JP5666803B2 - Energy conversion device member, reflector device and solar power generation system - Google Patents

Description

  The present invention relates to a coating composition, an energy conversion member, a reflector device, and a solar thermal power generation system.

  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. Environmentally friendly renewable energy 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, and therefore, research and development are being actively conducted as clean energy. In particular, solar cells and solar thermal power generation are attracting attention because of their safety and ease of handling.

  There are three types of typical solar thermal power generation methods: centralized (central tower), distributed (parabolic trough), and dish / sterling. The centralized system (central tower type) and distributed system (parabolic trough) can be expected to output in the hundreds of MW region, and can also be combined with conventional power generation technology for hybridization. The dish / Stirling method is suitable for use alone in developing countries because the output area is 5 to 50 kW.

  In either method, sunlight is condensed on a part by a reflecting mirror, and electric energy is obtained from the condensed heat by thermoelectric conversion. Therefore, the efficiency of collecting light without loss is important. As a factor that affects the efficiency, a decrease in reflectance due to contamination of the reflector is particularly problematic. Similarly, in a solar cell in which the light-receiving surface is protected by a protective cover made of glass or a weather-resistant resin film, the light transmittance is reduced because the protective cover becomes dirty with dust during long-term use. There is a similar problem that the energy conversion efficiency of the solar cell is lowered.

As a technique for preventing surface contamination, for example, Patent Document 1 discloses that tungstic acid and distilled water dissolved in ammonia water on an anatase-type titanium oxide-containing layer formed on the surface of a base material to be subjected to antifouling. A technique is disclosed in which a coating solution to which is added is applied and subjected to a baking treatment at 700 ° C. to form a surface layer made of tungsten oxide. In the member thus obtained, 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 surface layer made of tungsten oxide makes the surface hydrophilic. Sex is maintained. Thereby, since the condensed water and water droplets adhering to the surface of the member are easily spread over the entire surface, the surface can be prevented from being fogged. In Patent Document 2, a transparent photocatalyst layer obtained by adding 10 to 20% of titanium oxide fine particles having a particle diameter of 100 nm or less in a transparent paint is formed on the outermost surface of a reflecting mirror to prevent contamination for a long period of time. Thus, a technique for maintaining the reflectance is disclosed. Patent Document 3 discloses a composite material having a hydrophilic surface, which is bonded to a substrate and the surface of the substrate, and is made of TiO ₂ , ZnO, SnO ₂ , SrTiO ₃ , WO ₃ , Bi ₂ O ₃ , Fe. _A composite comprising a photocatalytic semiconductor material selected from the group consisting of ₂ O ₃ and a photocatalytic coating containing silica, wherein the surface of the coating exhibits hydrophilicity in response to photoexcitation of the photocatalytic semiconductor material A material is disclosed. Patent Documents 4 and 5 disclose techniques for expressing antifouling properties with a water-based organic-inorganic composite composition having a small environmental load.

JP-A-10-114545 JP-A 63-5301 Japanese Patent Publication No. 2756474 JP 2009-19072 A International Publication No. 2007-069596

However, from the viewpoint of a water-based material that has high transparency and exhibits high hydrophilicity immediately after formation and can maintain the high hydrophilicity for a long period of time, and an aqueous material that can form the coating film without baking at a high temperature. There was room for improvement in any of -5.
The present invention has been made in view of the above circumstances, and is an aqueous system that can form a coating film that has high transparency and exhibits high hydrophilicity immediately after formation, and can maintain the high hydrophilicity for a long period of time without baking at a high temperature. An object of the present invention is to provide a coating composition, a member for an energy conversion device, a reflector device, and a solar power generation system.

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] base material, (A1) component: colloidal silica having a particle size of 1 nm to 400 nm, (A2) component: photocatalyst having a particle size of 1 nm to 200 nm, and (B) component: a particle size of 10 nm to 800 nm A coating composition obtained by applying a coating composition containing polymer emulsion particles on the substrate and drying at 100 ° C. or lower, and providing the coating film as a protective member for a light reflector A device member ,
The component (B) comprises at least one functional group selected from the group consisting of (b1) component: hydrolyzable silicon compound and (b2) component: hydroxyl group, carboxyl group, amide group, amino group and ether group. A polymer emulsion obtained by polymerizing the component (b1) and the component (b2) in a polymerization stock solution containing a vinyl monomer having, (b3) component: emulsifier, and (b4) component: water. Particles,
The mass ratio of the total content of the component (A1) and the component (A2) to the content of the component (B) is 60/100 to 480/100, and the component (A1) relative to the total content The mass ratio of the content of is 85/100 to 99/100,
The coating composition further comprises (C) component: tetraethoxysilane,
The member for energy converters whose mass ratio of content of the said (C) component with respect to content of the said (A1) component is 1 / 100-100 / 100 .
[2]
The member for an energy conversion device according to [1], wherein a mass ratio of the content of the component (A1) to the total content is 95.3 / 100 to 98.5 / 100.
[3] The energy conversion according to [1] or [2], wherein the mass ratio of the content of the component (b2) to the content of the component (B) is 0.1 / 1 to 0.5 / 1. Device components .
[4] The mass ratio of the content of the component (b2) to the content of the component (A1) is 0.1 / 1 to 1/1, and any one of [1] to [3]. Energy conversion device member .
[5] Any one of [1] to [4], wherein the component (B) has a core / shell structure including a core layer and one or more shell layers covering the core layer. The member for energy converters as described in one.
[6] In the core layer, the mass ratio of the content of the component (b2) to the content of the component (b1) is 0.01 / 1 to 1/1, and in the outermost layer of the shell layer, [B1] The energy conversion device member according to [5], wherein the mass ratio of the content of the component (b2) to the content of the component is 0.1 / 1 to 5/1.
[7] The component (B) is polymer emulsion particles obtained by polymerizing the component (b1) and the component (b2) in the polymerization stock solution containing seed particles that form the core layer. The seed particles polymerize at least one component selected from the group consisting of the component (b1), the component (b2), and (b5) another vinyl monomer copolymerizable with the component (b2). The member for an energy conversion device according to [5] or [6], which is a particle obtained by the step.
[8] The energy conversion device member according to any one of [1] to [7], wherein the component (b2) is a vinyl monomer having a secondary and / or tertiary amide group .
[9 ] The member for an energy conversion device according to any one of [1] to [ 8 ], wherein the particle size of the component (B) is 10 to 100 nm.
[10] Before Kinurimaku refractive index of a 1.3 to 1.5, [1] the energy conversion device member according to any one of - [9].
[ 11 ] The member for an energy conversion device according to [ 10 ], wherein the coating film has a haze value of 10% or less.
[12 ] A reflector device comprising: the energy conversion device member according to any one of [1] to [11] ; and a support that supports the energy conversion device member from the side opposite to the coating film. .
[ 13 ] A solar thermal power generation system comprising: the reflector device according to [ 12 ] that collects sunlight, and a device that converts the heat of the collected sunlight into electrical energy.

