Silica coated glass substrate

Abstract

A glass substrate with a silica film according to the present invention has a silica film that is formed using a silica-film-forming composition, in which the composition comprises a hydrolysable compound or the like and silica particles / zirconia particles, the hydrolyzable compound comprises only a tetraalkoxysilane, a compound represented by formula I: (R3-p(L)pSi-Q-Si(L)pR3-p) (compound I), a fluoroalkylsilane having a hydrolysable group which is used optionally and a zirconium compound having a hydrolyzable group which is used optionally, and the contents of the tetraalkoxysilane, the compound I, and the silica particles / zirconia particles in terms of SiO2 / ZrO2 content fall within specified ranges, respectively.

Description

[Technical Field]

[0001] The present invention relates to a glass substrate with a silica film. [Background technology]

[0002] BACKGROUND ART Methods for forming a film on the surface of a glass substrate for the purpose of protecting the glass substrate or imparting a desired function to the glass substrate are known. For example, Patent Document 1 discloses a method of forming a functional film on the surface of a glass substrate by applying a coating liquid containing a silica precursor such as tetraalkoxysilane and bis(trimethoxysilyl)alkane, silica particles, and a solvent to the surface of a chemically strengthened glass plate and drying it. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 186753 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for further improvements in the performance of films disposed on the surface of glass substrates, and for example, there has been a demand for films with excellent alkali resistance and abrasion resistance. The present inventors formed a film on a glass substrate using the coating liquid described in Patent Document 1, and found that although the film had excellent abrasion resistance, there was room for improvement in alkali resistance.

[0005] Therefore, an object of the present invention is to provide a glass substrate with a silica film that is excellent in alkali resistance and abrasion resistance. [Means for solving the problem]

[0006] As a result of intensive research into the above-mentioned problems, the inventors have discovered that by using a composition for forming a silica film in which the content of tetraalkoxysilane in terms of SiO2, the content of a compound represented by formula I described below in terms of SiO2, and the content of at least one type selected from the group consisting of silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2 are each within a specified range, a glass substrate with a silica film having excellent alkali resistance and abrasion resistance can be obtained, leading to the present invention.

[0007] That is, the inventors have found that the above problems can be solved by the following configuration. [1] A silica film-coated glass substrate comprising a glass substrate and a silica film disposed on the glass substrate and formed using a silica film-forming composition, the silica film-forming composition comprises at least one selected from the group consisting of hydrolyzable compounds, their hydrolysates, and their hydrolysis condensates, and at least one selected from the group consisting of silica particles and zirconia particles; the hydrolyzable compound contains only a tetraalkoxysilane, a compound represented by formula I, an optionally used fluoroalkylsilane having a hydrolyzable group, and an optionally used zirconium compound having a hydrolyzable group; the content of the tetraalkoxysilane in terms of SiO2 is 2 to 35 mass% based on the total content of the content of the tetraalkoxysilane in terms of SiO2, the content of the compound represented by formula I in terms of SiO2, and the content of at least one kind selected from the group consisting of silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2, the content of the compound represented by the formula I in terms of SiO2 is 15 to 88 mass% based on the total content of the content of the tetraalkoxysilane in terms of SiO2, the content of the compound represented by the formula I in terms of SiO2, and the content of at least one kind selected from the group consisting of silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2, a silica film-coated glass substrate, wherein the content of at least one kind selected from the group consisting of silica particles and zirconia particles, in terms of SiO2 equivalent, ZrO2 equivalent, or SiO2 and ZrO2 equivalent, is 10 to 60 mass % relative to the total content of the content of the tetraalkoxysilane, in terms of SiO2 equivalent, the content of the compound represented by formula I, in terms of SiO2 equivalent, and the content of at least one kind selected from the group consisting of silica particles and zirconia particles, in terms of SiO2 equivalent, ZrO2 equivalent, or SiO2 and ZrO2 equivalent; R 3-p (L) p Si-Q-Si(L) p R 3-p Formula I In the above formula I, R is a hydrogen atom or -O-, -S-, -C(O)- and -N(R 1 )-, and R 1 is a hydrogen atom or a monovalent hydrocarbon group, L is a hydrolyzable group, Q is -O-, -S-, -C(O)- and -N(R 2 )-, and R 2 is a hydrogen atom or a monovalent hydrocarbon group, p is an integer of 1 to 3. [2] The silica-coated glass substrate of [1], wherein the content of the compound represented by the formula I above, calculated as SiO2, is 30 to 50 mass% of the total content of the content of the tetraalkoxysilane calculated as SiO2, the content of the compound represented by the formula I above, calculated as SiO2, and the content of at least one kind selected from the group consisting of silica particles and zirconia particles, calculated as SiO2, ZrO2, or SiO2 and ZrO2. [3] The silica film-coated glass substrate according to [1] or [2], wherein the silica film-forming composition further contains a metal catalyst. [4] The silica film-coated glass substrate according to any one of [1] to [3], further comprising a heat ray reflecting film between the glass substrate and the silica film. [5] The heat ray reflective film has a silver-containing layer and an upper layer consisting of all layers arranged on the silica film side of the silver-containing layer, The silica film-attached glass substrate according to [4], wherein the ratio of the thickness of the silica film to the thickness of the upper layer is 0.5 to 30. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a glass substrate with a silica film that is excellent in alkali resistance and abrasion resistance. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of a silica-coated glass substrate of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an example of a silica-coated glass substrate of the present invention. [Figure 3] FIG. 3 is a cross-sectional view schematically showing an example of a silica-coated glass substrate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The terms used in the present invention have the following meanings. A numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0011] "Content in terms of SiO2" means the mass when all silicon atoms contained in a compound are converted into SiO2. For example, since tetraethoxysilane contains one silicon atom, the SiO2 content of 100 g of tetraethoxysilane (molecular weight: 208.33) is 29.2 g, calculated based on the molecular weight of one SiO2 atom (60.8). Also, since 1,6-bis(trimethoxysilyl)hexane contains two silicon atoms, the SiO2 content of 100 g of 1,6-bis(trimethoxysilyl)hexane (molecular weight: 326.5) is 37.3 g, calculated based on the molecular weight of two SiO2 atoms (60.8 x 2). "Content in terms of ZrO2" means the mass when all zirconium atoms contained in the compound are converted to ZrO2.

