JP6118154B2 - Photocatalyst - Google Patents
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- JP6118154B2 JP6118154B2 JP2013065138A JP2013065138A JP6118154B2 JP 6118154 B2 JP6118154 B2 JP 6118154B2 JP 2013065138 A JP2013065138 A JP 2013065138A JP 2013065138 A JP2013065138 A JP 2013065138A JP 6118154 B2 JP6118154 B2 JP 6118154B2
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- 239000011941 photocatalyst Substances 0.000 title claims description 361
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 156
- 239000000377 silicon dioxide Substances 0.000 claims description 75
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 66
- 238000002834 transmittance Methods 0.000 claims description 55
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- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 20
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 18
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- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 9
- 239000002904 solvent Substances 0.000 description 9
- 238000000354 decomposition reaction Methods 0.000 description 8
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 7
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- 239000011230 binding agent Substances 0.000 description 6
- 230000001699 photocatalysis Effects 0.000 description 6
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- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 5
- -1 titanium alkoxide Chemical class 0.000 description 5
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- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
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- TXKMVPPZCYKFAC-UHFFFAOYSA-N disulfur monoxide Inorganic materials O=S=S TXKMVPPZCYKFAC-UHFFFAOYSA-N 0.000 description 3
- 230000001678 irradiating effect Effects 0.000 description 3
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical compound S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 3
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
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- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
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- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910003089 Ti–OH Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
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- JJWLVOIRVHMVIS-UHFFFAOYSA-N isopropylamine Chemical compound CC(C)N JJWLVOIRVHMVIS-UHFFFAOYSA-N 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
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- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
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- UQMOLLPKNHFRAC-UHFFFAOYSA-N tetrabutyl silicate Chemical compound CCCCO[Si](OCCCC)(OCCCC)OCCCC UQMOLLPKNHFRAC-UHFFFAOYSA-N 0.000 description 1
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 1
- ZQZCOBSUOFHDEE-UHFFFAOYSA-N tetrapropyl silicate Chemical compound CCCO[Si](OCCC)(OCCC)OCCC ZQZCOBSUOFHDEE-UHFFFAOYSA-N 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Description
本発明は、所定波長の光が照射されることによって光励起される光触媒を含む光触媒層が形成された光触媒体に関する。 The present invention relates to a photocatalyst body in which a photocatalyst layer including a photocatalyst that is photoexcited when irradiated with light having a predetermined wavelength is formed.
チタニア（酸化チタン）などの光触媒は、所定波長の光が照射されることで光励起され、これによって、窒素酸化物（ＮＯｘ）、硫黄酸化物（ＳＯｘ）、および揮発性有機化合物（Volatile Organic Compounds、略称ＶＯＣ）などの有害物質を分解する分解機能、および、基材の表面を高度に親水化する超親水化機能を有することが知られている（特許文献１，２参照）。 A photocatalyst such as titania (titanium oxide) is photoexcited when irradiated with light of a predetermined wavelength, and thereby, nitrogen oxide (NOx), sulfur oxide (SOx), and volatile organic compounds (Volatile Organic Compounds), It is known to have a decomposition function for decomposing harmful substances such as abbreviation VOC) and a superhydrophilic function for highly hydrophilizing the surface of a substrate (see Patent Documents 1 and 2).
このような光触媒は、建築物、乗物および物品などを構成する部材などに、分解機能および超親水化機能を付与する物質として、基材の表面に層状に形成して設けられる。 Such a photocatalyst is formed and formed in a layered manner on the surface of a substrate as a substance that imparts a decomposition function and a superhydrophilization function to a member constituting a building, a vehicle, an article, or the like.
基材の表面に光触媒を含む光触媒層が形成された光触媒体を、たとえば、建築物の外装材などの屋外用の部材として用いた場合、太陽光が光触媒体に照射されることで光触媒が光励起され、ＮＯｘ、ＳＯｘなどの有害物質を分解する分解機能が発揮されるとともに、超親水化機能が発揮されて、光触媒体の表面に付着した汚れが降雨により洗い流される、自己浄化（セルフクリーニング）機能が発揮される。 When a photocatalyst body in which a photocatalyst layer containing a photocatalyst is formed on the surface of a substrate is used as an outdoor member such as a building exterior material, the photocatalyst is photoexcited by irradiating the photocatalyst with sunlight. Self-purification (self-cleaning) function that exhibits a decomposing function for decomposing toxic substances such as NOx and SOx, and a super-hydrophilic function, so that dirt attached to the surface of the photocatalyst is washed away by rain Is demonstrated.
また、光触媒体を、建築物の屋内に設けられるガラス部材などの屋内用の部材として用いた場合、蛍光灯などの人工光源による光が光触媒体に照射されることで光触媒が光励起され、ＶＯＣなどの有害物質を分解する分解機能が発揮されるとともに、超親水化機能が発揮されて、空気中の湿分や湯気が結露した水滴が光触媒体の表面に付着しても、その水滴を速やかに一様な水膜とし、離散した目障りな水滴が形成されることを防止する機能が発揮される。 In addition, when the photocatalyst is used as an indoor member such as a glass member provided indoors in a building, the photocatalyst is photoexcited by irradiating the photocatalyst with light from an artificial light source such as a fluorescent lamp, and VOC or the like. The function of decomposing toxic substances is demonstrated, and the function of superhydrophilicity is also demonstrated. Even if water droplets dewed from moisture or steam in the air adhere to the surface of the photocatalyst, the water droplets are quickly removed. A uniform water film is provided, and the function of preventing the formation of discrete and annoying water droplets is exhibited.
しかしながら、従来技術の光触媒体は、所定波長の光が照射されてから、超親水化機能が発現するまでに、長時間を要するという課題がある。 However, the photocatalyst of the prior art has a problem that it takes a long time after the light having a predetermined wavelength is irradiated until the superhydrophilic function is developed.
本発明の目的は、所定波長の光が照射されることによって、短時間のうちに超親水化機能が発現される光触媒体を提供することである。 An object of the present invention is to provide a photocatalyst that exhibits a superhydrophilic function in a short time when irradiated with light of a predetermined wavelength.
本発明者は、基材の表面に光触媒層が形成された光触媒体において、超親水化機能の発現能力が、光触媒層に含まれる光触媒の透過率と相関することを見出した。そして、本発明者は、アナターゼ型の結晶構造を有するチタニアに非晶質のシリカが担持された複合型の光触媒が、超親水化機能の発現能力が高い透過率を有する光触媒となることを見出し、本発明を完成させるに至った。 The present inventor has found that, in a photocatalyst having a photocatalyst layer formed on the surface of a substrate, the ability to develop a superhydrophilic function correlates with the transmittance of the photocatalyst contained in the photocatalyst layer. The present inventor has found that a composite photocatalyst in which amorphous silica is supported on titania having an anatase type crystal structure is a photocatalyst having a high transmittance and a high ability to develop a superhydrophilic function. The present invention has been completed.
本発明は、基材と、
前記基材の表面に形成される光触媒層であって、紫外線が照射されることによって光励起される、波長３５１ｎｍの光の透過率が６８〜８９％の光触媒を含む光触媒層と、を備え、
前記光触媒は、アナターゼ型の結晶構造を有するチタニアに非晶質のシリカが担持された複合型の光触媒であって、チタニアとシリカとの全モル量に対するシリカのモル量の割合が、１．１６〜２．３２モル％であることを特徴とする光触媒体である。
The present invention comprises a substrate,
A photocatalyst layer formed on the surface of the substrate, the photocatalyst layer containing a photocatalyst having a transmittance of 68 to 89% of light having a wavelength of 351 nm, which is photoexcited by being irradiated with ultraviolet rays ,
The photocatalyst is a composite photocatalyst in which amorphous silica is supported on titania having an anatase type crystal structure, and the ratio of the molar amount of silica to the total molar amount of titania and silica is 1.16. It is -2.32 mol%, It is a photocatalyst body characterized by the above-mentioned.
また本発明の光触媒体において、前記光触媒を構成するチタニアおよびシリカは、不定形状の粒子であることを特徴とする。 In the photocatalyst of the present invention, titania and silica constituting the photocatalyst are particles having an indefinite shape.
また本発明の光触媒体において、前記光触媒層は、水の接触角が１０°になるまでの所要光照射時間に基づいて算出される、ブラックライトブルー蛍光ランプを用いて２ｍＷ／ｃｍ ２ の照度で光が照射された直後からの、水の接触角の低下速度が、１．０８〜１．６０（°／Ｈｒ）であることを特徴とする。
In the photocatalyst body of the present invention, the photocatalyst layer has an illuminance of 2 mW / cm 2 using a black light blue fluorescent lamp , which is calculated based on a required light irradiation time until the contact angle of water reaches 10 °. from immediately after the light is applied, the rate of decrease in the contact angle of water, characterized in that it is a 1.08~1.60 (° / Hr).
本発明によれば、光触媒体は、基材と、該基材の表面に形成される光触媒層とを含んで構成される。光触媒層は、透過率が６８〜８９％の光触媒を含んでおり、この光触媒は、アナターゼ型の結晶構造を有するチタニアに非晶質のシリカが担持された複合型の光触媒である。チタニアにシリカが担持された複合型の光触媒においてシリカは、透過率を前記範囲に調整する機能を有している。 According to this invention, a photocatalyst body is comprised including a base material and the photocatalyst layer formed in the surface of this base material. The photocatalyst layer contains a photocatalyst having a transmittance of 68 to 89%, and this photocatalyst is a composite photocatalyst in which amorphous silica is supported on titania having an anatase type crystal structure. In the composite photocatalyst in which silica is supported on titania, silica has a function of adjusting the transmittance within the above range.
