KR20190118963A - Water repellent film-forming composition and water repellent film - Google Patents

Abstract

Provided is a water repellent film forming composition which is chemically stable, has good storage stability, can be repeatedly used, and can form a water repellent film, particularly a super water repellent film, simply and reproducibly. The water-repellent film forming composition comprises: (a) polysilazane in which a monovalent hydrocarbon group having 3 to 20 carbon atoms substituted with fluorine is bonded to a silicon atom; (b) surface-untreated metal oxide nanoparticles, metal oxide nanoparticles having a monovalent hydrocarbon group having 1 to 20 carbon atoms which is fluorine-substituted on a surface or metal oxide nanoparticles having an alkylsilyl group or an alkoxysilyl group on a surface thereof; and (c) an aprotic solvent.

Description

WATER REPELLENT FILM-FORMING COMPOSITION AND WATER REPELLENT FILM}

The present invention relates to a composition for forming a water repellent coating and a water repellent coating for forming a water repellent coating on a substrate.

Rain and tap water are routinely covered on the exterior walls and glass of buildings, the body of automobiles, and the mirrors of bathrooms, and water droplets remain on the surfaces. Since various inorganic salts and microorganisms are dissolved in rain water and tap water, when the water droplets are dried, they cause water stains and molds, which damage the aesthetics. In addition, the water droplets affect the glass itself or the surface of the mirror itself, affect the transmittance and reflectance of the light, thereby reducing the visibility.

Thus, studies have been conducted to suppress the adhesion of water droplets by forming a water-repellent film on the surface of solid materials such as metals, ceramics, glass, and resins. Thus, the material which imparted water repellency to the surface is improved in aesthetics by being used in various fields such as glass of a building or a vehicle, a body of a car or a train, a cover glass of a solar panel, a mirror of a bathroom or a panel around a kitchen. The maintenance work can be reduced or unnecessary.

When the contact angle with respect to water of a solid surface exceeds 90 degrees, it is called water repellency. However, if water droplets remain, even if it shows water repellency, the said problem is not solved. Therefore, it is important to improve the fallability of water droplets in addition to water repellency.

When the contact angle of the solid surface with water reaches 150 ° or more, it is called "super water-repellent". As shown in the leaves of plants such as lotus and taro, both water repellency (water repellency) and cloud (tumble) become good and antifouling properties. This is an excellent surface. Various methods have been proposed to imitate these plants and to form a film exhibiting super water repellency by combining minute unevenness and reduction of surface free energy.

For example, Patent Document 1 describes a surface modification of a substrate to which a treatment liquid containing a polycondensate of metal alkoxides, metal oxide fine particles and a silane compound having a fluoroalkyl group or an alkyl group is applied to the surface of the substrate, dried and heated. A method is proposed. Specifically, a porous metal oxide layer having a fine concavo-convex structure in which agglomerates of metal oxide fine particles are immobilized on a metal oxide matrix, and having a fluoroalkyl group or an alkyl group exhibiting water repellency on the surface and having a plurality of pores opened on the surface. It is a method of forming in the surface of a base material.

Patent Literature 2 discloses a superhydrophobic film-coated article in which a superhydrophobic film is coated on a surface of a substrate, wherein the superhydrophobic film is provided with a projection including a particulate aggregate, and a portion in which the projection is present in the coating area of the coating does not exist. A super water-repellent film-coated article has been proposed in which portions are mixed and irregularities due to protrusions are formed on the coating surface of the portion where the protrusions are present.

Specifically, a colloidal silica bonded in three dimensions, an alkylalkoxysilane, and an alkylalkoxysilane containing fluorine are mixed, and an acid catalyst containing water is added to co-hydrolyze and condensate the water-repellent material and the silicon oxide fine particles. It manufactures, using this as a dispersion liquid for water repellent treatment, apply | coats to glass by a flow-coating method, and air-drys to manufacture a super water-repellent glass substrate.

Patent Document 3 is a super water-repellent gas comprising a base, a base film having minute irregularities formed on the surface of the base, and a water repellent coating formed on the minute unevenness of the base film, wherein the surface shape of the water repellent coating is a particulate protrusion. And a super water-repellent gas composed of columnar projections having a height measured from the surface of the substrate rather than the particulate projections has been proposed.

Specifically, a decamethylcyclopentasiloxane solution of tetrachlorosilane is prepared as a coating liquid for forming an uneven base film, which is a base film mainly composed of silica, and separately decamethylcyclopentasiloxane of heptadecafluorodecyltrichlorosilane. The solution is prepared as a water repellent agent. Then, the coating liquid for forming the uneven underlayer film on the surface of the windshield glass for automobiles is applied by a flow coating method, and again by applying a water repellent agent, and standing still, washing with ethanol to completely wash the surface of the water repellent agent, and then drying it naturally. To produce a water-shielded windshield glass.

In patent document 4, the film | membrane which the film | membrane which has the silicon oxide which has micro unevenness | corrugation as a main component on the surface is coat | covered, and the coating | cover coating article comprised by micro protrusions and columnar protrusions is proposed. As a manufacturing method thereof, it has been reported that a coating film having the above-mentioned uneven structure can be formed by applying a coating solution in which tetrachlorosilane is dissolved in a solvent containing silicone oil as a main component. In addition, as an application example, a decamethylcyclopentasiloxane solution of heptadecafluorooctyltrichlorosilane is applied by a flow coating method on a film having a fine concavo-convex structure and allowed to stand, and washed with ethanol to completely remove the excess silane solution. After washing, it is dried naturally and the water-repellent glass is obtained.

Patent Document 5 includes a base material and a water repellent transparent film on the surface of the base material, wherein the water repellent transparent film consists of an inorganic oxide fine particle layer containing inorganic oxide fine particles and an overcoat layer on the inorganic oxide fine particle layer, and the surface of the water repellent transparent film. It has this uneven structure, the ratio of the average height of the said convex part, the distance between average convex parts (pitch width), the average height, and the said distance between the said average convex parts is prescribed | regulated to a specific range, and the surface of the convex part of the said uneven structure further removes fine unevenness | corrugation. The base material provided with the water-repellent transparent film which has is proposed.

As a manufacturing method of the base material in patent document 5, for example, (A) Tetraethoxysilane and water are added to the methanol dispersion liquid of the alumina microparticles which have a specific average particle length and average particle width, and these are made to react, Surface-treating and diluting with a solvent to obtain a surface-treated alumina fine particle dispersion, and applying the surface-treated alumina fine particle dispersion onto a substrate to cure it to form an inorganic oxide fine particle layer; (B) tridecafluorooctyl The remethoxysilane is hydrolyzed by reacting with water using an acid catalyst in alcohol, hydrolyzed, and coated with an inorganic oxide fine particle layer by applying a coating liquid for forming an overcoat layer, which is diluted with a solvent and adjusted in concentration, and heated and cured. The manufacturing method including the process of obtaining the base material with a film is made It is. Moreover, it is proposed to form a primer layer on a base material before a process (A), and to form a binder layer on an inorganic oxide fine particle layer between a process (A) and a process (B).

