JP2004359902A - Photocatalytic coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a one-coat photocatalytic coating material with a simple constitution without damaging the design performance of a base material and capable of protecting the base material from a photocatalytic reaction. <P>SOLUTION: This photocatalytic coating material is coated on an organic base material or a surface of an organic coating material. The coated film transmits ≥50 % of 500 nm wave length of light of visible light and blocks ≥80 % of 320 nm wave length of light of UV light. Thus, the coated film ensures the design performance of the base material by the visible light transmission through the film and protects the base material by blocking the UV light from photocatalytic degradation. The photocatalytic coating material comprises a partially hydrolyzed organosiloxane represented by an average composition formula: R<SP>2</SP><SB>a</SB>SiO<SB>b</SB>(OR<SP>1</SP>)<SB>c</SB>(OH)<SB>d</SB>and having a weight average molecular weight of 600-5,000 in terms of polystyrene. By adjusting a coated film thickness, a particle size and content of the photocatalyst, the UV light blocking property, a light scattering particle and a type of R<SP>2</SP>, etc., the one-coat photocatalytic coating material with superior weather resistance and maintenance of the design performance is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００９８】
（調製例Ｂ−１）攪拌機、加温ジャケット、コンデンサー、滴下ロート、窒素ガス導入・排出孔及び温度計を取り付けたフラスコに、ｎ−ブチルメタクリレート（ＢＭＡ）５．６９ｇ（４０ｍｍｏｌ）、トリメトキシシリルプロピルメタクリレート（ＳＭＡ）１．２４ｇ（５ｍｍｏｌ）、グリシジルメタクリレート（ＧＭＡ）０．７１ｇ（５ｍｍｏｌ）、さらに連鎖移動剤としてγ−メルカプトプロピルトリメトキシシラン０．７８４ｇ（４ｍｍｏｌ）をトルエン８．４９ｇに溶解した反応液に、窒素気流下、アゾビスイソブチロニトリル０．０２５ｇ（０．１５ｍｍｏｌ）をトルエン３ｇに溶解したものを滴下し、７０℃で２時間反応させた。重量平均分子量１，０００の重合物が得られた。ここで得たアクリル樹脂溶液をＢ−１と称する。なお、分子量はゲルパーミエーションクロマトグラフィーにより（測定機種：ＨＬＣ−８０２ＵＲ、東ソー株式会社製）、標準ポリスチレン換算値を求めた。以後の分子量も同様の方法で測定した。Ｂ−１の調製条件を表２に示す。
【００９９】
【表２】

【０１００】
（調製例Ｄ−１）攪拌機、加温ジャケット、コンデンサー、滴下ロート及び温度計を取り付けたフラスコにメチルトリイソプロポキシシラン２２０ｇ（１ｍｏｌ）のトルエン１５０ｇの溶液を仕込み、１％塩酸水溶液１０８ｇを上記混合液に２０分で滴下してメチルトリイソプロポキシシランを加水分解した。滴下４０分後に攪拌を止め、二層に分離した少量の塩酸を含んだ下層の水・イソプロピルアルコールの混合液を分液し、後に残ったトルエンの樹脂溶液中に残存する塩酸を水洗で除去し、さらにトルエンを減圧除去し、イソプロピルアルコールで希釈して、重量平均分子量約２，０００のシラノール基含有オルガノポリシロキサンのイソプロピルアルコール４０％溶液を得た。これをＤ−１と称する。
【０１０１】
（調合例１）以下の表１に示す各成分・分量を混合、攪拌することで光触媒塗料１を作製した。
【０１０２】
【表３】

【０１０３】
＜実施例１＞
５センチ×１７センチのスレート板の表面に、神東塗料（株）製「浸透性エポキシシーラー」をローラーで１５０ｇ／ｍ^２の塗布量になるように塗布し、これを室温（約２３℃）で２４時間乾燥させ、この上に同社製「シントップＵＰ白」をローラーで２００ｇ／ｍ^２の塗装量となるように塗布し、室温（約２３℃）で２４時間乾燥させることにより、塗布硬化被膜を形成した。
【０１０４】
次いで、上記調合例１で調合した光触媒塗料１をスプレーにて１０ｇ／ｍ^２となるように塗装した。この塗膜の物性は、石英板上に同時に作製した塗膜の物性を調べた結果によると、膜厚は２μｍ、波長５００ｎｍの光透過率８４％、波長３２０ｎｍの紫外線遮断率９９％であった。このようにして基材に光触媒塗料１を塗装した塗装品は、サンシャインウエザオメーター（耐候性試験機）４０００時間試験後において、塗膜の外観に異常がなく、また、碁盤目テープ剥離試験による密着性試験の結果も良好であった。
【０１０５】
＜実施例２＞
表３に示した調合例１の成分に対し、イソプロピルアルコールに分散した酸化亜鉛を、固形分比で樹脂：酸化チタン：酸化亜鉛＝７０：１０：２０となるように加えて調製し、このようにして光触媒塗料を得た以外は実施例１と同様にして基材に光触媒塗料を塗装した塗装品を作成した。前記同様に、石英板上に同時に作製した塗膜の物性を調べた結果によると、膜厚は２μｍ、波長５００ｎｍの光透過率８７％、波長３２０ｎｍの紫外線遮断率９８％であった。この塗装品は、サンシャインウエザオメーター（耐候性試験機）４０００時間試験後において、塗膜の外観に異常がなく、また、碁盤目テープ剥離試験による密着性試験の結果も良好であった。
【０１０６】
＜実施例３＞
表３に示した調合例１の成分に対し、イソプロピルアルコールに分散した酸化セリウムを、固形分比で樹脂：酸化チタン：酸化セリウム＝７０：１０：２０となるように加えて調製し、このようにして光触媒塗料を得た以外は実施例１と同様にして基材に光触媒塗料を塗装した塗装品を作成した。前記同様に、石英板上に同時に作製した塗膜の物性を調べた結果によると、膜厚は２μｍ、波長５００ｎｍの光透過率８９％、波長３２０ｎｍの紫外線遮断率９５％であった。この塗装品は、サンシャインウエザオメーター（耐候性試験機）４０００時間試験後において、塗膜の外観に異常がなく、また、碁盤目テープ剥離試験による密着性試験の結果も良好であった。
【０１０７】
＜実施例４＞
表３に示した調合例１の成分に対し、イソプロピルアルコールに分散した酸化亜鉛及び粒径３００ｎｍのシリカを、固形分比で樹脂：酸化チタン：酸化亜鉛：シリカ＝６８：１０：２０：２となるように加えて調製し、このようにして光触媒塗料を得た以外は実施例１と同様にして基材に光触媒塗料を塗装した塗装品を作成した。前記同様に、石英板上に同時に作製した塗膜の物性を調べた結果によると、膜厚は２μｍ、波長５００ｎｍの光透過率７０％、波長３２０ｎｍの紫外線遮断率９９％であった。この塗装品は、サンシャインウエザオメーター（耐候性試験機）４０００時間試験後において、塗膜の外観に異常がなく、また、碁盤目テープ剥離試験による密着性試験の結果も良好であった。
【０１０８】
＜比較例１＞
松下電工（株）製光触媒塗料フレッセラＰ−Ｓ１０００を、実施例１で作製した塗布硬化被膜付きの基材（スレート板にシーラーと白色塗料を塗装したもの）に、スプレーで５ｇ／ｍ^２となるように塗装した。なお、この塗料は、通常、有機塗料上に塗装する場合は「フレッセラＮＡ」なるプロテクト層（アンダーコート）を用いることが標準仕様である。しかし、比較例１では、比較のためフレッセラＮＡを用いずに直接塗装した。比較例として作製した塗装品は、サンシャインウエザオメーター５００時間の試験においてチョーキングを生じた。
【０１０９】
このように、従来の光触媒塗料ではアンダーコートを施さない場合に耐候性が低くなるのに対し、上述の実施例で示したように、本発明の光触媒塗料ではアンダーコートを施さない１コート塗布の場合でも良好な結果が得られることが判った。
【図面の簡単な説明】
【図１】（ａ）は本発明の一実施形態に係る光触媒塗料を塗布した基材の断面図、（ｂ）は前記光触媒塗料を塗布した他の例を示す基材の断面図。
【図２】（ａ）は本発明の一実施形態に係る光触媒塗料による塗膜の波長５００ｎｍの光に対する光透過率のグラフ、（ｂ）は前記光触媒塗料による塗膜の波長３２０ｎｍの光に対する光透過率のグラフ。
【符号の説明】
１ 光触媒塗料
２ 有機基材
３ 有機塗料
４ 基材[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a photocatalyst paint that is a paint containing a photocatalyst, a coated film coated with the photocatalyst paint, and a coated article having the coated film.
