to the second aspect of the present invention and relates to the preparation of a solution for forming a silica-based film. More details are as follows.

First, in a dry atmosphere with a relative humidity of 5%, anhydrous silica fine particles (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil 300) and tetrachlorosilane (as a chlorosilane compound) were added to dimethylsilicon as the first non-aqueous organic solvent. SiCl ₄ ) was mixed and dissolved to prepare a solution C (third mixed solution). The concentration of SiCl _{4 in} the solution C was 0.1 M / l. Further, as anhydrous silica fine particles,
Aerosil 300 was 3% by weight.

Next, chloroform as the second non-aqueous organic solvent was mixed with water until it was saturated to prepare a solution D (fourth mixed solution). At this time, the anhydrous silica fine particles may be added to the solution D or may be added to both solutions.

Subsequently, the solution C and the solution D are treated with the above S.
iCl_FourHumidity of 5% so that the number of moles of water and water are the same.
Mix in a dry atmosphere and let stand overnight. At this time, Si
Cl _FourAnd water cause dehydrochlorination reaction, and chlorosiloxane
A silica-based film-forming solution containing an oligomer was obtained.

Qualitative analysis (liquid chromatography, infrared spectroscopy, etc.) of the silica film-forming solution according to this example was carried out, and the following general formulas (VII), (VIII), (I
It was found that the substance represented by X) was contained.

[0172]

[Chemical 33] (In the formula, n is an integer of 1 or more.)

[0173]

[Chemical 34] (In the formula, n is an integer of 1 or more.)

[0174]

[Chemical 35] (In the formula, n is an integer of 1 or more.) (Example 4) In this example, the silica-based film was formed using the solution for forming a silica-based film prepared in Example 3 above.

First, the base material 21 made of glass was thoroughly degreased by thoroughly washing it. Next, the silica-based coating film forming solution is added to the base material 2 in a dry atmosphere with a humidity of 5%.
It was applied to one surface. Further, dimethyl silicon and chloroform were evaporated at room temperature to form a chlorosiloxane oligomer coating film 22 containing anhydrous silica fine particles 23 (see FIG. 3).

Subsequently, the base material 21 having the chlorosiloxane oligomer coating film 22 formed thereon was exposed to an atmosphere containing water to react the water with the chlorosiloxane oligomer. As a result, the silica-based coating film 24 having a thickness of about 500 nm was formed (see FIG. 4). Here, it was confirmed by analysis that the silica-based coating 24 was configured to include a structural unit represented by the following structural formula (XIII).

[0177]

[Chemical 36] As described above, the silica-based coating film 24 according to this example was obtained.

[0178]

The present invention is carried out in the form described above, and has the following effects.

That is, according to the solution for forming a silica-based coating film according to the first aspect of the present invention, the conventional sol-gel method etc. can be obtained by including a siloxane compound having an activating group in the solution for forming a silica-based coating film. As described above, it is possible to provide a solution for forming a silica-based coating film that can be used without heat treatment or addition of a catalyst and that has excellent reactivity with a substrate.

Further, according to the method for producing a solution for forming a silica-based coating film according to the first aspect of the present invention, a first mixed solution in which a silane compound having an activating group is dissolved in a dry atmosphere, and an oligomerization. A second mixed solution in which water as an agent is dissolved is mixed in a dry atmosphere to prepare a silica-based film forming solution containing a siloxane compound having an activating group. Since the siloxane compound having an activating group is produced by a dehydrochlorination reaction between a silane compound having an activating group and water, it can be a compound having a large number of activating groups. Therefore, there is an effect that a silica-based coating film forming solution having excellent reactivity with the substrate can be produced.

The silica-based coating film according to the first aspect of the present invention is chemically adsorbed to the surface of the substrate by the dehydrochlorination reaction, and has a network structure due to the cross-linking bond by the siloxane bond. It can be used as a hard coat layer for improving the abrasion resistance and scratch resistance of the above base material. Moreover,
Since the silica-based coating does not contain impurities such as hydrocarbon groups in the chemical structure and has an extremely high purity, it has an effect of being excellent in hardness and transparency.

Furthermore, according to the method for producing a silica-based coating film according to the first aspect of the present invention, a solution for forming a silica-based coating film is applied to a substrate to form a siloxane compound coating film, and then the siloxane compound coating film is formed. Since a silica-based coating is formed by reacting with water, it is possible to form the silica-based coating very easily without the need for the addition of a catalyst and the heat treatment step which are performed by the conventional sol-gel method or the like. .

Further, according to the solution for forming a silica-based coating film according to the second aspect of the present invention, a compound in which a silane compound having an activating group is bonded to anhydrous silica fine particles in the solution for forming a silica-based coating film. By including, it can be used without heat treatment or catalyst addition like the conventional sol-gel method,
It is possible to provide a solution for forming a silica-based coating film, which has excellent reactivity with a base material and which has excellent coating properties and whose viscosity can be controlled.