Japanese Patent Laid-Open No. 11-172455 Japanese Patent Laid-Open No. 2005-343016 International Publication No. 2003/039856 Japanese Patent Laid-Open No. 2004-137137 Japanese Patent Publication No. 2014-124913

However, in the method of patent document 1, since the molecular weight of the silane compound used for forming a water repellent film is small, when a compound with low reactivity like an alkoxysilane, a silane compound is removed from the process liquid for water repellent film formation, or a water repellent film. It may volatilize and lose.

In the case of patent document 2 and patent document 5, although the alkoxysilanes are used as a material which forms a water repellent film, since the reactivity is low in that state, the catalyst for hydrolysis, such as water and nitric acid, hydrochloric acid, is added. Since hydrolysis catalysts such as nitric acid and hydrochloric acid are condensation catalysts simultaneously, hydrolysis and condensation of alkoxysilanes in the coating liquid proceed simultaneously. Therefore, the coating liquid is not necessarily stable, and insoluble solids may sometimes precipitate during storage.

In the case of Patent Literature 3 and Patent Literature 4, in the step of forming a water repellent coating, chlorosilanes having very high reactivity with respect to moisture and the substrate are used as materials, so stability in storage of the coating liquid is low. .

The present invention has been made in view of the above circumstances, and is chemically stable, has a good storage stability, can be repeatedly used, and can form a water-repellent film that can be easily and reproducibly formed, particularly a super water-repellent film. It is an object to provide a composition for.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to achieve the said objective, the present inventors discovered that it is possible to solve the said subject by using polysilazane which has a specific structure, and came to this invention.

That is, the present invention provides the composition for water repellent coating and the water repellent coating described below.

〔One〕

The composition for water repellent film formation containing the following (a), (b) and (c) component.

(a) a polysilazane in which a C 3 to C 20 monovalent hydrocarbon group which may be substituted with fluorine is bonded to a silicon atom,

(b) untreated metal oxide nanoparticles, metal oxide nanoparticles having a monovalent hydrocarbon group having 1 to 20 carbon atoms which may be fluorine-substituted on the surface, or metal oxide nanoparticles having an alkylsilyl group or an alkoxysilyl group on the surface thereof, and

(c) aprotic solvents

〔2〕

The composition for water repellent film formation as described in [1] whose (a) component is polysilazane represented by following General formula (1).

(In formula, R may be same or different, respectively, and represents the C3-C20 monovalent hydrocarbon group which may be substituted. R ^a and R ^b may be same, different, respectively, and C1-C may be fluorine-substituted. A monovalent hydrocarbon group of 20. m is an integer from 1 to 100, and n and p are each an integer from 0 to 100, provided that the sum of m, n and p is an integer from 4 to 300.)

[3]

(b) The metal oxide nanoparticles having a C3-C20 monovalent hydrocarbon group which may be fluorine-substituted through a silicon atom by being surface-treated with polysilazane represented by the general formula (1). The composition for water repellent film formation as described in phosphorus [2].

〔4〕

(b) The composition for water-repellent film formation in any one of [1]-[3] whose metal oxide nanoparticle is silica.

[5]

(a) polysilazane in which a C3-C20 monovalent hydrocarbon group optionally substituted with fluorine is bonded to a silicon atom, and

(b) untreated metal oxide nanoparticles, metal oxide nanoparticles having a monovalent hydrocarbon group having 1 to 20 carbon atoms which may be fluorine-substituted on the surface, or metal oxide nanoparticles having an alkylsilyl group or an alkoxysilyl group on the surface thereof

Water repellent coating comprising a.

According to the present invention, a composition for forming a water repellent coating which has good storage stability, can be used repeatedly, and which can form a water repellent coating, particularly a super water repellent coating, easily and reproducibly can be obtained. Moreover, by using the composition of this invention, the film excellent in water repellency and water droplet fall property, and durable can be obtained.

The composition for water repellent film formation of this invention,

(a) a polysilazane in which a C 3 to C 20 monovalent hydrocarbon group which may be substituted with fluorine is bonded to a silicon atom,

(b) untreated metal oxide nanoparticles, metal oxide nanoparticles having a monovalent hydrocarbon group having 1 to 20 carbon atoms which may be fluorine-substituted on the surface, or metal oxide nanoparticles having an alkylsilyl group or an alkoxysilyl group on the surface thereof, and

(c) aprotic solvents

It contains.

Hereinafter, each component is demonstrated in detail.

<(a) polysilazane>

Polysilazane is a high molecular compound which has a structure in which a silicon atom and a nitrogen atom are alternately arranged. For example, commercially available perhydropolysilazane is a polysilazane in which a hydrogen atom is bonded without an organic substituent on a silicon atom, and is a material exhibiting hydrophilicity when a film is formed. In contrast, in the polysilazane used in the present invention, since a monovalent hydrocarbon group having 3 to 20 carbon atoms is bonded to the silicon atom, a film having a low surface free energy can be formed and exhibits water repellency. Moreover, the surface free energy of a film can be further reduced by fluorine substitution of the said monovalent hydrocarbon group.

It is preferable that the polysilazane used in this invention is polysilazane represented by following General formula (1).

(In formula, R may be same or different, respectively, and represents the C3-C20 monovalent hydrocarbon group which may be substituted. R ^a and R ^b may be same, different, respectively, and C1-C may be fluorine-substituted. A monovalent hydrocarbon group of 20. m is an integer from 1 to 100, and n and p are each an integer from 0 to 100, provided that the sum of m, n and p is an integer from 4 to 300.)

In the said General formula (1), R may be same or different, respectively, and may represent C3-C20, Preferably C3-C16, More preferably, C1-C16 monovalent hydrocarbon group may be substituted by fluorine. . Examples of the substituent R include propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, Straight-chain aliphatic saturated hydrocarbon groups such as heptadecyl group, octadecyl group, nonadecyl group and eicosyl group; Isopropyl group, isobutyl group, 2-butyl group, tert-butyl group, isopentyl group, 2-pentyl group, 3-pentyl group, tert-pentyl group, isohexyl group, 2-ethylhexyl group, isooctyl group, etc. Branched aliphatic saturated hydrocarbon groups; Aliphatic unsaturated hydrocarbon groups such as allyl group, butenyl group, metalyl group, pentenyl group, hexenyl group, octenyl group, decenyl group; Aromatic hydrocarbon groups such as phenyl group, tolyl group, xylyl group and mesityl group; Aralkyl groups such as benzyl, phenylethyl, phenylpropyl and phenylbutyl; Fluorine-substituted aliphatic hydrocarbon groups such as 3,3,3-trifluoropropyl group, nonafluorohexyl group, tridecafluorooctyl group, and heptadecafluorodecyl group; Fluorine substitution such as pentafluorophenyl group, 3,5-difluorophenyl group, 3-fluorophenyl group, 4-fluorophenyl group, 3-trifluoromethylphenyl group, 3,5-bis (trifluoromethyl) phenyl group Aromatic hydrocarbon groups; Pentafluorophenylethyl group, pentafluorophenylpropyl group, pentafluorophenylbutyl group, 3,4,5-trifluorophenylpropyl group, 2,4-difluorophenylpropyl group, 3,4-difluoro Rophenylpropyl group, 3,5-difluorophenylpropyl group, 2-fluorophenylethyl group, 2-fluorophenylpropyl group, 3-fluorophenylethyl group, 3-fluorophenylpropyl group, 4-fluoro And fluorine-substituted aralkyl groups such as phenylethyl group, 4-fluorophenylpropyl group, 4- (trifluoromethyl) phenylpropyl group, and 3,5-bis (trifluoromethyl) phenylpropyl group. Among these, a linear or branched aliphatic saturated monovalent hydrocarbon group, an aliphatic unsaturated monovalent hydrocarbon group, or a fluorine-substituted aliphatic saturated monovalent hydrocarbon group is preferable from the viewpoint of lowering the surface free energy of the film.

