JP7247999B2 - Photocatalyst coated body - Google Patents
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- 239000011941 photocatalyst Substances 0.000 title claims description 195
- 239000002245 particle Substances 0.000 claims description 162
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 54
- 239000008199 coating composition Substances 0.000 claims description 50
- 239000000758 substrate Substances 0.000 claims description 41
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims description 39
- 229910001887 tin oxide Inorganic materials 0.000 claims description 37
- 238000000576 coating method Methods 0.000 claims description 19
- 239000011248 coating agent Substances 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 claims description 11
- 239000011163 secondary particle Substances 0.000 claims description 11
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 claims description 9
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 8
- 239000002904 solvent Substances 0.000 claims description 7
- 238000003795 desorption Methods 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 67
- 239000010408 film Substances 0.000 description 26
- 239000000463 material Substances 0.000 description 24
- 229910002089 NOx Inorganic materials 0.000 description 23
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 17
- 239000007787 solid Substances 0.000 description 17
- 230000001699 photocatalysis Effects 0.000 description 12
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 11
- 239000006185 dispersion Substances 0.000 description 10
- 239000007789 gas Substances 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 239000010409 thin film Substances 0.000 description 8
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 7
- 229910006404 SnO 2 Inorganic materials 0.000 description 7
- 238000013461 design Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 238000007254 oxidation reaction Methods 0.000 description 6
- 238000010422 painting Methods 0.000 description 6
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 6
- 238000011156 evaluation Methods 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- 238000001179 sorption measurement Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000009413 insulation Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 239000003642 reactive oxygen metabolite Substances 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- 239000012298 atmosphere Substances 0.000 description 3
- 239000004566 building material Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 239000005357 flat glass Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- -1 nitrate ions Chemical class 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 150000003254 radicals Chemical class 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- 229920002554 vinyl polymer Polymers 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000004887 air purification Methods 0.000 description 1
- 230000000844 anti-bacterial effect Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004567 concrete Substances 0.000 description 1
- 238000010411 cooking Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000001877 deodorizing effect Effects 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 230000009931 harmful effect Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical class [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
- 238000007146 photocatalysis Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000011176 pooling Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- VEALVRVVWBQVSL-UHFFFAOYSA-N strontium titanate Chemical compound [Sr+2].[O-][Ti]([O-])=O VEALVRVVWBQVSL-UHFFFAOYSA-N 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 229910001930 tungsten oxide Inorganic materials 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Description
本発明は、高い透明性を有し、かつ窒素酸化物（ＮＯｘ）除去性能に優れた光触媒塗装体に関する。 TECHNICAL FIELD The present invention relates to a photocatalyst-coated article having high transparency and excellent nitrogen oxide (NO x ) removal performance.
光触媒の一種である二酸化チタン（ＴｉＯ2）は、光のエネルギーにより励起電子と正孔を生成する。生成された励起電子と正孔は、光触媒表面において、酸素と水分の存在下で、Ｏ２ －、Ｏ－、・ＯＨ（・は不対電子を示しラジカル種であることを意味する）等の活性酸素種を生成する。この活性酸素種が有するラジカルな性質を利用して、大気中の窒素酸化物（ＮＯｘ）を酸化反応に供し、無害な反応物に変化させるＮＯｘ除去（大気浄化）技術が知られている。 Titanium dioxide (TiO 2 ), which is a kind of photocatalyst, generates excited electrons and holes by the energy of light. The generated excited electrons and holes are generated on the surface of the photocatalyst in the presence of oxygen and moisture, such as O 2 − , O − , .OH (. indicates an unpaired electron and means a radical species). Generates reactive oxygen species. NOx removal (air purification) technology is known, which utilizes the radical properties of these reactive oxygen species to subject nitrogen oxides ( NOx ) in the atmosphere to an oxidation reaction and convert them into harmless reactants. .
窒素酸化物が活性酸素種による酸化反応を受ける過程では、例えば一酸化窒素（ＮＯ）が酸化を受け、二酸化窒素（ＮＯ２）が中間生成物として生成される。この二酸化窒素が更に酸化を受け、硝酸イオン（ＮＯ３ －）が最終生成物として生成される。光触媒塗装体を用いた窒素酸化物の除去技術として、ＮＯガスを光触媒塗装体内に存在する光触媒粒子と接触させ、ＮＯガスをＮＯ３ －まで酸化させ、これを水洗する方法が知られている。このため、窒素酸化物の除去性能を高めるには、活性酸素種とＮＯあるいはＮＯ２とを共存させることが必要である。 In the process of oxidation of nitrogen oxides by reactive oxygen species, for example, nitrogen monoxide (NO) is oxidized and nitrogen dioxide (NO 2 ) is produced as an intermediate product. This nitrogen dioxide undergoes further oxidation to produce nitrate ions (NO 3 − ) as the final product. As a technique for removing nitrogen oxides using a photocatalyst-coated body, a method of bringing NO gas into contact with photocatalyst particles present in the photocatalyst-coated body, oxidizing the NO gas to NO 3 - , and washing it with water is known. Therefore, in order to enhance the nitrogen oxide removal performance, it is necessary to coexist with reactive oxygen species and NO or NO 2 .
ＮＯの酸化反応により生成されたＮＯ２は化学的に比較的安定した化合物（ガス）であり、反応の系外に脱離するおそれがあるため、活性酸素種による酸化反応の効率が低下し、結果的にＮＯｘ除去性能が低下するおそれがある。このＮＯ２の離脱を抑制するために、光触媒粒子とともにＮＯ２吸着粒子を光触媒層に添加することが知られている。 NO 2 produced by the oxidation reaction of NO is a chemically relatively stable compound (gas) and may desorb out of the reaction system. As a result, the NOx removal performance may deteriorate. In order to suppress this release of NO 2 , it is known to add NO 2 adsorption particles to the photocatalyst layer together with the photocatalyst particles.
例えば、ＷＯ２０１２／０１４８９３公報（特許文献１）は、ＮＯ２吸着粒子として結晶性ＺｒＯ２粒子を配合することで、光触媒によるＮＯｘ除去性能が向上することを開示している。結晶性ＺｒＯ２粒子は、ＮＯが酸化されて生成された二酸化窒素（ＮＯ２）（ガス）に対する吸着性能が高く、このＮＯ２が光触媒層（反応系）外に脱離するのを抑制し、これを効率良く保持することができる。その結果、その後のＮＯ２が酸化されＮＯ３ －が生成される反応が効率よく行われる。 For example, WO2012/014893 (Patent Document 1) discloses that the NOx removal performance by photocatalysis is improved by blending crystalline ZrO2 particles as NO2 adsorption particles. Crystalline ZrO 2 particles have high adsorption performance for nitrogen dioxide (NO 2 ) (gas) generated by oxidation of NO, suppressing desorption of this NO 2 out of the photocatalyst layer (reaction system), This can be held efficiently. As a result, the subsequent reaction in which NO 2 is oxidized and NO 3 - is produced efficiently.
また、基材上に設けられた光触媒層は、ＮＯｘ除去性能等の光触媒活性を発揮するために光触媒量が多いことが望まれ、その結果ある程度の膜厚があり、光触媒量が多い方が有利であるが、他方で、例えば、透明な基材に設けられる場合には基材の透明性を妨げないものであることが求められる。また基材が透明でない場合であっても、基材表面の色などの意匠に影響を与えないよう、透明性に優れるものであることが望まれる。膜が厚くなることは透明性の点では不利となる場合がある。 In addition, the photocatalyst layer provided on the base material is desired to have a large amount of photocatalyst in order to exhibit photocatalyst activity such as NOx removal performance, and as a result, it is advantageous to have a certain amount of film thickness and a large amount of photocatalyst. However, on the other hand, for example, when it is provided on a transparent substrate, it is required that it does not interfere with the transparency of the substrate. Moreover, even when the substrate is not transparent, it is desired that the transparency is excellent so as not to affect the design such as the color of the substrate surface. A thick film may be disadvantageous in terms of transparency.
