WO2010073623A1

WO2010073623A1 - Process for formation of coating film, and coating fluid

Info

Publication number: WO2010073623A1
Application number: PCT/JP2009/007124
Authority: WO
Inventors: 真子義邦; 長谷川博
Original assignee: 株式会社カーメイト
Priority date: 2008-12-26
Filing date: 2009-12-22
Publication date: 2010-07-01
Also published as: JP2010155727A; JP4790003B2

Abstract

Provided is a process for the formation of a coating film, by which a transparent and super water-repellent coating film can be formed without troublesome working. The process comprises: using a coating fluid prepared by dispersing fine particles, the surfaces of which are hydrophobic and which have a mean primary particle diameter of 100nm or smaller, in an organic solvent which contains a hydrophobic solvent in an amount of 65mass% or larger relative to the organic solvent; applying the coating fluid to a substrate, the surface of which is hydrophobic; and thus forming a coating film. The application of the coating fluid may be conducted by an aerosol method, a flow coating method, a method using a hydrophobic and fluid-impregnable article, or other methods.

Description

Coating film forming method and coating liquid

The present invention relates to a coating film forming method and a coating liquid used for forming the coating film, and in particular, exterior walls and roofs of buildings, bodies of aircraft, ships, vehicles, etc., glass, wheels, etc., side mirrors for passenger cars, The present invention relates to a coating film forming method and a coating liquid applied to a heat exchanger, a parabolic antenna, an electric wire, and the like of an air conditioner.

Glass and mirrors installed outdoors or used outdoors, such as passenger car side mirrors and glass, and window glass of houses, are difficult to visually identify when raindrops adhere to them, reducing visibility. To do. Moreover, if raindrops adhere to the outer wall, roof, etc. of the building, the aesthetics are impaired. Furthermore, various problems occur when dew condensation or icing occurs on parabolic antennas, electric wires, etc., or when water droplets adhere to the heat exchanger of an air conditioner. Therefore, the development of a technique for imparting water repellency to the surface of a building such as an outer wall of a building, a parabolic antenna, an electric wire, glass, a mirror, a heat exchanger or the like has been performed. *

For example, JP 2003-206477 A and JP 2003-306670 A disclose a surface of a mirror or the like using a water repellent composition in which inorganic or organic fine particles hydrophobized are contained in an organic solvent. Discloses a method of forming a super water-repellent coating. However, in these methods, the presence of moisture on the surface of an object (mirror or the like) on which a film is formed has an adverse effect, and super water repellency cannot be realized in the formed film. Therefore, it is necessary to sufficiently remove moisture from the surface of the object and dry it before the film forming operation, and a complicated operation is required. In addition, there is a problem that the film forming operation cannot be performed in an environment such as rain. *

JP 2003-206477 A JP 2003-306670 A

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a film forming method and a coating liquid capable of forming a transparent and super-water-repellent coating film without requiring a complicated operation. Is to provide.

In view of the above problems, the present inventors have intensively studied, and as a result, completed the present invention. That is, the coating film forming method of the present invention comprises a coating liquid in which fine particles having a hydrophobic surface and an average primary particle diameter of 100 nm or less are dispersed in an organic solvent containing a hydrophobic solvent in an amount of 65% by mass or more in the total organic solvent. The coating liquid is applied to an object having a hydrophobic surface to form a film. *

In the present invention, the object having a hydrophobic surface can be made hydrophobic by subjecting the surface of the hydrophilic object to a hydrophobic treatment. *

Moreover, as a method of applying the coating liquid to the object, it is preferable to use an aerosol method or a flow coating method, or to coat using a hydrophobic impregnated body. *

In the present invention, the fine particles having a hydrophobic surface are preferably hydrophobic silica. *

The coating liquid of the present invention is characterized in that fine particles having a hydrophobic surface and an average primary particle size of 100 nm or less are dispersed in an organic solvent containing a hydrophobic solvent in an amount of 65% by mass or more in the total organic solvent. . *

Here, the fine particles having a hydrophobic surface are preferably hydrophobic silica.

