JPH1111984A - Water-repellent glass and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress fluctuation in qualities such as light resistance and wear resistance by forming a water-repellent layer on a glass surface, applying a silane compd. containing fluorine to form a thin film on the water-repellent layer, and deactivating unreacted groups in the thin film. SOLUTION: As the glass substrate, an inorg. transparent sheet glass such as float glass is preferable. As the coating liquid for a water-repellent layer, a silane compd. containing fluoroalkyl groups (e.g. fluoroalkylalkoxy silane compd.) is used, and isopropylalcohol or the like is used as a diluting solvent. As an acid catalyst, 0.1 to 13N nitric acid is used to hydrolyze the silane compd. After the reaction is completed, the water content in the coating liquid for the water-repellent layer is controlled (to <=4000 ppm water content) and the condensation polymn. degree is controlled. The coating liquid is applied on the substrate surface while temp. and humidity are controlled, and dried and cured at room temp. to <=350 deg.C for 1 to 60 min to form a water-repellent layer. In the final stage, unreacted groups (silanole groups) in the water-repellent layer are deactivated with a silylating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a water-repellent glass used in various glass articles in various fields such as window materials for buildings and automobiles, and window materials for ships and aircrafts, and a method for producing the same. Is what you do.

[0002]

2. Description of the Related Art Recently, a highly durable water-repellent glass having a long water-repellent performance has been desired. Regarding this highly durable water-repellent glass and a method for producing the same, for example, Japanese Patent Application Laid-Open No. Hei 6-16455 filed by the present applicant discloses a method of providing a silica base film having an irregular shape on the glass surface. Japanese Patent Application No. 8-131595 discloses a method of forming a water-repellent layer while keeping a glass substrate at a high temperature of 90 to 200 ° C. Japanese Patent Application No. 8-333329 discloses a method of polishing a glass surface with ceria. It has been proposed that a method of forming a water-repellent layer in an environment treated with an acid and controlling the temperature and humidity is effective.

[0003] As for a method of inactivating a glass surface, for example, Japanese Patent Application Laid-Open No. 7-109131 discloses a method of press-molding heat-softened glass to produce a glass product. Alternatively, there is known a production method for extending the life of a mold by using glass in which hydrogen atoms of all silanol groups are substituted with inert groups.

[0004]

With respect to the above-mentioned conventional water-repellent glass, a method of finishing and wiping the glass surface on which the water-repellent layer is formed with an alcoholic solvent (for example, isopropyl alcohol) in the finishing step. Although generally used, the glass obtained after the final wiping has a problem in that quality such as light resistance and abrasion resistance varies.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in pursuit of various causes of quality variations after finish wiping in the above-mentioned conventional finishing process. The previous water-repellent layer is between room temperature and about 35
Although a curing treatment at 0 ° C. is performed, a large amount of unreacted silanol groups (Si—OH) which have not been added to the reaction with the glass surface or the water repellent component remain in the water repellent layer. The unreacted groups react with an alcoholic solvent (eg, isopropyl alcohol) used in the finish wiping in the finishing step, and the quality of the water-repellent glass after the finishing step varies depending on the degree of the remaining unreacted groups. It has been found.

The present invention relates to a water-repellent glass comprising a thin film in which a fluorine-containing silane compound is coated on a water-repellent layer formed on a glass surface to inactivate unreacted groups, and a method for producing the same. Due to the deactivation, the quality of the water-repellent glass does not vary even if the alcohol is wiped in the finishing step, and a stable and excellent quality water-repellent glass can be easily obtained.

That is, the present invention is a water-repellent glass in which the water-repellent layer formed on the glass surface is a thin film in which unreacted groups are inactivated by coating a fluorine-containing silane compound.
The water-repellent layer is most preferably formed by fixing a fluoroalkyl group to the glass surface by a siloxane bond.

The water-repellent film is preferably formed on a base layer made of a metal oxide film. The underlayer made of a metal oxide is preferably formed of SiO ₂ or TiO ₂ .

The present invention also provides a water-repellent layer formed by applying a component to a glass surface by subjecting a silane compound containing a fluoroalkyl group to hydrolysis and dehydration-condensation polymerization. The present invention relates to a method for producing a water-repellent glass, characterized by inactivating unreacted groups in a water-repellent layer by treating with a treatment liquid contained in the water-repellent layer.

