JP2007031648A - Coated film and coated product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated film having excellent stain resistance, transparency, weather resistance and frost damage resistance, and a coated product having the coated film. <P>SOLUTION: The coated film 10 comprising a copolymer 11 and silica particles 12 has ≥30 nm thickness of a silica particle layer formed on the most surface layer of the coated film 10. Preferably, the coated film contains 0.5-20 pts.mass of the silica particles based on 100 pts.mass of the copolymer, and the average particle diameter of the silica particles is 1-60 nm. The copolymer preferably contains 0.1-20 mass% of a unit derived from a hydrolyzable silyl group-containing radically polymerizable monomer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coating film and a coated article having the coating film.

In recent years, in the paint field, conversion from organic solvent-based paints to water-based paints has been attempted from the viewpoint of environmental protection and safety and health. However, water-based paints have low coating properties such as weather resistance, water resistance, frost resistance, and stain resistance, particularly stain resistance compared to solvent systems, and there are many problems to be solved. .
Various developments of water-based paints and methods for laminating coating films have been made for the purpose of solving these problems. For example, as a resin for water-based paints, an emulsion of an acrylic resin by emulsion polymerization has attracted attention because it has a feature that the resulting coating film has relatively good weather resistance and the like. In addition, the water-based emulsion for undercoat, water-based emulsion for intermediate-coat, and water-based emulsion for top-coat are each given performance, and these water-based emulsions are sequentially layered to show the coating properties such as stain resistance as a whole. The idea to do is made.

As a method of improving the stain resistance of the coating film, (i) a method of increasing the hardness of the coating film (increasing the glass transition temperature (Tg) of the resin), (ii) hydrophilizing the coating film surface, and using rainwater Examples thereof include a method for imparting a self-cleaning action for washing away contaminants, and (iii) a method for controlling the chargeability of the coating film to suppress the adhesion of dirt due to static electricity.
However, the method (i) has a problem that the film-forming property is lowered, the coating film is cracked in winter, and the frost damage resistance is problematic. In addition, it is difficult to greatly improve the stain resistance of the coating film.
Examples of the method (ii) include a method using a resin containing a monomer unit having hydrophilicity, and adding a surfactant or the like. However, a resin containing a monomer unit having hydrophilicity has a problem of low weather resistance. Moreover, when surfactant etc. are added, the water resistance of a coating film falls and there exists a problem in sustaining the effect of stain resistance.
In the method (iii), the addition of the antistatic agent adversely affects the weather resistance and water resistance of the coating film, and there is a problem in the sustainability of the effect.

As an aqueous paint for solving these problems, an aqueous paint containing an inorganic substance is known. For example, Patent Document 1 proposes a coating composition in which colloidal silica is contained in an aqueous emulsion containing a copolymer of vinylsilane and an acrylic monomer. And it is supposed that the coating film which consists of this coating composition is excellent in heat resistance, water resistance, and adhesiveness.
However, this coating composition requires a large amount of colloidal silica having a solid content of 500 to 20000 parts by mass with respect to 100 parts by mass of the solid content of the aqueous emulsion. When a large amount of colloidal silica is used, there are problems that transparency of the coating film, weather resistance, storage stability of the coating composition, and coating workability are poor.

On the other hand, the following water-based paints have been proposed as water-based paints using a relatively small amount of colloidal silica (Patent Documents 2 and 3).
Patent Document 2 contains 100 parts by mass of a polyorganosiloxane-based graft copolymer emulsion obtained by graft copolymerization of 10 to 90% by mass of an unsaturated vinyl monomer with respect to polyorganosiloxane, and 1 to 50 parts by mass of colloidal silica. Flame retardant coating materials have been proposed. And it is supposed that the coating film which consists of this flame-retardant coating material is excellent in a flame retardance, extensibility, adhesiveness, a temperature-sensitive characteristic, moisture permeability, and stain resistance.
However, this coating material contains 52 parts by mass or more of the polyorganosiloxane component in 100 parts by mass of the solid content of the polyorganosiloxane-based graft block copolymer emulsion, and contains a large amount of the water-repellent silicone component. Therefore, the hydrophilicity of the coating film becomes insufficient, and the stain resistance is low. There is also a problem in terms of transparency and hardness of the coating film.

Patent Document 3 proposes an aqueous coating composition containing 100 parts by mass of a polyorganosiloxane-based graft copolymer emulsion and 1 to 300 parts by weight of colloidal silica. The aqueous coating composition is excellent in storage stability, and the coating film is excellent in hardness, water resistance, and stain resistance.
The coating film made of the aqueous coating composition is significantly improved in stain resistance as compared with the coating film made of the coating material described in Patent Document 2, but it is desired to further reduce contamination by making the coating film hydrophilic. It has been.

In Patent Documents 4 and 5, etc., in the surface coating of cementitious materials, a multi-layer structure of undercoat, intermediate coat, and topcoat is formed, and silicate or silica sol is blended in all of them to prevent static accumulation of the laminated coating film. Thus, it is described that contamination due to static electricity is prevented and stain resistance is imparted to the coating film.
However, if any one of the undercoating, intermediate coating, and topcoating is a resin-only coating film, there is a problem that static electricity stays and stains adhere to the coating film.
JP-B-1-41180 JP-A-4-23857 JP-A-9-165554 Japanese Patent Publication No.53-34141 JP-A-5-96234

  An object of the present invention is to provide a coating film excellent in stain resistance, transparency, weather resistance, and frost damage resistance.

The coating film of the present invention is a coating film containing a copolymer and silica particles, and the thickness of the layer made of silica particles formed on the outermost layer of the coating film is 30 nm or more. Features.
In the coating film of this invention, it is preferable to contain 0.5-20 mass parts of silica particles with respect to 100 mass parts of said copolymers.
The average particle diameter of the silica particles is preferably 1 to 60 nm.
The copolymer preferably contains 0.1 to 20% by mass of a unit derived from a hydrolyzable silyl group-containing radical polymerizable monomer in the copolymer (100% by mass).
The coated article of the present invention has the coating film of the present invention.

The coating film of the present invention is excellent in stain resistance, transparency, weather resistance, and frost damage resistance.
The coated product of the present invention is excellent in stain resistance, transparency, weather resistance, and frost damage resistance of the coating film.

<Coating film>
FIG. 1 is a transmission electron microscope (hereinafter referred to as TEM) observation image showing an example of a cross section of the coating film of the present invention, and FIG. 2 is a schematic diagram thereof.
The coating film 10 is a coating film containing the copolymer 11 and the silica particles 12, and a silica particle layer 13 composed of the silica particles 12 unevenly distributed therein is formed on the outermost layer of the coating film 10. Yes.

(Silica particle layer)
The silica particle layer 13 is a layer composed of silica particles 12 unevenly distributed in the outermost layer of the coating film 10, and the copolymer 11 may exist in the gap between the silica particles 12.
The thickness a of the silica particle layer 13 is preferably 30 nm or more and 1300 nm or less, more preferably 1100 nm or less, and still more preferably 1000 nm or less. By setting the thickness a of the silica particle layer 13 to 30 nm or more, sufficient contamination resistance (hydrophilicity, antistatic property) can be obtained. Moreover, it exists in the tendency for the whitening of a coating film to be reduced by the thickness a of the silica particle layer 13 being 1300 nm or less.

  The thickness a of the silica particle layer 13 is obtained from a TEM observation image of the cross section of the coating film 10. Specifically, using image processing software such as Adobe Photoshop (manufactured by Adobe), the surface of the coating film 10 of the TEM observation image is aligned with the horizontal direction of the display screen, and the coating film 10 is divided into six equal parts. 5 perpendicular lines are drawn, and the length (nm) of each perpendicular crossing the silica particle layer 13 is calculated by comparing with the length of the scale bar of the TEM observation image, and the average value of these is calculated. Thickness a. The interval between the perpendiculars is preferably 100 nm or more.

(Silica particles)
Silica particles are components that exhibit sufficient stain resistance by imparting hydrophilicity and electrostatic properties to the coating film. Moreover, it is a component which provides hardness and weather resistance to a coating film.

  0.5-20 mass parts is preferable with respect to 100 mass parts of copolymers, and, as for the quantity of a silica particle, 1-18 mass parts is more preferable. By making the amount of silica particles 0.5 parts by mass or more, the stain resistance (hydrophilicity, antistatic property) of the coating film is improved. By making the amount of silica particles 20 parts by mass or less, the stain resistance (hydrophilicity, antistatic property) of the coating film is reduced without reducing the transparency, weather resistance, water resistance, and frost damage resistance of the coating film. improves. Moreover, whitening of a coating film is suppressed by making the quantity of a silica particle into 20 mass parts or less.