従来技術の光触媒体（基材の表面に光触媒を含む光触媒層が形成されたもの）は、たとえば、テトラエトキシシランとアナターゼ型チタニアゾルとが溶媒中に混合されたコーティング溶液を基材の表面に塗布した後、１５０℃程度の温度に保持することにより、テトラエトキシシランを加水分解と脱水縮重合に付し、アナターゼ型チタニア粒子がシリカのバインダーで結着された光触媒層を基材の表面に形成して製造される。このような従来技術の光触媒体は、光触媒機能を有するアナターゼ型チタニア粒子がシリカのバインダーで結着された光触媒層が、基材の表面に形成されたものである。このような光触媒体は、所定波長の光が照射されてから、超親水化機能が発現されるまでに、６０時間程度の長時間を要する。この理由は、シリカのバインダー成分に紫外線（光）透過が阻害され、均一に光がチタニア粒子表面に到達しないためであるからだと考えられる。 A conventional photocatalyst (with a photocatalyst layer containing a photocatalyst formed on the surface of a base material), for example, is applied to the surface of the base material with a coating solution in which tetraethoxysilane and anatase-type titania sol are mixed in a solvent. Then, by maintaining the temperature at about 150 ° C., the tetraethoxysilane is subjected to hydrolysis and dehydration condensation polymerization, and a photocatalytic layer in which anatase-type titania particles are bound with a silica binder is formed on the surface of the substrate. Manufactured. In such a conventional photocatalyst, a photocatalyst layer in which anatase-type titania particles having a photocatalytic function are bound with a silica binder is formed on the surface of a substrate. Such a photocatalyst requires a long time of about 60 hours after the light having a predetermined wavelength is irradiated until the superhydrophilic function is exhibited. The reason for this is considered to be that the ultraviolet light (light) transmission is inhibited by the binder component of silica and the light does not uniformly reach the surface of the titania particles.
これに対して、本発明の光触媒体では、光触媒を構成するシリカは、バインダーとして機能するものではなく、透過率を６８〜８９％の範囲に調整する機能を有し、紫外線（光）透過を阻害することが防止される。その結果、紫外線（光）透過率に優れた高い光触媒活性を持つ光触媒体となる。したがって、本発明の光触媒体は、所定波長の光が照射されることによって、短時間のうちに超親水化機能が発現される。 In contrast, in the photocatalyst of the present invention, the silica constituting the photocatalyst does not function as a binder, but has a function of adjusting the transmittance to a range of 68 to 89%, and transmits ultraviolet light. Inhibiting is prevented. As a result, a photocatalyst having a high photocatalytic activity excellent in ultraviolet (light) transmittance is obtained. Therefore, the photocatalyst of the present invention exhibits a superhydrophilic function in a short time when irradiated with light of a predetermined wavelength.
また本発明によれば、光触媒を構成するチタニアおよびシリカは、不定形状の粒子である。不定形状の粒子は、球形粒子に比べて凝集粒子の形成度合いが低いので、１つの大きな凝集粒子として振舞うことが抑制され、光の散乱を抑制することができる。したがって、光触媒を構成するチタニアおよびシリカが不定形状の粒子であることによって、光触媒層の光散乱による白濁を防止することができ、光触媒層を実質的に透明とすることができる。これによって、光触媒層に対する光の入射光量を大きくすることができるので、光触媒体に光が照射されてから超親水化機能が発現されるまでの時間を短縮することができる。 Further, according to the present invention, titania and silica constituting the photocatalyst are irregularly shaped particles. Since the irregularly shaped particles have a lower degree of formation of aggregated particles than spherical particles, they can be suppressed from acting as one large aggregated particle, and light scattering can be suppressed. Therefore, since the titania and silica constituting the photocatalyst are particles having an irregular shape, white turbidity due to light scattering of the photocatalyst layer can be prevented, and the photocatalyst layer can be made substantially transparent. Accordingly, the amount of light incident on the photocatalyst layer can be increased, so that the time from when the photocatalyst body is irradiated with light until the superhydrophilic function is manifested can be shortened.
また、不定形状の粒子は、球形粒子に比べて比表面積が大きいので、光触媒の基材表面に対する密着摩耗性を向上させることができる。したがって、光触媒を構成するチタニアおよびシリカが不定形状の粒子であることによって、光触媒層が基材表面から剥離することが抑制され、優れた密着摩耗性を有する強固な光触媒層とすることができる。 In addition, since the irregularly shaped particles have a larger specific surface area than the spherical particles, it is possible to improve the adhesion wear property of the photocatalyst to the substrate surface. Therefore, when titania and silica constituting the photocatalyst are particles having an indefinite shape, the photocatalyst layer is prevented from being peeled off from the surface of the substrate, and a strong photocatalyst layer having excellent adhesion wear properties can be obtained.
また本発明によれば、光触媒は、チタニアとシリカとの全モル量に対するシリカのモル量の割合が、１．１６〜２．３２モル％である。これによって、光触媒の基材表面に対する優れた密着摩耗性を維持した上で、光触媒の透過率を６８〜８９％の範囲に調整することができ、光触媒体に光が照射されてから超親水化機能が発現されるまでの時間短縮化の効果を維持することができる。 Moreover, according to this invention, the ratio of the molar amount of a silica with respect to the total molar amount of a titania and a silica is 1.16-2.32 mol%. This makes it possible to adjust the photocatalyst transmittance to a range of 68 to 89% while maintaining excellent adhesion and abrasion to the substrate surface of the photocatalyst, and to make the photocatalyst body super-hydrophilic after being irradiated with light. The effect of shortening the time until the function is expressed can be maintained.
また本発明によれば、光触媒層は、水の接触角が１０°になるまでの所要光照射時間に基づいて算出される、光照射された直後からの、水の接触角の低下速度が、１．０８〜１．６０（°／Ｈｒ）であり、光触媒体に光が照射されてから超親水化機能が発現されるまでの時間が短いものとなる。 Further, according to the present invention, the photocatalyst layer is calculated based on the required light irradiation time until the water contact angle reaches 10 °. It is 1.08 to 1.60 (° / Hr), and the time from when the photocatalyst is irradiated with light until the superhydrophilic function is manifested is short.
図１は、本発明の一実施形態に係る光触媒体１の構成を模式的に示す図である。本実施形態の光触媒体１は、基材２と、基材２の表面を被覆するように形成される光触媒層３とを含んで構成され、建築物、乗物および物品などを構成する部材として用いられ、光触媒機能を有するものである。 FIG. 1 is a diagram schematically showing a configuration of a photocatalyst body 1 according to an embodiment of the present invention. The photocatalyst body 1 of the present embodiment is configured to include a base material 2 and a photocatalyst layer 3 formed so as to cover the surface of the base material 2, and is used as a member constituting a building, a vehicle, an article, and the like. And has a photocatalytic function.
基材２の材質としては、たとえば、金属、セラミックス、ガラス、プラスチックス、木、石、セメント、コンクリートなどが挙げられる。具体的には、基材２としては、釉薬層が形成された施釉タイル、窓枠、窓ガラス、浴室用または洗面所用の鏡などの建築物の屋外用・屋内用の部材、自動車、鉄道車両、航空機、船舶、潜水艇などの乗物の窓ガラスなどの部材、眼鏡レンズ、光学レンズ、内視鏡レンズ、照明用レンズ、歯科用歯鏡、道路鏡などの物品の部材などを挙げることができる。 Examples of the material of the substrate 2 include metals, ceramics, glass, plastics, wood, stones, cement, and concrete. Specifically, as the base material 2, outdoor or indoor parts of buildings such as glazed tiles, window frames, window glass, bathroom or toilet mirrors on which glaze layers are formed, automobiles, railway vehicles , Members such as aircraft, ships, submersibles and other vehicle windows, eyeglass lenses, optical lenses, endoscope lenses, illumination lenses, dental teeth mirrors, road mirrors, etc. .
基材２の表面に形成される光触媒層３は、光触媒３１を含んで構成される。光触媒３１は、アナターゼ型の結晶構造を有するチタニア３１１に非晶質のシリカ３１２が担持された複合型（以下、「チタニア−シリカ複合型」という）の光触媒である。 The photocatalyst layer 3 formed on the surface of the substrate 2 includes a photocatalyst 31. The photocatalyst 31 is a composite type photocatalyst in which amorphous silica 312 is supported on titania 311 having an anatase type crystal structure (hereinafter referred to as “titania-silica composite type”).
チタニア−シリカ複合型の光触媒３１において、チタニア３１１は、所定波長の光（紫外線）が照射されることによって光励起される。チタニア３１１は、所定波長の光によって光励起されると、水が水酸基の形で表面に化学吸着され、その結果、光触媒体１の超親水化機能が発現されるものと考えられる。ここで、「超親水」の用語は、水との接触角に換算して１０°以下、好ましくは５°以下の親水性（水濡れ性）を意味する。また、チタニア−シリカ複合型の光触媒３１において、シリカ３１２は、光触媒体１の超親水化機能を補助する役割を担うとともに、光触媒３１の透過率を調整する機能を有する。 In the titania-silica composite type photocatalyst 31, the titania 311 is photoexcited when irradiated with light (ultraviolet rays) having a predetermined wavelength. When the titania 311 is photoexcited by light of a predetermined wavelength, water is chemisorbed on the surface in the form of hydroxyl groups, and as a result, the superhydrophilic function of the photocatalyst 1 is expressed. Here, the term “superhydrophilic” means hydrophilicity (water wettability) of 10 ° or less, preferably 5 ° or less in terms of a contact angle with water. Further, in the titania-silica composite type photocatalyst 31, the silica 312 has a function of assisting the superhydrophilic function of the photocatalyst body 1 and a function of adjusting the transmittance of the photocatalyst 31.
本実施形態の光触媒体１において、光触媒層３を構成する光触媒３１は、透過率が６８〜８９％である。 In the photocatalyst body 1 of this embodiment, the photocatalyst 31 constituting the photocatalyst layer 3 has a transmittance of 68 to 89%.
