JP2004091479A - Maleimide compound, active energy ray-curable composition containing the same, polymer for low refractive index optical material, and method for producing maleimide compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyfunctional maleimide compound containing fluorine, a composition thereof, a polymer for an optical material having a low refractive index and a production method of a polyfunctional maleimide compound having fluorine substituting at a specific position in the molecule thereof. <P>SOLUTION: The composition contains the maleimide compound represented by general formula (1), wherein, X is a 1-10C alkylene or polymethylene group of which part of or all of the hydrogen atoms may be substituted by fluorine atoms; Z is an aliphatic hydrocarbon group that may contain a branching ring, of which at least one hydrogen atom is substituted by fluorine atoms; n is an integer of 2-8. The polymer for an optical material having a low refractive index is obtained by curing the above composition and has a refractive index of 1.47 or less. The method for producing the maleimide compound containing a fluorine atom comprises dropping pyridine into the reactor in the reaction of an acid halide of maleimidacetic acid and a compound in which a fluorine atom binds to a methylene group in the β-position of a hydroxy group. <P>COPYRIGHT: (C)2004,JPO

Description

（式中、Ｘは、一部または全部の水素原子がフッ素原子で置換されていてもよい炭素数１〜１０のアルキレン基またはポリメチレン基を表す。複数存在するＸはそれぞれ同じでも異なっていても良い。Ｚは、Ｚ_１又はＺ_２−（Ｚ_３）_ｍを表し、Ｚ_１は、一つ以上の水素原子がフッ素原子で置換された炭素数１〜７０のｎ価の脂肪族炭化水素基（但し、置換基として、フッ素原子をもたない１つ以上のメチレン基は、酸素原子が互いに隣接しないものとして、−Ｏ−、−ＣＯ−、−ＯＣＯ−、−ＣＯ−Ｏ−、−ＮＨＣＯ−Ｏ−又は―ＯＣＯＮＨ―で置換されていてもよい。）を表し、Ｚ_２は、２〜８個の遊離原子価を有するイソシアヌル環、ベンゼン環、ナフタレン環、テトラヒドロフラン環、デカヒドロナフタレン環、ノルボルネン環、又はシクロヘキサン環を表し、Ｚ_３は、一つ以上の水素原子がフッ素原子で置換された炭素数１〜７０の２価の脂肪族炭化水素基（但し、置換基として、フッ素原子をもたない１つ以上のメチレン基は、酸素原子が互いに隣接しないものとして、−Ｏ−、−ＣＯ−、−ＯＣＯ−、−ＣＯ−Ｏ−、−ＮＨＣＯ−Ｏ−又は―ＯＣＯＮＨ―で置換されていてもよい。）を表し、ｍはＺ_２が有する遊離原子価と同じ整数を表し、ｎは２〜８の整数を表す。）
【００１２】
また、本発明は、一般式（１）で表されるマレイミド化合物を含有する活性エネルギー線硬化性組成物を提供する。
【００１３】
また、本発明は、前記記載の活性エネルギー線硬化性組成物を重合して得られ、屈折率が１．４７以下である低屈折光学材料用重合体を提供する。
【００１４】
また、本発明は、反応容器中で、マレイミド酢酸の酸ハロゲン化物と、ヒドロキシ基のβ位メチレン基にフッ素原子が結合しているアルコール化合物とを反応させる際、反応が生じる温度条件下で、該反応容器中にピリジン又はピリジン誘導体を滴下する、フッ素原子を含有するマレイミド化合物の製造方法を提供する。
【００１５】
【発明の実施の形態】
一般式（１）で表されるマレイミド化合物の説明
一般式（１）で表されるマレイミド化合物は、マレイミドカルボン酸と、ポリオールとを反応させて得られる。以下にその反応の一例を示す。
【００１６】
【化５】

【００１７】
式中、（ａ）はマレイミドカルボン酸を表し、（ｂ）はポリオールを表し、（ｃ）は本発明の一般式（１）で表されるマレイミド化合物を表す。
【００１８】
一般式（１）において、Ｘは、一部または全部の水素原子がフッ素原子で置換されていてもよい炭素数１〜１０のアルキレン基またはポリメチレン基を表す。複数存在するＸはそれぞれ同じでも異なっていても良い。
Ｘを部分構造に有するマレイミドカルボン酸（ａ）としては、例えば、マレイミド酢酸、マレイミドプロピオン酸、マレイミド酪酸、マレイミドカプロン酸、あるいはマレイミドウンデカン酸などがあげられる。Ｘの鎖長が長いほど、マレイミド化合物単位質量あたりのマレイミド基数が少なくなるために最終的に得られる硬化物の架橋密度が低くなり、また、Ｘを構成するアルキレン基またはポリメチレン基の水素原子のフッ素原子への置換率が低い場合は、マレイミド化合物としてのフッ素原子含有量も低下することから、本発明において使用するマレイミドカルボン酸としては、Ｘが最も短い、マレイミド酢酸が好ましい。
これらのマレイミドカルボン酸はジャーナル・オブ・アプライド・ポリマー・サイエンス　第５７巻　２１９頁（１９９５年）やジャーナル・オブ・オーガニック・ケミストリー　第６２巻　２６５２頁（１９９７年）に開示されているような公知の方法で合成することができる。
【００１９】
一般式（１）において、ｎ、即ちマレイミド基の数は２〜８であり、２〜４が更に好ましい。高い強度を有するコーティング剤としては官能基数が多い方が有利であるが、一般的に入手が容易なフッ素含有ポリオールがジオールであり、多官能化に際してフッ素原子を有さない核となる化合物を用いなければならない等化合物の低屈折率化には不利となることから、ｎが２であることが望ましい。
【００２０】
一般式（１）において、Ｚ_１は、一つ以上の水素原子がフッ素原子で置換された炭素数１〜７０のｎ価の脂肪族炭化水素基（但し、置換基としてフッ素原子をもたない１つ以上のメチレン基は、酸素原子が互いに隣接しないものとして、−Ｏ−、−ＣＯ−、−ＯＣＯ−、−ＣＯ−Ｏ−、−ＮＨＣＯ−Ｏ−又は―ＯＣＯＮＨ―で置換されていてもよい。）であり、Ｚ_３は、一つ以上の水素原子がフッ素原子で置換された炭素数１〜７０の２価の脂肪族炭化水素基（但し、置換基としてフッ素原子をもたない１つ以上のメチレン基は、酸素原子が互いに隣接しないものとして、−Ｏ−、−ＣＯ−、−ＯＣＯ−、−ＣＯ−Ｏ−、−ＮＨＣＯ−Ｏ−又は―ＯＣＯＮＨ―で置換されていてもよい。）である。脂肪族炭化水素基は非環式が好ましく、一部環式を含んでいてもよい。また炭素数が７０以上となると架橋点間距離が長くなりすぎ、材料の強度が低下するので好ましくない。
中でも、一つ以上の水素原子がフッ素原子で置換された炭素数１〜４０の二価のアルキレン基またはポリメチレン基、あるいはそれらが−Ｏ−（エーテル結合）でつながった二価の基が好ましい。これらの構造においては、原料が比較的入手しやすいうえに、屈折率を上げる要因が最も少なくなる。特に、該アルキレン基またはポリメチレン基がエーテル結合で繋がった二価の基は、フッ素原子で置換されたアルキレン基またはポリメチレン基より、同じフッ素含有量でも低屈折率化できる場合が多く特に好ましい。
【００２１】
Ｚ_１を部分構造に有するｎ＝２のポリオール（ｂ）としては、例えば、２，２，３，３，４，４，−ヘキサフルオロ−１，５−ペンタンジオール、２，２，３，３，４，４，５，５−オクタフルオロ−１，６−ヘキサンジオール、２，２，３，３，４，４，５，５，６，６，７，７−ドデカフルオロ−１，８−オクタンジオールなどのパーフルオロアルキルジオール；パーフルオロトリエチレングリコール、パーフルオロテトラエチレングリコールなどのパーフルオロアルキレングリコール；α−（１，１−ジフルオロ−２−ヒドロキシエチル）−ω−（２，２−ジフルオロエタノール）ポリ（オキシ−１，１，２，２−テトラフルオロエチレン）、α−（１，１−ジフルオロ−２−ヒドロキシエチル）−ω−（２，２−ジフルオロエタノール）ポリ（オキシ−ジフルオロメチレン）、α−（１，１−ジフルオロ−２−ヒドロキシエチル）−ω−（２，２−ジフルオロエタノール）ポリ（オキシ−ジフルオロメチレン）（オキシ−１，１，２，２−テトラフルオロエチレン）などのポリパーフルオロアルキレンエーテルジオール；３−パーフルオロブチル−１，２−エポキシプロパン、３−パーフルオロオクチル−１，２−エポキシプロパン、３−パーフルオロブチル−１，２−エポキシプロパンなどのフルオロアルキルエポキシドの開環ジオール；２，２−ビス（４−ヒドロキシシクロヘキシル）ヘキサフルオロプロパン等があげられる。また、これらのフッ素含有ジオールにエチレンオキシドやプロピレンオキシドといったアルキレンオキシドを付加させたジオールを用いることもできる。
【００２２】
また、Ｚ_１を部分構造に有するｎ≧３のポリオール（ｂ）としては、１，１，１−トリス（２，２，３，３，４，４，５，５−オクタフルオロ−６−ヒドロキシヘキシルオキシメチル）エタン、１，１，１−トリス（２，２，３，３，４，４，５，５−オクタフルオロ−６−ヒドロキシヘキシルオキシメチル）プロパン、１，１，１−トリス（２，２，３，３，４，４，５，５，６，６−デカフルオロ−８−ヒドロキシオクチルオキシメチル）プロパン、２，２−ビス（２，２，３，３，４，４，５，５−オクタフルオロ−６−ヒドロキシヘキシルオキシメチル）−１，３−ビス（２，２，３，３，４，４，５，５−オクタフルオロ−６−ヒドロキシヘキシルオキシ）プロパン、１−（２，２，３，３，４，４，５，５−オクタフルオロ−６−ヒドロキシヘキシルオキシ）−３−［３−（２，２，３，３，４，４，５，５−オクタフルオロ−６−ヒドロキシヘキシルオキシ）−２，２−ビス（２，２，３，３，４，４，５，５−オクタフルオロ−６−ヒドロキシヘキシルオキシメチル）プロポキシ］−２，２−ビス（２，２，３，３，４，４，５，５−オクタフルオロ−６−ヒドロキシヘキシルオキシメチル）プロパン等といったフッ素含有ポリオールや、それらにエチレンオキシドやプロピレンオキシドといったアルキレンオキシドを付加させたポリオールを用いることもできる。
【００２３】
Ｚ_２−（Ｚ_３）_ｍを部分構造に有する環状構造を有するポリオール（ｂ）としては、例えば、ヘキサメチレンジイソシアネート３量体、やトリス（２−カルボキシエチル）イソシアヌレートに上述のＺ_１にあげたようなフッ素含有ジオールを反応させたイソシアヌル環を有するトリオールやシクロヘキサン―１，２，４−トリカルボン酸、シクロヘキサン―１，２，４，５−テトラカルボン酸、トリメリト酸、ピロメリト酸、ナフタレン−２，３，６，７−テトラカルボン酸、ナフタレン−１，４，５，８−テトラカルボン酸、デカヒドロナフタレン−１，４，５，８−テトラカルボン酸、デカヒドロナフタレン−１，２，３，４，５，６，７，８−オクタカルボン酸、テトラヒドロフラン―２，３，４，５―テトラカルボン酸、２，３，５，６−ノルボルネン四酢酸や４，４’−（ヘキサフルオロイソプロピリデン）ジフタル酸、に上述のＺ_１にあげたようなフッ素含有ジオールを反応させた、シクロヘキサン環、ナフタレン環、デカヒドロナフタレン環、テトラヒドロフラン環、ノルボルネン環やベンゼン環を有する３〜８官能の多官能アルコールがあげられる。Ｚ_２で表されるイソシアヌル環、ベンゼン環、ナフタレン環、デカヒドロナフタレン環、テトラヒドロフラン環、ノルボルネン環、シクロヘキサン環は、マレイミド基数を増やすための分岐部位であり、該部位にもフッ素原子が含有されていることが好ましいが、原料の入手が困難な場合が多く、一般的にはフッ素を有していないので屈折率が上がる要因となる。しかし、特に高い強度が要求される用途においては、架橋点間距離を短くすることができることから有利となる。
【００２４】
本発明のマレイミド化合物中のフッ素含有量は多い方が良く、好ましくは２５％以上であり、より好ましくは３０％以上である。また、同じフッ素含有量でも、Ｚ_１又はＺ_３が、フッ素で置換されたアルキレン基またはポリメチレン基であるよりも、−Ｏ−（エーテル結合）を有する基である方が、より低屈折率化できる場合が多い。
【００２５】
一般式（２）、（３）で表されるマレイミド化合物の説明
一般式（１）で表される化合物の中でも、下記一般式（２）で表される化合物は、特に低屈折率であり好ましい。
【００２６】
【化６】

