JP2022019380A - Substrate with silica film - Google Patents

Abstract

To provide a substrate with silica film that has excellent alkali resistance and wear resistance.SOLUTION: A substrate with silica film of the present invention has a silica film that is formed by using a composition for forming silica film, and the composition contains a hydrolyzable compound or the like and a silica particle, and the composition contains, as a hydrolyzable compound, only tetraalkoxysilane, a compound represented by the formula I (R3-p(L)pSi-Q-Si(L)pR3-p), and optionally-used fluoroalkylsilane having a hydrolyzable group, and the contained amount of tetraalkoxysilane, the compound represented by the formula I and the silica particle in terms of SiO2 is 2 to 35 mass%, 15 to 88 mass%, 10 to 60 mass% for the total amount of tetraalkoxysilane, the compound represented by the formula I and the silica particle in terms of SiO2, respectively. In the formula I, R is a hydrogen atom or the like, L is a hydrolyzable group, Q is a divalent hydrocarbon group having 2 to 6 carbon atoms, R1 is a hydrogen atom, etc., and p is an integer of 1 to 3.SELECTED DRAWING: None

Description

The present invention relates to a substrate with a silica film.

A method of forming a film on the surface of a substrate is known for the purpose of protecting the substrate and imparting a desired function.
For example, in Patent Document 1, a coating liquid containing a silica precursor such as tetraalkoxysilane and bis (trimethoxysilyl) alkane, silica particles, and a solvent is applied to the surface of a chemically strengthened glass plate and dried. , A method of forming a functional film on the surface of a glass substrate is disclosed.

International Publication No. 2015/186753

In recent years, there has been a demand for further performance improvement of a film arranged on the surface of a substrate such as a resin substrate, a metal substrate and a ceramic substrate. For example, a film having excellent alkali resistance and wear resistance is required.
When the present inventors formed a film on a substrate using the coating liquid described in Patent Document 1, they found that although the film had excellent wear resistance, there was room for improvement in alkali resistance. ..

Therefore, an object of the present invention is to provide a substrate with a silica film having excellent alkali resistance and abrasion resistance.

As a result of diligent studies on the above problems, the present inventors have made a composition for forming a silica film in which the contents of tetraalkoxysilane, a compound represented by the formula I described later, and silica particles in terms of SiO ₂ are each within a predetermined range. We have found that a substrate with a silica film having excellent alkali resistance and abrasion resistance can be obtained by using a compound, and have reached the present invention.

That is, the inventors have found that the above problem can be solved by the following configuration.
[1] A substrate with a silica film, comprising a substrate and a silica film arranged on the substrate and formed by using a composition for forming a silica film.
The substrate is a resin substrate, a metal substrate, a ceramics substrate, or a laminate of these substrates.
The composition for forming a silica film contains at least one selected from the group consisting of a hydrolyzable compound, a hydrolyzate thereof, and a hydrolyzed condensate thereof, and silica particles.
The composition for forming a silica film contains only tetraalkoxysilane, a compound represented by the formula I, and optionally used fluoroalkylsilane having a hydrolyzable group as the hydrolyzable compound.
The content of the tetraalkoxysilane in terms of SiO ₂ is 2 to 35 mass with respect to the total amount of the tetraalkoxysilane, the compound represented by the above formula I, and the silica particles in terms of SiO ₂ . % And
The content of the compound represented by the above formula I in terms of SiO ₂ is relative to the total amount of the tetraalkoxysilane, the compound represented by the above formula I, and the silica particles in terms of SiO ₂ . 15-88% by mass,
The content of the silica particles in terms of SiO ₂ is 10 to 60% by mass with respect to the total amount of the tetraalkoxysilane, the compound represented by the above formula I, and the silica particles in terms of SiO ₂ . A substrate with a silica film.
R _3-p (L) _p Si-Q-Si (L) _p R _3-p formula I
In the above formula I,
R has one or more groups selected from the group consisting of -O-, -S-, -C (O)-and -N (R ¹ )-between hydrogen atoms or carbon-carbon atoms. It is a monovalent hydrocarbon group which may be used, and R ¹ is a hydrogen atom or a monovalent hydrocarbon group.
L is a hydrolyzable group
Q may have one or more groups selected from the group consisting of -O-, -S-, -C (O)-and -N (R ² )-between carbons and carbon atoms. , A divalent hydrocarbon group having 2 to 6 carbon atoms, and R ² is a hydrogen atom or a monovalent hydrocarbon group.
p is an integer of 1 to 3.
[2] The content of the compound represented by the above formula I in terms of SiO ₂ is the total amount of the tetraalkoxysilane, the compound represented by the above formula I, and the silica particles in terms of SiO ₂ . On the other hand, the substrate with a silica film according to [1], which is 30 to 50% by mass.
[3] The substrate with a silica film according to [1] or [2], wherein the composition for forming a silica film further contains a metal catalyst.

