JP4069491B2 - Method for preparing cellulose acylate solution, method for producing cellulose acylate film, and cellulose acylate film - Google Patents

Description

【００６４】
一般式（Ｉ）、（II）、（III）の式中、Ｒは、それぞれ炭素原子数が１以上４以下のアルキル基である。上記一般式（Ｉ）、（II）又は（III）で示される化合物の例としては、リン酸２，２′−メチレンビス（４，６−ジ−ｔｅｒｔ−ブチルフェニル）ナトリウム（アデカスタブＮＡ−１０、旭電化（株）製）及びビス（ｐ−エチルベンジリデン）ソルビトール（ＮＣ−４、三井東圧化学（株）製）が含まれる。
【００６５】
酸化防止剤としては、下記一般式（IV）で表されるものが用いられる。
【００６６】
【化２】

【００６７】
一般式（IV）のＲ₁はアルキル基を表し、Ｒ₂、Ｒ₃及びＸは、それぞれ水素原子、アルキル基、アルケニル基、アリール基、ヘテロ環基、アルコキシ基、アルケノキシ基、アリールオキシ基、アルキルチオ基、アルケニルチオ基、アリールチオ基、ヘテロ環オキシ基、ヒドロキシ基、アミノ基、カルバモイル基、スルファモイル基、アルコキシカルボニル基、アリールオキシカルボニル基、ハロゲン原子、ニトロ基、シアノ基、アシル基、アシルオキシ基を表す。ｍは０〜２の整数を表す。Ｒ₂、Ｒ₃及びＸは互いに同一でもよいし異なっていてもよい。上記アルキル基は、例えば、メチル、エチル、プロピル、ｉｓｏ−プロピル、ｔｅｒｔ−ブチル、シクロヘキシル、ｔｅｒｔ−ヘキシル、ｔｅｒｔ−オクチル、ドデシル、ヘキサデシル、オクタデシル、ベンジルなどの直鎖、分岐、又は環状のアルキル基を表し、上記アルケニル基は、例えば、ビニル、アリル、２−ペンテニル、シクロヘキセニル、ヘキセニル、ドデセニル、オクタデセニルなどの直鎖、分岐、又は環状のアルケニル基を表し、上記アリール基は、例えば、フェニル、ナフチル、アントラニルなどのベンゼン単環や縮合多環のアリール基を表し、上記ヘテロ環基は、例えば、フリル、ピロリル、イミダゾリル、ピリジル、プリニル、クロマニル、ピロリジル、モルホリニルなどの窒素原子、硫黄原子、酸素原子の少なくとも一つを含む５〜７員環からなる基を表す。中でもヒンダードフェノール系の化合物が好ましく、２，６−ジ−ｔｅｒｔ−ブチル−ｐ−クレゾール、ペンタエリスリチル−テトラキス〔３−（３，５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシフェニル）プロピオネート〕、トリエチレングリコール−ビス〔３−（３−ｔｅｒｔ−ブチル−５−メチル−４−ヒドロキシフェニル）プロピオネート〕、１，６−ヘキサンジオール−ビス〔３−（３，５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシフェニル）プロピオネート〕、２，４−ビス−（ｎ−オクチルチオ）−６−（４−ヒドロキシ−３，５−ジ−ｔｅｒｔ−ブチルアニリノ）−１，３，５−トリアジン、２，２−チオ−ジエチレンビス〔３−（３，５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシフェニル）プロピオネート〕、オクタデシル−３−（３，５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシフェニル）プロピオネート、Ｎ，Ｎ’−ヘキサメチレンビス（３，５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシ−ヒドロシンナミド）、１，３，５−トリメチル−２，４，６−トリス（３，５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシベンジル）ベンゼン、トリス−（３，５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシベンジル）−イソシアヌレイトなどが挙げられる。特に２，６−ジ−ｔｅｒｔ−ブチル−ｐ−クレゾール、ペンタエリスリチル−テトラキス〔３−（３，５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシフェニル）プロピオネート〕、トリエチレングリコール−ビス〔３−（３−ｔｅｒｔ−ブチル−５−メチル−４−ヒドロキシフェニル）プロピオネート〕が最も好ましい。また例えば、Ｎ，Ｎ′−ビス〔３−（３，５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシフェニル）プロピオニル〕ヒドラジンなどのヒドラジン系の金属不活性剤やトリス（２，４−ジ−ｔｅｒｔ−ブチルフェニル）フォスファイトなどの燐系加工安定剤を併用してもよい。これらの化合物の添加量は、セルロースアシレートに対して重量割合で１ｐｐｍ〜１．０％が好ましく、１０〜１０００ｐｐｍが更に好ましい。
【００６８】
ライトパイピング防止用の着色剤としては下記一般式（Ｖ）、（VI）に示す化合物が挙げられる。
【００６９】
【化３】

【００７０】
一般式（Ｖ）、（VI）の式中、Ｘは酸素原子、又は、ＮＲ₂₃を表す。Ｒ₁〜Ｒ₈、Ｒ₁₂〜Ｒ₂₃は、それぞれ水素原子、水酸基、脂肪族基、芳香族基、複素環基、ハロゲン原子、シアノ基、ニトロ基、ＣＯＲ₉、ＣＯＯＲ₉、ＮＲ₉Ｒ₁₀、ＮＲ₁₀ＣＯＲ₁₁、ＮＲ₁₀ＳＯ₂Ｒ₁₁、ＣＯＮＲ₉Ｒ₁₀、ＳＯ₂ＮＲ₉Ｒ₁₀、ＣＯＲ₁₁、ＳＯ₂Ｒ₁₁、ＯＣＯＲ₁₁、ＮＲ₉ＣＯＮＲ₁₀Ｒ₁₁、ＣＯＮＨＳＯ₂Ｒ₁₁、又はＳＯ₂ＮＨＣＯＲ₁₁を表し、Ｒ₉、Ｒ₁₀はそれぞれ水素原子、脂肪族基、芳香族基、複素環基を表し、Ｒ₁₁は脂肪族基、芳香族基、又は複素環基を表す。
【００７１】
Ｒ₁〜Ｒ₂₃で表される脂肪族基は、炭素数１〜２０のアルキル基（例えば、メチル、エチル、ｎ−ブチル、イソプロピル、２−エチルヘキシル、ｎ−デシル、ｎ−オクタデシル）、炭素数１〜２０のシクロアルキル基（例えば、シクロベンジル、シクロヘキシル）又はアリル基を表し、これらは更に置換基（例えば、ハロゲン原子、水酸基、シアノ基、ニトロ基、カルボン酸基、炭素数６〜１０のアリール基、炭素数０〜２０のアミノ基、炭素数１〜２０のアミド基、炭素数１〜２０のカルバモイル基、炭素数２〜２０のエステル基、炭素数１〜２０のアルコキシ基又はアリーロキシ基、炭素数１〜２０のスルホンアミド基、炭素数０〜２０のスルファモイル基、５又は６員の複素環を有していてもよい。Ｒ₁〜Ｒ₂₃で表される芳香族基は炭素数６〜１０のフェニル、ナフチルなどのアリール基を表し、前記に挙げた置換基及び炭素数１〜２０のメチル、エチル、ｎ−ブチル、ｔｅｒｔ−ブチル、オクチルなどのアルキル基からなる置換基を有していてもよい。Ｒ₁〜Ｒ₁₁で表される複素環基は、５又は６員の複素環を表し、前記の置換基を有していてもよい。以下化４〜化９に一般式（Ｖ）、（VI）で表される化合物の好ましい例（Ｖ−１）〜（Ｖ−２５）、及び（VI−１）〜（VI−４）を示す。