  ADVANTAGE OF THE INVENTION According to this invention, the water-based coating composition which can be formed without baking at high temperature the coating film which has high transparency and high hydrophilicity immediately after formation, and can maintain the high hydrophilicity for a long period of time, the member for energy converters A reflector device and a solar thermal power generation system can be provided.

  Hereinafter, a mode for carrying out the present invention (hereinafter sometimes abbreviated as “this embodiment”) will be described in detail. The present invention is not limited to the following embodiment, and can be implemented with various modifications within the scope of the gist. 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 coating composition of the present embodiment includes (A1) component: colloidal silica having a particle size of 1 nm to 400 nm, (A2) component: titanium oxide sol having a particle size of 1 nm to 200 nm, and (B)) component: particle size. (B1) component: hydrolyzable silicon compound and (b2) component: hydroxyl group, carboxyl group, amide group, amino acid, and a coating composition comprising 10 nm to 800 nm polymer emulsion particles. (B1) component in a polymerization stock solution containing a vinyl monomer having at least one functional group selected from the group consisting of a group and an ether group, (b3) component: emulsifier, and (b4) component: water. And (b2) polymer emulsion particles obtained by polymerizing the component, the mass ratio of the total content of the component (A1) and the component (A2) to the content of the component (B) ((A1 A2) / B) is a 60 / 100-480 / 100, the mass ratio of the content of the component (A1) with respect to the total amount (A1 / (A1 + A2)) of 85 / 100-99 / 100.

  Moreover, the member for energy converters of this embodiment is provided with the base material and the coating film obtained by apply | coating the said coating composition on the base material, and making it dry at 100 degrees C or less, and the refractive index of a coating film is 1.3 to 1.5.

The component (A1) is considered to act as a curing agent for the component (B) by interacting with the component (B). Examples of the interaction include, for example, a hydrogen bond between a hydroxyl group that the component (A1) generally has and a hydroxyl group, carboxyl group, amide group, amino group, and ether group that the component (B) has, and a hydroxyl group that the component (A1) generally has. And condensation (chemical bond) with the polymerization product of the component (b1) constituting the component (B).
The component (A1) is preferably present while forming a continuous phase between the particles of the component (B) while interacting with the component (B). As a result, silica particles with high hydrophilicity always exist on the outermost surface of the coating film, so that high hydrophilicity can be obtained immediately after the coating film formation regardless of light irradiation, and transparency and weather resistance are also improved. It can be improved.

  The colloidal silica which is the component (A1) according to the present embodiment can be prepared and used by a sol-gel method, and a commercially available product can also be used. When colloidal silica is prepared by the sol-gel method, Werner Stober et al; Colloid and Interface Sci. , 26, 62-69 (1968), Rickey D .; It can be prepared with reference to the method described in Badley et al; Lang muir 6, 792-801 (1990), Journal of Color Material Association, 61 [9] 488-493 (1988). Colloidal silica is a dispersion of water or water-soluble solvent of silica having silicon dioxide as a basic unit, and its particle size (number average particle size) needs to be 1 nm to 400 nm, preferably 1 nm to It is 200 nm, more preferably 5 nm to 50 nm. If the particle diameter is 1 nm or more, the storage stability of the coating composition is good, and if it is 200 nm or less, the transparency of the coating film 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 depending on the stable region of the aqueous dispersion of component (B) mixed together. The pH can be appropriately selected.

Examples of acidic colloidal silica using water as a dispersion medium include, for example, commercially available products such as SNOWTEX (trademark) -O, SNOWTEX OS, SNOWTEX-OL, manufactured by Nissan Chemical Industries, Ltd., and Asahi Denka Kogyo Co., Ltd. Examples thereof include Adelite (trademark) AT-20Q, Clevosol (trademark) 20H12 manufactured by Clariant Japan Co., Ltd., and clebosol 30CAL25.
Examples of basic colloidal silica include silica stabilized by addition of alkali metal ions, ammonium ions, or amines. More specifically, as a commercial product, Snowtex-20 manufactured by Nissan Chemical Industries, Ltd. , SNOWTEX-30, SNOWTEX-C, SNOWTEX-C30, SNOWTEX-CM40, SNOWTEX-N, SNOWTEX-N30, SNOWTEX-K, SNOWTEX-XL, SNOWTEX-YL, SNOWTEX-ZL Adelite AT-20, Adelite AT-30, Adelite AT-20N, Adelite AT-30N, Adelite AT-20A, Adelite AT-, manufactured by Asahi Denka Kogyo Co., Ltd., such as Snowtex PS-M and Snowtex PS-L 30A, Adelite AT-40, Adelite A Such as -50, 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.
As colloidal silica using a water-soluble solvent as a dispersion medium, commercially available products include, for example, MA-ST-M (methanol dispersion type having a particle size of 20 to 25 nm), IPA-ST (particle size) manufactured by Nissan Chemical Industries, Ltd. Is 10-15 nm isopropyl alcohol dispersion type), EG-ST (particle size is 10-15 nm ethylene glycol dispersion type), EG-ST-ZL (particle diameter is 70-100 nm ethylene glycol dispersion type), NPC-ST (Ethylene glycol monopropyl ether dispersion type having a particle size of 10 to 15 nm).

  These colloidal silicas are used alone or in combination of two or more. Colloidal silica may contain alumina, sodium aluminate or the like as a minor component. In addition, an inorganic base (such as sodium hydroxide, potassium hydroxide, lithium hydroxide, or ammonia) or an organic base (such as tetramethylammonium) may coexist in the colloidal silica as a stabilizer.

The photocatalyst that is the component (A2) according to this embodiment is a compound that exhibits photocatalytic activity and / or hydrophilicity when irradiated with light. Specific examples of the photocatalyst include, for example, TiO ₂ , ZnO, SrTiO ₃ , BaTiO ₃ , BaTiO ₄ , BaTi ₄ O ₉ , K ₂ NbO ₃ , Nb ₂ O ₅ , Fe ₂ O ₃ , Ta ₂ O ₅ , K _3. Ta ₃ Si ₂ O ₃ , WO ₃ , SnO ₂ , Bi ₂ O ₃ , BiVO ₄ , NiO, Cu ₂ O, RuO ₂ , CeO ₂ , and at least one selected from the group consisting of Ti, Nb, Ta and V Layered oxides having various elements (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-10-244165, etc.) Door can be. Of these photocatalysts, TiO ₂ (titanium oxide) and ZrO ₂ (zirconium oxide) are preferred because they are harmless and have excellent chemical stability. As the titanium oxide, any of anatase type, rutile type and brookite type can be used.

  Examples of forms when the component (A2) is used include powders, dispersions, and sols. The “dispersion liquid” and “sol” as used herein means that the component (A2) 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. It means a state of being dispersed as primary particles and / or secondary particles.

  The particle size of the component (A2) observed in the dispersion or sol may be a number average particle size (a mixture of primary particles and secondary particles, either primary particles or secondary particles). 1 nm to 200 nm, preferably 1 nm to 100 nm, more preferably 3 nm to 80 nm, and still more preferably 5 nm to 50 nm. The number average particle diameter of the component (A2) can contribute to the optical characteristics of the coating film formed using the resulting coating composition. In particular, setting the number average particle diameter to 100 nm or less can greatly improve the transparency of the resulting coating film. In addition, the number average particle diameter (hereinafter, simply referred to as “particle diameter” in some cases) in the present embodiment is a value measured according to the method of Examples described later.

