JP5905658B2 - Functional coating - Google Patents

Description

  The present invention relates to a functional coating film that can be used for a solar energy member.

  In recent years, the global warming phenomenon has heightened awareness of the environment, and a new energy system that does not generate greenhouse gases such as carbon dioxide is attracting attention. Renewable energy that is friendly to the environment, such as solar cell power generation and wind power generation, does not emit carbon dioxide and other gases that are said to induce global warming. Because of its superiority and ease of handling, solar cell power generation technology is rapidly spreading. However, there is a problem that the protective cover such as glass used on the surface of the solar cell becomes dirty due to accumulation of soot and sand dust, so that the light transmittance of sunlight decreases and the energy output of the solar cell decreases. It has become. Therefore, there is a demand for a practical antifouling technique that can suppress a decrease in energy output of the solar cell for a long period of time.

  In addition, a large-scale power generation plant is required to have high energy efficiency even at a few percent. For this purpose, for example, a solar cell cover glass surface may be coated with an antireflection coating. There is a problem that the output decreases due to dirt.

In Patent Document 1, a coating solution in which tungstic acid dissolved in ammonia water and distilled water are added is applied onto an anatase-type titanium oxide-containing layer, and a layer made of tungsten oxide is formed by baking at 700 ° C. Thus, a technique for forming a surface layer is disclosed. In this coated product, the anatase-type titanium oxide-containing layer having a photocatalytic function decomposes organic substances attached to the surface layer to make the surface hydrophilic, and the layer made of tungsten oxide maintains the surface hydrophilicity. Thereby, since the condensed water and water droplets adhering to the surface are easily spread over the entire surface, the dirt adhering to the surface can be washed away with rainwater or the like.
Patent Document 2 discloses an organic / inorganic composite composition excellent in transparency and antifouling property, but does not sufficiently disclose antireflection.

JP-A-10-114545 WO2007-069596 pamphlet

  The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a functional coating film having excellent antifouling properties and antireflection properties.

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) An organic-inorganic composite coating film containing the components (A) and (B), wherein the mass ratio of the components (A) and (B) is A / B = 1000/100 to 150/100, The film thickness is 80 to 300 nm, the refractive index of the coating film is 1.3 to 1.48, and the porosity of the coating film measured by the following method is 20 to 60%.
Component (C): Hydrolyzed condensate of a silicon compound represented by the following formula (1) (excluding colloidal silica obtained by a sol-gel method), and a mass ratio of component (A) and component (C) Is an organic-inorganic composite coating film, wherein C / A = 0.2 / 100 to 30/100.
Component (A): metal oxide having a number average particle diameter of 1 nm to 400 nm
(B) component; polymer emulsion particles having a number average particle diameter of 10 nm to 800 nm The component (B) includes the following components (b1) to (b4):
(B1) Component: Hydrolyzable silicon compound represented by the following formula (4) and a silane coupling agent having a vinyl polymerizable group SiWxRy (4)
(W is selected from an alkoxy group having 1 to 20 carbon atoms, a hydroxyl group, an acetoxy group having 1 to 20 carbon atoms, a halogen 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, and R is 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 1 to carbon atom. 20 represents an at least one hydrocarbon group 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, where x is an integer of 2 or more and 4 or less. And y is an integer of 0 or more and 2 or less, and x + y = 4.)
(B2) component: a vinyl monomer containing at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amide group, an amino group, and an ether group;
(B3) component: emulsifier,
(B4) component: water,
Polymer emulsion particles obtained by polymerizing a polymerization stock solution containing
SiX ₄ (1)
(In the formula, X represents a hydrolyzable group.)
Method of measuring porosity (Va) The surface of the coating film is observed at 250,000 times using an electron microscope, and the average value (2d) of the circumscribed circle equivalent diameter of the pores on the surface is obtained. The number of holes (n) in a square with a side of 1000 nm is obtained, and the volume (Vo) when the holes are converted into a sphere is obtained. The coating film volume (V1) is determined from the square area and film thickness of 1000 nm on each side, and the porosity is calculated from the result.
Vo = n4 / 3πd ³
Va (%) = Vo / V1 × 100
(2) The organic-inorganic composite coating film as described in (1) above, wherein the mass ratio of the component (A) to the component (B) is A / B = 150/100 to 450/100.
(3) The organic-inorganic composite coating film as described in (1) or (2) above, wherein the pore diameter of the coating film surface is 10 to 300 nm.
(4) The organic-inorganic composite coating film according to any one of (1) to (3), which is for a protective cover for solar cells.

  The functional coating film of the present invention is excellent in antifouling properties and antireflection properties.

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

The functional coating film of the present invention is obtained by applying a coating composition on at least one surface of a substrate and drying it to form an organic-inorganic composite coating film. The coating composition that can be used in the present invention includes the following components (A) and (B):
(A) component: a metal oxide having a particle size of 1 nm to 400 nm,
(B) component: polymer emulsion particles having a particle size of 10 nm to 800 nm,
Including
The component (B) includes the following components (b1) to (b4):
(B1) component: hydrolyzable silicon compound,
(B2) component: a vinyl monomer containing at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amide group, an amino group, and an ether group;
(B3) component: emulsifier,
(B4) component: water,
Polymer emulsion particles obtained by polymerizing a polymerization stock solution containing

The component (A) is considered to act as a curing agent for the component (B) by interacting with the component (B). Examples of the interaction include a hydrogen bond between the hydroxyl group that the component (A) generally has and the hydroxyl group, carboxyl group, amide group, amino group, and ether group that the component (B) has, or the component (A). Can be exemplified by the condensation (chemical bond) of the hydroxyl group generally possessed by the polymerization product of the component (b1) constituting the component (B).
Moreover, it is preferable that the component (A) exists while forming a continuous layer between the particles of the component (B) while interacting with the component (B). In this case, the light transmittance, weather resistance, and antifouling property of the resulting coating composition can be further improved.

  As the metal oxide used in the component (A), from the viewpoint of interaction with the component (B), for example, silicon dioxide, aluminum oxide, antimony oxide, titanium oxide, indium oxide, tin oxide, zirconium oxide, Examples thereof include lead oxide, iron oxide, calcium silicate, magnesium oxide, niobium oxide, and cerium oxide.

Of these, silicon dioxide (silica), aluminum oxide (alumina), antimony oxide, and complex oxides thereof having a large number of surface hydroxyl groups are preferred because of their strong interaction with the component (B). Further, the component (A) having a large number of surface hydroxyl groups is preferable because the density of hydroxyl groups on the surface of the coating film is increased by forming a continuous layer, and the hydrophilicity of itself is increased.
Here, two or more of these metal oxides can be used in combination as the component (A).

  The metal oxide used in the component (A) is a compound that expresses photocatalytic activity and / or hydrophilicity by light irradiation (hereinafter simply abbreviated as “photocatalyst”) from the viewpoint of imparting organic substance decomposability. Can be used). When a compound that expresses photocatalytic activity by light irradiation is used as the component (A), the surface of the functional coating film obtained can exhibit excellent decomposition activity and contamination resistance of the contaminating organic substance. In the present embodiment, “hydrophilic” means that the contact angle of water (23 ° C.) with respect to the surface of the measurement object is preferably 60 ° or less, more preferably 30 ° or less, and even more preferably 20 ° or less. Means that.

