JP2013023683A - Coating composition and article with coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition which exhibits super hydrophilicity with a contact angle of water of 5 degrees or less even in an environment without light since immediately after film production, and which forms a coating film excellent in durability, and to provide an article with the coating film, which exhibits an antifouling effect based on self purification capability (self cleaning) for a long period of time even in an environment of being continuously exposed to rain water (running water) in outdoor or the like.SOLUTION: The coating composition prepared by mixing: hydrophilic fumed silica (A1) with an average particle size of 1-40 nm; amorphous inorganic powder (A2) with an average particle size of 0.1-500 μm, and an apparent specific volume of 2-12 cm/g; and a binder (B) composed of at least one selected from a group of a resin (B1), a dialkoxysilane compound or a partially hydrolyzed condensate thereof (B21), and a tetraalkoxysilane compound or a partially hydrolyzed condensate thereof (B22), is used.

Description

  The present invention relates to a coating composition capable of forming a superhydrophilic coating film, and an article with a coating film having a coating film formed of the coating composition on the surface.

  Dirt adhering to the surface of outdoor buildings is naturally removed by rain water (running water), the surface of glass and mirrors is prevented from being fogged, and condensed water on the surface of aluminum fins in air conditioner heat exchangers is prevented to exchange heat. In order to obtain an effect such as improving the efficiency of the substrate, the surface of the substrate is highly hydrophilized.

  For example, Patent Document 1 discloses a hydrophilic antifouling coating composition comprising a water-dispersible silica sol neutralized with ammonia or a volatile amine, a water-soluble anionic and / or nonionic surfactant, and a water-soluble solvent. Yes. However, although the coating film obtained by using this composition has good initial hydrophilicity, the effect is temporary because the surfactant is easily dropped by rainwater (running water). However, there is a problem that hydrophilicity cannot be maintained.

  Patent Document 2 contains a hydrolyzate and / or partial hydrolyzate of an alkoxide, fine particle silica, a diluent solvent, and a surface tension modifier, and the fine particle silica has an average particle diameter of 4 nm to less than 20 nm. And a coating composition comprising a combination of two or more kinds of fine-particle silica having an average particle diameter of 20 nm to 150 nm. However, the coating film obtained using this coating composition is hydrophilic with a water contact angle of around 30 °, and has not reached super-hydrophilicity with a water contact angle of 5 ° or less. Therefore, there exists a problem that the antifouling effect by self-cleaning ability (self-cleaning) is inferior.

  Further, it is widely known that in a coating film containing an optical semiconductor such as titanium oxide, the surface of the coating film becomes hydrophilic due to photocatalytic action. However, such an effect is not obtained immediately after film formation, and there is a problem that the effect of improving hydrophilicity cannot be obtained because the photocatalytic action does not work in an environment without light.

JP 2006-265462 A JP 2010-144083 A

  The present invention has been made in view of the above circumstances, and exhibits superhydrophilicity in which the contact angle of water is 5 ° or less immediately after film formation even in an environment where light is not present, and is excellent in durability. With a coating film that can exhibit an antifouling effect due to self-cleaning ability (self-cleaning) for a long time even in an environment where it is continuously exposed to rainwater (running water) outdoors etc. Articles are provided.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that hydrophilic fumed silica having a small particle size in a specific range, and an amorphous inorganic powder having a large particle size in a specific range and an apparent specific volume in a specific range. When a coating composition formed by mixing a body and a binder is applied to various substrates and dried, it can exhibit a super hydrophilic property immediately after film formation and can form a coating film with excellent durability. The headline and the present invention were completed.

That is, the coating composition of the present invention comprises hydrophilic fumed silica (A1) having an average particle diameter of 1 to 40 nm; an average particle diameter of 0.1 to 500 μm, and an apparent specific volume of 2 to 12 cm ³ /. an amorphous inorganic powder (A2) that is g; a resin (B1), a dialkoxysilane compound represented by the following formula (1) or a partially hydrolyzed condensate (B21) thereof, and the following formula (2) It is formed by mixing at least one binder (B) selected from the group consisting of a tetraalkoxysilane compound represented by the formula (1) or a partially hydrolyzed condensate (B22) thereof.

Si (R ¹ ) (R ² ) (OR ³ ) (OR ⁴ ) (1)
(In the formula (1), R ¹ and R ² are each an alkyl group having 1 to 6 carbon atoms, an aminoalkyl group having 1 to 8 carbon atoms, or a glycidoxyalkyl group, and R ³ and R ⁴ are respectively (It is an alkyl group having 1 to 6 carbon atoms.)
Si (OR ⁵ ) (OR ⁶ ) (OR ⁷ ) (OR ⁸ ) (2)
(In Formula (2), R < ⁵ > -R < ⁸ > is a C1-C6 alkyl group, respectively.)

  The binder (B) is selected from the group consisting of the resin (B1); the dialkoxysilane compound or its partial hydrolysis condensate (B21) and the tetraalkoxysilane compound or its partial hydrolysis condensate (B22). It is preferable to use in combination with at least one kind of alkoxysilane compound or a partial hydrolysis condensate (B2) thereof.

The coating composition of the present invention is preferably the following composition (α) or composition (β), more preferably the composition (α).
(Α) The hydrophilic fumed silica (A1), the resin (B1), the alkoxysilane compound or a partial hydrolysis condensate (B2) thereof are mixed, and the hydrophilic fumed silica (A1) A composition obtained by mixing the alkoxysilane compound or a partially hydrolyzed condensate thereof (B2) with the amorphous inorganic powder (A2).
(Β) the hydrophilic fumed silica (A1) and the alkoxysilane compound or a partially hydrolyzed condensate (B2) thereof mixed and reacted; the resin (B1); and the amorphous A composition obtained by mixing high quality inorganic powder (A2).

  The article with a coating film of the present invention is characterized by having a coating film comprising the coating composition of the present invention on the surface.

According to the coating composition of the present invention, even in an environment where light is not present, a coating film that exhibits super hydrophilicity with a water contact angle of 5 ° or less immediately after film formation and that has excellent durability can be easily obtained. And can be formed efficiently.
The article with a coating film of the present invention can exhibit an antifouling effect due to self-cleaning ability (self-cleaning) for a long time even in an environment where it is continuously exposed to rainwater (running water) outdoors.

<Coating composition>
The coating composition of the present invention comprises hydrophilic fumed silica (A1); amorphous inorganic powder (A2); resin (B1), dialkoxysilane compound or partially hydrolyzed condensate thereof (B21), And a binder (B) comprising at least one selected from the group consisting of a tetraalkoxysilane compound or a partial hydrolysis condensate (B22) thereof. The coating composition of the present invention may further contain a diluent medium, a thickener, other additives, and the like as necessary.

(Hydrophilic fumed silica (A1))
The hydrophilic fumed silica is fumed silica having silanol groups which are hydrophilic groups on the surface. Further, fumed silica is silica produced by a gas phase reaction called a dry method, and is different from silica produced by a liquid phase reaction called a wet method (colloidal silica, silica gel, etc.). The primary particles having no pores are aggregated to form secondary particles and tertiary particles, which are fine particles having very high bulkiness.

