JP4438124B2 - Dioxazine compound and dye-based polarizing film containing the same - Google Patents

Description

【０００９】
〔式中、Ｒは下式（R1）又は（R2）
【００１０】
−[Ａ]−Ｘ−[Ｃ] （R1）
−[Ａ]−Ｘ−[Ｂ]−Ｙ−[Ｃ] （R2）
【００１１】
の基を表し、ここに［Ａ］は、メチル及びメトキシから選ばれる１若しくは２個の置換基で置換されていてもよいフェニレンを表すか、又はスルホ及び水酸基を有するナフチレンを表し、［Ｂ］は、メチル及びメトキシから選ばれる１若しくは２個の置換基で置換されていてもよいフェニレンを表し、［Ｃ］は、スルホ及びカルボキシルから選ばれる１若しくは２個の水溶性基を有し、さらにメチル、メトキシ及び水酸基から選ばれる置換基で置換されていてもよいフェニルを表すか、又は１若しくは２個のスルホを有し、さらに水酸基で置換されていてもよいナフチルを表し、Ｘ及びＹはそれぞれ独立に、−Ｎ＝Ｎ−又は−ＣＯＮＨ−を表す〕
で示されるジオキサジン化合物を提供し、さらには、当該ジオキサジン化合物を偏光膜基材中に含有してなる染料系偏光膜を提供するものである。
【００１２】
【発明の実施の形態】
式（Ｉ）において、Ｒは前記式（R1）又は（R2）で示される基であり、これらの式中の［Ａ］はフェニレンであるか、又はスルホ及び水酸基を有するナフチレンであり、［Ｂ］はフェニレンであり、［Ｃ］はスルホ及びカルボキシルから選ばれる１個若しくは２個の水溶性基を有するフェニルであるか、又は１個若しくは２個のスルホを有するナフチレンである。［Ａ］及び［Ｂ］で表されるフェニレンは、無置換であっても、メチル及びメトキシから選ばれる１個又は２個の基で置換されていてもよい。［Ｃ］で表されるフェニルは、上記のようにスルホ及び／又はカルボキシルを有するほか、さらにメチル、メトキシ及び水酸基から選ばれる基で置換されていてもよい。また、［Ｃ］で表されるナフチルは、上記のようにスルホを有するほか、さらに水酸基で置換されていてもよい。
【００１３】
［Ａ］及び［Ｂ］で表されるフェニレンは、二色性の面から、無置換の又は、上記した基で置換された１，４−フェニレン、すなわちｐ−フェニレンであるのが有利である。かかるフェニレンとして具体的には、［Ａ］で表されるフェニレンの１−位が式（Ｉ）中のＮＨに結合し、［Ｂ］で表されるフェニレンの１−位が式（R2）中のＸに結合するとして、１，４−フェニレン、２−メチル−１，４−フェニレン、２−メトキシ−１，４−フェニレン、３−メチル−１，４−フェニレン、３−メトキシ−１，４−フェニレン、２，５−ジメトキシ−１，４−フェニレン、２−メチル−５−メトキシ−１，４−フェニレンなどが挙げられる。
【００１４】
また［Ａ］で表されるナフチレンとして具体的には、その２−位が式（Ｉ）中のＮＨに結合するとして、５−ヒドロキシ−７−スルホ−２，６−ナフチレン、８−ヒドロキシ−６−スルホ−２，７−ナフチレンなどが挙げられる。［Ａ］がスルホ及び水酸基を有するナフチレンである場合、これらのスルホ及び水酸基は通常１個ずつでよく、またこの場合は、ナフチレンが結合するＸは−Ｎ＝Ｎ−であるのが普通である。
【００１５】
［Ｃ］で表されるフェニルとしては、例えば、２−、３−又は４−スルホフェニル、２−、３−又は４−カルボキシフェニル、２，４−又は２，５−ジスルホフェニル、２−カルボキシ−４−又は−５−スルホフェニル、２−スルホ−４−又は−５−メチルフェニル、３−スルホ−４−メチルフェニル、２−メチル−５−スルホフェニル、２−スルホ−４−又は−５−メトキシフェニル、３−スルホ−４−メトキシフェニル、２−メトキシ−５−スルホフェニル、２−ヒドロキシ−５−スルホフェニル、３−ヒドロキシ−４−カルボキシフェニルなどが挙げられる。このように［Ｃ］で表されるフェニルは、スルホ及びカルボキシルから選ばれる水溶性基を合計１個又は２個有するものであるが、特に水溶性基としてスルホを１個だけ有するものが適当である。［Ｃ］で表されるフェニルがスルホ及び／又はカルボキシルの他に置換基を有する場合でも、通常は、メチル、メトキシ及び水酸基のうち１個の置換基を有していればよい。
【００１６】
また［Ｃ］で表されるナフチルとしては、例えば、５−、６−、７−又は８−スルホ−２−ナフチル、４−、５−、６−又は７−スルホ−１−ナフチル、６，８−、４，８−又は３，６−ジスルホ−２−ナフチル、３，６−又は４，６−ジスルホ−１−ナフチル、５−ヒドロキシ−７−スルホ−２−ナフチル、６−スルホ−８−ヒドロキシ−２−ナフチル、５−ヒドロキシ−７−スルホ−１−ナフチルなどが挙げられる。［Ｃ］で表されるナフチルが１又は２個のスルホの他に水酸基を有する場合でも、通常は水酸基を１個有していればよい。
【００１７】
式（Ｉ）中のＲで表される基として好ましいものには、次の各式で示されるものが包含される。
【００１８】

