JP4163920B2 - Method for producing titanium alkoxide hydrolysis-condensation product and coating agent for forming gradient film - Google Patents

Description

【００２０】
（式中、Ｒ¹は水素原子またはメチル基、Ｒ²は一価の炭化水素基を示す。）
で表されるエチレン性不飽和単量体と、（ｂ）一般式（II）
【００２１】
【化４】

【００２２】
（式中、Ｒ³は水素原子またはメチル基、Ａは炭素数１〜４のアルキレン基、Ｒ⁴はメチル基又はエチル基を示す。）
で表されるエチレン性不飽和単量体との共重合体である上記（３）または（４）項に記載の方法、
【００２３】
（６）（Ａ）成分の光散乱強度が８，０００〜３００，０００ｃｐｓである上記（３）、（４）または（５）項に記載の方法、
（７）有機材料上に、上記（３）ないし（６）項のいずれか１項に記載の方法を用いて有機−無機複合傾斜膜を形成し、かつ該膜の表面を実質上チタン酸化物成分により構成することを特徴とする構造体の製造方法、
（８）有機−無機複合傾斜膜上に、光触媒活性材料層を設ける上記（７）項に記載の方法、
を提供するものである。
【００２４】
【発明の実施の形態】
本発明のチタンアルコキシド加水分解縮合物の製造方法においては、チタンテトラアルコキシドを有機溶媒中で、通常酸性触媒の存在下に、加水分解−縮合反応させて、チタンアルコキシド加水分解縮合物を製造する。
【００２５】
前記チタンテトラアルコキシドとしては、アルコキシル基の炭素数が１〜４のチタンテトラアルコキシドが用いられる。このチタンテトラアルコキシドにおいては、４つのアルコキシル基は、たがいに同一でも異なっていてもよいが、入手の容易さなどの点から、同一のものが好ましく用いられる。該チタンテトラアルコキシドの例としては、チタンテトラメトキシド、チタンテトラエトキシド、チタンテトラ−ｎ−プロポキシド、チタンテトライソプロポキシド、チタンテトラ−ｎ−ブトキシド、チタンテトライソブトキシド、チタンテトラ−sec−ブトキシドおよびチタンテトラ−tert−ブトキシドが挙げられる。これらは１種を単独で用いてもよいし、２種以上を組み合わせて用いてもよい。
【００２６】
一方、有機溶媒としては、炭素数３以上のエーテル系酸素を有するアルコール類が、加水分解−縮合反応の制御および縮合物の安定化の点から好ましい。この炭素数３以上のエーテル系酸素を有するアルコール類としては、チタンテトラアルコキシドに対して相互作用を有する溶剤、例えばエチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノプロピルエーテル、エチレングリコールモノブチルエーテルなどのセロソルブ系溶剤、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノプロピルエーテル、ジエチレングリコールモノブチルエーテル、プロピレングリコールモノメチルエーテル、プロピレングリコールモノエチルエーテル、プロピレングリコールモノプロピルエーテル、プロピレングリコールモノブチルエーテルなどを挙げることができる。これらの中で、当該チタンアルコキシド縮合物をコーティング剤に用いた際のコーティング後の乾燥速度を考慮するとセロソルブ系溶剤が好ましい。これらの溶剤は１種を単独で用いてもよいし、２種以上を組み合わせて用いてもよい。
【００２７】
このような炭素数３以上のエーテル系酸素を有するアルコール類を溶媒として用いることにより、チタンアルコキシドが該溶媒と相互作用し、安定化する。通常チタンアルコキシドを安定化させるには、β−ジケトン構造をもつ化合物が使用される場合があるが、このものは沸点が高いため、コーティング剤成分として含まれると、揮発しにくい上、安定化効果が高すぎて膜中に残存しやすいという問題がある。これに対し、本発明で用いる前記アルコール類は、比較的沸点が低く、溶媒中においては、チタン原子と配位−脱離の平衡状態となり、安定化に寄与するものの、製膜して乾燥後は速やかに脱離が進行して残存しにくいという利点がある。
【００２８】
また、前記の炭素数３以上のエーテル系酸素を有するアルコール類を溶媒として用いることにより、反応時のチタンアルコキシドの加水分解縮合物の大きさを制御することができる。
【００２９】
チタンテトラアルコキシドの加水分解−縮合反応は、チタンテトラアルコキシドに対し、好ましくは４〜２０倍モル、より好ましくは５〜１２倍モルの前記アルコール類と、好ましくは０．５以上４倍モル未満、より好ましくは１〜３．０倍モルの水を用い、塩酸、硫酸、硝酸などの酸性触媒の存在下、通常０〜７０℃、好ましくは２０〜５０℃の範囲の温度において行われる。酸性触媒は、チタンテトラアルコキシドに対し、通常０．１〜１．０倍モル、好ましくは０．２〜０．７倍モルの範囲で用いられる。
【００３０】
本発明においては、前記チタンテトラアルコキシドの加水分解−縮合反応は、炭素数３以上のエーテル系酸素を有するアルコール類を所定量溶媒として使用することで、アルコキシル基のエステル交換が起こり比較的安定で経時変化の少ない加水分解縮合液が得られる。そして、当該チタンアルコキシド加水分解縮合物の縮合度を、前記加水分解縮合液の光散乱強度測定により制御する。例えば後述の本発明のコーティング剤の一成分として用いる場合、該加水分解縮合液の光散乱強度を、通常８，０００〜３００，０００ｃｐｓ、好ましくは９，０００〜２００，０００ｃｐｓの範囲に制御することが望ましい。
【００３１】
ここで、光散乱強度Ｉｓは（式１）で表され（Ｉｓ＝散乱光強度、Ｉｏ＝入射光強度、ｎ＝溶媒の屈折率、Ｍｗ＝溶質の重量平均分子量、ｃ＝溶質の濃度、（ｄｎ／ｄｃ）＝溶質の濃度増あたりの屈折率増分、λｏ＝入射光波長、ｒ＝試料から検出器までの距離、Ｎ_Ａ＝アボガドロ数）、Ｍｗに相当する分子サイズつまり、縮合度に比例した値が観測される。
【００３２】
【数１】

【００３３】
この光散乱強度（縮合度）は、水や触媒の使用量、溶媒の種類、加水分解温度や時間などによって調節することができる。
【００３４】
次に、本発明の傾斜膜形成用コーティング剤は、（Ａ）成分であるチタンテトラアルコキシドの加水分解縮合物を含む反応液と、（Ｂ）成分である主鎖または側鎖に、加水分解により前記チタンテトラアルコキシドの加水分解縮合物と結合し得るケイ素含有基（カップリング性ケイ素含有基）を有する有機高分子化合物を含む溶液とを混合してなり、かつ有機基材に塗布、乾燥した際に、実質上有機基材側が有機高分子化合物成分で、その反対側がチタン酸化物成分であって、両者の含有割合が膜厚方向に連続的に変化する成分傾斜構造を有する有機−無機複合傾斜膜を形成し得る塗布液からなるものである。
【００３５】
前記（Ａ）成分でチタンテトラアルコキシドの加水分解縮合物を含む反応液としては、前述の製造方法で説明したように、炭素数３以上のエーテル系酸素を有するアルコール類を溶媒として用い、酸性触媒の存在下に、加水分解−縮合反応させ、加水分解縮合液の光散乱強度を、通常８，０００〜３００，０００ｃｐｓ、好ましくは９，０００〜２００，０００ｃｐｓの範囲に制御したものが好ましく用いられる。
【００３６】
この（Ａ）成分における加水分解−縮合反応に、炭素数３以上のエーテル系酸素を有するアルコール類を溶媒として用いることにより、反応時のチタンアルコキシドの加水分解縮合物の大きさの制御、および（Ｂ）成分の有機高分子化合物を含む溶液と混合した時点で、チタンアルコキシド縮合物同士の反応による該縮合物の分子量増加よりも、カップリング性ケイ素含有基とチタンアルコキシドの加水分解縮合物との反応を選択的に進行させることができる。
【００３７】
一方、（Ｂ）成分における主鎖または側鎖に、カップリング性ケイ素含有基を有する有機高分子化合物は、例えば（ａ）金属を含まないエチレン性不飽和単量体と、（ｂ）カップリング性ケイ素含有基を有するエチレン性不飽和単量体とを共重合させることにより、得ることができる。
【００３８】
上記（Ｂ）（ａ）成分である金属を含まないエチレン性不飽和単量体としては、例えば一般式（Ｉ）
【００３９】
【化５】

【００４０】
（式中、Ｒ¹は水素原子またはメチル基、Ｘは一価の有機基である。）
で表されるエチレン性不飽和単量体、好ましくは一般式（Ｉ−ａ）
【００４１】
【化６】

【００４２】
（式中、Ｒ¹は水素原子またはメチル基、Ｒ²は一価の炭化水素基またはエポキシ基、ハロゲン原子若しくはエーテル結合を有する炭化水素基を示す。）
で表されるエチレン性不飽和単量体を一種または二種以上混合して仕様しても良い。
【００４３】
上記一般式（Ｉ−ａ）で表されるエチレン性不飽和単量体において、Ｒ²で示される炭化水素基としては、炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、炭素数３〜１０のシクロアルキル基、炭素数６〜１０のアリール基、炭素数７〜１０のアラルキル基を好ましく挙げることができる。炭素数１〜１０のアルキル基の例としては、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、および各種のブチル基、ペンチル基、ヘキシル基、オクチル基、デシル基などが挙げられる。炭素数３〜１０のシクロアルキル基の例としては、シクロペンチル基、シクロヘキシル基、メチルシクロヘキシル基、シクロオクチル基などが、炭素数６〜１０のアリール基の例としては、フェニル基、トリル基、キシリル基、ナフチル基、メチルナフチル基などが、炭素数７〜１０のアラルキル基の例としては、ベンジル基、メチルベンジル基、フェネチチル基、ナフチルメチル基などが挙げられる。エポキシ基、ハロゲン原子若しくはエーテル結合を有する炭化水素基としては、これらの基、原子若しくは結合を有する炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、炭素数３〜１０のシクロアルキル基、炭素数６〜１０のアリール基、炭素数７〜１０のアラルキル基を好ましく挙げることができる。上記置換基のハロゲン原子としては、塩素原子等が挙げられる。
【００４４】
この一般式（Ｉ−ａ）で表されるエチレン性不飽和単量体の例としては、メチル（メタ）アクリレート、エチル（メタ）アクリレート、プロピル（メタ）アクリレート、ブチル（メタ）アクリレート、ヘキシル（メタ）アクリレート、２−エチルヘキシル（メタ）アクリレート、シクロヘキシル（メタ）アクリレート、フェニル（メタ）アクリレート、ベンジル（メタ）アクリレート、グリシジル（メタ）アクリレート、３−グリシドキシプロピル（メタ）アクリレート、２−（３，４−エポキシシクロヘキシル）エチル（メタ）アクリレート、２−クロロエチル（メタ）アクリレート、２−ブロモエチル（メタ）アクリレートなどが挙げられる。これらは単独で用いてもよいし、２種以上を組み合わせて用いてもよい。
【００４５】
また、前記一般式（Ｉ）で表されるエチレン性不飽和単量体としては、これら以外にもスチレン、α−メチルスチレン、α−アセトキシスチレン、ｍ−、ｏ−またはｐ−ブロモスチレン、ｍ−、ｏ−またはｐ−クロロスチレン、ｍ−、ｏ−またはｐ−ビニルフェノール、１−または２−ビニルナフタレンなど、さらにはエチレン性不飽和基を有する重合性高分子用安定剤、例えばエチレン性不飽和基を有する、酸化防止剤、紫外線吸収剤および光安定剤なども用いることができる。これらは単独で用いてもよいし、２種以上を組み合わせて用いてもよい。
【００４６】
一方、（Ｂ）（ｂ）成分であるカップリング性ケイ素含有基を有するエチレン性不飽和単量体としては、例えば一般式（II）
【００４７】
【化７】