[0012] [Glass substrate with silica film] The silica film-coated glass substrate of the present invention comprises a glass substrate and a silica film disposed on the glass substrate and formed using a silica film-forming composition. The silica film-forming composition also contains at least one selected from the group consisting of hydrolyzable compounds, their hydrolysates, and their hydrolysis condensates, and at least one selected from the group consisting of silica particles and zirconia particles. The hydrolyzable compound includes only a tetraalkoxysilane, a compound represented by the formula I described below (hereinafter also referred to as "compound I"), an optionally used fluoroalkylsilane having a hydrolyzable group, and an optionally used zirconium compound having a hydrolyzable group. Furthermore, the content of the tetraalkoxysilane in terms of SiO2, the content of the compound I in terms of SiO2, and the content of at least one selected from the group consisting of the silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2 are 2 to 35 mass%, 15 to 88 mass%, and 10 to 60 mass%, respectively, relative to the total content of the content of the tetraalkoxysilane in terms of SiO2, the content of the compound I in terms of SiO2, and the content of at least one selected from the group consisting of the silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2. That is, the contents of the tetraalkoxysilane, the compound I, and the silica particles and / or zirconia particles in terms of SiO2 and / or ZrO2 are 2 to 35 mass%, 15 to 88 mass%, and 10 to 60 mass%, respectively, relative to the total contents of the tetraalkoxysilane, the compound I, and the silica particles and / or zirconia particles in terms of SiO2 and / or ZrO2. The silica film-coated glass substrate of the present invention has excellent alkali resistance and abrasion resistance. Although the details of the reason for this are not clear, it is presumed that it is due to the following reasons.

[0013] The silica film-forming composition of the present invention has a tetraalkoxysilane content in terms of SiO2 within a predetermined range, which is presumably why the hardness of the silica film is improved and a glass substrate with a silica film having excellent abrasion resistance is obtained. Furthermore, the silica film-forming composition of the present invention has a higher content of compound I (SiO2 equivalent) compared to the composition in Patent Document 1. Thus, when the content of compound I in the silica film-forming composition is high, a silica film containing many carbon-carbon atom bonds derived from "Q" in formula I is obtained. Carbon-carbon atom bonds are less likely to be broken by the action of alkali than silicon-oxygen atom bonds, and therefore it is presumed that this is why the alkali resistance of the silica film has improved. It is also speculated that the carbon-carbon bond derived from "Q" in formula I plays a role in blocking the micropores formed in the silica film, thereby inhibiting the penetration of ions and improving the alkali resistance of the silica film. The micropores are formed by the evaporation of residual solvents and hydrolysis-condensation reactions. The silica film-coated glass substrate of the present invention also has excellent saltwater resistance. Although the details of the reason for this are not clear, it is presumed to be the same as the reason for the excellent alkali resistance described above.

[0014] 1 is a cross-sectional view schematically showing an example of a silica-coated glass substrate of the present invention. The silica-coated glass substrate 1A has a glass substrate 10 and a silica film 20 formed on one surface of the glass substrate 10. In the example of FIG. 1, the silica film 20 is formed over the entire surface of one of the glass substrates 10, but this is not limited thereto, and the silica film 20 may be formed over only a partial region of the glass substrate 10. In the example of FIG. 1, the silica film 20 is formed on only one surface of the glass substrate 10, but the present invention is not limited to this, and the silica film 20 may be formed on both surfaces of the glass substrate 10. Each member of the silica film-coated glass substrate 1A will be described below.

[0015] [Glass substrate] The glass substrate 10 is not particularly limited, and examples thereof include soda lime glass, aluminosilicate glass, lithium glass, and borosilicate glass. The glass substrate 10 may be chemically strengthened glass. The glass substrate 10 may be a glass plate having a smooth surface formed by a float method or the like, a figured glass plate having an uneven surface, or a glass plate having a curved surface. The thickness of the glass substrate 10 is appropriately selected depending on the application and is not particularly limited, but is preferably 0.5 mm to 20 mm.

[0016] [Silica film] The silica film 20 is formed using a silica film-forming composition described below, and includes at least one selected from the group consisting of hydrolyzable compounds, their hydrolysates, and their hydrolyzed condensates, and at least one selected from the group consisting of silica particles and zirconia particles.

[0017] The thickness of the silica film 20 is preferably 10 nm to 1000 nm, more preferably 20 nm to 500 nm, and particularly preferably 30 nm to 200 nm, in terms of achieving better effects of the present invention. The thickness of the silica film 20 is measured by the method described in the Examples section below.

[0018] Specific examples of uses of the silica film 20 include an anti-glare film, a low-reflection film, and a protective film (for example, a scratch-resistant film, an alkali barrier film, a film to prevent tarnish on glass, and an anti-fouling film).

[0019] <Silica film-forming composition> The composition for forming a silica film contains at least one selected from the group consisting of hydrolyzable compounds, their hydrolysates, and their hydrolyzed condensates (hereinafter simply referred to as "hydrolyzable compounds"), and at least one selected from the group consisting of silica particles and zirconia particles. The hydrolyzable compound includes only a tetraalkoxysilane, Compound I, an optionally used fluoroalkylsilane having a hydrolyzable group, and an optionally used zirconium compound having a hydrolyzable group.

[0020] (Hydrolyzable compounds) Specific examples of tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, and tetrabutoxysilane. The tetraalkoxysilanes may be used alone or in combination of two or more.

[0021] 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

[0022] 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 monovalent hydrocarbon group preferably has 1 to 10 carbon atoms, and more preferably has 1 to 6 carbon atoms. The monovalent hydrocarbon group is one having -O-, -S-, -C(O)- and -N(R 1 )-. R 1 is a hydrogen atom or a monovalent hydrocarbon group. In formula I, when there are two or more R's, the two or more R's may be the same or different.

[0023] In formula I, L is a hydrolyzable group. A hydrolyzable group is a reactive group that undergoes decomposition and condensation reactions when it comes into contact with water. Specific examples of the hydrolyzable group include an alkoxy group, an acyloxy group, a ketoxime group, an alkenyloxy group, an amino group, an aminoxy group, an amide group, an isocyanate group, a halogen atom, etc. Among these, from the viewpoint of the balance between the stability of Compound I and the ease of hydrolysis, an alkoxy group, an isocyanate group, and a halogen atom (particularly, a chlorine atom) are preferred. The alkoxy group is preferably an alkoxy group having 1 to 3 carbon atoms, and a methoxy group or an ethoxy group is particularly preferred. In formula I, two or more L's may be the same or different.

[0024] 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, and an arylene group, and the alkylene group is preferred. The alkylene group may be linear, branched, or cyclic. Divalent hydrocarbon groups are those with -O-, -S-, -C(O)- and -N(R 2 )-. R 2 is a hydrogen atom or a monovalent hydrocarbon group.

[0025] p is an integer of 1 to 3, and is preferably 2 or 3, with 3 being particularly preferred, in terms of reaction rate.

