JP2018172566A - Anti-fogging coating film and coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel coating film excellent in anti-fogging property, anti-fogging persistence and a deposition property.SOLUTION: There is provided a coating film containing metal oxide (A) and a hydrophilic compound (B) and having element concentration ratio of a C element and a metal element obtained from C1s spectrum and metal (M) spectrum derived from metal oxide in an element analysis by XPS of a surface (C1s/M) of 10 or more. There is provided a coating film, in which water contact angle of the coating film is 40° or more and water contact angle change degree may be 1 to 3. There is provided a coating film, in which relative element concentration of the C element obtained from C1s spectrum derived from a carbon-oxygen bond and/or a carbon-nitrogen bond in the element analysis by XPS of the surface may be 5 atom% or more. There is provided a coating film, in which the metal oxide may be colloidal silica.EFFECT: The coating film can be used especially preferably as an anti-fogging coating film, and a coating film for automobile exterior components.SELECTED DRAWING: None

Description

  The present invention relates to an antifogging coating film and a coating composition. The present invention particularly relates to an antifogging coating film excellent in thick film forming properties, antifogging properties, and antifogging durability, and a coating composition for producing the same.

As an alternative to a glass plate, resin molded bodies are widely used from the viewpoint of weight reduction and moldability. As applications, it is used in a wide range of fields such as automobile parts, home appliance parts, housings, containers, films, sheets and the like. In particular, transparent plastics are used for various windows, optical lenses, mirrors, glasses, goggles, sound insulation walls, traffic light lenses, headlamp lenses, curve mirrors, windshields, nameplates, and the like. However, a resin base material such as plastic may cause condensation on the surface of the base material when one surface of the base material becomes lower than the dew point temperature due to a temperature / humidity difference from the outside air or when a sudden temperature / humidity change occurs. In some cases, fine water droplets adhere to the surface and scatter transmitted light. In such a case, the resin molded body is impaired in transparency and so-called fogging occurs.
The following proposals have been made as a method for preventing this fogging.
(1) A method of producing a coating film of a water-absorbing compound on the substrate surface.
(2) A method of making a substrate surface hydrophilic by preparing a coating film of a hydrophilic compound such as a surfactant on the substrate surface.

Specifically, as a method of (1), Patent Document 1 has a water-absorbing crosslinked resin layer made of a cured epoxide resin or a urethane resin, and the water-absorbing layer contains metal oxide fine particles. Articles have been proposed. Further, Patent Document 2 proposes an antifogging article having a water absorbing layer containing a cured epoxy resin and a polyoxyethylene alkyl ether surfactant.
However, in these methods, the anti-fogging property can be maintained up to a certain level, but fogging occurs when water having a water absorption capacity or more is aggregated and adhered to the article. Therefore, there is a disadvantage that it is necessary to increase the film thickness in order to develop high anti-fogging durability.

As the method (2), Patent Document 3 and Patent Document 4 disclose hydrophilic and antifouling coating films characterized in that the coating film surface is colloidal silica. Specifically, Patent Document 3 and Patent Document 4 disclose an antifouling coating film containing colloidal silica and a nonionic surfactant. However, this example is characterized in that colloidal silica is unevenly distributed on the outermost surface of the coating film. Therefore, although it is excellent in the initial hydrophilicity and antifogging property, the antifogging property may be lowered due to the adsorption of foreign matters to the surface of the coating film in a severe environment such as a high temperature and high humidity environment.
Furthermore, in the case of a coating film containing a lot of colloidal silica, the difference in thermal expansion coefficient between the resin substrate and the coating film is large. Therefore, when the film thickness of the coating film exceeds 1 μm, there is a disadvantage that appearance defects such as cracks occur after the film formation.

International Publication No. 2012/161330 International Publication No. 2015/008672 Patent No. 4812902 International Publication No. 2010/104146

  This invention makes it a subject to provide the novel coating film which is not in a prior art. In view of the above-mentioned disadvantages of the prior art, the present invention preferably has good film formability even when the film thickness exceeds 1 μm, has excellent antifogging properties, and prevents the film even when exposed to high temperature and high humidity. The objective is to provide a cloudy film that is sustainable.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.
That is, various aspects of the present invention are as follows.
[1]
Element concentration ratio of C element and metal element obtained from C1s spectrum and metal oxide-derived metal (M) spectrum in elemental analysis by XPS, including metal oxide (A) and hydrophilic compound (B) The coating film whose (C1s / M) is 10 or more.
[2]
The coating film according to item [1], wherein the water contact angle value is 40 ° or more and the water contact angle change value is 1 or more and 3 or less.
[3]
In the above [1] or [2], the relative element concentration of C element obtained from C1s spectrum derived from carbon-oxygen bond and / or carbon-nitrogen bond in elemental analysis by XPS on the surface is 5 atomic% or more. Coating film.
[4]
The coating film according to any one of [1] to [3], wherein the metal oxide (A) is colloidal silica.
[5]
Any one of the items [1] to [4], wherein the hydrophilic compound (B) is bonded to the surface of the metal oxide through a non-covalent bond and / or a covalent bond. Coating film according to.
[6]
The coating film according to any one of [1] to [5] above, further comprising an isocyanate compound (C).
[7]
The coating film according to any one of [1] to [6] above, further comprising polymer particles (D).
[8]
[1] to [7] containing a metal oxide (A), a hydrophilic compound (B), and, optionally, an isocyanate compound (C) and / or polymer particles (D) and / or water. The coating composition for manufacturing the coating film of any one of claim | items.

  According to the present invention, a novel coating film that does not exist in the prior art is provided. In addition, according to the present invention, the film preferably has excellent antifogging properties, and even when the film thickness exceeds 1 μm, the film formability is good, even when exposed to harsh environments such as high temperature and high humidity. It is possible to provide a coating film that maintains antifogging properties.

  Hereinafter, a mode for carrying out the present invention (hereinafter abbreviated as “embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

  Each component of the present invention will be described.

The coating film according to one embodiment is formed by, for example, applying a coating composition (may be abbreviated as “water dispersion”) dispersed in a solvent such as water on a substrate and drying. The Therefore, basically, the coating composition and the coating composition have the same component composition and ratio except for the solvent. That is, unless otherwise specified, the coating film according to the present invention has the characteristics and quantity ratios possessed by the component groups of the coating composition described below. Therefore, below, it demonstrates centering around the structure of a coating composition.
The coating composition which concerns on one Embodiment contains (A) component: Metal oxide and (B) component: A hydrophilic compound.

Component (A): Metal oxide As the metal oxide used for the component (A), from the viewpoint of interaction with the component (B), for example, silicon dioxide, aluminum oxide, antimony oxide, titanium oxide, indium oxide, Tin oxide, zirconium oxide, lead oxide, iron oxide, calcium silicate, magnesium oxide, niobium oxide, cerium oxide, and the like can be used. Of these, silicon dioxide (silica), aluminum oxide (alumina), antimony oxide, and complex oxides thereof having a large surface hydroxyl group are preferable from the viewpoint of the strength of interaction. In addition, you may use 2 or more types of the metal oxide mentioned above together as (A) component.

  Furthermore, as a metal oxide used for the component (A), a compound that expresses photocatalytic activity and / or hydrophilicity by light irradiation (hereinafter, simply referred to as “photocatalyst”) from the viewpoint of imparting antifouling properties. ) May be used. By using a compound that exhibits photocatalytic activity by light irradiation as the component (A), the surface of the coating film formed from the coating composition can exhibit excellent decomposition activity and contamination resistance of the contaminating organic substance. In the present specification, the “hydrophilicity” of the coating film means that the saturated water contact angle of water (23 ° C.) with respect to the surface of the measurement object is preferably 60 ° or less. The method for measuring the saturated water contact angle and the water contact angle will be described later in Examples. Here, the “compound that exhibits hydrophilicity by light irradiation” is distinguished from the hydrophilic compound of component (B) that has hydrophilicity.

As a photocatalyst, more _{specifically, TiO 2, ZnO, SrTiO 3} , BaTiO 3, BaTiO 4, BaTi 4 O 9, K 2 NbO 3, Nb 2 O 5, Fe 2 O 3, Ta 2 O 5, K 3 Ta ₃ Si ₂ O ₃ , WO ₃ , SnO ₂ , Bi ₂ O ₃ , BiVO ₄ , NiO, Cu ₂ O, RuO ₂ , CeO _{2 and the} like can be used. Further, a layered oxide having at least one element selected from Ti, Nb, Ta, and V as a photocatalyst (for example, JP-A-62-274452, JP-A-2-172535, JP-A-7- No. 24329, JP-A-8-89799, JP-A-8-89800, JP-A-8-89804, JP-A-8-198061, JP-A-9-248465, JP-A-10-99694. JP, 10-244165, etc.) can be used. Among these photocatalysts, TiO ₂ (titanium oxide) is preferable because it is harmless and has excellent chemical stability. As the titanium oxide, any of anatase type, rutile type, and brookite type can be used.

  Moreover, as a metal oxide used for the component (A), a conductive metal oxide can be used from the viewpoint of expressing antistatic performance of a coating film formed from the coating composition. As the conductive metal oxide, for example, tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), tin oxide, zinc oxide, or the like can be used.

  The component (A) is used as a raw material for the coating composition, for example, in the form of powder, dispersion, sol and the like. Here, the dispersion or sol means that the component (A) is a primary particle and a concentration of 0.01 to 80% by mass, preferably 0.1 to 50% by mass in water and / or a hydrophilic organic solvent. Means dispersed as secondary particles. Examples of the hydrophilic organic solvent include alcohols such as ethylene glycol, butyl cellosolve, n-propanol, isopropanol, n-butanol, ethanol and methanol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and ethers such as tetrahydrofuran and dioxane. Amides such as dimethylacetamide and dimethylformamide, dimethyl sulfoxide, nitrobenzene, N-methylpyrrolidone and the like, and a mixture of two or more of these.

  Number average particle size of component (A) observed in powder, dispersion or sol (may be a mixture of primary particles and secondary particles, or only primary particles or secondary particles May be 1 nm to 400 nm, more preferably 1 nm to 100 nm, still more preferably 3 nm to 80 nm, and particularly preferably 4 nm to 50 nm. The number average particle diameter in the specific range here is usually maintained even in the formed coating film. The number average particle diameter of the component (A) can contribute to the optical properties and the like of the coating film formed using the resulting coating composition. In particular, by setting the number average particle diameter to 100 nm or less, the transparency of the obtained coating film can be greatly improved. In addition, the number average particle diameter (simply abbreviated as “particle diameter”) in the description of the component (A) is a value measured according to the method of Examples described later.

  In one embodiment, the metal oxide (A) is preferably colloidal silica from the viewpoint of handleability. Colloidal silica may be prepared by a sol-gel method, or a commercially available product may be used. For preparation by the sol-gel method, Werner Stober et al; Colloid and Interface Sci. , 26, 62-69 (1968), Rickey D .; Badley et al; Lang muir 6, 792-801 (1990), Color Material Association Journal, 61 [9] 488-493 (1988), and the like. Colloidal silica is a dispersion of water or a water-soluble solvent of silica having silicon dioxide as a basic unit. The number average particle diameter of colloidal silica is 1 to 400 nm, preferably 1 to 100 nm, and more preferably 4 to 50 nm. When the number average particle diameter is 1 nm or more, the storage stability of the coating composition tends to be good. Further, when the number average particle diameter is 400 nm or less, the transparency tends to be good.

