JP4155760B2 - Modified titania sol composition - Google Patents

Modified titania sol composition Download PDF

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JP4155760B2
JP4155760B2 JP2002154595A JP2002154595A JP4155760B2 JP 4155760 B2 JP4155760 B2 JP 4155760B2 JP 2002154595 A JP2002154595 A JP 2002154595A JP 2002154595 A JP2002154595 A JP 2002154595A JP 4155760 B2 JP4155760 B2 JP 4155760B2
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group
modified
titania sol
photocatalyst
titania
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JP2003252625A (en
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康久 斉藤
法秀 藤基
尚久 古田
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Shinto Paint Co Ltd
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Shinto Paint Co Ltd
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Description

【0001】
【発明の属する技術分野】
本発明は、光触媒機能を有するチタニア微粒子を溶媒中に安定的に分散させた変性チタニアゾル組成物に関する。
【0002】
【従来の技術】
チタニア等の光触媒は紫外線を照射すると、光励起により価電子帯から伝導帯に電子が移行してn型半導体となり、その強力な酸化還元作用により、各種化合物の分解あるいは殺菌効果を示すことは広く知られている。チタニアのこのような機能を利用して、悪臭や空気中の有害物質、汚れの分解除去あるいは廃水処理や浄水処理、抗菌や防かびなどの環境浄化材料等として応用が報告されている。
【0003】
近年、悪臭や自動車の排気ガス等の有害物質による、居住空間や作業空間の汚染が深刻な問題となっている。また、生活排水や産業廃水などによる水質汚染、特に、現在行われている活性汚泥法などの水処理法では処理が難しい有機塩素系の溶剤や、その他農薬などによる水源の汚染なども広範囲に進行しており、環境汚染が重大な社会問題となっている。
チタニアの光触媒活性を利用し、悪臭、有害物質、環境汚染物質等の分解除去あるいは殺菌等を行い、上記問題の解決を図ることが考えられるが、実際の応用において、チタニアを粉末のままで使用されるものは僅かである。
【0004】
【発明が解決しようとする課題】
チタニアの光触媒としての応用範囲を広げ汎用化を図るためには、何らかの基体上にチタニアを担持、固定した形態をとる必要がある。チタニアを基体上に担持、固定する方法として、有機系バインダーを使用する方法が考えられるが、チタニアの光触媒作用により有機系バインダーそのものが酸化分解を受け、劣化してしまうという本質的な問題点がある。
この問題点を解決するため、チタニアの表面を、酸化分解を受け難い、アルミニウム、珪素、ジルコニウム等で代表される金属の酸化物で部分的にコーティング処理した、いわゆるマイクロカプセル化された光触媒が提案されている。具体例をあげると、特開平9−276706、特開平11−57494等がある。
【0005】
しかしながら、これらの技術で開示されたチタニアは、最終的には焼成処理され、一次粒子が多数凝集して二次粒子を形成する形の固形のチタニアである。従って、このようなチタニアを有機系バインダーと組み合わせて塗料に使用した場合、バインダーの分解による塗膜の劣化は抑えられるが、チタニアを併用しない場合と比較して、塗膜の質感が大きく変化し、塗膜の不透明性も増大し、意匠性の全く異なる外観を呈することになる。極端な場合には、光触媒機能は有するものの、得られる外観から実使用が難しいという問題点が生じる。従って上記問題点が解消されるような光触媒が強く求められている。
【0006】
【課題を解決するための手段】
本発明者らは、このような問題点を勘案し鋭意検討の結果、チタニアゾルの本来の光触媒機能、すなわち悪臭、有害物質、環境汚染物質等の分解除去あるいは殺菌等の機能をより高め、且つ上記の従来型の固形チタニアの問題点を解決した新規な光触媒を開発した。すなわち本発明は、アルコキシシランまたはその部分加水分解縮合物からの誘導体(A)(以下変性アルコキシシランと呼ぶ)を使用し、そのシラノール基の脱水反応を通じて変性されたチタニアゾル組成物において、変性アルコキシシラン(A)が下記一般式(a)で表されるアルコキシシランまたはその部分加水分解縮合物のRの一部または全部を、(1)ポリオキシアルキレン基、および(2)炭素数6〜30のアルキル基、ポリエーテル変性シリコーンオイル、あるいは水酸基含有シリコーンオイルから選ばれた一種または二種以上の官能基の両方の官能基((1)および(2))で置換させた化合物であることを特徴とする、光触媒機能を有する分散安定性に優れた液状の変性チタニアゾル組成物に関するものである。本発明の変性チタニアゾル組成物は、チタニアゾルを変性する変性アルコキシシラン(A)の量により、その機能を自由に調整することができる。また変性アルコキシシラン(A)の置換基を選択することにより、変性チタニアゾルの親水性、親油性の程度を調整することも可能である。
一般式 R Si(OR4−n (a)
:炭素数1〜8の有機基、n:0〜2、R:炭素数1〜5のアルキル基または炭素数1〜4のアシル基
【0007】
【発明の実施の形態】
本発明の変性チタニアゾル組成物について、以下に詳細に説明する。
【0008】
本発明の組成物はチタニアゾルを変性アルコキシシラン(A)(その内容は〔0009〕、〔0011〕に詳述)で変性して得られる。原料の一つであるチタニアゾルは、チタニア微粒子が水中あるいは有機溶剤中に分散安定化されたもので、酸で分散安定化が図られているもの、あるいは特殊な処理により、中性で分散安定化が図られているもの等、あらゆるチタニアゾルが含まれる。製造方法を例示すると、四塩化チタンの水溶液を加熱加水分解して得られるチタニアゾル、あるいは硫酸チタンや四塩化チタンの水溶液を加水分解し、アルカリで中和して得られる含水酸化チタンとしての沈殿凝集物を一旦ろ過した後、水あるいは有機溶剤を分散媒体として、硝酸、塩酸、あるいはアンモニア等を加え、必要により加熱下に沈殿凝集物を解謬して得られるチタニアゾル、上記沈殿凝集物の分散液を、強力な機械的分散力を用いて解謬して得られるチタニアゾル等が挙げられるが、これらに限定されない。このようにして得られるチタニアの結晶形態は光触媒能の関係からアナターゼ型が特に好ましいが、ルチル型、ブルーカイト型も十分使用が可能である。その粒子径は、光触媒能をできるだけ効率良く発揮させるため、また透明性をできるだけ確保するため、より一次粒子に近い形態で保持されているものが好ましく、具体的には400nm以下が好ましい。光触媒を具体的に例示すると、石原産業(株)のSTS−01、STS−02、テイカ工業(株)のTKS−201、TKS−202,TKS−203、TKS−251、チタン工業(株)のPC−201、PC−202等が挙げられるが、これらに限定されるものではない。また上記の含水酸化チタンの水分散液に過酸化水素水等の過酸化物を加えて、加熱反応により粒子表面にペルオキシ基を生成させた、ペルオキシチタン酸型のチタニアゾルも使用可能である。具体的に例示すると、田中転写(株)のTOゾルが挙げられる。