ここで、光触媒３１の透過率は、光が光触媒３１に照射されたときの光透過率を表し、透過率が高いほど、高い光透過性を示すことになる。この光触媒３１の透過率は、光触媒体１に照射される光の波長によって異なる値を示すが、本実施形態では、光触媒３１の透過率は、波長３５１ｎｍの光が照射されたときの値である。また、光触媒３１の透過率は、具体的には、ＪＩＳ Ｒ ３１０６に従って測定されたものであり、石英ガラスの表面に光触媒３１により構成される光触媒層３が形成された試料について、透過率測定装置（自己分光光度計、Ｕ−４０００、株式会社日立製作所製）にて測定されたものである。なお、光触媒層形成前の石英ガラス自身の透過率は、９３％である。 Here, the transmittance of the photocatalyst 31 represents the light transmittance when the photocatalyst 31 is irradiated with light, and the higher the transmittance, the higher the light transmittance. The transmittance of the photocatalyst 31 shows a different value depending on the wavelength of light irradiated on the photocatalyst body 1, but in this embodiment, the transmittance of the photocatalyst 31 is a value when light having a wavelength of 351 nm is irradiated. . Further, the transmittance of the photocatalyst 31 is specifically measured according to JIS R 3106, and a transmittance measuring device is used for a sample in which the photocatalyst layer 3 composed of the photocatalyst 31 is formed on the surface of quartz glass. (Self spectrophotometer, U-4000, manufactured by Hitachi, Ltd.). In addition, the transmittance | permeability of quartz glass itself before photocatalyst layer formation is 93%.
光触媒３１の透過率の前記範囲は、以下に示す実験の結果に基づいて設定されたものである。 The said range of the transmittance | permeability of the photocatalyst 31 is set based on the result of the experiment shown below.
［透過率の異なる光触媒を含む光触媒組成物の製造］
（光触媒組成物Ａ１の製造）
チタンアルコキシドとしてテトライソプロポキシチタン(チタニウムイソプロポキシド)に酢酸を重量比で約１：１を配合し、常温若しくは２０〜３０℃で約１時間撹拌混合して、不定形状の非晶質のチタニアが酢酸中に分散された非晶質チタニア分散体を作製した。次に、固形分濃度１４％の非晶質チタニア分散体と、固形分濃度１６％のシリカゾル（不定形状の非晶質のシリカが酢酸中に分散された分散液）と、溶媒（水）とを重量比で、（非晶質チタニア分散体中のチタニア）：（シリカゾル中のシリカ）：（水）＝２９：０．４：７０．６となるように混合して、非晶質のチタニアおよび非晶質のシリカの混合物が溶媒（水）中に分散された混合物分散体を得た。この場合、非晶質チタニア分散体に含まれるチタニアとシリカゾルに含まれるシリカとの全モル量に対する、シリカのモル量の割合は、２．３２モル％である。
[Production of photocatalyst compositions containing photocatalysts having different transmittances]
(Production of photocatalyst composition A1)
As titanium alkoxide, tetraisopropoxy titanium (titanium isopropoxide) is mixed with acetic acid at a weight ratio of about 1: 1, and stirred and mixed at room temperature or 20-30 ° C. for about 1 hour to form amorphous titania having an irregular shape. An amorphous titania dispersion in which is dispersed in acetic acid was prepared. Next, an amorphous titania dispersion having a solid content concentration of 14%, a silica sol having a solid content concentration of 16% (a dispersion in which amorphous silica having an irregular shape is dispersed in acetic acid), a solvent (water), Are mixed in a weight ratio of (titania in amorphous titania dispersion) :( silica in silica sol) :( water) = 29: 0.4: 70.6 to obtain amorphous titania. And a mixture dispersion in which a mixture of amorphous silica was dispersed in a solvent (water) was obtained. In this case, the ratio of the molar amount of silica to the total molar amount of titania contained in the amorphous titania dispersion and silica contained in the silica sol is 2.32 mol%.
次に、混合物分散体を７０〜８０℃の温度下で、約２〜３時間撹拌混合することで、混合物分散体中の非晶質のチタニアをアナターゼ型の結晶構造を有するチタニアに変質させて、結晶質のチタニアに非晶質のシリカが担持された複合型の光触媒（チタニア−シリカ複合型光触媒）を生成し、この生成された光触媒が溶媒（水）中に分散された光触媒組成物を得た。さらに、この光触媒組成物に、イソプロピルアミンを添加して２０〜５０℃の温度下で１〜２時間撹拌混合することでｐＨをアルカリ化して、チタニア−シリカ複合型光触媒が含まれた光触媒組成物Ａ１を得た。この光触媒組成物Ａ１に含まれる光触媒の透過率は、波長３５１ｎｍの光が照射されたときの値が６８％であった。 Next, the mixture dispersion is stirred and mixed at a temperature of 70 to 80 ° C. for about 2 to 3 hours to transform amorphous titania in the mixture dispersion into titania having anatase type crystal structure. A composite photocatalyst in which amorphous silica is supported on crystalline titania (titania-silica composite photocatalyst) is produced, and the produced photocatalyst is dispersed in a solvent (water). Obtained. Further, to this photocatalyst composition, isopropylamine was added and the mixture was stirred and mixed at a temperature of 20 to 50 ° C. for 1 to 2 hours to alkalinize the pH, and the photocatalyst composition containing a titania-silica composite photocatalyst was contained. A1 was obtained. The transmittance of the photocatalyst contained in this photocatalyst composition A1 was 68% when irradiated with light having a wavelength of 351 nm.
（光触媒組成物Ａ２の製造）
固形分濃度１４％の非晶質チタニア分散体と、固形分濃度１６％のシリカゾルと、溶媒（水）とを、重量比で、（非晶質チタニア分散体中のチタニア）：（シリカゾル中のシリカ）：（水）＝２９：０．２：７０．８となるように混合したこと以外は、上記の光触媒組成物Ａ１と同様にして、チタニア−シリカ複合型光触媒が含まれた光触媒組成物Ａ２を得た。なお、この場合、非晶質チタニア分散体に含まれるチタニアとシリカゾルに含まれるシリカとの全モル量に対する、シリカのモル量の割合は、１．１６モル％である。光触媒組成物Ａ２に含まれる光触媒の透過率は、波長３５１ｎｍの光が照射されたときの値が８９％であった。
(Production of photocatalyst composition A2)
A weight ratio of an amorphous titania dispersion having a solid content concentration of 14%, a silica sol having a solid content concentration of 16%, and a solvent (water): (titania in the amorphous titania dispersion): (in the silica sol (Silica): (Water) = 29: 0.2: 70.8 Photocatalyst composition containing a titania-silica composite photocatalyst in the same manner as the photocatalyst composition A1, except that the mixture was mixed to be 70.8. A2 was obtained. In this case, the ratio of the molar amount of silica to the total molar amount of titania contained in the amorphous titania dispersion and silica contained in the silica sol is 1.16 mol%. The transmittance of the photocatalyst contained in the photocatalyst composition A2 was 89% when irradiated with light having a wavelength of 351 nm.
（光触媒組成物Ａ３の製造）
固形分濃度１４％の非晶質チタニア分散体と、固形分濃度１６％のシリカゾルと、溶媒（水）とを、重量比で、（非晶質チタニア分散体中のチタニア）：（シリカゾル中のシリカ）：（水）＝２９：０．３：７０．７となるように混合したこと以外は、上記の光触媒組成物Ａ１と同様にして、チタニア−シリカ複合型光触媒が含まれた光触媒組成物Ａ３を得た。なお、この場合、非晶質チタニア分散体に含まれるチタニアとシリカゾルに含まれるシリカとの全モル量に対する、シリカのモル量の割合は、１．７４モル％である。光触媒組成物Ａ３に含まれる光触媒の透過率は、波長３５１ｎｍの光が照射されたときの値が、６８％と８９％との間の７８％であった。
(Production of photocatalyst composition A3)
A weight ratio of an amorphous titania dispersion having a solid content concentration of 14%, a silica sol having a solid content concentration of 16%, and a solvent (water): (titania in the amorphous titania dispersion): (in the silica sol (Silica): (Water) = 29: 0.3: Photocatalyst composition containing a titania-silica composite photocatalyst in the same manner as the photocatalyst composition A1 except that the mixture was mixed to 70.7. A3 was obtained. In this case, the ratio of the molar amount of silica to the total molar amount of titania contained in the amorphous titania dispersion and silica contained in the silica sol is 1.74 mol%. The transmittance of the photocatalyst contained in the photocatalyst composition A3 was 78% between 68% and 89% when irradiated with light having a wavelength of 351 nm.
（光触媒組成物Ａ４の製造）
固形分濃度１４％の非晶質チタニア分散体と、固形分濃度１６％のシリカゾルと、溶媒（水）とを、重量比で、（非晶質チタニア分散体中のチタニア）：（シリカゾル中のシリカ）：（水）＝２９：０．７：７０．３となるように混合したこと以外は、上記の光触媒組成物Ａ１と同様にして、チタニア−シリカ複合型光触媒が含まれた光触媒組成物Ａ４を得た。なお、この場合、非晶質チタニア分散体に含まれるチタニアとシリカゾルに含まれるシリカとの全モル量に対する、シリカのモル量の割合は、４．１モル％である。光触媒組成物Ａ４に含まれる光触媒の透過率は、波長３５１ｎｍの光が照射されたときの値が、６８％よりも小さい値の６６％であった。
(Production of photocatalyst composition A4)
A weight ratio of an amorphous titania dispersion having a solid content concentration of 14%, a silica sol having a solid content concentration of 16%, and a solvent (water): (titania in the amorphous titania dispersion): (in the silica sol (Silica): (Water) = 29: 0.7: A photocatalyst composition containing a titania-silica composite photocatalyst in the same manner as the photocatalyst composition A1 except that the mixture was mixed to be 70.3. A4 was obtained. In this case, the ratio of the molar amount of silica to the total molar amount of titania contained in the amorphous titania dispersion and silica contained in the silica sol is 4.1 mol%. The transmittance of the photocatalyst contained in the photocatalyst composition A4 was 66%, which is a value smaller than 68% when irradiated with light having a wavelength of 351 nm.