According to the present invention, a superhydrophobic film having transparency can be formed without performing a complicated operation.

The coating liquid of the present invention is obtained by dispersing fine particles having a hydrophobic surface and an average primary particle diameter of 100 nm or less in an organic solvent. However, this organic solvent needs to contain a hydrophobic solvent in an amount of 65% by mass or more in the total organic solvent, and preferably contains 75% by mass or more. The effect of the present application cannot be exerted with an organic solvent having a hydrophobic solvent content of less than 65% by mass in the total organic solvent. Therefore, if water is present on the surface of the coating object, super water repellency is achieved. It cannot be expressed. *

The fine particles used in the present invention are required to have a hydrophobic surface and an average primary particle size of 100 nm or less. The average primary particle diameter of the fine particles is preferably in the range of 1 to 100 nm, and more preferably in the range of 5 to 100 nm. This is because if the particle diameter of the fine particles exceeds 100 nm, light scattering occurs on the surface of the coating film, and transparency may not be maintained. That is, the coating film in which the fine particles are attached to the surface of glass or the like has irregularities having the same size and height as the fine particles. Therefore, if fine particles having an average particle size of 100 nm or less are attached, the wavelength of visible light ( Mainly about 400 to 800 nm), the surface of the coating film is not scattered and light can be kept transparent. Therefore, when the object to which the coating composition of the present invention is applied is glass, a mirror, etc., the transparency is effectively utilized and it is particularly effective. *

The shape of the fine particles is not limited to a spherical shape in a strict sense. For example, the crystal form or aggregated form may be substantially spherical, cylindrical, scaly, fibrous, indefinite, polyhedral, or the like. *

Fine particles whose surface is hydrophobic are mainly composed of oxides such as silicon, titanium, aluminum, zirconium, antimony, tin, tungsten, zinc, iron, cerium, manganese, copper, magnesium, holmium, nickel, or carbon. However, silicon oxide is particularly preferable. In this invention, these can be used individually or in mixture of 2 or more types. When the fine particles are formed using zinc oxide, antibacterial and antifungal effects can be further imparted to the coating film surface. *

In the present invention, the fine particles having a hydrophobic surface are preferably hydrophobic silica. Here, the term “silica” means not only those that exist strictly in the state of SiO ₂ but also silicon oxide. The fine particles whose surface is hydrophobic means those whose surface is hydrophobized. For example, the hydrophobic silica means one whose surface is hydrophobized.

The method for hydrophobizing the surface of the fine particles is not particularly limited as long as it can impart hydrophobicity to the surface of the fine particles, and is appropriately adopted. For example, it is preferable that the surface contains fluorine or an alkyl group. Examples of the method for containing fluorine or an alkyl group on the surface of the fine particles include a method using an organometallic compound such as a silylating agent, a silane coupling agent, and alkylaluminum. Here, the silylating agent is a compound in which an alkyl group, an allyl group, a fluoroalkyl group containing fluorine, or the like is bonded to a hydrolyzable silyl group having affinity or reactivity with an inorganic material. Examples of the hydrolyzable group bonded to silicon include an alkoxy group, a halogen, an acetoxy group, and the like. Usually, an alkoxy group such as a methoxy group and an ethoxy group, and chlorine are preferably used. For example, a trimethylsilylating agent, alkylsilanes, arylsilanes, fluoroalkylsilanes and the like can be mentioned. *

In the present invention, the hydrophilic fine particles may be hydrophobized to make the surface hydrophobic. *

In the present invention, it is preferable to perform a hydrophobizing treatment by a dry method. Here, the hydrophobizing treatment by dry means that the hydrophilic fine particles and the hydrophobizing agent are reacted in the gas phase. As the hydrophobizing agent, monomethyltrichlorosilane, dimethyldichlorosilane, hexamethyldisilazane, silicone oil, or the like can be used. For example, silicon dioxide synthesized at high heat can be hydrophobized in a fluidized bed using dimethyldichlorosilane. The hydrophobization reaction is preferably performed at a temperature of 400 to 600 ° C. The hydrophobizing treatment by wet means that the hydrophilic fine particles and the hydrophobizing agent are reacted in a solution. It should be noted that the degree of hydrophobicity of the fine particles having a hydrophobic surface is preferably designed as appropriate according to the material of the object to be coated and the type of organic solvent used. *