  Colloidal silica having a number average particle diameter in the above range can be used in the state of an aqueous dispersion, whether it is acidic or basic. The liquid property can be appropriately selected according to the stable region of the hydrophilic compound (B) to be mixed. When both are non-covalently bonded, the non-covalent bond between the colloidal silica and the hydrophilic compound becomes strong, and therefore an acidic region having a pH of 7 or less is preferable. Examples of acidic colloidal silica using water as a dispersion medium include, as commercial products, Snowtex (registered trademark) -OXS, Snowtex-OS, Snowtex-O, Snowtex-OL, and Snowtex manufactured by Nissan Chemical Industries, Ltd. -OYL, Asahi Denka Kogyo Co., Ltd. Adelite (registered trademark) AT-20Q, Clariant Japan K.K. clebosol (registered trademark) 20H12, clebosol 30CAL25 and the like can be used.

  Examples of basic colloidal silica include silica stabilized by the addition of alkali metal ions, ammonium ions, and amines. For example, SNOWTEX-20, SNOWTEX-30, SNOWTEX-C30, SNOWTEX-CM40, SNOWTEX-N, SNOWTEX-N30, SNOWTEX-K, Snow, manufactured by Nissan Chemical Industries, Ltd. Tex-XL, Snowtex-YL, Snowtex-ZL, Snowtex PS-M, Snowtex PS-L, etc. can be used. Alternatively, Adelite AT-20, Adelite AT-30, Adelite AT-20N, Adelite AT-30N, Adelite AT-20A, Adelite AT-30A, Adelite AT-40, Adelite AT-50, etc. manufactured by Asahi Denka Kogyo Co., Ltd. Can also be used. In addition, Clariant Japan Co., Ltd. clebosol 30R9, clebosol 30R50, clebosol 50R50, etc., DuPont Ludox (registered trademark) HS-40, Ludox HS-30, Ludox LS, Ludox SM-30, etc. can be used is there.

Examples of colloidal silica using a water-soluble solvent as a dispersion medium include MA-ST-M (methanol dispersion type having a number average particle size of 20 to 25 nm), IPA-ST (number average). Isopropyl alcohol dispersion type with particle diameter of 10-15 nm), EG-ST (ethylene glycol dispersion type with number average particle diameter of 10-15 nm), EG-ST-ZL (ethylene glycol dispersion with number average particle diameter of 70-100 nm) Type), NPC-ST (ethylene glycol monopropyl ether dispersion type having a number average particle diameter of 10 to 15 nm) and the like can be used.
These colloidal silicas may be used alone or in combination of two or more. Moreover, alumina, sodium aluminate, and the like may be included as a minor component. Furthermore, colloidal silica may contain an inorganic base (such as sodium hydroxide, potassium hydroxide, lithium hydroxide, or ammonia), an organic base (such as tetramethylammonium), or the like as a stabilizer.

Component (B): Hydrophilic compound Component (B) is anti-fogging due to improved dispersibility of component (A) and / or immobilization on the surface of component (A) via non-covalent and / or covalent bonds. It is contained in the coating composition for the purpose of improving the durability and moisture resistance and improving the film formability of the coating film.

  As the hydrophilic compound used for the component (B), a compound that can be dissolved and / or dispersed in water can be used from the viewpoint of dispersion stability of the coating composition. As long as it can be dissolved and / or dispersed in water, it may have a hydrophobic group in addition to a hydrophilic group. Moreover, it is preferable from a viewpoint of durability of a coating film to contain the interaction site | part with a metal oxide (A). Examples of such interaction sites include hydroxyl groups, amino groups, amide groups, carboxyl groups, silanol groups, sulfo groups, polyoxyalkylene sites, ammonium salt sites, pyridinium salt sites, imidazolium salt sites, and the like.

As one embodiment, the hydrophilic compound (B) may be at least one selected from the group consisting of a nonionic compound, an anionic compound and a zwitterionic compound. Any of known compounds having these ionic characteristics can be used as the nonionic compound, the anionic compound and the zwitterionic compound.
Examples of nonionic compounds include compounds having a hydroxyl group, a carboxyl group, an amide group, an amino group, etc. as hydrophilic sites.
Examples of the anionic compound include compounds having a carboxylic acid moiety, a sulfonic acid moiety, a phosphoric acid moiety, and a boronic acid moiety.
Examples of zwitterionic compounds include anionic moieties such as carboxylic acid moieties, sulfonic acid moieties, phosphoric acid moieties, boronic acids, and cations such as quaternary ammonium moieties, imidazolium moieties, pyridinium moieties, sulfonium moieties, phosphonium moieties, etc. And compounds having a sex site in the same molecule.

In one embodiment, the hydrophilic compound (B) has one or more, preferably two, functional groups capable of reacting with an isocyanate group (which is a group of the isocyanate compound (C)) in the molecule. You may have it above. Examples of functional groups that can react with isocyanate groups include hydroxyl groups, amino groups, amide groups, carboxyl groups, silanol groups, and sulfo groups.
Among these, the hydrophilic compound (B) is preferably a hydrophilic compound having at least one hydroxyl group in the molecule. A hydrophilic compound having two or more hydroxyl groups in the molecule is more preferred.
By using a hydrophilic compound having a site of interaction with the metal oxide (A), the surface is immobilized on the surface of the metal oxide (A) (for example, colloidal silica) through non-covalent bonds and / or covalent bonds. Improved anti-fogging durability when exposed to high humidity or water.
Further, by using a hydrophilic compound having one or more, preferably two or more functional groups capable of reacting with an isocyanate group in the molecule, the hydrophilic compound is immobilized in the coating film, and water and Elution due to contact can be prevented.
Specifically, examples of the hydrophilic compound (B) having two or more functional groups in the molecule which are the interaction sites and can react with an isocyanate group include, but are not limited to, polyoxyalkylene glycol, polyoxy Alkylene such as alkylene phenyl ether, polyoxyalkylene alkyl aryl ether, polyoxyalkylene sorbitan fatty acid ester, polyoxyethyleneoxypropylene block copolymer, polyoxyethyleneoxypropyleneoxyethylene triblock copolymer, polyoxypropyleneoxyethyleneoxypropylene triblock copolymer Glycol moiety-containing polymer group, polyvinyl alcohol, polyhydroxyalkyl (meth) acrylate, hydroxyalkyl (meth) acrylate and alkyl Examples include (meth) acrylate copolymers. These may be used alone or in combination of two or more. Among these, a polyoxyethyleneoxypropyleneoxyethylene triblock copolymer is preferable from the viewpoints of immobilization on the colloidal silica surface, improvement of antifogging sustainability, and film formability.

In general, in a coating film obtained by applying a coating composition containing a metal oxide and water, the metal oxide component is present on the outermost surface. Therefore, for example, when using the coating composition containing the above-mentioned colloidal silica, the component of a silica exists in the outermost surface of a coating film.
On the other hand, the coating film of the present invention has an element concentration ratio (C1s / M) of C element to metal element obtained from C1s spectrum and metal oxide-derived metal (M) spectrum in elemental analysis by XPS on the surface of 10. That's it. When C1s / M is 10 or more, the degree of exposure of the metal oxide on the surface of the coating film becomes smaller, contamination by foreign matters is suppressed when exposed to a high temperature and high humidity environment, and a desired level of antifogging property is achieved. Maintained. Furthermore, when C1s / M is 10 or more, the difference in thermal expansion coefficient between the resin base material and the coating film becomes small, so that even if the film thickness is 1 μm or more, it is possible to form a film without causing appearance defects such as cracks. .
Further, in the elemental analysis by XPS on the surface, the relative element concentration of C element obtained from the C1s spectrum derived from the carbon-oxygen bond and / or carbon-nitrogen bond is 5 atomic% or more, so that the antifogging property and hydrophilicity of the coating film are improved. The property is further improved.

In elemental analysis by XPS on the surface of the coating film, the lower limit of C1s / M is preferably more than 10 (not including 10), more preferably 10.5 or more, and still more preferably 11 or more.
On the other hand, the upper limit of C1s / M is not limited, but is typically about 50 or less. That is, as a typical non-limiting example, C1s / M may be 10 to 50, 10 to 50, 10.5 to 50, 11 to 50.

Elemental analysis by XPS on the surface of the coating film can be performed, for example, with the following apparatus and measurement conditions.
As an apparatus to be used, for example, Verasa probe II manufactured by ULVAC-PHI Co., Ltd. can be used, and monoAlK · (15 kV × 3.3 mA) can be used as an excitation source. The surface of the coating film of the measurement sample is covered with a 1 mm × 2 mm mask to make the measurement range.
The photoelectron take-off angle is 45 °, and the take-up area is a survey scan of 0 to 1,100 eV and a narrow scan of C1s, N1s, Si2p, and O1s. In addition, Pass Energy is performed at a survey scan of 117.5 eV and a narrow scan of 46.95 eV.

In one embodiment, in the coating film, the method for controlling C1s / M to the above range is as follows: the surface of the metal oxide contained in the coating film contains a C atom and an interaction site with the metal oxide. It can be achieved by coating with the components it contains.
The component containing a C atom is not limited to the following, and examples thereof include an organic component having an interaction site with the hydrophilic compound or other metal oxide described above. Examples of organic components having an interaction with other metal oxides include organic metal oxides such as organic silicon compounds, organic titanium compounds, and organic zirconium compounds. Among these, a hydrophilic compound is preferable. C1s / M can be controlled by making the content of the above components within a certain range with respect to the surface area of the metal oxide.
As the C1s peak, for example, a peak attributed to hydrocarbons observed near 283 to 285 eV, a peak attributed to ether bonds observed near 285 to 287 eV, and an amide bond observed near 288 eV Examples include peaks attributed to urethane bonds observed around 288 to 290 eV.
As a method for controlling the relative element concentration range of the C element obtained from the C1s spectrum derived from the carbon-oxygen bond and / or carbon-nitrogen bond to 5 atomic% or more, carbon-oxygen contained in the hydrophilic compound is used. It can be achieved by the amount of bonds and / or carbon-nitrogen bonds.

Examples of the method for coating the surface of the metal oxide with an organic component such as a hydrophilic compound include (A) the number average particle diameter (D _A ), density (ρ _A ), and the weight ratio of (B) to (A). ( _{B B} ), (B) The average particle diameter (D _B ) of the hydrophilic compound, the density (ρ _B ) of the component (B), and the coverage (P) with respect to (A) of (B) is 300. It is preferable from the viewpoints of film formability and antifogging sustainability that the content of the organic component be controlled to be in the range of at least%. The coverage (P) is more preferably 350% or more, and further preferably 400% or more.

In addition, the average particle diameter (D _B ) of (B) hydrophilic compound can be calculated from the molecular weight and density of (B) hydrophilic compound. When the coverage ratio (P) is 300% or more, the difference in thermal expansion coefficient between the coating film and the resin base material becomes small, and even if the film thickness exceeds 1 μm, there is no appearance defect such as cracks. I can make a film. Furthermore, when the coverage (P) is 300% or more, the exposed amount of the metal oxide on the surface of the coating film becomes smaller, and the antifogging property is maintained even when exposed to a high temperature and high humidity environment.
Here, the weight ratio (W _B ) of ( _B ) to (A) depends on the particle diameters of (A) and (B). When the particle diameter of (A) is 1 to 400 nm, for coverage of 300% or more is 0.04 _{<W B,} for coverage is 400% or more, 0.05 <a _{W B.}

  The coating film of the present invention is further improved in antifogging properties and antifogging durability by setting the water contact angle value to 40 ° or more and the water contact angle change value in the range of 1 to 3. The value of the water contact angle is preferably 40 ° to 60 °, more preferably 40 ° to 50 °. Even when exposed to a high temperature and high humidity environment with a water contact angle of 40 ° or more, diffusion of water vapor into the coating film and swelling of the coating film are suppressed, and the coating film appearance tends to be maintained well. It is in. When the water contact angle is 60 ° or less, the initial antifogging property tends to be good. The upper limit of the water contact angle change is more preferably 2.9 or less, and even more preferably 2.8 or less. In other words, the value of the degree of change in water contact angle is preferably 1 or more and 2.9 or less, more preferably 1 or more and 2.8 or less. When the water contact angle change is 1 or more, when a water droplet adheres to the surface of the coating film, it becomes easy to form a water film instantly, and the antifogging property tends to be good. When the degree of change in water contact angle is 3 or less, swelling of the coating film when exposed to a high temperature and high humidity environment is suppressed, and the appearance tends to be maintained well.