【００１９】
式中、Ｘ及びＹは先に定義したとおりであり、ｍは１又は２を表す。
【００２０】
式（Ｉ）で示されるジオキサジン化合物は、例えば、以下に述べる方法によって製造することができる。すなわち、まず下式（II）
【００２１】
Ｒ−ＮＨ₂ （II）
【００２２】
（式中、Ｒは前記の意味を表す）
で示される芳香族アミン化合物を常法によりクロロ炭酸フェニルと反応させて、下式 (III)
【００２３】

【００２４】
（式中、Ｒは前記の意味を表す）
で示されるカルバメート化合物を得る。次いで、このカルバメート化合物と、遊離酸の形で表したときに下式（IV）
【００２５】

【００２６】
で示されるジオキサジン中間化合物とを、水性溶媒中、２０〜６０℃で反応させることにより、式（Ｉ）で示されるジオキサジン化合物を得ることができる。
【００２７】
このようにして得られる式（Ｉ）で示されるジオキサジン化合物は、遊離酸の形でも、塩の形でも存在することができる。塩としては、リチウム塩やナトリウム塩、カリウム塩のようなアルカリ金属塩、アンモニウム塩、エタノールアミン塩やアルキルアミン塩のような有機アミン塩などが挙げられる。この化合物を偏光膜基材に含有させる場合は通常、ナトリウム塩の形で用いるのが好ましい。
【００２８】
また、式（Ｉ）で示されるジオキサジン化合物を偏光膜基材に含有させて偏光膜とする場合は、他の有機染料と併用することにより、色相を補正し、偏光性能を向上させることができる。この場合に用いられる有機染料としては、二色性の高いものであればいかなる染料でもよく、例えば、カラーインデックスに記載される次のようなものが例示される。
【００２９】
シー・アイ・ダイレクト・イエロー 12、28 及び 44、
シー・アイ・ダイレクト・オレンジ 26、39 及び 107、
シー・アイ・ダイレクト・レッド 2、31、79、81 及び 247 など。
【００３０】
本発明の染料系偏光膜は、式（Ｉ）で示される化合物からなる、あるいはさらに他の有機染料を含んでなる二色性染料を、偏光膜基材である高分子フィルムに公知の方法で含有させることによって、製造することができる。この高分子フィルムとしては、例えば、ポリビニルアルコール系の樹脂、ナイロン樹脂、ポリエステル樹脂などからなるものが利用される。 ここでいうポリビニルアルコール系の樹脂には、ポリ酢酸ビニルの部分又は完全ケン化物であるポリビニルアルコール自体のほか、ケン化前のポリ酢酸ビニル、エチレン／酢酸ビニル（ＥＶＡ）樹脂やケン化ＥＶＡ樹脂のような、酢酸ビニルと他の共重合可能な単量体、例えば、エチレンやプロピレンのようなオレフィン類、クロトン酸やアクリル酸、メタクリル酸、マレイン酸のような不飽和カルボン酸類、不飽和スルホン酸類、ビニルエーテル類などとの共重合体及びそのケン化物、さらにはポリビニルアルコールをアルデヒドで変性したポリビニルホルマールやポリビニルアセタールなども包含される。偏光膜基材としては、ポリビニルアルコール系のフィルム、特にポリビニルアルコールフィルムが、染料の吸着性及び配向性の点から、好適に用いられる。
【００３１】
このような高分子フィルムに二色性染料を含有させるにあたっては、通常、高分子フィルムを染色する方法が採用される。染色は、例えば次のようにして行うことができる。まず、二色性染料を水に溶解して染浴を調製する。染浴中の染料濃度は特に制限されないが、通常は０.０００１〜１０重量％の範囲から選択される。また、必要により染色助剤を用いてもよく、例えば、芒硝を染浴中で１〜１０重量％用いるのが好適である。このようにして調製した染浴に高分子フィルムを浸漬し、染色を行う。染色温度は、好ましくは４０〜８０℃である。二色性染料の配向は、高分子フィルムを延伸することによって行われる。延伸する方法としては、例えば湿式法や乾式法など、公知のいずれの方法を採用してもよい。高分子フィルムの延伸は、染色の前に行っても、染色の後に行ってもよい。