In said general formula (1), R ^<a> and R <^b> may be same or different, respectively, and may be C1-C20 which may be substituted by fluorine, Preferably C1-C10, More preferably, C1-C5 1 Represents a hydrocarbon group. Examples of the substituents R ^a and R ^b include aliphatic unsaturated monovalent hydrocarbon groups such as alkyl groups such as methyl groups and ethyl groups, and vinyl groups, in addition to the substituents exemplified as substituents R. When these carbon number has a substituent, the surface free energy of a film rises, but if these substituents are introduce | transduced as needed, the solubility and viscosity of polysilazane can be adjusted to an appropriate range.

The polysilazane represented by General formula (1) does not necessarily need to contain the repeating unit which has substituents R ^a and R ^b . However, by having these repeating units, physical properties, such as molecular weight, solubility, and viscosity of polysilazane, can be adjusted to an appropriate range.

In the said General formula (1), m is an integer of 1-100, Preferably it is 4-50, n and p are 0-100, respectively, Preferably it is an integer of 0-50. Provided that the sum of m, n and p is 4 to 300, preferably 4 to 100, and more preferably 4 to 50. That is, the polysilazane represented by General formula (1) necessarily contains the repeating unit which has a substituent R. Thereby, when forming a film using the composition of this invention, surface free energy can be reduced.

Although the ratio of m, n, and p is not limited, The ratio of m / (m + n + p) becomes like this. Preferably it is 0.01-1, More preferably, it is 0.1-1, More preferably, it is 0.25-1. When this ratio is less than 0.01, the influence of the substituent R on the surface free energy of the film is small, and a water repellent film may not be obtained, or the molecular weight of the polysilazane is lowered to become a volatile component, and the film properties are stable. It may not be.

Moreover, the weight average molecular weight of polystyrene conversion by the gel permeation chromatography of polysilazane (it describes as "GPC" hereafter) becomes like this. Preferably it is 300-30,000, More preferably, it is 500-10,000. In addition, the measurement conditions of GPC are as mentioned later.

The compounding quantity of (a) component in the composition of this invention becomes like this. Preferably it is 0.001-50 mass% of the whole composition, More preferably, it is 0.01-30 mass%, More preferably, it is 0.01-10 mass%. If it is less than 0.001 mass%, a film may become too thin and sufficient water repellency may not be obtained, and when it exceeds 50 mass%, the viscosity of a composition may become high too much. As described later, when the present composition is prepared while the surface treatment of the component (b) is carried out with the component (a), the theoretical addition amount of the component (a) is calculated based on the specific surface area and the addition amount of the component (b). In that case, it is preferable to exist in the said range.

<(b) Metal Oxide Nanoparticles>

As the metal oxide nanoparticles used in the present invention, at least one selected from silica, alumina, titania, zirconia, zinc oxide, tin oxide, cerium oxide, copper oxide, chromium oxide, cobalt oxide, iron oxide, manganese oxide, nickel oxide and the like Nanoparticles containing a metal oxide are mentioned. Among these, nanoparticles containing at least one metal oxide selected from silica, alumina, titania, zirconia, zinc oxide, tin oxide, and cerium oxide are preferable, and fine particles containing silica, alumina, titania, zirconia Is particularly preferred. It is most preferable to use fumed silica, which is a fine particle consisting substantially of silica.

The average primary particle diameter of the said metal oxide nanoparticles becomes like this. Preferably it is 5-200 nm in diameter, More preferably, it is the range of 10-150 nm in diameter, More preferably, it is 10-50 nm in diameter. If the particle diameter is less than 5 nm in diameter, unevenness effective for the film may not be obtained. On the other hand, if the particle diameter exceeds 200 nm, the transparency of the film may be impaired. In addition, in this invention, the value of an average primary particle diameter is the value measured by the scanning electron microscope (SEM).

In the case of fumed silica, the average primary particle diameter correlates with the value of the specific surface area which can be measured by the BET method. For example, if the specific surface area is 50 m 2 / g, the average primary particle diameter is about 30 nm, if the specific surface area is 200 m 2 / g, the average primary particle diameter is about 12 nm, and if the specific surface area is 300 m 2 / g, the average 1 The primary particle diameter is about 7 nm. When using fumed silica, it is preferable that the specific surface area is 30-500 m <2> / g, More preferably, it is 50-350 m <2> / g.

As the component (b), in addition to the surface untreated metal oxide nanoparticles, metal oxide nanoparticles having a C1-C20 monovalent hydrocarbon group which may be hydrophobized in advance and may be fluorine-substituted on its surface may be used. Examples of the metal oxide nanoparticles which have been hydrophobized in advance are the surfaces of the metal oxide nanoparticles which are commercially available, for example, under the trade names Aerosil R805, Airoxide T805, Airoxide NKT90, and Airoxide AluC805 (manufactured by Nippon Aerosil). Carbon number such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl An alkyl group of 1 to 20, preferably 1 to 10, or the same substituent as described for R ^a and R ^b of the compound of formula (1) is introduced; trade names Aerosil R972, Aerosil R974, Aerosil R976, Dialkyl silyl groups, such as a dimethyl silyl group, such as aerosil RX50, aerosil RX200, aerosil RX300, aerosil R812 (made by Nippon Aerosil Co., Ltd.), HDKH15, HDKH20, HDKH30 (made by Asahi Kasei Barker Silicone), trimethylsilyl group, tree The surface-treated trialkylsilyl group having preferably 1 to 6, more preferably 1 to 3 carbon atoms, such as a silyl group, tert-butyldimethylsilyl group, triisobutylsilyl group, and triisopropylsilyl group, may be used. Can be.

