JP3327207B2 - Article having hydrophilic coating film and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an article having a hydrophilic coating having on its surface a layer whose surface is hydrophilized by photocatalysis, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years,
From the viewpoints of environmental pollution and ensuring a safe working environment, in the field of paints and coatings, it is required to change the dispersion medium from an organic solvent to an aqueous solvent.

Based on this requirement, emulsion paints obtained by emulsion polymerization of radically polymerizable vinyl monomers represented by acrylic resin have been widely used as basic materials for coating agents because of their excellent film-forming properties and chemical resistance. Have been. However, this type of coating agent has the disadvantage of essentially lacking water resistance and weather resistance.

On the other hand, a silicone resin (resin) obtained by hydrolyzing and condensing a silane compound has a high hardness and the ability to form a film having excellent weather resistance, water resistance, heat resistance and water repellency. , Has attracted attention as a coating agent. On the other hand, there are drawbacks in that the film formability, alkali resistance, film flexibility are poor, and the storage stability is poor due to the silanol group having a high condensation activity. In addition, since silicone resins are generally used in the form dissolved in organic solvents, there are problems such as the danger of fire and explosion, toxicity to the human body, and environmental pollution. I have.

[0005] Against this background, emulsion compositions that form a composite film of an acrylic resin and a silicone compound have recently attracted attention, and several reports have been made. However, currently reported silicone-acryl emulsion compositions are basically synthesized by a method in which a part of the acrylic resin is modified with a hydrolyzable silyl group or a method in which alkoxysilanes are added during acrylic emulsion polymerization. The silicone content at a practical level at which storage stability can be maintained is at most about 20% by weight based on the resin solid content.

On the other hand, recently, a technique for imparting antibacterial and antifouling properties to a coating film surface using a photocatalyst has been reported. This means that when a film containing a photocatalyst immobilized on the outermost layer is irradiated with sunlight containing ultraviolet rays, active radical species generated by the photocatalyst decompose bacteria and oil stains. It is expected to be applied to paints for structures. As a method for forming the photocatalyst-containing film, (1) a method in which the photocatalyst is directly applied to the substrate and then sintered at a high temperature; (2) a method in which an intermediate adhesive layer is provided between the substrate and the photocatalyst; There has been reported a method of applying a binder resin composition and forming a coating film with one coat. (1) can be applied only to heat-resistant inorganic base materials such as metal and glass,
In the case of (3), since the photocatalyst is buried inside the coating film, there is a problem that the content of the photocatalyst must be increased in order to sufficiently exert the photocatalytic ability. Most practical. However, since organic matter in contact with the photocatalyst is decomposed by radical species generated by light irradiation, a general-purpose organic resin containing acrylic resin, urethane resin, etc. as a main component in the intermediate adhesive (undercoat) layer that fixes the photocatalyst When a paint is used, a large amount of sunlight is irradiated by outdoor exposure, and oxidative decomposition of the organic resin occurs at the interface between the organic resin and the photocatalyst, so that the durability is extremely poor. In order to prevent this, it is also reported that it is preferable to use a silicone resin or a fluororesin paint for the undercoat layer.

In addition, a phenomenon has been reported in which, when a coating film containing a photocatalyst is irradiated with light, the contact angle of water on the surface is reduced to 10 degrees or less. This is considered to be because water is adsorbed on the hydroxyl groups on the surface of the photocatalyst particles. It is known that this hydrophilic coating film exhibits extremely high antifouling properties over a long period of time because pollutants are washed away by rainwater. This is thought to be manifested by a mechanism different from the above-mentioned antifouling property imparting by oxidative decomposition of the photocatalyst,
The hydrophilicity of the photocatalyst does not always correlate with the oxidative decomposition power due to the generation of radical species.

In forming such a hydrophilic coating film,
Which resin layer is used as the intermediate adhesive layer is a very important choice. When it is necessary to prioritize weather resistance, an inorganic coating containing silicone resin as the main component should be most suitable, but adhesion to organic resin base materials such as PET and polycarbonate resin is low without primer. In addition, there is a disadvantage that the film itself has poor flexibility and alkali resistance. On the other hand, an undercoat layer containing an organic resin such as an acrylic resin as a main component is particularly excellent in adhesion to an organic resin base material, and can be easily provided with low-temperature curability and flexibility. It is suitable for the undercoating of paint. Further, if a photocatalyst having a low oxidizing ability and a high hydrophilizing ability can be selected, it is considered that a photocatalyst-containing coating film having excellent weather resistance can be formed.

However, the mechanism of the expression of hydrophilicity by the photocatalyst has not been completely elucidated, and at present, it is impossible to select a type of photocatalyst having a low oxidizing ability and a high hydrophilizing ability. Therefore, development of an undercoat layer that minimizes weather deterioration due to a photocatalyst while maintaining adhesion and flexibility to an organic resin substrate is extremely important for practical use of a hydrophilic photocatalyst-containing coating film.

[0010]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, as a method of immobilizing a photocatalyst on the surface of a substrate, a silicone resin was used. By coating a silicone-acryl composite film containing at least 80% by weight of the silicone-acrylic composite film as an undercoat layer, and applying and fixing a coating solution containing a photocatalyst thereon.
When the photocatalyst is immobilized on the surface, a coating film with good adhesion can be formed without a primer on various substrates such as an organic resin, and is excellent in low-temperature curability, flexibility, weather resistance, and sunlight. The present inventors have found that the surface becomes hydrophilic by photocatalysis by irradiation, and a coating film exhibiting antifouling property, antibacterial property and antifogging property can be obtained, and the present invention has been accomplished. .

Hereinafter, the present invention will be described in more detail. The article having a hydrophilic coating film of the present invention comprises a first layer composed of a silicone-acrylic resin composite film containing 30 to 80% by weight of a silicone resin based on the total resin solid content on a substrate, and a photocatalyst thereon. A second layer composed of a containing layer is formed.

Here, the hydrophilic coating film is used to protect the surface of steel or stainless steel building materials, aluminum sash building materials, etc., coatings for automobiles and electric appliances, plastic plates, films for magnetic or thermal recording, Packaging film,
Surface protection coatings such as vinyl cloth, surface protection coatings for optical articles such as spectacle lenses, surface protection coatings for plywood, mortar, concrete, cement exterior wall materials or ceramic panels (ALC boards, sizing boards, gypsum boards), It can be used as a surface protective coating for bricks, glass porcelain, artificial marble and the like. The base material is selected according to the type of the article, and the material of the base material is plastic (organic resin), ceramic,
Although not particularly limited, such as glass, metal, or a composite thereof, an organic resin flat plate such as polycarbonate and acrylic resin, and an organic resin film such as PET resin can be preferably used.

In the present invention, a silicone-acrylic resin composite film is formed as a first layer on the substrate.

In this case, in the silicone-acrylic resin composite film, the content of the silicone resin with respect to the total resin solid content is 30 to 80% by weight, preferably 35 to 80% by weight.
It is 70% by weight, more preferably 40 to 60% by weight.
When the amount is less than 30% by weight, degradation is caused at the resin interface between the photocatalyst and the undercoat layer in an exposure test, and the appearance of the photocatalyst falls off, whitening of the film, etc. is remarkable, which is not suitable. On the other hand, 8
If the amount is more than 0% by weight, the adhesion to the substrate, alkali resistance, and flexibility are remarkably reduced, and the disadvantages of the inorganic coating composed of a silicone resin cannot be improved, resulting in poor practicality.

For forming the first layer of the present invention, the following method of applying a silicone-acrylic resin emulsion composition is most preferred. That is, (1) the following average composition formula (1): R ¹ _m R ² _n Si (OH) _p (X) _q O _{(4-mnpq) / 2} (1) (where R ¹ is an unsubstituted monovalent _carbon A hydrogen group, R ² is a substituted monovalent hydrocarbon group, X is a hydrolyzable group, and m, n, p, and q are 0.5 ≦ m ≦ 1.8, 0 ≦ n ≦ 1.0, 0 < p ≦ 1.5, 0 ≦ q ≦ 0.5, 0.5 ≦ m + n ≦ 1.8, 0 <p + q ≦ 1.5) Non-water-soluble silanol group-containing A silicone resin-containing emulsion composition containing 100 parts by weight of a silicone resin and (2) 25 to 233 parts by weight of a radically polymerizable vinyl monomer as a main component and substantially containing no organic solvent and containing an aqueous emulsion polymer.