【００７２】
【化４】

【００７３】
【化５】

【００７４】
【化６】

【００７５】
【化７】

【００７６】
【化８】

【００７７】
【化９】

【００７８】
着色剤の含有量は、セルロースアシレートに対する重量割合で１０〜１０００ｐｐｍが好ましく、５０〜５００ｐｐｍが更に好ましい。この様に着色剤を含有させることにより、セルロースアシレートフィルムのライトパイピングが減少でき、黄色味を改良することができる。これらの化合物は、セルロースアシレート溶液の調製の際に、セルロースアシレートや溶媒と共に添加してもよいし、溶液調製中や調製後に添加してもよい。
【００７９】
また、本発明のセルロースアシレート溶液には、必要に応じて更に種々の添加剤を溶液の調製前から調製後のいずれの段階で添加してもよい。添加剤としては、紫外線吸収剤、カオリン、タルク、ケイソウ土、石英、炭酸カルシウム、硫酸バリウム、酸化チタン、アルミナなどの無機微粒子、カルシウム、マグネシウムなどのアルカリ土類金属の塩などの熱安定剤、帯電防止剤、難燃剤、滑剤、油剤などである。
【００８０】
溶液は流延に先だって金網やネルなどの適当な濾材を用いて、未溶解物やゴミ、不純物などの異物を濾過除去しておくのが好ましい。
【００８１】
本発明のセルロースアシレート溶液を用いたフィルムの製造方法について述べる。本発明のセルロースアシレートフィルムを製造する方法及び設備は、従来セルローストリアセテートフィルム製造に供する溶液流延製膜方法及び溶液流延製膜装置が用いられる。図８は溶液流延製膜装置の断面模式図であり、これを用いて溶液流延製膜方法及び装置について簡単に説明する。前述の溶解機（釜）から調製されたドープ（セルロースアシレート溶液）を貯蔵釜７７で一旦貯蔵し、ドープに含まれている泡を脱泡したり最終調製をする。ドープ７８をドープ排出口８１から、例えば回転数によって高精度に定量送液できる加圧型定量ギヤポンプ８２を通して加圧型ダイ７２に送り、ドープを加圧型ダイ７２の口金（スリット）からエンドレスに走行している流延部の支持体７１の上に均一に流延され、支持体がほぼ一周した剥離点７４で、生乾きのドープ膜（ウェブとも呼ぶ）を支持体７１から剥離し、ウェブ７３の両端をクリップで挟み幅保持しながらテンター７５で搬送して乾燥し、続いて乾燥装置８４のロール群８５で搬送し乾燥を終了して巻き取り機７６で所定の長さに巻き取る。なお、７９はドープ導入口、８０は添加剤導入口、８３は保温ジャケットである。テンターとロール群の乾燥装置との組み合わせはその目的により変わる。ハロゲン化銀写真感光材料に用いる溶液流延製膜方法においては、図８の溶液流延製膜装置に記載されている装置の他に、下引層、帯電防止層、ハレーション防止層、保護層等の支持体への表面加工のために、塗布装置が付加されることが多い。
【００８２】
本発明に有用な流延方法としては、調製されたドープを加圧ダイから支持体上に均一に押し出す方法、一旦支持体上に流延されたドープをブレードで膜厚を調節するドクターブレードによる方法、或いは逆回転するロールで調節するリバースロールコーターによる方法等があるが、加圧ダイによる方法が好ましい。加圧ダイにはコートハンガータイプやＴダイタイプ等があるがいずれも好ましく用いることができる。また、ここで挙げた方法以外にも従来知られているセルローストリアセテート溶液を流延製膜する種々の方法（例えば特開昭６１−９４７２４号、同６１−１４８０１３号、特開平４−８５０１１号、同４−２８６６１１号、同５−１８５４４３号、同５−１８５４４５号、同６−２７８１４９号、同８−２０７２１０号公報などに記載の方法）を好ましく用いることが出来、用いる溶媒の沸点等の違いを考慮して各条件を設定することによりそれぞれの公報に記載の内容と同様の効果が得られる。
【００８３】
本発明のセルロースアシレートフィルムを製造するのに使用されるエンドレスに走行する支持体としては、表面がクロムメッキによって鏡面仕上げされたドラムや表面研磨によって鏡面仕上げされたステンレスベルト（バンドといってもよい）が用いられる。
【００８４】
本発明のセルロースアシレートフィルムの製造に用いられる加圧ダイは、支持体の上方に１基或いは２基以上の設置でもよい。好ましくは１基又は２基である。２基以上設置する場合には流延するドープ量をそれぞれのダイに種々な割合にわけてもよく、複数の精密定量ギヤアポンプからそれぞれの割合でダイにドープを送液する。
【００８５】
本発明のセルロースアシレートフィルムの製造に係わる支持体上におけるドープの乾燥は、一般的には支持体（ドラム或いはベルト）の表面側、つまり支持体上にあるウェブの表面から熱風を当てる方法、ドラム或いはベルトの裏面から熱風を当てる方法、温度コントロールした液体をベルトやドラムのドープ流延面の反対側の裏面から接触させて、伝熱によりドラム或いはベルトを加熱し表面温度をコントロールする液体伝熱方法などがあるが、裏面液体伝熱方式が好ましい。
【００８６】
流延される前の支持体の表面温度はドープに用いられている溶媒の沸点以下であれば何度でもよい。しかし乾燥を促進するためには、また支持体上での流動性を失わせるためには、使用される溶媒の内の最も沸点の低い溶媒の沸点より１〜１０℃低い温度に設定することが好ましい。
【００８７】
セルロースアシレートフィルムを製造する速度はベルトの長さ、乾燥方法、ドープ溶媒組成等によっても変化するが、ウェブをベルトから剥離する時点での残留溶媒の量によって殆ど決まってしまう。つまり、ドープ膜の厚み方向でのベルト表面付近での溶媒濃度が高すぎる場合には、剥離した時、ベルトにドープが残ってしまい、次の流延に支障を来すため、剥離残りは絶対あってはならないし、更に剥離する力に耐えるだけのウェブ強度が必要であるからである。剥離時点での残留溶媒量は、ベルトやドラム上での乾燥方法によっても異なり、ドープ表面から風を当てて乾燥する方法よりは、ベルト或いはドラム裏面から伝熱する方法が効果的に残留溶媒量を低減することが出来るのである。
【００８８】
本発明のセルロースアシレートフィルムの製造に係わるフィルム乾燥方法については前述の溶液流延製膜方法の乾燥方法が好ましい。搬送中のウェブ（フィルム）両面に所定の温度の風を当てる方法やマイクロウェーブなどの加熱手段などを用いる方法によって乾燥が行われる。急速な乾燥はウェブ（フィルム）の平面性を損なう恐れがあるので、乾燥の初期段階では、溶媒が発泡しない程度の温度で乾燥し、乾燥が進んでから高温で乾燥を行うのが好ましい。