More specifically, examples of the photocatalyst include TiO ₂ , ZnO, SrTiO ₃ , BaTiO ₃ , BaTiO ₄ , BaTi ₄ O ₉ , K ₂ NbO ₃ , Nb ₂ O ₅ , Fe ₂ O ₃ , Ta ₂ O ₅ , K ₃ Ta ₃ Si ₂ O ₃ , WO ₃ , SnO ₂ , Bi ₂ O ₃ , BiVO ₄ , NiO, Cu ₂ O, RuO ₂ , CeO _2, etc., and at least selected from Ti, Nb, Ta, V Layered oxides having one element (for example, JP-A-62-274452, JP-A-2-172535, JP-A-7-24329, JP-A-8-89799, JP-A-8-89800) JP-A-8-89804, JP-A-8-198061, JP-A-9-248465, JP-A-10-99694, JP-A-10-2 It can be cited reference No. Publication 4165). Among these photocatalysts, TiO ₂ (titanium oxide) is preferable because it is harmless and has excellent chemical stability. As the titanium oxide, any of anatase type, rutile type and brookite type can be used.

Moreover, as a metal oxide used for the said (A) component, the metal oxide which has electroconductivity can be used from a viewpoint of expressing the antistatic performance etc. of the functional coating film obtained.
Examples of such conductive metal oxides include indium oxide (ITO) doped with tin, tin oxide (ATO) doped with antimony, tin oxide, and zinc oxide.
Examples of forms when the component (A) is used include powders, dispersions, and sols.
The dispersion or sol as used herein refers to primary particles in which the component (A) is in a concentration of 0.01 to 80% by mass, preferably 0.1 to 50% by mass in water and / or a hydrophilic organic solvent. And / or a state of being dispersed as secondary particles.

  Examples of the hydrophilic organic solvent include alcohols such as ethylene glycol, butyl cellosolve, n-propanol, isopropanol, n-butanol, ethanol and methanol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, tetrahydrofuran and dioxane, and the like. Examples include ethers, amides such as dimethylacetamide, dimethylformamide, dimethyl sulfoxide, nitrobenzene, and a mixture of two or more thereof.

The number average particle size of the component (A) observed in the dispersion or sol (may be a mixture of primary particles and secondary particles, or only primary particles or secondary particles). May be 1 nm to 400 nm, more preferably 1 nm to 100 nm, still more preferably 3 nm to 80 nm, and particularly preferably 5 nm to 50 nm. The number average particle diameter of the component (A) can contribute to the optical characteristics and the like of a functional coating film formed using the resulting coating composition. Particularly, when the thickness is 100 nm or less, the light transmittance of the obtained functional coating film can be greatly improved.
In addition, the number average particle diameter (simply abbreviated as “particle diameter”) in the present embodiment is a value measured according to the method of Examples described later.

The metal oxide (A) that can be used in the present invention is preferably colloidal silica from the viewpoint of handleability.
These colloidal silicas can be prepared and used by a sol-gel method, and commercially available products can also be used. For preparation by the sol-gel method, WernerStober et al; Colloidand Interface Sci. , 26, 62-69 (1968), Rickey D. et al. Badley et al; Lang muir 6, 792-801 (1990), Color Material Association Journal, 61 [9] 488-493 (1988). Colloidal silica is a dispersion of water or a water-soluble solvent of silica having silicon dioxide as a basic unit, and the particle diameter thereof needs to be 1 to 400 nm, preferably 1 to 100 nm, more preferably 5 ~ 50 nm. When the particle diameter is 1 nm or more, the storage stability of the coating liquid is good, and when it is 400 nm or less, the transparency is good. Colloidal silica having a particle size in the above range can be used in the state of an aqueous dispersion, whether acidic or basic, and is appropriately selected according to the stable region of the aqueous dispersion (B) to be mixed. be able to. Examples of acidic colloidal silica using water as a dispersion medium include, as commercial products, Snowtex (trademark) -O, Snowtex-OS, Snowtex-OL, Snowtex-OUP, and Snowtex-manufactured by Nissan Chemical Industries, Ltd. UP, Adelite (trademark) AT-20Q manufactured by Asahi Denka Kogyo Co., Ltd., Clevosol (trademark) 20H12 manufactured by Clariant Japan Co., Ltd., and clebosol 30CAL25 can be used.

  Examples of basic colloidal silica include silica stabilized by addition of alkali metal ions, ammonium ions, and amines. For example, SNOWTEX-20, SNOWTEX-30, SNOWTEX-C, and SNOWTEX-C manufactured by Nissan Chemical Industries, Ltd. Tex-C30, Snotex-CM40, Snotex-N, Snotex-N30, Snotex-K, Snotex-XL, Snotex-YL, Snotex-ZL, Snotex PS-M, Snotex PS-L Adelite AT-20, Adelite AT-30, Adelite AT-20N, Adelite AT-30N, Adelite AT-20A, Adelite AT-30A, Adelite AT-40, Adelite AT-50, etc. manufactured by Asahi Denka Kogyo Co., Ltd. Clariant Japan Co., Ltd. Kurebozoru 30R9, Kurebozoru 30R50, such Kurebozoru 50R50, DuPont Ludox (TM) HS-40, Ludox HS-30, Ludox LS, and the like Ludox SM-30.

  Examples of colloidal silica using a water-soluble solvent as a dispersion medium include MA-ST-M (methanol dispersion type having a particle size of 20 to 25 nm), IPA-ST (particle size 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. As a minor component, alumina, sodium aluminate or the like may be contained. 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 component (B) includes the following components (b1) to (b4):
(B1) component: hydrolyzable silicon compound,
(B2) component: a vinyl monomer containing at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amide group, an amino group, and an ether group;
(B3) component: emulsifier,
(B4) component: water,
Polymer emulsion particles obtained by polymerizing a polymerization stock solution containing As the component (B) thus obtained, it is preferable to use a compound in which the hydroxyl group derived from the component (b1) and the polymerization product of the component (b2) are combined by hydrogen bonding or the like. It is.

As said (b1) component, the compound represented by following formula (4), its condensation product, and a silane coupling agent can be illustrated.
SiWxRy (4)
(In the formula, W represents an alkoxy group having 1 to 20 carbon atoms, a hydroxyl group, an acetoxy group having 1 to 20 carbon atoms, a halogen atom, a hydrogen atom, an oxime group having 1 to 20 carbon atoms, an enoxy group, an aminoxy group, and an amide group. Represents at least one selected group, wherein R represents 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 carbon atom. It represents at least one hydrocarbon group selected from an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms substituted with a halogen atom, where x is 1 or more and 4; And y is an integer of 0 or more and 3 or less, and x + y = 4.)

  In addition, a silane coupling agent means the compound in which the functional group which has reactivity with organic substances, such as a vinyl polymerizable group, an epoxy group, an amino group, a methacryl group, a mercapto group, an isocyanate group, exists in a molecule | numerator.

Specific examples of the compound represented by the formula (4) include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetra-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-heptyltrimethoxysilane, n-octyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane Cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-c Ropropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2- Hydroxyethyltrimethoxysilane, 2-hydroxyethyltriethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyl Trimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltrimethoxy Silane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3- (meth) acryloxypropyl Trimethoxysilane, 3- (meth) acryloyloxypropyltriethoxysilane, 3- (meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysilane, 3-ureidopropyltri Trialkoxysilanes such as methoxysilane and 3-ureidopropyltriethoxysilane;

Dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane, di-n-butyldimethoxy Silane, di-n-butyldiethoxysilane, di-n-pentyldimethoxysilane, di-n-pentyldiethoxysilane, di-n-hexyldimethoxysilane, di-n-hexyldiethoxysilane, di-n-heptyl Dimethoxysilane, di-n-heptyldiethoxysilane, di-n-octyldimethoxysilane, di-n-octyldiethoxysilane, di-n-cyclohexyldimethoxysilane, di-n-cyclohexyldiethoxysilane, diphenyldimethyl Kishishiran, diphenyl diethoxy silane, 3- (meth) acryloyl dialkoxysilane such as propyl methyl dimethoxy silane;
Monoalkoxysilanes such as trimethylmethoxysilane and trimethylethoxysilane;
Etc. Moreover, these can be used individually or in mixture of 2 or more types.