Here, in the silanol group-containing silicone resin of the above formula (1), R ¹ represents an unsubstituted monovalent hydrocarbon group, preferably has 1 to 10 carbon atoms, and has a methyl group,
Ethyl group, propyl group, isopropyl group, butyl group, t
Alkyl groups such as butyl group, hexyl group, cyclohexyl group, octyl group, decyl group, vinyl group, allyl group, 5
Specific examples include alkenyl groups such as -hexenyl group and 9-decenyl group, and aryl groups such as phenyl group. Among these, a methyl group, a propyl group, a hexyl group, and a phenyl group are preferred. In particular, when weather resistance is required, a methyl group is preferable. When water repellency is required, a long-chain alkyl group is preferably used. When imparting flexibility to a film, a phenyl group is used. Is good.
In this case, in particular, the content of methyl groups in all organic substituents (R ¹ + R ² ) is at least 50 mol%, especially 80 mol%
It is preferable that it is above.

R ² represents a substituted monovalent hydrocarbon group.
The substituted monovalent hydrocarbon group is obtained by substituting a part or all of the hydrogen atoms of the above unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms with a substituent. Examples of the substituent include (i) fluorine, A halogen atom such as chlorine; (ii) an epoxy functional group such as a glycidyloxy group or an epoxycyclohexyl group;
i) (meth) acryl functional groups such as methacryl group and acrylic group, (iv) amino functional groups such as amino group, aminoethylamino group, phenylamino group, dibutylamino group, (v) mercapto group, tetrasulfide group, etc. (Vi) an alkyl ether functional group such as a (polyoxyalkylene) alkyl ether group;
i) Anionic groups such as a carboxyl group and a sulfonyl group, and (viii) a group containing a quaternary ammonium salt structure are applicable. Specific examples of the substituted monovalent hydrocarbon group include a trifluoropropyl group, a perfluorobutylethyl group, a perfluorooctylethyl group,
Chloropropyl group, 2- (chloromethylphenyl) ethyl group, 3-glycidyloxypropyl group, 2- (3,4-
Epoxycyclohexyl) ethyl group, 5,6-epoxyhexyl group, 9,10-epoxydecyl group, 3- (meth) acryloxypropyl group, (meth) acryloxymethyl group, 11- (meth) acryloxyundecyl group , 3
-Aminopropyl group, N- (2-aminoethyl) aminopropyl group, 3- (N-phenylamino) propyl group,
Examples include a 3-dibutylaminopropyl group, a 3-mercaptopropyl group, a 2- (4-mercaptomethylphenyl) ethyl group, a polyoxyethyleneoxypropyl group, a 3-hydroxycarbonylpropyl group, and a 3-tributylammoniumpropyl group. it can. In order to improve the adhesion to the substrate, it is preferable to apply an epoxy, amino, mercapto functional group or the like. In order to achieve a tight block with a vinyl polymer, it is preferable to use a (meth) acryl functional group capable of radical copolymerization or a mercapto functional group having a function as a chain transfer agent. When cross-linking is attempted with a bond other than the siloxane bond with the vinyl polymer, a functional group capable of reacting with an organic functional group contained in the vinyl polymer may be introduced. For example, an epoxy group (hydroxy group, amino group) Group, a carboxy group, etc.), an amino group (a reaction with an epoxy group, an acid anhydride group, etc.) and the like.

Specific examples of the hydrolyzable group X include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group,
Examples include an alkoxy group such as a butoxy group, a sec-butoxy group and a t-butoxy group, an alkenyloxy group such as an isopropenoxy group, an acetoxy group such as a phenoxy group, and an oxime group. It is preferable to use an alkoxy group, particularly a methoxy group, an ethoxy group, or an isopropoxy group, from the viewpoint of hydrolysis / condensation reactivity and stability in the emulsion.

M, n, p and q are each 0.5 ≦ m ≦ 1.
8, 0 ≦ n ≦ 1.0, 0 <p ≦ 1.5, 0 ≦ q ≦ 0.
5, a number that satisfies the ranges of 0.5 ≦ m + n ≦ 1.8 and 0 <p + q ≦ 1.5. In other words, the silicone resin forms a strong three-dimensional siloxane bond in the curing process, prevents the acrylic resin from being eluted and swelled by the organic solvent, and has sufficient cross-linking property to form a denser composite film. is necessary. When the composition ratio m of the unsubstituted monovalent hydrocarbon group R ¹ is less than 0.5, the crosslink density of the silicone resin is too high, and the crack resistance is poor. On the other hand, when it is larger than 1.8, the crosslinking density is low, the network of the silicone resin is insufficiently formed, and the acrylic resin easily melts out of the silicone resin network even when completely cured, which is not suitable. The substituted monovalent hydrocarbon group R ² is not an essential component, but an organic group capable of forming a chemical bond with a reactive substituent contained in the acrylic resin may be included on the silicone resin side. The silanol group, which is a condensation reactive group, must be contained. However, when the amount p of the silanol group exceeds 1.5, the storage stability is poor and it is not suitable. Although the hydrolyzable group X usually slightly remains after hydrolysis, in the silicone resin used in the present invention, the composition ratio q of X is preferably 0.5 or less. If it exceeds 0.5, hydrolysis proceeds during the emulsion polymerization and during storage after the polymerization, and by-products such as alcohol are generated, thereby destabilizing the emulsion.

In order to form a more dense and highly transparent composite film, it is important that the silicone resin to be composited with the acrylic resin has the following molecular structure.

That is, (a) 30 to 100 mol% of the structural unit (T unit) represented by the formula R ³ —SiZ ₃ , and of the T units, the formula R ³ —Si (OH) Z ′ 30 to 80 mol% of a structural unit (T-2 unit) containing one silanol group represented by ₂ (wherein R ³ represents a substituted or unsubstituted monovalent hydrocarbon group) , Z represents an OH group, a hydrolyzable group or a siloxane residue, and Z ′ represents a siloxane residue.) And a silanol group-containing silicone resin having a number average molecular weight of 500 or more is suitable.

The siloxane residue means a substituent bonded to an adjacent silicon atom via an oxygen atom to form a siloxane bond, and can be represented by -O-Si≡.

A silicone-acrylic resin composite emulsion composition obtained by emulsion polymerization of a mixed solution containing such a silicone resin and a radically polymerizable vinyl monomer described below does not change over time at room temperature for a long time. Furthermore, the coating film is excellent in transparency, acid resistance, alkali resistance,
It is possible to form a coating film having excellent organic solvent resistance and weather resistance.

Equation R^Three-SiZ_ThreeThe T unit represented by
Structure that greatly affects the degree of crosslinking and curability of corn resin
It is contained in a unit of 30 to 100 mol%. 30 content
If it is less than mol%, the formed film has low hardness, and
Curability may also be poor. Vinyl in emulsion particles
Active silanol entangled uniformly with the polymer
In order to control the degree of freedom of the
It is necessary to give structure. T unit content is 50-1
If the range of 00 mol% is satisfied, the silicone resin
It is more preferable because it is rigid and has good storage stability.
No.

In this case, the other structural unit is R
^Three _ThreeSiZ 0 to 10 mol% of an M unit represented by the formula:^Three _TwoSiZ
_Two0 to 50 mol% of a D unit represented by_FourRepresented by
0 to 30 mol% of the Q unit may be used in combination. Cured film
In order to further increase the hardness of
Conversely, for the purpose of imparting flexibility to the cured film,
It is preferable to use D units in combination.