Examples of the hydrophobic silica containing a methyl group on the silica surface include, for example, a trade name “Leolosil HM20S” (manufactured by Tokuyama Corporation, average primary particle size 12 nm), and a trade name “Leolosil HM30S” (produced by Tokuyama Corporation, average Primary particle diameter 7 nm), trade name “Leoroceal HM40S” (manufactured by Tokuyama Corporation, average primary particle diameter 7 nm), trade name “Leoroceal DM30S” (manufactured by Tokuyama Corporation, average primary particle diameter 7 nm), trade name “Leolosil” ZD30S "(manufactured by Tokuyama Co., Ltd., average primary particle diameter 7 nm) and the like can be obtained commercially. *

The coating liquid of the present invention can further contain a coupling agent. Examples of the coupling agent used in the present invention include silane coupling agents, titanate coupling agents, aluminate coupling agents, zirconia coupling agents and the like. These coupling agents may be used alone or in combination of two or more. Examples of silane coupling agents include fluoroalkyl silanes (heptadecafluorodecyltrimethoxysilane, trifluoropropyltrimethoxysilane, etc.), alkyl silanes (decyltrimethoxysilane, etc.), and aluminate coupling agents. Examples thereof include alkyl acetoacetate aluminum diisopropylate. *

For example, as a silane coupling agent, trade name “TSL8233” (heptadecafluorodecyltrimethoxysilane, manufactured by Momentive), trade name “KBM-7103” (trifluoropropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) ), Trade name “KBM-3103” (decyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be obtained commercially. *

For example, as the titanate coupling agent, the trade name “Plenact 38S” (manufactured by Ajinomoto Fine Techno Co., Ltd.), and as the aluminate coupling agent, the trade name “Plenact AL-M” (alkyl acetate aluminum diisopropylate). As a zirconia-based coupling agent, a trade name “KENRIACT NZ01” (manufactured by Kenrich Co., Ltd.) and the like can be obtained commercially. *

The amount of fine particles having hydrophobic surfaces is preferably in the range of 0.1% by mass or more and 15.0% by mass or less in the coating solution, and in the range of 1% by mass or more and 5% by mass or less. More preferably it is. This is because sufficient water repellency may not be obtained if the amount of fine particles added is less than 0.1% by mass, and transparency may be inferior if it exceeds 15.0% by mass. *

The coating liquid of the present invention is formed using an organic solvent containing a hydrophobic solvent of 65% by mass or more in the total organic solvent. The organic solvent functions as a solvent for stably dispersing fine particles and the like. *

As the organic solvent used in the present invention, either a polar organic solvent or a nonpolar organic solvent can be used. Examples of the organic solvent preferably used in the present invention include methyl alcohol, ethyl alcohol, isopropyl alcohol, allyl alcohol, ethylene glycol, propylene glycol, 3-methoxy-3-methyl-1-butanol, and 1-methoxy-2-. Polar solvents such as alcohols such as propanol, ketones such as acetone and ethyl methyl ketone, ethers such as dimethyl ether, ethyl methyl ether, diethyl ether and dibutyl ether, esters such as ethyl acetate, hexane, n- Nonpolar solvents such as hexane, heptane, isooctane and the like can be mentioned. *

In the present invention, the “hydrophobic solvent” means an organic solvent that does not substantially dissolve water. Examples of the hydrophobic solvent used in the present invention include alkanes having 5 to 16 carbon atoms, alkenes, cycloalkanes, aromatics, and mixtures thereof, fluorine-based solvents, cyclic silicones (decamethylcyclohexane). Pentasiloxane, octamethylcyclotetrasiloxane, etc.), low-viscosity silicone oil (dimethylsilicone oil, etc.), and the like.

