JPH0656476A - Water repellent window glass - Google Patents

Abstract

PURPOSE:To obtain a water-repellent window glass capable of sustaining water repellency and frost repellency for a long period of time by providing the surface of a glass with a ceramic coating layer made from mixture of a ceramic sol and a fluorocompound. CONSTITUTION:The ceramic sol, dispersing a ceramic in a dispersion medium is pref. one capable of forming a ceramic coating film by heating following coating (e.g. zirconia sol). The fluorocompound, having fluorine atom(s) in the molecule is pref. one giving high water repellency when incorporated in the ceramic coating layer and also pref. a substance with high light transmissivity (e.g. a nonionic type fluorosurfactant). The ceramic sol and the fluorocompound may be mixed with each other at any mixing ratio. If necessary, this mixture is aged prior to application. For forming a coating film, the mixture is applied on the surface of a glass and then heated. When a zirconia sol is used, the mixture is heated at 200-400 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-repellent window glass which maintains a water-repellent effect for a long time.

[0002]

2. Description of the Related Art For example, in order to impart water repellency to a surface of a window glass of an automobile or the like to prevent deterioration of visibility, a method of applying a fluororesin to the glass surface has been conventionally adopted. By applying such a fluorine resin,
Water drops and dirt are less likely to adhere to the glass surface.

[0003]

However, since the conventional fluororesins have poor adhesion to glass, the life of the coating film is extremely short and the effect of imparting water repellency is short, about 3 to 7 days. .

In view of such circumstances, it is an object of the present invention to provide a water repellent window glass which has good water repellency and whose effect lasts for a long time.

[0005]

The water-repellent window glass according to the present invention which achieves the above object is characterized in that a ceramic coating layer formed of a mixture of a ceramic sol and a fluorine compound is provided on the glass surface. And

[0006]

The structure of the present invention will be described in detail below. In the present invention, the ceramic sol refers to one in which ceramics are dispersed in a dispersion medium, and a ceramic coating film can be formed by heating after coating, which forms a coating film that does not significantly impair the transparency of glass. Is preferred. As a preferred specific example, zirconia sol (including zirconia sol in the present invention) can be mentioned. Among them, an organic solvent-dispersed zirconia sol (see JP-A-3-218928) obtained by adding an organic solvent to a water-dispersed zirconia sol and substituting water for the organic solvent is particularly preferable. This is because a transparent and crystalline coating film can be formed by mixing with a fluorine compound.

In the present invention, the fluorine compound is a compound containing an elemental fluorine in the molecule, preferably a compound showing high water repellency when contained in the ceramic coating layer, and a substance having a high light-transmitting property is selected. Is good. Further, from the viewpoint of maintaining the water repellency for a long period of time, it is preferable to use one that is chemically bound to the ceramic sol by a polycondensation reaction or the like. When used with the organic solvent-dispersed zirconia sol, as a fluorine compound which undergoes a polycondensation reaction with the zirconia sol by aging, and shows good water repellency,
Nonionic fluorine-based surfactant, perfluorobenzoic acid, N- [3- (trimethoxysilyl) propyl]-
Mention may be made of N-n-propyl perfluorooctyl sulfonamide.

To form the coating film of the present invention,
The mixture may be heated after applying a mixture of the ceramic sol and the fluorine compound on the glass surface. The mixing ratio of the ceramic sol and the fluorine compound is not particularly limited as long as the effects of the present invention are exhibited, but the water repellency increases as the concentration of the fluorine compound increases, but the transparency is lost due to cloudiness or the like, Since there is a tendency for the contact angle to vary due to uneven coating and peeling to occur easily, the selection may be made within a range where such inconvenience does not occur.

The coating method is not particularly limited as long as it can be coated to have a uniform thickness, but it is preferable to employ a dipping method which can easily form a uniform film. In this method, it is possible to adjust the film thickness by adjusting the pulling rate or by repeating the coating. However, if the coating film thickness becomes thick, cloudiness may start or peeling may occur. It is preferable to select the film thickness within a range that does not cause such inconvenience. It should be noted that the coating may be carried out on both sides of the glass or on one side as required.