According to the present invention, it is possible to provide a substrate with a silica film having excellent alkali resistance and abrasion resistance.

It is sectional drawing which shows typically an example of the substrate with a silica film of this invention.

The meanings of the terms in the present invention are as follows.
The numerical range represented by using "-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.

The "content in terms of SiO ₂ " means the mass when all the silicon atoms contained in the compound are converted to SiO ₂ .
For example, since tetraethoxysilane contains one silicon atom, the content of 100 g of tetraethoxysilane (molecular weight: 208.33) in terms of SiO ₂ is the molecular weight of one SiO ₂ (60. Calculated based on 8), it is 29.2 g.
Further, since 1,6-bis (trimethoxysilyl) hexane contains two silicon atoms, 100 g of 1,6-bis (trimethoxysilyl) hexane (molecular weight: 326.5) is converted into SiO ₂ . The content of is 37.3 g when calculated based on the molecular weight (60.8 × 2) of two SiO ₂ .

[Substrate with silica film]
The substrate with a silica film of the present invention has a substrate and a silica film arranged on the substrate and formed by using the composition for forming a silica film.
The substrate is a resin substrate, a metal substrate, a ceramics substrate, or a laminate of these substrates.
Further, the composition for forming a silica film contains at least one selected from the group consisting of a hydrolyzable compound, a hydrolyzate thereof, and a hydrolyzed condensate thereof, and silica particles.
Further, in the composition for forming a silica film, as the hydrolyzable compound, tetraalkoxysilane, a compound represented by the formula I described later (hereinafter, also referred to as “compound I”), and water optionally used. Includes only fluoroalkylsilanes with degradable groups.
Further, the contents of the tetraalkoxysilane, the compound I, and the silica particles in terms of SiO ₂ are the total mass of the tetraalkoxysilane, the compound I, and the silica particles in terms of SiO ₂ , respectively. On the other hand, it is 2 to 35% by mass, 15 to 88% by mass, and 10 to 60% by mass.
The substrate with a silica film of the present invention is excellent in alkali resistance and abrasion resistance. The details of this reason have not been clarified, but it is presumed that it is due to the following reasons.

In the composition for forming a silica film in the present invention, the content of tetraalkoxysilane in terms of SiO ₂ is within a predetermined range. As a result, it is presumed that the hardness of the silica film was improved and a substrate with a silica film having excellent wear resistance was obtained.
Further, the composition for forming a silica film in the present invention has a higher content of compound I (converted to SiO ₂ ) than the composition in Patent Document 1. As described above, when the content of the compound I in the composition for forming a silica film is large, a silica film containing a large amount of carbon-carbon atom bonds derived from "Q" of the formula I can be obtained. Since the carbon-carbon atom bond is more difficult to break due to the action of alkali than the silicon-oxygen atom bond, it is presumed that the alkali resistance of the silica film is improved.
Further, the carbon-carbon atom bond derived from "Q" of the formula I plays a role of closing the fine holes formed in the silica film, thereby suppressing the invasion of ions and improving the alkali resistance of the silica film. It is presumed that it was done. Fine holes are formed by the volatilization of the residual solvent and the hydrolysis condensation reaction.
Further, the substrate with a silica film of the present invention is also excellent in salt water resistance. The details of this reason have not been clarified, but it is presumed to be the same as the above-mentioned reason for excellent alkali resistance.

