Glass substrate coating agent and method for forming coating

Abstract

Coating agent for imparting high hardness, heat resistance, scratch resistance, acid resistance, chemical resistance, high stability, and the like to glass substrate, method for forming coating, and coating layer MEANS FOR SOLVING THE PROBLEM: A coating agent for a glass substrate, comprising a hydrolytic condensate of an alkoxysilane compound and water in the presence of an acid catalyst, and a solvent, wherein the mass ratio of the alkoxysilane compound to the water is 1:0.1 to 5, the weight average molecular weight of the hydrolytic condensate is 1,000 to 20,000, and the solid content concentration of the hydrolytic condensate is 0.1 to 50% by mass, and a method for forming a coating and a coating layer using the coating agent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a coating agent and a coating forming method that impart high hardness, heat resistance, scratch resistance, acid resistance, chemical resistance, high stability, etc. to a glass substrate. [Background technology]

[0002] BACKGROUND ART Various glass substrates, including architectural window glass, vehicle window glass, and the like, have been coated with various coatings for the purpose of imparting durability, heat resistance, acid resistance, chemical resistance, scratch resistance, specific functions, and the like, and depending on the application. Among these, silicate coatings in particular are widely used because they are inorganic substances like glass, can maintain transparency, and have good adhesion to glass, and various technological developments have been made into them.

[0003] For example, a coating consisting of two layers, a first layer made of a dimethyl silicone derivative dispersed in a silica matrix and a second layer made of a specific fluoroalkylsilane, is known for use on architectural window glass, vehicle window glass, mirrors, and other industrial glass, and is highly durable and improves water slippage (Patent Document 1). It is also known to form a glass coating film having weather resistance, heat resistance, etc., made of a hydrolyzate of organoalkoxysilane and activated alumina (Patent Document 2).

[0004] Furthermore, a coating agent is also known that contains inorganic fine particles such as aluminum oxide, alkoxysilane or silicon oxide fine particles, and a magnesium compound, and has excellent hydrophilic durability, high hardness, high transparency, water resistance, chemical resistance, etc. (Patent Document 3). It is also known that in order to impart highly durable antiglare and antifouling properties to glass materials, the glass materials are coated with an antiglare treatment agent consisting of a hydrolysis condensate of a tetraalkoxysilane compound and an alcohol, and further coated with a fluorine-based antireflection agent (Patent Document 4).

[0005] On the other hand, heat-resistant glass used in incinerators, lamps, heat sources, etc. is resistant to high temperatures and contains Cl and NO. x and SO x In particular, depending on the area of ​​use, there may be cases where the coating is exposed to a temperature environment of several hundred degrees or comes into contact with extremely high concentrations of corrosive substances, and therefore a coating agent that has heat resistance, scratch resistance, acid resistance, chemical resistance, high stability, etc., as well as high hardness is required. However, even if silicates or hydrolysis condensates of alkoxysilane compounds, for which various technologies have been publicly implemented, have been used, they were not designed for such extremely harsh environments, and often resulted in whitening or corrosion.

[0006] Even coating agents such as highly heat-resistant and durable alkoxysilane compounds have anti-fouling properties at room temperature, but at high temperatures of several hundred degrees, they thermally decompose and are unable to fully function (Patent Document 1). They also have anti-fouling properties due to their hydrophilic properties at room temperature, but because they are inorganic particles, it is difficult to ensure complete transparency. Furthermore, while they are advantageous in terms of heat resistance, they are weak against physical impacts due to their low binder content, and are unable to withstand temperatures of several hundred degrees (Patent Document 2). They have excellent weather resistance, but do not have the dense coating properties required, and they also lack excellent transparency (Patent Document 3).

[0007] Furthermore, even if a film is coated with an anti-glare treatment agent consisting of a hydrolysis condensate of a tetraalkoxysilane compound and an alcohol or the like, and then further coated with a fluorine-based anti-reflection agent, this configuration alone does not necessarily provide heat resistance, scratch resistance, acid resistance, chemical resistance, high stability, etc. (Patent Document 4).

