JP4338346B2 - Dye-sensitized solar cell - Google Patents

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【００１８】
（式中、Ｒ¹は水素原子または炭素数１〜８の炭化水素基を表し、Ｒ²は水素原子、ハロゲン原子、炭素数１〜８のアルキル基、炭素数１〜４のアルコキシ基、シアノ基またはニトロ基を表し、Ｒ³は炭素数１〜１２の直鎖状もしくは枝分れ鎖状のアルキレン基または−Ｏ−Ｒ’−（Ｒ’は炭素数２または３の直鎖状もしくは枝分れ鎖状のアルキレン基を合わす）を表し、Ｒ⁴は水素原子またはメチル基を表す）で表されるベンゾトリアゾール系モノマー（Ａ−１）。
【００１９】
【化２】

【００２０】
（式中、Ｒ¹、Ｒ⁴は上記と同じ意味を表し、Ｒ⁵は水素原子または水酸基を表し、Ｒ⁶は水素原子または炭素数１〜６のアルコキシ基を表し、Ｒ⁷は炭素数１〜１２の直鎖状もしくは枝分れ鎖状のアルキレン基を表す。）で表されるベンゾフェノン系モノマー（Ａ−２）。
【００２１】
【化３】

【００２２】
(式中、Ｒ⁴は上記と同じ意味を表し、Ｒ⁸は直接結合、−（ＣＨ₂ＣＨ₂Ｏ）_p−または−ＣＨ₂ＣＨ（ＯＨ）−ＣＨ₂Ｏ−を表し、ｐは１〜５の整数を表す。Ｒ⁹，Ｒ¹⁰，Ｒ¹¹，Ｒ¹²，Ｒ¹³，Ｒ¹⁴，Ｒ¹⁵，Ｒ¹⁶は各々独立して水素原子、炭素数１〜１０のアルコキシ基、アルケニル基またはアルキル基を表す。)で表されるトリアジン系モノマー（Ａ−３）。
【００２３】
モノマー（Ａ−１）の好ましい具体例としては、例えば２−［２'−ヒドロキシ−５'−（メタ）アクリロイルオキシメチルフェニル］−２Ｈ−ベンゾトリアゾール、２−［２'−ヒドロキシ−５'−（メタ）アクリロイルオキシエチルフェニル］−２Ｈ−ベンゾトリアゾール、２−［２'−ヒドロキシ−５'−（メタ）アクリロイルオキシプロピルフェニル］−２Ｈ−ベンゾトリアゾール、２−［２'−ヒドロキシ−５'−（メタ）アクリロイルオキシヘキシルフェニル］−２Ｈ−ベンゾトリアゾール、２−［２'−ヒドロキシ−３'−ｔｅｒｔ−ブチル−５'−（メタ）アクリロイルオキシエチルフェニル］−２Ｈ−ベンゾトリアゾール、２−〔２'−ヒドロキシ−５'−（β−（メタ）アクリロイルオキシエトキシ）−３'−ｔｅｒｔ−ブチルフェニル〕−５−ｔｅｒｔ−ブチル−２Ｈ−ベンゾトリアゾール等が挙げられる。
【００２４】
モノマー（Ａ−２）の具体例としては、２−ヒドロキシ−４−[２−(メタ)アクリロイルオキシ]エトキシベンゾフェノン、２−ヒドロキシ−４−[２−(メタ)アクリロイルオキシ]ブトキシベンゾフェノン、２，２'−ジヒドロキシ−４−[２−(メタ)アクリロイルオキシ]エトキシベンゾフェノン、２−ヒドロキシ−４−[２−(メタ)アクリロイルオキシ]エトキシ−４'−(２−ヒドロキシエトキシ)ベンゾフェノン、２−ヒドロキシ−３−ｔｅｒｔ−ブチル−４−[２−(メタ)アクリロイルオキシ]エトキシベンゾフェノン、２−ヒドロキシ−３−ｔｅｒｔ−ブチル−４−[２−(メタ)アクリロイルオキシ]ブトキシベンゾフェノン等を挙げることができる。
【００２５】
モノマー（Ａ−３）の具体例としては、例えば２，４−ジフェニル−６−[２−ヒドロキシ−４−(２−アクリロイルオキシエトキシ)]−ｓ−トリアジン、２，４−ビス(２−メチルフェニル)−６−[２−ヒドロキシ−４−(２−アクリロイルオキシエトキシ)]−ｓ−トリアジン、２，４−ビス(２−メトキシフェニル)−６−[２−ヒドロキシ−４−(２−アクリロイルオキシエトキシ)]−ｓ−トリアジン等を挙げることができる。
【００２６】
なお、モノマー（Ａ−１）および／またはモノマー（Ａ−２）を使用する場合、紫外線遮蔽層にアルカリ金属や塩基性の強い塩基性化合物が共存すると、紫外線遮蔽層の着色の問題や経時的な紫外線吸収性能の低下を招き易いため、これらを抑制する点から、各々の一般式中のＲ¹がＯＨ基に隣接した位置である３位にあり、炭素数４〜８のアルキル基であるモノマーの使用が特に好ましい。
【００２７】
上記紫外線吸収性基を有するモノマー（Ａ−１）〜（Ａ−３）は、各々化合物特有の紫外線吸収特性を有しているため、求められる紫外線遮蔽性能に応じて、単独で使用したり２種以上を適宜組み合わせて使用することが好ましい。
【００２８】
各種金属酸化物系半導体は、固有の劣化波長を有しており、例えば、二酸化チタンは４１０ｎｍ以下の紫外線を吸収し、この全波長が光触媒作用を引き起こすため、トリアジン系モノマー（Ａ−３）を単独で使用するよりも、ベンゾフェノン系モノマー（Ａ−２）やベンゾトリアゾール系モノマー（Ａ−１）をそれぞれ単独で使用することが好ましい。最も好ましいのは、モノマー（Ａ−１）または（Ａ−２）と、モノマー（Ａ−３）との２種併用パターンである。
【００２９】
なお、上記紫外線吸収性基を有するモノマー（Ａ−１）〜（Ａ−３）を各々単独で重合し、もしくは２種以上を適宜共重合することによって得られるポリマーを、単独であるいは２種以上を紫外線遮蔽層形成用樹脂組成物に含有させてもよい。
【００３０】
モノマー混合物（Ｉ）には、炭素数４以上のアルキル基を有するモノマー（Ｂ）か、紫外線安定性基を有するモノマー（Ｃ）の何れか一方または両方が含まれていなければならない。これらは、上記した紫外線吸収性基を有するモノマー（Ａ）の紫外線吸収性基あるいは後述する添加型紫外線吸収剤の有する紫外線吸収性基が、長時間の紫外線曝露によって次第に光分解してしまうのを防ぐ作用効果を有する。
【００３１】
（Ｂ）炭素数４以上のアルキル基を有するモノマー
このモノマー（Ｂ）としては、具体的には、下記一般式で表される（メタ）アクリレート系モノマーが好ましく用いられる。
【００３２】
【化４】

【００３３】
（式中、Ｒ¹⁷は水素原子またはメチル基を表わし、Ｘは炭素数が４以上の炭化水素基を表わす）。
【００３４】
上記式中、Ｘで表される置換基は、シクロヘキシル基、メチルシクロヘキシル基、シクロドデシル基等の炭素数４以上の脂環式炭化水素基；ブチル基、イソブチル基、ｔｅｒｔ−ブチル基、２−エチルヘキシル基、ヘプチル基、オクチル基、ノニル基、デシル基、ウンデシル基、ドデシル基、ペンタデシル基、オクタデシル基等の炭素数４以上の直鎖状または分枝鎖状のアルキル基；ボルニル基、イソボルニル基等の炭素数４以上の多環式炭化水素基であり、中でも脂環式炭化水素基、分枝鎖状アルキル基、炭素数６以上の直鎖状アルキル基が好ましい。
【００３５】
モノマー（Ｂ）のより具体的な例としては、例えばシクロヘキシル（メタ）アクリレート、メチルシクロヘキシル（メタ）アクリレート、シクロドデシル（メタ）アクリレート、ｔｅｒｔ−ブチルシクロヘキシル（メタ）アクリレート、イソブチル（メタ）アクリレート、ｔｅｒｔ−ブチル（メタ）アクリレート、ラウリル（メタ）アクリレート、イソボルニル（メタ）アクリレート、ステアリル（メタ）アクリレート、２−エチルヘキシル（メタ）アクリレート等が非限定的に挙げられ、これらの１種または２種以上が使用できる。
【００３６】
（Ｃ）紫外線安定性基を有するモノマー
紫外線安定性基を有するモノマー（Ｃ）を共重合させると、前記した紫外線吸収性基の光分解抑制効果が発揮される他に、紫外線遮蔽層に紫外線安定性が付与され、遮蔽効果が一層高まる。紫外線安定性基を有するモノマー（Ｃ）とは、分子中にラジカル重合性二重結合と紫外線安定性基を同時に有するものであれば特にその種類は限定されないが、中でも特に好ましいのは、下記一般式（Ｃ−１）や(Ｃ−２)で示されるモノマーである。
【００３７】
【化５】

【００３８】
（式中、Ｒ¹⁸は水素原子またはシアノ基を表し、Ｒ¹⁹、Ｒ²⁰はそれぞれ独立して水素原子またはメチル基を表し、Ｒ²¹は水素原子または炭化水素基を表し、Ｙは酸素原子またはイミノ基を表す。）
【００３９】
【化６】

【００４０】
（式中、Ｒ²²は水素原子またはシアノ基を表し、Ｒ²³、Ｒ²⁴、Ｒ²⁵、Ｒ²⁶はそれぞれ独立して水素原子またはメチル基を表し、Ｚは酸素原子またはイミノ基を表す。）。
【００４１】
上記モノマー（Ｃ−１）の具体例としては、４−（メタ）アクリロイルオキシ−２，２，６，６−テトラメチルピペリジン、４−（メタ）アクリロイルアミノ−２，２，６，６−テトラメチルピペリジン、４−（メタ）アクリロイルオキシ−１，２，２，６，６−ペンタメチルピペリジン、４−（メタ）アクリロイルアミノ−１，２，２，６，６−ペンタメチルピペリジン、４−シアノ−４−（メタ）アクリロイルアミノ−２，２，６，６−テトラメチルピペリジン、４−クロトノイルオキシ−２，２，６，６−テトラメチルピペリジン、４−クロトノイルアミノ−２，２，６，６−テトラメチルピペリジン等が非限定的に挙げられ、これらは単独でも、必要により２種以上を適宜組み合わせて使用しても構わない。
【００４２】
上記モノマー（Ｃ−２）の具体例としては、１−（メタ）アクリロイル−４−（メタ）アクリロイルアミノ−２，２，６，６−テトラメチルピペリジン、１−（メタ）アクリロイル−４−シアノ−４−（メタ）アクリロイルアミノ−２，２，６，６−テトラメチルピペリジン、１−クロトノイル−４−クロトノイルオキシ−２，２，６，６−テトラメチルピペリジン等が非限定的に挙げられ、これらも単独でも、必要により２種以上を適宜組み合わせて使用してもよい。
【００４３】
本発明の第１の紫外線遮蔽層形成用樹脂組成物の主成分となるポリマーを合成するために用いられるモノマー混合物（Ｉ）には、これまで説明した紫外線吸収性基を有するモノマー（Ａ）と、炭素数４以上のアルキル基を有するモノマー（Ｂ）および／または紫外線安定性基を有するモノマー（Ｃ）が必須モノマーとして含まれる。一方、本発明の第２のタイプに用いられるモノマー混合物(II)においては、炭素数４以上のアルキル基を有するモノマー（Ｂ）および／または紫外線安定性基を有するモノマー（Ｃ）が必須成分である。第２のタイプの樹脂組成物には、後述する添加型紫外線吸収剤が必須成分として配合されるため、紫外線吸収性基を有するモノマー（Ａ）を必須モノマーとする必要がないのである。ただし、モノマー混合物（II）に上記モノマー（Ａ）が含まれていても構わない。
【００４４】
モノマー混合物（Ｉ）あるいはモノマー混合物(II)では、上記必須モノマー以外に、紫外線遮蔽層の物性を適宜変更するため等の必要に応じて、以下の各種モノマー類を併用してもよい。
【００４５】
（Ｄ）その他のモノマー
その他のモノマー（Ｄ）の具体例としては、メチル（メタ）アクリレート、エチル（メタ）アクリレート等の炭素数３以下のアルキル基を有する（メタ）アクリレート（Ｄ−１とする）が好ましいものとして挙げられる。これらのモノマー（Ｄ−１）は前記したモノマー（Ａ）〜（Ｃ）との共重合性に優れ、硬く、耐水性や機械的強度に優れた遮蔽層を形成する役割を担う上、安価なため使いやすい。中でも、ホモポリマーのＴｇが高いメチルメタクリレートが特に好ましい。
【００４６】
また、架橋性官能基を有するモノマー（Ｄ−２）を用いてポリマーを合成し、別途硬化剤（架橋剤）を配合することによって、紫外線遮蔽層を架橋させてもよい。架橋性官能基を有するモノマー（Ｄ−２）の具体例としては、（メタ）アクリル酸、イタコン酸、無水マレイン酸等のカルボキシル基を有するモノマー；２−（メタ）アクリロイルオキシエチルアシッドホスフェート等の酸性リン酸エステル系モノマー；グリシジル（メタ）アクリレート、メチルグリシジル（メタ）アクリレート、脂環式エポキシ基含有（メタ）アクリレート（例えば、ダイセル化学工業社製；商品名「ＣＹＣＬＯＭＥＲ Ｍ−１００」）等のエポキシ基含有（メタ）アクリレート；２−ヒドロキシエチル（メタ）アクリレート、４−ヒドロキシブチル（メタ）アクリレート、水酸基末端可撓性（メタ）アクリレート（例えば、ダイセル化学工業株式会社製；商品名「プラクセルＦＭ」）等の活性水素（ヒドロキシル）基を有するモノマー等が使用可能である。これらの中でも、ヒドロキシル基含有モノマーを用いると共に、紫外線遮蔽層用樹脂組成物に硬化剤としてポリイソシアネートを含有させて、ヒドロキシル基とイソシアネート基の反応によって紫外線遮蔽層を架橋させるのが好ましい。
【００４７】
また、その他のモノマーとして、（メタ）アクリルアミド、イミド（メタ）アクリレート、Ｎ−メチロール（メタ）アクリルアミド等の含窒素モノマー；エチレングリコールジ（メタ）アクリレート等の２個の重合性二重結合を有するモノマー；塩化ビニル等のハロゲン含有モノマー；スチレン、α−メチルスチレン等の芳香族系モノマー；ビニルエーテル等を用いることもできる。
【００４８】
（Ｅ）反応性シリル基含有モノマー
モノマー混合物（Ｉ）または(II)には、反応性シリル基含有モノマー（便宜上モノマー（Ｅ）とする）が含まれていてもよい。モノマー（Ｅ）は、架橋性官能基含有モノマーとして作用する上、これを使用して合成したポリマーを紫外線遮蔽層に用いると、例えば太陽電池の基材がガラスであり、紫外線遮蔽層を直接ガラス基板上に形成する場合に、ガラス基板と紫外線遮蔽層の密着性が高まるため、好ましい実施態様である。
【００４９】
反応性シリル基含有モノマー（Ｅ）とは、少なくとも末端に反応性シリル基を有すると共に重合性二重結合を有するモノマーである。そして、末端の反応性シリル基がモノマー中の炭素原子に直結しているタイプ（Ｅ−１）と、末端の反応性シリル基が、置換基を有していてもよいポリシロキサン結合を介して、モノマー中の炭素原子と連結しているタイプ（Ｅ−２）に分けることができ、いずれも使用可能である。モノマー（Ｅ−２）は、モノマー（Ｅ−１）に有機シラン化合物を反応させることにより得られる。通常のポリシロキサン結合とは−ＳｉＨ₂−Ｏ−ＳｉＨ₂−Ｏ−のことであるが、モノマー（Ｅ−２）におけるポリシロキサン結合は置換基を有していてもよい。すなわち、Ｓｉに結合するいずれか１個以上の水素原子が、炭素数１〜６のアルコキシ（アルキルオキシ）基か炭素数１〜１０のアルキル基と置換されていてもよい。もちろん各置換基は同一でも異なっていても構わない。置換基としてアルコキシ基が存在すればポリシロキサン結合部分にも反応性シリル基が存在することとなる。なお、反応性シリル基とは、加水分解性シリル基を意味し、加水分解反応によってシラノール（Ｓｉ−ＯＨ）基を生成することのできる官能基全てを意味する。
【００５０】
炭素原子に直結する反応性シリル基を有するモノマー（Ｅ−１）は、重合性二重結合と、炭素原子に直結する反応性シリル基を有している。具体例としては、下記一般式（Ｅ−１−１）〜（Ｅ−１−３）で示される。
【００５１】
【化７】