The average particle diameter of the hydrophilic fumed silica (A1) is 1 to 40 nm, and 1 to 20 nm is preferable and 7 to 15 nm is more preferable from the viewpoint of hydrophilicity of the resulting coating film. When the average particle size of the hydrophilic fumed silica (A) is outside the range of 1 to 40 nm, it tends to be difficult to obtain.
The average particle diameter of the hydrophilic fumed silica (A1) is an average primary particle diameter obtained by measuring the particle diameters of 100 primary particles using a transmission electron microscope.

Commercially available products of hydrophilic fumed silica (A1) include AEROSIL 90G (average particle size 20 nm), AEROSIL 130 (average particle size 16 nm), AEROSIL 200 (average particle size 12 nm), AEROSIL 300 (average particle size 7 nm), AEROSIL 380 (average particle diameter 7 nm), AEROSIL 300CF (average particle diameter 7 nm), AEROSIL OX50 (average particle diameter 40 nm) (above, manufactured by Nippon Aerosil Co., Ltd.), and the like.
As the hydrophilic fumed silica (A1), one type may be used alone, or two or more types may be used in combination.

(Amorphous inorganic powder (A2))
Examples of the amorphous inorganic powder (A2) include silica, aluminum silicate, aluminum hydroxide, hydrotalcite, magnesium silicate, calcium silicate, a composite of magnesium oxide and aluminum oxide, silica and oxidation. Examples thereof include a composite of zinc, a composite of silica, zinc oxide and aluminum oxide, and silica and aluminum silicate are preferred from the viewpoint of the hydrophilicity, cost and availability of the resulting coating film.

The average particle diameter of the amorphous inorganic powder (A2) is 0.1 to 500 μm, preferably 0.1 to 200 μm, and more preferably 0.3 to 50 μm. When the average particle diameter of the amorphous inorganic powder (A2) is less than 0.1 μm, it tends to be difficult to obtain. When it exceeds 500 μm, the hydrophilicity of the coating film tends to decrease. Furthermore, the product stability of the coating composition tends to be poor.
The average particle diameter of the amorphous inorganic powder (A2) is an average primary particle diameter obtained by measuring the particle diameters of 100 primary particles using a transmission electron microscope.

Apparent specific volume of the amorphous inorganic powder (A2) is a 2~12cm ³ / g, preferably ^{2~10cm 3 / g, 4~10cm 3 /} g is more preferable. When the apparent specific volume is less than 2 cm ³ / g, the hydrophilicity of the coating film tends to decrease. When it exceeds 12 cm ³ / g, it tends to be difficult to obtain.
The apparent specific volume of the amorphous inorganic powder (A2) is measured according to JIS K5101-12-1: 2004. The larger the apparent specific volume value, the more bulky.

As a commercial product of amorphous inorganic powder (A2), amorphous silica (trade name Fine Seal X-60, manufactured by Tokuyama Corporation, average particle diameter 6 μm, apparent specific volume 4.7 cm ³ / g) Amorphous aluminum hydroxide (trade name KYOWARD 200S, manufactured by Kyowa Chemical Industry Co., Ltd., average particle size 30 μm, apparent specific volume 3.7 cm ³ / g), amorphous aluminum silicate (trade name KYOWARD 700SL) , Manufactured by Kyowa Chemical Industry Co., Ltd., average particle size 65 μm, apparent specific volume 3.0 cm ³ / g), hydrotalcite (trade name Kyoward 500PL, manufactured by Kyowa Chemical Industry Co., Ltd., average particle size 10 μm, apparent ratio volume 5.2 cm ³ / g), magnesium silicate (trade name Kyoward 600, manufactured by Kyowa chemical industry Co., Ltd., average particle size 10 [mu] m, apparent specific volume 4.8 cm ³ / g), silicic acid Calcium (trade name FLORITE R, (Ltd.) manufactured by Tokuyama, average particle size 8 [mu] m, apparent specific volume 10 cm ³ / g), magnesium carbonate (trade name magnesium carbonate TT, (Ltd.) manufactured by Tokuyama, average particle size 10 [mu] m, apparent specific Volume 4.5 cm ³ / g) and the like.
One kind of amorphous inorganic powder (A2) may be used alone, or two or more kinds may be used in combination.

(Binder (B))
The binder (B) carries the hydrophilic fumed silica (A1) and / or amorphous inorganic powder (A2) on the surface of the base material, or is hydrophilic on the surface of the amorphous inorganic powder (A2). For supporting fumed silica (A1).

  The binder (B) is composed of at least one selected from the group consisting of a resin (B1) and an alkoxysilane compound or a partially hydrolyzed condensate (B2) thereof. From the viewpoint of obtaining a coating film having good durability as the binder (B), it is preferable to use the resin (B1) and an alkoxysilane compound or a partial hydrolysis-condensation product (B2) in combination.

When the resin (B1) and the alkoxysilane compound or its partial hydrolysis condensate (B2) are used in combination as the binder (B), the hydrophilicity and durability of the resulting coating film are further improved. As the composition, the following composition (α) or composition (β) is preferable, and the composition (α) is more preferable.
(Α) Hydrophilic fumed silica (A1), resin (B1), and alkoxysilane compound or partially hydrolyzed condensate (B2) thereof are mixed, and hydrophilic fumed silica (A1) and alkoxysilane compound or A composition obtained by mixing the partially hydrolyzed condensate (B2) with an amorphous inorganic powder (A2).
(Β) Hydrophilic fumed silica (A1), an alkoxysilane compound or a partially hydrolyzed condensate thereof (B2) mixed and reacted, resin (B1), and amorphous inorganic powder A composition obtained by mixing the body (A2).

In addition to the alkoxysilane compound or its partially hydrolyzed condensate (B2), a trialkoxysilane compound or its partially hydrolyzed condensate may be used as the binder (B) for the purpose of improving the durability of the coating film. I do not care.
The binder (B) may contain additional components such as a curing agent and a catalyst as necessary.

(Resin (B1))
The resin (B1) is not particularly limited as long as it can be solidified or cured by heat, ultraviolet rays, a catalyst or the like to form a coating film. For example, acrylic resin, urethane resin, silicone resin, epoxy resin , Vinyl acetate resin, melamine resin, polyvinyl alcohol, and the like, and urethane resin, acrylic resin, and polyvinyl alcohol are preferable from the viewpoint of hardly causing hydrophilic inhibition of the resulting coating film.

As commercial products of resin (B1), Evaphanol HA-50C (polyurethane resin, manufactured by Nikka Chemical Co., Ltd., non-volatile content 35% by mass), mobile 6520 (acrylic resin, manufactured by Nippon Synthetic Chemical Co., Ltd., non-volatile content 46) Mass%), PVA-117 (polyvinyl alcohol, manufactured by Kuraray Co., Ltd.) and the like.
The non-volatile content means a component that remains in the coating film without being volatilized even after film formation, and the non-volatile content of the binder (B) is usually a binder component and a curing agent or catalyst added as necessary. And the like.
Resin (B1) may be used individually by 1 type, and may be used in combination of 2 or more type.