[0008] In addition, it has anti-reflection (AG: Anti-Glare) and anti-fouling (AF: Anti-Fo This patent is related to the reduction of the process of continuously painting for anti-reflection. The surface is not uniform due to the coating, which impairs the transparent appearance, and there are thin areas of the coating, which results in insufficient acid resistance. In addition, the baking temperature is low, so the coating properties are not sufficiently improved (Patent Document 4). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 3961349 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-247791 [Patent Document 3] Patent No. 4562407 [Patent Document 4] Japanese Patent Application Laid-Open No. 2024-16433 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to solve the problems and issues in the prior art described above and to provide a coating agent, a coating formation method, and a coating layer that impart high hardness, heat resistance, scratch resistance, acid resistance, chemical resistance, high stability, etc. to a glass substrate. [Means for solving the problem]

[0011] The present inventors have discovered that a coating agent for glass substrates containing a hydrolysis condensation product of an alkoxysilane compound and water in the presence of an acid catalyst and a solvent, wherein the alkoxysilane compound and the water are present in a specific part by mass ratio, the hydrolysis condensation product has a specific weight-average molecular weight, and the solids concentration of the hydrolysis condensation product is a specific % by mass, can form a coating that is high in hardness and has excellent heat resistance, scratch resistance, acid resistance, chemical resistance, high stability, etc., and also has an excellent appearance, which led to the present invention.

[0012] That is, the present invention is as follows. [1] A coating agent for glass substrates, comprising a hydrolysis condensation product of an alkoxysilane compound and water under an acid catalyst, and a solvent, the mass part ratio of the alkoxysilane compound to the water is 1:0.1 to 1:5; the weight-average molecular weight of the hydrolysis-condensation product is 1,000 to 20,000; the solid content concentration of the hydrolysis-condensation product is 0.1 to 50 mass%. The coating agent. [2] A coating forming method in which the coating agent is applied and then baked at 500°C or higher. [3] The coating forming method, wherein the coating agent is applied by any one of a dipping method, a spin method, and a spray method. [4] A coating layer formed from the coating agent, having a thickness of 10 to 300 nm and a haze value of 0.01 to 0.9. [Effects of the Invention]

[0013] By using the glass substrate coating agent and coating formation method of the present invention, it is possible to form a coating on a glass substrate that has high hardness, excellent heat resistance, scratch resistance, acid resistance, chemical resistance, high stability, etc., and also has an excellent appearance. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention will now be described in more detail. The coating agent of the present invention contains 0.1 to 5 mass % of water and 0.1 to 5 mass % of solids based on the alkoxysilane compound. The coating agent is composed of a solvent and a hydrolysis condensation product of an alkoxysilane compound having a weight average molecular weight of 1,000 to 20,000, which has been hydrolyzed and condensed in the presence of an acid catalyst at a concentration of 0.1 to 50%.

[0015] Usable trialkoxysilane compounds include methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatepropyltriethoxysilane, trifluoropropyltriethoxysilane, and methyltriethoxysilane. Trimethoxysilane, trifluoropropyltriethoxysilane, 1H,1H,2H,2H-nonafluorohexyltrimethoxysilane, 1H,1H,2H,2H-nonafluorohexyltriethoxysilane, 1H,1H,2H,2H-tridecafluoronormal-octyltrimethoxysilane, 1H,1H,2H,2H-tridecafluoronormal-octyltriethoxysilane, 1H,1H,2H,2H-heptadecafluorodecyltrimethoxysilane, 1H,1H,2H,2H-heptadecafluorodecyltriethoxysilane, [5, 5,6,6,7,7,7-heptafluoro-4,4-bis(trifluoromethyl)heptyl] Trialkoxysilanes such as trimethoxysilane and [5,5,6,6,7,7,7-heptafluoro-4,4-bis(trifluoromethyl)heptyl]triethoxysilane, and tetraalkoxysilanes Examples include, but are not limited to, compounds co-condensed with alkoxysilane. These may be used alone or in combination of two or more. The alkoxysilane compound in the present invention is a compound in which an alkoxy group is bonded to silicon, and includes tetraalkoxysilane, ethyl silicate, methyl silicate, and oligomers thereof. These may be used alone or in combination of two or more. Among these, ethyl silicate oligomer is particularly preferred.

[0016] Examples of ethyl silicate oligomer products include the MS series manufactured by Mitsubishi Chemical Corporation and the Ethyl Silicate series manufactured by Colcoat Co., Ltd.