【００８９】
支持体から剥離後の乾燥工程では、溶媒の蒸発によってフィルムは巾方向に収縮しようとする。高温度で乾燥するほど収縮が大きくなる。この収縮は可能な限り抑制しながら乾燥することが、出来上がったフィルムの平面性を良好にする上で好ましい。この点から、例えば、特開昭６２−４６６２５号公報に示されているような乾燥全工程或いは一部の工程を幅方向にクリップでウェブの巾両端を巾保持しつつ乾燥させる方法（テンター方式）が好ましい。
【００９０】
更には、積極的に幅方向に延伸する方法もあり、本発明では、例えば、特開昭６２−１１５０３５号、特開平４−１５２１２５号、同４−２８４２１１号、同４−２９８３１０号等の公報に記載の延伸方法も使用し得る。
【００９１】
本発明のセルロースアシレートフィルムの乾燥工程における乾燥温度は４０〜２５０℃、特に７０〜１８０℃が好ましい。使用する溶媒によって乾燥温度、乾燥風量及び乾燥時間が異なり、使用溶媒の種類、組合せに応じて適宜選べばよい。最終仕上がりフィルムの残留溶媒量は２重量％以下、更に０．４重量％以下であることが、寸度安定性が良好なフィルムを得る上で好ましい。
【００９２】
これら流延から後乾燥までの工程は、空気雰囲気下でもよいし窒素ガスなどの不活性ガス雰囲気下でもよい。
【００９３】
本発明のセルロースアシレートフィルムの製造に係わる巻き取り機は一般的に使用されているものでよく、定テンション法、定トルク法、テーパーテンション法、内部応力一定のプログラムテンションコントロール法などの巻き取り方法で巻き取ることができる。
【００９４】
本発明の出来上がり（乾燥後）のセルロースアシレートフィルムの厚さは、使用目的によって異なるが、通常５から５００μｍの範囲であり、更に４０〜２５０μｍの範囲が好ましく、特に６０〜１２５μｍの範囲が最も好ましい。フィルム厚さの調製は、所望の厚さになるように、ドープ中に含まれる固形分濃度、ダイの口金のスリット間隙、ダイからの押し出し圧力、支持体速度等を調節すればよい。
【００９５】
〈アシル基の置換度と粘度平均重合度の測定方法〉
１）セルロースアシレートのアシル基の置換度；
アシル基の置換度は、ケン化法によって測定するものとする。乾燥したセルロースアシレートを精秤し、アセトン７０ｍｌとジメチルスルホキシド３０ｍｌとの混合溶媒に溶解した後、更にアセトン５０ｍｌを加えた。攪拌しながら１Ｎの水酸化ナトリウム水溶液３０ｍｌを加え、２５℃で２時間ケン化する。熱水１００ｍｌを加え、フェノールフタレインを指示薬として添加し、１Ｎの硫酸水溶液（濃度ファクター；Ｆ）で過剰の水酸化ナトリウムを滴定する。また、上記と同様な方法により、ブランクテストを行う。滴定が終了した溶液の上澄み液を１００に希釈し、イオンクロマトグラフィーを用いて、定法により有機酸の組成を測定した。滴定結果とイオンクロマトグラフィーの酸組成物分析から下記によりアシル化置換度を計算した。
【００９６】
Ｔ［Ａ＋Ｂ］＝（Ｅ−Ｍ）×Ｆ／（１０００×Ｗ）
Ａ＝｛１６２．１４×Ｔ［Ａ＋Ｂ］｝／｛１−４２．１４×Ｔ［Ａ＋Ｂ］＋（１−５６．０６×Ｔ［Ａ＋Ｂ］）×（Ｃｂ／Ｃａ）｝
Ｂ＝Ａ×（Ｃｂ／Ｃａ）
ここで、
Ｔ［Ａ＋Ｂ］：全有機酸量（モル／ｇ）
Ｅ：ブランク試験滴定量（ｍｌ）
Ｍ：試料滴定量（ｍｌ）
Ｆ：１Ｎの硫酸のファクター
Ｗ：試料重量（ｇ）
Ｃａ：イオンクロマトグラフィーで測定した酢酸量（モル）
Ｃｂ：イオンクロマトグラフィーで測定した炭素原子数３乃至５の有機酸量（モル）
Ｃｂ／Ｃａ：酢酸と他の有機酸とのモル比
Ａ：アセチル基の置換度
Ｂ：炭素原子数３乃至５のアシル基の置換度
である。
【００９７】
２）セルロースアシレートの粘度平均重合度（ＤＰ）
絶乾したセルロースアシレート約０．２ｇを精秤し、メチレンクロライドとエタノールの混合溶媒（重量比９：１）１００ｍｌに溶解する。これをオストワルド粘度計にて、２５℃で落下秒数を測定し、重合度を以下の式によって求める。
【００９８】
ηｒｅｌ＝Ｔ／Ｔｓ
［η］＝（ｌｎηｒｅｌ）／Ｃ
ＤＰ＝［η］／Ｋｍ
ここで、
Ｔ ：測定試料の落下秒数
Ｔｓ：溶媒の落下秒数
Ｃ ：濃度（ｇ／ｌ）
Ｋｍ：６×１０^-4
【００９９】
【実施例】
以下、実施例を挙げて本発明を詳細に説明するが、本発明の態様はこれに限定されるものではない。
【０１００】
フィルムの残留溶媒量は次のように測定した。
【０１０１】
試験フィルム或いはウェブ（Ｕ）を秤量ビンに入れ精秤し、次に前記フィルム或いはウェブを１５０℃で３時間加熱した後、水分を吸わないように室温まで冷却し秤量する。絶乾フィルム或いはウェブの重量（Ｄ）として、
残留溶媒量（％）＝｛（Ｕ−Ｄ）／Ｄ｝×１００
で求めた。
【０１０２】
実施例中のドープについては透明性と経時安定性、それにドープの粘度を、またフィルムについては、ヘイズ、引裂強度、引張強度、弾性率及び耐折度を、各測定及び評価方法は以下の方法で行った。なお、ここでフィルムとはセルロースアシレートフィルム製造工程の最終段階の巻き取り工程で巻き取り後切り出した乾燥されたフィルムをいう。
【０１０３】
〈ドープの透明性及び経時安定性〉
ドープ（セルロースアシレート溶液）を透明な容器に入れ、目視で作製直後、７２時間後及び１６８時間後の透明性を観察し、同時に容器を逆さまにして溶液の流動性の変化を観察し、次の基準で評価しランク付けした。
【０１０４】
Ａ：透明で均一なドープで、容器を逆さにするとスムーズにドープが移動した
Ｂ：僅かに濁りはあるが、透明性はある。容器を逆さまにすると流動性はあるが、移動する界面に若干つぶつぶ状のものが認められる
Ｃ：濁りがあり、不溶解物が認められ、容器を逆さまにするとドープは不均一に移動する
Ｄ：著しく濁り、不溶解物が多く、相分離しており、又は、容器を逆さまにしても流動性がなくゲル状になっている。
【０１０５】
〈ヘイズ〉
ＪＩＳ Ｋ−６７１４に従って、ヘイズメーター（１００１ＤＰ型、日本電色工業（株）製）を用いて測定した。
【０１０６】
〈引裂強度〉
フィルムを温度２３℃、相対湿度５５％ＲＨに調湿された部屋で４時間調湿した後、試料寸法５０ｍｍ×６４ｍｍに切り出し、ＩＳＯ ６３８３／２−１９８３に従い測定して求めた。
【０１０７】
〈引張強度と弾性率〉
フィルムを温度２３℃、相対湿度５５％ＲＨに調湿された部屋で４時間調湿した後、試料巾１０ｍｍ、長さ２００ｍｍに切断し、チャック間距離１００ｍｍにして引っ張り速度１００ｍｍ／分で引っ張り試験を行い求めた。
【０１０８】
〈耐折度〉