  Content of (A1) component and (A2) component in the coating composition of this embodiment is 85 / 100-99 / 100 by the mass ratio of (A1) / ((A1) + (A2)) as above-mentioned. It is preferably 88/100 to 99/100, more preferably 93/100 to 99/100. The component (A2) has a refractive index higher than that of the component (A1) and relatively easily causes secondary aggregation. Therefore, by setting (A1) / ((A1) + (A2)) to 88/100 or more, the coating is performed. The transparency of the film can be increased, the haze value can be suppressed, and the reflectance can be increased. In addition, although the refractive index of the component (A1) is significantly different from that of the component (A2), the refractive index of the coating film can be changed by setting (A1) / ((A1) + (A2)) to 88/100 or more. Suppresses and enables easy coating design. On the other hand, by setting (A1) / ((A1) + (A2)) to 99/100 or less, the present inventors can maintain a long-term hydrophilic maintenance performance by colloidal silica and prevent a decrease in hydrophilicity. Found. Although this cause is not clarified in detail, it suggests that a very small amount of the photocatalyst contributes to the hydrophilicity maintaining performance of colloidal silica. In the conventional photocatalyst technology, when titanium oxide, which is one type of photocatalyst, is used in the presence of silica, it has been reported that if the amount of silica is large, the hydrophilicity improvement rate after light irradiation increases. It is considered that a relatively large amount of titanium oxide is required to exhibit practical antifouling properties.

  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.

  In addition to the components (A1) and (A2), as the metal oxide contained in the coating composition of the present embodiment, a conductive metal oxide is used as necessary from the viewpoint of developing antistatic performance and the like. Can do. Examples of such conductive metal oxides include tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), tin oxide, and zinc oxide. From the viewpoint of interaction with the component (B), for example, aluminum oxide, antimony oxide, indium oxide, tin oxide, zirconium oxide, lead oxide, iron oxide, calcium silicate, magnesium oxide, niobium oxide, cerium oxide are used in combination. You can also

  The polymer emulsion particles of component (B) are at least one selected from the group consisting of component (b1): hydrolyzable silicon compound and component (b2): hydroxyl group, carboxyl group, amide group, amino group and ether group. A polymer obtained by polymerizing the component (b1) and the component (b2) in a polymerization stock solution containing a vinyl monomer having a functional group of (b3): an emulsifier and (b4) component: water. Emulsion particles. As the component (B) thus obtained, it is preferable to use a compound in which a hydroxyl group derived from the component (b1) and a polymerization product of the component (b2) are combined by hydrogen bonding or the like.

(B1) As a component, the compound represented by following General formula (4), its condensation product, and a silane coupling agent can be illustrated.
SiW _x R _y (4)
Here, 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. At least one group selected from the group consisting of groups; 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 alkyl group having 1 to 20 carbon atoms or 1 carbon atom. And at least one hydrocarbon group selected from the group consisting of an aryl group having 6 to 20 carbon atoms substituted with an alkoxy group of -20 or a halogen atom. x is an integer from 1 to 4, and y is an integer from 0 to 3. Also, x + y = 4.
The silane coupling agent means a silane derivative in which a functional group having reactivity with an organic substance such as a vinyl polymerizable group, an epoxy group, an amino group, a methacryl group, a mercapto group, or an isocyanate group exists in the molecule.

  Specific examples of the compound represented by the formula (4) include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane; Methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, n-butyltrimethoxysilane N-butyltriethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, vinyltrimethoxysilane, vinyltri Toxisilane, allyltrimethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3,3,3-tri Fluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2-hydroxyethyltriethoxysilane 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, -Mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltri Ethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) Atacyloxypropyltriethoxysilane, 3- (meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysilane, 3-ureidopropyltrimethoxysila , Trialkoxysilanes such as 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-hexyldimethoxy Silane, di-n-hexyldiethoxysilane, di-n-heptyldimethoxysilane, di-n-heptyldiethoxysilane, di-n-octyldimethoxysilane, di-n-octyldiethoxysilane, di-n-cyclohexyl The Dialkoxysilanes such as toxisilane, di-n-cyclohexyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane; monoalkoxysilanes such as trimethylmethoxysilane and trimethylethoxysilane There can be mentioned. Moreover, these are used individually by 1 type 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, the component (b1) may contain a silane coupling agent having a thiol group, or the following component (b1-1), that is, the component (b1-1): a hydrolyzable silicon compound having a vinyl polymerizable group. . When these are used as the component (b1), the resulting coating film has good long-term antifouling properties, 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, 3- (meth) acryloyloxypropylmethyldimethoxysilane, 3 -(Meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxypropyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, 2-trimethoxysilylethyl vinyl ether, etc. Examples thereof include a silane coupling agent 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 component (b1) described above, the polymerization product of the component (b1) and the component (b2) described later are used. The polymerization product can be complexed by chemical bonding.
Examples of the “vinyl polymerizable group” in the component (b1-1) include a vinyl group and an allyl group, and among them, a 3- (meth) acryloxypropyl group is preferable.

  The component (b1) may contain the following component (b1-2), that is, the component (b1-2): cyclic siloxane oligomer. When the said (b1-2) component is used, the softness | flexibility of the coating film obtained becomes more favorable and is suitable.

As a cyclic siloxane oligomer, the compound represented by following General formula (5) can be illustrated.
_{(R '2 SiO) m (} 5)
Here, 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 carbon number. It shows at least one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms substituted with a halogen atom. m is an integer, and 2 ≦ m ≦ 20.
Of these, cyclic dimethylsiloxane oligomers such as octamethylcyclotetrasiloxane are preferred from the viewpoint of reactivity.

  In addition, when a condensation product is used as (b1) component, the polystyrene conversion weight average molecular weight (by GPC method) of the condensation product is preferably 200 to 5,000, more preferably 300 to 1,000.

  In the coating composition of the present embodiment, the mass ratio ((b1) / (B)) of the content of the component (b1) to the content of the component (B) is preferably 0.01 from the viewpoint of polymerization stability. / 100 to 80/100, more preferably 0.1 / 100 to 70/100.

The mass ratio ((b1-1) / (B)) of the content of the component (b1-1) to the content of the component (B) is preferably 0.01 / 100 to 20 / from the viewpoint of polymerization stability. 100, more preferably 0.5 / 100 to 10/100.
The mass ratio of the content of the component (b1-1) to the content of the component (b2) ((b1-1) / (b2)) is preferably 0.1 / 100 to 100 / from the viewpoint of polymerization stability. 100, more preferably 0.5 / 100 to 50/100.

The mass ratio ((b1-2) / (B)) (mass ratio) of the content of the component (b1-2) to the content of the component (B) is preferably 0.01 / 100 from the viewpoint of hydrophilicity. -20/100, more preferably 0.5 / 100 to 5/100.
The mass ratio of the content of the component (b1-2) to the content of the component (b2) ((b1-2) / (b2)) is preferably 0.5 / 100 to 50 / from the viewpoint of polymerization stability. 100, more preferably 1.0 / 100 to 20/100.