When the substrate in the present invention is made of a flammable (for example, resin) material, having a silica film can suppress combustion of the substrate with a silica film. The reason for this is thought to be as follows. When a flame is brought close to the surface of the silica film, the surface of the substrate becomes oxygen-deficient due to the silica film, so that a flame-retardant carbonized layer is formed on the surface of the substrate. As a result, it is presumed that the silica layer and the flame-retardant carbonized layer can block oxygen and heat and suppress the combustion of the substrate.
Further, when the substrate in the present invention is a metal substrate, the silica film existing on the surface of the metal substrate can suppress the contact of water, acid, salt, oxygen, etc. with the metal substrate, so that the metal substrate is not corroded. Can be suppressed.
Further, since the silica film in the present invention has a dense structure, dirt does not easily penetrate into the film. Therefore, the substrate with a silica film of the present invention is also excellent in antifouling property.

FIG. 1 is a cross-sectional view schematically showing an example of the substrate with a silica film of the present invention. The substrate 1A with a silica film has a substrate 10 and a silica film 20 formed on one surface of the substrate 10.
In the example of FIG. 1, the silica film 20 is formed on the entire surface of one surface of the substrate 10, but the present invention is not limited to this, and the silica film 20 may be formed only on a part of the region of the substrate 10. ..
In the example of FIG. 1, the silica film 20 is formed on only one surface of the substrate 10, but the present invention is not limited to this, and the silica film 20 may be formed on both sides of the substrate 10.
Hereinafter, each member of the substrate 1A with a silica film will be described.

〔substrate〕
The substrate 10 is a resin substrate, a metal substrate, a ceramics substrate, or a laminate of these substrates.
Specific examples of the material constituting the resin substrate include acrylic resin, methacrylic resin, polyolefin resin, polyester resin, polycarbonate resin, vinyl chloride resin, epoxy resin, and polyimide resin. These materials may be used alone or in combination of two or more.
Specific examples of the materials constituting the metal substrate include aluminum, titanium, copper, nickel, stainless steel, brass, magnesium, iron and alloys thereof. These materials may be used alone or in combination of two or more.
Specific examples of the material constituting the ceramic substrate include zirconium oxide, aluminum oxide, silicon oxide, titanium oxide, lead zirconate titanate, ferrite, boron nitride, and silicon carbide. These materials may be used alone or in combination of two or more.
When the substrate 10 is a laminated body, for example, a laminated body in which a resin substrate (resin layer) is arranged on a metal substrate (metal layer) can be mentioned.

The surface of the substrate 10 may be smooth, may have irregularities on the surface, or may have a curved surface shape.
The thickness of the substrate 10 is appropriately selected depending on the intended use, and is not particularly limited, but is preferably 50 to 10,000 nm.

[Silica film]
The silica film 20 is formed by using the composition for forming a silica film described later, and contains at least a hydrolyzed condensate of a hydrolyzable compound contained in the composition for forming a silica film and silica particles.

The thickness of the silica film 20 is preferably 50 to 10,000 nm, more preferably 100 to 7,000 nm, and particularly preferably 150 to 5,000 nm because the effect of the present invention is more excellent.
The thickness of the silica film 20 is measured by the method described in the Examples column below.

Specific examples of the use of the silica film 20 include a protective film of the substrate 10 (for example, a scratch prevention film, an antifouling film, a flame retardant film, an alkali barrier film, an antioxidant film, a moisture absorption prevention film, and a corrosion prevention film). ..

<Composition for forming a silica film>
The composition for forming a silica film is at least one selected from the group consisting of a hydrolyzable compound, a hydrolyzate thereof, and a hydrolyzable condensate thereof (hereinafter, also simply referred to as "hydrolyzable compounds"). And silica particles.
The composition for forming a silica film contains only tetraalkoxysilane, compound I, and optionally used fluoroalkylsilane having a hydrolyzable group as a hydrolyzable compound.

(Hydrolytic compounds)
Specific examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, and tetratetrabutoxysilane.
The tetraalkoxysilane may be used alone or in combination of two or more.

Compound I is a compound represented by the following formula I.
R _3-p (L) _p Si-Q-Si (L) _p R _3-p formula I

In Formula I, R is a hydrogen atom or a monovalent hydrocarbon group.
Specific examples of the monovalent hydrocarbon group include an alkyl group, an alkenyl group and an aryl group. The alkyl group may be linear, branched or cyclic.
The number of carbon atoms of the monovalent hydrocarbon group is preferably 1 to 10, and more preferably 1 to 6.
A monovalent hydrocarbon group has one or more groups selected from the group consisting of -O-, -S-, -C (O)-and -N (R ¹ )-between carbon atoms. You may be doing it. R ¹ is a hydrogen atom or a monovalent hydrocarbon group.
When there are two or more Rs in the formula I, the two or more Rs may be the same or different.