For example, as the above mixture, trade name “Isopar C” (octane> 95, heptane <5, manufactured by ExxonMobil), trade name “Isopar E” (octane 60-70, nonane 30-40, manufactured by ExxonMobil) , Trade name “Isopar G” (manufactured by ExxonMobil Co., Ltd.), etc., as fluoro solvents, hydrofluoroether (trade name “Novec HFE7100”, manufactured by Sumitomo 3M Ltd.), trade name “Bertrel” (Mitsui DuPont)・ Fluorochemical Co., Ltd.), etc., as cyclic silicones, trade name “TSF405” (decamethylcyclopentasiloxane, manufactured by Momentive), trade name “TSF404” (octamethylcyclotetrasiloxane, manufactured by Momentive), Product name “KF995” (decamethylcyclopentasiloxane, Shin-Etsu Chemical) Ltd.) and the like, and as the dimethyl silicone oil, or the like are available as trade name "KF96-1.5cst" manufactured (manufactured by Shin-Etsu Chemical Co.,) commercially. *

To the coating liquid of the present invention, additives that are usually used in general coating liquids and the like can be added within a range that does not impair the effects of the present invention. For example, ultraviolet absorbers, antioxidants, Coloring agents, fragrances, preservatives, acids, alkalis and the like can be added. *

In the present invention, it is preferable that fine particles having a hydrophobic surface and an average primary particle size of 100 nm or less are dispersed in an organic solvent by a cavitation action. Here, in order to cause the cavitation action, for example, fine particles are put in an organic solvent and dispersed by using an ultrasonic disperser or the like. The fine particles dispersed by the cavitation action exhibit unexpected super water repellency, but this mechanism is not clear. When an organic solvent is irradiated with ultrasonic waves, a high pressure portion and a low pressure portion appear, and a gas dissolved in water is generated as a cavity (bubble). It is considered that the bubbles are instantaneously contracted and broken to disperse the hydrophobic fine particles in a good state or have some action on the fine particles themselves. In addition, super-water repellency may be exhibited even when dispersed by a disperser such as a homogenizer, but adjustment is necessary in consideration of the transparency of the coating film to be formed. *

For example, a fine particle having a hydrophobic surface and, if necessary, a coating liquid in which a binder or a coupling agent is dispersed in a solvent are applied to the surface of an object to be coated such as glass or mirror, and then dried. Thus, water repellency can be imparted to the object to be coated (coating object). Here, the fine particles adhere to the surface of the object to be coated and form irregularities. The unevenness serves to reduce the contact point between the glass and the water droplet. Accordingly, it is possible to achieve super water repellency such that the contact angle of water drops is 150 ° to 175 °. *

For example, a component that forms a transparent body when dissolved in an organic solvent and dried serves as a binder. The components used in the present invention to form a transparent body when dissolved in an organic solvent and dried are dimethyl, methylphenyl, methylhydrogen, amino-modified, epoxy-modified, epoxy polyether-modified, carboxyl-modified, carboxyl polyether Modified, alcohol-modified, alkyl-modified, alkyl-aralkyl-modified, alkyl-aralkyl polyether-modified, polyether-modified, fluorine-modified silicones and other silicones, phenylmethyl-based resins, methyl-based resins, resins such as modified resins, polyolefin-based Resins, vinyl resins, polyester resins, acrylic resins, epoxy resins, urethane resins, etc., anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants Surfactants such as polyvinyl pyrone Synthetic polymers such as don, polyvinyl alcohol, polyether copolymer, polyacrylamide, polyacrylic acid, etc., higher alcohols, higher fatty acids, silica inorganic coating agents, silazane inorganic coating agents, rubbers such as silicone rubber And polysaccharides such as starch, glycogen and cellulose, and minerals such as smectite. Examples of the anionic surfactant include alkylbenzene sulfonic acid, α-olefin sulfonic acid, alkane sulfonic acid, alkyl sulfate, alkyl polyoxyethylene sulfate, alkyl phosphate, long chain fatty acid, α-sulfo fatty acid ester and salts thereof. Examples of the cationic surfactant include alkyl trimethyl ammonium salt, dialkyl dimethyl ammonium salt, and alkyl dimethyl benzyl ammonium salt. Nonionic surfactants include alkyl polyoxyethylene ether, fatty acid diethanol amino acid, and the like. And amphoteric surfactants include dimethylalkylamine oxide, N-alkylbetaines, imidazoline derivatives, and the like. *