As described above, 30 to 80 mol of T-2 units containing only one silanol group represented by R ³ —Si (OH) Z ′ ₂ in the T units of R ³ —SiZ _3. %, But in this case, as described above, since the siloxane residue represented by Z ′ can be represented by —O—Si≡, the T-2 unit is represented by R ³ —Si ( O
H) (—O—Si≡) ₂ .

Here, as the substituted or unsubstituted monovalent hydrocarbon group for R ³ , the same groups as those described above for R ¹ and R ² can be mentioned, but the organic substituent R ³ in the silicone resin can be exemplified.
Is 50 mol% in order to further improve the weather resistance of the coating film.
The above is preferably a methyl group.

The number average molecular weight of the silicone resin is preferably 500 or more, more preferably 80 or more.
0 to 3000, and 800 to 100 in weight average molecular weight.
About 00 is suitable.

The silicone resin may be manufactured by any method as long as the above conditions are satisfied. A specific manufacturing method will be described below. As a raw material for the production, one hydrolyzable group such as the above-described hydrolyzable group or chlorine is used.
Any silane compound containing 3, 4 or 4 organic substituents satisfying the above conditions can be used. Examples of such a silane compound include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldichlorosilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, 5-hexenyltrimethoxysilane, and 3-glycide. Xypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3 -(Meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, 4-vinylphenyltrimethoxysilane 3- (4-vinylphenyl) propyltrimethoxysilane, 4-vinylphenyl methyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyl methyl dimethoxy silane, 3-
Aminopropylmethyldiethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3-
In addition to so-called silane coupling agents such as mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane, tetrachlorosilane, tetramethoxysilane, Ethoxysilane, tetrabutoxysilane, methyltrichlorosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltributoxysilane, methyltriisopropenoxysilane, dimethyldichlorosilane, dimethyldimethoxysilane, dimethyldi Ethoxysilane, dimethyldiisopropoxysilane, dimethyldibutoxysilane,
Dimethyldiisopropenoxysilane, trimethylchlorosilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropenoxysilane, ethyltrichlorosilane, ethyltrimethoxysilane, propyltrichlorosilane, butyltrichlorosilane, butyltrimethoxysilane, hexyltrichlorosilane , Hexyltrimethoxysilane, decyltrichlorosilane, decyltrimethoxysilane, phenyltrichlorosilane,
Phenyltrimethoxysilane, cyclohexyltrichlorosilane, cyclohexyltrimethoxysilane, propylmethyldichlorosilane, propylmethyldimethoxysilane, hexylmethyldichlorosilane, hexylmethyldimethoxysilane, phenylmethyldichlorosilane, phenylmethyldimethoxysilane, diphenyldichloro Examples of usable silane compounds include silane, diphenyldimethoxysilane, dimethylphenylchlorosilane, and partial hydrolysates thereof. In addition, when the hydrolyzable group is a halogen atom such as chlorine, it is preferable that all of the hydrolyzable groups are hydrolyzed and do not remain in the silicone resin.
From the viewpoint of operability and easy removal of by-products, alkoxysilanes are preferable, and methoxysilane or ethoxysilane is particularly preferable. The usable organosilicon compound is not limited to this. One or a mixture of two or more of these silane compounds may be used.

The hydrolysis of these listed hydrolyzable silane compounds is preferably carried out by the following method. That is, a silicone resin obtained by hydrolyzing a hydrolyzable silane compound in an aqueous solution has a feature that it hardly contains a hydrolysis residue and contains abundant silanol groups. When the hydrolysis is carried out under hydrophilic conditions containing substantially no organic solvent, a unique silicone resin rich in structure and containing a large amount of T-2 units, which characterizes the present invention, is obtained. This silicone resin is prepared through the following steps.

First, the first step is a step of hydrolyzing and condensing the above-mentioned various hydrolyzable organic silane compounds in an aqueous solution having a pH of 1 to 7. The amount of water used for the hydrolysis is 50 to 50 with respect to 100 parts by weight of the silane compound or the mixture thereof, which is blended in a composition satisfying the above conditions.
It is better to use 0 parts by weight. When the amount is less than 50 parts by weight, the amount of water in the reaction system is small, so that it is difficult to control the reactivity of the silanol group described above, and it may not be possible to impart structure. On the other hand, if it exceeds 500 parts by weight, the silane concentration of the raw material may be too low, and the condensation reaction may be delayed.
The hydrolysis is carried out by adding a silane compound to the aqueous solution and stirring the mixture, but a hydrolysis catalyst may be added in order to promote the hydrolysis, particularly the initial hydrolysis. The hydrolysis catalyst may be added to the aqueous solution before adding the silane compound, or may be added to the dispersion after dispersing the silane compound. As the hydrolysis catalyst, a conventionally known catalyst can be used, and it is preferable to use one in which the added aqueous solution shows acidity at pH = 1 to 7. Particularly preferred are acidic hydrogen halides, carboxylic acids, sulfonic acids, acidic or weakly acidic inorganic salts, and solid acids such as ion exchange resins.
Specific examples include hydrogen fluoride, hydrochloric acid, nitric acid, sulfuric acid, acetic acid, organic acids represented by maleic acid, methylsulfonic acid, and cationic resins having a sulfonic acid group or a carboxylic acid group on the surface. When a hydrolysis catalyst is used, the amount added is preferably in the range of 0.001 to 10 mol% based on 1 mol of the hydrolyzable group on the silicon atom.

On the other hand, as the radical polymerizable vinyl monomer which is used together with the silicone resin to form the acrylic emulsion composition containing the silicone resin, known ones can be used. Examples thereof include (a) acrylic acid or (Meth) acrylic acid esters such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, octyl, 2-ethylhexyl, lauryl, stearyl or cyclohexyl esters of methacrylic acid, (b) acrylic acid, methacrylic acid, maleic anhydride and the like A vinyl monomer containing a carboxyl group or its anhydride, (c) 2
-Hydroxyethyl (meth) acrylate, hydroxyl group-containing vinyl monomers such as 2-hydroxypropyl (meth) acrylate, (d) (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N An amide group-containing vinyl monomer such as butoxymethyl (meth) acrylamide and diacetone (meth) acrylamide; (e)
Amino group-containing vinyl monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; (f) alkoxyl group-containing vinyl monomers such as methoxyethyl (meth) acrylate and butoxyethyl (meth) acrylate; (g) glycidyl Glycidyl group-containing vinyl monomers such as (meth) acrylate and glycidyl allyl ether; (h) vinyl ester monomers such as vinyl acetate and vinyl propionate; and (i) aromatic vinyl monomers such as styrene, vinyl toluene and α-methylstyrene. , (J) vinyl cyanide monomers such as (meth) acrylonitrile, (k) vinyl halide monomers such as vinyl chloride and vinyl bromide, (l) divinylbenzene, allyl (meth) acrylate, ethylene glycol Vinyl monomer containing two or more radically polymerizable unsaturated groups in one molecule such as di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and the number of (m) ethylene oxide groups Is 1 to 10
Zero (poly) oxyethylene chain-containing vinyl monomer such as (poly) oxyethylene mono (meth) acrylate, (n) dimethylpolysiloxane containing (meth) acryloxypropyl group at one end, styryl group at one end Alternatively, it has a radical polymerizable functional group at one terminal such as dimethylpolysiloxane containing an α-methylstyryl group,
Diorganopolysiloxane having 1 to 200 siloxane units, (o) vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, 5-hexenyltrimethoxysilane, 3- (meth) acrylic Roxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxyprohillmethyldiethoxysilane, 4-vinylphenyltrimethoxy Specific examples thereof include silane compounds having a radical polymerizable functional group such as silane, 3- (4-vinylphenyl) propyltrimethoxysilane, and 4-vinylphenylmethyltrimethoxysilane.