In formula I, L is a hydrolyzable group.
Specific examples of the hydrolyzable group include an alkoxy group, an asyloxy group, a ketooxime group, an alkenyloxy group, an amino group, an aminoxy group, an amide group, an isocyanate group, a halogen atom and the like. Of these, an alkoxy group, an isocyanate group, and a halogen atom (particularly, a chlorine atom) are preferable from the viewpoint of the balance between the stability of the compound I and the ease of hydrolysis.
As the alkoxy group, an alkoxy group having 1 to 3 carbon atoms is preferable, and a methoxy group or an ethoxy group is particularly preferable.
In the formula I, two or more L's may be the same or different.

Q is a divalent hydrocarbon group having 2 to 6 carbon atoms.
Examples of the divalent hydrocarbon group include an alkylene group, an alkenylene group, an arylene group and the like, and an alkylene group is preferable. The alkylene group may be linear, branched or cyclic.
A divalent hydrocarbon group has one or more groups selected from the group consisting of -O-, -S-, -C (O)-and -N (R ² )-between carbon atoms. You may be doing it. R ² is a hydrogen atom or a monovalent hydrocarbon group.

p is an integer of 1 to 3, and 2 or 3 is preferable from the viewpoint of reaction rate, and 3 is particularly preferable.

Compound I may be used alone or in combination of two or more.

Fluoroalkylsilane having a hydrolyzable group is a component optionally used as a hydrolyzable compound. When a fluoroalkylsilane having a hydrolyzable group is used, the wear resistance of the substrate with a silica film is further improved.

The fluoroalkylsilane having a hydrolyzable group is preferably a compound represented by the formula II because the effect of the present invention is more excellent.
RF-Q ¹⁰ -Si (L ¹⁰ ) _p1 ^{R 10} _3-p1 formula II

In Formula II, ^RF is a fluoroalkyl group, preferably a perfluoroalkyl group. The fluoroalkyl group may be linear, branched or cyclic.
The number of carbon atoms of the fluoroalkyl group is preferably 1 to 8, and particularly preferably 4 to 8.

In Formula II, ^Q10 is a divalent linking group.
Specific examples of a divalent linking group include one or more selected from the group consisting of —O—, —S—, —C (O) − and —N (R ¹¹ ) —between carbon and carbon atoms. A divalent hydrocarbon group which may have a group, -O-, -S-, -C (O) O-, -C (O)-, -C (O) -N (R ¹² )- , And a group in which two or more of these groups are combined. R ¹¹ and R ¹² are each independently a hydrogen atom or a monovalent hydrocarbon group. The definition of a monovalent hydrocarbon group is the same as R in Formula I above.
The preferred embodiment of the divalent hydrocarbon group is the same as Q in the above formula I. However, the number of carbon atoms of the divalent carbonized water group is preferably 1 to 6, and particularly preferably 2 to 6.
Among them, the divalent linking group is preferably a divalent hydrocarbon group, more preferably an ethylene group.

In Formula II, ^L10 is a hydrolyzable group. The definition of hydrolyzable group is the same as L in Formula I above.
When there are two or more L ^10s in Formula II, the two or more L ^10s may be the same or different.

^In Formula II, R10 is a hydrogen atom or a monovalent hydrocarbon group. The definition of a monovalent hydrocarbon group is the same as R in Formula I above.
When there are two or more R ^10s in Formula II, the two or more R ^10s may be the same or different.

p1 is an integer of 1 to 3, and 2 or 3 is preferable from the viewpoint of reaction rate, and 3 is particularly preferable.

The fluoroalkylsilane having a hydrolyzable group may be used alone or in combination of two or more.

