JP2004091380A - Acrylic acid derivative compound, composition, polymer liquid crystal polymerized from the same, and use - Google Patents

Abstract

The present invention provides a photopolymerizable liquid crystal compound having a large birefringence and exhibiting a liquid crystal phase at high temperatures. A polymer liquid crystal obtained by photopolymerizing a composition containing this compound is suitable as an optical element for an optical head.
An acrylic acid derivative compound having a mesogenic skeleton having three phenylene groups and at least one linking group connecting the phenylene groups is an ethynylene group, a liquid crystal composition containing the compound, and the liquid crystal composition Polymer liquid crystal formed by polymerizing
[Selection] Figure 1

Description

【０００５】
式（２）で表される化合物（以下、化合物２ともいい、他の場合も同様である。）は、液晶の複屈折率が大きく、高温でネマチック液晶性を示す優れた化合物である。しかし、複屈折率がより大きい化合物が求められていた。
【０００６】
【発明が解決しようとする課題】
本発明の目的は、第１に複屈折率が大きく、かつ高温で液晶性を示す光重合性液晶モノマの提供であり、第２に該モノマを含む液晶組成物さらにこれを重合して得られる高分子液晶およびその用途の提供にある。
【０００７】
【課題を解決するための手段】
本発明は、下記式（１）で表されるアクリル酸誘導体化合物（以下、化合物１ともいう。）を提供する。
【０００８】
【化４】

【０００９】
Ｒ：水素原子またはメチル基。
Ｓ^１：それぞれ独立して、単結合、−Ｏ−、−ＣＯＯ−または−ＯＣＯ−を表す。
Ｓ^２、Ｓ^３：それぞれ独立して、単結合、−ＣＯＯ−または−ＯＣＯ−を表す。
Ｔ^１、Ｔ^２、Ｔ^３：それぞれ独立して、１個以上の水素原子がメチル基、フッ素原子、塩素原子に置換されていてもよい、および／または１個以上の＝ＣＨ−が−Ｎ＝に置換されていてもよい１，４−フェニレン基。
Ｕ：トリフロロメチル基、トリフロロメトキシ基、シアノ基、イソチオシアネート基、フッ素原子または塩素原子。
ｍ：０〜８の整数。
ｎ：ｍが０の場合は０、ｍが１〜８の場合は１。
ｘ、ｙ：それぞれ独立して、０または１であり、かつｘ＋ｙ≠０。
【００１０】
また、本発明は、化合物１から選ばれる１種以上を組成物中に５％（モル基準である。以下、特に記載のない限り同様である。）以上含む液晶組成物を提供する。
【００１１】
本発明は、該組成物を重合させてなる高分子液晶、該高分子液晶を用いてなる光学素子、および該光学素子を用いてなる光ヘッドを提供する。
【００１２】
【発明の実施の形態】
本発明におけるアクリル酸誘導体化合物とは、ＣＨ_２＝ＣＨＣＯＯ−またはＣＨ_２＝Ｃ（ＣＨ_３）ＣＯＯ−を有する化合物の総称である。
【００１３】
本発明の化合物１は、光重合性の官能基であるアクリロイルオキシ基と液晶骨格とを有し、該アクリロイルオキシ基と液晶骨格との間に、必要に応じてアルキレン基、アルキレンオキシ基、アルキレンオキシカルボニル基またはアルキレンカルボニルオキシ基を挿入した分子構造を有する。液晶骨格とは、２以上の２価の環基が単結合、−ＣＯＯ−、−ＯＣＯ−、−Ｃ≡Ｃ−などを介して結合した基のことである。
【００１４】
化合物１の液晶骨格は、３つの１，４−フェニレン基すなわちＴ^１、Ｔ^２、Ｔ^３を有し、かつＴ^１とＴ^２との間および／またはＴ^２とＴ^３との間にエチニレン基を有するメソゲン骨格である。化合物１は、エチニレン基を結合基として有するため、化合物２（液晶骨格が、−Ｐｈ−ＣＯＯ−Ｐｈ−Ｐｈ−である化合物。）よりも大きな複屈折率を示す。また、化合物１は、３つの１，４−フェニレン基を有するため、高温で液晶性を示す。
【００１５】
本発明におけるＲは、水素原子またはメチル基である。Ｒは、水素原子であることが好ましい。
【００１６】
本発明におけるＳ^１は、それぞれ独立して、単結合、−Ｏ−、−ＣＯＯ−または−ＯＣＯ−である。
【００１７】
本発明におけるＳ^２、Ｓ^３は、それぞれ独立して、単結合、−ＣＯＯ−または−ＯＣＯ−である。
【００１８】
本発明におけるＴ^１、Ｔ^２、Ｔ^３は、それぞれ独立して、１個以上の水素原子がメチル基、フッ素原子、塩素原子に置換されていてもよい、および／または１個以上の＝ＣＨ−が＝Ｎ−に置換されていてもよい１，４−フェニレン基である。＝ＣＨ−が＝Ｎ−に置換された場合、化合物１の複屈折率が大きくなるため好ましい。水素原子がメチル基、フッ素原子または塩素原子に置換された場合、化合物１の融点が低くなるため好ましい。特に、水素原子がフッ素原子に置換された場合、化合物１の粘度も低くなるため好ましい。
【００１９】
本発明におけるＵは、シアノ基、イソチオシアネート基、フッ素原子または塩素原子である。Ｕは、シアノ基であると、化合物１の複屈折率が大きくなりかつ化学的に安定であるため好ましい。
【００２０】
本発明におけるｍは、０〜８の整数である。本発明の化合物は、ｍが０〜８の範囲内であるので、重合後の高分子液晶の複屈折率の温度依存性の制御が容易である。
【００２１】
本発明におけるｎは、ｍが０の場合は０、ｍが１〜８の場合は１である。したがって、化合物１において、ｍ＝ｎ＝０のとき、ＣＨ_２＝ＣＲＣＯＯ−とＴ^１とは、直接結合する。直接結合している場合、化合物１の複屈折率の温度依存性が小さくなること、液晶骨格の配列の保持性、耐熱性に優れること等の利点を有する。また、化合物１において、１≦ｍ≦８かつｎ＝１のとき、ＣＨ_２＝ＣＲＣＯＯ−とＴ^１とは、−（ＣＨ_２）_ｍ−（Ｓ^１）−を介して結合する。該基を介して結合している場合、化合物１は、重合後の複屈折率の低下が小さくなる。
【００２２】
本発明におけるｘ、ｙは、それぞれ独立して、０または１であり、かつｘ＋ｙ≠０である。すなわち、化合物１は、Ｔ^１とＴ^２との間および／またはＴ^２とＴ^３との間に、エチニレン基を有する。化合物１はエチニレン基を有するため、複屈折率が大きい化合物である。
【００２３】
化合物１として、具体的には次の化合物が挙げられる。
ＣＨ_２＝ＣＨＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−ＣＨ_２−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_２−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_３−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_４−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_５−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_６−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_７−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_８−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＯＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−ＣＨ_２−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＯＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_２−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＯＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_３−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＯＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_４−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＯＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_５−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＯＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_６−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＯＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_７−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＯＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_８−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＯＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＯＣＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−ＣＨ_２−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＯＣＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_２−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＯＣＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_３−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＯＣＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_４−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＯＣＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_５−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＯＣＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_６−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＯＣＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_７−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＯＣＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_８−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＯＣＯ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−Ｐｈ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−ＣＨ_２−Ｏ−Ｐｈ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_２−Ｏ−Ｐｈ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_３−Ｏ−Ｐｈ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_４−Ｏ−Ｐｈ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_５−Ｏ−Ｐｈ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_６−Ｏ−Ｐｈ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_７−Ｏ−Ｐｈ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_８−Ｏ−Ｐｈ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−Ｐｈ−ＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−ＣＨ_２−Ｏ−Ｐｈ−ＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_２−Ｏ−Ｐｈ−ＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_３−Ｏ−Ｐｈ−ＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_４−Ｏ−Ｐｈ−ＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_５−Ｏ−Ｐｈ−ＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_６−Ｏ−Ｐｈ−ＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_７−Ｏ−Ｐｈ−ＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_８−Ｏ−Ｐｈ−ＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−Ｐｈ−ＯＣＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−ＣＨ_２−Ｏ−Ｐｈ−ＯＣＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_２−Ｏ−Ｐｈ−ＯＣＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_３−Ｏ−Ｐｈ−ＯＣＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_４−Ｏ−Ｐｈ−ＯＣＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_５−Ｏ−Ｐｈ−ＯＣＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_６−Ｏ−Ｐｈ−ＯＣＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_７−Ｏ−Ｐｈ−ＯＣＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_８−Ｏ−Ｐｈ−ＯＣＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−ＣＨ_２−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_２−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_３−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_４−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_５−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_６−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_７−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ
ＣＨ_２＝ＣＨＣＯＯ−（ＣＨ_２）_８−Ｏ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−Ｃ≡Ｃ−Ｐｈ−ＣＮ。
【００２４】
化合物１は例えば次に示す方法によって合成できる。
ヒドロキシアルキルブロマイド（化合物４）と４−ヒドロキシ安息香酸（化合物３）とをアルカリ下で反応させて、４−（ヒドロキシアルキルオキシ）安息香酸（化合物５）を得る。これをトリエチルアミンなどの塩基の存在下、アクリル酸クロライド（化合物６）を反応させて、４−（アクリロイルオキシアルキルオキシ）安息香酸（化合物７）を得る。さらに、塩化チオニル（化合物８）と反応させて、４−（アクリロイルオキシアルキルオキシ）安息香酸クロライド（化合物９）とした後、続いてトリエチルアミンなどの塩基の存在下、４−ヒドロキシ（（４’−シアノ）フェニルエチニル）ベンゼン（化合物１０）と反応させて、４−（アクリロイルオキシアルキルオキシ）安息香酸（（４’−シアノ）フェニルエチニル）フェニル（化合物１１）を得る。
【００２５】
【化５】