フィルムを温度２３℃、相対湿度５５％ＲＨに調湿された部屋で４時間調湿した後、試料長さ１２０ｍｍに切り出し、ＩＳＯ ８７７６／２−１９８８に従い、折り曲げによって切断するまでの折り曲げ回数を測定した。
【０１０９】
実施例１
図１に示したような混合釜を用いて、３０℃のアセチル基の置換度２．９０、粘度平均重合度３００のセルローストリアセテート１００重量部を、予め混合釜に−８０℃に冷却しておいた酢酸メチルとアセトンからなる混合有機溶媒（混合重量比７：３）５００重量部中に撹拌しながら徐々に投入した。投入が終了してから２０分後セルローストリアセテートは全て膨潤し、得られた膨潤した混合物を溶解釜に移送した。溶解釜中の膨潤した混合物を５０℃に加温しセルローストリアセテートの濃度が２０重量％になるように調製した。更にトリフェニルフォスフェート１０重量部を添加した。４０分間撹拌を続けたところ、膨潤した混合物は溶解し透明なドープを得た。ドープを３０℃で一晩静置し、脱泡操作を施した後、ドープを安積濾紙（株）製の安積濾紙Ｎｏ．２４４を使用して濾過し製膜に供した。得られたドープを定量ギヤポンプでダイに送液し、エンドレスに走行しているステンレスベルトに、乾燥後の膜厚が１２０μｍとなるように、流延した。裏面から５０℃の温水を接触させて温度制御されたベルト上で前半の乾燥を行い、後半は９０℃の乾燥風を当ててウェブを乾燥した。ベルトが１周するところでベルトからウェブを剥離し、ウェブの両端をクリップで把持しながら１２０℃で５分間、続いてロールで搬送しながら１４０℃で２０分間乾燥し最終的に膜厚１２０μｍのセルローストリアセテートフィルムを得た。フィルムの残留溶媒量は０．８％であった。
【０１１０】
実施例２
図２に示したような目開き５ｍｍのステンレス製のメッシュ付きの混合釜を用いて、３０℃のアセチル基の置換度２．７１、プロピオニル基の置換度０．１７、粘度平均重合度３５０のセルロースアセテートプロピオネート１００重量部を、予め混合釜に−７０℃に冷却しておいた酢酸メチルとアセトンからなる混合有機溶媒（混合重量比７：３）９００重量部中に撹拌しながら徐々に投入した。投入が終了してから２０分後、セルロースアセテートプロピオネートは全て膨潤した。膨潤に関与しなかった有機溶媒をメッシュを通して排出し、膨潤した混合物を溶解釜に移送した。溶解釜を５０℃に加温し、更に５０℃に加温した酢酸メチルとアセトンの混合有機溶媒（重量比７：３）を加え、セルロースアセテートプロピオネートの濃度が２０重量％になるように調製した。更にトリフェニルフォスフェート１０重量部を添加した。２０分間撹拌を続けたところ、膨潤した混合物は溶解し透明なドープとなった。ドープを３０℃で一晩静置し、脱泡操作を施した後、ドープを安積濾紙（株）製の安積濾紙Ｎｏ．２４４を使用して濾過し製膜に供した。実施例１と同様にして製膜し、１２０μｍのセルロースアセテートプロピオネートフィルムを得た。フィルムの残留溶媒量は０．９％であった。
【０１１１】
実施例３
図２の混合釜と図３の溶解釜を用いて試験した。図２に示したような目開き５ｍｍのステンレス製のメッシュ付きの混合釜を用いて、３０℃のアセチル基の置換度２．７１、プロピオニル基の置換度０．１７、粘度平均重合度３５０のセルロースアセテートプロピオネート１００重量部を、予め混合釜に−７０℃に冷却しておいた酢酸メチルとアセトンからなる混合有機溶媒（混合重量比７：３）１０００重量部中に撹拌しながら徐々に投入した。投入が終了してから２０分後、セルロースアセテートプロピオネートは全て膨潤した。膨潤に関与しなかった有機溶媒をメッシュを通して６００重量部排出し、得られた膨潤した混合物を溶解釜に移送した。図３の溶解釜に予め５０℃に加温しておいた同様の有機溶媒２００重量部に膨潤した混合物を投入し、温度を５０℃に保ち、撹拌しながら溶解させた。２０分もしないうちに完全に溶解した。調製したドープを用いて、実施例１と同様に溶液流延製膜方法で１２０μｍのセルロースアセテートプロピオネートフィルムを得た。残留溶媒量は０．９％であった。
【０１１２】
実施例４
図４と図５の連続混合機、有機溶媒分離器を用いて試験した。図４に示すように、３０℃のアセチル基の置換度２．７１、プロピオニル基の置換度０．１７、粘度平均重合度３５０のセルロースアセテートプロピオネートを、予め−７０℃に冷却した移送中の酢酸メチルとアセトンからなる混合有機溶媒（重量比７：３）に次々と投入した。投入の速度は混合溶媒の単位時間当たりの流量に対して５重量％になるように調整した。投入してから５分後には混合機の終点ではセルロースアセテートプロピオネートは全て膨潤した。投入は１０粉で終了した。従って膨潤時間としては１５分を要した。次に膨潤した混合物を、目開き１ｍｍのステンレス製のメッシュを備えた有機溶媒分離器に導入し、膨潤に関与しなかった過剰の有機溶媒を分離しながら移送中の混合物を濃縮し、濃縮された混合物を溶解釜に移送した。分離した有機溶媒は使用した量の６０重量％を回収した。溶解釜には予め５０℃に加温しておいた前記と同組成の有機溶媒に、濃縮された混合物を連続的に投入した。濃縮された混合物は５０℃の有機溶媒に触れるとすぐに溶解し透明なドープとなった。全ての濃縮された混合物を投入終了し終わるのに１０分を要した。このドープを用い、実施例１と同様に溶液流延製膜方法で１２０μｍのセルロースアセテートプロピオネートフィルムを得た。残留溶媒量は０．９％であった。
【０１１３】
実施例５
図６に示した連続混合機、連続有機溶媒分離器及び連続溶解機を用いて試験した。３０℃のアセチル基の置換度２．７１、プロピオニル基の置換度０．１７、粘度平均重合度３５０のセルロースアセテートプロピオネートを、予め−７０℃に冷却した移送中の酢酸メチルとアセトンからなる混合有機溶媒（重量比７：３）に次々に投入した。投入の速度は混合溶媒の単位時間当たりの流量に対して５重量％になるように調整した。投入してから５分後には混合機の終点ではセルロースアセテートプロピオネートは全て膨潤した。投入は１０分で終了した。従って膨潤時間としては１５分を要した。次に膨潤した混合物を、目開き１ｍｍのステンレス製のメッシュを備えた分離器に導入し、膨潤に関与しなかった過剰の有機溶媒を分離しながら移送中の混合物を濃縮し溶解工程に移送した。濃縮された混合物に対するセルロースアセテートプロピオネートの濃度は４０重量％になっていた。溶解機には、予め５０℃に加温しておいた酢酸メチルとアセトンの混合有機溶媒（重量比７：３）が流れており、その中に該濃縮された混合物を投入した。溶解機への濃縮された混合物の加温有機溶媒への投入比は１：１とした。濃縮された混合物は投入してすぐに溶解が始まり、２０重量％のセルロースアセテートプロピオネート溶液（ドープ）を得、貯蔵釜に導入した。全ての濃縮された混合物を投入し終わるのに１０分を要した。ここでトリフェニルホスフェートをセルロースアシレートに対して１０重量％になるように若干の有機溶媒（同比率の）を貯蔵釜に投入して撹拌しながら溶解させた。このドープを用い、実施例１と同様に溶液流延製膜方法で製膜を行い、１２０μｍのセルロースアセテートプロピオネートフィルムを得た。フィルムの残留溶媒量は０．９％であった。
