TWI798414B - Water repellent film-forming composition and water repellent film - Google Patents

Abstract

A composition is provided comprising (a) a polysilazane having a monovalent hydrocarbon group, (b) untreated metal oxide nanoparticles, metal oxide nanoparticles having a monovalent hydrocarbon group, or metal oxide nanoparticles having an alkylsilyl or alkoxysilyl group, and (c) an aprotic solvent. The composition has storage stability and is suitable for forming a film having water repellent, especially superhydrophobic properties.

Description

Composition for forming water-repellent film and water-repellent film

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

On the exterior walls or glass of buildings, car bodies, bathroom mirrors, etc., when daily rain or tap water falls, water droplets will remain on the surface. Various inorganic salts and microorganisms are dissolved in rainwater or tap water, so when the water droplets dry, it will cause water stains or mold, which will damage the appearance. In addition, the fact that water droplets adhere to the surface of the glass or mirror itself will affect the light transmittance or reflectivity and reduce the visibility.

Therefore, it has been examined 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 resin. In this way, materials that impart water repellency to the surface can be used in various fields such as glass of buildings or vehicles, bodywork of automobiles or trains, protective glass of solar cell panels, mirrors in bathrooms, and panels around kitchens. Improves aesthetics and reduces or eliminates maintenance.

When the contact angle of a solid surface to water exceeds 90°, it is said to be water-repellent, but even if water-repellency is exhibited, the above problems cannot be solved if water droplets remain. Therefore, in addition to the water repellency, it is also important to improve the drop performance of water droplets.

If the contact angle of the solid surface to water becomes more than 150°, it is called "super water repellency". For example, it can be seen in the leaves of plants such as lotus or taro, where water droplets repel (water repellency) and fall (drop) properties) all became good, and became a surface with excellent antifouling properties. Various methods of forming a coating exhibiting super water repellency by imitating these plants and combining minute bumps and lowering of surface free energy are proposed.

For example, Patent Document 1 proposes to apply a treatment liquid containing polycondensates of metal alkoxides, metal oxide particles, and silane compounds having fluoroalkyl or alkyl groups to the surface of a substrate, dry, and heat. Surface modification methods for substrates. Specifically, the aggregates of metal oxide fine particles are immobilized on the metal oxide substrate (matrix), and have a fine concave-convex structure showing water-repellent fluoroalkyl groups or alkyl groups exposed on the surface, forming a matrix on the surface of the substrate. A method of a porous metal oxide layer having a plurality of pores with openings on the surface.

Patent Document 2 proposes that, in a super water-repellent film-coated article coated with a super-water-repellent film on the surface of a substrate, the super-water-repellent film has protrusions composed of aggregates of fine particles, and the protrusions are mixed in the coating area of the film. A super water-repellent film-coated article in which protrusions are formed on the surface of the film at the portion where the protrusions are present and where there are no protrusions. Specifically, three-dimensional bonded colloidal silica, alkylalkoxysilane, and fluorine-containing alkylalkoxysilane are mixed, and a water-containing acid catalyst is added to prepare a water-repellent material and silicon oxide particles. The hydrolyzed and condensed polymer is used as a dispersion liquid for water-repellent treatment, coated on glass by a flow coating method, and allowed to dry naturally, thereby preparing a super water-repellent treated glass substrate.

Patent Document 3 proposes a super water-repellent substrate comprising a substrate, a base film having minute unevenness formed on the surface of the substrate, and a water-repellent coating formed on the micro-corrugation of the base film. The protrusions and the super water-repellent matrix are composed of columnar protrusions having a higher height as measured from the surface of the substrate than the particulate protrusions. Specifically, as a coating solution for forming a concave-convex base film of a base film mainly composed of silicon dioxide, a tetrachlorosilane decamethylcyclopentasiloxane solution was prepared, and heptadecafluorodecyltrichloro A solution of decamethylcyclopentasiloxane in silane is used as a water-repellent treatment agent. In addition, the surface of the windshield (windshield) for automobiles is coated with a coating solution for forming a concave-convex base film by a flow coating method, and then a water-repellent treatment agent is applied, left to stand, and the water-repellent surface is completely washed with ethanol. After applying the treatment agent, let it dry naturally to prepare a water-repellent treated windshield.

Patent Document 4 proposes an article coated with a film mainly composed of silicon oxide having microscopic unevenness on the surface, and the microscopic unevenness is a film-coated article composed of microscopic protrusions and columnar protrusions. In this production method, it is reported that the coating film having the micro-concave-convex structure can be formed by coating a coating solution in which tetrachlorosilane is dissolved in a solvent containing silicone oil as a main component. In addition, an application example is to apply a decamethylcyclopentasiloxane solution of heptadecafluorooctyltrichlorosilane by a flow coating method on the above-mentioned film with a micro-concave-convex structure, leave it to stand, and wash it off completely with ethanol. After leaving the remaining silane solution, let it dry naturally to obtain a water-repellent treated glass.

Patent Document 5 proposes to be made of a substrate and a water-repellent transparent film on the surface of the substrate. The water-repellent transparent film is composed of an inorganic oxide fine particle layer comprising inorganic oxide fine particles and a protective layer on the inorganic oxide fine particle layer ( overcoat layer), the surface of the water-repellent transparent film has a concave-convex structure, and the average height of the protrusions, the average distance between the protrusions (width of the interval), and the ratio of the average height to the aforementioned average distance between the protrusions are defined within a specific range. The surface of the convex part of the concave-convex structure has a substrate with a water-repellent transparent film with fine concave-convex.

The preparation method of the substrate in Patent Document 5, for example, proposes a preparation method including the following steps (A) and (B): (A) in methanol dispersion of alumina particles having a specific average particle length and average particle width , add tetraethoxysilane and water, make these react, thereby carry out the surface treatment of alumina microparticles, dilute with solvent to obtain surface treatment alumina microparticle dispersion liquid, apply this surface treatment alumina microparticle dispersion liquid on On the substrate, the step of hardening to form an inorganic oxide fine particle layer; (B) by making tridecafluorooctyltrimethoxysilane in alcohol using an acid catalyst, reacting with water, performing hydrolysis, and diluting with a solvent A step in which a coating solution for forming a protective layer with an adjusted concentration is applied on the inorganic oxide fine particle layer, and heated to harden to obtain a base material with a water-repellent transparent film. In addition, it is proposed to form a primer layer on the substrate before step (A), and form a binder layer on the inorganic oxide fine particle layer between step (A) and step (B). [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 11-172455 [Patent Document 2] JP-A-2005-343016 [Patent Document 3] International Publication No. 2003/039856 [Patent Document 4] Japanese Unexamined Patent Publication No. 2004-137137 [Patent Document 5] Japanese Patent Laid-Open No. 2014-124913

[Problem to be Solved by the Invention]

However, in the method of Patent Document 1, the molecular weight of the silane compound used to form the water-repellent film is small, so in the case of a compound with low alkoxysilane reactivity, the silane compound volatilizes from the water-repellent film-forming treatment solution or the water-repellent film. and disappear.