However, in the present invention, the surface of the object to be coated is hydrophobic, and when the surface is not hydrophobic, it is preferable to make it hydrophobic in advance. As a method for making the surface of the coating object hydrophobic in advance, it is not particularly limited before coating operation (if it is before coating operation, it may be just before, several hours, several days, or even longer time may elapse). In other words, the surface of the object to be coated (coating object) is subjected to a hydrophobic treatment. For example, after making the surface of the coating object hydrophilic, a hydrophobic treatment can be applied to the surface of the coating object by applying a water repellent or the like. For example, when the glass surface is hydrophobized, the glass surface is polished with a glass cleaner to make the glass surface hydrophilic, and then sprayed with a glass coat G3 manufactured by Carmate Co., Ltd. Spread out and leave at room temperature for 24 hours. In this way, the glass surface can be made hydrophobic. In addition, even when the coating object is not glass, the above method can be appropriately applied and used. *

A method for applying the coating liquid of the present invention is not particularly limited, and a general method can be adopted. Examples thereof include a flow coating method, a dip coating method, a spray coating method, a gravure coating method, a roll coating method, a bar coating method, and a screen printing method. Alternatively, the impregnated body may be impregnated with a coating solution and applied. However, when using an impregnated body, use an impregnated body that is hydrophobic (does not absorb water, for example, does not absorb water for 10 seconds when water is dropped onto an impregnated body placed horizontally). is required. In the present invention, the above coating methods may be used in appropriate combination. *

The coating liquid of the present invention is applied to the object to be coated (object) by the above method and then dried. The drying temperature is preferably 0 ° C. to 100 ° C., and the drying time is preferably 1 minute to 1 hour. . *

The coating liquid of the present invention can be applied to various coated objects. Examples of coated objects to be coated include glass such as tempered glass, non-alkali glass and quartz glass, metals such as iron, aluminum, stainless steel and copper, plastics such as polyolefin resin, polyester resin, acrylic resin and polycarbonate. , Stones, concrete and the like. *

The coating liquid of the present invention can be coated on, for example, building window glass, exterior light glass, vehicle window glass, automobile side mirrors, sunglasses, window glass for various instruments, bathroom mirrors, etc. It can be used for exterior walls and roofs of buildings, fences, bodies, mirrors and wheels of automobiles, aircraft and ships. A super-water-repellent film is formed on the coating surface formed by coating and drying the coating liquid of the present invention, preventing adhesion of water droplets, dust, etc., maintaining aesthetics and ensuring visibility. can do. Also, if a super-water-repellent film is formed on the surface of parts that are subject to water droplets unnecessarily, such as heat exchangers in air conditioners, water droplets can be prevented, airflow resistance can be reduced, and A decrease in conductivity can be prevented. In addition, if a super water-repellent coating is formed on a parabolic antenna or an electric wire, condensation and icing can be prevented. Furthermore, according to the present invention, since a transparent coating film can be formed, it can be preferably used for window glass, road mirrors, road signs, signboards and the like of high-rise houses. *

According to the present invention, excellent super water repellency can be realized. Moreover, durability can be improved by mix | blending a binder.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples, and various applications are possible without departing from the technical scope of the present invention. In addition, each Example and each comparative example measured and evaluated by the method shown below. *