[0026] Compound I may be used alone or in combination of two or more.

[0027] The fluoroalkylsilane having a hydrolyzable group is a component that is optionally used as a hydrolyzable compound. When the fluoroalkylsilane having a hydrolyzable group is used, the abrasion resistance of the silica film-coated glass substrate is further improved.

[0028] The fluoroalkylsilane having a hydrolyzable group is preferably a compound represented by formula II, since this provides a more excellent effect of the present invention. R F -Q 10 -Si(L 10 ) p1 R 10 3-p1 Formula II

[0029] In formula II, R F is a fluoroalkyl group, preferably a perfluoroalkyl group. The fluoroalkyl group may be linear, branched, or cyclic. The fluoroalkyl group preferably has 1 to 8 carbon atoms, and particularly preferably has 4 to 8 carbon atoms.

[0030] In formula II, Q 10 is a divalent linking group. Specific examples of the divalent linking group include -O-, -S-, -C(O)- and -N(R 11 a divalent hydrocarbon group optionally having one or more groups selected from the group consisting of —O—, —S—, —C(O)O—, —C(O)—, —C(O)—N(R 12 )-, and groups formed by combining two or more of these groups. 11 and R 12 are each independently a hydrogen atom or a monovalent hydrocarbon group. The definition of the monovalent hydrocarbon group is the same as that of R in formula I above. The preferred embodiments of the divalent hydrocarbon group are the same as those of Q in the above formula I. However, the divalent hydrocarbon group preferably has 1 to 6 carbon atoms, and particularly preferably 2 to 6 carbon atoms. Among these, the divalent linking group is preferably a divalent hydrocarbon group, more preferably an ethylene group.

[0031] In formula II, L 10 is a hydrolyzable group. The definition of the hydrolyzable group is the same as that of L in formula I above. In formula II, L 10If there are two or more, there are two or more L 10 may be the same or different.

[0032] In formula II, R 10 is a hydrogen atom or a monovalent hydrocarbon group. The definition of the monovalent hydrocarbon group is the same as that of R in Formula I above. In formula II, R 10 If there are two or more, there are two or more R 10 may be the same or different.

[0033] p1 is an integer of 1 to 3, and is preferably 2 or 3, with 3 being particularly preferred, in terms of reaction rate.

[0034] The fluoroalkylsilane having a hydrolyzable group may be used alone or in combination of two or more kinds.

[0035] The zirconium compound having a hydrolyzable group is a component that is optionally used as a hydrolyzable compound. Use of the zirconium compound having a hydrolyzable group further improves the alkali resistance of the silica film-coated glass substrate. Specific examples of zirconium compounds having a hydrolyzable group include zirconium tetra-normal propoxide, zirconium octylate compounds, and zirconium stearate. The zirconium compounds having a hydrolyzable group may be used alone or in combination of two or more.

[0036] The hydrolysate of a hydrolyzable compound refers to a compound obtained by hydrolyzing the hydrolyzable groups in the hydrolyzable compound. The hydrolysate may be one in which all of the hydrolyzable groups have been hydrolyzed (complete hydrolysate) or one in which only a portion of the hydrolyzable groups have been hydrolyzed (partial hydrolysate). In other words, the hydrolysate may be a complete hydrolysate, a partial hydrolysate, or a mixture thereof. Furthermore, the hydrolysis condensate of a hydrolyzable compound refers to a compound obtained by hydrolyzing the hydrolyzable groups in the hydrolyzable compound and condensing the resulting hydrolyzate. The hydrolysis condensate may be one in which all hydrolyzable groups are hydrolyzed and all of the hydrolyzates are condensed (complete hydrolysis condensate), or one in which some of the hydrolyzable groups are hydrolyzed and some of the hydrolyzates are condensed (partial hydrolysis condensate). In other words, the hydrolysis condensate may be a complete hydrolysis condensate, a partial hydrolysis condensate, or a mixture thereof. The hydrolysis condensate may also be a hydrolysis condensate obtained by condensing the hydrolyzates of two or more compounds among the hydrolyzable compounds.

[0037] (silica particles, zirconia particles) The silica particles are particles containing silica (SiO2), and the zirconia particles are particles containing zirconia (ZrO2). Specific examples of the shape of silica particles and zirconia particles include spherical, elliptical, needle-like, plate-like, rod-like, conical, cylindrical, cubic, rectangular, diamond-like, star-like, and irregular shapes. The silica particles and zirconia particles may be solid particles, hollow particles, or porous particles. "Solid particles" refer to particles that do not have cavities inside. "Hollow particles" refer to particles that have cavities inside. "Porous particles" refer to particles that have multiple pores on the surface. The silica particles and zirconia particles may exist in an independent state, or may be linked in a chain form, or may be aggregated.

[0038] The average agglomerated particle size of the silica particles and zirconia particles is preferably 5 nm to 100 nm, particularly preferably 5 nm to 50 nm, in terms of achieving better effects of the present invention. The average agglomerated particle size of silica particles and zirconia particles refers to the cumulative 50% diameter (D50) on a volume basis measured using a laser diffraction particle size distribution measuring device.

[0039] As the silica particles, commercially available products may be used, for example, Snowtex series manufactured by Nissan Chemical Industries, Ltd. The silica particles may be used alone or in combination of two or more types. As the zirconia particles, commercially available products may be used, for example, the Bailar series manufactured by Taki Chemical Industry Co., Ltd. The zirconia particles may be used alone or in combination of two or more types. There are no particular restrictions on whether to use silica particles or zirconia particles, but when zirconia particles are used, the high sinterability of the zirconia particles can solve the problem of cracks that tend to occur when a silica-coated glass substrate is heat-treated at a higher temperature, and the silica film can be made more dense, making it easier to achieve high durability in the silica-coated substrate.

[0040] (metal catalyst) The silica film-forming composition preferably contains a metal catalyst in order to promote the hydrolysis and condensation of the hydrolyzable compound. Specific examples of metal catalysts include aluminum chelate compounds such as aluminum acetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum-di-n-butoxide-monoethylacetoacetate, aluminum-di-isopropoxide-monomethylacetoacetate, and diisopropoxyaluminum ethyl acetate; titanium chelate compounds such as titanium acetylacetonate and titanium tetraacetylacetonate; copper chelate compounds such as copper acetylacetonate; cerium chelate compounds such as cerium acetylacetonate; chromium chelate compounds such as chromium acetylacetonate; 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 chelate compounds such as nickel acetylacetonate; zinc chelate compounds such as zinc acetylacetonate; zirconium chelate compounds such as zirconium acetylacetonate; and organotin compounds such as dialkyltins. Among these, 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 catalysts may be used alone or in combination of two or more.