[0002]
[Prior art]
Conventionally, many photocatalyst paints obtained by adding a photocatalyst to a paint have been developed. This photocatalytic coating material can impart antifouling performance and air purification performance to the substrate by attaching (painting) to the substrate. The photocatalyst referred to here is a substance that mainly absorbs ultraviolet light contained in sunlight, generates charge separation therein, and generates holes and electrons. The photocatalyst is used as a material that exerts purification / sterilization and antifouling performance by utilizing the fact that these holes and electrons cause the decomposition of dirt components and air pollutants, and that the surface of the photocatalyst becomes hydrophilic.
[0003]
Such a photocatalyst decomposes almost all organic substances other than dirt when irradiated with ultraviolet rays. Therefore, when a photocatalytic paint is applied to the surface of an organic substrate such as plastic or a substrate coated with an organic paint, the organic substrate or the organic paint on the surface of the substrate is decomposed, and as a result, the photocatalytic paint is used. There is a problem that the life of the product is very short. It is essential to solve this problem. As a typical method therefor, before coating the photocatalytic coating, a film (referred to as an undercoat) composed of a component that is not decomposed by the photocatalyst is formed on a base material, and the photocatalytic coating is coated thereon. Is known (for example, see Patent Document 1).
[0004]
As another method, a colored paint is used as a paint to prevent ultraviolet light and visible light from reaching the base material and to prevent the occurrence of a photocatalytic reaction near the base material, thereby protecting the base material from the photocatalytic reaction. A method is known (for example, see Patent Document 2).
[0005]
[Patent Document 1]
Japanese Patent No. 3182107
[Patent Document 2]
JP-A-2002-0697376
[0006]
[Problems to be solved by the invention]
However, there are some problems in the method for protecting a substrate from a photocatalytic reaction as described in Patent Documents 1 and 2 described above. In the method using an undercoat as shown in Patent Document 1, since the undercoat and the photocatalyst coating film are transparent, there is an advantage that the photocatalytic function can be imparted to the substrate without impairing the design of the substrate. This method requires a lot of cost and time for the undercoating operation and its material. In addition, the performance (adhesion, decomposability, etc.) of the photocatalyst layer may be greatly affected by the degree of curing of the undercoat, and there is a problem that painting is difficult. In particular, when an existing building is to be painted on site, the time interval required for applying the photocatalytic paint after applying the undercoat is easily affected by temperature and humidity. There is.
[0007]
Further, the method using a colored paint as disclosed in Patent Document 2 has a problem that the design of the base material is impaired. In addition, photocatalytic paints usually use very expensive resin components such as silicone and fluorine so that the resin components are not decomposed by the photocatalyst. Is required to have a film thickness five times or more that of the transparent undercoat of about 20 μm described above, for example. As the film thickness increases, the coating film becomes brittle and cracks are easily generated, and the cost increases.
[0008]
An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a one-coat photocatalyst paint capable of protecting a substrate from a photocatalytic reaction with a simple configuration without impairing the design of the substrate.
[0009]
Means for Solving the Problems and Effects of the Invention
In order to achieve the above object, an invention according to claim 1 is a photocatalytic coating material in which a substrate has a photocatalytic function by being applied on the surface of the substrate, wherein the coating film transmits 50% or more of light having a wavelength of 500 nm. And a photocatalytic coating material that blocks light of 320 nm by 80% or more.
[0010]
In the above configuration, 50% or more of visible light having a wavelength of 500 nm is transmitted through the coating film, and at least 80% of light of 320 nm which is ultraviolet light is blocked. That is, by transmitting visible light through the coating film, the design of the base material is not impaired, and by blocking ultraviolet rays, the base material is protected from photocatalytic decomposition. Therefore, a photocatalytic paint which has both design properties and substrate protection properties and can be used as a one-coat paint is obtained. Thereby, low-cost, low-cost coating can be performed, and the coating film has excellent weather resistance, design properties, adhesion, and crack resistance.
[0011]
According to a second aspect of the present invention, in the photocatalytic paint according to the first aspect, the light transmittance at a wavelength of 500 nm is 70% or more, and the light blocking property at 320 nm is 90% or more. In this configuration, the design effect of the base material and the effect of preventing the photocatalytic decomposition of the base material are enhanced.
[0012]
A third aspect of the present invention is the photocatalytic coating according to the first aspect, wherein the light transmittance at a wavelength of 500 nm is 75% or more, and the light blocking property at 320 nm is 95% or more. In this configuration, the above-described effects are further enhanced.
[0013]
According to a fourth aspect of the present invention, there is provided a photocatalytic paint according to any one of the first to third aspects, wherein the average composition formula (I): R² _aSiO_b(OR¹)_c(OH)_dAnd R¹, R²And independently represent the same or different substituted or unsubstituted monovalent hydrocarbon groups, and a, b, c and d are a + 2b + c + d = 4, 0 ≦ a <3, 0 <b <2, 0 <c < 4, which is a number satisfying the relationship of 0 <d <4, and includes a partially hydrolyzed organosiloxane having a weight average molecular weight of 600 to 5,000 in terms of polystyrene. In this configuration, in addition to the effects described above, R² _aSiO_b(OR¹)_c(OH)_d, The coating film itself has high weather resistance.
[0014]
According to a fifth aspect of the present invention, in the photocatalytic paint according to any one of the first to fourth aspects, the coating thickness is 1 to 10 μm. In this configuration, crack resistance and low cost of the coating film can be ensured.
[0015]
According to a sixth aspect of the present invention, in the photocatalytic paint according to any one of the first to fifth aspects, the photocatalyst has a particle diameter of 10 to 30 nm. In this configuration, in addition to the above-described effects, it is possible to further secure the transparency, ultraviolet blocking property, crack resistance, and photocatalytic performance of the coating film.
[0016]
According to a seventh aspect of the present invention, in the photocatalytic coating according to any one of the first to sixth aspects, the content of titanium oxide in the solid content is 10 to 50%. In this configuration, it is possible to further ensure the transparency, ultraviolet blocking property, crack resistance, and photocatalytic performance of the coating film.
[0017]
According to an eighth aspect of the present invention, in the photocatalytic paint according to any one of the first to seventh aspects, at least one of zinc oxide and cerium oxide is contained. In this configuration, it is possible to further secure the ultraviolet shielding property of the coating film and prevent deterioration of the base, and the coating film itself has high weather resistance.
[0018]
According to a ninth aspect of the present invention, in the photocatalytic coating according to any one of the first to eighth aspects, silica having a particle diameter of 300 nm or more is included. In this configuration, the gloss of the coating film can be further controlled, the ultraviolet light can be scattered to prevent deterioration of the base and the coating film, and high crack resistance can be ensured. In addition, the rate of light incidence on the photocatalyst is increased due to the scattering of ultraviolet rays, and the photocatalytic performance is also improved.
[0019]
According to a tenth aspect of the present invention, in the photocatalytic paint according to any one of the first to ninth aspects, R²It contains a glycidyl group. In this configuration, the adhesion of the coating film to the substrate can be further ensured.
[0020]
The invention according to claim 11 is a photocatalytic paint according to any one of claims 1 to 10, wherein²It contains (meth) acrylic acid ester therein. In this configuration, the photocatalytic performance of the coating film is further increased, and the adhesion to the substrate can be improved.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the one-coat photocatalytic paint according to one embodiment of the present invention will be described. 1 (a) and 1 (b) show the coating structure of a substrate coated with the photocatalytic paint of the present invention. The photocatalyst paint 1 exhibits a great advantage when applied to the organic substrate 2 or the substrate 4 coated with the organic paint 3 serving as a base, but the photocatalyst paint 1 is an object to be coated. The substrate is not limited to the above. In particular, the photocatalytic paint 1 can be used as a one-coat paint as shown in FIG. Hereinafter, the organic paint 3, the photocatalyst paint 1, the coating films thereof, and the substrates 2, 4 will be sequentially described.