As the component (b), metal oxide nanoparticles in which an alkoxysilyl group exists on the surface of the metal oxide nanoparticles may be used. When an alkoxysilyl group exists on the surface of the metal oxide nanoparticles, since the alkoxysilyl group on the surface of the metal oxide nanoparticles and the polysilazane of the component (a) undergo a hydrolysis condensation reaction to form a covalent bond, the durability of the film Increases.

The alkoxysilyl group preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms of the alkyl group of the alkoxy group, and specifically, trimethoxysilyl group, triethoxysilyl group, and tripro Trialkoxy silyl groups, such as a foxy silyl group, a triisopropoxy silyl group, a diisopropoxy methoxy silyl group, a dimethoxy isopropoxy silyl group; Dialkoxysilyl groups such as dimethoxymethylsilyl group and diethoxymethylsilyl group; Monoalkoxy silyl groups, such as a methoxy dimethyl silyl group, an ethoxy dimethyl silyl group, an isopropoxy dimethyl silyl group, a methoxy diethyl silyl group, a methoxy dipropyl silyl group, a methoxy diisopropyl silyl group, etc. are mentioned.

There are various methods for introducing an alkoxysilyl group to the surface of the metal oxide nanoparticles, but a method of reacting a hydroxyl group on the surface of the surface-treated metal oxide nanoparticles with an alkoxysilylating agent is preferable. Examples of the alkoxysilylating agent include alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane and methyltriethoxysilane, tetramethoxysilane oligomer, tetraethoxysilane oligomer and methyltrimethoxysilane oligomer. Alkoxysilane oligomers, such as these; Alkoxy halosilanes such as chlorotrimethoxysilane, chlorotriethoxysilane, chlorodimethoxymethylsilane and chlorodiethoxymethylsilane; Alkoxy silazanes such as trimethoxysilyldimethylamine and trimethoxysilyldiethylamine; 1-trimethoxysilyloxy-1-methoxypropene, 1-trimethoxysilyloxy-1-ethoxypropene, 1-trimethoxysilyloxy-1-butoxypropene, 1-trimethoxy Silyloxy-1-methoxy-2-methylpropene, 1-triethoxysilyloxy-1-ethoxypropene, 1-dimethoxymethylsilyloxy-1-methoxypropene, 1-dimethoxymethylsilyl To oxy-1-ethoxypropene, 1-dimethoxymethylsilyloxy-1-octyloxypropene, 1-diethoxymethylsilyloxy-1-methoxypropene, 1-diethoxymethylsilyloxy-1- Alkoxy silyl keten acetals, such as a methoxy propene, 1-methoxy dimethyl silyloxy- 1-methoxy propene, and 1-methoxy dimethyl silyloxy- 1- ethoxy propene, etc. are mentioned. Among them, the alkoxysilylketenacetal is a neutral alkoxysilylating agent, and is preferable in view of easy removal of byproducts.

The introduction amount of the alkoxysilyl group is preferably 0.1 to 1, more preferably 0.3 when the saturation introduction amount of the metal oxide nanoparticles used as the component (b) is 1 from the viewpoint of the dispersibility of the metal oxide nanoparticles. To 1, more preferably from 0.5 to 1.

In order to determine the saturated introduction amount of the alkoxysilyl group, for example, the surface-untreated metal oxide nanoparticles and the above-mentioned alkoxysilylating agent are mixed at a constant ratio, and the consumption amount (or remaining amount) of the alkoxysilylating agent is determined by gas chromatography. It can be determined by obtaining. Although the alkoxy silylating agent is in contact with the metal oxide nanoparticles, the amount of the alkoxysilyl group introduced in the state in which it is not consumed is a saturated introduction amount.

When alkoxysilylating the surface of the metal oxide nanoparticles using the alkoxysilylating agent described above, the alkoxysilylating agent and the metal oxide nanoparticles may be contacted in the presence or absence of a solvent.

As a solvent which can be used, if it is an aprotic solvent which does not react with an alkoxy silylating agent, there will be no restriction | limiting in particular, For example, Hydrocarbon solvent, such as hexane, heptane, octane, isooctane, nonan, decane, toluene, xylene, mesitylene; Hydrocarbon mixed solvents, such as an isoparaffinic solvent and a naphthenic solvent: Ketones, such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; Nitriles such as acetonitrile, propionitrile and benzonitrile; Amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone; Ethers such as diethyl ether, dipropyl ether, diisopropyl ether, tetrahydrofuran, cyclopentylmethyl ether, dibutyl ether, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether and dipropylene glycol dimethyl ether solvent; Ester solvents such as ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, methoxyethyl acetate, and hexyl acetate. These solvents may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, alkoxy silylation can also be performed by using a liquid alkoxy silylating agent excessively, without a solvent.

In addition, the silanol remaining in the untreated metal oxide nanoparticles or the metal oxide nanoparticles having the monovalent hydrocarbon group, the alkylsilyl group or the alkoxysilyl group described above is subjected to surface treatment using polysilazane of component (a) to obtain silicon. What substituted substituent R and R ^<a> , R <^b> on the surface through an atom can be used. Thereby, compatibility with the polysilazane of (a) component becomes favorable.

As a compounding quantity of polysilazane when surface-treating untreated metal oxide nanoparticles using polysilazane of (a) component, the minimum coating area of polysilazane (the repetition of polysilazane) by following formula (I) Minimum area covered by 1 g of units) can be calculated, and the minimum amount of polysilazane calculated by the following formula (II) can be aimed at. However, especially when the substituent of polysilazane is large, surface treatment may be completed even if it is addition amount less than the calculated minimum addition amount. In the present invention, from the viewpoint of obtaining good water repellency and water droplet decay, the blending amount of polysilazane in the case of surface treatment of the metal oxide nanoparticles with polysilazane is preferably at least the minimum amount, more preferably. 1.3 times or more, More preferably, it is 2 times or more.

The method of surface-treating the metal oxide nanoparticles with polysilazane is not particularly limited, and the metal oxide nanoparticles may be mixed with the polysilazane and surface-treated by a known method. It is preferable to carry out by the method of adding and mixing polysilazane, after disperse | distributing a particle | grain in the (c) solvent mentioned later.

Although it is preferable to change the compounding quantity of (b) component in the composition of this invention according to the kind of polysilazane of (a) component, Preferably it is 0.001-30 mass% of the whole composition, More preferably, 0.01-10 mass%, More preferably, it is 0.01-5 mass%. When it exceeds 30 mass%, the viscosity of a composition will become high too much and a composition may not become uniform. If it is less than 0.001 mass%, a film may become too thin and sufficient water repellency may not be obtained.

<(c) Aprotic Solvent>

As described later, the film can be formed on the substrate by various coating methods using the composition for water repellent coating of the present invention, but the solvent is added to the composition of the present invention because the viscosity is adjusted according to the coating method. .

