JPH06329442A - Water-repellent glass and its production - Google Patents

Abstract

PURPOSE:To produce a hard water-repellent glass excellent in adhesion and weather resistance. CONSTITUTION:This water-repellent glass is produced by coating a smooth or finely rugged glass substrate 1 with a water-repellent layer 2 composed of silica, a fluororesin and others and satisfying the weight ratio of the fluororesin to silica = (5 to 450):100. This glass is useful, e.g. as a window glass for vehicles, ships, aircrafts, architectures, etc., or mirrors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention not only has water repellent performance,
TECHNICAL FIELD The present invention relates to a water-repellent glass having excellent weather resistance and a method for producing the same, and more particularly to a water-repellent glass which is useful for window glasses or mirrors for vehicles, ships, aircraft, construction, etc. and a method for producing the same.

[0002]

2. Description of the Related Art In order to improve the water repellency of glass, it has been attempted to apply a compound such as a fluoroalkyl group-containing compound or dimethylsiloxane to the glass surface. However, simply coating these compounds has a weak binding force to the glass surface, and cannot provide sufficient weather resistance and abrasion resistance, and it has been difficult to maintain water repellency for a long period of time.

Up to now, a polyfluoroalkyl group (Rf group) has been used to impart water repellency on a material such as glass.
Various silane compounds containing have been proposed (JP-A-58-58).
122979, 58-129082, 58-1
No. 42958, No. 58-147483, No. 58-17.
2242, 58-172243, 58-172
No. 244, No. 58-172245, No. 58-1722
No. 46, No. 58-190840, No. 58-22363.
See Japanese Patent Publication No. 4).

Further, for example, Japanese Unexamined Patent Publication (Kokai) No. 58-167448 discloses a glass having a low reflectance, which is a thin film having a thickness of 1 μm or less and comprising a polyfluoroalkyl group-containing silane compound or a partial hydrolysis-condensation product of the compound. By forming on the glass surface, without impairing the transparency,
Those having low reflectance and water and oil repellency are disclosed. However, in such a conventional water repellent treatment method, it has been found by the durability and weather resistance tests that there is a problem that the water repellency deteriorates in a relatively short time.

Further, there is a glass coated with Teflon as one having excellent weather resistance, but there is a problem that the film is soft and easily scratched, and the transparency is immediately deteriorated.
Further, JP-A-60-231442 discloses a water repellent treatment in which a water repellent coating film is formed on a glass substrate, which comprises an organosilicon compound having a siloxane bond as an adhesive component and a polymer of a fluorine compound as a water repellent component. Although glass is described, it has a problem that it is easily scratched because it has a structure in which all or a relatively large amount of the surface water-repellent polymer is contained.

Further, Japanese Patent Laid-Open No. 3-153859 discloses that
A surface-modified plastic in which a metal oxide layer is formed on a plastic substrate and a composite layer of a metal oxide layer and a fluororesin is laminated on it is described, but the substrate is plastic, so the adhesion is not always satisfactory. There were problems such as not being able to do it. Further, JP-A-5-51238 describes a water-repellent glass having a water-repellent layer composed of a metal oxide layer and water-repellent fine particles dispersed in the metal oxide layer on a glass substrate. However, the structure in which the fine particles are evenly dispersed in the film has a problem in that it tends to be apt to stick.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide a water-repellent glass which is excellent in adhesion and weather resistance and is hard, and a method for producing the same.

[0008]

As a result of various studies to solve the above-mentioned problems, the present invention has at least silica.
(SiO ₂ ) and fluororesin, and the fluororesin is the S
This is based on the finding that the above object can be achieved by using a water-repellent glass formed by forming a water-repellent layer having a weight ratio of 5 to 450 with respect to iO ₂ 100 on the surface of a glass substrate. .

Therefore, the present invention relates to a water-repellent glass, which is a water-repellent glass comprising a water-repellent layer on the surface of a glass substrate having smooth or fine irregularities, wherein the water-repellent layer is It is characterized by comprising at least silica and a fluororesin, and the fluororesin has a weight ratio of 5 to 450 with respect to 100 of the silica. In contrast to the present invention, the conventional water-repellent glass (Japanese Unexamined Patent Publication No. 5-51238) has a structure in which Teflon fine particles are dispersed throughout the metal oxide phase on the glass substrate, and therefore the water repellency is sufficient. In addition, there was a problem that the hardness was insufficient and it was easily damaged. The present invention has been made in view of such conventional problems, and does not disperse the Teflon fine particles in SiO ₂ on the glass substrate, but has a configuration in which the concentration distribution of the fluororesin is continuously inclined. Therefore, it has excellent water repellency and is not easily scratched.

As the glass substrate used for the water-repellent glass of the present invention, a substrate made of commercially available soda lime glass used for vehicles, ships, aircraft, construction, etc. can be adopted. Further, it may be tempered glass, laminated glass, or mirror glass. The surface of the glass substrate may be flat, but it is more preferable that the surface has fine irregularities by hydrofluoric acid treatment or plasma etching in order to enhance the adhesion to the water repellent layer.