(1) Evaluation of super water repellency For evaluation of super water repellency, the initial water droplet contact angle was measured as follows. Using a CA-DT contact angle meter manufactured by Kyowa Interface Science Co., Ltd., a 2 μL water droplet was dropped on the water-repellent film of the sample glass in the atmosphere (about 25 ° C.), and the static contact angle of the water droplet was measured. . The super water repellency was evaluated based on the following evaluation criteria. (Evaluation criteria) ○ 140 ° or more △ 130 ° or more, less than 140 ° x less than 130 °

(2) Evaluation of finish (transparency) The water-repellent film was visually observed to evaluate the transparency. However, the evaluation criteria were the following three-level evaluation. (Evaluation criteria) ○ Completely transparent △ Appears slightly white when viewed from an angle, but has no practical problem × Appears white when viewed from the front

In the following examples and comparative examples, the following materials were used. “Lerosil HM20S”: Hydrophobic silica, solid content 100%, average primary particle size 12 nm, manufactured by Tokuyama Co., Ltd. “Lerosil HM30S”: Hydrophobic silica, solid content 100%, average primary particle size 7 nm, manufactured by Tokuyama Co., Ltd. “Lerosil HM40S”: hydrophobic silica, solid content 100%, average primary particle diameter 7 nm, manufactured by Tokuyama Corporation “Leosileal DM30S”: hydrophobic silica, solid content 100%, average primary particle diameter 7 nm, manufactured by Tokuyama Corporation “Lerosil ZD30S”: Hydrophobic silica, solid content 100%, average primary particle size 7 nm, Tokuyama “TSL8233”: fluoroalkylsilane, heptadecafluorodecyltrimethoxysilane, Momentive “KBM-13”: methyl Trimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd. BM-22 ": Dimethyldimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd." KBE-103 ": Phenyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd." KBM-3103 ": Decyltrimethoxysilane, Shin-Etsu Chemical Co., Ltd. ) “KBM-7103”: trifluoropropyltrimethoxysilane, “SR2405” manufactured by Shin-Etsu Chemical Co., Ltd., silicone resin solution, “Unidyne TG-658” manufactured by Dow Corning Toray, fluorinated water and oil repellent, Daikin Industries “TSF404” manufactured by Co., Ltd .: cyclic silicone (octamethylcyclotetrasiloxane), “TSF405” manufactured by Momentive: cyclic silicone (decamethylcyclopentasiloxane), “KF995” manufactured by Momentive: cyclic silicone (decamethylcyclopentasiloxane) “KF96-1.5cst” manufactured by Shin-Etsu Chemical Co., Ltd .: dimethyl silicone oil, IPA manufactured by Shin-Etsu Chemical Co., Ltd .: alcohol solvent (isopropyl alcohol) ethanol: alcohol solvent (ethyl alcohol) nonane: petroleum solvent (Nonane) n-decane: Petroleum solvent (normal decane) “Isopar G”: Isoparaffin hydrocarbon, manufactured by ExxonMobil

(Example 1) Hydrophobic silica having a hydrophobic surface and a particle diameter of about 7 nm (trade name “Leolosil HM30S”, solid content 100%, manufactured by Tokuyama Corporation) 2.0 mass% is obtained by isooctane 80.0. A hydrophobic silica dispersion is prepared by placing in a solvent comprising 1% by mass and 18.0% by mass of isopropyl alcohol (hereinafter also referred to as “IPA”) and dispersing for 1 hour at a frequency of 44 kHz using an ultrasonic disperser. did. The prepared hydrophobic silica dispersion was applied onto a glass plate (soda lime glass) having a thickness of 2.0 mm × length 75 mm × width 150 mm using an impregnated body (PP nonwoven fabric) (impregnation ratio = 400%). The glass substrate (sample glass) having a water-repellent film was prepared by naturally drying at 25 ° C. for 15 minutes to form a film. However, the surface of the slide glass plate was previously subjected to the following hydrophobization treatment, and coating was performed under two types of coating conditions (DRY, WET). That is, i) DRY: the glass substrate surface was dried, and ii) WET: the glass substrate surface was coated with water droplets. In addition, as the hydrophobizing treatment, first, the glass substrate surface is polished with a professional glass water spot cleaner P1 (manufactured by Carmate Co., Ltd.) to make the glass surface hydrophilic. The product was spray-coated and spread evenly, and then allowed to stand at room temperature (25 ° C.) for 24 hours. In addition, the temperature of the glass substrate at the time of coating, the temperature of the coating liquid, and the water temperature at the time of WET were all adjusted to 25 ° C.

