JP2011131211A - Photocatalytic metal compound, photocatalytic composition, and photocatalytic coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photocatalytic metal compound which exerts necessary photocatalytic activity without damaging an under coating. <P>SOLUTION: The photocatalytic metal compound is a metal compound used for a photocatalyst in which a value of [-O<SB>2</SB><SP>-</SP>] is not more than 15 nM out of the amount of active oxygen species generated when ultraviolet rays having a wavelength of 365 nm are radiated onto a predetermined suspension containing the metal compound. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a photocatalyst metal compound, a photocatalyst composition, and a photocatalyst coating film.

In recent years, in order to impart antifouling performance to architectural outer walls such as houses and buildings, a photocatalytic coating has been put into practical use, and the photocatalytic coating is applied to the architectural outer wall to form a photocatalytic coating film. This photocatalyst coating material is mixed with a metal compound material having photocatalytic activity so as to exhibit photocatalytic activity. The most commonly used of these compounds is titanium dioxide (TiO ₂ ). When light (UV) strikes the titanium dioxide to generate excited electrons and holes by the generated excited electrons and holes, in the presence of oxygen and water at the catalyst surface, · O ₂ ^- and · OH (“·” Indicates an unpaired electron, meaning that the chemical species to which it is attached is a radical species). These active oxygen species express important photocatalytic activities such as a soil decomposition function and a nitrogen oxide removal function. However, these active oxygen species also damage the coating film (hereinafter referred to as “undercoat film”) of the base material to which the photocatalytic coating is applied. Therefore, a two-layer coat type photocatalyst coating in which a protective layer typified by a silicone resin is provided between the base coating and the photocatalytic coating has been proposed (see Patent Document 1).

JP 2003-73610 A

  Since a film such as a silicone resin used as a protective layer of a two-layer coat type photocatalyst paint is hard and brittle, it is impossible to completely prevent the occurrence of minute through cracks in the film. As a result, it was not possible to prevent the aforementioned active oxygen species from damaging the base coating film through the through cracks. Also, the two-layer coat type photocatalyst paint has difficulty in on-site workability. In order to improve these problems, a one-layer coat type photocatalyst paint that can prevent damage to the base coating film and does not require a protective layer is desired.

  The present invention realizes such a one-layer coat type photocatalyst coating material as described above, and does not damage the base coating film, and exhibits a necessary photocatalytic activity, and a photocatalyst composition containing the metal compound. It aims at providing a thing and a photocatalyst coating film.

As a result of intensive studies aimed at solving the above problems, the present inventors have reached the present invention.
That is, the present invention is as follows.
[1] A value of [• O ₂ ⁻ ] among active oxygen species generated when a predetermined suspension containing the metal compound is irradiated with ultraviolet light having a wavelength of 365 nm, which is a metal compound used as a photocatalyst. Is a metal compound for photocatalyst of 15 nM or less.
[2] A metal compound used as a photocatalyst, and among the amount of active oxygen species generated when a predetermined suspension containing the metal compound is irradiated with ultraviolet light having a wavelength of 365 nm, the value of [.OH] is 400 nM The metal compound for photocatalysts is:
[3] A metal compound used as a photocatalyst, the value of [H ₂ O ₂ ] among active oxygen species generated when a predetermined suspension containing the metal compound is irradiated with ultraviolet light having a wavelength of 365 nm Is a metal compound for photocatalyst of 0.4 nM or less.
[4] A photocatalyst composition comprising the metal compound for photocatalyst according to any one of [1] to [3] and a binder.
[5] The photocatalyst composition according to [4], wherein the binder includes polymer particles and particles of a metal oxide other than the metal compound for photocatalyst.
[6] A photocatalyst coating film formed from the photocatalyst composition of [4] or [5].
[7] A photocatalyst-coated product provided with the photocatalyst coating film of [6].

  If the metal compound for photocatalysts of the present invention is used, a photocatalyst layer that exhibits the necessary photocatalytic activity can be provided on the base coating film without damaging the base coating film, and excellent on-site workability A single-layer coating type photocatalytic coating can be provided.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. In the present specification, “(meth) acryl” means “acryl” and “methacryl” corresponding thereto, “(meth) acrylate” means “acrylate” and “methacrylate” corresponding thereto, “(Meth) acryloyl” means “acryloyl” and its corresponding “methacryloyl”.

The metal compound for photocatalyst of this embodiment is a metal compound used as a photocatalyst, and when a predetermined suspension containing the metal compound is irradiated with ultraviolet light having a wavelength of 365 nm (hereinafter referred to as “specific ultraviolet light”). The amount of [.O ₂ ⁻ ] is 15 nM or less in the amount of active oxygen species generated in In the present specification, the “predetermined suspension” means that 3.5 mL of 0.01 M NaOH aqueous solution is injected into a quartz cell (optical path (length) 1 cm × width 1 cm), and further 15 mg of a metal compound is added thereto. Is a suspension obtained by adding and stirring the powder. In order not to damage the underlying coating film, among the amount of active oxygen species generated when a specific suspension is irradiated with specific ultraviolet light, [· O ₂ ⁻ ], that is, the value of superoxide radical concentration Is preferably 15 nM or less, more preferably 10 nM or less, and even more preferably 5 nM or less. Here, the ultraviolet light means a wavelength region of 400 nm or less. NM represents nanomolar, and 1 nM = 10 ⁻⁹ M = 10 ⁻⁹ mol / L.

Of the active oxygen species, · O ₂ ^- is a radical species has the effect of damaging the coating film, resulting in hydrogen peroxide reacts further with water. This hydrogen peroxide also damages the undercoat. That is, the value of [• O ₂ ⁻ ] of 15 nM or less means a metal compound for photocatalyst in which the amount of generated • O ₂ ⁻ is small and the underlying coating does not hurt. On the other hand, a metal compound for photocatalyst having a value of [.O ₂ ⁻ ] of more than 15 nM has a large amount of • O ₂ ⁻ and damages the base coating film.

The metal compound for photocatalyst of the present embodiment has [· OH], that is, a value of hydroxyl radical of 400 nM or less, among the above active oxygen species generated when irradiated with specific ultraviolet light so as not to damage the underlying coating film. It is preferable that it is 200 nM or less, and it is still more preferable that it is 150 nM or less. Here, the ultraviolet light means a wavelength region of 400 nm or less. NM represents nanomolar, and 1 nM = 10 ⁻⁹ M = 10 ⁻⁹ mol / L.

  Of the active oxygen species, .OH is a radical species that acts to damage the coating film. That is, a value of [.OH] of 400 nM or less means that the amount of .OH generated is small and the metal film for photocatalyst does not hurt the base coating film. On the other hand, a metal compound for photocatalyst having a value of [.OH] of more than 400 nM has a large amount of .OH generation, and damages the base coating film.

The metal compound for photocatalyst of this embodiment is [H ₂ O ₂ ], that is, oxydol (hydrogen peroxide) among the above-mentioned active oxygen species generated when irradiated with specific ultraviolet light so as not to damage the undercoat. ) Is preferably 0.4 nM or less, more preferably 0.3 nM or less, and still more preferably 0.2 nM or less. Here, the ultraviolet light means a wavelength region of 400 nm or less. NM represents nanomolar, and 1 nM = 10 ⁻⁹ M = 10 ⁻⁹ mol / L.

Of the active oxygen species, H ₂ O ₂ is, · O ₂ ^- as compared with radical species, such as a stable substance, a longer life as compared with the radical species life (less than 1 second), long distance It will move and will damage the undercoat. Therefore, [H ₂ O ₂ ] is preferably smaller than the above radical species. That is, the value of [H ₂ O ₂ ] being 0.4 nM or less means that the amount of H ₂ O ₂ generated is small and the metal compound for photocatalyst does not hurt the base coating film. On the other hand, a metal compound for photocatalyst having a value of [H ₂ O ₂ ] larger than 0.4 nM has a large amount of H ₂ O ₂ generated, and damages the underlying coating film.

  The metal compound for photocatalyst of the present embodiment is such that at least two of the three kinds of active oxygen species satisfy the above-mentioned condition of the amount of active oxygen species from the viewpoint of more effectively and reliably achieving the effects of the present invention. Preferably, it is more preferable that all three types satisfy the above-mentioned conditions for the amount of active oxygen species.

