JP4265085B2 - Optical anisotropic body, manufacturing method thereof, polarizing plate and liquid crystal display device using the same - Google Patents

Description

上記組成物を密閉容器に投入し、加圧下で８０℃に保温し撹伴しながら完全に溶解してドープ組成物を得た。次に、このドープ組成物を安積濾紙社製の安積濾紙Ｎｏ．２４４を使用して濾過し、その後冷却して３５℃に保ちステンレスバンド上に均一に流延し、剥離が可能になるまで溶媒を蒸発させたところで、ステンレスバンド上から剥離した。剥離後の残留溶媒量５０質量％〜５質量％の間の乾燥ゾーン内でテンターによって幅保持しながら乾燥を進行させ、さらに、多数のロールで搬送させながら残留溶媒量１質量％以下となるまで乾燥させ、膜厚１１０μｍの支持体１〜４を作製した。
【００８８】
なお、各支持体の作製に用いたセルロースアセテートは、以下の通りである。
支持体１：アセチル基置換度２．９２のセルロースアセテート（数平均分子量２０００００）
支持体２：アセチル基置換度２．６５のセルロースアセテート（数平均分子量１７００００）
支持体３：アセチル基置換度２．９２のセルロースアセテート（数平均分子量２０００００）とアセチル基置換度２．４５のセルロースアセテート（数平均分子量１０００００）を混合し、混合後の平均アセチル基置換度が２．６５となるように調整した。
【００８９】
支持体４：アセチル基置換度２．５１のセルロースアセテート（数平均分子量１５００００）とアセチル基置換度２．８６のセルロースアセテート（数平均分子量１８００００）を混合し、混合後の平均アセチル基置換度が２．６５となるように調整した。
【００９０】
《配向膜、液晶膜及び転写層の塗設》
上記作製した支持体１〜４上に、表１に示す組み合わせで、下記配向膜１、２及び液晶膜１〜３あるいは転写層１を塗設し、光学異方体試料Ａ〜Ｏを作製した。
【００９１】
【表１】

【００９２】
（配向膜１の塗設）
表１に示した各支持体上に、０．１μｍのゼラチン薄膜を塗設し、ついで直鎖アルキル変性ポリビニルアルコール（ＭＰ２０３ クラレ社製）を乾燥膜厚が０．２μｍとなるように塗布した。これを８０℃温風にて乾燥させた後、ラビング処理を行って、配向膜１を形成した。
【００９３】
（配向膜２の塗設）
表１に示した各支持体上に、サンエバー５２９１（日産化学社製）を乾燥膜厚が０．１μｍとなるように塗布した。これを１１０℃３時間乾燥させた後、ラビング処理を行って、配向膜２を形成した。
【００９４】
（液晶層１の塗設）
表１に示した各基板構成の配向膜上に、液晶性ディスコティック化合物ＬＣ−１を１．６ｇ、フェノキシジエチレングリコールアクリレート（Ｍ１０１ 東亜合成社製）０．４ｇ、セルロースアセテートブチレート（ＣＡＢ５３１−１ イーストマンケミカル社製）０．０５ｇ及び光重合開始剤（イルガキュア−９０７チバ・ガイギー社製）０．０１ｇを、３．６５ｇのメチルエチルケトンに溶解した塗布液を、ワイヤーバーで塗布した。次いで、これを金属の枠に貼りつけて固定し、乾燥と配向のために１３０℃の恒温槽中で３分間加熱し、デイスコティック化合物を配向させた。次に、試料を窒素雰囲気下で高圧水銀灯を用いて照度１０ｍＷ／ｃｍ²で１３０℃下３０秒間紫外線を照射し、架橋反応により配向を固定化した。室温まで放冷して、ディスコティック化合物を含む液晶層１を形成して各光学異方体試料を作製した。液晶層１の膜厚は１．８μｍであった。
【００９５】
（液晶層２の塗設）
表１に示した各基板構成の配向膜上に、５ｇのＬＣ−２を４５ｇのクロロホルムに溶解させ調製した１０質量％溶液を印刷法により塗布し、１１０℃のホットプレート上で乾燥し、オーブンで配向のために１１０℃で３０分間熱処理を施した後、室温中に取り出して冷却して、ＬＣ−２を配向固定化し、各光学異方体試料を作製した。なお、ＬＣ−２のガラス転移温度は９０℃である。液晶層２の膜厚は２．０μｍであった。
【００９６】
（液晶層３の塗設）
表１に示した各基板構成の配向膜上に、ＬＣ−３を１．６ｇ、フェノキシジエチレングリコールアクリレート（Ｍ１０１ 東亜合成社製）０．４ｇ、及び光重合開始剤（イルガキュア−９０７ チバ・ガイギー社製）０．０１ｇを、３．６５ｇのメチルエチルケトンに溶解して得られた塗布液を、ワイヤーバーで塗布した。ついで、それに金属の枠を貼りつけて固定して乾燥した後、配向のために１２０℃の恒温槽中で３分間加熱処理を施し、液晶化合物を配向させた。次に高圧水銀灯を用いて窒素雰囲気下で、照度１０ｍＷ／ｃｍ²で３０秒間、その後１２０℃で１０秒間紫外線を照射し、架橋反応により液晶化合物の配向を固定化し、室温まで放冷して、各光学異方体試料を作製した。液晶層３の膜厚は０．８μｍであった。
【００９７】
【化１】

【００９８】
（転写層１の塗設）
耐熱性ポリイミドフィルム上にサンエバー５２９１（日産化学社製）を乾燥膜厚が０．１μｍとなるように塗布した。これを１１０℃で３時間乾燥させた後、ラビング処理を行い、配向膜を得た。ついで、５ｇのＬＣ−４を４５ｇのクロロホルムに溶解させた１０質量％溶液からなる液晶層を配向膜上に塗布した。ついで、８０℃のホットプレート上で乾燥し、オーブンで配向のために２３０℃で９０分間熱処理を施した後、室温中に取り出して冷却して、ポリイミドフィルム上にＬＣ−４の配向を固定化した。なお、用いたＬＣ−４のガラス転移温度は１９０℃である。次いで、紫外線硬化型の接着剤をこの液晶層上に塗布した後、表１に記載の支持体１〜３にラミネートし、高圧水銀灯の光を照射して接着剤を硬化させた後、ポリイミドフィルムを剥がして除去した。この時、液晶層は接着剤を介して支持体上に形成されている。接着層は光学的には等方性であった。液晶層の厚さは１．９μｍであった。
【００９９】
以上のようにして作製した光学異方体試料Ａ〜Ｏを６０℃で２モル／Ｌの水酸化ナトリウム水溶液中に２分間浸漬し水洗した後、１００℃で１０分間乾燥し光学異方体アルカリ処理試料Ａ〜Ｏを作製した。
【０１００】
《偏光板の作製》
厚さ１２０μｍのポリビニルアルコールフィルムを沃素１質量部、ホウ酸４質量部を含む水溶液１００質量部に浸漬し、５０℃で４倍に延伸して偏光膜を作製した。この偏光膜の片面に上記と同様のアルカリ処理を施した支持体１を、また、反対側の面には、上記作製した光学異方体アルカリ処理試料Ａ〜Ｏをそれぞれ偏光軸に対して液晶パネルの視野角が拡大できる貼り合わせ角度となるように調整して、液晶化合物の塗布面が偏光膜とは反対側に位置するように完全鹸化型ポリビニルアルコール５％水溶液を粘着剤として貼り合わせ偏光板試料Ａ〜Ｏを作製した。また、比較偏光板として偏光膜の両面にアルカリ処理を施した支持体１を同様の方法にて貼り合わせた比較偏光板も同時に作製した。
【０１０１】
《各試料の特性評価》
（支持体のΔＮ値の測定）
上記作製した支持体１〜４について、まずアッベ式屈折率計を用いてフィルム全体の平均屈折率を測定した。ついで、自動複屈折計ＫＯＢＲＡ−２１ＡＤＨ（王子計測機器社製）を用いて、２３℃、５５％ＲＨの環境下で、波長が５９０ｎｍにおける３次元屈折率測定を行い、先に測定したアッベ式屈折率計で測定した平均屈折率値を入力し、リターデーションの角度特性から屈折率ｎｘ、ｎｙ、ｎｚを求めた。なお、この３次元屈折率は、試料のリターデーション特性により求めるものである。以上により測定したｎｘ、ｎｙ及びｎｚを用いて、前記式１より、各支持体のΔＮ値を算出し、得られた結果を表２に示す。
【０１０２】
【表２】

【０１０３】
表２の結果より明らかなように、本発明の支持体２〜４は、式１で規定したΔＮ値として高い値を有しており、薄膜化及び軽量化の観点から好ましい特性であることが判る。
【０１０４】
（光学異方性の評価）
以下に示す方法により、光学異方体試料Ａ〜Ｏの光学異方性を確認した。
【０１０５】
偏光板を直交ニコルの状態として、その間に各光学異方体試料を設置し、各光学異方体試料の光学異方性を目視および１００倍の光学顕微鏡で観察した結果、すべて試料が良好な光学異方性を有し、モノドメインであることを確認した。
【０１０６】
（視野角の評価）
ＮＥＣ社製ＬＡ−１５２９ＨＭ型のＴＦＴ−ＴＮ液晶パネルの偏光板を剥がし、前記作製した比較偏光板よりも視野角が広がるような条件で、上記作製した各偏光板試料Ａ〜Ｏを剥がした偏光板の偏光軸と一致する方向で液晶パネルに張り付けた。各々の偏光板試料は、偏光子と液晶パネルとの間に配置し、かつ液晶層が各々偏光膜の外側になるように貼付けた。これらの偏光板の貼付けは、各々の試料を液晶パネルに対してバックライト側と画像観察面側のそれぞれの面に貼付けた。以上のようにして作製した、それぞれ組み込んだ偏光板番号に対応した各液晶パネル試料Ａ〜Ｏについて、パソコンでモニターを駆動し、白色／黒色表示時のコントラスト比をＥＬＤＩＭ社製のＥｚ−Ｃｏｎｔｒａｓｔを用いて測定し、上下左右について、コントラストが１０以上を示す液晶パネルの法線方向からの角度をそれぞれ測定し、それを視野角と定義した。以上の方法により得られた結果は以下の通りである。
