JP2000262964A - Formation of hydrophilic coating film and coated article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of simply preparing a coating film having excellent durability and high hydrophilicity and to provide a coated article provided with the hydrophilic coating film obtained by the method. SOLUTION: A coating film of petal type alumina A, a coating film of metal oxide B having a function as a photodegradation catalyst and a coating film of polysiloxane C are successively formed to prepare a multilayer coating film on a base material and the coated article is provided with the hydrophilic coating film formed by the method as a top coat layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a novel and useful hydrophilic film and a coated article provided with a hydrophilic film obtained by the method as a top coat layer.

More specifically, after a metal oxide film having a function as a photodecomposition catalyst and a polysiloxane film are sequentially formed on a substrate to prepare a multilayer film, the multilayer film is activated. The present invention relates to a method for forming a hydrophilic film, which is characterized by irradiating an energy beam, and a coated article provided with a hydrophilic film prepared by the method as a top coat layer.

[0003] The hydrophilic coating thus prepared is used to prevent contamination of various outdoor articles such as exterior wall materials of buildings, outdoor structures such as bridges and tanks or vehicles such as automobiles, and coolers and the like. For hydrophilicity of fins such as aluminum fins used for outdoor units and indoor units for heat exchange, for prevention of fogging of various glasses and mirrors used indoors,
Can be used effectively.

Further, it is possible to obtain a film having both a highly hydrophilic portion and a highly water repellent portion by performing partial masking upon irradiation with active energy rays.
The present invention can be effectively used for uses such as a medium for image formation.

[0005]

2. Description of the Related Art Heretofore, as a method for forming a hydrophilic film, there have been mentioned (1) a method of preparing a polymer by crosslinking a polymer containing a hydrophilic group such as a carboxylate group, a sulfonate group or a polyoxyalkylene group. Or
(2) As described in Japanese Patent No. 2756474, a coating agent comprising metal oxide fine particles having a function as a photo-oxidation catalyst such as crystalline titanium oxide and a binder such as silicone is applied to a substrate. After that, there is a method of making the surface hydrophilic by light irradiation, and the like.

However, among these methods, (1)
The hydrophilic film obtained by the method of (1) has a problem that it is inferior in durability and the hydrophilicity is impaired in a short period of time. There is a problem that a complicated process of preparing a coating agent from fine particles having a function and a binder has to be performed.

[0007]

SUMMARY OF THE INVENTION However, the present inventors have started research to eliminate all the various problems in the conventional technology as described above.

Accordingly, an object of the present invention is to provide a method for easily preparing a highly hydrophilic film having excellent durability, and to provide a hydrophilic film obtained by such a method. An object of the present invention is to provide a coated article provided as a top coat layer.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a metal oxide film having a function as a photolysis catalyst and a polysiloxane film have been sequentially formed on a substrate. After forming and preparing a multilayer coating, the coating having a high degree of hydrophilicity can be obtained by irradiating the multilayer coating with active energy rays. It has been found that a coated article provided as a coat layer is excellent in various performances and durability derived from surface hydrophilicity such as exposure contamination resistance, anti-fogging property, water flow-down property, and the present invention will be solved. Here, the present invention has been completed with the assurance that the above-mentioned problem can be solved brilliantly.

That is, the present invention provides

1. Petal-like alumina (A) film on base material, metal oxide (B) having function as photolysis catalyst
A film of polysiloxane (C) and a film of polysiloxane (C) are sequentially formed to prepare a multilayer film, and then the multilayer film is irradiated with an active energy ray.

2. The above-mentioned polysiloxane (C) film has at least one hydrolyzable group bonded to a silicon atom.
And an organosilane compound and / or a silicate compound having at least one monovalent organic group bonded to a silicon atom, or a hydrolysis product of the organosilane compound and / or the silicate compound. A method for forming a hydrophilic film according to 1 above,

3. The method for forming a hydrophilic film according to the above 1, wherein the metal oxide (B) is crystalline titanium oxide,

4. The method for forming a hydrophilic film according to any one of the above 1 to 3, wherein the irradiation with active energy rays reduces the contact angle between the hydrophilic film and water to 20 degrees or less.

[0015] 5. The method for forming a hydrophilic film according to any one of the above 1 to 4, wherein the active energy ray is an ultraviolet ray, and

6. A coated article provided with a hydrophilic coating prepared by the method described in any one of 1 to 5 above as a top coat layer.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION
It will be described in detail. First, the hydrophilic film referred to in the present invention refers to a film having a hydrophilicity of about 50 ° or less, preferably 40 ° or less, particularly preferably 20 ° or less as the contact angle with water.

As the substrate used for forming such a hydrophilic film, various known and commonly used substrates can be used. Particularly typical examples of such a substrate include various metal substrates, inorganic substrates and plastic substrates.