  The hydrophilic compound (B) preferably has an HLB value (hydrophilic / lipophilic balance) determined by the Griffin method of 2 to 14. When the HLB value is 2 or more, the solubility in water is maintained at a predetermined level, which is preferable because it is uniformly dispersed in the aqueous solution and the appearance of the resulting coating film is well maintained. When the HLB value is 14 or less, the interaction with the metal oxide is maintained, and the antifogging durability can be exhibited by immobilization on the metal oxide. Immobilization of the metal oxide and the hydrophilic compound in the aqueous solution by non-covalent bonding can be measured by the presence or absence of a change in particle size by measuring the particle size and the presence or absence of a change in surface tension by measuring the surface tension. (B) The HLB value of the hydrophilic compound is more preferably 2-12.

The solid content concentration of the coating composition used for producing the coating film of the present invention is preferably 15% by mass or more. When the solid content concentration of the coating composition is 15% by mass or more, the network formed by the non-covalent bond and / or the covalent bond of the component (A) and the component (B) is strengthened. It is preferable in terms of moisture resistance.
The pH of the coating composition is preferably less than 8, and more preferably less than 7. When the pH of the coating composition is less than 8, the interaction between the metal oxide and the hydrophilic compound becomes strong. The coating film obtained from such a coating composition has good appearance and moisture resistance.
When preparing a coating composition, it is preferable to prepare a desired concentration by previously mixing a hydrophilic compound and a metal oxide and then diluting with water. By previously mixing the hydrophilic compound and the metal oxide, the hydrophilic compound is firmly bonded to the surface of the metal oxide, and the coating film obtained from such a coating composition has good appearance and moisture resistance.
In addition, the content rate of the water of this coating composition is 85 mass% or less normally on the basis of the total amount of a composition. Moreover, although the minimum of the content rate of water is not specifically limited, Usually, it is 50 mass% or more.

(C) Component: Isocyanate Compound The coating composition for forming a coating film according to the present invention may contain an isocyanate compound as the component (C) in addition to the component (A) and the component (B). The coating composition and the coating film of the present invention formed from the coating composition preferably further contain an isocyanate compound as the component (C) from the viewpoint of improving adhesion to the substrate and improving scratch resistance.

The isocyanate compound (C) in the present invention refers to a compound having at least one isocyanate group in one molecule. The isocyanate compound (C) may be a compound having two or more isocyanate groups in one molecule.
Examples of the isocyanate compound (C) include 1,4-tetramethylene diisocyanate, ethyl (2,6-diisocyanate) hexanoate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2 Aliphatic diisocyanates such as 1,2,4- or 2,4,4-trimethylhexamethylene diisocyanate; 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, Aliphatic triisocyanates such as 2-isocyanatoethyl (2,6-diisocyanato) hexanoate; 1,3- or 1,4-bis (isocyanatomethylcyclohexane), 1,3- or 1,4-diisocyanate Natocyclohexane, 3,5,5-trimethyl ( Cycloaliphatic diisocyanates such as -isocyanatomethyl) cyclohexyl isocyanate, dicyclohexylmethane-4,4'-diisocyanate, 2,5- or 2,6-diisocyanatomethylnorbornane; 2,5- or 2,6- Alicyclic triisocyanates such as diisocyanate methyl-2-isocyanate propyl norbornane; aralkylene diisocyanates such as m-xylylene diisocyanate, α, α, α′α′-tetramethyl-m-xylylene diisocyanate; m -Or p-phenylene diisocyanate, tolylene-2,4- or 2,6-diisocyanate, diphenylmethane-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, diphenyl-4,4'-diisocyanate, 4,4 ' -Diisocyaner Aromatic diisocyanates such as tri-3,3′-dimethyldiphenyl, 3-methyl-diphenylmethane-4,4′-diisocyanate, diphenylether-4,4′-diisocyanate; triphenylmethane triisocyanate, tris (isocyanatophenyl) thio Aromatic triisocyanates such as phosphates, and diisocyanates or polyisocyanates having a uretdione structure obtained by cyclizing and dimerizing the above diisocyanates or the isocyanate groups of the triisocyanates; A polyisocyanate having an isocyanurate structure obtained by quantification; by reacting the above diisocyanate or triisocyanate with water A polyisocyanate having a burette structure; a polyisocyanate having an oxadiazine trione structure obtained by reacting the diisocyanate or triisocyanate with carbon dioxide; and the diisocyanate or triisocyanate being a polyhydroxy compound, a polycarboxy compound, or a polyamine compound. Examples thereof include polyisocyanate obtained by reacting with a compound containing active hydrogen. These can be used alone or in combination. The isocyanate compound may be a blocked polyisocyanate obtained by reacting an isocyanate group with a blocking agent. Examples of the blocking agent include oxime, pyrazole, caprolactam, active methylene, alcohol, phenol, and phenol derivatives.

  Among the above polyisocyanate compounds, aliphatic or alicyclic diisocyanates or triisocyanates, aralkylene diisocyanates, or polyisocyanates derived therefrom are particularly preferable in terms of weather resistance and pot life. Further, as the polyisocyanate, those having a structure such as burette, isocyanurate, urethane, uretdione, and allophanate in the molecule are preferable. Those having a burette structure are often excellent in adhesiveness. Those having an isocyanurate structure are often excellent in weather resistance. Those having a urethane structure using an alcohol compound having a long side chain are often excellent in elasticity and extensibility. Those having a uretdione structure or an allophanate structure often have a low viscosity.

  From the viewpoint of water dispersibility, the isocyanate compound (C) used in the present invention has a polyisocyanate compound having two or more isocyanate groups in one molecule and a nonionic and / or ionic hydrophilic group. A hydrophilic polyisocyanate composition (c1) obtained by reacting a hydroxyl group-containing hydrophilic compound with an isocyanate group / hydroxyl group equivalent ratio in the range of 1.05 to 1,000 is preferred. More preferably, the equivalent ratio is in the range of 2 to 200, more preferably 4 to 100. When the equivalent ratio is 1.05 or more, the isocyanate group content in the hydrophilic polyisocyanate composition (c1) becomes a predetermined level or more, so that the number of crosslinking points in the crosslinkable aqueous coating composition increases. This is preferable because it increases the curing rate or improves the strength of a coating such as a coating film. When the equivalent ratio is 1000 or less, hydrophilicity is expressed, which is preferable.

As such a hydrophilic polyisocyanate composition (c1), any hydrophilic polyisocyanate composition (c1) can be used without particular limitation as long as it has a hydrophilic group introduced by a conventionally known method. For example, the general formula R ¹ O (R ² O) _n —H (where R ¹ is an alkyl group having 1 to 30 carbon atoms or a group containing two or more aromatic rings, R ² is an alkylene having 1 to 5 carbon atoms) (Wherein n is an integer of 2 to 250) and a reaction product of a polyisocyanate compound and a reaction product of a vinyl polymer having a hydrophilic group and a hydroxyl group and a polyisocyanate compound. And a reaction product of an emulsifier obtained by reacting an alkoxypolyalkylene glycol and a dialkanolamine with a polyisocyanate compound. Among these, the general formula R ¹ O— (R ² O) _n —H (wherein R ¹ is an alkyl group having 1 to 30 carbon atoms or a group containing two or more aromatic rings, and R ² is 1 carbon atom) Represents an alkylene group of ˜5, n is an integer of 2 to 250) and a reaction product of a polyisocyanate compound, a vinyl polymer having a hydrophilic group and a hydroxyl group, and a polyisocyanate compound; This reaction product is particularly preferred because of its excellent water dispersibility.

General formula R ¹ O— (R ² O) _n —H (where R ¹ is an alkyl group having 1 to 30 carbon atoms or a group containing two or more aromatic rings, R ² is an alkylene group having 1 to 5 carbon atoms) N is an integer of 2 to 250), for example, polymethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol monopropyl ether, Alkoxy polymers such as polyethylene glycol monolauryl ether, polyoxyethylene-oxypropylene (random and / or block) glycol monomethyl ether, polyoxyethylene-oxytetramethylene (random and / or block) glycol polybutylene glycol monomethyl ether Groups containing two or more aromatic rings such as alkylene glycols, (mono-penta) styrenated phenyl group, mono (or di, tri) styryl-methyl-phenyl group, tribenzylphenyl group, β-naphthyl group Nonionic surfactants having Among these, polyethylene glycol monomethyl ether and nonionic surfactants having a (mono-penta) styrenated phenyl group are preferred in terms of self-emulsifying ability and pot life.
These general formulas R ¹ O— (R ² O) _n —H (where R ¹ is an alkyl group having 1 to 30 carbon atoms or a group containing two or more aromatic rings, R ² is an alkylene having 1 to 5 carbon atoms) (Wherein n represents an integer of 2 to 250), those having a molecular weight of preferably 100 to 10,000, more preferably 300 to 5,000 can be suitably used.

Examples of the hydrophilic group of the vinyl polymer having a hydrophilic group and a hydroxyl group include various known anionic groups, cationic groups, and nonionic groups, and a nonionic group is preferable. By being a nonionic group, the pot life of the coating composition is remarkably extended, and the particle diameter of the polyisocyanate oil droplets is reduced, so that the water resistance of the formed coating film can be further improved.
Specific examples of the vinyl polymer having a hydrophilic group and a hydroxyl group include acrylic polymers, fluoroolefin polymers, vinyl ester polymers, aromatic vinyl polymers, polyolefin polymers, and the like. . Among these, an acrylic polymer is preferable from the viewpoint of the weather resistance of the coating film to be formed.
A polymerization method for obtaining an acrylic polymer suitable as a vinyl polymer having a hydrophilic group and a hydroxyl group is not particularly limited, and examples thereof include suspension polymerization, emulsion polymerization, and solution polymerization. Preferably, it is an acrylic polymer obtained by solution polymerization of an ethylenically unsaturated monomer (i) having a hydrophilic group and an ethylenically unsaturated monomer (ii) having a hydroxyl group. Other ethylenically unsaturated monomers (iii) copolymerizable with these can also be used.

Examples of the ethylenically unsaturated monomer (i) having a hydrophilic group include alkoxy polyalkylene glycols (meta) such as methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, and butoxypolyethylene glycol (meth) acrylate. ) Acrylates, polyalkylene glycol di (meth) acrylates such as polyethylene glycol di (meth) acrylate, (meth) acrylamide monomers, anionic vinyl monomers and the like. Moreover, an ethylenically unsaturated monomer having both a hydrophilic group and a hydroxyl group in the molecule, such as polyalkylene glycol (meth) acrylates, can also be used. You may use these 1 type or in mixture of 2 or more types.
Examples of other ethylenically unsaturated monomers (iii) copolymerizable with these include (meth) acrylic acid esters, aromatic vinyl compounds, vinyl cyanides, carbonyl group-containing vinyl monomers, and olefins. , Dienes, haloolefins, vinyl ethers, allyl esters and the like. You may use these 1 type or in mixture of 2 or more types.
As the vinyl polymer containing a hydrophilic group and a hydroxyl group, those having a weight average molecular weight (GPC method in terms of polystyrene) of 2000 to 100,000, more preferably 3000 to 50000 can be suitably used.