【０１０７】
液晶パネル試料Ａに対して、液晶パネル試料Ｄ、Ｇは視野角が拡大した。
液晶パネル試料Ｂに対して、液晶パネル試料Ｅ、Ｈは視野角が拡大した。
【０１０８】
液晶パネル試料Ｃに対して、液晶パネル試料Ｆ、Ｉは視野角が拡大した。
液晶パネル試料Ｊに対して、液晶パネル試料Ｋ、Ｌは視野角が拡大した。
【０１０９】
液晶パネル試料Ｍに対して、液晶パネル試料Ｎ、Ｏは視野角が拡大した。
以上の結果より、比較試料に対し高いΔＮ値を有する本発明の支持体を用いた液晶パネル試料は、支持体の厚さが同一である時、視野角が拡大できる点で優れていることが判る。このことは、比較試料と同等の光学特性（視野角）を得る場合、本発明の支持体は、比較試料に対し、薄膜設計が容易にできることを示している。
【０１１０】
（リターデーションの測定）
上記作製した各光学異方体試料について、自動複屈折率計ＫＯＢＲＡ−２１ＡＤＨ（王子計測機器社製）を用いて、各々の光学異方体試料の遅相軸における角度（−４０°〜＋４０°の範囲、測定は１０°毎）依存性のリターデーションを測定し、同時に支持体１〜４についても測定した。液晶層が存在する光学異方体試料の測定値から、対応する支持体試料の各角度成分のリターデーションの差をそれぞれ求めた結果、光学異方体試料Ｂ、Ｃ、Ｅ、Ｆ、Ｈ、Ｉ、Ｋ、Ｌ、Ｎ、Ｏは液晶層のリターデーションの最大値を示す角度が、試料の面に対する法線方向（０°）からずれており、光学異方層の液晶化合物の分子が傾いていることがわかった。また、最大値を示す角を中心として±側の角度に対するリターデーションの変化が左右非対称であることから、液晶化合物の分子はすべての試料で厚さ方向に対して角度が変化していることがわかる。
【０１１１】
ついで、上記作製した各光学異方体試料について、自動複屈折率計ＫＯＢＲＡ−２１ＡＤＨ（王子計測機器社製）を用いて、各々の光学異方体試料の進相軸における角度（−４０°〜＋４０°の範囲、測定は１０°毎）依存性のリターデーションを測定し、同様に支持体１〜４についても測定した。液晶層が存在する光学異方体試料から、それぞれ対応する支持体試料の各角度成分のリターデーションの差を求めた結果、光学異方体試料Ａ、Ｄ、Ｇ、Ｊは、液晶層のリターデーションの最小値を示す角度が試料の面に対する法線方向（０°）からずれており、光学異方層の液晶化合物の分子が傾いていることがわかった。また、最小値を示す角度を中心をして±側の角度のリターデーションの変化が左右非対称であり、かつリターデーションの最小値が０でないことから、液晶化合物の分子はすべての試料で厚さ方向に対して角度が変化していることがわかる。
【０１１２】
更に、光学異方体試料Ｆ、Ｉに対して、製造時のラビング条件を適宜変更して液晶化合物の傾斜角が０°となる光学異方体試料Ｆ′、Ｉ′を作り、それを組み込んだ偏光板試料Ｆ′、Ｉ′を作製して、上記と同様に評価を行った結果、液晶層の液晶化合物の配向に傾斜角を有する偏光板試料Ｆ、Ｉの方が、傾斜角が０°である偏光板試料Ｆ′、Ｉ′に比較し、視野角が拡大し、良好な結果を示した。これより、偏光板においては、液晶化合物の配向に傾斜角を有する光学異方体からなる本発明の偏光板が優れていることがわかった。
【０１１３】
実施例２
実施例１で作製した光学異方体試料Ｃ、Ｆ、Ｉにおいて、最外層の液晶層３上に、すでに設置した配向層２と直交する角度で新たな配向膜２を設置し、ラビング処理を行った。更に、その上にすでに設置した液晶層３と同一の組成を有する新たな液晶層３を設置し、同様に配向を固定化し、それを偏光板に組み入れた偏光板試料Ｃ″、Ｆ″、Ｉ″を作製した。作製した偏光板を用いて実施例１と同様の方法で視野角を評価した結果、偏光板試料Ｆ″、Ｉ″は偏光板試料Ｃ″に比較し、視野角が広いことが確認できた。この結果、複数の液晶層を有する光学異方体においても、本発明に係る構成の試料は、視野角特性が優れていることが判った。
【０１１４】
実施例３
実施例１で作製した本発明の支持体２の厚み方向でのリターデーション値（Ｒｔ値）を下記に示す方法で測定した結果、Ｒｔ値は１２６．６ｎｍ（厚さ１１０μｍ）であった。次いで、比較試料である支持体１について、製膜時の支持体膜厚を適宜変更して、支持体２と同一のＲｔ値を有する支持体１′を作製した。得られた支持体１′は、Ｒｔ値：１２６．５ｎｍ、厚さ：１８１μｍであった。
【０１１５】
〈厚み方向リターデーション値（Ｒｔ値）の測定方法〉
自動複屈折計ＫＯＢＲＡ−２１ＡＤＨを用いて、２３℃、５５％ＲＨの環境下で、波長が５９０ｎｍにおいて、３次元屈折率測定を行い、屈折率ｎｘ、ｎｙ、ｎｚを求め、下記式に従って、リターデーション値（Ｒｔ値）を算出した。
【０１１６】
Ｒｔ値＝（（ｎｘ＋ｎｙ）／２−ｎｚ）×ｄ
なお、ｎｘ、ｎｙ及びｎｚは、ΔＮ値を求める前記式１のそれぞれと同義である。ただし、ｄはフィルムの厚み（ｎｍ）を表す。
【０１１７】
以上の結果から、本発明の光学異方体を構成する支持体は、目的の光学特性（Ｒｆ値）を得るために、比較試料に対し薄膜化できる点で優れていることがわかる。
【０１１８】
次いで、支持体−１′を用いて実施例１における偏光板試料Ｆと同様にして偏光板１′を作製し、実施例１記載の視野角の評価方法に則り評価を行った結果、偏光板１′を備えた液晶パネルは、偏光板Ｆを備えた本発明の液晶パネルとほぼ同じ視野角に拡大した。しかしながら、支持体１′で作製した偏光板は、偏光膜の反対面側に張り付けた支持体１と厚さが大幅に異なり、そのため表裏面のカールバランスが取れず湾曲を起こし、扱い易さの点で本発明の偏光板よりも劣っていることが判明した。
【０１１９】
実施例４
実施例１で作製した支持体１〜４で用いた紫外線吸収剤である２−〔５−クロロ（２Ｈ）−ベンゾトリアゾール−２−イル〕−４−メチル−６−（ｔｅｒｔ−ブチル）フェノール（１ｋｇ）と２−〔２Ｈ−ベンゾトリアゾール−２−イル〕−４、６−ジ−ｔｅｒｔ−ペンチルフェノール（１ｋｇ）に変えて２−ヒドロキシ−４−ベンジルオキシベンゾフェノンを２ｋｇ添加して同様に支持体を作製し、実施例１と同様の方法で液晶パネルを作製し視野角の評価を行った結果、実施例１の結果と同様に、本発明の試料は、比較試料に対して視野角性能が優れていることが確認できた。
【０１２０】
【発明の効果】
本発明により、光学異方体の支持体面内の平均屈折率に対して厚さ方向の屈折率の差が大きい高度な光学特性を有する支持体上に液晶層を設置した光学異方体およびその製造方法を提供することができ、更には、薄膜化され、視野角の拡大できる光学異方体およびその製造方法、それを備えた偏光板及びそれらを備えた液晶表示装置を提供することができた。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polarizing plate used for a liquid crystal display device, and more particularly to a protective film for a polarizing plate.
[0002]
[Prior art]
In recent years, personal computers have become multimedia, and color display systems have become common in laptop personal computers. In laptop computers, STN liquid crystal displays and TFT liquid crystal displays are mainly used as color display methods.
[0003]
Since the STN liquid crystal display is a display element using a birefringence mode, it is colored due to a phase difference generated in the liquid crystal, and there is a big problem that monochrome display is impossible. In order to solve such a problem, a D-STN method (a method using a liquid crystal cell for compensation) has been tried. However, in this method, the process is reversed from the viewpoint of “thin and light” which is a characteristic of a liquid crystal display. In addition, the manufacturing of the compensation liquid crystal cell has the disadvantages that high accuracy is required and the yield is poor.
