JP2002114538A - Functional member having liquid droplet removing function and method for removing liquid droplet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a functional member having an enhanced water droplet removing effect on a high strength practical water-repellent surface having excellent wear resistance by freely controlling and removing water droplets on the water-repellent surface with an electric field, and to provide a method for removing liquid droplets. SOLUTION: The functional member is a dielectric in which plural electrodes have been disposed so as to apply an electric field to the surface of the dielectric subjected to water slipping treatment and has a function to remove liquid droplets on the surface by applying voltage between the electrodes. In the method for removing liquid droplets, an electric field is applied to the surface of the dielectric subjected to water slipping treatment to remove liquid droplets on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a functional member having a droplet removing function and a droplet removing method, and more particularly to a droplet removing method capable of removing droplets on a surface of glass or a mirror by applying an electric field. The present invention relates to a functional member having a function and a droplet removing method.

[0002]

2. Description of the Related Art As a conventional method for preventing droplets such as water droplets on a glass surface or a mirror surface, an ultrasonic wave is applied to the surface to shake it off, or a water repellent such as fluorine or silicone is coated on the surface. In many cases, a method of increasing the contact angle with water to make water less likely to adhere is employed. In the former method, there is an example in which a mechanism for applying an ultrasonic wave to the mirror surface of the automatic mirror is employed. However, there is a problem that the mechanism is complicated, the cost is high, and the effect is not sufficient. Further, the latter method of coating with a water repellent is often performed, but the effect is not always sufficient on a windshield of an automobile or the like, and there is a problem that water drops do not drop particularly at a low speed running.

Recently, in addition to these techniques, technical development of a super-water-repellent surface having a water contact angle of 150 ° or more, which is composed of a water-repellent surface with a controlled structure, has been developed, and is expected to be applied to water droplet prevention applications. However, this technique has a problem that the film strength is weak due to a special surface structure, and it cannot withstand friction and wear in applications such as a windshield.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a water-repellent surface having a high strength and excellent abrasion resistance by freely controlling and removing water-drops on the water-repellent surface. The purpose is to enhance the removal effect.

Further, the present invention is not only related to relatively large water droplets such as raindrops, but also removes minute water droplets which cause fogging by using an electric field, so that the fogging of mirrors and glass can be instantaneously removed. In principle, it is also possible to remove.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, a functional member according to the present invention is a dielectric in which a plurality of electrodes are arranged so that an electric field is applied near a surface thereof. Then, the surface of the dielectric material is subjected to a water-sliding treatment, and a voltage is applied to the electrode to remove the liquid droplets on the surface.

In the functional member having the function of removing liquid droplets, the falling angle on the surface of the dielectric material subjected to the water-sliding treatment is preferably 30 ° or less. Further, it is preferable that the dielectric material subjected to the water-sliding treatment is transparent.

[0008] The droplet removing method according to the present invention comprises a method comprising applying an electric field to a dielectric surface subjected to a water-sliding treatment to remove droplets on the surface.

Further, a droplet removing method according to the present invention comprises a method characterized in that a voltage is applied to the above-mentioned functional member to remove a droplet on the surface thereof.

In these droplet removing methods, the frequency of the applied partial pressure is preferably 0.01 Hz or more and 100 Hz or less.

Such a droplet removing method is particularly suitable, for example, as a drip-proof method for glass or a drip-proof method for mirrors.

The present invention has been completed based on the following technical concept. That is, the electrostatic force acting on a water droplet includes a Coulomb force acting on a charged water droplet and a gradient force acting on a dielectric substance located in an uneven electric field (see the following formula 1). Means for applying an electric field for making these work can be achieved by providing an electrode inside the vicinity of the surface of the dielectric to be prevented from fogging and applying a predetermined voltage thereto. It is also possible to arrange electrodes in an external space near the surface of the dielectric.