  The ratio (X) of the polyisocyanate compound (C) to the hydrophilic compound (B) in the coating composition (calculated as solid weight ratio (X) = (C) / (B)) From the viewpoint of adhesion to the substrate, 0.02 or more is preferable, and 0.1 or more is more preferable. Further, from the viewpoint of the stability of the coating composition (suppression of gelation and increase in viscosity), 10 or less is preferable, and from the viewpoint of high transparency (low Haze) of the formed coating film, 5 or less is more preferable. The ratio (X) may be 0.02 or more and 10 or less, 0.02 or more and 5 or less, 0.1 or more and 10 or less, or 0.1 or more and 5 or less.

  The viscosity of the isocyanate compound (C) is preferably 1 to 50000 mPa · s (20 ° C.), more preferably 1 to 20000 mPa · s (20 ° C.), and further preferably 10 to 10000 mPa · s (20 ° C.). is there. The viscosity of the isocyanate compound (C) may be 10 to 50000 mPa · s (20 ° C.), 10 to 20000 mPa · s (20 ° C.), or 10 to 10000 mPa · s (20 ° C.). The viscosity of the polyisocyanate compound (C) is preferably 50000 mPa · s or less because it can be easily dispersed in water. The viscosity here can be measured with a general E-type viscometer. In one embodiment, the viscosity is measured using an E-type viscometer (RE-80U manufactured by Toki Sangyo Co., Ltd.) at a rotation speed of 2.5 rpm and 25 ° C.

Component (D): Polymer particles The coating composition for forming a coating film according to the present invention may contain polymer particles as the component (D) in addition to the components (A) and (B). In addition to the component (A), the component (B) and the component (C), the coating composition may contain polymer particles as the component (D). The coating composition (and the coating film of the present invention formed therefrom) preferably further contains polymer particles as component (D). In one embodiment, the component (D) is at least one selected from the group consisting of the component (d1): a hydrolyzable silicon compound and the component (d2): a hydroxyl group, a carboxyl group, an amide group, an amino group, and an ether group. It is a polymer particle obtained by polymerizing a polymerization stock solution containing a vinyl monomer containing a seed functional group, (d3) component: emulsifier, and (d4) component: water.

  In one embodiment, the component (A) can interact with the component (D) and act as a curing agent for the component (D). Examples of the interaction include a hydrogen bond between a hydroxyl group that the component (A) generally has and a functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amide group, an amino group, and an ether group that the component (D) has. Or the condensation (chemical bond) of the hydroxyl group generally possessed by the component (A) and the polymerization product of the component (d1) constituting the component (D). Moreover, it is preferable that (A) component forms a continuous layer between the particles of (D) component, interacting with (D) component. Thereby, the adhesiveness of the obtained coating film, water resistance, and a weather resistance can improve more.

(D1) As a component, the compound represented by following formula (4), its condensation product, a silane coupling agent, etc. can be used.
SiW _x R _y (4)
(In Formula (4), W represents an alkoxy group having 1 to 20 carbon atoms, a hydroxyl group, an acetoxy group having 1 to 20 carbon atoms, a halogen atom, a hydrogen atom, an oxime group having 1 to 20 carbon atoms, an enoxy group, an aminoxy group, R represents at least one group selected from amide groups, and R represents a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, and a substituted group. Or at least one hydrocarbon group selected from an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms substituted with a halogen atom. Is an integer of 1 or more and 4 or less, and y is an integer of 0 or more and 3 or less, and x + y = 4.

  The silane coupling agent means a compound in which a functional group having reactivity with an organic substance such as a vinyl polymerizable group, an epoxy group, an amino group, a methacryl group, a mercapto group, or an isocyanate group exists in the molecule.

  Specific examples of the compound represented by the formula (4) include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane; Trimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxy Run, allyltrimethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3,3,3-tri Fluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2-hydroxyethyltriethoxysilane 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, Captopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxy Silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acrylic Oxypropyltriethoxysilane, 3- (meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysilane, 3-ureidopropyltrimethoxysilane, 3- Trialkoxysilanes such as ureidopropyltriethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, diisopropyldimethoxysilane Diisopropyldiethoxysilane, di-n-butyldimethoxysilane, di-n-butyldiethoxysilane, di-n-pentyldimethoxysilane, di-n-pentyldiethoxysilane, di-n-hexyldimethoxysilane, di- n-hexyldiethoxysilane, di-n-heptyldimethoxysilane, di-n-heptyldiethoxysilane, di-n-octyldimethoxysilane, di-n-octyldiethoxysilane, di-n-cyclohexyldimethoxy Dialkoxysilanes such as lan, di-n-cyclohexyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane; monoalkoxysilanes such as trimethylmethoxysilane and trimethylethoxysilane Kinds can be used. Moreover, these may be used independently and may be used in mixture of 2 or more types.

  As the component (d1), a silicon alkoxide having a phenyl group (for example, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, etc.) can be used. When a silicon alkoxide having a phenyl group is used, the polymerization stability in the presence of water and an emulsifier becomes good, which is preferable.

  Furthermore, the component (d1) may contain a silane coupling agent having a thiol group and a hydrolyzable silicon compound having a vinyl polymerizable group as the component (d1-1). When these are used, the long-term antifouling property of the obtained coating film becomes good, which is preferable. As the silane coupling agent having a thiol group, for example, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and the like can be used.

  Examples of the component (d1-1) include 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane, 3 -(Meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, 2-trimethoxysilylethyl vinyl ether, etc. A silane coupling agent having a vinyl polymerizable group can be used.

  These silane coupling agents can generate chemical bonds by copolymerization or chain transfer reaction with the component (d2) described later. For this reason, when a silane coupling agent having a vinyl polymerizable group or a thiol group is used by mixing or combining with the component (d1) described above, the polymerization product of (d1) and the polymerization of the component (d2) described later are used. The product can be complexed by chemical bonds. The “vinyl polymerizable group” of the component (d1-1) is, for example, a vinyl group, an allyl group, and the like, and among them, a 3- (meth) acryloxypropyl group is preferable.

The component (d1) may contain a cyclic siloxane oligomer as the component (d1-2). By using the component (d1-2), the flexibility of the composite of the obtained coating film and the substrate is increased, which is suitable for hard coating.
As the cyclic siloxane oligomer, a compound represented by the following formula (5) can be used.
(R ′ ₂ SiO) _m (5)
(In Formula (5), R ′ is a hydrogen atom, a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, and unsubstituted or substituted. It represents at least one selected from an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms substituted with a halogen atom, m is an integer, and 2 ≦ m ≦ 20.)

  Among the cyclic siloxane oligomers, cyclic dimethylsiloxane oligomers such as octamethylcyclotetrasiloxane are preferable from the viewpoint of reactivity.

  In addition, when (d1) component is used as a condensation product, the polystyrene conversion weight average molecular weight (according to GPC method) of the condensation product is preferably 200 to 5000, and more preferably 300 to 1000. The ratio (d1) / (D) between the mass of the component (d1) of the polymerization stock solution and the mass of the polymer particles of the component (D) is preferably 0.01 / 100 to 80 / from the viewpoint of polymerization stability. 100, more preferably 0.1 / 100 to 70/100. On the other hand, the ratio (d1-1) / (D) between the mass of the component (d1-1) of the polymerization stock solution and the mass of the polymer particles of the component (D) is preferably from the viewpoint of polymerization stability. It is 01 / 100-20 / 100, More preferably, it is 0.5 / 100-10 / 100.

  The mass ratio (d1-1) / (d2) between the component (d1-1) and the component (d2) in the polymerization stock solution is preferably 0.1 / 100 to 100/100 from the viewpoint of polymerization stability. More preferably, it is 0.5 / 100 to 50/100. On the other hand, the ratio (d1-2) / (D) of the mass of the (d1-2) component of the polymerization stock solution and the mass of the polymer particles of the (D) component is preferably 0.01 from the viewpoint of hydrophilicity. / 100 to 20/100, more preferably 0.5 / 100 to 5/100. The mass ratio (d1-2) / (d2) between the component (d1-2) and the component (d2) in the polymerization stock solution is preferably 0.5 / 100 to 50/100 from the viewpoint of polymerization stability. More preferably, it is 1.0 / 100 to 20/100.

  Next, examples of the hydroxyl group-containing vinyl monomer as the component (d2) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. Various hydroxyalkyl (meth) acrylates; various hydroxyl group-containing vinyl ethers such as 2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether; various hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether; polyethylene glycol Monoesters of polyoxyalkylene glycols obtained from various polyether polyols as typified by, and various unsaturated carboxylic acids as typified by (meth) acrylic acid, etc .; Containing hydroxyl groups Adducts of monomers and various lactones such as ε-caprolactone; various epoxy group-containing unsaturated monomers such as glycidyl (meth) acrylate and acetic acid Adducts with various acids as typified by, etc .; furthermore, various unsaturated carboxylic acids as typified by (meth) acrylic acid, etc., and “Cardura E” (a product made by Shell, Netherlands) Various hydroxyl group-containing vinyl monomers such as adducts with various monoepoxy compounds other than the epoxide of α-olefin as represented by the name) can be used.

  Further, the carboxyl group-containing vinyl monomer as the component (d2) includes various kinds of solvents such as (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, crotonic acid, itaconic acid, maleic acid and fumaric acid. Saturated carboxylic acids; saturated with unsaturated dicarboxylic acids such as monomethyl itaconate, mono-n-butyl itaconate, monomethyl maleate, mono-n-butyl maleate, monomethyl fumarate, and mono-n-butyl fumarate Monoesters with monohydric alcohols (half esters); Monovinyl esters of various saturated dicarboxylic acids such as monovinyl adipate and monovinyl succinate; succinic anhydride, glutaric anhydride, phthalic anhydride, and tri Various saturated polycarboxylic acid anhydrides such as merit acid and each of the aforementioned Addition reaction products with hydroxyl group-containing vinyl monomers; and monomers obtained by addition reaction of the above-mentioned various carboxyl group-containing monomers with lactones can be used. is there.

  As the amide group-containing vinyl monomer as the component (d2), for example, N-alkyl or N-alkylene-substituted (meth) acrylamide can be used. More specifically, N-methylacrylamide, N-methylmethacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N-ethylmethacrylamide, N-methyl-N-ethylacrylamide, N-methyl-N-ethylmethacrylamide, N-isopropylacrylamide, Nn-propylacrylamide, N-isopropylmethacrylamide, Nn-propylmethacrylamide, N-methyl-N -N-propylacrylamide, N-methyl-N-isopropylacrylamide, N-acryloylpyrrolidine, N-methacryloylpyrrolidine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloyl Sahydroazepine, N-acryloylmorpholine, N-methacryloylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, N, N'-methylenebisacrylamide, N, N'-methylenebismethacrylamide, N-vinylacetamide, diacetone Acrylamide, diacetone methacrylamide, N-methylol acrylamide, N-methylol methacrylamide and the like can be used.

  As the amino group-containing vinyl monomer as the component (d2), 2-dimethylaminoethyl (meth) acrylate, 2-diethylaminoethyl (meth) acrylate, 2-di-n-propylaminoethyl (meth) acrylate, 3 -Various tertiary amino group-containing (meth) acrylic esters such as dimethylaminopropyl (meth) acrylate, 4-dimethylaminobutyl (meth) acrylate, and N- [2- (meth) acryloyloxy] ethylmorpholine Various tertiary amino group-containing aromatic vinyl monomers such as vinylpyridine and N-vinylcarbazole N-vinylquinoline; N- (2-dimethylamino) ethyl (meth) acrylamide, N- (2 -Diethylamino) ethyl (meth) acrylamide, N- (2-di-n-propyla) C) ethyl (meth) acrylamide, N- (3-dimethylamino) propyl (meth) acrylamide, N- (4-dimethylamino) butyl (meth) acrylamide, and N- [2- (meth) acrylamide] ethylmorpholine. Various tertiary amino group-containing (meth) acrylamides; N- (2-dimethylamino) ethylcrotonic acid amide, N- (2-diethylamino) ethylcrotonic acid amide, N- (2-di-n-propyl) Various tertiary amino group-containing crotonic acid amides such as amino) ethyl crotonic acid amide, N- (3-dimethylamino) propyl crotonic acid amide, and N- (4-dimethylamino) butyl crotonic acid amide; Dimethylaminoethyl vinyl ether, 2-diethylaminoethyl vinyl ether, 3-dimethyla Bruno propyl vinyl ether, and 4 various tertiary amino group-containing vinyl ethers such as dimethyl amino butyl vinyl ether or the like can be used.