【００２７】
式中、Ｘ_１及びＸ_２はそれぞれ独立して、一部または全部の水素原子がフッ素原子で置換されていてもよい炭素数１〜１０のアルキレン基またはポリメチレン基を表し、ｒは１〜２０の整数を表す。
【００２８】
一般式（２）で表される化合物は、屈折率が高くなる構成要素が殆どなく、屈折率を低くするフッ素原子の含有率が高くなるため、得られる硬化物の屈折率が低くなる。ｒが大きくなるほど活性エネルギー線硬化性組成物の粘度が高くなる傾向がある。
【００２９】
また、一般式（１）で表される化合物の中でも、下記一般式（３）で表される化合物は、活性エネルギー線硬化性組成物の粘度が低く抑えられ、かつ屈折率の低い硬化物が得られ好ましい。
【００３０】
【化７】

【００３１】
式中、Ｘ_１及びＸ_２はそれぞれ独立して、一部または全部の水素原子がフッ素原子で置換されていてもよい炭素数１〜１０のアルキレン基またはポリメチレン基を表し、ｐ、ｑは等しくても異なってもよい０〜２０の整数であり、かつｐ＋ｑは１〜２０である。ここで、ｐおよびｑで表される整数は、それぞれのカッコでくくられた単位の数の比を表しており、アルコール残基中における各単位の配列はランダムであってもよい。
一般式（１）〜（３）で表される化合物の好ましい態様を以下に示す。
【００３２】
【化８】