【００３２】
二色性染料を含有させ、配向させた高分子フィルムは、必要に応じて、公知の方法によりホウ酸処理などの後処理が施される。このような後処理は、偏光膜の光線透過率、偏光度及び耐久性を向上させる目的で行われる。ホウ酸処理の条件は、用いる高分子フィルムの種類や用いる染料の種類によって異なるが、一般的には、ホウ酸水溶液のホウ酸濃度を１〜１５重量％、好ましくは５〜１０重量％の範囲とし、処理は３０〜８０℃、好ましくは５０〜８０℃の温度範囲で行われる。さらには必要に応じて、カチオン系高分子化合物を含む水溶液でフィックス処理を併せて行ってもよい。
【００３３】
このようにして得られる染料系偏光膜は、その片面又は両面に、光学的透明性及び機械的強度に優れる保護膜を貼合して、偏光板とすることができる。保護膜を形成する材料は、従来から使用されているものでよく、例えば、セルロースアセテート系フィルムやアクリル系フィルムのほか、四フッ化エチレン／六フッ化プロピレン共重合体のようなフッ素樹脂系フィルム、ポリエステル系フィルム、ポリオレフィン系フィルム、ポリアミド系フィルムなどが用いられる。
【００３４】
【実施例】
以下、実施例により本発明をさらに詳細に説明するが、これらは例示的なものであって、本発明をなんら限定するものではない。例中にある％及び部は、特にことわらないかぎり重量基準である。
【００３５】
実施例１
Ｎ−（ｐ−アミノベンゾイル）スルファニル酸ナトリウム８部を水５００部に溶解した後、２０〜２５℃の温度で、１５％炭酸ナトリウム水溶液によりｐＨ７〜８に調整しながら、クロロ炭酸フェニル８部を３０分かけて滴下した。同温度及び同ｐＨで１時間攪拌した後、析出した結晶を濾過して、下式（１）で示される中間体を得た。
【００３６】

【００３７】
得られた中間体の全量と下式（２）
【００３８】

【００３９】
で示されるジオキサジン中間化合物３部を水３００部に加え、１５〜２０℃の温度で、１０％苛性ソーダ水溶液によりｐＨ１１〜１２に調整しながら５時間攪拌した。析出した結晶を濾過し、得られたケーキを６０℃の温水４００部に加えて溶解させた。不溶解物を濾過により除いた後、濾液にエタノール１００部を加えて再度結晶を析出させた。この析出した結晶を濾過することにより、下式（Ia）で示されるジオキサジン化合物を得、この化合物は、水性媒体中でλmax ６２８nmを示した。
【００４０】

【００４１】
実施例２
実施例１で用いたＮ−（ｐ−アミノベンゾイル）スルファニル酸ナトリウムの代わりに、４−アミノアゾベンゼン−４′−スルホン酸ナトリウムを用いて、実施例１と同様の操作を施すことにより、下式（Ib）で示されるジオキサジン化合物を得、この化合物は、水性媒体中でλmax ６２８nmを示した。
【００４２】

【００４３】
実施例３
４−アミノ−４′−〔Ｎ−（ｐ−スルホフェニル）カルバモイル〕アゾベンゼンナトリウム塩１０部をＮ−メチルピロリドン３００部と水１００部の混合液に仕込んだ後、２０〜２５℃の温度で、１５％炭酸ナトリウム水溶液によりｐＨ７〜８に調整しながら、クロロ炭酸フェニル１２部を３０分かけて滴下した。同温度及び同ｐＨで３時間攪拌した後、析出した結晶を濾過して、下式（３）で示される中間体を得た。
【００４４】