The resin (B1) may be mixed with other components only in a solid content (nonvolatile content), or may be mixed with other components in a solution containing a medium or an emulsified dispersion.
Examples of the medium include water and organic solvents.

  Examples of the organic solvent include aliphatic alcohols having 1 to 8 carbon atoms (methanol, ethanol, isopropyl alcohol, isobutyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, etc.), hydrocarbons (n-hexane, isohexane, cyclohexane, methylcyclohexane). , N-heptane, isooctane, n-decane, mineral terpene, turpentine oil, isoparaffin, toluene, xylene, solvent naphtha, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, diacetone alcohol, etc.), Esters (ethyl acetate, methyl acetate, butyl acetate, methyl lactate, ethyl lactate, etc.), ethers (diethyl ether, diisopropyl ether, methyl cellosolve, ethyl acetate) Solve, butyl cellosolve, dioxane, methyl tertiary butyl ether, butyl carbitol, etc.), glycols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, etc.), glycol ethers (diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, propylene glycol) Monomethyl ether, 3-methoxy-3-methyl-1-butanol, etc.) and glycol esters (ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, etc.).

(Alkoxysilane compound or its partial hydrolysis condensate (B2))
The alkoxysilane compound or its partially hydrolyzed condensate (B2) also functions as a silane coupling agent.

  The alkoxysilane compound or its partial hydrolysis condensate (B2) is selected from the group consisting of a dialkoxysilane compound or its partial hydrolysis condensate (B21) and a tetraalkoxysilane compound or its partial hydrolysis condensate (B22). It consists of at least one kind.

  Since the dialkoxysilane compound has two alkoxy groups which are hydrolyzable groups, it is considered that a linear (two-dimensional structure) bond can be formed with various compounds. Alternatively, it is considered that a polysiloxane bonded linearly can be formed by a condensation reaction between dialkoxysilane compounds. Therefore, it is considered that a coating film having hydrophilicity and durability can be obtained.

  Tetraalkoxysilane compounds form complex three-dimensional structures with various compounds, or tetraalkoxysilane compounds form complex three-dimensional structures, improving the durability of coating films and inhibiting hydrophilicity. However, since it contains four hydrophilic siloxy groups, it is considered that there is little inhibition of hydrophilicity.

  The trialkoxysilane compound is considered to form a complex three-dimensional structure with various compounds as in the case of the tetraalkoxysilane compound, or between the trialkoxysilane compounds to form a complex three-dimensional structure. Further, since there are three siloxy groups that are hydrophilic, it is considered that hydrophilic inhibition occurs. Moreover, when the residue of a trialkoxysilane compound is a hydrophobic group, it is considered that the hydrophobic group is exposed on the surface and inhibits the hydrophilicity of the coating film. Even when the residue is a hydrophilic group, it is considered that the hydrophilicity of the coating film is not improved because not all the hydrophilic groups are oriented on the surface.

  For the reasons described above, when the dialkoxysilane compound and / or tetraalkoxysilane compound is compared with the trialkoxysilane compound, it is considered that the hydrophilicity and durability of the resulting coating film are different.

Before preparing the coating composition, the dialkoxysilane compound and / or the tetraalkoxysilane compound may be partially hydrolyzed and partially condensed by adding water and a catalyst in advance to form a partially hydrolyzed condensate. In preparing the product, it may be partially hydrolyzed and partially condensed by adding water and a catalyst to the mixture of each component, and may be partially hydrolyzed condensate in the composition.
A known catalyst may be used as the catalyst.

(Dialkoxysilane compound or partially hydrolyzed condensate thereof (B21))
The dialkoxysilane compound or a partially hydrolyzed condensate thereof (B21) is a dialkoxysilane compound represented by the following formula (1) or a partially hydrolyzed condensate thereof.
Si (R ¹ ) (R ² ) (OR ³ ) (OR ⁴ ) (1)
(In the formula (1), R ¹ and R ² are each an alkyl group having 1 to 6 carbon atoms, an aminoalkyl group having 1 to 8 carbon atoms, or a glycidoxyalkyl group, and R ³ and R ⁴ are respectively (It is an alkyl group having 1 to 6 carbon atoms.)

Examples of the alkyl group having 1 to 6 carbon atoms of R ¹ and R ² include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-pentyl group, isopentyl group, and n-hexyl. Group, isohexyl group and the like.
Examples of the aminoalkyl group having 1 to 8 carbon atoms include N-2- (aminoethyl) -3-aminopropyl group and 3-aminopropyl group.
Examples of the glycidoxyalkyl group having 1 to 8 carbon atoms include glycidoxymethyl group, glycidoxyethyl group, 3-glycidoxypropyl group, 4-glycidoxybutyl group, and 5-glycidoxypentyl group. , 6-glycidoxyhexyl group, 7-glycidoxyheptyl group, 8-glycidoxyoctyl group and the like.
R ¹ and R ² are preferably a methyl group, an N-2- (aminoethyl) -3-aminopropyl group, or a 3-glycidoxypropyl group from the viewpoint of the hydrophilicity of the resulting coating film, and R ¹ , More preferably, at least one of R ² is a glycidoxyalkyl group.

Examples of the alkyl group having 1 to 6 carbon atoms of R ³ and R ⁴ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-pentyl group, isopentyl group, and n-hexyl. Group, isohexyl group, and the like. From the viewpoint of reactivity and ease of use, a methyl group and an ethyl group are preferable, and an ethyl group is more preferable.

Commercially available dialkoxysilane compounds include 3-glycidoxypropylmethyldimethoxysilane (trade name, KBM-402, manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropylmethyldiethoxysilane (trade name, KBE-402, manufactured by Shin-Etsu Chemical Co., Ltd.), N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane (trade name, KBM-602, manufactured by Shin-Etsu Chemical Co., Ltd.), and the like.
A dialkoxysilane compound may be used individually by 1 type, and may be used in combination of 2 or more type. However, it is not preferable to use a dialkoxysilane compound having a glycidoxyalkyl group and a dialkoxysilane compound having an amino group in combination.

  When the dialkoxysilane compound has a glycidoxyalkyl group, the reaction is preferably carried out under an acidic condition using an acidic catalyst as a reaction catalyst.

  The acidic catalyst is not particularly limited, and examples thereof include organic acids (acetic acid, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid. , Toluenesulfonic acid, oxalic acid, etc.), inorganic acids (hydrochloric acid, nitric acid, phosphoric acid, halogenated silane, etc.), acidic sol fillers (acidic colloidal silica, titania sol, etc.) and the like. An acidic catalyst may be used individually by 1 type, and may be used in combination of 2 or more type.

  Under acidic condition, the pH is less than 7, preferably 1 to 4, and more preferably 1 to 3. When the pH is 7 or more, the durability of the resulting coating film tends to be inferior. After the reaction, it may remain in an acidic state or may be in a state adjusted to an arbitrary pH.

  When the dialkoxysilane compound has an aminoalkyl group, the reaction is preferably performed under alkalinity. The dialkoxysilane compound having an aminoalkyl group alone exhibits alkalinity, but may be rendered alkaline by using an alkaline catalyst as a reaction catalyst.