[0041] (liquid medium) The silica film-forming composition preferably contains a liquid medium, which is preferably a solvent that dissolves or disperses the hydrolyzable compound and disperses the silica particles and zirconia particles in the composition.

[0042] 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, as well as water.

[0043] Specific examples of alcohols include methanol, ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, and diacetone alcohol. Specific examples of 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 esters include methyl acetate and ethyl acetate. A specific example of the glycol ethers is ethylene glycol monoalkyl ether. Specific examples of the nitrogen-containing compound include N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone. A specific example of the sulfur-containing compound is dimethyl sulfoxide.

[0044] The liquid medium may be used alone or in combination of two or more kinds. From the viewpoint of hydrolysis of the hydrolyzable compound, the liquid medium preferably contains only water or is a mixed solvent of water and an organic solvent. When a mixed solvent of water and an organic solvent is used, the organic solvent is preferably an alcohol.

[0045] (Other ingredients) The silica film-forming composition may contain other components in addition to those described above, such as silicone oil, surfactant, pH adjuster (e.g., acid, alkali, etc.), and antifoaming agent.

[0046] (Content) In the silica film-forming composition, the content of the tetraalkoxysilane in terms of SiO2 is 2 to 35% by mass relative to the total content of the content of the tetraalkoxysilane in terms of SiO2, the content of Compound I in terms of SiO2, and the content of at least one selected from the group consisting of silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2. Furthermore, the content is preferably 5% by mass or more, more preferably 7% by mass or more, and particularly preferably 15% by mass or more, in order to provide a silica film-coated glass substrate with superior abrasion resistance, and is preferably 30% by mass or less, and particularly preferably 20% by mass or less, in order to provide a silica film-coated glass substrate with superior alkali resistance and saltwater resistance.

[0047] In the silica film-forming composition, the content of compound I in terms of SiO2 is 15 to 88% by mass relative to the total content of the content of tetraalkoxysilane in terms of SiO2, the content of compound I in terms of SiO2, and the content of at least one selected from the group consisting of silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2. From the viewpoint of providing a silica film-coated glass substrate with better alkali resistance and salt water resistance, the content is preferably 20% by mass or more, more preferably 25% by mass or more, and particularly preferably 30% by mass or more, and from the viewpoint of providing a silica film-coated glass substrate with better abrasion resistance, the content is preferably 60% by mass or less, more preferably 55% by mass or less, and particularly preferably 50% by mass or less.

[0048] In the silica film-forming composition, the content of at least one selected from the group consisting of silica particles and zirconia particles, expressed in terms of SiO2, ZrO2, or SiO2 and ZrO2, is 10 to 60 mass% based on the total content of the tetraalkoxysilane content expressed in terms of SiO2, the content of Compound I expressed in terms of SiO2, and the content of at least one selected from the group consisting of silica particles and zirconia particles, expressed in terms of SiO2, ZrO2, or SiO2 and ZrO2. From the viewpoint of providing a silica film-coated glass substrate with superior abrasion resistance, the content is preferably 30 mass% or more, more preferably 32 mass% or more, and particularly preferably 35 mass% or more. From the viewpoint of providing a silica film-coated glass substrate with superior alkali resistance and saltwater resistance, the content is preferably 50 mass% or less, more preferably 48 mass% or less, and particularly preferably 45 mass% or less.

[0049] When the silica film-forming composition contains a fluoroalkylsilane having a hydrolyzable group, the content of the fluoroalkylsilane having a hydrolyzable group in the silica film-forming composition, expressed in SiO2 equivalent, relative to the total content of the content of the tetraalkoxysilane in SiO2 equivalent, the content of compound I in SiO2 equivalent, the content of at least one selected from the group consisting of silica particles and zirconia particles in SiO2 equivalent, ZrO2 equivalent, or SiO2 and ZrO2 equivalent, and the content of the fluoroalkylsilane having a hydrolyzable group in SiO2 equivalent, is preferably 0.1 mass% or more, and more preferably 0.5 mass% or more, in order to provide a glass substrate with a silica film having better abrasion resistance, and is preferably 5 mass% or less, and more preferably 3 mass% or less, in order to provide a glass substrate with a silica film having better alkali resistance and salt water resistance.

[0050] When the silica film-forming composition contains a zirconium compound having a hydrolyzable group, the content of the zirconium compound having a hydrolyzable group in the silica film-forming composition, expressed in terms of ZrO2, relative to the total content of the content of the tetraalkoxysilane expressed in terms of SiO2, the content of compound I expressed in terms of SiO2, the content of at least one selected from the group consisting of silica particles and zirconia particles expressed in terms of SiO2, ZrO2, or SiO2 and ZrO2, and the content of the zirconium compound having a hydrolyzable group expressed in terms of ZrO2, is preferably 0.1 mass% or more, and more preferably 0.3 mass% or more, in order to provide a glass substrate with a silica film having better alkali resistance and saltwater resistance, and is preferably 6 mass% or less, and more preferably 4 mass% or less, in order to provide a glass substrate with a silica film having better abrasion resistance.

[0051] When the silica film-forming composition contains a metal catalyst, the content of the metal catalyst is preferably 0.01 to 5 mass%, and particularly preferably 0.1 to 3 mass%, based on the total content of the tetraalkoxysilane content in terms of SiO2, the compound I content in terms of SiO2, the content of at least one selected from the group consisting of silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2, and the content of the optionally used fluoroalkylsilane having a hydrolyzable group in terms of SiO2.

[0052] When the silica film-forming composition contains the other components described above, the content of the other components is preferably 0.1 to 3 mass%, and particularly preferably 0.5 to 2 mass%, relative to the total content of the tetraalkoxysilane content in SiO2 equivalent, the compound I content in SiO2 equivalent, the content of at least one selected from the group consisting of silica particles and zirconia particles in SiO2 equivalent, ZrO2 equivalent, or SiO2 and ZrO2 equivalent, and the content of the optionally used fluoroalkylsilane having a hydrolyzable group in SiO2 equivalent.

[0053] When the silica film-forming composition contains a liquid medium, the content of the liquid medium is preferably 86.0 to 99.5 mass %, particularly preferably 88.5 to 99.0 mass %, based on the total mass of the silica film-forming composition.

[0054] (Preparation method) The silica film-forming composition can be produced by mixing at least one selected from the group consisting of hydrolyzable compounds, their hydrolysates, and their hydrolysis condensates with at least one selected from the group consisting of silica particles and zirconia particles, and optional components (e.g., metal catalyst, liquid medium).