特開２０１７－０８１８０７号公報（特許文献２）は、二酸化窒素吸着粒子としてのＺｒＯ２粒子に加え、酸化スズ粒子を配合することで、ＮＯｘ除去性能を発現する膜厚であっても、高い透明性を確保できるとしている。例えばこの特許文献２の開示の組成において、ＮＯｘ除去能として０．５μｍｏｌを超える塗膜の厚みを与えても、塗膜外観の良好性（例えば、ヘイズ１０％以下）を確保できるとしている。 Japanese Patent Application Laid-Open No. 2017-081807 (Patent Document 2) discloses that by blending tin oxide particles in addition to ZrO2 particles as nitrogen dioxide adsorption particles, high transparency can be obtained even with a film thickness that exhibits NOx removal performance. It is said that the quality can be ensured. For example, in the composition disclosed in Patent Document 2, even if the thickness of the coating film exceeds 0.5 μmol as the NOx removal ability, good coating film appearance (for example, haze of 10% or less) can be ensured.
一方で、光触媒層が形成される基材は、その用途に応じて意匠や質感を付与するためにその表面が平滑ではないことがある。表面が平滑な基材上に光触媒層を形成する際、コーティング液をレベリング処理することが知られているが、表面に凹凸が付された基材にあっては、レベリング剤では均一な厚さの光触媒層を実現できないことがある。凹凸を有する基材の表面に光触媒層を形成する場合、例えば、塗布前に基材を予熱し、塗布後直ぐに液を乾燥させる方法や、スプレーを使用して凸部および凹部双方に均一な光触媒層の塗膜を得る方法などが行われているが、膜厚は薄くなる傾向がある。そのため、薄い膜厚であっても、ＮＯｘ除去能等の光触媒活性に優れた光触媒層が求められる。 On the other hand, the substrate on which the photocatalyst layer is formed may not have a smooth surface in order to impart a design or texture depending on the application. When forming a photocatalyst layer on a substrate with a smooth surface, it is known to apply a leveling treatment to the coating solution. of the photocatalyst layer may not be realized. When forming a photocatalyst layer on the surface of a substrate having unevenness, for example, a method of preheating the substrate before coating and drying the liquid immediately after coating, or using a spray to apply a uniform photocatalyst to both the convex and concave portions A method for obtaining a coating film of a layer has been used, but the film thickness tends to be thin. Therefore, there is a demand for a photocatalyst layer that is excellent in photocatalytic activity such as NOx removal ability even if it is thin.
以上のように、種々の基材、とりわけその表面が平滑ではない基材においても、高い光触媒活性を確保しながら、透明に優れた光触媒層が依然として求められているといえる。 As described above, it can be said that there is still a demand for a photocatalyst layer excellent in transparency while ensuring high photocatalytic activity even on various substrates, especially substrates with uneven surfaces.
本発明者らは、今般、ＮＯｘ除去能等の光触媒活性に優れた光触媒層の新たな組成および構成を見出した。その結果、高い透明性を確保でき、かつ場合により比較的薄い膜厚としても、十分な光触媒活性を備える光触媒層を形成することができるとの知見を得た。本発明はこの知見に基づくものである。 The present inventors have recently discovered a new composition and configuration of a photocatalyst layer that exhibits excellent photocatalytic activity such as NOx removal ability. As a result, the inventors have found that a photocatalyst layer having sufficient photocatalytic activity can be formed while ensuring high transparency and, in some cases, with a relatively thin film thickness. The present invention is based on this finding.
従って、本発明は、高い透明性と、優れたＮＯｘ除去能等の光触媒活性を有する光触媒層を備えた光触媒塗装体を提供することを目的とする。 Accordingly, an object of the present invention is to provide a photocatalyst-coated article having a photocatalyst layer having high transparency and photocatalyst activity such as excellent NOx removal ability.
そして、本発明による光触媒塗装体は、
基材と、当該基材の表面に設けられた光触媒層とを少なくとも備えてなる光触媒塗装体であって、
前記光触媒層が、光触媒粒子と、４価の正方晶からなる酸化スズ粒子と、ジルコニア粒子とを少なくとも含有し、
前記光触媒粒子の平均二次粒子径が、０ｎｍを超え２０ｎｍ未満であり、
前記光触媒粒子の含有量が、前記光触媒粒子と、前記酸化スズ粒子と、前記ジルコニア粒子との合計に対して、３５質量％以上５０質量％以下であり、
前記光触媒粒子の含有量に対する前記酸化スズ粒子の含有量の比（酸化スズ粒子／光触媒粒子）が、０．０５以上０．５以下であり、
前記光触媒層の平均膜厚が、６０ｎｍ以上２６０ｎｍ以下である
ことを特徴とする。
And the photocatalyst-coated body according to the present invention is
A photocatalyst-coated body comprising at least a substrate and a photocatalyst layer provided on the surface of the substrate,
The photocatalyst layer contains at least photocatalyst particles, tetravalent tetragonal tin oxide particles, and zirconia particles,
The average secondary particle size of the photocatalyst particles is more than 0 nm and less than 20 nm,
The content of the photocatalyst particles is 35% by mass or more and 50% by mass or less with respect to the total of the photocatalyst particles, the tin oxide particles, and the zirconia particles,
The ratio of the content of the tin oxide particles to the content of the photocatalyst particles (tin oxide particles/photocatalyst particles) is 0.05 or more and 0.5 or less,
The photocatalyst layer has an average film thickness of 60 nm or more and 260 nm or less.
本発明によれば、高い透明性と、優れたＮＯｘ除去能等の光触媒活性を有する光触媒層を備えたよる光触媒塗装体が提供される。特に、高い透明性を確保可能な薄い膜厚でありながら、優れた光触媒活性、特にＮＯｘ除去性能を発揮することができる光触媒層を備えた光触媒塗装体が提供できる。また、光触媒層が薄い膜厚であることから、そのコストを抑制できるとの利点も得られる。 ADVANTAGE OF THE INVENTION According to this invention, the photocatalyst coating body provided with the photocatalyst layer which has photocatalyst activity, such as high transparency and excellent NOx removal ability, is provided. In particular, it is possible to provide a photocatalyst-coated body having a photocatalyst layer capable of exhibiting excellent photocatalyst activity, particularly NOx removal performance, while maintaining a thin film thickness that can ensure high transparency. In addition, since the photocatalyst layer has a small film thickness, there is an advantage that the cost can be suppressed.
光触媒塗装体
本発明による光触媒塗装体は、基材と、その表面に設けられた光触媒層とを備えてなり、そして前記した特許文献２（特開２０１７－０８１８０７号公報）に記載の光触媒塗装体と、その基本構成において共通するものである。したがって、本明細書の記載及び本発明と矛盾しない範囲において、特許文献２の記載は本明細書の開示の一部とされ、本発明の説明、理解において参照される。
Photocatalyst-coated body The photocatalyst-coated body according to the present invention comprises a substrate and a photocatalyst layer provided on the surface thereof, and is described in Patent Document 2 (Japanese Patent Application Laid-Open No. 2017-081807). and the basic configuration thereof. Therefore, to the extent not inconsistent with the description of the present specification and the present invention, the description of Patent Document 2 is considered part of the disclosure of the present specification, and is referred to in the description and understanding of the present invention.
光触媒層
光触媒層は、光触媒粒子と、４価の正方晶からなる酸化スズ粒子と、ジルコニア粒子とを少なくとも含有してなる。さらに、これら粒子は、以下に説明するそれぞれの物性及び組成とされることで、優れた光触媒活性を発揮する。なお、本発明は、透明性および光触媒活性を阻害しない範囲において、これら３種の粒子成分以外の成分を含む態様を排除するものではない。
Photocatalyst Layer The photocatalyst layer contains at least photocatalyst particles, tetravalent tetravalent tin oxide particles, and zirconia particles. Furthermore, these particles exhibit excellent photocatalytic activity by having the respective physical properties and compositions described below. It should be noted that the present invention does not exclude embodiments containing components other than these three types of particle components as long as they do not impair transparency and photocatalytic activity.