Among them, a radical polymerizable vinyl monomer having an alkyl group having 1 to 18 carbon atoms (meth)
The content of the alkyl acrylate is 1 to 100 mol%. If the content is less than 1 mol%, characteristics such as chemical resistance may not be obtained. More preferably, 30 to 99
It is preferable to satisfy the range of mol%. When imparting properties such as solvent resistance or chemical resistance to the cured film, it is preferable to copolymerize a radically polymerizable vinyl monomer having a crosslinkable functional group, and particularly to form a siloxane bond by a condensation reaction. A silane compound containing a radical polymerizable functional group shown in (o), and a glycidyl (meth) acrylate classified into (g) having an epoxy functional group capable of crosslinking by a ring-opening reaction of a carboxylic acid / epoxy group; A glycidyl group-containing vinyl monomer such as glycidyl allyl ether is suitable, and in the present system, the resin used for the other is a silicone resin containing a silanol group, and thus a silane compound is more suitable. In this case, as the silane compound, particularly, the following general formula (2)
The hydrolyzable silane containing a vinyl polymerizable functional group represented by the following formula is used.

[0034]

Embedded image In the formula, R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ has 1 to 1 carbon atoms.
0 oxygen atoms, -COO- interposed may be an alkylene group or the like group, an arylene group, a divalent organic group such as alkylene arylene group, r represents 0, 1 or 2, R ^1, X is as above Indicates the same meaning.

Specific examples of R ⁵ include the following.

[0036]

Embedded image

The content of the above-mentioned hydrolyzable silane containing a vinyl polymerizable functional group is preferably 0.01 to 10 mol%, particularly preferably 0.1 to 5 mol%, of the whole radically polymerizable vinyl monomer. If the amount is too small, the expression of solvent resistance and chemical resistance becomes insufficient, and if the amount is too large, crosslinking may be excessively high and cracks may occur in the coating, which may be inappropriate.

When it is desired to impart lubricity to the surface, it is preferable to copolymerize a diorganopolysiloxane having a radically polymerizable functional group at one end as exemplified in (n).

The radical polymerizable vinyl monomer is added to 100 parts by weight of the silicone resin as the first component.
Used in the range of 5 to 233 parts by weight. If the amount is less than 25 parts by weight, the film-forming properties and chemical resistance may be insufficient,
If it exceeds 33 parts by weight, weather resistance and water resistance may be insufficient. More preferably, the radical polymerizable vinyl monomer is used in the range of 42 to 186 parts by weight.

The acrylic emulsion composition containing a silicone resin used in the present invention is an emulsion polymer obtained by emulsion polymerization of the above silicone resin and a radical polymerizable vinyl monomer. This emulsion polymerization is carried out using a surfactant. ,
It can be performed by using a radical polymerization initiator. In this case, as the surfactant used for the emulsion polymerization, various types of conventionally known nonionic, cationic and anionic surfactants, and reactive emulsifiers containing radically polymerizable functional groups are applicable. Nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene carboxylic acid ester, sorbitan ester, polyoxyethylene sorbitan ester, and cationic interface such as alkyltrimethylammonium chloride and alkylbenzylammonium chloride Surfactant, anionic surfactant such as alkyl or alkyl allyl sulfate, alkyl or alkyl allyl sulfonate, dialkyl sulfosuccinate, amphoteric surfactant such as amino acid type, betaine type, etc. 27347
Of radical polymerizable (meth) acrylates, styrene, and maleic acid ester compounds containing a hydrophilic group such as a sulfonate, a polyoxyethylene chain, and a quaternary ammonium salt in the molecule described in the publication Various reactive surfactants including derivatives can be shown. One or more of these surfactants may be used.
The surfactant is preferably used in an amount of 0.5 to 15% by weight of the active ingredient, particularly preferably 1 to 10% by weight. In particular, from the viewpoint of ensuring the stability of the emulsion,
It is preferable to use the above-mentioned reactive surfactant for part or all of the surfactant used.

Next, examples of the radical polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide solution, t-butyl hydroperoxide, t-butyl peroxymaleic acid, succinic peroxide, and the like. ,
Water-soluble types such as 2'-azobis-2- [2-N-benzylamidino] propane hydrochloride, benzoyl peroxide, cumene hydroperoxide, dibutyl peroxide, diisopropylperoxydicarbonate, cumylperoxy neodecanoate And oil-soluble types such as cumyl peroxy octoate and azoisobutyronitrile, and redox systems in which a reducing agent such as sodium acid sulfite, Rongalit, and ascorbic acid are used in combination. The amount of the polymerization initiator used is 0.1 to 10% by weight based on the radical polymerizable vinyl monomer.
It may be used, and preferably 0.5 to 5% by weight.

The method for producing the emulsion composition will be described in more detail. Suitable methods are roughly classified into the following two methods.

In the first method, the organic solvent is distilled off from the solely water-insoluble silicone resin solution containing a silanol group in the first step, and only the active ingredient is substantially removed. The silicone resin from which the silicone resin has been removed is added and dissolved in a radically polymerizable vinyl monomer compound to form a solution thereof. The silicone resin-containing vinyl monomer solution prepared in the second step using a surfactant in the third step is used as the solution. This is a method in which emulsion polymerization is performed to form an emulsion.
In the step of distilling off the solvent, the highly active silanol groups are preserved, so it is preferable to remove them at as low a temperature as possible. Therefore, this method is suitable when a silicone resin having a relatively low silanol group content and excellent stability is used because the organic solvent is once separated. If necessary, a so-called solvent substitution method may be employed in which the organic solvent is distilled off in the presence of a relatively high-boiling radical polymerizable vinyl monomer, and the radical polymerizable vinyl monomer is used instead of the solvent. Various methods known in the art, such as a batch charging method in which emulsion polymerization is performed at a time and then polymerization, and a monomer addition method in which polymerization is performed while continuously adding a radical polymerizable vinyl monomer-containing solution or an emulsion thereof, are used. Is applicable. Further, a seed polymerization method in which a part of the emulsion is polymerized in advance and then the remaining emulsion is added, and a core / shell polymerization method in which the monomer composition of the core and the shell is changed can be applied.

As the emulsion of the radical polymerizable vinyl monomer-containing solution, it is preferable to add the radical polymerizable vinyl monomer-containing solution to an aqueous surfactant solution and emulsify using a homomixer or a high-pressure homogenizer. Emulsion polymerization is completed at a temperature of 10 to 90C, preferably 30 to 80C, usually for 3 to 8 hours.

The second method comprises the following steps: (i) a step of hydrolyzing a hydrolyzable silane compound in an aqueous solution having a pH of 1 to 7 to obtain a reaction mixture containing the above silanol group-containing silicone resin. (Ii) removing hydrolysis by-products from the reaction mixture out of the system to form a system mainly containing a silanol group-containing silicone resin and water;
(Iii) A radical polymerizable vinyl monomer is added to the above-mentioned system mainly composed of a silanol group-containing silicone resin and water, and the silanol group-containing silicone resin is dissolved in the above-mentioned vinyl monomer. A method of obtaining an emulsion composition by a step of removing a layer and (iv) a step of emulsion-polymerizing the silicone resin-containing radically polymerizable vinyl monomer solution in the presence of a surfactant. More specifically, this second method comprises:
In the first step, the hydrolyzable silane compound is hydrolyzed in water and further subjected to condensation polymerization to obtain a reaction mixture containing the silicone resin of the above formula (1) containing a silanol group at a molecular terminal. From the reaction mixture, an organic solvent such as alcohol by-produced by hydrolysis and other hydrolysis by-products are distilled off to obtain only the silanol group-containing silicone resin component of the formula (1) and water. Add a radically polymerizable vinyl monomer compound, dissolve the silicone resin present in a dispersed or insoluble state in the aqueous system into the vinyl monomer compound, and separate from the aqueous layer as a radically polymerizable vinyl monomer solution containing the silicone resin,
Further, the method is a method in which a surfactant is used in the fourth step to emulsion-polymerize the silicone resin-containing radically polymerizable vinyl monomer solution prepared in the third step. In this method, since there is no state in which the silicone resin alone exists in the middle of the process, it is possible to suppress condensation of silanol groups having a high reaction activity. Therefore, this method is suitable for a silicone resin rich in silanol groups but insoluble in water. In addition, the silicone resin hydrolyzed and condensed in water has a higher hardness, gives a highly flexible film, and is excellent in curability as compared with a silicone resin having the same composition prepared in an organic solvent. Therefore, it is a preferred method,
In the present invention, it is preferable to use the emulsion composition obtained by the second method. The silicone resin-containing acrylic emulsion composition can be prepared by various conventionally known methods, but the above-mentioned silicone resin-containing acrylic emulsion composition is completely different from the conventional one. That is, by forming the silicone resin produced by the hydrolysis / condensation method as described above and an acrylic resin by the emulsion polymerization method as described above, a uniform, highly transparent and dense coating film is formed. This is the first time that it has become possible.