【００２６】
化合物１の合成方法は上記方法に限定されず、他の合成方法で得ることもできる。この化合物１を含む液晶組成物は高温まで広い範囲で液晶性を示し、大きな複屈折率を発現することができる。
【００２７】
本発明の組成物は、組成物中に化合物１を５％以上含むのが好ましく、１０〜９０％がより好ましく、２０〜８０％がさらに好ましい。化合物１が５％以上であると、本発明の組成物の複屈折率が大きくなるため好ましい。化合物１は、１種を単独で用いてもよいし、２種以上を組み合わせて用いてもよい。
【００２８】
本発明の組成物には、化合物１以外のその他の化合物を含むことができる。その他の化合物としては、重合性二重結合を有する重合性化合物が好ましく、重合性二重結合と液晶骨格とを有する重合性液晶化合物がより好ましい。特に化合物１以外の液晶骨格を有するアクリル酸誘導体化合物が、良好な光重合性を有するため好ましい。
【００２９】
他の重合性液晶化合物は、液晶骨格と重合性官能基を有する公知の化合物であれば特に限定されない。液晶骨格としては少なくとも２つまたは３つの六員環を有するものが好ましい。
【００３０】
本発明の化合物１またはそれ含んでなる組成物は、重合し高分子液晶を形成することができる。
【００３１】
該重合としては、光重合が好ましい。光重合に用いる光としては、紫外線、可視光線等が挙げられる。
【００３２】
光重合を行う場合には、光重合開始剤を用いると効率よく重合できる。光重合開始剤としては特に限定されず、アセトフェノン類、ベンゾフェノン類、ベンゾイン類、ベンジル類、ミヒラーケトン類、ベンゾインアルキルエーテル類、ベンジルジメチルケタール類、チオキサントン類などが好ましく使用できる。また必要に応じ、２種以上の光重合開始剤を混合使用してもよい。光重合開始剤の使用量は、組成物に対して０．１〜１０％（質量基準である。）が好ましく、特に０．３〜２％（質量基準である。）が好ましい。
【００３３】
本発明の組成物を重合させる際には、複数枚の支持体の間にガラスビーズ等のスペーサを配置し、該支持体を所望の間隔に制御して対向させ、支持体間に本発明の組成物を注入し、充填させて重合させるのが好ましい。該支持体としては、ガラス板、プラスチック板等を使用できる。
【００３４】
また、支持体表面には配向処理が施されているのが好ましい。配向処理は、支持体面を斜方蒸着するか、綿、羊毛等の天然繊維、ナイロン、ポリエステル等の合成繊維等で直接ラビングするか、またはポリイミド、ポリアミド等を塗布しその面を上記繊維等でラビングするのがよい。
【００３５】
重合性液晶組成物を液晶状態に保つためには、雰囲気温度を融点Ｔ_ｍ［℃］以上、等方相相転移温度Ｔ_ｃ［℃］以下の範囲にするのが好ましいが、Ｔ_ｃに近い温度では複屈折率がきわめて小さいので、雰囲気温度の上限は（Ｔ_ｃ−１０）℃以下とするのがより好ましい。本発明の重合性液晶組成物は、重合時に比較的安定に液晶状態を保持していれば、過冷却状態のような短期的に安定な液晶状態で重合してもよい。
【００３６】
本発明の高分子液晶は支持体に挟んだまま用いてもよく、支持体から剥離して用いてもよい。
【００３７】
本発明の高分子液晶は光学素子に好適である。光学素子としては、位相差フィルムや偏光ホログラム素子等が挙げられる。本発明の高分子液晶を用いた偏光ホログラム素子は、偏光依存性を利用して高い往復効率を発現することができる。したがって、該偏光ホログラム素子を光ヘッドとして用いれば、光利用効率の高い光ヘッドを作製できる。
【００３８】
【実施例】
例１〜３および５〜８が実施例、例４が比較例である。
［例１：化合物の合成］
３００ｍＬフラスコに４−ヒドロキシ安息香酸１８．８ｇ（０．１４ｍｏｌ）を入れ、エタノールを９５ｍＬ、水酸化カリウムを１７．５ｇ（０．３１ｍｏｌ）、水を１８ｍＬ、ヨウ化カリウムを０．３８ｇ（０．１６ｍｏｌ）を室温で加え撹拌し、６０℃まで加熱した後、６−ブロモ−１−ヘキサノール２９．０ｇ（０．１７ｍｏｌ）を徐々に滴下した。更に昇温し、還流状態に保ったまま２４時間反応させた。室温まで冷却し、エタノールを減圧留去した後、水を３０ｍＬ加え、エーテル１０ｍＬで洗浄した。エーテル層を分離除去し、水層に２規定塩酸を１５ｍＬ加え、結晶を析出させた。減圧濾過し、結晶を濾取した。得られた結晶を１０００ｍＬフラスコ中でテトラヒドロフラン１０００ｍＬに溶解し、無水硫酸マグネシウム５ｇを加え乾燥させた。テトラヒドロフランを減圧留去して得られた粉末結晶を、酢酸エチルを展開液とし、シリカゲルを充填したカラムを用いて、カラムクロマトを行った。分取液中の酢酸エチルを減圧留去し、さらにエタノールで再結晶を行い、化合物１２、すなわち４−（６−ヒドロキシヘキシルオキシ）安息香酸２３．３ｇ（０．１０ｍｏｌ）を得た（収率７０％）。
【００３９】
続いて、得られた化合物２．８ｇ（１２．０ｍｍｏｌ）と、乾燥テトラヒドロフランを１２５ｍＬと、トリエチルアミンを３．０ｇ（３０ｍｍｏｌ）とを混合したものを３００ｍＬフラスコに入れ、氷水で冷却しながら、該フラスコ内の反応液の温度が５℃を超えないように、乾燥テトラヒドロフランを２．７ｇと、アクリル酸クロライド２．７ｇ（３０ｍｍｏｌ）とを混合したものを添加した。十分に反応させた後、減圧濾過し、濾液中のテトラヒドロフランを減圧留去した。残留物にジクロロメタン３０ｍＬを加え、これを５質量％炭酸水素ナトリウム水溶液３０ｍＬで洗浄し、更に水２５ｍＬで有機層を洗浄した後、有機層を無水硫酸マグネシウム１ｇにて乾燥した。ジクロロメタンを減圧留去した後、得られた黄色粘性液体を、酢酸エチルとｎ−ヘキサン（酢酸エチル：ｎ−ヘキサン＝６：４）の混合溶媒を展開液とし、シリカゲルを充填したカラムを用いて、カラムクロマトを行った。分取液中の酢酸エチルとｎ−ヘキサンの混合溶媒を減圧留去し、さらにエタノール５ｍＬで再結晶を行い、白色結晶の化合物１３、すなわち４−（（６−アクリロイルオキシ）ヘキシルオキシ）安息香酸１．５ｇ（５．４ｍｍｏｌ）を得た（収率４５％）。
【００４０】
５０ｍＬフラスコに十分に乾燥させた１．５ｇ（５．４ｍｍｏｌ）の化合物１３と、ジクロロメタン１０ｍＬと、塩化チオニルを１．３ｇ（１０．７ｍｍｏｌ）とＮ、Ｎ−ジメチルホルムアミドを数滴とを加え、室温で１ｈｒ撹拌した。過剰の塩化チオニルを減圧留去し、液体の化合物１４、すなわち４−（（６−アクリロイルオキシ）ヘキシルオキシ）安息香酸クロライド１．６ｇ（５．１ｍｍｏｌ）を得た（収率９４％）。
【００４１】
５０ｍＬフラスコに化合物１０すなわち４−ヒドロキシ（（４’−シアノ）フェニルエチニル）ベンゼン１．１ｇ（５．０ｍｍｏｌ）と、乾燥テトラヒドロフランを１２ｍＬと、トリエチルアミンを０．６１ｇ（５．９ｍｍｏｌ）とを加え混合したものを氷水で冷却しながら、該フラスコ内の反応液の温度が５℃を超えないように、１．６ｇ（５．１ｍｏｌ）の化合物１４と乾燥テトラヒドロフラン２ｍＬの混合物を添加した。反応後、析出塩を減圧濾過し取り除き、濾液中のテトラヒドロフランを減圧留去した。残留物にジクロロメタン２０ｍＬを加えた。５質量％炭酸水素ナトリウム水溶液２０ｍＬで洗浄し、更に水２５ｍＬで有機層を洗浄し、有機層を無水硫酸マグネシウムにて乾燥した。ジクロロメタンを減圧留去し、黄色固体を得た。ジクロロメタンを展開液とし、シリカゲルを充填したカラムを用いて、カラムクロマトを行った。分取液中のジクロロメタンを減圧留去し、さらにエタノール５ｍＬで再結晶を行い、白色結晶として化合物１５、すなわち４−（（６−アクリロイルオキシ）ヘキシルオキシ）安息香酸（４−（（４’−シアノ）フェニルエチニル）フェニル）１．７ｇ（３．５ｍｍｏｌ）を得た（収率７０％）。
【００４２】
【化６】