Further, according to the method for producing a solution for forming a silica-based coating film according to the second aspect of the present invention, at least one of the third mixed solution and the fourth mixed solution in which anhydrous silica fine particles are dispersed is used. Then, a third mixed solution in which a silane compound having an activating group is dissolved in a first non-aqueous organic solvent in a dry atmosphere, and a fourth mixed solution in which water is mixed in a second non-aqueous organic solvent. By mixing in a dry atmosphere, a silica-based film-forming solution containing a compound in which a silane compound having an activating group is bonded to anhydrous silica fine particles is prepared. Accordingly, by appropriately setting the addition amount of anhydrous silica fine particles and the like, it is possible to prepare a silica-based coating film forming solution having excellent reactivity with the substrate and coating property while controlling the viscosity.

The silica-based coating film according to the second aspect of the present invention is bonded to the anhydrous silica fine particles and the substrate present in the film through a siloxane bond, and has a network structure due to a cross-linking bond by the siloxane bond. Therefore, it can be used as a hard coat layer for improving the abrasion resistance and scratch resistance of the above-mentioned base material. In addition, since the silica-based coating does not contain impurities such as hydrocarbon groups in the chemical structure and has an extremely high purity, it has an effect of being a thick film and having excellent hardness and transparency.

Further, according to the method for producing a silica-based coating film according to the second aspect of the present invention, the solution for forming a silica-based coating film is
After forming a siloxane compound film having an activating group by coating on a substrate surface in a dry atmosphere and drying, the siloxane compound film is brought into contact with water molecules to contain anhydrous silica fine particles on the substrate surface. Since the silica-based coating film is formed, the effect of being able to form a thick silica-based coating film very easily without the need for the addition of a catalyst and the heat treatment step which have been performed by the conventional sol-gel method or the like is achieved.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an outline of a chlorosiloxane oligomer coating film according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing an outline of the silica-based coating film according to the first embodiment.

FIG. 3 is a schematic sectional view showing an outline of a chlorosiloxane oligomer coating film according to Embodiment 2 of the present invention.

FIG. 4 is a schematic sectional view showing an outline of a silica-based coating film according to the second embodiment.

[Explanation of symbols]

11, 21 Base material 12,22 Chlorosiloxane oligomer coating 13, 24 Silica-based coating 23 Anhydrous silica fine particles

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09J 183/04 C09J 183/04 H01L 21/312 H01L 21/312 C (72) Inventor Tadashi Otake Kadoma Osaka Prefecture 1006 City Kadoma Matsushita Electric Industrial Co., Ltd. (72) Inventor Yukio Nomura Osaka Prefecture Kadoma City 1006 Kadoma Matsushita Electric Industrial Co., Ltd. F term (reference) 4J035 AA02 LA03 LB01 LB02 LB20 4J038 AA011 DL042 DL052 DL072 DL082 HA HA216 HA436 HA441 HA446 JA01 JA09 JA11 JC32 JC35 KA06 KA14 KA20 LA03 LA06 MA07 MA10 PA18 PA19 4J040 AA011 EK042 EK052 EK062 EK072 HA136 HA301 HA306 HB01 HB04 AC32 A08 A05 A04 A04 QB04 A04 A04 QB04 A04 QB04 JB04 QB04 JB05 QA04 QB04 JB05 QA04 QB04 JB05 J04 QB04 JB05 QA04 QB04 JB04 JB05 QA04 QB04 JB05 QA04 QB04 JB04 QB04 QB04 JB05 J04 QB04 JB05 QA04 QB04 JB05 QA04 QB04 JB04 QB04 JB04 QB04 JB05 QAQAQAQQAQAQAQAQAQQQAQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQHQHQHQ but

Claims (27)