Quantification of O ₂ ⁻ can be performed using luminol chemiluminescence. A quartz cell (optical path (length) 1 cm × width 1 cm) placed on a magnetic stirrer in a dark box is charged with 3.5 mL of 0.01 M NaOH aqueous solution, and further 15 mg of a metal compound (photocatalyst) powder (for example, A product obtained by drying a sol (the same applies hereinafter) is added and suspended to obtain a suspension. Next, using the LED (Hamamatsu Photonics, model number “LC-L2”, wavelength: 365 nm) as a light source, the cell containing the suspension is irradiated with ultraviolet light for 10 seconds. After irradiation, 50 μL of a 7 mM luminol solution is added, and chemiluminescence generated by • O ₂ ⁻ is passed through a band-pass filter and then detected with an electron-cooled photomultiplier tube.

H ₂ O ₂ can be quantified using luminol chemiluminescence. In the determination of H ₂ O ₂ , the same operation as in the determination of • O ₂ ⁻ was performed until ultraviolet irradiation, and then the disappearance of • O ₂ ⁻ was waited for 30 minutes, and then 50 μL of a 7 mM luminol solution was added. . After another 10 minutes, 50 μL of 6.2 μM hemoglobin solution is added and chemiluminescence generated by H ₂ O ₂ is detected.

-The quantitative method of OH is as follows. First, a 0.1 mM aqueous solution of coumarin is prepared, and a suspension is obtained by suspending 15 mg of a metal compound (photocatalyst) powder such as TiO ₂ and 35 mL of an aqueous solution of coumarin in a quartz cell having the same dimensions as described above. This suspension is irradiated with LED light having a wavelength of 365 nm and an intensity of 32 mW / cm ² for 120 seconds. Next, in order to separate a metal compound (photocatalyst) powder such as TiO ₂ from the suspension, 0.5 g of KCl is added to the suspension after the irradiation and left in a dark place for 24 hours. Thereafter, the supernatant is taken as a sample, and fluorescence is measured with a Fluorescence spectrophotometer (model number “RF-5300PC”, manufactured by SHIMADZU). At this time, it is confirmed that light scattering during the fluorescence measurement due to the addition of KCl has no effect. Yes.) OH is quantified by comparing the fluorescence intensity of a known concentration of coumarin with the fluorescence intensity of the sample.

  As a method for adjusting the amount of each active oxygen species within the above range, for example, the particle diameter (crystal diameter) of the photocatalyst metal oxide is reduced, or the photocatalyst metal oxide is subjected to surface treatment. And a method of reducing the amount of active oxygen species. However, the method for adjusting the amount of each active oxygen species is not limited to these.

The photocatalytic metal compound, for _{example, TiO 2, ZnO, SrTiO 3} , CdS, GaP, InP, GaAs, BaTiO 3, BaTiO 4, BaTi 4 O 9, K 2 NbO 3, Nb 2 O 5, Fe 2 O 3 _{, Ta 2 O 5, K 3} Ta 3 Si 2 O 3, WO 3, SnO 2, Bi 2 O 3, BiVO 4, NiO, Cu 2 O, SiC, MoS 2, InPb, RuO 2, and CeO ₂ can be mentioned It is done. Among these, metal oxides are preferable from the viewpoint of better photocatalytic activity. In addition, from the viewpoint of improving dispersibility and improving weather resistance, the photocatalyst metal compound particle surface may be used as the photocatalyst metal compound of the present invention in which a metal oxide typified by silica, alumina or the like is deposited. Good.

  As a metal compound for photocatalysts of this embodiment, titanium oxide is preferable from the viewpoint of safety and cost. Titanium oxide has anatase, rutile and brookite crystal structures, any of which can be used.

  The metal compound for photocatalyst according to the present embodiment may have an average (arithmetic average) primary particle diameter in the range of 1 to 400 nm from the viewpoint of improving the performance as a photocatalyst and exhibiting good dispersibility. Preferably, it is in the range of 1 to 100 nm, more preferably in the range of 5 to 50 nm. In addition, when the particle shape of the metal compound for photocatalysts has a major axis and a minor axis such as a rod shape, the arithmetic average of the major axis and minor axis is preferably within the above range. The primary particle diameter of the metal compound for photocatalyst is derived as an arithmetic average of 50 arbitrarily selected particles measured by electron microscope observation.

  The photocatalyst coating film of this embodiment is obtained by forming a film using the photocatalyst composition containing the above-described metal compound for photocatalyst and the binder (B). Here, the “binder” refers to a solid component contained in a binder resin solution or binder resin dispersion substantially using a solvent as a dispersion medium, and the binder resin solution or binder resin dispersion includes a binder resin. Solid content other than may be contained. Examples of the binder resin contained in the binder include polyvinyl alcohol derivatives represented by polyvinyl alcohol, cation-modified polyvinyl alcohol, and silanol-modified polyvinyl alcohol; polyvinyl pyrrolidone, polyacrylamides, starch and starch derivatives; typified by carboxymethyl cellulose and hydroxyethyl cellulose. Cellulose derivatives; casein; gelatin; conventionally known poly (meth) acrylates, polyvinyl acetates, vinyl acetate-acrylic, ethylene vinyl acetates obtained by radical polymerization, anion polymerization, cationic polymerization, etc. , Silicone, fluorine, polybutadiene, styrene butadiene, NBR, polyvinyl chloride, chlorinated polypropylene, polyethylene , Polystyrene-based, vinylidene chloride-based, polystyrene- (meth) acrylate-based, styrene-maleic anhydride-based copolymers; silicone-modified acrylic, fluorine-acrylic, acrylic silicon-based, epoxy-acrylic modified copolymers A polymer; Here, “(meth) acrylate” means methacrylate and its corresponding acrylate. It is preferable that 30 mass%-99.9 mass% is contained with respect to the total mass of a photocatalyst coating film, and it is more preferable that a binder (B) is contained 50 mass%-99 mass%. By including a binder in the range, the photocatalyst coating film is further excellent in film forming property, and the film forming property and the activity of the photocatalyst can be further balanced. The binder (B) may further contain a compound having a functional group that reacts with the functional group of the binder resin. Examples of such compounds include (poly) isocyanate compounds, (poly) epoxy compounds, amino compounds, (poly) carboxy compounds, (poly) hydroxy compounds, glycol compounds, silanol compounds, silyl compounds, alkoxy compounds, (meta ) Acrylates.

  The binder (B) in the photocatalyst coating film of the present embodiment is formed from polymer particles (B1) and metal oxide particles that do not exhibit photocatalytic activity, that is, metal oxide particles (B2) other than the metal compound for photocatalyst. It is preferred that

  As the polymer constituting the polymer particles (B1) according to the present embodiment, for example, conventionally known poly (meth) acrylate-based, polyvinyl acetate-based obtained by radical polymerization, anionic polymerization, cationic polymerization, etc. in a medium, Vinyl acetate-acrylic, ethylene vinyl acetate, silicone, fluorine, polybutadiene, styrene butadiene, NBR, polyvinyl chloride, chlorinated polypropylene, polyethylene, polystyrene, vinylidene chloride, polystyrene- ( Mono- or copolymer represented by (meth) acrylate, styrene-maleic anhydride, modified copolymer represented by silicone-modified acrylic, fluorine-acrylic, acrylic silicon, and epoxy-acrylic. Can be mentioned. These are used singly or in combination of two or more.

  As the polymer particles according to the present embodiment, polymer emulsion particles obtained by a method such as emulsion polymerization can be used. Preferable examples thereof include acrylic emulsion particles and acrylic silicon emulsion particles obtained by a method such as emulsion polymerization. In particular, when polymer emulsion particles having a particle diameter of 10 to 800 nm obtained by polymerizing a hydrolyzable silicon compound and a vinyl monomer in the presence of water and an emulsifier are used, the resulting photocatalytic coating film is weather resistant. Since it is excellent in property, it is preferable.

Examples of the hydrolyzable silicon compound used for producing the polymer emulsion particles of this embodiment include compounds represented by the following general formula (1), condensation products thereof, and silane coupling agents. .
SiW _x R _y (1)
Wherein W is an alkoxy group having 1 to 20 carbon atoms, a hydroxyl group, an acetoxy group having 1 to 20 carbon atoms, a halogen atom, a hydrogen atom, an oxime group having 1 to 20 carbon atoms, an enoxy group, an aminoxy group, and an amide group. R represents at least one group or atom selected from: R is a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, and unsubstituted. Or at least one group selected from an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms substituted with a halogen atom, x is 1 or more. (It is an integer of 4 or less, and y is an integer of 0 to 3. Further, x + y = 4.)