【0009】
もう一方の変性アルコキシシラン(A)は、前記一般式(a)で表されるアルコキシシランあるいはその部分加水分解縮合物をベースとしている。アルコキシシラン中のRは炭素数1〜8の有機基であり、Rは炭素数1〜5のアルキル基または炭素数1〜4のアシル基であり、nは0〜2である。R は、例えばメチル基、エチル基、n−プロピル基、イソプロピル基などのアルキル基、そのほかγ−クロロプロピル基、ビニル基、3,3,3−トリフロロプロピル基、γ−グリシドキシプロピル基、γ−メタクリルオキシプロピル基、γ−メルカプトプロピル基、フェニル基、3,4−エポキシシクロヘキシルエチル基などが挙げられる。Rは、例えばメチル基、エチル基、n−プロピル基、イソプロピル基、n−ブチル基、sec−ブチル基、tert−ブチル基、アセチル基などが挙げられる。
【0010】
これらのアルコキシシランの具体例としては、テトラメトキシシラン、テトラエトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、エチルトリメトキシシラン、エチルトリエトキシシラン、n−プロピルトリメトキシシラン、n−プロピルトリエトキシシラン、イソプロピルトリメトキシシラン、イソプロピルトリエトキシシラン、γ−クロロプロピルトリメトキシシラン、γ−クロロプロピルトリエトキシシラン、ビニルトリメトキシシラン、ビニルトリエトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、γ−グリシドキシプロピルトリエトキシシラン、γ−メタクリルオキシプロピルトリメトキシシラン、γ−メタクリルオキシプロピルトリエトキシシラン、γ−メルカプトプロピルトリメトキシシラン、γ−メルカプトプロピルトリエトキシシラン、フェニルトリメトキシシラン、フェニルトリエトキシシラン、3,4−エポキシシクロヘキシルエチルトリメトキシシラン、3,4−エポキシシクロヘキシルエチルトリエトキシシラン、ジメチルメトキシシラン、ジメチルジエトキシシラン、ジエチルジメトキシシラン、ジエチルジエトキシシラン、ジ−n−プロピルジメトキシシラン、ジ−n−プロピルジエトキシシラン、ジイソプロピルジメトキシシラン、ジイソプロピルジエトキシシラン、ジフェニルジメトキシシラン、ジフェニルジエトキシシラン等、さらにはこれらの部分加水分解性縮合物を挙げることができる。
【0011】
さらに本発明においては、変性チタニアゾル組成物の分散安定性をより向上させるため、あるいは塗料用途に使用した場合、塗膜中で変性チタニアゾルをできるだけ塗膜表面に濃度高く分布させるため、前記一般式(a)のR において、その一部または全部が(1)ポリオキシアルキレン基、および(2)炭素数6〜30のアルキル基、ポリエーテル変性シリコーンオイル、あるいは水酸基含有シリコーンオイルから選ばれた一種または二種以上の官能基の両方の官能基((1)および(2))で置換されたアルコキシシラン、またはその部分加水分解縮合物から誘導される変性アルコキシシラン(A)を用いて、チタニアゾルが変性される。上記の官能基を例示すると、(1)の親水性を付与するポリオキシアルキレン基については、ポリオキシエチレン基、ポリオキシプロピレン基、ポリオキシブチレン基等のポリオキシアルキレン基が挙げられる。上記ポリオキシアルキレン基は片末端がメチル基、エチル基、プロピル基等のアルキル基、アセチル基等のアシル基、あるいはアルキルフェニル基等で置換されている方がさらに好ましい。さらに(2)の親水性と親油性の両方の性能を付与する官能基については、シリコン原子に水素、メチル基、エチル基、プロピル基、エポキシ基などの官能基が一部置換したポリシロキサン鎖が、ポリオキシアルキレン基に結合した構造を有する官能基が挙げられ、また(2)の親油性を付与する官能基については、炭素数が6〜30のアルキル基、すなわちオクチル基、ステアリル基、ラウリル基等、さらには水酸基がシリコン原子に直接結合したシリコーンオイル、水酸基が炭素原子を介してシリコン原子に結合したいわゆるカルビノール変性の水酸基含有シリコーンオイル等が挙げられる。(2)の官能基は単独で使用してもよく、また二種以上併用してもかまわない。
【0012】
上記に例示した官能基をR2 に導入する方法については、相当する水酸基含有化合物を、アルコキシシランのアルコキシ基とアルコール交換反応させて得ることができる。官能基変性量については、アルコキシシラ100重量部に対し、水酸基含有化合物を30〜200重量部使用するのが好ましい。ポリシロキサン鎖が結合したポリオキシアルキレン化合物については、信越シリコーン(株)製のKF−353A、KF−354A、KF−355A、KF−615A、KF−945A、KF−6011A、東レ・ダウコーニング・シリコーン(株)製のSF8427、ST103PA、BY16−005、BY16−007、SH3746、SH8428、SH3771、SH3773M、BY16−036、BY16−027、日本ユニカー(株)製のSILWET L−7604、SILWET FZ−2161、SILWET FZ−2162、SILWET FZ−2164等のポリエーテル変性シリコーンオイルがある。
また水酸基含有のシリコーンオイルについては、信越シリコーン(株)製のKF−6001、KF−6002、KF−6003、X−22−160AS、X−22−170B、東レ・ダウコーニング・シリコーン(株)製のSF−8428、SF−8427、BY16−848、BY16−005、BY16−007、チッソ(株)製のFM−4411、FM−4421、FM−0411、FM−0421、FM−DA11、FM−DA21等がある。
【0013】
変性アルコキシシラン(A)によるチタニアゾルの変性方法については、例えばチタニアゾルに変性アルコキシシラン(A)を混合して変性する方法、あるいは変性アルコキシシラン(A)を有機溶媒に溶解した後、チタニアゾルと混合して変性する方法が挙げられるが、これらに限定されない。化学的には〔0023〕の製造例3で記載されるように、変性アルコキシシラン(A)のシラノール基の脱水反応を通じて、チタニア粒子表面が変性される。また系のpHについては、所望する変性アルコキシシラン(A)の縮合度にもよるが、縮合反応をあまり進めない場合は酸性ないし中性が好ましく、また縮合反応をある程度進める場合はアルカリ性が好ましい。変性を行う温度については、室温でも可能でありまた50〜130℃程度に加温しても問題はない。変性比率については、固形分でチタニアゾル100重量部に対し、変性アルコキシシラン(A)が5〜200重量部の範囲が特に好ましい。
【0014】
このようにして得られる本発明の変性チタニアゾル組成物は、変性前のチタニアゾルが有している光触媒機能をそのまま確保しており、且つ変性前よりも少量の使用量でも有効に光触媒機能を発揮する。また変性前のチタニアゾルと異なり、塗膜作製において有機系のバインダーと組み合わせた場合でも、その有機塗膜を劣化させることがない。
【0015】
このような機能が発現する理由は明確ではないが、一つの理由として、本発明の変性チタニアゾル組成物が塗膜中に存在する場合、チタニアの周辺には変性に使用した変性アルコキシシラン(A)が高濃度に存在しており、チタニアと塗膜バインダーが直接接触する頻度が極めて少なくなるため、塗膜バインダーがチタニアの酸化還元作用を受けず、劣化が防止されると考えられる。また本発明の変性されたチタニアゾル組成物が変性前より光触媒機能が向上する理由については、変性剤である変性アルコキシシラン(A)の作用で、チタニアが塗膜上層に濃度高く偏在するためではないかと考えるが定かではない。