Here, the above-mentioned emulsion composition is used for hydrolyzing a hydrolyzable silane compound from a solution of a silicone resin which has been polycondensed to a level which is insoluble in water by itself before the emulsion polymerization is carried out. By removing as much as possible the organic solvent including the produced alcohol and the like, and further converting it to a solution of a radically polymerizable vinyl monomer in a system to which a small amount of a film forming aid is added, and subjecting it to emulsion polymerization,
An emulsion substantially free of a low-boiling organic solvent such as methanol or an aromatic organic solvent represented by toluene, which has been frequently used as a solvent for a silicone resin, can be obtained. The phrase “substantially not contained” means that the content is 5% by weight or less, more preferably 2% by weight or less, based on 100 parts by weight of the total amount of the silanol group-containing silicone resin and the radical polymerizable vinyl monomer.

In the present invention, the silicone-acrylic resin composite film forming the first layer comprises the above silicone resin-containing acrylic emulsion composition as a main component, a curing catalyst,
It can be formed by curing a material containing a film forming aid, a preservative, an antifreezing agent and the like. As the curing catalyst, a conventionally known condensation catalyst can be used. For example, basic compounds such as lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, sodium formate, n-hexylamine, tributylamine, diazabicycloundecene; tetraisopropyl titanate, tetraisopropyl Butyl titanate, aluminum triisobutoxide, aluminum triisopropoxide, aluminum acetylacetonate, aluminum perchlorate, aluminum chloride, cobalt octylate, cobalt acetylacetonate, iron acetylacetonate, tin acetylacetonate, dibutyltin octane And metal-containing compounds such as dibutyltin laurate; acidic compounds such as p-toluenesulfonic acid and trichloroacetic acid; and emulsions thereof.

The film forming aid is soluble in water, and remains in the film even after most of the water is vaporized, and maintains high leveling properties by imparting fluidity to the film until it is completely cured. It works like that. This is particularly effective when the acrylic polymer formed has a high glass transition point. Therefore, all those soluble in water and having a boiling point of 100 ° C. or higher are included, and 1-butanol, isobutyl alcohol, 2-pentanol, 3-pentanol, isopentyl alcohol, methyl lactate, ethyl lactate, and 3-methyl-
Alcohols such as 3-methoxybutanol, 1,2-propanediol, 1,3-butanediol, 4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4- Pentanediol, glycerin, polyols such as trimethylolpropane,
2-butoxyethanol, 2-phenoxyethanol,
Ethylene glycol derivatives such as 2-ethoxyethyl acetate, 2-butoxyethyl acetate, diethylene glycol monobutyl ether acetate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-methoxy-2-methylethyl acetate Start, 1-
Propylene glycol derivatives such as ethoxy-2-methylethyl acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether acetate, and butylene glycol derivatives such as 3-methoxybutyl acetate And esters such as butyl acetate, isobutyl acetate, γ-butyrolactone, propylene carbonate, and dibutyl phthalate. Particularly, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, diethylene glycol monobutyl ether acetate, 1-ethoxy-2-methylethyl acetate, dipropylene glycol monomethyl ether acetate, and the like are preferable from the viewpoint of leveling properties. These organic solvents are
Since it is inferior in water solubility to low boiling alcohols such as methanol and ethanol, it does not impair the stability of the emulsion and contributes only to the formation of a uniform film. This film forming aid may be added to the vinyl monomer solution before the emulsion polymerization, or may be added to the emulsion after the emulsion polymerization, and the action is not changed. The addition amount is preferably from 0 to 20 parts by weight based on 100 parts by weight of the total of (silanol containing silicone + radical polymerizable vinyl monomer). If it is added in excess of 20 parts by weight, the amount of the film-forming aid remaining in the film even after the completion of curing becomes large, and the properties of the film become insufficient, which is not preferable. More preferably, 5-2
This is the case where the range of 0 parts by weight is satisfied. A more preferred range is 5 to 15 parts by weight.

The above emulsion composition has a pH
May be added, such as a combination of an acid and a basic compound serving as a buffering agent for adjusting the pH, such as acetic acid and sodium acetate, disodium hydrogen phosphate and citric acid. In addition, extenders, colored pigments, anticorrosive pigments, dyes, leveling agents, and the like can be used for the purpose of imparting excellent coating performance. In this case, the emulsion composition has a pH of 3 to 9, especially 4
It is preferable to adjust to ８8.

In the present invention, a second layer of the photocatalyst-containing layer is formed on the first layer of the silicone-acrylic resin composite film.

Here, as the photocatalyst used for the second layer,
Particles which are present on the surface of the coating film and have a high photocatalytic activity that can change the surface to hydrophilic by receiving sunlight are used. Titanium oxide is preferable as a photocatalyst having high activity, considering that it is chemically stable and inexpensive. The particle type of titanium oxide does not matter. As the titanium oxide particles, besides a sol dispersed in a dispersion medium, a paste or powder containing water and a solvent can be used. As the dispersion medium of the sol, water, alcohols such as methanol, ethanol, isopropanol, n-butanol and isobutanol, and ketones such as methyl ethyl ketone and methyl isobutyl ketone are preferable. The photocatalytic activity of titanium oxide is higher as the average particle size of the particles is smaller, and it is preferable to use those having a particle size of 0.1 μm or less. The average particle size referred to here is the Scherrer based on the integration width of the maximum peak of the crystal when X-ray diffraction is performed for powder.
It is a value obtained by the formula, and in the case of a dispersion, a value measured by a dynamic light scattering method.

These photocatalytically active particles may agglomerate under the influence of a dispersion medium or the like, resulting in poor dispersion stability. In this case, it is possible to partially stabilize the surface by performing a surface treatment. The surface treatment is achieved by adding hydrolyzable silicon, aluminum, zirconium or the like to modify the surface of the particles. However, if the entire surface of the particles is covered, the photocatalytic activity is suppressed, so that the surface treatment must be partially performed, and the film is only sufficiently developed to exhibit the antifouling property of the film.

As the coating liquid for forming the second photocatalyst-containing layer, a liquid in which fine particles of the photocatalyst are dispersed in water and / or an organic solvent can be used. Examples of the organic solvent include alcohols such as methanol, ethanol, and isopropyl alcohol, ketones such as acetone and methyl ethyl ketone, and other esters, ethers, and dimethylformamide. It is possible to contain a silicone resin in order to firmly bond with the first layer and increase the durability as a coating film. In this case, the content ratio of the photocatalyst to the silicone resin can be arbitrarily determined, but preferably the photocatalyst is 10 to 10 parts by weight of the silicone resin in solid content.
It is preferred to use 400 parts by weight. In addition, as the silicone resin, the above-described silicone resin can be used, but is not limited thereto, and a known silicone resin can be used.

The second layer formed from a mixed solution of the photocatalytic titanium oxide and the silica dispersion is preferable because it tends to quickly develop hydrophilicity. In this case, the titanium oxide photocatalyst is 40 to 190 parts by weight based on 100 parts by weight of silica
It is preferable to use 0 parts by weight.

Furthermore, the photocatalyst particles originally exhibit a deodorizing power and an antibacterial power due to a strong oxidizing power generated by light irradiation.
To further enhance these functions, silver, copper, platinum, gold,
A substance containing one or more metal elements selected from palladium, iron, nickel, and zinc can be contained. The content of the substance containing such a metal element must be such that the physical properties of the film such as hardness and flexibility are not affected, and is preferably 20 parts by weight or less based on 100 parts by weight of titanium oxide.