The heating conditions may be selected such that the ceramics are stable and the heat resistance of the fluorine compound is taken into consideration so that a good coating film can be formed. In addition, when a polycondensation reaction of ceramics and a fluorine compound is caused, it is preferable to perform aging as needed before coating. When zirconia sol is used, the heat treatment temperature is preferably about 200 ° C to 400 ° C. This is because when the temperature is lower than this, abrasion resistance tends to decrease, and when the temperature is higher, the water-repellent effect tends to decrease, both of which are not preferable. Further, considering the polycondensation reaction time of the zirconial sol and the fluorine compound, it is preferable to age the coating solution for about 24 hours after preparation.

Fluorine compounds can be easily incorporated into the ceramic coating film formed by the sol-gel method, and since the ceramic coating film has good adhesion to glass and high abrasion resistance, the water repellency is maintained for a long time. Can be held over. Further, in this case, if the ceramic and the fluorine compound are chemically bonded, the effect of further prolonging the life is exhibited.

[0012]

EXAMPLES The present invention will be described below based on examples.

Zirconial sol (manufactured by Nippon Shokubai Co., Ltd.) was mixed with the following various fluorine compounds (fluorine compound concentration 0.2 wt%, ZrO ₂ concentration 3 wt%, propylene glycol methyl ether 50 wt%, water 46.8 wt%). And then aged for 24 hours, and then coated on both surfaces of the glass by a dipping method,
Heat treatment was performed at 0 ° C. for about 2 hours. The coating by the dipping method was performed by pulling the glass vertically from the liquid surface at a speed of 0.2 mm / s to form a film having a thickness of 0.04 μm. The film thickness can be appropriately adjusted by changing the pulling rate as described above. (Fluorine Compound Used) Nonionic Fluorine Surfactant Perfluorobenzoic Acid N- [3- (trimethoxysilyl) propyl] -Nn
-Propyl perfluorooctyl sulfonamide

When the water repellency (measured by the contact angle of distilled water) and the transmittance of the coated glass were measured, the contact angle was 78 ° to 103 ° and the transmittance was around 80%. It was also found that this value was the same after the automobile windshield standard test (JIS R3212, item 3.7) and was excellent in durability. For comparison, the same measurement was carried out on uncoated glass, and the contact angle was about 20 ° and the transmittance was about 87.
%Met.

The water-repellent window glass produced in the above examples is particularly suitable for use in automobile window glass and has good water repellency over a long period of time, but of course it is also used for other purposes. It goes without saying that you can do it. Further, the coating may be applied to only one side of the glass, but when it is used for a window glass of an automobile, for example, the double-sided coating is preferable in consideration of frost repellency and prevention of adhesion of dirt.

[0016]

As described above with reference to the embodiments, the water-repellent window glass of the present invention has the fluorine compound fixed by the ceramic coating film formed by the sol-gel method, so that the water-repellent window glass has good water repellency for a long period of time. It has the effects of exhibiting frost repellency and being easy to manufacture.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shigeru Ito 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Yoichi Taniguchi 5-33-8 Shiba, Minato-ku, Tokyo Within Mitsubishi Motors Corporation (72) Inventor Kazuo Hata 1 at 992 Nishioki, Nishihama, Aboshi-ku, Himeji-shi, Hyogo Prefecture Within Japan Catalyst Co., Ltd. Inside the catalyst

Claims (3)

[Claims] 1. A water-repellent window glass characterized in that a ceramic coating layer formed of a mixture of ceramic sol and a fluorine compound is provided on the glass surface. 2. The water-repellent material according to claim 1, wherein the ceramic sol is an organic solvent-dispersed zirconia sol obtained by adding an organic solvent to a water-dispersed zirconia sol and replacing water with the organic solvent. Window glass. 3. The fluorine compound according to claim 1, wherein the fluorine compound is a nonionic fluorine-based surfactant, perfluorobenzoic acid, or N- [3- (trimethoxysilyl) propyl] -Nn-propylperfluoro. Water repellent window glass characterized by being octyl sulfonamide.