[0022]
The light transmission characteristics of the photocatalytic paint 1 will be described with reference to FIGS. As shown in FIG. 2A, the coating film made of the photocatalytic coating material 1 transmits 50% or more, preferably 70% or more, and more preferably 75% of visible light having a wavelength of 500 nm. The above is configured to transmit light. Further, as shown in FIG. 2 (b), the coating film made of the photocatalytic coating material 1 blocks 80% or more, preferably 90% or more, and more preferably 95% of ultraviolet light having a wavelength of 320 nm. % Or more.
[0023]
Since the photocatalyst paint 1 has such optical characteristics, the visible light portion of the light that enters the photocatalyst paint 1 from the space 5 passes through the photocatalyst paint layer with the same light transmittance as that of the light having a wavelength of 500 nm, and the substrate 2 And the reflected light from the substrate 2 is emitted to the space 5 through the photocatalytic paint layer with the same light transmittance as the incident light. That is, the surface of the substrate 2 can be seen almost without being hindered by the photocatalytic paint layer.
[0024]
In addition, since the ultraviolet portion of the light that enters the photocatalyst paint 1 from the space 5 passes through the photocatalyst paint layer having the same light blocking ratio as that of the light having the wavelength of 320 nm, the amount of the ultraviolet light reaching the base material 2 is small. . Therefore, the photocatalyst in the photocatalyst paint 1 near the substrate 2 is hardly activated, and the photocatalytic decomposition reaction of the substrate 2 hardly occurs.
[0025]
(Organic coating layer)
The organic coating layer is a coating layer formed between the photocatalytic coating layer and the substrate. The paint has an organic resin as a basic structure, and may contain a pigment, a solvent, water, and other additives such as a thickener and an antifoaming agent. As a general example, many paints are commercially available in which a pigment is mixed with a resin based on acrylic, acrylic urethane, acrylic silicon, fluorine, or the like, and water or an organic solvent is used as a solvent. Such an organic paint 3 may be any as long as it can be in close contact with the base material 4 and exhibit the required design properties.
[0026]
(Photocatalyst coating layer)
The heating residue at 500 ° C. of the photocatalytic paint used for forming the photocatalytic coating layer is preferably 55 to 95% by weight, more preferably 70 to 90% by weight, and still more preferably 80 to 90% by weight based on the weight of the original paint. 90% by weight. When the proportion of the heating residue is less than 55% by weight, the weather resistance of the photocatalyst coating layer tends to be low, and the photocatalytic coating tends to be easily decomposed. Since the ratio tends to be low, it is not preferable that the ratio of the heating residue is such.
[0027]
The photocatalytic coating material is not particularly limited, but includes, for example, transparency, weather resistance, durability, film forming property, storage stability of the coating material, and curability at a low temperature of 100 ° C. or lower (including normal temperature). In view of this, a silicone coating material composition containing the following components is preferred.
[0028]
Average composition formula (I): R² _aSiO_b(OR¹)_c(OH)_dAnd an organosiloxane partially hydrolyzed product having a weight average molecular weight of 600 to 5,000 in terms of polystyrene. Where R¹, R²Each independently represents a same or different substituted or unsubstituted monovalent hydrocarbon group, and a, b, c and d are a + 2b + c + d = 4, 0 ≦ a <3, 0 <b <2, 0 <c <4, 0 <d <4.
[0029]
R in the above formula (I)¹And R²And independently represent the same or different substituted or unsubstituted monovalent hydrocarbon groups. R¹And R²May be the same or different. Also, R¹When there are a plurality of¹May be the same or different from each other;²When there are a plurality of²May be the same or different.
[0030]
R²Is not particularly limited as long as it is a substituted or unsubstituted monovalent hydrocarbon group, but is preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms. For example, alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, and octyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; 2-phenylethyl group and 3-phenylpropy Aryl groups such as phenyl and tolyl groups; alkenyl groups such as vinyl and allyl groups; halogens such as chloromethyl group, γ-chloropropyl group and 3,3,3-trifluoropropyl group. Substituted hydrocarbon group; examples include substituted hydrocarbon groups such as a γ-methacryloxypropyl group, a γ-glycidoxypropyl group, a 3,4-epoxycyclohexylethyl group, and a γ-mercaptopropyl group. Among these, an alkyl group having 1 to 4 carbon atoms and a phenyl group are preferable in terms of ease of synthesis or availability.
[0031]
Also, R¹Is not particularly limited as long as it is a substituted or unsubstituted monovalent hydrocarbon group. For example, an alkyl group having 1 to 4 carbon atoms is preferable from the viewpoint of crosslinking reactivity of the organosiloxane partial hydrolyzate. The method for preparing the organosiloxane partial hydrolyzate is not particularly limited. For example, R in the above formula (I)¹Is an alkyl group (OR¹Is an alkoxy group). Silanol obtained by hydrolyzing one or more hydrolyzable organosilanes selected from the group consisting of hydrolyzable organochlorosilanes and hydrolyzable organoalkoxysilanes with a large amount of water by a known method. By partially alkoxylating the silanol groups of the group-containing polyorganosiloxane, a partially hydrolyzed organosiloxane can be obtained.
[0032]
In this preparation method, when the hydrolysis is performed using a hydrolyzable organoalkoxysilane, the unreacted alkoxy group and the silanol are obtained by hydrolyzing only a part of the alkoxy group by adjusting the amount of water. Since an organosiloxane partial hydrolyzate in which a group coexists can be obtained, the above-mentioned treatment for partially alkoxylating the silanol group of the silanol group-containing polyorganosiloxane may be omitted.
[0033]
The hydrolyzable organochlorosilane is not particularly limited, and examples thereof include methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, and diphenyldichlorosilane. The hydrolyzable organoalkoxysilane is not particularly limited, but may be, for example, a compound represented by the general formula (II): R² _mSi (OR¹)_4-mOf the hydrolyzable organosilanes represented by¹Is an alkyl group. Where R¹, R²Is the same as that in the above formula (I), and m is an integer of 0 to 3.
[0034]
Specifically, examples of the tetraalkoxysilane with m = 0 include tetramethoxysilane and tetraethoxysilane, and examples of the organotrialkoxysilane with m = 1 include methyltrimethoxysilane, methyltriethoxysilane, and methyltriethoxysilane. Examples include isopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and 3,3,3-trifluoropropyltrimethoxysilane.
[0035]
Examples of the diorganodialkoxysilane of m = 2 include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane, and the like. Examples thereof include trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, trimethylisopropoxysilane, and dimethylisobutylmethoxysilane.
[0036]
The catalyst used for partially hydrolyzing the hydrolyzable organosilane is not particularly limited, and examples of the acidic catalyst include water-soluble acids such as hydrochloric acid and nitric acid, and acidic colloidal silica. Examples of the neutral catalyst include an aqueous ammonia solution and basic colloidal silica.
[0037]
A, b, c and d in the above formula (I) representing the organosiloxane partial hydrolyzate are numbers satisfying the above-mentioned relationship. When a is 3 or more, there is an inconvenience that curing of the coating film does not proceed well. Those having b = 0 are monomers and have a problem that a cured film cannot be formed. When b is 2, silica (SiO₂(Not an organosiloxane)), and there is a problem in that cracks occur in the cured film.
[0038]
In the case of c = 0, the molecular terminal is R²Since only the group and the OH group, which is a hydrophilic group, are included, the hydrophilicity of the whole molecule increases, and the long-term stability of the resin cannot be obtained. Those having c = 4 are monomers and have a problem that a cured film cannot be formed. Further, in the case of d = 0, the molecular terminal is R²Group and OR¹Is advantageous for the long-term stability of the resin since only the hydrophobic group of the¹Since the base lacks crosslinking reactivity during curing of the coating film, a sufficient cured film cannot be obtained. Those having d = 4 are monomers and have a problem that a cured film cannot be formed.