  Specific examples of the hydroxyl group-containing vinyl monomer mentioned as the component (b2) include various types such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate. Hydroxyalkyl (meth) acrylates; various hydroxyl group-containing vinyl ethers such as 2-hydroxyethyl vinyl ether or 4-hydroxybutyl vinyl ether; various hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether; represented by polyethylene glycol Polyoxyalkylene glycol monoesters obtained from various polyether polyols and various unsaturated carboxylic acids typified by (meth) acrylic acid; the above-mentioned various hydroxyl group-containing monomers and ε- Adducts with various lactones represented by prolactone; Adducts with various epoxy group-containing unsaturated monomers represented by glycidyl (meth) acrylate and various acids represented by acetic acid; ) Adducts of various unsaturated carboxylic acids typified by acrylic acid and various monoepoxy compounds other than epoxides of α-olefins typified by “Cardura E” (trade name of Shell, Netherlands) It is done.

  Specific examples of the carboxyl group-containing vinyl monomer mentioned as the component (b2) include various kinds such as (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, crotonic acid, itaconic acid, maleic acid or fumaric acid. Unsaturated carboxylic acids such as monomethyl itaconate, mono-n-butyl itaconate, monomethyl maleate, mono-n-butyl maleate, monomethyl fumarate, mono-n-butyl fumarate and saturated Monoesters with monohydric alcohols (half esters); Monovinyl esters of various saturated dicarboxylic acids such as monovinyl adipate or monovinyl succinate; succinic anhydride, glutaric anhydride, phthalic anhydride or trimellitic anhydride Various saturated polycarboxylic acid anhydrides such as acids Addition reaction products of various hydroxyl group-containing vinyl monomers described above; the monomers obtained by addition reaction of the above various carboxyl group-containing monomers of the lactones and the like.

  Specific examples of the amino group-containing vinyl monomer mentioned as the component (b2) include 2-dimethylaminoethyl (meth) acrylate, 2-diethylaminoethyl (meth) acrylate, 2-di-n-propylaminoethyl (meth) ) Acrylate, 3-dimethylaminopropyl (meth) acrylate, 4-dimethylaminobutyl (meth) acrylate or various tertiary amino group-containing (meth) acrylic such as N- [2- (meth) acryloyloxy] ethylmorpholine Acid esters; various tertiary amino group-containing aromatic vinyl monomers such as vinylpyridine, N-vinylcarbazole, N-vinylquinoline; N- (2-dimethylamino) ethyl (meth) acrylamide, N -(2-diethylamino) ethyl (meth) acrylamide, N- (2-di n-propylamino) ethyl (meth) acrylamide, N- (3-dimethylamino) propyl (meth) acrylamide, N- (4-dimethylamino) butyl (meth) acrylamide or N- [2- (meth) acrylamide] ethyl Various tertiary amino group-containing (meth) acrylamides such as morpholine; N- (2-dimethylamino) ethylcrotonamide, N- (2-diethylamino) ethylcrotonamide, N- (2-di-n) Various tertiary amino group-containing crotonic acid amides such as -propylamino) ethylcrotonic acid amide, N- (3-dimethylamino) propylcrotonic acid amide or N- (4-dimethylamino) butylcrotonic acid amide; 2 -Dimethylaminoethyl vinyl ether, 2-diethylaminoethyl vinyl ether Le, various tertiary amino group-containing vinyl ethers such as 3-dimethylamino-propyl vinyl ether or 4-dimethylamino-butyl vinyl ether.

  Specific examples of the ether group-containing vinyl monomer (b2) include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene higher fatty acid ester, polyoxyethylene-polyoxypropylene block copolymer Examples thereof include vinyl monomers such as vinyl ethers, allyl ethers or (meth) acrylic acid esters having various polyether chains such as coalesced in the side chain. More specifically, BLEMMER PE-90, PE-200, PE-350, PME-100, PME-200, PME-400, AE-350 (above, trade name 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, trade name manufactured by Nippon Emulsifier Co., Ltd.) It is done. Here, the number of oxyethylene units in the polyoxyethylene chain is preferably 2 to 30. If it is less than 2, the flexibility of the coating film tends to be insufficient, and if it exceeds 30, the coating film becomes soft and tends to be inferior in blocking resistance.

Specific examples of the amide group-containing vinyl monomer mentioned as the component (b2) include, for example, 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-acryloylhexahi Loazepine, N-acryloylmorpholine, N-methacryloylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, N, N′-methylenebisacrylamide, N, N′-methylenebismethacrylamide, N-vinylacetamide, diacetone acrylamide, Examples include diacetone methacrylamide, N-methylol acrylamide, and N-methylol methacrylamide.
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.

  As the component (b2), it is preferable to use a vinyl monomer having a secondary and / or tertiary amide group from the viewpoint of further improving the hydrogen bondability with other components.

In the coating composition of this embodiment, the mass ratio ((b2) / (B)) of the content of the component (b2) to the content of the component (B) is preferably 0.1 from the viewpoint of polymerization stability. / 1 to 0.5 / 1, more preferably 0.2 / 1 to 0.4 / 1.
Further, the mass ratio of the content of the component (b2) to the content of the component (A1) ((b2) / (A1)) is preferably from the viewpoint of hydrogen bondability with the component (A1) and blending stability. 0.1 / 1 to 1/1, more preferably 0.2 / 1 to 0.7 / 1.

  Examples of component (b3) include acidic emulsifiers such as alkylbenzene sulfonic acids, alkyl sulfonic acids, alkyl sulfosuccinic acids, polyoxyethylene alkyl sulfuric acids, polyoxyethylene alkyl aryl sulfuric acids, polyoxyethylene distyryl phenyl ether sulfonic acids, and acidic emulsifiers. Anionic surfactants such as alkali metal (Li, Na, K, etc.) salts, acidic emulsifiers, fatty acid soaps; quaternary ammonium salts such as alkyltrimethylammonium bromide, alkylpyridinium bromide, imidazolinium laurate, Pyridinium salt, imidazolinium salt type cationic surfactant; polyoxyethylene alkyl aryl ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethyleneoxypropylene block Polymers, nonionic surface active agents such as polyoxyethylene distyryl phenyl ether. These are used singly or in combination of two or more.

As the component (b3), a reaction having a radical polymerizable double bond from the viewpoint of improving the water dispersion stability of the obtained component (B) and improving the long-term antifouling property of the obtained coating film. It is preferable to use a functional emulsifier.
More specifically, the reactive emulsifier includes a vinyl monomer having a sulfonic acid group or a sulfonate group, a vinyl monomer having a sulfate group, and nonions such as alkali metal salts, ammonium salts, and polyoxyethylene thereof. And vinyl monomers having a group, and vinyl monomers 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, and a vinyl sulfonate compound having a vinyl group to which a substituent is bonded, such as an ammonium salt, a sodium salt or a potassium salt of a sulfonic acid group.

  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 Kasei Co., Ltd.), Latemuru S-120, S-180A or S-180 (trade name) (manufactured by Kao Corporation) and the like can be mentioned. .

