JP4877770B2 - Method for forming a highly water-repellent surface - Google Patents

Description

The present invention relates to a method for forming a highly water-repellent surface on a substrate by coating and drying a particulate metal oxide dispersion type compound using a spin coating method.
More specifically, by forming a coating film obtained by diluting a dry oil in which fine metal oxide is dispersed and supported on the surface of the material with a volatile solvent by a spin coating method, it is mechanically stable after drying and has a high water repellency. The present invention relates to a method for forming a surface.

  In recent years, many technologies for forming a highly water-repellent surface on the material surface have been announced. Many of these technologies, however, have a surface with a highly water-repellent surface formed by forming an uneven structure on the material surface, such as the surface of a lotus leaf. This is a technique for forming a film, or a technique for forming a highly water-repellent film on a material surface using a fluorine-based compound. As the former, for example, in Patent Document 1, when laser ablation is performed by irradiating the surface of a mixture in which a polymer component and water-repellent fine particles are uniformly dispersed and mixed, the surface irradiated with the laser and its surface It is described that the surface can exhibit excellent water repellency by removing the polymer component in the vicinity (this phenomenon is referred to as sputtering) and exposing the irregular surface due to the water-repellent fine particles to the surface. Further, Patent Document 2 is based on a mixture obtained by adding and mixing a foaming agent and / or an aggregating agent to a water-soluble organic liquid containing a TFE resin having an average particle size of 0.1 to 0.5 μm and a polyamic acid. A technique is described in which after coating on a material, this is heated to remove water, water-soluble organic liquid, foaming agent and / or flocculant, and polyamic acid is condensed to form polyimide or polyamideimide. Yes.

  Next, as an example of the latter, Patent Document 3 includes a water-repellent binder resin, polytetrafluoroethylene particles and a dispersant, and, if necessary, a low heat capacity particle and a solvent. A technique is described for a surface treatment formulation that provides a film and that provides a highly water-repellent and easy-to-drop paint film that can prevent icing and snowing. Both technologies have their merits and demerits, and the fusion of both is progressing.

JP 2005-179441 A Japanese Patent Laid-Open No. 10-17695 International Publication WO2003-93388

  In the case of a method of forming a concavo-convex structure on the material surface to form a highly water-repellent surface, it is not easy to form a concavo-convex structure stably and inexpensively on the coating film surface applied to the substrate film surface, There is a problem that it takes time to go through complicated manufacturing processes and the formation cost is high, and there is a need for a technology to form a fine concavo-convex structure exhibiting high water repellency on the material surface at a lower cost and with a simpler manufacturing process. It was.

  As a result of diligent research in view of these problems, the inventors of the present invention drop a solution of a specific composition on an object or substrate on which a concavo-convex structure is formed to obtain a highly water-repellent surface, or in the specific composition solution. After immersing the object or substrate, the object or substrate is mechanically rotated in the air to form a fine uneven structure on the object or substrate surface, and the object or substrate surface can be easily raised. A method for converting to a water-repellent surface was found.

  The invention described in the present application is composed of the following first to seventh inventions (hereinafter referred to as “the present invention” unless otherwise specified).

  That is, the first invention of the present application is a combination of a water-repellent surface-treated fine particle metal oxide having a primary particle size in the range of 10 nm to 50 nm, a drying oil and a volatile solvent, and excluding the volatile solvent. Applying a fine particle metal oxide dispersion type compound in which the blending amount of the water-repellent surface-treated fine particle metal oxide is 60 to 80% by mass with respect to the amount of the substance on the substrate surface using a spin coating method. And a method for forming a highly water-repellent surface.

  A second invention of the present application is the method for forming a highly water-repellent surface according to the first invention, wherein the spin coating method uses a spin coater.

  According to a third aspect of the present invention, the spin coater has a rotational speed in the range of 2000 to 6000 revolutions per minute in the spin coating method. The formation of the highly water-repellent surface according to the first or second aspect of the invention Is in the way.

  In the fourth invention of the present application, the fine particle metal oxide in the fine particle metal oxide dispersion type compound is titanium oxide, zinc oxide, silicon dioxide, aluminum oxide, zirconium oxide, cerium oxide, lead oxide, tin oxide, iron oxide, The method for forming a highly water-repellent surface according to any one of the first to third inventions, which is at least one of manganese oxide, cobalt oxide, and chromium oxide.