As the component (b1), a silicon alkoxide having a phenyl group (for example, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, etc.) can be used. When a silicon alkoxide having a phenyl group is used, the polymerization stability in the presence of water and an emulsifier is good, which is preferable.
Furthermore, as said (b1) component, the silane coupling agent which has a thiol group, the following (b1-1) component,
(B1-1) Component: A hydrolyzable silicon compound having a vinyl polymerizable group may be included. When these are used, the long-term antifouling property of the obtained functional coating film is good, which is preferable.
Examples of the silane coupling agent having a thiol group include 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

  Examples of the component (b1-1) include 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, and 3- (meth) acryloyloxypropylmethyldimethoxysilane. 3- (meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, 2-trimethoxysilylethyl vinyl ether Examples thereof include silane coupling agents having a vinyl polymerizable group.

  These silane coupling agents can generate chemical bonds by copolymerization or chain transfer reaction with the component (b2) described later. For this reason, when a silane coupling agent having a vinyl polymerizable group or a thiol group is used by mixing or combining with the above-described component (b1), the polymerization product of (b1) and the component (b2) described later These polymerization products can be combined by chemical bonding.

Examples of the “vinyl polymerizable group” referred to as the component (b1-1) include a vinyl group and an allyl group, and among them, a 3 (meth) acryloxypropyl group is preferable.
Moreover, as said (b1) component, the following (b1-2) components,
(B1-2) Component: A cyclic siloxane oligomer may be included. When the said (b1-2) component is used, the softness | flexibility of the functional coating film obtained becomes more favorable, and is suitable.

As said cyclic siloxane oligomer, the compound represented by following formula (5) can be illustrated.
(R ′ ₂ SiO) m (5)
(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.)
Of these, cyclic dimethylsiloxane oligomers such as octamethylcyclotetrasiloxane are preferred from the viewpoint of reactivity.

In addition, when the said (b1) component is used as a condensation product, the polystyrene conversion weight average molecular weight (by GPC method) of the said condensation product becomes like this. Preferably it is 200-5000, More preferably, it is 300-1000.
The ratio (b1) / (B) (mass ratio) between the component (b1) and the component (B) described later is preferably 0.01 / 100 to 80/100, from the viewpoint of polymerization stability. Preferably they are 0.1 / 100-70 / 100, Furthermore, 0.2 / 100-40 / 100.

On the other hand, the ratio (b1-1) / (B) (mass ratio) between the component (b1-1) and the component (B) is preferably 0.01 / 100 to from the viewpoint of polymerization stability. 20/100, more preferably 0.5 / 100 to 10/100.
The ratio (b1-1) / (b2) (mass ratio) between the component (b1-1) and the component (b2) is preferably 0.1 / 100 to from the viewpoint of polymerization stability. 100/100, more preferably 0.5 / 100 to 50/100.
On the other hand, the ratio (b1-2) / (B) (mass ratio) between the component (b1-2) and the component (B) is preferably 0.01 / 100 to 20 from the viewpoint of hydrophilicity. / 100, more preferably 0.5 / 100 to 5/100.
The ratio (b1-2) / (b2) (mass ratio) between the component (b1-2) and the component (b2) is preferably 0.5 / 100 to from the viewpoint of polymerization stability. 50/100, more preferably 1.0 / 100 to 20/100.

The component (b2) is a vinyl monomer containing at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amide group, an amino group, and an ether group.
Examples of the hydroxyl group-containing vinyl monomer include various hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate; Various hydroxyl group-containing vinyl ethers such as hydroxyethyl vinyl ether or 4-hydroxybutyl vinyl ether; Various hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether; Monoesters of polyoxyalkylene glycols obtained from polyether polyols and various unsaturated carboxylic acids such as represented by (meth) acrylic acid; various hydroxyl group-containing monomers as described above With adducts with various lactones, such as represented by ε-caprolactone, or various epoxy group-containing unsaturated monomers, such as represented by glycidyl (meth) acrylate, Adducts with various acids as typified by acetic acid and the like; Furthermore, various unsaturated carboxylic acids as typified by (meth) acrylic acid and the like, and “Cardura E” ( Various hydroxyl group-containing vinyl monomers such as adducts with various monoepoxy compounds other than epoxides of α-olefin, as represented by the trade name of the Dutch company Shell, etc. Is mentioned.

As the carboxyl group-containing vinyl monomer, various unsaturated carboxylic acids such as (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, crotonic acid, itaconic acid, maleic acid or fumaric acid; monomethyl itaconate, Monoesters of unsaturated dicarboxylic acids with saturated monohydric alcohols such as mono-n-butyl itaconate, monomethyl maleate, mono-n-butyl maleate, monomethyl fumarate, mono-n-butyl fumarate (Half esters);
Monovinyl esters of various saturated dicarboxylic acids such as monovinyl adipate or monovinyl succinate; various saturated polycarboxylic anhydrides such as succinic anhydride, glutaric anhydride, phthalic anhydride or trimellitic anhydride Addition reaction products with various hydroxyl group-containing vinyl monomers listed above; and monomers obtained by addition reaction of various carboxyl group-containing monomers with lactones as described above Etc.

  Examples of the amide group-containing vinyl monomer include N-alkyl or N-alkylene-substituted (meth) acrylamide.

  More specifically, for example, N-methylacrylamide, N-methylmethacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N-ethylmethacrylamide N-methyl-N-ethylacrylamide, N-methyl-N-ethylmethacrylamide, N-isopropylacrylamide, Nn-propylacrylamide, N-isopropylmethacrylamide, Nn-propylmethacrylamide, N-methyl- Nn-propylacrylamide, N-methyl-N-isopropylacrylamide, N-acryloylpyrrolidine, N-methacryloylpyrrolidine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acrylo Ruhexahydroazepine, N-acryloylmorpholine, N-methacryloylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, N, N'-methylenebisacrylamide, N, N'-methylenebismethacrylamide, N-vinylacetamide, dye Acetone acrylamide, diacetone methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, etc. can be mentioned.

  Examples of amino group-containing vinyl monomers include 2-dimethylaminoethyl (meth) acrylate, 2-diethylaminoethyl (meth) acrylate, 2-di-n-propylaminoethyl (meth) acrylate, 3-dimethylaminopropyl (meth) ) Various tertiary amino group-containing (meth) acrylic esters such as acrylate, 4-dimethylaminobutyl (meth) acrylate or N- [2- (meth) acryloyloxy] ethylmorpholine; vinylpyridine, N-vinyl Various tertiary amino group-containing aromatic vinyl monomers such as carbazole N-vinylquinoline; N- (2-dimethylamino) ethyl (meth) acrylamide, N- (2-diethylamino) ethyl (meth) acrylamide N- (2-di-n-propylamino) ethyl (meth) acrylate Various tertiary amino acids such as luamide, N- (3-dimethylamino) propyl (meth) acrylamide, N- (4-dimethylamino) butyl (meth) acrylamide or N- [2- (meth) acrylamide] ethylmorpholine Group-containing (meth) acrylamides; N- (2-dimethylamino) ethylcrotonamide, N- (2-diethylamino) ethylcrotonamide, N- (2-di-n-propylamino) ethylcrotonamide, Various tertiary amino group-containing crotonic acid amides such as N- (3-dimethylamino) propyl crotonic acid amide or N- (4-dimethylamino) butyl crotonic acid amide; 2-dimethylaminoethyl vinyl ether, 2-diethylamino Ethyl vinyl ether, 3-dimethylaminopropyl vinyl ether Or 4, such as dimethylamino-butyl vinyl ether, tertiary amino group-containing vinyl ethers of various or the like.