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

  Specific examples of the silicon alkoxide (the compound represented by the general formula (1) and the condensation product thereof in which W is an alkoxy group) and the silane coupling agent include tetramethoxysilane, tetraethoxysilane, tetra -Tetraalkoxysilanes such as n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane; methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane N-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, n- Ptyltrimethoxysilane, n-octyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-chloro Propyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-amino Propyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2-hydroxyethyltriethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriet Sisilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxy Silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxy Silane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloyloxypropyltri-n-propoxysilane, 3- ( Trialkoxysilanes such as (meth) acryloyloxypropyltriisopropoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, Di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane, di-n-butyldimethoxysilane, di-n-butyldiethoxysilane, di-n-pentyldimethoxysilane Di-n-pentyldiethoxysilane, di-n-hexyldimethoxysilane, di-n-hexyldiethoxysilane, di-n-heptyldimethoxysilane, di-n-heptyldiethoxysilane Di-n-octyldimethoxysilane, di-n-octyldiethoxysilane, di-n-cyclohexyldimethoxysilane, di-n-cyclohexyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, 3- (meth) acryloyloxy Examples include dialkoxysilanes such as propylmethyldimethoxysilane; monoalkoxysilanes such as trimethylmethoxysilane and trimethylethoxysilane. These silicon alkoxides and silane coupling agents can be used alone or in combination of two or more.

  When the silicon alkoxide or silane coupling agent is used as a condensation product, the condensation product preferably has a polystyrene equivalent weight average molecular weight of 200 to 5,000, more preferably 300 to 1,000. Among the silicon alkoxides, silicon alkoxides having a phenyl group, for example, phenyltrimethoxysilane, phenyltriethoxysilane, and diphenyldimethoxysilane are very preferable because they have excellent polymerization stability in the presence of water and an emulsifier.

  Among hydrolyzable silicon compounds that can be used in this embodiment, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloyloxypropyl Methyldimethoxysilane, 3- (meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, 2-trimethoxy Silane coupling agents having a vinyl polymerizable group such as silylethyl vinyl ether and silane coupling agents having a thiol group such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane are It is possible to generate a chemical bond by copolymerization or chain transfer reaction with. For this reason, when a silane coupling agent having a vinyl polymerizable group or a thiol group is used alone or mixed or compounded with the above-described silicon alkoxide, silane coupling agent, and their condensation products, The polymerized product of the hydrolyzable silicon compound and the polymerized product of the vinyl monomer constituting the polymer emulsion particles in the form can be combined by chemical bonding. A photocatalyst coating film containing such polymer emulsion particles is very preferable because it is excellent in weather resistance, strength and the like.

  Examples of the vinyl monomer include acrylic acid ester, methacrylic acid ester, aromatic vinyl compound, vinyl cyanide, carboxyl group-containing vinyl monomer, hydroxyl group-containing vinyl monomer, and glycidyl group-containing vinyl. Examples thereof include a monomer, a carbonyl group-containing vinyl monomer, a vinyl monomer having a secondary and / or tertiary amide group, and an anionic vinyl monomer. Examples of the (meth) acrylic acid ester include (meth) acrylic acid alkyl ester having 1 to 50 carbon atoms in the alkyl portion, and (poly) oxyethylene di (meth) acrylate having 1 to 100 ethylene oxide groups. Is mentioned. Specific examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and methyl (meth) acrylate. Examples include cyclohexyl, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, and dodecyl (meth) acrylate. Specific examples of (poly) oxyethylene di (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, diethylene glycol methoxy (meth) acrylate, tetraethylene glycol di (meth) acrylate Is mentioned.

  In the present specification, (meth) acrylic is a simple description of methacrylic or acrylic.

  Examples of the carboxyl group-containing vinyl monomer include dibasic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, or itaconic acid, maleic acid, and fumaric acid. A half ester is mentioned. By using a carboxylic acid group-containing vinyl monomer, a carboxyl group can be introduced into the polymer emulsion particles, improving the stability as an emulsion, and providing resistance to external dispersion destruction. Is possible. At this time, part or all of the introduced carboxyl group can be neutralized with an amine such as ammonia, triethylamine or dimethylethanolamine, or a base such as NaOH or KOH.

  It is preferable from the surface of water resistance that the usage-amount of a carboxyl group-containing vinyl monomer is 0-50 mass% in all the vinyl monomers as 1 type, or 2 or more types of mixtures.

  Examples of the hydroxyl group-containing vinyl monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth). Hydroxyalkyl esters of (meth) acrylic acid such as acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl monobutyl fuma (Poly) oxyethylene mono (meth) acrylate having 1 to 100 acrylates, allyl alcohol or ethylene oxide groups, (poly) oxypropylene mono (meth) acrylate having 1 to 100 propylene oxide groups, , "Plaxel FM, F Monomer "(manufactured by Daicel Chemical Industries, Ltd., trade name of caprolactone addition monomer) and other alpha, hydroxyalkyl esters of β- ethylenically unsaturated carboxylic acid. Specific examples of the (poly) oxyethylene mono (meth) acrylate include ethylene glycol (meth) acrylate, ethylene glycol methoxy (meth) acrylate, diethylene glycol (meth) acrylate, diethylene glycol methoxy (meth) acrylate, ( Examples thereof include tetraethylene glycol (meth) acrylate and tetraethylene glycol methoxy (meth) acrylate. Specific examples of (poly) oxypropylene mono (meth) acrylate include propylene glycol (meth) acrylate, propylene glycol methoxy (meth) acrylate, dipropylene glycol (meth) acrylate, and methoxy (meth) acrylic acid. Examples include dipropylene glycol, (meth) acrylic acid tetrapropylene glycol, and methoxy (meth) acrylic acid tetrapropylene glycol.

  The use amount of the hydroxyl group-containing vinyl monomer described above is preferably 0 to 80% by mass, more preferably 0.1 to 50% by mass in all vinyl monomers as one or a mixture of two or more. .

  Examples of the glycidyl group-containing vinyl monomer include glycidyl (meth) acrylate, allyl glycidyl ether, and allyl dimethyl glycidyl ether. The amount of the glycidyl group-containing vinyl monomer used is preferably 0 to 50% by mass in all vinyl monomers.

  When a hydroxyl group-containing vinyl monomer, a glycidyl group-containing vinyl monomer, or a carbonyl group-containing vinyl monomer is used, the polymer emulsion particles are reactive and crosslinked by hydrazine derivatives, carboxylic acid derivatives, isocyanate derivatives, etc. Thus, it is possible to form a coating film having excellent solvent resistance.

  Examples of the vinyl monomer having a secondary and / or tertiary amide group include N-alkyl or N-alkylene-substituted (meth) acrylamide. Specifically, for example, N-methyl Acrylamide, N-methyl methacrylamide, N-ethyl acrylamide, N, N-dimethyl acrylamide, N, N-dimethyl methacrylamide, N, N-diethyl acrylamide, N-ethyl methacrylamide, N-methyl-N-ethyl acrylamide, N-methyl-N-ethylmethacrylamide, N-isopropylacrylamide, Nn-propylacrylamide, N-isopropylmethacrylamide, Nn-propylmethacrylamide, N-methyl-Nn-propylacrylamide, N-methyl -N-Isopropyl Aqua Luamide, N-acryloylpyrrolidine, N-methacryloylpyrrolidine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylhexahydroazepine, N-acryloylmorpholine, N-methacryloylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, N , N′-methylenebisacrylamide, N, N′-methylenebismethacrylamide, N-vinylacetamide, diacetone acrylamide, diacetone methacrylamide, N-methylol acrylamide, and N-methylol methacrylamide.

  Specific examples of vinyl monomers other than those described above include, for example, olefins such as (meth) acrylamide, ethylene, propylene, and isobutylene, dienes such as butadiene, vinyl chloride, vinylidene chloride, tetrafluoroethylene, and chlorotri Haloolefins such as fluoroethylene, vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl benzoate, vinyl pt-butylbenzoate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl versatate, lauric acid Carboxylic acid vinyl esters such as vinyl, isopropenyl acetate, isopropenyl propionate, etc., vinyl ethers such as ethyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether, styrene, vinyl Aromatic vinyl compounds such as toluene, allyl esters such as allyl acetate and allyl benzoate, allyl ethers such as allyl ethyl ether and allyl phenyl ether, and 4- (meth) acryloyloxy-2,2,6,6 -Tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6, -pentamethylpiperidine, perfluoromethyl (meth) acrylate, perfluoropropyl (meth) acrylate, perfluoropropyromethyl ( Examples thereof include (meth) acrylate, vinylpyrrolidone, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, and combinations thereof.

