JPH0748146A - Production of water repellent glass - Google Patents

Abstract

PURPOSE:To produce rigid water-repellent glass excellent in adhesiveness and weather resistance. CONSTITUTION:A solution obtained by at least mixing a silica sol solution with a suspension of fluororesin particles or fluororesin particles is applied onto the surface of a glass substrate 1 and the coating is preliminarily baked at a temperature not lower than 100 deg.C and not higher than a melting point of a fluororesin and then, the coating is baked at a temperature not lower than the melting point and not higher than the decomposition temperature of the fluororesin to form a water-repellent layer 2.

Description

Detailed Description of the Invention

[0001]

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

[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.

Various silane compounds containing a polyfluoroalkyl group (Rf group) to be applied onto a material such as glass have been proposed so far in order to impart water repellency to the material such as glass. For example, JP-A-58-122979. Issue 58-12
9082, 58-142958, 58-147.
No. 483, No. 58-172242, No. 58-1722
No. 43, No. 58-172244, No. 58-17224.
5, No. 58-172246, No. 58-190840
No. 58-223634 and the like.

Further, for example, Japanese Unexamined Patent Publication (Kokai) No. 58-167448 discloses a glass having a low reflectance, and a thin film having a thickness of 1 μm or less, which is made of a polyfluoroalkyl group-containing silane compound or a partially hydrolyzed condensate of the compound, is formed. It has been disclosed that by forming it on the glass surface, it has low reflectance and water and oil repellency without impairing the transparency and the like.

However, such a conventional water repellent treatment method has a problem that the water repellent glass obtained in the durability and weather resistance tests deteriorates in water repellency in a relatively short time. . Furthermore, as excellent in weather resistance,
Although there is a glass coated with Teflon, 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 material comprising both a polymer of an organosilicon compound having a siloxane bond as an adhesive component on a glass substrate and a polymer of a fluorine compound as a water-repellent component. Although a water-repellent treated glass having a coating film is described, there is a problem that it is easily scratched because the surface of the glass has a composition containing all or a relatively large amount of a water-repellent component polymer.

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 are problems such as not being able to do it.

Further, in Japanese Patent Laid-Open No. 5-51238,
A water-repellent glass provided with a metal oxide phase on a glass substrate and a water-repellent layer in which Teflon fine particles are dispersed in the metal oxide phase is disclosed. Teflon is contained in the metal oxide phase on the glass substrate. Since the fine particles are dispersed throughout, the water repellency is not sufficient, the hardness is insufficient, and there is a problem in that it is easily scratched.

[0009]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for producing a hard and water-repellent glass having excellent adhesion and weather resistance.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, in which a solution prepared by mixing at least a silica sol solution with fluororesin particles or a suspension of fluororesin particles is used as a glass solution. When manufacturing a water-repellent glass by coating and baking on a substrate surface, pre-baking is performed at a temperature of 100 ° C. or higher and a melting point of the fluororesin or lower, and then main baking is performed at a melting point of the fluororesin or higher and a decomposition temperature or lower. The present invention relates to a method for producing water-repellent glass, which comprises providing a water-repellent layer.

In the above-described method for producing the water-repellent glass of the present invention, the Teflon fine particles are not dispersed in SiO ₂ on the glass substrate but the Teflon concentration distribution is continuously inclined. It has excellent characteristics and is not easily scratched.

Specifically, it is composed of at least SiO ₂ and a fluororesin, and the fluororesin is 5 to 450% by weight, preferably 30 to 300% by weight based on 100% by weight of the SiO _2.
By producing a water-repellent glass by a two-step firing of pre-baking and main baking so that the water-repellent layer, which is% by weight, can be formed on the glass surface by controlling the concentration distribution of the fluororesin,
The above object is achieved.

The term "two-step firing" as used herein means that when the glass is coated and baked on a glass surface, it is prebaked at a temperature lower than the melting point of the fluororesin and at a temperature at which SiO ₂ is hardened. This is a method in which most of the bleeding is prevented from bleeding to the surface layer, and then main baking is performed at a temperature equal to or higher than the melting point of the fluororesin to control the concentration distribution of the fluororesin so that the water repellency and abrasion resistance are excellent.

As the glass substrate, commercially available soda lime glass used for vehicles, ships, aircraft, construction, etc. can be adopted. Also, tempered glass,
It may be laminated glass or mirror glass. The surface of the glass substrate may be flat, but in order to enhance the adhesion to the water repellent layer, the surface may be finely rugged by hydrofluoric acid treatment or plasma etching. The 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 glass and baking it by two-step firing.

As the silica sol solution, a solution obtained by hydrolyzing and polycondensing a silicon alkoxide or a monomethyl alkoxide as a starting material is used. 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 alkoxide or monomethyl alkoxide include (monomethyl) methoxide, (monomethyl) ethoxide and (monomethyl).
Examples thereof include isopropoxide and (monomethyl) n-butoxide, and preferable examples of the acetylacetonate salt include acetylzirconium and titanium acetylacetonate.