【００４３】
化合物１５の赤外吸収スペクトル（ＫＢｒ錠剤）を図１に示す。
また、^１Ｈ−ＮＭＲスペクトル（ＣＤＣｌ_３溶媒、ＴＭＳ内部標準）は、δ（ｐｐｍ）：１．４３（４Ｈ，ｍ）、１．６８（４Ｈ，ｍ）、４．０９（４Ｈ，ｍ）、５．９２（１Ｈ，ｄ）、６．１５（１Ｈ，ｄｄ）、６．３１（１Ｈ，ｄ）、７．１０（２Ｈ，ｄ）、７．３６（２Ｈ，ｄ）、７．７２（４Ｈ，ｍ）、７．８９（２Ｈ，ｄ）、８．０６（２Ｈ，ｄ）であった。
【００４４】
化合物１５を偏光顕微鏡で観察しながら室温から昇温させた結果、１０４℃で結晶からネマチック液晶に変化し、１６０℃まではネマチック液晶であることを確認した。それ以上の温度では、重合したためネマチック液晶から等方性液体への相転移温度は確認できなかった。また、前記と同様に１５０℃まで昇温した後、降温した時、１０４℃でネマチック液晶から結晶への相転移が観察され、本化合物がエナンショトロピック液晶であることを確認した。
【００４５】
［例３：化合物の複屈折率］
Ｔ_ｃが８５℃、式１６で求められる温度Ｔｓ（℃）における複屈折率Δｎ（Ｘ_０）_Ｔｓが０．１１９である液晶モノマＸ_０を用い、さらに次のように計算される複屈折率Δｎ_Ｔｓを化合物の複屈折率と定義する。複屈折率は５８９ｎｍで求めたものである。液晶モノマＸ_０に化合物１５を１０ｍｏｌ％溶解した液晶組成物Ｘ_１を作製した。この組成物Ｘ_１のＴ_ｃは１０５℃であり、式１６で求められる温度Ｔｓにて測定した液晶組成物Ｘ_１の複屈折率Δｎ（Ｘ_１）_Ｔｓは０．１４２であった。Δｎ（Ｘ_０）_ＴｓおよびΔｎ（Ｘ_１）_Ｔｓを式１７に代入し、計算した化合物１５の複屈折率Δｎ_Ｔｓは０．３６１であった。
【００４６】
【化７】