【００３３】
【化９】

【００３４】
【化１０】

ポリ（パーフルオロアルキレンエーテル）ジオール分子量：１０００、１５００、２０００
【００３５】
【化１１】

ポリ（パーフルオロアルキレンエーテル）ジオール分子量：１０００、１５００、２０００
【００３６】
【化１２】

【００３７】
合成方法
一般式（１）で表される化合物のうち、フッ素原子を含有するアルコールとして、ヒドロキシ基から、そのδ位メチレン基より遠い位置にフッ素原子を有していたり、フッ素原子を有しないアルキレンオキシド等で末端変性されているアルコールを用いる場合は、公知の方法、例えば、マレイミドカルボン酸とアルコールとの脱水縮合反応、マレイミドカルボン酸の酸ハロゲン化物とアルコールとの脱ハロゲン化水素反応、あるいはマレイミドカルボン酸エステルとアルコールとのエステル交換反応など、公知のエステル合成反応によって製造することができる。エステル合成反応に際しては、酸触媒、脂肪族または芳香族スルホン酸、有機錫化合物、金属ハロゲン化物、金属酸化物等、公知慣用のエステル化触媒、あるいはエステル交換触媒、脱ハロゲン化水素反応においてはトリエチルアミン、ピリジン、コリジンなどの公知慣用のハロゲン化水素スカベンジャーを使用することができる。エステル合成反応中にマレイミド基が熱重合するのを防止するためには、ヒドロキノンや４−ｔｅｒｔ−ブチルカテコールなど公知慣用の重合禁止剤を使用してもよい。
【００３８】
一般式（２）と（３）で表される化合物等では、フッ素原子を含有するアルコールとして、ヒドロキシ基のβ位メチレン基にフッ素原子が結合しているアルコール化合物を使用するが、これは、公知の方法では反応しない。本発明者らは、反応容器中で、マレイミド酢酸の酸ハロゲン化物と、ヒドロキシ基のβ位メチレン基にフッ素原子が結合しているアルコール化合物とを反応させる際、反応が生じる温度条件下で、該反応容器中にピリジン又はピリジン誘導体を滴下すれば、反応が進むことを見出した。
【００３９】
本反応で用いることができる塩基はピリジン又はピリジン誘導体である。本反応は反応性の低いヒドロキシ基のβ位メチレン基にフッ素原子が結合しているアルコール化合物を用いる為に比較的高い反応温度が必要となり、このような条件下で強い塩基を用いるとマレイミド部位の重合等が生じる。また、ピリジン又はピリジン誘導体を、反応が生じうる条件下で滴下することにより、はじめて反応が進行する。この原因は明確になっていないが、ヒドロキシ基のβ位メチレン基にフッ素原子が結合しているアルコール化合物の比較的強い酸性に起因するものと推測している。
本反応で用いられるピリジン誘導体を例示すると、ピコリン、エチルピリジン、ルチジン、コリジン等のアルキル基を有するピリジン、クロロピリジン、ジクロロピリジン等のハロゲンを有するピリジン、キノリン、イソキノリン等の窒素含有複素芳香族化合物があげられる。
【００４０】
本反応で使用されるピリジン又はピリジン誘導体の量は、反応により発生するハロゲン化水素に対して当量以上であれば良いが、あまり多くても経済的でなく、該ハロゲン化水素に対して１〜２当量程度が好ましい。
本反応におけるピリジン又はピリジン誘導体の滴下による添加は、ヒドロキシ基のβ位メチレン基にフッ素原子が結合しているアルコール化合物とマレイミド酢酸の酸ハロゲン化物の反応が生じうる温度条件下で行われ、また、反応の進行に応じて滴下されることが好ましい。この反応が生じうる温度条件はヒドロキシ基のβ位メチレン基にフッ素原子が結合しているアルコール化合物やマレイミド酢酸の酸ハロゲン化物の構造や反応に用いられる溶媒等に依存する為、好適な範囲を一概には示すことは難しいが、おおよそ６０〜１５０℃程の範囲である。また、適切な滴下速度も反応速度に影響を与える基質の構造、溶媒や反応温度により変化する為、好適な範囲を一概には示すことは難しいが、３０分から数時間程度の範囲である。
本反応で使用される反応溶媒は、本反応に影響を及ぼさない限りにおいていかなる溶媒も用いることができる。使用するアルコール化合物の構造にもよるが、反応が生じる温度で該アルコール化合物を均一に溶解しうる溶媒を使用することが好ましい。このような溶媒を例示すると、トルエン、メチルエチルケトン、酢酸エチル、ジメチルホルムアミド、ジメチルアセトアミド、Ｎ−メチルピロリドンなどがあげられる。
また、本反応に際しても上述のフッ素原子を含有するアルコールとしてヒドロキシ基のδ位メチレン基より遠い位置にフッ素原子を有していたり、フッ素原子を有しないアルキレンオキシドで末端変性されているアルコールを用いる場合の反応と同様に重合禁止剤を用いることもできる。
【００４１】
活性エネルギー線硬化性組成物
本発明のマレイミド化合物は、単独で、あるいは、共重合可能な重合性化合物を添加して、活性エネルギー線硬化性組成物として使用する。このような重合性化合物としては、たとえば、（メタ）アクリル酸、（メタ）アクリル酸エステル類、スチレンなど、マレイミド化合物と共重合可能な公知の単量体、あるいはウレタン（メタ）アクリレートなどの、重合性官能基を有するオリゴマーが挙げられる。
また、本発明のマレイミド化合物を開始剤として用い、フッ素原子を有する（メタ）アクリル酸エステル等の低屈折材料を硬化することも可能である。
【００４２】
本発明のマレイミド化合物は、それ自身が重合開始剤として作用するので、本発明の活性エネルギー線硬化性組成物には、重合開始剤を添加する必要はないが、活性エネルギー線硬化性組成物中の本発明のマレイミド化合物の含有率が極端に低い場合や、高い重合速度を必要とする場合には、通常の熱重合あるいは活性エネルギー線重合の場合と同様に、公知慣用の熱重合開始剤や光重合開始剤を使用してもよい。しかしながら、得られる重合体を光学材料などに使用する場合には、活性エネルギー線硬化性組成物中に含有される重合性化合物全量に対して０〜１％の範囲で使用するのが好ましい。添加率が１質量％を超えた場合には、重合体中に残存する未反応の重合開始剤や、その分解生成物が、硬化時の臭気の発生や、硬化物の耐光性低下の原因となりやすい。
【００４３】
本発明の活性エネルギー線硬化性組成物には、ヒドロキノンや４−ｔｅｒｔ−ブチルカテコールなど公知慣用の重合禁止剤や、アセトン、トルエン、酢酸エチル、クロロホルム、あるいはジクロロメタンなどの溶剤を添加することもできる。
【００４４】
本発明の活性エネルギー線硬化性組成物は、紫外線や電子線等の活性エネルギー線照射により硬化させることができる。中でも紫外線が好ましい。紫外線の光源としては、低圧水銀ランプ、高圧水銀ランプ、超高圧水銀ランプ、メタルハライドランプ、ケミカルランプ、ブラックライトランプ、水銀−キセノンランプ、エキシマランプ、ショーアーク灯、ヘリウム・カドミウムレーザー、アルゴンレーザー、エキシマレーザーなどを使用することができる。
【００４５】
また、本発明の活性エネルギー線硬化性組成物は、熱硬化させることもできる。このときの熱源は特に限定なく、公知の熱源が使用できる。また、この場合も、重合開始剤なしで硬化させることができるが、必要に応じて前記公知慣用の熱重合開始剤を添加してもよい。
【００４６】
本発明の活性エネルギー線硬化性組成物を、光学部品あるいはそのコーティング剤、接着剤、または反射防止剤などの低屈折率光学材料として使用する場合には、最終的に得られる重合体の屈折率は１．４７以下であるのが好ましい。このような低屈折率を有する重合体を得るためには、活性エネルギー線硬化性組成物に、本発明のマレイミド化合物との共重合性を有し、分子中にフッ素原子を有する（メタ）アクリル系単量体を配合するとよい。フッ素原子を有する（メタ）アクリル系単量体としては、例えば２，２，３，３，３−ペンタフルオロエチルアクリレート、２−（パーフルオロオクチル）エチルアクリレート、２，２，３，３，３−ペンタフルオロエチルメタクリレート、２−（パーフルオロオクチル）エチルメタクリレート等の単官能モノマーや、２，２，３，３，４，４，−ヘキサフルオロ−１，５−ペンタンジオール、２，２，３，３，４，４，５，５−オクタフルオロ−１，６−ヘキサンジオール　、２，２，３，３，４，４，５，５，６，６，７，７−ドデカフルオロ−１，８−オクタンジオールなどのパーフルオロアルキルジオール；パーフルオロトリエチレングリコール、パーフルオロテトラエチレングリコールなどのパーフルオロアルキレングリコール；α−（１，１−ジフルオロ−２−ヒドロキシエチル）−ω−（２，２−ジフルオロエタノール）ポリ（オキシ−１，１，２，２−テトラフルオロエチレン）、α−（１，１−ジフルオロ−２−ヒドロキシエチル）−ω−（２，２−ジフルオロエタノール）ポリ（オキシ−ジフルオロメチレン）、α−（１，１−ジフルオロ−２−ヒドロキシエチル）−ω−（２，２−ジフルオロエタノール）ポリ（オキシ−ジフルオロメチレン）（オキシ−１，１，２，２−テトラフルオロエチレン）などのポリパーフルオロアルキレンエーテルジオール等のジオールのジアクリレートやジメタクリレートがあげられる。
【００４７】
【実施例】
以下に、実施例および比較例を用いて本発明をさらに具体的に説明する。特に断らない限り、「部」および「％」はそれぞれ「質量部」および「質量％」を表す。
【００４８】
（合成例１）　マレイミド酢酸の合成
撹拌機、温度計、滴下ロート、ディーンスターク分留器及び冷却管を備えた反応容器に、トルエン１４００部、ｐ−トルエンスルホン酸一水和物５２部及びトリエチルアミン２８部を順次仕込み、撹拌しながら無水マレイン酸３００部を加えた後、３０℃まで昇温させながら溶解させた。さらにグリシン２３０部を加えた後、撹拌しながら７０℃で３時間反応させた。その後、さらにトルエン５００部、トリエチルアミン６００部を加え、溶媒を加熱還流させて生成する水を除去しながら１時間反応させた。反応混合物から溶媒を留去して得られた残留物に、４ｍｏｌ／ｄｍ^３塩酸を加えてｐＨ２に調整した後、加熱−再結晶して、マレイミド酢酸の淡黄色固体７３部を得た。
【００４９】
（合成例２）　マレイミド酢酸クロライドの合成
滴下ロート、攪拌機、温度計、窒素導入管および水酸化ナトリウム水溶液トラップを備えた反応容器に、マレイミド酢酸２０部およびトルエン２００部を仕込み、撹拌しながら、室温下、塩化チオニル５０部を滴下した。滴下終了後、反応混合物を５０℃まで加熱し、撹拌下、５時間反応させた。冷却後、反応混合物を減圧蒸留し、マレイミド酢酸クロライド２０部を得た。
【００５０】
（合成例３）　トリス（２−カルボキシエチル）イソシアヌレートの酸クロライドの合成
冷却装置、滴下ロート、攪拌機、温度計を備えた反応容器に四国化成製１，３，５−トリス（２−カルボキシエチル）イソシアヌレート１２０部、ジメチルホルムアミド４５０部を仕込み、２０℃まで冷却した。冷却装置を止めた後に、２時間かけて塩化チオニル１４６部を滴下ロートから加えた。滴下終了後さらに２時間攪拌した後、攪拌を止めて再び反応器を冷却した。１５℃まで冷却し、生成した固体を吸引ろ過によりろ別した。固体はクロロホルム５０部で洗浄した後、減圧乾燥し、１，３，５−トリス（２−カルボキシエチル）イソシアヌレートの酸クロライド１２０部（白色固体）を得た。
【００５１】
（実施例１）
マレイミド酢酸クロライド１７５部、ダイキン化成品販売社製２，２，３，３，４，４，５，５−オクタフルオロヘキサン−１，６−ジオール「Ａ−７４１２」１００部、ｐ−メトキシフェノール１．４部、トルエン２５００部を反応容器に仕込み、攪拌しながら１００℃まで昇温後、２時間同温度を保持した。次いで、ピリジン５８部を３０分かけて滴下し、さらに２時間同温度を保持した。反応混合物からトルエンを留去し、残査を酢酸エチル／トルエン混合溶剤に溶解、再結晶化させた後、脱溶剤して２，２，３，３，４，４，５，５−オクタフルオロヘキサン−１，６−ジオールのビスマレイミド酢酸エステル［マレイミド化合物（１−１）］２０部を得た。
^１Ｈ　ｎｍｒ（ＣＤ_３ＣＯＣＤ_３）　δ７．００（一重線、４Ｈ）、δ４．４０（一重線、４Ｈ）、δ４．７５（多重線、４Ｈ）
【００５２】
得られたマレイミド化合物（１−１）を使用し、下記組成の活性エネルギー線硬化性組成物を調製した。
マレイミド化合物（１−１）　　　　　　　　　　　　　　　　　８０部
メタクリル酸メチル（以下、「ＭＭＡ」と略記する。）　　　　　２０部
Ｎ，Ｎ−ジメチルホルムアミド　　　　　　　　　　　　　　　９００部
【００５３】
（実施例２）
マレイミド酢酸クロライド９４部、下記一般式（４）で表されるアウジモント社製フッ素含有ジオール「ＦＬＵＯＲＯＬＩＮＫ　Ｄ１０」１００部、ｐ−メトキシフェノール１．０部、トルエン２５００部を反応容器に仕込み、攪拌しながら１００℃まで昇温し、２時間同温度を保持した。
【００５４】
【化１３】

（ｐ、ｑは整数で不定であり、種々の値を有するものの混合物。ＮＭＲにより測定した数平均分子量１０００）
【００５５】
次いで、ピリジン３１部を３０分かけて滴下し、さらに２時間同温度を保持した。反応混合物からトルエンを留去し、残査を酢酸エチルに溶解、再結晶化させた後、脱溶剤して、下記一般式（４）で表されるフッ素含有ジオールの、ビスマレイミド酢酸エステル［マレイミド化合物（１−２）］２０部を得た。
^１Ｈ　ｎｍｒ（ＣＤ_３ＣＯＣＤ_３）　δ６．８５（一重線、４Ｈ）、δ４．４０（一重線、４Ｈ）、δ４．６８（多重線、４Ｈ）
【００５６】
実施例１におけるマレイミド化合物（１−１）の代わりに、マレイミド化合物（１−２）を使用した以外は実施例１と同様にして、活性エネルギー線硬化性組成物を調製した。
【００５７】
（実施例３）
下記一般式（５）で表されるアウジモント社製フッ素含有ジオール「ＦＬＵＯＲＯＬＩＮＫ　Ｅ１０」３００部、トリエチルアミン１４部およびトルエン３０００部を反応容器に加え、室温下、撹拌しながら合成例３で得られたトリス（２−カルボキシエチル）イソシアヌレートの酸クロライド１６部とトルエン５０部からなる溶液を滴下した。
【００５８】
【化１４】