【００４８】
（式中、Ｒ³は水素原子またはメチル基、Ａは炭素数１〜４のアルキレン基、Ｒ⁴はメチル基又はエチル基を示す。）
で表される化合物を好ましく挙げることができる。前記一般式（II）において、３つのＲ⁴はたがいに同一でも異なっていてもよい。
【００４９】
この一般式（II）で表されるエチレン性不飽和単量体の例としては、２−（メタ）アクリロキシエチルトリメトキシシラン、２−（メタ）アクリロキシエチルトリエトキシシラン、γ−（メタ）アクリロキシプロピルトリメトキシシラン、γ−（メタ）アクリロキシプロピルトリエトキシシランなどが挙げられる。
この（ｂ）成分のカップリング性ケイ素含有基を有するエチレン性不飽和単量体は、１種を単独で用いてもよく、２種以上を組み合わせて用いてもよい。
【００５０】
前記（ａ）成分の金属を含まないエチレン性不飽和単量体と、（ｂ）成分のカップリング性ケイ素含有基を有するエチレン性不飽和単量体とを、ラジカル重合開始剤の存在下、ラジカル重合させることにより、（Ｂ）成分の成分として用いられるカップリング性ケイ素含有基を有する有機高分子化合物が得られる。
【００５１】
本発明においては、このようにして得られた（Ｂ）成分であるカップリング性ケイ素含有基を有する有機高分子化合物をアルコール、ケトン、エーテルなどの適当な溶剤中に溶解させた溶液と、前述の（Ａ）成分であるチタンアルコキシドの加水分解縮合物を含む反応液を必要により希釈した溶液とを混合することにより、前記有機高分子化合物中のカップリング性ケイ素含有基が加水分解し、（Ａ）成分の反応液におけるチタンアルコキシドの加水分解縮合物と選択的に反応し、有機−無機複合傾斜膜形成用のコーティング剤が得られる。なお、この際、用いるチタンアルコキシドの加水分解縮合物を含む反応液の希釈溶媒としては、前述した理由により炭素数３以上のエーテル系酸素を有するアルコール類を含む溶媒を使用することが望ましい。
【００５２】
本発明においては、良好な成分傾斜構造を有する複合傾斜膜を形成させるために、前記（Ａ）成分と（Ｂ）成分のケイ素含有基との反応、結合を、その反応液の光散乱強度の変化の測定により、制御する。
この場合、（Ａ）成分と、（Ｂ）成分とを混合してからの時間が重要となる。すなわち、（Ａ）成分と（Ｂ）成分とを混合すると、光散乱強度は経時により上昇するが、その上昇が実質上もはや起こらなくなったコーティング剤を使用することが肝要である。また、その際の光散乱強度が、混合直後の光散乱強度に対して、ある範囲の比率で高いことも重要である。
【００５３】
したがって、本発明のコーティング剤は、両成分を混合した直後からａ時間経過したものであって、前記（Ａ）成分と（Ｂ）成分とを混合した直後の光散乱強度をＸ_ｏ、混合直後からａ時間経過後の当該コーティング剤の光散乱強度をＸ_ａ、当該コーティング剤を温度２３℃でさらに１時間放置後の光散乱強度をＸ_ａ＋１とした場合、Ｘ_ａ／Ｘ_ｏ値が１．２〜１０、好ましくは１．５〜７の範囲であり、かつ（Ｘ_ａ＋１−Ｘ_ａ）／Ｘ_ａ値が０．０３以下、好ましくは０．０２以下であるコーティング剤が好適である。
【００５４】
Ｘ_ａ／Ｘ_ｏ値が１．２未満であると、（Ｂ）成分中のカップリング性ケイ素含有基成分の比率が少なく、（Ａ）成分と（Ｂ）成分の結合点が少なすぎるか、または（Ａ）成分分子が小さすぎるために良好な傾斜材料を得ることが困難であり、１０を超えると、（Ｂ）成分中のカップリング性ケイ素含有基成分の比率が多く、（Ａ）成分と（Ｂ）成分の結合点が多すぎるか、または（Ａ）成分分子の大きさが大きすぎるために均一材料になりやすく、良好な傾斜材料を得ることが困難であり、いずれも本発明の目的を達成しにくい。
また（Ｘ_ａ＋１−Ｘ_ａ）／Ｘ_ａ値が０．０３を超えると、（Ａ）成分と（Ｂ）成分の選択的反応が充分に進行しておらず、再現性が問題となり、本発明の目的を達成しにくい。
【００５５】
このような性状を有するコーティング剤を用いることにより、有機基材に塗布、乾燥した際に、実質上有機基材側が有機高分子化合物成分で、その反対側がチタン酸化物成分であって、両者の含有割合が膜厚方向に連続的に変化する良好な成分傾斜構造を有する有機−無機複合傾斜膜を、安定して形成することができる。
【００５６】
有機基材上に、複合傾斜膜を形成させるには、このようにして得られた本発明のコーティング剤を、乾燥塗膜の厚さが、通常５μｍ以下、好ましくは０．０１〜１．０μｍ、より好ましくは０．０２〜０．７μｍの範囲になるように、ディップコート法、スピンコート法、スプレーコート法、バーコート法、ナイフコート法、ロールコート法、ブレードコート法、ダイコート法、グラビアコート法などの公知の手段により塗布し、溶媒を揮散させて塗膜を形成させる。
【００５７】
上記有機基材としては、例えばポリメチルメタクリレートなどのアクリル樹脂、ポリスチレンやＡＢＳ樹脂などのスチレン系樹脂、ポリエチレンやポリプロピレンなどのオレフィン系樹脂、ポリエチレンテレフタレートやポリエチレンナフタレートなどのポリエステル系樹脂、６−ナイロンや６，６−ナイロンなどのポリアミド系樹脂、ポリ塩化ビニル系樹脂、ポリカーボネート系樹脂、ポリフェニレンサルファイド系樹脂、ポリフェニレンエーテル系樹脂、ポリイミド系樹脂、セルロースアセテートなどのセルロース系樹脂などからなる基材を挙げることができる。
【００５８】
これらの有機基材は、本発明に係る複合傾斜膜との密着性をさらに向上させるために、所望により、酸化法や凹凸化法などにより表面処理を施すことができる。上記酸化法としては、例えばコロナ放電処理、クロム酸処理（湿式）、火炎処理、熱風処理、オゾン・紫外線照射処理などが挙げられ、また、凹凸化法としては、例えばサンドブラスト法、溶剤処理法などが挙げられる。これらの表面処理法は基材の種類に応じて適宜選ばれる。
【００５９】
なお、本発明における有機基材は、有機系材料以外の材料、例えば金属系材料、ガラスやセラミックス系材料、その他各種無機系または金属系材料からなる基材の表面に、有機系塗膜を有するものも包含する。
また、塗膜の傾斜構造の確認は、例えば塗膜表面にスパッタリングを施して膜を削っていき、経時的に膜表面の炭素原子とチタン原子の含有率を、Ｘ線光電子分光法などにより測定することによって、行うことができる。
【００６０】
この複合傾斜膜における金属成分の含有量としては特に制限はないが、金属酸化物換算で、通常５〜９８重量％、好ましくは２０〜９８重量％、特に好ましくは５０〜９５重量％の範囲である。有機高分子化合物の重合度や分子量としては、製膜化しうるものであればよく特に制限されず、高分子化合物の種類や所望の傾斜膜材料の物性などに応じて適宜選定すればよい。
【００６１】
本発明のコーティング剤を用いて形成された有機−無機複合傾斜膜は、機能性膜として様々な用途に用いることができるが、特に有機基材と光触媒活性材料層との間に介在させる中間膜として好適に用いられる。
本発明はまた、有機材料上に、前記コーティング剤を用いて形成された有機−無機複合傾斜膜を有し、かつ該膜の表面が実質上チタン酸化物成分である構造体をも提供する。
このような構造体としては、有機−無機複合傾斜膜上に、光触媒活性材料層を設けた防汚性を有する構造体を好ましく挙げることができる。
【００６２】
前記光触媒活性材料としては特に制限はなく、従来公知のもの、例えば二酸化チタン、チタン酸ストロンチウム（ＳｒＴｉＯ_３）、チタン酸バリウム（ＢａＴｉ_４Ｏ_９）、チタン酸ナトリウム（Ｎａ_２Ｔｉ_６Ｏ_１３）、二酸化ジルコニウム、α−Ｆｅ_２Ｏ_３、酸化タングステン、Ｋ_４Ｎｂ_６Ｏ_１７、Ｒｂ_４Ｎｂ_６Ｏ_１７、Ｋ_２Ｒｂ_２Ｎｂ_６Ｏ_１７、硫化カドミウム、硫化亜鉛などを挙げることができる。これらは１種を単独で用いてもよいし、２種以上を組み合わせて用いてもよいが、これらの中で、二酸化チタン、特にアナターゼ型二酸化チタンは実用的な光触媒活性材料として有用である。この二酸化チタンは、太陽光などの日常光に含まれる紫外線領域の特定波長の光を吸収することによって優れた光触媒活性を示す。
【００６３】
本発明における光触媒活性材料層には、光触媒活性を促進させる目的で、上記光触媒活性材料と共に、所望により従来公知の光触媒促進剤を含有させることができる。この光触媒促進剤としては、例えば白金、パラジウム、ロジウム、ルテニウムなどの白金族金属が好ましく挙げられる。これらは単独で用いてもよいし、２種以上を組み合わせて用いてもよい。この光触媒促進剤の添加量は、光触媒活性の点から、通常、光触媒活性材料と光触媒促進剤との合計重量に基づき、１〜２０重量％の範囲で選ばれる。
【００６４】
有機−無機複合傾斜膜上に光触媒活性材料層を形成させる方法としては特に制限はなく、様々な方法を用いることができるが、例えば真空蒸着法、スパッタリング法などのＰＶＤ法（物理気相蒸着法）や金属溶射法などの乾式法、塗工液を用いる湿式法などを好ましく挙げることができる。
【００６５】
一方、塗工液を用いる方法においては、適当な溶媒中に、光触媒活性材料および必要に応じて用いられる光触媒促進剤や無機系バインダーなどの微粒子を含む分散液からなる塗工液を調製し、この塗工液を複合傾斜膜上に、公知の方法、例えばディップコート法、スピンコート法、スプレーコート法、バーコート法、ナイフコート法、ロールコート法、ブレードコート法、ダイコート法、グラビアコート法などにより塗布し、自然乾燥または加熱乾燥することにより、光触媒活性材料層を形成させる方法などを用いることができる。また、光触媒促進剤を用いる場合、例えば光触媒活性材料および所望により用いられる無機系バインダーなどの微粒子を含む塗工液を複合傾斜膜上に塗布し、光触媒活性材料の塗膜を形成させたのち、溶存酸素が除去された光触媒促進剤の金属イオンを含む水溶液に、前記の複合傾斜膜上に光触媒活性材料の塗膜が形成された構造体を浸漬し、光を照射して、該金属イオンを塗膜面に沈積させる光デポジション法により、光触媒活性材料の塗膜上に光触媒促進剤層を設けることによって、光触媒活性材料層を形成させることもできる。
【００６６】
前記塗工液の調製において必要により用いられる無機系バインダーとしては、バインダーとしての機能を発揮し得るものであればよく、特に制限されず、従来公知のもの、例えばケイ素、アルミニウム、チタニウム、ジルコニウム、マグネシウム、ニオビウム、タングステン、スズ、タンタルなどの金属の酸化物や水酸化物、あるいは上記金属の中から選ばれた２種以上の金属の複合酸化物や複合水酸化物などを挙げることができる。この無機系バインダーは１種用いてもよいし、２種以上を組み合わせて用いてもよい。また、該塗工液には、光触媒活性材料層形成用の塗工液に使用される従来公知の他の添加成分、例えばシリコーン樹脂や変性シリコーン樹脂、シランカップリング剤などを含有させることができる。
【００６７】
本発明においては、光触媒活性材料層の厚みは、通常１０ｎｍ〜５μｍの範囲で選定される。この厚みが１０ｎｍ未満では光触媒機能が十分に発揮されないし、５μｍを超えると厚みの割には光触媒機能の向上効果が認められず、むしろクラックが生じたり、構造体がフィルムやシートの場合、屈曲性が低下する原因となる。好ましい厚みは３０ｎｍ〜３μｍであり、特に４０ｎｍ〜１μｍの範囲が好ましい。
【００６８】
本発明の構造体においては、有機材料に有機−無機複合傾斜膜を介して、好ましくは光触媒活性材料層が設けられており、そして、該複合傾斜膜が、実質上、光触媒活性材料層との界面ではチタン酸化物成分のみからなり、かつ有機材料に当接している面では有機高分子化合物成分のみからなるため、有機材料と複合傾斜膜との密着性および光触媒活性材料層と複合傾斜膜との密着性が極めて良好である。また、光触媒活性材料層との界面において、複合傾斜膜が実質上チタン酸化物系化合物成分のみであるため、光触媒活性材料層の光触媒機能による複合傾斜膜の劣化が抑制される。
このような光触媒活性材料層が設けられた本発明の構造体は、防汚、抗菌、脱臭機能を有し、これらの機能が要求される様々な用途に用いられる。
【００６９】
【実施例】
次に、本発明を、実施例によりさらに詳細に説明するが、本発明は、これらの例によってなんら限定されるものではない。
【００７０】
なお、各例における諸特性は、以下に示す方法により求めた。
（１）光散乱強度の測定
測定対象液をガラスセルに入れて、大塚電子（株）製の「ＥＬＳ−８０００」により、光散乱強度測定を行った。１００回測定を行い、その平均値を求めた。この際、ピンホールの大きさは、サンプル側を径０．３ｍｍ、検出側を径０．２ｍｍとして測定を行った。
【００７１】
（２）光触媒耐久性（促進耐候試験）
ＪＩＳ Ｋ７３５０に準じたカーボンアーク式サンシャインウエザーメーター試験法［試験機：スガ試験機（株）製のサンシャインウエザーメーター「Ｓ３００」］により、促進耐候試験（光源：２５５Ｗ／ｍ²、サイクル：照射１０２分間、照射＋降雨１８分間の２時間１サイクル、ブラックパネル温度：６３±３℃、相対湿度：５５±５％）を９００時間行い、日本電色（株）製、ヘイズメーター「ＮＤＨ２０００」を用い、ＪＩＳ Ｋ７３６１に準拠してヘイズ値を測定した。
【００７２】
（３）溶液の粘度測定
山内電機社製振動式粘度計「ＶＭ−１−Ｇ−Ｌ」にて、３０℃恒温状態で測定を行った。
【００７３】
（４）成分傾斜膜の傾斜性
ＸＰＳ装置「ＰＨＩ−５６００」［アルバックファイ（株）製］を用い、アルゴンスパッタリング（４ｋＶ）を３分間隔で施して膜を削り、膜表面の炭素原子とチタン原子の含有率を、Ｘ線光電子分光法により測定し、傾斜性を調べた。
調製例 高分子化合物溶液の調製
メチルメタクリレート１０．９ｇおよびγ−メタクリロキシプロピルトリメトキシシラン１．３６ｇの混合溶液に、２，２′ーアゾビスイソブチロニトリル０．１ｇを溶解させた後、攪拌しながら７５℃で３時間反応させて、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）法によるポリスチレン換算の重量平均分子量が約７万の共重合体を得た。この共重合体１．０ｇをメチルイソブチルケトン１００ｍｌに溶解させ、１０ｇ／Ｌ濃度の高分子化合物を得た。
【００７４】
実施例１
チタンテトライソプロポキシド１２．５ｍｌ（０．０４２ｍｏｌ）をエチレングリコールモノエチルエーテル（エチルセロソルブ）１６．８ｍｌ（０．１７４ｍｏｌ）に溶解した溶液に、濃硝酸１．６３ｍｌ（０．０２１ｍｏｌ）、水０．８２ｍｌ（０．０４６ｍｏｌ）とエチルセロソルブ１６．８ｍｌ（０．１７４ｍｏｌ）の混合溶液を攪拌しながらゆっくり滴下し、その後３０℃で攪拌しながら、任意の時間毎に光散乱強度の測定を行い、チタン加水分解−縮合物の縮合度（分子量）の増加を評価した。反応時間と光散乱強度および溶液粘度との関係を表１に示す。
【００７５】
【表１】