[0004]
As a method for solving these problems, various proposals have been made. For example, Japanese Patent Laid-Open No. 63-149624 proposes an F-STN method using a stretched resin film, and Japanese Patent Laid-Open No. 3-87720, No. 4-333019 proposes a method of color compensation using a film in which a liquid crystalline polymer is twisted and aligned in order to maintain the compensation performance of the D-STN system and reduce its mass and thickness. Has been. The retardation compensation plate of this liquid crystal display is composed of a translucent substrate, an alignment film formed on the substrate, and a liquid crystal polymer layer fixed on the alignment film in a twisted alignment state.
[0005]
Furthermore, recently, as a viewing angle compensation for TFT and TN liquid crystal displays, as disclosed in JP-A-7-191217, discotic liquid crystal films are arranged on the upper and lower surfaces of the liquid crystal cell, Attempts have been made to improve viewing angle characteristics. The TN type liquid crystal display compensator is formed on a translucent substrate and the same substrate as the phase difference compensator of the liquid crystal display described in JP-A-3-87720 and JP-A-4-333919. And a liquid crystal alignment layer formed on the alignment film.
[0006]
As described above, in recent years, in STN liquid crystal displays, TFTs, and TN liquid crystal displays, there has been a demand for optical films having a higher level of compensation performance than before. Has come to be considered.
[0007]
An optical anisotropic body is used in a method of attaching to a liquid crystal display member. From such a viewpoint, a transparent resin film is often used as a support for the optical anisotropic body, and in particular, the viewing angle characteristics of a liquid crystal display are improved. For this purpose, it has been demanded to develop a support having a large difference in refractive index in the thickness direction with respect to the average refractive index in the support surface. In addition, if an optical anisotropic body with the necessary retardation for optical compensation of a display is developed, the difference in refractive index with the support is small, so there is a constraint that the support must be designed to be thick. Have. In particular, liquid crystal displays are required to be small and light, and the development of light and thin optical anisotropic bodies is eagerly desired.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and its purpose is to provide a support having advanced optical characteristics in which the difference in refractive index in the thickness direction is large with respect to the average refractive index within the support surface of the optical anisotropic body. An optically anisotropic body having a liquid crystal layer disposed thereon and a method for producing the same, and further, an optically anisotropic body that is thinned and capable of expanding a viewing angle, a method for producing the same, a polarizing plate provided with the same An object of the present invention is to provide a liquid crystal display device including them.
[0009]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following constitution.
[0010]
1. In an optical anisotropic body having an optical anisotropic layer on a transparent support, the support has a substitution degree of acetyl group.2.55more than2.70The following celluloseesterresinIsAn optical anisotropic body characterized by that.
[0011]
2. An optical anisotropic body having an optical anisotropic layer on a transparent support, wherein the support is cellulose having an acetyl group substitution degree of 2.40 or more and 3.00 or less.esterTwo or more kinds of resins are mixed, and the average degree of acetyl group substitution after mixing is2.55more than2.70The following celluloseesterresinIsAn optical anisotropic body characterized by that.
[0012]
3.The optical anisotropic body according to 1 or 2, wherein the support contains a plasticizer and satisfies the following formula 1.
Formula 1
When defining ΔN value = (nx + ny) / 2−nz,
1.0 × 10 -3 ≦ ΔN ≦ 1.4 × 10 -3
[In the formula, nx represents the refractive index of the film in the casting direction, ny represents the refractive index of the film in the direction perpendicular to the casting direction (width direction), and nz represents the refractive index of the film in the thickness direction. ]
[0013]
4). 4. The optical anisotropic body as described in any one of 1 to 3 above, wherein the optical anisotropic layer contains a polymerizable discotic liquid crystal compound.
[0014]
5). In producing the optical anisotropic body described in the above item 4, an organic solvent solution containing a polymerizable discotic liquid crystal compound is prepared, and after applying and drying the solution, the temperature is adjusted for alignment, A method for producing an optical anisotropic body, wherein a curing reaction is carried out by irradiation to fix the orientation.
[0015]
6). 4. The optical anisotropic body according to any one of 1 to 3 above, wherein the optical anisotropic layer contains a polymer liquid crystal compound.
[0016]
7. In producing the optical anisotropic body described in the above item 6, an organic solvent solution containing a polymer liquid crystal compound is prepared, and the solution is applied and dried, and then the temperature for alignment is higher than the glass transition temperature of the liquid crystal compound. A method for producing an optical anisotropic body, characterized by adjusting and then lowering the temperature below the glass transition temperature to fix the orientation.
[0018]
8). 4. The optical anisotropic body as described in any one of 1 to 3 above, wherein the optical anisotropic layer contains a low-molecular polymerizable liquid crystal compound having positive birefringence.
[0019]
9. Said8 termsIn producing the described optical anisotropic body, an organic solvent solution containing a low-molecular polymerizable liquid crystal compound having positive birefringence is prepared, the solution is applied and dried, and then the temperature is adjusted for the alignment of the liquid crystal compound. A method for producing an optical anisotropic body, characterized in that the curing is carried out by irradiation with actinic rays and the orientation is fixed.
[0020]
10. The optically anisotropic layer is composed of a plurality of layers.8The optical anisotropic body described in the item.
[0022]
11. The above-mentioned 4, 6, characterized in that the orientation based on the liquid crystal compound contained in the optically anisotropic layer is substantially uniform and the orientation angle is oblique with respect to the support surface.8, 10The optically anisotropic body of any one of claim | items.
[0023]
12 1 to 4, 6, wherein the plasticizer is 2 to 15% by mass and the ultraviolet absorber is 0.01 to 3% by mass relative to the resin constituting the support.8, 10, 11The optically anisotropic body of any one of claim | items.
[0024]
13. The ultraviolet absorber is a benzotriazole derivative or a benzophenone derivative,12 termsThe optical anisotropic body described.
[0026]
14 The thickness of the support is from 35 μm to 150 μm,Any one of 1-4, 6, 8, 10-13The optical anisotropic body described.
[0027]
15. The polarizing plate protective film is the above 1-4, 6,8, 10-14A polarizing plate, which is the optical anisotropic body according to any one of the items.
[0028]
16. Said15A liquid crystal display device using the polarizing plate according to the item.
[0029]
First, the support used in the optical anisotropic body of the present invention will be described.
In the invention according to claim 1, in the optical anisotropic body having the optical anisotropic layer on the transparent support, the support is a cellulose ester resin having a substitution degree of acetyl group of 2.50 or more and 2.86 or less. Is a feature.
[0030]
In the invention according to claim 2, the support is a mixture of two or more cellulose ester resins having a substitution degree of acetyl group of 2.40 or more and 3.00 or less, and the average substitution degree of acetyl group after mixing is 2.50. It is characterized by being a cellulose ester resin of 2.86 or less.
[0031]
Furthermore, in the invention according to claim 3, the support has a cellulose ester resin having a substitution degree of at least one acetyl group of 2.60 or more and 3.00 or less and a substitution degree of at least one acetyl group of 2.40 or more. It is characterized in that it is a cellulose ester resin having an average acetyl group substitution degree of 2.50 or more and 2.86 or less after mixing with a cellulose ester resin of less than 2.60.
[0032]
A support made of a cellulose ester resin having an acetyl group substitution degree or an average acetyl group substitution degree of 2.5 or more and 2.86 or less is an optical having a high difference between the refractive index in the thickness direction and the average refractive index of the film surface. Characteristics can be obtained. By using a cellulose ester film in which the degree of substitution is kept low, it can be made thinner if the same optical characteristics are obtained as compared with a cellulose triacetate film having a high degree of acetyl group substitution. In particular, as a support for an optical anisotropic body excellent in viewing angle characteristics, the optical compensation ability required for a display is different, but it can be designed by appropriately adjusting the optical characteristics of the liquid crystal layer and the support. The preferable range of the acetyl group substitution degree or the average acetyl group substitution degree of the support according to the present invention is 2.55 to 2.70. If the substitution degree of the acetyl group is too small, the heat and moisture resistance may be poor. The cellulose ester resin according to the present invention can be synthesized, for example, by the method described in JP-A-10-45804. Moreover, the measuring method of the substitution degree of the acetyl group in this invention can be measured by ASTM-D817-96 (test methods, such as a cellulose acetate).
[0033]
A cellulose ester having an acetyl group substitution degree of 2.50 or more and 2.86 or less is an acetyl group in which a hydroxyl group of cellulose is substituted with a predetermined substitution degree by a conventional method. The number average molecular weight of the cellulose ester is preferably from 70,000 to 300,000, more preferably from 80,000 to 200,000, in order to obtain a preferable mechanical strength.
[0034]
The cellulose ester having an acetyl group substitution degree of 2.60 or more and 3.00 or less is an acetyl group in which a hydroxyl group of cellulose is substituted with a predetermined substitution degree by a conventional method. The number average molecular weight of the cellulose ester is preferably from 70,000 to 300,000, more preferably from 80,000 to 200,000, in order to obtain a preferable mechanical strength.
[0035]
The cellulose ester having an acetyl group substitution degree of 2.40 or more and less than 2.60 is one obtained by substituting a hydroxyl group of cellulose with an acetyl group to a predetermined substitution degree by a conventional method. The number average molecular weight of the cellulose ester is preferably from 70,000 to 300,000, more preferably from 80,000 to 200,000, in order to obtain a preferable mechanical strength.