In the case of Patent Document 2 or Patent Document 5, alkoxysilanes are used as the material for forming the water-repellent film, but in this state, the reactivity is low, so water and a hydrolysis catalyst such as nitric acid or hydrochloric acid are added. The hydrolysis catalyst such as nitric acid or hydrochloric acid is also a condensation catalyst, so the hydrolysis and condensation of alkoxysilanes are carried out simultaneously in the coating liquid. Therefore, the coating solution is not necessarily stable, and insoluble solids may precipitate during storage.

Also in the case of Patent Document 3 or Patent Document 4, in the step of forming a water-repellent film, chlorosilanes having very high reactivity to moisture or a substrate are used as materials, so the stability of the coating liquid during storage is low.

The present invention has been accomplished in view of the above circumstances. The object of the present invention is to provide a chemically stable, stable storage, reusable, and easy to form a water-repellent film with good reproducibility, especially a super-water-repellent film. A composition for forming a water-repellent film. [Means to solve the problem]

As a result of careful examination to achieve the above objects, the inventors of the present invention found that the above problems can be solved by using polysilazane having a specific structure, and thus completed the present invention.

(式中，R各自表示可相同或相異可被氟取代之碳數3~20之一價烴基。R^a 及R^b 各自表示可相同或相異可被氟取代之碳數1~20之一價烴基。m為1~100之整數，n及p各自為0~100之整數。但是m、n及p之和為4~300之整數)。 〔3〕 如前述〔2〕之撥水性被膜形成用組成物，其中(b)金屬氧化物奈米粒子為藉由上述通式(1)表示之聚矽氮烷進行表面處理，藉此介隔矽原子在表面具有，可被氟取代之碳數3~20之一價烴基者。 〔4〕 如前述〔1〕~〔3〕中任一項之撥水性被膜形成用組成物，其中(b)金屬氧化物奈米粒子為二氧化矽。 〔5〕 一種撥水性被膜，其係包含(a)可被氟取代之碳數3~20之一價烴基鍵結於矽原子的聚矽氮烷及 (b)表面未處理之金屬氧化物奈米粒子、表面具有可被氟取代之碳數1~20之一價烴基之金屬氧化物奈米粒子或表面具有烷基矽基或烷氧基矽基之金屬氧化物奈米粒子。 [發明效果]That is, the present invention provides the following composition for forming a water-repellent film and a water-repellent film. [1] A composition for forming a water-repellent film, characterized by comprising the following components (a), (b) and (c), (a) a valent hydrocarbon group having 3 to 20 carbon atoms which may be substituted by fluorine Polysilazane based on silicon atoms, (b) untreated metal oxide nanoparticles on the surface, metal oxide nanoparticles with 1-20 valent hydrocarbon groups that can be substituted by fluorine on the surface, or metal oxide nanoparticles with alkanes on the surface Silica-based or alkoxysilyl-based metal oxide nanoparticles, and (c) an aprotic solvent. [2] The composition for forming a water-repellent film according to [1] above, wherein the component (a) is a polysilazane represented by the following general formula (1),

(In the formula, R each represents a valent hydrocarbon group with 3 to 20 carbons that may be the same or different and may be substituted by fluorine. R ^a and R ^b each represent a hydrocarbon group with 1 to 20 carbons that may be the same or different and may be substituted by fluorine Monovalent hydrocarbon group. m is an integer of 1 to 100, n and p are each an integer of 0 to 100. However, the sum of m, n and p is an integer of 4 to 300). [3] The composition for forming a water-repellent film according to the above-mentioned [2], wherein (b) the metal oxide nanoparticles are surface-treated with polysilazane represented by the above general formula (1), thereby mediating A silicon atom has a valent hydrocarbon group with 3 to 20 carbons that can be substituted by fluorine on its surface. [4] The composition for forming a water-repellent coating according to any one of [1] to [3] above, wherein (b) the metal oxide nanoparticles are silicon dioxide. 〔5〕 A water-repellent film comprising (a) a polysilazane with a carbon number of 3 to 20 that can be substituted by fluorine bonded to a silicon atom and (b) an untreated metal oxide nano Rice particles, metal oxide nanoparticles with a carbon number of 1-20 that can be substituted by fluorine on the surface, or metal oxide nanoparticles with alkylsilyl or alkoxysilyl groups on the surface. [Invention effect]

According to the present invention, a composition for forming a water-repellent film can be obtained which has good storage stability, is reusable, and can easily and reproducibly form a water-repellent film, especially a super-water-repellent film. Also, by using the composition of the present invention, it is possible to obtain a durable film having excellent water repellency and water drop-off property. [Mode of Implementing the Invention]

The water-repellent film-forming composition of the present invention contains the following components (a), (b) and (c), (a) A polysilazane in which a valent hydrocarbon group having 3 to 20 carbon atoms that may be substituted by fluorine is bonded to a silicon atom, (b) Metal oxide nanoparticles with untreated surface, metal oxide nanoparticles with a 1-20 carbon number hydrocarbon group that can be substituted by fluorine on the surface, or alkylsilyl or alkoxysilyl groups on the surface metal oxide nanoparticles, and (c) Aprotic solvents. Each component will be described in detail below.

＜(a) Polysilazane＞ Polysilazane refers to a polymer compound with a structure in which silicon atoms and nitrogen atoms are arranged alternately. For example, commercially available perhydropolysilazane is a polysilazane with no organic substituents on the silicon atom but with hydrogen atoms bonded to it. When a coating is formed, it is a hydrophilic material. On the other hand, the polysilazane used in the present invention can form a film with low surface free energy and exhibit water repellency because the valent hydrocarbon group having 3 to 20 carbons is bonded to the silicon atom. In addition, by substituting the above-mentioned monovalent hydrocarbon group with fluorine, the surface free energy of the film can be further reduced.

(式中，R各自表示可相同或相異可被氟取代之碳數3~20之一價烴基。R^a 及R^b 各自表示可相同或相異可被氟取代之碳數1~20之一價烴基。m為1~100之整數，n及p各自為0~100之整數。但是m、n及p之和為4~300之整數。)The polysilazane used in the present invention is preferably a polysilazane represented by the following general formula (1).

(In the formula, R each represents a valent hydrocarbon group with 3 to 20 carbons that may be the same or different and may be substituted by fluorine. R ^a and R ^b each represent a hydrocarbon group with 1 to 20 carbons that may be the same or different and may be substituted by fluorine Monovalent hydrocarbon group. m is an integer of 1 to 100, n and p are each an integer of 0 to 100. However, the sum of m, n and p is an integer of 4 to 300.)