  In this embodiment, a chain transfer agent may be used for the purpose of controlling the molecular weight of the polymerization product of the vinyl monomer.

  Examples of such chain transfer agents include alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan; aromatic mercaptans such as benzyl mercaptan and dodecyl benzyl mercaptan; thiocarboxylic acids such as thiomalic acid. Examples thereof include allyl compounds such as acids or salts thereof or alkyl esters thereof, or polythiols, diisopropylxanthogen disulfide, di (methylenetrimethylolpropane) xanthogen disulfide and thioglycol, and α-methylstyrene dimer. .

  These chain transfer agents can be used in the range of preferably 0.001 to 30% by mass, more preferably 0.05 to 10% by mass with respect to the total vinyl monomers.

  The mass ratio of the vinyl monomer to the hydrolyzable silicon compound is 5/95 to 95/5, preferably 10/90 to 90/10.

  In the present embodiment, it is particularly preferable from the viewpoint of weather resistance to use a silane coupling agent having a vinyl polymerizable group as the hydrolyzable silicon compound, and its blending amount is 0.01 to 100 parts by mass of the polymer emulsion particles. It is preferable from the viewpoint of polymerization stability that it is not less than 20 parts by mass. More preferably, they are 0.1 mass part or more and 10 mass parts or less.

  Moreover, it is preferable from the surface of superposition | polymerization stability that the compounding quantity of the silane coupling agent which has a vinyl polymerizable group is 0.1 to 100 mass parts with respect to 100 mass parts of vinyl monomers.

  In this embodiment, it is possible to use a cyclic siloxane oligomer in combination with the hydrolyzable silicon compound described above. By using the cyclic siloxane oligomer in combination, a photocatalytic coating film excellent in flexibility and the like can be formed.

As said cyclic siloxane oligomer, the compound represented by following General formula (2) can be illustrated.
(R ' ₂ SiO) _m (2)
(In the formula, R ′ is a hydrogen atom, a linear or branched alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, and an unsubstituted or substituted carbon atom having 1 to 30 carbon atoms. It represents at least one selected from an alkyl group having 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms substituted with a halogen atom, m is an integer, and 2 ≦ m ≦ 20 is there.)

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

  Moreover, in this embodiment, titanium alkoxide, zirconium alkoxide, and their condensation products, or those chelating products can also be used together with the hydrolyzable silicon compound mentioned above. By using these compounds in combination, a photocatalytic coating film excellent in water resistance, hardness and the like can be formed.

  Specific examples of the titanium alkoxide include, for example, tetramethoxy titanium, tetraethoxy titanium, tetra-i-propoxy titanium, tetra-n-propoxy titanium, tetra-n-butoxy titanium, tetra-sec-butoxy titanium, tetra-tert. -Butoxy titanium is mentioned.

  When the titanium alkoxide is used as a condensation product, the weight average molecular weight in terms of polystyrene of the condensation product is preferably 200 to 5,000, more preferably 300 to 1,000.

  Specific examples of the zirconium alkoxide include tetramethoxy zirconium, tetraethoxy zirconium, tetra-i-propoxy zirconium, tetra-n-propoxy zirconium, tetra-n-butoxy zirconium, tetra-sec-butoxy zirconium, tetra-tert. -Butoxyzirconium is mentioned.

  When the zirconium alkoxide is used as a condensation product, the weight average molecular weight in terms of polystyrene of the condensation product is preferably 200 to 5,000, more preferably 300 to 1,000.

  Preferred chelating agents for coordination with free metal compounds (eg, titanium alkoxide and zirconium alkoxide) to form a chelate include alkanolamines such as diethanolamine and triethanolamine; ethylene glycol, diethylene glycol, Examples thereof include glycols such as propylene glycol; acetylacetone; ethyl acetoacetate and the like having a molecular weight of 10,000 or less. By using these chelating agents, the polymerization rate of the hydrolyzable silicon compound can be controlled, and this is very preferable because the polymerization stability in the presence of water and an emulsifier is excellent. In this case, the chelating agent is preferably used in a ratio of 0.1 mol to 2 mol per mol of the metal atom of the free metal compound that coordinates it.

  In this embodiment, as an emulsifier that can be used for the synthesis of polymer emulsion particles, for example, alkylbenzene sulfonic acid, alkyl sulfonic acid, alkyl sulfosuccinic acid, polyoxyethylene alkylsulfuric acid, polyoxyethylene alkylaryl sulfuric acid, polyoxyethylene Acidic emulsifiers such as distyrylphenyl ether sulfonic acid, alkali metal (Li, Na, K, etc.) salts of acidic emulsifiers, ammonium salts of acidic emulsifiers, anionic surfactants such as fatty acid soaps, for example, alkyltrimethylammonium bromide, Quaternary ammonium salts such as alkylpyridinium bromides, imidazolinium laurates, pyridinium salts, imidazolinium salt type cationic surfactants, polyoxyethylene alkylaryl ethers, polyoxyethylenes Nsorubitan fatty acid esters may be exemplified a reactive emulsifier having a polyoxyethylene polyoxypropylene block copolymer, a nonionic surfactant or a radically polymerizable such as polyoxyethylene distyryl phenyl ether double bond.

  Among these emulsifiers, when a reactive emulsifier having a radical polymerizable double bond is selected, the water dispersion stability of the polymer emulsion particles becomes very good, and the photocatalyst coating containing the polymer emulsion particles is performed. The film is very preferable because it is excellent in weather resistance, water resistance and the like.

  Examples of the reactive emulsifier having a radical polymerizable double bond include, for example, a vinyl monomer having a sulfonic acid group or a sulfonate group, a vinyl monomer having a sulfate group, an alkali metal salt thereof, an ammonium salt, Examples thereof include vinyl monomers having a nonionic group such as polyoxyethylene, and vinyl monomers having a quaternary ammonium salt.

  As a specific example of the reactive emulsifier, taking a vinyl monomer salt having a sulfonic acid group or a sulfonate group as an example, it has a radical polymerizable double bond, and is an ammonium salt or sodium salt of a sulfonic acid group. Or an alkyl group having 1 to 20 carbon atoms, an alkyl ether group having 2 to 4 carbon atoms, a polyalkyl ether group having 2 to 4 carbon atoms, a 6 or 10 carbon atom, partially substituted with a group that is a potassium salt Examples thereof include a vinyl sulfonate compound having a substituent selected from the group consisting of an aryl group and a succinic acid group, or having a vinyl group to which a group of an ammonium salt, sodium salt or potassium salt of a sulfonic acid group is bonded. It is done. As the vinyl monomer having a sulfate ester group, for example, carbon having a radical polymerizable double bond and partially substituted by a group that is an ammonium salt, sodium salt or potassium salt of a sulfate ester group. Examples include compounds having a substituent selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkyl ether group having 2 to 4 carbon atoms, a polyalkyl ether group having 2 to 4 carbon atoms, and an aryl group having 6 or 10 carbon atoms. It is done.

  Specific examples of the compound having a succinic acid group partially substituted with a group which is an ammonium salt, sodium salt or potassium salt of the sulfonic acid group include allylsulfosuccinate. Specific examples thereof include, for example, Eleminol JS-2 (trade name) (manufactured by Sanyo Kasei Co., Ltd.), Latemul S-120, S-180A or S-180 (trade name) (manufactured by Kao Corporation). be able to.

  Further, a compound having an alkyl ether group having 2 to 4 carbon atoms or a polyalkyl ether group having 2 to 4 carbon atoms, which is partially substituted by a group which is an ammonium salt, sodium salt or potassium salt of the sulfonic acid group. As specific examples, for example, Aqualon HS-10 or KH-1025 (trade name) (Daiichi Kogyo Seiyaku Co., Ltd.), Adekaria Soap SE-1025N or SR-1025 (trade name) (Asahi Denka Kogyo Co., Ltd.) ).

  Other specific examples of the compound having an aryl group partially substituted with a sulfonate group include ammonium salt, sodium salt and potassium salt of p-styrenesulfonic acid.

  Examples of the vinyl sulfonate compound having a vinyl group to which the ammonium salt, sodium salt or potassium salt of the sulfonic acid group is bonded include, for example, alkyl sulfonic acid (meth) acrylates such as 2-sulfoethyl acrylate and methylpropane sulfone. Examples thereof include ammonium salts such as acid (meth) acrylamide and allyl sulfonic acid, sodium salts, and potassium salts.