  A 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 by a substituent such as 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, etc.) , Manufactured by Daiichi Pharmaceutical Industry Co., Ltd.).

  The amount of 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 component (B) from the viewpoint of polymerization stability.

  The component (B) is a weight obtained by polymerizing the component (b1) and the component (b2) in the polymerization stock solution containing the components (b1) to (b3) and the component (b4) (that is, water). Combined emulsion particles. The amount of 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, another vinyl monomer copolymerizable with the following component (b5), ie, component (b5): component (b2), can be mixed in the polymerization stock solution. The use of such a 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, hydrolyzable silicon compound as component (b1) From the viewpoint of controlling the compatibility with the polymerization product, etc.).

  As the component (b5), for example, acrylic ester, methacrylic ester, aromatic vinyl compound, vinyl cyanide, epoxy group-containing vinyl monomer, carbonyl group-containing vinyl monomer, anionic vinyl monomer And monomers containing functional groups such as the body.

  (B5) As a ratio for which a component accounts in all the vinyl monomers, Preferably it is 0.001-30 mass%, More preferably, it is the range of 0.05-10 mass%. Use of component (b5) in this range means that glass transition temperature, molecular weight, hydrogen bonding force, polarity, dispersion stability, weather resistance, compatibility with polymerized product of hydrolyzable silicon compound as component (b1) From the viewpoint of controlling the above and the like.

  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. And thiocarboxylic acids or their salts or alkyl esters thereof, or polythiols, diisopropylxanthogen disulfide, di (methylenetrimethylolpropane) xanthogen disulfide and thioglycol, and allyl compounds such as dimer of α-methylstyrene.

  The amount of the chain transfer agent used is preferably 0.001 to 30 parts by mass, more preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the total amount of all vinyl monomers. Use of a chain transfer agent in this range is preferred 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 resin, and polyacrylic. Synthetic or natural water-soluble or water-dispersible various water-soluble polymer substances such as acid (salt), polyacrylamide, water-soluble or water-dispersible acrylic resin and the like can be mentioned. These are used singly or in combination of two or more.

  The amount of these dispersion stabilizers to be 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) polymer emulsion particles.

  The polymerization of the polymerization stock solution is preferably carried out in the presence of a polymerization catalyst. Examples of the polymerization catalyst for 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, sulfonic acids such as sulfuric acid and p-toluenesulfonic acid, Acid emulsifiers such as alkylbenzene sulfonic acid, alkyl sulfonic acid, alkyl sulfosuccinic acid, polyoxyethylene alkyl sulfuric acid, polyoxyethylene alkyl aryl sulfuric acid, polyoxyethylene distyryl phenyl ether sulfonic acid, acidic or weakly acidic inorganic salt, phthalic acid Acidic compounds such as phosphoric acid and nitric acid; sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, tetramethylammonium chloride, tetramethylammonium hydroxide, tributylamine, diazabicycloundecene, ethylenedia , Diethylenetriamine, ethanolamines, basic compounds such as γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl) -aminopropyltrimethoxysilane; tin compounds such as dibutyltin octylate and dibutyltin dilaurate Is mentioned. Among them, as a polymerization catalyst for the hydrolyzable silicon compound which is the component (b1), acidic emulsifiers having an action as an emulsifier as well as a polymerization catalyst, particularly alkylbenzenesulfonic acid (dodecylbenzenesulfonic acid having 5 to 30 carbon atoms). Etc.) is preferred.

  As the polymerization catalyst for the component (b2), a radical polymerization catalyst that causes radical polymerization by heat or a reducing substance to cause addition polymerization of a vinyl monomer is suitable. Examples of such radical polymerization catalysts include water-soluble or oil-soluble persulfates, peroxides, and azobis compounds, and these are preferable. More specifically, as a radical polymerization catalyst, for example, potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, 2,2-azobisisobutyrate. Examples include nitrile, 2,2-azobis (2-diaminopropane) hydrochloride, and 2,2-azobis (2,4-dimethylvaleronitrile).

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 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, Rongalite in combination with the radical polymerization catalyst. is there.
In this embodiment, the polymerization of the component (b1) and the polymerization of the component (b2) can be carried out separately, but if carried out at the same time, a micro organic / inorganic composite by hydrogen bonding or the like can be achieved. Therefore, it is preferable.

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.
As a method of emulsion polymerization, for example, the components (b1) and (b2) and, if necessary, the component (b3) as it is or in an emulsified state, are batched or divided, or continuously in a reaction vessel. A method of polymerizing at a reaction temperature of about 30 to 150 ° C. by dropping into the inside and preferably in the presence of a polymerization catalyst, preferably from atmospheric pressure to 10 MPa as necessary. However, if necessary, the polymerization may be carried out at a higher pressure or lower temperature conditions.

In addition, about the mixing | blending of superposition | polymerization stock solution, from a viewpoint of superposition | polymerization stability, each component of (b1)-(b4) so that the last solid content may be 0.1-70 mass%, Preferably it becomes the range of 1-55 mass%. Is preferably blended.
Furthermore, when performing emulsion polymerization, it is preferable to use a seed polymerization method from the viewpoint of appropriately growing or controlling the particle diameter of the component (B) obtained. The seed polymerization method is a method in which emulsion particles (seed particles) are previously present in an aqueous phase for polymerization. The pH in the polymerization system when performing the seed polymerization method is preferably 1.0 to 10.0, and more preferably 1.0 to 6.0. The pH can be adjusted using a pH buffer such as disodium phosphate, borax, sodium bicarbonate, ammonia.

  In addition, as a method for obtaining the component (B), the component (b1) and the component (b2) are present in the presence of a solvent if necessary in the presence of the component (b3) and the component (b4) necessary for polymerizing the component (b1) It is also possible to apply a method in which water is added after the polymerization is performed until the polymerization product becomes an emulsion.

  From the viewpoint of improving the base material adhesion of the coating film formed using the coating composition containing the component (B), the core layer and one or more shells covering the core layer Preferably, it has a core / shell structure with layers. As a method for forming the core / shell structure, multistage emulsion polymerization in which emulsion polymerization is performed in multiple stages is very useful.

  Specifically, the multistage emulsion polymerization is, for example, as the first stage, in the presence of the component (b3) and the component (b4), and at least selected from the group consisting of the component (b1), the component (b2), and the component (b5). One or more components are polymerized to form seed particles, and as a second step, a polymerization stock solution containing components (b1) and (b2), and optionally (b5) components in the presence of the seed particles. Is added for polymerization (two-stage polymerization method). When carrying out multi-stage emulsion polymerization of three or more stages, for example, as a third stage, polymerization may be carried out by adding a polymerization stock solution further containing the component (b1) and the component (b2) and, if necessary, the component (b5). it can. Such a method is also suitable from the viewpoint of polymerization stability.

  When employing the two-stage polymerization method, the mass ratio of the solid content mass (M1) in the polymerization stock solution used in the first stage to the solid content mass (M2) in the polymerization stock solution added in the second stage ( (M1) / (M2)) is preferably 9/1 to 1/9, more preferably 8/2 to 2/8, from the viewpoint of polymerization stability.