[0039]
The weight average molecular weight of the organosiloxane partial hydrolyzate (A) is generally in the range of 600 to 5000, preferably 2000 to 4000, more preferably 2500 to 3000 in terms of polystyrene. When the weight average molecular weight is less than 600, there are disadvantages such as generation of cracks in the cured coating film, and when it exceeds 5,000, the curing does not proceed well.
[0040]
The organosiloxane partial hydrolyzate (A) has the above structure, and its weight-average molecular weight is within the above-mentioned predetermined range, so that it has high reactivity. Therefore, a photocatalyst paint containing the same does not require a curing catalyst to cure the coating film when heated to 100 ° C. or higher. In addition, if a curing catalyst is used, curing at a low temperature of 100 ° C. or lower and curing at room temperature can be performed. In addition, the organosiloxane partial hydrolyzate (A) is stable for a long period of time because it has a good hydrophilic-hydrophobic balance of its molecular terminal groups, despite its high reactivity.
[0041]
The compounding amount of the organosiloxane partial hydrolyzate (A) in the photocatalytic coating composition is not particularly limited, but is, for example, preferably 5 to 40% by weight, more preferably 10 to 35% by weight, based on the total amount of the composition. More preferably, the ratio is 20 to 30% by weight. If the amount is less than 5% by weight, the strength of the coating film is reduced, a durable coating film cannot be formed, the transparency of the coating film is reduced, and the curing is inhibited. Or tend to. If the amount exceeds 40% by weight, the transparency of the coating film tends to decrease, the coating film tends to crack, and the stability of the photocatalytic coating composition tends to decrease.
[0042]
The photocatalyst used for the photocatalyst layer forming paint is not particularly limited, for example, titanium oxide, zinc oxide, tin oxide, iron oxide, zirconium oxide, tungsten oxide, chromium oxide, molybdenum oxide, ruthenium oxide, germanium oxide, Examples include metal oxides such as lead oxide, cadmium oxide, copper oxide, vanadium oxide, niobium oxide, tantalum oxide, manganese oxide, cobalt oxide, rhodium oxide, nickel oxide, rhenium oxide, and strontium titanate. it can.
[0043]
Among these, the above metal oxides are preferable in that they can be easily used practically, and among the metal oxides, titanium oxide, zinc oxide, tin oxide, zirconium oxide, tungsten oxide, iron oxide, and niobium oxide are It is preferable in that it shows activity even when baking is performed at a low temperature of 100 ° C. or less. Further, among these, titanium oxide is particularly preferable in view of its photocatalytic performance, curing acceleration performance, safety, availability, and cost. When titanium oxide is used as the photocatalyst, it is better to use an anatase type (anatase type) crystal as the photocatalyst performance and curing acceleration performance, as well as to exhibit long-term, photocatalytic performance and curing acceleration. This is preferable in that the performance is developed in a shorter time.
[0044]
The shape of the photocatalyst (D) is not particularly limited, and examples thereof include a granular shape and a needle shape. From the viewpoint of mixing stability and dispersion stability, granular, particularly fine particles are preferred. The photocatalyst can be used as long as it finally exhibits the properties of an optical semiconductor, and is not limited by the raw material state.
[0045]
The particle size of the photocatalyst is not particularly limited, but is preferably 1 to 100 nm, and more preferably 6 to 50 nm, in order to stably disperse and prevent precipitation of a hard cake or the like. Is more preferable, and further preferably 10 to 30 nm. When the particle diameter is smaller than 10 nm, cracks are easily generated in the coating film, and when the particle diameter is larger than 30 nm, the photocatalytic performance decreases and the transparency of the coating film decreases.
[0046]
One photocatalyst may be used alone, or two or more photocatalysts may be used in combination. It is known that a photocatalyst generates active oxygen (photocatalytic property) when irradiated with light (ultraviolet light) having an excitation wavelength (for example, 320 nm). Since active oxygen can oxidize and decompose organic substances, its characteristics are used to make use of the properties of carbon-based dirt components (for example, carbon fractions contained in automobile exhaust gas and tobacco dust). Self-cleaning effect to decompose, etc .; deodorant effect to decompose malodorous components typified by amine compounds and aldehyde compounds; antibacterial effect to prevent the generation of bacterial components typified by Escherichia coli and Staphylococcus aureus; Obtainable.
[0047]
In addition, when ultraviolet light is applied to the coating film containing the photocatalyst, the photocatalyst converts water into a hydroxyl radical by the photocatalysis. The hydroxyl radicals decompose and remove dirt such as organic substances that adhere to the surface of the coating film and repel water, thereby improving the hydrophilicity (wetting) of the coating film with respect to water. Effects such as anti-fogging property that is hardly fogged and anti-fouling property by washing with rainwater can be obtained at a higher level or maintained for a long time by a coating film containing a photocatalyst.
[0048]
Furthermore, the photocatalytic action also has an antistatic function, which further improves the antifouling effect. For example, when a coating film containing a photocatalyst is irradiated with ultraviolet rays, the surface resistance of the coating film is reduced by the action of the photocatalyst contained in the coating film, thereby exhibiting an antistatic effect, and the coating film surface is less likely to be stained. The mechanism by which the surface resistance of the coating decreases when the photocatalyst-containing coating is irradiated with ultraviolet light has not yet been clearly confirmed. It is considered that the surface resistance of the coating film is reduced by the action of the metal.
[0049]
Commercially available photocatalysts are available as powders or dispersions. Many dispersions are aqueous dispersions, but some organic solvent dispersions are also available. The aqueous dispersion of the photocatalyst generally contains 1 to 30% by weight of the photocatalyst as a solid content, and the photocatalyst is acidic or basic and stably dispersed. The method for dispersing the powder-based photocatalyst is not particularly limited, and an ordinary dispersion method may be used. At that time, a dispersing aid, a coupling agent and the like can be used.
[0050]
When the metal is supported on the surface of the photocatalyst, the photocatalytic effect of the photocatalyst is further enhanced. Although the mechanism has not been clearly confirmed, the separation of the charge of the photocatalyst is promoted by supporting the metal on the surface of the photocatalyst, and the loss probability of electrons and holes generated by the charge separation is small. Is considered to be related.
[0051]
As the metal that may be supported on the surface of the photocatalyst, for example, silver, copper, iron, nickel, zinc, platinum, gold, palladium, cadmium, cobalt, rhodium, ruthenium, and the like, in that the charge separation of the photocatalyst is further promoted. preferable. The supported metal may be only one kind or two or more kinds. The amount of metal supported is not particularly limited, but is preferably, for example, 0.1 to 10% by weight, and more preferably 0.2 to 5% by weight, based on the photocatalyst. If the loading is less than 0.1% by weight, the loading effect tends not to be sufficiently obtained. If the loading exceeds 10% by weight, the effect does not increase so much. Problems tend to occur.
[0052]
The method for supporting the metal is not particularly limited, and examples thereof include an immersion method, an impregnation method, and a photoreduction method. The photocatalyst may be used in the form of a clay cross-linked body in which it is inserted between layers. The reason is that the photocatalyst is dispersed in the form of fine particles between the layers, and the photocatalytic performance is improved.
[0053]
The blending amount of the photocatalyst in the photocatalytic coating varies depending on the photocatalytic performance of the photocatalyst, its required effect, antifouling property, intended use, etc., but is preferably 5 to 80% by weight based on the total solid content in the coating. , More preferably 10 to 70% by weight, even more preferably 10 to 50% by weight. When the blending amount of the photocatalyst is less than 20% by weight, the photocatalytic performance is weakly expressed, and the antifouling property tends not to be expected. In addition, the performance of blocking ultraviolet rays by titanium oxide itself becomes insufficient, and the base is decomposed. there is a possibility. If the amount of the photocatalyst exceeds 50% by weight, the ratio of the photocatalyst in the coating film increases, and the strength of the coating film decreases, a durable coating film cannot be formed, or the coating film becomes transparent. There is a tendency that the properties are reduced or the curing is inhibited.
[0054]
The photocatalytic paint may have an average composition formula (III): HO (R³ ₂SiO)_nH (where R³Represents a monovalent hydrocarbon group, and n is a number satisfying 3 ≦ n ≦ 50 (hereinafter referred to as “linear polysiloxane diol” or simply “linear polysiloxane diol”). Polysiloxane diol "). The polysiloxane diol promotes the curing of the composition to more reliably achieve curing at a low temperature of 100 ° C. or lower, or imparts toughness (flexibility) to the cured coating applied to the composition to provide the coating with a high durability. It is a component for improving the cracking property and imparting water repellency or non-tackiness to the surface of the coating.
