JPH1129856A - Water-repellent surface and its formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve points of problem in that a base stock for a member to be treated is confined with the roughened surface forming method by the conventional etching and sandblasting, and simultaneously, a uniform roughened surface is not obtd. and as much improvement of performance as expected is not obtd. when more water-repellent property is improved by roughening the surface of the member to be treated. SOLUTION: The forming method for the water-repellent surface 1 is to form a particle film 3 on the surface 2a of the member 2 to be treated by executing the vacuum-deposition of tin under the state where the temp. of this member 2 to be treated is set at <=100 deg.C prior to the formation of the water- repellent coating film, and thereafter, the formation of the water-repellent coating film 4 is executed. Consequently, fine and uniform roughened surface is easily formed on the surface of the member 2 to be treated, thereby remarkably improving the water-repellent property, and simultaneously, forming the particle film 3 at low temp. and not selecting the base stock for the member 2 to be treated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a water-repellent surface, in which a rear-view mirror provided outside a car, for example, is mirror-finished so as not to lose visibility due to water droplets adhering during rainfall. Things.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show an example of a conventional method for forming a water-repellent surface. First, FIG. 4 shows the surface of a member to be processed 90, such as metal, glass or resin. The water-repellent coating 91 is formed of a silicone-based member or a fluorine-based member which is a water-repellent member. As a specific means for forming the water-repellent coating 91, the means disclosed in Japanese Patent Publication No. Hei 3-20465 by the same applicant can be applied.

FIG. 5 shows a member 80 to be processed.
Surface 80a is subjected to an etching process or a sandblasting process to obtain a rough surface having fine irregularities.
A water-repellent coating 81 is formed on the substrate 0a using the same water-repellent member as described above (see Japanese Patent Publication No. 15179/1992). Therefore, unlike the conventional example shown in FIG. 4, it is necessary to select in advance a member capable of performing the roughening treatment, such as a member that can be subjected to an etching process, for example, the member to be processed 80. .

[0004] By doing so, in the water-repellent coating 91 shown in FIG. 4, for example, when the water-repellent member is a fluorine-based member, the contact angle is approximately 110 °, which matches the characteristics of the selected water-repellent member. Water repellency is obtained, and in the water repellent coating 81 shown in FIG.
By making a a rough surface, the surface of the water-repellent coating 81 is also roughened, the apparent contact angle is increased, and water repellency (super water repellency) exceeding the characteristics of the water repellent member is obtained.

[0005]

However, in the above-described conventional method for forming a water-repellent surface, particularly in a method for obtaining super-water-repellency (see FIG. 5), the member to be processed 80 is not required.
When the surface 80a is roughened, an etching process is performed.
First, the material to be processed is limited by a material which is difficult to be etched and sandblasted, such as a resin, because the material to be processed 80 is not suitable. Point has arisen.

Secondly, the rough surface formed by the above-mentioned treatment is not uniform in roughness and the apparent contact angle does not increase as much as expected. In the case of, the contact angle is 120 ° to 130 °, the performance is improved only up to about 10 ° to 20 °, the effect of roughening is not so much exhibited, and only unsatisfactory results in performance are obtained. There were points, and the solution of these points was an issue.

[0007]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, a water-repellent surface formed by forming a water-repellent film on a surface of a member to be processed by a water-repellent member is provided. In the forming method, prior to the formation of the water-repellent film on the surface of the member to be processed, vacuum deposition of tin is performed in a state where the temperature of the member to be processed is set to 100 ° C. or less. An object of the present invention is to solve the problem by providing a method for forming a water-repellent surface, in which film formation is performed.

[0008]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 shows the first step of the method for forming a water-repellent surface according to the present invention. In the present invention, what is indicated by reference numeral 2 is a member to be processed. Any material can be selected, such as metal, glass, and resin.

Then, tin (Sn) is vacuum-deposited on the surface 2a of the member to be processed 2 on which the water-repellent surface is to be formed. At this time, if the temperature of the member to be processed 2 is kept at 100 ° C. or less, tin adheres to the surface 2a as particles instead of forming a thin film. The aggregated particle film 3 is obtained.