F = ρ _t E−1 / 2E ² {ε + 1/2} [E ² (dε / dρ _m ) ρ _m ] (1) where, ρ _t : true charge (C / m ³ ) ε: dielectric Rate ρ _m : Density (kg / m ³ ) ρ _t E: Coulomb force −１ ／ E ² ∇ε: Force acting where there is unequal permittivity 1/2 [E ² (dε / dρ _m ) ρ _m ]: Electric gradient force (gradient end force) This electric gradient force is a force which is received when a dielectric material having no net charge is placed in an uneven electric field, and is always pulled toward the stronger electric field.

In the above, in order for the Coulomb force to work, the droplets need to be charged. As a mechanism for charging the droplet, a mechanism for charging when a raindrop or the like comes into contact with the surface of the dielectric when the raindrop falls can work. In particular, when the surface is treated with a fluorine compound or the like, the droplets are easily charged by contact, which is suitable for this purpose.

As another method, there is a method in which an ionizer that emits positive or negative ions is installed in an external space, or a corona discharger is installed to forcibly charge the external space.

[0016] The electrostatic force can be applied to the droplet by such a method, but since the Coulomb force is generally larger than the gradient force, it is important to be charged in order to use this force. In the case of a large charge, the applied voltage may be small, but in the case of a small charge, a high voltage needs to be applied, which results in an increase in the size of the power supply device.

[0017]

Next, the present invention will be described in detail.
First, specific components will be described. Preferred constituent elements of the present invention are listed below. (1) A plurality of electrodes are arranged inside a dielectric, and an electric field is applied near the surface. (2) The surface of the dielectric is subjected to a water-sliding treatment.

The applied voltage in the present invention is not particularly limited, and may be AC or DC. When a DC voltage is applied, the direction of movement of the droplet is limited to one direction, which is convenient for use in applications such as collection. In addition, when an AC voltage is applied, the lower limit of the voltage at which the water droplet causes flashover increases, so that a higher voltage can be applied.

When the applied voltage is AC, the frequency may be 0.01 Hz or more and 100 Hz or less.
It is more preferable that the frequency is not less than 05 Hz and not more than 80 Hz.
It is more preferable that the frequency is 1 Hz or more and 40 Hz or less. If the frequency of the applied voltage exceeds 100 Hz, the water droplets do not move and vibrate on the spot.

In the present invention, reducing the applied voltage is important for the purpose of preventing dielectric breakdown, saving power, and miniaturizing the voltage device, and the following measures can be taken. It is.

The voltage applied can be reduced by positively charging the water droplets in combination with the ionizer. Examples of such an ionizer include a corona discharge ionizer using a metal electrode, a silicon electrode or a glass-coated electrode, and a light irradiation type ionizer that irradiates inert gas with soft X-rays and irradiates ultraviolet rays with nitrogen gas. No.

When the weight, drop height, and water conductivity of the water droplet can be controlled, the weight of the water droplet is increased, the height at which the water droplet falls, or the conductivity of the water droplet is reduced. It is possible to reduce the applied voltage.

It is also possible to reduce the applied voltage by arranging the electrodes near the surface, changing the electrode shape, the electrode material, the distance between the electrodes, and changing the dielectric constant of the dielectric. These contrivances may be used alone or may be combined.

In the present invention, the water-sliding treatment is performed by coating the surface with a substance having a water-sliding property. Examples of such a substance exhibiting water slip include, for example,
Silane coupling agents, titanate coupling agents,
Examples include an aluminum-based coupling agent, an isocyanate-based coupling agent, and a zirconium-based coupling agent.

Further, for example, pitch fluoride or fluorine resin, specifically, polytetrafluoroethylene, tetraethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether Copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkylvinyl ether copolymer,
Polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, graphite fluoride and the like may be used.

It is known that controlling the surface structure changes the water repellency of the surface, and it is known that a surface having an uneven structure has a higher water repellency than a smooth surface. In addition, it is known that the surface slipperiness also changes depending on the surface structure, and it is possible to control the surface slipperiness by controlling the surface structure.

Examples of such surface processing for controlling the surface structure include machining including cutting, grinding, and electrolytic processing, electric processing including electroplating and laser processing, plasma processing, and electrolysis. , Chemical reaction, microbial reaction, chemical processing including diffusion controlled aggregation, vacuum deposition, lithography, ion beam processing, and the like.