【００７６】
反応時間の経過、溶液粘度の上昇と光散乱強度の増加に相関性が見られた。
【００７７】
実施例２〜５
実施例１において、反応時の水および濃硝酸の添加量を変えた以外は、実施例１と同様にしてチタンテトライソプロポキシドの加水分解−縮合反応を行った。４時間反応後の光散乱強度の測定結果を表２に示す。
【００７８】
【表２】

【００７９】
反応条件（一般にチタンアルコキシドの加水分解−縮合は水の添加量が多いほどまた、触媒の添加量が少ないほど進行し易い。）に応じて溶液粘度が上昇し、今回測定した光散乱強度が相関していることが確認された。
【００８０】
実施例６
実施例３で得られたチタン加水分解−縮合物溶液８．３ｍｌにエチルセロソルブ１６．７ｍｌ、メチルイソブチルケトン２０ｍｌ、次いで調製例で得た高分子化合物溶液５ｍｌを加えて混合液を作製した。この溶液を混合後から任意の時間毎に光散乱強度の測定を行い両成分の反応状態の評価を行った。表３に、混合経過時間と光散乱強度との関係を示す。混合後の経過時間に応じて光散乱強度が上昇し、チタン加水分解物と有機高分子化合物の反応が進行したことが確認できた。
【００８１】
比較例１
調製例において、γ−メタクリロキシプロピルトリメトキシシランを用いることなしに得られた高分子化合物溶液を用いた以外は、実施例６と同様に実施した。表３に、混合経過時間と光散乱強度との関係を示す。
【００８２】
【表３】