  Examples of the compound having an alkyl ether group having 2 to 4 carbon atoms or a polyalkyl ether group having 2 to 4 carbon atoms partially substituted with the ammonium salt, sodium salt or potassium salt of the sulfate ester group include, for example, Examples thereof include compounds having an alkyl ether group partially substituted with a sulfonate group.

  In addition, specific examples of vinyl monomers having a nonionic group include α- [1-[(allyloxy) methyl] -2- (nonylphenoxy) ethyl] -ω-hydroxypolyoxyethylene (trade name: ADEKA rear soap). NE-20, NE-30, NE-40, etc., manufactured by Asahi Denka Kogyo Co., Ltd.), polyoxyethylene alkylpropenyl phenyl ether (trade names: Aqualon RN-10, RN-20, RN-30, RN-50, etc.) , Daiichi Pharmaceutical Industry Co., Ltd.).

  As the usage-amount of the said emulsifier, the inside of the range used as 10 mass parts or less with respect to 100 mass parts of polymer emulsion particle | grains is suitable, Especially, it exists within the range used as 0.001-5 mass parts.

  In addition to the above emulsifiers, a dispersion stabilizer can also be used for the purpose of improving the water dispersion stability of the polymer emulsion particles. Examples of the dispersion stabilizer include various water-soluble oligomers selected from the group consisting of polycarboxylic acids and sulfonates, polyvinyl alcohol, hydroxyethyl cellulose, starch, maleated polybutadiene, maleated alkyd resin, polyacrylic acid (salt ), Synthetic or natural water-soluble or water-dispersible water-soluble polymer substances such as polyacrylamide, water-soluble or water-dispersible acrylic resin, etc., and one or a mixture of two or more of these are used. be able to.

  When these dispersion stabilizers are used, the amount used is suitably within 10 parts by mass or less with respect to 100 parts by mass of the polymer emulsion particles, and in particular, 0.001 to 5 parts by mass. Within the range is preferable.

  In the present embodiment, the polymerization of the hydrolyzable silicon compound and the vinyl monomer is preferably performed in the presence of a polymerization catalyst.

  Here, as a polymerization catalyst for the hydrolyzable silicon compound, hydrogen halides such as hydrochloric acid and hydrofluoric acid, carboxylic acids such as acetic acid, trichloroacetic acid, trifluoroacetic acid and lactic acid, sulfones such as sulfuric acid and p-toluenesulfonic acid, etc. Acids, alkylbenzenesulfonic acid, alkylsulfonic acid, alkylsulfosuccinic acid, polyoxyethylene alkylsulfuric acid, polyoxyethylene alkylarylsulfuric acid, polyoxyethylene distyrylphenyl ether sulfonic acid and other acidic emulsifiers, acidic or weakly acidic inorganic salts, Acidic compounds such as phthalic acid, phosphoric acid, nitric acid; sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, tetramethylammonium chloride, tetramethylammonium hydroxide, tributylamine, diazabicycloundecene, ethyl Basic compounds such as diamine, diethylenetriamine, ethanolamine, γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl) -aminopropyltrimethoxysilane; tin compounds such as dibutyltin octylate and dibutyltin dilaurate Can be mentioned.

  Among these, as a polymerization catalyst for a hydrolyzable silicon compound, not only a polymerization catalyst but also an acidic emulsifier having an action as an emulsifier, particularly an alkylbenzene sulfonic acid having 5 to 30 carbon atoms (such as dodecylbenzene sulfonic acid). Highly preferred.

  On the other hand, as the polymerization catalyst for the vinyl monomer, a radical polymerization catalyst that causes radical polymerization by heat or a reducing substance to cause addition polymerization of the vinyl monomer is preferable, and is a water-soluble or oil-soluble persulfate. Peroxides, azobis compounds and the like are used. Examples include potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, 2,2-azobisisobutyronitrile, 2,2-azobis. (2-diaminopropane) hydrochloride and 2,2-azobis (2,4-dimethylvaleronitrile) are mentioned, and the blending amount is 0.001 to 5 mass with respect to 100 mass parts of the total vinyl monomer. Part is preferred. When acceleration of the polymerization rate and low temperature polymerization at 70 ° C. or lower are desired, it is advantageous to use a reducing agent such as sodium bisulfite, ferrous chloride, ascorbate, or longalite in combination with the radical polymerization catalyst. It is. Polymerization of the hydrolyzable silicon compound and the vinyl monomer can be carried out separately, but it is preferable because the organic / inorganic composite can be achieved by carrying out the polymerization simultaneously.

  In the present embodiment, it is preferable that the particle diameter of the polymer emulsion particles is 10 to 800 nm. A photocatalyst coating film adjusted to such a particle diameter range and combined with colloidal silica having a particle diameter of 100 nm or less is particularly excellent in weather resistance, antifouling property and the like, and is preferable. The particle diameter of the polymer emulsion particles is more preferably 30 to 300 nm in terms of number average particle diameter because the transparency of the resulting coating film is improved. The particle diameter of the polymer emulsion particles is measured according to the method described in the following examples.

  As a method for obtaining polymer emulsion particles having such a particle size, so-called emulsion polymerization in which an emulsifier polymerizes a hydrolyzable silicon compound and a vinyl monomer in the presence of a sufficient amount of water to form micelles. This is the most suitable method.

  As a method (method) of the emulsion polymerization, for example, the hydrolyzable silicon compound and the vinyl monomer are dropped into the reaction vessel as they are or in an emulsified state, all at once or in a divided manner, or continuously. The polymerization may be performed at a reaction temperature of about 30 to 150 ° C. in the presence of a catalyst, preferably from atmospheric pressure to a pressure of 10 MPa if necessary. In some cases, the polymerization may be carried out at a higher pressure or lower temperature. The ratio between the total amount of the hydrolyzable silicon compound and all vinyl monomers and water is preferably set so that the final solid content is in the range of 0.1 to 70% by mass, preferably 1 to 55% by mass. Further, in order to grow or control the particle diameter in carrying out emulsion polymerization, a seed polymerization method in which emulsion particles are preliminarily present in an aqueous phase may be used. The polymerization reaction may be allowed to proceed in the range of pH in the system of preferably 1.0 to 10.0, more preferably 1.0 to 6.0. The pH can be adjusted using a pH buffer such as disodium phosphate, borax, sodium hydrogen carbonate, or ammonia.

  In this embodiment, when the polymer emulsion particles have a core / shell structure formed of two or more layers, the photocatalytic coating film containing the polymer emulsion particles has mechanical properties (such as a balance between strength and flexibility). ) And is preferable.

  Multi-stage emulsion polymerization is very useful as a method for producing the polymer emulsion particles having the core / shell structure.

  Here, the multistage emulsion polymerization means that two or more kinds of hydrolyzable silicon compounds and vinyl monomers having different compositions are prepared and polymerized in separate stages.

  Hereinafter, the synthesis of polymer emulsion particles by multi-stage emulsion polymerization according to this embodiment will be described by taking the synthesis of polymer emulsion particles by 2-stage emulsion polymerization as the simplest and most useful among multi-stage emulsion polymerizations as an example.

  In this embodiment, as the synthesis of polymer emulsion particles by two-stage emulsion polymerization, for example, in the presence of seed particles obtained by polymerizing a vinyl monomer and / or a hydrolyzable silicon compound in the presence of water and an emulsifier. A method of polymerizing a hydrolyzable silicon compound and / or a vinyl monomer can be exemplified.

  The synthesis of the polymer emulsion particles by the above-mentioned two-stage emulsion polymerization consists of the first stage polymerization in which the first series (vinyl monomer and / or hydrolyzable metal compound) is supplied and emulsion polymerization, and the first stage. The second series (vinyl monomer and / or hydrolyzable metal compound) is supplied, and this is carried out by a two-stage polymerization process comprising a second stage polymerization in which emulsion polymerization is carried out in an aqueous medium. At this time, the mass ratio of the solid content mass (M1) in the first series to the solid content mass (M2) in the second series is preferably (M1) / (M2) = 9/1 to 1/9, More preferably, it is 8/2 to 2/8.

  In the present embodiment, the polymer having a preferable core / shell structure is characterized in that the particle size of the seed particles obtained by the first stage polymerization changes greatly in the particle size distribution (volume average particle size / number average particle size). Without (preferably in a monodispersed state), it can be increased (increase in particle size) by the second stage polymerization.

  The core / shell structure can be confirmed by, for example, morphological observation with a transmission electron microscope, analysis by viscoelasticity measurement, or the like.