【００５２】
（式中、Ｒ²⁷は水素原子またはメチル基を表わし、Ｒ²⁸は炭素数１〜６の炭化水素基を表わし、ａは１〜５の整数、ｂは０または１を表わす）
【００５３】
【化８】

【００５４】
（式中、Ｒ²⁹は前記Ｒ²⁸と同じ意味もしくはアルキルオキシアルキル基を表わし、ｃは０または１を表わす）
【００５５】
【化９】

【００５６】
（式中、Ｒ³⁰はＲ²⁸と同じ意味、ｄは０または１を表わす）。
【００５７】
前記モノマー（Ｅ−１−１）は、加水分解性のアルコキシシリル基と、（メタ）アクリロイル基を有するモノマーであり、各一般式において、炭素数１〜６の炭化水素基とは、メチル基、エチル基、プロピル基等のアルキル基；ビニル基、イソプロペニル基、アリル基等のアルケニル基；フェニル基等のアリール基を表わす。
【００５８】
モノマー（Ｅ−１−１）の具体例としては、３−（メタ）アクリロキシプロピルトリメトキシシラン、３−（メタ）アクリロキシプロピルトリエトキシシラン、３−（メタ）アクリロキシプロピルトリブトキシシラン、３−（メタ）アクリロキシプロピルトリイソプロペノキシシラン、（メタ）アクリロキシメチルトリメトキシシラン、（メタ）アクリロキシメチルトリエトキシシラン、（メタ）アクリロキシメチルトリブトキシシラン等が挙げられる。
【００５９】
取り扱い易さや反応性、架橋密度等を考慮すれば、特に好ましいのは、３−（メタ）アクリロキシプロピルトリメトキシシラン、３−（メタ）アクリロキシトリエトキシシラン、３−（メタ）アクリロキシプロピルメチルジメトキシシランである。またモノマー（Ａ）〜（Ｃ）との共重合性の点では、ビニル官能性のモノマー（Ｅ−１−２）や（Ｅ−１−３）よりも、（メタ）アクリロイル基を有する（Ｅ−１−１）が好ましい。
【００６０】
モノマー（Ｅ−１−２）は、ビニル基と加水分解性のアルコキシシリル基を有するビニル官能性モノマーであり、前記モノマー（Ｅ−１−３）は、ビニル官能性アルコキシシラン化合物である。
【００６１】
モノマー（Ｅ−１−２）としては、ビニルトリメトキシシラン、ビニルトリエトキシシラン、ビニルトリアセトキシシラン、ビニルメチルジメトキシシラン、ビニルメチルジエトキシシラン等が挙げられ、モノマー（Ｅ−１−３）としては、３−ビニロキシプロピルトリメトキシシラン、３−ビニロキシプロピルトリエトキシシラン、３−ビニロキシプロピルメチルジメトキシシラン等が挙げられる。これらの中では、取り扱い易さや反応性の観点から、ビニルトリメトキシシラン、ビニルトリエトキシシラン、３−ビニロキシプロピルトリメトキシシラン等が好ましい。
【００６２】
上記炭素原子に直結する反応性シリル基を有するモノマー（Ｅ−１）に有機シラン化合物を反応させることにより、末端の反応性シリル基が、前記ポリシロキサン結合を介して、モノマー中の炭素原子に結合した構造のモノマー（Ｅ−２）が得られる。用いることのできる有機シラン化合物は、下記一般式で示される有機シラン化合物および／またはその加水分解縮合物である。
【００６３】
Ｒ³¹ _mＳｉ（ＯＲ³²）_n …（Ｅ）
（式中、Ｒ³¹は同一または異なっていてもよく、水素原子、低級アルキル基、アリール基、ビニル基または炭素鎖に直結したメルカプト基、またはメタクリロイル基を表し、Ｒ³²は同一または異なっていてもよく、水素原子、低級アルキル基またはアシル基を表し、ｍは０または正の整数、ｎは１以上の整数でかつｍ＋ｎはＳｉの原子価と一致する）
【００６４】
具体的には、テトラメトキシシラン、テトラエトキシシラン、テトライソプロポキシシラン、テトラブトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、メチルトリイソプロポキシシラン、メチルトリブトキシシラン、エチルトリメトキシシラン、エチルトリエトキシシラン、エチルトリイソプロポキシシラン、エチルトリブトキシシラン、ジメチルジメトキシシラン、ジメチルジエトキシシラン、ジメチルジイソプロポキシシラン、ジメチルジブトキシシラン、ジエチルジメトキシシラン、ジエチルジエトキシシラン、ジエチルジイソプロポキシシラン、ジエチルジブトキシシラン等、またはこれらの化合物を含む高分子有機シラン化合物類が挙げられ、これらの１種または２種以上を用いることができる。
【００６５】
有機シラン化合物はモノマー（Ｅ−２）の合成に利用できるが、モノマー（Ｅ−１）を用いて合成したポリマーの反応性シリル基に有機シラン化合物を反応させてポリマー変性のために使用することもできる。いずれにおいても、反応性に優れ、紫外線遮蔽層を硬くする作用に優れている点で、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、ジメチルジメトキシシラン、ジメチルジエトキシシランが好ましい。
【００６６】
上記反応性シリル基を有するモノマー（Ｅ−１）と有機シラン化合物の反応に際しては、反応性シリル基含有モノマー（Ｅ−２）の側鎖に導入したい−Ｏ−Ｓｉ結合の数によって有機シラン化合物の量を調整する。例えば、平均５つの−Ｏ−Ｓｉ結合を導入したい場合は、モノマー（Ｅ−１）１モルに対し、有機シラン化合物が５モルとなるように反応させることが好ましい。ここで、（Ｅ−１）と有機シラン化合物との合計を１００モル％とした場合に、（Ｅ−１）が３０モル％を超えると、得られるモノマー（Ｅ−２）中に重合性二重結合が多数導入されることとなり、モノマー混合物（Ｉ）または(II)を重合する際にゲル化しやすくなる。（Ｅ−１）が０．１モル％よりも少ないと、（Ｅ−２）の中に重合性二重結合が導入されなくなる場合があるため、好ましくない。（Ｅ−２）中の好ましい二重結合量は、１分子当たり１〜４個の範囲である。
【００６７】
両者の反応は、（Ｅ−１）と有機シラン化合物とを混合することにより行う。必要によりメタノールや水等の溶媒を用いるとよい。加水分解縮合反応の進行に応じてアルコールが生成するので、このアルコールを留去しながら５０〜１００℃で１０分から５時間程度反応させるとよい。高温下で、あるいは長時間反応を行うと、（Ｅ−２）の重合が起きるおそれがある。なお、圧力は、０．１３Ｐａ〜１．０ＭＰａ程度とするのが好ましい。
【００６８】
また、加水分解縮合反応の速度を高めるには触媒を用いることが好ましく、分離の容易な固体触媒が好適である。固体触媒としては、「アンバーリスト１５」、「アンバーライト１５」、「アンバーライト２００Ｃ」（いずれも商品名；ローム・アンド・ハース社製）等の陽イオン交換樹脂が好ましいものとして挙げられる。触媒の使用量は特に限定されないが、（Ｅ−１）と有機シラン化合物との合計量に対して０．１〜２０質量％が好ましい。これらの合成反応に関しては、特許第２７２１１０６号にさらに詳細に記載されている。また、モノマー（Ｅ−１）を用いて合成したポリマーの反応性シリル基に対して有機シラン化合物を反応させてポリマー変性を行う場合も、上記反応条件を参考に適宜行えばよい。
【００６９】
以上が、モノマー混合物（Ｉ）およびモノマー混合物(II)として用いることのできるモノマーである。なお、モノマー混合物（Ｉ）およびモノマー混合物(II)では、必要に応じて用いられる各モノマー（Ｄ）〜（Ｅ）を適宜１種または２種以上選択することができ、これらはモノマー混合物（Ｉ）と(II)において、共通していても異なっていてもよい。
【００７０】
モノマー混合物（Ｉ）において用いることのできる各モノマーの好ましい量は、以下の通りである。なお、下記の量範囲は、使用するモノマーの合計量が１００質量％になるように選択する場合の各モノマーの好ましい使用量の目安である。
【００７１】
紫外線吸収性基を有するモノマー（Ａ）；０．１質量％以上（より好ましくは３質量％以上）、６０質量％以下（より好ましくは４０質量％以下）、
炭素数４以上のアルキル基を有するモノマー（Ｂ）；３質量％以上（より好ましくは５質量％以上）、９０質量％以下（より好ましくは８０質量％以下）、
紫外線安定性基を有するモノマー（Ｃ）；０．１質量％以上（より好ましくは０．５質量％以上）、２０質量％以下（より好ましくは１０質量％以下）、
その他のモノマー（Ｄ）；適宜調整、
反応性シリル基含有モノマー（Ｅ）；５０質量％以下（より好ましくは３０質量％以下）。
【００７２】
モノマー混合物(II)において用いることのできる各モノマーの好ましい量も、モノマー混合物（Ｉ）の場合のモノマー（Ｂ）〜（Ｅ）の好ましい量と同じである。
【００７３】
次に本発明の樹脂組成物を製造する方法を説明する。まず樹脂組成物の主成分となるポリマーを、前記したモノマー混合物（Ｉ）または(II)を重合することで合成する。
【００７４】
重合方法には格別の制限はなく、公知の重合法、例えば溶液重合法、分散重合法、懸濁重合法、乳化重合法等を使用できる。溶液重合法では、得られた反応生成物をそのままあるいは希釈するだけで、樹脂組成物を得ることができるため、好ましい重合法である。溶液重合の際に用いる溶媒としては、トルエン、キシレン、その他の芳香族系溶媒；ｎ−ブチルアルコール、プロピレングリコールメチルエーテル、ダイアセトンアルコール、エチルセロソルブ等のアルコール系溶媒；酢酸ブチル、酢酸エチル、セロソルブアセテート等のエステル系溶媒；メチルエチルケトン、メチルイソブチルケトン、シクロヘキサノン等のケトン系溶媒；ジメチルホルムアミド等を使用できる。使用する溶媒の種類はこれらに限定されるものではない。これらの溶媒は１種のみを使用してもよいし、２種以上を混合溶媒として使用してもよく、溶媒の使用量は、モノマー濃度、ポリマーの所望の分子量、ポリマー溶液濃度等を考慮し適宜定めればよい。
【００７５】
またモノマー混合物（Ｉ）または(II)を重合させる際には、重合開始剤が通常使用される。重合開始剤としては、例えば、２，２'−アゾビス−（２−メチルブチロニトリル）、ｔｅｒｔ−ブチルパーオキシ−２−エチルヘキサノエート、２，２'−アゾビスイソブチロニトリル、ベンゾイルパーオキサイド、ジ−ｔｅｒｔ−ブチルパーオキサイド等の公知のラジカル重合開始剤が使用可能である。重合開始剤の使用量は、ポリマーの要求特性等に応じて適宜決定すべきものであり、特に限定はないが、モノマー混合物（Ｉ）または(II)の全量に対し０．０１質量%以上、５０質量％以下が好ましく、より好ましくは０．０５質量%以上、２０質量％以下である。
【００７６】
また必要に応じて、例えば、ｎ−ドデシルメルカプタン、ｎ−ブチルメルカプタン、３−メルカプトプロピルメチルジメトキシシラン、（ＣＨ₃Ｏ）₃Ｓｉ−Ｓ−Ｓ−Ｓｉ（ＯＣＨ₃）₃のような連鎖移動剤を１種以上添加し、ポリマーの分子量を調整してもよい。
【００７７】
重合反応の温度も特に限定されないが、室温〜２００℃の範囲が好ましく、４０〜１４０℃がより好ましい。なお反応時間は、用いるモノマー成分の組成や重合開始剤の種類等に応じて、重合反応が効率よく完結し得るように適宜設定すればよい。
【００７８】
ポリマーの分子量も特に限定されないが、重量平均分子量（Ｍｗ）で２，０００〜５００，０００が好ましく、より好ましくは４，０００〜２５０，０００の範囲である。ここでいう重量平均分子量とは、ＧＰＣを用いて標準ポリスチレンを基準として求めた値を意味する。
【００７９】
第１のタイプの樹脂組成物は、モノマー成分（Ｉ）から得られたポリマーを含有するものであるが、塗工の際の作業性等の観点からは、溶媒でポリマーを溶解させた溶液状態であることが好ましい。溶媒としては、前記溶液重合の際に例示した溶媒がいずれも使用可能である。溶液重合以外の方法でポリマーを合成した場合は、重合後、ポリマーを分取して溶媒に溶解させればよい。
【００８０】
第２のタイプの樹脂組成物を得るには、モノマー成分(II)から得られたポリマーと、添加型紫外線吸収剤を混合すればよい。添加型紫外線吸収剤としては、例えば市販品の「チヌビン２３４」、「チヌビン３２９」（いずれもチバ・スペシャルティ・ケミカルズ社製）、「アデカスタブＬＡ−３６」、「アデカスタブＬＡ−３１」（いずれも旭電化工業社製）等が挙げられる。これらの紫外線吸収剤は、ベンゾトリアゾール等の紫外線吸収性基を有しており、紫外線を吸収する能力を有しているが、紫外線吸収性基の分解によってその紫外線吸収能が次第に失なわれる。しかし、本発明では、モノマー（Ｂ）および／または（Ｃ）を用いたポリマーが紫外線吸収性基の分解を抑制するため、紫外線吸収能が非常に長期間に亘って発揮される。紫外線吸収剤の好ましい配合量は、ポリマー（不揮発分）１００質量部に対して０．１〜３０質量部の範囲である。０．１質量部未満では紫外線遮蔽能が不充分となるおそれがあり、３０質量部を超えて過度に添加するとブリードアウトし易くなるため好ましくない。なお、酸化亜鉛等の無機系紫外線吸収剤を使用することもできる。
【００８１】
本発明の樹脂組成物（以下の説明では第１および第２のタイプの樹脂組成物を単に樹脂組成物で代表する）には、種々の添加剤が含まれていてもよい。以下、添加剤として好適に使用できる化合物を説明する。
【００８２】
シランカップリング剤
特に、太陽電池の基材がガラスの場合には、シランカップリング剤の添加によって、紫外線遮蔽層とガラス基材の密着性が向上する。シランカップリング剤として好適に使用できるのは、日本ユニカー社製の「Ａ−１８６」や「Ａ−１８７」、東レ・ダウコーニング・シリコーン社製の「ＳＨ６０４０」等のエポキシ基含有シランカップリング剤；日本ユニカー社製の「Ａ−１１２０」、東レ・ダウコーニング・シリコーン社製の「ＳＨ６０２０」、「ＳＨ６０２０Ｆ」、「ＳＺ６０２３」等のアミノ基含有シランカップリング剤；日本ユニカー社製の「Ａ−１３１０」、「Ｙ−５１８７」、「Ｙ−９９１０」、「Ａ−１１５９７」等である。これらは、ポリマー（不揮発分）１００質量部に対し０．５〜３０質量部の範囲で使用するとよい。
【００８３】
硬化剤
前記した架橋性モノマー（Ｄ−２）を含むモノマー混合物（Ｉ）または(II)からポリマーを得た場合には、そのモノマー（Ｄ−２）の官能基と反応し得る官能基を有する硬化剤（架橋剤）を樹脂組成物に添加して、塗膜化の際に架橋反応を行わせることが好ましく、これにより紫外線遮蔽層の各種特性が向上する。モノマー（Ｄ−２）の官能基に応じて公知の各種硬化剤が使用可能である。これら硬化剤の使用量は特に限定されず、用いられるモノマー（Ｄ−２）の量に応じて、適宜増減すればよい。
【００８４】
モノマー（Ｄ−２）の官能基がヒドロキシル基の場合には、イソシアネート基を２個以上有するポリイソシアネート化合物またはその変性物やアミノプラスト樹脂が、硬化剤として好ましい。