  The average particle size of the silica particles is preferably 1 to 60 nm, more preferably less than 40 nm, and even more preferably less than 20 nm. By making the average particle diameter of the silica particles 60 nm or less, the silica particles easily float on the surface layer of the coating film during the formation of the coating film, and the silica particles closely fill the copolymer particle gap in the surface layer of the coating film. In addition, a silica particle layer is formed with a thickness, and the copolymer, silica particles, and silica particles are chemically bonded or physically adsorbed to be present in the outermost layer of the coating film, thereby exhibiting stain resistance. The Moreover, by making the average particle diameter of the silica particles 60 nm or less, it is possible to suppress irregular reflection of light on the surface of the coating film and to prevent the coating film from appearing white. The average particle diameter of the silica particles is calculated using an image processing software, and 10 points are calculated from the TEM observation image of the silica particles by comparing the particle diameter of the silica particles with the length of the scale bar of the TEM observation image. Calculated by taking

Silica particles may be surface-treated with a silane compound represented by the following general formula (1).
SiR ¹ _{n + 1} (OR ² ) _3-n (1)
(In the formula, R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, R ² represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms which may contain an ether bond, n represents an integer of 0 to 2.)

  Examples of the silane compound represented by the general formula (1) include trimethoxysilane, dimethoxysilane, dimethoxydimethylsilane, methoxytrimethylsilane, triethoxysilane, diethoxymethylsilane, dimethylethoxysilane, phenyltrimethoxysilane, and dimethoxyphenylsilane. , Phenyltriethoxysilane, diethoxyphenylsilane and the like. These may be used alone or in combination of two or more. Of these, trimethoxymethylsilane is particularly preferred.

  As a method for surface-treating silica particles with a silane compound, (i) a method in which colloidal silica and a silane compound are added to an aqueous dispersion of a copolymer, and the mixture is stirred for an arbitrary time in a temperature range from room temperature to 100 ° C .; ii) Add silica particles surface-treated with a silane compound obtained by stirring colloidal silica and a silane compound in a temperature range of room temperature to 100 ° C. for an arbitrary time in an aqueous dispersion of the copolymer. Methods and the like.

  1-60 mass parts is preferable with respect to 100 mass parts of silica particles, and, as for the quantity of a silane compound, 5-40 mass parts is more preferable. By setting the amount of the silane compound to 1 part by mass or more, the weather resistance of the coating film is improved. By adjusting the amount of the silane compound to 60 parts by mass or less, the weather resistance of the coating film can be further improved without lowering the storage stability of the aqueous coating composition, the stain resistance of the coating film, and the water resistance. .

(Copolymer)
The copolymer is a film forming component, and is a component that imparts film forming properties, weather resistance, water resistance, frost damage resistance, and the like to the coating film.
Examples of the copolymer include polyester resins, polyurethane resins, acrylic resins, acrylic silicon resins, and fluorine resins. Of these, acrylic resins and acrylic silicon resins are preferable, and acrylic silicon resins are more preferable from the viewpoint of stain resistance, weather resistance, water resistance, and frost damage resistance of the coating film.

  Examples of the radical polymerizable monomer constituting the acrylic resin and the acrylic silicon resin include vinyl silanes such as vinyl methyl dimethoxy silane, vinyl trimethoxy silane, vinyl triethoxy silane, vinyl methyl dichloro silane, and vinyl trichloro silane; γ-acryloyloxyethylmethyldimethoxysilane, γ-acryloyloxyethyltrimethoxysilane, γ-acryloyloxyethyltriethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-acryloyloxypropyl Triethoxysilane, γ-acryloyloxyethylmethyldichlorosilane, γ-acryloyloxyethyltrichlorosilane, γ-acryloyloxypropylme Acryloyloxyalkylsilanes such as rudichlorosilane, γ-acryloyloxypropyltrichlorosilane; γ-methacryloyloxyethylmethyldimethoxysilane, γ-methacryloyloxyethyltrimethoxysilane, γ-methacryloyloxyethyltriethoxysilane, γ-methacryloyloxypropyl Methyldimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-methacryloyloxyethylmethyldichlorosilane, γ-methacryloyloxyethyltrichlorosilane, γ-methacryloyloxypropylmethyldichlorosilane, γ- Methacryloyloxyalkylsilanes such as methacryloyloxypropyltrichlorosilane;

  Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, sec-butyl (meth) Acrylate, t-butyl (meth) acrylate, n-amyl (meth) acrylate, i-amyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, Alkyl (meth) acrylates having an alkyl group having 1 to 18 carbon atoms such as nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; cyclohexyl ( Meta) Cycloalkyl (meth) acrylates such as acrylate and pt-butylcyclohexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4 Hydroxyl group-containing radical polymerizable monomers such as hydroxybutyl (meth) acrylate and glycerol mono (meth) acrylate; hydroxypolyethylene oxide mono (meth) acrylate, hydroxypolypropylene oxide mono (meth) acrylate, hydroxy (polyethyleneoxide- Polypropylene oxide) mono (meth) acrylate, hydroxy (polyethylene oxide-propylene oxide) mono (meth) acrylate, hydroxy (polyethyleneoxy) Polytetramethylene oxide) mono (meth) acrylate, hydroxy (polyethylene oxide-tetramethylene oxide) mono (meth) acrylate, hydroxy (polypropylene oxide-polytetramethylene oxide) mono (meth) acrylate, hydroxy (polypropylene oxide-tetramethylene Oxide) mono (meth) acrylate, methoxypolyethylene oxide mono (meth) acrylate, lauroxypolyethylene oxide mono (meth) acrylate, stearoxypolyethylene oxide mono (meth) acrylate, allyloxypolyethylene oxide mono (meth) acrylate, nonylphenoxypoly Ethylene oxide mono (meth) acrylate, nonylphenoxypolypropylene oxide mono (meth) acrylate, Polyoxyalkylene group-containing (meth) acrylates such as octoxy (polyethylene oxide-polypropylene oxide) mono (meth) acrylate and nonylphenoxy (polyethylene oxide-propylene oxide) mono (meth) acrylate;

  Hydroxycycloalkyl (meth) acrylates such as p-hydroxycyclohexyl (meth) acrylate; lactone-modified hydroxyl group-containing radical polymerizable monomers; 2-aminoethyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylate Aminoalkyl (meth) acrylates such as 2-aminopropyl (meth) acrylate and 2-butylaminoethyl (meth) acrylate; amides such as (meth) acrylamide, N-methylolacrylamide and N-butoxymethyl (meth) acrylamide Group-containing polymerizable monomers: ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, etc. Functional (meth) acrylates; metal-containing radical polymerizable monomers such as zinc diacrylate and zinc dimethacrylate; 2- (2′-hydroxy-5 ′-(meth) acryloxyethylphenyl) -2H-benzo Triazole, 1- (meth) acryloyl-4-hydroxy-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-methoxy-2,2,6,6-tetramethylpiperidine, 1- (Meth) acryloyl-4-amino-4-cyano-2,2,6,6-tetramethylpiperidine and other UV-resistant (meth) acrylates; dimethylaminoethyl (meth) acrylate methyl chloride salt, allyl (meth) Acrylate, glycidyl (meth) acrylate, (meth) acrylonitrile, phenyl (meth) acrylate, benzine Other (meth) acrylic monomers such as (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate; acrolein, diacetone acrylamide , Carbonyl group-containing monomers based on aldehyde groups or keto groups, such as formylstyrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, pivalin aldehyde, diacetone (meth) acrylate, acetonitrile acrylate, acetoacetoxyethyl (meth) acrylate ;

  Aromatic vinyl monomers such as styrene, methylstyrene, chlorostyrene and methoxystyrene; Conjugated diene monomers such as 1,3-butadiene, isoprene and 2-chloro-1,3-butadiene; (meth) acrylic Carboxyl group-containing monomers such as acid, itaconic acid, fumaric acid, maleic acid, half esters thereof, 2- (meth) acryloxyethylphthalic acid, 2- (meth) acryloxyethylhexahydrophthalic acid; vinyl acetate Radical polymerizable monomers such as vinyl chloride, ethylene and vinyl propionate; silicone polymers having a graft crossing agent described later; oxirane group-containing radical polymerizable monomers such as glycidyl (meth) acrylate; N-methylol (meta ) Acrylamide, N-butoxymethyl (meth) acrylamide, N-methoxymethyl Meth) self-crosslinking alkylol or alkoxyalkyl compound of ethylenically unsaturated amide such as acrylamide functional group-containing radical polymerizable monomers.