When the above-mentioned surface treatment is applied to a member requiring transparency, it is effective to make the surface uneven, and the width and height of the uneven structure may be in the range of 1 nm to 100 μm. , Preferably in the range of 1 nm to 30 μm, more preferably in the range of 5 nm to 5 μm.
The shape of the uneven structure is not particularly limited, and may not be uniform. One of the suitable uneven structures is a structure in which large unevenness and small unevenness are combined.

In the case where the surface of the functional member of the present invention is subjected to unevenness treatment, it is desired that the width and height of the uneven structure be smaller than the diameter of the water droplet to be removed. If the width and height of the uneven structure are larger than the diameter of the water droplet, the unevenness acts as a resistance to the water droplet, and on the contrary, hinders the slipperiness of the water droplet.

The substrate surface to which the coating composition of the present invention is applied is preferably clean. In particular, when applying the composition to an existing base material such as a vehicle housing or an outer wall of a building, it is preferable to perform cleaning by a known method such as using a cleaning agent in advance.

The substance from which the functional member of the present invention can be removed is not limited to water droplets, but may be a liquid having oil or the like, a solid such as fine particles, or a compound having a chargeability such as a composite thereof. , Can be removed in principle.

The substrate to which the present invention can be applied includes ceramics, glass, plastic,
Wood, stone, cement, concrete, combinations thereof, and laminates thereof can be suitably used. The substrate to which the present invention can be applied can be applied to any substrate which is required to have a drip-proof property on a surface, a water-repellent property, an antifouling property for water-based dirt, a washing property for running water, an anti-icing snow property and the like.

Substrates requiring surface drip-proof properties include:
Vehicle windshields such as vehicle side glass, window glass for railway vehicles, etc., vehicle windshields such as automotive windshields, motorcycle windshields, vehicle mirrors such as vehicle door mirrors, motorcycle rearview mirrors, etc., in front of the vehicle Vehicle lighting covers such as headlight covers, motorcycle headlight covers, instrument panel covers such as motorcycle instrument panel covers, architectural window glasses, road mirrors, outdoor lighting covers, motorcycle helmet shields, camera lenses, A transparent substrate such as a camera lens cover, a mirror substrate (or a film adhered thereon) that loses visibility due to the attachment of raindrops, an insulator (or a film adhered thereon)
And the like, in which the adhesion of water droplets lowers the electrical insulation, such as fins for heat exchangers (or films attached to them), which reduce the efficiency by connecting the water droplets to the ventilation path, etc. Can be suitably used.

The base material required to have a drainable surface is a bathtub, a toilet, a sink, a kitchen sink, a sink, a cooking range, a dishwasher, a dish dryer, a cupboard, a drain basket,
Good drying of the surface, such as bathroom floor material, bathroom wall material, bathroom ceiling material, vehicle exterior and coating (or film to be adhered on), fast drying, propagation of microorganisms by water adhesion Prevention can be expected.

The base material which is required to have a surface which is suitable for washing with running water is a building material, a building exterior, a window frame, a building window glass, a vehicle window glass, a vehicle exterior and coating, a signboard, a traffic sign. , Road noise barriers, railroad noise barriers, guardrail exteriors and coatings, outdoor lighting covers, bridges, insulators, solar cell covers, solar water heater collector covers, greenhouses, vehicle lighting covers, gaze guides, roads Outdoor components that can be cleaned by exposure to rain, such as reflectors, road decorative panels, railing, vehicle mirrors, outdoor surveillance cameras (or films on them); tunnel interiors and coatings, building materials, Building interiors, window frames, window glasses, housing equipment, toilets, bathtubs, washbasins, lighting fixtures, lighting covers, dishwashers, dish dryers, sinks, cooking ranges, kitchen hoods,
A member that can be washed with running water, such as a ventilation fan, a bathroom floor material, a bathroom wall material, a bathroom ceiling material, a kitchen sink (or a film stuck thereon), and the like can be preferably used.