In the above general formula (1), R each represents a valent hydrocarbon group having 3 to 20 carbons, preferably 3 to 16 carbons, more preferably 6 to 16 carbons, which may be the same or different and may be substituted by fluorine. Substituent R can include propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl Straight-chain aliphatic saturated hydrocarbon groups such as alkyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, etc.; isopropyl, isobutyl, 2-butyl, tert -Butyl, isopentyl, 2-pentyl, 3-pentyl, tert-pentyl, isohexyl, 2-ethylhexyl, isooctyl and other branched aliphatic saturated hydrocarbon groups; allyl, butene Aliphatic unsaturated hydrocarbon groups such as methallyl, pentenyl, hexenyl, octenyl, decenyl, etc.; aromatic hydrocarbon groups such as phenyl, tolyl, xylyl, mesityl, etc. ;Aralkyl such as benzyl, phenylethyl, phenylpropyl, phenylbutyl, etc.; 3,3,3-trifluoropropyl, nonafluorohexyl, tridecafluorooctyl, heptadecafluorodecyl Such as fluorine-substituted aliphatic hydrocarbon groups; pentafluorophenyl, 3,5-difluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 3-trifluoromethylphenyl, 3,5-bis(three Fluoromethyl) phenyl and other fluorine-substituted aromatic hydrocarbon groups; pentafluorophenylethyl, pentafluorophenylpropyl, pentafluorophenylbutyl, 3,4,5-trifluorophenylpropyl, 2, 4-Difluorophenylpropyl, 3,4-difluorophenylpropyl, 3,5-difluorophenylpropyl, 2-fluorophenylethyl, 2-fluorophenylpropyl, 3-fluoro Phenylethyl, 3-fluorophenylpropyl, 4-fluorophenylethyl, 4-fluorophenylpropyl, 4-(trifluoromethyl)phenylpropyl, 3,5-bis(trifluoro Fluorine-substituted aralkyl groups such as methyl) phenylpropyl groups, etc. Among them, from the viewpoint of reducing the surface free energy of the film, linear or branched aliphatic saturated monovalent hydrocarbon groups, aliphatic unsaturated monovalent hydrocarbon groups, and fluorine-substituted aliphatic saturated monovalent hydrocarbon groups are preferable.

In the above general formula (1), R ^a and R ^b each represent the same or different carbon numbers of 1 to 20 that can be substituted by fluorine, preferably 1 to 10 carbons, more preferably one of 1 to 5 carbons Valence hydrocarbon group. Examples of the substituents R ^a and R ^b include, in addition to the substituents mentioned as examples of the substituent R, alkyl groups such as methyl and ethyl groups, and aliphatic unsaturated monovalent hydrocarbon groups such as vinyl groups. When such a substituent with a small number of carbon atoms is present, the surface free energy of the film will increase, but by introducing such a substituent as necessary, the solubility and viscosity of the polysilazane can be adjusted to an appropriate range.

The polysilazane represented by the general formula (1) does not necessarily include repeating units having substituents R ^a and R ^b . However, by having such repeating units, the physical properties such as molecular weight, solubility, and viscosity of polysilazane can be adjusted to appropriate ranges.

In the above general formula (1), m is an integer of 1 to 100, preferably 4 to 50, and n and p are respectively 0 to 100, preferably an integer of 0 to 50. However, the sum of m, n and p is 4-300, preferably 4-100, more preferably 4-50. In other words, the polysilazane represented by the general formula (1) must contain a repeating unit having a substituent R. Thereby, when forming a film using the composition of the present invention, the surface free energy can be reduced.

The ratio of m, n and p is not limited, and the ratio of m/(m+n+p) is preferably 0.01~1, more preferably 0.1~1, still more preferably 0.25~1. If this ratio is less than 0.01, the influence of the substituent R on the surface free energy of the coating becomes small, and a water-repellent coating may not be obtained, or the molecular weight of polysilazane decreases and becomes a volatile component, and has the properties of a coating. Unsettled situation.

Moreover, the weight average molecular weight of polystyrene conversion measured by the gel permeation chromatography (henceforth "GPC") of a polysilazane 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 is preferably 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% by mass, the film becomes too thin and sufficient water repellency may not be obtained, and if it exceeds 50% by mass, the viscosity of the composition may become too high. Also, as described later, when preparing this composition while performing surface treatment of (b) component with (a) component, the theoretical addition amount of (a) component is calculated based on the specific surface area and addition amount of (b) component, However, in this case, it is also preferable within the above-mentioned range.

＜(b) Metal oxide nanoparticles＞ The metal oxide nanoparticles used in the present invention can be exemplified and include materials selected from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, zinc oxide, stannous oxide, cerium oxide, copper oxide, chromium oxide, cobalt oxide, iron oxide Nanoparticles of one or more metal oxides such as manganese oxide and nickel oxide. Among them, nanoparticles containing one or more metal oxides selected from silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, zinc oxide, stannous oxide, and cerium oxide are particularly preferred. It is fine particle containing silica, alumina, titania, zirconia. It is best to use fumed silica which is composed of essentially only microparticles of silica.

The average primary particle diameter of the metal oxide nanoparticles is preferably 5-200 nm in diameter, more preferably 10-150 nm in diameter, and more preferably 10-50 nm in diameter. If the particle size is less than 5 nm in diameter, effective unevenness may not be obtained. On the other hand, if the particle size exceeds 200 nm, the transparency of the film may be impaired. In addition, in the present invention, the value of the average primary particle diameter is a value measured by a scanning electron microscope (SEM).

In the case of fumed silica, the average primary particle size is related to the value of the specific surface area that can be measured by the BET method. For example, when the ^specific surface area is 50m ² /g, the average primary particle size is about 30nm; when the specific surface area is 200m ² /g, the average primary particle size is about 12nm; is about 7nm. When fumed silica is used, the specific surface area is preferably from 30 to 500 m ² /g, more preferably from 50 to 350 m ² /g.

(b) In addition to untreated metal oxide nanoparticles on the surface, metal oxide nanoparticles that have been pre-hydrophobized and have a valent hydrocarbon group with a carbon number of 1 to 20 that can be replaced by fluorine on the surface can also be used. . Metal oxide nanoparticles that have been hydrophobized in advance, for example, commercially available metal oxide nanoparticles such as AEROSILR805, AEROXIDET805, AEROXIDENKT90, AEROXIDEAluC805 (manufactured by AEROSIL Japan), etc., can be used, and formazan is introduced into the surface. Base, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl Alkyl, etc., having 1 to 20 carbon atoms, preferably 1 to 10, or the same substituents as described for R ^a and R ^b of the compound of formula (1), or, trade names AEROSILR972, AEROSILR974, AEROSILR976, AEROSILRX50, AEROSILRX200, AEROSILRX300, AEROSILR812 (manufactured by AEROSIL Japan), HDKH15, HDKH20, HDKH30 (manufactured by aws-silicone), dialkylsilyl, trimethylsilyl, trimethylsilyl, etc. The carbon number of ethylsilyl, tert-butyldimethylsilyl, triisobutylsilyl, triisopropylsilyl, etc. is preferably 1-6, more preferably 1-3 trialkyl groups Silicon base for surface treatment.