  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 particle size is increased by the second stage polymerization. It is preferred to have an increased structure. The volume average particle diameter can be measured in the same manner as the number average particle diameter.

  In the polymer emulsion particles (B) according to this embodiment, in the core layer, the mass ratio of the content of the (b2) component to the content of the (b1) component ((b2) / (b1)) is 0.00. It is preferable that it is 01/1 to 1/1. In the outermost layer of the shell layer, the mass ratio of the content of the component (b2) to the content of the component (b1) ((b2) / (b1)) is 0.1 / 1 to 5/1. Is preferred. In the core layer, when (b2) / (b1) is smaller than 0.01 / 1, the polymerization stability tends to be insufficient, and when it is larger than 1/1, durability and flexibility are hardly sufficient. Become. Further, in the outermost layer of the shell layer, when (b2) / (b1) is smaller than 0.1 / 1, the interaction with the component (A) is small, and when it is larger than 5/1, the interaction is strong. Therefore, it tends to be difficult to obtain sufficient stability.

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

  The glass transition temperature (Tg) of the core layer of the core / shell structure is preferably 0 ° C. or lower. In this case, since the coating composition obtained is excellent in flexibility at room temperature as a physical property of the coating film, it is possible to form a protective member for a solar cell that is less likely to be cracked or the like. In the present embodiment, Tg can be measured with a differential scanning calorimeter (DSC).

The particle size (number average particle size) of the component (B) is 10 nm to 800 nm. By adjusting the particle diameter of the component (B) to such a range and forming the composition in combination with the component (A1) having a particle diameter of 1 nm to 400 nm, the weather resistance and antifouling properties are improved. Moreover, from a viewpoint of the transparency improvement of the coating film obtained, it is suitable that the particle diameter of (B) component is 10 nm-100 nm.
In the coating composition of this embodiment, the mass ratio ((A1) + (A2) / (B)) of the total content of the component (A1) and the component (A2) to the content of the component (B) is 60 / It is 100-480 / 100, Preferably it is 110 / 100-350 / 100, More preferably, it is 150 / 100-300 / 100. A coating composition in which ((A1) + (A2)) / (B) is blended in this range is preferable because a coating film excellent in transparency and hydrophilicity immediately after coating can be realized. Moreover, since such antifouling property tends to last for a long time, it is preferable.

  The ratio ((SA1) / (SB)) of the surface area (SA1) of the component (A1) and the surface area (SB) of the component (B) is preferably in the range of 0.001 to 1000. The surface area of each component can be calculated from the particle diameter, the mass, and the specific gravity of each of the components (A1) and (B), assuming that the particle shape is a true sphere.

  In addition to the above-described components, the coating composition of the present embodiment usually includes additive components that are added and blended in paints and molding resins, for example, light stabilizers, ultraviolet rays, depending on the application and method of use. Absorber, thickener, leveling agent, thixotropic agent, antifoaming agent, freezing stabilizer, matting agent, crosslinking reaction catalyst, pigment, curing catalyst, crosslinking agent, filler, anti-skinning agent, dispersant, wetting Agent, antioxidant, UV absorber, rheology control agent, film forming aid, rust inhibitor, dye, plasticizer, lubricant, reducing agent, preservative, antifungal agent, deodorant, yellowing inhibitor, An antistatic agent, a charge control agent, 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. As an 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 an 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 (A1), the component (A2) and the component (B), or the component (B). It is also possible to coexist when synthesizing.

The coating composition of this embodiment preferably contains a hydrolyzable silicon compound as component (C) for the purpose of improving the strength and antifouling properties of the coating film. As the hydrolyzable silicon-containing compound used as the component (C), the hydrolyzable silicon-containing compound (c1) represented by the following general formula (1) and the hydrolyzable silicon represented by the following general formula (2) The containing compound (c2) can be used.
R ¹ _n SiX _4-n (1)
Here, in formula, R < ¹ > is a hydrogen atom or a C1-C10 alkyl group which may have a halogen group, a hydroxy group, a mercapto group, an amino group, a (meth) acryloyl group, or an epoxy group. , An alkenyl group, an alkynyl group or an aryl group. X represents a hydrolyzable group, and n is an integer of 0 to 3. Here, the hydrolyzable group is a group that generates a hydroxyl group by hydrolysis, and examples thereof include a halogen atom, an alkoxy group, an acyloxy group, an amino group, a phenoxy group, and an oxime group.
X ₃ Si—R ² _n —SiX ₃ (2)
Here, in the formula, X represents a hydrolyzable group, and R ² represents an alkylene group having 1 to 6 carbon atoms or a phenylene group. N is 0 or 1.

  Specific examples of the hydrolyzable silicon compounds (c1) and (c2) include tetramethoxysilane, tetraethoxysilane, tetra (n-propoxy) silane, tetra (i-propoxy) silane, tetra (n-butoxy) silane, Tetra (i-butoxy) silane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, Propyltrimethoxysilane, propyltriethoxysilane, isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxysilane, diethoxysilane, methyldimethoxysilane , 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- Hydroxypropyltriethoxy 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, tetrabutyl Lomosilane, tetrafluorosilane, trichlorosilane, tribromosilane, trifluorosilane, methyltrichlorosilane, methyltribromosilane, methyltrifluorosilane, tetrakis (methylethylketoxime) silane, tris (methylethylketoxime) silane, methyltris (methylethylketoxime) Silane, phenyltris (methylethylketoxime) silane, bis (methylethylketoxime) silane, methylbis (methylethylketoxime) silane, hexamethyldisilazane, hexamethylcyclotrisilazane, bis (dimethylamino) dimethylsilane, bis (diethylamino) dimethylsilane, Examples include 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 thereof include a partial hydrolysis condensate of tetramethoxysilane (for example, trade name “M silicate 51” manufactured by Tama Chemical Industry Co., Ltd., trade name “MSI 51” manufactured by Colcoat Co., Ltd., Mitsubishi Chemical Corporation). ) "MS51", "MS56"), a partially hydrolyzed condensate of tetoethoxysilane (trade names "Silicate 35", "Silicate 45", manufactured by Tama Chemical Industry Co., Ltd., manufactured by Colcoat Co., Ltd.) Trade names “ESI40”, “ESI48”), co-hydrolyzed condensate of tetramethoxysilane and tetraethoxysilane (trade name “FR-3” manufactured by Tama Chemical Industry Co., Ltd.), manufactured by Colcoat Co., Ltd. Trade name "EMSi48").
R ³ — (O—Si (OR ³ ) ₂ ) _n —OR ³ (3)
Here, in the formula, R ³ represents an alkyl group having 1 to 6 carbon atoms. n is an integer of 2-8.

  The said hydrolysable silicon compound which is (C) component is used individually by 1 type or in combination of 2 or more types.

  In the coating composition of the present embodiment, the mass ratio of the content of the component (C) to the content of the component (A1) ((C) / (A1)) is preferably 0.2 / 100 to 300 / 100, more preferably 1/100 to 100/100. When (C) / (A1) is smaller than 0.2 / 100, the contact angle tends to be insufficiently lowered under high temperature conditions. When (C) / (A1) exceeds 300/100, the coating angle tends to be insufficient. The film tends to become brittle.