Among these various substrates, typical examples of the metal substrate include various metals such as iron, nickel, aluminum, chromium, zinc, tin, copper and lead; and stainless steel and brass. Alloys of various metals; various metals as described above, such as various surface-treated metals subjected to plating, chemical conversion treatment, and the like.

The inorganic substrate is mainly composed of an inorganic material typified by silicates such as cement, calcium silicate, etc., gypsum, asbestos, ceramics and the like. What is concrete, cement mortar, gypsum plaster, dolomite plaster, lightweight cellular concrete (ALC), asbestos cement board, glass fiber reinforced calcium silicate board, gypsum board,
Various things such as pottery, porcelain, alumina panels, silica panels, tiles or glass are mentioned.

Typical examples of the plastic substrate include films and molded articles of a thermoplastic resin having excellent heat resistance such as fluororesin, polyether sulfone, polyether ketone, polyphenylene oxide, polyphenylene sulfide, and polyimide; And crosslinked films and crosslinked molded articles having excellent heat resistance obtained from various thermosetting resins such as unsaturated polyester resins, phenolic resins, epoxy resins, and silicone resins.

In carrying out the method of the present invention, since the metal oxide (A) having a function as a photolysis catalyst can be fired at a high temperature when a film is formed, generally, the above-mentioned various kinds of materials are used. Among the substrates, it is particularly preferable to use an inorganic substrate having excellent heat resistance, such as metals, ceramics, and glass.

Further, in the present invention, a substrate obtained by applying a paint having excellent heat resistance such as a water glass type or an alkyl silicate type to the above-mentioned various substrates to form a cured film is used as the substrate. You can also.

In the method of the present invention, the petal-like alumina (A) film formed as the first layer on the substrate is such that the surface layer of the alumina film is subjected to the peptizing action of hot water or hot steam, This refers to a film having minute pore-shaped voids in which alumina having a petal-like structure is randomly gathered. In order to form such a petal-like alumina film, for example, a method described in J. Am. Ceram. Soc. Japan, V
ol. 103, no. 6, 582-585 (199
5), Proc. of XVII, Inter. Con
grees on Glass, Vol. 4,445-
449 (Beijing, China, 1995), N
ew Glass, Vol. 12, No. 2,42-4
5 (1997), JP-A-9-202,649, JP-A-9-202,650, JP-A-9-202,651, and the like.

That is, the film of petal-like alumina (A) is made of, for example, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum tri-se
A sol solution obtained by hydrolyzing aluminum alkoxides such as c-butoxide and aluminum tri-tert-butoxide in the presence of a chelating agent such as acetoacetate or acetylacetone is used as a base. It can be produced by applying to a material and baking at a high temperature to prepare an alumina gel film, treating it with hot water or heated steam, and baking at a high temperature.

By providing such a petal-shaped alumina film, the water repellency of the multi-layer coating before irradiation with active energy rays can be further increased, so that a patterned film having both a highly water-repellent portion and a highly hydrophilic portion is obtained. It is also effective for applications that use painted articles that have been made.

In the method of the present invention, a metal oxide (A) film having a function as a photolysis catalyst is formed as a second layer on a petal-like alumina (A) film provided on a substrate. Is done. Typical examples of the metal oxide (A) include crystalline titanium oxides such as anatase-type titanium oxide and rutile-type titanium oxide, zinc oxide, tin oxide, tungsten oxide, bismuth oxide, and oxides of titanium oxide. Various metal oxides such as diiron are exemplified. Among them, preferred is crystalline titanium oxide, and particularly preferred is anatase-type titanium oxide.

In order to form a film of crystalline titanium oxide as one of the films of the metal oxide (A) on a base material, finely divided crystalline titanium oxide prepared in advance is an essential component. It is possible to apply a method of forming a film by applying a coating agent containing the same, a method of coating a precursor of crystalline titanium oxide on a substrate surface, and then converting the precursor to crystalline titanium oxide by firing at a high temperature. Although it is possible, the method is particularly preferable from the viewpoint of forming a more uniform film.

As a method of forming a crystalline titanium oxide film by the above-mentioned method, a coating agent is prepared from a titanium alkoxide or a titanium chelate compound, and the coating agent is applied to a base material to form a titanium hydroxide or a titanium chelate. Preparing a thin film of the compound,
A method of firing at a temperature of about 400 ° C. or more, and applying an amorphous titanium oxide generated by irradiating an electron beam to a target of titanium metal in an oxidizing atmosphere, and then depositing the titanium oxide on a substrate at about 400 ° C.
There are the above-mentioned methods of firing at a high temperature, and of these, the former method is simpler.