[0055] [Application] The uses of the silica film-coated glass substrate 1A are not particularly limited, and examples thereof include transparent parts for vehicles (headlight covers, side mirrors, front transparent substrates, side transparent substrates, rear transparent substrates, instrument panel surfaces, etc.), meters, architectural windows, show windows, displays (notebook computers, monitors, LCDs, PDPs, ELDs, CRTs, PDAs, etc.), LCD color filters, touch panel substrates, pickup lenses, optical lenses, eyeglass lenses, camera parts, video parts, CCD cover substrates, optical fiber end faces, projector parts, copier parts, transparent substrates for solar cells (cover glass, etc.), mobile phone windows, backlight unit parts (light guide plates, cold cathode fluorescent lamps, etc.), liquid crystal brightness enhancement films, organic EL light-emitting element parts, inorganic EL light-emitting element parts, phosphor light-emitting element parts, optical filters, end faces of optical parts, lighting lamps, lighting fixture covers, and amplified laser light sources.

[0056] [Method for manufacturing a silica film-coated glass substrate] The method for producing the silica film-coated glass substrate 1A includes applying the above-mentioned silica film-forming composition onto the glass substrate 10 and drying it as necessary to form the silica film 20 on the glass substrate 10.

[0057] Examples of the coating method include wet coating methods such as spin coating, spray coating, dip coating, die coating, curtain coating, screen coating, inkjet coating, flow coating, gravure coating, bar coating, flexo coating, slit coating, and roll coating.

[0058] Drying may be carried out by heating, or by natural drying or air drying without heating. The drying temperature is preferably 50° C. or higher, particularly preferably 100° C. or higher, in order to obtain a silica film with excellent hardness. The drying time may be appropriately set depending on the drying temperature, the size of the glass substrate, etc., but is preferably 5 minutes or more, and particularly preferably 10 minutes or more.

[0059] Other Aspects FIG. 1 shows an example in which the glass substrate 10 and the silica film 20 are in contact with each other, but this is not limited thereto, and the glass substrate with a silica film of the present invention may have another layer between the glass substrate 10 and the silica film 20, as shown in FIG.

[0060] 2 is a cross-sectional view schematically illustrating an example of a silica-coated glass substrate of the present invention. The silica-coated glass substrate 1B in this embodiment includes a glass substrate 10, a heat ray reflective film 30A formed on one surface of the glass substrate 10, and a silica film 20 formed on the surface of the heat ray reflective film 30A opposite to the glass substrate 10. The heat ray reflective film 30A has a first dielectric layer 31, a first silver-containing layer 32, and a second dielectric layer 33 in this order from the glass substrate 10 side. In the example of Figure 2, the heat ray reflecting film 30A is formed over the entire surface of one of the glass substrates 10, but this is not limited to this, and the heat ray reflecting film 30A may be formed over only a partial area of ​​the glass substrate 10.

[0061] Each member of the silica film-coated glass substrate 1B will be described below. The silica coated glass substrate 1B is similar to the silica coated glass substrate 1A described above except that it has a heat ray reflective film 30A, and therefore the description of the members described for the silica coated glass substrate 1A will be omitted.

[0062] <Heat ray reflective film> In this embodiment, the heat ray reflecting film 30A is disposed between the glass substrate 10 and the silica film 20. The heat ray reflecting film 30A can improve the heat shielding properties of the silica film-coated glass substrate 1B. The heat ray reflective film 30A has a first dielectric layer 31, a first silver-containing layer 32, and a second dielectric layer 33 in this order along the thickness direction. The thickness of the heat ray reflecting film 30A is preferably 15 nm to 565 nm, more preferably 25 nm to 460 nm, and particularly preferably 30 nm to 390 nm, in order to provide the silica coated glass substrate 1B with better heat shielding properties and design properties. The thickness of the heat ray reflective film 30A can be calculated by adding up the thicknesses of the layers that make up the heat ray reflective film 30A. The thickness of each layer that makes up the heat ray reflective film 30A can also be determined by the method described in the Examples section below.

[0063] (Silver-containing layer) The first silver-containing layer 32 is a layer containing silver, and the heat shielding properties of the silica film-coated glass substrate 1B can be further improved by the action of silver. Here, the silver contained in the first silver-containing layer 32 is susceptible to corrosion when exposed to the outside air, but the silica film-coated glass substrate 1B can suppress the corrosion of silver because it has the silica film 20. This allows the silica film-coated glass substrate 1B to maintain excellent heat-shielding performance.

[0064] The first silver-containing layer 32 may contain metals other than silver (hereinafter also referred to as "other metals"), such as at least one metal selected from the group consisting of palladium, gold, chromium, cobalt, nickel, copper, and titanium. The other metals may be used alone or in combination of two or more.

[0065] The content of silver contained in the first silver-containing layer 32 is preferably 100 mass %. However, when the first silver-containing layer 32 contains other metals, the silver content is preferably 50% by mass or more, more preferably 65% ​​by mass or more, and particularly preferably 80% by mass or more, based on the total mass of the first silver-containing layer 32, from the viewpoint of heat shielding properties. When the first silver-containing layer 32 contains other metals, the silver content in the first silver-containing layer 32 is preferably 99% by mass or less, and particularly preferably 97% by mass or less, based on the total mass of the first silver-containing layer 32. The content of the other metals is preferably 1 to 30% by mass, and particularly preferably 1 to 20% by mass, based on the total mass of the first silver-containing layer 32.

[0066] The thickness of the first silver-containing layer 32 is preferably 5 nm to 30 nm, particularly preferably 7 nm to 25 nm, from the viewpoint of heat insulation.

[0067] In the example of Figure 2, the heat ray reflective film has one silver-containing layer, but the number of silver-containing layers is not limited to this, and the heat ray reflective film may have two or more silver-containing layers. When the heat ray reflective film has a plurality of silver-containing layers, the total thickness of the silver-containing layers is preferably 10 nm to 60 nm, particularly preferably 14 nm to 50 nm, from the viewpoint of the heat shielding property and design of the silica film-coated glass substrate.

[0068] (dielectric layer) The silver-containing layer is preferably sandwiched between the first dielectric layer 31 and the second dielectric layer 33. These dielectric layers have the function of suppressing reflectance or improving the film quality of the silver-containing layer. The material constituting each dielectric layer may be a dielectric containing at least one metal selected from the group consisting of metal oxides, nitrides, and oxynitrides, including zinc, tin, titanium, silicon, aluminum, chromium, nickel, niobium, and alloys thereof. The material constituting each dielectric layer may be doped with an additive, such as at least one selected from the group consisting of oxides, nitrides, and oxynitrides of tin, aluminum, chromium, titanium, silicon, boron, magnesium, zirconium, and gallium. Among these, nitrides and oxides are preferred as materials for forming each dielectric layer, with silicon nitride (SiN) and zinc oxide (ZnO) being particularly preferred.