The water-repellent layer provided on the glass substrate is composed of at least silica and a fluororesin, and the mixing ratio of the fluororesin to silica is such that the fluororesin is silica 10.
The weight ratio to 0 is 5 to 450. If the fluororesin is less than 5 relative to silica 100, the water-repellent effect is not exerted, and if it exceeds 450, the film becomes soft and therefore 5 to 45.
Set to the range of 0. Fluorine resin is preferably silica 100
On the other hand, the weight ratio is preferably 30 to 300. The thickness of the water repellent layer in the present invention is preferably 0.01 μm or more, more preferably 0.02 to 1 μm.

Next, the present invention also relates to a method for producing the above water-repellent glass. In the method for producing the water-repellent glass of the present invention, the water-repellent layer is formed by applying a solution obtained by mixing at least a silica sol solution and fluororesin particles or a suspension of fluororesin particles onto a glass substrate and baking it. Form.

The silica sol solution used is a solution obtained by hydrolyzing and polycondensing a silicon alkoxide or a monomethyl alkoxide as a starting material. This solution may contain other metals such as alkoxides of Al, Zr and Ti, monomethylalkoxides or acetylacetonate salts and polycondensates thereof.

Preferred examples of the alcotoside or monomethylalkoxide include (monomethyl) methoxide, (monomethyl) ethoxide and (monomethyl).
Isopropoxide, (monomethyl) n-butoxide and the like, and preferred acetylacetonate salts include acetylacetonate zirconium,
Examples include titanium acetylacetonate. Examples of commercially available products of silica sol include trade name Super Cera (Dahachi Chemical Industry Co., Ltd.), Ceramica Co., Ltd. Nichiban Kenkyusho, HAS (Colcoat Co., Ltd.) and the like.

The fluororesin is a polymer mainly composed of carbon and fluorine, and includes polytetrafluoroethylene, polychlorofluoroethylene, polyvinylidene fluoride,
Examples include polyvinyl fluoride, copolymers of tetrafluoroethylene and hexafluoropropylene, tetrafluoroethylene and ethylene copolymers, tetrafluoroethylene and perfluoroalkyl vinyl ether copolymers, chlorotrifluoroethylene and ethylene copolymers, and the like. To be The fluororesin may be mixed as a powder in the silica sol solution, or may be mixed as a dispersed suspension.

As the powder of polytetrafluoroethylene, for example, a trade name of polyflon (M-12, 14, 1)
5), Lubron (L-2,5) (Daikin Industries, Ltd.)
As a powder of tetrafluoroethylene and ethylene copolymer, for example, trade name NEOFLON (ETFE) (manufactured by Daikin Industries, Ltd.), and as a suspension of polytetrafluoroethylene powder, for example, trade name Polyflon (D- 1,
D-2, D-2C), Lubron (LDW) (manufactured by Daikin Industries, Ltd.), and a suspension of a copolymer powder of tetrafluoroethylene and hexafluoropropylene is, for example, a trade name NEOFLON (ND-1, 2, 4) (manufactured by Daikin Industries, Ltd.), as a suspension of tetrafluoroethylene and perfluoroalkyl vinyl ether copolymer powder,
For example, trade name NEOFLON (AD-1, AD-2) (manufactured by Daikin Industries, Ltd.) and the like can be mentioned. The particle size of the fluororesin powder is 0.6 μm or less, preferably 0.1 μm or less.
The thickness is preferably 0.6 μm.

In the method for producing water-repellent glass of the present invention, as described above, a solution prepared by mixing at least a silica sol solution with fluororesin particles or a suspension of fluororesin particles is applied onto a glass substrate and baked to repel it. A water-repellent glass is obtained by forming a water layer, but the baking temperature of the water-repellent layer is 10
If the temperature is below 0 ° C, the hardness of the film is not sufficient, and at 500 ° C
If it exceeds 100, sufficient water repellency will not be exhibited and 100
It is preferably in the range of ˜500 ° C. As the coating method on the glass substrate, a dipping and pulling method, a spray method,
Known coating means such as a flow coating method or a spin coating method can be appropriately adopted.