【００４５】
得られた中間体の全量と実施例１に示した式（２）のジオキサジン中間化合物３部を水３００部に加え、１５〜２０℃の温度で、１０％苛性ソーダ水溶液によりｐＨ１１〜１２に調整しながら５時間攪拌した。エタノールを５００部加えて析出させた結晶を濾過し、得られたケーキを８０℃の温水６００部に加えて溶解させた。不溶解物を濾過により除いた後、濾液にエタノール２００部を加えて再度結晶を析出させた。この析出した結晶を濾過することにより、下式（Ic）で示されるジオキサジン化合物を得、この化合物は、水性媒体中でλmax ６４７nmを示した。
【００４６】

【００４７】
実施例４
原料化合物を変更して実施例１〜３に準じた操作を施すことにより、それぞれ下式（Id）、（Ie）及び（If）で示されるジオキサジン化合物を得た。
【００４８】

【００４９】
実施例５
厚さ７５μm のポリビニルアルコールフィルム（クラレビニロン＃７５００、（株）クラレ製品）を縦一軸に５倍延伸して、偏光膜基材とした。このポリビニルアルコールフィルムを緊張状態に保ったまま、実施例３で得られた式（Ic）で示されるジオキサジン化合物を０.０２５％、染色助剤である芒硝を２.０％の濃度とした６５℃の水溶液に浸漬した。次に６５℃の７.５％ホウ酸水溶液に５分間浸漬したのち、取り出して２０℃の水で２０秒間洗浄し、５０℃で乾燥することにより、偏光膜を得た。得られた偏光膜のλmax は６４０nmであり、この偏光膜は高い偏光度を有し、また、高温・高湿の状態でも長時間にわたる耐久性を示した。
【００５０】
実施例６
ジオキサジン化合物を実施例１及び２で得られた式（Ia）及び（Ib）で示されるそれぞれの化合物に変更して、実施例５と同様の方法により偏光膜を得た。得られた偏光膜のλmax は、それぞれ次のとおりであった。
【００５１】

【００５２】
実施例７
ジオキサジン化合物を実施例４に記載の式（Id）、（Ie）及び（If）で示されるそれぞれの化合物に変更して、実施例５と同様の方法により偏光膜を得た。得られた偏光膜は、高温・高湿の条件下での耐久性に優れていた。また、これらの変更膜のλmax は、それぞれ次のとおりであった。
【００５３】

【００５４】
【発明の効果】
本発明のジオキサジン化合物は、染料、特に偏光膜用の染料として、有用である。そしてこの化合物を含有する染料系偏光膜は、ヨウ素を用いた偏光膜に匹敵する高い偏光性能を示し、また耐久性、特に熱に対する耐久性及び湿熱条件下での耐久性に優れるので、各種液晶表示体、なかでも高い偏光性能と耐久性を必要とする屋外用途、特に車に搭載される用途、さらには各種環境で用いられる工業計器類の表示用途などに好適である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dioxazine compound useful as a dye, particularly a blue dye for a polarizing film, and a dye-based polarizing film containing the dioxazine compound.
[0002]
[Prior art]
The polarizing film is polarized on a polarizing film substrate such as a stretched and oriented polyvinyl alcohol film or a polyene film formed by orienting a polyene by dehydrochlorination of a polyvinyl chloride film or dehydration of a polyvinyl alcohol film. It is manufactured by containing iodine or a dichroic dye as an element. Among these, although the iodine-based polarizing film is excellent in initial polarization performance, it has a problem that its performance deteriorates in a high temperature and high humidity state because it is inferior in heat durability and water durability. In order to improve such durability, a method of treating with an aqueous solution containing formaldehyde or boric acid or a method of using a polymer film having low moisture permeability as a protective film is considered, but it is still sufficient. Absent.
[0003]
On the other hand, a dye-type polarizing film using a dichroic dye as a polarizing element is superior in durability to heat and water as compared with an iodine-type polarizing film, but generally has poor initial polarizing performance. In addition, in a neutral color polarizing film formed by adsorbing and orienting two or more dichroic dyes on a polymer film, the two polarizing films are stacked so that their orientation directions are orthogonal (orthogonal position). If there is color leakage of a specific wavelength in the visible wavelength range, the hue of the liquid crystal display may change in the dark state when the polarizing film is attached to the liquid crystal panel. Therefore, when a polarizing film is mounted on a liquid crystal display device, in order to prevent discoloration of the liquid crystal display device due to color leakage of a specific wavelength in the dark state, two or more dichroic dyes are adsorbed and oriented on the polymer film. In the neutral color polarizing film, the transmittance in the orthogonal position (orthogonal transmittance) in the visible region, particularly in the wavelength region of 400 to 700 nm, must be uniformly reduced. Therefore, in the production of a neutral color polarizing film in which two or more dichroic dyes are adsorbed and oriented on a polymer film, the performance and selection of dyes covering each wavelength are important.
[0004]
As blue dyes used in the production of the polarizing film, for example, JP-A-61-275703 and JP-A-4-212103 describe dioxazine compounds. However, the polarizing film containing the dioxazine compound has not sufficiently satisfied the needs of consumers in terms of performance.
[0005]
[Problems to be solved by the invention]
One object of the present invention is to provide a blue compound suitable for the production of a high-performance polarizing film. Another object of the present invention is to provide a high-performance polarizing film using this compound.
[0006]
The inventors of the present invention, particularly when used as a dye for a polarizing film, have good dyeability during production of the polarizing film, excellent polarizing performance, and excellent durability under high temperature and high humidity conditions. In addition, when a neutral color polarizing film is produced by adsorbing and orienting two or more dichroic dyes on a polymer film, a dye covering a relatively long wavelength region (500 to 700 nm) As a result of searching for a suitable compound, the inventors have found that a specific dioxazine compound is effective as a dye for a polarizing film, and completed the present invention.
[0007]
[Means for Solving the Problems]
That is, the present invention represents the following formula (I) when expressed in the form of a free acid.
[0008]