【００８３】
実施例７
チタンテトライソプロポキシド１２．５ｍｌ（０．０４２ｍｏｌ）をエチレングリコールモノエチルエーテル（エチルセロソルブ）１６．８ｍｌ（０．１７４ｍｏｌ）に溶解した溶液に、濃硝酸１．６３ｍｌ（０．０２１ｍｏｌ）、水０．８２ｍｌ（０．０４６ｍｏｌ）とエチルセロソルブ１６．８ｍｌ（０．１７４ｍｏｌ）の混合溶液を攪拌しながらゆっくり滴下し、その後３０℃で４時間攪拌して加水分解−縮合反応を行い、反応液を得た。この反応液の光散乱強度を測定したところ、１２，０００ｃｐｓであった。
【００８４】
次に、反応液８．３ｍｌに、エチルセロソルブ１６．７ｍｌ、メチルイソブチルケトン２０ｍｌ、次いで調製例で得た高分子化合物溶液５ｍｌを加えて混合液を作製した。その直後の光散乱強度を測定したところ、５，０００ｃｐｓであった。次いで、これを、室温下（２３℃）で約２０時間攪拌を行い、チタンテトライソプロポキシドの加水分解縮合物と高分子化合物のカップリング性ケイ素含有基部位との選択的反応を行った後に光散乱強度の測定を行ったところ、９，８００ｃｐｓであった。この液の一部を採り、２３℃で、さらに１時間攪拌し、光散乱強度を測定したところ、９，８７０ｃｐｓであった。したがって、Ｘ_ａ／Ｘ_ｏ値は１．９６であり、（Ｘ_ａ＋１−Ｘ_ａ）／Ｘ_ａ値は０．０１であった。
【００８５】
前記の２０時間攪拌して得られたコーティング液を、ワイヤー線径０．０７５ｍｍのマイヤーバーにて、厚さ５０μｍのポリエチレンテレフタレート（ＰＥＴ）フィルム［帝人デュポンフィルム（株）製「テトロンＨＢ−３」］上にバーコートし、溶剤を揮発させて、厚さ７０ｎｍの複合傾斜膜を形成させた。この傾斜膜のＸＰＳ測定結果を図１に示す。この図より、傾斜性を有する膜であることが確認された。
【００８６】
次に、該膜上に、石原産業（株）製の光触媒液「ＳＴ−Ｋ２１１」を塗布し、厚さ５０ｎｍの光触媒膜を設けた。この光触媒膜付フィルムについて、促進耐候試験を行ったところ、９００時間経過後のヘイズ値は３．７８％で、透明性を維持していた。
【００８７】
実施例８
メチルイソブチルケトンを１０ｍｌ、及び調製例で得た高分子化合物溶液を１０ｍｌ使用した以外は実施例７と同様にして塗膜用混合液を調製した。その直後の光散乱強度を測定したところ、６，０００ｃｐｓであった。次いで、これを、室温下（２３℃）で約２０時間攪拌を行い、チタンテトライソプロポキシドの加水分解縮合物と高分子化合物のカップリング性ケイ素含有基部位との選択的反応を行った後に光散乱強度の測定を行ったところ、１４，８００ｃｐｓであった。この液の一部を採り、２３℃で、さらに１時間攪拌し、光散乱強度を測定したところ、１５，０００ｃｐｓであった。したがって、Ｘ_ａ／Ｘ_ｏ値は２．４６であり、（Ｘ_ａ＋１−Ｘ_ａ）／Ｘ_ａ値は０．０１であった。
【００８８】
前記の２０時間攪拌して得られたコーティング液を用い、実施例７と同様にしてＰＥＴフィルム上に厚さ７５ｎｍの複合傾斜膜を形成させた。
次に、該膜上に、実施例７と同様にして、厚さ５０ｎｍの光触媒膜を設けた。この光触媒膜付フィルムについて、促進耐候試験を行ったところ、９００時間経過後のヘイズ値は３．５％で、透明性を維持していた。
【００８９】
実施例９
メチルイソブチルケトンを５ｍｌ、及び調製例で得た高分子化合物溶液を１５ｍｌ使用した以外は実施例７と同様にして塗膜用混合液を調製した。その直後の光散乱強度を測定したところ、５，７００ｃｐｓであった。次いで、これを、室温下（２３℃）で約２０時間攪拌を行い、チタンテトライソプロポキシドの加水分解縮合物と高分子化合物のカップリング性ケイ素含有基部位との選択的反応を行った後に光散乱強度の測定を行ったところ、１９，３００ｃｐｓであった。この液の一部を採り、２３℃で、さらに１時間攪拌し、光散乱強度を測定したところ、１９，４００ｃｐｓであった。したがって、Ｘ_ａ／Ｘ_ｏ値は３．３９であり、（Ｘ_ａ＋１−Ｘ_ａ）／Ｘ_ａ値は０．０１であった。
【００９０】
前記の２０時間攪拌して得られたコーティング液を用い、実施例７と同様にしてＰＥＴフィルム上に厚さ８０ｎｍの複合傾斜膜を形成させた。
次に、該膜上に、実施例７と同様にして、厚さ５０ｎｍの光触媒膜を設けた。この光触媒膜付フィルムについて、促進耐候試験を行ったところ、９００時間経過後のヘイズ値は４．０％で、透明性を維持していた。
【００９１】
実施例１０
実施例７において、水の量を１．２３ｍｌ（０．０６９モル）に変更した以外は、実施例７と同様にしてチタンテトライソプロポキシドの加水分解−縮合反応を行った。この反応液の光散乱強度を測定したところ、２５０，０００ｃｐｓであった。
【００９２】
次に、この反応液８．３ｍｌに、エチルセロソルブ１６．７ｍｌ、メチルイソブチルケトン２０ｍｌ、次いで調製例で得た高分子化合物溶液５ｍｌを加えて混合液を作製した。その直後の光散乱強度を測定したところ、１００，０００ｃｐｓであった。次いで、これを、室温下（２３℃）で約２０時間攪拌を行い、チタンテトライソプロポキシドの加水分解縮合物と高分子化合物のカップリング性ケイ素含有基部位との選択的反応を行った後に光散乱強度の測定を行ったところ、２１０，０００ｃｐｓであった。この液の一部を採り、２３℃で、さらに１時間攪拌し、光散乱強度を測定したところ、２１１，５００ｃｐｓであった。したがって、Ｘ_ａ／Ｘ_ｏ値は２．１０であり、（Ｘ_ａ＋１−Ｘ_ａ）／Ｘ_ａ値は０．０１であった。
【００９３】
前記の２０時間攪拌して得られたコーティング液を用い、実施例７と同様にしてＰＥＴフィルム上に厚さ７０ｎｍの複合傾斜膜を形成させた。この傾斜膜のＸＰＳ測定結果を図２に示す。この図より、傾斜性を有する膜であることが確認された。
【００９４】
次に、該膜上に、実施例７と同様にして、厚さ５０ｎｍの光触媒膜を設けた。この光触媒膜付フィルムについて、促進耐候試験を行ったところ、９００時間経過後のヘイズ値は４．５％で、透明性を維持していた。
【００９５】
実施例１１
実施例７において、溶媒としてエチレングリコールモノメチルエーテル（メチルセロソルブ）を用いた以外は、実施例７と同様にしてチタンテトライソプロポキシドの加水分解−縮合反応を行った。この反応液の光散乱強度を測定したところ、９，０００ｃｐｓであった。
【００９６】
次に、この反応液８．３ｍｌに、メチルセロソルブ１６．７ｍｌ、メチルイソブチルケトン２０ｍｌ、次いで調製例で得た高分子化合物溶液５ｍｌを加えて混合液を作製した。その直後の光散乱強度を測定したところ、３，５００ｃｐｓであった。次いで、これを、室温下（２３℃）で約２０時間攪拌を行い、チタンテトライソプロポキシドの加水分解縮合物と高分子化合物のカップリング性ケイ素含有基部位との選択的反応を行った後に光散乱強度を測定したところ、７，０００ｃｐｓであった。この液の一部を採り、２３℃で、１時間さらに攪拌し、光散乱強度を測定したところ、７，１５０ｃｐｓであった。したがって、Ｘ_ａ／Ｘ_ｏ値は２．００であり、（Ｘ_ａ＋１−Ｘ_ａ）／Ｘ_ａ値は０．０２であった。
【００９７】
前記の２０時間攪拌して得られたコーティング液を用い、実施例７と同様にしてＰＥＴフィルム上に厚さ７０ｎｍの複合傾斜膜を形成させた。この傾斜膜のＸＰＳ測定結果を図３に示す。この図より、傾斜性を有する膜であることが確認された。
【００９８】
次に、該膜上に、実施例７と同様にして、厚さ５０ｎｍの光触媒膜を設けた。この光触媒膜付フィルムについて、促進耐候試験を行ったところ、９００時間経過後のヘイズ値は２．９％で、透明性を維持していた。
【００９９】
比較例２
実施例７において、水の量を１．６４ｍｌ（０．０９２モル）に変更した以外は、実施例７と同様にしてチタンテトライソプロポキシドの加水分解−縮合反応を行った。この反応液の光散乱強度を測定したところ、３５０，０００ｃｐｓであった。
【０１００】
次に、この反応液８．３ｍｌに、エチルセロソルブ１６．７ｍｌ、メチルイソブチルケトン２０ｍｌ、次いで調製例で得た高分子化合物溶液５ｍｌを加えて混合液を作製した。その直後の光散乱強度を測定したところ、１５０，０００ｃｐｓであった。次いで、これを、室温下（２３℃）で約２０時間攪拌を行い、チタンテトライソプロポキシドの加水分解縮合物と高分子化合物のカップリング性ケイ素含有基部位との選択的反応を行った後に光散乱強度の測定を行ったところ、１７０，０００ｃｐｓであった。この液の一部を採り、２３℃で、１時間さらに攪拌し、光散乱強度を測定したところ、１７４，９００ｃｐｓであった。したがって、Ｘ_ａ／Ｘ_ｏ値は１．１３であり、（Ｘ_ａ＋１−Ｘ_ａ）／Ｘ_ａ値は０．０３であった。
【０１０１】
前記の２０時間攪拌して得られたコーティング液を用い、実施例７と同様にしてＰＥＴフィルム上に厚さ７０ｎｍの複合膜を形成させた。この複合膜のＸＰＳ測定結果を図４に示す。この図より、（Ａ）成分及び（Ｂ）成分がほぼ均一であることが確認された。
【０１０２】
次に、該膜上に、実施例７と同様にして、厚さ５０ｎｍの光触媒膜を設けた。この光触媒膜付フィルムについて、促進耐候試験を行ったところ、９００時間経過後のヘイズ値は１０％で白濁していた。
【０１０３】
比較例３
実施例７において、溶媒としてイソプロピルアルコールを用いた以外は、実施例７と同様にしてチタンテトライソプロポキシドの加水分解−縮合反応を行った。この反応液の光散乱強度を測定したところ、２０，０００ｃｐｓであった。
【０１０４】
次に、この反応液８．３ｍｌに、イソプロピルアルコール１６．７ｍｌ、メチルイソブチルケトン２０ｍｌ、次いで調製例で得た高分子化合物溶液５ｍｌを加えて混合液を作製した。その直後の光散乱強度を測定したところ、１０，０００ｃｐｓであった。次いで、これを、室温下（２３℃）で約２０時間攪拌を行い、チタンテトライソプロポキシドの加水分解縮合物と高分子化合物のカップリング性ケイ素含有基部位との選択的反応を行った後に光散乱強度の測定を行ったところ、１１０，０００ｃｐｓであった。この液の一部を採り、２３℃で、さらに１時間攪拌して、光散乱強度を測定したところ、１１９，０００ｃｐｓであった。したがって、Ｘ_ａ／Ｘ_ｏ値は１１．０であり、（Ｘ_ａ＋１−Ｘ_ａ）／Ｘ_ａ値は０．０８であった。
【０１０５】
前記の２０時間攪拌して得られたコーティング液を用い、実施例７と同様にしてＰＥＴフィルム上に厚さ７０ｎｍの複合膜を形成させた。この複合膜のＸＰＳ測定結果を図５に示す。この図より、（Ａ）成分及び（Ｂ）成分がほぼ均一であることが確認された。
【０１０６】
次に、該膜上に、実施例７と同様にして、厚さ５０ｎｍの光触媒膜を設けた。この光触媒膜付フィルムについて、促進耐候試験を行ったところ、９００時間経過後のヘイズ値は１５％で白濁していた。
【０１０７】
【発明の効果】
本発明によれば、チタンアルコキシド加水分解縮合物を製造するに際し、その縮合度を効率よく制御する方法、および有機基材に塗布、乾燥した際に、実質上有機基材側が有機高分子化合物成分で、その反対側がチタン酸化物成分であって、両者の含有割合が膜厚方向に連続的に変化する良好な成分傾斜構造を有する有機−無機複合傾斜膜を、安定して形成し得る傾斜膜形成用コーティング剤を提供することができる。
【０１０８】
また、このコーティング剤を用いて、有機材料上に傾斜膜を形成し、さらにその上に光触媒層を設けることにより、防汚性を有し、かつ耐久性に優れる構造体を得ることができる。
【図面の簡単な説明】
【図１】実施例７で形成された複合膜におけるスパッタリング時間と炭素原子およびチタン原子の含有率との関係を示すグラフである。
【図２】実施例１０で形成された複合膜におけるスパッタリング時間と炭素原子およびチタン原子の含有率との関係を示すグラフである。
【図３】実施例１１で形成された複合膜におけるスパッタリング時間と炭素原子およびチタン原子の含有率との関係を示すグラフである。
【図４】比較例２で形成された複合膜におけるスパッタリング時間と炭素原子およびチタン原子の含有率との関係を示すグラフである。
【図５】比較例３で形成された複合膜におけるスパッタリング時間と炭素原子およびチタン原子の含有率との関係を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a titanium alkoxide hydrolysis condensate, a coating agent for forming a gradient film, and a structure having a gradient film. More specifically, the present invention relates to a method for efficiently controlling the degree of condensation when producing a titanium alkoxide hydrolyzed condensate, and when the organic base material is applied to an organic base material and dried, the organic base material side is substantially an organic polymer. An organic-inorganic composite gradient film having a favorable component gradient structure in which the opposite side of the compound component is a titanium oxide component and the content ratio of both components continuously changes in the film thickness direction can be stably formed. The present invention relates to a gradient film forming coating agent and a structure having a gradient film formed using the coating agent.
[0002]
[Prior art]
Conventionally, a layer made of various inorganic or metal materials such as photocatalytic active materials, conductive materials, hard coat agents, optical recording materials, magnetic powders, infrared absorbing materials, etc. is provided on an organic base material, and functional materials are provided. It is widely made.
[0003]
When such an inorganic or metal material layer is provided on an organic base material, in general, since an adhesive property with the base material is insufficient, for example, an inorganic primer layer is provided on the organic base material. A method of forming an inorganic or metal material layer on the substrate is often used. However, in this method, the adhesion between the inorganic primer layer and the inorganic or metal material layer is good, but the adhesion between the organic substrate and the inorganic primer layer is not always sufficient, and the heat resistant adhesion There is a problem that the adhesiveness is inferior or the adhesiveness decreases with time.
[0004]
In addition, a method is disclosed in which the adhesiveness to an inorganic substance is gradually improved via a plurality of adhesive layers on an organic substrate (see, for example, Patent Document 1). However, in this method, the operation is complicated and transparency may be impaired.
Therefore, development of a technique for forming an inorganic or metal material layer on an organic substrate with good adhesion has been desired.
[0005]
Under such circumstances, the present inventors previously described various applications as novel functional materials, such as coating films, adhesives between organic materials and inorganic or metal materials, organic substrates and photocatalysts. Thickness that is provided between the coating and useful for applications such as an intermediate film that prevents deterioration of the organic base material and an intermediate film that improves the adhesion between the organic base material and the inorganic or metal material layer. An organic-inorganic composite gradient material whose composition continuously changes in the direction has been found (for example, see Patent Document 2).
[0006]
This organic-inorganic composite gradient material is an organic-inorganic composite material containing a chemical bond between an organic polymer compound and a metal compound, and the content of the metal compound is continuously in the thickness direction of the material. It is a novel material that has a changing component gradient structure and is extremely useful for the various applications described above.
[0007]
The organic-inorganic composite gradient material is obtained by hydrolyzing a mixture of an organic polymer compound having a metal-containing group capable of binding to a metal oxide by hydrolysis and a metal compound capable of forming a metal oxide by hydrolysis. It is formed by applying a coating agent containing a decomposition treatment product on an organic substrate and subjecting it to a heat drying treatment. And in such a gradient material, since it forms using the adsorption | suction ability with respect to the base material of a polymer part, in order to obtain the material which is excellent in gradient, the time from preparation of a coating agent to application | coating, coating agent It is important to optimize the properties and the like.
[0008]
By the way, as an example of the formation of the organic-inorganic composite gradient film having the component gradient structure, the following method can be used. First, a reaction solution containing a hydrolysis condensate of titanium alkoxide and a silicon-containing group that can be bonded to the hydrolysis condensate by hydrolysis in the molecule (hereinafter sometimes referred to as a coupling silicon-containing group). A coating agent is prepared by mixing with a solution containing an organic polymer compound having. Next, by applying and drying the coating agent on the organic base material, a composite gradient film in which the organic base material side is substantially an organic polymer compound component and the opposite side is a titanium oxide component can be formed.
[0009]
In this case, in the expression of the inclined structure, the adsorption of the organic polymer compound to the organic base material becomes a driving force. Therefore, in order to develop a better gradient structure and exhibit high durability as an intermediate film of a photocatalytically active material layer (hereinafter sometimes abbreviated as a photocatalytic layer), for example, coupling properties in organic polymer compounds It is a very important factor that the silicon-containing group and the hydrolysis condensate of titanium alkoxide have a bond and that the size of the hydrolysis condensate of titanium alkoxide is adjusted to a certain range.
[0010]
That is, when the organic polymer compound is adsorbed on the organic substrate, the hydrolysis condensate of titanium alkoxide reacted with the coupling silicon-containing group site in the organic polymer compound is taken into the organic polymer compound layer. The source of the inclined structure. It is also important to adjust the size of the hydrolysis condensate of titanium alkoxide. If the condensate is too large, adsorption of the organic polymer compound to the base material is hindered, resulting in a film having a uniform composition and small. In some cases, the inclined structure does not appear and a layer separation membrane is obtained.
[0011]
[Patent Document 1]
WO97 / 00134 Publication
[Patent Document 2]
JP 2000-336281 A
[0012]
[Problems to be solved by the invention]
Under such circumstances, the present invention provides a method for efficiently controlling the degree of condensation when producing a titanium alkoxide hydrolyzed condensate, and a substantially organic group when applied to an organic substrate and dried. Stable organic-inorganic composite gradient film with a good component gradient structure where the material side is an organic polymer compound component and the opposite side is a titanium oxide component, and the content ratio of both is continuously changing in the film thickness direction An object of the present invention is to provide a coating agent for forming a gradient film that can be formed as described above, and a structure having a gradient film formed using the coating agent.
[0013]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have obtained the following knowledge. Titanium alkoxide and its decomposition products are generally known to be extremely reactive. Therefore, when using an alcohol solvent such as methanol, ethanol, isopropanol or the like that is usually used as a hydrolysis condensation solvent for titanium alkoxide, the reaction control is difficult and white precipitation occurs or gelation is likely to occur. In some cases, the hydrolysis-condensation liquid cannot be used as a coating agent component.
[0014]
Under these circumstances, the inventors have
(1) It is advantageous to use alcohols having an ether oxygen having 3 or more carbon atoms as the hydrolysis condensation solvent for titanium alkoxide, and the condensation degree of the hydrolysis condensate can be easily determined by measuring light scattering intensity. Can be controlled,
(2) When preparing a coating agent by mixing a reaction solution containing a hydrolysis condensate of titanium tetraalkoxide and a solution containing an organic polymer compound having a coupling silicon-containing group, when using a diluting solvent For the same reason as (2) above, it is advantageous to use an alcohol having an etheric oxygen having 3 or more carbon atoms as the diluting solvent,
[0015]
(3) When the coating agent is used, the selective reaction between the coupling silicon-containing group site in the organic polymer compound and the hydrolyzed condensate of titanium alkoxide having a controlled molecular weight is substantially completed. The state is important for developing a good gradient structure, and the state in which this reaction is substantially completed is due to the change over time in the light scattering intensity immediately after mixing the solutions containing the respective components. Can confirm,
I found. The present invention has been completed based on such findings.
[0016]
That is, the present invention
(1) In producing a titanium alkoxide hydrolysis condensate by subjecting titanium tetraalkoxide to a hydrolysis-condensation reaction in an organic solvent, the degree of condensation of the resulting hydrolysis condensate is determined as a reaction solution containing the hydrolysis condensate. A method for producing a titanium alkoxide hydrolyzed condensate, characterized in that it is controlled by measuring the light scattering intensity of
(2) The method according to (1) above, wherein the organic solvent is a solvent containing an alcohol having an etheric oxygen having 3 or more carbon atoms,
[0017]
(3)A method for producing an organic-inorganic composite gradient film having a component gradient structure,
  (A) a reaction solution containing a hydrolysis condensate of titanium tetraalkoxide, and (B) an organic compound having a silicon-containing group capable of binding to the hydrolysis condensate of titanium tetraalkoxide by hydrolysis in the main chain or side chain. Coating agent prepared by mixing a solution containing a polymer compoundIs applied to an organic substrate.,
  Reaction and bond between hydrolysis condensate in component (A) and silicon-containing group of organic polymer compound in component (B)TheControlled by measuring changes in light scattering intensity of the reaction solutionHowever, the reaction and the coupling are performed,
  An organic-inorganic composite gradient film having a component gradient structure in which the organic base material side is substantially an organic polymer compound component and the opposite side is a titanium oxide component, and the content ratio of both is continuously changed in the film thickness direction.A method for producing an organic-inorganic composite graded film characterized in that,
[0018]
(4) When mixing (A) component and (B) component or after mixing, a solvent containing an alcohol having an etheric oxygen having 3 or more carbon atoms is added as a diluting solvent.Method,
(5) The organic polymer compound used for the component (B) is (a) the general formula (Ia)
[0019]
[Chemical 3]