  Although it does not specifically limit as an alkali catalyst, For example, hydroxide (sodium hydroxide, potassium hydroxide, ammonium hydroxide, etc.), carbonates (sodium carbonate, potassium carbonate, ammonium carbonate, etc.), hydrogen carbonate Salt (sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, etc.), aliphatic amines (methylamine, ethylamine, butylamine, dimethylamine, diethylamine, dibutylamine, trimethylamine, triethylamine, tributylamine, etc.), aliphatic polyamines ( Ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, etc.), aromatic amines (aniline, methylaniline, ethylaniline, methylbenzylamine, etc.), amino alcohols (monoethanolamine, Ethanolamine, triethanolamine, etc.), heterocyclic amines (pyridine, morpholine, pyrrolidine, piperidine, etc.), tin compounds (dibutyltin dilaurate, etc.), zinc compounds (zinc stearate, etc.), aluminum-based metal catalysts, titanium-based A metal catalyst etc. are mentioned. An alkali catalyst may be used individually by 1 type, and may be used in combination of 2 or more type.

  Under alkaline is a case where the pH exceeds 7, preferably 10 to 12. When the pH is 7 or less, the durability of the resulting coating film tends to be inferior. After the reaction, it may remain in an alkaline state or may be in a state adjusted to an arbitrary pH.

(Tetraalkoxysilane compound or partially hydrolyzed condensate thereof (B22))
The tetraalkoxysilane compound or its partial hydrolysis condensate (B22) is a tetraalkoxysilane compound represented by the following formula (2) or its partial hydrolysis condensate.
Si (OR ⁵ ) (OR ⁶ ) (OR ⁷ ) (OR ⁸ ) (2)
(In Formula (2), R < ⁵ > -R < ⁸ > is a C1-C6 alkyl group, respectively.)

Examples of the alkyl group having 1 to 6 carbon atoms of R ^{5 to} R ⁸ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-pentyl group, isopentyl group, and n-hexyl. Group, isohexyl group, and the like. From the viewpoint of reactivity and ease of use, a methyl group and an ethyl group are preferable, and an ethyl group is more preferable.

Examples of commercially available tetraalkoxysilane compounds include tetraethoxysilane (trade name, KBE-04, manufactured by Shin-Etsu Chemical Co., Ltd.).
A tetraalkoxysilane compound may be used individually by 1 type, and may be used in combination of 2 or more type.

(Dilution medium)
In the coating composition of the present invention, in order to make the non-volatile content of the hydrophilic fumed silica (A1), the amorphous inorganic powder (A2), and the binder (B) suitable for application, Dilution media may be added.
Although it does not specifically limit as a dilution medium, A substantially inert thing is preferable and water and an organic solvent are mentioned.

  Examples of the organic solvent include aliphatic alcohols having 1 to 8 carbon atoms (methanol, ethanol, isopropyl alcohol, isobutyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, etc.), hydrocarbons (n-hexane, isohexane, cyclohexane, methylcyclohexane). , N-heptane, isooctane, n-decane, mineral terpene, turpentine oil, isoparaffin, toluene, xylene, solvent naphtha, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, diacetone alcohol, etc.), Esters (ethyl acetate, methyl acetate, butyl acetate, methyl lactate, ethyl lactate, etc.), ethers (diethyl ether, diisopropyl ether, methyl cellosolve, ethyl acetate) Solve, butyl cellosolve, dioxane, methyl tertiary butyl ether, butyl carbitol, etc.), glycols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, etc.), glycol ethers (diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, propylene glycol) Monomethyl ether, 3-methoxy-3-methyl-1-butanol, etc.) and glycol esters (ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, etc.). An organic solvent may be used individually by 1 type, and 2 or more types may be mixed and used as a mixed solvent. Moreover, the acid, alkali, etc. as a pH adjuster may further be included.

(Thickener)
In the coating composition of the present invention, in order to maintain the dispersibility of the hydrophilic fumed silica (A1), the amorphous inorganic powder (A2), and the binder (B) and improve the workability of coating, A thickener may be used.
The thickening agent is not particularly limited. , Casein, gelatin, collagen, etc.), cellulose derivatives (carboxymethyl cellulose (CMC), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), crystalline cellulose, etc.), starch and its derivatives (various starches, carboxymethyl starch) (CMS), hydroxyethyl starch, etc.), synthetic polymers (polyvinyl alcohol (PVA), sodium polyacrylate, polymaleic acid, polyethylene oxide, polyacrylic acid) Ruamido, polydiallylamine, etc.) and the like. A thickener may be used individually by 1 type, and may be used in combination of 2 or more type.

(Other additives)
The coating composition of the present invention includes a surface tension adjusting agent, a surfactant, a leveling agent, a thixotropic agent, an antifoaming agent, a freezing stabilizer, a matting agent, a pigment, a dye, a dispersant, a wetting agent, and a light stabilizer. Antioxidants, UV absorbers, rheology control agents, film-forming aids, rust inhibitors, dyes, antiseptics, antifungal agents, deodorants, anti-yellowing agents, antistatic agents, charge control agents, etc. , May be appropriately selected according to use, usage method, etc., and may be added in combination as necessary.
You may express a photocatalytic action by adding the optical semiconductor represented by the titanium oxide to the coating composition of this invention.

(composition)
The mass ratio between the hydrophilic fumed silica (A1) and the amorphous inorganic powder (A2) is (A1) :( A2) = 10: 90 from the viewpoint of the hydrophilicity and durability of the resulting coating film. -80: 20 is preferable, 20: 80-70: 30 is more preferable, and 30: 70-60: 40 is more preferable.

  The mass ratio between the total of the hydrophilic fumed silica (A1) and the amorphous inorganic powder (A2) and the nonvolatile content of the binder (B) is determined from the viewpoint of the hydrophilicity and durability of the resulting coating film [ (A1) + (A2)] :( B) = 20: 80 to 90:10 is preferable, and 40:60 to 80:20 is more preferable.

  When using an alkoxysilane compound or its partially hydrolyzed condensate (B2), the mass ratio of the hydrophilic fumed silica (A1) and the non-volatile content of the alkoxysilane or its partially hydrolyzed condensate (B2) is the coating obtained From the viewpoint of the hydrophilicity and durability of the membrane, (A1) :( B2) = 90: 10 to 20:80 is preferable, and 85:15 to 35:65 is more preferable.

  The mass ratio of the total of the hydrophilic fumed silica (A1) and the amorphous inorganic powder (A2) to the non-volatile content of the alkoxysilane compound or its partially hydrolyzed condensate (B2) is determined by the hydrophilicity of the resulting coating film. From the viewpoints of durability and durability, [(A1) + (A2)] :( B2) = 20: 80 to 90:10 is preferable, and 40:60 to 80:20 is more preferable.

  The mass ratio between the nonvolatile content of the resin (B1) and the nonvolatile content of the alkoxysilane compound or its partial hydrolysis-condensation product (B2) is (B1) :( B2) = 95 from the viewpoint of the durability of the resulting coating film. : 5-5: 95 is preferable, and 75: 25-25: 75 is more preferable.