[0069] From the viewpoint of adjusting optical characteristics, the thickness of each of the first dielectric layer 31 and the second dielectric layer 33 is preferably 5 nm to 120 nm, and particularly preferably 10 nm to 100 nm.

[0070] In the example of Figure 2, the heat ray reflective film has two dielectric layers, but the number of dielectric layers is not limited to this, and the heat ray reflective film may have three or more dielectric layers. When the heat ray reflective film has a plurality of dielectric layers, the total thickness of the dielectric layers is preferably 10 nm to 400 nm, particularly preferably 20 nm to 350 nm, from the viewpoint of adjusting optical properties.

[0071] (other layers) In the example of FIG. 2, the heat ray reflective film has a silver-containing layer and a dielectric layer, but the heat ray reflective film may have layers other than these (hereinafter also referred to as "other layers"). A specific example of the other layer is a barrier layer. The barrier layer can be provided to stabilize the silver-containing layer or to suppress oxidation of the silver-containing layer when forming the dielectric layer. In this case, the barrier layer is disposed between the dielectric layer and the silver-containing layer. Specific examples of materials constituting the barrier layer include nickel-chromium alloys, titanium, zinc-aluminum alloys, and oxides thereof, with nickel-chromium alloys being preferred among them. The heat ray reflective film may have only one barrier layer, or may have two or more barrier layers. The thickness of the barrier layer is preferably 0.1 nm to 15 nm, particularly preferably 0.5 nm to 10 nm.

[0072] (Variation) Although FIG. 2 shows an embodiment in which the heat ray reflective film has only one silver-containing layer, the present invention is not limited to this, and the heat ray reflective film may have two or more silver-containing layers. A specific example of a heat ray reflective film having two or more silver-containing layers is shown in FIG. 3 is a cross-sectional view schematically illustrating an example of a silica-coated glass substrate of the present invention. The silica-coated glass substrate 1C in this embodiment includes a glass substrate 10, a heat ray reflective film 30B formed on one surface of the glass substrate 10, and a silica film 20 formed on the surface of the heat ray reflective film 30B opposite to the glass substrate 10. The heat ray reflective film 30B has, in order from the glass substrate 10 side, a first dielectric layer 31, a first silver-containing layer 32, a second dielectric layer 33, a second silver-containing layer 34, and a third dielectric layer 35. In the example of Figure 3, the heat ray reflecting film 30B is formed over the entire surface of one of the glass substrates 10, but this is not limited to this, and the heat ray reflecting film 30B may be formed over only a partial area of ​​the glass substrate 10.

[0073] The silica-coated glass substrate 1C is similar to the silica-coated glass substrate 1B described above except that it has a heat-reflecting film 30B instead of the heat-reflecting film 30A, and therefore the components described for the silica-coated glass substrate 1B will not be described here.

[0074] The second silver-containing layer 34 in the heat ray reflective film 30B is the same as the first silver-containing layer 32 in the heat ray reflective film 30A, except for the position where it is formed. The third dielectric layer 35 in the heat ray reflecting film 30B is similar to the first dielectric layer 31 and the second dielectric layer 33 in the heat ray reflecting film 30A, except that it is formed at a different position.

[0075] In the example of FIG. 3, the heat ray reflective film has a silver-containing layer and a dielectric layer, but it may also have other layers such as a barrier layer, as in FIG.

[0076] (thickness ratio) When the heat ray reflective film has a silver-containing layer and an upper layer consisting of all layers disposed closer to the silica film than the silver-containing layer, the ratio of the thickness of the silica film to the thickness of the upper layer (thickness of the silica film / thickness of the upper layer) is preferably 0.5 to 30, more preferably 0.7 to 20, and particularly preferably 1 to 10. When the thickness ratio is 30 or less, the emissivity of the silica film-coated glass substrate can be reduced, thereby further improving the heat shielding performance. When the thickness ratio is 0.5 or more, the alkali resistance and abrasion resistance are more excellent. Here, the upper layer is a general term for a layer disposed closer to the silica film than the silver-containing layer, and corresponds to the second dielectric layer 33 in the example of Fig. 2. In addition, in the example of Fig. 3, the upper layer corresponds to the third dielectric layer 35. When there are multiple layers located closer to the silica film than the silver-containing layer, the entirety of the multiple layers is the upper layer. Therefore, the thickness of the upper layer means the thickness of only one layer when the upper layer consists of only one layer, and means the total thickness of each layer when the upper layer consists of two or more layers.

[0077] (physical properties, etc.) The silica film-coated glass substrate 1B and the silica film-coated glass substrate 1C were free from scratches after the abrasion test described below. Abrasion test method The cotton cloth is rubbed onto a rubbing tester contact (HEIDON, TYPE30S, contact area: 2cm x 2cm = 4cm 2 ) and attach the contacts to 19.6 x 10 -2 The surface of the silica film on the silica-coated glass substrate is subjected to horizontal reciprocating motion 5,000 times at a pressure of 100 MPa. The area rubbed with cotton cloth is irradiated with transmitted light and visually inspected for scratches.

[0078] The silica film-coated glass substrate 1B and the silica film-coated glass substrate 1C preferably have a haze value of 0.4% or less, more preferably 0.3% or less, as measured in accordance with JIS K7136:2000 after the alkali test described below, and it is particularly preferable that no cloudiness is observed visually. Alkali test method The silica-coated glass substrate is immersed in a 0.1N sodium hydroxide solution adjusted to 23±2°C for 6 hours, then rinsed with pure water and dried with an air blower. After drying, the test area is irradiated with light and the degree of cloudiness is visually confirmed. Furthermore, the haze value is measured according to JISK7136:2000.

[0079] The emissivity of the silica coated glass substrate 1B and the silica coated glass substrate 1C is preferably 0.01 to 0.35, more preferably 0.01 to 0.25, and particularly preferably 0.01 to 0.15, in order to improve the heat shielding performance of the silica coated glass substrate. The method for measuring the emissivity is as described in the Examples section below.