[0010] The concentration of the silylating agent in the treatment solution is from 1 to 2
0 wt% is preferred. The solvent for the silylating agent is preferably non-alcoholic. Furthermore, it is preferable to form a water-repellent layer after modifying the glass surface, and to treat with the treatment liquid.

As a method of surface modification, ceria polishing and acid treatment are suitable.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A water-repellent layer formed on a glass surface
A water-repellent glass composed of a thin film coated with a fluorine-containing silane compound and inactivating unreacted groups can be obtained as follows.

In preparing the coating solution for the water-repellent layer, a hydroalkyl group-containing silane compound is used to terminate the hydrolysis reaction of the silane compound containing the fluoroalkyl group. Preparing, preparing a coating solution for the water-repellent layer having a controlled degree of polycondensation, applying the prepared coating solution for the water-repellent layer on the surface of the glass substrate while controlling the temperature and humidity, and room temperature to about 350 ° C. After drying and curing for 1 minute to 60 minutes below to form a water repellent layer, the glass is treated with a treatment liquid containing a silylating agent in a solvent to remove unreacted groups in the water repellent layer. Inactivate.

The glass substrate is preferably a glass plate having various inorganic transparency such as float glass used for architectural window glass or automotive window glass, and may be colorless or colored, or an arbitrary one. . Further, a film having a thin film surface such as silica, another functional film, or a film having another surface may be used. The shape is not particularly limited,
Not only bent glass but also various tempered glass and strengthened glass can be used as a flat plate or a single plate, and can also be used as a double glazing or a laminated glass.

As a silane compound containing a fluoroalkyl group,
Are fluoroalkylalkoxysilane-based compounds (hereinafter
Below, referred to as FAS). Fluoroalkylua
Lucoxysilane-based compounds include, for example, CF_3CH_TwoCH_TwoSi
(OMe)_Three , CF_Three(CF_Two)_FiveCH_TwoCH_TwoSi (OMe)_Three , CF_Three(CF_Two)₇CH_TwoCH_Two
Si (OMe)_Three , CF_Three(CF_Two)₉CH_TwoCH_TwoSi (OMe)_3, CF_Three(CF_Two)₁₁CH _Two
CH_TwoSi (OMe)_3, CF_Three(CF_Two)₇CH_TwoCH_TwoSiMe (OMe)_Two Etc.
It is.

The silanol group on the glass surface can be sufficiently converted without requiring hydrolysis, such as a fluoroisocyanate silane compound or a fluoroalkyl halide silane compound, which is generally classified as a fluoroalkyl group-containing silane compound. Those which can form a siloxane bond by reaction can be sufficiently used as a coating solution for a water-repellent film without controlling the hydrolysis and condensation polymerization reactions.

As a diluting solvent, in addition to isopropyl alcohol (hereinafter abbreviated as i-PA), a lower alcohol solvent having 5 or less carbon atoms such as methanol and ethanol may be used. In addition, ethers and ketones can be used in addition to alcohol, and alcohol containing isopropyl alcohol as a main component is preferable as a diluting solvent in preparing a coating solution.

Examples of the acid catalyst for hydrolyzing the fluoroalkyl group-containing silane compound include nitric acid having a concentration of 0.01N or more, preferably about 0.1N to 13N, organic acids such as acetic acid, hydrochloric acid, and sulfuric acid. And so on. What is important is the amount of water from the acid catalyst, and the amount of water is determined by the acid concentration in the acid catalyst and the amount of the acid catalyst itself.

The coating liquid for the water-repellent film is expressed in g, starting material amount: diluting solvent amount: water content from acid catalyst =
Compositions having a ratio of 1: 5 to 50: 0.09 to 1.0 are preferred. That is, a fluoroalkyl group-containing silane compound (hereinafter abbreviated as FAS) as a starting material and iP as a diluting solvent
A, 0.1N-HNO ₃ is used as the acid catalyst, and the coating solution for the water-repellent film is F
AS: i-PA: moisture content of from _{0.1N-HNO 3 = 1: 5~50} : 0.3
(G = indicated), dehydrating agent is molecular sieve 4A (dehydration time: 2 to 24 h, dipping amount: 5 g), and coating environment is room temperature
A coating solution was prepared under conditions of a humidity of 55% RH or less to form a film.