As described above, it is considered that the oxidizing ability and the hydrophilizing ability of the photocatalytic titanium oxide are expressed by different principles, but it is extremely difficult to treat both clearly. It is. If an organic substance such as oil adheres to the hydrophilic surface, the contact angle naturally increases, but if the organic substance is decomposed by radical species generated by the photocatalyst,
This is because hydrophilicity can be maintained for a long period of time, and it is considered that this greatly contributes to the antifouling property of the coating film surface.

In the coating film of the present invention, the thickness of the coating film is appropriately selected, but the thickness of the first layer is 0.01 to 100 μm, particularly 0.1 μm.
It is preferably 1 to 50 μm, and the second layer has a thickness of 0.1 μm.
It is preferably 5 μm or less, particularly preferably 0.1 μm or less.

The method for forming the coating film is not limited, but the following steps can be adopted. That is, a step of applying a coating liquid capable of forming a silicone-acrylic resin composite film such as the emulsion composition to a substrate as a first layer,
A step of partially or completely curing the applied film by air drying or heat curing, a step of applying a photocatalyst-containing coating solution on the silicone resin layer, and drying or heating at room temperature to fix the photocatalyst to the first layer. Alternatively, it is achieved by sequentially performing a step of forming a second layer by crosslinking a silicone resin to form a photocatalyst-containing coating film.
In order to improve the adhesion between the substrate and the first layer of the silicone-acrylic resin composite film, a primer layer may be formed, or the surface of the substrate may be subjected to a treatment such as corona discharge. Examples of the method of applying to the substrate include a spray coating method, a roll coating method, a dip coating method, and a spin coating method, and any of these methods may be used, or any other method may be used. Regarding the method of curing the coating film, the film may be left in the air and air-dried, or may be heated. The heating temperature, time and the like are not limited, but usually, a cured coating film is formed by heating from room temperature to 250 ° C. for 10 minutes to 2 hours. By adjusting the curing conditions of the first layer and partially forming an uncrosslinked film, it is possible to improve the adhesion to the second layer. In this case, specifically, by curing the first layer at 80 to 130 ° C. for about 1 to 10 minutes, the second layer is applied while being partially cured while not being tacky. After that, by curing, the photocatalyst is partially embedded so that a coating film having excellent hardness and adhesiveness can be obtained. When these coating films are irradiated with light including ultraviolet rays such as sunlight, the contact angle of the surface with water drops to 60 degrees or less, and in some cases, 20 degrees or less in several days, and becomes hydrophilic. When the contact angle exceeds 60 degrees, the effect of removing pollutants by rainwater does not function sufficiently, and the expected antifouling property is not exhibited. As the light containing ultraviolet light, any light source having a wavelength of 400 nm or less can be used, regardless of the intensity, etc., for example, ultraviolet light in the atmosphere such as sunlight or ultraviolet light of a fluorescent lamp, An ultraviolet generator such as an ultraviolet lamp can be used.
Therefore, in a place where sunlight is applied, the surface of the coating film is hydrophilized within several days to several weeks. Minimum 1 for indoor use
It is preferable to irradiate light containing ultraviolet light of μW / cm ² . If it is 1 μw / cm ² or less, surface hydrophilization may not be achieved or it may take an extremely long time.

[0059]

According to the present invention, a silicone-acrylic resin composite film containing a silicone resin in an amount of 30 to 80% by weight based on the total resin solid content is formed on the undercoat layer of the first layer, and a photocatalyst-containing layer is formed thereon. Is formed, it is possible to achieve both weather resistance, adhesion to a substrate, flexibility, and alkali resistance. In addition, this coating film is exposed to sunlight and the coating film surface exhibits hydrophilicity, and can maintain antifouling property and antibacterial property for a long time.

In this case, by using the above-mentioned silicone resin-containing acrylic emulsion composition for the first layer, this is a water-dispersed emulsion paint, which takes into consideration the global environment, safety, worker's health, etc. And, unlike conventional silicone-acrylic resin paints,
By controlling the molecular structure of the silicone resin, a transparent and uniform silicone-acrylic resin composite film can be formed while keeping the content of the silicone resin high.

[0061]

EXAMPLES The present invention will be described in detail with reference to Preparation Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, in the following examples, a part shows a weight part.

[Preparation Example 1] 408 g (3.0 mol) of methyltrimethoxysilane was charged into a 2 L flask, and 800 g of water was added at 0 ° C. under a nitrogen atmosphere and mixed well.
Here, 216 g of a 0.05N aqueous hydrochloric acid solution was added under ice cooling to 4 g.
The hydrolysis reaction was performed by dropping over 0 minutes. After completion of the dropwise addition, the mixture was stirred at 10 ° C. or lower for 1 hour, and then stirred at room temperature for 3 hours to complete the hydrolysis reaction. Next, methanol and water produced by the hydrolysis were distilled off under reduced pressure at 70 ° C. × 60 Torr for 1 hour to obtain 1136 g of a solution. The solution became cloudy and separated into two layers when left standing overnight. The silicone resin insoluble in water settled.

A portion of the cloudy solution was sampled, and the water-insoluble silicone resin was dissolved using methyl isobutyl ketone and separated from the aqueous layer. After dehydration treatment, T
The solvent was replaced by HF, and methyl Grignard was reacted to determine the silanol group. As a result, the content of the silanol group was 11.0% by weight (based on the silicone resin). G
As a result of PC measurement, the number average molecular weight of this silicone resin was 1.8 × 10 ³ .

The structure of the silanol group-containing silicone resin was determined by infrared absorption spectrum (IR) analysis and nuclear magnetic resonance spectrum ( ²⁹ Si NMR) analysis.
In the infrared absorption spectrum of the film obtained by removing the solvent by air drying, while broad absorption derived from silanol groups around the 3200 cm ^-1 is observed, the carbon of the methoxy group - around 2840cm ^-1, which derived from the stretching vibration of the hydrogen bond No absorption was observed. Alternatively, an attempt was made to distill and quantify the residual methoxy group by the alkali cracking method, but no methanol was detected, confirming the results of the infrared absorption spectrum analysis. From this result, it was determined that the methoxy group was completely hydrolyzed.

In the ²⁹ Si NMR analysis, each structure of the T unit shown below can be distinguished from the difference in the position of the appearing chemical shift. T-1 unit CH ₃ -Si (-O-Si≡) ₁ (-OH) ₂ -46 to 48 ppm T-2 unit CH ₃ -Si (-O-Si≡) ₂ (-OH) ₁ -54 to 58 ppm T-3 units _{CH 3 -Si (-O-Si≡)} 3 -62~68ppm

The silanol group-containing silicone resin ²⁹
When Si NMR analysis was performed, T-1 unit was 2 mol%, T-2 unit was 42 mol%, and T-3 unit was 56 mol%.
I knew it did. From the above analysis results, the obtained silicone resin can be represented by the following average composition formula.

(CH ₃ ) _1.0 Si (OH) _0.44 O _1.28 The silanol group content calculated from this composition formula is 10.
It was 5% by weight, which was in good agreement with the actually measured value.

Next, 210 g of methyl methacrylate (MMA) and 90 g of butyl acrylate (BA) were added to this aqueous solution.
g was added, and the precipitated silicone resin was dissolved and separated from the aqueous layer as a silicone resin-containing MMA / BA solution.
To the solution after separation, 500 g of water was added, and the mixture was sufficiently stirred and mixed for 10 minutes, and then allowed to stand, and the aqueous layer was separated. When methanol contained in the organic layer was quantified by GC, 0.2% by weight was detected in this solution. Finally, 505 g of an MMA / BA solution (A) having a nonvolatile content of 40.2% by weight (105 ° C. × 3 hours) was obtained.