（ｕ、ｖは整数で平均１〜２。ｓ、ｔは整数で不定であり、種々の値を有するものの混合物。ＮＭＲにより測定した数平均分子量１０００）
【００５９】
滴下終了後、反応混合物を５０℃に加熱し、５時間反応させた。冷却後、酢酸エチルで希釈し、濾過により、トリエチルアミンの塩酸塩を除去した。酢酸エチルを減圧下で留去し、得られた混合物をカラムクロマトグラフィーで分離し、目的化合物であるトリス（２−カルボキシエチル）イソシアヌレートの３モルＦＬＵＯＲＯＬＩＮＫ　Ｅ１０エステル体（中間化合物Ａ）４０部を得た。
得られた中間化合物Ａ　３３部、トルエン１００部、ｐ−メトキシフェノール０．３部およびピリジン５部を反応容器に加え、撹拌しながら、室温下、マレイミド酢酸の酸クロライド２６部およびトルエン２０部からなる溶液を滴下した。滴下終了後、反応混合物を９０℃まで加熱して１０時間反応させた。反応混合物からトルエンを留去し、残査をカラムクロマトグラフィーにより精製し、中間体化合物Ａの３つのヒドロキシ基がマレイミド酢酸によりエステル化された［マレイミド化合物（１−３）］５部を得た。
^１Ｈ　ｎｍｒ（ＣＤ_３ＣＯＣＤ_３）　δ６．９５（一重線、６Ｈ）、δ４．４０（一重線、６Ｈ）、δ４．６０（多重線、１４Ｈ）、δ３．９０（多重線、１４Ｈ）、δ３．６０（多重線、１８Ｈ）、δ２．５５（三重線、６Ｈ）
【００６０】
得られたマレイミド化合物（１−３）を使用し、下記組成の活性エネルギー線硬化性組成物を調製した。
マレイミド化合物（１−３）　　　　　　　　　　　　　　　　　６０部
化合物（比−１）　　　　　　　　　　　　　　　　　　　　　　４０部
Ｎ，Ｎ−ジメチルホルムアミド　　　　　　　　　　　　　　　９００部
【００６１】
（比較例１）
ダイキン化成品販売社製２，２，３，３，４，４，５，５−オクタフルオロヘキサン−１，６−ジオール「Ａ−７４１２」１００部、ピリジン６７部およびｐ−メトキシフェノール１．０部を反応容器に仕込み、攪拌しながら、室温下、アクリル酸クロライド９２部を滴下した。滴下終了後、反応混合物を１００℃まで昇温し、５時間同温度を保持した。反応混合物をカラムクロマトグラフィーにより精製して２，２，３，３，４，４，５，５−オクタフルオロヘキサン−１，６−ジオールのジアクリル酸エステル［化合物（比−１）］１４部を得た。
【００６２】
得られた化合物（比−１）を使用し、下記組成の活性エネルギー線硬化性組
成物を調製した。
化合物（比−１）　　　　　　　　　　　　　　　　　　　　　　８０部
ＭＭＡ　　　　　　　　　　　　　　　　　　　　　　　　　　　２０部
Ｎ，Ｎ−ジメチルホルムアミド　　　　　　　　　　　　　　　９００部
【００６３】
（比較例２）
得られた化合物（比−１）を使用し、下記組成の活性エネルギー線硬化性組
成物を調製した。

【００６４】
（比較例３）
撹拌機、温度計、ディーンスターク分留器及び冷却管を備えた反応容器にマレイミド酢酸１５５部、ダイキン化成品販売社製２，２，３，３，４，４，５，５−オクタフルオロヘキサン−１，６−ジオール「Ａ−７４１２」１００部、ｐ−メトキシフェノール１．４部、ｐ−トルエンスルホン酸７．２部およびトルエン２５００部を仕込み、攪拌しながら、加熱し、反応により発生する水を除去すべく、１６時間還流させたが、エステル化反応は起こらなかった。
【００６５】
（比較例４）
マレイミド酢酸ブチル２１１部、ダイキン化成品販売社製２，２，３，３，４，４，５，５−オクタフルオロヘキサン−１，６−ジオール「Ａ−７４１２」１００部、ｐ−メトキシフェノール１．４部、ジブチル錫オキシド６．２部、トルエン２５００部を反応容器に仕込み、攪拌しながら、加熱し、還流させた。反応により生成するブタノールを除去すべく、時間あたり６０部のトルエンを留去し、新たなトルエン６０部を加えながら、反応を２０時間続けたが、エステル交換反応は起こらなかった。
【００６６】
（比較例５）
ダイキン化成品販売社製２，２，３，３，４，４，５，５−オクタフルオロヘキサン−１，６−ジオール「Ａ−７４１２」１００部、ピリジン６７部およびｐ−メトキシフェノール１．０部を反応容器に仕込み、攪拌しながら、室温下、マレイミド酢酸の酸クロライド１７５部を滴下した。滴下終了後、反応混合物を１００℃まで昇温し、５時間同温度を保持したが、目的のエステル体は得られなかった。
【００６７】
（活性エネルギー線硬化性組成物塗膜の硬化性試験）
実施例および比較例で調製した活性エネルギー線硬化性組成物を硬化後の塗膜厚が１０μｍとなるよう、バーコーターでガラス板に塗布し、アイグラフィックス社製ＵＶ照射装置を使用して、照射量が３ｋＪ／ｍ^２となるよう紫外線を照射した。その後、まず５０℃、常圧で、続いて５０℃、１３３Ｐａの減圧下、乾燥機中でＮ，Ｎ−ジメチルホルムアミドを揮発させた。得られた硬化塗膜について、官能検査によって臭気の有無を調べ、指触検査によって硬化の度合いを調べた。実用的な硬化度合いが得られた場合を○、実用的な硬化度合いが得られなかった場合を×と評価した。
【００６８】
（屈折率測定）
実施例および比較例で調製した活性エネルギー線硬化性組成物を、厚さ６ｍｍのガラス板上に、硬化後の塗膜厚が０．０５〜１．０μｍとなるようにバーコーターで塗布後、アイグラフィックス社製ＵＶ照射装置を使用して、照射量が３ｋＪ／ｍ^２となるよう紫外線を照射した。その後、まず５０℃、常圧で、続いて５０℃、１３３Ｐａの減圧下、乾燥機中でＮ，Ｎ−ジメチルホルムアミドを揮発させた。得られた硬化塗膜をガラス板から剥離することなく、フォトデバイス社製エリプソメーター「ＭＡＲＹ−１０２ＭＭ」を使用し、６３２．８ｎｍの光に対する上記硬化塗膜の屈折率を測定した。
【００６９】
（耐候性試験）
前記（活性エネルギー線硬化性組成物塗膜の硬化性試験）において得られた活性エネルギー線硬化性組成物の硬化塗膜について、ダイプラ・ウィンテス社製メタルウエザー耐候性試験機を使用して、窒素雰囲気下、光照射量１８０Ｊ／ｃｍ^２・ｈｒで４時間、次いで光を照射しない状態で４時間放置の繰り返しを１１サイクル行い、目視検査によってブリードアウトの有無を調べた。ブリードアウトが観察されなかった場合を○、ブリードアウトが観察された場合を×と評価した。
【００７０】
【表１】
（表１）