【０１１４】
実施例６
有機溶媒を酢酸メチルとエタノール（９５：５）に変更した以外は実施例２と同様にして、１２０μｍのセルロースアセテートプロピオネートフィルムを得た。残留溶媒量は１．０％であった。
【０１１５】
実施例７
アセチル基の置換度２．８８、粘度平均重合度３００のセルローストリアセテートを用いた以外は実施例５と同様に溶解を行い、溶液流延製膜方法で製膜し、１２０μｍのセルローストリアセテートフィルムを得た。残留溶媒量は１．１％であった。
【０１１６】
実施例８
アセチル基の置換度２．６１、プロピオニル基の置換度０．３、粘度平均重合度４００のセルロースアセテートプロピオネートに変更した以外は実施例１と同様にドープを得た。また溶液流延製膜方法で１２０μｍのセルロースアセテートプロピオネートフィルムを得た。残留溶媒量は１．２％であった。
【０１１７】
実施例９
アセチル基の置換度２．３８、プロピオニル基の置換度０．３９、粘度平均重合度４５０のセルロースアセテートプロピオネートに変更した以外は実施例３と同様にドープを得た。溶液流延製膜方法で１２０μｍのセルロースアセテートプロピオネートフィルムを得た。
【０１１８】
実施例１０
実施例５において、分離された有機溶媒を有機溶媒分離器の有機溶媒排出口から排出させ、ポンプでフィルターに送り、安積濾紙（株）製の安積濾紙Ｎｏ．２４４を１０枚用いて濾過して冷却器で再び冷却して再使用有機溶媒を、新鮮な有機溶媒と１：１で混合して使用し、２４時間連続的に溶解を行いドープを得た。
【０１１９】
比較例１
アセチル基の置換度２．８８、粘度平均重合度３００のセルローストリアセテート１００重量部、酢酸メチル５００重量部、及びトリフェニルホスフェート１０重量部を室温で混合し、次に撹拌しながら混合釜のジャケットに−７０℃の冷媒を導入して３０分間冷却し、ジャケットの冷媒を除き、５０℃の温水をジャケットに導入し、３０分その温度を保持し、温水を除き混合物の溶解状態を観察したところ、溶解が不十分であったため、もう１度繰り返し処理を行いドープを調製した。従ってセルローストリアセテートが溶解するまでに少なくとも１２０分を要した。実施例１と同様にドープの泡を除き、溶液流延製膜方法により１２０μｍのセルローストリアセテートフィルムを得た。残留溶媒量は０．９％であった。
【０１２０】
比較例２
有機溶媒をアセトン４００重量部及びアセチル基の置換度２．５６、プロピオニル基の置換度０．３５に変更した以外は比較例１と同様に１２０μｍのセルロースアセテートプロピオネートフィルムを得た。残留溶媒量は１．１％であった。
【０１２１】
以上の試験を行い、評価結果を表１に示した。
【０１２２】
【表１】

【０１２３】
（結果）表１から明らかなように、本発明の溶解方法は、比較例１及び２に示す従来の冷却溶解方法と比較して、大幅に溶解時間を短縮することが出来た。また、得られたドープの透明性及び経時安定性も良好で、更に得られたセルロースアシレートフィルムはヘイズ、機械的強さも強く良好であり、ハロゲン化銀写真感光材料や液晶画像表示装置用に十分使用する目処がたった。
【０１２４】
また、表には示していないが、実施例１０の混合物から分離された有機溶媒を２４時間に亘り溶解に使用し続けた結果、ドープの透明性には全く問題ないことがわかった。
【０１２５】
【発明の効果】
塩素系有機溶媒の使用量の大幅削減或いは、全く使用しないセルロースアシレート溶液（ドープ）の調製方法、セルロースアシレートフィルムの透明性、機械的強さが優れており、ハロゲン化銀写真感光材料や液晶画像表示装置用として有用である。
【図面の簡単な説明】
【図１】混合工程の断面模式図。
【図２】混合工程の断面模式図。
【図３】溶解工程の断面模式図。
【図４】連続混合工程及び連続有機溶媒分離工程の断面模式図。
【図５】連続混合工程、連続有機溶媒分離工程及び溶解工程の断面模式図。
【図６】連続混合工程、連続有機溶媒分離工程及び連続溶解工程の断面模式図。
【図７】分離有機溶媒の循環使用工程の模式図。
【図８】溶液流延製膜装置の断面模式図。
【符号の説明】
１ 有機溶媒
２ 冷却器
３ 混合釜
４ 撹拌機
５ 保温ジャケット
６ セルロースアシレート
７ サイロ
８ 切り出し送粉機
９ 有機溶媒導入口
１０ セルロースアシレート導入口
１１ 混合物排出口
１２ 膨潤した混合物
１３ 混合釜
１４ メッシュ
１５ 撹拌機
１６ セルロースアシレート
１７ サイロ
１８ 切り出し送粉機
１９ 有機溶媒導入口
２０ セルロースアシレート導入口
２１ 混合物排出口
２２ 有機溶媒
２３ 有機溶媒排出口
２４ 保温ジャケット
２５ 溶解釜
２６ 有機溶媒
２７ 撹拌機
２８ 熱交換機（加温器）
２９ 混合物導入口
３０ 有機溶媒導入口
３１ 混合物排出口
３２ 保温ジャケット
３３ 混合機
３４ 仕切板
３５ インラインミキサー
３６ 冷却器
３７ 有機溶媒導入口
３８ セルロースアシレート
３９ サイロ
４０ 切り出し送粉機
４１ セルロースアシレート導入口
４２ 有機溶媒分離器
４３ メッシュ
４４ 混合物
４５ 有機溶媒
４６ 混合物排出口
４７ 有機溶媒排出口
４８ 保温ジャケット
４９ 終点
５０ 溶解機
５１ 熱交換機（加温器）
５２ 有機溶媒導入口
５３ 仕切板
５４ 溶液排出口
６０ 混合機
６１ 有機溶媒分離器
６２ 冷却器
６３ 有機溶媒導入口
６４ セルロースアシレート導入口
６５ 混合物排出口
６６ 混合物導入口
６７ 混合物排出口
６８ 有機溶媒排出口
６９ ポンプ
７０ フィルター
７１ 支持体
７２ 加圧型ダイ
７３ ウェブ
７４ 剥離点
７５ テンター
７６ 巻き取り機
７７ 貯蔵釜
７８ ドープ
７９ ドープ導入口
８０ 添加剤導入口
８１ ドープ排出口
８２ ギヤポンプ
８３ 保温ジャケット
８４ 乾燥装置
８５ ロール（ロール群）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cellulose acylate film useful for a silver halide photographic light-sensitive material or a liquid crystal image display device, and a method for producing a cellulose acylate film.