The hydrolyzate of a hydrolyzable compound is intended to be a compound obtained by hydrolyzing a hydrolyzable group in the hydrolyzable compound. The above hydrolyzed product is one in which all of the hydrolyzable groups are hydrolyzed (completely hydrolyzed product), but a part of the hydrolyzable groups is hydrolyzed (partially hydrolyzed). It may be a thing). That is, the hydrolyzate may be a complete hydrolyzate, a partial hydrolyzate, or a mixture thereof.
The hydrolyzed condensate of the hydrolyzable compound is intended to be a compound obtained by hydrolyzing a hydrolyzable group in the hydrolyzable compound and condensing the obtained hydrolyzate. The hydrolyzed condensate may be partially hydrolyzed even if all hydrolyzable groups are hydrolyzed and all the hydrolyzated products are condensed (completely hydrolyzed condensate). The sex group may be hydrolyzed and a part of the hydrolyzate may be condensed (partially hydrolyzed condensate). That is, the hydrolyzed condensate may be a completely hydrolyzed condensate, a partially hydrolyzed condensate, or a mixture thereof. Further, the hydrolyzed condensate may be a hydrolyzed condensate obtained by condensing hydrolyzates of two or more kinds of hydrolyzable compounds with each other.

(Silica particles)
The silica particles are particles containing silica (SiO ₂ ).
Specific examples of the shape of the silica particles include a spherical shape, an elliptical shape, a needle shape, a plate shape, a rod shape, a cone shape, a columnar shape, a cube shape, a rectangular parallelepiped shape, a diamond shape, a star shape, and an indefinite shape.
The silica particles may be solid particles, hollow particles, or porous particles. By "solid particle" is meant a particle that does not have a cavity inside. "Hollow particle" means a particle having a cavity inside. By "porous particle" is meant a particle having a plurality of pores on its surface.
The silica particles may exist in an independent state, the particles may be connected in a chain, or the particles may be aggregated.

The average agglomerated particle diameter of the silica particles is preferably 5 to 100 nm, and particularly preferably 5 to 50 nm, because the effect of the present invention is more excellent.
The average aggregated particle diameter of the silica particles means a volume-based cumulative 50% diameter (D50) measured using a laser diffraction type particle size distribution measuring device.

As the silica particles, a commercially available product may be used, and examples thereof include the Snowtex series manufactured by Nissan Chemical Industries, Ltd.
The silica particles may be used alone or in combination of two or more.

(Metal catalyst)
The composition for forming a silica film preferably contains a metal catalyst from the viewpoint of promoting the hydrolysis and condensation of the hydrolyzable compound.
Specific examples of the metal catalyst include aluminum acetylacetonate, aluminum bisethylacetate monoacetylacetonate, aluminum-di-n-butoxide-monoethylacetoacetate, aluminum-di-isopropoxide-monomethylacetate, and diiso. Aluminum chelate compounds such as propoxyaluminum ethyl acetate; Titanium chelate compounds such as titanium acetylacetonate and titanium tetraacetylacetonate; Copper chelate compounds such as copper acetylacetonate; Chromium chelate compounds such as; Cobalt chelate compounds such as cobalt acetylacetonate; Tin chelate compounds such as tin acetylacetonate; Iron chelate compounds such as iron (III) acetylacetonate; Manganese chelate compounds such as manganese acetylacetonate; Nickel Examples thereof include nickel chelate compounds such as acetylacetonate; zinc chelate compounds such as zinc acetylacetonate; zirconium chelate compounds such as zirconium acetylacetonate; and organic tin compounds such as dialkyltin.
Among them, the metal catalyst is preferably an aluminum chelate compound, and particularly preferably aluminum acetylacetonate, from the viewpoint of promoting the hydrolysis and condensation of the hydrolyzable compound.
The metal catalyst may be used alone or in combination of two or more.

(Liquid medium)
The composition for forming a silica film preferably contains a liquid medium. The liquid medium is preferably a solvent in which the hydrolyzable compound is dissolved or dispersed and the silica particles are dispersed in the composition.

Specific examples of the liquid medium include organic solvents such as alcohols, ketones, ethers, cellosolves, esters, glycol ethers, nitrogen-containing compounds and sulfur-containing compounds, and water.

Specific examples of alcohols include methanol, ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, and diacetone alcohol.
Specific examples of the ketones include acetone, methyl ethyl ketone, and methyl isobutyl ketone.
Specific examples of ethers include tetrahydrofuran and 1,4-dioxane.
Specific examples of cellosolves include methyl cellosolve, ethyl cellosolve, and butyl cellosolve.
Specific examples of the esters include methyl acetate and ethyl acetate.
Specific examples of glycol ethers include ethylene glycol monoalkyl ethers.
Specific examples of the nitrogen-containing compound include N, N-dimethylacetamide, N, N-dimethylformamide, and N-methylpyrrolidone.
Specific examples of the sulfur-containing compound include dimethyl sulfoxide.