  Examples of ether group-containing vinyl monomers include various polyether chains such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene higher fatty acid ester, and polyoxyethylene-polyoxypropylene block copolymer. Examples thereof include vinyl ethers, allyl ethers or vinyl monomers such as (meth) acrylic acid esters having a side chain. As specific examples, Bremer PE-90, PE-200, PE-350, PME-100, PME-200, PME-400, AE-350 [above, manufactured by NOF Corporation], MA-30, MA- 50, MA-100, MA-150, RA-1120, RA-2614, RMA-564, RMA-568, RMA-1114, MPG130-MA [above, manufactured by Nippon Emulsifier Co., Ltd.]. Here, as for the oxyethylene unit of a polyoxyethylene chain, 2-30 are preferable. If it is less than 2, the flexibility of the coating film becomes insufficient, and if it exceeds 30, the coating film becomes soft and the blocking resistance is poor.

As said (b2) component, it is preferable to use the vinyl monomer which has a secondary and / or tertiary amide group from a viewpoint of improving a hydrogen bond property with another component more. In particular, a vinyl monomer having a tertiary amide group is preferable from the viewpoint of hydrogen bonding strength.
The ratio (b2) / (B) (mass ratio) between the component (b2) and the component (B) is preferably 0.05 / 1 to 1/1, more preferably from the viewpoint of polymerization stability. Is 0.1 / 1 to 0.8 / 1, more preferably 0.2 / 1 to 0.5 / 1.
The ratio (b2) / (A) (mass ratio) between the component (b2) and the component (A) is preferably from the viewpoint of hydrogen bondability with the component (A) and blending stability. 0.05 / 1 to 1/1, more preferably 0.1 / 1 to 0.8 / 1, and further 0.2 / 1 to 0.5 / 1.
It is.

Examples of the component (b3) include acidic emulsifiers such as alkylbenzenesulfonic acid, alkylsulfonic acid, alkylsulfosuccinic acid, polyoxyethylene alkylsulfuric acid, polyoxyethylenealkylarylsulfuric acid, polyoxyethylene distyrylphenyl ether sulfonic acid, Anionic surfactants such as alkali metal (Li, Na, K, etc.) salts of emulsifiers, ammonium salts of acidic emulsifiers, fatty acid soaps;
Quaternary ammonium salts such as alkyltrimethylammonium bromide, alkylpyridinium bromide, imidazolinium laurate, pyridinium salts, imidazolinium salt type cationic surfactants;
Nonionic surfactants such as polyoxyethylene alkyl aryl ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene oxypropylene block copolymer, polyoxyethylene distyryl phenyl ether;
Etc. These can be used alone or in combination of two or more.

As the component (b3), from the viewpoint of improving the water dispersion stability of the component (B) to be obtained, and from the viewpoint of improving the long-term antifouling property of the functional coating film to be obtained, a radical polymerizable double It is preferable to use a reactive emulsifier having a bond.
More specifically, the reactive emulsifier includes, for example, a vinyl monomer having a sulfonic acid group or a sulfonate group, a vinyl monomer having a sulfate ester group, an alkali metal salt thereof, an ammonium salt, a polyoxyethylene, etc. Examples thereof include a vinyl monomer having a nonionic group and a vinyl monomer having a quaternary ammonium salt.

Examples of the vinyl monomer having a sulfonic acid group or a sulfonate group include, for example, a radically polymerizable double bond, and partly by a substituent such as an ammonium salt, a sodium salt, or a potassium salt of the sulfonic acid group. Selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkyl ether group having 2 to 4 carbon atoms, a polyalkyl ether group having 2 to 4 carbon atoms, a phenyl group, a naphthyl group, and a succinic acid group. A compound having a substituent;
A vinyl sulfonate compound having a vinyl group to which a substituent is bonded, such as an ammonium salt, sodium salt or potassium salt of a sulfonic acid group;
Etc.

As the vinyl monomer having a sulfate ester group, for example, it has a radical polymerizable double bond and is partially substituted by a substituent such as an ammonium salt, sodium salt or potassium salt of the sulfate ester group. , A compound having a substituent selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkyl ether group having 2 to 4 carbon atoms, a polyalkyl ether group having 2 to 4 carbon atoms, a phenyl group, and a naphthyl group. It is done.
Specific examples of the compound having a succinic acid group partially substituted with a substituent such as ammonium salt, sodium salt or potassium salt of the sulfonic acid group include allylsulfosuccinate. More specifically, for example, Eleminol JS-2 (trade name) (manufactured by Sanyo Chemical Co., Ltd.), Latemuru S-120, S-180A or S-180 (trade name) (manufactured by Kao Corporation), etc. Can do.

  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. Specific examples include, for example, Aqualon HS-10 or KH-1025 (trade name) (Daiichi Kogyo Seiyaku Co., Ltd.), Adeka Soap SE-1025N or SR-1025 (trade name) (Asahi Denka Kogyo Co., Ltd.) Manufactured).

Specific examples of the vinyl monomer having a nonionic group include, for example, 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, manufactured by Dai-ichi Pharmaceutical Co., Ltd.).
The amount of the component (b3) used is preferably 10 parts by mass or less, more preferably 0.001 to 5 parts by mass with respect to 100 parts by mass of the component (B) from the viewpoint of polymerization stability.

The component (B) is polymer emulsion particles obtained by polymerizing a polymerization stock solution containing the components (b1) to (b3) described above and the component (b4) (that is, “water”). The amount of the component (b4) used is preferably 30 to 99.9% by mass as the content in the polymerization stock solution from the viewpoint of polymerization stability.
In addition to the components (b1) to (b4), various components can be further mixed in the polymerization stock solution.

First, the polymerization stock solution contains the following component (b5):
Component (b5): other vinyl monomer copolymerizable with component (b2),
Can be mixed. The use of such component (b5) means that the properties of the polymerization product to be produced (glass transition temperature, molecular weight, hydrogen bonding force, polarity, dispersion stability, weather resistance, polymerization of hydrolyzable silicon compound (b1)) From the viewpoint of controlling compatibility with the product.
Examples of the component (b5) include acrylic acid esters, methacrylic acid esters, aromatic vinyl compounds, vinyl cyanides, epoxy group-containing vinyl monomers, carbonyl group-containing vinyl monomers, anionic vinyl monomers. Examples thereof include a monomer containing a functional group such as a monomer.

The proportion of the component (b5) in the total vinyl monomer is preferably 0.001 to 30% by mass, and more preferably 0.05 to 10% by mass. The use amount is such that the glass transition temperature, molecular weight, hydrogen bonding force, polarity, dispersion stability, weather resistance, compatibility with the polymerization product of the hydrolyzable silicon compound (b1), and the like are controlled. To preferred.
Further, a chain transfer agent can be mixed in the polymerization stock solution.

  Examples of such chain transfer agents include alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan and t-dodecyl mercaptan; aromatic mercaptans such as benzyl mercaptan and dodecyl benzyl mercaptan; thiomalic acid and the like. Thiocarboxylic acids or their salts or their alkyl esters, or polythiols, diisopropylxanthogen disulfide, di (methylenetrimethylolpropane) xanthogen disulfide and thioglycol, and allyl compounds such as dimers of α-methylstyrene be able to.

The amount of these chain transfer agents to be used is preferably 0.001 to 30 parts by mass, more preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the total amount of all vinyl monomers. Setting the amount to be used is suitable from the viewpoint of polymerization stability.
Furthermore, a dispersion stabilizer can be mixed in the polymerization stock solution.