光触媒粒子
本発明による光触媒塗装体の光触媒層に含まれる光触媒粒子は、抗菌機能、脱臭機能、有害ガス除去機能、親水性機能などの光触媒機能を発揮するのに十分なバンド・ギャップを有する半導体粒子である。
Photocatalyst Particles The photocatalyst particles contained in the photocatalyst layer of the photocatalyst-coated body according to the present invention are semiconductor particles having a sufficient band gap to exhibit photocatalyst functions such as antibacterial, deodorizing, harmful gas removing, and hydrophilic functions. is.
本発明において、光触媒粒子の好ましい例としては、例えば、アナターゼ型酸化チタン、ルチル型酸化チタン、ブルッカイト型酸化チタンなどの酸化チタン、酸化亜鉛、酸化錫、チタン酸ストロンチウム、酸化タングステンなど金属酸化物の粒子が挙げられる。光触媒粒子は、より好ましくは酸化チタン粒子であり、さらにより好ましくはアナターゼ型酸化チタン粒子である。 In the present invention, preferred examples of the photocatalyst particles include titanium oxides such as anatase-type titanium oxide, rutile-type titanium oxide, and brookite-type titanium oxide, and metal oxides such as zinc oxide, tin oxide, strontium titanate, and tungsten oxide. particles. The photocatalyst particles are more preferably titanium oxide particles, and even more preferably anatase-type titanium oxide particles.
本発明において、光触媒粒子は、０ｎｍを超え２０ｎｍ未満の平均二次粒子径を有する。この範囲は従来の光触媒層を形成する光触媒粒子と対比すると比較的小粒径である。平均二次粒子径がこの範囲にあることで、光触媒層の光触媒活性が高くなる、すなわちＮＯｘ除去性能が向上する。さらに、光触媒層内に光触媒粒子間の空隙を形成する場合に、光触媒活性を高めるために好適な空隙径に制御し易くなるとの利点が得られる。光触媒粒子の平均二次粒子径は、好ましいその下限は５ｎｍ以上であり、好ましいその上限は１５ｎｍ以下である。 In the present invention, the photocatalyst particles have an average secondary particle size of more than 0 nm and less than 20 nm. This range is a relatively small particle size as compared with photocatalyst particles forming a conventional photocatalyst layer. When the average secondary particle size is within this range, the photocatalytic activity of the photocatalyst layer is increased, that is, the NOx removal performance is improved. Furthermore, when forming voids between photocatalyst particles in the photocatalyst layer, there is an advantage that the void diameter can be easily controlled to be suitable for enhancing the photocatalytic activity. The preferred lower limit of the average secondary particle size of the photocatalyst particles is 5 nm or more, and the preferred upper limit thereof is 15 nm or less.
本明細書において、平均二次粒子径とは、走査型電子顕微鏡により２０万倍の視野に入る任意の１００個の粒子の長さを測定した個数平均値として算出されるものを意味する。また、本発明において、光触媒粒子の形状としては真球が好ましいが、略円形や楕円形でもよい。真球でない場合の光触媒粒子の平均二次粒子径は、（長径＋短径）／２として略算出される。 In the present specification, the average secondary particle diameter is calculated as a number average value obtained by measuring the length of arbitrary 100 particles entering a 200,000-fold field of view with a scanning electron microscope. In the present invention, the shape of the photocatalyst particles is preferably spherical, but may be substantially circular or elliptical. The average secondary particle size of the photocatalyst particles when they are not truly spherical is approximately calculated as (major axis + minor axis)/2.
４価の正方晶からなる酸化スズ粒子
本発明による光触媒塗装体の光触媒層に含まれる４価の正方晶からなる酸化スズ粒子は、光触媒粒子とともに光触媒層に存在することで、光触媒塗装体の有機物分解性能およびＮＯｘ除去性能の双方を向上させる。４価の正方晶からなる酸化スズを含有することで、とりわけＮＯをＮＯ２に酸化する反応の効率を向上させる。
Tetravalent tetragonal tin oxide particles
The tetravalent tetravalent tin oxide particles contained in the photocatalyst layer of the photocatalyst-coated body according to the present invention are present in the photocatalyst layer together with the photocatalyst particles, thereby improving both the organic substance decomposition performance and the NO x removal performance of the photocatalyst-coated body. Improve. The inclusion of tetravalent tetragonal tin oxide improves the efficiency of the reaction, inter alia, the oxidation of NO to NO2 .
４価の正方晶からなる酸化スズ粒子の結晶子サイズは、例えば、１ｎｍ以上４ｎｍ以下であることが好ましい。結晶子サイズがこの範囲にあることで、光触媒粒子と４価の正方晶からなる酸化スズ粒子との光触媒層中における接触確率が増加し、電荷分離効果を高めることができる。なお、結晶子サイズは、例えば、Ｘ線回折におけるバックグランドを除くパターンフィッティング処理後に、２θ＝２５～２８°付近の（１１０）面の回折ピークを利用してシェラー式により算出される。 The crystallite size of the tetravalent tetragonal tin oxide particles is preferably, for example, 1 nm or more and 4 nm or less. When the crystallite size is within this range, the probability of contact between the photocatalyst particles and the tin oxide particles composed of a tetravalent tetragonal crystal in the photocatalyst layer increases, and the charge separation effect can be enhanced. The crystallite size is calculated, for example, by Scherrer's formula using the diffraction peak of the (110) plane near 2θ=25 to 28° after pattern fitting processing to remove the background in X-ray diffraction.
ジルコニア粒子
本発明による光触媒塗装体の光触媒層に含まれるジルコニア粒子は、ＮＯがＮＯ２に酸化されて生成された二酸化窒素（ガス）に対する吸着性能が高い。ジルコニア粒子は、生成されたＮＯ２が光触媒層（反応系）外に脱離するのを抑制し、効率良く保持することができる。二酸化窒素（ガス）は酸性であるため、その表面に塩基性サイトを有するジルコニア粒子を含むことにより、光触媒層はより多くの二酸化窒素を吸着することができる。
Zirconia Particles The zirconia particles contained in the photocatalyst layer of the photocatalyst-coated body according to the present invention have a high adsorption performance for nitrogen dioxide (gas) produced by oxidizing NO to NO 2 . The zirconia particles can suppress desorption of the generated NO 2 to the outside of the photocatalyst layer (reaction system) and retain it efficiently. Since nitrogen dioxide (gas) is acidic, the photocatalyst layer can adsorb more nitrogen dioxide by including zirconia particles having basic sites on its surface.
ジルコニア粒子の形状は、球状、またはアスペクト比が１より大きい楕円状、長方形、もしくは針状のいずれであってもよい。ジルコニア粒子は、光触媒層内において、略均一に分散して配置されていることが好ましい。 The shape of the zirconia particles may be spherical, oval with an aspect ratio greater than 1, rectangular, or acicular. It is preferable that the zirconia particles are substantially uniformly dispersed and arranged in the photocatalyst layer.