Representative examples of titanium alkoxide used for preparing crystalline titanium oxide by the following method include titanium tetramethoxide, titanium tetraethoxide, titanium tetraisopropoxide, and titanium tetra-n. -Propoxide, titanium tetra-n-butoxide, titanium tetra-sec-butoxide, titanium tetra-tert-butoxide or oligomers of titanium alkoxide obtained by partially hydrolyzing and condensing the above-mentioned various titanium alkoxides. Can be

Typical titanium chelate compounds used in the method include titanium mono (acetylacetonate) tri-n-butoxide, titanium tetrakis (acetylacetonate), and titanium tetrakis (ethylacetoacetate). And compounds such as titanium bis (acetylacetonate) diisopropoxide, titanium bis (ethylacetoacetate) di-n-butoxide, and titanium mono (benzoylacetonate) tri-n-butoxide.

In order to prepare a coating agent from the titanium alkoxide or titanium chelate compound as described above, it is necessary to dissolve the various compounds described above in various known and commonly used organic solvents and use the compound as it is. I can do it. In addition, among various alcohols and the like, a solution obtained by dissolving the above-described compound in a water-soluble solvent is added with water to partially or completely hydrolyze to prepare a coating agent. Is also good.

As the organic solvent used for preparing the above-mentioned coating agent, various known and commonly used ones can be used. Representative examples thereof include methyl alcohol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, iso-butyl alcohol, sec-butyl alcohol, ethylene glycol, and ethylene glycol-mono-n. Alcohols such as -propyl ether; various aliphatic or alicyclic hydrocarbons such as n-hexane, n-octane, cyclohexane, cyclopentane and cyclooctane;

Various aromatic hydrocarbons such as toluene, xylene and ethylbenzene; ethyl formate, ethyl acetate, n-butyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-butyl ether Various esters such as acetate; various ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone;

Dimethoxyethane, tetrahydrofuran,
Various ethers such as dioxane and diisopropyl ether; various chlorinated hydrocarbons such as chloroform, methylene chloride, carbon tetrachloride, and tetrachloroethane; various chlorinated hydrocarbons such as N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and ethylene carbonate Aprotic polar solvents and the like.

Such a coating agent is used to facilitate the formation of a film by promoting the hydrolysis of an alkoxy group or the dehydration-condensation reaction of a hydroxyl group bonded to a metal atom. A catalyst can be added.

Representative examples of such catalysts include various inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid; various organic acids such as p-toluenesulfonic acid, monoisopropyl phosphate and acetic acid; and ammonium hydroxide. side,
Various inorganic bases such as sodium hydroxide and potassium hydroxide; various tin carboxylate salts such as dibutyltin diacetate and tin octylate; naphthenic acids of various metals such as iron, cobalt, manganese and zinc Metal carboxylate salts such as salts or octylates;

Various amine compounds such as 1,8-diazabicyclo [5.4.0] undecene-7 (DBU), tri-n-butylamine, dimethylbenzylamine, imidazole or 1-methylimidazole; tetramethyl Various quaternary ammonium salts such as ammonium salts, tetrabutylammonium salts, and trimethyl (2-hydroxypropyl) ammonium salts, and salts each having chloride, bromide, carboxylate, hydroxide, or the like as a counter anion. And the like.

When such a catalyst is added, the amount of the catalyst to be used is preferably about 10% of the titanium alkoxide or the titanium chelate compound contained in the coating agent.
0.0001 to 10 parts by weight, preferably 0.0005 to 3 parts by weight, particularly preferably 0.0005 to 1 part by weight with respect to 0 parts by weight. It is.

The coating agent obtained from a titanium alkoxide or a titanium chelate compound can be used as a clear coating agent containing no coloring agent, or can be used various known organic or inorganic coating agents. It can also be used as a coating agent containing pigments and dyes. Further, such a coating agent, if necessary, a leveling agent, a rheology control agent, an ultraviolet absorber, an antioxidant, various known and commonly used additives such as a plasticizer, or an acrylic resin, a vinyl resin, Various resins such as a polyurethane resin can also be blended and used.

Then, the coating agent thus prepared is applied to a substrate by a known and commonly used method, and is left at room temperature or is subjected to forced drying or baking at a temperature of about 60 to 300 ° C. to obtain titanium hydroxide. And a film of a titanium chelate compound or amorphous titanium oxide. Typical coating methods applied at this time include dip coating, spin coating, nozzle flow coating, reverse coating, flexo, printing, flow coating, bar coating, and air spraying. Alternatively, an airless spray method or the like can be used.

The thus-obtained titanium hydroxide, titanium chelate compound or amorphous titanium oxide film is calcined at a temperature of 400 to 600 ° C. to obtain an anatase type titanium oxide film.
By baking at a temperature exceeding ℃, a rutile type titanium oxide film can be obtained. And, as for the film thickness of these crystalline titanium oxide films, from the viewpoint of expressing a high degree of hydrophilicity and the point of crack resistance, 0.5 nm or more
It is preferably set to about 10 μm.