When the trialkoxysilane compound or its partial hydrolysis condensate is used in combination, the proportion of the nonvolatile content of the trialkoxysilane compound or its partial hydrolysis condensate is the non-volatile content of the alkoxysilane compound or its partial hydrolysis condensate (B2). The amount is preferably 10 parts by mass or less with respect to 100 parts by mass, and most preferably not contained at all.
When the binder (B) contains additional components such as a curing agent and a catalyst, the proportion of the additional components is preferably 10 parts by mass or less with respect to 100 parts by mass of the binder component.

(Manufacturing method of coating composition)
The coating composition of the present invention comprises hydrophilic fumed silica (A1); amorphous inorganic powder (A2); resin (B1), dialkoxysilane compound or partially hydrolyzed condensate thereof (B21), And a binder (B) composed of at least one selected from the group consisting of a tetraalkoxysilane compound or a partially hydrolyzed condensate (B22) thereof.

  When the coating composition of the present invention is the composition (α) described above, hydrophilic fumed silica (A1) and an alkoxysilane compound or a partially hydrolyzed condensate thereof (B2) in the presence of the resin (B1). Can be made to react with each other and mixed with amorphous inorganic powder (A2).

  When the coating composition of the present invention is the above-described composition (β), the hydrophilic fumed silica (A1) is reacted with the alkoxysilane compound or the partially hydrolyzed condensate (B2) thereof, and then amorphous. Quality inorganic powder (A2) and resin (B1) can be mixed.

Specifically, the coating composition of the present invention can be produced, for example, by the following methods (X) to (Z).
Method (X):
After preliminarily mixing the hydrophilic fumed silica (A1), the organic solvent, and water, a dispersion treatment is performed at 5 to 100 ° C. and 5 to 200 MPa using an emulsifier. Thereafter, the amorphous inorganic powder (A2), the binder (B) and optionally a thickener are added, and the mixture is stirred and mixed uniformly at 10 to 100 ° C. to obtain the coating composition of the present invention.

Method (Y):
After preliminarily mixing the hydrophilic fumed silica (A1), the organic solvent, and water, a dispersion treatment is performed at 5 to 100 ° C. and 5 to 200 MPa using an emulsifier. Thereafter, the resin (B1), the alkoxysilane compound or its partially hydrolyzed condensate (B2) and optionally a catalyst are added, adjusted to a predetermined pH, and reacted at 10 to 100 ° C. for 10 minutes to 1 day. In the presence of the resin (B1), a reaction product is obtained by reacting the hydrophilic fumed silica (A1) with the alkoxysilane compound or its partial hydrolysis condensate (B2). Thereafter, the amorphous inorganic powder (A2) and, if necessary, a thickener are added, and the mixture is uniformly stirred and mixed with a homomixer or the like at 10 to 100 ° C. to obtain the coating composition of the present invention. .

Method (Z):
After preliminarily mixing the hydrophilic fumed silica (A1), the organic solvent, and water, a dispersion treatment is performed at 5 to 100 ° C. and 5 to 200 MPa using an emulsifier. Thereafter, an alkoxysilane compound or a partially hydrolyzed condensate thereof (B2) and, if necessary, a catalyst are added, adjusted to a predetermined pH, and reacted at 10 to 100 ° C. for 10 minutes to 1 day. A reaction product of silica (A1) and an alkoxysilane compound or a partial hydrolysis-condensation product (B2) thereof is obtained. Thereafter, the amorphous inorganic powder (A2), the resin (B1), and, in some cases, a thickener are added, and the mixture is stirred and mixed uniformly at 10 to 100 ° C. with a homomixer or the like. A coating composition is obtained.

  Examples of the emulsifier that can be used to perform the dispersion treatment of the hydrophilic fumed silica (A1) include, for example, a homogenizer (manufactured by NIRO SOAVI or APV GAULIN), a homomixer (manufactured by PRIMIX Corporation), and a nanomizer. (Yoshida Kikai Kogyo Co., Ltd.), Ultimizer (Sugino Machine Co., Ltd.), Starburst (Sugino Machine Co., Ltd.), Ultrasonic Disperser (Nihon Seiki Seisakusho Co., Ltd.), and the like. An emulsifier may be used individually by 1 type and may be used in combination of 2 or more type.

(Function and effect)
In the coating composition of the present invention described above, hydrophilic fumed silica (A1) having a small particle size in a specific range; and an amorphous inorganic material having a large particle size in a specific range and an apparent specific volume in a specific range. Since it is formed by mixing the powder (A2) and the binder (B), it has super hydrophilicity with a water contact angle of 5 ° or less immediately after the film formation even in an environment without light. It is possible to easily and efficiently form a coating film having excellent durability.
The reason why a super hydrophilic coating film having excellent durability can be formed by the coating composition of the present invention is considered as follows.

  By using two or more kinds of particles with high hydrophilicity, different particle size, and very high bulkiness, it is considered that super hydrophilicity is exhibited by the effect of surface roughness (synergistic effect of unevenness). It is done. Further, by adhering the small particle size hydrophilic fumed silica (A1) to the concave portion of the large particle size amorphous inorganic powder (A2), and further using the binder (B) in combination with them, It is thought that durability can be improved.

  When the resin (B1) and the alkoxysilane compound or its partial hydrolysis condensate (B2) are used in combination as the binder (B), in addition to the formation of a hydrolysis condensate of the alkoxysilane compound, hydrophilic fume Since a composite of desilica (A1), amorphous inorganic powder (A2), resin (B1), alkoxysilane compound and / or hydrolysis condensate of alkoxysilane compound is formed, the hydrophilicity of the coating film It is considered that the durability is improved while maintaining the above.

  Furthermore, by reacting the hydrophilic fumed silica (A1) with the alkoxysilane compound or its partial hydrolysis condensate (B2) in advance, the particles of the structurally brittle hydrophilic fumed silica (A1) are bonded together. It is possible to form a composite that is effectively tied together, and the durability can be improved while maintaining high bulkiness and hydrophilicity. By using this composite, the resin (B1) and the amorphous inorganic powder (A2) in combination, the hydrophilic fumed silica (A1) is efficiently attached to the amorphous inorganic powder (A2). It is considered that good superhydrophilicity and durability can be obtained.

  Further, when the hydrophilic fumed silica (A1) and the alkoxysilane compound or the partial hydrolysis condensate (B2) thereof are reacted in advance, the presence of the resin (B1) allows the hydrophilic fumed silica ( A composite of A1), resin (B1), alkoxysilane compound and / or hydrolysis condensate of alkoxysilane compound is formed. This composite has both good hydrophilicity and durability, and by using this composite in combination with the amorphous inorganic powder (A2), an amorphous inorganic powder can be efficiently and reliably obtained. Since a composite (including hydrophilic fumed silica (A1)) can be attached to the surface of (A2), it is considered that very good superhydrophilicity and durability can be obtained.

<Article with coating film>
The article with a coating film of the present invention has a coating film made of the coating composition of the present invention on the surface of a substrate.

(Base material)
The substrate is not particularly limited, and examples thereof include substrates made of various materials such as glass, metal, paper, ceramics, cement material, synthetic resin, fiber, and painted surface.
By using the coating composition of the present invention, a coating film can be easily and efficiently formed without performing a special operation on various substrates.