光触媒層中の光触媒粒子の含有量
本発明において、光触媒粒子の含有量は、光触媒層全体に含まれる光触媒粒子、４価の正方晶からなる酸化スズ粒子、及びジルコニア粒子の合計の濃度を１００質量％としたとき、３５質量％以上５０質量％以下である。本発明の好ましい態様によれば、光触媒粒子の含有量の下限は、好ましくは４０重量％以上であり、より好ましくは４４重量％以上である。光触媒粒子の含有量がこの範囲にあることで、良好な光触媒活性が実現できる。本発明にあっては、ＮＯがＮＯ２に酸化される反応、そしてＮＯ２が酸化されＮＯ３
－が生成される反応のいずれの反応効率も高めることができると考えられる。
また、光触媒塗膜体の透明性を考慮すると、光触媒粒子の含有量が多いほど透明性が損なわれる傾向があるため、本発明において、光触媒粒子の含有量の上限を５０質量％以下とすることで、良好な光触媒活性の発現とともに良好な透明性の確保が可能とされる。
Content of photocatalyst particles in the photocatalyst layer In the present invention, the content of photocatalyst particles is defined as the total concentration of photocatalyst particles, tetravalent tetragonal tin oxide particles, and zirconia particles contained in the entire photocatalyst layer, which is 100 mass. %, it is 35% by mass or more and 50% by mass or less. According to a preferred embodiment of the present invention, the lower limit of the content of photocatalyst particles is preferably 40% by weight or more, more preferably 44% by weight or more. When the content of the photocatalyst particles is within this range, good photocatalytic activity can be achieved. In the present invention, it is believed that the reaction efficiency of both the reaction in which NO is oxidized to NO 2 and the reaction in which NO 2 is oxidized to produce NO 3 − can be enhanced.
In addition, considering the transparency of the photocatalyst coated body, the more the content of the photocatalyst particles, the more the transparency tends to be impaired. Therefore, it is possible to exhibit good photocatalytic activity and ensure good transparency.
光触媒層中の酸化スズ粒子の光触媒粒子に対する含有比
本発明において、光触媒層における４価の正方晶からなる酸化スズ粒子の含有量は、光触媒層における光触媒粒子の含有量に対する質量比（酸化スズ粒子／光触媒粒子）で、０．０５以上０．５以下である。酸化スズ粒子／光触媒粒子は、より好ましくは、０．０５以上０．１以下である。本発明にあって、４価の正方晶からなる酸化スズ粒子と光触媒粒子とをこの割合で共存させ、かつ光触媒粒子を上記量とすることで良好な光触媒活性が得られる。本発明にあっては、４価の正方晶からなる酸化スズ粒子と光触媒粒子との割合が、ＮＯをＮＯ２に酸化する反応をより促進するものと考えられる。しかしこの説明はあくまで仮定であって、本発明はこれに限定されるものではない。
Content ratio of tin oxide particles to photocatalyst particles in the photocatalyst layer In the present invention, the content of tin oxide particles consisting of a tetravalent tetragonal crystal in the photocatalyst layer is the mass ratio (tin oxide particles) to the content of photocatalyst particles in the photocatalyst layer. /photocatalyst particles) and is 0.05 or more and 0.5 or less. The ratio of tin oxide particles/photocatalyst particles is more preferably 0.05 or more and 0.1 or less. In the present invention, good photocatalytic activity can be obtained by allowing the tetravalent tetravalent tin oxide particles and the photocatalyst particles to coexist at this ratio and by adjusting the amount of the photocatalyst particles to the above amount. In the present invention, it is considered that the ratio of the tetravalent tetravalent tin oxide particles and the photocatalyst particles promotes the reaction of oxidizing NO to NO 2 . However, this explanation is only an assumption, and the present invention is not limited to this.
光触媒層の膜厚
本発明において、光触媒層の平均膜厚は６０ｎｍ以上２６０ｎｍ以下である。本発明の好ましい態様によれば、その下限は８０ｎｍ以上であり、より好ましくは１００ｎｍ以上であり、その上限は２３０ｎｍ以下であり、より好ましくは２００ｎｍ以下である。上述したとおり、光触媒粒子、４価の正方晶からなる酸化スズ粒子、および前記ジルコニア粒子を特定の量比で含むことにより、高い透明性と優れたＮＯｘ除去性能を両立した薄い膜厚の光触媒層を得ることができる。
Film thickness of photocatalyst layer In the present invention, the average film thickness of the photocatalyst layer is 60 nm or more and 260 nm or less. According to a preferred embodiment of the present invention, the lower limit is 80 nm or more, more preferably 100 nm or more, and the upper limit is 230 nm or less, more preferably 200 nm or less. As described above, photocatalyst particles, tetravalent tetravalent tin oxide particles, and zirconia particles are contained in a specific amount ratio, so that a thin film photocatalyst that achieves both high transparency and excellent NO x removal performance. You can get layers.
本発明による光触媒塗装体は、高い透明性を確保可能な薄い膜厚でありながら、優れたＮＯｘ除去性能をも発揮し、本発明において透明性はヘイズを指標として示すことができる。本発明の好ましい態様によれば、光触媒塗装体の表面のヘイズは１０％以下である。 The photocatalyst-coated body according to the present invention has a thin film thickness that can ensure high transparency, yet exhibits excellent NOx removal performance. In the present invention, haze can be used as an indicator of transparency. According to a preferred embodiment of the present invention, the surface haze of the photocatalyst-coated body is 10% or less.
本発明の好ましい態様によれば、光触媒塗装体は、光触媒層の平均膜厚が１００ｎｍ以上２００ｎｍ以下という厚さにおいて、ＪＩＳ Ｒ１７０１－１に記載の方法により行い得られたＮＯｘ除去性能［ΔＮＯｘ（μｍｏｌ）］において０．５０μｍｏｌであり、好ましくは０．７０μｍｏｌを超える高いＮｏｘ除去性能を有する。 According to a preferred embodiment of the present invention, the photocatalyst-coated body has an average film thickness of the photocatalyst layer of 100 nm or more and 200 nm or less, and the NO x removal performance [ΔNO x (μmol)] is 0.50 μmol, and preferably has a high Nox removal performance exceeding 0.70 μmol.
本発明において、光触媒層に含有される光触媒粒子、４価の正方晶からなる酸化スズ粒子、およびジルコニア粒子の、基材の単位面積当たりの合計重量（「固形分量」ということもある）は、好ましくは０．１３ｇ／ｍ２以上０．５１ｇ／ｍ２以下、より好ましくは０．１８ｇ／ｍ２以上０．５１ｇ／ｍ２以下、さらにより好ましくは０．２３ｇ／ｍ２以上０．３５ｇ／ｍ２以下である。これら３種の粒子を上記範囲の固形分量で含む光触媒層は、高い透明性を確保可能な薄い膜厚でありながら、優れたＮＯｘ除去性能をも発揮することができる。 In the present invention, the total weight per unit area of the substrate of the photocatalyst particles, the tetravalent tetravalent tin oxide particles, and the zirconia particles contained in the photocatalyst layer (also referred to as "solid content") is Preferably 0.13 g/m 2 or more and 0.51 g/m 2 or less, more preferably 0.18 g/m 2 or more and 0.51 g/m 2 or less, still more preferably 0.23 g/m 2 or more and 0.35 g/m 2 or more m2 or less. A photocatalyst layer containing these three types of particles in a solid content amount within the above range can exhibit excellent NOx removal performance while having a thin film thickness that can ensure high transparency.