The liquid medium may be used alone or in combination of two or more.
The liquid medium preferably contains only water or is a mixed solvent of water and an organic solvent from the viewpoint of hydrolyzing the hydrolyzable compound.
When a mixed solvent of water and an organic solvent is used, alcohols are preferable as the organic solvent.

(Other ingredients)
The composition for forming a silica film may contain components other than the above. Specific examples of other components include silicone oils, surfactants, pH regulators (eg, acids, alkalis, etc.) and defoamers.

(Content)
In the composition for forming a silica film, the content of tetraalkoxysilane in terms of SiO ₂ is 2 to 35% by mass with respect to the total amount of tetraalkoxysilane, compound I, and silica particles in terms of SiO ₂ . 5% by mass or more is preferable, 7% by mass or more is more preferable, and 15% by mass or more is particularly preferable, because of the alkali resistance and salt water resistance of the substrate with a silica film. From an excellent point of view, 30% by mass or less is preferable, and 20% by mass or less is particularly preferable.

In the composition for forming a silica film, the content of compound I in terms of SiO ₂ is 15 to 88% by mass with respect to the total amount of tetraalkoxysilane, compound I, and silica particles in terms of SiO ₂ . 20% by mass or more is preferable, 25% by mass or more is particularly preferable, and 60% by mass or less is particularly preferable from the viewpoint of being excellent in abrasion resistance of the substrate with a silica film. It is preferable, 55% by mass or less is more preferable, and 50% by mass or less is particularly preferable.

In the composition for forming a silica film, the content of silica particles in terms of SiO ₂ is 10 to 60% by mass with respect to the total amount of tetraalkoxysilane, compound I, and silica particles in terms of SiO ₂ . 30% by mass or more is preferable, 32% by mass or more is preferable, 35% by mass or more is particularly preferable, and the substrate with a silica film is more excellent in alkali resistance and salt water resistance because it is more excellent in abrasion resistance of the substrate with a silica film. Therefore, 50% by mass or less is preferable, 48% by mass or less is more preferable, and 45% by mass or less is particularly preferable.

When the composition for forming a silica film contains fluoroalkylsilane having a hydrolyzable group, the content of the fluoroalkylsilane having a hydrolyzable group in terms of SiO ₂ in the composition for forming a silica film is tetraalkoxysilane. In terms of SiO ₂ , the total amount of the compound I, the silica particles, and the fluoroalkylsilane having a hydrolyzable group is 0.1% by mass because the substrate with the silica film is more excellent in wear resistance. The above is preferable, 0.5% by mass or more is particularly preferable, and 5% by mass or less is particularly preferable, and 3% by mass or less is particularly preferable, from the viewpoint of being superior in alkali resistance and salt water resistance of the substrate with a silica film.

When the composition for forming a silica film contains a metal catalyst, the content of the metal catalyst is SiO of tetraalkoxysilane, compound I, silica particles, and optionally used fluoroalkylsilane having a hydrolyzable group. 0.01 to 5% by mass is preferable, and 0.1 to 3% by mass is particularly preferable with respect to the total amount in terms of ₂ .

When the composition for forming a silica film contains the above-mentioned other components, the content of the other components is tetraalkoxysilane, compound I, silica particles, and a fluoroalkylsilane having a hydrolyzable group optionally used. 0.1 to 3% by mass is preferable, and 0.5 to 2% by mass is particularly preferable with respect to the total amount of the above in terms of SiO ₂ .

When the silica film forming composition contains a liquid medium, the content of the liquid medium is preferably 86.0 to 99.5% by mass, preferably 88.5 to 99% by mass, based on the total mass of the silica film forming composition. .0% by mass is particularly preferable.

(Preparation method)
The composition for forming a silica film can be produced by mixing a hydrolyzable compound, silica particles and an optional component (for example, a metal catalyst, a liquid medium).

[Use]
The application of the substrate 1A with a silica film is not particularly limited, but includes vehicle parts (members that come into contact with people such as vehicle bodies, display units and operation parts), industrial equipment, building exterior members, sanitary members, and the like. Be done.

[Manufacturing method of substrate with silica film]
Examples of the method for manufacturing the substrate 1A with a silica film include a method of applying the above-mentioned composition for forming a silica film on the substrate 10 and drying it if necessary to form the silica film 20 on the substrate 10.