Examples of such a 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 resins, poly Synthetic or natural water-soluble or water-dispersible various water-soluble polymer substances such as acrylic acid (salt), polyacrylamide, water-soluble or water-dispersible acrylic resin, and the like, one or more of these Mixtures can be used.
The amount of these dispersion stabilizers used is preferably 10 parts by mass or less, more preferably 0.001 to 5 parts by mass with respect to 100 parts by mass of the polymer emulsion particles (B).
The polymerization of the polymerization stock solution described above is preferably carried out in the presence of a polymerization catalyst.

  Examples of the polymerization catalyst for the component (b1) include hydrogen halides such as hydrochloric acid and hydrofluoric acid, carboxylic acids such as acetic acid, trichloroacetic acid, trifluoroacetic acid and lactic acid, and sulfonic acids such as sulfuric acid and p-toluenesulfonic acid. Acid emulsifiers such as alkylbenzene sulfonic acid, alkyl sulfonic acid, alkyl sulfosuccinic acid, polyoxyethylene alkyl sulfuric acid, polyoxyethylene alkyl aryl sulfuric acid, polyoxyethylene distyryl phenyl ether sulfonic acid, acidic or weakly acidic inorganic salts, phthalates Acid compounds such as acid, phosphoric acid and nitric acid; sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, tetramethylammonium chloride, tetramethylammonium hydroxide, tributylamine, diazabicycloundecene, ethylene Basic compounds such as amines, diethylenetriamine, ethanolamines, γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl) -aminopropyltrimethoxysilane; tin compounds such as dibutyltin octylate and dibutyltin dilaurate Etc.

Among them, as the polymerization catalyst for the hydrolyzable silicon compound (b1), not only the 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.
The polymerization catalyst for the component (b2) is preferably a radical polymerization catalyst that undergoes radical decomposition by heat or a reducing substance to cause addition polymerization of a vinyl monomer. Water-soluble or oil-soluble persulfates, peroxides, azobis compounds and the like are preferably used. More specifically, for example, potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, 2,2-azobisisobutyronitrile, 2, Examples include 2-azobis (2-diaminopropane) hydrochloride, 2,2-azobis (2,4-dimethylvaleronitrile), and the like.

  In addition, as a usage-amount of a polymerization catalyst, Preferably it is 0.001-5 mass parts with respect to 100 mass parts of all the vinyl monomers. When acceleration of the polymerization rate and polymerization at a low temperature of 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. is there.

In the present embodiment, the polymerization of the component (b1) and the polymerization of the component (b2) can be carried out separately. This is preferable because it can be achieved.
As a method for obtaining the component (B), so-called emulsion polymerization in which the emulsifier polymerizes the component (b1) and the component (b2) in the presence of a sufficient amount of water to form micelles is suitable. Yes.

As a method of emulsion polymerization, for example, the component (b1) and the component (b2), and further, the component (b3) as necessary, as they are or in an emulsified state, in a lump or divided, or continuously And a method of polymerizing at a reaction temperature of about 30 to 150 ° C. in the presence of the polymerization catalyst, preferably from atmospheric pressure to 10 MPa as necessary. In some cases, the polymerization may be carried out at a higher pressure or lower temperature.
In addition, as a mixing | blending of superposition | polymerization stock solution, from a viewpoint of superposition | polymerization stability, the amount of final solid content is 0.1-70 mass%, Preferably it is 1-55 mass% of said (b1)-(b4). Each component is preferably blended.

  Furthermore, when performing the emulsion polymerization, it is preferable to use a seed polymerization method from the viewpoint of appropriately growing or controlling the particle diameter. The seed polymerization method is a method in which emulsion particles (seed particles) are previously present in an aqueous phase for polymerization. The pH in the polymerization system when performing the seed polymerization method is preferably 1.0 to 10.0, 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 addition, as a method of obtaining the component (B), the component (b1) and the component (b2) in the presence of the component (b3) and the component (b4) necessary for polymerizing the component (b1). A method in which water is added until the polymerization product becomes an emulsion after the components are polymerized in the presence of a solvent, if necessary, can also be applied.
As the component (B), from the viewpoint of improving the substrate adhesion of the coating film formed using the resulting coating composition and the adhesion between the coating films, the core layer and the core layer 1 are coated. It is preferable to have a core / shell structure including a layer or two or more shell layers. As a method for forming the core / shell structure, multistage emulsion polymerization in which the emulsion polymerization is performed in multiple stages is very useful.

  More specifically as an example of multi-stage emulsion polymerization, for example, as the first stage, in the presence of the component (b3) and the component (b4), a group consisting of the components (b1), (b2), and (b5) At least one selected from the above is polymerized to form seed particles, and in the second stage, in the presence of the seed particles, the component (b1) and the component (b2), and further, if necessary (b5) ) Polymerization is carried out by adding a polymerization stock solution containing the component (two-stage polymerization method). When carrying out multi-stage emulsion polymerization of three or more stages, for example, as a third stage, polymerization is carried out by adding a polymerization stock solution further containing the component (b1) and the component (b2) and, if necessary, the component (b5). be able to. Such a method is also suitable from the viewpoint of polymerization stability.

  In the two-stage polymerization method, as a mass ratio of the solid content mass (M1) in the polymerization stock solution used in the first stage and the solid content mass (M2) in the polymerization stock solution added in the second stage, From the viewpoint of polymerization stability, (M1) / (M2) = 9/1 to 1/9, more preferably 8/2 to 2/8.

Further, as the core / shell structure, from the viewpoint of polymerization stability, the particle size distribution (volume average particle size / number average particle size) of the seed particles does not change greatly, and the particles are obtained by the second stage polymerization. It is preferable to have a structure with an increased diameter. The volume average particle diameter can be measured in the same manner as the number average particle diameter.
The core / shell structure can be observed, for example, by morphological observation using a transmission electron microscope or the like, analysis by viscoelasticity measurement, or the like.
The glass transition temperature (Tg) of the core layer having the core / shell structure is preferably 0 ° C. or lower. In this case, the functional coating film obtained is excellent in flexibility at room temperature, and cracks and the like when it is thickened are less likely to occur, which is preferable.
In addition, Tg in this Embodiment can be measured with a differential scanning calorimeter (DSC).

The particle size of the component (B) is 10 nm to 800 nm. By adjusting the particle diameter to such a range and forming the composition in combination with the component (A) having a particle diameter of 1 nm to 400 nm, the coating film refractive index without causing a significant decrease in light transmittance, Apparent porosity can be controlled and antifouling property is good. Moreover, it is preferable that the particle diameter of the said (B) component shall be 10 nm-100 nm from a viewpoint of the light transmittance improvement of the functional coating film obtained, and also 20 nm-80 nm are preferable.
The ratio (A) / (B) (mass ratio) of the component (A) to the component (B) is 1000/100 to 400/100, more preferably 150/100 to 350/100, and even 200 / 100-300 / 100. The coating composition blended in this range is preferable because a functional coating film having a low coating film refractive index and a high light transmittance and excellent antifouling property can be realized.

  The ratio (SA) / (SB) of the surface area (SA) of the component (A) and the surface area (SB) of the component (B) is preferably in the range of 0.001 to 1000. The surface area can be calculated from the particle diameter of each of the component (A) and the component (B) and the blending mass number.