[0036]
As the cellulose ester of the present invention, either cellulose triacetate synthesized from cotton linter or cellulose triacetate synthesized from wood pulp can be used alone or in combination. It is preferable to use a large amount of cellulose ester synthesized from a cotton linter that has good releasability from a belt or drum during film formation because of high productivity efficiency. The ratio of cellulose ester synthesized from cotton linter is 60% by mass or more, and since the effect of peelability becomes remarkable, 60% by mass or more is preferable, more preferably 85% by mass or more, and further, it can be used alone. Most preferred.
[0037]
In the invention according to claim 16, the support used for the optical anisotropic body of the present invention is such that nx is the refractive index in the casting direction of the film, ny is the refractive index of the film in the direction perpendicular to the casting direction (width direction). , Nz is the refractive index of the film in the thickness direction, and 1.0 × 10 is defined as ΔN value = (nx + ny) / 2−nz^-3≦ ΔN ≦ 1.4 × 10^-3It is the feature to satisfy. The invention according to claim 17 is characterized in that the thickness of the support is not less than 30 μm and not more than 150 μm under the above conditions. Outside these ranges, the product (retardation) of ΔN and the thickness of the support is not preferable because the target performance for optically compensating the liquid crystal panel cannot be obtained, or the optical anisotropic body becomes extremely thick. Including the viewpoint of reducing the weight of the polarizing plate, the thickness of the support is more preferably from 35 μm to 105 μm.
[0038]
An ordinary refractometer can be used to measure the refractive index of the entire support. After measuring the total refractive index, using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments Co., Ltd.), measuring the three-dimensional refractive index in an environment of 23 ° C. and 55% RH at a wavelength of 590 nm And values are obtained by obtaining the refractive indexes nx, ny, and nz.
[0039]
Next, the optical anisotropic body of the present invention will be described.
The optically anisotropic layer as used in the present invention refers to a layer in which the liquid crystal compound is aligned or in a state where the aligned state is fixed by a temperature difference or a chemical reaction. Moreover, the optically anisotropic body as used in the field of this invention means what was comprised in the form which has an optically anisotropic layer and a transparent support body, or further contains an intermediate | middle layer in the optically anisotropic layer and the transparent support body.
[0040]
When applying a liquid crystal compound and obtaining optical anisotropy, it is achieved by installing an alignment film on a transparent support and applying and aligning the liquid crystal compound thereon. Further, as a method for aligning a liquid crystal compound without using an alignment film in the liquid crystal layer, a method in which an electric field or a magnetic field is applied by heating to a temperature at which the liquid crystal compound exhibits liquid crystallinity can be given. Furthermore, the orientation state can also be obtained by inclining the substrate in a method of blowing hot air or in a liquid crystal temperature range and flowing a liquid crystalline compound. Among these, it is preferable to install an alignment film and perform rubbing treatment for ease of production.
[0041]
Here, the alignment film will be described. Specific examples of the alignment film include the following resins and substrates, but are not limited thereto. For example, polyimide, polyamideimide, polyamide, polyetherimide, polyetheretherketone, polyetherketone, polyketonesulfide, polyethersulfone, polysulfone, polyphenylenesulfide, polyphenyleneoxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacetal , Polycarbonate, polyarylate, acrylic resin, polyvinyl alcohol, polypropylene, cellulosic plastics, epoxy resin, phenol resin, and the like.
[0042]
The alignment film can be obtained by applying an alignment material on the transparent resin substrate of the present invention and drying to form a layer, followed by rubbing treatment. For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of the LCD can be used. That is, a method of obtaining alignment by rubbing the surface of the alignment film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. In general, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are flocked on average.
[0043]
In addition, a polyimide film (preferably fluorine atom-containing polyimide) widely used for alignment of liquid crystal compounds is also preferable as the alignment film. This is obtained by applying a polyamic acid (for example, LQ / LX series manufactured by Hitachi Chemical Co., Ltd., SE series manufactured by Nissan Chemical Co., Ltd.) on a transparent resin substrate, followed by heat treatment and rubbing. Alternatively, a photo-alignment film that is not rubbed may be used.
[0044]
Next, the liquid crystal compound used in the present invention will be described.
The invention according to claim 4 is characterized in that the optically anisotropic layer contains a polymerizable discotic liquid crystal compound. When the liquid crystalline compound in the present invention is a compound having a discotic structural unit, for example, Japanese Patent Registration No. 2587398, No. 2640083, No. 2641086, No. 2692033, No. 2692035, No. 2767382, No. 2747789, The compounds described in U.S. Pat. No. 2,866,372 can be used, but are not limited thereto.
[0045]
The invention according to claim 6 is characterized in that the optically anisotropic layer contains a polymer liquid crystal compound. When the liquid crystalline compound in the invention is a polymer liquid crystal compound, for example, Japanese Patent Registration No. 2592694, No. 2687035, No. 2711585, No. 2660601, JP-A Nos. 10-186356, 10-2020637, 10 A compound having a structure described in US Pat. No. -333134 can be used, but the present invention is not limited thereto.
[0046]
Examples of the liquid crystal compound other than the discotic liquid crystal compound and the polymer liquid crystal compound that can be used in the present invention generally include rod-shaped liquid crystal compounds, and a positive birefringent liquid crystal compound having an unsaturated ethylenic group is aligned. From the viewpoint of immobilization, compounds having structures described in JP-A Nos. 9-281480 and 9-281814 can be exemplified, but the invention is not particularly limited thereto.
[0047]
The structure of the liquid crystal compound in the present invention is not particularly limited, but the alignment of the liquid crystal compound is fixed by a chemical reaction or a temperature difference in a state where the liquid crystal molecules are aligned in order to develop optical anisotropy. It is required to be used in the state. An alignment film as described above can be placed on a transparent resin substrate, and a liquid crystal compound can be applied thereon for orientation. The alignment treatment of the liquid crystal compound requires heating to a temperature higher than the transition temperature of the liquid crystal compound, and the temperature is preferably not higher than the temperature at which the transparent resin substrate is not altered.
[0048]
When the liquid crystal compound used in the present invention is a polymer liquid crystal compound, the compound structure includes a main chain type liquid crystal polymer such as polyester, polyimide, polyamide, polyester, polycarbonate, and polyesterimide. Further, side chain type liquid crystalline polymer compounds such as polyacrylate, polymethacrylate, polysiloxane, polymalonate and the like may be used.
[0049]
As a method of applying the liquid crystal compound or alignment film, the liquid crystal compound or alignment film material is dissolved in an organic solvent, and then curtain coating, extrusion coating, roll coating, dip coating, spin coating, printing coating, spray coating and slide coating. However, the present invention is not limited to these.
[0050]
After applying the solution containing the liquid crystal compound of the present invention by the coating method as described above, a liquid crystal layer having a uniform film thickness can be obtained by removing the remaining solvent and the like in the drying step.
[0051]
The liquid crystal layer can fix the alignment of the liquid crystal compound by a chemical reaction by the action of heat and / or light energy. In particular, a monomeric liquid crystal compound generally has a low viscosity, and the alignment of the liquid crystal compound is easily affected by a thermal external factor. Therefore, a polymerizable liquid crystal compound is cured by a photoradical reaction using a photopolymerization initiator. Can also be fixed.
[0052]
In the present invention, in the case of fixing the alignment of the liquid crystal compound, when the polymerizable group is an ethylenically unsaturated group, a photopolymerization initiator is used. Can be shortened. In the above reaction system, it is preferable to use the light source described below as a means for generating radicals. For example, a high-pressure mercury lamp or a metal halide lamp that can strongly absorb near ultraviolet rays is preferable, and a maximum value of molar extinction coefficient with respect to light of 360 nm to 450 nm is preferably 100 or more, and more preferably 500 or more.
[0053]
In the inventions according to claims 5 and 10, it is one of the features that the curing reaction is further performed by irradiation of active rays to fix the alignment of the liquid crystal compound. As an actinic ray for photopolymerization, an electron beam, ultraviolet rays, visible rays, infrared rays (heat rays) and the like can be appropriately selected and used as necessary, but in general, ultraviolet rays are preferable. Examples of the ultraviolet light source include low-pressure mercury lamps (sterilization lamps, fluorescent chemical lamps, black lights), high-pressure discharge lamps (high-pressure mercury lamps, metal halide lamps), and short arc discharge lamps (ultra-high-pressure mercury lamps, xenon lamps, mercury xenon). Lamp).
[0054]
On the other hand, the radical polymerization initiator for the polymerization reaction of ethylenically unsaturated groups includes, for example, azobis compounds, peroxides, hydroperoxides, redox catalysts, such as potassium persulfate, ammonium persulfate, tert-butyl peroctoate. , Benzoyl peroxide, isopropyl percarbonate, 2,4-dichlorobenzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, dicumyl peroxide, azobisisobutyronitrile, 2,2'-azobis (2-amidino Propane) hydrochloride or benzophenones, acetophenones, benzoins, thioxanthones and the like. Details thereof are described in “Ultraviolet Curing System” General Technical Center, pages 63 to 147, 1989, and the like.
[0055]
For the polymerization of compounds having an epoxy group, for example, allyl diazonium salts (hexafluorophosphate, tetrafluoroborate, etc.), diallyl iodonium salts, group VIa allylonium salts (PF) can be used as UV-activated cationic catalysts.₆, AsF₆, SbF₆An allylsulfonium salt having an anion such as
[0056]
In addition, when performing a curing reaction using a radical reaction, in order to avoid a delay in the polymerization reaction due to the presence of oxygen in the air, irradiation with the active ray in a nitrogen atmosphere shortens the reaction time and reduces the amount of light. It is preferable in that it can be cured with
[0057]
In order to cure the liquid crystal compound using these reactions, it is important to select a monomer liquid crystal compound having a reactive group introduced also in the liquid crystal compound. The orientation of the liquid crystal compound can be fixed by this curing reaction.