[Claims] 1. A silica-based coating formed on the surface of a substrate through a siloxane bond, wherein the silica-based coating does not contain a hydrocarbon group in its chemical structure. 2. The silica-based coating according to claim 1, comprising a repeating structural unit represented by the following structural formula (V). [Chemical 1] 3. The base material according to claim 1, wherein the base material has a functional group having active hydrogen on its surface, and the heat resistance thereof is 150 ° C. or lower. Silica-based coating. 4. A silica-based coating film forming solution comprising a non-aqueous organic solvent and a compound in which a silane compound having an activating group is bonded to anhydrous silica fine particles. 5. The silica-based coating forming solution according to claim 4, wherein titanium oxide fine particles are contained in place of the anhydrous silica fine particles. 6. A silane compound having an activating group,
And include a compound represented by the following general formula (VI):
The silica-based coating according to claim 4 or 5, characterized in that
Forming solution. [Chemical 2] (In the formula, R⁷~ R^TenAre each independently a hydrogen atom,
Rogen, isocyanate group, hydroxyl group, chlorosilane
A functional group containing a ryl group, a functional group containing a dichlorosilyl group,
Contains functional group containing trichlorosilyl group, silanol group
Crosslinks by forming functional groups and siloxane bonds
Represents a silicon-containing functional group to be obtained, R¹¹And R ¹²Are each
Independently, hydrogen atom, halogen, isocyanate group and
It represents a hydroxyl group, and m is an integer of 1 or more. ) 7. The non-aqueous organic solvent is at least one organic solvent selected from a hydrocarbon organic solvent, a fluorine organic solvent and a chlorine organic solvent. 6. The silica-based coating film forming solution according to any one of 6 above. 8. The silica-based coating forming solution according to any one of claims 4 to 7, wherein the silica-based coating forming solution further contains an alkoxysilane compound. . 9. The solution for forming a silica-based coating film according to claim 8, wherein the alkoxysilane compound is at least one compound selected from tetraethoxysilane and propyloxysilane. 10. A step of dissolving a silane compound having an activating group in a first non-aqueous organic solvent in a dry atmosphere to prepare a third mixed solution, and mixing water in the second non-aqueous organic solvent. A step of producing a fourth mixed solution; and a step of mixing the third mixed solution and the fourth mixed solution in a dry atmosphere in order to react the silane compound having an activating group with water, A method for producing a silica-based coating film-forming solution, characterized in that anhydrous silica fine particles are dispersed in at least one of the third mixed solution and the fourth mixed solution. 11. The method for producing a solution for forming a silica-based coating film according to claim 10, wherein titanium oxide fine particles are used in place of the anhydrous silica fine particles. . 12. The method for producing a silica film-forming solution according to claim 10, wherein the molar ratio of the water to the silane compound having an activating group is not more than equimolar. 13. The silica-based coating film forming solution according to claim 10, wherein a chlorosilane compound is used as the silane compound having an activating group. Manufacturing method. 14. The first non-aqueous organic solvent and the second non-aqueous organic solvent are at least one organic solvent selected from a hydrocarbon organic solvent, a fluorine organic solvent and a chlorine organic solvent. The method for producing the silica-based film forming solution according to any one of claims 10 to 13, which is characterized. 15. A silica-based coating formed on the surface of a base material through a siloxane bond, wherein the silica-based coating contains anhydrous silica fine particles, and the anhydrous silica fine particles are siloxane-bonded to the silica-based coating and the base material. The silica-based coating is characterized in that it does not contain a hydrocarbon group in the chemical structure of the silica-based coating. 16. The silica-based coating according to claim 15, wherein titanium oxide fine particles are contained in place of the anhydrous silica fine particles. 17. The silica-based coating according to claim 15 or 16, comprising a repeating structural unit represented by the following structural formula (V). [Chemical 3] 18. The base material has a functional group having active hydrogen on its surface, and the heat resistance of the base material is 150.
The silica-based coating film according to any one of claims 15 to 17, wherein the temperature is not higher than ° C. 19. A coating step of coating the surface of a base material with the solution for forming a silica film according to claim 4 in a dry atmosphere, and evaporating the non-aqueous organic solvent. And a drying step for forming a siloxane compound coating having an activating group, and a silica-based coating formation in which the siloxane compound coating is brought into contact with water molecules to form a silica-based coating containing anhydrous silica fine particles on the surface of the base material. A method for producing a silica-based coating film, which comprises: 20. The method for producing a silica-based coating according to claim 19, wherein the step of forming the silica-based coating is performed in an atmosphere containing water. 21. The method for producing a silica-based coating according to claim 19, further comprising a heat treatment step of heating at a temperature of 100 ° C. or higher after the step of forming the silica-based coating. 22. A coating step of coating the surface of an object with the solution for forming a silica-based coating according to claim 4 in a dry atmosphere, and a silica-based coating on the surface of the object. An adhesion step of adhering the object and another object via a film forming solution; a drying step of evaporating the non-aqueous organic solvent to form a siloxane compound film having an activating group; And a silica-based coating forming step of forming a silica-based coating on the surface of the base material by bringing the compound coating into contact with water molecules. 23. A method according to any one of claims 1 to 3 or claim 1.
An adhesive structure comprising an object and another object adhered to each other via the silica-based coating film according to any one of claims 5 to 18. 24. A coating composition comprising the solution for forming a silica-based coating film according to any one of claims 4 to 9. 25. The coating composition according to claim 24, wherein the coating composition contains any one selected from the group consisting of pigments, dyes and pigments. 26. A method according to any one of claims 1 to 3 or claim 1.
The silica-based coating film according to any one of claims 5 to 18, wherein the passivation film for a semiconductor device comprises the silica-based coating film. 27. A method according to any one of claims 1 to 3, or 1.
The passivation film for a thin film transistor array according to any one of claims 5 to 18, wherein the passivation film for the thin film transistor array comprises the silica based film.