[0002]
[Prior art]
Conventionally, chlorine-based hydrocarbons such as methylene chloride are used as the organic solvent for the cellulose triacetate solution used in the production of cellulose triacetate films used in silver halide photographic materials and liquid crystal image display devices. ing. Methylene chloride (boiling point 41 ° C.) has been conventionally used as a good solvent for cellulose triacetate, and is preferably used because it has a low boiling point in the film-forming and drying steps of the production process and is easy to dry. However, the use of chlorine-based compounds has recently been restricted, and an invention of a method for producing a cellulose triacetate film that can use or greatly reduce methylene chloride has been awaited. Conventionally, solvents other than methylene chloride that are known to be soluble in cellulose triacetate include acetone (boiling point 56 ° C.), methyl acetate (boiling point 56.3 ° C.), tetrahydrofuran (boiling point 65.4 ° C.), Examples include 1,3-dioxolane (boiling point 75 ° C.), nitromethane (boiling point 101 ° C.), 1,4-dioxane (boiling point 101 ° C.), epichlorohydrin (boiling point 116 ° C.), N-methylpyrrolidone (boiling point 202 ° C.). When these organic solvents were actually subjected to a dissolution test, some of them were not necessarily good solvents, and there were few that could be put to practical use, such as those having a concern of explosion and those having a high boiling point.
[0003]
Among the above solvents, acetone having a low boiling point merely swells cellulose triacetate by a usual method, but does not reach dissolution. In recent years, attempts have been made to make fibers and films by dissolving cellulose triacetate in acetone.
[0004]
J. et al. M.M. G. Cowie et al., In Die Makromolekulare Chemie, 143, 105-114 (1971), cooled a mixture of cellulose triacetate (degree of acetylation 60.1-61.3%) and acetone to -80 to -70 ° C. Later, it was reported that 0.5-5 wt% dilute solution was obtained by heating. Thus, the method of melt | dissolving by heating after cooling the mixture of a cellulose triacetate and a solvent is called the cooling dissolution method. In addition, Kenji Kamide et al., Spinning using the cooling dissolution method in “Dry spinning from cellulose triacetate in acetone”, Journal of the Textile Machinery Society, Vol. 34, No. 7, pp. 57-61 (1981). Discusses technology.
[0005]
In Japanese Patent Application Laid-Open Nos. 9-95544 and 9-95557, cellulose triacetate is obtained by a cooling dissolution method using an organic solvent substantially consisting of acetone or sharing acetone and another organic solvent against the background of the above technique. It is proposed to dissolve and apply to film production.
[0006]
In JP-A-9-95538, cellulose triacetate is dissolved by a cooling dissolution method using an organic solvent selected from ethers other than acetone, ketones or esters, and a film is prepared. 2-methoxyethyl acetate, cyclohexanone, ethyl formate, methyl acetate and the like are preferred.
[0007]
However, the above method requires a number of steps including a step of swelling a mixture of cellulose triacetate and a solvent, a step of cooling the swollen mixture, a step of heating and dissolving the cooled mixture, and at an industrial level. However, in practice, it takes a very long time to cool and warm, which is problematic in practical use.
[0008]
Japanese Patent Application Laid-Open No. 10-45916 as a method for shortening the dissolution time in the cooling dissolution method includes a step of mixing and swelling a polymer compound and a solvent, a step of cooling the swollen mixture, and heating the cooled product. In the step of dissolving, a method of increasing the cooling rate by introducing the mixture into a filament or flat plate into a refrigerant and cooling it has been proposed. Japanese Patent Application Laid-Open No. 10-45817 proposes a method for shortening the swelling time of the mixture by changing the size of cellulose triacetate particles from 0.1 mm to 4 mm. This is to shorten the swelling time by reducing the particle size of cellulose triacetate so as to accelerate the penetration of the solvent into the inside of the particle.
[0009]
Furthermore, Japanese Patent Application Laid-Open No. 10-45804 proposes a mixed fatty acid ester of cellulose that is soluble in a solvent such as acetone or methyl acetate, in which an acetyl group and an acyl group having 3 or more carbon atoms have a specific relationship. .
[0010]
[Problems to be solved by the invention]
As described above, the method of dissolving cellulose triacetate by cooling and dissolving is such that the mixture is cooled or heated, an insoluble material is formed, or the dissolution is not completed in one cooling and dissolving cycle. There is a practical problem that it takes too much time and labor, such as dissolution cannot be completed unless the same treatment is repeated. In the method of Japanese Patent Application Laid-Open No. 10-45916, it is necessary to stably transport the gelled mixture in the form of a thread or a plate, and the gelled mixture has a low strength, such as thread breakage or cutting of a sheet. There is a problem that it is difficult to stably convey. In the method disclosed in Japanese Patent Laid-Open No. 10-45804, those having a high degree of acyl group substitution have insufficient physical properties, and in practice, only those having a low degree of acyl group substitution can be used practically. It was. If the substitution degree of the acyl group is high, there is no need to use a special dissolution method such as a cooling dissolution method. However, if the substitution degree of the acyl group is small, it is necessary to dissolve by the cooling dissolution method. There was a problem that the process lengthened.
[0011]
Accordingly, the object of the present invention is to swell the mixture of cellulose triacetate and solvent, which has been a problem of the conventional cooling dissolution method, to cool the swollen mixture, and to heat the cooled and swollen mixture A method for preparing a cellulose acylate solution that can significantly reduce everything in terms of time and can greatly reduce or eliminate the use of chlorinated hydrocarbons such as methylene chloride, and cellulose acylate using the same It is providing the manufacturing method of a film, and a cellulose acylate film.
[0012]
[Means for Solving the Problems]
As a result of diligently examining improvements such as intermittent mixing, swelling, and dissolution processes, which required a long time for cooling and heating, which were the disadvantages of the cooling dissolution method, the present inventors cooled in advance to a low temperature. By mixing cellulose acylate with an organic solvent, and by mixing cellulose acylate with an organic solvent being transferred, it succeeded in significantly reducing the swelling time. It has been found that the object of the present invention is achieved by adding the swollen mixture to an organic solvent that has been adjusted to temperature, or by introducing the swollen mixture into the organic solvent being transferred.
[0013]
In addition to this, the cellulose acylate dissolution method of the present invention swells a mixture of a cooled organic solvent and a cellulose acylate at −100 to −10 ° C., and is suitable for the organic solvent to be used next. It dissolves by heating the mixture at a temperature of 120 ° C. The present invention is an improvement in that it takes a long time to dissolve in the conventional cooling dissolution method, and it is not mixed and then cooled, but cellulose acylate is mixed in a precooled solvent, An epoch-making method in which an organic solvent that has not participated in swelling is separated from the mixture using a separating means, the mixture is concentrated, and the concentrated mixture is mixed with a pre-warmed organic solvent to form a solution. is there. In addition, the continuous mixing, swelling, separation, dissolution and preparation method not only can greatly reduce time, but also efficiently obtain a cellulose acylate solution with good quality, that is, excellent solubility. Is possible. The separated organic solvent can be recycled and reused.