基材
本発明において、基材はその上に光触媒層を形成可能な材料であれば無機材料、有機材料を問わず種々の材料であってよく、その形状も限定されない。材料の観点からみた基材の好ましい例としては、金属、セラミック、ガラス、プラスチック、ゴム、石、セメント、コンクリ－ト、繊維、布帛、木、紙、それらの組合せ、それらの積層体、それらの表面に少なくとも一層の被膜を有するものが挙げられる。用途の観点からみた基材の好ましい例としては、建材、建物外装、窓枠、窓ガラス、構造部材、乗物の外装及び塗装、機械装置や物品の外装、防塵カバ－及び塗装、交通標識、各種表示装置、広告塔、道路用遮音壁、鉄道用遮音壁、橋梁、ガ－ドレ－ルの外装及び塗装、トンネル内装及び塗装、碍子、太陽電池カバ－、太陽熱温水器集熱カバ－、ビニ－ルハウス、車両用照明灯のカバ－、屋外用照明器具、台及び上記物品表面に貼着させるためのフィルム、シート、シール等といった外装材が挙げられる。
Substrate In the present invention, the substrate may be any material, whether inorganic or organic, as long as it is a material on which a photocatalyst layer can be formed, and its shape is not limited. Preferred examples of substrates from the viewpoint of materials include metals, ceramics, glass, plastics, rubber, stone, cement, concrete, fibers, fabrics, wood, paper, combinations thereof, laminates thereof, and laminates thereof. Examples include those having at least one layer of coating on the surface. Preferable examples of base materials from the viewpoint of use include building materials, building exteriors, window frames, window glass, structural members, exteriors and coatings of vehicles, exteriors of mechanical devices and articles, dustproof covers and coatings, traffic signs, and various other materials. Display devices, advertising towers, sound insulation walls for roads, sound insulation walls for railways, bridges, exterior and painting of guardrails, interior and painting of tunnels, insulators, solar cell covers, solar water heater heat collection covers, vinyl houses, Exterior materials such as covers for vehicle lamps, outdoor lighting fixtures, pedestals, and films, sheets, seals, etc. to be adhered to the surfaces of the above-mentioned articles are exemplified.
本発明においては、その表面が有機物質を含んでなる基材を用いることができる。そのような基材としては、例えば、有機物を含む樹脂、有機物を含む樹脂を含有する塗装を表面に施した塗装体、有機物を含む樹脂を含有するフィルム等を表面に積層した積層体などが挙げられる。適用可能な基材を用途でいえば、金属塗装板、塩ビ鋼板等の金属積層板、窯業系化粧板、樹脂建材等の建材、建物外装、建物内装、窓枠、窓ガラス、構造部材、乗物の外装及び塗装、機械装置や物品の外装、防塵カバ－及び塗装、交通標識、各種表示装置、広告塔、道路用遮音壁、鉄道用遮音壁、橋梁、ガ－ドレ－ルの外装及び塗装、トンネル内装及び塗装、碍子、太陽電池カバ－、太陽熱温水器集熱カバ－、ビニ－ルハウス、車両用照明灯のカバ－、住宅設備、便器、浴槽、洗面台、照明器具、照明カバ－、台所用品、食器、食器洗浄器、食器乾燥器、流し、調理レンジ、キッチンフ－ド、換気扇等が挙げられる。 In the present invention, a substrate whose surface contains an organic substance can be used. Examples of such a substrate include a resin containing an organic substance, a coated body having a surface coated with a coating containing a resin containing an organic substance, a laminate having a film containing a resin containing an organic substance laminated on the surface, and the like. be done. In terms of applications, applicable base materials include metal coated plates, metal laminates such as PVC steel plates, ceramic decorative boards, building materials such as resin building materials, building exteriors, building interiors, window frames, window glass, structural members, and vehicles. Exterior and painting of machinery equipment and articles, dustproof covers and painting, traffic signs, various display devices, advertising towers, noise insulation walls for roads, noise insulation walls for railways, bridges, exterior and painting of guardrails, tunnel interiors And painting, insulators, solar battery covers, solar water heater heat collection covers, vinyl houses, vehicle lighting covers, housing equipment, toilet bowls, bathtubs, washstands, lighting fixtures, lighting covers, kitchen utensils, Examples include tableware, dishwashers, dish dryers, sinks, cooking ranges, kitchen hoods, ventilation fans, and the like.
本発明の好ましい態様によれば、基材は、例えば住宅向け外壁タイルのような表面に意匠や質感を有するものである。表面に意匠や質感を有する基材として、例えば、レベリング剤の効果を期待しにくい又は予熱処理されることがある凹凸形状の表面を有する基材が挙げられる。本発明にあっては、これら表面に意匠や質感を有する基材の上に、高い透明性を確保可能な薄い膜厚でありながら、優れたＮＯｘ除去性能を発揮することができる光触媒層を設けることが可能である。すなわち、基材の意匠や質感を有効に利用することができ、光触媒塗装体全体として高い透明性を確保しつつ、優れたＮＯｘ除去性能を発現することができる。 According to a preferred embodiment of the present invention, the base material has a design or texture on its surface, such as an exterior wall tile for housing. Substrates having a design or texture on the surface include, for example, substrates having an uneven surface on which the effect of a leveling agent is unlikely to be expected or which may be preheated. In the present invention, a photocatalyst layer capable of exhibiting excellent NOx removal performance while having a thin film thickness that can ensure high transparency is formed on the base material having a design and texture on the surface. can be provided. That is, the design and texture of the base material can be effectively utilized, and excellent NOx removal performance can be exhibited while ensuring high transparency of the photocatalyst-coated body as a whole.
光触媒塗装体の製造方法
本発明による光触媒塗装体は、例えば以下の方法により製造することができる。すなわち、本発明による光触媒塗装体の製造方法は、
基材を用意する工程と、
この基材の表面に、光触媒粒子と、４価の正方晶からなる酸化スズ粒子と、ジルコニア粒子と、溶媒とを含有するコーティング組成物を塗布して光触媒層を形成する工程とを少なくとも含む。
Manufacturing method of photocatalyst-coated body The photocatalyst-coated body according to the present invention can be manufactured, for example, by the following method. That is, the method for producing a photocatalyst-coated body according to the present invention is
providing a base material;
At least a step of applying a coating composition containing photocatalyst particles, tetravalent tetravalent tin oxide particles, zirconia particles, and a solvent to the surface of the substrate to form a photocatalyst layer.
本発明において、コーティング組成物に含まれる光触媒粒子、前記４価の正方晶からなる酸化スズ粒子、および前記ジルコニア粒子の合計濃度（「固形分濃度」ということもある）は、好ましくは０．５質量％以上１．７質量％以下、より好ましくは０．７質量％以上１．７質量％以下、さらにより好ましくは０．８質量％以上１．２質量％以下である。これら３種の粒子を上記範囲の固形分濃度で含むコーティング組成物を塗布することにより、膜厚が薄く、高い透明性を有する光触媒層を得ることができる。 In the present invention, the total concentration of the photocatalyst particles, the tetravalent tetravalent tin oxide particles, and the zirconia particles contained in the coating composition (also referred to as “solid content concentration”) is preferably 0.5. % by mass or more and 1.7% by mass or less, more preferably 0.7% by mass or more and 1.7% by mass or less, and even more preferably 0.8% by mass or more and 1.2% by mass or less. A photocatalyst layer having a thin film thickness and high transparency can be obtained by applying a coating composition containing these three types of particles at a solid content concentration within the above range.
本発明において、コーティング組成物の基材表面の単位面積当たりの塗布量は、２６ｇ／ｍ２以上３２ｇ／ｍ２以下であることが好ましい。光触媒粒子、前記４価の正方晶からなる酸化スズ粒子、および前記ジルコニア粒子を上記範囲の固形分濃度で含むコーティング組成物を上記範囲の塗布量で基材に塗布することにより、高い透明性を確保可能な薄い膜厚でありながら、優れたＮＯｘ除去性能をも発揮する光触媒層を得ることができる。 In the present invention, the coating amount per unit area of the substrate surface of the coating composition is preferably 26 g/m 2 or more and 32 g/m 2 or less. By applying the coating composition containing the photocatalyst particles, the tetravalent tetravalent tin oxide particles, and the zirconia particles at the solid content concentration in the above range to the substrate in the above range, high transparency can be obtained. It is possible to obtain a photocatalyst layer that exhibits excellent NOx removal performance while maintaining a thin film thickness that can be secured.
本発明において、基材の表面にコーティング組成物を塗布した後、塗布されたコーティング組成物の塗膜を焼成して光触媒層を形成することが好ましい。塗膜を焼成することにより、より強く基材に光触媒層を固定でき、耐久性、耐候性に優れた光触媒塗装体が得られる。 In the present invention, it is preferable to form a photocatalyst layer by applying the coating composition to the surface of the substrate and then baking the applied coating composition. By baking the coating film, the photocatalyst layer can be more strongly fixed to the base material, and a photocatalyst-coated body excellent in durability and weather resistance can be obtained.