（光触媒組成物Ａ５の製造）
固形分濃度１４％の非晶質チタニア分散体と、固形分濃度１６％のシリカゾルと、溶媒（水）とを、重量比で、（非晶質チタニア分散体中のチタニア）：（シリカゾル中のシリカ）：（水）＝２９：０．１：７０．９となるように混合したこと以外は、上記の光触媒組成物Ａ１と同様にして、チタニア−シリカ複合型光触媒が含まれた光触媒組成物Ａ５を得た。なお、この場合、非晶質チタニア分散体に含まれるチタニアとシリカゾルに含まれるシリカとの全モル量に対する、シリカのモル量の割合は、０．５８モル％である。光触媒組成物Ａ５に含まれる光触媒の透過率は、波長３５１ｎｍの光が照射されたときの値が、８９％よりも大きい値の９１％であった。
(Production of photocatalyst composition A5)
A weight ratio of an amorphous titania dispersion having a solid content concentration of 14%, a silica sol having a solid content concentration of 16%, and a solvent (water): (titania in the amorphous titania dispersion): (in the silica sol Silica): (Water) = 29: 0.1: A photocatalyst composition containing a titania-silica composite photocatalyst in the same manner as the photocatalyst composition A1 except that the mixture was mixed so that the ratio was 70.9. A5 was obtained. In this case, the ratio of the molar amount of silica to the total molar amount of titania contained in the amorphous titania dispersion and silica contained in the silica sol is 0.58 mol%. The transmittance of the photocatalyst contained in the photocatalyst composition A5 was 91%, which is a value greater than 89% when irradiated with light having a wavelength of 351 nm.
（光触媒組成物Ａ６の製造）
テトラエトキシシラン（和光純薬工業株式会社製）とアナターゼ型チタニアゾル（Ｋ０３、石原産業株式会社製）を使用し、シリカのモル比が約４０％になるようにコーティング溶液を作製し、比較のための従来技術の光触媒が含まれた光触媒組成物Ａ６を得た。この光触媒組成物Ａ６に含まれる光触媒の透過率は、波長３５１ｎｍの光が照射されたときの値が、６２％であった。
(Production of photocatalyst composition A6)
Using tetraethoxysilane (manufactured by Wako Pure Chemical Industries, Ltd.) and anatase type titania sol (K03, manufactured by Ishihara Sangyo Co., Ltd.), a coating solution was prepared so that the molar ratio of silica was about 40%. The photocatalyst composition A6 containing the conventional photocatalyst was obtained. The transmittance of the photocatalyst contained in this photocatalyst composition A6 was 62% when irradiated with light having a wavelength of 351 nm.
［光触媒体の製造］
釉薬層が形成された施釉タイルを基材として用い、上記の光触媒組成物Ａ１〜Ａ６を用いて６種の光触媒体ＡＡ１〜ＡＡ６を製造した。
[Manufacture of photocatalyst]
Six types of photocatalysts AA1 to AA6 were produced using the above-mentioned photocatalyst compositions A1 to A6 using the glazed tile on which the glaze layer was formed as a base material.
（光触媒体ＡＡ１の製造）
施釉タイル基材を表面温度が１００℃になるようにプレヒートした後、超音波スプレーコート法により光触媒組成物Ａ１を塗布し、その後、５００℃で１５分間焼き付けすることによって、透過率６８％の光触媒により構成された光触媒層が形成された光触媒体ＡＡ１を得た。
(Production of photocatalyst AA1)
After preheating the glazed tile substrate so that the surface temperature becomes 100 ° C., the photocatalyst composition A1 is applied by an ultrasonic spray coating method, and then baked at 500 ° C. for 15 minutes, whereby a photocatalyst having a transmittance of 68% is obtained. The photocatalyst body AA1 in which the photocatalyst layer comprised by this was formed was obtained.
（光触媒体ＡＡ２の製造）
施釉タイル基材を表面温度が１００℃になるようにプレヒートした後、超音波スプレーコート法により光触媒組成物Ａ２を塗布し、その後、５００℃で１時間焼き付けすることによって、透過率８９％の光触媒により構成された光触媒層が形成された光触媒体ＡＡ２を得た。
(Production of photocatalyst AA2)
After preheating the glazed tile substrate so that the surface temperature becomes 100 ° C., the photocatalyst composition A2 is applied by an ultrasonic spray coating method, and then baked at 500 ° C. for 1 hour, whereby a photocatalyst having a transmittance of 89% The photocatalyst body AA2 in which the photocatalyst layer comprised by this was formed was obtained.
（光触媒体ＡＡ３の製造）
施釉タイル基材を表面温度が１００℃になるようにプレヒートした後、超音波スプレーコート法により光触媒組成物Ａ３を塗布し、その後、５００℃で１時間焼き付けすることによって、透過率が６８％と８９％との間の７８％の光触媒により構成された光触媒層が形成された光触媒体ＡＡ３を得た。
(Production of photocatalyst AA3)
After preheating the glazed tile substrate so that the surface temperature becomes 100 ° C., the photocatalyst composition A3 is applied by an ultrasonic spray coating method, and then baked at 500 ° C. for 1 hour, whereby the transmittance is 68%. A photocatalyst AA3 in which a photocatalyst layer constituted by 78% of the photocatalyst between 89% was formed was obtained.
（光触媒体ＡＡ４の製造）
施釉タイル基材を表面温度が１００℃になるようにプレヒートした後、超音波スプレーコート法により光触媒組成物Ａ４を塗布し、その後、５００℃で１時間焼き付けすることによって、透過率が６８％よりも小さい値の６６％の光触媒により構成された光触媒層が形成された光触媒体ＡＡ４を得た。
(Production of photocatalyst AA4)
After preheating the glazed tile base material so that the surface temperature becomes 100 ° C., the photocatalyst composition A4 is applied by an ultrasonic spray coating method, and then baked at 500 ° C. for 1 hour. A photocatalyst AA4 having a photocatalyst layer composed of 66% of the photocatalyst having a smaller value was obtained.
（光触媒体ＡＡ５の製造）
施釉タイル基材を表面温度が１００℃になるようにプレヒートした後、超音波スプレーコート法により光触媒組成物Ａ５を塗布し、その後、５００℃で１時間焼き付けすることによって、透過率が８９％よりも大きい値の９１％の光触媒により構成された光触媒層が形成された光触媒体ＡＡ５を得た。
(Production of photocatalyst AA5)
After preheating the glazed tile substrate so that the surface temperature becomes 100 ° C., the photocatalyst composition A5 is applied by an ultrasonic spray coating method, and then baked at 500 ° C. for 1 hour, whereby the transmittance is 89% or more. A photocatalyst AA5 in which a photocatalyst layer composed of a photocatalyst of 91% having a larger value was formed was obtained.
（光触媒体ＡＡ６の製造）
施釉タイル基材を表面温度が１００℃になるようにプレヒートした後、超音波スプレーコート法により光触媒組成物Ａ６を塗布し、その後、５００℃で１時間焼き付けすることによって、透過率が６２％の光触媒により構成された光触媒層が形成された光触媒体ＡＡ６を得た。
(Production of photocatalyst AA6)
After preheating the glazed tile substrate so that the surface temperature becomes 100 ° C., the photocatalyst composition A6 is applied by an ultrasonic spray coating method, and then baked at 500 ° C. for 1 hour, whereby the transmittance is 62%. Photocatalyst body AA6 in which the photocatalyst layer comprised with the photocatalyst was formed was obtained.
［実験結果］
上記のようにして製造した６種の光触媒体ＡＡ１〜ＡＡ６について、ＪＩＳ−Ｒ１７０１３−１「ファインセラミックス−光触媒材料のセルフクリーニング性能評価試験方法−第１部：水接触角の測定」に準じて試験を行い、光照射後の水との接触角を測定した。なお、各光触媒体ＡＡ１〜ＡＡ６の水との接触角は、接触角測定器（ＤＭ５００型、協和界面科学社製）を用いて測定した。具体的な接触角の測定手順としては、各光触媒体ＡＡ１〜ＡＡ６の光照射前の水との接触角を測定した後、光源としてブラックライトブルー蛍光ランプを用いて各光触媒体ＡＡ１〜ＡＡ６の光触媒層側の表面に、２ｍＷ／ｃｍ２の照度で光を照射し、８時間ごとに水との接触角の時間的変化を測定した。
[Experimental result]
The six types of photocatalysts AA1 to AA6 produced as described above were tested according to JIS-R17013-1, "Fine ceramics-Test method for evaluating self-cleaning performance of photocatalyst materials-Part 1: Measurement of water contact angle" The contact angle with water after light irradiation was measured. In addition, the contact angle with water of each photocatalyst body AA1-AA6 was measured using the contact angle measuring device (DM500 type | mold, Kyowa Interface Science company make). As a specific measurement procedure of the contact angle, after measuring the contact angle of each photocatalyst AA1 to AA6 with water before light irradiation, a photocatalyst of each photocatalyst AA1 to AA6 using a black light blue fluorescent lamp as a light source The surface on the layer side was irradiated with light at an illuminance of 2 mW / cm 2 , and the temporal change in the contact angle with water was measured every 8 hours.
測定結果を図２に示す。図２は、光触媒体の光照射に伴う水との接触角の時間的変化を示すグラフである。図２のグラフにおいて、横軸は光照射時間（Ｈｒ）を示し、縦軸は水との接触角（°）を示す。また、図２のグラフにおいて、「白丸」のプロットは光触媒体ＡＡ１の測定結果を示し、「黒丸」のプロットは光触媒体ＡＡ２の測定結果を示し、「白四角」のプロットは光触媒体ＡＡ３の測定結果を示し、「白三角」のプロットは光触媒体ＡＡ４の測定結果を示し、「黒三角」のプロットは光触媒体ＡＡ５の測定結果を示し、「バツ」のプロットは光触媒体ＡＡ６の測定結果を示す。 The measurement results are shown in FIG. FIG. 2 is a graph showing a temporal change in contact angle with water accompanying light irradiation of the photocatalyst. In the graph of FIG. 2, the horizontal axis indicates the light irradiation time (Hr), and the vertical axis indicates the contact angle (°) with water. In the graph of FIG. 2, the “white circle” plot indicates the measurement result of the photocatalyst AA1, the “black circle” plot indicates the measurement result of the photocatalyst AA2, and the “white square” plot indicates the measurement of the photocatalyst AA3. The result shows a measurement result of the photocatalyst AA4, a plot of “black triangle” shows a measurement result of the photocatalyst AA5, and a plot of “X” shows a measurement result of the photocatalyst AA6. .