[0080] <Method of manufacturing a silica film-coated glass substrate> A method for manufacturing a silica-coated glass substrate 1B includes forming each layer constituting the heat ray reflective film 30A in the stated order on a glass substrate 10, then applying the above-mentioned silica film-forming composition to the heat ray reflective film 30A and drying it as necessary to form the heat ray reflective film 30A and silica film 20 in that order on the glass substrate 10. The method for forming each layer constituting the heat ray reflective film 30A is not particularly limited, and examples thereof include physical vapor deposition (e.g., vacuum vapor deposition, ion plating, sputtering), chemical vapor deposition (e.g., thermal CVD, plasma CVD, photo CVD), ion beam sputtering, etc. The method for producing the silica-coated glass substrate 1C is the same as the method for producing the silica-coated glass substrate 1B, except that the layers constituting the heat ray reflective film 30B are formed in the order shown. [Example]

[0081] The present invention will be described in detail below with reference to examples. Examples 1 to 6 and 10 are working examples, and Examples 7 to 9 are comparative examples. However, the present invention is not limited to these examples.

[0082] [Measuring the thickness of the silica film] A silica film was formed on one side of a soda-lime glass plate under the conditions described in each example below. Black vinyl tape was attached to the other side of the soda-lime glass plate, on which the silica film was not formed, and the reflectance of the silica film was measured in the wavelength range of 300 nm to 780 nm using a spectrophotometer (U-4100 manufactured by Hitachi High-Technologies Corporation). The lowest reflectance obtained (bottom reflectance: Rmin) and the refractive index n of the uncoated soda lime glass plate s The refractive index n was calculated from the following formula (1), and then the thickness d of the silica film was calculated from the obtained refractive index n and the wavelength λ (nm) at the bottom reflectance (Rmin) using the following formula (2). Rmin=(nn s ) 2 / (n+n s ) 2 ···(1) n×d=λ / 4 (2)

[0083] [Emissivity measurement] The emissivity of the silica film-coated glass substrate of each example was measured using an emissivity meter (D and S AERD, manufactured by Kyoto Electronics Manufacturing Co., Ltd.) The results are shown in Table 1.

[0084] [Alkali resistance evaluation test] The silica film-attached glass substrate of each example was immersed in a 0.1N aqueous sodium hydroxide solution adjusted to 23±2° C. for 6 hours, then washed with pure water and dried by air blowing. After drying, the test area was irradiated with light, and the degree of cloudiness was visually confirmed, and the alkali resistance was evaluated according to the following criteria. Furthermore, the haze value was measured using Haze Guard i (manufactured by BYK-Gardner). The results are shown in Table 1. AA: No cloudiness is observed. A: Some cloudiness is observed. B: Cloudiness is observed over the entire surface.

[0085] [Saltwater resistance evaluation test] The silica film-attached glass substrate of each example was immersed in a 5% aqueous sodium chloride solution adjusted to 50±2° C. for 24 hours, then washed with pure water and dried by air blowing. The dried silica film-coated glass substrate was visually observed and evaluated for saltwater resistance according to the following criteria. The results are shown in Table 1. A: No change in appearance B: Appearance change (light spots and unevenness)

[0086] [Wear resistance evaluation test] The cotton cloth is rubbed onto a rubbing tester contact (HEIDON, TYPE30S, contact area: 2cm x 2cm = 4cm 2 ) and attach the contacts to 19.6 x 10 -2 The surface of the silica film on the silica-coated glass substrate of each example was subjected to horizontal reciprocating motion at a pressure of 100 MPa. After 5,000 reciprocating movements, the area rubbed with the cotton cloth was irradiated with light, and the presence or absence of scratches was confirmed using the transmitted light. The abrasion resistance was evaluated according to the following criteria. The results are shown in Table 1. A: No scratches B: Scratches have occurred

[0087] [Preparation of Silica Film-Forming Composition A] While stirring 73.67 g of denatured ethanol (manufactured by Japan Alcohol Sales Co., Ltd., trade name "Solmix AP-11"), 23.6 g of ion-exchanged water and 0.01 g of aluminum acetylacetonate were added, and the mixture was stirred for 5 minutes. To this was added 0.17 g of tetraethoxysilane, 0.81 g of bis(trimethoxysilyl)hexane, and 1.75 g of silica particle dispersion (manufactured by Nissan Chemical Industries, Ltd., product name "Snowtex OS", SiO2 equivalent: 20% by mass), and the mixture was stirred at room temperature for 30 minutes to prepare silica film-forming composition A. In the silica film-forming composition A, the contents of tetraethoxysilane, bis(trimethoxysilyl)hexane, and silica particles, calculated as SiO2, were 7 mass%, 43 mass%, and 50 mass%, respectively, relative to the total contents of tetraethoxysilane, bis(trimethoxysilyl)hexane, and silica particles, calculated as SiO2.

[0088] [Preparation of Silica Film-Forming Compositions B to F] Compositions B to F for forming silica films were obtained in the same manner as in the preparation of composition A for forming silica films, except that the amounts of each component used were adjusted so that the contents of tetraethoxysilane, bis(trimethoxysilyl)hexane and silica particles in terms of SiO2 relative to the total contents of tetraethoxysilane, bis(trimethoxysilyl)hexane and silica particles in terms of SiO2 were the values ​​shown in Table 1. [Preparation of Silica Film-Forming Composition G] While stirring 73.67 g of denatured ethanol (manufactured by Japan Alcohol Sales Co., Ltd., trade name "Solmix AP-11"), 23.6 g of ion-exchanged water and 0.01 g of aluminum acetylacetonate were added, and the mixture was stirred for 5 minutes. To this was added 0.84 g of tetraethoxysilane, 0.28 g of bis(trimethoxysilyl)hexane, and 1.75 g of zirconia particle dispersion (manufactured by Taki Chemical Co., Ltd., product name "Baylal Zr-C20", ZrO2 equivalent: 20% by mass), and the mixture was stirred at room temperature for 30 minutes to produce silica film-forming composition G. In silica film-forming composition G, the content of tetraethoxysilane in terms of SiO2, the content of bis(trimethoxysilyl)hexane in terms of SiO2, and the content of zirconia particles in terms of ZrO2 were 35 mass%, 15 mass%, and 50 mass%, respectively, relative to the total content of the content of tetraethoxysilane in terms of SiO2, the content of bis(trimethoxysilyl)hexane in terms of SiO2, and the content of zirconia particles in terms of ZrO2.

[0089] [Preparation of glass substrate with heat reflective film] A soda-lime glass plate (AGC Corporation (FL5)) was used as the glass substrate. A heat-reflecting film was deposited on one main surface of the soda-lime glass plate using an in-line sputtering system in the following order: SiN layer (30 nm), NiCr layer (2 nm), Ag layer (12 nm), NiCr layer (2 nm), SiN layer (88 nm), NiCr layer (1 nm), Ag layer (14 nm), NiCr layer (1 nm), and SiN layer (39 nm). This resulted in a glass substrate with a heat-reflecting film. The values ​​in parentheses indicate the layer thickness. The thickness of each layer was calculated by proportional conversion based on the thickness when deposited at a predetermined input power. Specifically, the SiN layer was formed by AC sputtering in an atmosphere containing argon and nitrogen, using a sputtering target primarily composed of silicon. The NiCr layer was formed by DC sputtering in an argon atmosphere, using a sputtering target primarily composed of a nickel-chromium alloy. The Ag layer was formed by DC sputtering in an argon atmosphere, using a sputtering target primarily composed of silver. The SiN layer is the dielectric layer, the NiCr layer is the barrier layer, and the Ag layer is the silver-containing layer.