  The fifth invention of the present application is characterized in that the drying oil used in the fine particle metal oxide dispersion type compound is at least one of linseed oil, poppy oil, walnut oil, safflower oil and sunflower oil. The method for forming a highly water-repellent surface described in the third invention.

  According to a sixth aspect of the present invention, the water-repellent surface treatment of the particulate metal oxide is a monoalkyltrialkoxysilane having an alkyl group with an alkyl chain length in the range of 6 to 12, trimethylsilane, methylhydrogenpolysiloxane , Silicone resin, one-end reactive dimethylpolysiloxane, metal soap, organic titanate, organicated aluminate, fluorinated silane, one-end reactive perfluoropolyether, and silane coupling agent. The method for forming a highly water-repellent surface according to any one of the first to third inventions is characterized in that.

  In the seventh invention of the present application, the volatile solvent in the water-repellent metal oxide dispersion type compound is a lower alcohol, n-hexane, cyclohexane, toluene, xylene, isoparaffin, fluorocarbon, next-generation flon, n-butane, The method for forming a highly water-repellent surface according to any one of the first to third inventions, which is at least one of cyclic siloxane and volatile silicone.

  From the above, the present invention contains a water-repellent surface-treated fine particle metal oxide having a primary particle diameter in the range of 10 nm to 50 nm, a drying oil, and a volatile solvent, and the amount of the compounded material excluding the volatile solvent Is applied to the substrate surface by a spin coating method such as a spin coater. By processing, it has become possible to easily and inexpensively form a highly water-repellent surface on the substrate surface.

Hereinafter, the first to seventh inventions of the present application (hereinafter collectively referred to as “the present invention”) will be described in detail.
First, the present invention blends a water-repellent surface-treated fine particle metal oxide having a primary particle size in the range of 10 nm to 50 nm, a drying oil and a volatile solvent, and with respect to the amount of the blended substance excluding the volatile solvent. By applying a fine particle metal oxide dispersion type compound having a water repellent surface treatment fine particle metal oxide in the range of 60 to 80% by mass to the substrate surface using a spin coating method, In addition, the present invention relates to a method for forming a highly water-repellent surface, characterized in that a highly water-repellent surface is formed on a substrate surface at low cost.
The “rotary coating method” referred to in the present invention is a coating method represented by a spin coater, in which an object or a substrate is fixed to a rotating shaft, and a solution of a fine particle metal oxide dispersion type compound is dropped onto the object. Alternatively, after the object is immersed in a solution of the fine particle metal oxide dispersion type composition, it is rotated at a high speed to remove excess solution itself, and the solution is applied to the surface of the object relatively uniformly. Spin coaters are usually used for coating two-piece cans and very low-viscosity solutions such as liquid crystals and resists. In some cases, a fine uneven structure can be formed on the substrate surface. By utilizing this phenomenon, a highly water-repellent surface can be formed very easily on the substrate surface. In the present invention, when the rotation speed of the object or substrate to be coated is in the range of 2000 to 6000 rotations per minute, the uneven structure is stably and clearly formed on the coating film applied to the surface of the object or substrate. Can be made.

  In the present invention, a water-repellent surface-treated fine particle metal oxide having a primary particle diameter in the range of 10 nm to 50 nm is used. As a method for evaluating the primary particle diameter of this fine particle metal oxide, an electron microscope observation was performed. . If the primary particle size of the fine particle metal oxide is out of this range, it becomes difficult to stably form a fine uneven structure on the coating film applied to the substrate surface, and improvement in the high water repellency of the substrate surface cannot be expected. Cases arise.

  In the present invention, the water-repellent surface treatment of the particulate metal oxide means monoalkyltrialkoxysilanes such as octyltriethoxysilane having an alkyl group having an alkyl chain length in the range of 6 to 12 carbon atoms, trimethylsilane, methyl Hydrogen polysiloxane, silicone resin, one-end reactive dimethylpolysiloxane, metal soap such as zinc stearate, organotitanate, organoaluminate, fluorinated silane, one-end reactive perfluoropolyether, silane coupling Surface treatment with an agent or the like. The surface treatment amount of these fine particle metal oxides is in the range of 0.5 to 20% by mass, more preferably in the range of 3 to 15% by mass with respect to the mass of the metal oxide before the surface treatment. . In addition, the surface treatment of these metal oxides may be performed by combining a plurality of surface treatment agents even if they are treated with a single surface treatment agent.