  Examples of the ether group-containing vinyl monomer as the component (d2) include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene higher fatty acid ester, and polyoxyethylene-polyoxypropylene block copolymer. Vinyl ethers having various polyether chains in the side chain, allyl ethers or vinyl monomers such as (meth) acrylic acid esters can be used. Specifically, Bremer PE-90, PE-200, PE-350, PME-100, PME-200, PME-400, AE-350 [above, manufactured by NOF Corporation], MA-30, MA- 50, MA-100, MA-150, RA-1120, RA-2614, RMA-564, RMA-568, RMA-1114, and MPG130-MA [above, manufactured by Nippon Emulsifier Co., Ltd.] can be used. . Here, as for the oxyethylene unit of a polyoxyethylene chain, 2-30 are preferable. When the oxyethylene unit is 2 or more, moderate flexibility of the coating film is obtained, and when it is 30 or less, excessive softening of the coating film is suppressed and blocking resistance is maintained.

  The vinyl monomer as the component (d2) preferably has a secondary and / or tertiary amide group from the viewpoint of further improving the hydrogen bondability with other components.

  The ratio (d2) / (D) of the mass of the (d2) component of the polymerization stock solution and the mass of the polymer particles of the (D) component is preferably 0.1 / 1 to 0. 0 from the viewpoint of polymerization stability. 5/1, more preferably 0.2 / 1 to 0.4 / 1. Further, the ratio (d2) / (A) of the mass of the component (d2) of the polymerization stock solution to the mass of the metal oxide of the component (A) is a viewpoint of hydrogen bonding property and blending stability with the component (A). Therefore, it is preferably 0.1 / 1 to 1/1, and more preferably 0.2 / 1 to 0.8 / 1.

  Next, as the emulsifier as the component (d3), for example, alkylbenzene sulfonic acid, alkyl sulfonic acid, alkyl sulfosuccinic acid, polyoxyethylene alkyl sulfuric acid, polyoxyethylene alkyl aryl sulfuric acid, polyoxyethylene distyryl phenyl ether sulfonic acid, etc. Acidic emulsifiers, alkali metal (Li, Na, K, etc.) salts of acidic emulsifiers, ammonium salts of acidic emulsifiers and anionic surfactants such as fatty acid soaps; alkyltrimethylammonium bromide, alkylpyridinium bromide, imidazolinium laurate Quaternary ammonium salts such as quaternary ammonium salts, pyridinium salts, and imidazolinium salt type cationic surfactants; polyoxyethylene alkyl aryl ethers, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene Emissions polyoxypropylene block copolymers, and nonionic surfactants such as polyoxyethylene distyryl phenyl ether can be used. These may be used individually by 1 type, or may use 2 or more types together.

  As the component (d3), a reaction having a radical polymerizable double bond from the viewpoint of improving the water dispersion stability of the obtained component (D) and improving the long-term antifouling property of the obtained coating film. It is preferable to use a functional emulsifier. More specifically, reactive emulsifiers include vinyl monomers having a sulfonic acid group or sulfonate group, vinyl monomers having a sulfate ester group, and alkali metal salts, ammonium salts, and nonions such as polyoxyethylene. A vinyl monomer having a group, a vinyl monomer having a quaternary ammonium salt, or the like can be used.

  As the vinyl monomer having a sulfonic acid group or a sulfonate group, for example, it has a radical polymerizable double bond, and a part thereof is substituted by a substituent such as an ammonium salt, a sodium salt or a potassium salt of the sulfonic acid group. Selected from the group consisting of substituted alkyl groups having 1 to 20 carbon atoms, alkyl ether groups having 2 to 4 carbon atoms, polyalkyl ether groups having 2 to 4 carbon atoms, phenyl groups, naphthyl groups, and succinic acid groups. A compound having a substituent; a vinyl sulfonate compound having a vinyl group to which a substituent is bonded, such as an ammonium salt, a sodium salt or a potassium salt of a sulfonic acid group, can be used.

  As the vinyl monomer having a sulfate ester group, for example, it has a radical polymerizable double bond and is partially substituted by a substituent such as an ammonium salt, sodium salt or potassium salt of the sulfate ester group. A compound having a substituent selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkyl ether group having 2 to 4 carbon atoms, a polyalkyl ether group having 2 to 4 carbon atoms, a phenyl group, and a naphthyl group Is possible.

  As the compound having a succinic acid group partially substituted with a substituent such as ammonium salt, sodium salt or potassium salt of sulfonic acid group, specifically, allylsulfosuccinate can be used. More specifically, Eleminol JS-2 (trade name) (manufactured by Sanyo Chemical Co., Ltd.), Latemuru S-120, S-180A, and S-180 (trade name) (manufactured by Kao Corporation) are used. Is possible.

  In addition, as a compound having a C2-C4 alkyl ether group or a C2-C4 polyalkyl ether group partially substituted with a group which is an ammonium salt, sodium salt or potassium salt of a sulfonic acid group Specifically, Aqualon HS-10 or KH-1025 (trade name) (Daiichi Kogyo Seiyaku Co., Ltd.), Adekaria Soap SE-1025N or SR-1025 (trade name) (Asahi Denka Kogyo Co., Ltd.) Etc.) can be used.

  As the vinyl monomer having a nonionic group, specifically, α- [1-[(allyloxy) methyl] -2- (nonylphenoxy) ethyl] -ω-hydroxypolyoxyethylene (trade name: ADEKA) Rear soap NE-20, NE-30, NE-40, etc., manufactured by Asahi Denka Kogyo Co., Ltd.) and polyoxyethylene alkylpropenyl phenyl ether (trade names: Aqualon RN-10, RN-20, RN-30, RN) -50, etc. (Daiichi Pharmaceutical Co., Ltd.) can be used.

  The amount of the component (d3) used in the polymerization stock solution is preferably 10 parts by mass or less, more preferably 0. 0 parts by mass with respect to 100 parts by mass of the component (D) polymer particles from the viewpoint of polymerization stability. 001 to 5 parts by mass.

  In one embodiment, the component (D) of the coating film is polymer particles obtained by polymerizing a polymerization stock solution containing the components (d1) to (d3) described above and water as the component (d4). . In addition, the usage-amount of (d4) component becomes like this. Preferably it is 30-99.9 mass% as a content rate in a polymerization undiluted | stock solution from a viewpoint of superposition | polymerization stability. In addition to the components (d1) to (d4), various components can be further mixed into the polymerization stock solution. For example, the polymerization stock solution may be mixed with another vinyl monomer copolymerizable with the component (d2) as the component (d5). Viewpoints for controlling the properties (such as glass transition temperature, molecular weight, hydrogen bonding strength, polarity, dispersion stability, weather resistance, and compatibility of the hydrolyzable silicon compound (d1) with the polymerization product) Therefore, it is preferable to use the component (d5).

  Examples of the component (d5) include acrylic acid esters, methacrylic acid esters, aromatic vinyl compounds, vinyl cyanides, epoxy group-containing vinyl monomers, carbonyl group-containing vinyl monomers, anionic vinyl monomers. A monomer containing a functional group such as a body can be used. The proportion of the component (d5) in the total vinyl monomer in the polymerization stock solution is preferably in the range of 0.001 to 30% by mass, more preferably in the range of 0.05 to 10% by mass. Viewpoints for controlling the properties (such as glass transition temperature, molecular weight, hydrogen bonding strength, polarity, dispersion stability, weather resistance, and compatibility of the hydrolyzable silicon compound (d1) with the polymerization product) Therefore, it is preferable to set the mass% range.

  Further, a chain transfer agent may be mixed in the polymerization stock solution. Examples of chain transfer agents include alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, and t-dodecyl mercaptan; aromatic mercaptans such as benzyl mercaptan and dodecyl benzyl mercaptan; thiomalic acid and the like Thiocarboxylic acids or their salts or their alkyl esters, or polythiols, diisopropylxanthogen disulfide, di (methylenetrimethylolpropane) xanthogen disulfide and thioglycol, and allyl compounds such as α-methylstyrene dimers can be used. It is. The amount of the chain transfer agent used is preferably 0.001 to 30 parts by mass, more preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the total amount of all vinyl monomers from the viewpoint of polymerization stability. Part.

  Further, a dispersion stabilizer may be mixed in the polymerization stock solution. Examples of the dispersion stabilizer include various water-soluble oligomers selected from the group consisting of polycarboxylic acids and sulfonates, polyvinyl alcohol, hydroxyethyl cellulose, starch, maleated polybutadiene, maleated alkyd resin, polyacrylic acid ( Salt), polyacrylamide, water-soluble or water-dispersible acrylic resin and the like, and various water-soluble polymer substances of synthetic or natural water-solubility or water-dispersibility can be used. Moreover, the 1 type (s) or 2 or more types of mixture can be used. The amount of the dispersion stabilizer in the polymerization stock solution is preferably 10 parts by mass or less, and more preferably 0.001 to 5 parts by mass with respect to 100 parts by mass of the polymer particles (D).

  The polymerization of the polymerization stock solution is preferably carried out in the presence of a polymerization catalyst. Examples of the polymerization catalyst of component (d1) include hydrogen halides such as hydrochloric acid and hydrofluoric acid, carboxylic acids such as acetic acid, trichloroacetic acid, trifluoroacetic acid, and lactic acid, sulfonic acids such as sulfuric acid and p-toluenesulfonic acid, Acid emulsifiers such as alkylbenzene sulfonic acid, alkyl sulfonic acid, alkyl sulfosuccinic acid, polyoxyethylene alkyl sulfuric acid, polyoxyethylene alkyl aryl sulfuric acid, polyoxyethylene distyryl phenyl ether sulfonic acid, acidic or weakly acidic inorganic salt, phthalic acid Acidic compounds such as sodium hydroxide, phosphoric acid and nitric acid; sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, tetramethylammonium chloride, tetramethylammonium hydroxide, tributylamine, diazabicycloundecene, ethylene Basic compounds such as amines, diethylenetriamine, ethanolamines, γ-aminopropyltrimethoxysilane, and γ- (2-aminoethyl) -aminopropyltrimethoxysilane; such as dibutyltin octylate and dibutyltin dilaurate Tin compounds and the like can be used. Among them, as a polymerization catalyst for the hydrolyzable silicon compound (d1), acidic emulsifiers that act not only as a polymerization catalyst but also as an emulsifier, particularly alkylbenzenesulfonic acids having 5 to 30 carbon atoms (such as dodecylbenzenesulfonic acid) are used. preferable.

  As the polymerization catalyst for the component (d2), a radical polymerization catalyst that causes radical polymerization by heat or a reducing substance to cause addition polymerization of a vinyl monomer is suitable. Water-soluble or oil-soluble persulfates, peroxides, azobis compounds and the like are preferably used. More specifically, potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, 2,2-azobisisobutyronitrile, 2,2- Azobis (2-diaminopropane) hydrochloride, 2,2-azobis (2,4-dimethylvaleronitrile) and the like can be used.

  The amount of the polymerization catalyst used in the polymerization stock solution is preferably 0.001 to 5 parts by mass with respect to 100 parts by mass of all vinyl monomers. When acceleration of the polymerization rate and polymerization at a low temperature such as 70 ° C. or lower are desired, for example, a reducing agent such as sodium bisulfite, ferrous chloride, ascorbate, and Rongalite is combined with a radical polymerization catalyst. It is advantageous to use it.