As the base material which is required to have the ability to prevent icing and snow on the surface, roofing materials, antennas, transmission lines, and the like can be suitably used.

In addition, there is also a possibility that the present invention can be used for a substrate such as an inner wall of a vacuum vessel (or a film to be adhered thereon) which requires rapid removal of water adhering to the surface of the substrate.

[0038]

EXAMPLES The present invention will be described more specifically below with reference to examples and comparative examples, but the technical scope of the present invention is not limited to these examples.

(Preparation of Coating Composition for Providing Concavo-convex Structure) Preparation Example 1 Boehmite particles (Condea Chemie, Germany)
ISPAL 18N4, particle size 20-40 nm) 0.07
2 parts, 1.098 parts of tris (2,4-pentanedionato) aluminum (Tokyo Kasei Co., Ltd.) and ethanol 3
0 parts were mixed and stirred at room temperature by ultrasonic waves for 30 minutes to obtain a coating composition (1-A).

Preparation Examples 2 to 4 Coating compositions were prepared in the same manner as in Preparation Example 1 except that the formulation of boehmite particles and tris (2,4-pentanedionato) aluminum was as shown in Table 1. The products (1-B), (1-C) and (1-D) were obtained.

[0041]

[Table 1]

(Preparation of water-repellent coating composition) Preparation Example 5 Heptadecafluorodecyltrimethoxysilane (Toshiba Silicone Co., Ltd., TSL8233) was added to 20 parts of methanol.
To the solution I to which 1 part was added, a solution II of 0.1 part of water and 28 parts of methanol was slowly dropped, and the mixture was stirred at room temperature for 4 hours to obtain a coating composition (2-A).

Preparation Example 6 In the same manner as in Preparation Example 5, except that heptadecafluorodecyltrimethoxysilane was changed to 0.24 part of methyltrimethoxysilane (Shin-Etsu Silicone Co., Ltd., LS-530). A coating composition (2-B) was obtained.

Preparation Example 7 A coating composition was prepared in the same manner as in Preparation Example 5, except that heptadecafluorodecyltrimethoxysilane was replaced with 0.66 parts of octadecyltrimethoxysilane (TSL8185, Toshiba Silicone Co., Ltd.). (2-C) was obtained.

Preparation Example 8 In Preparation Example 5, heptadecafluorodecyltrimethoxysilane was replaced by heptadecafluorodecyltrimethoxysilane.
A coating composition (2-D) was obtained in the same manner as in Preparation Example 5, except that the mixture was changed to a mixture of 5 parts and 0.12 parts of methyltrimethoxysilane.

Preparation Example 9 In Preparation Example 5, heptadecafluorodecyltrimethoxysilane was replaced by heptadecafluorodecyltrimethoxysilane.
A coating composition (2-E) was obtained in the same manner as in Preparation Example 5, except that the mixture was changed to a mixture of 5 parts and 0.33 part of octadecyltrimethoxysilane.

Preparation of (Dielectric with Water-Sliding Surface Treatment) Apparatus Example 1 The coating composition (1-A) prepared in Preparation Example 1 was applied to Pyrex glass cut to 50 × 75 × 1 mm.
The coating was performed by spin coating under the conditions of 00 rpm and 10 seconds. After drying at room temperature for several minutes, it was placed on a hot plate and heated at 500 ° C. for 20 seconds. The cycle of coating, drying and heating was repeated five times to obtain a coated dielectric test plate a '. Coating composition (2-A) prepared in Preparation Example 5
Was placed in an ashtray and dried at room temperature for 2 hours to evaporate the solvent. Place the coating (a ') on an ashtray, place it in a Pyrex (registered trademark) petri dish, and cover with a lid.
The coating composition (2-A) was heated by heating at 50 ° C. for 30 minutes to obtain a coated dielectric test plate (a).

Apparatus Examples 2 to 4 The coating compositions (1-B) prepared in Preparation Examples 2 to 4 instead of the coating composition (1-A) in Apparatus Example 1,
Except that (1-C) and (1-D) were used, in the same manner as in Example 1 of the apparatus, coated dielectric test plates (b ′), (c ′) and (d ′) were obtained. Body test plate (b),
(C) and (d) were obtained.