A third layer is formed on the petal-like alumina (A) film and the metal oxide (B) film having a function as a photolysis catalyst formed on the substrate as described above. By forming a film of polysiloxane (C), a multilayer film is prepared. Various known and commonly used methods can be applied to the formation of the polysiloxane (C) film. Specific examples of such a method include a method of applying a silane-based coating agent containing, as an essential component, a silane compound having at least one hydrolyzable group bonded to a silicon atom and hydrolyzing and condensing the silane compound. A polysiloxane-based coating agent containing, as an essential component, a previously prepared hydrolyzate of a silane compound having at least one hydrolyzable group bonded to a silicon atom or a polysiloxane which is a hydrolyzed condensate of the silane compound And apply
Further examples include a method of promoting condensation.

Examples of the silane compound used in the above-mentioned or the following method include an organosilane compound having at least one hydrolyzable group bonded to a silicon atom and at least one organic group bonded to a silicon atom, and various kinds of silane compounds. Silicate compounds.

In such an organosilane compound, a hydrolyzable group bonded to a silicon atom includes an alkoxy group, a substituted alkoxy group, an alkenyloxy group, an iminooxy group, an aryloxy group, an aralkyloxy group, a halogen atom or a hydrogen atom. And a group forming a hydroxyl group bonded to a silicon atom by hydrolysis, that is, a silanol group. And as a typical organic group bonded to a silicon atom, via a silicon-carbon bond,
An alkyl group, a fluoroalkyl group having 4 or less carbon atoms, an alkyl group to which various substituents are bonded, a cycloalkyl group,
Examples include an aryl group, an aralkyl group and an alkenyl group.

Representative examples of the alkyl group among the above organic groups include a methyl group, an ethyl group, an n-butyl group, an iso-butyl group, an n-octyl group, an n-dodecyl group and an n-octadecyl group. , N-eicosyl group, n
Linear or branched ones having 1 to 30 carbon atoms, such as -tricontyl group. Representative examples of the alkyl group having a substituent include a 3-glycidoxypropyl group, a 3- (meth) acryloyloxypropyl group,
And 3-substituted propyl groups such as 3-ureidopropyl group, 3-isocyanatopropyl group and 3-dimethylaminopropyl group. Typical examples of the fluoroalkyl group having 4 or less carbon atoms include 3,3,3-trifluoropropyl group and 4,4,4-trifluorobutyl group. Representative examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group. Representative examples of the aryl group include a phenyl group, a p-tolyl group, and a 1-naphthyl group. Representative aralkyl groups include benzyl, 2-phenylethyl and 1-phenylethyl groups. Representative examples of the alkenyl group include a vinyl group and an isopropenyl group.

At least one of the above hydrolyzable groups
Among the organosilane compounds having both an organic group and at least one organic group, those representative of those containing an alkoxy group or a substituted alkoxy group as a hydrolyzable group include methyltrimethoxysilane and methyltriethoxysilane. Methyl tri (2-methoxyethoxy) silane, n-butyltrimethoxysilane, n-octyltrimethoxysilane, n-dodecyltrimethoxysilane,
n-octadecyltrimethoxysilane, n-eicosyltrimethoxysilane, n-triacontyltrimethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltri-n-butoxysilane, n-propyltrimethoxysilane, n-butyl Trimethoxysilane, n-butyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri-n-butoxysilane, vinyltrimethoxysilane,
Vinyltriethoxysilane, vinyltri-n-butoxysilane, vinyltris (2-methoxyethoxy) silane or allyltrimethoxysilane, 2-trimethoxysilylethyl vinyl ether, 2-triethoxysilylethyl vinyl ether, 3-trimethoxysilylpropyl vinyl ether, Various organotrialkoxysilanes such as 3-triethoxysilylpropylvinylether, 3- (meth) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane Kind;

Dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-butoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, di-n-butyl Dimethoxysilane, di-n-butyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldi-
n-butoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, vinylmethyldimethoxysilane, 2- (methyldimethoxysilyl) ethyl vinyl ether, 3- (methyldimethoxysilyl) propyl vinyl ether, 3- (meth) acryloyloxypropylmethyl Various diorganodialkoxysilanes such as dimethoxysilane and 3-glycidoxypropylmethyldimethoxysilane; triorganomonoalkoxys such as trimethylmethoxysilane, triethylmethoxysilane, tert-butyldimethylmethoxysilane and cyclohexyldimethylmethoxysilane Silanes.

Examples of the organosilane compound containing various groups other than an alkoxy group or a substituted alkoxy group as a hydrolyzable group include the above-mentioned various alkoxysilane compounds in place of the alkoxy group or the substituted alkoxy group in place of the alkoxy group or the substituted alkoxy group. And various compounds into which a hydrolyzable group has been introduced.