Moreover, as (b) component, the metal oxide nanoparticle which exists the alkoxy silicon group in the surface of a metal oxide nanoparticle can be used. When there are alkoxysilyl groups on the surface of the metal oxide nanoparticles, the alkoxysilyl groups on the surface of the metal oxide nanoparticles react with the polysilazane of the above-mentioned component (a) through hydrolysis and condensation to form a covalent key, so the durability of the coating becomes high.

The alkoxysilyl group includes the carbon number of the alkyl group of the alkoxy group, preferably 1-6, more preferably 1-3, specifically, trimethoxysilyl, triethoxysilyl , Tripropoxysilyl, Triisopropoxysilyl, Diisopropoxymethoxysilyl, Dimethoxyisopropoxysilyl, etc. Trialkoxysilyl; Dimethoxy Dialkoxysilyl groups such as methylsilyl and diethoxymethylsilyl; methoxydimethylsilyl, ethoxydimethylsilyl, isopropoxydimethylsilyl, Monoalkoxysilyl such as methoxydiethylsilyl, methoxydipropylsilyl, methoxydiisopropylsilyl, etc.

There are various methods for introducing alkoxysilyl groups onto the surface of metal oxide nanoparticles, preferably by reacting hydroxyl groups on the surface of untreated metal oxide nanoparticles with an alkoxysilylating agent. method. Alkoxysilylating agents, such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane and other alkoxysilanes or tetramethoxysilane oligo Alkoxysilane oligomers such as polymers, tetraethoxysilane oligomers, methyltrimethoxysilane oligomers, etc.; chlorotrimethoxysilane, chlorotriethoxysilane, chlorodimethoxymethyl Alkoxyhalosilanes such as silane and chlorodiethoxymethylsilane; alkoxysilazanes such as trimethoxysilyldimethylamine and trimethoxysilyldiethylamine; 1-trimethylsilane Oxysiloxy-1-methoxypropene, 1-trimethoxysiloxy-1-ethoxypropene, 1-trimethoxysiloxy-1-butoxypropene, 1-trimethoxy Siloxy-1-methoxy-2-methylpropene, 1-triethoxysilyloxy-1-ethoxypropene, 1-dimethoxymethylsilyloxy-1-methoxy Propylene, 1-dimethoxymethylsilyloxy-1-ethoxypropene, 1-dimethoxymethylsilyloxy-1-octyloxypropene, 1-diethoxymethylsilyloxy Base-1-methoxypropene, 1-diethoxymethylsilyloxy-1-ethoxypropene, 1-methoxydimethylsilyloxy-1-methoxypropene, 1-methyl Alkoxysilicone acetal (ketene acetal) such as oxydimethylsiloxy-1-ethoxypropylene, etc. Among them, alkoxysilicone acetal is a neutral alkoxysilylating agent, and its by-products are easy to remove, so it is preferable.

The introduction amount of the alkoxysilyl group is preferably 0.1 when the saturation introduction amount of the metal oxide nanoparticles used as component (b) is 1 from the viewpoint of the dispersibility of the metal oxide nanoparticles. ~1, more preferably 0.3~1, more preferably 0.5~1. In order to obtain the saturated introduction amount of the alkoxysilyl group, for example, the untreated metal oxide nanoparticles on the surface can be mixed with the above-mentioned alkoxysilylating agent in a certain ratio, and the alkoxysilylating agent can be obtained by gas chromatography. The consumption (or remaining amount) of the oxysilylating agent is determined. Regardless of whether the alkoxysilylating agent is in contact with the metal oxide nanoparticles, the amount of the alkoxysilyl group that will not be consumed is the saturated amount.

When using the above-mentioned alkoxysilylation agent to alkoxysilylate the surface of metal oxide nanoparticles, if the alkoxysilylation agent is mixed with the metal oxide nanoparticle in the presence or absence of a solvent, The rice particles are just in contact. The solvent that can be used is not particularly limited as long as it is an aprotic solvent that does not react with the alkoxysilylation agent. For example, hexane, heptane, octane, isooctane, nonane, decane, etc. Hydrocarbon solvents such as alkanes, toluene, xylene, mesitylene, etc.; hydrocarbon mixed solvents such as isoparaffin-based solvents and naphthene-based solvents; acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. Ketones; nitriles of acetonitrile, propionitrile, benzonitrile, etc.; amides of dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.; diethyl ether, dipropyl ether, diisopropyl ether, Tetrahydrofuran, cyclopentyl methyl ether, dibutyl ether, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether and other ether solvents; ethyl acetate, propyl acetate, Ester solvents such as isopropyl acetate, butyl acetate, isobutyl acetate, methoxyethyl acetate, and hexyl acetate, etc. These solvents may be used alone or in combination of two or more. Moreover, alkoxysilylation can also be performed without a solvent by using excess liquid alkoxysilylation agent.

In addition, a polymer that acts as the component (a) on the silanol remaining in the untreated metal oxide nanoparticles or the metal oxide nanoparticles having the above-mentioned monovalent hydrocarbon group, alkylsilyl group or alkoxysilyl group can be used. Silazane is used for surface treatment to introduce substituents R or, R ^a , R ^b on the surface by intervening silicon atoms. Thereby, the compatibility with the polysilazane of (a) component becomes favorable.

The compounded amount of polysilazane when surface-treating untreated metal oxide nanoparticles with polysilazane as component (a) can be calculated by the following formula (I): Covering area (minimum area covered by 1 g of polysilazane repeating unit), and the minimum addition amount of polysilazane calculated by the following formula (II) was set as a standard. However, especially when the substituent of polysilazane is bulky, surface treatment may be completed even with an addition amount smaller than the calculated minimum addition amount. In the present invention, from the viewpoint of obtaining good water-repellent properties and water-dropping properties, it is preferable to set the amount of polysilazane to be added above the minimum amount when the surface treatment of metal oxide nanoparticles is carried out with polysilazane. , more preferably at least 1.3 times, and more preferably at least 2 times.

The method of surface-treating the metal oxide nanoparticles with polysilazane is not particularly limited. It is also possible to mix the metal oxide nanoparticles with polysilazane and perform surface treatment by a known method, but the composition In the case of a compound, it is preferably carried out by dispersing the metal oxide nanoparticles in the solvent (c) described later, and then adding polysilazane and mixing them.

The blending amount of (b) component in the composition of the present invention is preferably changed according to the type of polysilazane (a) component, preferably 0.001-30% by mass of the entire composition, more preferably 0.01- 10% by mass, more preferably 0.01 to 5% by mass. If it exceeds 30% by mass, the viscosity of the composition may become too high, and the composition may not be uniform. If it is less than 0.001% by mass, the film becomes too thin, and sufficient water repellency may not be obtained.

＜(c) Aprotic solvent＞ As described later, the water-repellent film-forming composition of the present invention can be used to form a film on a substrate by various coating methods. However, to adjust the viscosity according to the coating method, a solvent is added to the composition of the present invention.