The coating method includes spin coating method, spray coating method, dip coating method, die coating method, curtain coating method, screen coating method, inkjet method, flow coating method, gravure coating method, bar coating method, flexographic coating method, and slit coating method. , Wet coat method such as roll coat method.

The drying may be carried out by heating, or may be carried out by natural drying or air drying without heating.
The drying temperature is preferably 50 ° C. or higher, and particularly preferably 100 ° C. or higher, from the viewpoint of excellent hardness of the silica film.
The drying time may be appropriately set depending on the drying temperature, the size of the substrate, and the like, but is preferably 5 minutes or longer, and particularly preferably 10 minutes or longer.

Hereinafter, the present invention will be described in detail with reference to examples. Examples 1 to 6 are examples, and examples 7 to 9 are comparative examples. However, the present invention is not limited to these examples.

[Calculation of silica film thickness]
The thickness of the silica film was determined by the solid content of the composition for forming the silica film and No. 1 of the bar coater. It was calculated from the film thickness at the time of wetting and the solid content density set in.

[Alkali resistance evaluation test]
The substrate with a silica film of each example was immersed in a 0.1 N sodium hydroxide aqueous solution adjusted to 23 ± 2 ° C. for 6 hours, washed with pure water, and dried by air blow.
After drying, the test site was irradiated with light, the degree of white turbidity was visually confirmed, and the alkali resistance was evaluated according to the following criteria. The results are shown in Table 1.
⊚: No cloudiness is observed.
◯: Partial cloudiness is observed.
X: White turbidity is observed on the entire surface.

[Evaluation test for salt water resistance]
The substrate with a silica film of each example was immersed in a 5% sodium chloride aqueous solution adjusted to 50 ± 2 ° C. for 24 hours, washed with pure water, and dried with an air blow.
The dried substrate with silica film was visually observed and the salt water resistance was evaluated according to the following criteria. The results are shown in Table 1.
○: No change in appearance ×: Change in appearance (light spots, unevenness, and cloudiness occur)

[Abrasion resistance evaluation test]
The surface of the silica film in the substrate with the silica film of each example was reciprocated horizontally with a deck brush under a load of 500 g.
After 100 reciprocating motions, the portion rubbed with the deck brush was irradiated with light, the presence or absence of scratches was visually confirmed, and the wear resistance was evaluated according to the following criteria. The results are shown in Table 1.
○: No scratches ×: Scratches

[Preparation of composition A for forming a silica film]
While stirring 22.10 g of denatured ethanol (manufactured by Japan Alcohol Trading Co., Ltd., trade name "Solmix AP-11"), 6.41 g of ion-exchanged water and 0.01 g of aluminum acetylacetonate were added, and the mixture was stirred for 5 minutes.
To this, 0.17 g of tetraethoxysilane, 0.81 g of bis (trimethoxysilyl) hexane, and silica particle dispersion (manufactured by Nissan Chemical Industries, Ltd., trade name "Snowtex OS", SiO ₂ conversion amount: 20% by mass. ) 1.75 g was added and stirred at room temperature for 30 minutes to prepare a composition A for forming a silica film.
In the composition A for forming a silica film, the contents of tetraethoxysilane, bis (trimethoxysilyl) hexane and silica particles in terms of SiO ₂ are the SiO of tetraethoxysilane, bis (trimethoxysilyl) hexane and silica particles, respectively. It was 7% by mass, 43% by mass, and 50% by mass with respect to the total amount in ₂ conversion.

[Preparation of Silica Film Forming Compositions B to F]
The table shows the contents of tetraethoxysilane, bis (trimethoxysilyl) hexane and silica particles in terms of SiO ₂ with respect to the total amount of tetraethoxysilane, bis (trimethoxysilyl) hexane and silica particles in terms of SiO ₂ . The silica film forming compositions B to F were obtained in the same manner as in the preparation of the silica film forming composition A except that the amount of each component used was adjusted so as to be the value described in 1.

[Example 1]
The aluminum substrate (size: 50 mm × 100 mm) was washed with pure water and then air-dried.
After air-drying, the silica film-forming composition A is dropped onto the surface of the substrate, and a coated substrate on which the coating film of the silica film-forming composition A is formed by a bar coating method (bar coater No. 12) is obtained. Made.
The substrate with a coating film is placed in a hot air furnace whose temperature inside the furnace is adjusted to 120 ° C., heated for 15 minutes to cure the coating film, and then cooled at room temperature to obtain the substrate with a silica film of Example 1. Obtained.