[0009]
[Wherein R is the following formula (R1) or (R2)
[0010]
-[A] -X- [C] (R1)
-[A] -X- [B] -Y- [C] (R2)
[0011]
Wherein [A] represents phenylene which may be substituted with one or two substituents selected from methyl and methoxy, or represents naphthylene having sulfo and a hydroxyl group, [B] Represents phenylene which may be substituted with 1 or 2 substituents selected from methyl and methoxy, [C] has 1 or 2 water-soluble groups selected from sulfo and carboxyl, Represents phenyl optionally substituted with a substituent selected from methyl, methoxy and hydroxyl, or represents naphthyl having 1 or 2 sulfos and further substituted with hydroxyl, X and Y are Each independently represents -N = N- or -CONH-]
Further, the present invention provides a dye-based polarizing film comprising the dioxazine compound in a polarizing film substrate.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the formula (I), R is a group represented by the above formula (R1) or (R2), and [A] in these formulas is phenylene or naphthylene having sulfo and a hydroxyl group, [B ] Is phenylene, [C] is phenyl having 1 or 2 water-soluble groups selected from sulfo and carboxyl, or naphthylene having 1 or 2 sulfo. The phenylene represented by [A] and [B] may be unsubstituted or may be substituted with one or two groups selected from methyl and methoxy. The phenyl represented by [C] has sulfo and / or carboxyl as described above, and may be further substituted with a group selected from methyl, methoxy and hydroxyl groups. The naphthyl represented by [C] has sulfo as described above, and may be further substituted with a hydroxyl group.
[0013]
From the viewpoint of dichroism, phenylene represented by [A] and [B] is advantageously 1,4-phenylene which is unsubstituted or substituted with the above-mentioned group, that is, p-phenylene. . Specifically, as the phenylene, the 1-position of phenylene represented by [A] is bonded to NH in formula (I), and the 1-position of phenylene represented by [B] is represented by formula (R2). 1,4-phenylene, 2-methyl-1,4-phenylene, 2-methoxy-1,4-phenylene, 3-methyl-1,4-phenylene, 3-methoxy-1,4 -Phenylene, 2,5-dimethoxy-1,4-phenylene, 2-methyl-5-methoxy-1,4-phenylene and the like.
[0014]
Further, as the naphthylene represented by [A], specifically, the 2-position is bonded to NH in the formula (I), and 5-hydroxy-7-sulfo-2,6-naphthylene, 8-hydroxy- Examples include 6-sulfo-2,7-naphthylene. When [A] is naphthylene having sulfo and a hydroxyl group, these sulfo and hydroxyl groups may be usually one each, and in this case, X to which naphthylene is bonded is usually -N = N-. .
[0015]
Examples of the phenyl represented by [C] include 2-, 3- or 4-sulfophenyl, 2-, 3- or 4-carboxyphenyl, 2,4- or 2,5-disulfophenyl, 2- Carboxy-4- or -5-sulfophenyl, 2-sulfo-4- or -5-methylphenyl, 3-sulfo-4-methylphenyl, 2-methyl-5-sulfophenyl, 2-sulfo-4- or- Examples include 5-methoxyphenyl, 3-sulfo-4-methoxyphenyl, 2-methoxy-5-sulfophenyl, 2-hydroxy-5-sulfophenyl, 3-hydroxy-4-carboxyphenyl, and the like. Thus, the phenyl represented by [C] has a total of one or two water-soluble groups selected from sulfo and carboxyl, and those having only one sulfo as a water-soluble group are suitable. is there. Even when the phenyl represented by [C] has a substituent in addition to sulfo and / or carboxyl, it is usually sufficient to have one substituent among methyl, methoxy and hydroxyl groups.
[0016]
Examples of the naphthyl represented by [C] include 5-, 6-, 7- or 8-sulfo-2-naphthyl, 4-, 5-, 6- or 7-sulfo-1-naphthyl, 6, 8-, 4,8- or 3,6-disulfo-2-naphthyl, 3,6- or 4,6-disulfo-1-naphthyl, 5-hydroxy-7-sulfo-2-naphthyl, 6-sulfo-8 -Hydroxy-2-naphthyl, 5-hydroxy-7-sulfo-1-naphthyl and the like. Even when the naphthyl represented by [C] has a hydroxyl group in addition to 1 or 2 sulfos, it is usually sufficient to have one hydroxyl group.
[0017]
Preferred examples of the group represented by R in the formula (I) include those represented by the following formulas.
[0018]