The solvent that can be used is not particularly limited if it is an aprotic solvent that does not react with the polysilazane represented by the general formula (1), for example, hexane, heptane, octane, isooctane, nonane Hydrocarbon solvents such as alkane, decane, toluene, xylene, mesitylene, etc.; hydrocarbon mixed solvents such as isoparaffin-based solvents and naphthene-based solvents; acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. Ketones; nitriles of acetonitrile, propionitrile, benzonitrile, etc.; amides of dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.; diethyl ether, dipropyl ether, diisopropyl ether, Tetrahydrofuran, cyclopentyl methyl ether, dibutyl ether, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether and other ether solvents; ethyl acetate, propyl acetate, Ester solvents such as isopropyl acetate, butyl acetate, isobutyl acetate, methoxyethyl acetate, and hexyl acetate, etc. These solvents may be used alone or in combination of two or more.

The compounding amount of the solvent of component (c) in the composition for forming a water-repellent film of the present invention can be changed arbitrarily according to the viscosity of the polysilazane of component (a), or according to the coating method or the necessary film thickness. 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 %. When it is less than 10% by mass, the viscosity of the composition becomes too high, and the solubility (dispersibility) of (a) component or (b) component may become insufficient. If it exceeds 99.9% by mass, the film becomes too thin, and sufficient water repellency may not be obtained.

＜Other ingredients＞ In the composition of the present invention, additives such as pigments, dyes, dispersants, viscosity modifiers, leveling agents, etc. or (b) components may be contained as other components in a small amount that does not impair the effects of the present invention. The other metal oxide nanoparticles do not have organic groups on the surface.

＜Composition for forming water-repellent film＞ The water-repellent film-forming composition of the present invention is a mixture of (a) component, (b) component, (c) component and other components necessary for blending, so that (a) component and (b) component are dissolved or dispersed in (c) ) In the solvent of the component, it is obtained by this. The method of mixing is optional, and mixing devices such as a stirrer and various mixers can be used, for example. Moreover, the method of performing ultrasonic irradiation is also effective.

When untreated metal oxide nanoparticles or metal oxide nanoparticles with monovalent hydrocarbon groups, alkyl silicon groups or alkoxy silicon groups on the surface are treated with polysilazane as component (a) After the surface treatment, the remaining (a) component, surface-treated metal oxide nanoparticles, and (c) component can be mixed, or a sufficient amount of (a) component can be mixed with, untreated or surface The present composition is obtained by mixing metal oxide nanoparticles having a monovalent hydrocarbon group, an alkylsilyl group, or an alkoxysilyl group with component (c), and performing surface treatment while mixing and dispersing.

The water-repellent film-forming composition of the present invention thus obtained is a uniform solution or dispersion without precipitation or gel, and is chemically stable, so as long as it is not mixed with protic compounds that decompose polysilazane such as water or methanol, There is no irreversible formation of insoluble matter and an inhomogeneous mixture. Therefore, it can be used without any change in performance over a long period of time. In addition, since polysilazane functions as a hygroscopic agent, even when a small amount of water is mixed, deterioration of the composition can be prevented.

＜Substrate＞ The polysilazane of the component (a) of the water-repellent film-forming composition of the present invention has excellent adhesion to the substrate surface, so it can be used for various substrates. For example, the water-repellent coating of the present invention can be formed by coating on substrates such as metal, resin, glass, ceramics, and composite materials thereof.

＜Coating method＞ The method of coating the water-repellent film-forming composition of the present invention must be a method in which the composition wets the substrate surface uniformly. Specific methods include, for example, a curtain coating method, a dip coating method, a curtain coating method, a spin coating method, a spray coating method, a bar coating method, and the like. Just select an appropriate coating method according to the type or shape of the base material and the necessary film thickness.

＜Water repellent film＞ After coating the water-repellent film-forming composition of the present invention on the substrate surface, the aprotic solvent of component (c) is removed, thereby obtaining the water-repellent film of the present invention in a simple manner. The method of removing the solvent is generally a method of volatilizing under normal pressure or reduced pressure. At this time, the time can also be shortened by heating.

When removing the aprotic solvent, or after removing the aprotic solvent, by allowing water to act on the surface of the film, part or all of the polysilazane can be converted into polysiloxane. It is preferable to improve the durability of the film by this operation. As a method of causing water to act, for example, it can be performed by any method such as standing still in an environment where water vapor exists at about 10 to 95% RH, or immersing in water.

The thickness of the water-repellent film of the present invention is arbitrary, and generally speaking, the average thickness is preferably 10 nm to 50 μm, more preferably 50 nm to 10 μm. When it is less than 10 nm, the film becomes too thin, and sufficient water repellency may not be obtained. When the thickness exceeds 50 μm, cracks may be generated when the solvent is removed.

The water-repellent film of the present invention has both high water-repellency and drop-off property. The index of the water repellency of the film, that is, the contact angle to water is typically 150° or more, indicating super water repellency, preferably 160° or more. In addition, the index of the fallability of water droplets, that is, the drop angle of water (the angle at which the droplets start to fall) varies depending on the size of the water droplets, but typically it is 5° or less, preferably 3° or less, and more preferably 1°. ° below. In addition, it is preferable to use a coating having a contact angle of 160° or more because the water falling speed is high.

[Example]

Synthesis examples, examples of the present invention, and comparative examples are described below, but the present invention is not limited to these examples.

[Synthesis Example 1] Synthesis of Octylpolysilazane Replace the inside of a 1L four-necked glass flask equipped with a stirrer, a gas supply tube, a thermometer, and a reflux cooler with nitrogen, and inject octyl while feeding nitrogen into the open end of the upper part of the reflux cooler to avoid mixing outside air. Stir 309.6g (1.25 moles) of trichlorosilane and 500mL of toluene to obtain a uniform solution. Ammonia gas was delivered to the solution at a rate of about 0.62 moles per hour through the feed tube while stirring the contents at room temperature. While preventing the temperature of the content from exceeding 40°C for cooling, the feeding of ammonia was continued for 7.1 hours. Then, the feeding of ammonia was stopped, and nitrogen gas was blown in at a rate of 0.5 L/min through the feeding pipe for 6 hours to flush the remaining ammonia gas. The resulting white solid was filtered through a membrane filter to obtain a colorless and transparent solution. This solution was concentrated under reduced pressure and vacuum-dried at room temperature to obtain 142.8 g of a cloudy oily octyl polysilazane.

The polystyrene conversion molecular weight obtained by GPC was 2420 in weight average molecular weight, and 1900 in number average molecular weight. In addition, the measurement conditions of GPC are as follows. [GPC conditions] Device: Prominence GPC system (manufactured by Shimadzu Corporation) Column: LF-404 (4.6mm×250mm) (manufactured by Shodex)×2 Eluent: Tetrahydrofuran (THF) Flow rate: 0.35ml/min Detector: RI Column thermostat temperature: 40°C Standard material: polystyrene

After measuring the infrared absorption spectrum (FT-IR), it was observed at 893 cm ^-1 (Si-N-Si), 1152 cm ^-1 (NH), 2853 cm ^-1 , 2920 cm ^-1 (CH), 3384 cm ^-1 (NH) Absorption, supports the discussion of octylpolysilazane for the purpose of formation.