  Among these surface treatment agents, octyltriethoxysilane and octyltrimethoxysilane are particularly preferred surface treatment agents having excellent dispersion stability of the particulate metal oxide. Furthermore, as a method for surface treatment of the fine particle metal oxide, a dry method and a wet method are generally exemplified. However, wet methods such as a bead mill which has a high effect of releasing the aggregation of the fine particle metal oxide and improving dispersibility in dry oil. A surface treatment method using a fine pulverizer is preferable.

  As the fine particle metal oxide used in the present invention, a metal oxide having a primary particle diameter in the range of 10 nm to 50 nm can be used, and the shape thereof is spherical, substantially spherical, rod-shaped, spindle-shaped, plate-shaped, indefinite. Any shape such as a shape may be used. When the primary particle size is less than 10 nm or 50 nm or more, it is difficult to form a highly water-repellent surface on the substrate, which is an effect of the present invention, and there is a problem that the water resistance of the highly water-repellent surface is lowered.

  As the particulate metal oxide in the present invention, specifically, at least one of titanium oxide, zinc oxide, silicon dioxide, aluminum oxide, zirconium oxide, iron oxide, cerium oxide, tungsten oxide, cobalt oxide, manganese oxide, and tin oxide is used. It is preferable to include, and it is preferable to include at least one of titanium oxide, zinc oxide, and silicon dioxide. These metal oxides are safe and have excellent stability during film formation. In addition, these metal oxides used in the present invention often exhibit solid catalyst activity in the form of fine particles, and cause oxidative degradation of the drying oil in the formulation over time. When the catalyst is coated with the catalyst, the catalytic activity is significantly lowered, and this has a favorable effect on the long-term stability of the coating film, which is preferable.

  In the fine particle metal oxide dispersion type compound used in the present invention, the compounded mass of the fine particle metal oxide subjected to the water-repellent surface treatment with respect to the amount of the compounded material excluding the volatile solvent is in the range of 60 to 80% by mass. Preferably, if the blending mass is less than 60% by mass, there is a problem that the contact angle of the coating surface with respect to water does not change regardless of whether or not the spin coating method is used. There is a problem that the durability of the coating film is lowered due to insufficient amount of the drying oil to be formed.

The dry oil in the fine particle metal oxide dispersion type compound of the present invention is characterized by using at least one of linseed oil, poppy oil, walnut oil, safflower oil, and sunflower oil, and is fat and oil that hardens by oxygen crosslinking In particular, linseed oil is easy to handle and suitable for use.
The amount of the drying oil is preferably in the range of 10 to 40% by mass, more preferably in the range of 20 to 40% by mass with respect to the amount of the compounding material excluding the volatile solvent. Within this range, there is a merit that the particulate metal oxide is dispersed and fixed in the coating film obtained by curing the drying oil, and the durability of the film is improved.

  Furthermore, the volatile solvent used in the present invention may be an organic solvent that is excellent in the solubility of drying oil and the dispersibility of the particulate metal oxide, and examples thereof include ethyl alcohol, isopropyl alcohol, and propyl alcohol. And volatile silicones such as n-hexane, cyclohexane, toluene, xylene, isoparaffin, fluorocarbon, next-generation fluorocarbon, n-butane, cyclic siloxane, and methyltrimethicone. Of these, decamethylcyclopentanesiloxane, which is a kind of cyclic siloxane, and lower alcohols are particularly preferable because they are excellent in price, availability, and safety to the human body. The blending amount of these volatile solvents in the fine particle metal oxide dispersed blend is preferably in the range of 400 to 1900 parts by weight with respect to 100 parts by weight of the blended substance excluding the volatile solvent. If it is less than 400 parts by mass, the solution viscosity of the fine particle metal oxide dispersion type compound becomes too high, and it is difficult to uniformly adjust the film formation, which causes a problem in coating. Moreover, when it exceeds 1900 mass parts, the coating film after a volatile solvent evaporates will become thin too much, and the problem that coating film strength is insufficient will arise.