Further, regarding the adjustment of the water content in the coating solution for the water-repellent film, FAS was used as a starting material, and
i-PA, using 0.1N-HNO ₃ as an acid catalyst, and the coating solution for the water-repellent film is FAS: i-PA: water content from 0.1N-HNO ₃ = 1: 25: 0.3
(G = display), type of dehydrating agent (Molecular sieve 4A)
And 3A), the amount (1 g, 2.5 g, 5 g) and the amount of water (ppm) after dehydration time (h) were determined over time. As a result, the contact angle was about 95 ° after 3,500 traverse sliding operations. If the above is the dehydration time is 1-2h or more, the water content is about 4000ppm
The water content is preferably about 3000 ppm or less, more preferably about 2000 ppm or less. Examples of the dehydrating agent include molecular sieve, calcium chloride, magnesium sulfate and sodium sulfate.

The water content in the coating solution for the water-repellent film is as follows:
It was determined by using a Karl Fisher coulometric titration method. The presence of the silanol group is measured as a water content.

Further, the prepared coating solution for the water-repellent film is applied on the surface of the glass substrate while controlling the temperature and humidity. FAS as starting material, i-PA as diluting solvent, 0.1N-HNO as acid catalyst
₃ , the water-repellent coating liquid was FAS: i-PA: 0.1N-HNO3, the amount of water from 1: ₃ : 25 (0.3 g), and the dehydrating agent was molecular sieve 4A (dehydration time). : 16h, immersion amount: 5g)
A coating solution was prepared under the following conditions. 15% RH at room temperature
A coating film of the coating solution was formed under the condition of humidity of 90> 90% RH.
After drying and curing at about 140 ° C for about 5 minutes,
Determine the contact angle (°) at 3,500 times of sliding and evaluate the traverse resistance, and evaluate the influence on the ambient humidity (% RH) and traverse resistance when coating with the coating solution for water-repellent film. Examined.
Even when the atmospheric humidity is about 80% RH,
Some contact angles after 500 times are 80 ° or more and 101 ° or less, and even if the atmospheric humidity is 70 to 80% RH, it may be good in some cases, but it is surely about 75% RH or less. Humidity less than about 60% RH, more preferably about 60% RH
It should be about 15% RH or less, preferably about 55% RH or less and about 15% RH or less.

Further, the suitability of the surface condition of the glass substrate was examined. FAS as starting material, iP as diluting solvent
A, 0.1N-HNO ₃ is used as the acid catalyst, and the coating solution for the water-repellent film is F
AS: i-PA: moisture content of from _{0.1N-HNO 3 = 1: 25} : 0.3
(G = display), the dehydrating agent is molecular sieve 4A (immersion amount: 5 g), the dehydrating condition is immersion for about 24 hours at room temperature, and then filtered with NO.7 filter paper. It was assumed that there was no burn due to interleaving paper. After coating with the coating solution for the water-repellent film, the top surface of the float glass (water washing only) was cured under the conditions of curing in a medium-sized hot air circulation furnace (plate temperature: about 140 ° C, temperature rise: 5 minutes, keeping: 5 minutes). ) And film formation on the bottom surface (ceria polishing and water washing), and evaluated the relationship between the S-UV irradiation time (h) and the contact angle (°) in a light resistance test (see Example 1 described later). The influence on the S-UV irradiation time on the top and bottom surfaces of the float glass was determined. As a result, at the S-UV irradiation time of about 600 hours (h), the top face was about 70 °, while the bottom face was about 50 °, and there was a clear difference between the top and bottom faces of the float glass. Yes, it is preferable to cover the top surface of the float glass, which is the fire-making surface.

On the other hand, when the contact angle θ (°) after 3,500 sliding times was determined, the contact angle was> 100 ° on the top surface of the float glass, and 50-100 ° on the bottom surface. Was. Therefore, it is preferable to coat the top surface of the float glass.

The top surface and the bottom surface are also free from burnt interleaving paper, and are sufficiently polished with a brush or sponge made of ceria or alumina as an abrasive, and then sufficiently washed with water to achieve a contact angle of> 100 °. Can be secured.

Further, as a method of forming a water-repellent layer on a glass substrate, there are a hand coating method, a nozzle flow coating method, a dipping method, a spray method, a reverse coating method, a flexo method, a printing method, and a flow method. Coating method or spin coating method,
In addition, known coating means such as a combination thereof can be appropriately employed.