FIG. 2 schematically shows the structure of the particle film 3. In the figure, reference numeral 3 a denotes individual tin particles 3 a constituting the particle film 3. The figure is a diagram of an image magnified 10,000 times by a scanning electron microscope (SEM). According to the observation results, the particle diameter of the tin particles 3a is 100 nm to 1.5 μm. It is recognized that the tin particles 3a having a diameter of about 1 μm are uniformly dispersed.

After the particle film 3 is formed as described above, a water-repellent film 4 is formed by a water-repellent member such as a silicone-based member or a fluorine-based member. As described above, the plasma polymerization method disclosed in Japanese Patent Publication No. Hei 3-20465 by the same applicant may be used. By the above steps, a desired water-repellent surface 1 having a water-repellent surface 2a of the member to be processed 2 can be obtained as shown in FIG.

Next, the function and effect of the water-repellent surface 1 formed by the above-described method of the present invention will be described.
By providing the particle film 3 with tin on the surface 2a of the member 2 to be processed according to the present invention, the surface 2a of the member 2 to be processed has minute irregularities (about 1 μm) in an extremely uniform state.
Is obtained.

Accordingly, the surface 4a of the water-repellent coating 4 provided to cover the particle film 3 is also a rough surface in an extremely uniform state, and this uniform state covers the entire surface 4a of the water-repellent coating 4. . Thus, the obtained water-repellent surface 1 increases the apparent contact angle with respect to water droplets and improves water repellency due to the above rough surface. However, since the entire surface is a uniform rough surface, the water repellent surface 1 has a rough surface as in the conventional example. The water repellency is remarkably improved without causing a decrease due to the non-uniformity.

As a result of the above-described trial production and examination by the inventor for realizing the present invention, if a fluorine-based member is adopted as the water-repellent member and a rough surface is formed by conventional etching or sandblasting, the fluorine-containing member is used. The characteristic of the contact angle of 110 ° inherent in the system member is only 10
However, according to the present invention, it was confirmed that the contact angle was improved by 150 ° or more and 40 ° or more.

The above-mentioned vacuum deposition of tin is performed by setting the temperature of the member to be processed 2 to 100 ° C. or less.
The present invention can be applied to a resin member having relatively low heat resistance, that is, almost all materials required to form the water-repellent surface 1 without selecting the material of the member 2 to be processed. This makes it possible to meet demand, and at this time, there is no difference in effect due to the difference in material.

[0016]

As described above, according to the present invention, prior to the formation of the water-repellent coating on the surface of the member to be treated, tin is vacuum-deposited at a temperature of the member to be treated of 100 ° C. or less. The method of forming the water-repellent surface, on which the water-repellent film is formed after that, makes it possible to easily form a fine and uniform rough surface on the surface of the member to be processed,
This is an extremely excellent effect of dramatically improving the water repellency of the water repellent film formed thereafter.

Since the rough surface is formed by vacuum evaporation of tin, there is no difference in the uniformity of the rough surface obtained due to the properties of the member to be processed. Since it is carried out at the following temperature, it can be carried out on almost all materials requiring water repellency, which also has the effect of improving versatility for the method of forming the water repellent surface. is there.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first step of a method for forming a water-repellent surface according to the present invention.

FIG. 2 is an explanatory view schematically showing a surface state of a member to be processed obtained by depositing tin.

FIG. 3 is a sectional view showing a water-repellent surface similarly obtained by the forming method according to the present invention.

FIG. 4 is a sectional view showing a conventional example.

FIG. 5 is a sectional view showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Water-repellent surface 2 ... Member to be treated 2a ... Surface of member to be treated 3 ... Particle film 3a ... Tin particles 4 ... Water-repellent coating 4a ... Surface of water-repellent coating

Claims (2)

[Claims] 1. A method for forming a water-repellent surface, comprising forming a water-repellent coating on a surface of a member to be processed by a water-repellent member,
Prior to the formation of the water-repellent film on the surface of the member to be processed, vacuum deposition of tin is performed in a state where the temperature of the member to be processed is set to 100 ° C. or less, and then the film formation of the water-repellent film is performed. A method for forming a water-repellent surface, comprising: 2. A water-repellent surface in which a water-repellent film is formed on a surface of a member to be processed by a water-repellent member, wherein a temperature of the member to be processed is set to 100 ° C. or less on the surface of the member to be processed. A water repellent surface, wherein a particle film obtained by performing vacuum deposition of tin is formed, and the water repellent film is provided to cover the particle film.