Among the various organosilane compounds described above, it is particularly preferable to use a silane compound containing two or three hydrolyzable groups as a main component in view of the durability of the hydrophilic film. . In addition, those containing an alkoxy group or a substituted alkoxy group are particularly preferable as the hydrolyzable group from the viewpoint of easy handling.

Representative examples of the silicate compound as one of the silane compounds used in the above-described method or the method include methyl silicate, ethyl silicate, n-butyl silicate, 2-ethylhexyl silicate, and n-octyl silicate. , Various silicates containing an alkoxy group having about 1 to 18 carbon atoms such as n-dodecyl silicate and n-octadecyl silicate; substituted alkyl silicates such as tetra-2-methoxyethoxy silicate and tetra-3-methoxypropyl silicate Various types such as aralkyl silicates such as benzyl silicate and 2-phenylethyl silicate; The above-mentioned organosilane compound and silicate compound can be used alone or in combination.

The silane-based coating agent or polysiloxane-based coating agent used in the present invention can be prepared from the above-mentioned various silane compounds by various known and commonly used methods. That is, the silane compound is dissolved in various solvents as exemplified as those used in preparing the above-mentioned metal oxide (B) film, or the silane compound is partially hydrolyzed and condensed in the solvent. For example, a method of hydrolyzing or hydrolyzing and condensing can be applied. In preparing these coating agents, various catalysts as described above can also be added.

When such catalysts are added, they are used in an amount of 0.1 to 100 parts by weight of the silane compound or polysiloxane contained in the coating agent.
The range of 0001 to 10 parts by weight is preferably 0.
In the range of 0005 to 3 parts by weight, particularly preferably,
The range of 0.0005 to 1 part by weight is appropriate.

As described above, a polysiloxane-based coating agent is prepared from an organosilane compound and / or a silicate compound. The polysiloxane contains a silicon atom to which a methyl group or a phenyl group is bonded and has a functional group. Various commercially available silicone resins containing a silanol group or a methoxy group as a group can also be used.

The silane-based coating agent or polysiloxane-based coating agent used in the present invention may contain a leveling agent, a rheology control agent,
Known additives such as an ultraviolet absorber, an antioxidant or a plasticizer, or various resins such as an acrylic resin, a vinyl resin, or a polyurethane resin may be blended and used. .

The above-mentioned coating agent used in the present invention can be used as a clear coating agent containing no coloring agent, and various known organic or inorganic pigments and dyes can be used. Can also be used as a coating agent containing

The coating agent thus prepared is formed on the petal-like alumina film by applying various methods as exemplified as applied when preparing the above-mentioned metal oxide (B) film. Is applied on the metal oxide (B) film. Next, a film of polysiloxane (B) is obtained by leaving it at room temperature for about 1 to 10 days to dry it, or forcibly drying or baking at a temperature of about 60 to 300 ° C. for about 1 minute to 3 hours. I can do it.

As described above, the thickness of the polysiloxane (C) film formed is 0.5 nm to 1 in view of exhibiting a high degree of hydrophilicity and crack resistance.
It is preferably set to 0 μm, preferably about 1 nm to 5 μm.

By irradiating the thus obtained multilayer film with an active energy ray, a hydrophilic film can be formed. The irradiation conditions such as the type of the active energy ray to be irradiated and the irradiation time are as follows. With a contact angle of approximately 50 degrees or less, preferably 40 degrees or less, and most preferably 2 degrees or less.
What is necessary is just to set it so that it may become 0 degrees or less.

As the active energy ray, various kinds of well-known and commonly used active energy rays can be used, and typical examples thereof include visible light, ultraviolet light, excimer laser light, semiconductor laser light, electron beam and X-ray. Kimono.

As the radiation source for irradiating the active energy ray, a known and commonly used apparatus capable of generating each active energy ray may be used.
Sunlight can also be used as a source.

Among the various active energy rays described above, ultraviolet rays are particularly preferred.

The time for irradiating the active energy ray may be set to an optimum time according to the degree of hydrophilicity to be imparted to the film, the thickness of the film, the intensity of the radiation source, and the like. It may be about 10 minutes to 10 hours. However, when using sunlight as a radiation source, it may be possible for the first time to become hydrophilic by exposure for one day to one month.

The mechanism by which the hydrophilic film is formed by the method of the present invention has not been elucidated yet, but is contained in the polysiloxane film of the top coat layer due to the photolytic function of the metal oxide (B) film. It is presumed that decomposition of the organic group or alkoxy group occurs to form a hydrophilic silica-based film.

Next, a coated article provided with a hydrophilic film obtained by the method for forming a hydrophilic film of the present invention as a top coat layer will be described.