  As the fine particle metal oxide dispersion type compound used in the present invention, the above-mentioned components are uniformly mixed and dispersed. At this time, the particulate metal oxide may be either finely pulverized before or in the form of a slurry highly dispersed in a solution. Alternatively, the particulate metal oxide may be added as it is, and then the blend may be finely pulverized using a bead mill or the like to obtain a uniform particulate metal oxide dispersed blend.

  In the present invention, a dispersion in which water-repellent fine particle metal oxide is dispersed is applied on a substrate. As a method of dispersing the water-repellent fine particle metal oxide, the surface of the fine particle metal oxide is treated with a surface treatment agent. It is preferable to use a combination of methods using a mechanical dispersion force, such as a method using a surface treatment to improve dispersion stability and a method using a surfactant to increase the stability of the fine particle metal oxide.

  The surfactant used herein is preferably a silicone-based surfactant having a characteristic that it can be converted to silica after firing. For example, polyether-modified organopolysiloxane, alkyl-polyether-modified organopolysiloxane, polyglyceryl-modified organopolysiloxane It is preferable to use a modified organopolysiloxane selected from at least one of alkyl-modified organopolysiloxanes. Further, as a mechanical dispersion method, a dispersion method using a disper, attritor, homomixer, or the like, a method of spraying a slurry at high pressure, a medium type pulverizer such as a paint shaker, a sand mill, or a pebble mill, or a roll mill is used. The method etc. are mentioned. The former has the merit of being inexpensive and easy to work, and the latter can be highly dispersed, and is a preferable method when importance is attached to the transparency and appearance of the coating film.

  As a coating method of the water-repellent fine powder metal oxide dispersion type compound used in the present invention, a method of coating with a uniform thickness using an applicator, a roll coater or the like, a method of coating using a brush, etc. There is a method of immersing the substrate in the substrate, but there are problems that the coating strength becomes uneven or the strength becomes weak when applied thickly. In the present invention, the coating is applied to the surface of the substrate using a spin coating method.

The spin coating method will be described in more detail. If the substrate is a plate-like material, the fine particle metal oxide dispersion-type compound is hung at the center using a spin coater, and then the substrate itself is rotated at a high speed to remove the excess. Examples include a method for crosslinking a dry oil film such as removing the dispersion compound and further drying by heating.
In addition, when the substrate is a three-dimensional object, the rotation shaft is fixed in the vicinity of the center of gravity of the three-dimensional object, and after the three-dimensional object is immersed in the fine particle metal oxide dispersion type compound as it is, the rotation shaft is rotated at a high speed, Further, a crosslinking method such as heat drying may be mentioned.
Furthermore, there is no limitation on the material and the material of the substrate, and the coating can be performed except for a material that cannot be applied because the fine particle metal oxide dispersion compound is repelled. In the case of such a substrate that cannot be coated, a method may be applied in which a primer that can be coated in advance is applied to the substrate and the surface is coated. Further, as a method of further emphasizing the uneven structure of the coating film, a method of washing the coated substrate with running water is also effective.

  In the fine particle metal oxide dispersion type compound used in the present invention, components such as fillers, oil agents, preservatives, fungicides, bactericides, ultraviolet absorbers, colorants and the like may be used as appropriate in addition to the above components. it can.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
In addition, the evaluation method with respect to the various characteristics used by the Example and the comparative example is shown below.
<Evaluation method of contact angle>
Water droplets were brought into contact with the substrate using a contact angle measuring device (DM500 type contact angle measuring device manufactured by Kyowa Interface Science Co., Ltd.), and the contact angle was determined from data immediately after the substrate. The analysis software FAMAS manufactured by the company was used for the analysis of the contact angle.
Moreover, the sample used for the measurement was dried again and the measurement of the contact angle was repeated, and it was confirmed whether or not the high water repellency was maintained by repeated contact with water.