【００８５】
ポリイソシアネート化合物の具体例としては、トリレンジイソシアネート（ＴＤＩ）、４，４’−ジフェニルメタンジイソシアネート（ＭＤＩ）等の公知のジイソシアネート化合物；「スミジュールＮ」（住友バイエルウレタン社製）等のビュレットポリイソシアネート化合物；「デスモジュールＩＬ」、「デスモジュールＨＬ」（いずれもバイエルＡ．Ｇ．社製）、「コロネートＥＨ」（日本ポリウレタン工業社製）等として知られるイソシアヌレート環を有するポリイソシアネート化合物；「スミジュールＬ」（住友バイエルウレタン社製）等のアダクトポリイソシアネート化合物；「コロネートＬ」および「コロネートＬ−５５Ｅ」（いずれも日本ポリウレタン社製）等のアダクトポリイソシアネート化合物等を挙げることができる。これらは、単独で使用し得るほか、２種以上を併用することもできる。また、これらの化合物のイソシアネート基を活性水素を有するマスク剤と反応させて不活性化したいわゆるブロックイソシアネートも使用可能である。
【００８６】
アミノプラスト樹脂としては、メチルエーテル化メラミン樹脂、ブチルエーテル化メラミン樹脂、ブチルエーテル化ベンゾグアナミン系樹脂、ブチルエーテル化シクロヘキシルベンゾグアナミン系樹脂等およびこれらの水溶化物が挙げられる。
【００８７】
紫外線安定剤
前記した紫外線安定性基を有するモノマー（Ｃ）を用いずにポリマーを合成した場合には、添加型の紫外線安定剤を用いることもできる。添加型の紫外線安定剤として好ましいのは、立体障害ピペリジン化合物であり、例えば市販品としては、「チヌビン１２３」、「チヌビン１４４」、「チヌビン７６５」（いずれもチバ・スペシャルティ・ケミカルズ社製）、「アデカスタブＬＡ−５２」、「アデカスタブＬＡ−５７」、「アデカスタブＬＡ−６２」、「アデカスタブＬＡ−７７」（いずれも旭電化工業社製）等が挙げられる。また、これらの比較的低分子量の紫外線安定剤はブリードアウトの可能性があるため、前記した紫外線安定性基を有するモノマー（Ｃ）から別途ポリマー型の紫外線安定剤を合成し、これを添加してもよい。紫外線安定剤の好ましい配合量は、ポリマー（不揮発分）１００質量部に対して０．１〜１５質量部の範囲である。０．１質量部未満では、添加効果が発揮されず、特にモノマー（Ｃ）を使用しない場合の紫外線吸収性基の光分解抑制作用が不充分となり、紫外線遮蔽能を長期的に維持できないことがあるが、１５質量部を超えて過度に添加するとブリードアウトし易くなったり、耐水性を低下させるため好ましくない。
【００８８】
その他の樹脂
樹脂組成物中には、本発明の目的を阻害しない範囲であれば、その他の樹脂を一部共存させてもよい。例えば、熱可塑性樹脂や樹脂自身の作用あるいは硬化剤（架橋剤）によって架橋硬化する熱硬化性樹脂が挙げられる。これら他の樹脂の種類や使用量は、紫外線遮蔽性樹脂積層体の用途や要求特性等に応じて適宜決定すればよい。その他の樹脂の具体例としては、塩化ビニル系樹脂、ポリエステル系樹脂、アクリル系樹脂、シリコーン系樹脂等の熱可塑性樹脂；ウレタン系樹脂、アミノプラスト系樹脂、シリコーン系樹脂、エポキシ系樹脂、アクリル系樹脂等の単独硬化型の熱・紫外線・電子線硬化性樹脂；ポリエステル系樹脂、アクリル系樹脂、エポキシ系樹脂等の硬化剤によって硬化する熱硬化性樹脂を挙げることができる。
【００８９】
その他の添加剤
塗料等の層形成用組成物に一般に使用されるレベリング剤、酸化防止剤、タルク等の充填剤、防錆剤、蛍光性増白剤、酸化防止剤、帯電防止剤、顔料、染料、増粘剤、コロイダルシリカ、アルミナゾル等の無機微粒子やポリメチルメタクリレート系のアクリル系微粒子等を添加してもよい。また、特開平７−１７８３３５号公報や同９−３０２２５７号公報に記載されているような無機微粒子の表面に有機ポリマーが固定された複合無機微粒子を添加することもできる。また、反応性シリル基含有モノマーを用いてポリマーを合成した際には、加水分解縮合を促進する公知の硬化触媒を添加してもよい。
【００９０】
本発明の樹脂組成物は、色素増感型太陽電池の光入射面側に紫外線遮蔽層を形成するために用いられる。色素増感型太陽電池の構造としては特に限定されない。一般的な色素増感型太陽電池は、光入射面から順に、第１基材、第１導電膜、色素が吸着した状態の金属酸化物系半導体電極（光電極）、電荷移動層（酸化還元対を有する電解質）、対向電極、第２導電膜、第２基材とから構成されている。なお、第１基材側および第２基材側の両方から光が入射するように構成された太陽電池であれば、両側に紫外線遮蔽層を形成する。
【００９１】
上記第１基材および第２基材としては、透明性に優れたガラスやプラスチックフィルムが好ましい。プラスチックフィルムの素材としては、ポリエチレンテレフタレート（ＰＥＴ）、ポリブチレンテレフタレート（ＰＢＴ）、ポリエチレンナフタレート（ＰＥＮ）等のポリエステル系フィルム；ポリ塩化ビニル、ポリ塩化ビニリデン、フッ化ビニル等のポリハロゲン化ビニル系フィルム；ポリエチレン、ポリプロピレン等のポリオレフィン系フィルム；トリアセチルセルロース等のセルロースエステル系フィルム；（メタ）アクリレート系フィルム；ポリ（エチレン−テトラフルオロエチレン）（ＥＴＥＦ）、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリクロロトリフルオロエチレン（ＰＣＴＦＥ）、ポリビニリデンフルオライド（ＰＶＤＦ）、ポリ（テトラフルオロエチレン−ヘキサフルオロプロピレン）（ＦＥＰ）等のフッ素樹脂系フィルム等が挙げられる。第１基材と第２基材は同種のものでも異種のものでも構わない。
【００９２】
第１導電膜と第２導電膜は、通常、蒸着法やスパッタリング法等の公知の方法で、上記第１・第２基材表面に、Ａｌ、Ｃｕ、Ｒｈ、Ａｇ、Ｉｎ、Ｐｔ、Ａｕ等の金属薄膜、ＩＴＯ（Ｉｎ−Ｓｎ複合酸化物）、ＦＴＯ（フッ素をドープした酸化スズ等の導電性金属酸化物の薄膜、あるいは炭素薄膜等を形成することにより得られる。第１導電膜からのみ太陽光を受光する太陽電池であれば、第１導電膜を透明性の高い膜、第２導電膜を透明性の低い膜とする構成を採用してもよい。
【００９３】
色素が吸着した状態の金属酸化物系半導体電極は、通常の色素増感型太陽電池に用いられる公知の半導体電極がいずれも採用できるが、多孔性の半導体層を形成すると共に半導体の孔に色素を吸着させたものが好ましい。
【００９４】
上記半導体電極に用いられる半導体としては、Ｔｉ、Ｖ、Ｆｅ、Ｚｎ、Ｓｒ、Ｙ、Ｚｒ、Ｎｂ、Ｉｎ、Ｓｎ、Ｌａ、Ｃｅ、Ｈｆ、Ｔａ、またはＷの酸化物が好ましいものとして挙げられ、特に、ＴｉＯ₂、Ｆｅ₂Ｏ₃、ＺｎＯ、Ｎｂ₂Ｏ₅、ＷＯ₃が好ましい。また、金属酸化物に限られず、ＳｉやＧｅ等の単体半導体、III−Ｖ系化合物半導体、酸化物以外の金属カルコゲナイド（金属の硫化物、セレン化物、テルル化物等）、ペロブスカイト構造を有する化合物等も利用可能である。
【００９５】
半導体層の作成方法も特に限定されないが、金属酸化物系半導体電極の場合は、多孔質化のために、金属酸化物の微粒子の分散液を上記第１基材に、スピンコート法等で塗布するか噴霧する等して、その後熱処理（焼成）する方法を採用することが好ましい。金属酸化物微粒子の分散液は、ゾル−ゲル法や、金属酸化物を機械的に微粒子化して分散媒に分散させる等の公知の方法が採用可能である。分散媒には、水、アルコール・トルエン等の各種有機溶媒、これらの混合溶媒を用いればよい。
【００９６】
半導体層を形成した後、色素を吸着させる。色素を吸着させるには、色素を上記有機溶媒に溶解させて色素溶液を作製し、半導体層を浸漬するか、半導体層に噴霧・塗布すればよい。色素としては、可視光領域および赤外光領域の光を吸収する特性を有する従来公知の色素がいずれも採用でき、代表的なルテニウムビピリジン系色素（ルテニウム錯体）が最も好ましく、その他、シアニン系色素、スチリル系色素、ポルフィリン系色素等も使用可能である。
【００９７】
電荷移動層（酸化還元対を有する電解質）としては、通常、電解液を用いることができるが、電解液をポリマーマトリックスに含浸させたいわゆるゲル電解質や、酸化還元対を有する溶融塩も使用可能である。電解液は、電解質、溶媒および必要に応じて添加される添加剤とから構成される。電解液は、所定位置にそのまま注入して用いる以外に、貫通孔を有する多孔質支持体に充填して使用することもできる。
【００９８】
電解液の電解質は、酸化体と還元体とを組み合わせたもの（酸化還元対）であり、ヨウ素（Ｉ₂）と、金属ヨウ化物や第４級アンモニウム化合物ヨウ素塩等のヨウ化物との組合せや、臭素（Ｂｒ₂）と、金属臭化物や第４級アンモニウム化合物臭素塩等の臭化物との組合せが一般的である。
【００９９】
電解液の溶媒は、電解質を溶解し得ると共に、低粘度で、イオン伝導性を有するものであればよく、エーテル、アルコール、カーボネート、エステル化合物、ニトリル化合物等が使用可能である。
【０１００】
対向電極には公知の対向電極がいずれも使用でき特に限定されないが、エネルギー交換効率が高まるため、Ｐｔ微粒子を蒸着法やスパッタリング法等で層状化したものを用いるのが一般的である。
【０１０１】
本発明の紫外線遮蔽層は、太陽電池の光入射面側に位置する上記第１基材表面に、直接または必要に応じて接着改善層（プライマー層等）等の他の層を介して形成することができる。なお、第１基材側と第２基材側いずれからも受光できる構造の太陽電池であれば、両側に紫外線遮蔽層を設ける必要がある。
【０１０２】
樹脂組成物から得られる乾燥塗膜（紫外線遮蔽層）１００質量％中には、モノマー混合物（Ｉ）または(II)から得られたポリマー（変性ポリマーも含む。以下同じ）と添加型紫外線吸収剤（第２のタイプの場合）の合計が５０質量％以上、好ましくは８０質量％以上、より好ましくは９０質量％以上となるように、前記した各種添加剤の量を規制することが望ましい。５０質量％未満では紫外線遮蔽能塗膜の耐候性が不充分となるおそれがある。
【０１０３】
樹脂組成物を基材に塗布する方法としては、浸漬、吹き付け、刷毛塗り、カーテンフローコート、グラビアコート、ロールコート、スピンコート、バーコート、静電塗装等の公知の塗工方法がいずれも採用可能である。
【０１０４】
紫外線遮蔽層の厚さは、Ｌａｍｂｅｒｔ−Ｂｅｅｒの法則により、層中に存在する紫外線吸収性基の量、第１のタイプの樹脂組成物を用いる場合にはモノマー混合物（Ｉ）中の紫外線吸収性基を有するモノマー（Ａ）の使用量、第２のタイプの樹脂組成物を用いる場合には添加型紫外線吸収剤の使用量に依存する。従って、樹脂組成物に含まれる紫外線吸収性基の量と、色素増感型太陽電池の紫外線遮蔽層に要求される耐候性を勘案して、層の厚さを決定すればよい。通常、０．５〜１００μｍの範囲内である。厚さが１００μｍを超えると、紫外線吸収性能が飽和してコスト的に無駄である。逆に厚さが０．５μｍ未満では、基材上へ均一に塗工するのが困難であり、紫外線遮蔽能も不充分になるおそれがある。より好ましい厚さの範囲は１〜５０μｍ、さらに好ましくは２〜３０μｍである。
【０１０５】
紫外線遮蔽層の最表面には、耐汚染性向上のための光触媒機能層や、防曇層、熱線遮蔽層等を形成しても構わない。また、耐擦傷性向上のためのシリコーン系やアクリル系の硬化性樹脂によるハードコート層を形成する場合は、紫外線遮蔽層を形成するポリマーとして、反応性シリル基含有モノマー（Ｅ）を用いて得られたポリマーを使用することが好ましい。
【０１０６】
【実施例】
以下、実施例および比較例によって本発明をより詳細に説明するが、本発明はこれらに限定されるわけではなく、前・後記の趣旨に適合し得る範囲で適当に変更して実施することも可能であり、それらはいずれも本発明の技術的範囲に包含される。なお下記実施例および比較例において、「部」および「％」とあるのは、質量部または質量％を表す。
【０１０７】
合成例１（第２のタイプの樹脂組成物用ポリマーの合成）
攪拌機、滴下口、温度計、冷却管および窒素ガス導入口を備えたフラスコに、酢酸ブチル１００部を仕込んだ。別途、ｔｅｒｔ−ブチルメタクリレート７０部、メチルメタクリレート３０部、酢酸ブチル１０部および開始剤として２，２’−アゾビス（２−メチルブチロニトリル）０．６部を溶解させたモノマー溶液混合物を作製しておき、そのうちの３０％をフラスコにさらに仕込み、窒素ガスを導入して攪拌しながら８５℃に昇温した。残り７０％のモノマー溶液混合物を２時間かけて滴下し、滴下後さらに３時間加熱した。滴下後５時間後に９５℃に昇温し、そのまま２時間加熱を続けた後、冷却した。
【０１０８】
酢酸ブチル４０部で希釈したところ、不揮発分濃度が４０．１％のポリマー溶液Ｎｏ．１を得た。このポリマーの重量平均分子量（Ｍｗ）は４９２００であった。なお各合成例において、不揮発分濃度は、ポリマー溶液１ｇを秤量し、２００℃で１５分加熱乾燥させて測定した値であり、重量平均分子量はＧＰＣを用いて標準ポリスチレンを基準として求めた値である。
【０１０９】
合成例２、８、９
表１に示した合成例２、８、９については、モノマー組成を表１に示したように変えた以外は合成例１と同様にしてポリマー溶液Ｎｏ．２、８、９を得た。Ｎｏ．２は、第２のタイプの樹脂組成物用ポリマー溶液である。
【０１１０】
合成例３（第１のタイプの樹脂組成物用ポリマーの合成）
攪拌機、滴下口、温度計、冷却管および窒素ガス導入口を備えたフラスコに、酢酸エチル２５部と２−［２’−ヒドロキシ−５’−（メタクリロイルオキシエチル）フェニル］−２Ｈ−ベンゾトリアゾール（大塚化学社製、商品名「ＲＵＶＡ９３」；ＵＶＡ▲１▼と称する。）１０部を仕込んだ。別途、シクロヘキシルメタクリレート３０部、２−エチルヘキシルアクリレート１０部、ＵＶＡ▲１▼１０部、２−ヒドロキシエチルメタクリレート１５部、メチルメタクリレート２５部、酢酸エチル７５部および２，２’−アゾビス（２−メチルブチロニトリル）６部を溶解させたモノマー溶液混合物を作製しておき、そのうちの３０％をフラスコに仕込み、窒素ガスを導入して攪拌しながら還流温度まで昇温させた。残り７０％のモノマー溶液混合物を２時間かけて滴下し、滴下後さらに６時間加熱を続けた後、冷却した。酢酸エチル５０部で希釈したところ、不揮発分濃度が４０％のポリマー溶液が得られた。このポリマーの質量平均分子量は２１３００であった。
【０１１１】
合成例４〜７
表１に示した合成例４〜７については、モノマー組成を表１に示したように変えた以外は合成例３と同様にしてポリマー溶液Ｎｏ．４〜７を得た。これらはいずれも第１のタイプの樹脂組成物用ポリマー溶液である。
【０１１２】
【表１】