[0058]
In the invention according to claim 7, after preparing an organic solvent solution containing a liquid crystal compound, applying and drying the solution, the temperature is set to a temperature equal to or higher than the glass transition temperature of the liquid crystal compound, and then the temperature is lowered to the glass transition temperature or lower to fix the alignment. It is the feature to become. When the liquid crystal compound is a polymer liquid crystal compound, the alignment of the liquid crystal compound may not be fixed by carrying out a curing reaction by the chemical reaction as described above. This is a temperature range in which the transparent resin substrate does not change due to heat, for example, when the polymer liquid crystal compound has a glass transition temperature of 90 ° C. or higher and exhibits a liquid crystal transition temperature, the polymer liquid crystal compound is applied onto the alignment film. After forming the constituent film, the liquid crystal compound is maintained in alignment by heating and orientation within the liquid crystal transition temperature range, and then allowing to cool at a temperature lower than the glass transition temperature, for example, room temperature.
[0059]
When the glass transition temperature of the polymer liquid crystal compound is higher than the heat resistance temperature of the support, an alignment film is provided on the heat resistant support according to the invention of claim 8, and the polymer liquid crystal compound is applied. After installation, the polymer liquid crystal compound can be heated and aligned at a glass transition temperature or higher. Then, the method of allowing the liquid crystal compound to cool to room temperature, fixing the orientation of the polymer liquid crystal compound, and then transferring it to the support of the present invention using an adhesive to produce an optical anisotropic body is also preferred in the present invention. This is one of the anisotropic body manufacturing methods.
[0060]
In the present invention, at least one optically anisotropic layer can be provided on the transparent support. Various types of liquid crystal display modes have been commercialized, and optically anisotropic bodies that can be optically compensated can design optical characteristics suitable for the display.
[0061]
The invention according to claim 11 is characterized in that the optically anisotropic layer is composed of a plurality of layers. In a case where a plurality of optical anisotropic layers are installed on one transparent support, the liquid crystal compound contained in the optical anisotropic layer is oriented or the orientation of the liquid crystal compound is fixed. The orientation direction can be appropriately set based on optical characteristics suitable for the display. When two or more optically anisotropic layers are provided on the transparent support, a plurality of alignment layers and optically anisotropic layers may be provided repeatedly in the order of distance from the transparent support. This is because the alignment film and the liquid crystal layer need to be adjacent because the alignment direction is determined by the alignment film. When these layers are installed in a plurality of layers, an alignment layer is directly coated on the liquid crystal layer coated on the alignment layer, or an intermediate layer composed of another known resin layer is disposed on the alignment layer. An alignment film can be applied and a liquid crystal layer can be provided on the plurality of alignment layers. When there are two liquid crystal layers, the alignment direction may be the same in the direction projected onto the transparent resin substrate surface, but preferably the crossing angle is 60 ° or more and 120 ° or less, more preferably the crossing angle is 85 °. The invention according to claim 12 is characterized by being substantially orthogonal at an angle of 95 ° or less, and this condition is preferable in that it is suitable for a specific display. On the other hand, the invention according to claim 13 is characterized in that the orientation angle is oblique when observed from the cross-sectional direction of the optical anisotropic layer, and the orientation angle is constant with respect to the thickness direction of the optical anisotropic layer. The orientation angle may change with respect to the thickness direction. The orientation angle varies depending on the design of the display for compensation, but is preferably 10 ° to 80 °, more preferably 15 ° to 60 °.
[0062]
In the present invention, when an optical anisotropic body is used as a protective film for a polarizing plate, or when an optical anisotropic body is attached to a polarizer with a protective film, the optical anisotropic body is installed between the liquid crystal cell and the polarizer. can do.
[0063]
A conventionally well-known thing can be used for a polarizer. For example, a film made of a hydrophilic polymer such as polyvinyl alcohol, which has been stretched by treatment with a dichroic dye such as iodine can be used.
[0064]
In the optically anisotropic support of the present invention, a plasticizer can be used for the purpose of improving physical properties. As a specific plasticizer, phosphoric acid ester or carboxylic acid ester is preferably used. Phosphoric esters include triphenyl phosphate (TPP) and tricresyl phosphate (TCP), biphenyl-diphenyl phosphate, dimethyl ethyl phosphate. Representative carboxylic acid esters include phthalic acid esters and citric acid esters. Examples of phthalic acid esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diethyl hexyl phthalate (DEHP), ethyl phthalyl ethyl glycolate and the like. As the citrate ester, acetyl triethyl citrate (OACTE) and acetyl tributyl citrate (OACTB) are used. Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Phosphate ester plasticizers (TPP, TCP, biphenyl-diphenyl phosphate, dimethylethyl phosphate) and phthalate ester plasticizers (DMP, DEP, DBP, DOP, DEHP) are preferably used.
[0065]
Of these, triphenyl phosphate (TPP) is particularly preferably used. The plasticizer is an important material for imparting water resistance to the transparent resin or improving its moisture permeability. However, if the amount added is too large, there is a problem that the adverse effect on the coating layer is enlarged. The invention according to claim 14 is characterized in that the addition amount of the plasticizer is 2 to 15% by mass in the transparent resin.
[0066]
By including an ultraviolet absorber in the transparent resin, an optical anisotropic body excellent in light resistance can be obtained, which is preferable. Examples of the ultraviolet absorber useful in the present invention include salicylic acid derivatives, benzophenone derivatives, benzotriazole derivatives, benzoic acid derivatives, and organometallic complex salts. Although not specifically limited as specific examples, for example, salicylic acid derivatives include phenyl salicylate, 4-t-butylphenyl salicylic acid and the like, and benzophenone derivatives include 2-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone and the like. Benzotriazole derivatives include 2- (2'-hydroxy-5'-methylphenyl) -benzotriazole, 2- (2'-hydroxy-3'-5'-di-butylphenyl) -5-chlorobenzo Triazole or the like, resorcinol-monobenzoate as benzoic acid derivative, 2 ', 4'-di-t-butylphenyl-3,5-t-butyl-4-hydroxybenzoate, etc., nickel as organic complex derivative Bis-octylphenylsulfamide, ethyl-3,5-di Can be mentioned nickel salts of t- butyl-4-hydroxybenzyl phosphoric acid, in the invention according to claim 15, it is characterized benzotriazole derivatives or benzophenone derivatives. In this invention, it is preferable to use 1 or more types of these ultraviolet absorbers, and you may contain 2 or more types of different ultraviolet absorbers. Moreover, you may use a polymeric ultraviolet absorber, for example, the compound illustrated by Unexamined-Japanese-Patent No. 6-148430. Preferred ultraviolet absorbers in the present invention are excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and have good liquid crystal display properties from the viewpoint of ultraviolet absorption shape and storage stability, or prevention of deterioration of the liquid crystal compound. Is preferably used that absorbs as little visible light as possible at a wavelength of 400 nm or longer. In particular, the transmittance at a wavelength of 370 nm needs to be 10% or less, preferably 5% or less, more preferably 2% or less.
[0067]
The UV absorber can be added by dissolving the UV absorber in an organic solvent such as alcohol, methylene chloride or dioxolane and then adding it to the dope for casting, or adding it directly into the dope composition for casting. Good. For an inorganic powder that does not dissolve in an organic solvent, a dissolver or a sand mill is used in the organic solvent and cellulose ester to disperse and then added to the dope.
[0068]
Next, a method for producing a cellulose ester film will be described.
First, a cellulose ester is dissolved in an organic solvent to form a dope. The concentration of the cellulose ester in the dope is about 10 to 35% by mass.
[0069]
Examples of the organic solvent include methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3. , 3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3 , 3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, non-chlorine organic solvents such as nitroethane are preferred. Of course, methylene chloride can also be used. Of these, methyl acetate and acetone can be preferably used. Use of a lower alcohol such as methanol, ethanol, or butanol is preferred because the solubility of cellulose ester in an organic solvent can be improved and the dope viscosity can be reduced. In particular, ethanol having a low boiling point and low toxicity is preferable.
[0070]
You may add additives, such as the said plasticizer, a ultraviolet absorber, and a mat agent, in dope. The obtained dope is cast on a rotating belt or drum support, dried until it becomes peelable, and peeled off from the support. The peeled raw dry film is further dried to evaporate the organic solvent in the film almost completely. The content of the organic solvent in the film is preferably 2% by mass or less, and more preferably 0.4% by mass or less in order to obtain good dimensional stability of the film.
[0071]
In manufacturing the film, it is useful in the present invention to use the following method.
[0072]
(1) In the process until the film is peeled off from the belt or drum, the amount of the residual solvent at the time of peeling is preferably 5% to 100%, more preferably 5% to 80%, still more preferably 10% to 45%.
[0073]
The amount of residual solvent in the film is represented by the following formula.
Residual solvent amount = residual volatile matter mass / film mass after heat treatment × 100%
The residual volatile matter mass is a value obtained by subtracting the film mass after the heat treatment from the film mass before the heat treatment when the film is heat treated at 115 ° C. for 1 hour.
[0074]
(2) The tension at the time of peeling and the preferable peeling tension at the time of conveying in the drying zone are 50 to 400 N / m, more preferably 100 to 300 N / m, and still more preferably 100 to 250 N / m. Moreover, as conveyance tension in a drying zone, Preferably it is 50-200 N / m, More preferably, it is 80-150 N / m, More preferably, it is 80-120 N / m.