First, octylsilylated fine particle titanium oxide (octyltriethoxysilane 10% by mass treated silica / alumina treated fine particle titanium oxide. Average particle diameter 35 nm. Toluene was used as a solvent and reacted in a bead mill, followed by drying and heat treatment. 40 parts by mass and 60 parts by mass of decamethylcyclopentasiloxane (a kind of cyclic volatile silicon, boiling point 210 ° C.) were roughly mixed, and then finely pulverized using a bead mill (horizontal sand grind mill), and octyl A slurry of octylsilylated fine particle titanium oxide in which silylated fine particle titanium oxide was uniformly dispersed was obtained.
Next, linseed oil is added at a ratio of 40 parts by mass with respect to 60 parts by mass of octylsilylated fine particle titanium oxide in the octylsilylated fine particle titanium oxide slurry, and volatile decamethylcyclopentasiloxane is further added to the total amount. Was prepared to be 5 times the total amount of octylsilylated fine particle titanium oxide and linseed oil.
Using a spin coater (Photoresist Spinner K-359SD-1 type, manufactured by Kyowa Riken Co., Ltd.), 0.2 mL of the above composition was dropped on the center of the glass plate, and then rotated for 5 seconds at a rotation speed of 500 rpm. The coating was completed by rotating for 20 seconds at a rotational speed of 4000 rpm. Thereafter, it was sufficiently dried at 60 ° C. to obtain a stable coating film.

  In the same process as above, the mass ratio of the octylsilylated fine particle titanium oxide and linseed oil was 2: 8 (20 mass%: 80 mass%, hereinafter the same mass% is omitted), 4: 6, 6: 4, 6 .25: 3.75, 6.5: 3.5, 6.75: 3.25, 7: 3, 7.25: 2.75, 7.5: 2.5, 7.75: 2.25 , 8: 2 ratio of each sample could be prepared.

(Comparative Example 1)
The sample of Example 1 was applied at a speed of 0.02 m / sec using an applicator having a 1 mm inch slit on a glass plate without using a spin coater, and then the same as in Example 1. And dried at 60 ° C. to obtain a sample.

Using a sample in which the mass ratio of the octylsilylated fine particle titanium oxide and linseed oil of Example 1 was set to 7.75: 2.25, volatile decamethylcyclopentasiloxane was added in the same manner, and the total amount was octylsilylated. The total mass of fine particle titanium oxide and linseed oil was adjusted to be 5 times the total mass.
A sample was obtained in the same manner as in Example 1 except that the rotation speed of the spin coater was changed to 6000 rpm.
As a result of measuring the contact angle with respect to the purified water of this sample, a high contact angle value of 149 degrees was shown.

  Samples were prepared in the same manner as in Example 2 except that the rotation speed of the spin coater in Example 2 was changed to 2000 rpm. The contact angle of this sample with purified water was 130 degrees, which was slightly lower than that of the sample in Example 2, and the water repellency of the substrate surface was slightly lower.

(Comparative Example 2)
A sample was obtained in the same manner as in Example 1 except that instead of octylsilylated fine particle titanium oxide in Example 1, silica having a primary particle diameter of 5 nm was subjected to octylsilylation treatment in the same manner. The contact angle of the surface of the coating film with purified water was about 120 degrees at the maximum, and it could not be said that a highly water-repellent surface was formed.

(Comparative Example 3)
A sample was obtained in the same manner as in Example 1 except that instead of octylsilylated fine particle titanium oxide in Example 1, silica having a primary particle size of 250 nm was octylsilylated by the same method. The contact angle of the coating surface with purified water was about 115 degrees at the maximum, and a highly water-repellent surface could not be formed.

  As an example of a three-dimensional base material, a metal shaft is fixed to the center of a square block, which is immersed in the fine particle titanium oxide slurry used in Example 2, and rotated at 3000 rpm with a motor. And rotated for 30 seconds. Then, it dried at 60 degreeC and the process was completed. The contact angle of the block with purified water was around 135 ° and had a highly water-repellent surface.

(Summary of results)
FIG. 1 shows the results of measuring the contact angles of the samples in Example 1 and Comparative Example 1 with respect to purified water.
In FIG. 1, the vertical axis represents the contact angle (CA (°)), and the horizontal axis represents the mass ratio of the octylsilylated fine particle titanium oxide to the total mass of the octylsilylated fine particle titanium oxide and linseed oil.
From the results shown in FIG. 1, octyl is better when applied with a spin coater (described as “spin coater”) than when applied with an applicator (described as “applicator”). It was confirmed that the contact angle was significantly increased in the high concentration region of silylated titanium oxide, particularly 60 mass% to 80 mass%. In particular, it has been found that when the concentration ratio of octylsilylated titanium oxide exceeds 70% by mass, the contact angle dramatically increases.

Furthermore, the state of the coating film surface when the mass ratio of octylsilylated titanium oxide and linseed oil was 7.75: 2.25 (77.5 mass%: 22.5 mass%) was observed using a scanning electron microscope. The results are shown in FIG.
FIG. 2 shows that a fine streak structure is formed on the surface of the coating film.