【０１１３】
なお、表１中の略語は、下記の意味である。
紫外線吸収性モノマー（Ａ）：紫外線吸収性基を有するモノマー（Ａ）
ＵＶＡ▲１▼：２−［２’−ヒドロキシ−５’−（メタクリロイルオキシエチル）フェニル］−２Ｈ−ベンゾトリアゾール（大塚化学社製；商品名「ＲＵＶＡ９３」）
ＵＶＡ▲２▼：２−ヒドロキシ−４−（２−アクリロイルオキシエトキシ）ベンゾフェノン（大阪有機化学工業社製；商品名「ＢＰ−１Ａ」）
ＵＶＡ▲３▼：２，４−ジフェニル−６−［２−ヒドロキシ−４−（２−アクリロイルオキシエトキシ）−ｓ−トリアジン
モノマー（Ｂ）：炭素数４以上のアルキル基を有するモノマー（Ｂ）
ＴＢＭＡ：ｔｅｒｔ−ブチルメタクリレート
ＣＨＭＡ：シクロヘキシルメタクリレート
２ＥＨＡ：２−エチルヘキシルアクリレート
紫外線安定性モノマー（Ｃ）：紫外線安定性基を有するモノマー（Ｃ）
ＨＡＬＳ▲１▼：「アデカスタブＬＡ８２」（商品名；旭電化工業社製）
（メタ）アクリレート（Ｄ−１）：炭素数３以下のアルキル基を有する（メタ）アクリレート（Ｄ−１）
ＭＭＡ：メチルメタクリレート
架橋性モノマー（Ｄ−２）：架橋性官能基を有するモノマー（Ｄ−２）
ＨＥＭＡ：２−ヒドロキシエチルメタクリレート
シリル基含有モノマー（Ｅ−１）：末端の反応性シリル基が炭素原子に直結しているモノマー（Ｅ−１）
「ＫＢＭ５０３」：（商品名；信越化学工業社製）
【０１１４】
実験例１
合成例１で得られたポリマー溶液Ｎｏ．１の１００部に、添加型紫外線吸収剤（商品名「アデカスタブＬＡ３１」；旭電化社製；ＬＡ３１と略す。）２部と、シランカップリング剤（商品名「Ａ１８６」；日本ユニカー社製）を２部配合し、トルエンで適当な粘度に希釈した。得られた樹脂組成物を、厚さ２ｍｍの石英ガラス板の片面に、バーコーターで乾燥膜厚が２０μｍとなるように塗工し、１００℃で３０分間乾燥させた。紫外線遮蔽層が石英ガラス板の片面に形成されたガラス積層体を得た。
【０１１５】
実験例２
硬化剤としてポリイソシアネート（商品名「スミジュールＮ３２００」；住友バイエルウレタン社製；Ｎ３２００と略す。）を９部添加した以外は実験例１と同様にして、ガラス積層体を作製した。
【０１１６】
実験例３〜４、６〜８
各ポリマー溶液１００部に、硬化剤「Ｎ３２００」を９部添加し、トルエンで適当な粘度に希釈した。得られた樹脂組成物を、厚さ１００μｍのポリエチレンテレフタレートフィルム（商品名「コスモシャインＡ４１００」；東洋紡績社製；ＰＥＴ）の片面に、バーコーターで乾燥膜厚が５μｍとなるように塗工し、８０℃で１２０分間乾燥させた。紫外線遮蔽層がＰＥＴフィルムの片面に形成されたＰＥＴ積層体を得た。
【０１１７】
実験例５
硬化剤「Ｎ３２００」ではなく、γ−（２−アミノエチル）アミノプロピルメチルジメトキシシラン；商品名「ＳＺ６０２３」；東レ・ダウコーニング・シリコーン社製）を４部添加した以外は実験例３と同様にしてＰＥＴ積層体を得た。
【０１１８】
実験例９
合成例９で得られたポリマー溶液Ｎｏ．９を用いた以外は実験例１と同様にしてガラス積層体を得た。
【０１１９】
以上の各実験例で得られた各積層体を以下の評価方法で評価し、結果を表２に示した。
【０１２０】
［ＵＶ遮蔽能保持率］
島津製作所社製の分光光度計（「ＵＶ−３１００」）を使用して、ブランクとして、紫外線遮蔽層を形成していない基材（ガラス、ＰＥＴ）の紫外線透過率を測定した後に、各積層体の３６０ｎｍにおける紫外線透過率を測定し、１００−紫外線透過率（％）を初期のＵＶカット率とした。
【０１２１】
また、各積層体試験片を、固定式メタルハライドランプ型促進耐候性試験機であるスガ試験機社製の超エネルギー照射試験機「ＵＥ−ＩＤＥＣ型」（インナーフィルターとして石英、アウターフィルターとして＃２７５を使用）に、紫外線入射側が紫外線遮蔽層となるようにセットした。［７０℃、７０％ＲＨの環境下、１００ｍＷ／ｃｍ²の紫外線を６時間照射］→［８０℃、９０％ＲＨの環境下で６時間照射］を１サイクルとし、３０サイクル繰り返した。
【０１２２】
上記分光光度計で促進試験後の３６０ｎｍにおける紫外線透過率を測定し、初期のＵＶカット率をＸ、３０サイクル後のＵＶカット率をＹとしたときに、［（Ｘ−Ｙ）／Ｘ］×１００（％）によって求められる値をＵＶ遮蔽能保持率（％）とした。
【０１２３】
［ヘイズ］
分光側色色差計（「ＳＺ−Σ９０」；日本電色工業社製）を用いて測定した。ブランクとして、紫外線遮蔽層を形成していない基材（ガラス、ＰＥＴ）のヘイズを測定してから、促進試験前のヘイズと、上記促進試験３０サイクル後のヘイズを測定した。
【０１２４】
［エネルギー変換効率の維持率］
色素増感型太陽電池を以下の手順で作製した。
【０１２５】
第１基材と第１導電膜として、ＦＴＯ基板（ＦＴＯ薄膜付ガラス：品番「ＶＺ０１９」；日本板硝子製）を用い、チタニアゾル（石原産業（株）、ＳＴＳ−２１）をスピンコートした後、１００℃で５分間加熱乾燥し、４５０℃で１時間熱処理を施して、第１導電膜側に膜厚２μｍの多孔質酸化チタン薄膜光電極を形成した。次に濃度３．０×１０^-4ＭのＲｕＮ３色素（Ruthenium 535、SOLARONIX社製）エタノール溶液に１０時間浸漬し、ＲｕＮ３色素を多孔質酸化チタン薄膜光電極に吸着させた。第１基材＋第１導電膜＋色素が吸着された光電極からなるパーツ▲１▼が得られた。
【０１２６】
前記実験例で得た各積層体（初期または促進耐候性試験３０サイクル後）を、上記パーツ▲１▼の第１基材（ガラス面側）の上に、紫外線遮蔽層が光入射側になるように置き、色素分解促進試験のために、３６５ｎｍの紫外光（ＨＢ−２５１０３ＢＹ−Ｃ、ウシオ製、光強度；３４ｍＷ／ｃｍ²）を３０分間照射した。
【０１２７】
別途、第２基材（製造工程２）と第２導電膜として、もう１枚のＦＴＯ基板を用い、Ｐｔを日立製スパッタリング装置「Ｅ−１０１０」で１０分×３回の条件でスパッタリングし、対向電極（白金電極）＋第２伝導膜＋第２基材からなるパーツ▲２▼を作製した。
【０１２８】
上記パーツ▲１▼と▲２▼を、ビーズの絶縁性スペーサーを介して約１０μｍの間隔を保って重ね合わせ、アセトニトリルを溶媒として０．１ｍｏｌ／ｌのヨウ化リチウム、０．０５ｍｏｌ／ｌのヨウ素、０．３ｍｏｌ／ｌの１，２−ジメチル−３−プロピルイミダゾールヨウ素塩、０．５ｍｏｌ／ｌのｔｅｒｔ−ブチルピリジンからなる電解液を注入した後に、エポキシ系接着剤で密封し、色素増感型太陽電池を作製した。
【０１２９】
続いて、第１基材（ＦＴＯ基板）と対向電極（白金電極）（光電変換面積：０．１９６ｃｍ²、φ５．０ｍｍ）にそれぞれワニ口クリップを接続し、５００Ｗのキセノンランプ（ウシオ社製）の光を、模擬太陽光として分光フィルター（Ｏｒｉｅｌ社製、ＡＭ１．５）を通して、紫外線遮蔽層側から照射した。このときの光強度Ｉは１００ｍＷ／ｃｍ²とした。
【０１３０】
発生した電気を電流電圧測定装置として電流計（「４８７」；ＫＥＩＴＨＬＥＹ社製）、ファンクションジェネレーター（「ＨＢ−１０５」；北斗電工社製）、ポテンシオスタット（ＨＡ−５０１６「北斗電工社製」）を使用して測定した。これより求められた開放光電圧Ｖｏｃ（Ｖ）、短絡光電流密度Ｊｓｃ（ｍＡ／ｃｍ²）、フィルファクターＦＦと、光強度Ｉ：１００ｍＷ／ｃｍ²から、下式によりエネルギー変換効率η（％）を求めた。
【０１３１】
η＝１００×Ｖｏｃ×Ｊｓｃ×ＦＦ／Ｉ
ここで、促進試験３０サイクルを行う前の積層体を使用したパーツ▲１▼を用いた場合を初期のエネルギー変換効率η₀とし、促進試験を３０サイクル行った積層体を使用したパーツ▲１▼を用いた場合を促進試験後のエネルギー変換効率η₁としたときの１００×（η₁／η₀）をエネルギー変換効率の維持率（％）とし、この値で、色素の分解を抑制できたかを評価した。
【０１３２】
【表２】

【０１３３】
表２から明らかなように、添加型紫外線吸収剤を用いる第２のタイプの紫外線遮蔽層が形成されている場合（実験例１〜２）は、紫外線吸収性モノマー（Ａ）を共重合している第１のタイプ（実験例３〜７）に比べ、ＵＶ遮蔽能保持率や、促進耐候性試験３０サイクル後の塗膜外観、エネルギー変換効率の維持率が若干低いレベルに留まり、全体として本発明例は優れた性能を示し、長期間に亘って紫外線遮蔽能を持続することが確認できた。
【０１３４】
紫外線吸収性モノマー（Ａ）を用いているが、モノマー（Ｂ）、（Ｃ）のいずれも用いられていない実験例８では、促進耐候性試験後の各性能が極端に低下していることから、紫外線吸収性基の光分解が起こっていることが裏付けられた。また、添加型紫外線吸収剤を用いているが、モノマー（Ｂ）、（Ｃ）のいずれも用いられていない実験例９では、促進耐候性試験によって「曇り」が生じ、このためＵＶ遮蔽能保持率自体は１００％であったが、ヘイズの低下が著しいことから、太陽電池としてのエネルギー変換効率の測定を中止した。
【０１３５】
【発明の効果】
本発明の色素増感型太陽電池は、特定の構造の紫外線遮蔽層を色素増感型太陽電池の入射光側に形成したので、長期間太陽光に曝露しても紫外線遮蔽能を高いレベルで保持することができ、太陽電池としてのエネルギー変換効率を高く維持することができた。従って、耐久性に優れた色素増感型太陽電池を提供することができた。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dye-sensitized solar cell provided with an ultraviolet shielding layer, and relates to a dye-sensitized solar cell capable of maintaining a high electromotive force without damaging ultraviolet shielding ability even after long-term use. It is.
[0002]
[Prior art]
A solar battery is a battery that can receive light such as sunlight and directly convert the energy into electric energy, and is a type of photoelectric conversion element that uses the photovoltaic effect. In addition to amorphous silicon solar cells, there are dye-sensitized solar cells that have recently attracted attention.
[0003]
This dye-sensitized solar cell is formed by using a metal oxide semiconductor as a photoelectrode and sandwiching an electrolyte having a redox pair with a counter electrode. Since the energy conversion efficiency has been remarkably increased by adsorbing the dye on the surface, further studies have been conducted for full-scale practical application.
[0004]
One of the problems to be investigated in dye-sensitized solar cells is the problem of extending the life and ensuring the durability. For example, titanium dioxide, which is frequently used as a metal oxide semiconductor, has a photocatalytic action that is excited by light (especially ultraviolet rays) and decomposes organic substances. Therefore, the dye adsorbed on the surface of titanium dioxide has this action. It is a problem that the energy conversion efficiency is gradually lowered due to the decomposition by gradually.
[0005]
In order to solve the above problem, a proposal has been made to include a UV absorber in a constituent member such as a solar cell module (Japanese Patent Laid-Open No. Sho 62-273780). However, this prior art still has room for improvement in terms of ensuring the durability of the dye-sensitized solar cell because the absorption capacity of the ultraviolet absorber decreases with time.
[0006]
[Problems to be solved by the invention]
Therefore, in the present invention, an ultraviolet ray shielding layer that can maintain high energy conversion efficiency even when exposed to sunlight for a long period of time is found, and an object is to improve the durability of the dye-sensitized solar cell. .
[0007]
[Means for Solving the Problems]
A first type of the dye-sensitized solar cell according to the present invention is a dye-sensitized solar cell in which an ultraviolet shielding layer is formed on the light incident surface side, and the ultraviolet shielding layer is an ultraviolet absorbing group. A resin composition for forming an ultraviolet shielding layer, which comprises a polymer synthesized from a monomer mixture (I) comprising a monomer having an alkyl group and a monomer having an alkyl group having 4 or more carbon atoms and / or a monomer having an ultraviolet light-stable group It is formed.
[0008]
When the monomer mixture (I) contains a monomer having an alkyl group having 4 or more carbon atoms or a monomer having a UV-stable group, the UV-absorbing group of the monomer having a UV-absorbing group can be reduced by ultraviolet rays or the like. Since the decomposition could be prevented over a long period of time, it succeeded in enhancing the durability of the dye-sensitized solar cell. Moreover, in this 1st type, since an ultraviolet absorptive group can be integrated in a polymer chain, a ultraviolet-ray shielding ability is a high level over a long period of time compared with the 2nd type using an addition type ultraviolet absorber. Can be maintained.
[0009]
A second type of the dye-sensitized solar cell according to the present invention is a dye-sensitized solar cell in which an ultraviolet shielding layer is formed on the light incident surface side, and the ultraviolet shielding layer has 4 or more carbon atoms. Formed from a resin composition for forming an ultraviolet shielding layer, which comprises a polymer synthesized from a monomer mixture (II) containing a monomer having an alkyl group and / or a monomer having an ultraviolet-stable group, and an additive-type ultraviolet absorber. It is characterized by that.
[0010]
Since the monomer mixture (II) also contains a monomer having an alkyl group having 4 or more carbon atoms or a monomer having an ultraviolet-stable group, the ultraviolet absorber is prevented from being decomposed by ultraviolet rays or the like for a long period of time. It was possible to improve the durability of the dye-sensitized solar cell.
[0011]
The monomer mixture (I) or (II) may further contain a monomer having a crosslinkable functional group. If a crosslinker is used, the chemical resistance and water resistance of the ultraviolet shielding layer can be improved. it can.
[0012]
In the case where the substrate for the photoelectrode of the dye-sensitized solar cell is made of glass and the ultraviolet shielding layer is directly formed on the glass substrate, the resin composition for forming the ultraviolet shielding layer is further a silane coupling agent. It is preferable that the material contains a glass substrate and the adhesion between the ultraviolet light shielding layer is further improved.
[0013]
Of course, the photoelectrode substrate of the dye-sensitized solar cell may be made of plastic, and the dye-sensitized solar cell having a configuration in which the ultraviolet shielding layer is formed directly or indirectly on the plastic substrate is also provided. It is included in the scope of the present invention.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
As a result of examining the ultraviolet absorbing ability of organic ultraviolet absorbers, the present inventors have found that an ultraviolet absorbing group having the ability to absorb ultraviolet rays is decomposed by being exposed to ultraviolet rays for a long period of time. I found out that it would lose absorption. And as a result of further investigation, the reason is not clear by using a monomer having an alkyl group having 4 or more carbon atoms or a monomer having a UV-stable group, but the decomposition of the UV-absorbing group can be suppressed as much as possible, The present inventors have found that a high level of ultraviolet absorption ability can be maintained over a long period of time, and have reached the present invention. Hereinafter, the present invention will be described in detail. In the present invention, “monomer” means a radical polymerizable monomer, and “polymer” means not only a homopolymer but also a copolymer or a ternary or higher copolymer.
[0015]
In the first type of dye-sensitized solar cell of the present invention, a polymer synthesized from the monomer mixture (I) is a main component of the resin composition for forming an ultraviolet shielding layer. In this monomer mixture (I), a monomer (A) having an ultraviolet absorbing group, a monomer (B) having an alkyl group having 4 or more carbon atoms and / or a monomer (C) having an ultraviolet stabilizing group are essential. Is included. In addition, the second type of dye-sensitized solar cell is a monomer mixture (II) containing, as an essential component, a monomer (B) having an alkyl group having 4 or more carbon atoms and / or a monomer (C) having a UV-stable group. The ultraviolet shielding layer is formed from a resin composition for forming an ultraviolet shielding layer containing a polymer synthesized from (1) and an additive type ultraviolet absorber. Hereinafter, each raw material will be described.
[0016]
(A) Monomer having ultraviolet absorbing group
As the monomer (A) having a UV-absorbing group, all monomers having a radical polymerizable double bond and a UV-absorbing group in the molecule can be used, but the following general ones are particularly preferably used in the present invention. It is at least one selected from monomers represented by the formulas (A-1) to (A-3), and by using these monomers as a copolymerization component, ultraviolet absorption ability is imparted to the resulting polymer. . That is, even when the obtained coating film is irradiated with ultraviolet rays, the shielding layer absorbs the ultraviolet rays, so that it is possible to suppress the dye decomposition by the metal oxide semiconductor located below the shielding layer. Compared with the second type using an additive type ultraviolet absorber, there is almost no bleeding out of the ultraviolet absorber, so that the durability of the ultraviolet shielding performance is improved.
[0017]
[Chemical 1]