  The coating composition of the present embodiment is not particularly limited, but can be prepared in a state of being dissolved and / or dispersed in water and, if necessary, another solvent.

  As a base material used in the present embodiment, for example, a material whose material is glass or resin is preferably used. From the viewpoint of transparency, weather resistance, and weight reduction, the material constituting the substrate is at least selected from the group consisting of glass, acrylic resin, polycarbonate resin, cyclic olefin resin, polyethylene terephthalate resin, and ethylene-fluoroethylene copolymer. One kind of material or a composite material thereof is preferable. A weathering agent or the like may be further kneaded into the acrylic resin, polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalate resin, or ethylene-fluoroethylene copolymer for the purpose of imparting weather resistance.

  When the coating film according to the present embodiment is used as a protective member for a solar power generation reflecting mirror, for example, as a reflecting mirror as a base material, a metal plating or metal coating on a substrate such as glass, ceramic and plastic (resin) A flat or curved surface having a sunlight reflecting function, including a reflective layer formed by applying (for example, coating by vapor deposition), or bonding the substrate and a metal plate or metal foil together with a transparent adhesive A reflective substrate can be used. 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.

  The film thickness of the transparent layer is preferably 50 μm to 10 mm, and the film thickness may be selected from the viewpoints of the material, required mechanical strength and transparency. Further, as a method for forming the transparent layer, when the material of the transparent layer is glass, a known glass molding method such as a floating molding method is used. When the transparent layer is a resin, for example, a melt casting method or an extrusion sheeting method is used. A known resin molding method is used. In the present embodiment, “transparent” means 10% or less as a Haze value measured according to ASTM D-1003.

  In addition, for example, the member for an energy conversion device of the present embodiment is obtained by applying the above-described coating composition dispersed in a solvent such as water (simply abbreviated as “water dispersion”) onto a substrate. It is formed by drying. Here, the solid content concentration of the aqueous dispersion is preferably 0.01 to 60% by mass, more preferably 1 to 40% by mass. The viscosity of the aqueous dispersion is preferably 0.1 to 100,000 mPa · s, more preferably 1 to 10,000 mPa · s at 20 ° C. Furthermore, as a method for applying the coating composition to the substrate, for example, spraying method, flow coating method, roll coating method, bar coating method, brush coating method, dip coating method, spin coating method, screen printing method, casting method , Gravure printing method and flexographic printing method. In addition, the member for energy conversion devices of this embodiment provided by laminating the base material and the coating film is preferably, for example, after drying the coating film on the base material, and preferably by heat treatment or ultraviolet irradiation at 100 ° C. or less. Etc. can also be obtained.

  Thus, the coating film with which the member for energy converters of this embodiment obtained was equipped with the said (A1) component, (A2) component, (B) component, and the said (C) component as needed. And the additive component that can remain as a solid content.

  The thickness of the coating film is preferably 0.05 to 100 μm, more preferably 0.1 to 10 μm. From the viewpoint of transparency, the thickness is preferably 100 μm or less, and in order to more effectively express functions such as weather resistance and antifouling properties, the thickness is preferably 0.05 μm or more.

  The refractive index of the coating film is preferably 1.3 to 1.5. When used as a protective member for a light reflecting mirror that places importance on reflectance, the coating film preferably has a refractive index of 1.45 to 1.5. When applied to a transparent member that places importance on light transmittance, the refractive index is 1. It is preferable that it is .3-1.45. In this embodiment, since the refractive index of the component (A1) and the component (A2) are greatly different, in order to control the refractive index within the above range in a composition having a high content of the component (A1), the component (A2) Of course, it is also useful to disperse the component (A2) as uniformly as possible in the coating film.

  In the present embodiment, the “coating film” is not necessarily a continuous film, and may be a discontinuous film, an island-shaped dispersion film, or the like.

  The coating composition of the present embodiment is suitably used as a functional film provided in a member for an energy conversion device such as a protection member for a solar cell or a protection member for a light reflecting mirror by forming a coating film as described above. Can do. The haze value of the coating film is preferably 10% or less. When the haze value is 10% or less, it is more useful as a functional film provided in the energy conversion device member. The “haze value” here is measured according to the method described in the following examples.

  When a coating film is used as a protective member for a light reflecting mirror, the reflector device of the present embodiment includes the member and a support that supports the energy conversion device member from the side opposite to the coating film. The reflector device can be suitably used in a solar thermal power generation system including a device that uses sunlight collected by the reflector device as a heat source and converts the sunlight into electric energy. That is, the solar thermal power generation system of this embodiment includes the above-described reflector device that condenses sunlight, and a device that converts the heat of the collected sunlight into electrical energy. The reflector device and the solar thermal power generation system of these embodiments are not particularly limited in their aspects except for having the above configuration, and configurations other than the above configuration may be conventionally known.

  According to the present embodiment, a water-based coating composition that has high transparency, exhibits high hydrophilicity immediately after coating, and can form the coating film without baking at a high temperature together with a coating film that can maintain the high hydrophilicity for a long period of time. And the member for energy converters provided with the coating film obtained from the coating composition, the reflector apparatus provided with the member for energy converters, and the solar thermal power generation system provided with the reflector apparatus can be provided.

  EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to a following example, unless the summary is exceeded. Various physical properties were evaluated by the following methods.

1. Number average particle size Diluted by adding a solvent as appropriate so that the solid content in the sample is 1 to 20% by mass, and included in the sample using a wet particle size analyzer (Microtrac UPA-9230, manufactured by Nihon Koki Co., Ltd.) The number average particle size of the particles to be measured was measured.

2. Initial contact angle After placing a drop of deionized water on the surface of the coating film and leaving it at 23 ° C. for 1 minute, using a contact angle measurement device (Kyowa Interface Science, CA-X150 contact angle meter), The contact angle of the water droplet was measured.

3. Initial haze Using a turbidimeter (trade name “NDH2000”, manufactured by Nippon Denshoku Industries Co., Ltd., Japan), in accordance with JIS-K7105, an energy conversion device member and a coating film that are a laminate of a base material and a coating film The haze value was measured (initial haze value).

4). Film thickness and refractive index The film thickness and refractive index (wavelength: 633 nm) of the coating film laminated | stacked on the base material were measured using the film thickness meter (made by Otsuka Electronics, brand name "FE-3000").

5. Appearance of coating film The appearance of the coating film was observed with a microscope (manufactured by Keyence Corporation) at a magnification of 100 times. The results were evaluated as follows.
○: There are almost no microcracks.
Δ: Many microcracks.
X: Film cannot be formed.

6). Contact angle after heating and standing After the coating film laminated on the substrate was allowed to stand at 70 ° C. for 10 days, a drop of deionized water was placed on the surface of the coating film and left at 23 ° C. for 1 minute. The contact angle of the water droplet was measured using a contact angle measuring device (CA-X150 type contact angle meter, manufactured by Kyowa Interface Science, Japan).