As a solvent which can be used, if it is an aprotic solvent which does not react with the polysilazane represented by General formula (1), there will be no restriction | limiting in particular, For example, hexane, heptane, octane, isooctane, nonane, decane, toluene, xylene, Hydrocarbon solvents such as mesitylene; Hydrocarbon mixed solvents, such as an isoparaffinic solvent and a naphthenic solvent: Ketones, such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; Nitriles such as acetonitrile, propionitrile and benzonitrile; Amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone; Ethers such as diethyl ether, dipropyl ether, diisopropyl ether, tetrahydrofuran, cyclopentylmethyl ether, dibutyl ether, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether and dipropylene glycol dimethyl ether solvent; Ester solvents such as ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, methoxyethyl acetate, and hexyl acetate. These solvents may be used alone or in combination of two or more kinds thereof.

Although the compounding quantity of the solvent of (c) component in the composition for water-repellent film formation of this invention can change arbitrarily according to the viscosity of the polysilazane which is (a) component, and also according to a coating method or a required film thickness, it is preferable. Preferably it is 10-99.9 mass% of the whole composition, More preferably, it is 30-99.5 mass%, More preferably, it is 50-99.5 mass%. If it is less than 10 mass%, the viscosity of a composition becomes high too much and the solubility (dispersibility) of (a) component and (b) component may become inadequate. When it exceeds 99.9 mass%, the film may become too thin and sufficient water repellency may not be obtained.

<Other ingredients>

In the composition of the present invention, as long as it does not impair the effects of the present invention, as other components, additives such as pigments, dyes, dispersants, viscosity modifiers, leveling agents, and organic groups on surfaces other than the component (b) You may contain the metal oxide nanoparticles which do not have.

<Composition for Water Repellent Film Formation>

The composition for water repellent film formation of this invention mixes (a) component, (b) component, (c) component, and other components as needed, and (a) component and (b) component of (c) component It is obtained by dissolving or dispersing in a solvent. The method of mixing is arbitrary, For example, mixing apparatuses, such as a stirrer and various mixers, can be used. Moreover, the method of ultrasonic irradiation is also effective.

When untreated metal oxide nanoparticles or metal oxide nanoparticles having a monovalent hydrocarbon group, an alkylsilyl group or an alkoxysilyl group on the surface are subjected to surface treatment using polysilazane of component (a), the surface treatment is previously performed. After performing, the remaining (a) component, the surface-treated metal oxide nanoparticles, and (c) component may be mixed, and a monovalent hydrocarbon group, an alkylsilyl group, The metal oxide nanoparticles having an alkoxysilyl group may be mixed with the component (c) and subjected to surface treatment while mixing and dispersing to obtain the present composition.

The water-repellent film-forming composition of the present invention thus obtained is a homogeneous solution or dispersion without containing precipitates or gels and is chemically stable, so that protonic compounds that decompose polysilazane, such as water or methanol, are not mixed. Unless irreversible, an insoluble matter will not be formed, unless it becomes a non-uniform mixture. Therefore, it can be used without changing performance over a long period of time. Moreover, since polysilazane acts as a moisture absorbing agent, even when a small amount of moisture is mixed, deterioration of a composition can be prevented.

<Base material>

Since the polysilazane of (a) component is excellent in adhesiveness with respect to the surface of a base material, the composition for water repellent film formation of this invention can be used with respect to various base materials. For example, it is possible to apply | coat to base materials, such as a metal, resin, glass, ceramics, these composite materials, and to form the water repellent film of this invention.

<Application method>

As a coating method of the composition for water repellent film formation of this invention, the method of wetting a composition uniformly on the surface of a base material is required. As a specific method, a flow coating method, the dip coating method, the curtain coating method, the spin coating method, the spray coating method, the bar coating method, etc. are mentioned, for example. What is necessary is just to select the appropriate coating method according to the kind and shape of a base material, and the required film thickness.

<Water repellent film>

After apply | coating the composition for water repellent film formation of this invention to the surface of a base material, the water repellent film of this invention can be obtained by a simple method by removing the aprotic solvent which is (c) component. As a method of removing a solvent, the method of volatilizing by normal pressure or a reduced pressure is common. At this time, it is also possible to shorten the time by heating.

When the aprotic solvent is removed or after the aprotic solvent is removed, part or all of the polysilazane can be converted into polysiloxane by acting water on the surface of the coating. This operation is preferable because the durability of the film is improved. As a method of making water act, it can be performed by arbitrary methods, such as standing still in the environment in which water vapor of about 10 to 95% RH exists, or immersing in water.

Although the thickness of the water repellent film of this invention is arbitrary, Generally, average thickness is 10 nm-50 micrometers, More preferably, it is 50 nm-10 micrometers. If it is less than 10 nm, a film may become too thin and sufficient water repellency may not be obtained. When it exceeds 50 micrometers, a crack may arise at the time of removing a solvent.

The water repellent coating of the present invention has high water repellency and water droplet decay. Although the contact angle with respect to water which is an index of water repellency of a film becomes 150 degree or more typically, and shows super water repellency, Preferably it is 160 degree or more. In addition, although the fall angle of the water (the angle at which the droplet starts to fall), which is an index of the dropping property of the drop, varies depending on the size of the drop, it is typically 5 ° or less, preferably 3 ° or less, more preferably 1 It is below °. Moreover, the fall rate of water is also large on the film which shows the contact angle of 160 degrees or more, and is preferable.

EXAMPLE

Hereinafter, although a synthesis example, the Example of this invention, and a comparative example are described, this invention is not limited to these Examples at all.

Synthesis Example 1 Synthesis of Octyl Polysilazane

Octyltrichlorosilane is substituted with nitrogen in the 1 L four-necked glass flask equipped with a stirrer, a gas feed tube, a thermometer, and a reflux cooler, and a nitrogen gas is blown through the open end of the reflux cooler to prevent mixing of outside air. 309.6 g (1.25 mol) and 500 mL of toluene were added and stirred to obtain a uniform solution. While stirring the contents at room temperature, ammonia gas was fed through the feed tube at a rate of about 0.62 mol / hr in solution. The feed of ammonia was continued for 7.1 hours while cooling so that the temperature of the content might not exceed 40 degreeC. Thereafter, the feed of ammonia was stopped, nitrogen gas was blown through the feed tube at a rate of 0.5 L / min for 6 hours, and excess ammonia gas was purged. The white solid which generate | occur | produced was separated by filtration by the membrane filter, and the colorless transparent solution was obtained. The solution was concentrated under reduced pressure and vacuum dried at room temperature to obtain 142.8 g of a cloudy oily octyl polysilazane.

The weight average molecular weight of the polystyrene conversion molecular weight by GPC was 2420, and the number average molecular weight was 1900. In addition, the measurement conditions of GPC are as follows.

[GPC Terms]

Device: Prominence GPC system (manufactured by Shimadzu Seisakusho Co., Ltd.)

Column: LF-404 (4.6 mm x 250 mm) (manufactured by Shodex) x 2

Eluent: tetrahydrofuran (THF)

Flow rate: 0.35ml / min

Detector: RI

Column thermostat temperature: 40 ℃

Standard material: polystyrene

Infrared absorption spectra (FT-IR) were measured, 893 cm ^-1 (Si-N-Si), 1152 cm ^-1 (NH), 2853 cm ^-1 , 2920 cm ^-1 (CH), 3384 cm ^-1 ( Absorption was observed in NH), and it was supported that the target octyl polysilazane was produced.