[0018]
(Wherein R¹Represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R²Represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and R^ThreeIs a linear or branched alkylene group having 1 to 12 carbon atoms or —O—R ′ — (R ′ is a linear or branched alkylene group having 2 or 3 carbon atoms. ) And R^FourRepresents a hydrogen atom or a methyl group), a benzotriazole monomer (A-1).
[0019]
[Chemical formula 2]

[0020]
(Wherein R¹, R^FourRepresents the same meaning as above, R^FiveRepresents a hydrogen atom or a hydroxyl group, R⁶Represents a hydrogen atom or a C1-C6 alkoxy group, R⁷Represents a linear or branched alkylene group having 1 to 12 carbon atoms. The benzophenone monomer (A-2) represented by this.
[0021]
[Chemical 3]

[0022]
(Where R^FourRepresents the same meaning as above, R⁸Is a direct bond,-(CH₂CH₂O)_p-Or -CH₂CH (OH) -CH₂O- represents, and p represents an integer of 1 to 5. R⁹, R^Ten, R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶Each independently represents a hydrogen atom, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group or an alkyl group. ) Triazine monomer (A-3) represented by
[0023]
Preferable specific examples of the monomer (A-1) include, for example, 2- [2′-hydroxy-5 ′-(meth) acryloyloxymethylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5′- (Meth) acryloyloxyethylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(meth) acryloyloxypropylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5′- (Meth) acryloyloxyhexylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-tert-butyl-5 ′-(meth) acryloyloxyethylphenyl] -2H-benzotriazole, 2- [2 '-Hydroxy-5'-(β- (meth) acryloyloxyethoxy) -3'-tert-butylphenyl]- 5-tert-butyl-2H-benzotriazole and the like.
[0024]
Specific examples of the monomer (A-2) include 2-hydroxy-4- [2- (meth) acryloyloxy] ethoxybenzophenone, 2-hydroxy-4- [2- (meth) acryloyloxy] butoxybenzophenone, 2, 2′-dihydroxy-4- [2- (meth) acryloyloxy] ethoxybenzophenone, 2-hydroxy-4- [2- (meth) acryloyloxy] ethoxy-4 ′-(2-hydroxyethoxy) benzophenone, 2-hydroxy -3-tert-butyl-4- [2- (meth) acryloyloxy] ethoxybenzophenone, 2-hydroxy-3-tert-butyl-4- [2- (meth) acryloyloxy] butoxybenzophenone, and the like. .
[0025]
Specific examples of the monomer (A-3) include 2,4-diphenyl-6- [2-hydroxy-4- (2-acryloyloxyethoxy)]-s-triazine, 2,4-bis (2-methyl). Phenyl) -6- [2-hydroxy-4- (2-acryloyloxyethoxy)]-s-triazine, 2,4-bis (2-methoxyphenyl) -6- [2-hydroxy-4- (2-acryloyl) Oxyethoxy)]-s-triazine and the like.
[0026]
In addition, when using the monomer (A-1) and / or the monomer (A-2), if an alkali metal or a basic compound having a strong basicity coexists in the ultraviolet shielding layer, the problem of coloring of the ultraviolet shielding layer or over time will occur. In view of suppressing these, the R in each general formula tends to cause a significant decrease in ultraviolet absorption performance.¹It is particularly preferable to use a monomer which is an alkyl group having 4 to 8 carbon atoms at the 3-position which is adjacent to the OH group.
[0027]
The monomers (A-1) to (A-3) having the ultraviolet absorbing group have ultraviolet absorption characteristics specific to the compound, and therefore can be used alone depending on the required ultraviolet shielding performance. It is preferable to use a combination of species or more as appropriate.
[0028]
Various metal oxide semiconductors have inherent degradation wavelengths. For example, titanium dioxide absorbs ultraviolet rays of 410 nm or less, and all wavelengths cause photocatalysis, so triazine monomer (A-3) is used. It is preferable to use each of the benzophenone monomer (A-2) and the benzotriazole monomer (A-1) alone, rather than using them alone. Most preferable is a two-type combination pattern of the monomer (A-1) or (A-2) and the monomer (A-3).
[0029]
In addition, the monomer obtained by polymerizing each of the monomers (A-1) to (A-3) having the UV-absorbing group alone or copolymerizing two or more kinds alone or in combination of two or more kinds. May be contained in the resin composition for forming an ultraviolet shielding layer.
[0030]
The monomer mixture (I) must contain one or both of the monomer (B) having an alkyl group having 4 or more carbon atoms and the monomer (C) having an ultraviolet light-stable group. These are because the UV absorbing group of the monomer (A) having the UV absorbing group described above or the UV absorbing group of the additive type UV absorber to be described later is gradually photodegraded by prolonged UV exposure. Has the effect of preventing.
[0031]
(B) Monomer having an alkyl group having 4 or more carbon atoms
As this monomer (B), specifically, a (meth) acrylate monomer represented by the following general formula is preferably used.
[0032]
[Formula 4]

[0033]
(Wherein R¹⁷Represents a hydrogen atom or a methyl group, and X represents a hydrocarbon group having 4 or more carbon atoms).
[0034]
In the above formula, the substituent represented by X is an alicyclic hydrocarbon group having 4 or more carbon atoms such as cyclohexyl group, methylcyclohexyl group, cyclododecyl group; butyl group, isobutyl group, tert-butyl group, 2- A linear or branched alkyl group having 4 or more carbon atoms, such as ethylhexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, pentadecyl group, octadecyl group; bornyl group, isobornyl group And a polycyclic hydrocarbon group having 4 or more carbon atoms such as alicyclic hydrocarbon group, branched alkyl group, and straight chain alkyl group having 6 or more carbon atoms.
[0035]
More specific examples of the monomer (B) include, for example, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, isobutyl (meth) acrylate, tert Non-limiting examples include butyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, stearyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and one or more of these may be used. Can be used.
[0036]
(C) Monomer having UV-stable group
When the monomer (C) having a UV-stable group is copolymerized, in addition to the effect of suppressing the photodecomposition of the UV-absorbing group described above, UV-stability is imparted to the UV-shielding layer, and the shielding effect is further enhanced. . The monomer (C) having a UV-stable group is not particularly limited as long as it has a radically polymerizable double bond and a UV-stable group in the molecule at the same time. It is a monomer represented by the formula (C-1) or (C-2).
[0037]
[Chemical formula 5]

[0038]
(Wherein R¹⁸Represents a hydrogen atom or a cyano group, R¹⁹, R²⁰Each independently represents a hydrogen atom or a methyl group;^{twenty one}Represents a hydrogen atom or a hydrocarbon group, and Y represents an oxygen atom or an imino group. )
[0039]
[Chemical 6]

[0040]
(Wherein R^{twenty two}Represents a hydrogen atom or a cyano group, R^{twenty three}, R^{twenty four}, R^{twenty five}, R²⁶Each independently represents a hydrogen atom or a methyl group, and Z represents an oxygen atom or an imino group. ).
[0041]
Specific examples of the monomer (C-1) include 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6-tetra. Methylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano -4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6 , 6-Tetramethylpiperidine and the like are mentioned without limitation, and these may be used alone or in combination of two or more as necessary.
[0042]
Specific examples of the monomer (C-2) include 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano. Non-limiting examples include -4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine and the like. These may be used alone or in combination of two or more as necessary.
[0043]
The monomer mixture (I) used for synthesizing the polymer as the main component of the first ultraviolet shielding layer forming resin composition of the present invention includes the monomer (A) having the ultraviolet absorbing group described above and In addition, a monomer (B) having an alkyl group having 4 or more carbon atoms and / or a monomer (C) having a UV-stable group are included as essential monomers. On the other hand, in the monomer mixture (II) used in the second type of the present invention, the monomer (B) having an alkyl group having 4 or more carbon atoms and / or the monomer (C) having a UV-stable group are essential components. is there. In the second type of resin composition, since an additive type ultraviolet absorber described later is blended as an essential component, it is not necessary to use the monomer (A) having an ultraviolet absorbing group as an essential monomer. However, the monomer mixture (II) may contain the monomer (A).
[0044]
In the monomer mixture (I) or the monomer mixture (II), in addition to the above essential monomers, the following various monomers may be used in combination as necessary for appropriately changing the physical properties of the ultraviolet shielding layer.
[0045]
(D) Other monomers
Specific examples of the other monomer (D) include (meth) acrylate (referred to as D-1) having an alkyl group having 3 or less carbon atoms such as methyl (meth) acrylate and ethyl (meth) acrylate. It is done. These monomers (D-1) are excellent in copolymerization with the above-described monomers (A) to (C), are hard, have a role of forming a shielding layer excellent in water resistance and mechanical strength, and are inexpensive. Easy to use. Among them, methyl methacrylate having a high homopolymer Tg is particularly preferable.
[0046]
Alternatively, the ultraviolet shielding layer may be crosslinked by synthesizing a polymer using a monomer (D-2) having a crosslinkable functional group and blending a curing agent (crosslinking agent) separately. Specific examples of the monomer (D-2) having a crosslinkable functional group include monomers having a carboxyl group such as (meth) acrylic acid, itaconic acid and maleic anhydride; 2- (meth) acryloyloxyethyl acid phosphate, etc. Acid phosphate ester monomers; glycidyl (meth) acrylate, methylglycidyl (meth) acrylate, alicyclic epoxy group-containing (meth) acrylate (for example, manufactured by Daicel Chemical Industries, Ltd .; trade name “CYCLOMER M-100”), etc. Epoxy group-containing (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxyl-terminated flexible (meth) acrylate (for example, manufactured by Daicel Chemical Industries, Ltd .; trade name “Placcel FM” )) And other active hydrogen (hydroxyl) groups Monomers which can be used. Among these, it is preferable to use a hydroxyl group-containing monomer and to contain a polyisocyanate as a curing agent in the resin composition for an ultraviolet shielding layer and to crosslink the ultraviolet shielding layer by a reaction between the hydroxyl group and the isocyanate group.
[0047]
In addition, as other monomers, nitrogen-containing monomers such as (meth) acrylamide, imide (meth) acrylate, N-methylol (meth) acrylamide; and two polymerizable double bonds such as ethylene glycol di (meth) acrylate Monomers; halogen-containing monomers such as vinyl chloride; aromatic monomers such as styrene and α-methylstyrene; vinyl ethers and the like can also be used.
[0048]
(E) Reactive silyl group-containing monomer
The monomer mixture (I) or (II) may contain a reactive silyl group-containing monomer (referred to as monomer (E) for convenience). The monomer (E) acts as a crosslinkable functional group-containing monomer, and when a polymer synthesized using the monomer is used for the ultraviolet shielding layer, for example, the substrate of the solar cell is glass, and the ultraviolet shielding layer is directly glass. In the case of forming on a substrate, the adhesion between the glass substrate and the ultraviolet shielding layer is increased, which is a preferred embodiment.
[0049]
The reactive silyl group-containing monomer (E) is a monomer having a reactive silyl group at least at a terminal and a polymerizable double bond. The terminal reactive silyl group is directly connected to the carbon atom in the monomer (E-1) and the terminal reactive silyl group is via a polysiloxane bond that may have a substituent. Can be divided into types (E-2) linked to carbon atoms in the monomer, and any of them can be used. A monomer (E-2) is obtained by making an organosilane compound react with a monomer (E-1). Normal polysiloxane bond is -SiH₂-O-SiH₂Although it is -O-, the polysiloxane bond in the monomer (E-2) may have a substituent. That is, any one or more hydrogen atoms bonded to Si may be substituted with an alkoxy (alkyloxy) group having 1 to 6 carbon atoms or an alkyl group having 1 to 10 carbon atoms. Of course, each substituent may be the same or different. If an alkoxy group exists as a substituent, a reactive silyl group also exists in the polysiloxane bond portion. In addition, a reactive silyl group means a hydrolyzable silyl group, and means all functional groups that can generate a silanol (Si—OH) group by a hydrolysis reaction.
[0050]
The monomer (E-1) having a reactive silyl group directly bonded to a carbon atom has a polymerizable double bond and a reactive silyl group directly bonded to a carbon atom. Specific examples are shown by the following general formulas (E-1-1) to (E-1-3).
[0051]
[Chemical 7]

[0052]
(Wherein R²⁷Represents a hydrogen atom or a methyl group, R²⁸Represents a hydrocarbon group having 1 to 6 carbon atoms, a represents an integer of 1 to 5, and b represents 0 or 1.
[0053]
[Chemical 8]

[0054]
(Wherein R²⁹Is R²⁸Represents the same meaning or an alkyloxyalkyl group, and c represents 0 or 1)
[0055]
[Chemical 9]