  The copolymer preferably contains units derived from a hydrolyzable silyl group-containing radical polymerizable monomer from the viewpoint of stain resistance, weather resistance, and water resistance of the coating film. By containing a unit derived from a hydrolyzable silyl group-containing radical polymerizable monomer, the copolymer and the silica particles are easily bound, and the silica particle layer can be made thick. Contamination resistance, weather resistance, and water resistance can be further improved.

  The content of the unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer is preferably 0.1 to 20% by mass, more preferably 0.5 to 18% by mass in the copolymer (100% by mass). Preferably, 1 to 17% by mass is more preferable. By setting the content of the unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer to 0.1% by mass or more, the stain resistance, weather resistance, and water resistance of the coating film are improved. By making the content of the unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer 20 parts by mass or less, stain resistance, weather resistance, water resistance without reducing the frost resistance of the coating film. Can be further improved.

  Examples of the hydrolyzable silyl group-containing radical polymerizable monomer include the aforementioned vinyl silanes, acryloyloxyalkylsilanes, methacryloyloxyalkylsilanes, and the like. Of these, acryloyloxyalkylsilanes and methacryloyloxyalkylsilanes are particularly preferable in consideration of radical polymerization reactivity, contamination resistance, weather resistance, and water resistance.

The copolymer preferably contains a unit derived from a carboxyl group-containing monomer from the viewpoint of storage stability of the aqueous coating composition, blending stability when a pigment and additives are added to form a coating.
0.1-10 mass% is preferable in a copolymer (100 mass%), and, as for content of the unit derived from a carboxyl group-containing monomer, 0.5-8 mass% is more preferable. When the content of the unit derived from the carboxyl group-containing monomer is 0.1% by mass or more, the storage stability of the aqueous coating composition is improved, and when the aqueous coating composition is colored with a pigment, Problems such as the generation of aggregates can be avoided. By making the content of the unit derived from the carboxyl group-containing monomer 10% by mass or less, the storage stability and blending stability of the aqueous coating composition can be improved without lowering the weather resistance and water resistance of the coating film. Further improvement can be achieved.

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, itaconic acid, citraconic acid, maleic acid, monomethyl maleate, monobutyl maleate, monomethyl itaconate, monobutyl itaconate, vinylbenzoic acid, monohydroxy oxalate Ethyl (meth) acrylate, tetrahydrophthalic acid monohydroxyethyl (meth) acrylate, tetrahydrophthalic acid monohydroxypropyl (meth) acrylate, 5-methyl-1,2-cyclohexanedicarboxylic acid monohydroxyethyl (meth) acrylate, phthalic acid mono Hydroxyethyl (meth) acrylate, monohydroxypropyl (meth) acrylate phthalate, monohydroxyethyl (meth) acrylate maleate, hydroxypropyl (meth) acrylate maleate DOO, tetrahydrophthalic acid mono-hydroxybutyl (meth) acrylate. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The copolymer is a hydroxyl group-containing radically polymerizable monomer and / or polyoxy group from the viewpoint of blending stability of the aqueous coating composition, stain resistance of the coating film, weather resistance, water resistance and adhesion to various materials. It is preferable to contain a unit derived from an alkylene group-containing radical polymerizable monomer.

  The content of the unit derived from the hydroxyl group-containing radical polymerizable monomer and the polyoxyalkylene group-containing radical polymerizable monomer is preferably 0.5 to 20% by mass in the copolymer (100% by mass), 1-12 mass% is more preferable. By setting the content of these monomer units to 0.5% by mass or more, the blending stability of the aqueous coating composition, the stain resistance of the coating film, the weather resistance, the water resistance and the adhesion to various materials are improved. . By controlling the content of these monomer units to 20% by mass or less, the blending stability of the aqueous coating composition, the stain resistance of the coating film, and various materials can be achieved without reducing the weather resistance and water resistance of the coating film. The adhesion with respect to can be further improved.

Examples of the hydroxyl group-containing radical polymerizable monomer include hydroxymethyl (meth) acrylate and 6-hydroxyhexyl (meth) acrylate in addition to the above-mentioned hydroxyl group-containing radical polymerizable monomers.
Examples of the polyoxyalkylene group-containing radical polymerizable monomer include the above-mentioned polyoxyalkylene group-containing radical polymerizable monomers (terminal hydroxy type polyoxyalkylene group-containing radical polymerizable monomer, alkyl group terminal type). Polyoxyalkylene group-containing radical polymerizable monomer).
These may be used individually by 1 type and may be used in combination of 2 or more type.

The copolymer preferably contains units derived from t-butyl methacrylate and / or cyclohexyl methacrylate from the viewpoint of the weather resistance and water resistance of the coating film.
The content of units derived from t-butyl methacrylate and cyclohexyl methacrylate is preferably 5 to 70% by mass and more preferably 10 to 60% by mass in the copolymer (100% by mass). By setting the content of these monomer units to 5% by mass or more, the water resistance and weather resistance of the coating film are improved. By setting the content of these monomer units to 70% by mass or less, the weather resistance and water resistance can be further improved without reducing the frost damage resistance of the coating film.

  The copolymer preferably contains a unit derived from a self-crosslinkable functional group-containing radical polymerizable monomer from the viewpoint of stain resistance, weather resistance, water resistance and adhesion to various materials of the coating film. The self-crosslinkable functional group-containing radical polymerizable monomer is chemically stable while the copolymer is dispersed in an aqueous dispersion and stored at room temperature. It refers to a radically polymerizable monomer having a functional group that causes a reaction between side chain functional groups due to other external factors and generates a chemical bond between the side chain groups.

  The content of the unit derived from the self-crosslinkable functional group-containing radical polymerizable monomer is preferably 0.1 to 15% by mass, more preferably 0.5 to 12% by mass in the copolymer (100% by mass). preferable. By setting the content of the unit derived from the self-crosslinkable functional group-containing radical polymerizable monomer to 0.1% by mass or more, the coating film has stain resistance, weather resistance, water resistance and adhesion to various materials. improves. By making the content of the unit derived from the self-crosslinkable functional group-containing radical polymerizable monomer 15% by mass or less, the stain resistance of the coating film is reduced without reducing the water resistance and weather resistance of the coating film. The adhesion to various materials can be further improved.

  Examples of the self-crosslinkable functional group-containing radical polymerizable monomer include the above-mentioned self-crosslinkable functional group-containing radical polymerizable monomer (oxirane group-containing radical polymerizable monomer, ethylol unsaturated amide alkylol or alkoxy). Alkyl compounds). These may be used individually by 1 type and may be used in combination of 2 or more type.

It is preferable that a copolymer contains the unit derived from an ultraviolet-ray radically polymerizable monomer from the point of the weather resistance of a coating film.
0.1-10 mass% is preferable in a copolymer (100 mass%), and, as for content of the unit derived from an ultraviolet-ray radically polymerizable monomer, 0.5-8 mass% is more preferable. The weather resistance of a coating film improves by making content of the unit derived from an ultraviolet-ray radical polymerizable monomer into 0.1 mass% or more. By setting the content of the unit derived from the UV-resistant radical polymerizable monomer to 10% by mass or less, the weather resistance of the coating film can be further improved without lowering the polymerization stability.

Examples of the UV-resistant radical polymerizable monomer include (meth) acrylate having a light stabilizing action and (meth) acrylate having an UV-absorbing component.
Examples of the (meth) acrylate having a light stabilizing action include 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6. -Tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4 -Cyano-4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine and the like.
Examples of the (meth) acrylate having an ultraviolet absorbing component include 2- [2-hydroxy-5- (meth) acryloyloxyethylphenyl] -2H-benzotriazole, 2- [2-hydroxy-3-t-butyl. -5- (meth) acryloyloxyethylphenyl] -2H-benzotriazole, 2- [2-hydroxy-3-t-amyl-5- (meth) acryloyloxyethylphenyl] -2H-benzotriazole, and the like.
These may be used individually by 1 type and may be used in combination of 2 or more type.

  The copolymer is composed of a polymer block (A) having dimethylsiloxane as a repeating unit and a radical polymerizable monomer in order to develop higher stain resistance, weather resistance, water resistance, and frost damage resistance of the coating film. Graft block copolymer comprising a polymer block (B) having a polymer as a repeating unit, and a silicon-containing graft crossover agent unit (C) copolymerized with the polymer block (A) and the polymer block (B) It is preferable that

  The polymer block (A) includes dimethyldialkoxysilanes such as dimethyldimethoxysilane and dimethyldiethoxysilane; hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, tetradeca Dimethylsiloxane cyclic oligomers such as methylcycloheptasiloxane and dimethylcyclics (dimethylsiloxane cyclic oligomer 3-7 mer mixture); so-called polyorganosiloxanes obtained by polymerizing raw materials such as dimethyldichlorosilane. Considering performance and cost such as thermal stability of the resulting graft block copolymer, the raw material for the polymer block (A) is most preferably a dimethylsiloxane cyclic oligomer.