【００４７】
［例４：化合物の複屈折率（比較例）］
例３と同様にして、化合物２の複屈折率Δｎ_Ｔｓをもとめたところ、０．２４４であった。
【００４８】
化合物２を偏光顕微鏡で観察しながら室温から昇温させた結果、１０６℃で結晶からネマチック液晶に変化し、１６０℃まではネマチック液晶であることを確認した。それ以上の温度では、重合したためネマチック液晶から等方性液体への相転移温度は確認できなかった。また前記と同様に１５０℃まで昇温した後、降温した時、１０６℃でネマチック液晶から結晶へ相転移し、エナンショトロピック液晶であった。
【００４９】
［例５：高分子液晶の作製］
組成物全量に対して、化合物１５すなわち４−（（６−アクリロイルオキシ）ヘキシルオキシ）安息香酸（４−（（４’−シアノ）フェニルエチニル）フェニル）が２０％、化合物１８すなわち、４−（（４−アクリロイルオキシブチル）オキシ）−４’−シアノトランが５０％、化合物１９すなわち、４，４’−ジ−（（４−アクリロイルオキシブチル）オキシ）トランが３０％からなる組成物Ａを調製した。組成物Ａは融点４６℃、それ以上でネマチック液晶であった。Ｔ_ｃは、８６℃であった。
【００５０】
【化８】

【００５１】
配向剤であるポリイミドをスピンコータで塗布し、熱処理した後、ナイロンクロスで一定方向にラビング処理したガラス板を支持体とし、配向処理した面が向かいあうように２枚の支持体を接着剤を用いて貼り合わせてセルＭを作製した。その際、１辺にガラスブロックを挿入し、くさび形状となるセルを作製した。セルＭにおける、くさび頂角は１．６度、寸法は縦１７ｍｍ、横３０ｍｍであり、ラビング方向はくさび先端の頂辺方向に対して１８０度である。
【００５２】
組成物Ａに光重合開始剤「イルガキュアー９０７（チバ・スペシャルティー・ケミカルズ社製）」０．５質量％添加したものを、上記のように作製したセルＭに８６℃で注入した。次に５０℃で波長３６５ｎｍ、５０ｍＷ／ｃｍ^２の強度の紫外線を６０秒照射し、光重合を行った。重合後、フィルム状の高分子液晶Ａが得られた。この高分子液晶Ａは可視域で透明であり、散乱もみられなかった。波長５８９ｎｍの光を用いて、温度３０℃で測定したΔｎは０．２５１であった。
【００５３】
［例６（実施例）］
ピッチ１０μｍ、深さ１．４μｍの矩形格子が形成された直径７５ｍｍの円板状のガラス基板上に、配向剤であるポリイミドをスピンコータで塗布し、熱処理した後、ナイロンクロスで格子方向に対して平行方向にラビング処理を行ったものと、配向処理を同様に行ったガラス基板とを、配向処理面が向かいあい、基板間隔が２μｍになるように接着剤を用いて貼り合わせて、セルＮを作製した。その際、配向方向が平行になるようにした。
【００５４】
組成物Ａに光重合開始剤「イルガキュアー９０７（チバ・スペシャルティー・ケミカルズ社製）」０．５質量％添加したものを、上記のように作製したセルＮに８６℃で注入し、格子状凹部を組成物Ａにより充填した。次に、５０℃で、波長３６５ｎｍ、５０ｍＷ／ｃｍ^２の強度の紫外線を６０秒照射し、光重合を行った。このセルＮの片面に１／４波長板を積層し、偏光ホログラムビームスプリッタ（光学素子）を作製した。この偏光ホログラムビームスプリッタを光ヘッドの部品に用いたところ、該光ヘッドは波長６５０ｎｍのレーザ光源にて、±１次の回折効率の合計で５０％の光利用効率を得た。
【００５５】
［例７（実施例）］
化合物１５に光重合開始剤「イルガキュアー９０７（チバ・スペシャルティー・ケミカルズ社製）」０．５質量％添加したものを、前述のセルＭに１１０℃で注入した。次に１１０℃で波長３６５ｎｍ、５０ｍＷ／ｃｍ^２の強度の紫外線を６０秒照射し、光重合を行った。重合後、フィルム状の高分子液晶Ｂが得られた。この高分子液晶Ｂは可視域で透明であり、散乱もみられなかった。波長５８９ｎｍの光を用いて、温度３０℃で測定したΔｎは０．３１８であった。
【００５６】
【発明の効果】
本発明の化合物は、高温で液晶性を発現できる光重合性液晶モノマである。すなわち、液晶組成物の成分として本発明の化合物を用いた場合、等方相相転移温度の高い液晶組成物を得ることができる。
【００５７】
本発明の化合物を用いて高分子液晶を作成した場合、複屈折率が大きい高分子液晶を得ることができる。
【００５８】
また、本発明の化合物およびこれを用いた組成物は、光重合により高分子液晶を作製できる。この高分子液晶は、散乱がないため、光学素子として好適である。該高分子液晶は、光学素子として、位相差フィルムや偏光ホログラム素子などに使用でき、特に偏光ホログラム素子は、光ヘッドとして好適である。本発明は、本発明の効果を損しない範囲内で、種々応用できる。
【図面の簡単な説明】
【図１】化合物１５の赤外吸収スペクトル図。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an acrylic acid derivative compound, a liquid crystal composition containing the compound, a polymer liquid crystal obtained by polymerizing the composition, and a use.
[0002]
[Prior art]
A polymerizable liquid crystal monomer in which a polymerizable functional group is added to the liquid crystal monomer has both a property as a monomer and a property as a liquid crystal. Accordingly, when the polymerizable liquid crystal monomer is polymerized in an aligned state, a polymer liquid crystal in which the alignment is maintained and the alignment is fixed can be obtained. The polymer liquid crystal thus obtained has optical anisotropy based on the birefringence of the liquid crystalline skeleton, and can also be given special properties by controlling the liquid crystal alignment state, so that it is applied to retardation films and polarization hologram elements. .
[0003]
Among such polymerizable liquid crystal monomers, in particular, a photopolymerizable liquid crystal monomer having a photopolymerizable functional group is an excellent material whose alignment can be easily fixed by light irradiation. As a photopolymerizable liquid crystal monomer, for example, an acrylic acid derivative compound represented by the following formula (2) is known (in the present specification, Ph represents a 1,4-phenylene group) (special feature). No. 2001-220583).
[0004]
[Chemical Formula 3]