本発明において、基材は予熱処理されたものであってもよい。とりわけ凹凸形状を有する基材を予め温めておくことにより、コーティング組成物を塗布した後、当該組成物が凹部にたまったり或いはタレたりするのを防止することができる。 In the present invention, the substrate may be preheated. In particular, by preheating the substrate having the irregular shape, it is possible to prevent the composition from pooling in the concave portions or dripping after the coating composition has been applied.
本発明において、基材表面へのコーティング組成物の塗布方法は、スプレー塗装が好ましい。とりわけ表面が凹凸形状の基材に対しては、スプレー塗装を用いることで、凸部および凹部双方において均一な光触媒層の塗膜を得ることができる。その結果、凹凸形状の表面を有する基材に、高い透明性を確保できる薄い膜厚でありながら、十分なＮＯｘ除去量も確保可能な光触媒層を形成することができる。 In the present invention, the method of applying the coating composition to the substrate surface is preferably spray coating. In particular, for a base material having an uneven surface, spray coating can be used to obtain a uniform photocatalyst coating film on both the convex portions and the concave portions. As a result, it is possible to form a photocatalyst layer on a base material having an uneven surface, which is thin enough to ensure high transparency and which can also ensure a sufficient amount of NO x removal.
本発明を以下の実施例により具体的に説明するが、本発明はこれら実施例に限定されて解釈されるものではない。 The present invention will be specifically described by the following examples, but the present invention should not be construed as being limited to these examples.
コーティング組成物の調製
＜コーティング組成物１～７＞
粒子成分として、ＴｉＯ２粒子、４価の正方晶からなる酸化スズ粒子（以下、単にＳｎＯ２粒子と称する場合もある）、およびＺｒＯ２粒子を表１に示す割合で混合した。
ＴｉＯ２粒子として、アナターゼ型チタニア水分散体Ａを用いた。分散体ＡのＴｉＯ２粒子の平均二次粒子径は１０ｎｍであった。
ＳｎＯ２粒子として、４価の正方晶からなる酸化スズ粒子水分散体を用いた。ＳｎＯ２粒子の平均二次粒子径は８ｎｍであった。
ＺｒＯ２粒子として、非晶質ジルコニア粒子水分散体を用いた。ＺｒＯ２粒子の平均二次粒子径は２０ｎｍであった。
これら粒子成分に、溶媒として水を添加し混合してコーティング組成物１～７を調製した。コーティング組成物１～３の固形分濃度は０．８質量％、コーティング組成物４～７の固形分濃度は１．２質量％とした。
Preparation of coating composition <Coating compositions 1 to 7>
As particle components, TiO 2 particles, tetravalent tetragonal tin oxide particles (hereinafter sometimes simply referred to as SnO 2 particles), and ZrO 2 particles were mixed at the ratios shown in Table 1.
Anatase titania aqueous dispersion A was used as TiO 2 particles. The average secondary particle size of the TiO2 particles of Dispersion A was 10 nm.
As the SnO 2 particles, an aqueous dispersion of tetravalent tetravalent tin oxide particles was used. The average secondary particle size of SnO2 particles was 8 nm.
Amorphous zirconia particle water dispersion was used as ZrO2 particles. The average secondary particle size of ZrO2 particles was 20 nm.
Coating compositions 1 to 7 were prepared by adding water as a solvent to these particle components and mixing them. The solid content concentration of coating compositions 1 to 3 was 0.8% by mass, and the solid content concentration of coating compositions 4 to 7 was 1.2% by mass.
＜コーティング組成物８～１５＞
粒子成分として、ＴｉＯ２粒子、ＳｎＯ２粒子、およびＺｒＯ２粒子を表１に示す割合で混合した。使用した各粒子成分の分散体はコーティング組成物１～７と同じとした。これら粒子成分に、溶媒として水を添加し混合してコーティング組成物８～１５を調製した。
コーティング組成物１０の固形分濃度は０．４質量％、コーティング組成物１１の固形分濃度は１．８質量％、コーティング組成物１２の固形分濃度は０．８質量％、コーティング組成物１４の固形分濃度は０．６質量％、コーティング組成物８、９、１３、１５の固形分濃度は１．２質量％とした。
<Coating Compositions 8 to 15>
As particle components, TiO 2 particles, SnO 2 particles, and ZrO 2 particles were mixed in the proportions shown in Table 1. The dispersion of each particle component used was the same as for coating compositions 1-7. Coating compositions 8 to 15 were prepared by adding water as a solvent to these particle components and mixing them.
The solid content concentration of the coating composition 10 is 0.4% by mass, the solid content concentration of the coating composition 11 is 1.8% by mass, the solid content concentration of the coating composition 12 is 0.8% by mass, and the coating composition 14 is The solid content concentration was 0.6% by mass, and the solid content concentration of Coating Compositions 8, 9, 13 and 15 was 1.2% by mass.
＜コーティング組成物１６～１７＞
粒子成分として、ＴｉＯ２粒子、ＳｎＯ２粒子、およびＺｒＯ２粒子を表１に示す割合で混合した。
ＴｉＯ２粒子として、アナターゼ型チタニア水分散体Ｂを用いた。分散体ＢのＴｉＯ２粒子の平均二次粒子径は４０ｎｍであった。
使用したＳｎＯ２粒子、ＺｒＯ２粒子成分の分散体はコーティング組成物１～７と同じとした。これら粒子成分に、溶媒として水を添加し混合してコーティング組成物１６～１７を調製した。
コーティング組成物１６～１７の固形分濃度はいずれも１．２質量％とした。
<Coating Compositions 16-17>
As particle components, TiO 2 particles, SnO 2 particles, and ZrO 2 particles were mixed in the proportions shown in Table 1.
Anatase-type titania aqueous dispersion B was used as TiO 2 particles. The average secondary particle size of the TiO2 particles of Dispersion B was 40 nm.
The SnO 2 particle, ZrO 2 particle component dispersions used were the same as in coating compositions 1-7. Coating compositions 16 and 17 were prepared by adding water as a solvent to these particle components and mixing them.
The solid content concentration of each of Coating Compositions 16 and 17 was 1.2% by mass.
＜コーティング組成物１８～２５＞
コーティング組成物１８～２５は、特開２０１７－０８１８０７号公報（特許文献２）に記載されたコーティング組成物ａ１２～ａ１９と同一である。コーティング組成物１８～２５を以下のとおり調製した。
粒子成分として、ＴｉＯ２粒子、ＳｎＯ２粒子、およびＺｒＯ２粒子を表１に示す割合で混合した。ＴｉＯ２粒子として、アナターゼ型チタニア水分散体Ｂを用いた。使用したＳｎＯ２粒子、ＺｒＯ２粒子成分の分散体はコーティング組成物１～７と同じである。これら粒子成分に、０．３質量％の界面活性剤、および溶媒として水を添加し混合してコーティング組成物１８～２５を調製した。コーティング組成物１８～２５の固形分濃度はいずれも５．５質量％とした。
<Coating Compositions 18 to 25>
Coating compositions 18 to 25 are the same as coating compositions a12 to a19 described in JP-A-2017-081807 (Patent Document 2). Coating compositions 18-25 were prepared as follows.
As particle components, TiO 2 particles, SnO 2 particles, and ZrO 2 particles were mixed in the proportions shown in Table 1. Anatase-type titania aqueous dispersion B was used as TiO 2 particles. The SnO 2 particle, ZrO 2 particle component dispersions used are the same as for coating compositions 1-7. 0.3% by mass of a surfactant and water as a solvent were added to these particle components and mixed to prepare Coating Compositions 18 to 25. The solid content concentration of each of Coating Compositions 18 to 25 was 5.5% by mass.