  The mass average molecular weight of the polymer block (A) is preferably 10,000 or more, and more preferably 50,000 or more. This is because if the weight average molecular weight is less than 10,000, the durability of the resulting coating film tends to decrease.

  The content of the polymer block (B) is preferably 50 to 99.7% by mass and more preferably 60 to 99.5% by mass in the graft block copolymer (100% by mass). By setting the content of the polymer block (B) to 50% by mass or more, the hardness, strength and stain resistance of the coating film are improved. By setting the content of the polymer block (B) to 99.7% by mass or less, it tends to be possible to suppress the deterioration of the weather resistance, water resistance and frost damage resistance of the coating film.

  The silicon-containing graft crossing agent unit (C) is a component that ensures the transparency of the resulting coating film. Examples of the silicon-containing graft crossing agent include compounds containing one or more hydrolyzable silyl groups and one or more radically polymerizable functional groups or mercapto groups in the molecule. The hydrolyzable silyl group is preferably an alkoxysilyl group in view of polymerization reactivity, ease of handling, cost, and the like.

  Examples of the silicon-containing grafting agent include the above-mentioned vinyl silanes, acryloyloxyalkyl silanes, methacryloyloxyalkyl silanes; γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, etc. And mercaptoalkylsilanes. Among these, acryloyloxyalkylsilanes, methacryloyloxyalkylsilanes, and mercaptoalkylsilanes are particularly preferable in consideration of reactivity, stain resistance, weather resistance, and water resistance. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The content of the silicon-containing graft crossing agent is preferably from 0.5 to 50 mol%, more preferably from 1 to 15 mol%, based on the total of 100 mol% of silicon atoms in the graft block copolymer. By setting the content of the silicon-containing graft crossing agent to 0.5 mol% or more, the transparency of the coating film is improved. When the content of the silicon-containing graft crossing agent is 50 mol% or less, the coating film performance is improved. Further, when the content of the silicon-containing graft crossing agent is 1 mol% or more, the transparency of the obtained coating film becomes extremely good. In addition, when the content of the silicon-containing graft crossing agent is 15 mol% or less, latex stability during emulsion polymerization is improved.

  Hydrolyzable silyl group-containing radical polymerizable monomer, graft crossing agent, carboxyl group-containing monomer, hydroxyl group-containing radical polymerizable monomer, polyoxyalkylene group-containing radical polymerizable monomer, t- Two or more kinds of butyl methacrylate, cyclohexyl methacrylate, self-crosslinkable functional group-containing radical polymerizable monomer, and UV-resistant radical polymerizable monomer may be used in combination.

  The content of each monomer unit described above in the copolymer can be measured using various apparatuses. For example, gas chromatograph, pyrolysis gas chromatograph, gas chromatograph mass spectrometer, pyrolysis gas chromatograph mass spectrometer, high performance liquid chromatograph, liquid chromatograph, Fourier transform infrared spectrophotometer, nuclear magnetic resonance apparatus, fluorescent X-ray apparatus And an ICP emission analyzer. These may be used individually by 1 type and may be used in combination of 2 or more type. Furthermore, it is possible to perform appropriate pretreatment when using each device.

<Formation method of coating film>
The coating film of the present invention is formed by applying an aqueous coating composition containing a copolymer and silica particles to a substrate or the like and drying.

(Water-based paint composition)
The aqueous coating composition is prepared, for example, by mixing an aqueous dispersion of a copolymer and colloidal silica. The aqueous coating composition preferably contains an anionic surfactant and a nonionic surfactant.
The solid content concentration of the aqueous coating composition is usually 10 to 80% by mass.

(Aqueous dispersion of copolymer)
Examples of the aqueous dispersion of the copolymer include an emulsion obtained by an emulsion polymerization method, a solution obtained by diluting the emulsion with water, a solution obtained by diluting a solution of a copolymer obtained by a solution polymerization method with water, and the like. It is done. Of these, emulsions obtained by emulsion polymerization or those diluted with water are preferred.
The emulsion can be obtained by a known method such as a method of polymerizing a radical polymerizable monomer mixture with a radical polymerization initiator in the presence of a surfactant.

  Examples of the surfactant include known anionic, cationic, or nonionic surfactants and polymer emulsifiers. Further, a so-called reactive emulsifier having a radical polymerizable unsaturated bond in the surfactant component may be used. As the surfactant, an anionic surfactant and a nonionic surfactant described later are preferable. The amount of the surfactant is preferably such that the amount of the anionic surfactant and the nonionic surfactant in the finally obtained aqueous coating composition falls within the range described below.

  Examples of radical polymerization initiators include persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate; azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′- Oil solubility of azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, etc. Azo compounds; 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, 2,2′-azobis {2-methyl-N— [2- (1-hydroxyethyl)] propionamide}, 2,2′-azobis {2-methyl-N- [2- (1-hydroxybutyl)] propionamide 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] and its salts, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] and Its salts, 2,2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] and its salts, 2,2′-azobis {2- [1- (2-hydroxy Ethyl) -2-imidazolin-2-yl] propane} and salts thereof, 2,2′-azobis (2-methylpropionamidine) and salts thereof, 2,2′-azobis (2-methylpropyneamidine) and salts thereof , 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] and salts thereof; benzoyl peroxide, cumene hydropa Oxide, t- butyl hydroperoxide, t- butyl peroxy-2-ethylhexanoate, and organic peroxides such as t-butyl peroxy isobutyrate is. These may be used individually by 1 type and may be used in combination of 2 or more type.

When acceleration of the polymerization rate or low temperature polymerization at 70 ° C. or lower is desired, it is advantageous to use a reducing agent such as sodium bisulfite, ferrous sulfate, ascorbate, Rongalite in combination with the radical polymerization catalyst. is there.
The addition amount of the radical polymerization initiator is usually 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of the radical polymerizable monomer, and 0 in consideration of the progress of polymerization and the control of the reaction. 0.05 to 5 parts by mass is preferable.

  When adjusting the molecular weight of the copolymer, as a molecular weight adjusting agent, mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan, n-hexyl mercaptan; carbon tetrachloride , Halogen compounds such as ethylene bromide; and known chain transfer agents such as α-methylstyrene dimer may be used. The amount of the chain transfer agent is usually 1 part by mass or less with respect to 100 parts by mass of the total amount of the radical polymerizable monomer.

  The emulsion obtained by the emulsion polymerization method can be improved in stability by adding a basic compound to adjust its pH from neutral to weakly alkaline, that is, in the range of about pH 6.5 to 10.0. Examples of the basic compound include ammonia, triethylamine, propylamine, dibutylamine, amylamine, 1-aminooctane, 2-dimethylaminoethanol, ethylaminoethanol, 2-diethylaminoethanol, 1-amino-2-propanol, 2- Amino-1-propanol, 2-amino-2-methyl-1-propanol, 3-amino-1-propanol, 1-dimethylamino-2-propanol, 3-dimethylamino-1-propanol, 2-propylaminoethanol, Examples include ethoxypropylamine, aminobenzyl alcohol, morpholine, sodium hydroxide, potassium hydroxide and the like.

Examples of the particle structure of the copolymer in the emulsion include a single layer structure and a multilayer structure. The copolymer in the emulsion obtained by the multistage emulsion polymerization method has a multilayer structure, and the polymer forming the outermost layer has units derived from hydrolyzable silyl group-containing radical polymerizable monomers. It is preferable.
The unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer is a component for improving the stain resistance, weather resistance and water resistance of the coating film. Reduce. Therefore, it is preferable to improve the stain resistance, weather resistance and water resistance of the coating film in a small amount, and a unit derived from a hydrolyzable silyl group-containing radical polymerizable monomer is introduced into the outermost layer of the multilayer structure particle. This purpose can be achieved. The radical polymerization initiator for copolymerizing the hydrolyzable silyl group-containing radical polymerizable monomer in the outermost layer is preferably a water-soluble azo compound from the viewpoint of stain resistance, weather resistance, and water resistance of the coating film. .

(Colloidal silica)
Colloidal silica is a colloidal liquid in which silica particles are dispersed in a dispersion medium. By using the silica particles as colloidal silica, the silica particles and the copolymer particles continue to maintain dispersion stability in the aqueous coating composition, and when the coating film is formed, the silica particles are interposed between the copolymer particles. It is thought that a silica particle film is formed with a thickness so as to float on the surface of the coating film so as to pass through and cover the copolymer particles.
A commercially available product may be used as the colloidal silica. Colloidal silica may be one using water as a dispersion medium, or one using an organic solvent as a dispersion medium.