[0005]
The compound represented by formula (2) (hereinafter also referred to as compound 2 and the same applies in other cases) is an excellent compound having a large birefringence of liquid crystal and exhibiting nematic liquid crystal properties at high temperatures. However, a compound having a higher birefringence has been demanded.
[0006]
[Problems to be solved by the invention]
An object of the present invention is first to provide a photopolymerizable liquid crystal monomer having a large birefringence and exhibiting liquid crystallinity at a high temperature, and secondly, a liquid crystal composition containing the monomer and obtained by polymerizing this. It is in providing a polymer liquid crystal and its use.
[0007]
[Means for Solving the Problems]
The present invention provides an acrylic acid derivative compound (hereinafter also referred to as Compound 1) represented by the following formula (1).
[0008]
[Formula 4]

[0009]
R: a hydrogen atom or a methyl group.
S ¹ : Each independently represents a single bond, —O—, —COO— or —OCO—.
S ² , S ³ : Each independently represents a single bond, —COO— or —OCO—.
T ¹ , T ² , T ³ : Independently, one or more hydrogen atoms may be substituted with a methyl group, a fluorine atom or a chlorine atom, and / or one or more ═CH— may be substituted with —N═. 1,4-phenylene group.
U: trifluoromethyl group, trifluoromethoxy group, cyano group, isothiocyanate group, fluorine atom or chlorine atom.
m: An integer from 0 to 8.
n: 0 when m is 0, 1 when m is 1-8.
x, y: each independently 0 or 1, and x + y ≠ 0.
[0010]
In addition, the present invention provides a liquid crystal composition containing at least 5% (on a molar basis, hereinafter the same unless otherwise specified) in the composition of at least one selected from Compound 1.
[0011]
The present invention provides a polymer liquid crystal obtained by polymerizing the composition, an optical element using the polymer liquid crystal, and an optical head using the optical element.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The acrylic acid derivative compound in the present invention is CH. ₂ = CHCOO- or CH ₂ = C (CH ₃ ) A generic term for compounds having COO-.
[0013]
The compound 1 of the present invention has an acryloyloxy group that is a photopolymerizable functional group and a liquid crystal skeleton, and an alkylene group, an alkyleneoxy group, an alkylene group is optionally provided between the acryloyloxy group and the liquid crystal skeleton. It has a molecular structure in which an oxycarbonyl group or an alkylenecarbonyloxy group is inserted. The liquid crystal skeleton is a group in which two or more divalent ring groups are bonded through a single bond, —COO—, —OCO—, —C≡C— or the like.
[0014]
The liquid crystal skeleton of Compound 1 has three 1,4-phenylene groups, ie, T ¹ , T ² , T ³ And T ¹ And T ² And / or T ² And T ³ And a mesogenic skeleton having an ethynylene group between them. Since Compound 1 has an ethynylene group as a linking group, it exhibits a higher birefringence than Compound 2 (a compound in which the liquid crystal skeleton is —Ph—COO—Ph—Ph—). In addition, since Compound 1 has three 1,4-phenylene groups, it exhibits liquid crystallinity at high temperatures.
[0015]
R in the present invention is a hydrogen atom or a methyl group. R is preferably a hydrogen atom.
[0016]
S in the present invention ¹ Each independently represents a single bond, —O—, —COO— or —OCO—.
[0017]
S in the present invention ² , S ³ Are each independently a single bond, —COO— or —OCO—.
[0018]
T in the present invention ¹ , T ² , T ³ Each independently, one or more hydrogen atoms may be substituted with a methyl group, a fluorine atom or a chlorine atom, and / or one or more ═CH— may be substituted with ═N—. A good 1,4-phenylene group. When ═CH— is replaced by ═N—, the birefringence of Compound 1 is increased, which is preferable. When a hydrogen atom is substituted with a methyl group, a fluorine atom or a chlorine atom, the melting point of Compound 1 is lowered, which is preferable. In particular, when a hydrogen atom is substituted with a fluorine atom, the viscosity of the compound 1 is decreased, which is preferable.
[0019]
U in the present invention is a cyano group, an isothiocyanate group, a fluorine atom or a chlorine atom. U is preferably a cyano group because the birefringence of compound 1 is increased and it is chemically stable.
[0020]
M in the present invention is an integer of 0 to 8. In the compound of the present invention, since m is in the range of 0 to 8, the temperature dependence of the birefringence of the polymer liquid crystal after polymerization can be easily controlled.
[0021]
In the present invention, n is 0 when m is 0, and 1 when m is 1 to 8. Therefore, in compound 1, when m = n = 0, CH ₂ = CRCOO- and T ¹ And directly bind. In the case of direct bonding, there are advantages such that the temperature dependence of the birefringence of compound 1 is reduced, the retention of the alignment of the liquid crystal skeleton, and the heat resistance are excellent. In Compound 1, when 1 ≦ m ≦ 8 and n = 1, CH ₂ = CRCOO- and T ¹ Is-(CH ₂ ) _m -(S ¹ )-. In the case of bonding through the group, Compound 1 has a small decrease in birefringence after polymerization.
[0022]
In the present invention, x and y are each independently 0 or 1, and x + y ≠ 0. That is, Compound 1 is T ¹ And T ² And / or T ² And T ³ And an ethynylene group. Since compound 1 has an ethynylene group, it is a compound having a large birefringence.
[0023]
Specific examples of the compound 1 include the following compounds.
CH ₂ = CHCOO-Ph-C≡C-Ph-Ph-CN
CH ₂ = CHCOO-CH ₂ -O-Ph-C≡C-Ph-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₂ -O-Ph-C≡C-Ph-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₃ -O-Ph-C≡C-Ph-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₄ -O-Ph-C≡C-Ph-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₅ -O-Ph-C≡C-Ph-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₆ -O-Ph-C≡C-Ph-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₇ -O-Ph-C≡C-Ph-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₈ -O-Ph-C≡C-Ph-Ph-CN
CH ₂ = CHCOO-Ph-C≡C-Ph-COO-Ph-CN
CH ₂ = CHCOO-CH ₂ -O-Ph-C≡C-Ph-COO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₂ -O-Ph-C≡C-Ph-COO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₃ -O-Ph-C≡C-Ph-COO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₄ -O-Ph-C≡C-Ph-COO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₅ -O-Ph-C≡C-Ph-COO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₆ -O-Ph-C≡C-Ph-COO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₇ -O-Ph-C≡C-Ph-COO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₈ -O-Ph-C≡C-Ph-COO-Ph-CN
CH ₂ = CHCOO-Ph-C≡C-Ph-OCO-Ph-CN
CH ₂ = CHCOO-CH ₂ -O-Ph-C≡C-Ph-OCO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₂ -O-Ph-C≡C-Ph-OCO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₃ -O-Ph-C≡C-Ph-OCO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₄ -O-Ph-C≡C-Ph-OCO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₅ -O-Ph-C≡C-Ph-OCO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₆ -O-Ph-C≡C-Ph-OCO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₇ -O-Ph-C≡C-Ph-OCO-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₈ -O-Ph-C≡C-Ph-OCO-Ph-CN
CH ₂ = CHCOO-Ph-Ph-C≡C-Ph-CN
CH ₂ = CHCOO-CH ₂ -O-Ph-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₂ -O-Ph-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₃ -O-Ph-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₄ -O-Ph-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₅ -O-Ph-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₆ -O-Ph-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₇ -O-Ph-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₈ -O-Ph-Ph-C≡C-Ph-CN
CH ₂ = CHCOO-Ph-COO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO-CH ₂ -O-Ph-COO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₂ -O-Ph-COO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₃ -O-Ph-COO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₄ -O-Ph-COO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₅ -O-Ph-COO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₆ -O-Ph-COO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₇ -O-Ph-COO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₈ -O-Ph-COO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO-Ph-OCO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO-CH ₂ -O-Ph-OCO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₂ -O-Ph-OCO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₃ -O-Ph-OCO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₄ -O-Ph-OCO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₅ -O-Ph-OCO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₆ -O-Ph-OCO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₇ -O-Ph-OCO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₈ -O-Ph-OCO-Ph-C≡C-Ph-CN
CH ₂ = CHCOO-Ph-C≡C-Ph-C≡C-Ph-CN
CH ₂ = CHCOO-CH ₂ -O-Ph-C≡C-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₂ -O-Ph-C≡C-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₃ -O-Ph-C≡C-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₄ -O-Ph-C≡C-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₅ -O-Ph-C≡C-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₆ -O-Ph-C≡C-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₇ -O-Ph-C≡C-Ph-C≡C-Ph-CN
CH ₂ = CHCOO- (CH ₂ ) ₈ -O-Ph-C≡C-Ph-C≡C-Ph-CN.
[0024]
Compound 1 can be synthesized, for example, by the following method.
Hydroxyalkyl bromide (Compound 4) and 4-hydroxybenzoic acid (Compound 3) are reacted in the presence of alkali to give 4- (hydroxyalkyloxy) benzoic acid (Compound 5). This is reacted with acrylic acid chloride (compound 6) in the presence of a base such as triethylamine to obtain 4- (acryloyloxyalkyloxy) benzoic acid (compound 7). Furthermore, after reacting with thionyl chloride (compound 8) to give 4- (acryloyloxyalkyloxy) benzoic acid chloride (compound 9), 4-hydroxy ((4′- Reaction with cyano) phenylethynyl) benzene (compound 10) yields 4- (acryloyloxyalkyloxy) benzoic acid ((4′-cyano) phenylethynyl) phenyl (compound 11).
[0025]
[Chemical formula 5]