Next, in view of the results of Example 1 (FIG. 1), the mass ratio of octylsilylated titanium oxide and linseed oil in a spin coater that provides a larger contact angle than that of the applicator is 7.5: 2.5 (75 (Mass%: 25% by mass) The influence of the dilution rate with the organic solvent and the rotation angle of the spin coater on the contact angle was examined.
As shown in Table 1, dilution rate, spin coater rotation speed (number of rotations / minute)
The contact angle with respect to the purified water of the coating film surface when each was changed was determined.
The dilution factor on the vertical axis was determined by the same method as in Example 1.
According to Table 1, the contact angle of the coating film surface with purified water is related to the dilution rate of the organic solvent and the rotation speed of the spin coater, and the water repellency of the coating film surface is closely related to these coating film forming conditions. It turns out that it is related.

“Smooth” in the table is applied at a rate of 0.02 m / sec using an applicator having a 1 mm inch slit on a glass plate and then dried at 60 ° C. in the same manner as in Example 1. The contact angle of the obtained one is shown. The unit of viscosity is 10 ⁻³ Pa · s.

From the results of the above examples and comparative examples, the water-repellent fine particle metal oxide dispersion-type compound using the spin coating method has a surface having a significantly higher contact angle compared with the conventional coating method, that is, a high water-repellent surface. It became clear that can be formed. Furthermore, when the surface was observed, it became clear that many streaky microstructures were formed.
Applications of the present invention include the formation of water-free window glass, dirt-resistant tiles, outer wall materials, and the like.

The contact angle measurement result of Example 1 and Comparative Example 1 is shown. In Example 1, the photograph which observed the state of the coating-film surface using the scanning electron microscope in the mass ratio of octyl silylated titanium oxide and linseed oil is 7.75: 2.25 is shown.

Claims (7)

In a method of forming a highly water-repellent surface on a substrate surface using a fine particle metal oxide dispersion type compound comprising fine particle metal oxide, drying oil and volatile solvent, the fine particle metal oxide has a primary particle size of 10 nm to 50 nm. The water-repellent surface-treated fine particle metal oxide is used in the range of 5 to 80% by mass, and the blended mass of the water-repellent surface-treated fine particle metal oxide is 60 to 80% by mass with respect to the amount of the compounded material excluding the volatile solvent. A method for forming a highly water-repellent surface, characterized in that a fine particle metal oxide dispersion type compound is applied to a substrate surface using a spin coating method.   2. The method for forming a highly water-repellent surface according to claim 1, wherein the spin coating method uses a spin coater.   The method for forming a highly water-repellent surface according to claim 1 or 2, wherein the spin coater has a rotational speed in the range of 2000 to 6000 revolutions per minute in the spin coating method.   The fine metal oxide in the fine metal oxide dispersion compound is titanium oxide, zinc oxide, silicon dioxide, aluminum oxide, zirconium oxide, cerium oxide, lead oxide, tin oxide, iron oxide, manganese oxide, cobalt oxide, chromium oxide. The method for forming a highly water-repellent surface according to claim 1, wherein at least one of the above is used.   2. The highly water-repellent surface according to claim 1, wherein the drying oil used in the fine particle metal oxide dispersion type compound is at least one of linseed oil, poppy oil, walnut oil, safflower oil and sunflower oil. Forming method. Water-repellent surface-treated fine-particle metal oxide water-repellent surface treatment for obtaining a fine-particle metal oxide, monoalkyltrialkoxysilanes having an alkyl group with an alkyl chain length in the range of 6 to 12, trimethylsilane, At least one of methyl hydrogen polysiloxane, silicone resin, one-end reactive dimethylpolysiloxane, metal soap, organic titanate, organicated aluminate, fluorinated silane, one-end reactive perfluoropolyether, silane coupling agent The method for forming a highly water-repellent surface according to claim 1, wherein   The volatile solvent in the water-repellent metal oxide dispersion type compound is at least a lower alcohol, n-hexane, cyclohexane, toluene, xylene, isoparaffin, fluorocarbon, next-generation fluorocarbon, n-butane, cyclic siloxane, and volatile silicone. The method for forming a highly water-repellent surface according to claim 1, which is one kind.