As aqueous colloidal silica showing acidity, trade names: Snowtex OXS (SiO ₂ solid content 10 mass%), Snowtex OS (SiO ₂ solid content 20 mass%), Snowtex O (SiO ₂ solid content 20 mass%) , Snowtex O-40 (SiO ₂ solid content 40% by mass), Snowtex OL (SiO ₂ solid content 20% by mass), Snowtex OUP (SiO ₂ solid content 15% by mass) (the above is Nissan Chemical Industries Ltd.) Manufactured), Adelite AT-20Q (Asahi Denka Kogyo Co., Ltd., SiO ₂ solid content 20% by mass), Cataloid SN (Catalyst Chemical Industries, Ltd., SiO ₂ solid content 20% by mass), Silica Doll-20A ( NIPPON CHEMICAL INDUSTRIES, INC., SiO ₂ solid content 20% by mass), Silica Doll-20GA (Nippon Chemical Industry Co., Ltd., SiO ₂ solid content 20% by mass), and the like.

Examples of the aqueous colloidal silica exhibiting alkalinity include, for example, trade names: Snowtex XS (SiO ₂ solid content 20% by mass), Snowtex 20 (SiO ₂ solid content 20% by mass), Snowtex 30 (SiO ₂ solid content 30% by mass). %), Snowtex 40 (SiO ₂ solid content 40% by mass), Snowtex 50 (SiO ₂ solid content 50% by mass), Snowtex C (SiO ₂ solid content 20% by mass), Snowtex N (SiO ₂ solid content) 20% by mass), SNOWTEX S (SiO ₂ solid content 30% by mass), SNOWTEX CM (SiO ₂ solid content 30% by mass), SNOWTEX UP (SiO ₂ solid content 20% by mass), SNOWTEX 20L (SiO ₂ solid content of 20 mass%), Snowtex XL (SiO ₂ solid content: 40 wt%) (or more manufactured by Nissan Chemical Industries, Ltd.), Adelite T-20 (SiO ₂ solid content of 20 mass%), ADELITE AT-20N (SiO ₂ solid content of 20 mass%), ADELITE AT-20A (SiO ₂ solid content of 20 mass%), ADELITE AT-30, ADELITE AT-40 , Adelite AT-50, Adelite AT-30A, Adelite AT-300, Adelite AT-300S (above Asahi Denka Kogyo Co., Ltd.), Cataloid S-20L (SiO ₂ solid content 20% by mass), Cataloid S-20H (SiO ₂ solid content 20% by mass), Cataloid S-30L (SiO ₂ solid content 30% by mass), Cataloid S-30H (SiO ₂ solid content 30% by mass), Cataloid SI-30 (SiO ₂ solid content 30% by mass) ), Cataloid SI-40 (SiO ₂ solid content 40% by mass), Cataloid SI-50 (SiO ₂ solid content 47% by mass), Cataloid S I-350 (SiO ₂ solid content 30% by mass), Cataloid SI-500 (SiO ₂ solid content 20% by mass), Cataloid SI-45P (SiO ₂ solid content 40% by mass), Cataloid SI-80P (SiO ₂ solid content) 40% by mass), Cataloid SA (SiO ₂ solid content 30% by mass), Cataloid SC-30 (SiO ₂ solid content 30% by mass) (the above is made by Catalyst Chemical Industry Co., Ltd.), Silica Dole-20 (SiO ₂ solid content) min 20 wt%), silica Doll -30 (SiO ₂ solid content 30 wt%), silica Doll -40 (SiO ₂ solid content: 40 wt%), silica Doll -30S (SiO ₂ solid content 30 wt%), silica Doll -20AL (SiO ₂ solid content of 20 wt%), silica Doll -20A (SiO ₂ solid content of 20 wt%), silica Doll 20B (SiO ₂ solid content of 20 mass%), Shirikado -20G (SiO ₂ solid content of 20 wt%), silica Doll -20GA (SiO ₂ solid content of 20 wt%), ammonium silicate (SiO ₂ solid content: 40 wt%) (all manufactured by the Nippon Chemical Industrial Co., Ltd.) and the like Can be mentioned.

Examples of the cationic colloidal silica include Snowtex AK (manufactured by Nissan Chemical Industries, Ltd., SiO ₂ solid content 19% by mass), silica dol-20P (manufactured by Nippon Chemical Industry Co., Ltd., SiO ₂ solids content 20% by mass), and the like. Is mentioned.
These colloidal silica may be used individually by 1 type, and may be used in combination of 2 or more type.

(Surfactant)
The aqueous coating composition preferably contains an anionic surfactant and a nonionic surfactant from the viewpoint of stain resistance of the coating film. By using these specific surfactants, the outermost silica particle layer of the coating film can be thickened, and a coating film having remarkable hydrophilicity and antistatic properties can be obtained efficiently and effectively. .
The anionic surfactant and the nonionic surfactant may be added during the production process of the copolymer, or may be added when the aqueous coating composition is prepared after the production of the copolymer.

  Examples of the anionic surfactant include polyoxyalkylene aryl ether sulfate ester salt, polyoxyalkylene alkyl aryl ether sulfate ester salt, polyoxyalkylene aryl ether sulfate ester salt formalin condensate, polyoxyalkylene alkyl aryl ether A formalin condensate of a sulfate ester salt may be mentioned.

  0.1-10 mass parts is preferable with respect to 100 mass parts of copolymers, and, as for the quantity of an anionic surfactant, 0.5-8 mass parts is more preferable. By setting the amount of the anionic surfactant to 0.1 parts by mass or more, the stain resistance of the coating film, the stability during preparation of the aqueous coating composition, and the storage stability of the aqueous coating composition are improved. When emulsion polymerization is performed in the presence of an activator, the stability during polymerization is also improved. By adjusting the amount of the anionic surfactant to 10 parts by mass or less, the stain resistance of the coating film, the stability during preparation of the aqueous coating composition, the stability of the aqueous coating composition, without impairing the water resistance of the coating film, Storage stability is improved. When emulsion polymerization is performed in the presence of a surfactant, the stability during polymerization is also improved.

The polyoxyalkylene part of the anionic surfactant is used to increase the thickness of the outermost silica particle layer of the coating film, and to efficiently and effectively obtain a coating film having remarkable hydrophilicity and antistatic properties. Ethylene is preferable, and the number of repeating units is preferably 30 or less, and more preferably 20 or less.
Examples of the aryl part of the anionic surfactant include naphthyl, biphenyl, cumylphenyl, styrylphenyl, (mono-penta) benzylphenyl, (mono-penta) styrylphenyl, (mono-penta) styrylcyclohexylphenyl, (mono- Penta) benzylbiphenyl, styrylcumylphenyl and the like.
Examples of the sulfate salt of the anionic surfactant include sulfate ester sodium salt, sulfate ester potassium salt, sulfate ester calcium salt, sulfate ester ammonium salt and the like.

Examples of nonionic surfactants include polyoxyalkylene alkyl ethers.
The amount of the nonionic surfactant is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 9 parts by mass, and further preferably 1 to 8 parts by mass with respect to 100 parts by mass of the copolymer. By setting the amount of the nonionic surfactant to 0.1 parts by mass or more, the stain resistance of the coating film, the stability during preparation of the aqueous coating composition, and the storage stability of the aqueous coating composition are improved. When emulsion polymerization is performed in the presence of an activator, the stability during polymerization is also improved. By setting the amount of the nonionic surfactant to 10 parts by mass or less, the contamination resistance of the coating film, the stability during preparation of the aqueous coating composition, the stability of the aqueous coating composition can be reduced without impairing the water resistance of the coating film. Storage stability is improved. When emulsion polymerization is performed in the presence of a surfactant, the stability during polymerization is also improved.

The polyoxyalkylene part of the nonionic surfactant is used to increase the thickness of the outermost silica particle layer of the coating film, and to efficiently and effectively obtain a coating film having remarkable hydrophilicity and antistatic properties. Ethylene is preferred, and the repeating unit is preferably 10 or more, more preferably 20 or more. This effect becomes higher as the number of repeating units of polyoxyethylene is larger.
Examples of the alkyl part of the nonionic surfactant include linear or branched alkyl groups having 4 to 18 carbon atoms, naphthyl, biphenyl, cumylphenyl, styrylphenyl, (mono-penta) benzylphenyl, (mono-penta). ) Styrylphenyl, (mono-penta) styrylcyclohexylphenyl, (mono-penta) benzylbiphenyl, styrylcumylphenyl and the like.