[0026]
The method for synthesizing Compound 1 is not limited to the above method, and can be obtained by other synthesis methods. The liquid crystal composition containing the compound 1 exhibits liquid crystallinity in a wide range up to a high temperature and can exhibit a large birefringence.
[0027]
The composition of the present invention preferably contains 5% or more of Compound 1 in the composition, more preferably 10 to 90%, and still more preferably 20 to 80%. It is preferable that the compound 1 is 5% or more because the birefringence of the composition of the present invention is increased. The compound 1 may be used individually by 1 type, and may be used in combination of 2 or more type.
[0028]
The composition of the present invention can contain other compounds other than Compound 1. As the other compound, a polymerizable compound having a polymerizable double bond is preferable, and a polymerizable liquid crystal compound having a polymerizable double bond and a liquid crystal skeleton is more preferable. In particular, an acrylic acid derivative compound having a liquid crystal skeleton other than Compound 1 is preferable because it has good photopolymerizability.
[0029]
The other polymerizable liquid crystal compound is not particularly limited as long as it is a known compound having a liquid crystal skeleton and a polymerizable functional group. The liquid crystal skeleton preferably has at least two or three six-membered rings.
[0030]
The compound 1 of the present invention or a composition comprising the same can be polymerized to form a polymer liquid crystal.
[0031]
As the polymerization, photopolymerization is preferable. Examples of light used for photopolymerization include ultraviolet light and visible light.
[0032]
When photopolymerization is performed, the polymerization can be efficiently performed by using a photopolymerization initiator. The photopolymerization initiator is not particularly limited, and acetophenones, benzophenones, benzoins, benzyls, Michler ketones, benzoin alkyl ethers, benzyl dimethyl ketals, thioxanthones and the like can be preferably used. Moreover, you may mix and use 2 or more types of photoinitiators as needed. The amount of the photopolymerization initiator used is preferably 0.1 to 10% (based on mass) with respect to the composition, and particularly preferably 0.3 to 2% (based on mass).
[0033]
When polymerizing the composition of the present invention, spacers such as glass beads are arranged between a plurality of supports, the supports are controlled to face each other at a desired interval, and the present invention is supported between the supports. It is preferred to inject, fill and polymerize the composition. As the support, a glass plate, a plastic plate or the like can be used.
[0034]
The support surface is preferably subjected to an orientation treatment. Orientation treatment is performed by obliquely vapor-depositing the support surface, rubbing directly with natural fibers such as cotton and wool, synthetic fibers such as nylon and polyester, etc., or by applying polyimide, polyamide or the like and applying the surface with the above fibers or the like. It is good to rub.
[0035]
In order to keep the polymerizable liquid crystal composition in a liquid crystal state, the ambient temperature is set to the melting point T _m [℃] or more, isotropic phase transition temperature T _c [° C.] It is preferable that the temperature be in the following range, but T _c Since the birefringence is very small at temperatures close to, the upper limit of the ambient temperature is (T _c −10) It is more preferable that the temperature is not higher than C. The polymerizable liquid crystal composition of the present invention may be polymerized in a short-term stable liquid crystal state such as a supercooled state as long as the liquid crystal state is maintained relatively stably during polymerization.
[0036]
The polymer liquid crystal of the present invention may be used while being sandwiched between supports, or may be used after being peeled off from the support.
[0037]
The polymer liquid crystal of the present invention is suitable for an optical element. Examples of the optical element include a retardation film and a polarization hologram element. The polarization hologram element using the polymer liquid crystal of the present invention can exhibit high reciprocation efficiency by utilizing polarization dependency. Therefore, if the polarization hologram element is used as an optical head, an optical head with high light utilization efficiency can be produced.
[0038]
【Example】
Examples 1-3 and 5-8 are Examples, and Example 4 is a comparative example.
[Example 1: Synthesis of compound]
Into a 300 mL flask was placed 18.8 g (0.14 mol) of 4-hydroxybenzoic acid, 95 mL of ethanol, 17.5 g (0.31 mol) of potassium hydroxide, 18 mL of water, and 0.38 g of potassium iodide (.0.1 mol). 16 mol) was added at room temperature, and the mixture was stirred and heated to 60 ° C., and then 29.0 g (0.17 mol) of 6-bromo-1-hexanol was gradually added dropwise. The temperature was further raised, and the reaction was continued for 24 hours while maintaining the reflux state. After cooling to room temperature and distilling off ethanol under reduced pressure, 30 mL of water was added and washed with 10 mL of ether. The ether layer was separated and removed, and 15 mL of 2N hydrochloric acid was added to the aqueous layer to precipitate crystals. The solution was filtered under reduced pressure, and the crystals were collected by filtration. The obtained crystals were dissolved in 1000 mL of tetrahydrofuran in a 1000 mL flask, and dried by adding 5 g of anhydrous magnesium sulfate. The powder crystals obtained by evaporating tetrahydrofuran under reduced pressure were subjected to column chromatography using a column packed with silica gel using ethyl acetate as a developing solution. Ethyl acetate in the fractionated solution was distilled off under reduced pressure, and recrystallization was performed with ethanol to obtain Compound 12, that is, 23.3 g (0.10 mol) of 4- (6-hydroxyhexyloxy) benzoic acid (yield). 70%).
[0039]
Subsequently, a mixture of 2.8 g (12.0 mmol) of the obtained compound, 125 mL of dry tetrahydrofuran and 3.0 g (30 mmol) of triethylamine was placed in a 300 mL flask, and the flask was cooled with ice water. A mixture of 2.7 g of dry tetrahydrofuran and 2.7 g (30 mmol) of acrylic acid chloride was added so that the temperature of the reaction solution did not exceed 5 ° C. After sufficiently reacting, the mixture was filtered under reduced pressure, and tetrahydrofuran in the filtrate was distilled off under reduced pressure. 30 mL of dichloromethane was added to the residue, and this was washed with 30 mL of a 5% by mass aqueous sodium hydrogen carbonate solution. The organic layer was further washed with 25 mL of water, and then the organic layer was dried over 1 g of anhydrous magnesium sulfate. Dichloromethane was distilled off under reduced pressure, and the resulting yellow viscous liquid was developed using a mixed solvent of ethyl acetate and n-hexane (ethyl acetate: n-hexane = 6: 4) as a developing solution and a column packed with silica gel. Column chromatography was performed. The mixed solvent of ethyl acetate and n-hexane in the fractionated solution was distilled off under reduced pressure, and further recrystallized with 5 mL of ethanol to give white crystalline compound 13, that is, 4-((6-acryloyloxy) hexyloxy) benzoic acid. 1.5 g (5.4 mmol) was obtained (45% yield).
[0040]
Add 1.5 g (5.4 mmol) of Compound 13 well dried in a 50 mL flask, 10 mL of dichloromethane, 1.3 g (10.7 mmol) of thionyl chloride and a few drops of N, N-dimethylformamide, Stir at room temperature for 1 hr. Excess thionyl chloride was distilled off under reduced pressure to obtain liquid compound 14, that is, 1.6 g (5.1 mmol) of 4-((6-acryloyloxy) hexyloxy) benzoic acid chloride (yield 94%).
[0041]
Compound 50, 1.1 g (5.0 mmol) of 4-hydroxy ((4′-cyano) phenylethynyl) benzene, 12 mL of dry tetrahydrofuran and 0.61 g (5.9 mmol) of triethylamine were added to a 50 mL flask and mixed. While cooling with ice water, a mixture of 1.6 g (5.1 mol) of compound 14 and 2 mL of dry tetrahydrofuran was added so that the temperature of the reaction solution in the flask did not exceed 5 ° C. After the reaction, the precipitated salt was removed by filtration under reduced pressure, and tetrahydrofuran in the filtrate was distilled off under reduced pressure. To the residue was added 20 mL of dichloromethane. The organic layer was washed with 20 mL of a 5% by mass aqueous sodium hydrogen carbonate solution, and further with 25 mL of water, and the organic layer was dried over anhydrous magnesium sulfate. Dichloromethane was distilled off under reduced pressure to obtain a yellow solid. Column chromatography was performed using a column filled with silica gel using dichloromethane as a developing solution. Dichloromethane in the fractionated solution was distilled off under reduced pressure, and further recrystallized with 5 mL of ethanol to give Compound 15, that is 4-((6-acryloyloxy) hexyloxy) benzoic acid (4-((4′- 1.7 g (3.5 mmol) of cyano) phenylethynyl) phenyl) were obtained (yield 70%).
[0042]
[Chemical 6]