(Coating film)
The film thickness of the coating film is not particularly limited, and may be, for example, about 0.5 μm to 1 mm. The coating film is stably adhered and held on the surface of the substrate over a long period of time, and cracks and From the viewpoint of preventing peeling, 10 to 500 μm is preferable.

(Method for producing article with coating film)
The article with a coating film of the present invention can be produced by applying the coating composition of the present invention to at least a part of the surface of a substrate and then drying.

  The coating method is not particularly limited, and any method can be adopted. For example, brush coating, spray coating, dipping (dip coating), roll coating, curtain coating, spin coating, bar coating, flow coating, etc. The usual method is mentioned.

  The drying method is not particularly limited, and in the present invention, it is possible to dry without heating. In the conventional method for forming a coating film, heating is usually required. However, when forming a coating film in the present invention, the same function can be exhibited by drying at room temperature. In the present invention, a method of heating and drying may be employed for the purpose of promoting film formation. In that case, the time for film formation can be further shortened. The film-forming temperature is suitably 10 to 150 ° C., but may be appropriately adjusted depending on the substrate used.

  In order to give excellent friction resistance to the coating film, it is preferable to apply the coating composition of the present invention after cleaning the surface of the substrate. That is, it is preferable to substantially remove organic contaminants from the surface of the substrate prior to application. Although the cleaning process varies depending on the material of the base material, for example, a cleaning process using an organic solvent (acetone, ethanol, etc.) is effective.

(Function and effect)
In the article with a coating film of the present invention described above, it has a superhydrophilic property with a water contact angle of 5 ° or less and has a coating film with excellent durability on its surface, so that it can be sustained outdoors. Even in an environment exposed to rainwater (running water), the antifouling effect due to self-cleaning ability (self-cleaning) can be demonstrated for a long time.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, these do not limit the scope of the present invention.

<Measurement / Evaluation>
(Measurement of contact angle)
Using a portable contact angle meter (manufactured by Matsubo Co., Ltd., PG-X), the static contact angle of water on the surface of the coating film of the article with the coating film was measured at 20 ° C. The amount of distilled water dropped was 2.5 μL, and the static contact angle of water was measured 30 seconds after dropping distilled water.

(Measurement of water film spread width)
Distilled water 10 μL was gently spotted on the surface of the coating film of the article with the coating film placed horizontally, and the width of the water film after 30 seconds was measured with a ruler. It is determined that the larger the spread width, the greater the hydrophilicity.

(Evaluation of wear resistance)
The article with the coating film was placed on an electronic balance and rubbed with a finger three times so that a load of about 300 g was applied. Observe the powder on the finger after rubbing. “○” indicates no powder, “△” indicates that some powder is observed, and “×” indicates that a significant powder is observed. It was evaluated.

(Running water test method)
The article with the coating film was fixed along the inner surface of the cylindrical stainless steel pot, and tap water was added until all the articles with the coating film were immersed. Water in the pot was stirred at 150 rpm at 25 ° C. for 74 hours with a fan turbine type stirring blade attached to a stirrer. After stirring for a predetermined time, the article with the coating film was dried at 105 ° C. for 30 minutes, and then the contact angle and the water film spread width were measured. The tap water stirred for 74 hours was replaced with fresh tap water about every 8 hours.

<Each component>
(Hydrophilic fumed silica (A1))
Hydrophilic fumed silica (A1-1): trade name AEROSIL 300CF (manufactured by Nippon Aerosil Co., Ltd., average particle size 7 nm).
Hydrophilic fumed silica (A1-2): trade name AEROSIL 130 (manufactured by Nippon Aerosil Co., Ltd., average particle size 16 nm).
Hydrophilic fumed silica (A1-3): trade name AEROSIL OX50 (manufactured by Nippon Aerosil Co., Ltd., average particle size 40 nm).

(Amorphous inorganic powder (A2))
Amorphous inorganic powder (A2-1): trade name Fine Seal X-60 (amorphous silica, manufactured by Tokuyama Corporation, average particle size 6 μm, apparent specific volume 4.7 cm ³ / g).
Amorphous inorganic powder (A2-1 ′): Fine seal X-60 (300 parts by mass) having a solid content of 50% by mass, 0.5 mm beads (150 parts by mass), a sand grinder (Igarashi Machinery Manufacturing Co., Ltd.) And made finer at 1200 rpm (average particle size 0.2 μm).
Amorphous inorganic powder (A2-2): trade name KYOWARD 700PEL (amorphous aluminum silicate, manufactured by Kyowa Chemical Industry Co., Ltd., average particle size 2 μm, apparent specific volume 8.8 cm ³ / g).
Amorphous inorganic powder (A2-3): trade name KYOWARD 700SN (amorphous aluminum silicate, manufactured by Kyowa Chemical Industry Co., Ltd., average particle size 200 μm, apparent specific volume 2.6 cm ³ / g).
Amorphous inorganic powder (A2-4): trade name Shuklens KD-211G (silica / zinc oxide composite, manufactured by Lhasa Kogyo Co., Ltd., average particle size 3 μm, apparent specific volume 2.5 cm ³ / g).
Amorphous inorganic powder (A2-5): trade name Fine Seal T-32 (silica, manufactured by Tokuyama Corporation, average particle size 1.5 μm, apparent specific volume 10 cm ³ / g).
Amorphous inorganic powder (A2-6): trade name KYOWARD 500PL (Hydrotalcite, manufactured by Kyowa Chemical Industry Co., Ltd., average particle size 10 μm, apparent specific volume 5.2 cm ³ / g).
Amorphous inorganic powder (A2-7): trade name KYOWARD 600 (magnesium silicate, manufactured by Kyowa Chemical Industry Co., Ltd., average particle size 10 μm, apparent specific volume 4.8 cm ³ / g).
Amorphous inorganic powder (A2-8): trade name KYOWARD 200S (amorphous aluminum hydroxide, manufactured by Kyowa Chemical Industry Co., Ltd., average particle size 30 μm, apparent specific volume 3.7 cm ³ / g).
Amorphous inorganic powder (A2-9): trade name FLORITE R (calcium silicate, manufactured by Tokuyama Corporation, average particle diameter 8 μm, apparent specific volume 10 cm ³ / g).
Amorphous inorganic powder (A2-10): trade name KYOWARD 700SL (amorphous aluminum silicate, manufactured by Kyowa Chemical Industry Co., Ltd., average particle diameter 65 μm, apparent specific volume 3.0 cm ³ / g).

(Resin (B1))
Resin (B1-1): 10 mass% aqueous solution of brand name PVA-117 (polyvinyl alcohol, Kuraray Co., Ltd.).
Resin (B1-2): Trade name Evaphanol HA-50C (polyurethane resin, manufactured by Nikka Chemical Co., Ltd., nonvolatile content 35% by mass).
Resin (B1-3): Trade name Mobile 6520 (acrylic resin, manufactured by Nippon Synthetic Chemical Co., Ltd., nonvolatile content: 46% by mass).