光重合開始剤：チバスペシャリティーケミカルズ社製イルガキュアー１８４
【００７１】
この結果、実施例１、２は、臭気もなく耐候性に優れ、屈折率が１．４７以下の塗膜が得られた。実施例３は、本発明のマレイミド化合物にフッ素原子を有するアクリルモノマーを添加した例であるが、光重合開始剤なしでも硬化し、塗膜特性に問題はなかった。フッ素原子を有するアクリルモノマーを使用した例は、光重合開始剤を使用しないと硬化せず（比較例１）、光重合開始剤を使用すると臭気及び耐候性が悪かった（比較例２）。
【００７２】
【発明の効果】
本発明のマレイミド化合物は、光重合開始剤を全く添加しないか、あるいは添加してもごく微量で、良好に光硬化し、耐久性や強度に優れた硬化物が得られる。
また、これらのマレイミド化合物のうち、従来法では合成できなかった低屈折コーティング材料として有用な、フッ素原子含有量が高く、架橋点間距離の短い多官能マレイミド化合物は、マレイミド酢酸の酸ハロゲン化物と、ヒドロキシ基のβ位メチレン基にフッ素原子が結合しているアルコール化合物とを反応させる際、反応が生じる温度条件下で、該反応容器中にピリジン又はピリジン誘導体を滴下することで合成することができる。
【００７３】
また、本発明のマレイミド化合物を含有する活性エネルギー線硬化性組成物を光硬化させて得られる屈折率１．４７以下の重合体は、耐候性や耐熱性に優れ、ブリードアウトや黄変が少ないので、光学材料として有用である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a maleimide compound containing a fluorine atom, a method for producing the same, and a compound containing the compound, in which no polymerization initiator is added or only a very small amount may be added, and the resulting polymer has a low refractive index. The present invention relates to an active energy ray-curable composition having a low refractive index, and a polymer for an optical material having a low refractive index with low odor during bleed-out or curing.
[0002]
[Prior art]
It has long been known that a resin containing a fluorine atom has a low refractive index, and has been widely used as a coating agent or an adhesive for an optical material or as an optical material having an antireflection function.
In recent years, the element structure has been simplified for the purpose of improving the productivity of these optical materials and the like, and not only optical characteristics but also strength and the like have been required as optical materials. In order to satisfy these demands, material development utilizing ultraviolet curing and the like has been actively pursued. For example, an optical thin film obtained by polymerizing a photocurable composition containing a curable compound having a fluorine atom and an acryloyl group by light irradiation is disclosed (for example, see Patent Document 1).
[0003]
Generally, there is a correlation between the fluorine atom content of a compound and the refractive index of the compound, and it is known that the higher the fluorine atom content, the lower the refractive index.
On the other hand, the higher the fluorine atom content of the compound, the lower the compatibility with the organic compound. For example, in the case of the curable compound having a fluorine atom and an acryloyl group described in Patent Literature 1, the photopolymerization initiator usually added to the photocurable composition is an organic compound, so that it is difficult to be compatible with the curable compound, and a uniform composition It was difficult to make things. In addition, many common photopolymerization initiators have a high refractive index, which is disadvantageous for lowering the refractive index of optical materials, yellowing or bleeding out of the resin due to the polymerization initiator, and odor during molding. Was sometimes a problem.
[0004]
Recently, several photocuring systems that do not use these photopolymerization initiators have been proposed. One of these, a photocurable composition containing a maleimide compound (see, for example, Patent Documents 2, 3 and 4) is cured by light irradiation without using a photopolymerization initiator. It is known to Therefore, if a maleimide compound having a low refractive index is designed and applied to an optical material, the above-mentioned problems caused by the addition of the photopolymerization initiator can be solved.
[0005]
N-fluoroalkylmaleimide is known as a maleimide compound containing fluorine with a low refractive index, and an optical fiber clad material excellent in heat resistance using a copolymer containing the compound as one of the components is known. . However, since the copolymer using the monofunctional maleimide is a linear polymer having no cross-linking site, there is a problem that durability and strength are low. Therefore, a polyfunctional maleimide compound that can be used for a crosslinking coating agent having higher durability and strength has been desired.
[0006]
Although several methods for synthesizing a polyfunctional maleimide compound are known, in order to utilize a fluorine-containing alcohol which is easily available as a raw material having a high fluorine content, a method of reacting with a maleimide carboxylic acid derivative (for example, Patent document 2) is advantageous. However, in the method disclosed in the publication, when an alcohol having a fluorine atom bonded to a methylene group farther than the δ-position of the hydroxy group is used, the reaction can be performed, but the methylene group at the β-position of the hydroxy group can be reacted. If an alcohol with a fluorine atom bonded to it is used, the reaction will not proceed at all, and a polyfunctional maleimide compound with a high fluorine atom content and a short distance between cross-linking points, which is useful as a low-refractive coating material, will be designed. Could not be synthesized.
[0007]
[Patent Document 1]
JP-A-11-1633
[Patent Document 2]
JP-A-11-124403
[Patent Document 3]
JP-A-11-124404
[Patent Document 4]
JP 2000-319252 A
[Patent Document 5]
Japanese Patent No. 2871086
[0008]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to provide a fluorine-containing polyfunctional maleimide compound, which contains the compound, does not add a photopolymerization initiator at all, or a very small amount even if added, A curable composition that can be photocured, a polymer for an optical material having a low refractive index obtained by photocuring the curable composition, and a polyfunctional maleimide compound in which fluorine is substituted at a specific position. It is to provide a manufacturing method.
[0009]
[Means for Solving the Problems]
The present inventors have found that a polyfunctional maleimide compound having a specific structure and a large fluorine content solves the above problem.
That is, by having a plurality of maleimide groups, a photopolymerization initiator is not added at all, or even if it is added in a very small amount, a photocuring can be performed well, and a cured product excellent in durability and strength can be obtained.
Among these maleimide compounds, polyfunctional maleimide compounds having a high fluorine atom content and a short distance between cross-linking points, which are useful as low-refractive coating materials that could not be synthesized by conventional methods, are maleimide acetic acid acid halides. When reacting with an alcohol compound having a fluorine atom bonded to the β-position methylene group of the hydroxy group, the reaction can be performed by dropping pyridine or a pyridine derivative into the reaction vessel under a temperature condition at which the reaction occurs. it can.
[0010]
That is, the present invention provides a maleimide compound represented by the general formula (1).
[0011]
Embedded image

(In the formula, X represents an alkylene group or a polymethylene group having 1 to 10 carbon atoms in which some or all of the hydrogen atoms may be substituted with a fluorine atom. A plurality of Xs may be the same or different. Good, Z is Z ₁ Or Z ₂ − (Z ₃ ) _m And Z ₁ Is an n-valent aliphatic hydrocarbon group having 1 to 70 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom (provided that one or more methylene groups having no fluorine atom as a substituent are Oxygen atoms that are not adjacent to each other may be substituted by -O-, -CO-, -OCO-, -CO-O-, -NHCO-O- or -OCONH-), and Z ₂ Represents an isocyanuric ring, a benzene ring, a naphthalene ring, a tetrahydrofuran ring, a decahydronaphthalene ring, a norbornene ring, or a cyclohexane ring having 2 to 8 free valences; ₃ Is a divalent aliphatic hydrocarbon group having 1 to 70 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom (provided that one or more methylene groups having no fluorine atom as a substituent are And oxygen atoms that are not adjacent to each other may be substituted with -O-, -CO-, -OCO-, -CO-O-, -NHCO-O-, or -OCONH-. Z ₂ Represents the same integer as the free valency, and n represents an integer of 2 to 8. )
[0012]
The present invention also provides an active energy ray-curable composition containing the maleimide compound represented by the general formula (1).
[0013]
Further, the present invention provides a polymer for a low-refractive optical material having a refractive index of 1.47 or less, which is obtained by polymerizing the active energy ray-curable composition described above.
[0014]
Further, the present invention, in a reaction vessel, when reacting an acid halide of maleimide acetic acid and an alcohol compound having a fluorine atom bonded to the β-position methylene group of the hydroxy group, under a temperature condition under which the reaction occurs, Provided is a method for producing a maleimide compound containing a fluorine atom, wherein pyridine or a pyridine derivative is dropped into the reaction vessel.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Description of the maleimide compound represented by the general formula (1)
The maleimide compound represented by the general formula (1) is obtained by reacting a maleimide carboxylic acid with a polyol. The following shows an example of the reaction.
[0016]
Embedded image

[0017]
In the formula, (a) represents a maleimide carboxylic acid, (b) represents a polyol, and (c) represents a maleimide compound represented by the general formula (1) of the present invention.
[0018]
In the general formula (1), X represents an alkylene group having 1 to 10 carbon atoms or a polymethylene group in which some or all of the hydrogen atoms may be substituted with fluorine atoms. A plurality of Xs may be the same or different.
Examples of the maleimide carboxylic acid (a) having X as a partial structure include maleimidoacetic acid, maleimidopropionic acid, maleimidobutyric acid, maleimidocaproic acid, and maleimidoundecanoic acid. The longer the chain length of X, the lower the number of maleimide groups per unit mass of the maleimide compound, so that the finally obtained cured product has a lower crosslink density, and the hydrogen atom of the alkylene group or polymethylene group constituting X When the substitution rate of fluorine atoms is low, the content of fluorine atoms as a maleimide compound is also reduced. Therefore, as the maleimide carboxylic acid used in the present invention, maleimide acetic acid having the shortest X is preferable.
These maleimide carboxylic acids are known in the art, such as those disclosed in Journal of Applied Polymer Science, Vol. 57, p. 219 (1995) and Journal of Organic Chemistry, Vol. 62, p. 2652 (1997). It can be synthesized by a method.
[0019]
In the general formula (1), n, that is, the number of maleimide groups is 2 to 8, and 2 to 4 is more preferable. As a coating agent having high strength, it is advantageous to have a large number of functional groups, but generally, a fluorine-containing polyol that is easily available is a diol, and a compound that serves as a nucleus having no fluorine atom when multifunctionalized is used. N is preferably 2 because it is disadvantageous for lowering the refractive index of the compound that must be used.
[0020]
In the general formula (1), Z ₁ Is an n-valent aliphatic hydrocarbon group having 1 to 70 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom (provided that one or more methylene groups having no fluorine atom as a substituent are oxygen Atoms that are not adjacent to each other may be substituted with -O-, -CO-, -OCO-, -CO-O-, -NHCO-O- or -OCONH-), and Z ₃ Is a divalent aliphatic hydrocarbon group having 1 to 70 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom (provided that one or more methylene groups having no fluorine atom as a substituent are oxygen And the atoms that are not adjacent to each other may be substituted with -O-, -CO-, -OCO-, -CO-O-, -NHCO-O-, or -OCONH-.). The aliphatic hydrocarbon group is preferably acyclic, and may partially include a cyclic group. On the other hand, if the number of carbon atoms is 70 or more, the distance between the crosslinking points becomes too long, and the strength of the material decreases, which is not preferable.
Among them, a divalent alkylene group or a polymethylene group having 1 to 40 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom, or a divalent group in which they are connected by -O- (ether bond) is preferable. In these structures, the raw materials are relatively easily available, and the factor for raising the refractive index is minimized. In particular, the divalent group in which the alkylene group or the polymethylene group is connected by an ether bond is more preferable than the alkylene group or the polymethylene group substituted with a fluorine atom in many cases even when the fluorine content is the same and the refractive index can be reduced.
[0021]
Z ₁ Examples of the polyol (b) having n = 2 in the partial structure thereof include 2,2,3,3,4,4-hexafluoro-1,5-pentanediol, 2,2,3,3,4 , 4,5,5-octafluoro-1,6-hexanediol, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-octanediol Perfluoroalkyldiols such as perfluorotriethylene glycol and perfluorotetraethylene glycol; α- (1,1-difluoro-2-hydroxyethyl) -ω- (2,2-difluoroethanol) Poly (oxy-1,1,2,2-tetrafluoroethylene), α- (1,1-difluoro-2-hydroxyethyl) -ω- (2,2-difluoroethanol) (Oxy-difluoromethylene), α- (1,1-difluoro-2-hydroxyethyl) -ω- (2,2-difluoroethanol) poly (oxy-difluoromethylene) (oxy-1,1,2,2- Polyperfluoroalkylene ether diols such as tetrafluoroethylene); 3-perfluorobutyl-1,2-epoxypropane, 3-perfluorooctyl-1,2-epoxypropane, 3-perfluorobutyl-1,2-epoxy Ring-opening diols of fluoroalkyl epoxides such as propane; and 2,2-bis (4-hydroxycyclohexyl) hexafluoropropane. Further, a diol obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to these fluorine-containing diols can also be used.
[0022]
Also, Z ₁ As the polyol (b) having a partial structure of n ≧ 3, 1,1,1-tris (2,2,3,3,4,4,5,5-octafluoro-6-hydroxyhexyloxymethyl) Ethane, 1,1,1-tris (2,2,3,3,4,4,5,5-octafluoro-6-hydroxyhexyloxymethyl) propane, 1,1,1-tris (2,2, 3,3,4,4,5,5,6,6-decafluoro-8-hydroxyoctyloxymethyl) propane, 2,2-bis (2,2,3,3,4,4,5,5- Octafluoro-6-hydroxyhexyloxymethyl) -1,3-bis (2,2,3,3,4,4,5,5-octafluoro-6-hydroxyhexyloxy) propane, 1- (2,2 , 3,3,4,4,5,5-octafluoro-6-hydroxy Hexyloxy) -3- [3- (2,2,3,3,4,4,5,5-octafluoro-6-hydroxyhexyloxy) -2,2-bis (2,2,3,3, 4,4,5,5-octafluoro-6-hydroxyhexyloxymethyl) propoxy] -2,2-bis (2,2,3,3,4,4,5,5-octafluoro-6-hydroxyhexyl It is also possible to use a fluorine-containing polyol such as (oxymethyl) propane or a polyol obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide thereto.
[0023]
Z ₂ − (Z ₃ ) _m As the polyol (b) having a cyclic structure having a partial structure of, for example, hexamethylene diisocyanate trimer, tris (2-carboxyethyl) isocyanurate and the aforementioned Z ₁ Triols having an isocyanuric ring obtained by reacting a fluorine-containing diol as described above, cyclohexane-1,2,4-tricarboxylic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, trimellitic acid, pyromellitic acid, naphthalene -2,3,6,7-tetracarboxylic acid, naphthalene-1,4,5,8-tetracarboxylic acid, decahydronaphthalene-1,4,5,8-tetracarboxylic acid, decahydronaphthalene-1,2 , 3,4,5,6,7,8-octacarboxylic acid, tetrahydrofuran-2,3,4,5-tetracarboxylic acid, 2,3,5,6-norbornenetetraacetic acid and 4,4 '-(hexa Fluoroisopropylidene) diphthalic acid, Z ₁ And a 3-8 functional polyfunctional alcohol having a cyclohexane ring, a naphthalene ring, a decahydronaphthalene ring, a tetrahydrofuran ring, a norbornene ring or a benzene ring, which has been reacted with the above-mentioned fluorine-containing diols. Z ₂ Isocyanuric ring, benzene ring, naphthalene ring, decahydronaphthalene ring, tetrahydrofuran ring, norbornene ring, cyclohexane ring is a branch site for increasing the number of maleimide groups, and this site also contains a fluorine atom However, in many cases, it is difficult to obtain a raw material, and generally, it does not have fluorine, which causes an increase in the refractive index. However, in applications requiring particularly high strength, it is advantageous because the distance between crosslinking points can be reduced.
[0024]
The higher the fluorine content in the maleimide compound of the present invention, the better, preferably 25% or more, more preferably 30% or more. Even with the same fluorine content, Z ₁ Or Z ₃ Is often a group having —O— (ether bond), which can lower the refractive index more than an alkylene group or a polymethylene group substituted with fluorine.
[0025]
Description of maleimide compounds represented by general formulas (2) and (3)
Among the compounds represented by the general formula (1), a compound represented by the following general formula (2) has a particularly low refractive index and is preferable.
[0026]
Embedded image