図２のグラフから明らかなように、透過率が６８％、７８％、および８９％の光触媒を含む光触媒組成物Ａ１〜Ａ３を用いて製造された光触媒体ＡＡ１〜ＡＡ３は、透過率が６２％の光触媒を含む光触媒組成物Ａ６を用いて製造された光触媒体ＡＡ６に対して、光照射の初期段階において水との接触角が大きく低下することが分かる。 As apparent from the graph of FIG. 2, the photocatalysts AA1 to AA3 produced using the photocatalyst compositions A1 to A3 containing the photocatalysts having a transmittance of 68%, 78%, and 89% have a transmittance of 62%. It can be seen that, for the photocatalyst AA6 produced using the photocatalyst composition A6 containing this photocatalyst, the contact angle with water greatly decreases in the initial stage of light irradiation.
また、図２の実験結果に基づいて、水との接触角の低下速度について検討したのが図３である。図３は、光触媒の透過率と接触角の低下速度との関係を示すグラフである。図３のグラフにおいて、横軸は光触媒の透過率（％）を示し、縦軸は水との接触角の低下速度（°／Ｈｒ）を示す。なお、接触角の低下速度は、光照射前の水との接触角から、光触媒体の超親水化機能発現の基準となる、水との接触角が１０°になるまでの所要光照射時間に基づくものであり、（光照射前の接触角−１０）［°］／所要光照射時間［Ｈｒ］に従って算出される。 FIG. 3 shows the rate of decrease in the contact angle with water based on the experimental results of FIG. FIG. 3 is a graph showing the relationship between the transmittance of the photocatalyst and the decrease rate of the contact angle. In the graph of FIG. 3, the horizontal axis represents the transmittance (%) of the photocatalyst, and the vertical axis represents the rate of decrease in the contact angle with water (° / Hr). In addition, the rate of decrease in the contact angle is determined from the contact angle with water before light irradiation to the required light irradiation time until the contact angle with water becomes 10 °, which is a reference for the expression of the superhydrophilization function of the photocatalyst. Based on (contact angle before light irradiation−10) [°] / required light irradiation time [Hr].
図２，３の実験結果より、従来技術の光触媒を含む光触媒組成物Ａ６を用いて製造された光触媒体ＡＡ６は、光照射直後からの、水の接触角の低下速度が０．７４［°／Ｈｒ］となり、光照射直後から超親水化機能（水との接触角が１０°以下となる）が発現するまでに、６４時間程度の長時間を要することが分かる。この理由は、シリカのバインダー成分に紫外線（光）透過が阻害され、均一に光がチタニア粒子表面に到達しないためであるからだと考えられる。 From the experimental results of FIGS. 2 and 3, the photocatalyst AA6 produced using the photocatalyst composition A6 containing the photocatalyst of the prior art has a decrease rate of water contact angle of 0.74 [° / Hr], and it is understood that it takes a long time of about 64 hours from the time of light irradiation until the superhydrophilic function (the contact angle with water becomes 10 ° or less) is developed. The reason for this is considered to be that the ultraviolet light (light) transmission is inhibited by the binder component of silica and the light does not uniformly reach the surface of the titania particles.
これに対して、透過率が６８％の光触媒を含む光触媒組成物Ａ１を用いて製造された光触媒体ＡＡ１は、光照射直後からの、水の接触角の低下速度が１．０８［°／Ｈｒ］となり、光照射直後から超親水化機能が発現するまでの所要時間は、光触媒体ＡＡ６の６４時間よりも短時間の３９時間程度となる。また、透過率が８９％の光触媒を含む光触媒組成物Ａ２を用いて製造された光触媒体ＡＡ２は、光照射直後からの、水の接触角の低下速度が１．５１［°／Ｈｒ］となり、光照射直後から超親水化機能が発現するまでの所要時間は、光触媒体ＡＡ６の６４時間よりも短時間の３０時間程度となる。 In contrast, the photocatalyst AA1 produced using the photocatalyst composition A1 containing a photocatalyst having a transmittance of 68% has a rate of decrease in the contact angle of water of 1.08 [° / Hr immediately after light irradiation. Thus, the time required from the time immediately after the light irradiation to the development of the superhydrophilic function is about 39 hours, which is shorter than 64 hours of the photocatalyst AA6. In addition, the photocatalyst AA2 produced using the photocatalyst composition A2 containing a photocatalyst having a transmittance of 89% has a rate of decrease in water contact angle of 1.51 [° / Hr] immediately after light irradiation, The time required from the time immediately after the light irradiation to the development of the superhydrophilic function is about 30 hours, which is shorter than 64 hours of the photocatalyst AA6.
また、透過率が７８％の光触媒を含む光触媒組成物Ａ３を用いて製造された光触媒体ＡＡ３は、光照射直後からの、水の接触角の低下速度が１．３８［°／Ｈｒ］となり、光照射直後から超親水化機能が発現するまでの所要時間は、光触媒体ＡＡ６の６４時間よりも短時間の３２時間程度となる。また、透過率が６６％の光触媒を含む光触媒組成物Ａ４を用いて製造された光触媒体ＡＡ４は、光照射直後からの、水の接触角の低下速度が０．８２［°／Ｈｒ］となり、光照射直後から超親水化機能が発現するまでの所要時間は、光触媒体ＡＡ６の６４時間よりも短時間の５６時間程度となる。また、透過率が９１％の光触媒を含む光触媒組成物Ａ５を用いて製造された光触媒体ＡＡ５は、光照射直後からの、水の接触角の低下速度が０．９２［°／Ｈｒ］となり、光照射直後から超親水化機能が発現するまでの所要時間は、光触媒体ＡＡ６の６４時間よりも短時間の５０時間程度となる。 In addition, the photocatalyst AA3 produced using the photocatalyst composition A3 containing a photocatalyst having a transmittance of 78% has a rate of decrease in water contact angle of 1.38 [° / Hr] immediately after light irradiation. The time required from the time immediately after the light irradiation to the development of the superhydrophilic function is about 32 hours, which is shorter than 64 hours of the photocatalyst AA6. In addition, the photocatalyst AA4 produced using the photocatalyst composition A4 containing a photocatalyst having a transmittance of 66% has a rate of decrease in the contact angle of water of 0.82 [° / Hr] immediately after light irradiation, The required time from immediately after the light irradiation until the superhydrophilic function is manifested is about 56 hours, which is shorter than 64 hours of the photocatalyst AA6. In addition, the photocatalyst AA5 produced using the photocatalyst composition A5 containing a photocatalyst having a transmittance of 91% has a rate of decrease in water contact angle of 0.92 [° / Hr] immediately after light irradiation, The required time from immediately after the light irradiation until the superhydrophilic function is manifested is about 50 hours, which is shorter than 64 hours of the photocatalyst AA6.
特に、透過率が６８〜８９％の光触媒を含む光触媒組成物Ａ１〜Ａ３を用いて製造された光触媒体ＡＡ１〜ＡＡ３の実験結果から明らかなように、透過率が６８〜８９％の光触媒を含む光触媒組成物を用いて製造された光触媒体は、光照射直後からの、水の接触角の低下速度が１．０８〜１．６０［°／Ｈｒ］、好ましくは１．０８〜１．５１［°／Ｈｒ］となり、短時間のうちに超親水化機能が発現される。この理由は、光触媒の透過率が６８〜８９％であることによって、光が均一にチタニア粒子表面に到達し、すばやく光触媒活性が発現するからであると考えられる。 In particular, as apparent from the experimental results of photocatalysts AA1 to AA3 produced using photocatalyst compositions A1 to A3 containing a photocatalyst having a transmittance of 68 to 89%, the photocatalyst having a transmittance of 68 to 89% is contained. The photocatalyst produced using the photocatalyst composition has a water contact angle decreasing rate of 1.08 to 1.60 [° / Hr] immediately after light irradiation, preferably 1.08 to 1.51 [ ° / Hr], and the superhydrophilic function is developed within a short time. The reason for this is considered to be that when the transmittance of the photocatalyst is 68 to 89%, the light uniformly reaches the surface of the titania particles, and the photocatalytic activity is quickly expressed.
また、光触媒体ＡＡ１〜ＡＡ６について、アセトアルデヒドガス分解性能を測定した。なお、アセトアルデヒドガス分解性能は、アセトアルデヒドガス濃度を４５〜６５ｐｐｍに調整した試験ガスを光触媒体の光触媒塗布試験面に対する気積比が１０．６ｍ２／ｍ３となるようにテドラーバックに充填後、ブラックライトブルー蛍光ランプにて２ｍＷ／ｃｍ２の照度で連続照射し、アセトアルデヒドガス濃度の経時変化を測定した。アセトアルデヒドガス濃度は光音響ガスモニター（１４１２−５型、ＩＮＮＩＶＡ社製）にて５分間隔で測定を行った。アセトアルデヒドガス分解性能の測定結果を図４に示す。 Moreover, the acetaldehyde gas decomposition | disassembly performance was measured about photocatalyst bodies AA1-AA6. The acetaldehyde gas decomposition performance was determined by filling a test gas whose acetaldehyde gas concentration was adjusted to 45 to 65 ppm into a tedlar back so that the volume ratio of the photocatalyst to the photocatalyst coating test surface was 10.6 m 2 / m 3 , Continuous irradiation was performed with a light blue fluorescent lamp at an illuminance of 2 mW / cm 2 , and the change with time in the acetaldehyde gas concentration was measured. The acetaldehyde gas concentration was measured at intervals of 5 minutes with a photoacoustic gas monitor (1412-5 type, manufactured by INNIVA). The measurement results of the acetaldehyde gas decomposition performance are shown in FIG.