[0075]
(3) In the drying process after peeling the film from the belt or drum, when the film is dried while being stretched by the pin tenter method or the clip tenter method, the retardation value (Rt value) increases and decreases as the stretching ratio increases. Decrease. A preferable stretching ratio is 2 to 50%, more preferably 5 to 40%, and still more preferably 10 to 30%.
[0076]
In addition, in order to improve the sliding property in the production process of the support of the present invention, particularly in the coating process, when producing a transparent resin film, during dope, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, carbonic acid It is preferable to contain inorganic fine particles such as calcium, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, and a matting agent such as a crosslinked polymer. Of these, silicon dioxide is preferable because it can reduce the haze of the film. The matting agent fine particles preferably have an average particle size of secondary particles of 0.01 to 1.0 μm and a content of 0.005 to 0.3 mass% with respect to the cellulose ester. For fine particles such as silicon dioxide, it is preferable that the surface of the particles is subjected to chemical processing because the haze of the film can be reduced. Preferred compounds for the surface treatment include, for example, halosilanes, alkoxysilanes, silazanes, siloxanes, and the like.
[0077]
The optical anisotropic body of the present invention often has a curl because it has a coating such as an optical anisotropic layer on the support. Therefore, it is preferable to provide an anti-curl layer on the opposite side to which the optically anisotropic layer is coated in order to prevent curling, eliminate the inconvenience due to curling, and prevent the function as an optical anisotropic body from being impaired. By appropriately imparting the property that the surface provided with the anti-curl layer shrinks inward, the degree of curl on the front and back surfaces can be balanced. The anti-curl layer is preferably applied also as a blocking layer, and in this case, the coating composition can contain inorganic fine particles and / or organic fine particles for imparting a blocking preventing function. Examples of the inorganic fine particles include silicon oxide, titanium oxide, aluminum oxide, tin oxide, zinc oxide, calcium carbonate, barium sulfate, talc, kaolin, calcium sulfate, and the like, and examples of the organic fine particles include polymethacrylic acid. Methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, silicone resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin resin powder, polyester resin powder Polyamide-based resin powder, polyimide-based resin powder, or polyfluorinated ethylene-based resin powder, and the like, and these additives can be added to the anti-curl layer coating composition. The fine particles such as silicon dioxide are preferably surface-treated with an organic substance because the haze of the film can be reduced. Preferred organic materials for the surface treatment include halosilanes, alkoxysilanes, silazanes, siloxanes, and the like.
[0078]
Examples of the fine particles of silicon dioxide include AEROSIL200, 200V, 300, R972, R974, R202, R812, OX50, TT600 manufactured by Nippon Aerosil Co., Ltd., preferably AEROSIL R972, R972V, R974, R974V, R202, R812. Etc.
[0079]
These fine particles are added in a range of 0.1 to 5 parts of particles having a volume average particle diameter of 0.005 to 0.1 μm with respect to 100 parts of the resin composition. These fine particles are preferably blended so that the haze of the film is 0.6% or less and the dynamic friction coefficient between the front and back surfaces of the optical anisotropic body is 0.5 or less.
[0080]
The imparting of the anti-curl function can also be performed by applying a composition containing a solvent that dissolves or swells the resin film substrate. As a solvent to be used, in addition to a solvent to be dissolved or a mixture of solvents to be swollen, there may be a solvent that is not further dissolved, and a composition in which these are mixed at a ratio appropriately selected according to the curl degree of the resin film and the type of resin is used. Apply. For example, when the anti-curl function is desired to be strengthened, it is effective to increase the mixing ratio of the solvent that dissolves the solvent composition to be used or the solvent that swells and to decrease the ratio of the solvent that does not dissolve. The mixing ratio at this time is preferably (solvent to be dissolved or solvent to be swollen) :( solvent not to be dissolved) = 10: 0 to 1: 9. Examples of the solvent for dissolving or swelling the resin film substrate contained in such a mixed composition include benzene, toluene, xylene, dioxane, acetone, methyl ethyl ketone, N, N-dimethylformamide, methyl acetate, ethyl acetate, and trichloroethylene. , Methylene chloride, ethylene chloride, tetrachloroethane, trichloroethane, chloroform and the like. Moreover, as a solvent which is not dissolved, methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butanol etc. can be mentioned, for example.
[0081]
These coating compositions are preferably applied to the surface of the resin film using a gravure coater, dip coater, reverse coater, extrusion coater or the like, with a wet film thickness of 1 to 100 μm, particularly preferably 5 to 30 μm.
[0082]
Examples of the resin used in the above-mentioned anti-curl layer, protective layer, intermediate layer, etc. include vinyl chloride / vinyl acetate copolymer, vinyl chloride resin, vinyl acetate resin, copolymer of vinyl acetate and vinyl alcohol, partial hydrolysis. Decomposed vinyl chloride / vinyl acetate copolymer, vinyl chloride / vinylidene chloride copolymer, vinyl chloride / acrylonitrile copolymer, ethylene / vinyl alcohol copolymer, chlorinated polyvinyl chloride, ethylene / vinyl chloride copolymer, Of vinyl polymers or copolymers such as ethylene / vinyl acetate copolymer, cellulose ester resins such as nitrocellulose, cellulose acetate propionate, diacetyl cellulose, cellulose acetate butyrate resin, maleic acid and / or acrylic acid Copolymer, acrylic ester copolymer , Acrylonitrile / styrene copolymer, chlorinated polyethylene, acrylonitrile / chlorinated polyethylene / styrene copolymer, methyl methacrylate / butadiene / styrene copolymer, acrylic resin, polyvinyl acetal resin, polyvinyl butyral resin, polyester polyurethane resin, polyether Examples include polyurethane resins, polycarbonate polyurethane resins, polyester resins, polyether resins, polyamide resins, amino resins, styrene / butadiene resins, rubber resins such as butadiene / acrylonitrile resins, silicone resins, and fluorine resins. It is not limited to these. Particularly preferred is a cellulose resin layer such as diacetylcellulose.
[0083]
The order of coating the anti-curl layer may be before or after coating the optically anisotropic layer on the opposite side of the resin film substrate. However, if the anti-curl layer also serves as an anti-blocking layer, the coating should be performed first. It is desirable to install.
[0084]
A protective layer may be provided on the liquid crystal layer of the optical anisotropic body of the present invention in order to avoid optical alteration such as scratches. In the case where the liquid crystal layer has a plurality of layers, an intermediate layer may be provided. Materials for the protective layer or intermediate layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, poly (N-methylolacrylamide), styrene / vinyltoluene copolymer, Nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, and polycarbonate, or polymers such as acrylate and methacrylate, and their derivatives Can be mentioned.
[0085]
When each constituent layer is installed on an optically anisotropic support, a coating solution in which constituent materials are dissolved using a solvent can be prepared and applied. This method is a preferable method from the viewpoint of the uniformity of the coating layer. The solvent to be used may be used alone, or two or more solvents may be mixed and used in order to control the drying property at the time of coating. The solvent for coating is preferably an organic solvent. Examples of alcohols include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2-butanol, tert-butanol, pentanol, 2-methyl-2-butanol, cyclohexanol and the like. Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and examples of esters include methyl formate, ethyl formate, methyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, ethyl lactate, Examples of glycol ethers (C1 to C4) include methyl cellosolve, ethyl cellosolve, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, propylene. As propylene glycol mono-n-propyl ether, propylene glycol monoisopropyl ether, propylene glycol monobutyl ether, or propylene glycol mono (C1-C4) alkyl ether esters, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, etc. Examples of the solvent include methylene chloride and N-methylpyrrolidone, but are not particularly limited thereto.
[0086]
【Example】
Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
[0087]

The above composition was put into a closed container, kept at 80 ° C. under pressure, and completely dissolved while stirring to obtain a dope composition. Next, this dope composition was used as Azumi Filter Paper No. The mixture was filtered using 244, then cooled, kept at 35 ° C., and evenly cast on a stainless steel band. After the solvent was evaporated until peeling was possible, the film was peeled off from the stainless steel band. In the drying zone between 50% by mass and 5% by mass of the residual solvent after peeling, the drying is advanced while maintaining the width by the tenter, and further, the residual solvent amount is 1% by mass or less while being conveyed by many rolls. It dried and produced the support bodies 1-4 with a film thickness of 110 micrometers.
[0088]
In addition, the cellulose acetate used for preparation of each support body is as follows.
Support 1: Cellulose acetate having a substitution degree of acetyl group of 2.92 (number average molecular weight 200000)
Support 2: Cellulose acetate having a substitution degree of acetyl group of 2.65 (number average molecular weight 170000)
Support 3: Cellulose acetate (number average molecular weight 200000) having an acetyl group substitution degree of 2.92 and cellulose acetate having a acetyl group substitution degree of 2.45 (number average molecular weight 100000) are mixed, and the average degree of acetyl group substitution after mixing is Adjustment was made to be 2.65.
[0089]
Support 4: Cellulose acetate having a degree of acetyl group substitution of 2.51 (number average molecular weight: 150,000) and cellulose acetate having a degree of acetyl group substitution of 2.86 (number average molecular weight: 180,000) are mixed, and the average degree of acetyl group substitution after mixing is Adjustment was made to be 2.65.