In the coating composition of the present embodiment, additive components that are usually added to and blended with paints and molding resins, for example, light stabilizers, ultraviolet absorbers, thickeners, depending on the application and usage method. Leveling agent, thixotropic agent, antifoaming agent, freezing stabilizer, matting agent, crosslinking reaction catalyst, pigment, curing catalyst, crosslinking agent, filler, anti-skinning agent, dispersing agent, wetting agent, antioxidant, UV absorbers, rheology control agents, film-forming aids, rust inhibitors, dyes, plasticizers, lubricants, reducing agents, antiseptics, antifungal agents, deodorants, anti-yellowing agents, antistatic agents or electrification A regulator or the like can be selected or combined depending on the purpose.
As the light stabilizer, for example, a hindered amine light stabilizer is preferably used. Among these, a radical polymerizable light stabilizer having a radical polymerizable double bond in the molecule is preferable.

  Moreover, as said ultraviolet absorber, an organic type ultraviolet absorber can be mentioned, for example. Examples of such organic ultraviolet absorbers include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and triazine ultraviolet absorbers. Among these, it is preferable to use a radical polymerizable ultraviolet absorber having a radical polymerizable double bond in the molecule. Moreover, a benzotriazole type ultraviolet absorber and a triazine type ultraviolet absorber having high ultraviolet absorbing ability are preferable.

The light stabilizer is preferably used in combination with the organic ultraviolet absorber. Using both in combination can contribute to improving the weather resistance of the resulting coating composition.
Moreover, these organic ultraviolet absorbers, light stabilizers, and various additive components can be simply blended with the component (A) and the component (B), or the component (B) is synthesized. It is also possible to coexist when doing so.

The component (C) is a hydrolysis condensate of a silicon compound represented by the following formula (1), the following formula (2), or the following formula (3). As the silicon compound, a hydrolyzable silicon compound (c1) represented by the following general formula (1) and a hydrolyzable silicon compound (c2) represented by the general formula (2) can be used.
R ¹ _n SiX _4-n (1)
(Wherein R ¹ represents hydrogen or an alkyl group having 1 to 10 carbon atoms, an alkenyl group, an alkynyl group or an aryl group. Further, a halogen group, a hydroxy group, a mercapto group, an amino group, ( It may have a functional group such as a (meth) acryloyl group, an epoxy group, etc. X represents a hydrolyzable group, n is an integer of 0 to 3. The hydrolyzable group is a group that generates a hydroxyl group by hydrolysis. And may be any halogen atom, alkoxy group, acyloxy group, amino group, phenoxy group, oxime group, etc.)
X ₃ Si—R ² _n —SiX ₃ (2)
(Wherein X represents a hydrolyzable group, R ² represents an alkylene group having 1 to 6 carbon atoms or a phenylene group, and n is 0 or 1)

  Specific examples of hydrolyzable silicon compounds (c1, c2) include tetramethoxysilane, tetraethoxysilane, tetra (n-propoxy) silane, tetra (i-propoxy) silane, and tetra (n-butoxy) silane. , Tetra (i-butoxy) silane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane , Propyltrimethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxysilane, diethoxysilane, methyldimethyl Xysilane, methyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane, bis (triphenoxysilyl) methane, bis (trimethoxysilyl) ethane, bis ( Triethoxysilyl) ethane, bis (triphenoxysilyl) ethane, 1,3-bis (trimethoxysilyl) propane, 1,3-bis (triethoxysilyl) propane, 1,3-bis (triphenoxysilyl) propane, 1,4-bis (trimethoxysilyl) benzene, 1,4-bis (triethoxysilyl) benzene, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3- Hydroxypropyltrie Xysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acrylic Roxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, tetraacetoxysilane, tetrakis (trichloroacetoxy) silane, tetrakis (trifluoroacetoxy) silane, triacetoxysilane, tris (trichloro Acetoxy) silane, tris (trifluoroacetoxy) silane, methyltriacetoxysilane, methyltris (trichloroacetoxy) silane, tetrachlorosilane, Tetrabromosilane, tetrafluorosilane, trichlorosilane, tribromosilane, trifluorosilane, methyltrichlorosilane, methyltribromosilane, methyltrifluorobromo, tetrakis (methylethylketoxime) silane, tris (methylethylketoxime) silane, methyltris (methylethylketo) Ximem) silane, phenyltris (methylethylketoxime) silane, bis (methylethylketoxime) silane, methylbis (methylethylketoxime) silane, hexamethyldisilazane, hexamethylcyclotrisilazane, bis (dimethylamino) dimethylsilane, bis (diethylamino) dimethyl Examples include silane, bis (dimethylamino) methylsilane, and bis (diethylamino) methylsilane.

In addition, a hydrolyzable silicon compound (c3) represented by the following general formula (3) can also be suitably used. Specific examples include a partial hydrolysis condensate of tetramethoxysilane (trade name “M silicate 51” manufactured by Tama Chemical Industry Co., Ltd., trade name “MSI51” manufactured by Colcoat Co., Ltd.), trade names “MS51”, “MS56”. “Mitsubishi Chemical Co., Ltd.”, partially hydrolyzed condensate of tetoethoxysilane (trade names “Silicate 35”, “Silicate 45”, manufactured by Tama Chemical Industry Co., Ltd., trade names “ESI 40”, “ESI 48” )), A co-hydrolyzed condensate of tetramethoxysilane and tetraethoxysilane (trade name “FR-3” manufactured by Tama Chemical Industry Co., Ltd., trade name “EMSi48” manufactured by Colcoat Co., Ltd.) Can do.
R ³ — (O—Si (OR ³ ) ₂ ) _n —OR ³ (3)
(In the formula, ^{R 3} .n represents an alkyl group having 1 to 6 carbon atoms is an integer of 2-8.)

The said hydrolysable silicon compound can be used individually or in mixture of 2 or more types. The hydrolyzable silicon compound can be added after advance hydrolysis and condensation in advance, but may be added to the metal oxide (A) and / or the emulsion particles (B).
The mass ratio of the component (A) to the component (C) is preferably C / A = 0.2 / 100 to 300/100, preferably C / A = 1/100 to 100/100, Furthermore, C / A = 30/100 to 75/100. C / A is 0.2 / 100 or more from the viewpoint of lowering the contact angle under high temperature conditions, and 300/100 from the viewpoint of the strength of the functional coating film.

As a base material used in the present invention, when used as a cover of a solar cell, for example, glass or resin is preferably used, and the transmittance in visible light is preferably 80% or more, and more preferably. Is 92% to 99%. A texture may be formed for the purpose of improving the light transmittance. The texture here is glass having a regular concavo-convex structure on one side or both sides of the glass.
Further, tempered glass, laminated glass, multilayer glass, and the like can be used depending on the purpose.
Examples of the resin include acrylic resins, polycarbonate resins, cyclic polyolefin resins, polyethylene terephthalate resins, ethylene-fluoroethylene copolymers, etc., and weathering agents such as ultraviolet absorbers for the purpose of imparting weather resistance to these resin substrates. May be further kneaded.
The coating composition of the present invention is not particularly limited, but can be prepared in a state dissolved or dispersed in a solvent such as water.

  In addition, the functional coating film of the present invention is, for example, coated on the substrate with the coating composition dispersed in a solvent such as water (sometimes abbreviated as “water dispersion”) and dried. Formed. Here, as solid content concentration of an aqueous dispersion, Preferably it is 0.01-60 mass%, More preferably, it is 1-40 mass%. The viscosity of the aqueous dispersion is preferably 0.1 to 100,000 mPa · s, preferably 1 to 10,000 mPa · s at 20 ° C. Further, examples of the coating method include spray spraying, flow coating, roll coating, brush coating, dip coating, spin coating, screen printing, casting, gravure printing, flexographic printing, and the like. Can be mentioned. In addition, the functional coating film is preferably subjected to heat treatment or ultraviolet irradiation at 20 ° C. to 500 ° C., more preferably 40 ° C. to 250 ° C., if desired, after drying the coating film on the substrate. It is also possible to do and form. For the purpose of repair, it is preferable to spray coat the functional coating film. In this case, it is possible to perform coating at an installed site, which is preferable. Moreover, when laminating again on a large functional coating film having a length exceeding 1 m, a method of obtaining a functional coating film by flow coating or dip coating is preferable from the viewpoint of handling and cost.