[0056]
(Wherein R³⁰Is R²⁸And d represents 0 or 1).
[0057]
The monomer (E-1-1) is a monomer having a hydrolyzable alkoxysilyl group and a (meth) acryloyl group, and in each general formula, a hydrocarbon group having 1 to 6 carbon atoms is a methyl group Alkyl group such as ethyl group and propyl group; alkenyl group such as vinyl group, isopropenyl group and allyl group; and aryl group such as phenyl group.
[0058]
Specific examples of the monomer (E-1-1) include 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropyltributoxysilane, 3- (meth) acryloxypropyltriisopropenoxysilane, (meth) acryloxymethyltrimethoxysilane, (meth) acryloxymethyltriethoxysilane, (meth) acryloxymethyltributoxysilane, and the like.
[0059]
Considering ease of handling, reactivity, crosslink density, etc., 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxytriethoxysilane, 3- (meth) acryloxypropyl are particularly preferable. Methyldimethoxysilane. Further, in terms of copolymerizability with the monomers (A) to (C), it has a (meth) acryloyl group rather than vinyl-functional monomers (E-1-2) and (E-1-3) (E -1-1) is preferred.
[0060]
The monomer (E-1-2) is a vinyl functional monomer having a vinyl group and a hydrolyzable alkoxysilyl group, and the monomer (E-1-3) is a vinyl functional alkoxysilane compound.
[0061]
Examples of the monomer (E-1-2) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, and the like (monomer (E-1-3)). Examples thereof include 3-vinyloxypropyltrimethoxysilane, 3-vinyloxypropyltriethoxysilane, 3-vinyloxypropylmethyldimethoxysilane, and the like. Among these, vinyltrimethoxysilane, vinyltriethoxysilane, 3-vinyloxypropyltrimethoxysilane, and the like are preferable from the viewpoint of easy handling and reactivity.
[0062]
By reacting the organosilane compound with the monomer (E-1) having a reactive silyl group directly bonded to the carbon atom, the terminal reactive silyl group is converted to a carbon atom in the monomer via the polysiloxane bond. A monomer (E-2) having a bonded structure is obtained. The organosilane compound that can be used is an organosilane compound represented by the following general formula and / or a hydrolysis condensate thereof.
[0063]
R³¹ _mSi (OR³²)_n                      ... (E)
(Wherein R³¹May be the same or different and each represents a hydrogen atom, a lower alkyl group, an aryl group, a vinyl group, a mercapto group directly connected to a carbon chain, or a methacryloyl group;³²May be the same or different and each represents a hydrogen atom, a lower alkyl group or an acyl group, m is 0 or a positive integer, n is an integer of 1 or more, and m + n corresponds to the valence of Si)
[0064]
Specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltrimethoxysilane Ethoxysilane, ethyltriisopropoxysilane, ethyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiisopropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldiisopropoxysilane, diethyl Examples include dibutoxysilane and the like, and high-molecular organic silane compounds containing these compounds, and one or more of these can be used.
[0065]
The organosilane compound can be used for the synthesis of the monomer (E-2), but the organosilane compound is reacted with the reactive silyl group of the polymer synthesized using the monomer (E-1) and used for polymer modification. You can also. In any case, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane are excellent in reactivity and excellent in the effect of hardening the ultraviolet shielding layer. preferable.
[0066]
In the reaction of the monomer (E-1) having a reactive silyl group and the organic silane compound, the organic silane compound depends on the number of —O—Si bonds to be introduced into the side chain of the reactive silyl group-containing monomer (E-2). Adjust the amount. For example, when it is desired to introduce an average of five —O—Si bonds, it is preferable to cause the organosilane compound to be 5 moles per mole of the monomer (E-1). Here, when the total of (E-1) and the organosilane compound is 100 mol%, when (E-1) exceeds 30 mol%, the polymerizable monomer (E-2) has two polymerizable groups. A large number of heavy bonds are introduced, and the monomer mixture (I) or (II) is easily gelled when polymerized. When (E-1) is less than 0.1 mol%, a polymerizable double bond may not be introduced into (E-2), which is not preferable. A preferable double bond amount in (E-2) is in the range of 1 to 4 per molecule.
[0067]
Both reactions are performed by mixing (E-1) and an organosilane compound. If necessary, a solvent such as methanol or water may be used. Since alcohol is produced as the hydrolysis condensation reaction proceeds, the reaction may be carried out at 50 to 100 ° C. for 10 minutes to 5 hours while distilling off the alcohol. When the reaction is performed at a high temperature or for a long time, polymerization of (E-2) may occur. The pressure is preferably about 0.13 Pa to 1.0 MPa.
[0068]
In order to increase the rate of hydrolysis condensation reaction, it is preferable to use a catalyst, and a solid catalyst that is easily separated is suitable. Preferred examples of the solid catalyst include cation exchange resins such as “Amberlist 15”, “Amberlite 15”, “Amberlite 200C” (all trade names: manufactured by Rohm and Haas). Although the usage-amount of a catalyst is not specifically limited, 0.1-20 mass% is preferable with respect to the total amount of (E-1) and an organosilane compound. These synthetic reactions are described in more detail in Japanese Patent No. 2721106. In addition, when the polymer is modified by reacting an organic silane compound with the reactive silyl group of the polymer synthesized using the monomer (E-1), it may be appropriately performed with reference to the above reaction conditions.
[0069]
These are the monomers that can be used as the monomer mixture (I) and the monomer mixture (II). In the monomer mixture (I) and the monomer mixture (II), one or more monomers (D) to (E) to be used can be appropriately selected as necessary. ) And (II) may be the same or different.
[0070]
Preferred amounts of each monomer that can be used in the monomer mixture (I) are as follows. In addition, the following amount range is a standard of the preferable usage amount of each monomer when selecting so that the total amount of the monomer to be used may be 100 mass%.
[0071]
Monomer (A) having an ultraviolet absorbing group: 0.1% by mass or more (more preferably 3% by mass or more), 60% by mass or less (more preferably 40% by mass or less),
Monomer (B) having an alkyl group having 4 or more carbon atoms; 3 mass% or more (more preferably 5 mass% or more), 90 mass% or less (more preferably 80 mass% or less),
Monomer (C) having a UV-stable group: 0.1% by mass or more (more preferably 0.5% by mass or more), 20% by mass or less (more preferably 10% by mass or less),
Other monomer (D); appropriately adjusted,
Reactive silyl group-containing monomer (E); 50% by mass or less (more preferably 30% by mass or less).
[0072]
The preferable amount of each monomer that can be used in the monomer mixture (II) is also the same as the preferable amount of the monomers (B) to (E) in the case of the monomer mixture (I).
[0073]
Next, a method for producing the resin composition of the present invention will be described. First, a polymer as a main component of the resin composition is synthesized by polymerizing the monomer mixture (I) or (II).
[0074]
The polymerization method is not particularly limited, and known polymerization methods such as solution polymerization method, dispersion polymerization method, suspension polymerization method, emulsion polymerization method and the like can be used. The solution polymerization method is a preferable polymerization method because a resin composition can be obtained by directly or diluting the obtained reaction product. Solvents used for solution polymerization include toluene, xylene, and other aromatic solvents; alcohol solvents such as n-butyl alcohol, propylene glycol methyl ether, diacetone alcohol, ethyl cellosolve; butyl acetate, ethyl acetate, cellosolve Ester solvents such as acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; dimethylformamide and the like can be used. The kind of solvent to be used is not limited to these. These solvents may be used alone, or two or more may be used as a mixed solvent. The amount of solvent used is determined in consideration of the monomer concentration, the desired molecular weight of the polymer, the polymer solution concentration, and the like. What is necessary is just to determine suitably.
[0075]
Further, when the monomer mixture (I) or (II) is polymerized, a polymerization initiator is usually used. Examples of the polymerization initiator include 2,2′-azobis- (2-methylbutyronitrile), tert-butylperoxy-2-ethylhexanoate, 2,2′-azobisisobutyronitrile, benzoyl Known radical polymerization initiators such as peroxide and di-tert-butyl peroxide can be used. The amount of the polymerization initiator to be used should be appropriately determined according to the required characteristics of the polymer and the like, and is not particularly limited, but is 0.01% by mass or more based on the total amount of the monomer mixture (I) or (II), 50 It is preferably at most mass%, more preferably at least 0.05 mass% and at most 20 mass%.
[0076]
If necessary, for example, n-dodecyl mercaptan, n-butyl mercaptan, 3-mercaptopropylmethyldimethoxysilane, (CH_ThreeO)_ThreeSi-S-S-Si (OCH_Three)_ThreeOne or more chain transfer agents such as may be added to adjust the molecular weight of the polymer.
[0077]
The temperature of the polymerization reaction is not particularly limited, but is preferably in the range of room temperature to 200 ° C, more preferably 40 to 140 ° C. In addition, what is necessary is just to set reaction time suitably so that a polymerization reaction can be completed efficiently according to the composition of the monomer component to be used, the kind of polymerization initiator, etc.
[0078]
Although the molecular weight of the polymer is not particularly limited, the weight average molecular weight (Mw) is preferably 2,000 to 500,000, and more preferably 4,000 to 250,000. A weight average molecular weight here means the value calculated | required on the basis of standard polystyrene using GPC.
[0079]
The first type of resin composition contains a polymer obtained from the monomer component (I), but from the viewpoint of workability during coating, etc., a solution state in which the polymer is dissolved with a solvent. It is preferable that As the solvent, any of the solvents exemplified in the solution polymerization can be used. When the polymer is synthesized by a method other than solution polymerization, after polymerization, the polymer may be collected and dissolved in a solvent.
[0080]
In order to obtain the second type resin composition, a polymer obtained from the monomer component (II) and an additive type ultraviolet absorber may be mixed. Examples of additive type UV absorbers include commercially available products “Tinuvin 234” and “Tinubin 329” (both manufactured by Ciba Specialty Chemicals), “Adekastab LA-36”, “Adekastab LA-31” (both Asahi) Manufactured by Denka Kogyo Co., Ltd.). These ultraviolet absorbers have an ultraviolet absorbing group such as benzotriazole and have an ability to absorb ultraviolet rays, but the ultraviolet absorbing ability is gradually lost by the decomposition of the ultraviolet absorbing group. However, in the present invention, since the polymer using the monomer (B) and / or (C) suppresses the decomposition of the ultraviolet absorbing group, the ultraviolet absorbing ability is exhibited for a very long time. The preferable compounding quantity of a ultraviolet absorber is the range of 0.1-30 mass parts with respect to 100 mass parts of polymers (nonvolatile content). If the amount is less than 0.1 parts by mass, the ultraviolet shielding ability may be insufficient, and if it exceeds 30 parts by mass, it tends to bleed out, which is not preferable. An inorganic ultraviolet absorber such as zinc oxide can also be used.
[0081]
Various additives may be included in the resin composition of the present invention (in the following description, the first and second types of resin compositions are simply represented by the resin composition). Hereinafter, compounds that can be suitably used as additives will be described.
[0082]
Silane coupling agent
In particular, when the solar cell substrate is glass, the adhesion between the ultraviolet shielding layer and the glass substrate is improved by the addition of the silane coupling agent. Epoxy group-containing silane coupling agents such as “A-186” and “A-187” manufactured by Nihon Unicar Co., Ltd. and “SH6040” manufactured by Toray Dow Corning Silicone Co., Ltd. can be suitably used as the silane coupling agent. Amino group-containing silane coupling agents such as “A-1120” manufactured by Nihon Unicar Co., Ltd., “SH6020”, “SH6020F”, “SZ6023” manufactured by Toray Dow Corning Silicone Co., Ltd .; 1310 "," Y-5187 "," Y-9910 "," A-11597 ", and the like. These are good to use in the range of 0.5-30 mass parts with respect to 100 mass parts of polymers (nonvolatile content).
[0083]
Hardener
A curing agent having a functional group capable of reacting with the functional group of the monomer (D-2) when the polymer is obtained from the monomer mixture (I) or (II) containing the crosslinkable monomer (D-2). (Crosslinking agent) is preferably added to the resin composition to cause a crosslinking reaction during coating, thereby improving various characteristics of the ultraviolet shielding layer. Various known curing agents can be used depending on the functional group of the monomer (D-2). The usage-amount of these hardening | curing agents is not specifically limited, According to the quantity of the monomer (D-2) used, what is necessary is just to increase / decrease suitably.
[0084]
When the functional group of the monomer (D-2) is a hydroxyl group, a polyisocyanate compound having two or more isocyanate groups, a modified product thereof, or an aminoplast resin is preferable as a curing agent.
[0085]
Specific examples of the polyisocyanate compound include known diisocyanate compounds such as tolylene diisocyanate (TDI) and 4,4′-diphenylmethane diisocyanate (MDI); bullet polyisocyanates such as “Sumijour N” (manufactured by Sumitomo Bayer Urethane Co., Ltd.) Compound: Polyisocyanate compound having an isocyanurate ring known as “Desmodur IL”, “Desmodur HL” (all manufactured by Bayer AG), “Coronate EH” (manufactured by Nippon Polyurethane Industry), etc .; Adduct polyisocyanate compounds such as “Sumijour L” (manufactured by Sumitomo Bayer Urethane Co., Ltd.); adduct polyisocyanate compounds such as “Coronate L” and “Coronate L-55E” (both manufactured by Nippon Polyurethane Co., Ltd.), and the like. These can be used alone or in combination of two or more. In addition, so-called blocked isocyanates in which the isocyanate groups of these compounds are inactivated by reacting with a masking agent having active hydrogen can also be used.
[0086]
Examples of aminoplast resins include methyl etherified melamine resins, butyl etherified melamine resins, butyl etherified benzoguanamine resins, butyl etherified cyclohexyl benzoguanamine resins, and water-soluble products thereof.
[0087]
UV stabilizer
When the polymer is synthesized without using the monomer (C) having the above-described ultraviolet-stable group, an additive-type ultraviolet stabilizer can also be used. Preferred as the additive type UV stabilizer is a sterically hindered piperidine compound. For example, commercially available products include “Tinuvin 123”, “Tinuvin 144”, “Tinuvin 765” (all manufactured by Ciba Specialty Chemicals), “ADK STAB LA-52”, “ADK STAB LA-57”, “ADK STAB LA-62”, “ADK STAB LA-77” (all manufactured by Asahi Denka Kogyo Co., Ltd.) and the like can be mentioned. In addition, since these relatively low molecular weight UV stabilizers may bleed out, a polymer type UV stabilizer is separately synthesized from the monomer (C) having the UV stabilizing group and added. May be. The preferable compounding quantity of a ultraviolet stabilizer is the range of 0.1-15 mass parts with respect to 100 mass parts of polymers (nonvolatile content). If the amount is less than 0.1 parts by mass, the effect of addition is not exhibited, and the action of suppressing the photodecomposition of the UV-absorbing group in particular when the monomer (C) is not used becomes insufficient, and the UV shielding ability cannot be maintained for a long time. However, excessive addition over 15 parts by mass is not preferable because it tends to bleed out or reduce water resistance.
[0088]
Other resins
In the resin composition, other resins may partially coexist as long as the object of the present invention is not impaired. For example, a thermoplastic resin or a thermosetting resin that is crosslinked and cured by the action of the resin itself or a curing agent (crosslinking agent) can be used. What is necessary is just to determine suitably the kind and usage-amount of these other resin according to the use, required characteristic, etc. of a ultraviolet-ray shielding resin laminated body. Specific examples of other resins include thermoplastic resins such as vinyl chloride resins, polyester resins, acrylic resins, and silicone resins; urethane resins, aminoplast resins, silicone resins, epoxy resins, and acrylic resins. Examples thereof include single-curing heat / ultraviolet / electron beam curable resins such as resins; thermosetting resins that are cured by a curing agent such as polyester resins, acrylic resins, and epoxy resins.
[0089]
Other additives
Leveling agents, antioxidants, fillers such as talc, etc., rust inhibitors, fluorescent brighteners, antioxidants, antistatic agents, pigments, dyes, thickeners commonly used in layer forming compositions such as paints Agents, inorganic fine particles such as colloidal silica and alumina sol, polymethyl methacrylate acrylic fine particles, and the like may be added. Further, composite inorganic fine particles in which an organic polymer is fixed to the surface of the inorganic fine particles as described in JP-A-7-178335 and 9-302257 can also be added. In addition, when a polymer is synthesized using a reactive silyl group-containing monomer, a known curing catalyst that promotes hydrolytic condensation may be added.
[0090]
The resin composition of the present invention is used for forming an ultraviolet shielding layer on the light incident surface side of a dye-sensitized solar cell. The structure of the dye-sensitized solar cell is not particularly limited. A general dye-sensitized solar cell includes, in order from a light incident surface, a first base material, a first conductive film, a metal oxide semiconductor electrode (photoelectrode) in which a dye is adsorbed, and a charge transfer layer (redox reduction). An electrolyte having a pair), a counter electrode, a second conductive film, and a second base material. In addition, if it is a solar cell comprised so that light may enter from both the 1st base material side and the 2nd base material side, an ultraviolet-ray shielding layer is formed in both sides.
[0091]
As said 1st base material and a 2nd base material, the glass and plastic film excellent in transparency are preferable. Plastic film materials include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN); polyvinyl halides such as polyvinyl chloride, polyvinylidene chloride, and vinyl fluoride Film; Polyolefin film such as polyethylene and polypropylene; Cellulose ester film such as triacetyl cellulose; (Meth) acrylate film; Poly (ethylene-tetrafluoroethylene) (ETEF), polytetrafluoroethylene (PTFE), polychloro Fluoropolymers such as trifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), poly (tetrafluoroethylene-hexafluoropropylene) (FEP) Irumu, and the like. The first substrate and the second substrate may be the same or different.
[0092]
The first conductive film and the second conductive film are usually formed on the surfaces of the first and second substrates by a known method such as vapor deposition or sputtering, and Al, Cu, Rh, Ag, In, Pt, Au, etc. It is obtained by forming a metal thin film, ITO (In-Sn complex oxide), FTO (fluorine-doped conductive metal oxide thin film such as tin oxide, or a carbon thin film only from the first conductive film. As long as the solar cell receives sunlight, a configuration in which the first conductive film is a highly transparent film and the second conductive film is a low-transparency film may be employed.
[0093]
As the metal oxide semiconductor electrode in which the dye is adsorbed, any of the known semiconductor electrodes used in ordinary dye-sensitized solar cells can be used. However, the porous semiconductor layer is formed and the dye is formed in the semiconductor pores. Those having adsorbed are preferred.
[0094]
Preferred examples of the semiconductor used for the semiconductor electrode include oxides of Ti, V, Fe, Zn, Sr, Y, Zr, Nb, In, Sn, La, Ce, Hf, Ta, or W. In particular, TiO₂, Fe₂O_Three, ZnO, Nb₂O_Five, WO_ThreeIs preferred. Also, not limited to metal oxides, simple semiconductors such as Si and Ge, III-V compound semiconductors, metal chalcogenides (metal sulfides, selenides, tellurides, etc.) other than oxides, compounds having a perovskite structure, etc. Is also available.
[0095]
The method of forming the semiconductor layer is not particularly limited, but in the case of a metal oxide semiconductor electrode, a dispersion of metal oxide fine particles is applied to the first substrate by spin coating or the like in order to make it porous. It is preferable to employ a method in which heat treatment (firing) is performed thereafter by spraying or spraying. For the dispersion of the metal oxide fine particles, a known method such as a sol-gel method or mechanically finely dividing the metal oxide into a dispersion medium can be employed. As the dispersion medium, water, various organic solvents such as alcohol / toluene, and mixed solvents thereof may be used.
[0096]
After forming the semiconductor layer, the dye is adsorbed. In order to adsorb the dye, the dye is dissolved in the organic solvent to prepare a dye solution, and the semiconductor layer is immersed or sprayed and applied to the semiconductor layer. As the dye, any conventionally known dye having the property of absorbing light in the visible light region and the infrared light region can be adopted, and a typical ruthenium bipyridine dye (ruthenium complex) is most preferable. In addition, a cyanine dye Also, styryl dyes, porphyrin dyes, and the like can be used.
[0097]
As the charge transfer layer (electrolyte having an oxidation-reduction pair), an electrolytic solution can usually be used, but a so-called gel electrolyte obtained by impregnating a polymer matrix with an electrolytic solution or a molten salt having an oxidation-reduction pair can also be used. is there. The electrolytic solution is composed of an electrolyte, a solvent, and an additive that is added as necessary. In addition to injecting and using the electrolytic solution as it is at a predetermined position, the electrolytic solution can also be used by filling a porous support having through holes.
[0098]
The electrolyte of the electrolytic solution is a combination of an oxidant and a reductant (a redox couple), and iodine (I₂) And iodides such as metal iodides and quaternary ammonium compound iodine salts, bromine (Br₂) And a bromide such as a metal bromide or a quaternary ammonium compound bromine salt is generally used.
[0099]
The solvent of the electrolytic solution is not particularly limited as long as it can dissolve the electrolyte, has low viscosity, and has ion conductivity, and ether, alcohol, carbonate, ester compound, nitrile compound, and the like can be used.
[0100]
Any known counter electrode can be used as the counter electrode, and the counter electrode is not particularly limited. However, in order to increase energy exchange efficiency, it is common to use Pt particles layered by vapor deposition or sputtering.
[0101]
The ultraviolet shielding layer of the present invention is formed on the surface of the first base material located on the light incident surface side of the solar cell, directly or as necessary via another layer such as an adhesion improving layer (primer layer or the like). be able to. In addition, if it is a solar cell of the structure which can receive light from both the 1st base material side and the 2nd base material side, it is necessary to provide an ultraviolet-ray shielding layer on both sides.
[0102]
In 100% by mass of the dried coating film (ultraviolet shielding layer) obtained from the resin composition, the polymer obtained from the monomer mixture (I) or (II) (including the modified polymer, the same shall apply hereinafter) and the additive type ultraviolet absorber It is desirable to regulate the amounts of the various additives described above so that the total (in the case of the second type) is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more. If it is less than 50% by mass, the weather resistance of the ultraviolet shielding coating film may be insufficient.
[0103]
As a method for applying the resin composition to the substrate, any known coating method such as dipping, spraying, brush coating, curtain flow coating, gravure coating, roll coating, spin coating, bar coating, electrostatic coating, etc. is adopted. Is possible.
[0104]
The thickness of the ultraviolet shielding layer is determined according to Lambert-Beer's law, the amount of the ultraviolet absorbing group present in the layer, and the ultraviolet absorbing property in the monomer mixture (I) when the first type resin composition is used. The amount of the monomer (A) having a group depends on the amount of the additive-type ultraviolet absorber when the second type resin composition is used. Therefore, the thickness of the layer may be determined in consideration of the amount of the ultraviolet absorbing group contained in the resin composition and the weather resistance required for the ultraviolet shielding layer of the dye-sensitized solar cell. Usually, it exists in the range of 0.5-100 micrometers. When the thickness exceeds 100 μm, the ultraviolet absorption performance is saturated, which is wasteful in cost. On the other hand, when the thickness is less than 0.5 μm, it is difficult to uniformly coat the substrate, and the ultraviolet shielding ability may be insufficient. A more preferable thickness range is 1 to 50 μm, and more preferably 2 to 30 μm.
[0105]
A photocatalytic functional layer for improving contamination resistance, an antifogging layer, a heat ray shielding layer, or the like may be formed on the outermost surface of the ultraviolet shielding layer. In addition, when forming a hard coat layer with a silicone-based or acrylic-based curable resin for improving the scratch resistance, a reactive silyl group-containing monomer (E) is used as a polymer for forming an ultraviolet shielding layer. It is preferred to use the polymer obtained.
[0106]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these examples, and may be implemented with appropriate modifications within a range that can meet the purpose described above and below. All of these are possible within the scope of the present invention. In the following examples and comparative examples, “parts” and “%” represent parts by mass or mass%.
[0107]
Synthesis Example 1 (Synthesis of polymer for second type resin composition)
100 parts of butyl acetate was charged into a flask equipped with a stirrer, a dripping port, a thermometer, a cooling pipe and a nitrogen gas inlet. Separately, a monomer solution mixture was prepared by dissolving 70 parts of tert-butyl methacrylate, 30 parts of methyl methacrylate, 10 parts of butyl acetate and 0.6 part of 2,2′-azobis (2-methylbutyronitrile) as an initiator. In addition, 30% of the mixture was further charged into the flask, and the temperature was raised to 85 ° C. while introducing nitrogen gas and stirring. The remaining 70% monomer solution mixture was added dropwise over 2 hours, followed by heating for 3 hours. Five hours after the dropping, the temperature was raised to 95 ° C., and heating was continued for 2 hours, followed by cooling.
[0108]
When diluted with 40 parts of butyl acetate, the polymer solution no. 1 was obtained. The weight average molecular weight (Mw) of this polymer was 49200. In each synthesis example, the non-volatile content concentration is a value measured by weighing 1 g of a polymer solution and heating and drying at 200 ° C. for 15 minutes, and the weight average molecular weight is a value obtained using GPC as a standard polystyrene. is there.
[0109]
Synthesis Examples 2, 8, and 9
For Synthesis Examples 2, 8, and 9 shown in Table 1, polymer solution No. 1 was prepared in the same manner as in Synthesis Example 1 except that the monomer composition was changed as shown in Table 1. 2, 8, 9 were obtained. No. 2 is a polymer solution for the second type of resin composition.
[0110]
Synthesis Example 3 (Synthesis of polymer for first type resin composition)
In a flask equipped with a stirrer, a dripping port, a thermometer, a condenser tube and a nitrogen gas inlet, 25 parts of ethyl acetate and 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl) phenyl] -2H-benzotriazole ( (Otsuka Chemical Co., Ltd., trade name “RUVA93”; referred to as UVA 1).) 10 parts were charged. Separately, 30 parts of cyclohexyl methacrylate, 10 parts of 2-ethylhexyl acrylate, 10 parts of UVA (1), 15 parts of 2-hydroxyethyl methacrylate, 25 parts of methyl methacrylate, 75 parts of ethyl acetate and 2,2′-azobis (2-methylbutyrate) A monomer solution mixture in which 6 parts (ronitrile) was dissolved was prepared, 30% of the mixture was charged into a flask, and nitrogen gas was introduced and the mixture was heated to reflux temperature while stirring. The remaining 70% monomer solution mixture was added dropwise over 2 hours. After the addition, the mixture was further heated for 6 hours and then cooled. When diluted with 50 parts of ethyl acetate, a polymer solution having a nonvolatile content of 40% was obtained. The polymer had a weight average molecular weight of 21,300.
[0111]
Synthesis Examples 4-7
For Synthesis Examples 4 to 7 shown in Table 1, polymer solution No. 1 was prepared in the same manner as in Synthesis Example 3 except that the monomer composition was changed as shown in Table 1. 4-7 were obtained. These are all polymer solutions for the first type of resin composition.
[0112]
[Table 1]