Commercially available products of silica sol are trade names Super Cera (manufactured by Daihachi Chemical Industry Co., Ltd.), Ceramica (manufactured by Nichiban Kenkyusho), Colcoat HAS (manufactured by Colcoat Co., Ltd.), Atron (manufactured by Nippon Soda Co., Ltd.). ), CGS-D1-0600
(Manufactured by Chisso 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, trade name Polyflon (M-12, 14, 1) is used.
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 of polyflon (D- 1,
D-2, D-2C), Lubron (LDW) (manufactured by Daikin Industries, Ltd.), AD1, AD2, AD660, AD63.
9 (manufactured by Asahi IC Fluoropolymers Co., Ltd.), and a suspension of a tetrafluoroethylene / hexafluoropropylene copolymer powder is, for example, trade name NEOFLON (ND-1, 2, 4) (Daikin Industries Co., Ltd. )), A suspension of tetrafluoroethylene and a perfluoroalkyl vinyl ether copolymer powder, for example, trade name NEOFLON (AD-1, AD-2) (Daikin Industries, Ltd.)
Made) etc.

The particle size of the fluorine resin powder is 0.6 μm.
m or less, preferably 0.1 to 0.6 μm.

If the mixing ratio of the fluororesin to silica is less than 5% by weight, the effect of water repellency is not exerted, and if it exceeds 450% by weight, the film becomes soft, so that it is 5 to 5.
It is preferably in the range of 450% by weight. More preferably, it is 30 to 300% by weight.

The thickness of the water repellent layer in the present invention is 0.01
The thickness is not less than μm, preferably 0.02 to 1 μm.

The baking temperature of the water repellent layer is 10 in pre-baking.
If the temperature is lower than 0 ° C, the hardness of the film is not sufficient, and the temperature is preferably 150 ° C or higher, and the upper limit of the temperature is the melting temperature of the fluororesin or lower. Next, in the main firing, above the melting temperature of the fluororesin,
Further, if the temperature exceeds the thermal decomposition temperature of the fluororesin, sufficient water repellency will not be exhibited, so it is preferable to set the temperature below the decomposition temperature. Table 1 shows melting temperatures and thermal decomposition temperatures of various fluororesins.

[0024]

[Table 1]

As a method of coating the glass, known coating means such as a dipping / pulling method, a spraying method, a flow coating method or a spin coating method can be appropriately adopted.

[0026]

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 about 0.4 μm. ing. This water-repellent glass is formed as follows. First, the glass substrate 1 has a size of about 100 mm × 10.
A clear float glass substrate having a thickness of 0 mm and a thickness of about 2 mm was sequentially washed with a neutral detergent, rinsed with water and 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-1 (melting point of fluororesin 270 ° C.), (Daikin Industries ( (Manufactured by K.K.) was added and mixed to prepare a solution, which was applied to the surface of the glass substrate and pre-baked at 250 ° C. for 30 minutes, followed by main baking treatment at 380 ° C. for 30 minutes to give a film thickness of about 0. A water-repellent layer 2 having a thickness of 4 μm was formed in this manner to form the water-repellent glass of Example 1. The obtained water-repellent glass was subjected to the following test: (Water-repellent test) Atmosphere (about 25) The contact angle with respect to water was measured at (° C.) (Wiper sliding durability test) The sliding durability was evaluated by a wet wiper blade for automobiles Test condition: About 100,000 times continuously under a load of about 100 to 200 g ( 1 round trip Performs sliding), was visually evaluated (measured according to pencil hardness) JIS K 5400 (evaluated by the weathering test) Super UV ^{conditions:... 60mW / cm 2} ( heat cycle test) 80 ° C. × 4H → -40 ° C ×
Table 2 shows the results of the 1.5H 10-cycle evaluation. From this result, the water-repellent glass obtained is hard and has excellent weather resistance, and also has excellent water repellency even after the friction and abrasion test, and since it has excellent adhesiveness, the film does not peel off by the heat cycle test. I found out that

Example 2 In Example 1, the glass substrate was treated with 0.1% before water repellent treatment.
A water-repellent glass was produced 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 2. From this result, the obtained water-repellent glass is hard and excellent in weather resistance,
It was found that even after the friction and wear test, the film had excellent water repellency and excellent adhesion, so that the film did not peel off by the heat cycle test.

Example 3 A water-repellent glass was produced in the same manner as in Example 1 except that the pre-baking temperature was 240 ° C.
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 2. From this result, the water-repellent glass obtained is hard and has excellent weather resistance, and also has excellent water repellency even after the friction and abrasion test, and since it has excellent adhesiveness, the film does not peel off by the heat cycle test. I found out that

Example 4 A water-repellent glass was produced in the same manner as in Example 1 except that the prebaking temperature was 260 ° C.
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 2. From this result, the water-repellent glass obtained is hard and has excellent weather resistance, and also has excellent water repellency even after the friction and abrasion test, and since it has excellent adhesiveness, the film does not peel off by the heat cycle test. I found out that

Example 5 A water-repellent glass was produced in the same manner as in Example 1 except that the prebaking temperature was 230 ° C.
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 2. From these results, the water-repellent glass obtained was excellent in weather resistance, but the contact angle showing water repellency after the friction and abrasion test was 90 °, which is inferior to the water-repellent glasses of Examples 1 to 4 above. It was found that the film did not peel off due to the heat cycle test because of its excellent adhesion.