【0016】
また本発明の変性チタニアゾル組成物は、変性後においても変性前の粒子状態が保持されている。そのため透明性が高く、分散安定性も良好なことから、得られる塗膜はチタニアゾルを併用しない塗膜と比較して、外観の変化がほとんどない。その意味でも本発明のチタニアゾル組成物は従来にない優れた光触媒であると言える。
【0017】
上記のとおり、従来型の光触媒と異なり、本発明の変性チタニアゾル組成物は塗膜を劣化させることがないので、塗膜形成のためのバインダーを選ぶ必要がない。従ってその用途に応じて、既存のバインダーが種々選択できる。すなわち常乾ないし強制乾燥型の塗料から、本格的な焼き付け型塗料、またバインダーの種類としては無機系塗料はもとより有機系塗料まで広がり、その適用範囲は極めて大きい。さらに変性チタニアゾル組成物の親水性、親油性を調節することにより、水性塗料から油性塗料まで広く応用できる。
【0018】
本発明のチタニアゾル組成物を用いた塗料は、建築物、構築物、金属パネル、プラスチックボード、タイル、ガラス、フィルム、モルタル板、木材、紙、布、繊維等あらゆる物品に塗装が可能である。また塗装方法は、塗装物品に応じ、ロール、刷毛、吹き付け、浸漬等、従来のあらゆる塗装方法が適応できる。
【0019】
前記の方法で得られた塗装物品は優れた光触媒機能を有し、実用面からは塗膜に付着した汚染物質を分解することによる塗膜自体の低汚染化、さらには大気中の悪臭、有害物質、環境汚染物質等の分解除去、工場廃水、生活排水、農業用水、湖沼、河川水、飲料水等に含まれる菌類、藻類、その他の微生物に対する殺菌、除去による水質浄化等応用範囲が広い。
【0020】
【実施例】
以下に、本発明について、製造例および、実施例と比較例を挙げさらに詳細に説明するが、本発明はこれらに限定されるものではない。
【0021】
〔変性アルコキシシランの製法〕
[製造例1] (変性アルコキシシラン−1の合成)
温度計、コンデンサー、撹拌機、撹拌羽根を備えた1リットルのガラス製4つ口フラスコに、下記(1)〜(4)を仕込み、適度な撹拌下で窒素置換後120℃まで昇温する。副生成物を留去しながら3時間保持した後、室温まで冷却してSiO2 含有率27%の変性アルコキシシラン−1を得た。

Figure 0004155760
【0022】
[製造例2] (変性アルコキシシラン−2の合成)
温度計、コンデンサー、撹拌機、撹拌羽根を備えた1リットルのガラス製4つ口フラスコに、下記(1)、(2)、(3)、(4)を仕込み、適度な撹拌下で窒素置換後120℃まで昇温する。副生成物を留去しながら3時間保持した後、室温まで冷却してSiO2 含有率22%の変性アルコキシシラン−2を得た。
Figure 0004155760
【0023】
〔変性チタニアゾル組成物(光触媒水分散液)の製法〕
[製造例3] (光触媒水分散液A)
温度計、コンデンサー、撹拌機、撹拌羽根を備えた1リットルのガラス製4つ口フラスコに、下記(1)、(2)を仕込む。適度な撹拌下で(3)をゆっくり投入し、分散させると共に、変性アルコキシシラン中のMPG130が結合している部分を加水分解しシラノールを発生させる。
撹拌を続けながら加熱し、60℃まで昇温する。その後(4)を約1時間にわたり徐々に加え、更に60℃で3時間保持し、チタニア粒子表面で上記シラノール基の脱水縮合を起こし、ポリシロキサン結合を形成させる。続いて減圧下でトルエンを留去して、TiO2 含有率10%、SiO2 含有率3.6%、固形分23.3%の光触媒水分散液Aを得た。
Figure 0004155760
【0024】
[製造例4] (光触媒水分散液B)
温度計、コンデンサー、撹拌機、撹拌羽根を備えた1リットルのガラス製4つ口フラスコに、製造例1と同様にして、下記(1)、(2)を仕込む。適度な撹拌下で(3)をゆっくり投入し、分散させる。
撹拌を続けながら加熱し、60℃まで昇温する。その後(4)を約1時間にわたり徐々に加え、更に60℃で3時間保持し、続いて減圧下でトルエンを留去して、TiO2 含有率9.5%、SiO2 含有率3.8%、固形分27%の光触媒水分散液Bを得た。
Figure 0004155760
【0025】
[製造例5] (光触媒水分散液C)
温度計、コンデンサー、撹拌機、撹拌羽根を備えた1リットルのガラス製4つ口フラスコに、下記(1)と(2)を仕込む。適度な撹拌下で(3)をゆっくり投入し、加熱して60℃まで昇温し、5時間保持して、続いて減圧下でトルエンを留去して、TiO2 含有率16.7%、SiO2 含有率3.7%、固形分33.3%の光触媒水分散液Cを得た。
Figure 0004155760
【0026】
[実施例1]
上記製造例の光触媒水分散液Aをスレート板上に塗布し、50℃で30分間乾燥させた後、チモールブルーの5%アセトン溶液を塗布し、50℃で10分間乾燥させて試験板を作成した。この試験板の一部に3cmの距離から15Wブラックライト(紫外線強度0.38mW/cm2 )を60分間照射した後、未照射部分との色の差を目視で判定したところ、照射部分はほとんど色が残っておらず、光触媒能により有機色素が分解されたことがわかった。
次にこの光触媒水分散液Aを「水性ハイテントップ(白)」(神東塗料(株)製のアクリルシリコン系上塗り塗料)に固形分比で30%添加したものを、リフレッシュプライマー(神東塗料(株)製のエポキシプライマー)を塗布してあるスレート板に、乾燥塗膜で30μmの厚さに塗布し、室温で1週間乾燥させて試験板を作成した。このものの光沢度は82%(60°グロス)で、光触媒を添加しない場合と光沢や色相などの外観は何ら変わるものでは無かった。このものをスーパーUV試験器(岩崎電気(株)製の促進耐光性試験機)で500時間試験したがチョーキングは見られず有機塗膜の分解が起こっていないことが確認された。
又、同じ塗料を、垂直にして上部1/3を60度に折り曲げたアルミ板に乾燥塗膜で20μmの厚さに塗布し1週間乾燥させた試験板を、尼崎市内で1年間曝露し雨だれ汚染を調べた。垂直部の汚れを試験前と比較し、ハンター色差計のΔLで表すと2.2でほとんど汚れがわからない状態であった。この事から(ΔLが約5以下であるため)光触媒能による汚染防止が発揮されていることがわかった。
【0027】
[実施例2]
上記製造例の光触媒水分散液Bについて実施例1と同様にして試験したところ、同じく光触媒能が認められ、又水性ハイテントップに添加して得られた塗膜の外観はこのものを添加しない場合と何ら変わらない結果であった。更にスーパーUV試験を行った後もチョーキングは認められず有機塗膜の分解は起こっていないことが分かった。又雨垂れ汚染想定の曝露試験でもΔL=2.0で汚染防止能が発揮されていることが認められた。
【0028】
[実施例3]
上記実施例1の光触媒水分散液Aを光触媒水分散液Cに置き換えた他は全く同様にして、光触媒能が有ること、上塗り塗料に添加しても外観が変化しない事、紫外線照射によっても有機塗膜は分解されない事、汚染防止能が有る事が確認された。この時のΔLは1.9であった。
【0029】
[比較例1]
上記実施例1の光触媒水分散液Aの代わりに、STS−01を用いた他は全く同様にして試験を行った。いずれも実施例1と同程度の光触媒能と上塗り塗料に添加した場合の外観変化は無く、汚染防止能(ΔL=3.5)も認められたが、スーパーUV試験の500時間でチョーキングが起こり、有機塗膜成分が光触媒能で分解されていることが認められた。
【0030】
[比較例2]
上記実施例1の光触媒水分散液の代わりに、TKS−203を用いた他は全く同様にして試験を行った。いずれも実施例1と同程度の光触媒能と上塗り塗料に添加した場合の外観変化は無く、汚染防止能(ΔL=4.0)も認められたが、スーパーUV試験の500時間でチョーキングが起こり、有機塗膜成分が光触媒能で分解されていることが確認された。