[0055]
In the above average composition formula (III) representing a linear polysiloxane diol containing a hydroxyl group at both ends,³Is not particularly limited as long as it is a monovalent hydrocarbon group. For example, R in the formula (I)²The same as described above can be used. Such R³Among the linear polysiloxane diols having dimethyl siloxane diol and methyl phenyl siloxane diol, from the viewpoint of not lowering the weather resistance of the cured film, further improving the crack resistance of the film, and being easily available, Is preferred.
[0056]
The linear polysiloxane diol containing hydroxyl groups at both ends is a molecule having relatively low reactivity because it has no reactive group other than the OH group at the molecular end. Therefore, in the cured coating, only the molecular ends of the polysiloxane diol are in a state of being bonded or not bonded to the organosiloxane partial hydrolyzate (A) component. Since the main chain of the polysiloxane diol has a two-dimensional structure and exists in a relatively mobile state, it is possible to absorb the curing shrinkage due to the crosslinking of the component (A) and prevent the occurrence of cracks.
[0057]
In addition, the polysiloxane diol has hydroxyl groups at both ends of which the OR of the organosiloxane partial hydrolyzate (A) component is¹Since it can be relatively easily bonded to a group, the structure as a cross-linking agent between molecules of the component (A) can be formed at a low temperature of 100 ° C. or less. Therefore, OR of component (A)¹If there is a hydroxyl group of the polysiloxane diol corresponding to the group, curing of the coating film at a low temperature of 100 ° C. or less can be more reliably achieved. In other words, the polysiloxane diol can provide both effects of softening and accelerating the curing of the coating film formed by the photocatalytic paint.
[0058]
These effects are greatest in the polysiloxane diol where n in the formula (III) is in the range of 3 ≦ n ≦ 50 (preferably 5 ≦ n ≦ 45, more preferably 5 ≦ n ≦ 40). Since polysiloxane diol is linear, it easily absorbs curing stress and easily forms a network structure as a crosslinking agent. The larger the value of n, the greater the effect as a softening agent. If the value of n is less than 3, there is no effect as a softening agent.
[0059]
In addition, the smaller the value of n, the higher the reactivity of the terminal -OH group, so that the effect as a curing agent is high, and the n is taken into the inside of the cured film. As n becomes larger, compatibility becomes poor and a part of the polysiloxane diol tends to be released to the surface of the cured film, so that the effect of imparting water repellency or non-tackiness to the surface of the cured film becomes large. When n is larger than 50, the compatibility is further reduced, and the reactivity of the terminal -OH group is reduced, so that the effect as a curing agent tends to be low or the molecule thereof tends to be large. There is a possibility that phase separation or white turbidity or the like may be caused in the coating film because it is not taken into the coating film at all.
[0060]
The blending amount of the polysiloxane diol in the composition of the photocatalytic paint varies depending on the size of n and is not particularly limited. For example, the amount is preferably 0.1 to 100% by weight based on the organosiloxane partial hydrolyzate (A) component. %, More preferably 1 to 30% by weight, even more preferably 2 to 20% by weight. If the amount is less than 0.1% by weight, a sufficient network structure as a cross-linking agent may not be formed, or a softening effect may not be expected. If the amount exceeds 100% by weight, unbonded polysiloxane diol may be used. There is a tendency for inconvenience such as inhibition of curing of the coating film.
[0061]
By mixing an appropriate amount of polysiloxane diol from large to small n with respect to the organosiloxane partial hydrolyzate (A) component, the curability at a low temperature of 100 ° C. or lower is higher and the crack resistance is lower. A silicone coating material composition capable of forming an improved cured film is obtained.
[0062]
Photocatalytic paint, if necessary, at least selected from the group consisting of alkyd resin, epoxy resin, acrylic resin, acrylic silicone resin, phenolic resin, fluororesin, polyester resin, chlorinated rubber resin, urethane resin and melamine resin One type of organic resin can also be included.
[0063]
These organic resins are components that can impart toughness (flexibility) to the cured coating film of the photocatalytic coating composition and improve the crack resistance of the coating film. The silicone resin, which is an essential component of the photocatalytic coating composition, and the organic resin generally lack compatibility with each other in an organic solvent system, and thus tend to cause phase separation in a solution and cloudiness of the coating in a coated film. It is in. However, this problem can be avoided by introducing a functional group that improves compatibility with the silicone resin component, or conversely, by introducing a functional group that improves compatibility with the silicone component into the organic resin.
[0064]
When the organic resin is contained as a composition of the photocatalytic coating, the amount of the organic resin depends on the type of the organic resin and is not particularly limited, but does not hinder the curing of the organosiloxane partial hydrolyzate (A) component and is necessary. As long as it is within a range in which the obtained flexibility is imparted, for example, it is preferably 1 to 50% by weight, more preferably 5 to 20% by weight, based on the component (A). If the amount is less than 1% by weight, sufficient flexibility may not be obtained. If the amount is more than 50% by weight, the curing of the component (A) may be inhibited, or the photo-catalyst may cause the decomposition and deterioration of the applied cured film to proceed. There is a possibility that the durability of the resin may decrease.
[0065]
When the photocatalyst paint containing the organic resin as an additional component is used to form a coating and cured film on the surface of a member used in an environment where natural light is applied, such as outdoors, the organic resin is as follows: It is preferred to be the component F). The component (F) has the general formula (IV): CH₂= CR⁴(COOR⁵(Where R⁴Represents a hydrogen atom and / or a methyl group).⁵Is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 9 carbon atoms, a first (meth) acrylate ester;⁵Is a second (meth) acrylate ester selected from the group consisting of an epoxy group, a glycidyl group and a hydrocarbon group containing at least one of them, and R⁵Is an acrylic resin which is a copolymer with a third (meth) acrylate ester which is a hydrocarbon group containing an alkoxysilyl group and / or a halogenated silyl group (hereinafter referred to as "acrylic resin (F)"). .
[0066]
In this specification, (meth) acrylate refers to either or both of acrylate and methacrylate. The acrylic resin (F) has an effect of improving the toughness of the applied cured film of the photocatalytic coating composition, thereby preventing the occurrence of cracks and increasing the film thickness. In addition, the acrylic resin (F) is incorporated into the condensation crosslinked product of the component (A) which becomes the three-dimensional skeleton of the cured coating film of the photocatalytic coating composition, and makes the condensation crosslinked product acrylic-modified. When the condensation cross-linked product is modified with acrylic, the adhesion of the cured coating film of the photocatalytic coating composition to the substrate is further improved.
[0067]
The first (meth) acrylic ester, which is one of the constituent monomers of the acrylic resin (F), is represented by R in the above formula (IV).⁵Is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 9 carbon atoms, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl Groups, tert-butyl, pentyl, hexyl, heptyl, octyl and other alkyl groups; cyclopentyl and cyclohexyl and other cycloalkyl groups; 2-phenylethyl, 2-phenylpropyl and 3-phenylpropyl Aralkyl groups such as a group; aryl groups such as a phenyl group and a tolyl group; halogenated hydrocarbon groups such as a chloromethyl group, γ-chloropropyl group and 3,3,3-trifluoropropyl group; At least one of the following:
[0068]
The second (meth) acrylic acid ester as another constituent monomer of the acrylic resin (F) is represented by R in the above formula (IV).⁵Is at least one group selected from the group consisting of an epoxy group, a glycidyl group, and a hydrocarbon group containing at least one of them (for example, γ-glycidoxypropyl group and the like). Is a seed.
[0069]
The third (meth) acrylic ester, which is still another constituent monomer of the acrylic resin (F), is represented by R in the above formula (IV).⁵Is a hydrocarbon group containing an alkoxysilyl group and / or a halogenated silyl group, for example, a trimethoxysilylpropyl group, a dimethoxymethylsilylpropyl group, a monomethoxydimethylsilylpropyl group, a triethoxysilylpropyl group, a diethoxymethylsilylpropyl group Ethoxydimethylsilylpropyl group, trichlorosilylpropyl group, dichloromethylsilylpropyl group, chlorodimethylsilylpropyl group, chlorodimethoxysilylpropyl group, dichloromethoxysilylpropyl group and the like.