In order to fix a fluoroalkyl group on the glass surface by a siloxane bond, the polished glass surface is treated with an inorganic acid such as hydrochloric acid, sulfuric acid or nitric acid or an organic acid such as acetic acid, formic acid or oxalic acid with PH4. Using an acid treatment solution consisting of an aqueous solution added and prepared so as to have a concentration of not more than
The temperature of the acid treatment liquid is 5 ° C. to 70 ° C. or less, and the treatment time is 10
By acid treatment under the conditions of ~ 600 seconds, the extraction of sodium ions and the breaking of siloxane bonds on the surface of the polished glass so as to efficiently generate silanol groups,
It is preferable that the silanol group contributes to the fixation of the water-repellent fluoroalkyl group in the water-repellent treatment in the subsequent step.

The reason why the temperature of the acid treatment is 5 to 70 ° C. is as follows.
When the temperature is lower than 70 ° C., the speed of the silanol group formation reaction is greatly reduced. When the temperature is higher than 70 ° C., the speed of the silanol group formation reaction is increased. Inconveniences such as a decrease in the acid concentration due to water evaporation and fluctuations in the acid concentration due to evaporation of water and corrosion of peripheral equipment due to evaporation of the acid components will occur.

The reason for setting the acid treatment time to 10 to 600 seconds is as follows.
If the treatment time is less than 10 seconds, it is not possible to efficiently generate silanol groups by extracting sodium ions from the glass surface or breaking siloxane bonds, and if the treatment time exceeds 600 seconds, the production efficiency in the actual mass production line will be reduced. Bad and not desirable.

Preferably, the acid treatment solution has a pH of 3.5 or less, the temperature of the solution is 10 to 60 ° C., and the treatment time is 15 to 42 hours.
The acid treatment may be performed under the condition of 0 second. Further, it is preferable to form a metal oxide layer such as SiO ₂ or TiO ₂ as a base layer of the water repellent layer because the film strength and adhesion of the water repellent layer are improved. SiO ₂ ,
It is not limited to TiO ₂ . Further, various additives may be contained.

The silylating agent used to inactivate the unreacted groups in the water-repellent layer can be used to inactivate the silanol groups remaining in the water-repellent layer after curing, so that light resistance and light resistance can be improved. For improving the chemical resistance to alcoholic solvents, hexamethyldisilazane (CH ₃ ) ₃ SiNHSi (C
H ₃ ) ₃ and trimethylchlorosilane (CH ₃ ) ₃ SiCl are used. The concentration of the silylating agent is 1 to 20 wt% based on the processing solution.
This dilution is preferably performed using a non-alcoholic solvent such as pyridine, and the temperature of the water-repellent glass is from room temperature to 50 ° C.
It is preferable to apply and dry at a temperature of ° C, but the present invention is not limited to this. The reaction with silanol groups in the water-repellent layer when trimethylchlorosilane is used as a silylating agent is represented by the following formula.

[0032]

Embedded image

As a solvent for the silylating agent, a non-alcoholic solvent is preferably used since an alcoholic solvent reacts with the silylating agent. The drying and curing for 1 minute to 60 minutes at room temperature or more and 350 ° C. or less are performed to form a film by the S-UV irradiation time (h).
And the contact angle (°) was evaluated. As a result, the contact angle was about 70 ° or more and about 70 to 80 ° even when the S-UV irradiation time was about 600 hours (h). It is something. Therefore, for drying and curing, the temperature is 50 ° C or more and 35
1 minute to 60 minutes at 0 ° C. or less. Preferably about 80 ° C
Drying and curing are preferably performed at a temperature of about 300 ° C. or less.

By inactivating unreacted groups in the water-repellent layer, even when wiping with alcohol in the finishing step, the quality of the water-repellent glass does not vary and a stable and excellent quality water-repellent glass can be easily obtained. Can be obtained. The obtained water-repellent layer is a water-repellent thin film having extremely excellent chemical resistance and light resistance, has high hardness and high adhesion, and has both durability and abrasion resistance. Further, according to the production method of the present invention, it is possible to form a film easily and efficiently with high controllability, extremely stable, high safety and no troublesome steps, and to obtain excellent water repellency over a long period of time. It can be maintained and the variation width of the water-repellent performance can be reduced, resulting in more reliable and stable quality.