【0031】
[変性アルコキシシランの製法]
[製造例6] (変性アルコキシシラン−3の合成)
温度計、コンデンサー、撹拌機、撹拌羽根を備えた1リットルのガラス製4つ口フラスコに、下記(1)、(2)、(3)、(4)を仕込み、適度な撹拌下で窒素置換後120℃まで昇温する。副生成物を留去しながら3時間保持した後、室温まで冷却してSiO2 含有率24%の変性アルコキシシラン−3を得た。
Figure 0004155760
【0032】
[製造例7] (変性アルコキシシラン−4の合成)
温度計、コンデンサー、撹拌機、撹拌羽根を備えた1リットルのガラス製4つ口フラスコに、下記(1)、(2)、(3)、(4)を仕込み、適度な撹拌下で窒素置換後120℃まで昇温する。副生成物を留去しながら3時間保持した後、室温まで冷却してSiO2 含有率20%の変性アルコキシシラン−4を得た。
Figure 0004155760
(注6)FM−0411:チッソ(株)製の水酸基含有シリコーンオイル
【0033】
〔変性チタニアゾル組成物(光触媒分散液)の製法〕
[製造例8] (光触媒分散液D)
温度計、コンデンサー、撹拌機、撹拌羽根を備えた1リットルのガラス製4つ口フラスコに下記(2)を仕込む。適度な撹拌下に(1)をゆっくり投入し、60℃まで昇温して5時間保持し、TiO2 含有率16.7%、SiO2 含有率4.0%、固形分33.3%の光触媒分散液Dを得た。
Figure 0004155760
(注7)TKS−251:テイカ(株)製のアナターゼ型チタニアゾル、中性、TiO2 含有率20%、トルエン溶媒
【0034】
[製造例9] (光触媒分散液E)
温度計、コンデンサー、撹拌機、撹拌羽根を備えた1リットルのガラス製4つ口フラスコに、下記(2)を仕込む。適度な撹拌下に(1)をゆっくりと投入し、60℃まで昇温して5時間保持し、TiO2 含有率17%、SiO2 含有率2.9%、固形分32%の光触媒分散液Eを得た。
Figure 0004155760
【0035】
[製造例10] (光触媒水分散液F)
温度計、コンデンサー、撹拌機、撹拌羽根を備えた1リットルのガラス製4つ口フラスコに、下記(1)と(2)を仕込む。適度な撹拌下に(3)をゆっくり投入し、加熱して60℃まで昇温する。続いて減圧下でトルエンを留去して、5時間保持して、TiO2 含有率17.2%、SiO2 含有率3.5%、固形分31%の光触媒水分散液Fを得た。
Figure 0004155760
【0036】
[実施例4]
上記製造例の光触媒分散液Dについて実施例1と同様にして試験したところ、同じく光触媒能が認められた。
次に、メチルトリメトキシシラン100部とルチル型酸化チタン顔料25部を混合し、ビーズミルを用いてツブゲージで10μm以下まで顔料分散させたものに、酸性コロイダルシルカST−O(日産化学(株)製)33部を加え、室温で6時間混合熟成した後、上記製造例の光触媒分散液Dを100部添加してアルミ板に、乾燥塗膜で20μmの厚さに塗布し、150℃で30分焼付けを行い試験板を作製した。このものの光沢度は80%(60°グロス)で、光触媒を添加しない場合と光沢や色相などの外観は何ら変わるものでは無かった。このものをスーパーUV試験器(岩崎電気(株)製の促進耐光性試験機)で1000時間試験したが光沢や色相の変化は無く優れた耐候性を有することが分かった。又雨垂れ汚染想定の曝露試験でもΔL=1.5と優れた汚染防止能が認めら、この事から光触媒能による汚染防止が発揮されていることがわかった。
【0037】
[実施例5]
上記製造例の光触媒分散液Eについて実施例1と同様にして試験したところ、同じく光触媒能が認められた。
次に実施例4において、光触媒分散液Dを光触媒分散液Eに代えた以外は全く同様の条件で試験板を作製し試験を行った。このものの光沢度は84%(60°グロス)で、光触媒を添加しない場合と光沢や色相などの外観は何ら変わるものでは無かった。このものをスーパーUV試験器(岩崎電気(株)製の促進耐光性試験機)で1000時間試験したが光沢や色相の変化は無く優れた耐候性を有することが分かった。又雨垂れ汚染想定の曝露試験でもΔL=1.9と優れた汚染防止能が認めら、この事から光触媒能による汚染防止が発揮されていることがわかった。
【0038】
[実施例6]
上記製造例の光触媒分散液Dを「NYポリンK」(神東塗料(株)製のアクリルウレタン系上塗り塗料)に固形分比で30%添加したものを、鉄板に、乾燥塗膜で30μmの厚さに塗布し、室温で1週間乾燥させて試験板を作成した。又NYポリンKに添加して得られた塗膜の外観はこのものを添加しない場合と何ら変わらない結果であった。更にスーパーUV試験を500時間行った後もチョーキングは認められず有機塗膜の分解は起こっていないことが分かった。又雨垂れ汚染想定の曝露試験でもΔL=2.8で汚染防止能が発揮されていることが認められた。
【0039】
[実施例7]
実施例6の光触媒分散液Dを光触媒分散液Eに代えた以外は全く同様の条件で試験板を作製し試験を行った。得られた塗膜の外観はこのものを添加しない場合と何ら変わらない結果であった。更にスーパーUV試験を500時間行った後もチョーキングは認められず有機塗膜の分解は起こっていないことが分かった。又雨垂れ汚染想定の曝露試験でもΔL=3.0で汚染防止能が発揮されていることが認められた。
【0040】
[比較例3]
上記実施例6の光触媒分散液Dの代わりに、TKS−251を用いた他は全く同様にして試験を行った。光触媒を添加しない場合と比較して外観変化は無く、実施例6と同程度の光触媒能と、汚染防止能(ΔL=3.0)も認められたが、スーパーUV試験の500時間でチョーキングが起こり、有機塗膜成分が光触媒能で分解されていることが認められた。
【0041】
[実施例8]
上記製造例の光触媒水分散液Fについて実施例1と同様にして試験したところ、同じく光触媒能が認められ、又水性ハイテントップに添加して得られた塗膜の外観はこのものを添加しない場合と何ら変わらない結果であった。更にスーパーUV試験を500時間行った後もチョーキングは認められず有機塗膜の分解は起こっていないことが分かった。又雨垂れ汚染想定の曝露試験でもΔL=2.5で汚染防止能が発揮されていることが認められた。
【0042】
[比較例4]
上記実施例8の光触媒水分散液Fの代わりに、ペルオキシ型チタニアゾル濃縮液を用いた他は全く同様にして試験を行った。光触媒を添加しない場合と比較して外観変化は無く、実施例7と同程度の光触媒能と、汚染防止能(ΔL=2.7)も認められたが、スーパーUV試験の500時間でチョーキングが起こり、有機塗膜成分が光触媒能で分解されていることが認められた。
【0043】
【発明の効果】
本発明の変性アルコキシシラン(A)で変性されたチタニアゾル組成物は、塗料に応用して塗膜劣化を引き起こさず、塗膜外観を損なうことなく光触媒機能を発揮する。この事により、機能的には、塗膜に付着した汚染物質を分解することによる塗膜自体の低汚染化、さらには大気中の悪臭、有害物質、環境汚染物質等の分解除去、工場廃水、生活排水、農業用水、湖沼、河川水、飲料水等に含まれる菌類、藻類、その他の微生物の殺菌、除去による水質浄化等への応用が可能で、一方、適用用途としては、建築物、構造物、金属パネルなど各種素材のあらゆる物品に塗装が可能である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a modified titania sol composition in which titania fine particles having a photocatalytic function are stably dispersed in a solvent.