  In order to improve the stability during preparation of the aqueous coating composition, the storage stability of the aqueous coating composition, and the polymerization stability when emulsion polymerization is performed in the presence of a surfactant, the anionic surfactants described above and Combined with known anionic, cationic, nonionic surfactants, polymeric emulsifiers, surfactants such as reactive emulsifiers with radically polymerizable unsaturated bonds in surfactant components, excluding nonionic surfactants May be. However, in order to thicken the outermost silica particle layer of the coating film and to obtain a coating film having remarkable hydrophilicity and antistatic properties efficiently and effectively, the above-mentioned anionic surfactant and nonionic surfactant are used. It is preferable to use an agent.

(Other ingredients)
For water-based paint compositions, pigments, antifoaming agents, pigment dispersants, leveling agents, anti-sagging agents, matting agents, UV absorbers, antioxidants, and heat resistance are used to achieve high performance as coating materials. Various additives such as improvers, slip agents, preservatives, plasticizers, film-forming aids; and other emulsion resins, water-soluble resins, viscosity control agents, and curing agents such as melamines may be added.

Examples of the film-forming aid include those used in ordinary water-based paints, such as linear, branched or cyclic aliphatic alcohols having 5 to 10 carbon atoms; alcohols containing aromatic groups General formula HO— (CH ₂ CHXO) _n —R ³ (R ³ represents a linear or branched alkyl group having 1 to 10 carbon atoms, X represents hydrogen or a methyl group, and n represents 1 to 1) Monoethers such as (poly) ethylene glycol or (poly) propylene glycol represented by general formula R ⁴ COO— (CH ₂ CHXO) _n —R ⁵ (R ⁴ and R ⁵ are carbon atoms) (Poly) ethylene glycol ether ester represented by (Poly) ethylene glycol ether ester represented by the formula (1) represents a linear or branched alkyl group of 1 to 10, X represents hydrogen or methyl group, and n represents an integer of 1 to 5. ) Propylene glycol ester Ether esters; aromatic organic solvents such as toluene and xylene; mono- or diisobutyrate of 2,2,4-trimethyl-1,3-pentanediol, 3-methoxybutanol, 3-methoxybutanol acetate, 3-methyl- Examples include 3-methoxybutanol and 3-methyl-3-methoxybutanol acetate.

(Painting method)
Examples of methods for applying the aqueous coating composition to the surface of various substrates include various coating methods such as spray coating, roller coating, bar coating, air knife coating, brush coating, and dipping.
A coating film is obtained by drying the water-based coating composition applied to the substrate surface at normal temperature or by heating to 40 to 200 ° C. Also, after drying at a low temperature of about room temperature to about 50 ° C. to form a coating film, the coating film is heated to a temperature higher than the glass transition temperature of the copolymer to strengthen the binding between the copolymer particles. A coating film with higher weather resistance can also be obtained.

(Base material)
Examples of the base material include cement mortar, slate board, gypsum board, extruded board, foamable concrete, metal, glass, porcelain tile, asphalt, wood, waterproof rubber material, plastic, and calcium silicate base material. The coating film of the present invention can be positioned as a surface finishing material for these various substrates.

<Painted object>
The coated article of the present invention has the coating film of the present invention.
Examples of the coated object of the present invention include building materials, building exteriors, building interiors, window frames, window glass, structural members, plate materials, vehicle exteriors, exteriors of machinery and articles, dustproof covers, reflectors for road signs, and line of sight Guide signs, road markings, various display devices, advertising towers, sound insulation walls for roads, sound insulation walls for railways, road decorative panels, light source covers for traffic lights, outdoor display boards, bridges, guardrails, tunnel interiors, lighting devices in tunnels, glass, Solar battery cover, solar water heater heat collection cover, plastic house, vehicle lighting cover, road mirror, vehicle mirror, motorcycle weighing cover and weighing panel, glass lens, plastic lens, helmet shield, goggles, house, Window glass for automobiles and railway vehicles, vehicle windshields, showcases, heat insulation showcases, membrane structural materials, heat exchange fins, glass surfaces at various locations, Lined, tire wheel, roofing material, roofing roof, antenna, transmission line, housing equipment, toilet bowl, bathtub, wash basin, lighting fixture, lighting cover, kitchenware, tableware, tableware container, dishwasher, dish dryer, sink , Cooking range, kitchen hood, ventilation fan, aquarium material for viewing, surface material in contact with circulating water in facilities using circulating water, anti-thrombogenic material, anti-protein adhesion material, anti-lipid adhesion material, contact lens, urination Catheters, transcutaneous devices, artificial organs, blood bags, blood collection bags, lung drainage, ship bottoms, tent canvas, slides, functional fibers, TVs, displays such as TVs, PCs, films to be affixed to these items, etc. Can be mentioned.

In the coating film of the present invention described above, since the silica particle layer having a certain thickness or more and spreading on the surface of the coating film is formed on the outermost layer of the coating film, the coating film has remarkable hydrophilicity. It is given and comes to show the self-cleaning effect by rainwater. Furthermore, since the silica particles come into contact with each other on the surface of the coating film, the coating film surface has conductivity, and adhesion of dirt due to static electricity is suppressed. As a result, the coating film of the present invention exhibits excellent stain resistance.
The above-mentioned coating film structure and coating film performance improve the dispersion stability of the copolymer and silica particles, and make it easier for the silica particles to float on the coating film surface during the film formation process. It becomes easy to obtain by controlling. Specifically, the absolute value of the zeta potential of the copolymer is 15 mV or more and 95 mV or less, and the absolute value of the zeta potential of the silica particles is 10 mV or more and 55 mV or less, thereby preventing aggregation during the mixing or film formation process, It tends to float on the surface of the coating film during film formation.
As the zeta potential measuring device, DT-1200 manufactured by Dispersion Technology can be used.
In addition, since only the coating film of the present invention exhibits sufficient stain resistance, it is not always necessary to have a multi-layer structure composed of a conventional overcoating, intermediate coating, and undercoating.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by this Example.
Evaluation of the coating film and the like were performed according to the following method.

(Preparation of a coating film for measuring the thickness of the silica particle layer and a test plate for evaluating antistatic properties)
An aqueous coating composition was applied to a PET film at 40 ° C. in an atmosphere of 40 ° C. with a bar coater # 60 and dried at 130 ° C. for 5 minutes. Then, what was dried at room temperature for 1 day was used as a coating film for measuring the thickness of the silica particle layer and a test plate for evaluating antistatic properties.

(Preparation of test plates for transparency evaluation)
An aqueous coating composition was applied to a glass plate with a 4 MIL applicator in an atmosphere of 40 ° C. and dried at 130 ° C. for 5 minutes to obtain a test plate for evaluation.

(Production of test plates for evaluation of water contact angle, carbon contamination resistance and weather resistance)
A water-based coating composition was applied to a zinc phosphate-treated steel plate (bonderite # 100-treated steel plate, plate thickness 0.8 mm, length 150 mm × width 70 mm) with a bar coater # 60 in an atmosphere of 40 ° C., and 130 ° C. For 5 minutes. Then, what was dried at room temperature for 1 day was used as a test plate for evaluation of water contact angle, carbon contamination resistance and weather resistance.

(Preparation of test panels for evaluation of outdoor exposure contamination resistance)
White using a zinc phosphate-treated steel plate (Bondelite # 100-treated steel plate, 0.8 mm thick, 300 mm long x 100 mm wide) with a trade name of Dianal LX-2011 (Mitsubishi Rayon Co., Ltd.) as an intermediate coating. An enamel paint (PWC (pigment content ratio) = 40 mass%) was spray-coated at room temperature so that the dry film thickness was 50 μm, and dried at 130 ° C. for 5 minutes. Next, the water-based paint composition was spray-coated at room temperature so that the dry film thickness was 30 μm, dried at 130 ° C. for 5 minutes, and then dried at room temperature for 1 day. A board was used.

(Preparation of test plates for evaluation of frost resistance)
Gypsum slag perlite plate (thickness 12 mm) is coated with a white enamel paint (PWC = 40% by mass) using a trade name of Dianal LX-1010 (Mitsubishi Rayon Co., Ltd.) as a sealer with a coating amount of 90 to 100 g / m ^2. (Wet mass) was spray-coated at room temperature and dried at 130 ° C. for 5 minutes, followed by white enamel paint using a trade name of Dianal LX-2011 (manufactured by Mitsubishi Rayon Co., Ltd.) as an intermediate coating ( PWC = 40 mass%) was spray-coated at room temperature so that the coating amount was 90 to 100 g / m ² (wet mass) and dried for 5 minutes at 130 ° C. Then, the aqueous coating composition was coated. There were spray coated at room temperature so as to 50~60g / m ² (wet weight), and dried for 5 minutes at 130 ° C., a material obtained by drying at room temperature for 1 day, for evaluation of the frost resistance test And the.