[0070]
The acrylic resin (F) is a copolymer of a (meth) acrylic ester containing at least one kind and a total of at least three kinds in the first, second, and third (meth) acrylates, respectively. One or more selected from the first, second, and third (meth) acrylates, or one or two or more selected from (meth) acrylates other than the above. Copolymers containing more than one species may be used.
[0071]
The first (meth) acrylic acid ester is a component for improving the toughness of a cured coating applied with a photocatalytic paint. For this, R⁵It is preferable that the substituted or unsubstituted hydrocarbon group has a certain volume or more, and preferably has 2 or more carbon atoms. The second (meth) acrylic acid ester is a component for improving the adhesion between the applied cured film of the photocatalytic paint and the substrate.
[0072]
The third (meth) acrylic acid ester forms a chemical bond between the acrylic resin (F) and the organosiloxane partial hydrolyzate (A) component when the silicone emulsion coating composition is cured. Thereby, the acrylic resin (F) is fixed in the applied cured film. Further, the third (meth) acrylic acid ester also has an effect of improving the compatibility between the acrylic resin (F) and the component (A).
[0073]
The molecular weight of the acrylic resin (F) greatly affects the compatibility between the acrylic resin (F) and the component (A). Therefore, the acrylic resin (F) preferably has a weight average molecular weight in terms of polystyrene in the range of 1,000 to 50,000, more preferably 1,000 to 20,000. If the weight average molecular weight in terms of polystyrene of the acrylic resin (F) exceeds 50,000, phase separation may occur and the coating film may be whitened. If the molecular weight is less than 1,000, the toughness of the coating film tends to decrease, and cracks tend to occur.
[0074]
The second (meth) acrylic acid ester is desirably at least 2% by mole of the monomer in the copolymer. If it is less than 2%, the adhesion of the coating film tends to be insufficient. The third (meth) acrylic acid ester is desirably in the range of 2 to 50% by mole ratio of the monomer in the copolymer. If it is less than 2%, the compatibility between the acrylic resin (F) and the component (A) is poor, and the coating film may be whitened. On the other hand, if it exceeds 50%, the bond density between the acrylic resin (F) and the component (A) becomes too high, and the improvement in toughness, which is the original purpose of the acrylic resin, tends not to be observed.
[0075]
As a method for synthesizing the acrylic resin (F), for example, a radical polymerization method by solution polymerization, emulsion polymerization, or suspension polymerization in a known organic solvent, or an anion polymerization method or a cationic polymerization method can be used. It does not specify. In the radical polymerization method by solution polymerization, for example, the first, second and third (meth) acrylate monomers are dissolved in an organic solvent in a reaction vessel by a known method, and the radical polymerization is started. The agent is added, and the mixture is heated and reacted under a nitrogen stream. The organic solvent used at this time is not particularly limited, for example, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol monoethyl acetate Are used.
[0076]
Further, the radical polymerization initiator is not particularly limited. For example, cumene hydroperoxide, tertiary butyl hydroperoxide, dicumyl peroxide, ditertiary butyl peroxide, benzoyl peroxide, acetyl peroxide, lauroyl peroxide, azo Bisisobutyronitrile, hydrogen peroxide-Fe²⁺Salt, persulfate-NaHSO₃, Cumene hydroperoxide-Fe²⁺Salts, benzoyl peroxide-dimethylaniline, peroxide-triethylaluminum and the like are used. In order to control the molecular weight, a chain transfer agent can be added.
[0077]
Examples of the chain transfer agent include, but are not particularly limited to, quinones such as monoethylhydroquinone and p-benzoquinone; mercaptoacetic acid-ethyl ester, mercaptoacetic acid-n-butyl ester, and mercaptoacetic acid. Thiols such as 2-ethylhexyl ester, mercaptocyclohexane, mercaptocyclopentane and 2-mercaptoethanol; thiophenols such as di-3-chlorobenzenethiol, p-toluenethiol and benzenethiol; γ-mercaptopropyltrimethoxysilane and the like Phenylpicrylhydrazine; diphenylamine; tert-butylcatechol and the like.
[0078]
The thickness of the photocatalyst coating layer is not particularly limited and is, for example, preferably about 0.1 to 50 μm, but these coating layers are stably adhered and held for a long time, and cracks and peeling do not occur. Therefore, the thickness is more preferably 1 to 10 μm.
[0079]
The photocatalyst paint may further include a curing catalyst, if necessary. It is not always necessary to include a curing catalyst, but by promoting the condensation reaction of the organosiloxane partial hydrolyzate (A), heat curing of the coated film can be promoted, and the coated film can be formed at a low temperature of 100 ° C or lower and at room temperature. If necessary, a curing catalyst may be included for the purpose of curing. Examples of the curing catalyst include, but are not particularly limited to, alkyl titanates; metal carboxylate salts such as tin laurate, tin octylate, iron octylate, lead octylate, dibutyltin dilaurate, and dioctyltin dimaleate; Amine compounds such as hexylamine and guanidine and their hydrochlorides; carboxylic acid salts of amines such as dibutylamine-2-hexoate, dimethylamine acetate, ethanolamine acetate; quaternary ammonium salts of carboxylic acids such as tetramethylammonium acetate; tetraethyl Amines such as pentamine, amine silane coupling agents such as N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane; p-toluenesulfonic acid , Phthalic acid, hydrochloric acid Aluminum compounds such as aluminum alkoxides and aluminum chelates; alkali metal salts such as lithium acetate, potassium acetate, lithium formate, sodium formate, potassium phosphate, potassium hydroxide; tetraisopropyl titanate, tetrabutyl titanate, titanium tetraacetylacetate Titanium compounds such as nitrates; at least one of halogenated silanes such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylmonochlorosilane can be used. However, other than these, there is no particular limitation as long as it is effective for accelerating the condensation reaction of the organosiloxane partial hydrolyzate (A).
[0080]
If necessary, the photocatalytic coating material may contain components other than the above, for example, silica particles having a relatively large particle size (300 nm or more) used as a light scattering agent or a matting agent, and inorganic ultraviolet absorbers such as zinc oxide and cerium oxide. Various additives such as a dispersant, a leveling agent, a metal powder, an antibacterial agent (preferably an inorganic antibacterial agent), an antioxidant, an antistatic agent, an antifoaming agent, and a fungicide may also adversely affect the effects of the present invention. It can be included within the range not given. The amounts of these additives are not particularly limited, and may be set as appropriate.
[0081]
The method of applying each paint used for forming the photocatalyst coating layer and, if necessary, the organic coating layer serving as a base is not particularly limited. For example, brush coating, spraying, dipping (dipping) Various coating methods such as bar, flow, roll, curtain, knife coating, and spin coating can be selected. A method for curing each coating material applied to the base material may be a known method, and is not particularly limited. In addition, the temperature at the time of curing is not particularly limited, and a wide range from room temperature to a temperature by heating depending on the desired coated cured film performance, the use of a curing catalyst, the heat resistance of the photocatalyst or the substrate, and the like. Can be taken.
[0082]
〔Base material〕
The substrate on which the photocatalytic paint of the present invention is applied is not particularly limited, but, for example, an inorganic substrate, an organic substrate, an inorganic-organic composite substrate, and at least a surface of any one of these substrates A substrate having one inorganic coating and / or at least one organic coating (hereinafter referred to as a coating substrate) may be used.
[0083]
Examples of the inorganic substrate include, but are not particularly limited to, a metal substrate; a glass substrate; an enamel; a water glass decorative plate, an inorganic building material such as an inorganic cured product, and ceramics. The metal substrate is not particularly limited. For example, non-ferrous metals [eg, aluminum (JIS-H4000 etc.), aluminum alloys (duralumin etc.), copper, zinc etc.], iron, steel [eg, rolled steel (JIS) -G3101, etc.), hot-dip galvanized steel (JIS-G3302, etc.), (rolled) stainless steel (JIS-G4304, G4305, etc.), tinplate (JIS-G3303, etc.), and other metals (including alloys). Can be
[0084]
The glass substrate is not particularly limited, and examples thereof include sodium glass, Pyrex (registered trademark) glass, quartz glass, and alkali-free glass. The enamel is obtained by baking and coating a vitreous enamel on a metal surface. Examples of the base metal include a mild steel plate, a steel plate, cast iron, and aluminum, but are not particularly limited. The enamel may be a normal enamel, and is not particularly limited.