Synthesis Example 2 Synthesis of Decyl Polysilazane

Decylpolysilazane was obtained as a white oily substance in the same manner as in Synthesis Example 1 except that 344.6 g (1.25 mol) of decyltrichlorosilane was used instead of octyl trichlorosilane.

The weight average molecular weight by GPC was 2970, and the number average molecular weight was 2230.

Synthesis Example 3 Synthesis of Hexyl Polysilazane

Hexyl polysilazane was obtained as a white oily substance in the same manner as in Synthesis example 1 except that 272.5 g (1.25 mol) of hexyltrichlorosilane was used instead of octyl trichlorosilane.

The weight average molecular weight by GPC was 1250, and the number average molecular weight was 1130.

Synthesis Example 4 Synthesis of Propyl Polysilazane

Propylene polychlorosilane was obtained in the same manner as in Synthesis Example 1 except that 221.9 g (1.25 mol) of propyltrichlorosilane was used instead of octyl trichlorosilane, and 1125 mL of cyclopentylmethyl ether was used instead of toluene. .

The weight average molecular weight by GPC was 890, and the number average molecular weight was 770.

Synthesis Example 5 Synthesis of (tridecafluorooctyl) (trifluoropropyl) polysilazane

The inside of a 300 mL four-necked glass flask equipped with a stirrer, a gas feed tube, a thermometer, and a reflux condenser was replaced with nitrogen, and a nitrogen gas was passed through the open end of the reflux condenser to prevent mixing of outside air. 4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyltrichlorosilane 54.2 g (112.5 mmol) and 3,3,3-trifluoropropyltrichlorosilane 8.68 g (37.5 mmol) and 135 mL of cyclopentylmethyl ether were added and stirred to obtain a uniform solution. While stirring the contents at room temperature, ammonia gas was fed through the feed tube at a rate of about 124 mmol / hr in solution. The feed of ammonia was continued for 4.8 hours while cooling so that the temperature of the content might not exceed 40 degreeC. Thereafter, the feed of ammonia was stopped, and nitrogen gas was blown through the feed pipe at a rate of 0.15 L / min for 6 hours to purge the excess ammonia gas. The white solid which generate | occur | produced was separated by filtration by the membrane filter, and the colorless transparent solution was obtained. The solution was concentrated under reduced pressure and vacuum dried at room temperature to obtain 39.3 g of a cloudy oil.

The weight average molecular weight of the polystyrene conversion molecular weight by GPC was 2750, and the number average molecular weight was 2500.

Infrared absorption spectrum (FT-IR) was measured, 898 cm ^-1 (Si-N-Si), 1141 cm ^-1 (CF), 1183 cm ^-1 (NH), 2946 cm ^-1 (CH), 3394 cm Absorption was observed in ^-1 (NH), and it was supported that the target (tridecafluorooctyl) (trifluoropropyl) polysilazane was produced.

Synthesis Example 6 Synthesis of Tridecafluorooctylpolysilazane

The inside of a 200 mL four-necked glass flask equipped with a stirrer, a gas feed tube, a thermometer, and a reflux condenser was replaced with nitrogen, and a nitrogen gas was passed through the open end of the reflux condenser to prevent mixing of outside air. 4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyltrichlorosilane 48.2 g (100 mmol) and 90 mL of metha xylene hexafluoride were added and stirred One solution was obtained. While stirring the contents at room temperature, ammonia gas was fed through the feed tube at a rate of about 79 mmol / hr in solution. The feed of ammonia was continued for 5.5 hours while cooling so that the temperature of the content might not exceed 40 degreeC. Thereafter, the feed of ammonia was stopped, and nitrogen gas was blown through the feed pipe at a rate of 0.15 L / min for 2 hours to purge the excess ammonia gas. The white solid which generate | occur | produced was separated by filtration by the membrane filter, and the colorless transparent solution was obtained. The solution was concentrated under reduced pressure and dried in vacuo at room temperature to give 25.4 g of a cloudy oil.

The weight average molecular weight of the polystyrene conversion molecular weight by GPC was 2840, and the number average molecular weight was 2680.

Infrared absorption spectrum (FT-IR) was measured, 932 cm ^-1 (Si-N-Si), 1141 cm ^-1 (CF), 1182 cm ^-1 (NH), 2945 cm ^-1 (CH), 3394 cm Absorption was observed in ^-1 (NH), and it was supported that the target tridecafluorooctylpolysilazane was produced.

Synthesis Example 7 Synthesis of Hexyl (Dimethyl) Polysilazane

A 500 mL four-necked glass flask equipped with a stirrer, a gas feed tube, a thermometer, and a reflux condenser is replaced with nitrogen, and a hexyltrichlorosilane is introduced into the open end of the reflux condenser to prevent outside air from entering. 165 mL was added and stirred with 32.9 g (150 mmol), dimethyldichlorosilane 6.5g (50 mmol), and toluene as a solvent, and the uniform solution was obtained. While stirring the contents at room temperature, ammonia gas was fed through the feed tube at a rate of about 150 mmol / hr in solution. The feed of ammonia was continued for 6 hours while cooling so that the temperature of the content might not exceed 40 degreeC. Thereafter, the feed of ammonia was stopped, and nitrogen gas was blown through the feed pipe at a rate of 0.15 L / min for 2 hours to purge the excess ammonia gas. The white solid which generate | occur | produced was separated by filtration by the membrane filter, and the colorless transparent solution was obtained. The solution was concentrated under reduced pressure and 18.9 g of a colorless oil was obtained by vacuum drying at room temperature.

The weight average molecular weight of the polystyrene conversion molecular weight by GPC was 1574, and the number average molecular weight was 1144.

In an infrared absorption spectrum ^{900㎝ -1, 1153㎝ -1 (Si-} N-Si), 1459㎝ -1, 2853㎝ -1 (FT-IR) hanba ^{measured, (CH), 3389㎝ -1 (} NH) Absorption was observed and it was supported that the target polysilazane was produced.

Synthesis Example 8 Preparation of Silica Particle Dispersion Having Trimethoxysilyl Group on Surface

In a glass container with a resin cap, 5.00 g of fumed silica (specific surface area 205 m 2 / g, trade name Rheolosyl QS-102, a dosing agent) was weighed, and 56.25 g of cyclopentylmethyl ether and 1-trimethoxysilyloxy 1.25 g of -1-ethoxypropene was added and ultrasonic irradiation was carried out for 1 hour while occasionally shaking to disperse the fumed silica uniformly. A white translucent and stable dispersion was obtained, and by the GC measurement of the dispersion, 1-trimethoxysilyloxy-1-ethoxypropene was lost and no volatile compound having a trimethoxysilyl group was produced. It turned out that it was judged that the trimethoxysilyl group was introduce | transduced into the silica surface.