  In the present embodiment, when multi-stage emulsion polymerization of three or more stages is performed, the number of series to be polymerized may be increased with reference to the synthesis example of the polymer emulsion particles by the two-stage polymerization described above.

  The blending amount of the polymer emulsion particles is preferably more than 0 to 70% as mass% with respect to the entire photocatalyst coating film. More preferably, it is 1-60%, More preferably, it is 5-50%.

  Examples of the metal oxide particles (B2) other than the metal compound for photocatalyst according to the present embodiment include silicon dioxide (silica) particles, aluminum oxide (alumina) particles, calcium silicate particles, magnesium oxide particles, antimony oxide particles, Examples thereof include zirconium oxide particles and composite oxide particles thereof. These are used singly or in combination of two or more. Among them, from the viewpoint of increasing the surface hydroxyl groups, increasing the surface area of the metal oxide particles, and strengthening the bond between the metal oxide particles or the bond between the metal oxide and the polymer particles, the silicon dioxide particles, Aluminum oxide particles, antimony oxide particles and composite oxide particles thereof are preferable, and colloidal silica particles which are a dispersion in a solvent of silica having silicon dioxide as a basic unit are more preferable.

  Colloidal silica can be prepared and used by a sol-gel method, and a commercially available product can also be used. For preparation by the sol-gel method, Werner Stober et al; Colloid and Interface Sci. , 26, 62-69 (1968), Rickey D .; Badley et al; Lang muir 6, 792-801 (1990), Color Material Association Journal, 61 [9] 488-493 (1988), and the like. Examples of the acidic colloidal silica using water as a dispersion medium include, as commercial products, Snowtex (trademark) -O manufactured by Nissan Chemical Industries, Ltd., Snowtex-OS, Adelite (trademark) AT manufactured by Asahi Denka Kogyo Co., Ltd. -20Q, Clariant Japan K.K. clebosol (trademark) 20H12, clebosol 30CAL25, etc. can be used.

  Examples of basic colloidal silica include silica stabilized by addition of alkali metal ions, ammonium ions, and amines, such as SNOWTEX-20, SNOWTEX-30, SNOWTEX-C, manufactured by Nissan Chemical Industries, Ltd. SNOWTEX-C30, SNOWTEX-CM40, SNOWTEX-N, SNOWTEX-N30, SNOWTEX-K, SNOWTEX-XL, SNOWTEX-YL, SNOWTEX-ZL, SNOWTEX PS-M, SNOWTEX PS- L, etc .; Adelite AT-20, Adelite AT-30, Adelite AT-20N, Adelite AT-30N, Adelite AT-20A, Adelite AT-30A, Adelite AT-40, Adelite AT-50, etc. ; Clariant Japan Co., Ltd. Ltd. Kurebozoru 30R9, Kurebozoru 30R50, such Kurebozoru 50R50, DuPont Ludox (TM) HS-40, Ludox HS-30, Ludox LS, mention may be made of Ludox SM-30.

  Further, as colloidal silica using a water-soluble solvent as a dispersion medium, for example, MA-ST-M (methanol dispersion type having a particle diameter of 20 to 25 nm), IPA-ST (particle diameter of 10) manufactured by Nissan Chemical Industries, Ltd. ˜15 nm isopropyl alcohol dispersion type), EG-ST (ethylene glycol dispersion type with particle diameter of 10 to 15 nm), EG-ST-ZL (ethylene glycol dispersion type with particle diameter of 70 to 100 nm), NPC-ST (particles) And ethylene glycol monopropyl ether dispersion type) having a diameter of 10 to 15 nm.

  These colloidal silicas may be used alone or in combination of two or more. Colloidal silica may contain alumina, sodium aluminate or the like as a minor component. Colloidal silica may contain an inorganic base (such as sodium hydroxide, potassium hydroxide, lithium hydroxide, or ammonia) or an organic base (such as tetramethylammonium) as a stabilizer. The average particle diameter of the metal oxide particles (B2) is preferably 100 nm or less. More preferably, it is 50 nm or less, More preferably, it is 20 nm. Use of metal oxide particles (B2) having an average particle size of 10 nm or less is most preferable because the resulting photocatalyst coating film has very high transparency. The particle diameter (number average particle diameter) of the metal oxide particles (B2) is measured according to the method described in the following examples.

  Although the film thickness of the photocatalyst coating film of this embodiment is not specifically limited, It is preferable that it is 0.05-100 micrometers, It is more preferable that it is 0.1-10 micrometers, It is 1.0-2.5 micrometers. Further preferred. When the thickness is 100 μm or less, good transparency can be secured, and when the thickness is 0.05 μm or more, functions such as antifouling properties and photocatalytic activity can be more effectively expressed.

  The photocatalyst coating film of the present embodiment may contain a dispersion stabilizer from the viewpoint of dispersion stability of each particle contained therein. Examples of the dispersion stabilizer include various water-soluble oligomers selected from the group consisting of polycarboxylic acids and sulfonates, polyvinyl alcohol, hydroxyethyl cellulose, starch, maleated polybutadiene, maleated alkyd resin, polyacrylic acid (salt ), Various synthetic or natural polymer materials represented by polyacrylamide and acrylic resins. A dispersion stabilizer is used individually by 1 type or in mixture of 2 or more types.

  In addition, the photocatalyst coating film of the present embodiment has components added to and blended with ordinary paints and molding resins, for example, a solvent, a thickener, a leveling agent, and a thixotropic agent, depending on the application and method of use. , Antifoaming agent, Freezing stabilizer, Matting agent, Crosslinking reaction catalyst, Pigment, Curing catalyst, Crosslinking agent, Filler, Anti-skinning agent, Dispersant, Wetting agent, Light stabilizer, Antioxidant, UV absorber , Rheology control agent, antifoaming agent, film forming aid, rust preventive agent, dye, plasticizer, lubricant, reducing agent, preservative, antifungal agent, deodorant, anti-yellowing agent, antistatic agent or A charge adjusting agent or the like may be contained.

  The photocatalyst coating film of this embodiment is obtained by applying the photocatalyst composition to the surface of a substrate or a coating covering the substrate and drying it. Examples of the base material on which the photocatalyst composition is applied include organic substrates represented by synthetic resins, natural resins, fibers, inorganic substrates represented by metals, ceramics, glass, stone, cement, concrete, and combinations thereof. Is mentioned.

  Examples of the synthetic resin include thermoplastic resins and curable resins (thermosetting resins, photocurable resins, moisture curable resins, and the like). Specific examples include silicone resin, acrylic resin, methacrylic resin, fluorine resin, alkyd resin, aminoalkyd resin, vinyl resin, polyester resin, styrene-butadiene resin, polyolefin resin, polystyrene resin, polyketone resin, polyamide resin, polycarbonate. Resin, polyacetal resin, polyether ether ketone resin, polyphenylene oxide resin, polysulfone resin, polyphenylene sulfone resin polyether resin, polyvinyl chloride resin, polyvinylidene chloride resin, urea resin, phenol resin, melamine resin, epoxy resin, urethane resin, A silicone-acrylic resin is mentioned. Examples of the natural resin include cellulose resins, isoprene resins typified by natural rubber, and protein resins typified by casein.

  When the substrate is a resin plate or fiber, the surface thereof may be subjected to a surface treatment such as a corona discharge treatment, a flame treatment, or a plasma treatment, but these surface treatments are not essential.

  The photocatalyst coating film of the present embodiment can be applied by any method according to the use of the photocatalyst composition. Examples of the application method include spray spraying, flow coating, roll coating, brush coating, dip coating, spin coating, screen printing, casting, gravure printing, and flexographic printing.

  The photocatalyst coating film of this embodiment is obtained by applying a photocatalyst composition and then drying to remove volatile components. At this time, for example, after drying at a low temperature of 20 ° C. to 80 ° C., heat treatment at 20 ° C. to 500 ° C., more preferably 40 ° C. to 250 ° C. may be performed as desired, and ultraviolet irradiation or the like is performed. Also good.