[Example 2]
An easy-adhesive PET film (manufactured by Toyobo Co., Ltd., trade name "Cosmo Shine (registered trademark) A4100", size: 50 mm x 100 mm) was used instead of the aluminum substrate. The substrate with the silica film of Example 2 was produced in the same manner as in Example 1 except that 24 was used and the heating time was set to 60 minutes.

[Example 3]
A stainless steel substrate (SUS304, size: 100 mm × 100 mm) was used instead of the aluminum substrate. A substrate with a silica film of Example 3 was produced in the same manner as in Example 1 except that 24 was used and the heating time was set to 60 minutes.

[Examples 4-9]
The same as in Example 1 except that the silica film forming composition shown in Table 1 was used instead of the silica film forming composition A and the coating conditions were adjusted so that the thickness of the silica film became the value shown in Table 1. Then, the substrates with the silica film of Examples 4 to 9 were produced.

[Evaluation results]
The above-mentioned various evaluations were performed using the substrates with silica films of Examples 1 to 9. The results are shown in Table 1.
In Table 1, "content (% by mass) in terms of SiO ₂ " means tetraethoxysilane, bis (triethoxysilyl) hexane, and tetraethoxysilane with respect to the total amount of silica particles in terms of SiO ₂ . It means the content of bis (triethoxysilyl) hexane and silica particles in terms of SiO ₂ .

As shown in Table 1, if a silica film forming composition in which the contents of tetraalkoxysilane, compound I and silica particles in terms of SiO ₂ are within predetermined ranges is used, the alkali resistance, salt water resistance and abrasion resistance are improved. It was confirmed that an excellent substrate with a silica film was obtained (Examples 1 to 6).

1A Substrate with silica film 10 Substrate 20 Silica film

Claims (3)

A substrate with a silica film having a substrate and a silica film arranged on the substrate and formed by using a composition for forming a silica film.
The substrate is a resin substrate, a metal substrate, a ceramics substrate, or a laminate of these substrates.
The composition for forming a silica film contains at least one selected from the group consisting of a hydrolyzable compound, a hydrolyzate thereof, and a hydrolyzed condensate thereof, and silica particles.
The composition for forming a silica film contains only tetraalkoxysilane, a compound represented by the formula I, and optionally used fluoroalkylsilane having a hydrolyzable group as the hydrolyzable compound.
The content of the tetraalkoxysilane in terms of SiO ₂ is 2 to 35 mass with respect to the total amount of the tetraalkoxysilane, the compound represented by the formula I, and the silica particles in terms of SiO ₂ . % And
The content of the compound represented by the formula I in terms of SiO ₂ is relative to the total amount of the tetraalkoxysilane, the compound represented by the formula I, and the silica particles in terms of SiO ₂ . 15-88% by mass,
The content of the silica particles in terms of SiO ₂ is 10 to 60% by mass with respect to the total amount of the tetraalkoxysilane, the compound represented by the formula I, and the silica particles in terms of SiO ₂ . A substrate with a silica film.
R _3-p (L) _p Si-Q-Si (L) _p R _3-p formula I
In the formula I,
R has one or more groups selected from the group consisting of -O-, -S-, -C (O)-and -N (R ¹ )-between hydrogen atoms or carbon-carbon atoms. It is a monovalent hydrocarbon group which may be used, and R ¹ is a hydrogen atom or a monovalent hydrocarbon group.
L is a hydrolyzable group
Q may have one or more groups selected from the group consisting of -O-, -S-, -C (O)-and -N (R ² )-between carbons and carbon atoms. , A divalent hydrocarbon group having 2 to 6 carbon atoms, and R ² is a hydrogen atom or a monovalent hydrocarbon group.
p is an integer of 1 to 3. The content of the compound represented by the formula I in terms of SiO ₂ is relative to the total amount of the tetraalkoxysilane, the compound represented by the formula I, and the silica particles in terms of SiO ₂ . The substrate with a silica film according to claim 1, which is 30 to 50% by mass. The substrate with a silica film according to claim 1 or 2, wherein the composition for forming a silica film further contains a metal catalyst.

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