[Synthesis Example 2] Synthesis of Decylpolysilazane Decylpolysilazane as a white oil was obtained in the same manner as in Synthesis Example 1, except that 344.6 g (1.25 moles) of decyltrichlorosilane was used instead of octyltrichlorosilane. The weight average molecular weight obtained by GPC was 2970, and the number average molecular weight was 2230.

[Synthesis Example 3] Synthesis of Hexylpolysilazane Hexylpolysilazane as a white oil was obtained in the same manner as in Synthesis Example 1, except that 272.5 g (1.25 moles) of hexyltrichlorosilane was used instead of octyltrichlorosilane, and toluene was set to 750 mL. The weight average molecular weight obtained by GPC was 1250, and the number average molecular weight was 1130.

[Synthesis Example 4] Synthesis of Propylpolysilazane Propylpolysilazane as a white oil was obtained in the same manner as in Synthesis Example 1, except that 221.9 g (1.25 moles) of propyltrichlorosilane was used instead of octyltrichlorosilane and 1125 mL of cyclopentylmethyl ether was used instead of toluene. The weight average molecular weight obtained by GPC was 890, and the number average molecular weight was 770.

[Synthesis Example 5] Synthesis of (Tridecafluorooctyl)(trifluoropropyl)polysilazane Replace the inside of a 300mL four-necked glass flask equipped with a stirrer, a gas delivery tube, a thermometer, and a reflux cooler with nitrogen, and inject nitrogen gas into the upper open end of the reflux cooler to avoid mixing outside air. ,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyltrichlorosilane 54.2g (112.5mmol) and 3,3,3-trifluoropropyl Stir 8.68 g (37.5 mmol) of trichlorosilane and 135 mL of cyclopentyl methyl ether to obtain a uniform solution. While stirring the contents, ammonia gas was fed into the solution at a rate of about 124 moles per hour through the feed tube at room temperature. Cool the contents while preventing the temperature of the contents from exceeding 40°C, while continuing to feed the ammonia for 4.8 hours. Then, the feeding of ammonia was stopped, and nitrogen gas was blown in at a rate of 0.15 L/min through the feeding pipe for 6 hours to flush the remaining ammonia gas. The resulting white solid was filtered with a membrane filter to obtain a colorless and transparent solution. This solution was concentrated under reduced pressure and vacuum-dried at room temperature to obtain 39.3 g of a cloudy oily substance.

The polystyrene-equivalent molecular weight obtained by GPC was 2750 in weight average molecular weight, and 2500 in number average molecular weight. When measuring infrared absorption spectrum (FT-IR), at 898cm ^-1 (Si-N-Si), 1141cm ^-1 (CF), 1183cm ^-1 (NH), 2946cm ^-1 (CH), 3394cm ^-1 (NH) Absorption was observed, confirming the formation of the target (tridecafluorooctyl)(trifluoropropyl)polysilazane.

[Synthesis Example 6] Synthesis of Tridecafluorooctylpolysilazane Replace the inside of a 200mL four-necked glass flask equipped with a stirrer, a gas supply tube, a thermometer, and a reflux cooler with nitrogen, and feed nitrogen gas into the upper open end of the reflux cooler to avoid mixing outside air. 3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyltrichlorosilane 48.2g (100mmol) and m-xylene hexafluoride (m‐ xylenehexafluoride) 90mL, stirred to obtain a uniform solution. While stirring the contents, ammonia gas was fed into the solution at a rate of about 79 moles per hour through the feed tube at room temperature. While preventing the temperature of the content from exceeding 40°C for cooling, the feeding of ammonia was continued for 5.5 hours. Then, the feeding of ammonia was stopped, and nitrogen gas was blown in at a rate of 0.15 L/min through the feeding pipe for 2 hours to flush the remaining ammonia gas. The resulting white solid was filtered with a membrane filter to obtain a colorless and transparent solution. This solution was concentrated under reduced pressure and vacuum-dried at room temperature to obtain 25.4 g of a cloudy oily substance.

The polystyrene-equivalent molecular weight obtained by GPC was 2840 in weight average molecular weight, and 2680 in number average molecular weight. When measuring infrared absorption spectrum (FT-IR), at 932cm ^-1 (Si-N-Si), 1141cm ^-1 (CF), 1182cm ^-1 (NH), 2945cm ^-1 (CH), 3394cm ^-1 (NH) Absorption was observed, and it was confirmed that the target tridecafluorooctylpolysilazane was produced.

[Synthesis Example 7] Synthesis of Hexyl(Dimethyl)polysilazane Replace the inside of a 500mL four-necked glass flask equipped with a stirrer, a gas delivery tube, a thermometer, and a reflux cooler with nitrogen, and inject nitrogen gas into the open end of the upper part of the reflux cooler to avoid mixing with external air. 32.9 g (150 mmol) of silane, 6.5 g (50 mmol) of dimethyldichlorosilane, and 165 mL of toluene as a solvent were stirred to obtain a uniform solution. While stirring the contents, ammonia gas was fed into the solution at a rate of about 150 moles per hour through the feed tube at room temperature. While cooling while preventing the temperature of the content from exceeding 40°C, continue feeding ammonia for 6 hours. Then, the feeding of ammonia was stopped, and nitrogen gas was blown in at a rate of 0.15 L/min through the feeding pipe for 2 hours to flush the remaining ammonia gas. The resulting white solid was filtered with a membrane filter to obtain a colorless and transparent solution. This solution was concentrated under reduced pressure and vacuum-dried at room temperature to obtain 18.9 g of a colorless oily substance.

The polystyrene conversion molecular weight obtained by GPC was 1574 in weight average molecular weight, and 1144 in number average molecular weight. When measuring infrared absorption spectrum (FT-IR), absorption was observed at 900cm ^-1 , 1153 cm ^-1 , (Si-N-Si), 1459cm ^-1 , 2853cm ^-1 (CH), 3389cm ^-1 (NH), Confirm the purpose of polysilazane formation.

[Synthesis Example 8] Preparation of silica particle dispersion liquid having trimethoxysilyl groups on the surface In a glass container with a resin lid, weigh fumed silica (specific surface area 205m ² /g, trade name reolosil QS- 102, manufactured by Tosoh) 5.00g, add 56.25g of cyclopentyl methyl ether, 1.25g of 1-trimethoxysilyloxy-1-ethoxypropene, and irradiate ultrasonic waves for 1 hour while shaking sometimes, so that the smoked two Silicon oxide is evenly dispersed. A white translucent and stable dispersion was obtained. The dispersion was measured by GC, and it was found that 1-trimethoxysilyloxy-1-ethoxypropene disappeared and no volatile compound with trimethoxysilyl was formed. , it is judged that trimethoxysilyl groups are introduced into the surface of silica.