[0017] The molecular weight of the alkoxysilane compound may be high molecular weight of 2,000 or more, medium molecular weight in the range of 450 to 1,500, low molecular weight of 250 or less, or with a high or low water content, but medium molecular weight oligomers are preferred. If it is less than 1,000, the coating properties after baking will be insufficient and acid resistance will not be exhibited. If it is more than 20,000, the stability over time will be poor, and the film thickness may not be uniform, or unevenness may occur.

[0018] Examples of solvents used in the present invention include alcohols such as methanol, ethanol, n-propanol, isopropyl alcohol, and n-butanol; glycol derivatives such as ethylene glycol and ethylene glycol monomethyl ether; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and ethers such as methyl cellosolve and ethyl cellosolve. These organic compounds can be used alone or in combination. Among these, ethanol and ethyl acetate are preferred. The amount of these organic solvents used is preferably 50 to 99%. If the amount of organic solvent in the reaction system is less than this range, the stability of the resulting solution over time will decrease. On the other hand, if the amount is too high, the hydrolysis and polycondensation reactions will proceed more slowly, requiring a long maturation period to obtain the desired hydrolysis-condensation product. Furthermore, a combination of ethanol and ethyl acetate is preferred.

[0019] The content of the catalyst in the silane compound is preferably 0.05 to 10 mass %, more preferably 0.1 to 5.0 mass %. If the amount is less than the above range, the effect of promoting the production of the silane compound partial hydrolysis condensation oligomer tends to be insufficient, whereas if the amount is more than the above range, the production of the silane compound partial hydrolysis condensation oligomer tends to be non-uniform.

[0020] Specific examples of acid catalysts include, but are not limited to, hydrochloric acid, sulfuric acid, nitric acid, p-toluenesulfonic acid, benzenesulfonic acid, 10-camphorsulfonic acid, formic acid, oxalic acid, acetic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, and lactic acid. Specific examples of the base catalyst include triethyleneamine, dimethylaminoethanol, and aqueous ammonia. Among these, the acid catalyst, nitric acid, is preferred. In the present invention, the above compounds can be used as catalysts either individually or in combination of two or more.

[0021] In the present invention, the solid content is the NV (Nonvolataile content: the ratio of the mass of the paint component after drying to the mass of the paint component before drying) of the treatment liquid, and although the main component is silica, other components are also included.

[0022] In the present invention, surfactants, viscosity agents, hydrophilic agents, water repellents, silica, and the like may be added as needed within the range that does not adversely affect the properties. More specifically, from the viewpoint of improving ease of application, a viscosity agent can be suitably used. Examples of viscosity agents include organic polymer materials, inorganic polymer materials, fine particles, microgels, solvents, etc., but any other solvent with high viscosity can also be used as the viscosity agent.

[0023] The coating agent can be applied in the coating formation method of the present invention by dipping, air spraying, airless spraying, spin coating, roll coating, gravure coating, or the like. Among these, the coating formation method using the dipping method is preferred because it allows relatively accurate control of the film thickness and is industrially highly productive. The immersion time in the dipping method is preferably 1 to 120 seconds. If it is less than 1 second, there is a risk that the coating agent will not be sufficiently applied to the glass substrate, and if it is immersed for more than 120 seconds, the thickness of the coating film will not change significantly, and productivity is likely to be reduced. The lifting speed in the dipping method is preferably 1 to 50 mm / sec, more preferably 2 to 10 mm / sec. If it is less than 1 mm / sec, the coating film may become too thin, which may actually reduce productivity. If it exceeds 50 mm / sec, the coating film may become too thick or may become uneven in thickness. There are no particular limitations on the coating forming device used in the dipping method, and for example, a Dip Coater DT-0303 (manufactured by SDI Corporation) can be used.

[0024] The thickness of the bake-hardened coating film is preferably in the range of 10 to 500 nm, more preferably 10 to 300 nm, and if it is less than 10 nm, the protective effect of the coating film is reduced and coating defects such as pinholes are likely to occur.On the other hand, if it is thicker than 500 nm, interference patterns are likely to occur, durability is insufficient, but cost efficiency is poor, cracks are likely to occur, and adhesion is reduced due to internal stress during coating film formation. For baking, it is preferable to bake in an oven at 500°C or higher for 10 minutes.