About the water-repellent film of the obtained sample glass, the initial finish (transparency) was visually evaluated. Moreover, based on the said measuring method etc., the initial water droplet contact angle was measured as super-water-repellent evaluation. The results are shown in Table 1. However, in the evaluation of super water repellency, an evaluation criterion “◯” or higher was regarded as an acceptable level, and in the evaluation of finish (transparency), an evaluation criterion “Δ” or larger was regarded as an acceptable level. *

(Examples 2 to 30, Comparative Examples 1 to 21) A hydrophobic silica dispersion (coating solution) was prepared in the same manner as in Example 1 except that the composition of the coating solution was changed as shown in Tables 1 to 9. As for the glass substrate, as shown in Tables 1 to 9, the glass surface was hydrophobized (or not hydrophobized), and a coating solution was applied thereto to prepare a sample glass. About the obtained sample glass, the same measurement and evaluation as Example 1 were performed. The results are shown in Tables 1 to 9. However, as an application method of the coating liquid, when using an impregnated body, the impregnated body (for example, non-woven fabric) is impregnated with the coating liquid so that the impregnation ratios shown in Tables 1 to 9 are obtained. It apply | coated to the glass substrate fixed to 30 degree | times. In this case, the coating was repeated twice. In the case of the aerosol method, coating was performed by directly spraying on a glass substrate fixed at an inclination of 30 degrees. In the case of the flow coating method, coating was performed by allowing the liquid to flow on a glass substrate fixed at an inclination of 30 degrees. *

As is apparent from Tables 1 to 5, it was found that the coating films using the coating solutions of Examples 1 to 30 were excellent in transparency and had super water repellency. In addition, the coatings using the coating liquids of Examples 1 to 30 have excellent transparency and excellent super water repellency even when coating is performed with water droplets on the surface of the object to be coated. there were. *

On the other hand, as is apparent from Tables 6 to 9, when the coating film formed by Comparative Examples 1 to 21 is coated with water droplets on the surface of the object to be coated, it is super water-repellent. The evaluation was found to be less than the acceptable level.

The coating composition of the present invention can be effectively used in places where it is necessary to impart super water repellency to buildings, automobiles, aircraft, ships and the like. In particular, since a film having super water repellency can be formed without complicated steps even in the presence of moisture, it can be used particularly effectively even in a portion that requires application in the rain.

Claims

A coating liquid in which fine particles having a hydrophobic surface and an average primary particle size of 100 nm or less are dispersed in an organic solvent containing a hydrophobic solvent in an amount of 65% by mass or more in all organic solvents is applied to an object having a hydrophobic surface. A coating film forming method, comprising: forming a film on the surface of the object by processing.
2. The method of forming a coating film according to claim 1, wherein the object having a hydrophobic surface is subjected to a hydrophobic treatment on the surface of the hydrophilic object to make the surface hydrophobic.
3. The coating film forming method according to claim 1, wherein the coating liquid is applied to the object using a hydrophobic impregnated body. 4.
The coating film forming method according to claim 1, wherein the coating is performed by an aerosol method or a flow coating method.
The coating film forming method according to claim 1, wherein the fine particles having hydrophobic surfaces are hydrophobic silica.
A coating liquid comprising fine particles having a hydrophobic surface and an average primary particle size of 100 nm or less dispersed in an organic solvent containing a hydrophobic solvent in an amount of 65% by mass or more based on the total organic solvent.
The coating liquid according to claim 6, wherein the fine particles having hydrophobic surfaces are hydrophobic silica.