[0020]
(Wherein R¹Is a hydrogen atom or a methyl group, R²Represents a monovalent hydrocarbon group. )
An ethylenically unsaturated monomer represented by formula (b):
[0021]
[Formula 4]

[0022]
(Wherein R^ThreeIs a hydrogen atom or a methyl group, A is an alkylene group having 1 to 4 carbon atoms, R^FourRepresents a methyl group or an ethyl group. )
The above (3) or (4) is a copolymer with an ethylenically unsaturated monomer represented byMethod,
[0023]
(6) The light scattering intensity of the component (A) is 8,000 to 300,000 cps, as described in the above item (3), (4) or (5)Method,
(7) The organic material according to any one of (3) to (6) aboveMethodUsingHaveMachine-inorganic composite gradient filmFormationAnd the surface of the membraneTheSubstantially titanium oxide componentConfigure withStructure characterized by thatManufacturing method,
(8) A photocatalytic active material layer is provided on the organic-inorganic composite gradient film.AboveDescribed in paragraph (7)Method,
Is to provide.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
In the method for producing a titanium alkoxide hydrolysis condensate of the present invention, a titanium tetraalkoxide is subjected to a hydrolysis-condensation reaction in an organic solvent, usually in the presence of an acidic catalyst, to produce a titanium alkoxide hydrolysis condensate.
[0025]
As the titanium tetraalkoxide, titanium tetraalkoxide having 1 to 4 carbon atoms in the alkoxyl group is used. In this titanium tetraalkoxide, the four alkoxyl groups may be the same or different, but the same one is preferably used from the viewpoint of availability. Examples of the titanium tetraalkoxide include titanium tetramethoxide, titanium tetraethoxide, titanium tetra-n-propoxide, titanium tetraisopropoxide, titanium tetra-n-butoxide, titanium tetraisobutoxide, titanium tetra-sec- Examples include butoxide and titanium tetra-tert-butoxide. These may be used individually by 1 type and may be used in combination of 2 or more type.
[0026]
On the other hand, as the organic solvent, alcohols having ether-based oxygen having 3 or more carbon atoms are preferable from the viewpoint of controlling the hydrolysis-condensation reaction and stabilizing the condensate. Examples of the alcohol having an etheric oxygen having 3 or more carbon atoms include solvents having an interaction with titanium tetraalkoxide, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether. Cellosolve solvents such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether it can. Of these, cellosolve solvents are preferred in view of the drying rate after coating when the titanium alkoxide condensate is used as a coating agent. These solvent may be used individually by 1 type, and may be used in combination of 2 or more type.
[0027]
By using such alcohols having an ether oxygen having 3 or more carbon atoms as a solvent, the titanium alkoxide interacts with the solvent and is stabilized. In general, a compound having a β-diketone structure may be used to stabilize titanium alkoxide. However, since this compound has a high boiling point, if it is contained as a coating agent component, it is difficult to volatilize and stabilizes. Is too high and tends to remain in the film. In contrast, the alcohols used in the present invention have a relatively low boiling point, and in the solvent, the equilibrium state of coordination and desorption with titanium atoms contributes to stabilization, but after film formation and drying, Has an advantage that desorption proceeds rapidly and does not remain easily.
[0028]
Moreover, the size of the hydrolysis condensate of titanium alkoxide during the reaction can be controlled by using the alcohol having an ether oxygen having 3 or more carbon atoms as a solvent.
[0029]
The hydrolysis-condensation reaction of titanium tetraalkoxide is preferably 4 to 20 times mol, more preferably 5 to 12 times mol of the alcohol, and preferably 0.5 or more and less than 4 times mol of titanium tetraalkoxide. More preferably, 1 to 3.0 times mol of water is used, and in the presence of an acidic catalyst such as hydrochloric acid, sulfuric acid or nitric acid, the reaction is usually performed at a temperature in the range of 0 to 70 ° C, preferably 20 to 50 ° C. An acidic catalyst is 0.1-1.0 times mole normally with respect to titanium tetraalkoxide, Preferably it is used in 0.2-0.7 times mole.
[0030]
In the present invention, the hydrolysis-condensation reaction of the titanium tetraalkoxide is relatively stable by transesterification of the alkoxyl group by using a predetermined amount of an alcohol having an ether oxygen having 3 or more carbon atoms as a solvent. A hydrolytic condensate with little change over time is obtained. And the condensation degree of the said titanium alkoxide hydrolysis-condensation product is controlled by the light scattering intensity measurement of the said hydrolysis-condensation liquid. For example, when used as a component of the coating agent of the present invention described later, the light scattering intensity of the hydrolysis-condensation liquid is usually controlled in the range of 8,000 to 300,000 cps, preferably 9,000 to 200,000 cps. Is desirable.
[0031]
Here, the light scattering intensity Is is expressed by (Equation 1) (Is = scattered light intensity, Io = incident light intensity, n = refractive index of solvent, Mw = weight average molecular weight of solute, c = concentration of solute, ( dn / dc) = refractive index increment per solute concentration increase, λo = incident light wavelength, r = distance from sample to detector, N_A= Avogadro number), a molecular size corresponding to Mw, that is, a value proportional to the degree of condensation is observed.
[0032]
[Expression 1]