[0018]

EXAMPLES Next, the present invention will be described with reference to Examples and Comparative Examples. Example 1 As shown in FIG. 1, the water-repellent glass of Example 1 comprises a glass substrate 1 and a water-repellent layer 2 laminated on the surface of the glass substrate 1 and having a thickness of 0.1 μm. There is. This water-repellent glass was formed as follows. First, as the glass substrate 1, a clear float glass substrate having a size of about 100 mm × 100 mm and a thickness of 2 mm was sequentially washed with a neutral detergent, water rinse, alcohol, dried and then wiped with acetone to obtain a coating substrate. A suspension of fluororesin particles in a silica sol solution (trade name NEOFLON ND) so that the fluororesin in the water repellent layer is 100% by weight with respect to silica.
-1 (manufactured by Daikin Industries, Ltd.) was added and mixed to prepare a solution, which was coated on the surface of the glass substrate, and 380 ° C.
Was baked for 30 minutes to form a water repellent layer 2 having a film thickness of about 0.1 μm. Thus, the water-repellent glass of Example 1 was obtained. The following tests were conducted on the obtained water-repellent glass. (Water repellency test) Measurement of contact angle to water in air (about 25 ° C) (Pencil hardness) Measurement according to JIS K 5400 (Weather resistance test) Evaluation by Super UV Condition: 60 mW / cm ² (Heat cycle test ) 80 ° C x 4H → -40 ° C x
Table 1 shows the results of the 1.5-H 10-cycle evaluation. From these results, it can be seen that the water-repellent glass obtained is hard and has excellent weather resistance, and also has excellent adhesion, so that the film is not peeled off by the heat cycle test.

Example 2 In Example 1, the glass substrate was 0.1% before the water repellent treatment.
A water-repellent glass was formed in the same manner as in Example 1 except that fine irregularities were formed on the glass surface by treatment with hydrofluoric acid for 10 minutes. Further, the evaluation of the obtained water-repellent glass was performed in the same manner as in Example 1. The evaluation results are shown in Table 1. From these results, it can be seen that the water-repellent glass obtained is hard and has excellent weather resistance, and also has excellent adhesion, so that the film does not peel off due to the heat cycle test.

Example 3 In Example 1, a suspension of fluororesin particles (trade name: Neoflon ND-1 (Daikin) in a silica sol solution was prepared such that the fluororesin in the water repellent layer was 50% by weight with respect to silica. A water-repellent glass was formed in the same manner as in Example 1 except that a solution containing Kogyo Kogyo Co., Ltd. was added and mixed, and this solution was applied to the surface of the glass substrate. The evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 1. From the results, the obtained water-repellent glass was
It can be seen that the film is hard, has excellent weather resistance, and has excellent adhesiveness, so that the film is not peeled off by the heat cycle test.

Comparative Example 1 A water-repellent glass was formed in the same manner as in Example 1 except that the water-repellent layer was entirely made of fluororesin. Further, the evaluation of the obtained water-repellent glass was performed in the same manner as in Example 1. The evaluation results are shown in Table 1. From this result, it can be seen that the water-repellent glass obtained is excellent in weather resistance but soft and has poor adhesion.

Comparative Example 2 The procedure of Example 1 was repeated, except that the water repellent layer did not contain a fluororesin and was entirely made of silica. In addition, the obtained glass was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. From this result, it was found that the obtained glass does not exhibit water repellency because it is simply a glass coated with silica.

Comparative Example 3 A water repellent glass was formed in the same manner as in Example 1 except that the fluororesin in the water repellent layer was 600% by weight with respect to silica. Further, the evaluation of the obtained water-repellent glass was performed in the same manner as in Example 1. The evaluation results are shown in Table 1. From this result, it can be seen that the water-repellent glass obtained is excellent in weather resistance but soft and has poor adhesion.

In Example 1, 1 g of heptadecatridecylfluoroalkylsilane [CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ Si (OCH ₃ ) ₃ ] and 48 g of isopropyl alcohol were used as a water repellent treatment for the washed glass substrate. 1 g of 60% nitric acid was placed in a beaker, and the mixture was thoroughly mixed and stirred at room temperature to apply a partially hydrolyzed fluoroalkylsilane solution, which was applied to about 250
A water-repellent glass was formed in the same manner as in Example 1 except that the water-repellent glass was baked at 30 ° C. for 30 minutes. Further, the evaluation of the obtained water-repellent glass was performed in the same manner as in Example 1. The evaluation results are shown in Table 1. From this result, it is understood that the water-repellent glass obtained is hard but has poor weather resistance.

[0025]

[Table 1]

[0026]

As described above, according to the water-repellent glass and the method for producing the same of the present invention, a film can be obtained inexpensively and efficiently by a simple and easy film forming means, without impairing the optical characteristics. , Water repellency, adhesion, hardness, weather resistance, etc., which can be suitably used for various glass articles such as window materials for construction or automobiles, etc. Can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a water-repellent glass prepared in Example 1.

[Explanation of symbols]

 1 glass substrate 2 water repellent layer

Claims (2)

[Claims] 1. A water-repellent glass comprising a water-repellent layer on the surface of a smooth or finely uneven glass substrate, wherein the water-repellent layer comprises at least silica and a fluororesin, and the fluororesin is contained in the silica 100. 5 to 450 by weight
A water-repellent glass characterized by being. 2. A water-repellent layer is formed by applying a solution prepared by mixing at least a silica sol solution and fluororesin particles or a suspension of fluororesin particles onto a glass substrate and baking it. Method for producing water-repellent glass.