Example 6 In Example 1, except that as a suspension of fluororesin particles, a solution in which Neoflon ND-4 (melting point of fluororesin 270 ° C., manufactured by Daikin Industries, Ltd.) was added and mixed, was used. A water-repellent glass was produced in the same manner as in Example 1. The obtained water-repellent glass was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2. From these results, the obtained repellency was measured. It was found that the water-based glass is hard and has excellent weather resistance, has excellent water repellency even after the friction and wear test, 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 produced in the same manner as in Example 1 except that the prebaking temperature was 290 ° C.
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 2. From these results, the water-repellent glass obtained was excellent in weather resistance, but the contact angle representing water repellency after the friction and wear test was 70 °, which is inferior to the water-repellent glasses of Examples 1 to 6 above. It was found that the film did not peel off by the heat cycle test because of its excellent adhesion.

Comparative Example 2 In Example 1, the firing temperature was set to 3 without pre-firing.
A water-repellent glass was produced in the same manner as in Example 1 except that the temperature was 80 ° C. and the baking was performed 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 2. From this result, the obtained water repellent gas is
Although it is excellent in weather resistance, the contact angle showing water repellency after the friction and wear test is 70 ° or less, which is inferior to the water repellent glasses of Examples 1 to 6 above, but excellent in adhesiveness, and therefore a heat cycle test is conducted. It was found that the film did not peel off.

Comparative Example 3 A water-repellent glass was produced in the same manner as in Example 1 except that the pre-baking temperature was 60 ° C. 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 2. From this result, although the obtained water-repellent glass is excellent in weather resistance, the contact angle showing water repellency after the friction and wear test is 70 °, and the above-mentioned Example 1 is used.
It was found that the film was inferior to the water-repellent glass of Nos. 6 to 6, but did not peel off by the heat cycle test because of its excellent adhesion.

Comparative Example 4 In Example 1, the fluororesin was 3% by weight based on silica.
A water repellent glass was manufactured in the same manner as in Example 1 except that the above was adopted. 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 2. From this result, the obtained water-repellent glass had an initial contact angle of 30 °.
And the contact angle showing water repellency after the friction and wear test is 25 °
It was markedly inferior to the water-repellent glasses of Examples 1 to 6 and could not be used for practical use.

Comparative Example 5 A water-repellent glass was produced in the same manner as in Example 1 except that the fluororesin was 500% 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 2. From these results, the obtained water-repellent glass had an initial contact angle of 1
Although it is as good as 10 °, the pencil hardness is as low as 2H, the contact angle showing the water repellency after the friction and wear test is 60 °, and the adhesion is poor, so that the film peels due to the heat cycle test. It was significantly inferior to the water-repellent glasses of Examples 1 to 6 and could not be used in practice.

[0037]

[Table 2]

[0038]

As described above, according to the method for producing water-repellent glass of the present invention, a solution obtained by mixing a silica sol solution with fluororesin particles or a suspension of fluororesin particles is applied onto the glass surface. When applied and baked, by pre-baking at a temperature lower than the melting point of the fluororesin and a temperature at which SiO ₂ is hardened, most of the melted fluororesin bleeds to the surface layer, and the particles of the fluororesin melt. It is possible to prevent the particles from being deposited and coarsen, and then to perform main firing at a temperature equal to or higher than the melting point of the fluororesin so that the distribution of the fluororesin can be controlled to have excellent water repellency and abrasion resistance.

In the method for producing water-repellent glass of the present invention, a coating can be easily and inexpensively and efficiently obtained by a simple and easy film forming means, and water repellency, adhesion, hardness and weather resistance can be obtained without impairing optical characteristics. As a result, it is possible to provide a useful water-repellent glass that can be suitably used for various glass articles and the like such as window materials for construction or automobiles.

[Brief description of drawings]

FIG. 1 is a side view of a water-repellent glass of Example 1.

[Explanation of symbols]

 1 glass substrate 2 water repellent layer

Claims (2)

[Claims] 1. When manufacturing a water-repellent glass 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 surface and baking the solution, a baking temperature of 100 is used. A method for producing a water-repellent glass, comprising pre-baking at a temperature of not less than 0 ° C and not more than the melting point of a fluororesin, and then performing main baking at a temperature not less than the melting point of the fluororesin and not more than the decomposition temperature to provide a water-repellent layer. 2. A solution prepared by mixing at least a silica sol solution with fluororesin particles or a suspension of fluororesin particles, wherein the fluororesin is 5 to 450% by weight, preferably 30 to 100% by weight of SiO _2. The method for producing water-repellent glass according to claim 1, wherein a solution containing 300% by weight is used.