[0090]
<< Coating of alignment film, liquid crystal film and transfer layer >>
The following alignment films 1 and 2 and liquid crystal films 1 to 3 or transfer layer 1 were coated on the prepared supports 1 to 4 in the combinations shown in Table 1 to prepare optical anisotropic samples A to O. .
[0091]
[Table 1]

[0092]
(Coating of alignment film 1)
A 0.1 μm gelatin thin film was coated on each support shown in Table 1, and then linear alkyl-modified polyvinyl alcohol (MP203 Kuraray Co., Ltd.) was coated so that the dry film thickness was 0.2 μm. After drying this with 80 degreeC warm air, the rubbing process was performed and the alignment film 1 was formed.
[0093]
(Coating of alignment film 2)
On each support shown in Table 1, SANEVER 5291 (manufactured by Nissan Chemical Co., Ltd.) was applied so that the dry film thickness was 0.1 μm. This was dried at 110 ° C. for 3 hours and then rubbed to form an alignment film 2.
[0094]
(Coating of liquid crystal layer 1)
1.6 g of liquid crystalline discotic compound LC-1, 0.4 g of phenoxydiethylene glycol acrylate (M101 manufactured by Toa Gosei Co., Ltd.), cellulose acetate butyrate (CAB531-1 yeast) on the alignment film of each substrate configuration shown in Table 1. A coating solution obtained by dissolving 0.05 g of Man Chemical Co., Ltd. and 0.01 g of a photopolymerization initiator (Irgacure-907 Ciba Geigy Co., Ltd.) in 3.65 g of methyl ethyl ketone was applied with a wire bar. Next, this was affixed to a metal frame and fixed, and heated for 3 minutes in a thermostatic bath at 130 ° C. for drying and orientation to orient the discotic compound. Next, the illuminance is 10 mW / cm using a high-pressure mercury lamp in a nitrogen atmosphere.²Then, ultraviolet rays were irradiated at 130 ° C. for 30 seconds, and the orientation was fixed by a crosslinking reaction. After cooling to room temperature, the liquid crystal layer 1 containing a discotic compound was formed to prepare each optical anisotropic sample. The film thickness of the liquid crystal layer 1 was 1.8 μm.
[0095]
(Coating of liquid crystal layer 2)
A 10% by mass solution prepared by dissolving 5 g of LC-2 in 45 g of chloroform was applied on the alignment film of each substrate configuration shown in Table 1 by a printing method, dried on a hot plate at 110 ° C. After being heat-treated at 110 ° C. for 30 minutes for orientation, LC-2 was oriented and fixed by cooling to room temperature, and each optical anisotropic sample was prepared. The glass transition temperature of LC-2 is 90 ° C. The film thickness of the liquid crystal layer 2 was 2.0 μm.
[0096]
(Coating of liquid crystal layer 3)
1.6 g of LC-3, 0.4 g of phenoxydiethylene glycol acrylate (M101 manufactured by Toa Gosei Co., Ltd.), and a photopolymerization initiator (Irgacure-907 manufactured by Ciba-Geigy Co., Ltd.) were formed on the alignment films of the respective substrate configurations shown in Table 1. ) A coating solution obtained by dissolving 0.01 g in 3.65 g of methyl ethyl ketone was applied with a wire bar. Next, a metal frame was affixed to the metal frame, fixed and dried, and then subjected to a heat treatment for 3 minutes in a thermostatic bath at 120 ° C. to align the liquid crystal compound. Next, an illuminance of 10 mW / cm in a nitrogen atmosphere using a high-pressure mercury lamp²For 30 seconds, and then at 120 ° C. for 10 seconds, the alignment of the liquid crystal compound was fixed by a crosslinking reaction, and allowed to cool to room temperature to prepare each optical anisotropic sample. The film thickness of the liquid crystal layer 3 was 0.8 μm.
[0097]
[Chemical 1]

[0098]
(Coating of transfer layer 1)
On the heat-resistant polyimide film, SANEVER 5291 (manufactured by Nissan Chemical Co., Ltd.) was applied so that the dry film thickness was 0.1 μm. This was dried at 110 ° C. for 3 hours, and then rubbed to obtain an alignment film. Next, a liquid crystal layer composed of a 10 mass% solution in which 5 g of LC-4 was dissolved in 45 g of chloroform was applied on the alignment film. Next, it is dried on a hot plate at 80 ° C., subjected to heat treatment at 230 ° C. for 90 minutes for orientation in an oven, and then taken out to room temperature and cooled to fix LC-4 orientation on the polyimide film. did. In addition, the glass transition temperature of LC-4 used is 190 degreeC. Next, an ultraviolet curable adhesive was applied on the liquid crystal layer, then laminated on the supports 1 to 3 shown in Table 1, and the adhesive was cured by irradiation with light from a high-pressure mercury lamp, and then a polyimide film. Was removed. At this time, the liquid crystal layer is formed on the support via an adhesive. The adhesive layer was optically isotropic. The thickness of the liquid crystal layer was 1.9 μm.
[0099]
The optically anisotropic samples A to O produced as described above were immersed in a 2 mol / L sodium hydroxide aqueous solution at 60 ° C. for 2 minutes, washed with water, then dried at 100 ° C. for 10 minutes, and optically anisotropic alkalis Treated samples A to O were prepared.
[0100]
<Production of polarizing plate>
A 120 μm thick polyvinyl alcohol film was immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine and 4 parts by mass of boric acid, and stretched 4 times at 50 ° C. to prepare a polarizing film. On one side of the polarizing film, the support 1 having been subjected to the same alkali treatment as described above, and on the opposite side, the produced optical anisotropic alkali-treated samples A to O are liquid crystal with respect to the polarization axis. Adjust the panel viewing angle so that the viewing angle of the panel can be expanded, and bond the polarized light using a 5% aqueous solution of fully saponified polyvinyl alcohol as an adhesive so that the coated surface of the liquid crystal compound is located on the opposite side of the polarizing film. Plate samples A to O were prepared. Moreover, the comparison polarizing plate which bonded together the support body 1 which performed the alkali treatment on both surfaces of the polarizing film by the same method was also produced as a comparison polarizing plate.
[0101]
<< Characteristic evaluation of each sample >>
(Measurement of ΔN value of support)
About the produced said support bodies 1-4, the average refractive index of the whole film was first measured using the Abbe refractometer. Next, using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments), a three-dimensional refractive index measurement at a wavelength of 590 nm was performed in an environment of 23 ° C. and 55% RH. The average refractive index value measured with a rate meter was input, and the refractive indexes nx, ny, and nz were determined from the retardation angle characteristics. This three-dimensional refractive index is obtained from the retardation characteristics of the sample. Using the nx, ny, and nz measured as described above, the ΔN value of each support was calculated from Equation 1 above, and the obtained results are shown in Table 2.
[0102]
[Table 2]

[0103]
As is clear from the results in Table 2, the supports 2 to 4 of the present invention have a high value as the ΔN value defined by Formula 1, and are preferable characteristics from the viewpoint of thinning and weight reduction. I understand.
[0104]
(Evaluation of optical anisotropy)
The optical anisotropy of the optical anisotropic samples A to O was confirmed by the method shown below.
[0105]
As a result of observing the optical anisotropy of each optical anisotropic sample with a 100-fold optical microscope, the samples were all good, with the polarizing plate in a crossed Nicols state and each optical anisotropic sample placed between them. It has optical anisotropy and was confirmed to be monodomain.
[0106]
(Evaluation of viewing angle)
Polarized light obtained by peeling off the polarizing plate of the LA-1529HM type TFT-TN liquid crystal panel manufactured by NEC and peeling off each of the prepared polarizing plate samples A to O under the condition that the viewing angle is wider than that of the prepared comparative polarizing plate. It was attached to the liquid crystal panel in a direction that coincided with the polarization axis of the plate. Each polarizing plate sample was disposed between the polarizer and the liquid crystal panel, and was stuck so that the liquid crystal layer was outside the polarizing film. For attaching these polarizing plates, each sample was attached to each of the backlight side and the image observation surface side of the liquid crystal panel. For each of the liquid crystal panel samples A to O corresponding to the respective polarizing plate numbers prepared as described above, a monitor is driven by a personal computer, and the contrast ratio at the time of white / black display is set to Ez-Contrast manufactured by ELDIM. The angle from the normal direction of the liquid crystal panel showing a contrast of 10 or more was measured for each of up, down, left and right, and defined as the viewing angle. The results obtained by the above method are as follows.
[0107]
Compared with the liquid crystal panel sample A, the viewing angles of the liquid crystal panel samples D and G were enlarged.
In contrast to the liquid crystal panel sample B, the liquid crystal panel samples E and H have a larger viewing angle.
[0108]
In contrast to the liquid crystal panel sample C, the liquid crystal panel samples F and I have a wider viewing angle.
In contrast to the liquid crystal panel sample J, the viewing angle of the liquid crystal panel samples K and L was enlarged.
[0109]
Compared with the liquid crystal panel sample M, the liquid crystal panel samples N and O have a wider viewing angle.
From the above results, the liquid crystal panel sample using the support of the present invention having a high ΔN value compared to the comparative sample is excellent in that the viewing angle can be expanded when the thickness of the support is the same. I understand. This indicates that when the optical characteristics (viewing angle) equivalent to those of the comparative sample are obtained, the support of the present invention can easily design a thin film with respect to the comparative sample.