[0090] [Example 1] The above-mentioned glass substrate with a heat ray reflective film (size: 100 mm×100 mm) was washed with pure water and then air-dried. After air drying, the above-mentioned silica film-forming composition A was dropped onto the surface of the heat ray-reflecting film of the heat ray-reflecting film-coated glass, and a coated glass substrate on which a coating of the silica film-forming composition A was formed was produced using a spin coating method (spin-off rotation speed: 300 rpm). The glass substrate with the coating film was placed in a hot air furnace with the temperature adjusted to 130°C, heated for 10 minutes to harden the coating film, and then cooled at room temperature to obtain the glass substrate with the silica film of Example 1.

[0091] [Examples 2-5 and 7-10] Glass substrates with silica films of Examples 2 to 5 and Examples 7 to 10 were prepared in the same manner as in Example 1, except that the silica film-forming composition shown in Table 1 was used instead of silica film-forming composition A, and the coating conditions were adjusted so that the thickness of the silica film would be the value shown in Table 1.

[0092] [Example 6] A silica film-coated glass substrate of Example 6 was produced in the same manner as in Example 1, except that a soda lime glass plate was used instead of the heat ray reflective film-coated glass substrate.

[0093] [Evaluation results] The above-mentioned various evaluations were carried out using the silica film-attached glass substrates of Examples 1 to 10. The results are shown in Table 1. In Table 1, "content (mass %) in terms of SiO2" means the content of tetraethoxysilane in terms of SiO2, the content of bis(trimethoxysilyl)hexane in terms of SiO2, and the content of at least one kind selected from the group consisting of silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2 relative to the total content of the content of tetraethoxysilane in terms of SiO2, the content of bis(trimethoxysilyl)hexane in terms of SiO2, and the content of at least one kind selected from the group consisting of silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2. Furthermore, "thickness of silica film / thickness of upper layer" means the ratio of the thickness of the silica film to the thickness of the upper layer (NiCr layer (1 nm) and SiN layer (39 nm) in the heat ray reflective film).

[0094] [Table 1]

[0095] As shown in Table 1, it was confirmed that by using a composition for forming a silica film in which the content of tetraalkoxysilane in terms of SiO2, the content of compound I in terms of SiO2, and the content of at least one kind selected from the group consisting of silica particles and zirconia particles in terms of SiO2, ZrO2, or SiO2 and ZrO2 are each within a specified range, a glass substrate with a silica film having excellent alkali resistance, salt water resistance, and abrasion resistance can be obtained (Examples 1 to 6, 10).

[0096] This application is based on Japanese Patent Application No. 2020-123193 filed on July 17, 2020, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0097] 1A, 1B, 1C Silica coated glass substrate 10 Glass substrate 20 Silica membrane 30A,30B Heat ray reflective film 31 first dielectric layer 32 First silver-containing layer 33 Second dielectric layer 34 Second silver-containing layer 35 Third dielectric layer

Claims

1. A silica film-coated glass substrate comprising a glass substrate and a silica film disposed on the glass substrate and formed using a silica film-forming composition, the silica film-forming composition comprises at least one selected from the group consisting of hydrolyzable compounds, their hydrolysates, and their hydrolysis condensates, and at least one selected from the group consisting of silica particles and zirconia particles; the hydrolyzable compound contains only a tetraalkoxysilane, a compound represented by formula I, an optional fluoroalkylsilane having a hydrolyzable group, and an optional zirconium compound having a hydrolyzable group; The SiO of the tetraalkoxysilane ２ The content in terms of SiO of the tetraalkoxysilane is ２ and the content in terms of SiO of the compound represented by formula I. ２ and the content of at least one SiO 2 selected from the group consisting of silica particles and zirconia particles. ２ Conversion, ZrO ２ Conversion, or SiO ２ and ZrO ２ The total content of the hydroxybenzoate and the hydroxybenzoate converted from hydroxybenzoate is 2 to 35 mass%. The SiO of the compound represented by formula I ２ The content in terms of SiO of the tetraalkoxysilane is ２ and the content in terms of SiO of the compound represented by formula I. ２ and the content of at least one SiO 2 selected from the group consisting of silica particles and zirconia particles. ２ Conversion, ZrO ２ Conversion, or SiO ２ and ZrO ２ The total content of the ... At least one kind of SiO selected from the group consisting of silica particles and zirconia particles ２ Conversion, ZrO ２ Conversion, or SiO ２ and ZrO ２ The content in terms of SiO of the tetraalkoxysilane is ２ and the content in terms of SiO of the compound represented by formula I. ２ and the content of at least one SiO 2 selected from the group consisting of silica particles and zirconia particles. ２ Conversion, ZrO ２ Conversion, or SiO ２ and ZrO ２ A glass substrate with a silica film, the content of which is 10 to 60 mass% based on the total content of the silica film and the silica content in terms of silica conversion: R ３－ｐ (L) ｐ Si-Q-Si (L) ｐ R ３－ｐ Formula I In the formula I, R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms; L is a hydrolyzable group; Q is a divalent hydrocarbon group having 2 to 6 carbon atoms; p is an integer of 1 to 3.

2. The SiO of the compound represented by formula I ２ The content in terms of SiO of the tetraalkoxysilane is ２ and the content in terms of SiO of the compound represented by formula I. ２ and the content of at least one SiO 2 selected from the group consisting of silica particles and zirconia particles. ２ Conversion, ZrO ２ Conversion, or SiO ２ and ZrO ２ 2. The glass substrate with a silica film according to claim 1, wherein the content of the silica film is 30 to 50 mass % based on the total content of the silica film and the silica-converted content.

3. The silica film-formed glass substrate according to claim 1 or 2, wherein the silica film-forming composition further contains a metal catalyst.

4. 4. The silica-coated glass substrate according to claim 1, further comprising a heat ray reflecting film between the glass substrate and the silica film.

5. the heat ray reflective film has a silver-containing layer and an upper layer consisting of all layers disposed on the silica film side of the silver-containing layer, 5. The silica-coated glass substrate according to claim 4, wherein the ratio of the thickness of the silica film to the thickness of the upper layer is 0.5 to 30.

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