(Alkoxysilane compound or its partial hydrolysis condensate (B2))
Dialkoxysilane compound (B21-1): trade name KBE-402 (3-glycidoxypropylmethyldiethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.).
Dialkoxysilane compound (B21-2): trade name KBM-602 (N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.).
Tetraalkoxysilane compound (B22-1): trade name KBE-04 (tetraethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.)
Trialkoxysilane compound (B23-1): Trade name KBE-403 (3-glycidoxypropyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.)
Trialkoxysilane compound (B23-2): Trade name KBE-603 (N-2- (aminoethyl) -3-aminopropyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.)

(Other)
Product name Snowtex OXS (colloidal silica, manufactured by Nissan Chemical Industries, Ltd., average particle size 5 nm, silica content 10 mass%).
Product name Galeon Earth V1 (active whiteness, manufactured by Mizusawa Chemical Co., Ltd., particle size of 90 μm or less is 95%, apparent specific volume is 1.4 cm ³ / g).
Product name Snowtex N (ammonia neutralized water-dispersible silica sol, manufactured by Nissan Chemical Industries, Ltd., average particle size of 10 to 20 nm, silica content of 20% by mass).
Product name Rikasurf P-10 (di (2-ethylhexyl) sulfosuccinate sodium, manufactured by Shin Nippon Rika Co., Ltd., active ingredient 70%).
Product name ST-O (silica sol, manufactured by Nissan Chemical Industries, Ltd., average particle size 10 to 20 nm, silica content 20% by mass).
Product name ST-OL (silica sol, manufactured by Nissan Chemical Industries, Ltd., average particle size 40-50 nm, silica content 20% by mass).
Product name BYK-346 (polyether-modified polydimethylsiloxane, manufactured by Degussa, non-volatile content: 45% by mass).

[Example 1]
2 parts by mass of hydrophilic fumed silica (A1-1), 10 parts by mass of isopropyl alcohol, and 65.5 parts by mass of ion-exchanged water were mixed and premixed, and then dispersed by a homogenizer device (30 MPa, 25 ° C.). Treated.
Thereafter, 2 parts by mass of amorphous inorganic powder (A2-1), 20 parts by mass of resin (B1-1) (2 parts by mass in terms of nonvolatile content), and JAGUAR HP-105 (Rhodia as a thickener) 0.5 parts by mass) was added and uniformly stirred and mixed with a homomixer to obtain a white liquid coating composition having a nonvolatile content of 6.5% by mass.

On the surface of an iron test piece (7 cm × 6 cm, water contact angle 70 °) that was acrylic-coated with an aqueous multipurpose spray (made by Asahi Pen Co., Ltd., white), an auto film An article with a coating film was obtained by applying with an applicator (product name PI-1210, manufactured by Tester Sangyo Co., Ltd.) and drying at 105 ° C. for 60 minutes.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 1.

[Examples 2-15, 19-35, Comparative Examples 1-5, 8]
Except having changed into the composition shown in Tables 1-6, 11, and 12, the same operation as in Example 1 was performed to obtain articles with coating films of Examples 2 to 15, 19 to 35, and Comparative Examples 1 to 5 and 8. It was.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Tables 1-6, 11, and 12.

Example 16
2 parts by mass of hydrophilic fumed silica (A1-1), 10 parts by mass of isopropyl alcohol, and 61.5 parts by mass of ion-exchanged water were mixed and premixed, and then dispersed by a homogenizer device (30 MPa, 25 ° C.). Treated.
Thereafter, 2 parts by mass of amorphous inorganic powder (A2-1) and 2 parts by mass of dialkoxysilane compound (B21-1) were added and adjusted to pH 2 with nitric acid as an acidic catalyst, and then at 50 ° C. The reaction was allowed for 5 hours.
Thereafter, the pH is adjusted to 6 to 8 with sodium hydroxide, 0.5 part by mass of JAGUAR HP-105 (manufactured by Rhodia) is added as a thickener, and the mixture is stirred and mixed uniformly with a homomixer. A white liquid coating composition was obtained at a content of 6.5% by mass.

On the surface of an iron test piece (7 cm × 6 cm, water contact angle 70 °) that was acrylic-coated with an aqueous multipurpose spray (made by Asahi Pen Co., Ltd., white), an auto film An article with a coating film was obtained by applying with an applicator (product name PI-1210, manufactured by Tester Sangyo Co., Ltd.) and drying at 105 ° C. for 60 minutes.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 3.

Example 17
A dialkoxysilane compound (B21-2) is used in place of the dialkoxysilane compound (B21-1), the reaction is performed at pH 11 without adding an alkali catalyst, and the pH is adjusted to 6 to 8 with nitric acid after the reaction. Were operated in the same manner as in Example 16 to obtain an article with a coating film of Example 17.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 3.

Example 18
An article with a coating film of Example 18 was obtained in the same manner as in Example 16 except that the tetraalkoxysilane compound (B22-1) was used instead of the dialkoxysilane compound (B21-1).
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 3.

Example 36
2 parts by mass of hydrophilic fumed silica (A1-1), 10 parts by mass of isopropyl alcohol, and 61.5 parts by mass of ion-exchanged water were mixed and premixed, and then dispersed by a homogenizer device (30 MPa, 25 ° C.). Treated.
Then, 2 parts by mass of the amorphous inorganic powder (A2-1), 10 parts by mass of the resin (B1-1), and 1 part by mass of the dialkoxysilane compound (B21-1) are added to form an acidic catalyst. After adjusting to pH 2 with nitric acid, the mixture was reacted at 50 ° C. for 5 hours.
Thereafter, the pH is adjusted to 6 to 8 with sodium hydroxide, 0.5 part by mass of JAGUAR HP-105 (manufactured by Rhodia) is added as a thickener, and the mixture is stirred and mixed uniformly with a homomixer. A white liquid coating composition was obtained at a content of 6.5% by mass.

On the surface of an iron test piece (7 cm × 6 cm, water contact angle 70 °) that was acrylic-coated with an aqueous multipurpose spray (made by Asahi Pen Co., Ltd., white), an auto film An article with a coating film was obtained by applying with an applicator (product name PI-1210, manufactured by Tester Sangyo Co., Ltd.) and drying at 105 ° C. for 60 minutes.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 6.

Example 37
2 parts by mass of hydrophilic fumed silica (A1-1), 10 parts by mass of isopropyl alcohol, and 61.5 parts by mass of ion-exchanged water were mixed and premixed, and then dispersed by a homogenizer device (300 MPa, 25 ° C.). Treated.
Thereafter, 1 part by mass of dialkoxysilane compound (B21-1) was added and adjusted to pH 2 with nitric acid as an acidic catalyst, and then reacted at 50 ° C. for 5 hours.
Thereafter, the pH is adjusted to 6-8 with sodium hydroxide, 2 parts by mass of amorphous inorganic powder (A2-1), 10 parts by mass of resin (B1-1), and JAGUAR HP as a thickener. 0.5 part by mass of -105 (manufactured by Rhodia) was added and stirred and mixed uniformly with a homomixer to obtain a white liquid coating composition having a nonvolatile content of 6.5% by mass.