[0002]
[Prior art]
It is widely known that photocatalysts such as titania, when irradiated with ultraviolet light, transfer electrons from the valence band to the conduction band by photoexcitation to become n-type semiconductors, and show the decomposition or bactericidal effect of various compounds due to their strong redox action. It has been. Utilizing such functions of titania, it has been reported that it is used as an environmental purification material such as malodor, harmful substances in the air, decomposition and removal of dirt, waste water treatment, water purification treatment, antibacterial and antifungal.
[0003]
In recent years, contamination of living spaces and work spaces due to bad odors and harmful substances such as automobile exhaust gas has become a serious problem. In addition, water pollution due to domestic wastewater and industrial wastewater, in particular, organic chlorine solvents that are difficult to treat by the current water treatment methods such as the activated sludge method, and pollution of water sources due to other agricultural chemicals, etc. are proceeding extensively. Environmental pollution has become a serious social problem.
Using titania's photocatalytic activity, it may be possible to resolve the above problems by decomposing or removing odors, harmful substances, environmental pollutants, etc., but in actual applications, use titania as powder. Little is done.
[0004]
[Problems to be solved by the invention]
In order to expand the application range of titania as a photocatalyst and to make it versatile, it is necessary to take a form in which titania is supported and fixed on some substrate. As a method for supporting and fixing titania on a substrate, a method using an organic binder is conceivable, but the organic binder itself is subject to oxidative decomposition due to the photocatalytic action of titania and deteriorates. is there.
In order to solve this problem, a so-called microencapsulated photocatalyst is proposed in which the surface of titania is partially coated with an oxide of a metal such as aluminum, silicon, zirconium, etc., which is difficult to undergo oxidative decomposition. Has been. Specific examples include JP-A-9-276706 and JP-A-11-57494.
[0005]
However, the titania disclosed in these techniques is a solid titania that is finally baked and agglomerated many primary particles to form secondary particles. Therefore, when such titania is used in a paint in combination with an organic binder, deterioration of the paint film due to the decomposition of the binder can be suppressed, but the texture of the paint film changes greatly compared to the case where titania is not used in combination. Further, the opacity of the coating film is also increased, and an appearance with completely different design properties is exhibited. In an extreme case, there is a problem that although it has a photocatalytic function, it is difficult to actually use the resulting appearance. Accordingly, there is a strong demand for a photocatalyst that can solve the above problems.
[0006]
[Means for Solving the Problems]
As a result of diligent examination in consideration of such problems, the present inventors have further improved the original photocatalytic function of titania sol, that is, the function of decomposition and removal of odors, harmful substances, environmental pollutants, etc., or sterilization, and the above We have developed a new photocatalyst that solves the problems of conventional solid titania. That is, the present invention uses a modified alkoxysilane in a titania sol composition modified by dehydration reaction of silanol groups using an alkoxysilane or a derivative (A) (hereinafter referred to as a modified alkoxysilane) from a partially hydrolyzed condensate thereof. (A) is an alkoxysilane represented by the following general formula (a) or a part or all of R 2 of the partially hydrolyzed condensate thereof, (1) a polyoxyalkylene group, and (2) carbon number 6-30. A compound substituted with both functional groups ((1) and (2)) of one or two or more functional groups selected from alkyl groups, polyether-modified silicone oils, or hydroxyl group-containing silicone oils The present invention relates to a liquid modified titania sol composition having a photocatalytic function and excellent dispersion stability. The function of the modified titania sol composition of the present invention can be freely adjusted by the amount of the modified alkoxysilane (A) that modifies the titania sol. It is also possible to adjust the degree of hydrophilicity and lipophilicity of the modified titania sol by selecting a substituent of the modified alkoxysilane (A).
General formula R 1 n Si (OR 2 ) 4-n (a)
R 1 : an organic group having 1 to 8 carbon atoms, n: 0 to 2, R 2 : an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms
DETAILED DESCRIPTION OF THE INVENTION
The modified titania sol composition of the present invention will be described in detail below.
[0008]
The composition of the present invention is obtained by modifying titania sol with a modified alkoxysilane (A) (the contents of which are described in detail in [0009] and [0011]). The titania sol, one of the raw materials, is a dispersion in which titania fine particles are dispersed and stabilized in water or an organic solvent. The dispersion is stabilized with acid, or is neutral and stabilized by special treatment. All titania sols are included, such as Examples of production methods include titania sol obtained by hydrolyzing an aqueous solution of titanium tetrachloride, or precipitation aggregation as hydrous titanium oxide obtained by hydrolyzing an aqueous solution of titanium sulfate or titanium tetrachloride and neutralizing with an alkali. Once filtered, the titania sol obtained by adding nitric acid, hydrochloric acid, ammonia, or the like, using water or an organic solvent as a dispersion medium, and dissolving the precipitate aggregate under heating, if necessary, a dispersion of the above precipitate aggregate These include, but are not limited to, titania sols obtained by unwinding using a strong mechanical dispersion force. The crystal form of titania thus obtained is particularly preferably anatase type from the viewpoint of photocatalytic ability, but rutile type and blue kite type can also be sufficiently used. In order to exhibit the photocatalytic ability as efficiently as possible and to ensure transparency as much as possible, the particle diameter is preferably held in a form closer to the primary particles, and specifically, 400 nm or less is preferable. Specific examples of the photocatalyst include STS-01, STS-02 of Ishihara Sangyo Co., Ltd., TKS-201, TKS-202, TKS-203, TKS-251 of Tika Kogyo Co., Ltd. PC-201, PC-202, etc. are mentioned, but it is not limited to these. Further, a peroxy titanic acid type titania sol in which a peroxide such as hydrogen peroxide water is added to the aqueous dispersion of hydrous titanium oxide and a peroxy group is generated on the particle surface by a heating reaction can also be used. Specifically, the TO sol of Tanaka Transcription Co., Ltd. can be mentioned.
[0009]
The other modified alkoxysilane (A) is based on the alkoxysilane represented by the general formula (a) or a partially hydrolyzed condensate thereof. R 1 in alkoxysilane is an organic group having 1 to 8 carbon atoms, R 2 is an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms, and n is 0 to 2. R 1 is, for example, an alkyl group such as a methyl group, ethyl group, n-propyl group, isopropyl group, γ-chloropropyl group, vinyl group, 3,3,3-trifluoropropyl group, γ-glycidoxypropyl Group, γ-methacryloxypropyl group, γ-mercaptopropyl group, phenyl group, 3,4-epoxycyclohexylethyl group, and the like. Examples of R 2 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, and an acetyl group.
[0010]
Specific examples of these alkoxysilanes include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxy. Silane, isopropyltrimethoxysilane, isopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ- Glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane γ-mercaptopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, 3,4-epoxycyclohexylethyltriethoxysilane, dimethylmethoxysilane, dimethyldiethoxysilane, diethyl Dimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, etc. Degradable condensates can be mentioned.