[0027]
Where X ₁ And X ₂ Each independently represents an alkylene group having 1 to 10 carbon atoms or a polymethylene group in which some or all of the hydrogen atoms may be substituted by fluorine atoms, and r represents an integer of 1 to 20.
[0028]
The compound represented by the general formula (2) has few components that increase the refractive index, and the content of fluorine atoms that lowers the refractive index increases. Therefore, the refractive index of the obtained cured product decreases. As r increases, the viscosity of the active energy ray-curable composition tends to increase.
[0029]
Further, among the compounds represented by the general formula (1), the compound represented by the following general formula (3) has a low viscosity of the active energy ray-curable composition and has a low refractive index. Obtained and preferred.
[0030]
Embedded image

[0031]
Where X ₁ And X ₂ Each independently represents an alkylene group having 1 to 10 carbon atoms or a polymethylene group in which some or all of the hydrogen atoms may be substituted by fluorine atoms, and p and q may be the same or different, and It is an integer of 20 and p + q is 1-20. Here, the integers represented by p and q represent the ratio of the number of units in parentheses, and the sequence of each unit in the alcohol residue may be random.
Preferred embodiments of the compounds represented by formulas (1) to (3) are shown below.
[0032]
Embedded image

[0033]
Embedded image

[0034]
Embedded image

Poly (perfluoroalkylene ether) diol molecular weight: 1000, 1500, 2000
[0035]
Embedded image

Poly (perfluoroalkylene ether) diol molecular weight: 1000, 1500, 2000
[0036]
Embedded image