  In this embodiment, a photocatalyst-coated product includes a substrate and the photocatalyst coating film formed on the substrate. The photocatalyst-coated product may be the same as a known aspect except that the photocatalyst coating film of this embodiment is provided. Specific examples of the photocatalyst-coated product of the present embodiment include, for example, building materials, building exteriors, building interiors, window frames, window glass, structural members, building facilities such as houses, vehicle illumination lamp covers, window glass, mechanical devices, Exterior of goods, dustproof cover and painting, display equipment, its covers, traffic signs, various display devices, display objects such as advertising towers, sound insulation walls for roads and railways, bridges, exterior and painting of guardrails, tunnel interior and painting , Electronic parts used outside such as insulators, solar battery covers, solar water heater heat collection covers, etc., and exterior parts of electrical equipment, especially exteriors such as transparent members, greenhouses and greenhouses. This photocatalyst-coated product may be obtained by applying the photocatalyst composition containing the photocatalyst particles (A) and the binder (B) to the surface of the substrate and drying to form a photocatalyst coating film on the substrate. The manufacturing method is not limited to this. For example, the substrate and the photocatalyst coating film may be molded at the same time, and more specifically, may be integrally molded.

  In addition, after the photocatalyst coating film of the present embodiment is formed on a substrate, the photocatalyst coating film is adhered to another substrate by adhesion, fusion, or the like in a state where the photocatalyst coating film is peeled off or adhered to the substrate. You may let them.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to the said this embodiment. The present invention can be variously modified without departing from the gist thereof.

  The following examples, reference examples and comparative examples will specifically explain the present invention, but these do not limit the scope of the present invention. Various physical properties were measured by the following methods.

1. · O ₂ ^- using quantitative luminol chemiluminescence was performed in the following procedure. Into a quartz cell (light path (length) 1 cm x width 1 cm) placed on a magnetic stirrer in a dark box, 3.5 mL of 0.01 M NaOH aqueous solution is added, and then 15 mg of metal compound (photocatalyst) powder is added. Suspension was obtained. Next, using the LED (Hamamatsu Photonics (Hamamatsu Photonics), model number “LC-L2” wavelength: 365 nm) as a light source, the cell containing the suspension was irradiated with ultraviolet light for 10 seconds. 50 μL of 7 mM luminol solution was added to the suspension after irradiation, and chemiluminescence generated by • O ₂ ⁻ was passed through a bandpass filter, and then detected with an electron-cooled photomultiplier tube [• O ₂ ⁻ ] Was derived.

2. Quantitative determination of H ₂ O ₂ The suspension obtained in the same manner as in 1 above was irradiated with ultraviolet light in the same manner as above, and after waiting for disappearance of O ₂ ⁻ for 30 minutes, a 7 mM luminol solution was then added. Was added to the suspension. Ten minutes later, 50 μL of a 6.2 μM hemoglobin solution was added to the suspension, and the resulting chemiluminescence was detected to derive the value of [H ₂ O ₂ ].

3. -Determination of OH A 0.1 mM coumarin aqueous solution was prepared, and 15 mg of a metal compound (photocatalyst) powder and 35 mL of a coumarin aqueous solution were suspended in a quartz cell having the same dimensions as described above to obtain a suspension. This suspension was irradiated with LED light having a wavelength of 365 nm and an intensity of 32 mW / cm ² for 120 seconds. Next, in order to separate the metal compound (photocatalyst) powder from the suspension, 0.5 g of KCl was added to the suspension after the irradiation, and the mixture was allowed to stand in the dark for 24 hours. Thereafter, the supernatant was taken as a sample, and fluorescence was measured with a Fluorescence spectrophotometer (model number “RF-5300PC”, manufactured by SHIMADZU). At this time, light scattering at the time of fluorescence measurement by addition of KCl did not affect. By comparing the fluorescence intensity of a coumarin having a known concentration with the fluorescence intensity of the sample, .OH was quantified to derive a value of [.OH].

4). Solid content concentration Approximately 2 g of the prepared sample was placed in an aluminum dish and heated at 150 ° C. for 1 hour. The mass of the sample before and after heating was measured, and the solid content concentration was calculated from the difference.

5. Number average particle diameter A sample was appropriately diluted by adding a solvent so that the solid content in the sample was 1 to 20% by mass, and measured using a wet particle size analyzer (Microtrac UPA-9230, manufactured by Nihon Koki Co., Ltd.).

6). Film thickness The film thickness was measured using a film thickness measuring device (SPECTRA COOP, trade name “HandyLambda II THICKNESS”) equipped with a halogen light source device (MORITEX, trade name “MHF-D100LR”). And measured.

7). Appearance (color difference)
The color difference from the standard plate was determined using a color guide (BYK Gardner).

8). Contact angle (initial contact angle)
The contact angle of water at 20 ° C. was measured using a contact angle meter (trade name “DROP MASTER 500” manufactured by Kyowa Interface Science Co., Ltd.).

9. Weather resistance (water contact angle and color difference after 1000 hours exposure to SWOM)
Using the sunshine weather meter manufactured by Suga Test Instruments Co., Ltd., an exposure test (black panel temperature 63 ° C., rainfall 18 minutes / 2 hours) is performed, and the color difference between the exposure before and 1000 hours after the exposure is started And the contact angle was measured by the above method 8. The color difference before exposure was used as a standard, and the state change before and after exposure was evaluated as ΔE.

10. Antifouling (antifouling)
After the test plate was affixed to a fence facing a general road (traffic volume of about 500 to 1000 vehicles / day) for 1 year and contaminated, the degree of contamination was evaluated visually.
◎: dirt is not recognized,
○: Slightly dirty overall, but no dirt due to rain streaks
△: Some dirt due to rain streaks,
X: Dirt due to significant rain streaks.

11. Observation of underlying coating film deterioration After embedding the sample in an epoxy resin (trade name, Quetol 812), an ultrathin section having a thickness of 50 to 60 nm was prepared and supported by a ULTRACUT-N microtome (trade name) manufactured by Reichert, Germany. After loading on a mesh with a film attached, carbon deposition is carried out to make a sample for microscopy, and the cross-section of the coating film is observed with a TEM (HITACHI HF2000 type, acceleration voltage: 125 kV) to evaluate the deterioration state of the underlying coating film. did.
○: Deterioration of the undercoat is not observed,
X: Deterioration of the base coating film is observed.

[Reference example]
Synthesis of Polymer Emulsion Particle (B1-1) Aqueous Dispersion In a reactor having a reflux condenser, a dropping tank, a thermometer and a stirring device, 400 g of ion-exchanged water and 4.0 g of a 10% by mass dodecylbenzenesulfonic acid aqueous solution were added. After charging, the temperature in the reactor was heated to 80 ° C. with stirring. In this reactor, 54.5 g of dimethyldimethoxysilane, 34.4 g of phenyltrimethoxysilane, and 1.0 g of methyltrimethoxysilane, and 15.0 g of a 2% by weight aqueous solution of ammonium persulfate were added to the reactor. It was dripped simultaneously over about 2 hours in the state which maintained the inside temperature at 80 degreeC. Thereafter, the temperature in the reactor was maintained at 80 ° C., and stirring was continued for about 1 hour. Next, a mixed liquid composed of 12.3 g of n-butyl acrylate, 13.5 g of phenyltrimethoxysilane, 31.4 g of tetraethoxysilane, and 1.2 g of 3-methacryloxypropyltrimethoxysilane, and methyl methacrylate 24. 6 g, acrylic acid 1 g, reactive emulsifier (trade name “Adekaria Soap SR-1025”, manufactured by Asahi Denka Co., Ltd., 25% solids aqueous solution), reactive emulsifier (trade name “AQUALON KH-1025”) , Daiichi Kogyo Seiyaku Co., Ltd., 25% solid content aqueous solution) 0.7 g, ammonium persulfate 2% by weight aqueous solution 8.5 g, and a mixture of ion-exchanged water 255 g. It was dripped simultaneously over about 2 hours in the state kept at ° C. Further, the temperature in the reactor was maintained at 80 ° C. and stirring was continued for about 2 hours, and then the mixture was cooled to room temperature and filtered through a 100 mesh wire net. The solid content was adjusted to 10.0% by mass with ion-exchanged water, and an aqueous dispersion of polymer emulsion particles (B1-1) having a number average particle size of 120 nm was obtained as polymer particles.