[0085]
The water glass decorative board refers to, for example, a decorative board or the like obtained by applying sodium silicate to a cement base such as a slate board and baking it. The inorganic hardened material is not particularly limited. For example, fiber-reinforced cement boards (JIS-A5430 and the like), ceramic siding (JIS-A5422 and the like), wood wool cement boards (JIS-A5404 and the like), pulp cement boards ( JIS-A5414), slate / wood wool cement laminates (JIS-A5426, etc.), gypsum board products (JIS-A6901, etc.), clay roof tiles (JIS-A5208, etc.), thick slate boards (JIS-A5402, etc.), Ceramic tile (JIS-A5209, etc.), concrete block for construction (JIS-A5406, etc.), terrazzo (JIS-A5411, etc.), prestressed concrete double T slab (JIS-A5412, etc.), ALC panel (JIS-A5416, etc.), Hollow prestressed concrete panel (JIS-A6 11, etc.), common bricks (JIS-R1250 and the like) curing an inorganic material such, refers to a substrate in general obtained by molding.
[0086]
The slate board generally refers to a board made of fiber and cement and used for building members and the like. The fibers are not particularly limited, and may be, for example, asbestos, glass wool, rock wool, and the like. The slate plate has a different "sucking amount" when a coating material is applied, depending on its properties (porosity). However, the amount is not particularly limited, and may be any.
[0087]
The ceramic substrate is not particularly limited, and examples thereof include alumina, zirconia, silicon carbide, silicon nitride, and the like.
[0088]
The organic substrate is not particularly limited, and examples thereof include wood, wood, and paper. Further, plastic substrates are also included in the category of organic substrates. In the present invention, a substrate which is easily attacked by a photocatalyst, such as this plastic substrate, can be used. The plastic substrate is not particularly limited. For example, a thermosetting or thermoplastic plastic such as a polycarbonate resin, an acrylic resin, an ABS resin, a vinyl chloride resin, an epoxy resin, a phenol resin, and the like, and a nylon fiber And fiber reinforced plastics (FRP) reinforced with organic fibers.
[0089]
The inorganic-organic composite substrate is not particularly limited, and examples thereof include a fiber-reinforced plastic (FRP) in which the above plastic is reinforced with inorganic fibers such as glass fiber and carbon fiber. The organic film constituting the coating substrate is not particularly limited, for example, acrylic, alkyd, polyester, epoxy, urethane, acrylic silicone, chlorinated rubber, phenol, melamine, etc. A cured film of a coating material containing an organic resin may be used.
[0090]
Among the above-mentioned coating substrates, when the coating is composed of an inorganic substance, the inorganic coating is not particularly limited, and includes, for example, a cured coating of a coating material containing an inorganic resin such as a silicone resin. In order to further improve the adhesion between the base material and each coating (coating) layer, if necessary, a primer layer may be formed on the surface of the base material before applying each paint. Good. The primer layer is not particularly limited, regardless of whether it is organic or inorganic. Examples of the organic primer layer include a nylon resin, an alkyd resin, an epoxy resin, an acrylic resin, and an organic modified silicone resin (for example, an acrylic silicone resin). , A cured resin layer of an organic primer composition containing at least one organic resin selected from the group consisting of a chlorinated rubber resin, a urethane resin, a phenol resin, a polyester resin and a melamine resin in a solid content of 10% by weight or more. Examples of the inorganic primer layer include a cured resin layer of an inorganic primer composition containing 90% by weight or more of a solid content of an inorganic resin such as a silicone resin.
[0091]
The thickness of the primer layer is not particularly limited, but is preferably, for example, 0.1 to 50 μm, and more preferably 0.5 to 10 μm. If the thickness is too small, the desired adhesion may not be obtained. If the thickness is too large, foaming or the like may occur during drying. A substrate having at least one organic primer layer and / or inorganic primer layer on the surface as described above is included in the category of the coated substrate. That is, the coating film on the surface of the coating substrate may be the primer layer.
[0092]
The form of the substrate is not particularly limited, and examples thereof include a film, a sheet, a plate, and a fiber. Further, the base material may be a molded body of a material having such a shape, or a structure partially including at least one of the material having such a shape or a molded body thereof. The base material may be composed of the above-mentioned various materials alone, a composite material obtained by combining at least two of the above-described various materials, or a laminated material obtained by laminating at least two of the above-described various materials. May be.
[0093]
The coated article formed by applying the photocatalytic coating of the present invention is used as various materials or articles, or by equipping the coated article on at least a part of various materials or articles, for example, to be suitably used for the following applications. be able to. Building-related members or articles, for example, exterior materials (for example, exterior wall materials, flat roof tiles, Japanese roof tiles, metal roof tiles, etc.), resin rain boots such as PVC rain boots, and metal rain boots such as stainless steel rain boots Rain gutters, gates and members used for them (for example, gates, gate posts, gate walls, etc.), fences (fences) and members used therefor, garage doors, home terraces, doors, pillars, carports, bicycle parking Ports, sign posts, home delivery posts, wiring equipment such as switchboards and switches, gas meters, intercoms, TV doorphones and camera lens units, electric locks, entrance poles, rims, ventilating fan outlets, glass for buildings, etc .; windows (eg, daylighting) Windows, skylights, louvers, etc.) and members for use therewith (eg, window frames, shutters, blinds, etc.), automobiles, railway vehicles, aircraft, ships, machinery Road peripheral members (for example, soundproof walls, tunnel interior boards, various display devices, guardrails, car stops, railing, traffic signposts and signposts, traffic lights, post cones, etc.), advertising towers, outdoor or indoor lighting fixtures and the like Members for use (for example, members containing at least one material selected from the group consisting of glass, resin, metal, and ceramics), solar cell glass, agricultural vinyl and glass houses, and air conditioner outdoor units , VHF, UHF, BS, CS and other antennas.
[0094]
The coated article of the present invention may be one in which each paint is directly applied to at least a part of the above-mentioned various materials or articles and cured. The present invention is not limited to this. For example, a film obtained by applying each coating material on the surface of a film base material and curing the same may be attached to at least a part of the above-described various materials or articles. Examples of the material of the base material of such a film include polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, vinyl chloride resin, acrylic resin, fluororesin, polypropylene (PP) resin, and composite resins thereof. But are not particularly limited.
[0095]
【Example】
Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
[0096]
(Preparation Example A-1) In a flask equipped with a stirrer, a heating jacket, a condenser, and a thermometer, IPA-ST (isopropanol-dispersed colloidal silica sol: particle diameter of 10 to 20 nm, solid content of 30%, moisture of 0.5%, Nissan) 100 g, 68 g of methyltrimethoxysilane and 2.2 g of water were added thereto, and the mixture was hydrolyzed at a temperature of 65 ° C. for 5 hours with stirring, cooled, and the organosiloxane partial hydrolyzate (A) was cooled. Obtained. This had a solid content of 36% when left at room temperature for 48 hours. The component (A) obtained here is called A-1. Table 1 shows the preparation conditions for the component A-1.
[0097]
[Table 1]

[0098]
(Preparation Example B-1) 5.69 g (40 mmol) of n-butyl methacrylate (BMA) and trimethoxysilyl were placed in a flask equipped with a stirrer, a heating jacket, a condenser, a dropping funnel, a nitrogen gas inlet / outlet, and a thermometer. 1.24 g (5 mmol) of propyl methacrylate (SMA), 0.71 g (5 mmol) of glycidyl methacrylate (GMA), and 0.784 g (4 mmol) of γ-mercaptopropyltrimethoxysilane as a chain transfer agent were dissolved in 8.49 g of toluene. A solution obtained by dissolving 0.025 g (0.15 mmol) of azobisisobutyronitrile in 3 g of toluene was added dropwise to the reaction solution under a nitrogen stream, and the mixture was reacted at 70 ° C. for 2 hours. A polymer having a weight average molecular weight of 1,000 was obtained. The acrylic resin solution obtained here is called B-1. The molecular weight was determined by gel permeation chromatography (measurement model: HLC-802UR, manufactured by Tosoh Corporation) in terms of standard polystyrene. The subsequent molecular weight was measured in the same manner. Table 2 shows the conditions for preparing B-1.