[0037]
Synthesis method
Among the compounds represented by the general formula (1), as a fluorine atom-containing alcohol, an alkylene oxide having a fluorine atom at a position farther than a methylene group at the δ-position from a hydroxy group, an alkylene oxide having no fluorine atom, and the like When using an alcohol terminal-modified with, known methods, for example, dehydration condensation reaction of maleimide carboxylic acid and alcohol, dehydrohalogenation reaction of acid halide of maleimide carboxylic acid and alcohol, or maleimide carboxylic acid It can be produced by a known ester synthesis reaction such as a transesterification reaction between an ester and an alcohol. In the ester synthesis reaction, an acid catalyst, an aliphatic or aromatic sulfonic acid, an organotin compound, a metal halide, a metal oxide, etc., a commonly used esterification catalyst or a transesterification catalyst, and triethylamine in a dehydrohalogenation reaction A known and commonly used hydrogen halide scavenger such as pyridine, collidine or the like can be used. In order to prevent the maleimide group from thermally polymerizing during the ester synthesis reaction, a known and commonly used polymerization inhibitor such as hydroquinone or 4-tert-butylcatechol may be used.
[0038]
In the compounds and the like represented by the general formulas (2) and (3), as the alcohol containing a fluorine atom, an alcohol compound in which a fluorine atom is bonded to a methylene group at the β-position of a hydroxy group is used. It does not react in a known manner. The present inventors, when reacting an acid halide of maleimide acetic acid and an alcohol compound in which a fluorine atom is bonded to a methylene group at the β-position of a hydroxy group in a reaction vessel, under a temperature condition under which the reaction occurs, It has been found that the reaction proceeds when pyridine or a pyridine derivative is dropped into the reaction vessel.
[0039]
The base that can be used in this reaction is pyridine or a pyridine derivative. In this reaction, a relatively high reaction temperature is required because an alcohol compound having a fluorine atom bonded to the β-methylene group of the hydroxy group having a low reactivity is required. Polymerization occurs. In addition, the reaction proceeds only when pyridine or a pyridine derivative is added dropwise under conditions where the reaction can occur. The reason for this has not been clarified, but it is presumed to be due to the relatively strong acidity of the alcohol compound in which a fluorine atom is bonded to the β-position methylene group of the hydroxy group.
Examples of the pyridine derivative used in this reaction include pyridine having an alkyl group such as picoline, ethylpyridine, lutidine and collidine, pyridine having a halogen such as chloropyridine and dichloropyridine, nitrogen-containing heteroaromatic compounds such as quinoline and isoquinoline. Is raised.
[0040]
The amount of pyridine or the pyridine derivative used in this reaction may be at least equivalent to the amount of hydrogen halide generated by the reaction. About 2 equivalents are preferred.
Addition of pyridine or a pyridine derivative by dropping in this reaction is carried out under a temperature condition at which a reaction between an alcohol compound in which a fluorine atom is bonded to the methylene group at the β-position of the hydroxy group and an acid halide of maleimide acetic acid can occur, and It is preferable to add dropwise according to the progress of the reaction. The preferred temperature range at which this reaction can occur depends on the structure of the alcohol compound having a fluorine atom bonded to the methylene group at the β-position of the hydroxy group, the structure of the acid halide of maleimide acetic acid, the solvent used in the reaction, and the like. Although it is generally difficult to show, it is in the range of about 60 to 150 ° C. Further, the appropriate dropping rate also varies depending on the structure of the substrate, the solvent, and the reaction temperature which affect the reaction rate. Therefore, it is difficult to specify a suitable range, but the range is from 30 minutes to several hours.
As the reaction solvent used in the present reaction, any solvent can be used as long as it does not affect the present reaction. Although it depends on the structure of the alcohol compound used, it is preferable to use a solvent that can uniformly dissolve the alcohol compound at a temperature at which the reaction occurs. Examples of such a solvent include toluene, methyl ethyl ketone, ethyl acetate, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like.
In addition, also in the present reaction, an alcohol having a fluorine atom at a position farther than the δ-position methylene group of the hydroxy group or a terminal-modified alcohol with an alkylene oxide having no fluorine atom is used as the above-mentioned alcohol containing a fluorine atom. As in the case of the reaction, a polymerization inhibitor can be used.
[0041]
Active energy ray-curable composition
The maleimide compound of the present invention is used alone or with the addition of a copolymerizable polymerizable compound as an active energy ray-curable composition. Such polymerizable compounds include, for example, (meth) acrylic acid, (meth) acrylates, styrene, and other known monomers copolymerizable with a maleimide compound, and urethane (meth) acrylates and the like. An oligomer having a polymerizable functional group is exemplified.
Further, using the maleimide compound of the present invention as an initiator, it is also possible to cure a low refractive material such as a (meth) acrylate having a fluorine atom.
[0042]
Since the maleimide compound of the present invention itself acts as a polymerization initiator, it is not necessary to add a polymerization initiator to the active energy ray-curable composition of the present invention. When the content of the maleimide compound of the present invention is extremely low, or when a high polymerization rate is required, as in the case of ordinary thermal polymerization or active energy ray polymerization, a known and commonly used thermal polymerization initiator or A photopolymerization initiator may be used. However, when the obtained polymer is used for an optical material or the like, it is preferably used in the range of 0 to 1% based on the total amount of the polymerizable compound contained in the active energy ray-curable composition. If the addition ratio exceeds 1% by mass, the unreacted polymerization initiator remaining in the polymer and its decomposition products may cause odor at the time of curing and decrease the light resistance of the cured product. Cheap.
[0043]
To the active energy ray-curable composition of the present invention, a known and commonly used polymerization inhibitor such as hydroquinone or 4-tert-butylcatechol, or a solvent such as acetone, toluene, ethyl acetate, chloroform, or dichloromethane can also be added. .
[0044]
The active energy ray-curable composition of the present invention can be cured by irradiation with active energy rays such as ultraviolet rays and electron beams. Among them, ultraviolet rays are preferred. Ultraviolet light sources include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, chemical lamps, black light lamps, mercury-xenon lamps, excimer lamps, show arc lamps, helium / cadmium lasers, argon lasers, and excimer lamps. A laser or the like can be used.
[0045]
Further, the active energy ray-curable composition of the present invention can be cured by heat. The heat source at this time is not particularly limited, and a known heat source can be used. Also in this case, curing can be carried out without a polymerization initiator, but if necessary, the above-mentioned known and commonly used thermal polymerization initiator may be added.
[0046]
When the active energy ray-curable composition of the present invention is used as a low-refractive-index optical material such as an optical component or a coating agent, an adhesive, or an antireflection agent, the refractive index of the finally obtained polymer is used. Is preferably 1.47 or less. In order to obtain a polymer having such a low refractive index, a (meth) acrylic resin having a copolymerizability with the maleimide compound of the present invention and having a fluorine atom in the molecule is required for the active energy ray-curable composition. It is advisable to add a system monomer. Examples of the (meth) acrylic monomer having a fluorine atom include 2,2,3,3,3-pentafluoroethyl acrylate, 2- (perfluorooctyl) ethyl acrylate, 2,2,3,3,3 Monofunctional monomers such as -pentafluoroethyl methacrylate and 2- (perfluorooctyl) ethyl methacrylate, 2,2,3,3,4,4-hexafluoro-1,5-pentanediol, 2,2,3 , 3,4,4,5,5-octafluoro-1,6-hexanediol, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1, Perfluoroalkyl diols such as 8-octanediol; perfluoroalkylene glycols such as perfluorotriethylene glycol and perfluorotetraethylene glycol; α (1,1-difluoro-2-hydroxyethyl) -ω- (2,2-difluoroethanol) poly (oxy-1,1,2,2-tetrafluoroethylene), α- (1,1-difluoro-2) -Hydroxyethyl) -ω- (2,2-difluoroethanol) poly (oxy-difluoromethylene), α- (1,1-difluoro-2-hydroxyethyl) -ω- (2,2-difluoroethanol) poly ( Examples thereof include diacrylates and dimethacrylates of diols such as polyperfluoroalkylene ether diols such as (oxy-difluoromethylene) (oxy-1,1,2,2-tetrafluoroethylene).
[0047]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. Unless otherwise specified, “parts” and “%” represent “parts by mass” and “% by mass”, respectively.
[0048]
(Synthesis Example 1) Synthesis of maleimide acetic acid
In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, a Dean-Stark fractionator and a condenser, 1400 parts of toluene, 52 parts of p-toluenesulfonic acid monohydrate and 28 parts of triethylamine were sequentially charged and stirred. After adding 300 parts of maleic anhydride, it was dissolved while heating to 30 ° C. After further adding 230 parts of glycine, the mixture was reacted at 70 ° C. for 3 hours with stirring. Thereafter, 500 parts of toluene and 600 parts of triethylamine were further added, and the mixture was reacted for 1 hour while heating and refluxing the solvent to remove generated water. The residue obtained by evaporating the solvent from the reaction mixture was added with 4 mol / dm ³ After adjusting the pH to 2 by adding hydrochloric acid, the mixture was heated and recrystallized to obtain 73 parts of a pale yellow solid of maleimide acetic acid.
[0049]
(Synthesis Example 2) Synthesis of maleimide acetic acid chloride
20 parts of maleimide acetic acid and 200 parts of toluene were charged into a reaction vessel equipped with a dropping funnel, a stirrer, a thermometer, a nitrogen inlet tube and a sodium hydroxide aqueous solution trap, and 50 parts of thionyl chloride was added dropwise with stirring at room temperature. After completion of the dropwise addition, the reaction mixture was heated to 50 ° C. and reacted for 5 hours with stirring. After cooling, the reaction mixture was distilled under reduced pressure to obtain 20 parts of maleimide acetic acid chloride.
[0050]
(Synthesis Example 3) Synthesis of acid chloride of tris (2-carboxyethyl) isocyanurate
A reaction vessel equipped with a cooling device, a dropping funnel, a stirrer, and a thermometer was charged with 120 parts of 1,3,5-tris (2-carboxyethyl) isocyanurate manufactured by Shikoku Chemicals and 450 parts of dimethylformamide, and cooled to 20 ° C. After stopping the cooling device, 146 parts of thionyl chloride was added from the dropping funnel over 2 hours. After stirring for 2 hours after the completion of the dropwise addition, the stirring was stopped and the reactor was cooled again. The mixture was cooled to 15 ° C., and the generated solid was separated by suction filtration. The solid was washed with 50 parts of chloroform and then dried under reduced pressure to obtain 120 parts of 1,3,5-tris (2-carboxyethyl) isocyanurate acid chloride (white solid).
[0051]
(Example 1)
175 parts of maleimide acetate chloride, 100 parts of 2,2,3,3,4,4,5,5-octafluorohexane-1,6-diol “A-7412” manufactured by Daikin Chemicals Co., Ltd., p-methoxyphenol 1 Then, 0.4 parts and 2500 parts of toluene were charged into a reaction vessel, and the temperature was raised to 100 ° C. with stirring, and then the temperature was maintained for 2 hours. Next, 58 parts of pyridine was added dropwise over 30 minutes, and the same temperature was maintained for another 2 hours. Toluene was distilled off from the reaction mixture, the residue was dissolved in a mixed solvent of ethyl acetate / toluene, recrystallized, and then desolvated to remove 2,2,3,3,4,4,5,5-octafluoro. 20 parts of bismaleimide acetic acid ester of hexane-1,6-diol [maleimide compound (1-1)] was obtained.
¹ H nmr (CD ₃ COCD ₃ ) Δ 7.00 (single line, 4H), δ 4.40 (single line, 4H), δ 4.75 (multiple line, 4H)
[0052]
Using the obtained maleimide compound (1-1), an active energy ray-curable composition having the following composition was prepared.
80 parts of maleimide compound (1-1)
20 parts of methyl methacrylate (hereinafter abbreviated as "MMA")
N, N-dimethylformamide 900 parts
[0053]
(Example 2)
94 parts of maleimide acetic acid chloride, 100 parts of a fluorine-containing diol “FLUORLINK D10” manufactured by Ausimont, represented by the following general formula (4), 1.0 part of p-methoxyphenol, and 2,500 parts of toluene are charged into a reaction vessel and stirred. The temperature was raised to 100 ° C. and kept at the same temperature for 2 hours.
[0054]
Embedded image

(P and q are integers and are indeterminate and are mixtures of various values; number average molecular weight 1000 measured by NMR)
[0055]
Next, 31 parts of pyridine was added dropwise over 30 minutes, and the same temperature was maintained for another 2 hours. The toluene was distilled off from the reaction mixture, the residue was dissolved in ethyl acetate, recrystallized, and then the solvent was removed. The bismaleimide acetate [maleimide] of a fluorine-containing diol represented by the following general formula (4) was removed. Compound (1-2)] was obtained.
¹ H nmr (CD ₃ COCD ₃ ) 6.85 (single line, 4H), δ 4.40 (single line, 4H), δ 4.68 (multiple line, 4H)
[0056]
An active energy ray-curable composition was prepared in the same manner as in Example 1 except that the maleimide compound (1-2) was used instead of the maleimide compound (1-1) in Example 1.
[0057]
(Example 3)
300 parts of a fluorine-containing diol “FLUOROLINK E10” manufactured by Ausimont and represented by the following general formula (5), 14 parts of triethylamine, and 3000 parts of toluene are added to the reaction vessel, and the tris obtained in Synthesis Example 3 is stirred at room temperature with stirring. A solution consisting of 16 parts of (2-carboxyethyl) isocyanurate acid chloride and 50 parts of toluene was added dropwise.
[0058]
Embedded image