[0110]
(Measurement of retardation)
About each produced optically anisotropic sample, using the automatic birefringence meter KOBRA-21ADH (made by Oji Scientific Instruments), the angle (-40 degree- + 40 degree) in the slow axis of each optically anisotropic substance sample , The measurement was carried out every 10 °) and the retardation of the dependency was measured, and at the same time, the supports 1 to 4 were also measured. As a result of obtaining the retardation difference of each angular component of the corresponding support sample from the measured value of the optical anisotropic sample in which the liquid crystal layer exists, the optical anisotropic sample B, C, E, F, H, In I, K, L, N, and O, the angle indicating the maximum value of the retardation of the liquid crystal layer is deviated from the normal direction (0 °) with respect to the surface of the sample, and the liquid crystal compound molecules in the optically anisotropic layer are tilted. I found out. In addition, since the change in retardation with respect to the angle on the ± side with respect to the angle showing the maximum value is asymmetrical, the angle of the molecules of the liquid crystal compound changes in the thickness direction in all samples. Recognize.
[0111]
Next, for each of the optical anisotropic samples prepared as described above, an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments) was used to measure the angle (-40 ° to The range of + 40 °, the measurement was every 10 °), and the retardation of the dependency was measured. Similarly, the supports 1 to 4 were also measured. As a result of obtaining the retardation difference of each angular component of the corresponding support sample from the optical anisotropic sample in which the liquid crystal layer exists, the optical anisotropic samples A, D, G, and J It was found that the angle indicating the minimum value of the foundation was shifted from the normal direction (0 °) with respect to the surface of the sample, and the molecules of the liquid crystal compound in the optically anisotropic layer were tilted. In addition, since the change in the retardation of the ± side angle is asymmetric with respect to the angle indicating the minimum value, and the minimum value of the retardation is not 0, the liquid crystal compound molecules are thick in all samples. It can be seen that the angle changes with respect to the direction.
[0112]
Furthermore, optically anisotropic samples F ′ and I ′ in which the tilt angle of the liquid crystal compound is 0 ° are prepared by appropriately changing the rubbing conditions at the time of production for the optically anisotropic samples F and I, and incorporated. The polarizing plate samples F ′ and I ′ were prepared and evaluated in the same manner as described above. As a result, the polarizing plate samples F and I having an inclination angle in the orientation of the liquid crystal compound in the liquid crystal layer had an inclination angle of 0. Compared with the polarizing plate samples F ′ and I ′, the viewing angle was widened and good results were shown. From this, it was found that the polarizing plate of the present invention made of an optical anisotropic body having an inclination angle in the orientation of the liquid crystal compound is excellent.
[0113]
Example 2
In the optical anisotropic samples C, F, and I prepared in Example 1, a new alignment film 2 is installed on the outermost liquid crystal layer 3 at an angle orthogonal to the alignment layer 2 that has already been installed, and a rubbing treatment is performed. went. Further, a new liquid crystal layer 3 having the same composition as that of the already installed liquid crystal layer 3 is placed thereon, the orientation is fixed in the same manner, and polarizing plate samples C ″, F ″, I incorporating the same into the polarizing plate. ″ Was produced. As a result of evaluating the viewing angle using the produced polarizing plate in the same manner as in Example 1, the polarizing plate samples F ″ and I ″ had a wider viewing angle than the polarizing plate sample C ″. Was confirmed. As a result, even in an optical anisotropic body having a plurality of liquid crystal layers, it was found that the sample having the configuration according to the present invention has excellent viewing angle characteristics.
[0114]
Example 3
As a result of measuring the retardation value (Rt value) in the thickness direction of the support 2 of the present invention produced in Example 1 by the method shown below, the Rt value was 126.6 nm (thickness 110 μm). Next, for the support 1 as a comparative sample, the support thickness at the time of film formation was appropriately changed to produce a support 1 ′ having the same Rt value as the support 2. The obtained support 1 ′ had an Rt value: 126.5 nm and a thickness: 181 μm.
[0115]
<Measurement method of thickness direction retardation value (Rt value)>
Using an automatic birefringence meter KOBRA-21ADH, a three-dimensional refractive index measurement is performed at a wavelength of 590 nm in an environment of 23 ° C. and 55% RH to obtain refractive indices nx, ny, and nz. The foundation value (Rt value) was calculated.
[0116]
Rt value = ((nx + ny) / 2−nz) × d
In addition, nx, ny, and nz are synonymous with each of the said Formula 1 which calculates | requires (DELTA) N value. However, d represents the thickness (nm) of a film.
[0117]
From the above results, it can be seen that the support constituting the optical anisotropic body of the present invention is superior in that it can be made thinner than the comparative sample in order to obtain the desired optical characteristics (Rf value).
[0118]
Next, a polarizing plate 1 ′ was prepared using the support-1 ′ in the same manner as the polarizing plate sample F in Example 1, and the evaluation was performed according to the viewing angle evaluation method described in Example 1. The liquid crystal panel provided with 1 'expanded to almost the same viewing angle as the liquid crystal panel of the present invention provided with the polarizing plate F. However, the polarizing plate produced with the support 1 ′ is significantly different in thickness from the support 1 attached to the opposite side of the polarizing film, and therefore curls are not balanced on the front and back surfaces, causing curvature and ease of handling. It turned out that it is inferior to the polarizing plate of this invention by the point.
[0119]
Example 4
2- [5-Chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol (UV absorber) used in the supports 1 to 4 prepared in Example 1 1 kg) and 2- [2H-benzotriazol-2-yl] -4,6-di-tert-pentylphenol (1 kg), 2 kg of 2-hydroxy-4-benzyloxybenzophenone was added, and the support was similarly prepared. As a result of producing a liquid crystal panel by the same method as in Example 1 and evaluating the viewing angle, similarly to the result of Example 1, the sample of the present invention has a viewing angle performance with respect to the comparative sample. It was confirmed that it was excellent.
[0120]
【The invention's effect】
According to the present invention, an optical anisotropic body in which a liquid crystal layer is disposed on a support having advanced optical characteristics in which the difference in refractive index in the thickness direction is large with respect to the average refractive index in the support surface of the optical anisotropic body, and its A manufacturing method can be provided, and further, an optically anisotropic body that can be thinned and whose viewing angle can be enlarged, a manufacturing method thereof, a polarizing plate including the same, and a liquid crystal display device including the same can be provided. It was.

Claims (16)

An optical anisotropic body having an optical anisotropic layer on a transparent support, wherein the support is a cellulose ester resin having an acetyl group substitution degree of 2.55 or more and 2.70 or less. Cuboid. In an optical anisotropic body having an optical anisotropic layer on a transparent support, the support is a mixture of two or more cellulose ester resins having an acetyl group substitution degree of 2.40 or more and 3.00 or less. An optically anisotropic body, characterized in that it is a cellulose ester resin having an average degree of acetyl group substitution of from 2.55 to 2.70 . The optical anisotropic body according to claim 1, wherein the support includes a plasticizer and satisfies the following formula 1.
Formula 1
When defining ΔN value = (nx + ny) / 2−nz,
1.0 × 10 -3 ≦ ΔN ≦ 1.4 × 10 -3
[In the formula, nx represents the refractive index of the film in the casting direction, ny represents the refractive index of the film in the direction perpendicular to the casting direction (width direction), and nz represents the refractive index of the film in the thickness direction. ]   The optically anisotropic body according to any one of claims 1 to 3, wherein the optically anisotropic layer contains a polymerizable discotic liquid crystal compound.   In producing the optical anisotropic body according to claim 4, an organic solvent solution containing a polymerizable discotic liquid crystal compound is prepared, the solution is applied and dried, the temperature is adjusted for alignment, A method for producing an optical anisotropic body, wherein a curing reaction is carried out by irradiation to fix the orientation.   The optically anisotropic body according to any one of claims 1 to 3, wherein the optically anisotropic layer contains a polymer liquid crystal compound.   In producing the optical anisotropic body according to claim 6, after preparing an organic solvent solution containing a polymer liquid crystal compound, coating and drying the solution, the temperature for alignment is higher than the glass transition temperature of the liquid crystal compound. A method for producing an optical anisotropic body, characterized by adjusting and then lowering the temperature below the glass transition temperature to fix the orientation.   The optically anisotropic body according to any one of claims 1 to 3, wherein the optically anisotropic layer contains a low-molecular polymerizable liquid crystal compound having positive birefringence.   In producing the optical anisotropic body according to claim 8, an organic solvent solution containing a low-molecular polymerizable liquid crystal compound having positive birefringence is prepared, and the solution is applied and dried. For this purpose, a method for producing an optical anisotropic body is characterized in that the temperature is adjusted, and then a curing reaction is performed by irradiation with active rays to fix the orientation.   The optical anisotropic body according to claim 8, wherein the optical anisotropic layer comprises a plurality of layers.   The orientation based on the liquid crystal compound contained in the optically anisotropic layer is substantially uniform and the orientation angle is oblique with respect to the support surface. The optical anisotropic body described in the item.   The plasticizer is 2 or more and 15% by mass or less and the ultraviolet absorber is 0.01 or more and 3% by mass or less with respect to the resin constituting the support. The optical anisotropic body according to any one of 10 and 11.   The optical anisotropic body according to claim 12, wherein the ultraviolet absorber is a benzotriazole derivative or a benzophenone derivative.    The optical anisotropic body according to any one of claims 1 to 4, wherein the thickness of the support is 35 µm or more and 150 µm or less.   A polarizing plate protective film is the optical anisotropic body of any one of Claims 1-4, 6, 8, 10-14, The polarizing plate characterized by the above-mentioned.   A liquid crystal display device using the polarizing plate according to claim 15.