[0099]
[Table 2]

[0100]
(Preparation Example D-1) A solution of 220 g (1 mol) of methyltriisopropoxysilane in 150 g of toluene was charged into a flask equipped with a stirrer, a heating jacket, a condenser, a dropping funnel, and a thermometer, and 108 g of a 1% hydrochloric acid aqueous solution was mixed as described above. The solution was added dropwise over 20 minutes to hydrolyze methyltriisopropoxysilane. After 40 minutes from the dropping, stirring was stopped, and a mixed solution of water and isopropyl alcohol in the lower layer containing a small amount of hydrochloric acid separated into two layers was separated, and hydrochloric acid remaining in the resin solution of toluene remaining after was removed by washing with water. The toluene was further removed under reduced pressure, and the mixture was diluted with isopropyl alcohol to obtain a 40% solution of a silanol group-containing organopolysiloxane having a weight average molecular weight of about 2,000 in isopropyl alcohol. This is called D-1.
[0101]
(Formulation Example 1) Photocatalytic paint 1 was prepared by mixing and stirring the components and amounts shown in Table 1 below.
[0102]
[Table 3]

[0103]
<Example 1>
On a surface of a 5 cm × 17 cm slate plate, “penetrating epoxy sealer” manufactured by Shinto Paint Co., Ltd. is applied with a roller at 150 g / m.²And dried at room temperature (approximately 23 ° C.) for 24 hours, and “Shintop UP White” manufactured by the same company was applied thereon with a roller at 200 g / m 2.²And dried at room temperature (about 23 ° C.) for 24 hours to form a cured coating film.
[0104]
Next, the photocatalyst paint 1 prepared in the above Formulation Example 1 was sprayed at 10 g / m.²It painted so that it might become. According to the result of examining the physical properties of the coating film simultaneously formed on the quartz plate, the film thickness was 2 μm, the light transmittance at a wavelength of 500 nm was 84%, and the ultraviolet light blocking rate at a wavelength of 320 nm was 99%. . The coated product obtained by coating the base material with the photocatalytic paint 1 in this way has no abnormality in the appearance of the coating film after 4000 hours of sunshine weatherometer (weather resistance tester), and has a cross-cut tape peel test. The result of the adhesion test was also good.
[0105]
<Example 2>
Zinc oxide dispersed in isopropyl alcohol was added to the components of Formulation Example 1 shown in Table 3 so that the resin: titanium oxide: zinc oxide = 70: 10: 20 in solid content ratio. In the same manner as in Example 1, except that a photocatalytic paint was obtained, a coated article was prepared by applying a photocatalytic paint to a substrate. As a result of examining the physical properties of the coating films simultaneously formed on the quartz plate in the same manner as described above, the film thickness was 2 μm, the light transmittance at a wavelength of 500 nm was 87%, and the ultraviolet light blocking rate at a wavelength of 320 nm was 98%. The coated product did not have any abnormality in the appearance of the coating film after a 4,000-hour test with a sunshine weatherometer (weather resistance tester), and the result of the adhesion test by the cross-cut tape peeling test was good.
[0106]
<Example 3>
Cerium oxide dispersed in isopropyl alcohol was added to the components of Formulation Example 1 shown in Table 3 so that the solid content ratio was resin: titanium oxide: cerium oxide = 70: 10: 20. In the same manner as in Example 1, except that a photocatalytic paint was obtained, a coated article was prepared by applying a photocatalytic paint to a substrate. In the same manner as described above, according to the result of examining the physical properties of the coating films simultaneously formed on the quartz plate, the film thickness was 2 μm, the light transmittance at a wavelength of 500 nm was 89%, and the ultraviolet ray blocking rate at a wavelength of 320 nm was 95%. The coated product did not have any abnormality in the appearance of the coating film after a 4,000-hour test with a sunshine weatherometer (weather resistance tester), and the result of the adhesion test by the cross-cut tape peeling test was good.
[0107]
<Example 4>
With respect to the components of Formulation Example 1 shown in Table 3, zinc oxide dispersed in isopropyl alcohol and silica having a particle size of 300 nm were mixed in a solid content ratio of resin: titanium oxide: zinc oxide: silica = 68: 10: 20: 2. A coated article was prepared by coating the base material with the photocatalytic paint in the same manner as in Example 1, except that the photocatalytic paint was obtained in this manner. In the same manner as described above, according to the result of examining the physical properties of the coating films simultaneously formed on the quartz plate, the film thickness was 2 μm, the light transmittance at a wavelength of 500 nm was 70%, and the ultraviolet cutoff rate at a wavelength of 320 nm was 99%. The coated product did not have any abnormality in the appearance of the coating film after a 4,000-hour test with a sunshine weatherometer (weather resistance tester), and the result of the adhesion test by the cross-cut tape peeling test was good.
[0108]
<Comparative Example 1>
The photocatalytic paint Fressella PS-1000 manufactured by Matsushita Electric Works, Ltd. was sprayed on the base material (coated with a sealer and a white paint on a slate plate) having a coating and cured film prepared in Example 1 by spraying at 5 g / m2.²It painted so that it might become. In addition, when this paint is applied on an organic paint, it is a standard specification to use a protection layer (undercoat) of “Fresella NA”. However, in Comparative Example 1, painting was performed directly without using Fresella NA for comparison. The coated article produced as a comparative example produced chalking in a test with a sunshine weatherometer of 500 hours.
[0109]
As described above, the conventional photocatalytic paint has low weather resistance when the undercoat is not applied, whereas the photocatalytic paint of the present invention has one coat applied without the undercoat, as shown in the above-described embodiment. It was found that good results were obtained even in this case.
[Brief description of the drawings]
FIG. 1A is a cross-sectional view of a base material coated with a photocatalytic paint according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of the base material showing another example coated with the photocatalytic paint.
FIG. 2A is a graph of light transmittance of a coating film made of a photocatalytic paint according to an embodiment of the present invention with respect to light having a wavelength of 500 nm, and FIG. Graph of transmittance.
[Explanation of symbols]
1 Photocatalytic paint
2 Organic substrate
3 Organic paint
4 Base material

Claims (11)

In a photocatalytic coating material which has a photocatalytic function by being applied to the surface of a substrate, the coating film transmits at least 50% of light having a wavelength of 500 nm and blocks 80% or more of light having a wavelength of 320 nm. Photocatalytic paint. The photocatalytic paint according to claim 1, wherein the light transmittance at a wavelength of 500 nm is 70% or more and the light blocking property at 320 nm is 90% or more. The photocatalyst paint according to claim 1, wherein the light transmittance at a wavelength of 500 nm is 75% or more, and the light blocking property at 320 nm is 95% or more. Average composition formula (I): R ² _a SiO _b (OR ¹ ) _c (OH) _d , wherein R ¹ and R ² independently represent the same or different substituted or unsubstituted monovalent hydrocarbon groups. A, b, c and d are numbers satisfying the following relationships: a + 2b + c + d = 4, 0 ≦ a <3, 0 <b <2, 0 <c <4, 0 <d <4, and the weight average molecular weight is polystyrene. The photocatalytic paint according to any one of claims 1 to 3, further comprising an organosiloxane partial hydrolyzate having a conversion of 600 to 5000. The photocatalytic paint according to any one of claims 1 to 4, wherein the coating thickness is 1 to 10 µm. The photocatalyst paint according to any one of claims 1 to 5, wherein the photocatalyst has a particle size of 10 to 30 nm. The photocatalytic paint according to any one of claims 1 to 6, wherein the content of titanium oxide in the solid content is 10 to 50%. The photocatalytic paint according to any one of claims 1 to 7, further comprising at least one of zinc oxide and cerium oxide. The photocatalytic paint according to any one of claims 1 to 8, comprising silica having a particle size of 300 nm or more. Photocatalytic coating according to any one of claims 1 to 9 containing a glycidyl group in R ^2. During R ² (meth) photocatalytic coating according to any one of claims 1 to 10 containing acrylic acid ester.

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