光触媒塗装体の作製
＜光触媒塗装体１～１７＞
光触媒塗装体は、ＮＯｘ除去性能評価用のもの、透明性評価用のものの２種類を作製した。ＮＯｘ除去性能評価用光触媒塗装体の作製には下記基材１を用い、透明性評価用光触媒塗装体の作製には下記基材２を用いた。
・基材１：４５ｍｍ×９５ｍｍ×５ｍｍのタイルであって、表面が平滑なもの
・基材２：１００ｍｍ×１００ｍｍ×２ｍｍのガラス板
コーティング組成物１～１７を、スプレーガンを用いて、１２０℃に温めた（予熱処理した）基材に塗布した。塗布量は２８．８６ｇ／ｍ２とした。その後、コーティング組成物が塗布された基材を８００℃の雰囲気で１０秒間焼成して、基材の表面に光触媒層が形成された光触媒塗装体１～１７を得た。
Preparation of photocatalyst-coated bodies <Photocatalyst-coated bodies 1 to 17>
Two types of photocatalyst-coated bodies were produced, one for evaluation of NOx removal performance and one for evaluation of transparency. The following base material 1 was used to prepare the photocatalyst-coated body for NO x removal performance evaluation, and the following base material 2 was used to prepare the photocatalyst-coated body for transparency evaluation.
・ Substrate 1: 45 mm × 95 mm × 5 mm tile with a smooth surface ・ Substrate 2: 100 mm × 100 mm × 2 mm glass plate Coating compositions 1 to 17 are applied at 120 ° C. using a spray gun. was applied to a substrate warmed (preheated) to The coating amount was 28.86 g/m 2 . Thereafter, the base material coated with the coating composition was baked in an atmosphere of 800° C. for 10 seconds to obtain photocatalyst-coated bodies 1 to 17 having a photocatalyst layer formed on the surface of the base material.
＜光触媒塗装体１８～２１＞
光触媒塗装体１８～２１は以下のとおり作製した。
基材２を１２０℃に温め、その表面にコーティング組成物１８～２１を、スプレーガンを用いて塗布した。塗布量は１５ｇ／ｍ2とした。その後、コーティング組成物が塗布された基材を８００℃の雰囲気で１０秒間焼成して、基材の表面に光触媒層が形成された光触媒塗装体１８～２１を得た。
<Photocatalyst-coated bodies 18 to 21>
Photocatalyst-coated bodies 18 to 21 were produced as follows.
Substrate 2 was warmed to 120° C. and Coating Compositions 18 to 21 were applied to its surface using a spray gun. The coating amount was 15 g/m 2 . After that, the base material coated with the coating composition was baked in an atmosphere of 800° C. for 10 seconds to obtain photocatalyst-coated bodies 18 to 21 having a photocatalyst layer formed on the surface of the base material.
評価
＜光触媒層の膜厚の測定＞
基材１を用いて作製した光触媒塗装体１をタイルカッターにて切断し、光触媒塗装体１の断面が露出するように５×５×５ｍｍの試験片を複数準備した。その後、ＳＥＭ（ＨＩＴＡＣＨＩ製 ＳＥ８２２０）にて、３×３μｍの視野にて複数の試験片の光触媒層の厚みを測定した。観察視野は無作為に選出し、７５点の測定平均値を光触媒塗装体１の光触媒層の膜厚とした。膜厚は、１１７ｎｍであった。
Evaluation <Measurement of film thickness of photocatalyst layer>
A photocatalyst-coated body 1 produced using the base material 1 was cut with a tile cutter, and a plurality of test pieces of 5×5×5 mm were prepared so that the cross section of the photocatalyst-coated body 1 was exposed. After that, the thickness of the photocatalyst layer of a plurality of test pieces was measured with a SEM (SE8220 manufactured by HITACHI) in a field of view of 3×3 μm. The field of view for observation was selected at random, and the average value of 75 measurements was taken as the film thickness of the photocatalyst layer of the photocatalyst-coated body 1 . The film thickness was 117 nm.
光触媒塗装体２～１７については、光触媒塗装体１の光触媒層の実測膜厚（１１７ｎｍ）をベースに、各コーティング組成物の固形分濃度および塗布量の組み合わせと、各光触媒塗装体の光触媒層の膜厚との間に相関性があると考え、下記式にて、想定膜厚を理論計算した。
光触媒塗装体２～１７の光触媒層の想定膜厚＝（光触媒塗装体１の光触媒層の実測膜厚［１１７ｎｍ］）×（コーティング組成物２～１７の固形分濃度／コーティング組成物１の固形分濃度）×（コーティング組成物２～１７の塗布量／コーティング組成物１の塗布量）
例えば、光触媒塗装体４の光触媒層の想定膜厚は、１１７（ｎｍ）×（１．２［％］／０．８［％］）×（１．８［ｇ／Ａ４］／１．８［ｇ／Ａ４］）≒１７６ｎｍと算出される。
For the photocatalyst-coated bodies 2 to 17, based on the measured film thickness (117 nm) of the photocatalyst layer of the photocatalyst-coated body 1, the combination of the solid content concentration and coating amount of each coating composition, and the photocatalyst layer of each photocatalyst-coated body. Considering that there is a correlation between the thickness and the film thickness, the assumed film thickness was theoretically calculated using the following formula.
Assumed film thickness of the photocatalyst layer of the photocatalyst-coated bodies 2 to 17 = (measured film thickness of the photocatalyst layer of the photocatalyst-coated body 1 [117 nm]) × (solid content concentration of the coating compositions 2 to 17 / solid content of the coating composition 1 concentration) × (application amount of coating compositions 2 to 17 / application amount of coating composition 1)
For example, the assumed film thickness of the photocatalyst layer of the photocatalyst-coated body 4 is 117 (nm) × (1.2 [%] / 0.8 [%]) × (1.8 [g / A4] / 1.8 [ g/A4])≈176 nm.
なお、特許文献２に記載された光触媒塗装体Ａ－１２～Ａ－１９（光触媒塗装体１８～２５）の光触媒層の想定膜厚についても同様に理論計算でき、１１７（ｎｍ）×（５．５［％］／０．８［％］）×（１５．００［ｇ／ｍ２］／２８．８６［ｇ／ｍ２］）≒４１８ｎｍと算出される。 In addition, the assumed film thickness of the photocatalyst layer of the photocatalyst-coated bodies A-12 to A-19 (photocatalyst-coated bodies 18 to 25) described in Patent Document 2 can be similarly theoretically calculated, 117 (nm) × (5. 5 [%]/0.8 [%])×(15.00 [g/m 2 ]/28.86 [g/m 2 ])≈418 nm.