  In one embodiment, the polymerization of the component (d1) and the polymerization of the component (d2) can be performed separately. However, when the polymerization is performed at the same time, a micro organic / inorganic composite by hydrogen bonding or the like is formed. This is preferable because it can be achieved.

  As a method for obtaining the component (D) of the coating film according to one embodiment, the emulsifier polymerizes the component (d1) and the component (d2) in the presence of a sufficient amount of water to form micelles. So-called emulsion polymerization is suitable. As a method of emulsion polymerization, for example, (d1) component and (d2) component, and further, (d3) component as necessary, as it is or in an emulsified state, batchwise or divided or continuously in a reaction vessel A method of polymerizing at a reaction temperature of about 30 to 150 ° C. in the presence of a polymerization catalyst, preferably in the presence of a polymerization catalyst, preferably from atmospheric pressure to 10 MPa as required. In some cases, the polymerization may be carried out at a higher pressure or lower temperature. In addition, as mixing | blending of superposition | polymerization stock solution, from a viewpoint of superposition | polymerization stability, final solid content is 0.1-70 mass%, Preferably each component of (d1)-(d4) is used as the range of 1-55 mass%. Is preferably blended.

  Furthermore, when performing emulsion polymerization, it is preferable to use a seed polymerization method from the viewpoint of appropriately growing or controlling the particle diameter. The seed polymerization method is a method in which emulsion particles (seed particles) are previously present in an aqueous phase for polymerization. The pH in the polymerization system when performing the seed polymerization method is preferably 1.0 to 10.0, and more preferably 1.0 to 6.0. The pH during the polymerization can be adjusted using a disodium phosphate, borax, or a pH buffer such as sodium bicarbonate or ammonia.

  In addition, as a method for obtaining the component (D), in the presence of the component (d3) and the component (d4) necessary for polymerizing the component (d1), the component (d1) and the component (d2) are optionally mixed with a solvent. It is also possible to use a technique in which water is added after the polymerization in the presence until the polymerization product becomes an emulsion.

  Furthermore, the component (D) includes a core layer and one or more shell layers covering the core layer from the viewpoint of improving the base material adhesion of the coating film formed using the resulting coating composition. And having a core / shell structure. As a method for forming the core / shell structure, multistage emulsion polymerization in which emulsion polymerization is performed in multiple stages is useful.

  In the multi-stage emulsion polymerization, for example, in the presence of the component (d3) and the component (d4), at least one selected from the group consisting of the components (d1), (d2), and (d5) is polymerized to form seed particles. The second step of polymerizing is carried out by adding a polymerization stock solution containing the components (d1) and (d2) and, if necessary, the component (d5) in the presence of seed particles. Stages are carried out (two-stage polymerization process). Furthermore, when implementing multistage emulsion polymerization of 3 steps | paragraphs or more, the 3rd step | paragraph which superposes | polymerizes by adding the polymerization stock solution containing (d1) component and (d2) component, and (d5) component as needed may be implemented. . Such a method is also suitable from the viewpoint of polymerization stability. From the viewpoint of polymerization stability, the mass ratio (d2) / (d1) between the component (d2) and the component (d1) in the core layer is preferably 0.01 / 1 to 1/1. In the outermost layer of the shell layer, the mass ratio (d2) / (d1) between the component (d2) and the component (d1) is preferably 0.1 / 1 to 5/1, and more preferably 0.8. 5/1 to 4/1.

  In the two-stage polymerization method, the mass ratio of the solid content mass (M1) in the polymerization stock solution used in the first stage to the solid content mass (M2) in the polymerization stock solution added in the second stage is determined by the polymerization stability. In view of the above, preferably (M1) / (M2) = 9/1 to 1/9, more preferably 8/2 to 2/8.

  In addition, in the core / shell structure, from the viewpoint of polymerization stability, the particle size distribution of the seed particles (volume average particle size / number average particle size) did not change greatly, and the particle size increased by the second stage polymerization. It preferably has a structure. The volume average particle diameter can be measured in the same manner as the number average particle diameter. The core / shell structure can be observed by, for example, morphological observation with a transmission electron microscope or the like, analysis by viscoelasticity measurement, or the like.

  The glass transition temperature (Tg) of the core layer of the core / shell structure is preferably 0 ° C. or lower. When the glass transition temperature (Tg) of the core layer is within this range, the physical properties of the resulting coating film are excellent in flexibility at room temperature, and cracks and the like are less likely to occur. Here, Tg can be measured with a differential scanning calorimeter (DSC).

  In one embodiment, the number average particle diameter of the component (D) of the coating composition (and the coating film formed therefrom) is, for example, 10 nm to 800 nm. By forming the composition by combining the component (D) having a number average particle size of 10 nm to 800 nm and the component (A) having a number average particle size of 1 nm to 400 nm, the weather resistance and antifouling properties of the resulting coating film are obtained. Becomes better. Moreover, from the viewpoint of the optical properties and hard coat properties of the resulting coating film, the number average particle diameter of the component (D) is preferably 20 nm to 250 nm. About the measuring method of the number average particle diameter of (D) component, the same thing as (A) component may be employ | adopted.

  The mass ratio (A) / (D) of the component (A) and the component (D) in the coating composition (and the coating film formed therefrom) is preferably 50/100 to 1000/100, more preferably. 100/100 to 300/100. By mix | blending in this range, the coating film excellent in hydrophilic property, anti-fogging property, an optical characteristic, and antifouling property can be formed. The ratio (SA) / (SB) of the surface area (SA) of all particles of the component (A) and the surface area (SB) of all particles of the component (B) is preferably in the range of 0.001 to 1000. . In addition, the surface area here is computable from each particle diameter of (A) component and (B) component, and each compounding mass number (namely, particle diameter distribution).

Component (E): Hydrolyzable silicon compound The coating composition for forming a coating film according to the present invention contains a hydrolyzable silicon compound as component (E) in addition to component (A) and component (B). It's okay. The coating composition may contain a hydrolyzable silicon compound as the component (E) in addition to the component (A), the component (B), and the component (C). In addition to the component (A), the component (B) and the component (D), the coating composition may contain a hydrolyzable silicon compound as the component (E). In addition to the component (A), the component (B), the component (C) and the component (D), the coating composition may contain a hydrolyzable silicon compound as the component (E).
In one embodiment, the coating composition (and the coating film formed therefrom) is a hydrolyzable silicon represented by component (E): the following formula (6), the following formula (7), or the following formula (8). It may further contain a compound. In this case, the mass ratio of the component (A) to the component (D) in the coating composition is, for example, A / D = 50/100 to 1000/100, and the mass ratio of the component (A) to the component (E). Is, for example, E / A = 5/100 to 90/100. Hereinafter, the hydrolyzable silicon-containing compound represented by the following formula (6) is referred to as component (e1), and the hydrolyzable silicon-containing compound represented by the following formula (7) is referred to as component (e2).
R ¹ _n SiX _4-n (6)
(In the formula (6), R ¹ represents hydrogen or an alkyl group having 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, or an aryl group. Further, a halogen group, a hydroxy group, a mercapto group, an amino group is further added to these substituents. May have a functional group such as a group, a (meth) acryloyl group, an epoxy group, etc. X represents a hydrolyzable group, n is an integer of 0 to 3. A hydrolyzable group has a hydroxyl group by hydrolysis. Any group may be used, and examples thereof include a halogen atom, an alkoxy group, an acyloxy group, an amino group, a phenoxy group, and an oxime group.
_{^{X 3 Si-R 2 n -SiX}} 3 (7)
(In the formula (7), X represents a hydrolyzable group, R ² represents an alkylene group having 1 to 6 carbon atoms or a phenylene group, and n is 0 or 1.)

  Specifically, as the component (e1) and the component (e2), tetramethoxysilane, tetraethoxysilane, tetra (n-propoxy) silane, tetra (i-propoxy) silane, tetra (n-butoxy) silane, tetra (I-butoxy) silane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyl Trimethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxysilane, diethoxysilane, methyldimethoxysilane, Rudiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane, bis (triphenoxysilyl) methane, bis (trimethoxysilyl) ethane, bis (triethoxysilyl) ) Ethane, bis (triphenoxysilyl) ethane, 1,3-bis (trimethoxysilyl) propane, 1,3-bis (triethoxysilyl) propane, 1,3-bis (triphenoxysilyl) propane, 1,4 -Bis (trimethoxysilyl) benzene, 1,4-bis (triethoxysilyl) benzene, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltri Ethoxysilane, 3 Mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxy Silane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, tetraacetoxysilane, tetrakis (trichloroacetoxy) silane, tetrakis (trifluoroacetoxy) silane, triacetoxysilane, tris (trichloroacetoxy) silane, Tris (trifluoroacetoxy) silane, methyltriacetoxysilane, methyltris (trichloroacetoxy) silane, tetrachlorosilane, tetrabromosila , Tetrafluorosilane, trichlorosilane, tribromosilane, trifluorosilane, methyltrichlorosilane, methyltribromosilane, methyltrifluorosilane, tetrakis (methylethylketoxime) silane, tris (methylethylketoxime) silane, methyltris (methylethylketoxime) Silane, phenyltris (methylethylketoxime) silane, bis (methylethylketoxime) silane, methylbis (methylethylketoxime) silane, hexamethyldisilazane, hexamethylcyclotrisilazane, bis (dimethylamino) dimethylsilane, bis (diethylamino) dimethylsilane, Bis (dimethylamino) methylsilane, bis (diethylamino) methylsilane, or the like can be used.

Moreover, let the hydrolyzable silicon containing compound represented by following formula (8) be (e3) component. As the component (e3), specifically, a partial hydrolysis condensate of tetramethoxysilane (trade name “M silicate 51” manufactured by Tama Chemical Industry Co., Ltd., trade name “MSI51” manufactured by Colcoat Co., Ltd.), product Names “MS51” and “MS56” manufactured by Mitsubishi Chemical Corporation), partially hydrolyzed condensates of tetoethoxysilane (trade names “silicate 35” and “silicate 45” manufactured by Tama Chemical Industries, Ltd., trade name “ESI40” , "ESI48" manufactured by Colcoat Co., Ltd.), and a co-partial hydrolysis condensate of tetramethoxysilane and tetraethoxysilane (trade name "FR-3" manufactured by Tama Chemical Industry Co., Ltd., trade name "EMSi48" Colcoat ( Etc.) can be used.
R ³ — (O—Si (OR ³ ) ₂ ) _n —OR ³ (8)
(In the formula (8), ^{R 3} is .n represents an alkyl group having 1 to 6 carbon atoms is an integer of 2-8.)

  The hydrolyzable silicon compound (E) may be used alone or as a mixture of two or more. The mass ratio of the component (A) to the component (E) in the coating composition is E / A = 5/100 to 90/100, preferably E / A = 5/100 to 70/100. . When the E / A is 5/100 or more, the scratch resistance of the formed coating film can be made sufficient. When the E / A is 90/100 or less, the strength of the coating film is increased. Appropriately held and good hard coat performance is obtained.