On the surface of an iron test piece (7 cm × 6 cm, water contact angle 70 °) that was acrylic-coated with an aqueous multipurpose spray (made by Asahi Pen Co., Ltd., white), an auto film An article with a coating film was obtained by applying with an applicator (product name PI-1210, manufactured by Tester Sangyo Co., Ltd.) and drying at 105 ° C. for 60 minutes.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 7.

Example 38
2 parts by mass of hydrophilic fumed silica (A1-1), 10 parts by mass of isopropyl alcohol, and 61.5 parts by mass of ion-exchanged water were mixed and premixed, and then dispersed by a homogenizer device (300 MPa, 25 ° C.). Treated.
Thereafter, 10 parts by mass of the resin (B1-1) and 1 part by mass of the dialkoxysilane compound (B21-1) were added, adjusted to pH 2 with nitric acid as an acidic catalyst, and then reacted at 50 ° C. for 5 hours.
Thereafter, the pH was adjusted to 6 to 8 with sodium hydroxide, 0.5 part of JAGUAR HP-105 (manufactured by Rhodia) as a thickener, 2 parts by mass of amorphous inorganic powder (A2-1). Part by mass was added and stirred and mixed uniformly with a homomixer to obtain a white liquid coating composition having a nonvolatile content of 6.5% by mass.

On the surface of an iron test piece (7 cm × 6 cm, water contact angle 70 °) that was acrylic-coated with an aqueous multipurpose spray (made by Asahi Pen Co., Ltd., white), an auto film An article with a coating film was obtained by applying with an applicator (product name PI-1210, manufactured by Tester Sangyo Co., Ltd.) and drying at 105 ° C. for 60 minutes.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 7.

Example 39
A dialkoxysilane compound (B21-2) is used in place of the dialkoxysilane compound (B21-1), the reaction is performed at pH 11 without adding an alkali catalyst, and the pH is adjusted to 6 to 8 with nitric acid after the reaction. Were operated in the same manner as in Example 37 to obtain an article with a coating film of Example 39.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 7.

[Examples 40 to 58, Comparative Examples 6, 7, 9, and 12]
Except having changed into the composition shown in Tables 7-13, it operated like Example 37 and obtained articles with a coating film of Examples 40-58 and comparative examples 6, 7, 9, and 12.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Tables 7-13.

[Comparative Example 10]
97.9 parts by mass of ion-exchanged water, 1 part by mass of Snowtex N (0.2 parts by mass in terms of non-volatile content), 0.14 parts by mass of Rika Surf P-10 (0.1 mass in terms of non-volatile content) Part) and 1 part by mass of 2-ethoxyethanol were uniformly mixed to obtain a coating composition having an active ingredient content of 1.3% by mass.

Trigger spray on the surface of an iron test piece (7cm x 6cm, water contact angle 70 °) with acrylic coating using the resulting coating composition using an aqueous versatile spray (made by Asahi Pen Co., Ltd., white) The product was coated with (product name TS8000-1, manufactured by Enomoto Kogyo Co., Ltd.) and naturally dried to obtain an article with a coating film.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 12.

[Comparative Example 11]
4 parts by mass of tetraalkoxysilane compound (B22-1), 18 parts by mass of isopropyl alcohol, 199.8 parts by mass of ST-O (39.96 parts by mass in terms of nonvolatile content), 0.2 of ST-OL After blending parts by mass (0.04 parts by mass in terms of non-volatile content) and adjusting the pH to 2 with nitric acid, the mixture was stirred and mixed uniformly using a disper. Then, reaction was performed at 50 degreeC for 2 hours. Thereafter, 658 parts by mass of ion-exchanged water and 2.64 parts by mass of BYK-346 (1.2 parts by mass in terms of non-volatile content) were added, and the mixture was uniformly stirred and mixed with a homomixer to obtain a non-volatile content of 5.1. A mass% coating composition was obtained.

Trigger spray on the surface of an iron test piece (7cm x 6cm, water contact angle 70 °) with acrylic coating using the resulting coating composition using an aqueous versatile spray (made by Asahi Pen Co., Ltd., white) (Product name TS8000-1, manufactured by Enomoto Kogyo Co., Ltd.) was applied and dried at 150 ° C. for 30 minutes to obtain an article with a coating film.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 12.

[Comparative Example 13]
The article with the coating film of Comparative Example 13 was obtained in the same manner as in Example 39 except that the formulation shown in Table 13 was changed.
About this article with a coating film, the contact angle before and after a flowing water test, the water film spreading width, and abrasion resistance were evaluated. The results are shown in Table 13.

  The coating composition of the present invention can impart excellent superhydrophilicity to the surface of the coated substrate. Furthermore, in the case where zinc oxide known as a deodorant or antibacterial agent is used for the fine particles in the coating composition, there is a possibility that deodorant and antibacterial properties can be imparted in addition to super hydrophilicity. For this reason, the coating composition and article with a coating film of the present invention can be widely applied to the surface of aluminum fins for heat exchangers of buildings, vehicles, and air conditioners, and is useful as a technology that has extremely high utility value in the industry.

Claims (5)

Hydrophilic fumed silica (A1) having an average particle size of 1 to 40 nm;
An amorphous inorganic powder (A2) having an average particle diameter of 0.1 to 500 μm and an apparent specific volume of 2 to 12 cm ³ / g;
Resin (B1), dialkoxysilane compound represented by the following formula (1) or a partially hydrolyzed condensate thereof (B21), and tetraalkoxysilane compound represented by the following formula (2) or a partially hydrolyzed condensate thereof A coating composition obtained by mixing at least one binder (B) selected from the group consisting of (B22).
Si (R ¹ ) (R ² ) (OR ³ ) (OR ⁴ ) (1)
(In the formula (1), R ¹ and R ² are each an alkyl group having 1 to 6 carbon atoms, an aminoalkyl group having 1 to 8 carbon atoms, or a glycidoxyalkyl group, and R ³ and R ⁴ are respectively (It is an alkyl group having 1 to 6 carbon atoms.)
Si (OR ⁵ ) (OR ⁶ ) (OR ⁷ ) (OR ⁸ ) (2)
(In Formula (2), R < ⁵ > -R < ⁸ > is a C1-C6 alkyl group, respectively.) As the binder (B),
The resin (B1);
The alkoxysilane compound or partial hydrolysis thereof comprising at least one selected from the group consisting of the dialkoxysilane compound or partial hydrolysis condensate thereof (B21) and the tetraalkoxysilane compound or partial hydrolysis condensate thereof (B22). The coating composition according to claim 1, wherein the condensate (B2) is used in combination. The hydrophilic fumed silica (A1), the resin (B1), the alkoxysilane compound or a partially hydrolyzed condensate (B2) thereof are mixed, and the hydrophilic fumed silica (A1) and the alkoxysilane are mixed. A compound or a partially hydrolyzed condensate thereof (B2) reacted with,
The coating composition according to claim 2, wherein the amorphous inorganic powder (A2) is mixed. The hydrophilic fumed silica (A1) and the alkoxysilane compound or a partially hydrolyzed condensate (B2) thereof mixed and reacted;
The resin (B1);
The coating composition according to claim 2, wherein the amorphous inorganic powder (A2) is mixed.   The article with a coating film which has the coating film which consists of a coating composition as described in any one of Claims 1-4 on the surface.