Example 1

2 g of fumed silica (specific surface area 205 m 2 / g, trade name Rheolosyl QS-102, a dosing agent) was weighed into a glass container with a resin cap, and 77 g of cyclopentylmethyl ether and 20 g of dipropylene glycol dimethyl ether were added thereto. Ultrasonic irradiation was carried out for a minute to disperse the fumed silica. 1 g of octyl polysilazane obtained in Synthesis Example 1 was added, followed by ultrasonic irradiation again for 15 minutes to obtain a composition for forming a white semitransparent water repellent film. The composition was stable for at least 1 month at room temperature under airtight.

Subsequently, this composition was used as a coating liquid, and it applied on the soda glass substrate (made by Matsunami Glass) so that the film thickness might be about 1 micrometer after drying using a bar coater. Then, the water-repellent film was formed on the glass substrate by volatilizing a solvent in 25 degreeC and 50% RH environment of a coating film.

<Evaluation of the water repellent coating>

For the formed water repellent coating, contact angle (10 μL) and drop angle (20 μL) of pure water on the surface of the film were measured using a contact angle meter (DMs-401) made by Kyowa Kaimen Kagaku Co., Ltd. at 25 ° C and 50% RH. As a result, the contact angle was 163 ° and the tumble angle was 1 °. It was found that a water-repellent coating was obtained, which exhibited super water repellency and was very satisfactory in water droplets.

Subsequently, after immersing the soda glass substrate in which the water-repellent film was formed as mentioned above in 25 degreeC pure water for 1 hour, the contact angle and tumble angle were measured, The contact angle was 163 degree and the tumble angle was 1 degree.

Moreover, after this glass substrate was wash | cleaned with warm water for 1 hour using dishwashing dryer NP-TCM4 (made by Panasonic), the contact angle and tumble angle were measured, The contact angle was 163 degree and the tumble angle was 1 degree. The performance decline by water washing was not seen, and it was judged that the durable water-repellent film was formed.

Table 1 shows the measurement results of the compounding amount, stability, film thickness, contact angle, and tumble angle of the composition.

Example 2

Except having changed the coating film thickness by the bar coater into the film thickness shown in Table 1, it carried out similarly to Example 1, and obtained the composition for water-repellent film formation.

When the obtained composition was formed on the glass substrate similar to Example 1, the water-repellent film was shown, and super water-repellent property and the water fall of the water droplet were very favorable. Table 1 shows the results of measurement of the compounding amount, stability, film thickness, contact angle, and tumble angle of the composition.

Example 3

Except having made the addition amount of fumed silica and octyl polysilazane 1.5g each, it carried out similarly to Example 1, and obtained the composition for water-repellent film formation.

When the obtained composition was formed on the glass substrate similar to Example 1, the water-repellent film was shown, and super water-repellent property and the water fall of the water droplet were very favorable. Table 1 shows the results of measurement of the compounding amount, stability, film thickness, contact angle, and tumble angle of the composition.

Comparative Example 1

Except having changed the addition amount of fumed silica and octyl polysilazane as shown in Table 1, it carried out similarly to Example 1, and obtained the composition for water-repellent film formation.

The water repellent film was formed on the glass substrate similar to Example 1 using the obtained composition. Table 1 shows the results of measurement of the compounding amount, stability, film thickness, contact angle, and tumble angle of the composition.

The coating film obtained by the comparative example 1 which does not add fumed silica does not become super water-repellent.

[Examples 4 to 6]

Except having changed the kind of polysilazane to add to what is shown in Table 2, it carried out similarly to Example 1, and obtained the composition for water-repellent film formation.

When the water-repellent film was formed on the glass substrate similar to Example 1 using the obtained composition, all showed super water-repellent property and the water-repellent film with the very good fall property of the water droplet was formed. Table 2 shows the measurement results of the compounding amount, stability, film thickness, contact angle, and falling angle of the composition.

Example 7

In a glass container with a resin cap, 0.9 g of hydrophobic fumed silica (specific surface area 145 m 2 / g, trade name Aerosil RX200, manufactured by Nippon Aerosil Co., Ltd.) surface-modified with trimethylsilyl group was weighed, and cyclopentylmethyl ether 30.8 g, 8.0 g of dipropylene glycol dimethyl ether was added, mixed for 1 minute with a rotating revolution mixer, and the surface-modified fumed silica was dispersed. 0.3 g of octyl polysilazane obtained in Synthesis Example 1 was added and mixed again using a rotating revolution mixer for 5 minutes to obtain a composition for forming a white translucent water repellent coating. The composition was stable for at least 1 month at room temperature under airtight.

Subsequently, this composition was used as a coating liquid, and it applied on the soda glass substrate (made by Matsunami Glass) so that the film thickness might be about 1 micrometer after drying using a bar coater. Then, the water-repellent film was formed on the glass substrate by volatilizing a solvent in 25 degreeC and 50% RH environment of a coating film.

<Evaluation of the water repellent coating>

For the formed water repellent coating, contact angle (10 μL) and drop angle (20 μL) of pure water on the surface of the film were measured using a contact angle meter (DMs-401) made by Kyowa Kaimen Kagaku Co., Ltd. at 25 ° C and 50% RH. As a result, the contact angle was 163 ° and the tumble angle was 1 °. It was found that a water-repellent coating was obtained, which exhibited super water repellency and was very satisfactory in water droplets.

Example 8

Except having changed the polysilazane to add into (tridecafluorooctyl) (trifluoropropyl) polysilazane obtained by the synthesis example 5, it carried out similarly to Example 7, and obtained the composition for water-repellent film formation.

When the obtained composition was used, the water-repellent film was formed on the glass substrate similar to Example 7, and the water-repellent film which showed super water repellency and was very favorable for the water fall of the water droplet was formed.

Example 9

The polysilazane to be added was changed to tridecafluorooctylpolysilazane obtained in Synthesis Example 6, and 38.8 g of metha xylene hexafluoride was used as the solvent, except that the composition for water repellent coating was formed. Got it.

When the obtained composition was used, the water-repellent film was formed on the glass substrate similar to Example 7, and the water-repellent film which showed super water repellency and was very favorable for the water fall of the water droplet was formed.

Table 3 shows the results of measurement of the compounding amount, stability, film thickness, contact angle, and falling angle of the compositions of Examples 7 to 9.

Example 10

0.18 g of fumed silica (specific surface area 205 m 2 / g, trade name Rheolosyl QS-102, a dosing agent) was weighed into a glass container with a resin cap, and 6.10 g of cyclopentylmethyl ether and 1.60 g of dipropylene glycol dimethyl ether And 0.036 g of 1-trimethoxysilyloxy-1-ethoxypropene were added and ultrasonically irradiated for 30 minutes. A trimethoxysilyl group was introduced onto the silica surface to uniformly disperse the fumed silica in the solvent. Subsequently, a 50 mass% cyclopentylmethyl ether solution containing 0.06 g of octyl polysilazane obtained in Synthesis Example 1 was added and ultrasonically irradiated for another 15 minutes to obtain a composition for forming a white semitransparent water repellent film. The composition was stable for at least 1 month at room temperature under airtight. The manufacturing method of the composition of this Example is described as method A.