[0011]
Furthermore, in the present invention, in order to further improve the dispersion stability of the modified titania sol composition, or to distribute the modified titania sol as high as possible on the coating film surface in the coating film when used in coatings, the above general formula ( A part or all of R 2 in a) is selected from (1) a polyoxyalkylene group, and (2) an alkyl group having 6 to 30 carbon atoms, a polyether-modified silicone oil, or a hydroxyl group-containing silicone oil. Or a titania sol using an alkoxysilane substituted with both functional groups ((1) and (2)) of two or more functional groups, or a modified alkoxysilane (A) derived from a partially hydrolyzed condensate thereof. Is denatured. When the above functional group is exemplified, the polyoxyalkylene group imparting hydrophilicity (1) includes polyoxyalkylene groups such as a polyoxyethylene group, a polyoxypropylene group, and a polyoxybutylene group. It is more preferable that one end of the polyoxyalkylene group is substituted with an alkyl group such as a methyl group, an ethyl group or a propyl group, an acyl group such as an acetyl group, or an alkylphenyl group. Furthermore, regarding the functional group (2) that imparts both hydrophilic and lipophilic performance, a polysiloxane chain in which functional groups such as hydrogen, methyl group, ethyl group, propyl group, and epoxy group are partially substituted on the silicon atom Are functional groups having a structure bonded to a polyoxyalkylene group, and the functional group imparting lipophilicity of (2) is an alkyl group having 6 to 30 carbon atoms, that is, an octyl group, a stearyl group, Examples thereof include silicone oil in which a lauryl group and the like have a hydroxyl group directly bonded to a silicon atom, and a so-called carbinol-modified hydroxyl group-containing silicone oil in which a hydroxyl group is bonded to a silicon atom through a carbon atom. The functional group (2) may be used alone or in combination of two or more.
[0012]
About the method of introduce | transducing the functional group illustrated above into R < 2 >, the corresponding hydroxyl-containing compound can be obtained by carrying out alcohol exchange reaction with the alkoxy group of alkoxysilane. About the functional group modification amount, it is preferable to use 30 to 200 parts by weight of the hydroxyl group-containing compound with respect to 100 parts by weight of alkoxysila. For polyoxyalkylene compounds to which polysiloxane chains are bonded, KF-353A, KF-354A, KF-355A, KF-615A, KF-945A, KF-6011A, Toray Dow Corning Silicone manufactured by Shin-Etsu Silicone Co., Ltd. SF8427, ST103PA, BY16-005, BY16-007, SH3746, SH8428, SH3771, SH3773M, BY16-036, BY16-027, SILWET L-7604, SILWET FZ-2161 manufactured by Nihon Unicar Co., Ltd. There are polyether-modified silicone oils such as SILWET FZ-2162 and SILWET FZ-2164.
For silicone oils containing hydroxyl groups, KF-6001, KF-6002, KF-6003, X-22-160AS, X-22-170B manufactured by Shin-Etsu Silicone Co., Ltd., manufactured by Toray Dow Corning Silicone Co., Ltd. SF-8428, SF-8427, BY16-848, BY16-005, BY16-007, manufactured by Chisso Corporation, FM-4411, FM-4421, FM-0411, FM-0421, FM-DA11, FM-DA21 Etc.
[0013]
As for the modification method of the titania sol with the modified alkoxysilane (A), for example, a method in which the modified alkoxysilane (A) is mixed with the titania sol for modification, or the modified alkoxysilane (A) is dissolved in an organic solvent and then mixed with the titania sol. However, it is not limited to these. Chemically, as described in Production Example 3 of [0023], the surface of titania particles is modified through a dehydration reaction of a silanol group of the modified alkoxysilane (A). The pH of the system depends on the desired degree of condensation of the modified alkoxysilane (A), but is preferably acidic to neutral when the condensation reaction is not advanced so much, and is preferably alkaline when the condensation reaction is advanced to some extent. The temperature at which denaturation is performed can be room temperature, and even if it is heated to about 50 to 130 ° C., there is no problem. The modification ratio is particularly preferably in the range of 5 to 200 parts by weight of the modified alkoxysilane (A) with respect to 100 parts by weight of the titania sol as a solid content.
[0014]
The modified titania sol composition of the present invention thus obtained maintains the photocatalytic function of the titania sol before modification as it is, and exhibits the photocatalytic function effectively even in a smaller amount used than before modification. . Further, unlike the titania sol before modification, even when combined with an organic binder in coating film production, the organic coating film is not deteriorated.
[0015]
The reason why such a function is manifested is not clear, but as one reason, when the modified titania sol composition of the present invention is present in the coating film, the modified alkoxysilane (A) used for modification around the titania. Is present in a high concentration, and the frequency with which titania and the coating film binder are in direct contact with each other is extremely low. Therefore, it is considered that the coating film binder does not receive the redox action of titania and the deterioration is prevented. The reason that the photocatalytic function of the modified titania sol composition of the present invention is improved from that before the modification is not that titania is unevenly distributed in the upper layer of the coating film due to the action of the modified alkoxysilane (A) as a modifier. I'm not sure.
[0016]
Further, the modified titania sol composition of the present invention maintains the particle state before modification even after modification. Therefore, since the transparency is high and the dispersion stability is good, the resulting coating film has almost no change in appearance as compared with a coating film not using titania sol. In that sense, it can be said that the titania sol composition of the present invention is an unprecedented excellent photocatalyst.
[0017]
As described above, unlike the conventional photocatalyst, the modified titania sol composition of the present invention does not deteriorate the coating film, so there is no need to select a binder for forming the coating film. Therefore, various existing binders can be selected according to the application. In other words, the range of coatings from ordinary drying or forced drying to full-scale baking type coatings and inorganic coatings as well as organic coatings is widened, and the application range is extremely large. Furthermore, by adjusting the hydrophilicity and lipophilicity of the modified titania sol composition, it can be widely applied from water-based paints to oil-based paints.
[0018]
The paint using the titania sol composition of the present invention can be applied to all articles such as buildings, structures, metal panels, plastic boards, tiles, glass, films, mortar boards, wood, paper, cloth, and fibers. Moreover, the coating method can apply all the conventional coating methods, such as a roll, a brush, spraying, and immersion, according to a coated article.
[0019]
The coated article obtained by the above method has an excellent photocatalytic function, and from the practical aspect, it reduces the pollution of the coating film itself by decomposing the contaminants adhering to the coating film. It has a wide range of applications such as decomposition and removal of substances and environmental pollutants, sterilization of fungi, algae and other microorganisms contained in factory wastewater, domestic wastewater, agricultural water, lakes, river water, drinking water, etc., and water purification by removal.
[0020]
【Example】
Hereinafter, the present invention will be described in more detail with reference to production examples, examples and comparative examples, but the present invention is not limited thereto.
[0021]
[Production method of modified alkoxysilane]
[Production Example 1] (Synthesis of modified alkoxysilane-1)
The following (1) to (4) are charged into a 1-liter glass four-necked flask equipped with a thermometer, a condenser, a stirrer, and a stirring blade, and heated to 120 ° C. after nitrogen substitution under moderate stirring. The mixture was kept for 3 hours while distilling off the by-products, and then cooled to room temperature to obtain modified alkoxysilane-1 having a SiO 2 content of 27%.
Figure 0004155760
[0022]
[Production Example 2] (Synthesis of modified alkoxysilane-2)
The following (1), (2), (3), and (4) are charged into a 1-liter glass four-necked flask equipped with a thermometer, condenser, stirrer, and stirring blade, and nitrogen is replaced under moderate stirring. Thereafter, the temperature is raised to 120 ° C. The mixture was kept for 3 hours while distilling out the by-products, and then cooled to room temperature to obtain modified alkoxysilane-2 having a SiO 2 content of 22%.
Figure 0004155760
[0023]
[Production method of modified titania sol composition (photocatalyst aqueous dispersion)]
[Production Example 3] (Photocatalyst aqueous dispersion A)
The following (1) and (2) are charged into a 1-liter glass four-necked flask equipped with a thermometer, a condenser, a stirrer, and a stirring blade. (3) is slowly added and dispersed under moderate agitation, and the portion of the modified alkoxysilane to which MPG130 is bonded is hydrolyzed to generate silanol.