[0033]
This light scattering intensity (condensation degree) can be adjusted by the amount of water and catalyst used, the type of solvent, the hydrolysis temperature, time, and the like.
[0034]
Next, the coating agent for forming a gradient film of the present invention is obtained by hydrolysis into a reaction solution containing a hydrolysis condensate of titanium tetraalkoxide (A) and a main chain or side chain (B). When mixed with a solution containing an organic polymer compound having a silicon-containing group (coupling silicon-containing group) capable of binding to the hydrolysis condensate of titanium tetraalkoxide, and when applied to an organic substrate and dried In addition, an organic-inorganic composite gradient having a component gradient structure in which the organic base material side is substantially an organic polymer compound component and the opposite side is a titanium oxide component, and the content ratio of both is continuously changed in the film thickness direction. It consists of a coating solution capable of forming a film.
[0035]
As the reaction liquid containing the hydrolysis condensate of titanium tetraalkoxide as the component (A), as described in the above production method, an alcohol having an ether-based oxygen having 3 or more carbon atoms is used as an acid catalyst. In the presence of water, a hydrolysis-condensation reaction is performed, and the light scattering intensity of the hydrolysis-condensation liquid is usually controlled in the range of 8,000 to 300,000 cps, preferably 9,000 to 200,000 cps. .
[0036]
In the hydrolysis-condensation reaction in the component (A), by using an alcohol having an ether-based oxygen having 3 or more carbon atoms as a solvent, control of the size of the titanium alkoxide hydrolysis-condensation product during the reaction, and ( B) At the time of mixing with the solution containing the organic polymer compound of the component, rather than the increase in the molecular weight of the condensate due to the reaction between the titanium alkoxide condensates, the coupling silicon-containing group and the hydrolysis condensate of titanium alkoxide The reaction can proceed selectively.
[0037]
On the other hand, the organic polymer compound having a coupling silicon-containing group in the main chain or side chain in the component (B) includes, for example, (a) an ethylenically unsaturated monomer containing no metal, and (b) coupling. It can be obtained by copolymerizing an ethylenically unsaturated monomer having a functional silicon-containing group.
[0038]
Examples of the ethylenically unsaturated monomer containing no metal as the component (B) (a) include, for example, the general formula (I)
[0039]
[Chemical formula 5]

[0040]
(Wherein R¹Is a hydrogen atom or a methyl group, and X is a monovalent organic group. )
An ethylenically unsaturated monomer represented by formula (Ia), preferably
[0041]
[Chemical 6]

[0042]
(Wherein R¹Is a hydrogen atom or a methyl group, R²Represents a monovalent hydrocarbon group or an epoxy group, a halogen atom or a hydrocarbon group having an ether bond. )
One or two or more of ethylenically unsaturated monomers represented by
[0043]
In the ethylenically unsaturated monomer represented by the general formula (Ia), R²As a hydrocarbon group shown by C1-C10 linear or branched alkyl group, C3-C10 cycloalkyl group, C6-C10 aryl group, C7-C10 Preferred examples include aralkyl groups. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and various butyl groups, pentyl groups, hexyl groups, octyl groups, and decyl groups. Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, and a cyclooctyl group. Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a tolyl group, and a xylyl group. Examples of the aralkyl group having 7 to 10 carbon atoms, such as a group, a naphthyl group, and a methylnaphthyl group, include a benzyl group, a methylbenzyl group, a phenethylyl group, and a naphthylmethyl group. Examples of the hydrocarbon group having an epoxy group, a halogen atom or an ether bond include a linear or branched alkyl group having 1 to 10 carbon atoms and a cycloalkyl group having 3 to 10 carbon atoms having an atom or a bond. Preferred examples include an aryl group having 6 to 10 carbon atoms and an aralkyl group having 7 to 10 carbon atoms. A chlorine atom etc. are mentioned as a halogen atom of the said substituent.
[0044]
Examples of the ethylenically unsaturated monomer represented by the general formula (Ia) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl ( (Meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, glycidyl (meth) acrylate, 3-glycidoxypropyl (meth) acrylate, 2- ( 3,4-epoxycyclohexyl) ethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-bromoethyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.
[0045]
In addition to these, the ethylenically unsaturated monomer represented by the general formula (I) includes styrene, α-methylstyrene, α-acetoxystyrene, m-, o- or p-bromostyrene, m -, O- or p-chlorostyrene, m-, o- or p-vinylphenol, 1- or 2-vinylnaphthalene and the like, and stabilizers for polymerizable polymers having an ethylenically unsaturated group, for example, ethylenic Antioxidants, ultraviolet absorbers and light stabilizers having an unsaturated group can also be used. These may be used alone or in combination of two or more.
[0046]
On the other hand, as the ethylenically unsaturated monomer having a coupling silicon-containing group as the component (B) (b), for example, the general formula (II)
[0047]
[Chemical 7]

[0048]
(Wherein R^ThreeIs a hydrogen atom or a methyl group, A is an alkylene group having 1 to 4 carbon atoms, R^FourRepresents a methyl group or an ethyl group. )
Preferred examples include compounds represented by: In the general formula (II), three R^FourThey may be the same or different.
[0049]
Examples of the ethylenically unsaturated monomer represented by the general formula (II) include 2- (meth) acryloxyethyltrimethoxysilane, 2- (meth) acryloxyethyltriethoxysilane, γ- (meta ) Acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, and the like.
The ethylenically unsaturated monomer having a coupling silicon-containing group as component (b) may be used alone or in combination of two or more.
[0050]
In the presence of a radical polymerization initiator, the ethylenically unsaturated monomer containing no metal of the component (a) and the ethylenically unsaturated monomer having a coupling silicon-containing group of the component (b), By radical polymerization, an organic polymer compound having a coupling silicon-containing group used as a component of the component (B) is obtained.
[0051]
In the present invention, a solution obtained by dissolving the organic polymer compound having a coupling silicon-containing group as the component (B) thus obtained in a suitable solvent such as alcohol, ketone or ether, The reaction solution containing the hydrolysis condensate of titanium alkoxide, which is component (A), is mixed with a solution diluted as necessary, whereby the coupling silicon-containing group in the organic polymer compound is hydrolyzed, A coating agent for forming an organic-inorganic composite gradient film is obtained by selectively reacting with the hydrolysis condensate of titanium alkoxide in the reaction solution of component A). In this case, as a diluting solvent for the reaction solution containing the hydrolysis condensate of titanium alkoxide used, it is desirable to use a solvent containing an alcohol having an ether oxygen having 3 or more carbon atoms for the reason described above.
[0052]
In the present invention, in order to form a composite gradient film having a good component gradient structure, the reaction and bond between the component (A) and the silicon-containing group of the component (B) are combined with the light scattering intensity of the reaction solution. Control by measuring changes.
In this case, time after mixing (A) component and (B) component becomes important. That is, when the component (A) and the component (B) are mixed, the light scattering intensity increases with time, but it is important to use a coating agent in which the increase no longer occurs. It is also important that the light scattering intensity at that time is higher than the light scattering intensity immediately after mixing at a certain ratio.
[0053]
Therefore, the coating agent of the present invention has been a time elapsed immediately after mixing both components, and the light scattering intensity immediately after mixing the component (A) and the component (B) is X_o, The light scattering intensity of the coating agent immediately after mixing for a time_aThe light scattering intensity after leaving the coating agent at a temperature of 23 ° C. for another hour is expressed as X_{a + 1}X_a/ X_oThe value ranges from 1.2 to 10, preferably from 1.5 to 7, and (X_{a + 1}-X_a) / X_aA coating agent having a value of 0.03 or less, preferably 0.02 or less is suitable.
[0054]
X_a/ X_oWhen the value is less than 1.2, the ratio of the coupling silicon-containing group component in the component (B) is small and the number of bonding points between the component (A) and the component (B) is too small, or the component (A) Since the molecule is too small, it is difficult to obtain a good gradient material. When it exceeds 10, the ratio of the coupling silicon-containing group component in component (B) is large, and component (A) and component (B) The number of bonding points is too large, or the component molecule (A) is too large to be a uniform material, and it is difficult to obtain a good gradient material, and it is difficult to achieve the object of the present invention. .
Also (X_{a + 1}-X_a) / X_aWhen the value exceeds 0.03, the selective reaction between the component (A) and the component (B) does not proceed sufficiently, reproducibility becomes a problem, and it is difficult to achieve the object of the present invention.
[0055]
By using a coating agent having such properties, when applied to an organic base material and dried, the organic base material side is substantially an organic polymer compound component, and the opposite side is a titanium oxide component. An organic-inorganic composite gradient film having a favorable component gradient structure in which the content ratio continuously changes in the film thickness direction can be stably formed.
[0056]
In order to form a composite gradient film on an organic substrate, the coating agent of the present invention thus obtained has a dry coating thickness of usually 5 μm or less, preferably 0.01 to 1.0 μm. More preferably, the dip coating method, spin coating method, spray coating method, bar coating method, knife coating method, roll coating method, blade coating method, die coating method, gravure so as to be in the range of 0.02 to 0.7 μm. It coat | covers by well-known means, such as a coating method, volatilizes a solvent, and forms a coating film.
[0057]
Examples of the organic base material include acrylic resins such as polymethyl methacrylate, styrene resins such as polystyrene and ABS resins, olefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, and 6-nylon. Examples include substrates made of polyamide resins such as 1,6,6-nylon, polyvinyl chloride resins, polycarbonate resins, polyphenylene sulfide resins, polyphenylene ether resins, polyimide resins, and cellulose resins such as cellulose acetate. be able to.
[0058]
These organic base materials can be subjected to a surface treatment by an oxidation method, a concavo-convex method or the like, if desired, in order to further improve the adhesion with the composite gradient film according to the present invention. Examples of the oxidation method include corona discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment and the like, and examples of the unevenness method include sand blast method and solvent treatment method. Is mentioned. These surface treatment methods are appropriately selected according to the type of substrate.
[0059]
In addition, the organic base material in this invention has an organic coating film on the surface of the base material which consists of materials other than organic type materials, for example, metal-type material, glass, ceramics-type material, and other various inorganic type or metal-type materials. Also included.
In addition, confirmation of the inclined structure of the coating film can be achieved by, for example, sputtering the coating film surface to scrape the film and measuring the carbon atom and titanium atom content on the film surface over time by X-ray photoelectron spectroscopy. Can be done.
[0060]
Although there is no restriction | limiting in particular as content of the metal component in this composite gradient film, Usually in 5-98 weight% in conversion of a metal oxide, Preferably it is 20-98 weight%, Especially preferably, it is the range of 50-95 weight%. is there. The degree of polymerization and the molecular weight of the organic polymer compound are not particularly limited as long as they can be formed into a film, and may be appropriately selected according to the type of polymer compound and the desired physical properties of the gradient film material.
[0061]
The organic-inorganic composite gradient film formed using the coating agent of the present invention can be used for various applications as a functional film, and in particular, an intermediate film interposed between an organic substrate and a photocatalytically active material layer. Is preferably used.
The present invention also provides a structure having an organic-inorganic composite gradient film formed using the coating agent on an organic material, and the surface of the film is substantially a titanium oxide component.
As such a structure, a structure having antifouling properties in which a photocatalytically active material layer is provided on an organic-inorganic composite gradient film can be preferably exemplified.
[0062]
The photocatalytically active material is not particularly limited, and conventionally known materials such as titanium dioxide, strontium titanate (SrTiO).₃), Barium titanate (BaTi)₄O₉), Sodium titanate (Na₂Ti₆O₁₃), Zirconium dioxide, α-Fe₂O₃, Tungsten oxide, K₄Nb₆O₁₇, Rb₄Nb₆O₁₇, K₂Rb₂Nb₆O₁₇, Cadmium sulfide, zinc sulfide and the like. These may be used alone or in combination of two or more. Among these, titanium dioxide, particularly anatase titanium dioxide, is useful as a practical photocatalytically active material. This titanium dioxide exhibits excellent photocatalytic activity by absorbing light of a specific wavelength in the ultraviolet region contained in daily light such as sunlight.
[0063]
For the purpose of promoting photocatalytic activity, the photocatalytically active material layer in the present invention may contain a conventionally known photocatalyst promoter, if desired, together with the photocatalytic active material. Preferred examples of the photocatalyst promoter include platinum group metals such as platinum, palladium, rhodium, and ruthenium. These may be used alone or in combination of two or more. The addition amount of this photocatalyst promoter is usually selected in the range of 1 to 20% by weight based on the total weight of the photocatalytically active material and the photocatalyst promoter from the viewpoint of photocatalytic activity.
[0064]
The method for forming the photocatalytic active material layer on the organic-inorganic composite gradient film is not particularly limited, and various methods can be used. For example, PVD methods (physical vapor deposition methods) such as vacuum deposition methods and sputtering methods can be used. ) Or a metal spraying method, or a wet method using a coating solution.
[0065]
On the other hand, in the method using the coating liquid, in a suitable solvent, prepare a coating liquid consisting of a dispersion containing fine particles such as a photocatalytically active material and a photocatalyst accelerator or an inorganic binder used as necessary, This coating solution is applied onto the composite gradient film by a known method such as dip coating, spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, gravure coating. For example, a method of forming a photocatalytically active material layer by natural drying or heat drying may be used. In the case of using a photocatalyst accelerator, for example, a coating liquid containing fine particles such as a photocatalytically active material and an inorganic binder used as desired is applied on the composite gradient film to form a coating film of the photocatalytically active material, A structure in which a coating film of a photocatalytically active material is formed on the above-described composite gradient film is immersed in an aqueous solution containing metal ions of a photocatalyst promoter from which dissolved oxygen has been removed, and the metal ions are irradiated with light. A photocatalytic active material layer can also be formed by providing a photocatalyst promoter layer on a photocatalytically active material coating film by a photodeposition method of depositing on the coating surface.
[0066]
The inorganic binder used as necessary in the preparation of the coating liquid is not particularly limited as long as it can exhibit the function as a binder, and is conventionally known, for example, silicon, aluminum, titanium, zirconium, Examples thereof include oxides and hydroxides of metals such as magnesium, niobium, tungsten, tin, and tantalum, or composite oxides and hydroxides of two or more metals selected from the above metals. This inorganic binder may be used alone or in combination of two or more. In addition, the coating liquid may contain other conventionally known additive components used in the coating liquid for forming the photocatalytic active material layer, such as a silicone resin, a modified silicone resin, and a silane coupling agent. .
[0067]
In the present invention, the thickness of the photocatalytically active material layer is usually selected in the range of 10 nm to 5 μm. If this thickness is less than 10 nm, the photocatalytic function is not sufficiently exerted, and if it exceeds 5 μm, the improvement effect of the photocatalytic function is not recognized for the thickness, but rather cracks occur, and if the structure is a film or sheet, bending Cause a decrease in sex. A preferred thickness is 30 nm to 3 μm, and a range of 40 nm to 1 μm is particularly preferable.
[0068]
In the structure of the present invention, the organic material is preferably provided with a photocatalytically active material layer via an organic-inorganic composite gradient film, and the composite gradient film is substantially in contact with the photocatalytically active material layer. Since the interface is composed of only the titanium oxide component and the surface in contact with the organic material is composed of only the organic polymer compound component, the adhesion between the organic material and the composite gradient film and the photocatalytically active material layer and the composite gradient film The adhesion of is very good. In addition, since the composite gradient film is substantially only a titanium oxide compound component at the interface with the photocatalytic active material layer, deterioration of the composite gradient film due to the photocatalytic function of the photocatalytic active material layer is suppressed.
The structure of the present invention provided with such a photocatalytically active material layer has antifouling, antibacterial, and deodorizing functions, and is used for various applications that require these functions.
[0069]
【Example】
EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited at all by these examples.
[0070]
In addition, the various characteristics in each example were calculated | required by the method shown below.
(1) Measurement of light scattering intensity
The liquid to be measured was put in a glass cell, and light scattering intensity was measured with “ELS-8000” manufactured by Otsuka Electronics Co., Ltd. The measurement was performed 100 times, and the average value was obtained. At this time, the size of the pinhole was measured with a diameter of 0.3 mm on the sample side and a diameter of 0.2 mm on the detection side.
[0071]
(2) Photocatalytic durability (accelerated weathering test)
Accelerated weathering test (light source: 255 W / m) by a carbon arc type sunshine weather meter test method according to JIS K7350 [Testing machine: Sunshine weather meter “S300” manufactured by Suga Test Instruments Co., Ltd.]², Cycle: irradiation 102 minutes, irradiation + rainfall 2 minutes 1 cycle, black panel temperature: 63 ± 3 ° C., relative humidity: 55 ± 5%) for 900 hours, Nippon Denshoku Co., Ltd., Haze meter Using “NDH2000”, the haze value was measured according to JIS K7361.
[0072]
(3) Viscosity measurement of solution
The measurement was performed at a constant temperature of 30 ° C. using a vibration viscometer “VM-1-GL” manufactured by Yamauchi Electric Co., Ltd.
[0073]
(4) Tilting property of component gradient film
Using an XPS apparatus “PHI-5600” [manufactured by ULVAC-PHI Co., Ltd.], argon sputtering (4 kV) was applied at intervals of 3 minutes to scrape the film, and the content of carbon atoms and titanium atoms on the film surface was determined by X-ray photoelectron Measurement was made by spectroscopic methods to check the gradient.
Preparation example Preparation of polymer solution
In a mixed solution of 10.9 g of methyl methacrylate and 1.36 g of γ-methacryloxypropyltrimethoxysilane, 0.1 g of 2,2′-azobisisobutyronitrile was dissolved and then stirred at 75 ° C. for 3 hours. It was made to react and the copolymer whose weight average molecular weight of polystyrene conversion by a gel permeation chromatography (GPC) method is about 70,000 was obtained. 1.0 g of this copolymer was dissolved in 100 ml of methyl isobutyl ketone to obtain a polymer compound having a concentration of 10 g / L.
[0074]
Example 1
To a solution of 12.5 ml (0.042 mol) of titanium tetraisopropoxide in 16.8 ml (0.174 mol) of ethylene glycol monoethyl ether (ethyl cellosolve), 1.63 ml (0.021 mol) of concentrated nitric acid, water 0 .82 ml (0.046 mol) and ethyl cellosolve 16.8 ml (0.174 mol) mixed solution was slowly added dropwise with stirring, and then the light scattering intensity was measured at any time while stirring at 30 ° C., The increase in the degree of condensation (molecular weight) of the titanium hydrolysis-condensate was evaluated. Table 1 shows the relationship between reaction time, light scattering intensity, and solution viscosity.
[0075]
[Table 1]