[0025] The glass substrate to which the glass substrate coating agent of the present invention can be applied includes glass materials such as glass plates and glass cloths, glass parts, and any other glass substrates regardless of shape, and further, it can be applied to glass ceramics, ceramic materials, and the like. We also produce outdoor glass products, indoor glass products, showcases, window glass, automotive glass, It can be applied to glass substrates for a variety of purposes, including partitions and displays. [Example]

[0026] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" means parts by mass unless otherwise specified.

[0027] <Glass substrate coating agent> A 100mm x 200mm x 3.3mm borosilicate heat-resistant glass plate manufactured by Schott Corporation was used as the glass substrate. The alkoxysilane compounds used were, as shown in Tables 1 and 2, silicate oligomer 1 (Silicate 40 manufactured by Tama Chemicals Co., Ltd.). This mixture of polyethyl silicate, tetraethoxysilane, and a solvent had a non-volatile content of 100% by mass. The non-volatile content was 60-70% polyethyl silicate, 0.1-5 parts water, and 0.1-50% solids. Ethanol was added as a solvent to the mixture to obtain a glass substrate coating agent. The resulting mixture contained 2 parts by mass of an alkoxysilane compound with a weight average molecular weight of 1,000-20,000, obtained by hydrolysis and condensation of 0.1-50% water under a nitric acid catalyst. Furthermore, silica, a surfactant, and a viscosity improver were added as additives as needed.

[0028] <Coating formation method> The glass substrate coating agent was applied to the prepared glass plate by dipping, and baked in a drying furnace manufactured by Yamato Scientific Co., Ltd. at 600° C. for 10 minutes. The thickness of the resulting coating layers was in the range of 10 to 300 nm.

[0029] [Table 1]

[0030] Silane Compounds (1) <Synthesis example> [Preparation of Nitric Acid Solution 1] The following was mixed to obtain a nitric acid solution 1 as a catalyst. 10% nitric acid aqueous solution 1.0 parts by mass Water 3.0 parts by mass Ethanol 30 parts by mass

[0031] [Preparation of silicate binder 1] First, the following were mixed to obtain a mixed solution. Silicate oligomer 1 8.0 parts by mass Ethanol 30 parts by mass Then, 34 parts by mass of the nitric acid solution 1 obtained above was added dropwise while stirring and mixing at 40° C. for 1 hour. Next, the following was further added and mixed with stirring to obtain a silane compound (1) with a solid content of 4%. Ethanol 28.0 parts by mass

[0032] Silane compound (2) was obtained by changing the reaction temperature from 40°C for 1 hour to 50°C for 3 hours in the synthesis of silane compound (1). Silane compound (3) was obtained by changing the reaction time from 1 hour at 40°C to 0.5 hours at 40°C in the synthesis of silane compound (1). Silane compound (4) was obtained by changing the water content from 3.0 to 6.0 in the synthesis of silane compound (1) above, and changing the temperature from 40°C for 1 hour to 40°C for 0.5 hours. Silane compound (5) was obtained by changing the amount of water from 3.0 to 1.5 in the synthesis of silane compound (1) above, and changing the reaction time from 40°C for 1 hour to 50°C for 1.5 hours. Silane compound (6) was obtained by diluting the silicate 40 with an ethanol solvent.

[0033] [Table 2]

[0034] [Comparative Example 3] See also Example 1 of JP 2024-016433 A. Manufacturing Example 1 In a 1-liter flask, add tetraethoxysilane (S) as the tetraalkoxysilane compound. iO 2 40 parts by mass) 35 parts by mass, ethanol 18 parts by mass as an alcohol solvent with a short alkyl group The contents were charged and mixed at room temperature using a disperser while stirring. An aqueous solution of 4 parts of 10% nitric acid as a strong acid catalyst, diluted with 20 parts of water, was added dropwise to the flask, and stirring was stopped. The mixture was then stored at 30°C for 6 hours to obtain a hydrolysis condensation product (A) of the tetraalkoxysilane compound. Thereafter, while stirring with a disperser, a premix of 5 parts of isobutyl alcohol, 403 parts of ethanol, and 15 parts of methanol was added as an alcohol or glycol ether-based organic solvent (B) to dilute the mixture, and the mixture was filtered through a 1 μm filter to obtain 500 parts of a treatment liquid (heating residue: 2.8%). Manufacturing Example 2 500 parts of an AG treatment liquid (heating residue 2.8%) was obtained in the same manner as in Production Example 1, except that 403 parts of propylene glycol monomethyl ether acetate was used instead of 403 parts of ethanol as a solvent for diluting the hydrolysis condensate (A) of a tetraalkoxysilane compound. The treatment liquid obtained in Production Example 1 was spray-coated using a precision coating machine (manufactured by Apiros Co., Ltd.) to form an AG coating film with a coating thickness of approximately 0.4 μm. NB06-04 of the AF treatment liquid (manufactured by Katsuraya Co., Ltd.) was then sprayed onto the AG coating film using the same precision coating machine (manufactured by Apiros Co., Ltd.). After spraying the coating, it was baked at 150°C for 30 minutes to form a multilayer coating. .