Apparatus Example 5 2 cc of the coating composition (2-C) prepared in Preparation Example 7 was placed in an ashtray and dried at room temperature for 2 hours to evaporate the solvent. A Pyrex glass cut into a size of 50 × 75 mm) was placed on an ashtray, which was then placed in a Pyrex petri dish, which was then capped, heated at 250 ° C. for 30 minutes, subjected to a steam treatment of the coating composition (2-C), and coated. A dielectric test plate (e) was obtained.

Apparatus Example 6 In Apparatus Example 5, a coating composition (2-C) was prepared.
A coated dielectric test plate (f) was obtained in the same manner as in Apparatus Example 5 except that the coating composition (2-D) prepared in Example 1 was used.

Apparatus Example 7 In Apparatus Example 5, the coating composition c was changed to the coating composition (2-E) prepared in Preparation Example 9 at 250 ° C. 30
Example 5 except that the steam treatment was changed to 150 ° C for 30 minutes.
In the same manner as in the above, a coated dielectric test plate (g) was obtained.

Apparatus Example 8 In Apparatus Example 5, a coating composition (2-C) was prepared.
A coated dielectric test plate (h) was obtained in the same manner as in Apparatus Example 5 except that the coating composition (2-A) prepared in the above was used.

Apparatus Example 9 In Example 7, a coating composition (2-E) was prepared in Example 6.
A coated dielectric test plate (i) was obtained in the same manner as in Apparatus Example 7, except that the coating composition (2-B) prepared in Example 1 was used.

(Production of Dielectric Having Electrodes) Apparatus Example 10 As shown in FIG. 1, a dielectric test plate 1 made of Pyrex glass of 200.times.200.times.1 mm was provided with a 50.times.8
Two aluminum tapes cut to 0 mm were stuck together at an interval of 10 mm so that the sides of 80 mm faced each other to form electrodes 2, and a dielectric test plate I with electrodes was obtained. A lead wire is connected to one of the electrodes of the dielectric test plate I with electrodes,
A high voltage cable was connected to the other electrode.

Apparatus Examples 11 to 14 In Apparatus Example 10, the shapes and intervals of the aluminum tapes are shown in FIGS.
Except that it was as shown in 5, the same as in Apparatus Example 10,
Dielectric test plates II, III, IV and V with electrodes were obtained. A lead wire and a high-voltage cable were connected to the electrodes in the same manner as in Example 10.

Example 1 The dielectric test plate with electrode I prepared in the device example 10 was supported such that the surface to which the electrode was attached was on the lower side, and the coated test plate (a ) Is placed so that the water-repellent surface faces up and straddles the electrodes, and the test plate (a-
I) was obtained.

Examples 2 to 7 In Example 1, the apparatus examples 2 to 4 were used instead of the coating test plate (a).
In the same manner as in Example 1 except that the coated test plates (b), (c), and (d) prepared in
-I), (d-I), (e-I), (f-I), (g-
I) was obtained.

Examples 8 and 9 In Example 1, a device example 1 was used instead of the dielectric test plate I with electrodes.
Test plates (a-I) were prepared in the same manner as in Example 1 except that the dielectric test plates with electrodes II and III prepared in Examples 1 and 12 were used.
I) and (a-III) were obtained.

Embodiments 10 and 11 In Embodiment 1, the device example 1 is replaced with the dielectric test plate I with electrodes.
In the same manner as in Example 1 except that the dielectric test plates with electrodes IV and V prepared in 3 and 14 were used, the test plates (a-IV),
(A-V) was obtained.

Comparative Examples 1 and 2 In Example 1, the device examples 8 and 9 were used instead of the coated test plate (a).
Test plates (h-I) and (i-I) were obtained in the same manner as in Example 1 except that the coated test plates (h) and (i) prepared in the above were used.