[0076]
There was a correlation between the reaction time, the increase in solution viscosity, and the increase in light scattering intensity.
[0077]
Examples 2-5
In Example 1, a hydrolysis-condensation reaction of titanium tetraisopropoxide was performed in the same manner as in Example 1 except that the amounts of water and concentrated nitric acid added during the reaction were changed. Table 2 shows the measurement results of the light scattering intensity after the reaction for 4 hours.
[0078]
[Table 2]

[0079]
The viscosity of the solution increases depending on the reaction conditions (in general, hydrolysis-condensation of titanium alkoxide increases as the amount of water added increases and the amount of catalyst added decreases), and the light scattering intensity measured this time is correlated. It was confirmed that
[0080]
Example 6
18.3 ml of ethyl cellosolve and 20 ml of methyl isobutyl ketone were added to 8.3 ml of the titanium hydrolyzate-condensate solution obtained in Example 3 to prepare a mixed solution. The light scattering intensity was measured every arbitrary time after mixing this solution, and the reaction state of both components was evaluated. Table 3 shows the relationship between the mixing elapsed time and the light scattering intensity. It was confirmed that the light scattering intensity increased according to the elapsed time after mixing, and the reaction between the titanium hydrolyzate and the organic polymer compound proceeded.
[0081]
Comparative Example 1
The same procedure as in Example 6 was performed except that the polymer compound solution obtained without using γ-methacryloxypropyltrimethoxysilane was used in the preparation example. Table 3 shows the relationship between the mixing elapsed time and the light scattering intensity.
[0082]
[Table 3]