[0035] [Comparative Example 4] See also the adjustment described in Patent Application No. 2023-031503. 1. Raw materials used in the examples Tetraethoxysilane: Shin-Etsu Chemical Co., Ltd., KBE-04. 3-Glycidoxypropyltriethoxysilane: KBE-403 manufactured by Shin-Etsu Chemical Co., Ltd. 3-Aminopropyltriethoxysilane: KBE-903 manufactured by Shin-Etsu Chemical Co., Ltd. Inorganic fine particle dispersion 1: IPA-ST manufactured by Nissan Chemical Co., Ltd. NV30%, spherical, particle size 10 nm. IPA solution. Inorganic fine particle dispersion 2: Sururia 1110 manufactured by JGC Catalysts and Chemicals Co., Ltd. NV 20.5%, hollow, particle size 50 nm. IPA solution. ·Inorganic fine particle dispersion liquid 3: IPA-ST-UP manufactured by Nissan Chemical Co., Ltd. NV15%, chain-like, particle size 10nm. IPA solution. 2. Preparation of Binder Solution (Preparation of binder liquid 1) First, the following was mixed to prepare an aqueous acid catalyst solution 1. Water 130 parts by mass 10% nitric acid 26 parts by mass Next, tetraethoxysilane and ethanol were placed in a flask in the ratio shown below and mixed by stirring with a disper, and while stirring, the aqueous acid catalyst solution 1 was added dropwise while adjusting the internal temperature so that it did not exceed 30°C. After the dropwise addition was completed, stirring was stopped and the mixture was allowed to stand at 30° C. for 6 hours to obtain 500 parts by mass of binder liquid 1. 227 parts by mass of tetraethoxysilane, Ethanol 117 parts by mass Acid catalyst aqueous solution 1 156 parts by mass (Preparation of binder solutions 2 to 4) Binder solutions 2 to 4 were prepared in the same manner as binder solution 1, according to the formulation and conditions shown in Table 1.

[0036] [Example 1] The binder liquid 1 obtained above, inorganic fine particle solution 1, IPA (isopropyl alcohol), PNP (propylene glycol n-propyl ether), and EG (ethylene glycol) were mixed with stirring in the following ratios using a disper. Binder liquid 1 0.35 parts by mass Inorganic fine particle dispersion 1 5.8 parts by mass IPA 61.1 parts by mass PNP 16.3 parts by mass EG 16.3 parts by mass The mixture was then filtered through a filter with a sieve diameter of 1 μm to obtain adhesive composition 1 (solid content: 2.1% by mass). The adhesive was applied by spray coating so that the thickness of the dried layer was 120 nm, and then dried at 80°C for 5 minutes to form an adhesive layer. Silane compound (7) (30% KBM403 aqueous solution, solid content 20%) 70 parts by mass of ionized water was mixed with 30 parts by mass of KBM403 manufactured by Shin-Etsu Chemical Co., Ltd., and stirred at room temperature for 3 hours to obtain a solution with a solid content of 20%.

[0037] [Comparative Example 5] Water repellent After applying AF processing liquid NB06-04 manufactured by Katsurayama Technology Co., Ltd., the film was baked at 150°C for 30 minutes.

[0038] [Comparative Example 6] Hydrophilic Agent After applying the glass coating agent SUPER Pika Pika Rain manufactured by Toplan, it was dried at 80°C for 30 minutes.

[0039] <Evaluation method> (1)Hardness The test was evaluated according to 4.4 Scratch hardness (pencil method) of JIS K5600 General Test Method for Paints.