More specifically, such coated articles include automobiles, motorcycles, trains, bicycles, ships or airplanes or other transportation-related equipment each using a metal substrate as a substrate. Various parts using metal base or plastic base, etc. used for them; TV, radio, refrigerator, washing machine, cooler outdoor unit using metal base, plastic base, etc. as base Fin materials such as aluminum fins for heat exchange installed in indoor units or outdoor units of coolers or computers or other household appliances; various image forming media mainly using metal base materials Glass parts for vehicles such as windshields, rear glasses, side glasses, door mirrors, and glass products such as mirrors or window glasses of buildings.

Various building materials such as various inorganic tiles, metal roofing materials, inorganic outer wall materials, metal wall materials, metal window frames, metal doors or inner wall materials; Various outdoor structures such as road signs, guardrails, bridges, tanks, chimneys or buildings; and various coating films coated on various organic films such as polyimide resin films or fluororesin films.

Then, among these various coated articles,
Particularly preferred are various exterior building materials and various outdoor constructions in that the top coat layer is made hydrophilic to improve the exposure and contamination resistance; From the viewpoint, a fin material for heat exchange and various glass products can be mentioned.

Further, since the material can be significantly hydrophilized by irradiation with energy rays, a material for an image forming material utilizing the difference in hydrophilicity between the irradiated part and the unirradiated part is also mentioned as one of the coated articles of the present invention. Can be

[0070]

Next, the present invention will be described more specifically with reference examples, examples and comparative examples, but the present invention is by no means limited to these examples. In the following, all parts and percentages are by weight unless otherwise specified. In addition, the measurement of the contact angle with water, which is a measure of hydrophilicity, was about 1.7 on the film.
The measurement was carried out under a temperature condition of 25 ° C. in the atmosphere using a contact angle meter manufactured by Elma Co., Ltd. with a water droplet of μl placed thereon.

Reference Example 1 [Preparation Example of Coating Agent for Forming Petal-Like Alumina Film] A reaction vessel equipped with a stirrer, a thermometer, and a dropping funnel was prepared.
24.6 g (0.1 mol) of aluminum tri-sec-butoxide and 100.0 g (1.66 mol) of isopropanol were charged, and 13.0 g (0 mol) of ethyl acetoacetate was added while stirring at 30 ° C. .1 mol)
Was added dropwise over 10 minutes, and the mixture was stirred at the same temperature for 1 hour. Then, while stirring at the same temperature, a mixture consisting of 20 g (0.33 mol) of isopropanol and 7.2 g (0.4 mol) of water was added dropwise over 10 minutes. During the stirring, a coating agent for forming a petal-like alumina film was prepared. Hereinafter, this is referred to as coating agent (T-1).

Reference Example 2 [Preparation Example of Coating Agent for Forming Film of Metal Oxide (B)] In the same reaction vessel as in Reference Example 1, titanium tetra-n-
34.0 grams (0.1 mole) of butoxide and 691.1 grams (15.0 moles) of ethanol were charged.
Stirring was performed at 5 ° C. for 30 minutes. A mixture of 10.0 grams (0.1 mole) of acetylacetone and 46.1 grams (1.0 mole) of ethanol was then added to 3
It was dropped in 0 minutes. The mixture is further added for 25 hours for 2 hours.
Then, 1.8 g of a 0.01 N aqueous nitric acid solution was added thereto, followed by stirring for 1 hour to obtain a coating agent containing a titanium chelate compound bound with acetylacetone as a chelating agent. Was. Hereinafter, this is referred to as coating agent (T-2).

REFERENCE EXAMPLE 3 [Preparation Example of Coating Agent for Forming Polysiloxane (C) Film] In a reaction vessel similar to that of Reference Example 1, 41.7 g (0.1 mol) of n-octadecyltriethoxysilane was added. And 921.4 grams (20.0 moles) of ethanol and 3
2. While stirring at 0 ° C., a 0.02 N aqueous hydrochloric acid solution was added.
6 grams were added dropwise over 10 minutes. Continue at the same temperature for 5
Stirring was continued for a time to obtain a solution of the silane-based coating agent. Hereinafter, this is referred to as coating agent (T-3).

Reference Example 4 [Id.] Instead of 41.7 g of n-octadecyltriethoxysilane, 17.8 g (0.1 mol) of methyltriethoxysilane was used, and the amount of ethanol used was 92.
The reaction was carried out in the same manner as in Reference Example 3 except that the amount was changed to 1.4 g (20.0 mol) to obtain a solution of a silane-based coating agent. Hereinafter, this is referred to as coating agent (T-4).

Reference Example 5 [Id.] Instead of 41.7 g of n-octadecyltriethoxysilane, 19.0 g (0.1 mol) of vinyltriethoxysilane was used, and the amount of ethanol used was 92%.
The reaction was carried out in the same manner as in Reference Example 3 except that the amount was changed to 1.4 g (20.0 mol) to obtain a solution of a silane-based coating agent. Hereinafter, this is abbreviated as coating agent (T-5).