[Preparation Example 2] In Preparation Example 1, 388 g (2.85 mol) of methyltrimethoxysilane and 18 g (0.15 mol) of dimethyldimethoxysilane were used instead of methyltrimethoxysilane, and 400 g of water was used. 1
The preparation was carried out in the same manner as in Preparation Example 1, except that the mixture was hydrolyzed using 4 g of N acetic acid aqueous solution and changed to separate from the aqueous layer using 110 g of MMA and 110 g of BA instead of 210 g of MMA and 90 g of BA.

When the obtained silanol group-containing silicone resin was analyzed in the same manner, it contained 38 mol% of T-2 units and had a number average molecular weight of 1.5 × 10 ³ . The average composition formula is represented as follows.

(CH ₃ ) _1.05 Si (OH) _0.40 O _{1.28 The} amount of silanol groups was 9.6% by weight.

Finally, a nonvolatile content of 49.7% (105 ° C.)
X 3 hours) to obtain 411 g of an MMA / BA mixed solution (B).

[Preparation Example 3] Water 1300 was placed in a 5 L flask.
g, 200 g of methanol and 800 g of toluene.
With stirring at room temperature, 89.7 methyltrichlorosilane.
g (0.6 mole) and phenyltrichlorosilane.
6 g (2.4 mol) of the mixture was added dropwise over 1 hour and hydrolyzed. Further, the mixture was stirred at 30 ° C. for 3 hours to complete the hydrolysis. Thereafter, the mixture was allowed to stand, and an aqueous layer containing hydrochloric acid was separated and removed. Then, 1 L of water was added to the remaining organic layer, and the mixture was stirred for 10 minutes, allowed to stand, and then washed twice with separation and removal of the aqueous layer. The organic solvent was distilled off under reduced pressure of the obtained silicone resin solution at 50 ° C. × 50 Torr to obtain 329 g of a powdered silicone resin.

When the obtained silanol group-containing silicone resin was analyzed in the same manner, 1 mol% of T-1 unit was obtained.
Contains 2 mol% of 2 units and has a number average molecular weight of 1.9 × 1
0 was ^3. The amount of silanol groups was 2.6% by weight. The average composition formula is represented as follows.

(C ₆ H ₅ ) _0.80 (CH ₃ ) _0.2 Si (OCH
₃ ) _0.07 (OH) _0.40 O _1.27 Methyl methacrylate (MMA) 2
00g and 23 g of butyl acrylate (BA) were added, and finally MM with a non-volatile content of 59.0% (105 ° C. × 3 hours)
552 g of A / BA solution (C) was obtained.

[Preparation Example 4] In a polymerization vessel equipped with a stirrer, a condenser, a thermometer and a nitrogen gas inlet, 730 parts of deionized water and 0.47 of sodium carbonate as a pH buffer were used.
And 4.70 parts of boric acid, and the mixture was heated to 60 ° C. while stirring and then replaced with nitrogen. Rongalite 1.75
Parts, 0.12 parts of a 1% aqueous solution of disodium ethylenediaminetetraacetate, and 0.04 parts of a 1% aqueous solution of ferrous sulfate, and at the same time, the silicone resin-containing MM obtained in Preparation Example 1 was added.
700 parts of A / BA solution (A), 7 parts of γ-methacryloxypropylmethyldimethoxysilane, 2.1 parts of t-butyl hydroperoxide (69% pure content), reactive surfactant Aqualon RN-20 (No. Manufactured by Issei Pharmaceutical Co., Ltd./
A mixture of 14.0 parts (trade name) and 7.0 parts of Aqualon HS-10 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added while maintaining the temperature in the polymerization vessel at 60 ° C. It was added uniformly over 5 hours, and further reacted at 60 ° C. for 2 hours to complete the polymerization. To this, 40 parts of 2-butoxyethyl acetate was added, and the mixture was sufficiently stirred and mixed.
m-1) was completed.

The solid content of the obtained emulsion Em-1 was 50.1%, and the pH was adjusted to 7.0 by adding aqueous ammonia.

[Preparation Example 5] 700 parts of the silicone resin-containing MMA / BA mixed solution (B) obtained in Preparation Example 2, 7 parts of γ-methacryloxypropylmethyldimethoxysilane, and a reactive interface were placed in a glass beaker. Activator Aqualon RN-20 (Daiichi Kogyo Seiyaku Co., Ltd./trade name) 14.0
Parts, 7.0 parts of Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd./trade name) and 70 parts of 2-butoxyethyl acetate, and stirring with a high-speed stirrer, deionized water 43
The emulsion was formed while slowly adding 0 g.

In a polymerization vessel equipped with a stirrer, a condenser, a thermometer and a nitrogen gas inlet, 230 parts of deionized water,
0.47 parts of sodium carbonate and 4.70 parts of boric acid were charged as a pH buffer, and the temperature was raised to 60 ° C. while stirring, followed by purging with nitrogen. 1.75 parts of Rongalite, 0.12 part of a 1% aqueous solution of disodium ethylenediaminetetraacetate,
At the same time as adding 0.04 parts of a 1% aqueous solution of ferrous sulfate, the emulsion prepared above was uniformly added over 2.5 hours while maintaining the temperature in the polymerization vessel at 60 ° C. For 2 hours to complete the polymerization.

The solid content of the obtained emulsion (Em-2) was 49.9%.
H was adjusted to 8.0.

[Preparation Example 6] MMA containing silicone resin /
Instead of BA mixed solution (B), silicone resin containing M
Except for using the MA / BA solution (C), emulsion polymerization was carried out in the same manner as in Preparation Example 5 to obtain an emulsion (Em-3).
Was synthesized. The solids concentration of this emulsion was 49.2.
%, And the pH was adjusted to 8.0 by adding aqueous ammonia.

[Comparative Preparation Example 1] In Preparation Example 1, instead of 210 g of methyl methacrylate (MMA) and 90 g of butyl acrylate (BA), 500 g of methyl methacrylate (MMA) and butyl acrylate (BA) 1
After adding 3 g, the silicone resin was dissolved and separated from the aqueous layer, and finally, a nonvolatile content of 24.6% by weight (10%) was added.
510 g of an MMA / BA solution (D) (5 ° C. × 3 hours) was obtained.

Comparative Preparation Example 2 In Preparation Example 1, butyl acrylate (B) was used instead of 210 g of methyl methacrylate (MMA) and 90 g of butyl acrylate (BA).
A) By adding 40 g, dissolving the silicone resin and separating from the aqueous layer, 85.6% by weight of the non-volatile content was finally obtained.
(105 ° C. × 3 hours) to obtain 250 g of a BA solution (E).

[Comparative Preparation Examples 3 and 4] Instead of the silicone resin-containing MMA / BA mixed solution (B), a silicone resin-containing MMA / BA solution (D) or BA solution (E)
The emulsion (Em-4, 5) was obtained by emulsion polymerization in the same manner as in Preparation Example 5 except that The solid concentration of this emulsion was 48.8% for Em-4,
It was 50.2% at -5, and both were adjusted to pH 8.0 by adding aqueous ammonia.

[Examples 1 to 6, Comparative Examples 1 to 4] An acrylic film (AF) and a glass plate (GL) were used as substrates, and the emulsion synthesized in the preparation example was applied and cured under the conditions shown in Table 1. Then, after the first layer, a 4: 1 mixed sol of a water-dispersed titania sol (manufactured by Nissan Chemical Industries, Ltd., TA-15 (solid content: 15%) and a methanol-dispersed silica sol (solid content: 15%)) was diluted 8-fold with ethanol. The solution was applied and cured to form a photocatalyst-containing coating film as a second layer, the first layer was coated so as to have a thickness of 20 μm after curing, and the second layer was applied by flow coating to a thickness of about 0.2 μm. The thickness was about 0.05 to 0.1 μm.

An accelerated weathering test (2000 hours) was performed on these coating films using a sunshine carbon weather meter, and the appearance of the coating film before and after the test, the water contact angle on the surface,
The adhesion was compared. Regarding the appearance of the coating film, a state without any white turbidity was evaluated as ○, and a state where white turbidity and yellowing occurred was evaluated as x. For the adhesion, a cross-cut test was performed using a cellophane tape, and those that were completely adhered were evaluated as good, and those that were peeled off at least one of the substrate and the first layer or the first layer and the second layer were evaluated as ×.
It was determined.