[0035]

The present invention will be described below in detail with reference to examples. However, the present invention is not limited to these examples.

Example 1 Glass: Float flat plate reinforced glass of 200 × 300 × 3.5 (thickness) mm. A lath was used. Polishing: Ceria (Miritsu Metal Industry's “Mirek (A +
B) ': Water = 1: 100 (wt%) Using a suspension, the glass surface was polished with a brush polisher and then sufficiently washed.

Acid treatment: 1 in 35 ° C. sulfuric acid aqueous solution (0.1N)
After immersing the glass for minutes, it was washed with water. Water repellent treatment: Fluoroalkylalkoxysilane [FAS is used as a raw material of a water repellent solution composition for forming a water repellent film layer.
: CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , manufactured by Toshiba Silicone]
And isopropyl alcohol (iPA; manufactured by Kishida Chemical)
And 0.1N-nitric acid (manufactured by Kishida Chemical Co., Ltd.), the mixing ratio of which is FAS: iPA: 0.1N-HNO ₃ = 1: 25: 0.3 (unit: g), and the mixture is stirred at room temperature for about 2 hours for hydrolysis reaction. Was made.

Next, about 5 g of molecular sieve 4A (manufactured by Kishida Chemical) was added to the solution subjected to the hydrolysis reaction, immersed and left for about 16 hours to complete the dehydration while performing the condensation polymerization reaction. No. 7) to separate and remove the molecular sieve 4A to obtain a coating solution. Next, the coating solution is applied by hand at room temperature and an environment of about 55% RH on the top surface of the glass substrate which has been subjected to ceria polishing, acid treatment, washing with tap water, and rinsing with distilled water. did.
Then, after application, air-cooled and dried at about 140 ° C for about 5
The film was formed by drying and curing for about a minute to obtain a glass with an F-SiOx film.

Inactivation: After the glass temperature has returned to room temperature after curing, a trimethylsilylation solution is applied by hand to the entire glass surface, and after drying, excess water repellent is wiped off to remove the water repellent glass. Obtained.

In the trimethylsilylation solution, pyridine (manufactured by Kishida Chemical) is used as a solvent, and trimethylchlorosilane (CH
3) 3SiCl (manufactured by Kishida Chemical) whose content was diluted to 10% was used.

[0041]

[Embodiment 2] An intermediate layer between glass and a water-repellent layer,
Example 1 except that the iO2 film was formed by the sol-gel method.
A sample was prepared under the same conditions as described above.

Formation of base film: A small amount of acid catalyst is added to a solution of tetraethoxysilane diluted with isopropyl alcohol.
(0.1N hydrochloric acid) and water were added, and the mixture was stirred for about 3 hours, and isopropyl alcohol was further added so that the solute concentration in terms of oxide became about 0.5 wt% to obtain a coating liquid. The viscosity of this solution was about 2.5 mPa · s. Next, the film-forming surface of the glass substrate is washed with water, dried, and then spin-coated (at a rotation speed of 200 rpm) with the coating solution in a clean room maintained at a temperature of 25 ° C. and a humidity of 50%.
Heating at 620 ° C. for 5 minutes gave a SiO 2 thin film. The obtained thin film had a refractive index of n = 1.45 and a thickness of d = 100 nm.

[0043]

Comparative Example 1 The same procedure as in Example 1 was carried out except that the step of inactivating was not performed.

[0044]

Comparative Example 2 Example 1 was repeated except that the content of trimethylchlorosilane in the passivation solution was 0.5 wt%.
The same conditions were used.

[0045]

Comparative Example 3 The same operation as in Example 1 was carried out except that isopropyl alcohol was used as a diluting solvent for the inactivation treatment liquid.