[Example 1] In a glass container with a resin lid, 2 g of fumed silica (specific surface area 205 m ² /g, trade name reolosil QS-102, manufactured by Tosoh) was weighed, and 77 g of cyclopentyl methyl ether, 20g of dipropylene glycol dimethyl ether was irradiated with ultrasonic waves for 30 minutes to evenly disperse fumed silicon dioxide. 1 g of the octylpolysilazane obtained in Synthesis Example 1 was added, followed by ultrasonic irradiation for 15 minutes, thereby obtaining a white translucent water-repellent film-forming composition. This composition is stable for more than one month at room temperature under airtight conditions.

Next, this composition was used as a coating solution, and was coated on a soda lime glass substrate (manufactured by Matsunami Glass) using a coating bar so that the film thickness after drying was about 1 μm. Then, the solvent was evaporated by making the coating film in an environment of 25° C. and 50% RH to form a water-repellent coating on the glass substrate.

＜Evaluation of water-repellent film＞ For the formed water-repellent film, use a contact angle meter (DMs-401) manufactured by Kyowa Interface Science to measure the contact angle (10μL) and drop angle of pure water on the film surface under the conditions of 25°C and 50%RH (20 μL), the contact angle was 163° and the drop angle was 1°. It was found that a water-repellent film exhibiting super water-repellency and extremely good water droplet drop-off property was formed.

Next, after immersing the soda-lime glass substrate with the water-repellent film formed above in pure water at 25°C for 1 hour, the contact angle and drop angle were measured. The measured contact angle was 163° and the drop angle was 1°.

In addition, this glass substrate was washed with warm water for 1 hour using a dish dryer NP-TCM4 (manufactured by Panasonic), and when the contact angle and drop angle were measured, the contact angle was 163° and the drop angle was 1°. . No deterioration in performance after washing with water was observed, and it was judged that a durable water-repellent film was formed. Table 1 shows the measurement results of the formulation amount, stability, film thickness, contact angle and drop angle of the composition.

[Example 2] A composition for forming a water-repellent film was obtained in the same manner as in Example 1 except that the coating film thickness obtained by the coating bar was changed to the film thickness shown in Table 1. Using the obtained composition, a water-repellent film was formed on the same glass substrate as in Example 1, and a water-repellent film exhibiting super water-repellency and extremely good water droplet dropping property was formed. The measurement results of the compounding amount, stability, film thickness, contact angle and drop angle of the composition are listed in Table 1.

[Example 3] A water-repellent film-forming composition was obtained in the same manner as in Example 1, except that the addition amounts of fumed silica and octylpolysilazane were each 1.5 g. Using the obtained composition, a water-repellent film was formed on the same glass substrate as in Example 1, and a water-repellent film exhibiting super water-repellency and extremely good water droplet dropping property was formed. The measurement results of the compounding amount, stability, film thickness, contact angle and drop angle of the composition are listed in Table 1.

[Comparative example 1] A composition for forming a water-repellent film was obtained in the same manner as in Example 1, except that the addition amounts of fumed silica and octylpolysilazane were changed as shown in Table 1. Using the obtained composition, a water-repellent film was formed on the same glass substrate as in Example 1. The measurement results of the compounding amount, stability, film thickness, contact angle and drop angle of the composition are listed in Table 1. The coating film obtained in Comparative Example 1 in which fumed silica was not added did not become super water-repellent.

[Example 4~6] A composition for forming a water-repellent film was obtained in the same manner as in Example 1, except that the types of polysilazane to be added were changed to those shown in Table 2. Using the obtained composition, a water-repellent film was formed on the same glass substrate as in Example 1, and all of them showed super water-repellency, and the water-repellent film was extremely good in droplet drop. The measurement results of compounding amount, stability, film thickness, contact angle and drop angle of the composition are listed in Table 2.

[Example 7] Hydrophobic fumed silica (specific surface area 145 m ² /g, trade name AEROSILRX200, manufactured by Japan AEROSIL Co., Ltd.) was weighed in a glass container with a resin lid. 0.9g, add 30.8g of cyclopentyl methyl ether and 8.0g of dipropylene glycol dimethyl ether, and mix for 1 minute with a self-rotating mixer to disperse the surface-modified fumed silica. 0.3 g of the octylpolysilazane obtained in Synthesis Example 1 was added, and mixed for another 5 minutes using a rotary mixer to obtain a white translucent water-repellent film-forming composition. This composition is stable for more than one month at room temperature under airtight conditions.

Next, this composition was used as a coating solution, and was coated on a soda lime glass substrate (manufactured by Matsunami Glass) using a coating bar so that the film thickness after drying was about 1 μm. Then, by making the coating film evaporate the solvent in an environment of 25° C. and 50% RH, a water-repellent coating was formed on the glass substrate.

＜Evaluation of water-repellent film＞ For the formed water-repellent film, use a contact angle meter (DMs-401) manufactured by Kyowa Interface Science to measure the contact angle (10μL) and drop angle of pure water on the film surface under the conditions of 25°C and 50%RH (20 μL), the contact angle was 163° and the drop angle was 1°. It was found that a water-repellent film exhibiting super water-repellency and extremely good water droplet drop-off property was formed.

[Example 8] A composition for forming a water-repellent film was obtained in the same manner as in Example 7 except that the added polysilazane was changed to the (tridecafluorooctyl)(trifluoropropyl)polysilazane obtained in Synthesis Example 5. Using the obtained composition, a water-repellent film was formed on the same glass substrate as in Example 7, and a water-repellent film exhibiting super water-repellency and extremely good water droplet dropping properties was formed.

[Example 9] A composition for forming a water-repellent film was obtained in the same manner as in Example 7, except that the added polysilazane was changed to tridecafluorooctylpolysilazane obtained in Synthesis Example 6, and 38.8 g of xylene hexafluoride was used as a solvent. . Using the obtained composition, a water-repellent film was formed on the same glass substrate as in Example 7, and a water-repellent film exhibiting super water-repellency and extremely good water droplet dropping property was formed.

The measurement results of the compounding amount, stability, film thickness, contact angle and drop angle of the compositions of Examples 7-9 are listed in Table 3.

[Example 10] In a glass container with a resin lid, 0.18 g of fumed silica (specific surface area 205 m ² /g, trade name reolosil QS-102, manufactured by Tosoh) was weighed, and 6.10 g of cyclopentyl methyl ether was added , 1.60g of dipropylene glycol dimethyl ether, 0.036g of 1-trimethoxysilyloxy-1-ethoxypropene, 30 minutes of ultrasonic irradiation, the introduction of trimethoxysilyl groups on the surface of silicon dioxide, so that the smoked two Silicon oxide is uniformly dispersed in the solvent. Next, a 50% by mass cyclopentyl methyl ether solution containing 0.06 g of octylpolysilazane obtained in Synthesis Example 1 was added, followed by ultrasonic irradiation for 15 minutes, thereby obtaining a translucent white water-repellent film-forming composition . This composition is stable for more than one month at room temperature under airtight conditions. The preparation method of the composition of this example is described as method A.