図４は、光触媒体の光照射に伴うアセトアルデヒドガス濃度の経時変化を示すグラフである。図４のグラフにおいて、横軸は光照射時間（分）を示し、縦軸はアセトアルデヒドガス濃度（ｐｐｍ）を示す。また、図４のグラフにおいて、「白丸」のプロットは光触媒体ＡＡ１の測定結果を示し、「黒丸」のプロットは光触媒体ＡＡ２の測定結果を示し、「白四角」のプロットは光触媒体ＡＡ３の測定結果を示し、「白三角」のプロットは光触媒体ＡＡ４の測定結果を示し、「黒三角」のプロットは光触媒体ＡＡ５の測定結果を示し、「バツ」のプロットは光触媒体ＡＡ６の測定結果を示す。 FIG. 4 is a graph showing a change with time of the acetaldehyde gas concentration accompanying light irradiation of the photocatalyst. In the graph of FIG. 4, the horizontal axis indicates the light irradiation time (minutes), and the vertical axis indicates the acetaldehyde gas concentration (ppm). In the graph of FIG. 4, the plot of “white circle” indicates the measurement result of the photocatalyst AA1, the plot of “black circle” indicates the measurement result of the photocatalyst AA2, and the plot of “white square” indicates the measurement of the photocatalyst AA3. The result shows a measurement result of the photocatalyst AA4, a plot of “black triangle” shows a measurement result of the photocatalyst AA5, and a plot of “X” shows a measurement result of the photocatalyst AA6. .
図４の実験結果より、透過率が６２％の従来技術の光触媒を含む光触媒組成物Ａ６を用いて製造された光触媒体ＡＡ６と比較して、透過率が６６〜９１％の光触媒を含む光触媒組成物Ａ１〜Ａ５を用いて製造された光触媒体ＡＡ１〜ＡＡ５は、光照射に伴うアセトアルデヒドガス分解性能が高い状態で維持されていることが分かる。特に、透過率が６８〜８９％の光触媒を含む光触媒組成物Ａ１〜Ａ３を用いて製造された光触媒体ＡＡ１〜ＡＡ３は、光照射に伴うアセトアルデヒドガス分解性能がより高い状態で維持されていることが分かる。 From the experimental results shown in FIG. 4, the photocatalyst composition containing a photocatalyst having a transmittance of 66 to 91% as compared with the photocatalyst AA6 produced using the photocatalyst composition A6 containing a conventional photocatalyst having a transmittance of 62%. It can be seen that the photocatalysts AA1 to AA5 produced using the products A1 to A5 are maintained in a state in which the acetaldehyde gas decomposition performance accompanying light irradiation is high. In particular, the photocatalysts AA1 to AA3 produced using the photocatalyst compositions A1 to A3 containing a photocatalyst having a transmittance of 68 to 89% are maintained in a state in which the acetaldehyde gas decomposition performance associated with light irradiation is higher. I understand.
次に、本実施形態の光触媒体１における光触媒３１の粒子形状について説明する。光触媒３１の粒子形状については、透過型電子顕微鏡（Transmission Electron Microscope、略称ＴＥＭ）、走査型電子顕微鏡（Scanning Electron Microscope、略称ＳＥＭ）にて確認することができる。図５Ａは、光触媒の粒子形状を観察したＴＥＭ写真である。図５Ａ（ａ）は１０万倍に拡大したＴＥＭ写真であり、図５Ａ（ｂ）は４０万倍に拡大したＴＥＭ写真であり、図５Ａ（ｃ）は図５Ａ（ｂ）に示すＴＥＭ写真においてチタニアおよびシリカの各部分が明確に区別できるように各部分の境界を示す境界線を付記したものである。また、図５Ｂは、光触媒の粒子形状を観察したＳＥＭ写真である。この図５Ａおよび図５Ｂに示すＴＥＭ写真およびＳＥＭ写真は、不定形状のチタニア３１１に不定形状のシリカ３１２が担持された複合型の光触媒３１の粒子形状について観察したものである。なお、図５Ａ（ｂ）および図５Ａ（ｃ）に示すＴＥＭ写真では、光触媒の１つの粒子の粒子形状が観察されており、格子状（指紋状）に観察される部分が不定形状のチタニアを示し、その周囲に存在する雲状に観察される部分が不定形状のシリカを示す。 Next, the particle shape of the photocatalyst 31 in the photocatalyst body 1 of the present embodiment will be described. The particle shape of the photocatalyst 31 can be confirmed with a transmission electron microscope (abbreviated as TEM) or a scanning electron microscope (abbreviated as SEM). FIG. 5A is a TEM photograph observing the particle shape of the photocatalyst. 5A (a) is a TEM photograph magnified 100,000 times, FIG. 5A (b) is a TEM photograph magnified 400,000 times, and FIG. 5A (c) is a TEM photograph shown in FIG. 5A (b). A boundary line indicating the boundary of each part is added so that each part of titania and silica can be clearly distinguished. FIG. 5B is an SEM photograph in which the particle shape of the photocatalyst is observed. The TEM photograph and SEM photograph shown in FIGS. 5A and 5B are obtained by observing the particle shape of the composite photocatalyst 31 in which the amorphous silica 312 is supported on the amorphous titania 311. In the TEM photographs shown in FIGS. 5A (b) and 5A (c), the particle shape of one particle of the photocatalyst is observed, and the portion observed in a lattice shape (fingerprint shape) is an irregularly shaped titania. The portion observed in the shape of a cloud present in the vicinity thereof shows an amorphous silica.
光触媒層３を構成する光触媒３１は、チタニア３１１およびシリカ３１２が、図５Ａおよび図５ＢのＴＥＭ写真およびＳＥＭ写真に示されるように、不定形状の粒子であることが好ましい。ここで、不定形状の粒子とは、球形状ではない、針状、繊維状、棒状、鱗片状、膜状などの形状を有する粒子である。 As for the photocatalyst 31 which comprises the photocatalyst layer 3, it is preferable that the titania 311 and the silica 312 are indefinite-shaped particle | grains, as the TEM photograph and SEM photograph of FIG. 5A and FIG. 5B show. Here, the irregularly shaped particles are particles having a shape such as a needle shape, a fiber shape, a rod shape, a scale shape, and a film shape, which are not spherical.
上記のような不定形状のチタニア３１１は、非晶質チタニア分散体を作製する工程において、チタン成分にカルボン酸（酢酸）を結合させる（配位させる）ことによって、不定形状のチタニアの粒子を含む非晶質チタニア分散体を生成し、これによって、不定形状のチタニア３１１とすることができる。また、不定形状のシリカ３１２は、シリカゾルを混合する工程において、そのシリカゾルとして、不定形状のシリカの粒子を含むシリカゾルを用いることによって、不定形状のシリカ３１２とすることができる。なお、不定形状のシリカ３１２とする際に用いるシリカゾルは、球状、針状、鎖状（球状粒子が鎖状に結合されたもの）のシリカ粒子がコロイド状態となっているコロイダルシリカと、シランアルコキシドまたはアルキルシリケートとを、アルコールおよび酸の存在下に加水分解反応させることによって作製することができる。 The irregularly shaped titania 311 as described above contains irregularly shaped titania particles by bonding (coordinating) a carboxylic acid (acetic acid) to a titanium component in the step of producing an amorphous titania dispersion. An amorphous titania dispersion can be produced, thereby forming an amorphous titania 311. In addition, in the step of mixing the silica sol, the amorphous silica 312 can be made into the amorphous silica 312 by using a silica sol containing amorphous particles as the silica sol. Note that the silica sol used for forming the irregular-shaped silica 312 includes colloidal silica in which spherical, needle-like, and chain-like (particles in which spherical particles are combined in a chain) are in a colloidal state, and silane alkoxide. Alternatively, it can be produced by subjecting an alkyl silicate to a hydrolysis reaction in the presence of an alcohol and an acid.
コロイダルシリカとしては市販されているものを用いることができ、たとえば、日産化学工業株式会社製のスノーテックＣ、スノーテックＵＰ、スノーテックＰＳ−Ｓなどを用いることができる。また、シランアルコキシドとしてはテトラエトキシシラン、テトラメトキシシランなどを挙げることができ、アルキルシリケートとしてはプロピルシリケート、ブチルシリケートなどを挙げることができるが、本実施形態ではテトラエトキシシランを用いる。また、アルコールとしてはエタノール、イソプロピルアルコール、メタノールなどを挙げることができるが、本実施形態ではエタノールを用いる。さらにまた、酸としては硫酸、塩酸、硝酸、ギ酸、酢酸などを挙げることができるが、本実施形態では酢酸を用いる。 As the colloidal silica, commercially available ones can be used, for example, Snow Tech C, Snow Tech UP, Snow Tech PS-S, etc. manufactured by Nissan Chemical Industries, Ltd. can be used. Examples of the silane alkoxide include tetraethoxysilane and tetramethoxysilane. Examples of the alkyl silicate include propyl silicate and butyl silicate. In this embodiment, tetraethoxysilane is used. Examples of the alcohol include ethanol, isopropyl alcohol, and methanol. In the present embodiment, ethanol is used. Furthermore, examples of the acid include sulfuric acid, hydrochloric acid, nitric acid, formic acid, and acetic acid. In this embodiment, acetic acid is used.