[0019]
In the formula, X and Y are as defined above, and m represents 1 or 2.
[0020]
The dioxazine compound represented by the formula (I) can be produced, for example, by the method described below. First, the following formula (II)
[0021]
R-NH ₂ (II)
[0022]
(Wherein R represents the above meaning)
Is reacted with phenyl chlorocarbonate by a conventional method to obtain the following formula (III)
[0023]

[0024]
(Wherein R represents the above meaning)
Is obtained. Then, when expressed in the form of a free acid with this carbamate compound, the following formula (IV)
[0025]

[0026]
A dioxazine compound represented by the formula (I) can be obtained by reacting the dioxazine intermediate compound represented by the formula (I) in an aqueous solvent at 20 to 60 ° C.
[0027]
The dioxazine compound represented by the formula (I) thus obtained can exist in a free acid form or a salt form. Examples of the salt include alkali metal salts such as lithium salts, sodium salts and potassium salts, ammonium salts, organic amine salts such as ethanolamine salts and alkylamine salts. When this compound is contained in the polarizing film substrate, it is usually preferable to use it in the form of a sodium salt.
[0028]
Moreover, when the dioxazine compound represented by the formula (I) is contained in a polarizing film substrate to form a polarizing film, the hue can be corrected and the polarizing performance can be improved by using it together with another organic dye. . The organic dye used in this case may be any dye as long as it has a high dichroism, and examples thereof include the following described in the color index.
[0029]
C eye direct yellow 12, 28 and 44,
C.I.Direct Orange 26, 39 and 107,
CI Direct Red 2, 31, 79, 81 and 247 etc.
[0030]
The dye-based polarizing film of the present invention is prepared by applying a dichroic dye comprising a compound represented by the formula (I) or further containing another organic dye to a polymer film as a polarizing film substrate by a known method. It can manufacture by making it contain. As this polymer film, for example, a film made of polyvinyl alcohol resin, nylon resin, polyester resin or the like is used. The polyvinyl alcohol-based resin mentioned here includes polyvinyl alcohol itself, which is a portion of polyvinyl acetate or a completely saponified product, polyvinyl acetate before saponification, ethylene / vinyl acetate (EVA) resin, and saponified EVA resin. Vinyl acetate and other copolymerizable monomers such as olefins such as ethylene and propylene, unsaturated carboxylic acids such as crotonic acid, acrylic acid, methacrylic acid and maleic acid, unsaturated sulfonic acids Further, copolymers with vinyl ethers and saponified products thereof, and polyvinyl formal and polyvinyl acetal obtained by modifying polyvinyl alcohol with aldehyde are also included. As the polarizing film substrate, a polyvinyl alcohol film, particularly a polyvinyl alcohol film, is preferably used from the viewpoint of the adsorptivity and orientation of the dye.
[0031]
When such a polymer film contains a dichroic dye, a method of dyeing the polymer film is usually employed. Staining can be performed, for example, as follows. First, a dichroic dye is dissolved in water to prepare a dye bath. The dye concentration in the dye bath is not particularly limited, but is usually selected from the range of 0.0001 to 10% by weight. Further, if necessary, a dyeing assistant may be used. For example, it is preferable to use 1 to 10% by weight of sodium sulfate in the dyeing bath. Dyeing is performed by immersing the polymer film in the dye bath thus prepared. The dyeing temperature is preferably 40 to 80 ° C. The orientation of the dichroic dye is performed by stretching a polymer film. As a stretching method, any known method such as a wet method or a dry method may be employed. The polymer film may be stretched before dyeing or after dyeing.