[0083]
Example 7
In a solution of 12.5 ml (0.042 mol) of titanium tetraisopropoxide in 16.8 ml (0.174 mol) of ethylene glycol monoethyl ether (ethyl cellosolve), 1.63 ml (0.021 mol) of concentrated nitric acid, water 0 A mixed solution of .82 ml (0.046 mol) and ethyl cellosolve 16.8 ml (0.174 mol) was slowly added dropwise with stirring, and then stirred at 30 ° C. for 4 hours to conduct a hydrolysis-condensation reaction to obtain a reaction solution. It was. The light scattering intensity of this reaction solution was measured and found to be 12,000 cps.
[0084]
Next, 16.7 ml of ethyl cellosolve, 20 ml of methyl isobutyl ketone, and 5 ml of the polymer compound solution obtained in Preparation Example were added to 8.3 ml of the reaction solution to prepare a mixed solution. The light scattering intensity immediately after that was measured and found to be 5,000 cps. Subsequently, after stirring this for about 20 hours at room temperature (23 degreeC), after performing the selective reaction of the hydrolysis condensate of titanium tetraisopropoxide and the coupling | bonding silicon containing group site | part of a high molecular compound. When the light scattering intensity was measured, it was 9,800 cps. A part of this solution was taken, stirred at 23 ° C. for an additional hour, and the light scattering intensity was measured. The result was 9,870 cps. Therefore, X_a/ X_oThe value is 1.96 and (X_{a + 1}-X_a) / X_aThe value was 0.01.
[0085]
The coating liquid obtained by stirring for 20 hours was subjected to a polyethylene terephthalate (PET) film having a thickness of 50 μm using a Mayer bar having a wire diameter of 0.075 mm [“Tetron HB-3” manufactured by Teijin DuPont Films Ltd.] ] A bar coating was applied to the film, and the solvent was volatilized to form a 70 nm thick composite gradient film. The XPS measurement result of this inclined film is shown in FIG. From this figure, it was confirmed that the film has a gradient.
[0086]
Next, a photocatalyst solution “ST-K211” manufactured by Ishihara Sangyo Co., Ltd. was applied on the film to provide a photocatalyst film having a thickness of 50 nm. When the accelerated weathering test was performed on this film with a photocatalyst film, the haze value after the lapse of 900 hours was 3.78%, and the transparency was maintained.
[0087]
Example 8
A coating liquid mixture was prepared in the same manner as in Example 7 except that 10 ml of methyl isobutyl ketone and 10 ml of the polymer compound solution obtained in the preparation example were used. The light scattering intensity immediately after that was measured and found to be 6,000 cps. Subsequently, after stirring this for about 20 hours at room temperature (23 degreeC), after performing the selective reaction of the hydrolysis condensate of titanium tetraisopropoxide and the coupling | bonding silicon containing group site | part of a high molecular compound. When the light scattering intensity was measured, it was 14,800 cps. A part of this solution was taken, stirred at 23 ° C. for another 1 hour, and the light scattering intensity was measured. As a result, it was 15,000 cps. Therefore, X_a/ X_oThe value is 2.46 and (X_{a + 1}-X_a) / X_aThe value was 0.01.
[0088]
Using the coating solution obtained by stirring for 20 hours, a composite gradient film having a thickness of 75 nm was formed on a PET film in the same manner as in Example 7.
Next, a photocatalytic film having a thickness of 50 nm was provided on the film in the same manner as in Example 7. When the accelerated weather resistance test was performed on this film with a photocatalyst film, the haze value after 900 hours was 3.5%, and the transparency was maintained.
[0089]
Example 9
A coating liquid mixture was prepared in the same manner as in Example 7 except that 5 ml of methyl isobutyl ketone and 15 ml of the polymer compound solution obtained in the preparation example were used. When the light scattering intensity immediately after that was measured, it was 5,700 cps. Subsequently, after stirring this for about 20 hours at room temperature (23 degreeC), after performing the selective reaction of the hydrolysis condensate of titanium tetraisopropoxide and the coupling | bonding silicon containing group site | part of a high molecular compound. When the light scattering intensity was measured, it was 19,300 cps. A part of this solution was taken, stirred at 23 ° C. for an additional hour, and the light scattering intensity was measured and found to be 19,400 cps. Therefore, X_a/ X_oThe value is 3.39 and (X_{a + 1}-X_a) / X_aThe value was 0.01.
[0090]
Using the coating solution obtained by stirring for 20 hours, a composite gradient film having a thickness of 80 nm was formed on a PET film in the same manner as in Example 7.
Next, a photocatalytic film having a thickness of 50 nm was provided on the film in the same manner as in Example 7. When an accelerated weather resistance test was performed on this film with a photocatalyst film, the haze value after 900 hours was 4.0%, and the transparency was maintained.
[0091]
Example 10
In Example 7, a hydrolysis-condensation reaction of titanium tetraisopropoxide was performed in the same manner as in Example 7 except that the amount of water was changed to 1.23 ml (0.069 mol). The light scattering intensity of this reaction solution was measured and found to be 250,000 cps.
[0092]
Next, 18.3 ml of ethyl cellosolve, 20 ml of methyl isobutyl ketone, and then 5 ml of the polymer compound solution obtained in the preparation example were added to 8.3 ml of this reaction solution to prepare a mixed solution. The light scattering intensity immediately after that was measured and found to be 100,000 cps. Subsequently, after stirring this for about 20 hours at room temperature (23 degreeC), after performing the selective reaction of the hydrolysis condensate of titanium tetraisopropoxide and the coupling | bonding silicon containing group site | part of a high molecular compound. The light scattering intensity was measured and found to be 210,000 cps. A part of this solution was taken, stirred at 23 ° C. for another 1 hour, and the light scattering intensity was measured, and it was 211,500 cps. Therefore, X_a/ X_oThe value is 2.10 and (X_{a + 1}-X_a) / X_aThe value was 0.01.
[0093]
Using the coating solution obtained by stirring for 20 hours, a composite gradient film having a thickness of 70 nm was formed on a PET film in the same manner as in Example 7. The XPS measurement result of this inclined film is shown in FIG. From this figure, it was confirmed that the film has a gradient.
[0094]
Next, a photocatalytic film having a thickness of 50 nm was provided on the film in the same manner as in Example 7. When an accelerated weather resistance test was performed on this film with a photocatalyst film, the haze value after 4.5 hours was 4.5%, and the transparency was maintained.
[0095]
Example 11
In Example 7, a hydrolysis-condensation reaction of titanium tetraisopropoxide was performed in the same manner as in Example 7 except that ethylene glycol monomethyl ether (methyl cellosolve) was used as a solvent. The light scattering intensity of this reaction solution was measured and found to be 9,000 cps.
[0096]
Next, 16.7 ml of methyl cellosolve, 20 ml of methyl isobutyl ketone, and then 5 ml of the polymer compound solution obtained in the preparation example were added to 8.3 ml of this reaction solution to prepare a mixed solution. When the light scattering intensity immediately after that was measured, it was 3,500 cps. Subsequently, after stirring this for about 20 hours at room temperature (23 degreeC), after performing the selective reaction of the hydrolysis condensate of titanium tetraisopropoxide and the coupling | bonding silicon containing group site | part of a high molecular compound. The light scattering intensity was measured and found to be 7,000 cps. A part of this solution was taken, further stirred at 23 ° C. for 1 hour, and the light scattering intensity was measured and found to be 7,150 cps. Therefore, X_a/ X_oThe value is 2.00 and (X_{a + 1}-X_a) / X_aThe value was 0.02.
[0097]
Using the coating solution obtained by stirring for 20 hours, a composite gradient film having a thickness of 70 nm was formed on a PET film in the same manner as in Example 7. The XPS measurement result of this inclined film is shown in FIG. From this figure, it was confirmed that the film has a gradient.
[0098]
Next, a photocatalytic film having a thickness of 50 nm was provided on the film in the same manner as in Example 7. When an accelerated weather resistance test was performed on this film with a photocatalyst film, the haze value after lapse of 900 hours was 2.9%, and the transparency was maintained.
[0099]
Comparative Example 2
In Example 7, the hydrolysis-condensation reaction of titanium tetraisopropoxide was performed in the same manner as in Example 7 except that the amount of water was changed to 1.64 ml (0.092 mol). The light scattering intensity of this reaction solution was measured and found to be 350,000 cps.
[0100]
Next, 18.3 ml of ethyl cellosolve, 20 ml of methyl isobutyl ketone, and then 5 ml of the polymer compound solution obtained in the preparation example were added to 8.3 ml of this reaction solution to prepare a mixed solution. When the light scattering intensity immediately after that was measured, it was 150,000 cps. Subsequently, after stirring this for about 20 hours at room temperature (23 degreeC), after performing the selective reaction of the hydrolysis condensate of titanium tetraisopropoxide and the coupling | bonding silicon containing group site | part of a high molecular compound. When the light scattering intensity was measured, it was 170,000 cps. A part of this solution was taken, further stirred at 23 ° C. for 1 hour, and the light scattering intensity was measured, and it was 174,900 cps. Therefore, X_a/ X_oThe value is 1.13 and (X_{a + 1}-X_a) / X_aThe value was 0.03.
[0101]
Using the coating solution obtained by stirring for 20 hours, a composite film having a thickness of 70 nm was formed on a PET film in the same manner as in Example 7. The XPS measurement result of this composite film is shown in FIG. From this figure, it was confirmed that the component (A) and the component (B) are almost uniform.
[0102]
Next, a photocatalyst film having a thickness of 50 nm was provided on the film in the same manner as in Example 7. When this accelerated film was subjected to an accelerated weathering test, the haze value after lapse of 900 hours was 10% and clouded.
[0103]
Comparative Example 3
In Example 7, a hydrolysis-condensation reaction of titanium tetraisopropoxide was performed in the same manner as in Example 7 except that isopropyl alcohol was used as a solvent. The light scattering intensity of this reaction solution was measured and found to be 20,000 cps.
[0104]
Next, 18.3 ml of isopropyl alcohol, 20 ml of methyl isobutyl ketone, and then 5 ml of the polymer compound solution obtained in Preparation Example were added to 8.3 ml of this reaction solution to prepare a mixed solution. The light scattering intensity immediately after that was measured and found to be 10,000 cps. Subsequently, after stirring this for about 20 hours at room temperature (23 degreeC), after performing the selective reaction of the hydrolysis condensate of titanium tetraisopropoxide and the coupling | bonding silicon containing group site | part of a high molecular compound. The light scattering intensity was measured and found to be 110,000 cps. A part of this solution was taken and stirred at 23 ° C. for an additional hour, and the light scattering intensity was measured to be 119,000 cps. Therefore, X_a/ X_oThe value is 11.0 and (X_{a + 1}-X_a) / X_aThe value was 0.08.
[0105]
Using the coating solution obtained by stirring for 20 hours, a composite film having a thickness of 70 nm was formed on a PET film in the same manner as in Example 7. The XPS measurement result of this composite film is shown in FIG. From this figure, it was confirmed that the component (A) and the component (B) are almost uniform.
[0106]
Next, a photocatalyst film having a thickness of 50 nm was provided on the film in the same manner as in Example 7. When this accelerated film weather resistance test was performed on the film with the photocatalyst film, the haze value after 900 hours was 15% and it was cloudy.
[0107]
【The invention's effect】
According to the present invention, when a titanium alkoxide hydrolyzed condensate is produced, a method for efficiently controlling the degree of condensation thereof, and when applied to an organic base material and dried, the organic base material side is substantially an organic polymer compound component. An inclined film that can stably form an organic-inorganic composite gradient film having a favorable component gradient structure in which the opposite side is a titanium oxide component and the content ratio of both components continuously changes in the film thickness direction. A forming coating agent can be provided.
[0108]
In addition, by using this coating agent, an inclined film is formed on an organic material, and a photocatalyst layer is further provided thereon, whereby a structure having antifouling properties and excellent durability can be obtained.
[Brief description of the drawings]
1 is a graph showing the relationship between the sputtering time and the content of carbon atoms and titanium atoms in a composite film formed in Example 7. FIG.
2 is a graph showing the relationship between the sputtering time and the content of carbon atoms and titanium atoms in the composite film formed in Example 10. FIG.
3 is a graph showing the relationship between the sputtering time and the carbon atom and titanium atom contents in the composite film formed in Example 11. FIG.
4 is a graph showing the relationship between the sputtering time and the carbon atom content and the titanium atom content in the composite film formed in Comparative Example 2. FIG.
5 is a graph showing the relationship between the sputtering time and the carbon atom content and the titanium atom content in the composite film formed in Comparative Example 3. FIG.

Claims (8)

  When titanium tetraalkoxide is hydrolyzed and condensed in an organic solvent to produce a titanium alkoxide hydrolyzed condensate, the degree of condensation of the resulting hydrolyzed condensate is determined by light scattering of the reaction solution containing the hydrolyzed condensate. A method for producing a titanium alkoxide hydrolyzed condensate, characterized by controlling by strength measurement.   The method according to claim 1, wherein the organic solvent is a solvent containing an alcohol having an etheric oxygen having 3 or more carbon atoms. A method for producing an organic-inorganic composite gradient film having a component gradient structure,
(A) a reaction solution containing a hydrolysis condensate of titanium tetraalkoxide, and (B) an organic compound having a silicon-containing group capable of binding to the hydrolysis condensate of titanium tetraalkoxide by hydrolysis in the main chain or side chain. A coating agent formed by mixing a solution containing a polymer compound is applied to an organic substrate ,
The reaction of the silicon-containing group of the organic polymer compound (A) and the hydrolytic condensate of components in the component (B), the coupling, while controlling the measurement of change in light scattering intensity of the reaction solution, the reaction, Make a bond
Substantially organic substrate side with an organic polymer compound component, an opposite side of the titanium oxide component, the organic having the component gradient structure that the content of both changes continuously in the thickness direction - inorganic composite graded film A method for producing an organic-inorganic composite gradient film characterized by comprising: The method according to claim 3, wherein a solvent containing an alcohol having an ether oxygen having 3 or more carbon atoms is added as a diluting solvent at the time of mixing (A) and (B) or after mixing. The organic polymer compound used for the component (B) is (a) the general formula (Ia)

(In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a monovalent hydrocarbon group.)
An ethylenically unsaturated monomer represented by formula (b):

(In the formula, R ³ represents a hydrogen atom or a methyl group, A represents an alkylene group having 1 to 4 carbon atoms, and R ⁴ represents a methyl group or an ethyl group.)
The method of Claim 3 or 4 which is a copolymer with the ethylenically unsaturated monomer represented by these. The method according to claim 3, 4 or 5, wherein the light scattering intensity of the component (A) is 8,000 to 300,000 cps. On the organic material, according to claim 3 to organic using the method according to any one of the 6 - Rukoto be composed of inorganic composite graded film is formed, and substantially the titanium oxide component the film surface A structure manufacturing method characterized by the above. Organic - inorganic composite graded film, the method described in 請 Motomeko 7 Ru provided a photocatalytic active material layer.

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