As a result, in the case where Em-4 having a silicone resin content of 25% by weight was used for the first layer and the case where Em-5 having a silicone resin content of 82% by weight was used, in both cases, Peeling and detachment occurred, and the contact angle of the coating film after the test was 50 degrees or more, and the hydrophilicity could not be maintained. In contrast, the silicone resin content is 30 to 80
Em-1 to 3 in the range of wt% also had good coating film appearance, and hydrophilicity was maintained for a long period of time.

[0088]

[Table 1]

────────────────────────────────────────────────── ─── Continuing on the front page (72) Akira Yamamoto, Inventor 1-10, Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Inside the Silicone Electronics Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (56) References JP-A-9-171707 ( JP, A) JP-A-7-171408 (JP, A) JP-A-4-89813 (JP, A) JP-A-7-286129 (JP, A) JP-A 8-27347 (JP, A) JP-A-8-3409 (JP, A) JP-A-8-60098 (JP, A) JP-A-6-344665 (JP, A) JP-A-10-237769 (JP, A) JP-A-10-315374 (JP) JP-A-11-207871 (JP, A) JP-A-10-225658 (JP, A) WO 96/14932 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) B32B 1/00-35/00 C08F 283/12

Claims (9)

(57) [Claims] 1. A first layer comprising a silicone-acrylic resin composite film containing 30 to 80% by weight of a silicone resin based on the total resin solid content on a substrate, and a second layer comprising a photocatalyst-containing layer thereon. _Are formed, and the silicone-acrylic resin composite film has the following (1) average composition formula (1): R ¹ _m R ² _n Si (OH) _p (X) _q O _{(4-mnpq) / 2} (1 (Wherein, R ¹ represents an unsubstituted monovalent hydrocarbon group, R ² represents a substituted monovalent hydrocarbon group, X represents a hydrolyzable group, and m, n, p, and q represent 0.5 ≦ m ≦ 1). 0.8, 0 ≦ n ≦ 1.0, 0 <p ≦ 1.5, 0 ≦ q ≦ 0.5, 0.5 ≦ m + n ≦ 1.8, and 0 <p + q ≦ 1.5 ), And contains 30 to 100 mol% of a structural unit (T unit) represented by the formula R ³ —SiZ ₃ , and among the T units, the formula R ³ —Si (OH) Z ′ Represented by ₂ 30 to 80 mol% of a structural unit containing one silanol group (T-2 unit) (wherein R ³ represents a substituted or unsubstituted monovalent hydrocarbon group; Represents an OH group, a hydrolyzable group or a siloxane residue, and Z ′ represents a siloxane residue.); 100 parts by weight of a water-insoluble silanol group-containing silicone resin having a number average molecular weight of 500 or more; 2) A water-based polymer containing, as a main component, 25 to 233 parts by weight of a radical polymerizable vinyl monomer having a content of an alkyl ester (meth) acrylate having an alkyl group having 1 to 18 carbon atoms of 1 to 100 mol%. An article having a hydrophilic coating film, which is a cured product of a silicone resin-containing acrylic emulsion composition comprising an emulsion polymer. 2. The article according to claim 1, wherein the content of a methyl group in all organic substituents bonded to silicon atoms in the silanol group-containing silicone resin is 50 mol% or more. 3. A silicone-acrylic resin composite film comprising: (i) a hydrolysis reaction of a hydrolyzable silane compound in an aqueous solution having a pH of 1 to 7 and containing the silanol group-containing silicone resin according to claim 1 or 2; A step of obtaining a mixture, (ii) a step of removing a hydrolysis by-product from the reaction mixture out of the system to form a system mainly containing a silanol group-containing silicone resin and water, and (iii) the above-mentioned mainly silanol group-containing silicone resin. And water, the content of an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms is 1 to
A step of adding 100 mol% of a radical polymerizable vinyl monomer, dissolving the silanol group-containing silicone resin in the vinyl monomer, and removing the remaining layer composed of a hydrolysis by-product and water; (iv) containing the silicone resin The article according to claim 1 or 2, which is a cured product of a silicone resin-containing acrylic emulsion composition obtained by a step of emulsion-polymerizing a radically polymerizable vinyl monomer solution in the presence of an aqueous surfactant solution. 4. A radically polymerizable vinyl monomer represented by the following general formula (2): (Wherein, R ⁴ is a hydrogen atom or a methyl group, and R ⁵ is
The divalent organic group of 10, R ¹ and X have the same meaning as described above, and r is 0, 1 or 2. ) 0.01 to 10 mol% of the vinyl polymerizable functional group-containing hydrolyzable silane represented by
The article according to claim 1, wherein the article is contained. 5. The article according to claim 1, wherein the photocatalyst-containing layer is a layer containing 40 to 1,900 parts by weight of titanium oxide photocatalyst based on 100 parts by weight of silica solid content. 6. On a substrate, (1) the following average composition formula (1): R ¹ _m R ² _n Si (OH) _p (X) _q O _{(4-mnpq) / 2} (1) R ¹ represents an unsubstituted monovalent hydrocarbon group, R ² represents a substituted monovalent hydrocarbon group, X represents a hydrolyzable group, and m, n, p, and q are 0.5 ≦ m ≦ 1.8, 0 ≦ n ≦ 1.0, 0 <p ≦ 1.5, 0 ≦ q ≦ 0.5, 0.5 ≦ m + n ≦ 1.8, and 0 <p + q ≦ 1.5.) And 30 to 100 mol% of a structural unit (T unit) represented by the formula R ³ —SiZ ₃ , and among these T units, represented by the formula R ³ —Si (OH) Z ′ ₂ 30 to 80 mol% of a structural unit (T-2 unit) containing one silanol group (provided that R ³ represents a substituted or unsubstituted monovalent hydrocarbon group, and Z represents OH group, hydrolyzable group or siloxane residue, Z 'is Loxane residue.), 100 parts by weight of a water-insoluble silanol group-containing silicone resin having a number average molecular weight of 500 or more, (2) alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms Applying a silicone resin-containing acrylic emulsion composition comprising an aqueous emulsion polymer containing, as a main component, 25 to 233 parts by weight of a radical polymerizable vinyl monomer having an ester content of 1 to 100 mol%;
This is cured to form a first layer composed of a silicone-acrylic resin composite film containing 30 to 80% by weight of silicone resin based on the total resin solid content, and a photocatalyst containing layer is formed thereon. A method for producing an article having a hydrophilic coating film. 7. A silicone resin-containing acrylic emulsion composition comprising: (i) hydrolyzing a hydrolyzable silane compound in an aqueous solution having a pH of 1 to 7, and containing the silanol group-containing silicone resin according to claim 1 or 2. (Ii) a step of removing a hydrolysis by-product from the reaction mixture out of the system to form a system mainly containing a silanol group-containing silicone resin and water; and (iii) the above-mentioned mainly silanol group-containing silicone. In a system comprising a resin and water, the content of an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms is 1 to
A step of adding 100 mol% of a radical polymerizable vinyl monomer, dissolving the silanol group-containing silicone resin in the vinyl monomer, and removing the remaining layer composed of a hydrolysis by-product and water; (iv) containing the silicone resin The production method according to claim 6, which is obtained by a step of emulsion-polymerizing a radically polymerizable vinyl monomer solution in the presence of a surfactant aqueous solution. 8. A radical polymerizable vinyl monomer represented by the following general formula (2): (Wherein, R ⁴ is a hydrogen atom or a methyl group, and R ⁵ is
The divalent organic group of 10, R ¹ and X have the same meaning as described above, and r is 0, 1 or 2. ) 0.01 to 10 mol% of the vinyl polymerizable functional group-containing hydrolyzable silane represented by
The production method according to claim 6 or 7, wherein 9. The photocatalyst containing layer is formed from a mixture of a photocatalytic titanium oxide and a silica dispersion.
The manufacturing method as described.