Heat while continuing stirring and raise the temperature to 60 ° C. Thereafter, (4) is gradually added over about 1 hour and further maintained at 60 ° C. for 3 hours to cause dehydration condensation of the silanol groups on the surface of the titania particles to form polysiloxane bonds. Subsequently, toluene was distilled off under reduced pressure to obtain a photocatalyst water dispersion A having a TiO 2 content of 10%, a SiO 2 content of 3.6%, and a solid content of 23.3%.
Figure 0004155760
[0024]
[Production Example 4] (Photocatalyst aqueous dispersion B)
In the same manner as in Production Example 1, the following (1) and (2) are charged into a 1 liter glass four-necked flask equipped with a thermometer, a condenser, a stirrer, and a stirring blade. (3) is slowly charged under moderate stirring and dispersed.
Heat while continuing stirring and raise the temperature to 60 ° C. Thereafter, (4) was gradually added over about 1 hour, and further maintained at 60 ° C. for 3 hours, and then toluene was distilled off under reduced pressure to obtain a TiO 2 content of 9.5% and a SiO 2 content of 3.8. %, And a photocatalyst water dispersion B having a solid content of 27% was obtained.
Figure 0004155760
[0025]
[Production Example 5] (Photocatalyst aqueous dispersion C)
The following (1) and (2) are charged into a 1-liter glass four-necked flask equipped with a thermometer, a condenser, a stirrer, and a stirring blade. (3) is slowly added under moderate stirring, heated to 60 ° C., held for 5 hours, and then toluene is distilled off under reduced pressure to obtain a TiO 2 content of 16.7%, A photocatalyst water dispersion C having a SiO 2 content of 3.7% and a solid content of 33.3% was obtained.
Figure 0004155760
[0026]
[Example 1]
The photocatalyst aqueous dispersion A of the above production example is applied on a slate plate, dried at 50 ° C. for 30 minutes, then coated with 5% acetone solution of thymol blue, and dried at 50 ° C. for 10 minutes to prepare a test plate. did. A portion of this test plate was irradiated with 15 W black light (ultraviolet light intensity 0.38 mW / cm 2 ) from a distance of 3 cm for 60 minutes, and then the color difference from the unirradiated portion was visually determined. It was found that no color remained and the organic dye was decomposed by the photocatalytic ability.
Next, this photocatalyst aqueous dispersion A was added to “Aqueous High Ten Top (White)” (acrylic silicon-based top coat made by Shinto Paint Co., Ltd.) at a solid content ratio of 30%, and a refresh primer (Shinto Paint) A test plate was prepared by coating a slate plate coated with (Epoxy Primer Co., Ltd.) to a thickness of 30 μm with a dry coating film and drying at room temperature for 1 week. The glossiness of this product was 82% (60 ° gloss), and the appearance such as gloss and hue was not different from that when no photocatalyst was added. This was tested with a super UV tester (accelerated light resistance tester manufactured by Iwasaki Electric Co., Ltd.) for 500 hours, but no choking was observed and it was confirmed that the organic coating was not decomposed.
In addition, a test plate, which was applied to an aluminum plate with the upper 1/3 bent vertically at 60 degrees and dried to a thickness of 20 μm and dried for one week, was exposed in Amagasaki City for a year. We examined raindrop contamination. When the dirt on the vertical part was compared with that before the test and expressed by ΔL of the Hunter color difference meter, it was in a state where the dirt was hardly recognized at 2.2. From this fact, it was found that the prevention of contamination by the photocatalytic ability was exhibited (because ΔL was about 5 or less).
[0027]
[Example 2]
When the photocatalyst aqueous dispersion B of the above production example was tested in the same manner as in Example 1, the photocatalytic ability was also observed, and the appearance of the coating film obtained by adding to the aqueous high tentop was not added. The result was no different. Furthermore, after conducting the super UV test, it was found that no chalking was observed and the organic coating was not decomposed. Also, in the exposure test assuming raindrop contamination, it was confirmed that the anti-contamination ability was exhibited at ΔL = 2.0.
[0028]
[Example 3]
Except that the photocatalyst aqueous dispersion A in Example 1 was replaced with the photocatalyst aqueous dispersion C, the photocatalytic water dispersion C had photocatalytic activity, the appearance did not change even when added to the top coating, and the organic matter was also irradiated by UV irradiation. It was confirmed that the coating film was not decomposed and had the ability to prevent contamination. ΔL at this time was 1.9.
[0029]
[Comparative Example 1]
The test was performed in exactly the same manner except that STS-01 was used instead of the photocatalyst aqueous dispersion A of Example 1. In both cases, the photocatalytic ability comparable to that of Example 1 and no change in appearance when added to the top coating, and the ability to prevent contamination (ΔL = 3.5) were observed, but choking occurred in 500 hours of the super UV test. It was confirmed that the organic coating film component was decomposed by photocatalytic activity.
[0030]
[Comparative Example 2]
The test was performed in exactly the same manner except that TKS-203 was used instead of the photocatalyst aqueous dispersion of Example 1 above. In both cases, the photocatalytic ability comparable to that of Example 1 and no change in appearance when added to the top coating, and the ability to prevent contamination (ΔL = 4.0) were observed, but choking occurred in 500 hours of the super UV test. It was confirmed that the organic coating component was decomposed by photocatalytic activity.
[0031]
[Production method of modified alkoxysilane]
[Production Example 6] (Synthesis of Modified Alkoxysilane-3)
The following (1), (2), (3), and (4) are charged into a 1-liter glass four-necked flask equipped with a thermometer, condenser, stirrer, and stirring blade, and nitrogen is replaced under moderate stirring. Thereafter, the temperature is raised to 120 ° C. The mixture was kept for 3 hours while distilling off the by-products, and then cooled to room temperature to obtain modified alkoxysilane-3 having a SiO 2 content of 24%.
Figure 0004155760
[0032]
[Production Example 7] (Synthesis of modified alkoxysilane-4)
The following (1), (2), (3), and (4) are charged into a 1-liter glass four-necked flask equipped with a thermometer, condenser, stirrer, and stirring blade, and nitrogen is replaced under moderate stirring. Thereafter, the temperature is raised to 120 ° C. The mixture was kept for 3 hours while distilling off the by-products, and then cooled to room temperature to obtain a modified alkoxysilane-4 having a SiO 2 content of 20%.
Figure 0004155760
(Note 6) FM-0411: Silicone oil containing hydroxyl group manufactured by Chisso Corporation
[Production method of modified titania sol composition (photocatalyst dispersion)]
[Production Example 8] (Photocatalyst dispersion D)
The following (2) is charged into a 1-liter glass four-necked flask equipped with a thermometer, a condenser, a stirrer, and a stirring blade. (1) is slowly added under moderate stirring, and the temperature is raised to 60 ° C. and maintained for 5 hours. The TiO 2 content is 16.7%, the SiO 2 content is 4.0%, and the solid content is 33.3%. Photocatalyst dispersion D was obtained.
Figure 0004155760
(Note 7) TKS-251: Anatase-type titania sol manufactured by Teika Co., Ltd., neutral, TiO 2 content 20%, toluene solvent
[Production Example 9] (Photocatalyst dispersion E)
The following (2) is charged into a 1-liter glass four-necked flask equipped with a thermometer, a condenser, a stirrer, and a stirring blade. (1) is slowly added under moderate stirring, the temperature is raised to 60 ° C. and maintained for 5 hours, and the photocatalyst dispersion liquid has a TiO 2 content of 17%, a SiO 2 content of 2.9%, and a solid content of 32%. E was obtained.