The coating film provided on the functional coating film of the present invention has a film thickness after drying of 10 nm to 1000 nm, preferably 50 nm to 750 nm, and more preferably 80 nm to 300 nm. When the thickness of the single layer is smaller than 10 nm, it becomes difficult to control the film thickness, and unevenness of the coating film occurs on the uneven substrate, and when it exceeds 1000 nm, for example, the absorption wavelength of silicon due to light interference Within the range, the effect of improving the light transmittance tends to decrease in the wavelength range of 500 nm to 1000 nm, which is relatively high in energy efficiency.
Here, the light transmittance of the present invention is the total light transmittance measured by NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.

  The refractive index of the functional coating film of the present invention is 1.3 to 1.48, preferably 1.35 to 1.45. The refractive index of the coating can be selected as appropriate depending on the substrate used, but if the refractive index is lower than 1.3, it cannot withstand a strong scratch test using sandblasting. There is. When the refractive index exceeds 1.48, the antireflection effect is reduced. Here, the refractive index of the present invention is a refractive index (633 nm) measured by FE-3000 manufactured by Otsuka Electronics.

  The pore diameter of the coating film surface of the present invention is preferably 2 to 500 nm, more preferably 5 to 400 nm, and further preferably 10 to 300 nm. The pore diameter on the surface of the coating film can be determined from observation 250,000 times the electron micrograph. The hole diameter is a hole formed in the surface of the coating film, such as a circle, an ellipse, or a rectangle. The maximum diameter or the maximum width of one hole that is visually observed in the range of 500 nm in length and 500 nm in width. It is. When the pore diameter of the present invention is smaller than 2 nm, the porosity of the coating film is low and the antireflection performance cannot be said to be sufficient, and when it is larger than 500 nm, the light transmittance decreases due to the roughness of the coating film surface. Sometimes.

  The vacancies of the present invention are those formed between metal oxide and emulsion particles, or vacancies formed when the solvent volatilizes. These pores may be formed inside the coating film. There is an effect of reducing the refractive index of the coating film due to the voids formed on the surface and inside of the coating film, that is, the voids of the coating film, and an antireflection effect can be imparted. The porosity here is preferably 60% or less. It is preferable that the porosity exceeds 60% from the viewpoint of antireflection, but it is difficult to say that the strength is lowered and practical. Therefore, from the viewpoint of antireflection and antifouling properties, the apparent porosity is preferably 20 to 60%, and more preferably 25 to 40%.

As an example for determining the porosity Va (%), the average value of the equivalent circle diameter per unit area (2d) of the pore diameter on the coating film surface and the number of included pores (n) are used to divide the pores into spheres. The volume (Vo) when converted to is obtained. It can be determined from the volume (Vo) of the converted sphere contained in the coating film volume (V1) having a film thickness of 1000 nm.
Vo = n4 / 3πd ³
Va (%) = Vo / V1 × 100

  Here, the equivalent circle diameter generally has the following definition. The projected area equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particles, and is also called the Heywood diameter. The projected circumference equivalent circle diameter is the diameter of a circle having a circumference equal to the circumference of the projected figure of the particle, and is mainly used for evaluating the shape of the particle. The circumscribed and inscribed circle equivalent diameters are the diameters of the circle circumscribed and inscribed on the projected image of the particle, and are mainly used for evaluating the shape of the particle. In addition to the above-mentioned equivalent circle diameter, there are the following three types of statistical diameters for measuring and displaying the particle diameter by microscopy. The Martin diameter is the length of a line segment that bisects the projected area of a particle in a fixed direction. The Feret diameter is the distance between two parallel lines in a certain direction between the particles. The maximum diameter in the fixed direction is the maximum width of each particle in a fixed direction.

Moreover, as a method of calculating | requiring porosity (Vb), it calculates | requires from the volume ratio (V) calculated | required from the preparation mass (W) and specific gravity (K) (document value) of the material which comprises a functional coating film, and a document value. Based on the refractive index (Nmeas) of the functional coating film obtained from the experiment, the refractive index (Nmeas) of the functional coating film calculated based on the refractive index (Nref) calculated from There is a way to ask.
Vb (%) = (Ncal-Nmeas) / (Ncal-1) × 100

The Bristow method is a method for obtaining the porosity by a physical method. This is a method for determining the saturated water absorption amount of a coating film by using a turntable type liquid absorption tester (manufactured by Kumagai Riki Co., Ltd.), and can be determined using a Lucas-Washburn theoretical formula.
V2 = (dtγcos θ / 4η) ^0.5
d: tube diameter, t: contact time, γ: surface tension, θ: contact angle, η: viscosity The porosity Vc (%) can be converted from the water absorption (V2) and the volume (V3) of the coating film. .
Vc (%) = V2 / V3 × 100

In addition, a known method such as a nitrogen adsorption method or a mercury intrusion method can also be used.
Moreover, since the intensity | strength of a coating film improves when the porosity which can be used by this invention is less than 20%, it can be used for a reflective mirror. When used for a reflecting mirror, the porosity is more preferably 10 to 20%.

In addition, when used as a reflecting mirror, the base material used in the present invention is, for example, metal plating or metal coating (for example, coating by vapor deposition) on a substrate such as glass, ceramic and plastic (resin). A planar or curved reflective substrate having a reflective layer formed by bonding the substrate and a metal plate or a metal foil together with a transparent adhesive, and having a sunlight reflecting function. Further, depending on the type of substrate and / or reflective layer used, the reflective base material is provided with a transparent layer laminated on the substrate and / or reflective layer for the purpose of protecting the substrate and / or reflective layer. May be. Examples of the material for the transparent layer include glass, acrylic resin, polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalate resin, and ethylene-fluoroethylene copolymer. These may be used alone or in combinations of two or more. Moreover, it is also preferable from a durable viewpoint to use the glass base material by which the mirror surface process was performed as a base material. The reflectance of these base materials in visible light is preferably 80% or more, and more preferably 85% or more.
The “coating film” referred to in the present embodiment is not necessarily a continuous film, and may be a discontinuous film, an island-shaped dispersion film, or the like.

Next, the present embodiment will be described more specifically with reference to examples and comparative examples. However, the present embodiment is not limited to the following examples unless it exceeds the gist. Various physical properties were evaluated by the following methods.
1. Total light transmittance The total light transmittance of the functional coating film was measured according to JIS-K7105 using a turbidimeter (NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.).
2. Refractive index A refractive index (633 nm) of the functional coating film was measured using a film thickness meter (FE-3000 manufactured by Otsuka Electronics Co., Ltd.).
3. Contact angle A drop of deionized water was placed on the outermost surface of the functional coating film, left at 23 ° C. for 10 seconds, and then measured using a contact angle meter (CA-X150 type contact angle meter manufactured by Kyowa Interface Science). did.
4). Pore diameter and porosity The surface of the coating film was observed at 250,000 times using an electron microscope, and the maximum diameter and the maximum width of the pore diameter on the surface were determined. Furthermore, the circumscribed circle equivalent diameter was determined. The volume of the coating film was determined from the area of a square having a side of 1000 nm and the film thickness, and the porosity was calculated from the result.