[Example 1]
The value of [• O ₂ ⁻ ] measured by the above method 1 was 11.7 nM on 100 g of the polymer emulsion particle (B1-1) aqueous dispersion (solid content 10.0% by mass), measured by the above method 2. The silica-coated rutile-type titanium oxide sol (A-1) containing silica-coated rutile-type titanium oxide having a [H ₂ O ₂ ] value of 0.31 nM and a [.OH] value of 176 nM measured by the above method 3 ( Silica coating amount with respect to 100 parts by mass of titanium oxide: 8 parts by mass, solid content: 30% by mass, rod-shaped primary particles, arithmetic average value of particle length (l): 35 nm, arithmetic average value of particle diameter (d): 6 nm) 3.7 g, ethanol 13.9 g, and water 21.3 g were mixed and stirred to obtain a photocatalyst composition (C-1).
A glass plate having a size of 10 cm × 10 cm, in which an acrylic silicone resin was applied in advance with a film thickness of 1 μm, was prepared on another surface (front surface) of the glass plate on which one side (back surface) was black-printed. The said photocatalyst composition (C-1) was apply | coated to the single side | surface (surface) of this glass plate by the bar-coat method. Then, the test plate (D-1) in which the photocatalyst coating film was formed was obtained by drying the apply | coated photocatalyst composition (C-1) for 10 minutes at 70 degreeC. Various evaluation results of this test plate (D-1) are shown in Table 1.

[Example 2]
100 g of polymer emulsion particles (B1-1) in water dispersion (solid content: 10.0% by mass), water-dispersed colloidal silica having a number average particle diameter of 12 nm (trade name “Snowtex O”, manufactured by Nissan Chemical Industries, Ltd.) , 20% by mass of solid content) (B2) 50 g, 7.4 g of silica-coated rutile-type titanium oxide sol (A-1), 27.8 g of ethanol, and 92.6 g of water were mixed and stirred to obtain a photocatalytic composition. (C-2) was obtained.
A glass plate having a size of 10 cm × 10 cm, in which an acrylic silicone resin was applied in advance to a thickness of 1 μm on another surface (front surface) of a glass plate on which one side (back surface) was black-printed, was prepared. The photocatalyst composition (C-2) was applied to one side (surface) of this glass plate by a bar coating method. Then, the test plate (D-2) in which the photocatalyst coating film was formed was obtained by drying the apply | coated photocatalyst composition (C-2) at 70 degreeC for 10 minute (s). Various evaluation results of this test plate (D-2) are shown in Table 1.

[Example 3]
The value of [• O ₂ ⁻ ] measured by the above method 1 is 100 n (100% by weight of solid content) of the polymer emulsion particle (B1-1) aqueous dispersion of 0.5 nM, measured by the above method 2. The silica-coated rutile type titanium oxide sol (A-2) containing silica-coated rutile type titanium oxide having a [H ₂ O ₂ ] value of 0.19 nM and a [.OH] value of 130 nM measured by the above method 3 ( Silica coating amount with respect to 100 parts by mass of titanium oxide: 12 parts by mass, solid content: 30% by mass, rod-shaped primary particles, arithmetic average value of particle length (l): 35 nm, arithmetic average value of particle diameter (d): 6 nm) 3.7 g, ethanol 13.9 g, and water 21.3 g were mixed and stirred to obtain a photocatalyst composition (C-3).
A glass plate having a size of 10 cm × 10 cm, in which an acrylic silicone resin was applied in advance to a thickness of 1 μm on another surface (front surface) of a glass plate on which one side (back surface) was black-printed, was prepared. The photocatalyst composition (C-3) was applied to one surface (surface) of this glass plate by a bar coating method. Then, the test plate (D-3) in which the photocatalyst coating film was formed was obtained by drying the apply | coated photocatalyst composition (C-3) for 10 minutes at 70 degreeC. Various evaluation results of this test plate (D-3) are shown in Table 1.

[Example 4]
Polymer emulsion particles (B1-1) 100 g (solid content 10.0 mass%) of water dispersion colloidal silica having a number average particle diameter of 12 nm (trade name “Snowtex O”, manufactured by Nissan Chemical Industries, Ltd.) (Solid content 20% by mass) (B2) 50 g, silica-coated rutile type titanium oxide sol (A-2) 7.4 g, ethanol 27.8 g, and water 92.6 g were mixed and stirred to obtain a photocatalytic composition ( C-4) was obtained.
A glass plate having a size of 10 cm × 10 cm, in which an acrylic silicone resin was applied in advance to a thickness of 1 μm on another surface (front surface) of a glass plate on which one side (back surface) was black-printed, was prepared. The said photocatalyst composition (C-4) was apply | coated to the single side | surface (surface) of this glass plate by the bar coating method. Then, the test plate (D-4) in which the photocatalyst coating film was formed was obtained by drying the apply | coated photocatalyst composition (C-4) at 70 degreeC for 10 minute (s). Various evaluation results of this test plate (D-4) are shown in Table 1.

[Comparative Example 1]
The value of [· O ₂ ⁻ ] measured by the above method 1 was 36.4 nM, measured by the above method 2, on 100 g of the polymer emulsion particle (B1-1) aqueous dispersion (solid content 10.0% by mass). The silica-coated anatase-type titanium oxide manufactured by Ishihara Sangyo Co., Ltd., which contains silica-coated anatase-type titanium oxide having a [H ₂ O ₂ ] value of 0.45 nM and a [.OH] value of 419 nM measured by the above method 3. Aqueous dispersion (A-3) (trade name “MPT-422”, arithmetic average value of particle diameter (d) of primary particles: 30 nm, silica coating amount with respect to 100 parts by mass of titanium oxide: 15 parts by mass, solid content: 20 mass%) 5.6 g, 13.9 g of ethanol, and 19.4 g of water were mixed and stirred to obtain a photocatalyst composition (C-5).
TMI comment → (Since it seems to be a duplicate, "Titanium oxide (A-3) aqueous dispersion" has been deleted.)
A glass plate having a size of 10 cm × 10 cm, in which an acrylic silicone resin was applied in advance to a thickness of 1 μm on another surface (front surface) of a glass plate on which one side (back surface) was black-printed, was prepared. The said photocatalyst composition (C-3) was apply | coated to the single side | surface (surface) of this glass plate by the bar-coat method. Then, the test plate (D-5) in which the photocatalyst coating film was formed was obtained by drying the apply | coated photocatalyst composition (C-5) for 10 minutes at 70 degreeC. Various evaluation results of this test plate (D-5) are shown in Table 1.

[Comparative Example 2]
100 g of polymer emulsion particles (B1-1) in water dispersion (solid content: 10.0% by mass), water-dispersed colloidal silica having a number average particle diameter of 12 nm (trade name “Snowtex O”, manufactured by Nissan Chemical Industries, Ltd.) , 20 mass% solid content) (B2) 50 g, 11.1 g of silica-coated anatase type titanium oxide aqueous dispersion (A-3) manufactured by Ishihara Sangyo Co., Ltd., 27.8 g of ethanol, and 88.9 g of water. By mixing and stirring, a photocatalyst composition (C-6) was obtained.
A glass plate having a size of 10 cm × 10 cm, in which an acrylic silicone resin was applied in advance to a thickness of 1 μm on another surface (front surface) of a glass plate on which one side (back surface) was black-printed, was prepared. The said photocatalyst composition (C-6) was apply | coated to the single side | surface (surface) of this glass plate by the bar-coat method. Then, the test plate (D-6) in which the photocatalyst coating film was formed was obtained by drying the apply | coated photocatalyst composition (C-6) at 70 degreeC for 10 minute (s). Various evaluation results of this test plate (D-6) are shown in Table 1.

  If the metal compound for photocatalysts of this invention is used, the photocatalyst layer which exhibits a required photocatalytic activity can be provided on a base coating film without the need for a protective layer. A photocatalytic coating can be provided. The photocatalyst coating film of the present invention is excellent in self-cleaning properties, and is also useful as a coating agent for architectural exteriors, interior materials, exterior display applications, automobiles, displays, lenses and the like.

Claims (7)

Among the active oxygen species generated when a predetermined suspension containing the metal compound is irradiated with ultraviolet light having a wavelength of 365 nm, the value of [• O ₂ ⁻ ] is 15 nM or less. A metal compound for photocatalyst.   Among the active oxygen species generated when a predetermined suspension containing the metal compound is irradiated with ultraviolet light having a wavelength of 365 nm, the value of [.OH] is 400 nM or less. Metal compound for photocatalyst. Among the active oxygen species generated when a predetermined suspension containing the metal compound is irradiated with ultraviolet light having a wavelength of 365 nm, the value of [H ₂ O ₂ ] is 0. The metal compound for photocatalysts which is 4 nM or less.   The photocatalyst composition containing the metal compound for photocatalysts as described in any one of Claims 1-3, and a binder.   The photocatalyst composition according to claim 4, wherein the binder includes polymer particles and metal oxide particles other than the photocatalyst metal compound.   The photocatalyst coating film formed from the photocatalyst composition of Claim 4 or 5.   A photocatalyst-coated product comprising the photocatalyst coating film according to claim 6.