不定形状の粒子は、球形粒子に比べて凝集粒子の形成度合いが低いので、１つの大きな凝集粒子として振舞うことが抑制され、光の散乱を抑制することができる。したがって、光触媒３１を構成するチタニア３１１およびシリカ３１２が不定形状の粒子であることによって、光触媒３１の光散乱による白濁を防止することができ、光触媒３１を実質的に透明とすることができる。これによって、光触媒３１に対する光の入射光量を大きくすることができるので、光触媒体１に光が照射されてから超親水化機能が発現されるまでの時間を短縮することができる。また、不定形状の粒子は、球形粒子に比べて比表面積が大きいので、光触媒３１を構成するチタニア３１１およびシリカ３１２が不定形状の粒子であることによって、光触媒３１の基材２表面に対する密着性を向上させることができる。したがって、光触媒３１を構成するチタニア３１１およびシリカ３１２が不定形状の粒子であることによって、光触媒３１が基材２表面から剥離することが抑制可能となる。 Since the irregularly shaped particles have a lower degree of formation of aggregated particles than spherical particles, they can be suppressed from acting as one large aggregated particle, and light scattering can be suppressed. Therefore, since the titania 311 and the silica 312 constituting the photocatalyst 31 are particles having an indefinite shape, white turbidity due to light scattering of the photocatalyst 31 can be prevented, and the photocatalyst 31 can be made substantially transparent. Thereby, since the incident light quantity of the light with respect to the photocatalyst 31 can be enlarged, the time from when light is irradiated to the photocatalyst body 1 until a superhydrophilic function is expressed can be shortened. In addition, since the irregularly shaped particles have a larger specific surface area than the spherical particles, the titania 311 and the silica 312 constituting the photocatalyst 31 are irregularly shaped particles, so that the photocatalyst 31 adheres to the surface of the substrate 2. Can be improved. Therefore, the titania 311 and the silica 312 constituting the photocatalyst 31 are particles having an indeterminate shape, so that the photocatalyst 31 can be prevented from peeling from the surface of the substrate 2.
次に、本実施形態の光触媒体１における光触媒３１中のシリカ３１２のモル比について説明する。 Next, the molar ratio of silica 312 in the photocatalyst 31 in the photocatalyst body 1 of the present embodiment will be described.
光触媒層３を構成する光触媒３１は、チタニア３１１とシリカ３１２との全モル量に対するシリカ３１２のモル量の割合（（シリカのモル量／全モル量）×１００［％］）が、１．１６〜２．３２モル％であることが好ましい。 The photocatalyst 31 constituting the photocatalyst layer 3 has a ratio of the molar amount of silica 312 to the total molar amount of titania 311 and silica 312 ((silica molar amount / total molar amount) × 100 [%]) is 1.16. It is preferable that it is -2.32 mol%.
前述の実験において作製した光触媒体ＡＡ１〜ＡＡ６について、光触媒３１中のシリカ３１２のモル比の透過率に及ぼす影響を検討した結果を図６に示す。図６は、光触媒中のシリカのモル比と光触媒の透過率との関係を示すグラフである。図６のグラフにおいて、横軸は光触媒中のシリカのモル比（モル％）を示し、縦軸は光触媒の透過率（％）を示す。 FIG. 6 shows the results of examining the influence of the molar ratio of silica 312 in the photocatalyst 31 on the transmittance of the photocatalysts AA1 to AA6 produced in the above-described experiment. FIG. 6 is a graph showing the relationship between the molar ratio of silica in the photocatalyst and the transmittance of the photocatalyst. In the graph of FIG. 6, the horizontal axis indicates the molar ratio (mol%) of silica in the photocatalyst, and the vertical axis indicates the transmittance (%) of the photocatalyst.
図６に示す結果より、光触媒３１中のシリカ３１２のモル比が小さくなるにつれて、光触媒３１の透過率が大きくなることが分かる。すなわち、チタニア−シリカ複合型の光触媒３１において、シリカ３１２は、光触媒体１の超親水化機能を補助する役割を担うとともに、光触媒３１の透過率を調整する機能を有することが分かる。 From the results shown in FIG. 6, it can be seen that the transmittance of the photocatalyst 31 increases as the molar ratio of the silica 312 in the photocatalyst 31 decreases. That is, it can be seen that in the titania-silica composite photocatalyst 31, the silica 312 has a function of assisting the superhydrophilization function of the photocatalyst 1 and a function of adjusting the transmittance of the photocatalyst 31.
また、光触媒体ＡＡ１〜ＡＡ６について、光触媒３１中のシリカ３１２のモル比の、密着摩耗性に及ぼす影響を検討した。密着摩耗性の評価は、ＪＩＳ−Ｋ−５６６３「合成樹脂エマルジョンペイント及びシーラー」の耐洗浄性試験方法に準じて行った。具体的には、各光触媒体ＡＡ１〜ＡＡ６の表面を豚毛ブラシで擦った（摩耗した）後、表面を水で洗浄し、その後、ブラックライトブルー蛍光ランプを用いて光触媒体ＡＡ１〜ＡＡ６の表面に、２ｍＷ／ｃｍ２の照度で１９２時間光を照射し、更に表面を清浄化するとともに活性化処理した後、水との接触角の測定を行った。密着摩耗性についての検討結果を図７および図８に示す。 In addition, for the photocatalysts AA1 to AA6, the influence of the molar ratio of the silica 312 in the photocatalyst 31 on the adhesion wear was examined. The evaluation of adhesion wear was performed according to the cleaning resistance test method of JIS-K-5663 “Synthetic resin emulsion paint and sealer”. Specifically, the surface of each of the photocatalysts AA1 to AA6 was rubbed (worn) with a pig brush, and then the surface was washed with water, and then the surface of the photocatalysts AA1 to AA6 using a black light blue fluorescent lamp Then, after irradiating with light at an illuminance of 2 mW / cm 2 for 192 hours to further clean and activate the surface, the contact angle with water was measured. The examination result about adhesion wear property is shown in FIG. 7 and FIG.
図７は、光触媒体における摩耗回数と接触角との関係を示すグラフである。図７のグラフにおいて、横軸は光触媒体に対する密着摩耗回数（回）を示し、縦軸は水との接触角（°）を示す。また、図７のグラフにおいて、「黒丸」のプロットは光触媒体ＡＡ２の測定結果を示し、「バツ」のプロットは光触媒体ＡＡ６の測定結果を示す。 FIG. 7 is a graph showing the relationship between the number of wear and the contact angle in the photocatalyst. In the graph of FIG. 7, the horizontal axis indicates the number of contact wear (times) with respect to the photocatalyst, and the vertical axis indicates the contact angle (°) with water. In the graph of FIG. 7, the plot of “black circle” indicates the measurement result of the photocatalyst AA2, and the plot of “X” indicates the measurement result of the photocatalyst AA6.
図７に示す結果より、従来技術の光触媒を含む光触媒組成物Ａ６を用いて製造された光触媒体ＡＡ６は、摩耗回数が多くなるにつれて水との接触角が大きくなってしまう。すなわち、光触媒体ＡＡ６では、摩耗回数が多くなるにつれて光触媒層が摩耗して剥離され、超親水化機能が失われる。このことより、光触媒体ＡＡ６は、優れた密着摩耗性を有していないことが分かる。 From the results shown in FIG. 7, the photocatalyst AA6 produced using the photocatalyst composition A6 containing the conventional photocatalyst has a larger contact angle with water as the number of wear increases. That is, in the photocatalyst AA6, as the number of wear increases, the photocatalyst layer is worn and peeled, and the superhydrophilic function is lost. This shows that the photocatalyst AA6 does not have excellent adhesion wear properties.
これに対して、光触媒体ＡＡ２は、摩耗回数が多くなっても水との接触角がほとんど変化しない。すなわち、光触媒体ＡＡ２では、摩耗回数が多くなっても光触媒層が摩耗して剥離することなく、超親水化機能が保持される。このことより、光触媒体ＡＡ２は、優れた密着摩耗性を有していることが分かる。 On the other hand, the photocatalyst AA2 has almost no change in contact angle with water even when the number of wear increases. That is, in the photocatalyst body AA2, even if the number of wears increases, the photocatalyst layer does not wear and peel, and the superhydrophilic function is maintained. From this, it can be seen that the photocatalyst AA2 has excellent adhesion wear properties.
図８は、光触媒体における密着摩耗性を示すグラフである。図８のグラフにおいて、横軸は光触媒体の種類を示し、縦軸は水との接触角（°）を示す。なお、図８では、光触媒体ＡＡ１〜ＡＡ６の実験結果以外に、光触媒体ＳＳ１についての実験結果も示している。この光触媒体ＳＳ１は、以下のようにして製造されたものである。 FIG. 8 is a graph showing the adhesion wear resistance of the photocatalyst. In the graph of FIG. 8, the horizontal axis indicates the type of photocatalyst, and the vertical axis indicates the contact angle (°) with water. In addition, in FIG. 8, the experimental result about photocatalyst body SS1 is also shown other than the experimental result of photocatalyst body AA1-AA6. This photocatalyst SS1 is manufactured as follows.
光触媒体ＳＳ１を製造するにあたり、まず、非晶質チタニア分散体にシリカゾルを混合しないこと以外は、上記の光触媒組成物Ａ１と同様にして、アナターゼ型の結晶構造を有する不定形状のチタニアからなる光触媒が溶媒（水）中に分散された光触媒組成物Ｓ１を得た。このようにして得られた光触媒組成物Ｓ１に含まれる光触媒は、シリカが担持されていないものであり、光触媒中のシリカのモル比が「０モル％」である。 In producing the photocatalyst SS1, first, a photocatalyst composed of amorphous titania having an anatase type crystal structure is used in the same manner as the photocatalyst composition A1 except that silica sol is not mixed with the amorphous titania dispersion. A photocatalytic composition S1 in which was dispersed in a solvent (water) was obtained. The photocatalyst contained in the photocatalyst composition S1 thus obtained does not carry silica, and the molar ratio of silica in the photocatalyst is “0 mol%”.
次に、施釉タイル基材を表面温度が１００℃になるようにプレヒートした後、超音波スプレーコート法により光触媒組成物Ｓ１を塗布し、その後、５００℃で１時間焼き付けすることによって、光触媒体ＳＳ１を得ることができる。 Next, after pre-heating the glazed tile base material so that the surface temperature becomes 100 ° C., the photocatalyst composition S1 is applied by an ultrasonic spray coating method, and then baked at 500 ° C. for 1 hour, whereby the photocatalyst SS1 Can be obtained.