[0032]
The polymer film containing the dichroic dye and oriented is subjected to post-treatment such as boric acid treatment by a known method, if necessary. Such post-processing is performed for the purpose of improving the light transmittance, polarization degree, and durability of the polarizing film. The conditions for boric acid treatment vary depending on the type of polymer film used and the type of dye used, but generally the boric acid concentration in the boric acid aqueous solution is in the range of 1 to 15% by weight, preferably 5 to 10% by weight. And the treatment is carried out in a temperature range of 30 to 80 ° C., preferably 50 to 80 ° C. Further, if necessary, the fixing treatment may be performed together with an aqueous solution containing a cationic polymer compound.
[0033]
The dye-type polarizing film obtained in this way can be used as a polarizing plate by bonding a protective film excellent in optical transparency and mechanical strength on one or both sides. The material for forming the protective film may be those conventionally used. For example, in addition to a cellulose acetate film and an acrylic film, a fluororesin film such as a tetrafluoroethylene / hexafluoropropylene copolymer Polyester film, polyolefin film, polyamide film and the like are used.
[0034]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, these are illustrations and do not limit this invention at all. In the examples,% and parts are based on weight unless otherwise specified.
[0035]
Example 1
After dissolving 8 parts of sodium N- (p-aminobenzoyl) sulfanilate in 500 parts of water, adjusting the pH to 7-8 with 15% aqueous sodium carbonate solution at a temperature of 20-25 ° C. It was added dropwise over 30 minutes. After stirring at the same temperature and the same pH for 1 hour, the precipitated crystals were filtered to obtain an intermediate represented by the following formula (1).
[0036]

[0037]
Total amount of intermediate obtained and the following formula (2)
[0038]

[0039]
3 parts of the dioxazine intermediate compound represented by the above formula was added to 300 parts of water, and the mixture was stirred for 5 hours at a temperature of 15 to 20 ° C. while adjusting the pH to 11 to 12 with a 10% sodium hydroxide aqueous solution. The precipitated crystals were filtered, and the resulting cake was added to 400 parts of warm water at 60 ° C. to dissolve. After removing insolubles by filtration, 100 parts of ethanol was added to the filtrate to precipitate crystals again. The precipitated crystals were filtered to obtain a dioxazine compound represented by the following formula (Ia), and this compound exhibited λmax of 628 nm in an aqueous medium.
[0040]

[0041]
Example 2
By performing the same operation as in Example 1 using sodium 4-aminoazobenzene-4′-sulfonate instead of sodium N- (p-aminobenzoyl) sulfanilate used in Example 1, the following formula A dioxazine compound represented by (Ib) was obtained, which showed λmax 628 nm in an aqueous medium.
[0042]

[0043]
Example 3
After charging 10 parts of 4-amino-4 '-[N- (p-sulfophenyl) carbamoyl] azobenzene sodium salt into a mixed solution of 300 parts of N-methylpyrrolidone and 100 parts of water, at a temperature of 20 to 25 ° C, While adjusting the pH to 7 to 8 with a 15% aqueous sodium carbonate solution, 12 parts of phenyl chlorocarbonate was added dropwise over 30 minutes. After stirring at the same temperature and the same pH for 3 hours, the precipitated crystals were filtered to obtain an intermediate represented by the following formula (3).
[0044]