Subsequently, this composition was used as a coating liquid, and it applied on the soda glass substrate (made by Matsunami Glass) so that the film thickness might be about 1 micrometer after drying using a bar coater. Then, the water-repellent film was formed on the glass substrate by volatilizing a solvent in 25 degreeC and 50% RH environment of a coating film.

<Evaluation of the water repellent coating>

For the formed water-repellent coating, contact angle (10 μL) and drop angle (20 μL) of pure water on the surface of the membrane under conditions of 25 ° C. and 50% RH were measured using Kyowa Kaimen Kagaku Contact Angle System (DMs-401). As a result, the contact angle was 161 ° and the tumble angle was 1 °. It was found that a water-repellent coating was obtained, which exhibited super water repellency and was very satisfactory in water droplets.

Moreover, after this glass substrate was wash | cleaned with hot water for 1 hour using dishwashing dryer NP-TCM4 (made by Panasonic), the contact angle and tumble angle were measured, The contact angle was 162 degrees and the tumble angle was 1 degree. The performance decline by water washing was not seen, and it was judged that the durable water-repellent film was formed.

In addition, the total light transmittance and haze of the soda glass substrate which formed the water repellent film by the above-mentioned method were measured using the Suga Shikenki Haze Meter (HZ-V3), The total light transmittance is 92.7% and haze is 0.8%, It appeared to be a film with high transparency.

The compounding quantity of a composition, the contact angle, the fall angle, the total light transmittance, and the measurement result of haze are shown in Table 4.

[Examples 11 to 13]

Except having changed the compounding quantity of a composition as shown in Table 4, it carried out similarly to Example 10, and obtained the composition for water repellent film formation by the method A.

When the water-repellent film was formed on the glass substrate similar to Example 10 using the obtained composition, the water-repellent film which showed super water repellency and was excellent in the fall property of the water droplet was formed. The compounding quantity of a composition, the contact angle, the fall angle, the total light transmittance, and the measurement result of haze are shown in Table 4.

Comparative Example 2

The composition for water-repellent film formation was obtained by the composition shown in Table 4 without adding fumed silica and 1-trimethoxysilyloxy-1-ethoxypropene.

The water repellent film was formed on the glass substrate similar to Example 10 using the obtained composition. Table 4 shows the measurement results of the compounding amount, the contact angle, and the drop angle of the composition.

In Comparative Example 2 in which fumed silica was not added, a water repellent coating film was obtained, but the coating film did not become super water repellent.

* 1 total amount of cyclopentylmethyl ether in the composition

Example 14

1.50 g of silica particle dispersions having a trimethoxysilyl group obtained in Synthesis Example 8 were weighed into a glass container with a resin cap, and 4.62 g of cyclopentylmethyl ether, 1.02 g of dipropylene glycol dimethyl ether, and obtained in Synthesis Example 1 were obtained. A 25 mass% dipropylene glycol dimethyl ether solution containing 0.06 g of octyl polysilazane was added and mixed for 1 minute to obtain a composition for forming a white translucent water repellent coating. The composition was stable for at least 1 month at room temperature under airtight. The method for producing a composition of this example is described as Method B.

When the water-repellent film was formed on the glass substrate similar to Example 10 using the obtained composition, the water-repellent film which showed super water repellency and was excellent in the fall property of the water droplet was formed. The compounding quantity of a composition, the contact angle, the fall angle, the total light transmittance, and the measurement result of haze are shown in Table 5.

Example 15

Except having changed the compounding quantity of a composition as shown in Table 5, it carried out similarly to Example 14, and obtained the composition for water repellent film formation by the method B.

When the water-repellent film was formed on the glass substrate similar to Example 14 using the obtained composition, the water-repellent film which showed super water repellency and was excellent in the fall property of the water droplet was formed. The compounding quantity of a composition, the contact angle, the fall angle, the total light transmittance, and the measurement result of haze are shown in Table 5.

* 2 Compounding amount as fumed silica and 1-trimethoxysilyloxy-1-ethoxypropene used in Synthesis Example 8

* 3 The total amount of dipropylene glycol dimethyl ether in the composition

[Examples 16 to 18]

Except having changed the kind of polysilazane added and the compounding quantity of a composition as shown in Table 6, it carried out similarly to Example 10 or Example 14, and obtained the composition for water-repellent film formation by the method A or the method B.

When the obtained composition was formed on the glass substrate similar to Example 1, the water-repellent film was shown, and super water-repellent property and the water fall of the water droplet were very favorable. The compounding quantity of a composition, the contact angle, the fall angle, the total light transmittance, and the measurement result of haze are shown in Table 6.

* 1 total amount of cyclopentylmethyl ether in the composition

* 3 The total amount of dipropylene glycol dimethyl ether in the composition

Claims (5)

The composition for water repellent film formation containing the following (a), (b) and (c) component.
(a) a polysilazane in which a C 3 to C 20 monovalent hydrocarbon group which may be substituted with fluorine is bonded to a silicon atom,
(b) untreated metal oxide nanoparticles, metal oxide nanoparticles having a monovalent hydrocarbon group having 1 to 20 carbon atoms which may be fluorine-substituted on the surface, or metal oxide nanoparticles having an alkylsilyl group or an alkoxysilyl group on the surface thereof, and
(c) aprotic solvents The composition for water-repellent film formation of Claim 1 whose (a) component is polysilazane represented by following General formula (1).

(In formula, R may be same or different, respectively, and represents the C3-C20 monovalent hydrocarbon group which may be substituted. R ^a and R ^b may be same, different, respectively, and C1-C may be fluorine-substituted. A monovalent hydrocarbon group of 20. m is an integer from 1 to 100, and n and p are each an integer from 0 to 100, provided that the sum of m, n and p is an integer from 4 to 300.) (B) 3 to 20 carbon atoms which may be fluorine-substituted via a silicon atom because the (b) metal oxide nanoparticle is surface-treated with the polysilazane represented by the said General formula (1). The composition for water repellent film formation which has a valent hydrocarbon group on the surface. The composition for forming a water repellent coating according to any one of claims 1 to 3, wherein (b) the metal oxide nanoparticles are silica. (a) polysilazane in which a C3-C20 monovalent hydrocarbon group optionally substituted with fluorine is bonded to a silicon atom, and
(b) untreated metal oxide nanoparticles, metal oxide nanoparticles having a monovalent hydrocarbon group having 1 to 20 carbon atoms which may be fluorine-substituted on the surface, or metal oxide nanoparticles having an alkylsilyl group or an alkoxysilyl group on the surface thereof
Water repellent coating comprising a.