図８に示す結果より、従来技術の光触媒（シリカのモル比＝４０モル％）を含む光触媒組成物Ａ６を用いて製造された光触媒体ＡＡ６は、「摩耗なし」の初期状態における光照射後の水との接触角が４．５８°であるのに対して、「１２００回摩耗後」における光照射後の水との接触角が３７．８°となり、超親水化機能が失われ、優れた密着摩耗性を有していないことが分かる。 From the results shown in FIG. 8, the photocatalyst AA6 produced using the photocatalyst composition A6 containing the photocatalyst of the prior art (silica molar ratio = 40 mol%) is in the initial state of “no wear” after light irradiation. Whereas the contact angle with water is 4.58 °, the contact angle with water after light irradiation in “after 1200 times wear” is 37.8 °, and the superhydrophilic function is lost, which is excellent. It turns out that it does not have adhesion wear property.
これに対して、光触媒組成物Ａ１（光触媒中のシリカのモル比＝２．３２モル％）を用いて製造された光触媒体ＡＡ１は、「摩耗なし」の初期状態における光照射後の水との接触角が４．１°であるのに対して、「１２００回摩耗後」における光照射後の水との接触角が８．７°となり、超親水化機能が保持され、優れた密着摩耗性を有していることが分かる。また、光触媒組成物Ａ２（光触媒中のシリカのモル比＝１．１６モル％）を用いて製造された光触媒体ＡＡ２は、「摩耗なし」の初期状態における光照射後の水との接触角が６．１°であるのに対して、「１２００回摩耗後」における光照射後の水との接触角が９．４°となり、超親水化機能が保持され、優れた密着摩耗性を有していることが分かる。また、光触媒組成物Ａ３（光触媒中のシリカのモル比＝１．７４モル％）を用いて製造された光触媒体ＡＡ３は、「摩耗なし」の初期状態における光照射後の水との接触角が３．９°であるのに対して、「１２００回摩耗後」における光照射後の水との接触角が８．３°となり、超親水化機能が保持され、優れた密着摩耗性を有していることが分かる。 On the other hand, the photocatalyst AA1 produced using the photocatalyst composition A1 (molar ratio of silica in the photocatalyst = 2.32 mol%) is in an initial state of “no wear” with water after light irradiation. Whereas the contact angle is 4.1 °, the contact angle with water after light irradiation in “after 1200 times wear” is 8.7 °, and the superhydrophilic function is maintained and excellent adhesion wear properties are achieved. It can be seen that Also, the photocatalyst AA2 produced using the photocatalyst composition A2 (molar ratio of silica in the photocatalyst = 1.16 mol%) has a contact angle with water after light irradiation in the initial state of “no wear”. In contrast to 6.1 °, the contact angle with water after light irradiation in “after 1200 times wear” is 9.4 °, the superhydrophilic function is maintained, and the adhesive wear resistance is excellent. I understand that Further, the photocatalyst AA3 produced using the photocatalyst composition A3 (molar ratio of silica in the photocatalyst = 1.74 mol%) has a contact angle with water after light irradiation in the initial state of “no wear”. Whereas it is 3.9 °, the contact angle with water after light irradiation in “after 1200 times wear” is 8.3 °, the superhydrophilic function is maintained, and it has excellent wear resistance. I understand that
また、光触媒組成物Ａ４（光触媒中のシリカのモル比＝４．１モル％）を用いて製造された光触媒体ＡＡ４は、「摩耗なし」の初期状態における光照射後の水との接触角が６．１°であるのに対して、「１２００回摩耗後」における光照射後の水との接触角が７．２°となり、超親水化機能が保持され、優れた密着摩耗性を有していることが分かる。また、光触媒組成物Ａ５（光触媒中のシリカのモル比＝０．５８モル％）を用いて製造された光触媒体ＡＡ５は、「摩耗なし」の初期状態における光照射後の水との接触角が３．９°であるのに対して、「１２００回摩耗後」における光照射後の水との接触角が９．１°となり、超親水化機能が保持され、優れた密着摩耗性を有していることが分かる。さらにまた、光触媒組成物Ｓ１（光触媒中のシリカのモル比＝０モル％）を用いて製造された光触媒体ＳＳ１は、「摩耗なし」の初期状態における光照射後の水との接触角が４．５°であるのに対して、「１２００回摩耗後」における光照射後の水との接触角が８．９°となり、超親水化機能が保持され、優れた密着摩耗性を有していることが分かる。 In addition, the photocatalyst AA4 produced using the photocatalyst composition A4 (silica molar ratio in photocatalyst = 4.1 mol%) has a contact angle with water after light irradiation in the initial state of “no wear”. In contrast to 6.1 °, the contact angle with water after light irradiation in “after 1200 times wear” is 7.2 °, the superhydrophilic function is maintained, and the adhesive wear resistance is excellent. I understand that In addition, the photocatalyst AA5 produced using the photocatalyst composition A5 (silica molar ratio in the photocatalyst = 0.58 mol%) has a contact angle with water after light irradiation in the initial state of “no wear”. Whereas it is 3.9 °, the contact angle with water after light irradiation in “after 1200 times wear” is 9.1 °, the superhydrophilic function is maintained, and the adhesive wear resistance is excellent. I understand that Furthermore, the photocatalyst SS1 produced using the photocatalyst composition S1 (silica molar ratio in the photocatalyst = 0 mol%) has a contact angle with water after light irradiation of 4 in the initial state of “no wear”. Whereas the contact angle with water after light irradiation is 8.9 °, after “1200 times wear”, the superhydrophilic function is maintained, and the adhesive wear resistance is excellent. I understand that.
光触媒体ＡＡ１〜ＡＡ５，ＳＳ１は、光触媒体ＡＡ６と比較して、光触媒中のシリカのモル比が極めて小さいけれども、優れた密着摩耗性を有する。このことより、光触媒体ＡＡ１〜ＡＡ５，ＳＳ１において、シリカは、基材と結着させるバインダーとして機能するものではないと推測される。 The photocatalysts AA1 to AA5 and SS1 have excellent adhesion wear properties although the molar ratio of silica in the photocatalyst is very small compared to the photocatalyst AA6. From this, in the photocatalysts AA1 to AA5, SS1, it is presumed that silica does not function as a binder to be bound to the base material.
光触媒体ＡＡ１〜ＡＡ５，ＳＳ１が優れた密着摩耗性を有しているのは、光触媒体ＡＡ１〜ＡＡ５，ＳＳ１において光触媒が、不定形状のチタニアおよびシリカによって構成されているからであると考えられる。すなわち、不定形状の粒子は、球形粒子に比べて比表面積が大きいので、光触媒の基材表面に対する密着摩耗性を向上させることができたと考えられる。 It is considered that the photocatalysts AA1 to AA5 and SS1 have excellent adhesion wear properties because the photocatalyst in the photocatalysts AA1 to AA5 and SS1 is composed of titania and silica having an irregular shape. That is, it is considered that the irregularly shaped particles have a larger specific surface area than the spherical particles, so that the adhesion wear property of the photocatalyst to the substrate surface can be improved.
次に、本実施形態の光触媒体１における光触媒３１に対するドーピングの効果について説明する。 Next, the effect of doping on the photocatalyst 31 in the photocatalyst body 1 of the present embodiment will be described.
光触媒体１における光触媒３１は、チタニア３１１の結晶中に、アルミニウム（Ａｌ）、遷移金属元素（バナジウム（Ｖ）、ニオブ（Ｎｂ）、クロム（Ｃｒ）、マンガン（Ｍｎ）など）から選ばれる少なくとも１種のドーパントがドーピングされていてもよい。なお、本発明において、ドーパントがドーピングされた光触媒３１とは、半導体分野における「ドーピング」と同様の定義であり、ドーパントがチタニア３１１の結晶格子の１つに置換されたものであり、チタニア３１１の結晶表面のＴｉ−ＯＨ結合部分に異種物質が吸着されたもの、あるいはチタニア３１１に異種物質が単に混合されたものを指すものではない。 The photocatalyst 31 in the photocatalyst body 1 is at least 1 selected from aluminum (Al), transition metal elements (vanadium (V), niobium (Nb), chromium (Cr), manganese (Mn), etc.) in the titania 311 crystal. A seed dopant may be doped. In the present invention, the photocatalyst 31 doped with the dopant has the same definition as “doping” in the semiconductor field, and the dopant is substituted with one of the crystal lattices of the titania 311. It does not indicate that a foreign substance is adsorbed on the Ti—OH bond portion of the crystal surface, or that a foreign substance is simply mixed with titania 311.
このようなドーパントがドーピングされてなる光触媒３１により構成される光触媒層３が形成された光触媒体１は、有機物分解機能、超親水化機能が更に高められたものとなる。 The photocatalyst body 1 in which the photocatalyst layer 3 composed of the photocatalyst 31 doped with such a dopant is formed has an organic substance decomposition function and a superhydrophilic function further enhanced.
１ 光触媒体
２ 基材
３ 光触媒層
３１ 光触媒
３１１ チタニア
３１２ シリカ
DESCRIPTION OF SYMBOLS 1 Photocatalyst body 2 Base material 3 Photocatalyst layer 31 Photocatalyst 311 Titania 312 Silica
Claims (3)
前記基材の表面に形成される光触媒層であって、紫外線が照射されることによって光励起される、波長３５１ｎｍの光の透過率が６８〜８９％の光触媒を含む光触媒層と、を備え、
前記光触媒は、アナターゼ型の結晶構造を有するチタニアに非晶質のシリカが担持された複合型の光触媒であって、チタニアとシリカとの全モル量に対するシリカのモル量の割合が、１．１６〜２．３２モル％であることを特徴とする光触媒体。 A substrate;
A photocatalyst layer formed on the surface of the substrate, the photocatalyst layer containing a photocatalyst having a transmittance of 68 to 89% of light having a wavelength of 351 nm, which is photoexcited by being irradiated with ultraviolet rays ,
The photocatalyst is a composite photocatalyst in which amorphous silica is supported on titania having an anatase type crystal structure, and the ratio of the molar amount of silica to the total molar amount of titania and silica is 1.16. A photocatalyst having a content of ˜2.32 mol%.
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