[0045]
The total amount of the obtained intermediate and 3 parts of the dioxazine intermediate compound of the formula (2) shown in Example 1 were added to 300 parts of water, and the pH was adjusted to 11 to 12 with a 10% aqueous sodium hydroxide solution at a temperature of 15 to 20 ° C. The mixture was stirred for 5 hours. Crystals precipitated by adding 500 parts of ethanol were filtered, and the obtained cake was added to 600 parts of warm water at 80 ° C. to dissolve. After removing insolubles by filtration, 200 parts of ethanol was added to the filtrate to precipitate crystals again. The precipitated crystals were filtered to obtain a dioxazine compound represented by the following formula (Ic), and this compound exhibited λmax of 647 nm in an aqueous medium.
[0046]

[0047]
Example 4
Dioxazine compounds represented by the following formulas (Id), (Ie), and (If) were obtained by changing the raw material compounds and performing operations according to Examples 1 to 3, respectively.
[0048]

[0049]
Example 5
A polyvinyl alcohol film (Kuraray Vinylon # 7500, Kuraray Co., Ltd.) having a thickness of 75 μm was stretched 5 times along a longitudinal axis to obtain a polarizing film substrate. While maintaining this polyvinyl alcohol film in a tension state, the concentration of the dioxazine compound represented by the formula (Ic) obtained in Example 3 was 0.025% and the concentration of mirabilite as a dyeing assistant was 2.0%. It was immersed in an aqueous solution at ° C. Next, it was immersed in a 7.5% boric acid aqueous solution at 65 ° C. for 5 minutes, then taken out, washed with 20 ° C. water for 20 seconds, and dried at 50 ° C. to obtain a polarizing film. The obtained polarizing film had a λmax of 640 nm, and this polarizing film had a high degree of polarization, and exhibited durability over a long period of time even at high temperatures and high humidity.
[0050]
Example 6
A polarizing film was obtained in the same manner as in Example 5 except that the dioxazine compound was changed to the respective compounds represented by the formulas (Ia) and (Ib) obtained in Examples 1 and 2. Λmax of the obtained polarizing film was as follows.
[0051]

[0052]
Example 7
A polarizing film was obtained in the same manner as in Example 5 except that the dioxazine compound was changed to each compound represented by the formula (Id), (Ie) and (If) described in Example 4. The obtained polarizing film was excellent in durability under high temperature and high humidity conditions. In addition, λmax of these modified films was as follows.
[0053]

[0054]
【The invention's effect】
The dioxazine compound of the present invention is useful as a dye, particularly as a dye for a polarizing film. The dye-based polarizing film containing this compound exhibits high polarization performance comparable to that of a polarizing film using iodine, and is excellent in durability, particularly durability against heat and durability under wet heat conditions. It is suitable for display bodies, especially for outdoor use that requires high polarization performance and durability, especially for use in vehicles, and for display of industrial instruments used in various environments.

Claims (7)

When expressed in the form of the free acid, the following formula (I)

[Wherein R is the following formula (R1) or (R2)
-[A] -X- [C] (R1)
-[A] -X- [B] -Y- [C] (R2)
Wherein [A] represents phenylene which may be substituted with one or two substituents selected from methyl and methoxy, or represents naphthylene having sulfo and a hydroxyl group, [B] Represents phenylene which may be substituted with 1 or 2 substituents selected from methyl and methoxy, [C] has 1 or 2 water-soluble groups selected from sulfo and carboxyl, Represents phenyl optionally substituted with a substituent selected from methyl, methoxy and hydroxyl, or represents naphthyl having 1 or 2 sulfos and further substituted with hydroxyl, X and Y are Each independently represents -N = N- or -CONH-]
A dioxazine compound represented by the formula: The dioxazine compound according to claim 1, wherein [A] and [B] are each independently 1,4-phenylene which is unsubstituted or substituted with one or two substituents selected from methyl and methoxy. [C] has one sulfo and no other substituent, or is a phenyl further substituted with a substituent selected from methyl, methoxy and hydroxyl, or one or two sulfo The dioxazine compound according to claim 1, wherein the dioxazine compound is a naphthyl having a substituent and no other substituent, or further substituted with a hydroxyl group. R is the following formula

(Wherein X and Y are as defined in claim 1, m represents 1 or 2)
The dioxazine compound of Claim 1 shown by either. A dye-based polarizing film comprising the dioxazine compound according to any one of claims 1 to 4 in a polarizing film substrate. Furthermore, the dye type polarizing film of Claim 5 containing the organic dye different from this dioxazine compound. The dye-based polarizing film according to claim 5 or 6, wherein the polarizing film substrate is a film made of a polyvinyl alcohol-based resin.