Reference Example 6 [Id.] Instead of 41.7 g of n-octadecyltriethoxysilane, 24.4 g (0.1 mol) of phenyltriethoxysilane was used, and the amount of ethanol used was 92%.
The reaction was carried out in the same manner as in Reference Example 3 except that the amount was changed to 1.4 g (20.0 mol) to obtain a solution of a silane-based coating agent. Hereinafter, this is abbreviated as coating agent (T-6).

REFERENCE EXAMPLE 7 [Same as above] In a reaction vessel similar to Reference Example 1, 17.8 g (0.1 mol) of methyltrimethoxysilane, 20.8 g (0.1 mol) of tetraethylsilicate and ethanol were added. Of 276.4 g (6.0 mol) was added, and 12.6 g of a 0.01 N hydrochloric acid aqueous solution was added dropwise over 20 minutes while stirring at 30 ° C. Subsequently, stirring was continued at the same temperature for 5 hours to obtain a solution of the silane-based coating agent. Hereinafter, this is abbreviated as coating agent (T-7).

REFERENCE EXAMPLE 8 [Same as above] In the same reaction vessel as in Reference Example 1, 32.1 g (0.1 mol) of n-butyl silicate and 230.
4 g (5.0 mol) was charged, and 1.8 g of a 0.02 N hydrochloric acid aqueous solution was added dropwise over 10 minutes while stirring at 50 ° C. Subsequently, stirring was continued at the same temperature for 5 hours, and then 230.4 g of ethanol (5.
0 mol) to obtain a solution of a silane-based coating agent. Hereinafter, this is referred to as coating agent (T-8).

Example 1 The coating agent (T-1) prepared in Reference Example 1 was degreased into a 2.5 cm × 2.5 cm × 0.1 cm soda lime glass plate using a dipping apparatus using a dipping apparatus. An alumina sol-based coating agent was applied by a coating method. After air drying, baking was performed at 400 ° C. for 10 minutes, and then immersed in boiling water for 10 minutes. Then 40
Baking was performed at 0 ° C. for 10 minutes to obtain a glass plate on which a petal-like alumina layer having a thickness of 200 nm was formed.

The coating agent (T-2) prepared in Reference Example 2 was applied to the glass plate on which the petal-shaped alumina layer was formed by dip coating, and baked at 500 ° C. for 30 minutes to give a film thickness of 2 nm. Anatase type titanium oxide film was formed. Next, the coating agent (T) prepared in Reference Example 3 was applied to the coated glass plate thus obtained.
-3) is applied by a dip coating method.
A heat treatment for 0 minutes was performed to form a polysiloxane film having a thickness of 2 nm to obtain a multilayer film.

The multi-layer coating thus prepared was coated with a 250 W ultra-high pressure mercury lamp “UIS-2” manufactured by Ushio Inc.
5102 "(wavelength of irradiation light: 250 to 450 nm), and ultraviolet irradiation was performed for 30 minutes from a distance of 5 cm. The contact angle of the coating with water before irradiation with ultraviolet light was 150 degrees, but after irradiation, it was 5 degrees or less, confirming that the coating was highly hydrophilic.

Examples 2 to 6 In the same manner as in Example 1 except that the coating agents (T-4) to (T-8) were used instead of the coating agent (T-3), soda lime glass was used. And the thickness is about 200
A multi-layer film was formed on which was formed a petal-shaped alumina film having a thickness of nm, an anatase-type titanium oxide film having a thickness of 2 nm, and a polysiloxane film having a thickness of about 2 nm. Each of the multilayer films was irradiated with ultraviolet rays in the same manner as in Example 1. The contact angles of the multilayer coating with water before and after irradiation with ultraviolet light are as shown in Table 1, and it was confirmed that all of the multilayer coatings were highly hydrophilized by ultraviolet irradiation.

[0083]

[Table 1]

Example 7 The procedure of Example 1 was repeated except that a degreased 2.5 cm × 2.5 cm × 0.01 cm stainless steel plate was used as the substrate instead of soda lime glass. Similarly, on both sides of the stainless steel plate, a thickness of about 2
A multilayer film was prepared in which a petal-like alumina film having a thickness of 00 nm, an anatase type titanium oxide film having a thickness of 2 nm, and a polysiloxane film having a thickness of about 2 nm were formed.

Using the same apparatus as in Example 1 on both sides of the obtained stainless steel plate on which the multilayer coating was formed,
In addition, ultraviolet irradiation was performed under the same conditions as in the same example. The contact angle of the coating with water before the UV irradiation was 145 degrees, and that after the irradiation was 5 degrees or less, confirming that the coating was highly hydrophilic by the irradiation.