＜ＮＯｘ除去性能＞
基材１を用いて作製した光触媒塗装体１～１７について、ＮＯｘ除去性能を評価した。まず、これらの塗装体に前処理として１ｍＷ／ｃｍ２のＢＬＢ光を５ｈｒ以上照射した。次いで、前処理した塗装体を蒸留水に２時間浸漬し、１１０℃にて３０分以上乾燥させた。そして、ＪＩＳ Ｒ１７０１－１に記載の方法により試験を行い、ＮＯが酸化されＮＯ２が生成する反応で除去したＮＯガス量［ΔＮＯ（μｍｏｌ）］、生成したＮＯ２ガスの塗装体からの脱着量［ΔＮＯ２（μｍｏｌ）］、さらに、ΔＮＯとΔＮＯ２の差からトータルのＮＯｘ除去性能［ΔＮＯｘ（μｍｏｌ）］を求めた。結果は表１に示されるとおりであった。トータルのＮＯｘ除去性能［ΔＮＯｘ（μｍｏｌ）］の値が、０．５以上である場合、ＮＯｘ除去性能は良好であり、また０．７以上である場合、ＮＯｘ除去性能はより良好であると判断した。
なお、ローラーの代わりにスプレーガンを用いた以外は特許文献２に記載の光触媒塗装体Ａ－１４の作製方法と同様の方法で光触媒塗装体を作製し、そのＮＯｘ除去性能を測定した結果、当該塗装体と塗装体Ａ－１４のΔＮＯｘ値はほぼ同じであった。このことから、参考例Ａ１２～１４のΔＮＯｘ値として特許文献２に記載のΔＮＯｘ値を表１に引用して記載した。
< NOx removal performance>
Photocatalyst-coated bodies 1 to 17 produced using base material 1 were evaluated for NO x removal performance. First, these coated bodies were irradiated with BLB light of 1 mW/cm 2 for 5 hours or longer as a pretreatment. Then, the pretreated coated body was immersed in distilled water for 2 hours and dried at 110° C. for 30 minutes or longer. Then, a test was performed by the method described in JIS R1701-1, and the amount of NO gas [ΔNO (μmol)] removed by the reaction in which NO was oxidized to generate NO 2 , and the amount of desorption of the generated NO 2 gas from the coated body. [ΔNO 2 (μmol)], and the total NO x removal performance [ΔNO x (μmol)] was determined from the difference between ΔNO and ΔNO 2 . The results were as shown in Table 1. When the value of total NOx removal performance [ΔNOx (μmol)] is 0.5 or more, the NOx removal performance is good, and when it is 0.7 or more, the NOx removal performance is judged to be better. bottom.
A photocatalyst-coated body was prepared in the same manner as the photocatalyst-coated body A-14 described in Patent Document 2 except that a spray gun was used instead of the roller, and the NO x removal performance thereof was measured. The ΔNOx values of the coated body and the coated body A-14 were almost the same. For this reason, the ΔNOx values described in Patent Document 2 are cited in Table 1 as the ΔNOx values of Reference Examples A12 to A14.
＜透明性＞
基材２を用いて作製した光触媒塗装体１～１７および１８～２１について、透明性を評価した。具体的には、ヘイズ計（BYK Gardner製 haze-gard plus）を用いて、光触媒層のヘイズ（％）を測定した。結果を表１に示す。光触媒層のヘイズ値が１０％以下である場合、光触媒層は白く濁っておらず、透明性は高く、一方、ヘイズ値が１０％より大きい場合、光触媒層が白く濁っており、透明性が低いことが目視で確認された。
<Transparency>
Photocatalyst-coated bodies 1 to 17 and 18 to 21 produced using the base material 2 were evaluated for transparency. Specifically, the haze (%) of the photocatalyst layer was measured using a haze meter (BYK Gardner haze-gard plus). Table 1 shows the results. When the haze value of the photocatalyst layer is 10% or less, the photocatalyst layer is white and not cloudy and has high transparency, while when the haze value is greater than 10%, the photocatalyst layer is white and cloudy and has low transparency. This was confirmed visually.
Claims (12)
前記光触媒層が、光触媒粒子と、４価の正方晶からなる酸化スズ粒子と、ジルコニア粒子とを少なくとも含有し、
前記光触媒粒子の平均二次粒子径が、０ｎｍを超え２０ｎｍ未満であり、
前記光触媒粒子の含有量が、前記光触媒粒子と、前記酸化スズ粒子と、前記ジルコニア粒子との合計に対して、３５質量％以上５０質量％以下であり、
前記光触媒粒子の含有量に対する前記酸化スズ粒子の含有量の比（酸化スズ粒子／光触媒粒子）が、０．０５以上０．５以下であり、
前記光触媒層の平均膜厚が、６０ｎｍ以上２６０ｎｍ以下であり、
ＪＩＳ Ｒ１７０１－１に記載の方法により得られる、ＮＯが酸化されＮＯ ２ が生成する反応で除去したＮＯガス量［ΔＮＯ（μｍｏｌ）］と、生成したＮＯ ２ ガスの光触媒塗装体からの脱着量［ΔＮＯ ２ （μｍｏｌ）］の差［ΔＮＯ ｘ （μｍｏｌ）］が、０．５μｍｏｌ以上である
ことを特徴とする、光触媒塗装体。 A photocatalyst-coated body comprising at least a substrate and a photocatalyst layer provided on the surface of the substrate,
The photocatalyst layer contains at least photocatalyst particles, tetravalent tetragonal tin oxide particles, and zirconia particles,
The average secondary particle size of the photocatalyst particles is more than 0 nm and less than 20 nm,
The content of the photocatalyst particles is 35% by mass or more and 50% by mass or less with respect to the total of the photocatalyst particles, the tin oxide particles, and the zirconia particles,
The ratio of the content of the tin oxide particles to the content of the photocatalyst particles (tin oxide particles/photocatalyst particles) is 0.05 or more and 0.5 or less,
The average film thickness of the photocatalyst layer is 60 nm or more and 260 nm or less,
The amount of NO gas [ΔNO (μmol)] removed by the reaction in which NO is oxidized to produce NO 2 obtained by the method described in JIS R1701-1, and the amount of desorption of the produced NO 2 gas from the photocatalyst-coated body [ A photocatalyst-coated body , wherein a difference [ΔNO x (μmol)] between ΔNO 2 (μmol) ] is 0.5 μmol or more .
当該コーティング組成物が、光触媒粒子と、４価の正方晶からなる酸化スズ粒子と、ジルコニア粒子と、溶媒とを含有し、前記コーティング組成物に含有される前記光触媒粒子、前記酸化スズ粒子、および前記ジルコニア粒子の合計濃度が、０．５質量％以上１．７質量％以下である、コーティング組成物。 A coating composition for forming a photocatalyst layer provided in the photocatalyst-coated body according to any one of claims 1 to 6 ,
The coating composition contains photocatalyst particles, tetravalent tetravalent tin oxide particles, zirconia particles, and a solvent, and the photocatalyst particles, the tin oxide particles, and The coating composition, wherein the total concentration of the zirconia particles is 0.5% by mass or more and 1.7% by mass or less.
基材の表面に、光触媒粒子と、４価の正方晶からなる酸化スズ粒子と、ジルコニア粒子と、溶媒とを含有するコーティング組成物を塗布して光触媒層を形成する工程を少なくとも含み、
前記コーティング組成物に含有される前記光触媒粒子、前記酸化スズ粒子、および前記ジルコニア粒子の合計濃度が、０．５質量％以上１．７質量％以下であることを特徴とする、方法。 A method for producing a photocatalyst-coated body according to any one of claims 1 to 6 ,
At least a step of applying a coating composition containing photocatalyst particles, tetravalent tetravalent tin oxide particles, zirconia particles, and a solvent to the surface of a substrate to form a photocatalyst layer,
The method, wherein the total concentration of the photocatalyst particles, the tin oxide particles, and the zirconia particles contained in the coating composition is 0.5% by mass or more and 1.7% by mass or less.
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| WO2012014893A1 (en) | 2010-07-29 | 2012-02-02 | Toto株式会社 | Inorganic material comprising photocatalyst layer, method for producing same, and photocatalyst coating liquid for inorganic material |
| JP2017080727A (en) | 2015-10-30 | 2017-05-18 | Toto株式会社 | Photocatalyst-coated body |
| JP2017081807A (en) | 2015-10-30 | 2017-05-18 | Toto株式会社 | Photocatalyst-coated body |
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| WO2012014893A1 (en) | 2010-07-29 | 2012-02-02 | Toto株式会社 | Inorganic material comprising photocatalyst layer, method for producing same, and photocatalyst coating liquid for inorganic material |
| JP2017080727A (en) | 2015-10-30 | 2017-05-18 | Toto株式会社 | Photocatalyst-coated body |
| JP2017081807A (en) | 2015-10-30 | 2017-05-18 | Toto株式会社 | Photocatalyst-coated body |
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