[0113]
In addition, the abbreviation in Table 1 has the following meaning.
UV-absorbing monomer (A): monomer having UV-absorbing group (A)
UVA (1): 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole (manufactured by Otsuka Chemical Co., Ltd .; trade name "RUVA93")
UVA (2): 2-hydroxy-4- (2-acryloyloxyethoxy) benzophenone (manufactured by Osaka Organic Chemical Industry; trade name “BP-1A”)
UVA (3): 2,4-diphenyl-6- [2-hydroxy-4- (2-acryloyloxyethoxy) -s-triazine
Monomer (B): Monomer (B) having an alkyl group having 4 or more carbon atoms
TBMA: tert-butyl methacrylate
CHMA: cyclohexyl methacrylate
2EHA: 2-ethylhexyl acrylate
UV-stable monomer (C): monomer having UV-stable group (C)
HALS (1): “ADK STAB LA82” (trade name; manufactured by Asahi Denka Kogyo Co., Ltd.)
(Meth) acrylate (D-1): (meth) acrylate (D-1) having an alkyl group having 3 or less carbon atoms
MMA: Methyl methacrylate
Crosslinkable monomer (D-2): Monomer having a crosslinkable functional group (D-2)
HEMA: 2-hydroxyethyl methacrylate
Silyl group-containing monomer (E-1): Monomer (E-1) in which a reactive silyl group at the terminal is directly bonded to a carbon atom
“KBM503”: (trade name; manufactured by Shin-Etsu Chemical Co., Ltd.)
[0114]
Experimental example 1
The polymer solution No. obtained in Synthesis Example 1 was used. 1 part 100 parts of additive type UV absorber (trade name “ADK STAB LA31”; manufactured by Asahi Denka Co .; abbreviated as LA31) and silane coupling agent (trade name “A186”; manufactured by Nihon Unicar Co., Ltd.) Two parts were mixed and diluted to an appropriate viscosity with toluene. The obtained resin composition was applied to one side of a 2 mm thick quartz glass plate with a bar coater so that the dry film thickness was 20 μm, and dried at 100 ° C. for 30 minutes. A glass laminate having an ultraviolet shielding layer formed on one side of a quartz glass plate was obtained.
[0115]
Experimental example 2
A glass laminate was prepared in the same manner as in Experimental Example 1, except that 9 parts of polyisocyanate (trade name “Sumijour N3200”; manufactured by Sumitomo Bayer Urethane Co., Ltd .; abbreviated as N3200) was added as a curing agent.
[0116]
Experimental Examples 3-4, 6-8
9 parts of the curing agent “N3200” was added to 100 parts of each polymer solution, and diluted to an appropriate viscosity with toluene. The obtained resin composition was applied to one side of a 100 μm thick polyethylene terephthalate film (trade name “Cosmo Shine A4100”; manufactured by Toyobo Co., Ltd .; PET) so that the dry film thickness was 5 μm with a bar coater. , And dried at 80 ° C. for 120 minutes. A PET laminate having an ultraviolet shielding layer formed on one side of the PET film was obtained.
[0117]
Experimental Example 5
Experimental Example 3 except that 4 parts of γ- (2-aminoethyl) aminopropylmethyldimethoxysilane; trade name “SZ6023” (manufactured by Toray Dow Corning Silicone) were added instead of the curing agent “N3200”. Thus, a PET laminate was obtained.
[0118]
Experimental Example 9
Polymer solution No. obtained in Synthesis Example 9 A glass laminate was obtained in the same manner as in Experimental Example 1 except that 9 was used.
[0119]
Each laminate obtained in each of the above experimental examples was evaluated by the following evaluation method, and the results are shown in Table 2.
[0120]
[UV shielding ability retention rate]
Using a spectrophotometer ("UV-3100") manufactured by Shimadzu Corporation, after measuring the ultraviolet transmittance of a substrate (glass, PET) on which no ultraviolet shielding layer was formed as a blank, each laminate The UV transmittance at 360 nm was measured, and 100-UV transmittance (%) was defined as the initial UV cut rate.
[0121]
In addition, each laminate test piece is a fixed metal halide lamp type accelerated weathering tester, a super energy irradiation tester “UE-IDEC type” manufactured by Suga Test Instruments Co., Ltd. (with quartz as an inner filter and # 275 as an outer filter). Used) was set so that the ultraviolet incident side would be an ultraviolet shielding layer. [100 mW / cm in an environment of 70 ° C. and 70% RH²Was irradiated for 6 hours] → [irradiated for 6 hours in an environment of 80 ° C. and 90% RH] as one cycle and repeated 30 cycles.
[0122]
[(X−Y) / X] × where the ultraviolet transmittance at 360 nm after the accelerated test was measured with the spectrophotometer, the initial UV cut rate was X, and the UV cut rate after 30 cycles was Y. The value obtained by 100 (%) was defined as the UV shielding ability retention rate (%).
[0123]
[Haze]
It measured using the spectroscopic side color difference meter ("SZ-Σ90"; Nippon Denshoku Industries Co., Ltd. make). As a blank, after measuring the haze of the base material (glass, PET) on which the ultraviolet shielding layer was not formed, the haze before the acceleration test and the haze after 30 cycles of the acceleration test were measured.
[0124]
[Maintenance rate of energy conversion efficiency]
A dye-sensitized solar cell was produced by the following procedure.
[0125]
As a 1st base material and a 1st electrically conductive film, after spin-coating titania sol (Ishihara Sangyo Co., Ltd., STS-21) using FTO board | substrate (GTO with FTO thin film: Product number "VZ019"; Nippon Sheet Glass make), it is 100. Heat drying at 5 ° C. for 5 minutes and heat treatment at 450 ° C. for 1 hour to form a porous titanium oxide thin film photoelectrode having a thickness of 2 μm on the first conductive film side. Next, the concentration is 3.0 × 10^-FourThe RuN3 dye (Ruthenium 535, manufactured by SOLARONIX) ethanol solution was immersed in an ethanol solution for 10 hours to adsorb the RuN3 dye on the porous titanium oxide thin film photoelectrode. A part {circle around (1)} comprising the first base material + the first conductive film + the photoelectrode on which the dye was adsorbed was obtained.
[0126]
Each laminated body obtained in the experimental example (after initial or accelerated weathering test 30 cycles) is placed on the first base material (glass surface side) of the part {circle around (1)} with the ultraviolet shielding layer on the light incident side. In order to promote the degradation of pigment, the ultraviolet light of 365 nm (HB-25103BY-C, manufactured by Ushio, light intensity; 34 mW / cm²) For 30 minutes.
[0127]
Separately, as the second base material (manufacturing process 2) and the second conductive film, another FTO substrate was used, and Pt was sputtered by Hitachi sputtering apparatus “E-1010” for 10 minutes × 3 times. A part {circle around (2)} composed of a counter electrode (platinum electrode) + second conductive film + second substrate was produced.
[0128]
The above parts (1) and (2) are overlapped with an insulating spacer of beads at an interval of about 10 μm, 0.1 mol / l lithium iodide and 0.05 mol / l iodine using acetonitrile as a solvent. , 0.3 mol / l of 1,2-dimethyl-3-propylimidazole iodine salt, 0.5 mol / l of tert-butylpyridine electrolyte was injected, sealed with an epoxy adhesive, and dye-sensitized. Type solar cells were produced.
[0129]
Subsequently, the first base material (FTO substrate) and the counter electrode (platinum electrode) (photoelectric conversion area: 0.196 cm)², Φ5.0mm), each with a crocodile clip, and irradiating the light from a 500W xenon lamp (USHIO Co., Ltd.) as simulated sunlight through the spectral filter (ORIE, AM1.5) from the UV shielding layer side. did. The light intensity I at this time is 100 mW / cm.²It was.
[0130]
The generated electricity is used as a current / voltage measuring device as an ammeter (“487”; manufactured by KEITHLEY), a function generator (“HB-105”; manufactured by Hokuto Denko), a potentiostat (HA-5016 “manufactured by Hokuto Denko”) Was measured using. The open-circuit photovoltage Voc (V) and the short-circuit photocurrent density Jsc (mA / cm) determined from this.²), Fill factor FF and light intensity I: 100 mW / cm²From this, the energy conversion efficiency η (%) was determined by the following equation.
[0131]
η = 100 × Voc × Jsc × FF / I
Here, the case where the part {circle around (1)} using the laminate before 30 cycles of the acceleration test is used is the initial energy conversion efficiency η₀The energy conversion efficiency η after the acceleration test is the case where the part (1) using the laminate subjected to the acceleration test for 30 cycles is used.₁100 × (η₁/ Η₀) Was defined as the maintenance rate (%) of energy conversion efficiency, and this value was used to evaluate whether the decomposition of the pigment could be suppressed.
[0132]
[Table 2]