7). Contact angle after weather resistance test For the coating film laminated on the base material, a xenon weatherometer (manufactured by Suga Test, cycle condition: xenon lamp illuminance 60 W / m ² , BPT 63 ° C., 50% RH, 102 minutes, The light resistance test was carried out for 2500 hours under rainfall, 30 ° C., 95% RH, 18 minutes). Next, after placing a drop of deionized water on the surface of the coating film and leaving it at 23 ° C. for 1 minute, using a contact angle measuring device (Kyowa Interface Science, CA-X150 contact angle meter), the water drop The contact angle of was measured.

[Production Example 1]
<Synthesis of Polymer Emulsion Particle (B-1) Water Dispersion>
Into a reaction vessel having a reflux condenser, a dropping tank, a thermometer and a stirring device, 1600 g of ion-exchanged water and 6 g of dodecylbenzenesulfonic acid were added, and then the temperature was heated to 80 ° C. with stirring. To this, a mixed solution of 185 g of dimethyldimethoxysilane and 117 g of phenyltrimethoxysilane was dropped over about 2 hours while keeping the temperature in the reaction vessel at 80 ° C., and then the temperature in the reaction vessel was raised to 80 ° C. Stirring was continued for about 1 hour in the maintained state. Next, a mixed solution of 86 g of butyl acrylate, 133 g of phenyltrimethoxysilane and 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 1900 g of ion-exchanged water were mixed in a state where the temperature in the reaction vessel was maintained at 80 ° C. It was dripped simultaneously over 2 hours. Further, stirring was continued for about 2 hours while maintaining the temperature in the reaction vessel at 80 ° C., and then the liquid was cooled to room temperature and filtered through a 100-mesh wire mesh, and then the solid content in the liquid was removed with ion-exchanged water. The aqueous dispersion of polymer emulsion particles having a number average particle diameter of 70 nm as component (B) was obtained by adjusting to 10.0% by mass.

( Reference Examples 1-3)
Colloidal silica (manufactured by Nissan Chemical Industries, Ltd., trade name “Snowtex-OS” (component (A1)) is diluted with water to form a dispersion having a solid content of 10% by mass (number average particle diameter of particles 8 nm). A photocatalyst (manufactured by Ishihara Sangyo Co., Ltd., trade name “TSK-5”, number average particle diameter 10 nm, silica-coated titanium oxide hydrosol) (component (A2)) and the weight synthesized in Production Example 1 was prepared. An aqueous dispersion of coalesced emulsion particles was blended in the composition shown in Table 1 to obtain a coating composition, and the obtained coating composition was white plate glass (thickness 2 mm, 6 × 6 cm square) so as to have a film thickness of 250 nm. After apply | coating by spin-coating on it, it was made to dry at 70 degreeC for 30 minute (s), and the member for energy converters provided with the white board glass which is a base material, and the coating film provided on it was obtained.

(Examples 1-2 )
Furthermore, as component (C), tetraethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBE-04”) is blended, and the component (A2) is a photocatalyst (manufactured by Ishihara Sangyo Co., Ltd., trade name “MPT-422”, A coating composition was obtained in the same manner as in Reference Example 1 except that the composition shown in Table 1 was used instead of (number average particle size 30 nm, titanium oxide hydrosol). An energy conversion device member was obtained in the same manner as in Reference Example 1 except that the coating composition was used.

(Comparative Example 1)
A coating composition was obtained in the same manner as in Reference Example 1, except that the composition shown in Table 1 was used. An energy conversion device member was obtained in the same manner as in Reference Example 1 except that the coating composition was used.

  The coating film using the coating composition of the present invention has good transparency, exhibits high hydrophilicity immediately after coating, can maintain the high hydrophilicity for a long period of time, and forms the coating film on a substrate. Since baking is unnecessary, it can be used as a solar cell protective member, a solar power generation light reflecting mirror, or the like having good sunlight permeability and light collecting properties.

Claims (13)

A substrate;
(A1) component: colloidal silica having a particle size of 1 nm to 400 nm, (A2) component: a photocatalyst having a particle size of 1 nm to 200 nm, and (B) component: polymer emulsion particles having a particle size of 10 nm to 800 nm. A coating composition obtained by applying the coating composition on the substrate and drying at 100 ° C. or lower;
A member for an energy conversion device comprising the coating film as a protective member for a light reflecting mirror ,
The component (B) comprises at least one functional group selected from the group consisting of (b1) component: hydrolyzable silicon compound and (b2) component: hydroxyl group, carboxyl group, amide group, amino group and ether group. A polymer emulsion obtained by polymerizing the component (b1) and the component (b2) in a polymerization stock solution containing a vinyl monomer having, (b3) component: emulsifier, and (b4) component: water. Particles,
The mass ratio of the total content of the component (A1) and the component (A2) to the content of the component (B) is 60/100 to 480/100, and the component (A1) relative to the total content The mass ratio of the content of is 85/100 to 99/100,
The coating composition, (C) component: further seen contains tetraethoxysilane,
The member for energy converters whose mass ratio of content of the said (C) component with respect to content of the said (A1) component is 1 / 100-100 / 100 . The member for energy converters of Claim 1 whose mass ratio of content of the said (A1) component with respect to the said total content is 95.3 / 100-98.5 / 100. The member for energy converters of Claim 1 or 2 whose mass ratio of content of the said (b2) component with respect to content of the said (B) component is 0.1 / 1-0.5 / 1. The energy conversion device according to any one of claims 1 to 3, wherein a mass ratio of the content of the component (b2) to the content of the component (A1) is 0.1 / 1 to 1/1 . Member . The energy according to any one of claims 1 to 4, wherein the component (B) has a core / shell structure including a core layer and one or more shell layers covering the core layer. Conversion device member . In the core layer, the mass ratio of the content of the (b2) component to the content of the (b1) component is 0.01 / 1 to 1/1, and in the outermost layer of the shell layer, the (b1) The member for energy converters of Claim 5 whose mass ratio of content of said (b2) component with respect to content of a component is 0.1 / 1-5/1. The component (B) is a polymer emulsion particle obtained by polymerizing the component (b1) and the component (b2) in the polymerization stock solution containing the seed particles that form the core layer, and the seed particles Is obtained by polymerizing at least one component selected from the group consisting of the component (b1), the component (b2), and (b5) another vinyl monomer copolymerizable with the component (b2). The member for energy conversion devices according to claim 5 or 6 which is particles made. The energy conversion device member according to any one of claims 1 to 7, wherein the component (b2) is a vinyl monomer having a secondary and / or tertiary amide group. The member for energy converters as described in any one of Claims 1-8 whose particle diameters of the said (B) component are 10-100 nm. The member for energy converters as described in any one of Claims 1-9 whose refractive index of the said coating film is 1.3-1.5. The haze value of the coating film is 10% or less, the energy conversion device member according to claim 10, wherein. A member for energy conversion apparatus according to any one of claims 1 to 11, a reflector apparatus provided with a support for supporting the opposite side of the member for the energy conversion device and the coating film. A solar thermal power generation system comprising: the reflector device according to claim 12 that condenses sunlight; and a device that converts heat of the condensed sunlight into electric energy.