(Evaluation) (1) Evaluation of Water Repellency The water repellency of the prepared test pieces a to i was evaluated by the contact angle with water. The contact angle was measured using a CA manufactured by Kyowa Interface Science Co., Ltd.
-X was used.

(2) Evaluation of Water Sliding The water sliding of the prepared test pieces a to i was evaluated by measuring an angle at which a water drop started to slide. Hereinafter, the angle at which the water droplet begins to slide is defined as the “fall angle”. In addition, the falling angle measurement system SA- manufactured by Kyowa Interface Science Co., Ltd.
Type 11 was used.

(3) Evaluation of Water Drop Removal Effect The lead wire was grounded, and the high voltage cable was connected to a high voltage power supply (Model 610D manufactured by Trek Japan). Distilled water was dropped at the center of the electrode with an injection needle, and a voltage was applied.
The voltage when the water droplet began to move was measured. The measurement is 1 /
An output of 1000 was measured with a tester. The weight of the water droplet was also measured.

(4) Evaluation of Frequency Effect The same method as in the evaluation of the water droplet removal effect was used except that a Trek Japan Model FG-2A function generator was connected to a high-voltage power supply so that an AC voltage could be applied. The voltage and frequency at which it began to move were measured. The measurement was made with an oscilloscope at an output of 1/1000. The weight of the water droplet was also measured.

(5) Evaluation of Charge of Water Drop Using the test plate (a-III) used in Example 9, the effect of the charge of water drop was evaluated. The voltage when the water droplet started to move was measured in the same manner as in the evaluation of the water droplet removal effect, except that the falling height of the water droplet and the weight of the water droplet were varied. The measurement was made with a tester at an output of 1/1000. The charge amount and the removal effect were evaluated by changing the contact area between the test plate and the water droplet. Further, the minimum voltage at which the water droplet started to move when a water droplet having a different water droplet weight was dropped after the voltage was first applied to the electrode was evaluated.

(6) Evaluation of Charge of Water Drop Using the test plate (a-III) used in Example 9, the charge of the water drop was evaluated. With an injection needle, distilled water was dropped at the center of the electrode, and a grounded metal needle was brought into contact with the water drop,
A voltage was applied. One voltage was measured when the water droplet started to move. The measurement was made with a tester at an output of 1/1000.

(7) Evaluation of Electrode Shape Test pieces (a-I) and (a-I) used in Examples 1, 8, and 9
Using I) and (a-III), the voltage when the water droplet started to move was measured with the water droplet weight and the falling height kept constant. The measurement was made with a tester at an output of 1/1000.

(8) Evaluation of electrostatic force acting on water droplets Test plates (a-IV), (a-IV) used in Examples 10 and 11
V), the lead wire was grounded, and the high-voltage cable was connected to a high-voltage power supply (Model 610D manufactured by Trek Japan). Distilled water was dropped at the center of the electrode with an injection needle, and a voltage was applied. A digital video camera was used to capture the movement of water droplets. The ratio of the Coulomb force to the gradient force was evaluated by measuring the direction in which the water droplet began to move.

Table 2 shows the evaluation results of (1) and (2).

[0070]

[Table 2]

The evaluation results of (3) are shown in FIGS. FIG.
Shows the relationship between the water-sliding property and the applied voltage when the water-drop weight is 7 mg in an experiment for examining the effect of the water-sliding property on the water-drop removing effect. FIG. 7 shows the relationship between the water-sliding property and the applied voltage when the water-drop weight is 42 mg in an experiment for examining the effect of the water-sliding property on the water-drop removing effect.

FIG. 8 shows the evaluation result of (4). FIG.
The relationship between the water drop weight and the resonance frequency in an experiment for examining the effect of the frequency of the applied voltage on water drop removal is shown.
Note that the resonance frequency is defined here as a frequency at which a water drop vibrates in synchronization with the frequency of the applied voltage.