Figure 0004155760
[0035]
[Production Example 10] (Photocatalyst aqueous dispersion F)
The following (1) and (2) are charged into a 1-liter glass four-necked flask equipped with a thermometer, a condenser, a stirrer, and a stirring blade. (3) is slowly added under moderate stirring and heated to 60 ° C. Subsequently, toluene was distilled off under reduced pressure and maintained for 5 hours to obtain a photocatalyst water dispersion F having a TiO 2 content of 17.2%, a SiO 2 content of 3.5% and a solid content of 31%.
Figure 0004155760
[0036]
[Example 4]
When the photocatalyst dispersion D of the above production example was tested in the same manner as in Example 1, the photocatalytic ability was also recognized.
Next, 100 parts of methyltrimethoxysilane and 25 parts of rutile-type titanium oxide pigment were mixed, and the pigment was dispersed to 10 μm or less using a bead mill with an acid colloidalsilka ST-O (Nissan Chemical Co., Ltd. ) After adding 33 parts and mixing and aging at room temperature for 6 hours, 100 parts of the photocatalyst dispersion D of the above production example was added and applied to an aluminum plate to a thickness of 20 μm by dry coating, and at 150 ° C. for 30 minutes. Baking was performed to prepare a test plate. The glossiness of this product was 80% (60 ° gloss), and the appearance such as gloss and hue was not different from that when no photocatalyst was added. This product was tested for 1000 hours with a super UV tester (accelerated light resistance tester manufactured by Iwasaki Electric Co., Ltd.), but it was found that there was no change in gloss or hue and excellent weather resistance. In addition, in an exposure test assuming raindrop contamination, ΔL = 1.5 and an excellent anti-contamination ability were recognized. From this fact, it was found that the anti-contamination by the photocatalytic ability was exhibited.
[0037]
[Example 5]
When the photocatalyst dispersion E of the above production example was tested in the same manner as in Example 1, the photocatalytic ability was also recognized.
Next, a test plate was prepared and tested under the same conditions as in Example 4 except that the photocatalyst dispersion D was replaced with the photocatalyst dispersion E. The glossiness of this product was 84% (60 ° gloss), and the appearance such as gloss and hue was not different from that when no photocatalyst was added. This product was tested for 1000 hours with a super UV tester (accelerated light resistance tester manufactured by Iwasaki Electric Co., Ltd.), but it was found that there was no change in gloss or hue and excellent weather resistance. In addition, in an exposure test assuming raindrop contamination, ΔL = 1.9 and an excellent anti-contamination ability were recognized, and it was found that the anti-contamination by photocatalytic ability was exhibited.
[0038]
[Example 6]
The photocatalyst dispersion liquid D of the above production example was added to “NY POLIN K” (acrylic urethane-based topcoat paint manufactured by Shinto Paint Co., Ltd.) at a solid content ratio of 30%, and the dry coating film was 30 μm on an iron plate. It was applied to a thickness and dried at room temperature for 1 week to prepare a test plate. Also, the appearance of the coating film obtained by adding to NY porin K was the same as the case where this was not added. Further, even after the super UV test was conducted for 500 hours, no choking was observed and it was found that the organic coating was not decomposed. Also, in the exposure test assuming raindrop contamination, it was found that the ability to prevent contamination was exhibited at ΔL = 2.8.
[0039]
[Example 7]
A test plate was produced and tested under exactly the same conditions except that the photocatalyst dispersion D of Example 6 was replaced with the photocatalyst dispersion E. The appearance of the obtained coating film was the same result as when this was not added. Further, even after the super UV test was conducted for 500 hours, no choking was observed and it was found that the organic coating was not decomposed. Also, in the exposure test assuming raindrop contamination, it was found that the ability to prevent contamination was exhibited at ΔL = 3.0.
[0040]
[Comparative Example 3]
The test was performed in exactly the same manner except that TKS-251 was used instead of the photocatalyst dispersion D of Example 6. There was no change in appearance compared to the case where no photocatalyst was added, and the same photocatalytic ability and contamination prevention ability (ΔL = 3.0) as in Example 6 were observed, but choking was observed in 500 hours of the super UV test. It was observed that the organic coating component was decomposed by photocatalytic activity.
[0041]
[Example 8]
When the photocatalyst aqueous dispersion F of the above production example was tested in the same manner as in Example 1, the photocatalytic ability was also observed, and the appearance of the coating film obtained by adding to the aqueous high tentop was not added. The result was no different. Further, even after the super UV test was conducted for 500 hours, no choking was observed and it was found that the organic coating was not decomposed. Also, in the exposure test assuming raindrop contamination, it was found that the ability to prevent contamination was exhibited at ΔL = 2.5.
[0042]
[Comparative Example 4]
The test was performed in exactly the same manner except that a peroxy-type titania sol concentrate was used instead of the photocatalyst aqueous dispersion F of Example 8. There was no change in appearance as compared with the case where no photocatalyst was added, and the same photocatalytic ability and antifouling ability (ΔL = 2.7) as in Example 7 were observed, but choking was observed in 500 hours of the super UV test. It was observed that the organic coating component was decomposed by photocatalytic activity.
[0043]
【The invention's effect】
The titania sol composition modified with the modified alkoxysilane (A) of the present invention is applied to a paint and does not cause deterioration of the paint film, and exhibits a photocatalytic function without impairing the paint film appearance. By this, functionally, the contamination of the coating film itself is reduced by decomposing the contaminants attached to the coating film, and further, the decomposition and removal of bad odors, harmful substances and environmental pollutants in the atmosphere, factory wastewater, It can be applied to water purification by disinfection and removal of fungi, algae and other microorganisms contained in domestic wastewater, agricultural water, lakes, river water, drinking water, etc. It can be applied to all kinds of materials such as objects and metal panels.

Claims (2)

アルコキシシランまたはその部分加水分解縮合物からの誘導体(A)を使用し、そのシラノール基の脱水反応を通じて変性されたチタニアゾル組成物において、誘導体(A)が下記一般式で表されるアルコキシシランまたはその部分加水分解縮合物のRの一部または全部を、(1)ポリオキシアルキレン基、および(2)炭素数6〜30のアルキル基、ポリエーテル変性シリコーンオイル、あるいは水酸基含有シリコーンオイルから選ばれた一種または二種以上の官能基の両方の官能基((1)および(2))で置換させた化合物であることを特徴とする、光触媒機能を有する分散安定性に優れた液状の変性チタニアゾル組成物。
Si(OR4−n
:炭素数1〜8の有機基、n:0〜2、R:炭素数1〜5のアルキル基または炭素数1〜4のアシル基
In a titania sol composition modified using alkoxysilane or its derivative (A) from a partially hydrolyzed condensate thereof through a dehydration reaction of its silanol group, the derivative (A) is an alkoxysilane represented by the following general formula or its Part or all of R 2 of the partially hydrolyzed condensate is selected from (1) a polyoxyalkylene group, and (2) an alkyl group having 6 to 30 carbon atoms, a polyether-modified silicone oil, or a hydroxyl group-containing silicone oil. A liquid modified titania sol having a photocatalytic function and excellent in dispersion stability, characterized by being a compound substituted with both functional groups ((1) and (2)) of one or more functional groups Composition.
R 1 n Si (OR 2 ) 4-n
R 1 : an organic group having 1 to 8 carbon atoms, n: 0 to 2, R 2 : an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms
チタニアゾル100重量部に対して誘導体(A)が5〜200重量部である、請求項1に記載の変性チタニアゾル組成物。  The modified titania sol composition according to claim 1, wherein the derivative (A) is 5 to 200 parts by weight with respect to 100 parts by weight of the titania sol.
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