[0043]
The infrared absorption spectrum (KBr tablet) of Compound 15 is shown in FIG.
Also, ¹ H-NMR spectrum (CDCl ₃ Solvent, TMS internal standard) is δ (ppm): 1.43 (4H, m), 1.68 (4H, m), 4.09 (4H, m), 5.92 (1H, d), 6 .15 (1H, dd), 6.31 (1H, d), 7.10 (2H, d), 7.36 (2H, d), 7.72 (4H, m), 7.89 (2H, d), 8.06 (2H, d).
[0044]
As a result of raising the temperature from room temperature while observing the compound 15 with a polarizing microscope, the crystal changed from a crystal to a nematic liquid crystal at 104 ° C., and it was confirmed that it was a nematic liquid crystal up to 160 ° C. Above that temperature, the phase transition temperature from nematic liquid crystal to isotropic liquid could not be confirmed due to polymerization. Further, as described above, after the temperature was raised to 150 ° C., when the temperature was lowered, a phase transition from nematic liquid crystal to crystal was observed at 104 ° C., and it was confirmed that the present compound was an enantiotropic liquid crystal.
[0045]
[Example 3: Birefringence of compound]
T _c Is 85 ° C., and birefringence Δn (X ₀ ) _Ts Liquid crystal monomer X with 0.119 ₀ And the birefringence Δn calculated as follows: _Ts Is defined as the birefringence of the compound. The birefringence is obtained at 589 nm. Liquid crystal monomer X ₀ Liquid crystal composition X in which 10 mol% of compound 15 was dissolved in ₁ Was made. This composition X ₁ T _c Is 105 ° C., and the liquid crystal composition X measured at the temperature Ts obtained by Equation 16 ₁ Birefringence Δn (X ₁ ) _Ts Was 0.142. Δn (X ₀ ) _Ts And Δn (X ₁ ) _Ts Is substituted into Equation 17 and the calculated birefringence Δn of compound 15 is calculated. _Ts Was 0.361.
[0046]
[Chemical 7]