[0014]
  The present invention includes the following (1) to (10).
[0015]
(1)Non-chlorine system capable of swelling cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atomsA step of cooling the organic solvent to −100 to −10 ° C., a step of mixing the cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atoms and the cooled organic solvent, a step of swelling the mixture, and A method for preparing a cellulose acylate solution, comprising a step of heating and dissolving a swollen mixture.
[0016]
(2)Non-chlorine system capable of swelling cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atomsA step of cooling the organic solvent to −100 to −10 ° C., a step of mixing cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atoms and the cooled organic solvent, a step of swelling the mixture, and swelling A method for preparing a cellulose acylate solution, comprising: separating and concentrating a part of the organic solvent from the mixture by a separation means; and heating and dissolving the concentrated mixture.
[0017]
(3)Non-chlorine system capable of swelling cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atomsA step of cooling the organic solvent to −100 to −10 ° C., a step of mixing the cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atoms and the cooled organic solvent, a step of swelling the mixture, 0 A method for preparing a cellulose acylate solution comprising a step of mixing a swollen mixture with an organic solvent having the same composition as described above adjusted to a temperature of ˜120 ° C.
[0018]
(4) During transfer at -100 to -10 ° CNon-chlorine system capable of swelling cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atomsA step of swelling a mixture formed by continuously adding cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atoms to an organic solvent, separating the organic solvent from the swollen mixture by separation means A method for preparing a cellulose acylate solution, comprising a step of concentrating and a step of dissolving the mixture after concentration by heating.
[0019]
(5) During transfer at -100 to -10 ° CNon-chlorine system capable of swelling cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atomsA step of swelling a mixture formed by continuously adding a cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atoms to an organic solvent, a part of the organic solvent is separated from the swollen mixture by a separating means A method for preparing a cellulose acylate solution, comprising a step of separating and concentrating, and a step of mixing a mixture after concentration with an organic solvent having the same composition at 0 to 120 ° C. to form a solution.
[0020]
(6) During transfer at -100 to -10 ° CNon-chlorine system capable of swelling cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atomsA step of swelling a mixture formed by continuously adding a cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atoms to an organic solvent, a part of the organic solvent is separated from the swollen mixture by a separating means Preparation of a cellulose acylate solution comprising a step of separating and concentrating, and a step of mixing the organic solvent having the same composition as that described above while transferring the concentrated mixture at 0 to 120 ° C. to form a solution. Method.
[0021]
(7) The aboveNon-chlorine-based organic solvent capable of swelling cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atomsSolventContains at least one selected from methyl formate, ethyl formate, methyl acetate, ethyl acetate, amyl acetate, butyl acetate, acetone, methyl ethyl ketone, and cyclohexanoneIt is characterized by(1) to (6)ofEitherA method for preparing the cellulose acylate solution described in 1.
[0022]
(8) saidNon-chlorine system capable of swelling cellulose acylate having a hydroxyl group substituted with an acyl group having 2 to 5 carbon atomsThe organic solventIncludes lower alcohols with 1 to 6 carbon atomsThe method for preparing a cellulose acylate solution according to any one of (1) to (7), wherein
[0031]
(9) (1) to (8) To produce a solution cast film using the cellulose acylate solution according to any one of the above.
[0032]
(10) (9A cellulose acylate film formed by the method described in 1).
[0033]
The present invention will be described in detail.
[0034]
The first invention will be described with reference to FIG. FIG. 1 shows an example of claim 1 and is a schematic sectional view of a mixing step. The organic solvent 1 used in the present invention is cooled in advance to −100 to −10 ° C. with the cooler 2, put into the mixing pot 3 with the heat insulation jacket 5 through the organic solvent inlet 9, and stirred with the stirrer 4 while silo. When the cellulose acylate 6 stored in 7 is cut out and transported by the powder feeder 8 and charged into the mixing vessel 3 through the cellulose acylate inlet 10 and mixed, the cellulose acylate immediately swells. By introducing cellulose acylate into the low-temperature organic solvent of the present invention, the swelling time can be greatly reduced as compared with the conventional method of cooling after mixing cellulose acylate and organic solvent. The swollen mixture is sent from the mixture outlet 11 to the next dissolution step. In the dissolving step, the swollen mixture may be heated and dissolved, and the conventional swollen mixture may be heated. In addition to mixing the cellulose acylate with the cooled organic solvent in this example, the cellulose acylate may be added to and mixed with the organic solvent cooled to the cellulose acylate.
[0035]
The second invention will be described with reference to FIG. FIG. 2 shows an example of claim 2, which is a schematic cross-sectional view of the mixing step, and is fixed to the lower part of the mixing pot 13 in a cylindrical shape inside the mixing pot 13 similar to the mixing pot 3 of FIG. 1. Equipped with a mesh (an example of separation means) 14, a stirrer 15, a heat insulation jacket 24, an organic solvent inlet 19, a cellulose acylate inlet 20, a mixture outlet 21, a separated organic solvent outlet 23, and the like. ing. The organic solvent that is not involved in the swelling is separated from the swollen mixture 12 that has already been cooled to −100 to −10 ° C. through the mesh 14, and the organic solvent 22 separated outside the mesh 14 is removed from the organic solvent outlet 23. By discharging out of the system, the swollen mixture 12 can be concentrated. As the separating means, in addition to the cylindrical mesh 14 fixed to the mixing kettle 13 as shown in FIG. 2, such as a bowl-shaped mesh (not fixed) rotating on the opposite side to the rotation of the agitator 15 However, any separation can be used without limitation. The size of the holes in the mesh may be about 0.1 to 10 mm, and in order to prevent clogging, the surface may be scratched by applying vibration or a scraper, etc. Can be used without restrictions. The feature of the present invention is that the cellulose acylate can be made to swell faster by adding cellulose acylate into a large amount of organic solvent in the mixing step, and the cellulose acylate can remain in the organic solvent (a lump of powder). It is also a feature that only the surface is dissolved or swelled and does not become a powdered state), and the swelling efficiency is good. The concentrated mixture is discharged from the mixture discharge port 21 and introduced into the next melting pot (not shown in the figure) to be dissolved. In the dissolving step, it may be dissolved in a concentrated state, or it may be diluted to the concentration of the finished dope. In addition to this example, a cooled organic solvent may be added to cellulose acylate. In addition, 16 is a cellulose acylate, 17 is a silo, and 18 is a cutting and feeding machine.
[0036]
A third invention will be described with reference to FIG. FIG. 3 shows an example of claim 3 and is a schematic cross-sectional view of the melting step. An organic solvent having the same composition as the organic solvent for cooling that has been previously adjusted to 0 to 120 ° C. with a heat exchanger (heater) 28 (the organic solvent for 0 to 120 ° C. has the same composition as the organic solvent used for cooling, and thereafter Are of the same composition unless otherwise noted) are introduced into the dissolution vessel 25 through the organic solvent inlet 30 and the cooled and swollen mixture at −100 to −10 ° C. is introduced into the dissolution vessel 25 through the mixture introduction port 29. Add and dissolve. When the mixture is added to the conditioned organic solvent 26, the cellulose acylate dissolves almost instantaneously, and the dissolution time can be greatly shortened. In addition, it has almost no dissolved residue and is excellent in solubility. An additive may be added from the organic solvent inlet 30. The dissolved mixture is sent from the mixture outlet 31 to a storage tank (not shown in the figure). In addition to this method, a conditioned organic solvent may be added to the mixture. In addition, 27 is a stirrer and 32 is a heat insulation jacket.