[0040] (2) Scratch resistance The coated piece was rubbed 10 times with a metal brush under a 500 g load and the appearance was evaluated. The evaluation criteria are as follows: ○ No change △ Slight peeling × Peeling

[0041] (3) Acid resistance The coated specimens were placed in a sealed container with 98% sulfuric acid and left at 210°C for 24 hours before evaluation. The evaluation criteria are as follows: ○ No change ○△ Defects are confirmed under a microscope △ Partially bleached △× Light whitening all over × Full whitening

[0042] (4) Boiling water resistance The coated specimens were immersed in ion-boiling water at 100°C for 2 hours and evaluated. The evaluation criteria are as follows: ○ No change △ Peels off when rubbed × Peeling

[0043] (5) Appearance The appearance was evaluated visually. The evaluation criteria are as follows: Uniform transparent appearance 〇△ Slight unevenness △ There are slight unevenness or white spots × Uneven appearance due to unevenness or lumps

[0044] (6) Stability The molecular weight was evaluated based on the increase in molecular weight after being left in an environment of 40°C for one month. The evaluation criteria are as follows: ◎ Molecular weight within 1.1 times after 1 month at 40℃ Molecular weight within 1.5 times after 1 month at 40℃ Molecular weight within 3 times after 1 month at 40℃ × 40℃ Molecular weight more than 3 times after 1 month

[0045] Examples 1 to 10 and Comparative Examples 1 to 6 were evaluated using the evaluation methods described above. The evaluation results are shown in Tables 1 and 2 above.

[0046] <Evaluation results> In all of the categories of hardness, scratch resistance, acid resistance, chemical resistance, appearance, and stability, products rated as "good" or better were deemed effective, and products rated as "good" or worse in any of the above evaluation items were deemed ineffective.

[0047] <Examples 1 to 10> For all of silane compounds 1 to 5, when an organic solvent was used as the solvent and the molecular weight was 1,000 to 20,000, the compounds were rated as "good" or better in all evaluations of hardness, scratch resistance, acid resistance, chemical resistance, appearance, and stability.

[0048] <Comparative Examples 1 to 6> In Comparative Example 1, the raw material ethyl silicate 40 had a small molecular weight, and therefore sufficient hardness, scratch resistance, and acid resistance were not obtained. In Comparative Example 2, the silicate oligomer containing only a water solvent did not provide a sufficiently stable appearance. In Comparative Example 3, sufficient acid resistance was not obtained. Furthermore, in Comparative Example 4, boiling water resistance as well as acid resistance was not obtained. The existing water-repellent material of Comparative Example 5 did not provide sufficient performance. Furthermore, the commercially available hydrophilic silicate agent of Comparative Example 6 also failed to provide sufficient performance.

[0049] As is clear from the above results, the coating agent of the present invention has high adhesion to glass substrates. This coating agent exerts the effect of imparting hardness, heat resistance, scratch resistance, acid resistance, chemical resistance, high stability, etc., and the coating formation method and coating layer using this coating agent also exert the effect of imparting high hardness, heat resistance, scratch resistance, acid resistance, chemical resistance, high stability, etc., in the same manner as described above. [Industrial Applicability]

[0050] The present invention uses a specific alkoxysilane compound to form a coating on a glass substrate that is highly durable and heat-resistant, enabling glass materials used in a variety of applications to be used for a long period of time through the coating, and is therefore extremely useful industrially.

Claims

1. A coating agent for glass substrates, comprising a hydrolysis condensate of an alkoxysilane compound and water under an acid catalyst, and a solvent, the mass ratio of the alkoxysilane compound to the water is 1:0.1 to 1:5; the weight-average molecular weight of the hydrolysis-condensation product is 1,000 to 20,000; the solid content concentration of the hydrolysis-condensation product is 0.1 to 50 mass%; The coating agent.

2. A method for forming a coating, comprising applying the coating agent according to claim 1 and then baking the applied coating agent at 500°C or higher.

3. 3. The method of claim 2, wherein the coating agent is applied by any one of a dipping method, a spin method, and a spray method.

4. A coating layer formed from the coating agent according to claim 1, having a thickness of 10 to 300 nm and a haze value of 0.01 to 0.9.

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