Other optional components The coating composition for forming a coating film according to the present invention includes optional components ((C), (D) or (E) other than the component) may be included. Further, the coating composition may contain an optional component (other than the component (D) or (E)) as exemplified below in addition to the component (A), the component (B) and the component (C). . Further, the coating composition may contain an optional component (other than the component (C) or (E)) as exemplified below in addition to the component (A), the component (B) and the component (D). . Further, the coating composition may include an optional component (other than the component (C) or (D)) as exemplified below in addition to the component (A), the component (B) and the component (E). . In addition to the component (A), the component (B), the component (C), and the component (D), the coating composition includes an optional component (other than the component (E)) as exemplified below. Good. In addition to the component (A), the component (B), the component (C) and the component (E), the coating composition includes an optional component (other than the component (D)) as exemplified below. Good. In addition to the component (A), the component (B), the component (D), and the component (E), the coating composition includes an optional component (other than the component (C)) as exemplified below. Good. Moreover, the coating composition may contain an optional component as exemplified below in addition to the component (A), the component (B), the component (C), the component (D), and the component (E).
In one embodiment, a coating composition for obtaining a coating film is usually added to a paint or a molding resin depending on its use and usage method, for example, an additive component such as a surfactant, light, etc. Stabilizer, UV absorber, thickener, leveling agent, thixotropic agent, antifoaming agent, freezing stabilizer, matting agent, crosslinking reaction catalyst, pigment, curing catalyst, crosslinking agent, filler, anti-skinning agent, Dispersant, wetting agent, antioxidant, UV absorber, rheology control agent, film forming aid, rust inhibitor, dye, plasticizer, lubricant, reducing agent, preservative, antifungal agent, deodorant, yellow An anti-change agent, an antistatic agent, a charge control agent, or the like can be selected and combined depending on the purpose.

  Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonic acid, fatty acid sodium, alkyl sulfate, alkyl polyoxyethylene sulfate, alkyl phosphate, alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkylbenzyl. Cationic surfactants such as dimethylammonium salt, alkylpyridinium chloride, benzalkonium chloride, polyoxyethylene-polyoxypropylene condensate, polyoxyethylene alkyl ether, alkyl polyglucoside, alkyl monoglyceryl ether, sorbitan fatty acid ester, Polyoxyethylene sorbitan fatty acid ester, lauric acid diethanolamide, oleic acid diethanolamide, stearic acid diethanolamide, glycerin fat Nonionic surfactants such as acid esters, sucrose fatty acid esters, polyoxyethylene alkylphenyl ethers, lauryl dialkylaminoacetic acid betaines, stearyl dialkylaminoacetic acid betaines, dodecylaminomethyldialkylsulfopropylbetaines, hexadecylaminomethyldialkylsulfopropyl Betaine, octadecylaminomethyldialkylsulfopropylbetaine, cocamidopropylbetaine, cocamidopropylhydroxysultain, alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, sodium lauroylglutamate, potassium lauroylglutamate, lauroylmethyl-β -Of alanine, lauryldimethylamine N-oxide, oleyldimethylamine N-oxide Such zwitterionic surfactants can be mentioned. By using these together with the hydrophilic compound (B), the hydrophilicity, antifogging property and water resistance of the resulting coating film are further improved. Among these surfactants, among these, particularly when a surfactant having a long chain alkyl group having 10 or more carbon atoms and / or a surfactant having a fluorine atom in the molecule is used, Since elution into water tends to be suppressed, it is more preferable from the viewpoint of water resistance.

  Examples of the crosslinking reaction catalyst and / or curing catalyst include dialkyltin dicarboxylates such as dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin diacetate, tin oxide compounds such as dibutyltin oxide, tin 2-ethylhexanoate, and 2-ethyl Metal carboxylates such as zinc hexanoate and cobalt salts, triethylamine, pyridine, methylpyridine, benzyldimethylamine, N, N-dimethylcyclohexylamine, N-methylpiperidine, pentamethyldiethylenetriamine, N, N′-endoethylenepiperazine, And tertiary amines such as N, N′-dimethylpiperazine.

As the light stabilizer, for example, a hindered amine light stabilizer is preferably used. Among these, a radical polymerizable light stabilizer having a radical polymerizable double bond in the molecule is preferable. Moreover, as an ultraviolet absorber, an organic type ultraviolet absorber can be used, for example. As the organic ultraviolet absorber, for example, a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, and a triazine ultraviolet absorber can be used. Among these, it is preferable to use a radical polymerizable ultraviolet absorber having a radical polymerizable double bond in the molecule. Also preferred are benzotriazole ultraviolet absorbers and triazine ultraviolet absorbers, which have a high ultraviolet absorbing ability. In addition, it is preferable to use a light stabilizer together with an organic ultraviolet absorber. By using both in combination, the weather resistance of the coating film formed from the coating composition can be improved. In addition, various additive components such as these organic ultraviolet absorbers and light stabilizers may be simply blended with the component (A) and the component (D), or coexist when the component (D) is synthesized. May be.
These optional components are not particularly limited, but usually 10 masses for component (A) and component (B) and optional component (C) and / or component (D) and / or component (E). Or less, 5 parts by weight or less, or 3 parts by weight or less.

The base material is positioned as an object to which particularly excellent antifogging properties and antifogging durability are imparted by the coating layer. Various materials can be employed as the base material. In one embodiment, the substrate is preferably made of resin. Although it does not specifically limit as said resin-made base materials, For example, organic base materials, such as a synthetic resin and a natural resin, can be mentioned.
As the synthetic resin, a thermoplastic resin and a curable resin (such as a thermosetting resin, a photocurable resin, and a moisture curable resin) can be used. More specifically, for example, silicone resin, acrylic resin, methacrylic resin, fluororesin, alkyd resin, aminoalkyd resin, vinyl resin, polyester resin, styrene-butadiene resin, polyolefin resin, polystyrene resin, polyketone resin, polyamide resin, polycarbonate Resin, polyacetal resin, polyether ether ketone resin, polyphenylene oxide resin, polysulfone resin, polyphenylene sulfone resin, polyether resin, polyvinyl chloride resin, polyvinylidene chloride resin, urea resin, phenol resin, melamine resin, epoxy resin, urethane Examples thereof include resins and silicone-acrylic resins. However, it is not limited to the above.
The natural resin is not particularly limited, and examples thereof include cellulose resins, isoprene resins such as natural rubber, and protein resins such as casein.
In one embodiment, the surface of the resin plate may be subjected to a surface treatment such as a corona discharge treatment, a flame treatment, or a plasma treatment, but these surface treatments are not essential.
The type and thickness of the substrate used and the thickness of the film formed by the surface treatment are not particularly limited, and can be appropriately set according to the application.

Production of Coating Composition In an exemplary embodiment, a coating composition for forming a coating film according to the present invention comprises the steps of mixing (A) component and (B) component with water, and then mixing with water; and It can be produced by a method including a step of stirring at 40 ° C. or lower for 10 minutes or more. In general, when manufacturing a coating composition containing water, a method of mixing each component contained in the coating composition after dilution with water, a method of mixing each component in water, and after mixing each component in advance And a method of diluting with water. In this invention, it is preferable to mix (A) component and (B) component previously. By mixing in advance, the component (A) and the component (B) can form a strong interaction. A coating film obtained from the coating composition thus prepared is preferable because of its excellent water resistance. Furthermore, the coating composition which (A) component and (B) component disperse | distributed uniformly can be formed by stirring for 10 minutes or more at less than 40 degreeC. Mixing at 25 ° C. or less and mixing for 1 hour or more is more preferable because the component (A) and the component (B) form a stable dispersion, the silica surface coverage is increased, and the film formability is improved. . A coating film obtained from the coating composition thus prepared is preferable because of its high transparency and excellent appearance.

Production of Coating Film A coating film according to one embodiment is, for example, coated on a substrate with a coating composition (sometimes abbreviated as “water dispersion”) dispersed in a solvent such as water and dried. Can be formed. The viscosity of the aqueous dispersion is preferably 0.1 to 100,000 mPa · s at 20 ° C., and preferably 1 to 10,000 mPa · s (measured with a vibration viscometer). Examples of coating methods that can be used include spraying, flow coating, roll coating, brush coating, dip coating, spin coating, screen printing, casting, gravure printing, and flexographic printing. It is. In addition, the composite of a base material and a coating film, for example, after drying a coating film on a base material, it is preferably 20 ° C. to 500 ° C., more preferably 40 ° C. to 250 ° C. Etc. may be formed.
In one embodiment, after coating the coating composition on a substrate, heat treatment is performed at a temperature of 50 ° C. to 120 ° C. for 10 minutes to 15 minutes as a first drying process, and 70 ° C. to 120 ° C. as a second drying process. It is preferable to perform heat treatment at a temperature of 10 ° C. or lower for 10 to 30 minutes from the viewpoints of adhesion to the substrate, appearance, and scratch resistance. The temperature of the heat treatment in the first drying process is more preferably 50 ° C. or more and 80 ° C. or less from the viewpoint of the appearance of the coating film. The temperature of the heat treatment in the second drying process is preferably 100 ° C. or less, more preferably 80 ° C. or less, from the viewpoint of productivity and applicable substrate types.
Desirable characteristics by XPS elemental analysis on the surface of the coating film thus formed are as described above in relation to the component (B).

The thickness of a coating film becomes like this. Preferably it is 0.1-100 micrometers, More preferably, it is 0.2-10 micrometers. From the viewpoint of transparency, the coating film is preferably 100 μm or less, and in order to exhibit functions such as weather resistance and antifouling properties, it is preferably 0.1 μm or more. In one embodiment, the “coating film” is not necessarily a continuous film, and may be a discontinuous film, an island-shaped dispersion film, or the like. In one embodiment, the thickness of the coating film is 0.1-50 μm, 0.1-10 μm, 0.2-100 μm, 0.2-50 μm, 0.5-100 μm, 0.5-50 μm, 0.5 It may be 10 μm, 1 to 100 μm, 1 to 50 μm, or 1 to 10 μm.
In addition, the coating film of the present invention has good film formability even when the film thickness exceeds 1 μm, has excellent antifogging properties, and is sustainable even when exposed to high temperatures and high humidity. An antifogging coating film can be provided. In a preferred embodiment, the coating film of the present invention has good film formability even when the film thickness exceeds 3 μm, is excellent in antifogging property, and is antifogging even when exposed to high temperature and high humidity. A sustainable anti-fog coating can be provided. In a more preferred embodiment, the coating film of the present invention has good film formability even when the film thickness exceeds 4 μm, has excellent antifogging properties, and is antifogged even when exposed to high temperature and high humidity. It can provide an anti-fogging coating that is sustainable.

EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to a following example, unless the summary is exceeded. The subject matter of the present invention can only be determined by the appended claims, and includes modifications, equivalents, and the like obvious to those skilled in the art in addition to the wording scope.
Various physical properties were evaluated by the following methods.
<Number average particle diameter>
The sample was appropriately diluted by adding a solvent so that the solid content in the sample was 1 to 20% by mass, and the measurement was performed using a wet particle size analyzer (Microtrac UPA-9230 manufactured by Nippon Nikkiso).

<Water contact angle>
After placing a drop of deionized water on the coating film and leaving it at 23 ° C. for a certain period of time, using a contact angle measurement device (CA-X150 contact angle meter, manufactured by Kyowa Interface Science, Japan) The change in contact angle was measured.
・ Water contact angle (°): water drop on deionized water on coating film, water contact angle after 0.1 seconds ・ Saturated water contact angle (°): water drop on deionized water on coating film, 5 Water contact angle after 2 seconds ・ Change in water contact angle: water contact angle (°) / saturated water contact angle (°)

<Appearance of coating film>
The appearance of the obtained coating film was visually evaluated as follows.
A: Transparent with no cracks or cracks.
○: There are no cracks or cracks, but some are cloudy.
X: There are cracks and cracks.

<Adhesion test (cross cut test)>
About the obtained coating film, it evaluated as follows by the cross-cut test of 100 square of 1 mm square by the method based on JIS-K5600-5-6.
○: No peeling.
Δ: Peeling is less than 50%.
X: Peeling is 50% or more.

<Anti-fogging test>
Place the test piece of the obtained coating film at a height of 5 cm from the water surface of the warm water bath maintained at 80 ° C. so that the coating surface faces down, and continuously irradiate the coating film with steam from the hot water bath Then, the presence or absence of fogging 30 seconds after the irradiation was visually evaluated as follows. In addition, if evaluation is more than (triangle | delta), there is no practical problem, and if it is (circle), it is more preferable.
○: Not fogged at all.
(Triangle | delta): Although there is no cloudiness, a water film is non-uniform | heterogenous and visibility is inferior.
X: Cloudy.