The evaluation results of (5) are shown in FIGS. FIG. 9 shows the relationship between the drop height of the water droplet and the applied voltage in an experiment for examining the effect of the charge amount of the water droplet on the removal of the water droplet. Dropping a water drop is one means for charging the water drop, and changing the height changes the contact area with the dielectric surface to change the charge amount of the water drop. FIG. 10 shows the relationship between the weight of the water droplet and the applied voltage in an experiment for examining the effect of the charge amount of the water droplet on the removal of the water droplet. Changing the weight of a water droplet is one means of changing both the water slippage and the charge. FIG. 11 shows the relationship between the weight of the water droplet and the applied voltage in an experiment for examining the effect of the charge amount of the water droplet on the removal of the water droplet. The stationary water droplet is a measurement of the applied voltage when a voltage is applied after a water droplet is dropped and stopped, and the falling water droplet is a measurement of the applied voltage when the water droplet is dropped after the voltage is applied. It is.

FIG. 12 shows the evaluation result of (6). FIG.
Shows the relationship between the ground state of the water droplet and the applied voltage in an experiment for examining the effect of the charge amount of the water droplet on the removal of the water droplet. It is shown that grounding a water drop is also one means for increasing the charge amount of the water drop.

FIG. 13 shows the evaluation result of (7). FIG.
Shows the relationship between water droplet weight and applied voltage in an experiment for examining the effect of the electrode shape on water droplet removal. This shows that the electric field strength is different even at the same applied voltage by changing the electrode shape.

FIG. 14 shows the evaluation result of (8). FIG.
Is an experiment for examining the electrostatic force acting on water droplets.
The behavior of a water droplet every 33 seconds is shown. A Coulomb force is acting in a direction parallel to the line of electric force, and a gradient force is acting in a vertical direction. By examining the direction in which the water droplet starts to move, the ratio of the magnitudes of the two forces can be obtained.

FIG. 15 shows an example of a 3D image obtained by observing the dielectric surface of the present invention with an atomic force microscope. FIG. 16 shows an example of the behavior of a water droplet on a dielectric when an AC voltage having a frequency of 3.7 Hz and an effective voltage of 2.0 kV is applied to the dielectric of the present invention. Water droplets on the dielectric are reciprocating between the electrodes in synchronization with the applied voltage frequency.

FIG. 17 is a sketch drawing showing an example of a water droplet removing apparatus in which an ionizer is combined with a dielectric according to the present invention.
Numeral 3 indicates a dielectric material subjected to a concavo-convex treatment and water-repellent treatment, numeral 4 indicates a comb-shaped electrode, and numeral 5 indicates an ionizer.
A voltage controlled via an AC power supply 8, an ion controller 7, and a transformer unit 6 is applied to the ionizer 5 to generate ions, and the ions generated by the blower unit 9 are sent out. A predetermined voltage is applied to the electrode 4 from the AC power supply 8.

FIG. 18 is a sketch showing an example in which the dielectric of the present invention is applied to a bathroom mirror. Reference numeral 10 denotes a mirror having an outermost surface subjected to a concavo-convex treatment and a water-repellent treatment, and a predetermined voltage is applied from an AC power supply 8 to a transparent comb-shaped electrode (ITO) 11 provided on the glass of the mirror 10.

FIG. 19 is a sketch showing an example in which the dielectric of the present invention is applied to a vehicle mirror. A transparent comb-shaped electrode (ITO) 11 is provided on the glass of the mirror 10 on which the outermost surface has been subjected to the unevenness treatment and the water-repellent treatment, and a predetermined voltage is applied via the transformer unit 12.

[0081]

As described above, according to the functional member having the droplet removing function and the droplet removing method of the present invention,
Droplets on the water-repellent surface can be removed using an electric field. In particular, a very useful drip-proof effect can be exerted on a transparent body such as a glass or a mirror.

[Brief description of the drawings]

FIG. 1 is a plan view of a dielectric test plate with electrodes I according to an embodiment of the present invention.

FIG. 2 is a plan view of a dielectric test plate with electrodes II according to another embodiment of the present invention.

FIG. 3 is a plan view of a dielectric test plate with electrodes III according to still another embodiment of the present invention.

FIG. 4 is a plan view of a dielectric test plate IV with electrodes according to still another embodiment of the present invention.