[0086] Five stainless steel plates thus prepared were laminated to prepare a model product of a heat exchanger for an air conditioner. This model product was subjected to five repetitive tests in which one cycle consisted of 8 hours of immersion in water at 30 ° C. and 16 hours of drying at 80 ° C., and then a bridge (fog of water droplets between stainless steel plates) was sprayed. ) Was evaluated, no bridge formation was observed at all, and it was confirmed that water flowability was excellent. Therefore, a stainless steel plate provided with a hydrophilic film prepared as a top coat layer by the method of the present invention can be effectively used as a fin material for a heat exchanger.

Example 8 Instead of a glass plate subjected to a degreasing treatment, 2.5 cm × 2.
A film thickness was obtained in the same manner as in Example 1 except that a white porcelain tile of 5 cm × 0.3 cm was used as a base material, and a coating agent (T-4) was used instead of the coating agent (T-3). Is 80 nm petal-like alumina film, thickness is 2 nm
Anatase type titanium oxide film and film thickness of 2 nm
Thus, a porcelain tile on which a polysiloxane film was sequentially formed was obtained. Next, the obtained multilayer coating film was irradiated with ultraviolet rays using the same apparatus as in Example 1 and under the same conditions as in the same example. The contact angle of the coating with water before UV irradiation is 130
It was 5 degrees or less after irradiation in degrees, and it was confirmed that the film was highly hydrophilized by irradiation.

The obtained coated plate was set in a test machine for accelerating the resistance to rain dripping contamination, and an exposure test was performed outdoors. After exposure for 3 months, no contamination of the film was observed at all, and it was confirmed that the film had extremely excellent resistance to rain dripping contamination. Therefore, it has been clarified that an inorganic base material provided with a film formed by the method of the present invention as a top coat layer can be effectively used for building exterior and building material applications.

Example 9 Instead of a glass plate subjected to a degreasing treatment, 2.5 cm × 2.
A film thickness was obtained in the same manner as in Example 1 except that a 5 cm × 0.3 cm white porcelain tile was used as a base material, and a coating agent (T-7) was used instead of the coating agent (T-3). Was obtained in which a petal-shaped alumina film having a thickness of 80 nm, an anatase-type titanium oxide film having a thickness of 2 nm, and a polysiloxane film having a thickness of 2 nm were sequentially formed. The obtained coated plate was set on a tester for accelerating rain dripping contamination resistance, and an outdoor exposure test was performed. 6
After the exposure for one month, no contamination of the film was observed at all, and it was confirmed that the film had extremely excellent resistance to rain dripping contamination. Before the start of exposure, the contact angle of the multilayer coating was 123 degrees, but 6
It was found that the contact angle after a month of exposure had dropped to 10 degrees. This indicates that the hydrophilicity progressed even when exposed to sunlight outdoors, and the film was changed to a film having excellent resistance to rain dripping contamination.

[0090]

The method for forming a hydrophilic film according to the present invention is extremely practical in that a highly hydrophilic film having excellent durability can be easily obtained from a multilayer film having a high degree of water repellency. A coated article provided with such a hydrophilic coating as a top coat layer has excellent properties derived from the hydrophilicity of the coating, such as anti-fogging property, water flow-down property, and exposure contamination resistance. Further, it is also useful for applications used as a coated article having both patterns of a highly water-repellent portion and a highly hydrophilic portion, and is extremely useful.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C09D 5/00 C09D 5/00 Z L 183/04 183/04 F term (reference) 4D075 BB46Y CA34 CA37 CA39 DB07 DB13 DC03 DC05 DC13 DC16 EB43 EC02 4F006 AB39 AB74 BA10 CA04 CA08 EA03 4F073 AA01 BA33 BA52 BB01 CA45 4J038 AA011 DL031 HA211 NA06 PA17 PA19 PB05 PB06 PB07 PC02 PC04 PC08

Claims (6)

[Claims] 1. A petal-like alumina (A) film on a substrate, a metal oxide (B) having a function as a photolysis catalyst
And forming a film of polysiloxane (C) in order to prepare a multilayer film, and then irradiating the multilayer film with active energy rays. 2. The organosilane as described above, wherein the polysiloxane (C) film has at least one hydrolyzable group bonded to a silicon atom and at least one monovalent organic group bonded to a silicon atom. Compound and / or silicate compound, or the organosilane compound and / or
The method for forming a hydrophilic film according to claim 1, wherein the method is formed from a hydrolysis product of a silicate compound. 3. The method according to claim 1, wherein the metal oxide (B) is crystalline titanium oxide. 4. The method for forming a hydrophilic film according to claim 1, wherein the contact angle between the multilayer film and water is reduced to 20 degrees or less by irradiation with active energy rays. 5. The method for forming a hydrophilic film according to claim 1, wherein the active energy rays are ultraviolet rays. 6. A coated article provided with a hydrophilic coating prepared by the method according to claim 1 as a top coat layer.