JPH0726751U - Water repellent performance evaluation device - Google Patents

Abstract

(57) [Summary] [Object] To provide a measuring device capable of accurately forming water droplets, inclining a sample at a low speed, and accurately reading the sample inclination angle. [Structure] A sample holder, a shaft attached to the sample holder and connected to the shaft so that the surface of the plate-like sample held by the sample holder can be tilted by rotation.
A drive means for rotating the shaft to gradually tilt the sample, a sample tilt angle reading means for measuring the tilt angle of the sample, and a water supply port at the lower end above the sample position. The water repellent performance evaluation apparatus is provided with a water tank and water supply means capable of forming water droplets on the surface of the sample.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a water repellent performance evaluation device, and more particularly to a device for evaluating water repellent performance by measuring a falling angle of a water drop on the surface of a plate-shaped sample.

[0002]

[Prior art]

 By imparting water repellency to the surface of a transparent plate-like article such as a glass plate, it becomes difficult for water droplets containing pollutant components to adhere to and remain on the glass surface, thus providing the effect of preventing glass contamination and burning. By using this water-repellent glass for windshields and side windows of automobiles, rainwater that adheres to the surface during rainy weather can be easily blown off by wind pressure, ensuring the driver's field of view and ensuring safety. improves.

The water repellency of a solid plate-like sample surface such as a water-repellent glass plate can be evaluated by placing a water drop on the sample surface kept horizontally and measuring the contact angle of the water drop. Dynamic water repellency is achieved by placing water droplets on the surface of a sample that is kept horizontal and gradually inclining the sample so that the water droplets 15 attached to the surface of the sample 11 start rolling as shown in FIG. It can be evaluated by measuring the angle a formed between the sample surface and the horizontal plane. This angle a is defined as a water drop falling angle. It can be said that the smaller the water drop rolling angle a, that is, the smaller the water drop falling angle a, the higher the water repellency of the sample. Conventionally, the water drop angle is measured by visually measuring the angle at which a person forms a water drop using a syringe, tilts this sample by hand, and rolls it out with a protractor.

[0004]

[Problems to be solved by the device]

 However, this measurement of the water drop angle has the following problems.

[0005] When the size (weight) of a water drop increases or decreases, the water drop angle decreases or increases, respectively. Especially, in the case of a water drop having a weight of less than 10 mg, the water drop is hard to be affected by gravity and the water drop does not roll. It becomes difficult to measure the water drop angle, and if the weight exceeds 200 mg, the effect of gravity is too great and the water drops are deformed into a water-like flow, resulting in extremely small values of the water drop angle. Therefore, it is necessary to form a water droplet with a weight within the range of 10 mg to 200 mg on the sample surface with a precision as high as possible, for example, within a precision of about ± 1%. If this is not possible, the variation in the water drop angle value for each measurement will be large, and the reproducibility of the measurement, that is, the accuracy will be impaired. It is difficult to form such highly accurate water droplets by hand using a tool such as a syringe.

The sample should be tilted at a low speed of 10 ° / min or less, and if it is tilted at a speed higher than this, it tilts to a higher angle when it is detected that a water droplet has started rolling, and It is determined that the water drop angle is higher than the value. It is difficult to tilt such a low-speed sample manually.

Although it is necessary to accurately read the falling angle, it is difficult to visually read it by using a protractor or the like.

As described above, it is difficult to measure the drop angle of water drop with high precision due to the combination of such factors.

The present invention focuses on the above-mentioned problems in the measurement of the water drop angle, and enables the water droplet to be formed accurately, the sample to be tilted at a low speed, and the sample tilt angle to be accurately read. The proposed measuring device is proposed.

[0010]

[Means for Solving the Problems]

 That is, the water droplet falling angle measuring device of the present invention comprises a shaft attached to the sample holder and a shaft attached to the sample holder so that the surface of the plate-shaped sample held in the sample holder can be tilted by the rotation of the sample holder. A driving unit that is connected and rotates the shaft to gradually tilt the sample, a sample tilt angle reading unit that measures the tilt angle of the sample, and a water sample at the lower end above the sample position. The water repellent performance evaluation apparatus is provided with a water tank having a water supply port, and water supply means capable of forming water droplets on the surface of the sample.

The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of the device of the present invention. In the figure, 1 is a sample holder, 2 is a glass plate sample held by the sample holder 1, 3 is a shaft attached to the sample holder, and by rotating the shaft 3, the sample holder 1 The surface of the held sample 2 is inclined. The shaft body 3 is preferably attached to the sample holder such that its axis is parallel to the surface of the glass plate sample held in the sample holder 1. Reference numeral 4 is a driving means such as a motor with a speed reducer, which is connected to the shaft body 2, and rotates the shaft body 3 to gradually incline the sample 2. Reference numeral 5 is a sample tilt angle reading means for measuring the tilt angle of the sample 2, and is, for example, an encoder attached to the shaft body 3. 6 is a water supply means, and for example, a microdispenser manufactured by EFD can be used. The water tank 7 is provided above the sample 2 position, and the water supply port 8 at the lower end of the water tank 7 is located approximately 1 to 5 cm above the sample surface so that water droplets can be formed on the sample surface. A conduit tube 9 is connected to the upper end of the water tank 7 so that compressed air whose pressure is adjusted applies pressure to the water in the water tank 7 through this conduit 9. Then, when a button (not shown) is pressed, the valve 10 provided in the middle of the conduit 9 is opened for a certain period of time and the compressed air acts so that a certain amount of water is supplied from the water supply port 7 onto the sample 2 and its surface Water droplets are formed on the. The weight of water droplets can be adjusted by changing the set pressure value of compressed air.