[0046]

(Water repellency test)

Measurement equipment: CA-X200 type manufactured by Kyowa Interface Science Measurement environment: Atmosphere (about 25 ° C) Water: Drop of pure water (2 μl) Evaluation: Drop the above water drop on the glass surface,
The angle (°) between the glass and the water droplet (ie, the contact angle) was measured. The contact angle before the test is indicated by θ ₀ (°), and the contact angle after each test is indicated by θ (°). [Abrasion resistance test] Tester: Traverse type sliding tester Sample size: about 100 mm × 200 mm Load on friction cloth: 0.1 kg / cm ^{2 on} canvas cloth (JIS L
3102-1206) Stroke: 100mm reciprocating sliding (the number of sliding is the number of reciprocating) Sliding speed: 30 reciprocating / min Evaluation: Contact angle θ for 3,500 sliding
(°) Measurement For the traverse test after wiping off the excess inert solution, set the paper towel containing isopropyl alcohol on the wiping glass sample and slide it 20 times using the same traverse tester as above. Thereafter, after sliding 20 more times with a dry paper towel, the above-mentioned regular abrasion resistance test was performed, and the contact angle after excessive wiping was measured. [Light resistance test] Measuring equipment: Super UV (S-UV) light resistance acceleration tester [Iwaki Electric, EYE SUPER UV TESTER, SV
U-W11 type].

Conditions: about 75 to 76 mW / cm ² , distance between lamp and sample about 25 mm, panel temperature about 50 ° C., SUV irradiation time about 2
00 hours, 400 hours, 600 hours. Evaluation: Contact angle θ for each SUV irradiation time
Measure (°).

[0048]

[Evaluation Results] The performance evaluation results in Examples and Comparative Examples are shown in Table 1 and FIG.

[0049]

[Table 1]

In the abrasion resistance test after wiping, in Examples 1 and 2, the contact angle was 104-105 ° and there was almost no variation and the value was 100 ° or more. No. 3 was not preferable because the variation was as large as 7 to 10 °.

Regarding the light resistance test, the contact angle after UV irradiation for 600 hours was such that the contact angles of Examples 1 and 2 were 80 ° or more, and the water repellency was maintained for a long time and the durability was high. On the other hand, all of the comparative examples were as low as about 70 °, had a large drop from the initial contact angle, and were poor in long-term durability.

As described above, in the case of carrying out the present invention, the unreacted groups in the water-repellent layer are inactivated, and the qualities such as light resistance, chemical resistance and abrasion resistance do not vary. In contrast, in Comparative Example 1, the unreacted groups were not inactivated in Comparative Example 1, and in Comparative Examples 2 and 3, the effect of inactivation was observed. Did not.

A light fastness test of a commercially available water-repellent sample showed that the contact angle θ was about 65 ° when the S-UV irradiation time was about 200 hours, which was extremely short life. .

[0054]

According to the present invention, by inactivating the unreacted groups in the water-repellent layer, the quality of the water-repellent glass does not vary even when the alcohol is wiped in the finishing step, and the water-repellent glass is stable and excellent in quality. Can be easily obtained. The obtained water-repellent layer is a water-repellent thin film having extremely excellent chemical resistance and light resistance, has high hardness and high adhesion, and has both durability and abrasion resistance. Further, according to the production method of the present invention, it is possible to form a film easily and efficiently with high controllability, extremely stable, high safety and no troublesome steps, and to obtain excellent water repellency over a long period of time. It can be maintained and the variation width of the water-repellent performance can be reduced, resulting in more reliable and stable quality.

Further, it can be supplied to window materials for automobiles as well as architectural materials with remarkably stable quality.
It is possible to provide a useful water-repellent glass having a high utility value that can be widely used in various fields such as various glass articles such as various mirrors and a method for producing the same.

[Brief description of the drawings]

FIG. 1 Relationship between S-UV irradiation time and contact angle

Claims (6)

[Claims] 1. A water-repellent glass, wherein the water-repellent layer formed on the surface of the glass is a thin film coated with a fluorine-containing silane compound to inactivate unreacted groups. 2. The water-repellent layer has a fluoroalkyl group fixed to the glass surface by a siloxane bond.
The water-repellent glass as described. 3. The water-repellent glass according to claim 1, wherein the water-repellent layer is formed on an underlayer made of a metal oxide film. 4. A water-repellent layer formed by coating a coating solution obtained by hydrolyzing and dehydrating and condensing a silane compound containing a fluoroalkyl group on the surface of a glass substrate. A method for producing a water-repellent glass, comprising inactivating unreacted groups in a water-repellent layer by treating with a treatment liquid contained therein. 5. The concentration of the silylating agent in the treatment solution is 1 to 5.
The method for producing a water-repellent glass according to claim 4, wherein the content is 20% by weight. 6. The method for producing water-repellent glass according to claim 4, wherein a water-repellent layer is formed on the glass whose surface has been modified, and then treated with the treatment liquid.