[0133]
As is clear from Table 2, when the second type ultraviolet shielding layer using the additive type ultraviolet absorber is formed (Experimental Examples 1 and 2), the ultraviolet absorbing monomer (A) is copolymerized. Compared to the first type (Experimental Examples 3 to 7), the UV shielding ability retention rate, the coating appearance after 30 cycles of accelerated weathering test, and the maintenance rate of energy conversion efficiency remain at a slightly lower level. The inventive examples showed excellent performance, and it was confirmed that the ultraviolet shielding ability was maintained over a long period of time.
[0134]
In Experimental Example 8 where the ultraviolet absorbing monomer (A) is used but neither the monomer (B) nor (C) is used, each performance after the accelerated weather resistance test is extremely lowered. It was confirmed that the photodecomposition of the UV-absorbing group occurred. In addition, in Experimental Example 9 in which an additive type ultraviolet absorber was used but neither of the monomers (B) and (C) was used, “fogging” was generated by the accelerated weather resistance test, and thus the UV shielding ability was maintained. Although the rate itself was 100%, the measurement of the energy conversion efficiency as a solar cell was stopped because the haze was significantly reduced.
[0135]
【The invention's effect】
In the dye-sensitized solar cell of the present invention, the ultraviolet shielding layer having a specific structure is formed on the incident light side of the dye-sensitized solar cell, so that the ultraviolet shielding ability is high even when exposed to sunlight for a long time. The energy conversion efficiency as a solar cell could be maintained high. Therefore, the dye-sensitized solar cell excellent in durability could be provided.

Claims (16)

In a dye-sensitized solar cell in which an ultraviolet shielding layer is formed on the light incident surface side, the ultraviolet shielding layer includes a monomer having an ultraviolet absorbing group, a monomer having an alkyl group having 4 or more carbon atoms, and / or ultraviolet rays. Formed from a resin composition for forming an ultraviolet shielding layer containing a polymer synthesized from a monomer mixture (I) containing a monomer having a stability group ,
The monomer having the ultraviolet absorbing group is represented by the following general formulas (A-1) to (A-3).

Wherein R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R ² represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, cyano R ³ represents a linear or branched alkylene group having 1 to 12 carbon atoms or —O—R′— (R ′ is a linear or branched group having 2 or 3 carbon atoms). R ⁴ represents a hydrogen atom or a methyl group).

(Wherein, R ^1, R ⁴ are as defined above, R ⁵ represents a hydrogen atom or a hydroxyl group, R ⁶ represents a hydrogen atom or an alkoxy group having 1 to 6 carbon atoms, R ⁷ is C 1 -C -12 represents a linear or branched alkylene group.

(Wherein R ⁴ represents the same meaning as described above, R ⁸ represents a direct bond, — (CH ₂ CH ₂ O) p— or —CH ₂ CH (OH) —CH ₂ O—, and p represents 1 to Represents an integer of 5. R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are each independently a hydrogen atom, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group or an alkyl group. Represents a group.)
Is at least one selected from monomers represented by:
The monomer having an alkyl group having 4 or more carbon atoms is represented by the following general formula (B)

(In the formula, R ¹⁷ represents a hydrogen atom or a methyl group, and X represents a hydrocarbon group having 4 or more carbon atoms.)
A (meth) acrylate monomer represented by
The monomer having the UV-stable group is represented by the following general formula (C-1)

(Wherein R ¹⁸ represents a hydrogen atom or a cyano group, R ¹⁹ and R ²⁰ each independently represents a hydrogen atom or a methyl group, R ²¹ represents a hydrogen atom or a hydrocarbon group, and Y represents an oxygen atom or Represents an imino group),
And / or the following general formula (C-2)

(Wherein R ²² represents a hydrogen atom or a cyano group, R ²³ , R ²⁴ , R ²⁵ and R ²⁶ each independently represents a hydrogen atom or a methyl group, and Z represents an oxygen atom or an imino group.) A dye-sensitized solar cell, which is a monomer represented by In a dye-sensitized solar cell in which an ultraviolet shielding layer is formed on the light incident surface side, the ultraviolet shielding layer includes a monomer having an alkyl group having 4 or more carbon atoms and / or a monomer having an ultraviolet stability group Formed from a resin composition for forming an ultraviolet shielding layer containing a polymer synthesized from the mixture (II) and an additive type ultraviolet absorber ;
The monomer having an alkyl group having 4 or more carbon atoms is represented by the following general formula (B)

(In the formula, R ¹⁷ represents a hydrogen atom or a methyl group, and X represents a hydrocarbon group having 4 or more carbon atoms.)
A (meth) acrylate monomer represented by
The monomer having the UV-stable group is represented by the following general formula (C-1)

(Wherein R ¹⁸ represents a hydrogen atom or a cyano group, R ¹⁹ and R ²⁰ each independently represents a hydrogen atom or a methyl group, R ²¹ represents a hydrogen atom or a hydrocarbon group, and Y represents an oxygen atom or Represents an imino group),
And / or the following general formula (C-2)

(Wherein R ²² represents a hydrogen atom or a cyano group, R ²³ , R ²⁴ , R ²⁵ and R ²⁶ each independently represents a hydrogen atom or a methyl group, and Z represents an oxygen atom or an imino group.) A dye-sensitized solar cell, which is a monomer represented by   The dye-sensitized solar cell according to claim 1 or 2, wherein the monomer mixture (I) or (II) further contains a monomer having a crosslinkable functional group.   The dye-sensitized solar cell according to any one of claims 1 to 3, wherein the ultraviolet shielding layer is directly formed on the glass substrate of the dye-sensitized solar cell.   The dye-sensitized solar cell according to claim 4, wherein the resin composition for forming an ultraviolet shielding layer further contains a silane coupling agent.   The dye-sensitized solar cell according to any one of claims 1 to 3, wherein the ultraviolet shielding layer is formed directly or indirectly on the plastic substrate of the dye-sensitized solar cell. Containing a polymer synthesized from a monomer mixture (I) comprising a monomer having an ultraviolet absorbing group, a monomer having an alkyl group having 4 or more carbon atoms and / or a monomer having an ultraviolet stable group,
The monomer having the ultraviolet absorbing group is represented by the following general formulas (A-1) to (A-3).

(Wherein R ¹ Represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R ² Represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and R ^Three Is a linear or branched alkylene group having 1 to 12 carbon atoms or —O—R ′ — (R ′ is a linear or branched alkylene group having 2 or 3 carbon atoms. ) And R ^Four Represents a hydrogen atom or a methyl group. )

(Wherein R ¹ , R ^Four Represents the same meaning as above, R ^Five Represents a hydrogen atom or a hydroxyl group, R ⁶ Represents a hydrogen atom or a C1-C6 alkoxy group, R ⁷ Represents a linear or branched alkylene group having 1 to 12 carbon atoms. )

(Where R ^Four Represents the same meaning as above, R ⁸ Is a direct bond,-(CH ₂ CH ₂ O) p- or -CH ₂ CH (OH) -CH ₂ O- represents, and p represents an integer of 1 to 5. R ⁹ , R ^Ten , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ Each independently represents a hydrogen atom, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group or an alkyl group. )
Is at least one selected from monomers represented by:
The monomer having an alkyl group having 4 or more carbon atoms is represented by the following general formula (B)

(Wherein R ¹⁷ Represents a hydrogen atom or a methyl group, and X represents a hydrocarbon group having 4 or more carbon atoms. )
A (meth) acrylate monomer represented by
The monomer having the UV-stable group is represented by the following general formula (C-1)

(Wherein R ¹⁸ Represents a hydrogen atom or a cyano group, R ¹⁹ , R ²⁰ Each independently represents a hydrogen atom or a methyl group; ^{twenty one} Represents a hydrogen atom or a hydrocarbon group, and Y represents an oxygen atom or an imino group. ),
And / or the following general formula (C-2)

(Wherein R ^{twenty two} Represents a hydrogen atom or a cyano group, R ^{twenty three} , R ^{twenty four} , R ^{twenty five} , R ²⁶ Each independently represents a hydrogen atom or a methyl group, and Z represents an oxygen atom or an imino group. ), A monomer represented by
A resin composition used for forming an ultraviolet shielding layer for a dye-sensitized solar cell. A polymer synthesized from a monomer mixture (II) containing a monomer having an alkyl group having 4 or more carbon atoms and / or a monomer having an ultraviolet light-stable group, and an additive ultraviolet absorber;
The monomer having an alkyl group having 4 or more carbon atoms is represented by the following general formula (B)

(Wherein R ¹⁷ Represents a hydrogen atom or a methyl group, and X represents a hydrocarbon group having 4 or more carbon atoms. )
A (meth) acrylate monomer represented by
The monomer having the UV-stable group is represented by the following general formula (C-1)

(Wherein R ¹⁸ Represents a hydrogen atom or a cyano group, R ¹⁹ , R ²⁰ Each independently represents a hydrogen atom or a methyl group; ^{twenty one} Represents a hydrogen atom or a hydrocarbon group, and Y represents an oxygen atom or an imino group. ),
And / or the following general formula (C-2)

(Wherein R ^{twenty two} Represents a hydrogen atom or a cyano group, R ^{twenty three} , R ^{twenty four} , R ^{twenty five} , R ²⁶ Each independently represents a hydrogen atom or a methyl group, and Z represents an oxygen atom or an imino group. ), A monomer represented by
A resin composition used for forming an ultraviolet shielding layer for a dye-sensitized solar cell. The resin composition according to claim 7 or 8, wherein the monomer mixture (I) or (II) further contains a monomer having a crosslinkable functional group. Furthermore, the resin composition in any one of Claims 7-9 which contains a silane coupling agent. A polymer synthesized from a monomer mixture (I) comprising a monomer having an ultraviolet absorbing group, a monomer having an alkyl group having 4 or more carbon atoms, and / or a monomer having an ultraviolet stable group,
The monomer having the ultraviolet absorbing group is represented by the following general formulas (A-1) to (A-3).

(Wherein R ¹ Represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R ² Represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and R ^Three Is a linear or branched alkylene group having 1 to 12 carbon atoms or —O—R ′ — (R ′ is a linear or branched alkylene group having 2 or 3 carbon atoms. ) And R ^Four Represents a hydrogen atom or a methyl group. )

(Wherein R ¹ , R ^Four Represents the same meaning as above, R ^Five Represents a hydrogen atom or a hydroxyl group, R ⁶ Represents a hydrogen atom or a C1-C6 alkoxy group, R ⁷ Represents a linear or branched alkylene group having 1 to 12 carbon atoms. )

(Where R ^Four Represents the same meaning as above, R ⁸ Is a direct bond,-(CH ₂ CH ₂ O) p- or -CH ₂ CH (OH) -CH ₂ O- represents, and p represents an integer of 1 to 5. R ⁹ , R ^Ten , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ Each independently represents a hydrogen atom, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group or an alkyl group. )
Is at least one selected from monomers represented by:
The monomer having an alkyl group having 4 or more carbon atoms is represented by the following general formula (B)

(Wherein R ¹⁷ Represents a hydrogen atom or a methyl group, and X represents a hydrocarbon group having 4 or more carbon atoms. )
A (meth) acrylate monomer represented by
The monomer having the UV-stable group is represented by the following general formula (C-1)

(Wherein R ¹⁸ Represents a hydrogen atom or a cyano group, R ¹⁹ , R ²⁰ Each independently represents a hydrogen atom or a methyl group; ^{twenty one} Represents a hydrogen atom or a hydrocarbon group, and Y represents an oxygen atom or an imino group. ),
And / or the following general formula (C-2)

(Wherein R ^{twenty two} Represents a hydrogen atom or a cyano group, R ^{twenty three} , R ^{twenty four} , R ^{twenty five} , R ²⁶ Each independently represents a hydrogen atom or a methyl group, and Z represents an oxygen atom or an imino group. An ultraviolet shielding layer for a dye-sensitized solar cell, which is a monomer represented by A polymer synthesized from a monomer mixture (II) containing a monomer having an alkyl group having 4 or more carbon atoms and / or a monomer having an ultraviolet light-stable group, and an additive ultraviolet absorber;
The monomer having an alkyl group having 4 or more carbon atoms is represented by the following general formula (B)

(Wherein R ¹⁷ Represents a hydrogen atom or a methyl group, and X represents a hydrocarbon group having 4 or more carbon atoms. )
A (meth) acrylate monomer represented by
The monomer having the UV-stable group is represented by the following general formula (C-1)

(Wherein R ¹⁸ Represents a hydrogen atom or a cyano group, R ¹⁹ , R ²⁰ Each independently represents a hydrogen atom or a methyl group; ^{twenty one} Represents a hydrogen atom or a hydrocarbon group, and Y represents an oxygen atom or an imino group. ),
And / or the following general formula (C-2)

(Wherein R ^{twenty two} Represents a hydrogen atom or a cyano group, R ^{twenty three} , R ^{twenty four} , R ^{twenty five} , R ²⁶ Each independently represents a hydrogen atom or a methyl group, and Z represents an oxygen atom or an imino group. An ultraviolet shielding layer for a dye-sensitized solar cell, which is a monomer represented by The ultraviolet shielding layer for a dye-sensitized solar cell according to claim 11 or 12, wherein the monomer mixture (I) or (II) further contains a monomer having a crosslinkable functional group. The ultraviolet shielding layer for a dye-sensitized solar cell according to any one of claims 11 to 13, which is directly formed on a glass substrate of the dye-sensitized solar cell. Furthermore, the ultraviolet-ray shielding layer for dye-sensitized solar cells of Claim 14 which contains a silane coupling agent. The ultraviolet shielding layer for a dye-sensitized solar cell according to any one of claims 11 to 13, which is directly or indirectly formed on a plastic substrate of the dye-sensitized solar cell.