(Thickness of silica particle layer)
Using a transmission electron microscope (H-7600, manufactured by Hitachi, Ltd.), a cross section of the coating film was photographed under the condition of an acceleration voltage of 80 kV, and the thickness (nm) of the silica particle layer was obtained from the obtained TEM observation image according to the method described above. ) In the table, “-” indicates that the silica particle layer was not formed.

(transparency)
The transparency of the coating film on the test plate for evaluation was visually observed and judged according to the following criteria.
“O”: Transparent.
“△”: Translucent.
“×”: cloudiness.

(Water contact angle)
Using a CA-X150 type FACE contact angle meter manufactured by Kyowa Interface Science Co., Ltd., 0.4 μL of water drops (3 scales on the screen) are dropped on the coating film of the evaluation test plate, and water contact after 30 seconds has passed. The corner was measured.

(Antistatic)
The test plate for evaluation was attached to STATIC HONES TMETER S-5109 manufactured by Sicid Electrostatic Co., Ltd., half-life measurement shown in JIS L 1094 was performed, and the determination was made according to the following criteria. At this time, after applying plus 10 kV for 30 seconds, the application was stopped, and measurement was performed for 180 seconds from the start of application while rotating the turntable.
“◎”: less than 30 seconds.
“◯”: 30 seconds or more and less than 90 seconds.
“Δ”: 90 seconds or more and less than 180 seconds.
“×”: 180 seconds or more.
(Carbon decontamination)
Immediately after spraying water onto the coating film of the test plate for evaluation, a 10% by mass petroleum benzine solution of carbon MA100 (manufactured by Mitsubishi Chemical Corporation) was dropped using a dropper, and rinsed with tap water after 5 seconds. It was. About the part which dipped carbon solution, the adhesion degree to the coating film of carbon was observed visually, and the following references | standards determined.
“◎”: No adhesion.
“◯”: Slightly adhered partially.
“△”: Thinly adhered to the entire surface.
"X": It adheres to the whole surface deeply.

(Outdoor exposure contamination resistance)
Fold the test plate for evaluation at a third of the length from the top so that the inner angle is 135 degrees, and let the test plate face the south side in the Mitsubishi Rayon Co., Ltd. Toyohashi Office (Ushikawa-dori, Toyohashi City) Installed so that the surface with a large area (vertical surface) is vertical and the surface with a smaller area (upper surface) on top, and after exposure for 6 months from May to October 2004, paint on the upper surface The difference ΔL in whiteness before and after exposure of the film was measured with a color difference meter, and the presence or absence of rain streak on the vertical surface was visually evaluated. Judgment criteria are shown below.
(Difference in whiteness before and after exposure on the upper surface ΔL)
“◎”: less than 2.5.
“◯”: 2.5 or more and less than 5.0.
“Δ”: 5.0 or more and less than 7.5.
"X": 7.5 or more.
(Presence or absence of rain stripes on the vertical surface)
“◎”: No rain stripe contamination.
“O”: Slightly contaminated rain stripes.
“×”: Rain line contamination is clearly observed.

(Weatherability)
A test plate having a size of 70 mm × 50 mm is cut out from the test plate for evaluation, and this test plate is put into a die plastic metal weatherer KU-R4-W type (manufactured by Daipura Wintes Co., Ltd.). Test cycle: irradiation 4 hours (Spray 5 seconds / 15 minutes) / condensation 4 hours, UV intensity: 85 mW / cm ² , black panel temperature: 63 ° C. during irradiation / 30 ° C. during condensation, humidity: 50% RH during irradiation / 96% RH during condensation The weather resistance test was conducted. Using the 60 ° gloss retention of the coating after 600 hours as an indicator of weather resistance, the following criteria were used.
“◎”: 80% or more.
“◯”: 70% or more and less than 80%.
“Δ”: 60% or more and less than 70%.
"X": Less than 60%.

(Frost damage resistance)
It was measured by the ASTM-C666A method (200 cycles) and judged according to the following criteria.
“◎”: No crack or gloss change.
“◯”: No crack, but slightly glossy.
“△”: Minor cracks occurred.
“×”: Remarkable cracking occurred.

[Production Example 1]
Preparation of aqueous dispersion of polyorganosiloxane:
95 parts by mass of cyclic dimethylsiloxane oligomer 3 to 7-mer mixture, 5 parts by mass of γ-methacryloyloxypropyltrimethoxysilane, 250 parts by mass of deionized water, 0.4 part by mass of sodium dodecylbenzenesulfonate and 0 part of dodecylbenzenesulfonic acid A composition consisting of .4 parts by mass was premixed with a homomixer and forcibly emulsified with a pressure homogenizer at a pressure of 200 kg / cm ² to obtain a raw material pre-emulsion.
Next, 55 parts by mass of water and 5 parts by mass of dodecylbenzenesulfonic acid were charged into a flask equipped with a stirrer, a reflux condenser, a temperature controller and a dropping pump, and the internal temperature of the flask was maintained at 85 ° C. with stirring. The raw material pre-emulsion was added dropwise over 4 hours. After completion of the dropwise addition, the polymerization was further allowed to proceed for 1 hour, cooled, and dodecylbenzenesulfonic acid and an equimolar amount of ammonia were added to prepare a polyorganosiloxane aqueous dispersion (SiEm). The solid content was 22.7% by mass.

[Example 1]
In a flask equipped with a stirrer, reflux condenser, temperature controller and dropping pump, 58 parts by mass of deionized water, CP-12Na (trade name, manufactured by Toho Chemical Co., Ltd., anionic surfactant) 1.7 parts by mass (Solid content 0.5 parts by mass), SiEm: 22 parts by mass (solid content 5 parts by mass), a mixture of radical polymerizable monomers shown in “First stage (inner layer)” in Table 1, and perbutyl H69 (Japan) 0.09 parts by mass of a fat and oil Co., Ltd. radical polymerization initiator) was charged. After raising the internal temperature of the flask to 55 ° C, ferrous sulfate 0.0002 parts by mass / ethylenediaminetetraacetic acid disodium (EDTA) 0.0005 parts by mass / Longalite 0.05 parts by mass / deionized water 1 part by mass A reducing agent aqueous solution was added. After confirming the peak top temperature due to polymerization exotherm, the internal temperature of the flask was maintained at 65 ° C., and 1 hour after the addition of the reducing agent aqueous solution, Emulgen 1150S-70 (trade name, manufactured by Kao Corporation, nonionic surfactant) ) 1.43 parts by mass (solid content 1 part by mass) / deionized water 1.9 parts by mass aqueous surfactant solution was added.

  0.5 hours after addition of the aqueous surfactant solution, a mixture of radical polymerizable monomers shown in “Second stage (outer layer)” in Table 1, 21 parts by mass of deionized water, 6.7 parts by mass of CP-12Na (2 mass parts of solid content) and AMP-90 (trade name, manufactured by Dow Chemical Japan Co., Ltd., basic compound) 0.23 part of a pre-emulsion liquid and VA-061 (trade name, Wako, radical polymerization initiator) 0.1 parts by mass / methanol 2 parts by mass / deionized water 3 parts by mass were added dropwise over 2 hours in two series. During the dropping, the internal temperature of the flask was maintained at 65 ° C., and after the dropping was completed, the temperature was maintained at 65 ° C. for 1 hour. After adding 0.56 mass part of 28 mass% ammonia water, it hold | maintained at 65 degreeC for 0.5 hour further. Then, it cooled to room temperature and obtained the aqueous dispersion liquid of the copolymer. The unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer in the copolymer (solid content: 100% by mass) was 5.25% by mass.

1.43 parts by mass (1 part by mass of solid content) of Emulgen 1150S-70 was added to the aqueous dispersion of the copolymer, and Snowtex O (trade name, manufactured by Nissan Chemical Industries, Ltd., colloidal silica, silica particles) 25 parts by mass (solid content 5 parts by mass) and 17 parts by mass of butyl cellosolve as a film-forming aid were added to obtain an aqueous coating composition. The amount of silica particles (solid content) relative to 100 parts by mass of the copolymer (solid content) was 5 parts by mass.
A coating film is formed using the obtained water-based coating composition, the measurement of the thickness of the silica particle layer, transparency, water contact angle, antistatic, carbon contamination resistance, outdoor exposure contamination resistance, weather resistance, The frost damage resistance was evaluated. The results are shown in Table 3. Moreover, the TEM observation image of a coating-film cross section is shown in FIG.