As the driving means 5, for example, a motor in which a reduction gear is connected, for example, a combination of a speed control motor (manufactured by Oriental Motor Co., Ltd.) and a gear head is used. As the sample tilt angle reading means 5, for example, an apparatus that optically reads the rotation angle of the shaft body (for example, an encoder manufactured by OMRON Corporation) is used, but another method, for example, the surface of the sample and water droplets is used. Alternatively, a method may be used in which light is made incident on a surface portion where is not placed and the change in angle of reflected light due to the tilt of the sample is measured.

[0013]

【Example】

 A motor (40 watts, PSH540-401P manufactured by Oriental Motor Co., Ltd.) and five gear heads (rotation magnification: 5 times, 5GN10XK manufactured by the same company) were connected in series to a driving means, which was connected to a sample holder via a rotary shaft. There is. A 10 cm × 10 cm glass plate sample coated with a water repellent and dried is held in a sample holder so that the surface of the sample is horizontal. The rotation of the motor is decelerated and the rotating shaft rotates about once per hour. Water droplets were formed on the surface of this sample using a micro dispenser 1500XL type manufactured by EFD. The weight of this water drop was measured with a balance. 50. It was 2 mg. The motor was rotated to tilt the sample from the horizontal state at a speed of 2 ° / min. Encoder (Omron Co., Ltd. encoder E6D-CWZ2C2000PPS) with the tilt angle of the sample from the horizontal state (water droplet falling angle) attached to the rotating shaft by observing the moment when the water droplet starts rolling with the naked eye. It was 25.3 ° when read from the rotation angle of the rotating shaft measured in 1. The same test was repeated 4 times for the same sample, and a total of 5 times was measured (automatic method).

For comparison, water droplets were formed on the same sample using a syringe, the axis of rotation was rotated by hand, the water droplet was stopped at the moment it started rolling, and the angle between the sample and the horizontal surface was measured using a protractor. The same measurement was performed 5 times by the reading method. (Manual method) The water drop weight and the falling angle value in the above two methods are shown in the table.

[0015]

[Table 1] Table ----------------------- Example --Comparison Example (Automatic method) (Manual method) Weight Falling angle Water drop weight Falling angle (mg) (°) (mg) (°) −−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 1 50.2 25.3 48.1 24.2 2 50.0 25.1 52.0 23.5 3 49.9 25.3 49.9 25.5 4 49.7 25.5 47.5 26. 8 5 50.3 25.0 51.1 24.3 −−−−−−−−−−−−−−−−−−−−−−−−−−−−− Example (automatic method) Is more reproducible in both the water drop weight and the measured fall angle than the comparative example (manual method). Further, in the manual method, there is no correlation between the measured value of the falling angle and the weight of the water droplet, and therefore it is difficult to correct the falling angle due to the variation in the weight of the water droplet. This indicates that in the manual method, variations in water drop weight, variations in sample tilting speed, and variations in sample tilting angle readings cause the falling angle measurement values to vary.

[0016]

[Effect of device]

 According to the present invention, it is possible to reproducibly form water droplets of a size affected by proper gravity, and since the sample is tilted at a speed of 10 ° / min or less, it is possible to detect the water droplets when the water droplet rolling is detected. Is not tilted at an angle larger than that, and the sample tilt angle can be read with high accuracy. Therefore, it is possible to accurately measure the water drop angle.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the device of the present invention.

FIG. 2 is a cross-sectional view showing the concept of a water drop falling angle.

[Explanation of symbols]

 1 ・ ・ Sample holder 2 ・ ・ Glass plate sample 3 ・ ・ Shaft body 4 ・ ・ Driving means 5 ・ ・ Inclination angle reading means 6 ・ ・ Water supply means 7 ・ ・ Water tank 8 ・ ・ Water supply port 9 ・ ・ Conduit 10 ..Valve a..Water drop falling angle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiishi Mitani 3-5-11 Doshumachi, Chuo-ku, Osaka Japan Sheet Glass Co., Ltd. (72) Inventor Yasuo Masuya 3-5-11, Doshomachi, Chuo-ku, Osaka No. Nippon Sheet Glass Co., Ltd. (72) Inventor Shunsuke Yoshitaka 3-5-11 Doshomachi, Chuo-ku, Osaka City Inside Nippon Sheet Glass Co., Ltd.

Claims (2)

[Scope of utility model registration request] 1. A sample holder, a shaft attached to the sample holder, connected to the shaft, and rotating the shaft so that the surface of the plate-shaped sample held by the sample holder can be tilted by rotation. A driving means for moving and gradually inclining the sample, a sample inclination angle reading means for measuring the inclination angle of the sample, and a water tank having a water supply port at the lower end are provided above the sample position. And a water repellent performance evaluation apparatus having water supply means capable of forming water droplets on the surface of the sample. 2. The driving means is capable of tilting the surface of the plate-shaped sample held by the sample holder at a speed of 10 ° / min or less, and the sample tilt angle reading means is used for tilting the sample. The angle can be read with an accuracy within ± 0.5 °, and the water supply means has a range of 10 mg to 200 mg on the surface of the sample ± 1.
The water-repellent performance evaluation device according to claim 1, which is capable of forming water droplets with an accuracy of within%.