Next, this composition was used as a coating solution, and was coated on a soda lime glass substrate (manufactured by Matsunami Glass) using a coating bar so that the film thickness after drying was about 1 μm. Then, by making the coating film evaporate the solvent in an environment of 25° C. and 50% RH, a water-repellent coating was formed on the glass substrate.

＜Evaluation of water-repellent film＞ For the formed water-repellent film, use a contact angle meter (DMs-401) manufactured by Kyowa Interface Science to measure the contact angle (10μL) and drop angle of pure water on the film surface under the conditions of 25°C and 50%RH (20 μL), the contact angle was 161° and the drop angle was 1°. It was found that a water-repellent film exhibiting super water-repellency and extremely good water droplet drop-off property was formed.

In addition, this glass substrate was washed with warm water for 1 hour using a dish dryer NP-TCM4 (manufactured by Panasonic), and the contact angle and drop angle were measured. The contact angle was 162° and the drop angle was 1°. No degradation in performance due to washing with water was observed, and it was judged that a durable water-repellent film was formed.

In addition, after measuring the total light transmittance and haze of the soda-lime glass substrate with the water-repellent film formed by the above-mentioned method using a haze meter (HZ-V3) of Suga Testing Corporation, the total light transmittance was 92.7%, and the haze was 92.7%. It was 0.8%, showing a film with high transparency. The compounding amount of the composition, and the measurement results of contact angle, drop angle, total light transmittance, and haze are listed in Table 1.

[Example 11~13] A water-repellent film-forming composition was obtained by method A in the same manner as in Example 10 except that the compounding amount of the composition was changed as shown in Table 4. Using the obtained composition, a water-repellent film was formed on the same glass substrate as in Example 10, and a water-repellent film exhibiting super water-repellency and extremely good water droplet dropping property was formed. The blending amount of the composition, and the measurement results of contact angle, drop angle, total light transmittance, and haze are listed in Table 4.

[Comparative example 2] Without adding fumed silica and 1-trimethoxysiloxy-1-ethoxypropene, a water-repellent film-forming composition was obtained with the composition described in Table 4. Using the obtained composition, a water-repellent film was formed on the same glass substrate as in Example 10. Table 4 records the blended amount of the composition, the contact angle, and the measurement results of the drop angle. 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 組成物中之環戊基甲醚全量

※1 The total amount of cyclopentyl methyl ether in the composition

[Example 14] In a glass container with a resin lid, weigh 1.50 g of the silica particle dispersion having a trimethoxysilyl group obtained in Synthesis Example 8, add 4.62 g of cyclopentyl methyl ether, 1.02 g of dipropylene glycol dimethyl ether, The 25% by mass dipropylene glycol dimethyl ether solution containing 0.06 g of octylpolysilazane obtained in Synthesis Example 1 was mixed for 1 minute to obtain a white translucent water-repellent film-forming composition. This composition is stable for more than one month at room temperature under airtight conditions. The preparation method of the composition of this example is described as method B.

Using the obtained composition, a water-repellent film was formed on the same glass substrate as in Example 10, and a water-repellent film exhibiting super water-repellency and extremely good water droplet dropping property was formed. The blending amount of the composition, and the measurement results of contact angle, drop angle, total light transmittance, and haze are listed in Table 5.

[Example 15] A water-repellent film-forming composition was obtained by method B in the same manner as in Example 14, except that the compounding amount of the composition was changed as shown in Table 5. Using the obtained composition, a water-repellent coating was formed on the same glass substrate as in Example 14, and a water-repellent coating exhibiting super water-repellency and extremely good water droplet dropping properties was formed. The blending amount of the composition, and the measurement results of contact angle, drop angle, total light transmittance, and haze are listed in Table 5.

※2 作為合成例8所使用的燻製二氧化矽與1-三甲氧基矽氧基-1-乙氧基丙烯之調配量 ※3 組成物中之二丙二醇二甲醚全量

※2 The blending amount of fumed silica and 1-trimethoxysiloxy-1-ethoxypropene used in Synthesis Example 8. ※3 The total amount of dipropylene glycol dimethyl ether in the composition

[Example 16~18] The type of polysilazane to be added and the compounding amount of the composition were changed as shown in Table 6. In the same manner as in Example 10 or Example 14, a composition for forming a water-repellent film was obtained by method A or method B. Using the obtained composition, a water-repellent film was formed on the same glass substrate as in Example 1, and a water-repellent film exhibiting super water-repellency and extremely good water droplet dropping property was formed. The blending amount of the composition and the measurement results of contact angle, drop angle, total light transmittance, and haze are shown in Table 6.

※1 組成物中之環戊基甲醚全量 ※3 組成物中之二丙二醇二甲醚全量

※1 The total amount of cyclopentyl methyl ether in the composition ※3 The total amount of dipropylene glycol dimethyl ether in the composition

Claims (4)

A composition for forming a water-repellent film, characterized by comprising the following components (a), (b) and (c), (a) a polysilazane represented by the following general formula (1),

(In the formula, R each represent a valent hydrocarbon group with 3 to 20 carbons that may be the same or different and may be substituted by fluorine, R ^a and R ^b each represent a hydrocarbon group with 1 to 20 carbons that may be the same or different and may be substituted by fluorine Monovalent hydrocarbon group, m is an integer from 1 to 100, n and p are each an integer from 0 to 100, but the sum of m, n and p is an integer from 4 to 300), (b) untreated metal oxide on the surface Rice particles, metal oxide nanoparticles with a 1-20 valent hydrocarbon group that can be substituted by fluorine on the surface, or metal oxide nanoparticles with alkylsilyl or alkoxysilyl groups on the surface, and (c ) Aprotic solvents. The composition for forming a water-repellent film according to claim 1, wherein (b) the metal oxide nanoparticles are surface-treated with polysilazane represented by the above general formula (1), and have silicon atoms on the surface, which can A valent hydrocarbon group with 3 to 20 carbons substituted by fluorine. The composition for forming a water-repellent film according to claim 1 or 2, wherein (b) the metal oxide nanoparticles are silicon dioxide. A water-repellent film comprising (a) polysilazane represented by the following general formula (1),

(In the formula, R each represent a valent hydrocarbon group with 3 to 20 carbons that may be the same or different and may be substituted by fluorine, R ^a and R ^b each represent a hydrocarbon group with 1 to 20 carbons that may be the same or different and may be substituted by fluorine Monovalent hydrocarbon group, m is an integer from 1 to 100, n and p are each an integer from 0 to 100, but the sum of m, n and p is an integer from 4 to 300) and (b) untreated metal oxide nano Rice particles, metal oxide nanoparticles with a carbon number of 1-20 that can be substituted by fluorine on the surface, or metal oxide nanoparticles with alkylsilyl or alkoxysilyl groups on the surface.