[Production Example 1] Synthesis of polymer emulsion particles (B-1) aqueous dispersion In a reaction vessel equipped with a stirrer, a reflux condenser, a dropping tank and a thermometer, 212 parts of water and 25 of "ADEKA rear soap SE1025N" 1 part of a% aqueous solution was added, and the inside of the reaction vessel was brought to 80 ° C. Next, 2 parts of acrylic acid, 2 parts of diacetone acrylamide, 51 parts of methyl methacrylate, 5 parts of butyl acrylate, and 1 part of 2-hydroxyethyl methacrylate were mixed, and this monomer mixture was mixed with “Adekari Soap SE1025N”. A mixture of 10 parts of a 25% aqueous solution and 10 parts of a 2% aqueous solution of ammonium persulfate was made into a pre-emulsion liquid by a homogenizer and added into the reaction vessel from a dropping tank over 2 hours. The temperature in the reaction vessel was kept at 80 ° C. during the addition and for another hour after the addition was completed. The number average particle size of the emulsion at this stage was 10 nm. Subsequently, 10 parts of a 2% aqueous solution of ammonium persulfate, 140 parts of N-isopropylacrylamide and 600 parts of water, 5 g of butyl acrylate, 10 g of phenyltrimethoxysilane, and 0.2 g of 3-methacryloxypropyltrimethoxysilane were added dropwise. Further, the addition was started in the reaction vessel, and the addition was completed over 2.5 hours. The liquid temperature in the reaction vessel was kept at 80 ° C. during the addition and for 1 hour after the completion of the addition, and then cooled to 50 ° C., and 780 parts of a 60% ethanol aqueous solution was gradually added into the reaction vessel. After the addition of the ethanol aqueous solution, the mixture was cooled to room temperature and adjusted to a solid content of 10%. A polymer emulsion particle (B-1) aqueous dispersion emulsion having a number average particle diameter of 100 nm was obtained.

[Production Example 2] Synthesis of polymer emulsion particles (B-2) aqueous dispersion A reactor having a reflux condenser, a dropping tank, a thermometer and a stirring device was charged with 1600 g of ion-exchanged water and 6 g of dodecylbenzenesulfonic acid. Thereafter, the temperature was raised to 80 ° C. with stirring. To this, a mixture of 185 g of dimethyldimethoxysilane and 117 g of phenyltrimethoxysilane was dropped over about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C., and then the temperature in the reaction vessel was 80 ° C. And stirring was continued for about 1 hour. Next, 86 g of butyl acrylate, 133 g of phenyltrimethoxysilane, 1.3 g of 3-methacryloxypropyltrimethoxysilane, 137 g of diethylacrylamide, 3 g of acrylic acid, a reactive emulsifier (trade name “ADEKA rear soap SR-1025” Asahi Denka Co., Ltd., 25% solid content aqueous solution) 13 g, ammonium persulfate 2 mass% aqueous solution 40 g, and ion-exchanged water 1900 g mixed solution with the temperature in the reaction vessel kept at 80 ° C. for about 2 hours It was dripped at the same time. Further, stirring was continued for about 2 hours in a state where the temperature in the reaction vessel was 80 ° C., then cooled to room temperature, filtered through a 100-mesh wire mesh, and the solid content was adjusted to 10.0% by mass with ion-exchanged water. A polymer emulsion particle (B) aqueous dispersion having a number average particle diameter of 70 nm was obtained.

[ Reference Example 1]
The product name “Snow Tech OS” (component (A)) manufactured by Nissan Chemical Industries, Ltd. was diluted with water to prepare a dispersion having a solid content of 10% by mass (number average particle size 8 nm). The obtained polymer emulsion was blended, and a coating composition was obtained by blending as shown in Table 1.
The obtained coating composition was spin-coated on white plate glass (thickness 2 mm, 6 × 6 cm square) so as to have a film thickness of 250 nm, and then dried at 70 ° C. for 30 minutes to obtain a functional coating film.

[ Reference Example 2]
A functional coating film was obtained in the same manner as in Reference Example 1 except that the coating composition was obtained with the formulation shown in Table 1.

[ Reference Example 3]
A functional coating film was obtained in the same manner as in Reference Example 1 except that the coating composition was obtained with the formulation shown in Table 1.

[Example 4]
The product name “Snow Tech OS” (component (A)) manufactured by Nissan Chemical Industries, Ltd. is diluted with water to prepare a dispersion (number average particle size 8 nm) having a solid content of 10% by mass. The resulting polymer emulsion was blended, and a coating composition was obtained by blending as shown in Table 1 with trade name “KBE-04” manufactured by Shin-Etsu Chemical Co., Ltd. as tetraethoxysilane (C).
The obtained coating composition was spin-coated on white plate glass (thickness 2 mm, 6 × 6 cm square) so as to have a film thickness of 250 nm, and then dried at 70 ° C. for 30 minutes to obtain a functional coating film.

[ Reference Example 5]
A functional coating film was obtained in the same manner as in Example 4 except that the coating composition was obtained with the formulation shown in Table 1.

[Comparative Example 1]
Evaluation was made using only the glass of the substrate.

[Comparative Example 2]
A functional coating film was obtained in the same manner as in Reference Example 1 except that the coating composition was obtained with the formulation shown in Table 1.

  Since the functional coating film provided by the present invention is excellent in antifouling property and antireflection property, the output of the solar cell can be maintained when a protective cover for solar cell is used.

Claims (4)

(A) It is an organic-inorganic composite coating film containing each component of (B), Comprising: Mass ratio of (A) component and (B) component is A / B = 1000 / 100-150 / 100, and film thickness is 80 to 300 nm, the refractive index of the coating film is 1.3 to 1.48, the porosity of the coating film measured by the following method is 20 to 60%,
Component (C): Hydrolyzed condensate of a silicon compound represented by the following formula (1) (excluding colloidal silica obtained by a sol-gel method), and a mass ratio of component (A) and component (C) Is an organic-inorganic composite coating film, wherein C / A = 0.2 / 100 to 30/100.
Component (A): metal oxide having a number average particle diameter of 1 nm to 400 nm
(B) component; polymer emulsion particles having a number average particle size of 10 nm to 800 nm The (B) component is the following components (b1) to (b4), (b1) component: represented by the following formula (4) Hydrolyzable silicon compound and silane coupling agent having vinyl polymerizable group SiWxRy (4)
(W is selected from an alkoxy group having 1 to 20 carbon atoms, a hydroxyl group, an acetoxy group having 1 to 20 carbon atoms, a halogen 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, and R is 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 1 to carbon atom. 20 represents an at least one hydrocarbon group 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, x being an integer of 2 or more and 4 or less. And y is an integer of 0 or more and 2 or less, and x + y = 4.)
(B2) component: a vinyl monomer containing at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amide group, an amino group, and an ether group;
(B3) component: emulsifier,
(B4) component: water,
Polymer emulsion particles obtained by polymerizing a polymerization stock solution containing
SiX ₄ (1)
(In the formula, X represents a hydrolyzable group.)
Method for Measuring Porosity (Va) The surface of the coating film is observed at 250,000 times using an electron microscope, and the average value (2d) of the circumscribed circle equivalent diameter of pores on the surface is obtained. The number of holes (n) in a square with a side of 1000 nm is obtained, and the volume (Vo) when the holes are converted into a sphere is obtained. The coating film volume (V1) is determined from the square area and film thickness of 1000 nm on each side, and the porosity is calculated from the result.
Vo = n4 / 3πd ³
Va (%) = Vo / V1 × 100   The organic / inorganic composite coating film according to claim 1, wherein the mass ratio of the component (A) to the component (B) is A / B = 150/100 to 450/100.   The organic-inorganic composite coating film according to claim 1 or 2, wherein the pore diameter of the coating film surface is 10 to 300 nm.   The organic-inorganic composite coating film according to any one of claims 1 to 3, which is used for a protective cover for solar cells.