[0047]
[Example 4: Birefringence of compound (comparative example)]
Analogously to Example 3, the birefringence Δn of compound 2 _Ts Was found to be 0.244.
[0048]
As a result of raising the temperature from room temperature while observing Compound 2 with a polarizing microscope, the crystal changed to a nematic liquid crystal at 106 ° C., and it was confirmed that it was a nematic liquid crystal up to 160 ° C. Above that temperature, the phase transition temperature from nematic liquid crystal to isotropic liquid could not be confirmed due to polymerization. In the same manner as described above, when the temperature was raised to 150 ° C. and then the temperature was lowered, the phase transition from nematic liquid crystal to crystal was performed at 106 ° C., and the liquid crystal was an entropic liquid crystal.
[0049]
[Example 5: Preparation of polymer liquid crystal]
20% of compound 15 or 4-((6-acryloyloxy) hexyloxy) benzoic acid (4-((4′-cyano) phenylethynyl) phenyl), compound 18 or 4- ( A composition A comprising 50% (4-acryloyloxybutyl) oxy) -4′-cyanotolane and 30% compound 19, ie 4,4′-di-((4-acryloyloxybutyl) oxy) tolane was prepared. did. Composition A was a nematic liquid crystal having a melting point of 46 ° C. and higher. T _c Was 86 ° C.
[0050]
[Chemical 8]

[0051]
After applying polyimide, which is an alignment agent, with a spin coater and heat-treating, a glass plate rubbed in a certain direction with nylon cloth is used as a support, and the two supports are used with an adhesive so that the surfaces subjected to the alignment treatment face each other. A cell M was manufactured by pasting. At that time, a glass block was inserted on one side to produce a wedge-shaped cell. In the cell M, the wedge apex angle is 1.6 degrees, the dimensions are 17 mm length, and 30 mm width, and the rubbing direction is 180 degrees with respect to the apex direction of the wedge tip.
[0052]
A composition obtained by adding 0.5% by mass of a photopolymerization initiator “Irgacure 907 (manufactured by Ciba Specialty Chemicals)” to composition A was injected into cell M produced as described above at 86 ° C. Next, a wavelength of 365 nm at 50 ° C., 50 mW / cm ² A photopolymerization was carried out by irradiating with ultraviolet rays having the intensity of 60 seconds. After the polymerization, a film-like polymer liquid crystal A was obtained. The polymer liquid crystal A was transparent in the visible range, and no scattering was observed. Δn measured at a temperature of 30 ° C. using light having a wavelength of 589 nm was 0.251.
[0053]
[Example 6 (Example)]
On a disk-shaped glass substrate with a diameter of 75 μm on which a rectangular lattice with a pitch of 10 μm and a depth of 1.4 μm is formed, a polyimide as an aligning agent is applied with a spin coater and heat-treated, and then a nylon cloth is used with respect to the lattice direction. The cell N is bonded to the glass substrate that has been subjected to the rubbing process in the parallel direction and the glass substrate that has been subjected to the alignment process using an adhesive so that the alignment process surfaces face each other and the substrate interval is 2 μm. Produced. At that time, the alignment directions were made parallel.
[0054]
A composition obtained by adding 0.5% by mass of a photopolymerization initiator “Irgacure 907 (manufactured by Ciba Specialty Chemicals)” to composition A was injected into cell N produced as described above at 86 ° C. to form a lattice. The recess was filled with composition A. Next, at 50 ° C., wavelength 365 nm, 50 mW / cm ² A photopolymerization was carried out by irradiating with ultraviolet rays having the intensity of 60 seconds. A quarter wavelength plate was laminated on one surface of the cell N to produce a polarization hologram beam splitter (optical element). When this polarization hologram beam splitter was used as an optical head component, the optical head obtained a light use efficiency of 50% in total of ± first-order diffraction efficiencies with a laser light source having a wavelength of 650 nm.
[0055]
[Example 7 (Example)]
A compound obtained by adding 0.5% by mass of a photopolymerization initiator “Irgacure 907 (manufactured by Ciba Specialty Chemicals)” to Compound 15 was injected into the aforementioned cell M at 110 ° C. Next, at 110 ° C., wavelength 365 nm, 50 mW / cm ² A photopolymerization was carried out by irradiating with ultraviolet rays having the intensity of 60 seconds. After the polymerization, a film-like polymer liquid crystal B was obtained. The polymer liquid crystal B was transparent in the visible range, and no scattering was observed. Δn measured at a temperature of 30 ° C. using light having a wavelength of 589 nm was 0.318.
[0056]
【The invention's effect】
The compound of the present invention is a photopolymerizable liquid crystal monomer that can exhibit liquid crystallinity at high temperatures. That is, when the compound of the present invention is used as a component of the liquid crystal composition, a liquid crystal composition having a high isotropic phase transition temperature can be obtained.
[0057]
When a polymer liquid crystal is prepared using the compound of the present invention, a polymer liquid crystal having a large birefringence can be obtained.
[0058]
Further, the compound of the present invention and the composition using the same can produce a polymer liquid crystal by photopolymerization. This polymer liquid crystal is suitable as an optical element because it does not scatter. The polymer liquid crystal can be used as an optical element for a retardation film, a polarization hologram element and the like, and the polarization hologram element is particularly suitable as an optical head. The present invention can be applied in various ways as long as the effects of the present invention are not impaired.
[Brief description of the drawings]
1 is an infrared absorption spectrum of compound 15. FIG.

Claims (7)

An acrylic acid derivative compound represented by the following formula 1.

R: a hydrogen atom or a methyl group.
S ¹ : each independently represents a single bond, —O—, —COO— or —OCO—.
S ² and S ³ each independently represents a single bond, —COO— or —OCO—.
T ¹ , T ² , T ³ : each independently one or more hydrogen atoms may be substituted with a methyl group, a fluorine atom or a chlorine atom, and / or one or more ═CH— is —N 1,4-phenylene group optionally substituted by =.
U: trifluoromethyl group, trifluoromethoxy group, cyano group, isothiocyanate group, fluorine atom or chlorine atom.
m: An integer from 0 to 8.
n: 0 when m is 0, 1 when m is 1-8.
x, y: each independently 0 or 1, and x + y ≠ 0. The acrylic acid derivative compound according to claim 1, wherein R is a hydrogen atom and U is a cyano group. A liquid crystal composition comprising at least 5% (on a molar basis) of at least one selected from acrylic acid derivative compounds represented by formula (1).

R: a hydrogen atom or a methyl group.
S ¹ : each independently represents a single bond, —O—, —COO— or —OCO—.
S ² and S ³ each independently represents a single bond, —COO— or —OCO—.
T ¹ , T ² , T ³ : each independently one or more hydrogen atoms may be substituted with a methyl group, a fluorine atom or a chlorine atom, and / or one or more ═CH— is —N 1,4-phenylene group optionally substituted by =.
U: trifluoromethyl group, trifluoromethoxy group, cyano group, isothiocyanate group, fluorine atom or chlorine atom.
m: An integer from 0 to 8.
n: 0 when m is 0, 1 when m is 1-8.
x, y: each independently 0 or 1, and x + y ≠ 0. A polymer liquid crystal obtained by polymerizing the liquid crystal composition according to claim 3. The polymer liquid crystal according to claim 4, which is polymerized by irradiation with ultraviolet rays or visible rays. An optical element comprising the polymer liquid crystal according to claim 4 or 5. An optical head using the optical element according to claim 6.

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