(U and v are integers and average of 1 to 2; s and t are integers and are indeterminate and have various values. A mixture of various values. Number average molecular weight measured by NMR is 1000)
[0059]
After completion of the dropwise addition, the reaction mixture was heated to 50 ° C. and reacted for 5 hours. After cooling, the mixture was diluted with ethyl acetate and filtered to remove triethylamine hydrochloride. Ethyl acetate was distilled off under reduced pressure, and the obtained mixture was separated by column chromatography, and 40 parts of 3 mol FLUOROLLINK E10 ester (intermediate compound A) of tris (2-carboxyethyl) isocyanurate as a target compound was obtained. Obtained.
33 parts of the obtained intermediate compound A, 100 parts of toluene, 0.3 part of p-methoxyphenol and 5 parts of pyridine are added to a reaction vessel, and while stirring, 26 parts of maleimide acetic acid chloride and 20 parts of toluene are added at room temperature. Solution was added dropwise. After completion of the dropwise addition, the reaction mixture was heated to 90 ° C. and reacted for 10 hours. Toluene was distilled off from the reaction mixture, and the residue was purified by column chromatography to obtain 5 parts of [maleimide compound (1-3)] in which three hydroxy groups of intermediate compound A were esterified with maleimide acetic acid. .
¹ H nmr (CD ₃ COCD ₃ ) 6.95 (single line, 6H), δ 4.40 (single line, 6H), δ 4.60 (multiple line, 14H), δ 3.90 (multiple line, 14H), δ 3.60 (multiple line, 18H) , Δ2.55 (triple line, 6H)
[0060]
Using the obtained maleimide compound (1-3), an active energy ray-curable composition having the following composition was prepared.
Maleimide compound (1-3) 60 parts
Compound (ratio-1) 40 parts
N, N-dimethylformamide 900 parts
[0061]
(Comparative Example 1)
100 parts of 2,2,3,3,4,4,5,5-octafluorohexane-1,6-diol “A-7412” manufactured by Daikin Chemicals Co., Ltd., 67 parts of pyridine and 1.0 parts of p-methoxyphenol The mixture was charged into a reaction vessel, and 92 parts of acrylic acid chloride was added dropwise at room temperature with stirring. After the completion of the dropwise addition, the temperature of the reaction mixture was raised to 100 ° C., and maintained at the same temperature for 5 hours. The reaction mixture was purified by column chromatography to give 14 parts of 2,2,3,3,4,4,5,5-octafluorohexane-1,6-diol diacrylate [compound (ratio-1)]. Obtained.
[0062]
Using the obtained compound (ratio -1), an active energy ray-curable composition having the following composition
A composition was prepared.
80 parts of compound (ratio-1)
MMA 20 copies
N, N-dimethylformamide 900 parts
[0063]
(Comparative Example 2)
Using the obtained compound (ratio -1), an active energy ray-curable composition having the following composition
A composition was prepared.

[0064]
(Comparative Example 3)
155 parts of maleimide acetic acid, 2,2,3,3,4,4,5,5-octafluorohexane manufactured by Daikin Chemicals Co., Ltd. were placed in a reaction vessel equipped with a stirrer, a thermometer, a Dean-Stark fractionator, and a condenser. 100 parts of -1,6-diol "A-7412", 1.4 parts of p-methoxyphenol, 7.2 parts of p-toluenesulfonic acid and 2500 parts of toluene are charged, heated with stirring and generated by the reaction. The mixture was refluxed for 16 hours to remove water, but no esterification reaction occurred.
[0065]
(Comparative Example 4)
211 parts of butyl maleimide acetate, 100 parts of 2,2,3,3,4,4,5,5-octafluorohexane-1,6-diol “A-7412” manufactured by Daikin Chemicals Co., Ltd., p-methoxyphenol 1 A reaction vessel was charged with .4 parts, 6.2 parts of dibutyltin oxide and 2500 parts of toluene, and heated and refluxed with stirring. In order to remove butanol produced by the reaction, 60 parts of toluene was distilled off per hour, and the reaction was continued for 20 hours while adding 60 parts of fresh toluene, but no transesterification reaction occurred.
[0066]
(Comparative Example 5)
100 parts of 2,2,3,3,4,4,5,5-octafluorohexane-1,6-diol “A-7412” manufactured by Daikin Chemicals Co., Ltd., 67 parts of pyridine and 1.0 parts of p-methoxyphenol Then, 175 parts of maleimide acetic acid chloride was added dropwise at room temperature with stirring. After completion of the dropwise addition, the temperature of the reaction mixture was raised to 100 ° C. and maintained at the same temperature for 5 hours, but the desired ester was not obtained.
[0067]
(Curability test of active energy ray curable composition coating film)
The active energy ray-curable compositions prepared in Examples and Comparative Examples were applied to a glass plate with a bar coater so that the coating thickness after curing was 10 μm, and using a UV irradiation device manufactured by Eye Graphics Co., Ltd. Irradiation dose is 3kJ / m ² UV light was applied to obtain Thereafter, N, N-dimethylformamide was volatilized in a drier at 50 ° C. and normal pressure, and subsequently at 50 ° C. under a reduced pressure of 133 Pa. The obtained cured coating film was checked for odor by a sensory test and the degree of curing was checked by a finger touch test. A case where a practical curing degree was obtained was evaluated as ○, and a case where a practical curing degree was not obtained was evaluated as x.
[0068]
(Refractive index measurement)
After applying the active energy ray-curable compositions prepared in Examples and Comparative Examples on a glass plate having a thickness of 6 mm, using a bar coater so that the coating thickness after curing becomes 0.05 to 1.0 μm, Irradiation dose of 3 kJ / m using UV irradiator manufactured by Eye Graphics ² UV light was applied to obtain Thereafter, N, N-dimethylformamide was volatilized in a drier at 50 ° C. and normal pressure, and subsequently at 50 ° C. under a reduced pressure of 133 Pa. Without peeling the obtained cured coating film from the glass plate, the refractive index of the cured coating film with respect to 632.8 nm light was measured using an ellipsometer “MARY-102MM” manufactured by Photo Device.
[0069]
(Weather resistance test)
The cured coating film of the active energy ray-curable composition obtained in the above (curing test of the active energy ray-curable composition coating film) was subjected to nitrogen measurement using a metal weather weathering tester manufactured by Daipla Wintes Co., Ltd. Under atmosphere, light irradiation amount 180 J / cm ² 11 hours of repetition of standing for 4 hours at hr and then for 4 hours without light irradiation, and the presence or absence of bleed-out was examined by visual inspection. The case where no bleed-out was observed was evaluated as ○, and the case where bleed-out was observed was evaluated as x.
[0070]
[Table 1]
(Table 1)

Photopolymerization initiator: Irgacure 184 manufactured by Ciba Specialty Chemicals
[0071]
As a result, in Examples 1 and 2, coating films having no odor and excellent weather resistance and having a refractive index of 1.47 or less were obtained. Example 3 is an example in which an acrylic monomer having a fluorine atom was added to the maleimide compound of the present invention. However, the composition was cured without a photopolymerization initiator, and there was no problem in coating film properties. The example using the acrylic monomer having a fluorine atom did not cure unless a photopolymerization initiator was used (Comparative Example 1), and the odor and weather resistance were poor when the photopolymerization initiator was used (Comparative Example 2).
[0072]
【The invention's effect】
The maleimide compound of the present invention does not add a photopolymerization initiator at all, or it is added in a very small amount even if it is added, so that a photocuring can be performed well and a cured product having excellent durability and strength can be obtained.
Among these maleimide compounds, polyfunctional maleimide compounds having a high fluorine atom content and a short distance between cross-linking points, which are useful as low-refractive coating materials that could not be synthesized by conventional methods, are maleimide acetic acid acid halides. When reacting with an alcohol compound having a fluorine atom bonded to the β-position methylene group of the hydroxy group, the reaction can be performed by dropping pyridine or a pyridine derivative into the reaction vessel under a temperature condition at which the reaction occurs. it can.
[0073]
Further, a polymer having a refractive index of 1.47 or less obtained by photocuring the active energy ray-curable composition containing the maleimide compound of the present invention is excellent in weather resistance and heat resistance, and has little bleed-out or yellowing. Therefore, it is useful as an optical material.

Claims (7)

A maleimide compound represented by the general formula (1).

(In the formula, X represents an alkylene group or a polymethylene group having 1 to 10 carbon atoms in which some or all of the hydrogen atoms may be substituted with a fluorine atom. A plurality of Xs may be the same or different. Z represents Z ₁ or Z _2- (Z ₃ ) _m , wherein Z ₁ is an n-valent aliphatic hydrocarbon group having 1 to 70 carbon atoms in which one or more hydrogen atoms are substituted by fluorine atoms. (However, one or more methylene groups having no fluorine atom as a substituent may be those in which oxygen atoms are not adjacent to each other, such as -O-, -CO-, -OCO-, -CO-O-, -NHCO —O— or —OCONH—), and Z ₂ represents an isocyanuric ring, a benzene ring, a naphthalene ring, a tetrahydrofuran ring, a decahydronaphthalene ring having 2 to 8 free valences, Norbornene ring Represents cyclohexane ring, Z ₃ represents a divalent aliphatic hydrocarbon group having more than one 1 to 70 carbon hydrogen atom is substituted with a fluorine atom (provided that no fluorine atom as a substituent 1 One or more methylene groups may be substituted with -O-, -CO-, -OCO-, -CO-O-, -NHCO-O-, or -OCONH-, assuming that the oxygen atoms are not adjacent to each other. ), M represents the same integer as the free valence of Z ₂ , and n represents an integer of 2 to 8.) The maleimide compound according to claim 1, wherein the maleimide compound represented by the general formula (1) is a compound represented by the general formula (2).

(Wherein, X ₁ and X ₂ each independently represent an alkylene group having 1 to 10 carbon atoms or a polymethylene group in which some or all of the hydrogen atoms may be substituted with fluorine atoms, and r represents 1 to Represents an integer of 20) The maleimide compound according to claim 1, wherein the maleimide compound represented by the general formula (1) is a compound represented by the general formula (3).

(Wherein, X ₁ and X ₂ each independently represent an alkylene group having 1 to 10 carbon atoms or a polymethylene group in which some or all of the hydrogen atoms may be substituted with fluorine atoms, and p and q represent It is an integer of 0 to 20, which may be the same or different, and p + q is 1 to 20. Here, the integers represented by p and q represent the ratio of the number of units in parentheses. The sequence of each unit in the alcohol residue may be random.) An active energy ray-curable composition comprising the maleimide compound according to claim 1. The active energy ray-curable composition according to claim 4, wherein the content of the polymerization initiator is 0 to 1% by mass based on the polymerizable compound. A polymer for a low-refractive optical material, obtained by polymerizing the active energy ray-curable composition according to claim 4 and having a refractive index of 1.47 or less. When reacting an acid halide of maleimide acetic acid with a compound in which a fluorine atom is bonded to the methylene group at the β-position of the hydroxy group in a reaction vessel, pyridine or A method for producing a maleimide compound containing a fluorine atom, wherein a pyridine derivative is added dropwise.