FIG. 5 is a plan view of a dielectric test plate with electrodes V according to still another embodiment of the present invention.

FIG. 6 is a diagram showing the water sliding property-applied voltage in the case of a water droplet weight of 7 mg in an experiment for examining the effect of the water sliding property on the water droplet removing effect.

FIG. 7 is a diagram showing the water sliding property-applied voltage when the water drop weight is 42 mg in an experiment for examining the effect of water sliding property on the water drop removing effect.

FIG. 8 is a diagram showing water droplet weight-resonance frequency in an experiment for examining the effect of the frequency of an applied voltage on water droplet removal.

FIG. 9 is a diagram showing a water drop falling height-applied voltage in an experiment for examining the effect of the charge amount of the water droplet on water droplet removal.

FIG. 10 is a diagram showing water droplet weight versus applied voltage in an experiment for examining the effect of the amount of charge of the water droplet on the removal of the water droplet.

FIG. 11 is a diagram showing the relationship between the water droplet weight and the applied voltage in an experiment for examining the effect of the charge amount of the water droplet on water droplet removal.

FIG. 12 is a diagram showing a ground state of a water droplet and an applied voltage in an experiment for examining an effect of a charge amount of the water droplet on water droplet removal.

FIG. 13 is a diagram showing water droplet weight versus applied voltage in an experiment for examining the effect of the electrode type on water droplet removal.

FIG. 14 shows an experiment for examining electrostatic force acting on water droplets.
It is a figure which shows the behavior of the water droplet for every 0.033 second.

FIG. 15 is a diagram showing an example of a 3D image image of the dielectric surface of the present invention observed with an atomic force microscope.

FIG. 16 is a diagram showing an example of the behavior of a water droplet on a dielectric when an AC voltage having a frequency of 3.7 Hz and an effective voltage of 2.0 kV is applied to the dielectric of the present invention.

FIG. 17 is a sketch drawing showing an example of a water droplet removing device in which an ionizer is combined with a dielectric according to the present invention.

FIG. 18 is a sketch drawing showing an example in which the dielectric material of the present invention is applied to a bathroom mirror.

FIG. 19 is a sketch drawing showing an example in which the dielectric of the present invention is applied to a vehicle mirror.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Dielectric test plate (pyrex glass) 2 Electrode 3 Dielectric subjected to unevenness treatment and water repellent treatment 4 Comb-shaped electrode 5 Ionizer 6 Transformer 7 Ion controller 8 AC power supply 9 Blower unit 10 Surface unevenness treatment and water repellent treatment 11 Transparent comb electrode (ITO) on glass 12 Transformer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhito Hashimoto 2207-2, Iijima-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture No. 213 New Building Hongodai D Bldg. −10− 303 F term (reference) 3B111 AA01 4G059 AA01 AB01 AB09 AB11 AB13 AC22 EA01 EA18 EB05 FA05 FA22 FB01 GA01 GA04 GA16 4H020 BA36

Claims (8)

[Claims] 1. A dielectric in which a plurality of electrodes are arranged so that an electric field is applied near a surface thereof, wherein the dielectric surface is subjected to a water-sliding treatment, and a voltage is applied to the electrodes. A functional member having a function of removing droplets on the surface thereof. 2. The functional member according to claim 1, wherein a falling angle on the surface of the dielectric material subjected to the water-sliding treatment is 30 ° or less. 3. The functional member according to claim 1, wherein the water-slidable dielectric is transparent. 4. A method for removing a droplet, comprising applying an electric field to the dielectric surface subjected to the water-sliding treatment to remove the droplet on the surface. 5. A method for removing a droplet, comprising applying a voltage to the functional member according to claim 1 to remove a droplet on the surface thereof. 6. The frequency of an applied voltage is 0.01 Hz or more and 1
6. The method for removing a droplet according to claim 4, wherein the frequency is not higher than 00 Hz. 7. A method for drip-proofing glass by the method according to claim 4. Description: 8. A drip-proof method for a mirror according to any one of claims 4 to 6.