<Abrasion resistance>
The state of the coating film when the coating film surface was rubbed once with Kimwipe was observed with a digital microscope and evaluated as follows.
○: Neither scratch nor peeling.
(Triangle | delta): Although there is no peeling, there exists a damage | wound.
X: The coating film is peeled off.

<XPS measurement>
The relative element concentration on the coating film surface was measured by XPS (ULVAC-PHI Verasa probe II). The excitation source is mono. The measurement was performed with AlK. (15 kV × 0.3 mA), analysis size of about 200 mmφ, and photoelectron extraction angle of 45 °.
The capture area is Survey scan: 0 to 1,100 eV
Narrow scan: C1s, O1s, Si2p, N1s,
Pass Energy
Survey scan: 188 eV
Narrow scan: 47 eV
The element concentration ratio (C1s / M) of the C element and the metal element obtained from the C1s spectrum and the metal (M) spectrum derived from the metal oxide (silica) and the carbon-oxygen bond, carbon-nitrogen bond-derived The relative element concentration (atomic%) of C element was determined.
In the C1s peak separation, the full width at half maximum of each component was set to be the same.

<Moisture resistance test>
The prepared coating film was exposed to an environment of 85 ° C. and 85% RH for 24 hours, and then allowed to stand in an environment of 23 ° C. and 50% RH for 1 hour. The resulting coating film was evaluated for coating film appearance, adhesion, water contact angle, and antifogging property.

<Synthesis Example 1 (Synthesis of Polymer Particle (D) Aqueous Dispersion)>
Into a reactor having a reflux condenser, a dropping tank, a thermometer, and a stirring device, 1600 g of ion-exchanged water and 4 g of dodecylbenzenesulfonic acid were added, and then the temperature was heated to 80 ° C. with stirring. To this, a mixture of 185 g of dimethyldimethoxysilane and 117 g of phenyltrimethoxysilane was dropped over about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C., and then the temperature in the reaction vessel was 80 ° C. And stirring was continued for about 1 hour. Next, a mixed solution of 86 g of butyl acrylate, 133 g of phenyltrimethoxysilane, 1.3 g of 3-methacryloxypropyltrimethoxysilane, 137 g of N, N-diethylacrylamide, 3 g of acrylic acid, a reactive emulsifier (trade name “ADEKA rear soap” SR-1025 ", manufactured by Asahi Denka Co., Ltd., 25% solid content aqueous solution), a mixed solution of ammonium persulfate 2% by weight aqueous solution 40 g, and ion-exchanged water 1900 g, in a state where the temperature in the reaction vessel was maintained at 80 ° C. At about 2 hours. Further, stirring was continued for about 2 hours in a state where the temperature in the reaction vessel was 80 ° C., then cooled to room temperature, filtered through a 100-mesh wire mesh, and the solid content was adjusted to 10.0% by mass with ion-exchanged water. A polymer particle (D) aqueous dispersion having a number average particle diameter of 85 nm was obtained.

[Example 1]
40.0 g of water-dispersed colloidal silica (trade name “Snowtex-OXS”, manufactured by Nissan Chemical Industries, Ltd., solid content 10% by mass) as a metal oxide (A) with a hydrophilic compound B), polyoxyethylene-oxypropylene-oxyethylene triblock copolymer previously heated to 50 ° C. (trade name “P123”, manufactured by Sigma-Aldrich Japan, solid content: 100% by mass, density: 1.1 g / cm ³ , average After slowly mixing 40 g (particle diameter 2.1 nm), the mixture was stirred for 1 hour while cooling with water so that the temperature of the mixture became 25 ° C. Thereafter, 213 g of distilled water was mixed, and the mixture was further stirred at 25 ° C. for 1 hour to obtain a coating composition having a solid content of 15%. The obtained coating composition was coated on a polycarbonate plate (manufactured by Takiron Co., Ltd.) having a length of 60 mm, a width of 60 mm, and a thickness of 2 mm using a bar coater # 65, and dried in an environment of 20 ° C. for 30 minutes. Then, the test board was obtained by drying for 30 minutes at 80 degreeC. The film thickness of the obtained coating film was 5 μm. The appearance of the coating film was good (no cracks and transparent). The water contact angle was 45 ° and the water contact angle change was 1.6. The element concentration ratio (C1s / Si) between the C element and the Si element obtained from the C1s spectrum and silica-derived Si spectrum in elemental analysis by XPS on the surface is 11, C1s spectrum derived from carbon-oxygen bond and carbon-nitrogen bond The relative elemental concentration of C element obtained from the above was 43 atomic%. The obtained test piece was placed in an environmental tester with a temperature of 85 ° C. and 85% RH for 24 hours, and then allowed to stand in an environment with a temperature of 23 ° C. and 50% RH for 1 hour. As a result of evaluating the contact angle and antifogging property, the coating film appearance was good, the water contact angle (one of hydrophilicity indices) and antifogging property were maintained, and the moisture resistance was generally good. Table 1 shows the blending amount (parts by mass) of each component of the coating composition. Table 2 shows the evaluation results including the initial characteristics.

[Examples 2 to 4 and Comparative Examples 1 to 4]
In Examples 2 to 4 and Comparative Examples 1 to 4, as shown in Tables 1 and 3, the coating composition was prepared in the same manner as in Example 1 except that the type and amount (parts by mass) of the components were changed. The coating film test piece was manufactured and the coating film performance was evaluated. The evaluation results of the coating film performance including the initial characteristics are shown in Tables 2 and 4.

[Comparative Example 5]
40.0 g of water-dispersed colloidal silica (trade name “Snowtex-OXS”, manufactured by Nissan Chemical Industries, Ltd., solid content 10 mass%) having a number average particle size of 4 nm as the metal oxide (A), hydrophilic compound (B ), Polyoxyethylene-oxypropylene-oxyethylene triblock copolymer (trade name “P123”, manufactured by Sigma-Aldrich Japan, solid content 100 mass%, density 1.1 g / cm ³ , average particle size 2.1 nm) 40 After mixing 0.0 g, the mixture was stirred at 50 ° C. for 1 hour. Thereafter, 17.3 g of distilled water was mixed and stirred at 50 ° C. for 10 minutes. The coating composition after stirring was remarkably thickened and film formation was impossible. Table 3 shows the blending amount (parts by mass) of each component of the coating composition (coating material) of Comparative Example 5.

[Comparative Example 6]
40.0 g of water-dispersed colloidal silica (trade name “Snowtex-OXS”, manufactured by Nissan Chemical Industries, Ltd., solid content 10 mass%) having a number average particle size of 4 nm as the metal oxide (A), hydrophilic compound (B ), Polyoxyethylene-oxypropylene-oxyethylene triblock copolymer (trade name “P123”, manufactured by Sigma-Aldrich Japan, solid content 100 mass%, density 1.1 g / cm ³ , average particle size 2.1 nm) 40 After mixing 0.0 g, the mixture was stirred at 25 ° C. for 1 hour. Thereafter, 356.0 g of distilled water was mixed, followed by stirring at 25 ° C. for 1 hour. The coating composition after stirring (distilled water concentration 98%; solid content concentration 2%) had low film forming property and could not be formed on a substrate. Table 3 shows the blending amounts (parts by mass) of the components of the coating composition (coating material) of Comparative Example 6.

Each reference number noted in Table 1 means the following.
1) STOXS: manufactured by Nissan Chemical Industries, Snowtex-OXS, solid content 10% by mass, acidic type, number average particle diameter 4 nm
2) STO: Nissan Chemical Industries, Snowtex-O, solid content 20% by mass, acidic type, number average particle size 15 nm
3) P123: Sigma-Aldrich Japan, solid content 100% by mass
4) Polyisocyanate A: manufactured by Asahi Kasei Corporation, WT30-100, solid content: 100% by mass

The reference numbers noted in Table 3 mean the following:
5) L44: manufactured by ADEKA Corporation, Pluronic L-44, solid content: 100% by mass
6) PEG4000: manufactured by Tokyo Chemical Industry Co., Ltd., polyethylene glycol 4,000, solid content 100% by mass

  Since Comparative Example 1, Comparative Example 5, and Comparative Example 6 were difficult to form a film on a base material, various coating film physical properties were not evaluated.

<Evaluation results>
As is apparent from Tables 2 and 4, Examples 1 to 4, which are the coating films of the present invention, had excellent coating film performance in all of the coating film appearance, antifogging properties, and moisture resistance. In particular, in Example 3 in which the curing agent (C) was blended, the scratch resistance and the adhesion of the coating film after the moisture resistance test to the substrate were further improved. In Example 4 in which the polymer particles (D) were blended, the adhesion of the coating film after the moisture resistance test to the substrate was further improved. On the other hand, when the coating composition consisting only of colloidal silica of Comparative Example 1 was used, the coating film could not be obtained due to poor wettability to the substrate and film formability. When the amount of the hydrophilic compound relative to the colloidal silica was not sufficient as in Comparative Example 2 and Comparative Example 3, the film formability was low and cracks occurred at a film thickness exceeding 1 μm, and the appearance was poor. The coating film prepared using PEG 4000 of Comparative Example 4 as the hydrophilic compound has a weak film-formability and appearance because the interaction between the colloidal silica and the hydrophilic compound is weak and the hydrophilic compound is not immobilized on the colloidal silica surface. Both moisture resistance was very bad. When the composition was mixed and stirred at 50 ° C. as in Comparative Example 5, significant thickening and aggregation of the composition occurred and film formation was impossible. When the solid content concentration in the composition was 2% by mass as in Comparative Example 6, the wettability to the substrate was poor and film formation was impossible.

The coating film of the present invention is excellent in thick film formability, coating film appearance, hydrophilicity, and antifogging property, and can maintain the antifogging property for a long time even under a severe environment such as high temperature and high humidity. Therefore, the coating film of the present invention can be particularly suitably used as an antifogging coating film that requires high antifogging properties. Furthermore, it can be used for applications requiring anti-fogging durability in a high humidity environment, for example, as a coating film for automotive exterior parts such as vehicle lamps such as automobile headlamps. Moreover, the coating film of this invention can be used also for components which cannot be taken out easily in order to remove fogging, such as internal components of various devices and components installed at high places. All of the features and advantages described above for the coating film according to the present invention also apply to these anti-fogging coating films, coating films for automobile exterior parts, and coating films for internal parts.

Claims (8)

  Element concentration of C element and metal element obtained from C1s spectrum and metal oxide-derived metal (M) spectrum in elemental analysis by XPS, including metal oxide (A) and hydrophilic compound (B) A coating film having a ratio (C1s / M) of 10 or more.   The coating film according to claim 1, wherein the water contact angle value is 40 ° or more and the water contact angle change value is 1 or more and 3 or less.   The coating film according to claim 1 or 2, wherein a relative element concentration of C element obtained from a C1s spectrum derived from carbon-oxygen bond and / or carbon-nitrogen bond in elemental analysis by XPS on the surface is 5 atomic% or more.   The coating film according to any one of claims 1 to 3, wherein the metal oxide (A) is colloidal silica.   5. The coating according to claim 1, wherein the hydrophilic compound (B) is bonded to the surface of the metal oxide through a non-covalent bond and / or a covalent bond. film.   The coating film according to any one of claims 1 to 5, further comprising an isocyanate compound (C).   The coating film according to any one of claims 1 to 6, further comprising polymer particles (D). A metal oxide (A), a hydrophilic compound (B), and, optionally, an isocyanate compound (C) and / or polymer particles (D) and / or water, and any one of claims 1 to 7. 2. A coating composition for producing the coating film according to item 1.