[Example 2]
An aqueous copolymer dispersion was obtained in the same manner as in Example 1 except that the amount of the nonionic surfactant was changed to the amount shown in Table 1. The unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer in the copolymer (solid content: 100% by mass) was 5.25% by mass.
Moreover, the aqueous coating material composition was obtained like Example 1 except having changed the amount of emulsifiers added to 0 mass part. The amount of silica particles (solid content) relative to 100 parts by mass of the copolymer (solid content) was 5 parts by mass.
A coating film is formed using the obtained water-based coating composition, the measurement of the thickness of the silica particle layer, transparency, water contact angle, antistatic, carbon contamination resistance, outdoor exposure contamination resistance, weather resistance, The frost damage resistance was evaluated. The results are shown in Table 3.

Example 3
An aqueous copolymer dispersion was obtained in the same manner as in Example 1 except that the amount of the nonionic surfactant was changed to the amount shown in Table 1. The unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer in the copolymer (solid content: 100% by mass) was 5.25% by mass.
Moreover, except having changed the quantity of colloidal silica into the quantity shown in Table 1, it carried out similarly to Example 2, and obtained the aqueous coating material composition. The amount of silica particles (solid content) relative to 100 parts by mass of the copolymer (solid content) was 1 part by mass.
A coating film is formed using the obtained water-based coating composition, the measurement of the thickness of the silica particle layer, transparency, water contact angle, antistatic, carbon contamination resistance, outdoor exposure contamination resistance, weather resistance, The frost damage resistance was evaluated. The results are shown in Table 3.

Example 4
In a flask equipped with a stirrer, a reflux condenser, a temperature controller, and a dropping pump, 80 parts by mass of deionized water, 2.5 parts by mass of CP-12Na (trade name, manufactured by Toho Chemical Co., Ltd., anionic surfactant) A mixture of radical polymerizable monomers shown in (solid content of 0.75 part by mass) and “first stage (inner layer)” in Table 1 was charged. After raising the internal temperature of the flask to 50 ° C., an initiator aqueous solution of 0.15 part by weight of ammonium persulfate / 1 part by weight of deionized water was added, and 0.05 part by weight of sodium bisulfite / 1 part by weight of deionized water. Part of the reducing agent aqueous solution was added. After confirming the peak top temperature due to the polymerization exotherm, the internal temperature of the flask was maintained at 65 ° C., and 1 hour after the addition of the reducing agent aqueous solution, Emulgen 1150S-70 (trade name, manufactured by Kao Corporation, nonionic surfactant) A surfactant aqueous solution of 1.43 parts by mass (solid content 1 part by mass) /1.9 parts by mass of deionized water was added.

  0.5 hours after addition of the aqueous surfactant solution, a mixture of radical polymerizable monomers shown in “Second stage (outer layer)” in Table 1, 21 parts by mass of deionized water, 6.67 parts by mass of CP-12Na, and AMP-90: 0.115 parts of pre-emulsion liquid preliminarily dispersed and VA-061: 0.1 parts by weight / methanol 2 parts by weight / deionized water 3 parts by weight of initiator solution Two series were dripped over time. During the dropping, the internal temperature of the flask was maintained at 65 ° C., and after the dropping was completed, the temperature was maintained at 65 ° C. for 1 hour. After adding 0.98 parts by mass of AMP-90, the mixture was further maintained at 65 ° C. for 0.5 hour. Then, it cooled to room temperature and obtained the aqueous dispersion liquid of the copolymer. The unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer in the copolymer (solid content: 100% by mass) was 2.05% by mass.

1.43 parts by mass (1 part by mass of solid content) of Emulgen 1150S-70 was added to the aqueous dispersion of the copolymer, and Snowtex O (trade name, manufactured by Nissan Chemical Industries, Ltd., colloidal silica, silica particles) 25 parts by mass (solid content 5 parts by mass) and 5 parts by mass of butyl cellosolve as a film-forming aid were added to obtain an aqueous coating composition. The amount of silica particles (solid content) relative to 100 parts by mass of the copolymer (solid content) was 5 parts by mass.
A coating film is formed using the obtained water-based coating composition, the measurement of the thickness of the silica particle layer, transparency, water contact angle, antistatic, carbon contamination resistance, outdoor exposure contamination resistance, weather resistance, The frost damage resistance was evaluated. The results are shown in Table 3.

[Comparative Example 1]
An aqueous copolymer dispersion was obtained in the same manner as in Example 4 except that the polyorganosiloxane was changed to 0 part by mass and the type and amount of the radical polymerizable monomer were changed as shown in Table 2. The unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer in the copolymer (solid content: 100% by mass) was 0% by mass.
Further, an aqueous coating composition was obtained in the same manner as in Example 3. The amount of silica particles (solid content) relative to the copolymer (solid content 100 mass%) was 5 parts by mass.
A coating film is formed using the obtained water-based coating composition, the measurement of the thickness of the silica particle layer, transparency, water contact angle, antistatic, carbon contamination resistance, outdoor exposure contamination resistance, weather resistance, The frost damage resistance was evaluated. The results are shown in Table 3.

[Comparative Example 2]
An aqueous copolymer dispersion was obtained in the same manner as in Example 3 except that the type and amount of the radical polymerizable monomer were changed as shown in Table 2. The unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer in the copolymer (solid content: 100% by mass) was 5.25% by mass.
Further, an aqueous coating composition was obtained in the same manner as in Example 3 except that the amount of colloidal silica was changed to the amount shown in Table 2. The amount of silica particles (solid content) relative to the copolymer (solid content 100% by mass) was 0.2 parts by mass.
A coating film is formed using the obtained water-based coating composition, the measurement of the thickness of the silica particle layer, transparency, water contact angle, antistatic, carbon contamination resistance, outdoor exposure contamination resistance, weather resistance, The frost damage resistance was evaluated. The results are shown in Table 3.

[Comparative Example 3]
An aqueous dispersion of a copolymer was obtained in the same manner as in Example 4 except that the type and amount of the radical polymerizable monomer were changed as shown in Table 2. The unit derived from the hydrolyzable silyl group-containing radical polymerizable monomer in the copolymer (solid content: 100% by mass) was 2.05% by mass.
An aqueous coating composition was obtained in the same manner as in Example 4 except that the type and amount of colloidal silica were changed as shown in Table 2. The amount of silica particles (solid content) relative to 100 parts by mass of the copolymer (solid content) was 5 parts by mass.
A coating film is formed using the obtained water-based coating composition, the measurement of the thickness of the silica particle layer, transparency, water contact angle, antistatic, carbon contamination resistance, outdoor exposure contamination resistance, weather resistance, The frost damage resistance was evaluated. The results are shown in Table 3.

The abbreviations in Tables 1 and 2 indicate the following compounds.
“MMA”: methyl methacrylate,
“2-HEMA”: 2-hydroxyethyl methacrylate,
“EDMA”: ethylene dimethacrylate,
“N-BA”: n-butyl acrylate,
“SZ-6030”: γ-methacryloyloxypropyltrimethoxysilane (manufactured by Dow Corning Toray Silicone Co., Ltd.),
“MAA”: methacrylic acid,
“N-BMA”: n-butyl methacrylate,
“2-EHA”: 2-ethylhexyl acrylate,
“ZM-84”: unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone (ε-caprolactone modified 2-hydroxyethyl methacrylate),
Snowtex O: (trade name, manufactured by Nissan Chemical Industries, colloidal silica, average particle diameter of silica particles 15 nm),
Snowtex ZL: (trade name, manufactured by Nissan Chemical Industries, colloidal silica, average particle diameter of silica particles of 85 nm),
CP-12Na (trade name, manufactured by Toho Chemical Co., Ltd.)
Emulgen 1150S-70 (trade name, manufactured by Kao Corporation).

  As is clear from Table 3, the coating films of the examples have excellent water contact angle and antistatic properties, so that they have excellent contamination resistance (carbon contamination removal resistance and outdoor exposure contamination resistance), transparency, and weather resistance. It also had frost resistance. On the other hand, it was difficult for the coating film of the comparative example to exhibit the stain resistance, transparency, weather resistance, and frost damage resistance in a balanced manner. In particular, in the coating film of the comparative example, the thickness of the outermost silica particle layer of the coating film was small, and the contamination resistance was low.

  By increasing the thickness of the outermost silica particle layer of the coating film, the coating film of the present invention has excellent stain resistance and transparency, weather resistance, water resistance, and frost damage resistance. Such a coating film can be used for various coating purposes for the purpose of protecting the housing of buildings, civil engineering structures, and the like, and is extremely useful industrially.

It is a TEM observation image which shows an example of the cross section of the coating film of this invention. It is a schematic diagram which shows an example of the cross section of the coating film of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Coating film 11 Copolymer 12 Silica particle 13 Silica particle layer

Claims (2)

A coating film containing a copolymer and silica particles,
The thickness of the layer which consists of a silica particle formed in the outermost layer of this coating film is 30 nm or more, The coating film characterized by the above-mentioned. A coated article having the coating film according to claim 1.

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