[0037]
A fourth invention will be described with reference to FIG. FIG. 4 shows an example of claim 4 and is a schematic cross-sectional view of a continuous mixing step and a continuous organic solvent separation step. The organic solvent cooled to −100 to −10 ° C. by the cooler 36 is introduced into the mixer 33 inclined through the organic solvent introduction port 37, and the organic solvent is added to the in-line mixer (as an example of the transportation means of the mixture) 35. , The cellulose acylate 38 is cut out from the silo 39 and sent by the powder feeder 40, and the cellulose acylate is transferred from the cellulose acylate inlet 41 to the organic solvent being transferred in the mixer 33. Is added (which may be used hereinafter) and flows while mixing with the transfer of the organic solvent by the in-line mixer 35 rotating along the partition plate 34 to swell the cellulose acylate, and the mixer 33 The organic solvent is introduced into the organic solvent separator 42 having the mesh 43 as the separation means at the end point 49 of the organic solvent, and the organic solvent not involved in the swelling is introduced. 45 was concentrated mixture 44 is separated through the mesh 43, to introduce the mixture 44 enriched mixture outlet 46 to the next dissolving tank (not shown in the Figure). The separated organic solvent 45 is discharged from the organic solvent outlet 47. Next, the concentrated mixture may be dissolved by heating in the next dissolution vessel, or may be dissolved and diluted in a temperature-controlled organic solvent. When the cellulose acylate is mixed with the organic solvent being transferred, the addition rate of the cellulose acylate may be about 0.5 to 40% by weight, preferably 1 to 20% by weight as the concentration with respect to the instantaneous organic solvent. is there. The lower the concentration at the time of charging, the faster and more effective the swelling speed. The flow of organic solvent is 0.01-5m^Three/ Second is preferred, 0.1-1 m^Three/ Second is particularly preferred. In order to make the organic solvent and the mixture flow, the mixture can be transferred by tilting the mixer. However, it is a very preferable example to use a rotary mixer that does not require power such as an in-line mixer as shown in FIG. Moreover, you may make it transfer using the screw which is used for an extruder. Further, the shape of the mixer is not limited as long as it is a bowl shape, a pipe shape, or a box shape as long as the organic solvent and the mixture easily flow. Moreover, even if it is linearly long, it may be a spelled folded shape or a loop shape. A heat insulation jacket 48 is preferably attached to the outside of the mixer. In the case of a zigzag or loop shape, it is preferable that they are in contact with each other because the temperature loss is small and the efficiency can be improved. The organic solvent separator 42 also has a heat insulation jacket 48. The organic solvent separator 42 can transfer the organic solvent and the mixture only by tilting, but to transfer the concentrated and hard-to-flow mixture, use an inline mixer 35 that does not require power as shown in FIG. Is preferred. Further, the mixture may be forcibly transferred with a screw, or the mixture may be carried on a mesh belt conveyor and separated from the organic solvent on the way. The separation means may be separated by the mesh 43 in the organic solvent separator 42 as shown in FIG. 4. However, even if the mesh plate is formed in a cylindrical shape and the mixture is transferred outside, the cylindrical mesh is also used. An in-line mixer or a screw may be installed on the inside of the inside, and the mixture may be fed while rotating, so that the organic solvent 45 not involved in the swelling is separated to the outside. The concentrated mixture is sent to the dissolution process from the mixture outlet 46, and dissolution can be performed by any method that can be dissolved, and even if the mixture is heated, it is dissolved in a pre-conditioned organic solvent and diluted. Also good.
[0038]
A fifth invention will be described with reference to FIG. FIG. 5 shows an example of claim 5 and is a schematic cross-sectional view of a continuous mixing step, a continuous organic solvent separation step, and a dissolution step. The mixing and organic solvent separation process of FIG. 5 is the same as that of FIG. 4, and the dissolution process is the same as that of FIG. The concentrated mixture is transferred through a pipe connected to the mixture outlet 46 in FIG. 4 and the mixture inlet 29 in FIG. 3. The fifth aspect of the invention is a method in which the mixture 44 concentrated in the organic solvent separator 42 is introduced into the dissolution vessel 25 in which the organic solvent whose temperature has been adjusted to 0 to 120 ° C. has already been introduced, and is dissolved and diluted. In this method, the time for swelling and the time for dissolving can be greatly reduced as compared with the conventional method. An additive may be introduced from the organic solvent inlet 30.
[0039]
A sixth invention will be described with reference to FIG. FIG. 6 shows an example of claim 6 and is a schematic cross-sectional view of a continuous mixing step, a continuous organic solvent separation step, and a continuous dissolution step. The mixing and organic solvent separation steps in FIG. 6 are the same as those in FIG. 4 or FIG. The dissolution process of FIG. 6 is the same method as the mixing process, unlike the above-described dissolution process. An organic solvent whose temperature is adjusted to 0 to 120 ° C. is introduced from the heat exchanger (heater) 51 through the organic solvent inlet 52 of the dissolver 50, and the organic solvent is transferred while rotating together with the in-line mixer 35 in the dissolver 50. Separately, the mixture 44 concentrated by the organic solvent separator 42 is introduced from the mixture introduction port 49 through the mixture discharge port 46, and is dissolved and diluted in the organic solvent transferred while rotating. In the dissolver 50 of FIG. 6, the same one as the in-line mixer (as a means for transporting the mixture) 35 of the mixer 33 and the organic solvent separator 42 is installed. The in-line mixer has good mixing efficiency and can be preferably used in the present invention. As described above, other methods can be used as well. While reaching the solution outlet 54, the mixture is completely dissolved in an organic solvent to become a cellulose acylate solution (hereinafter sometimes referred to as a dope), and the next storage tank (not shown in the drawing). ). Reference numeral 53 denotes a partition plate.
[0040]
The seventh invention will be described with reference to FIG. FIG. 7 shows an example of claim 7, and is a schematic diagram of the circulation and use step of the separated organic solvent. The mixer 60 and the organic solvent separator 61 which become the swollen mixture in FIG. 7 are the same as the mixer 33 and the organic solvent separator 42 in FIGS. The organic solvent cooled by the cooler 62 is introduced from the organic solvent introduction port 63 of the mixer 60. Separately, cellulose acylate is introduced from the cellulose acylate introduction port 64 and mixed, and the swollen mixture is mixed with the mixture discharge port 65. To the organic solvent separator 61 through the mixture inlet 66, the organic solvent is separated, the mixture is concentrated, and the concentrated mixture is sent from the mixture outlet 67 to the next dissolution step. The separated organic solvent is discharged from the organic solvent outlet 68 and sent to the filter 70 by the pump 69, where impurities are removed and sent to the cooler 62 to reuse the organic solvent.
[0041]
It should be noted that the present invention is not limited to the contents of the description of the above drawings.
[0042]
Throughout, the container may be filled with an inert gas such as nitrogen gas in the mixing, swelling, and dissolving steps of the present invention. Mixing kettles, melting kettles, other mixers, melting machines, etc. are preferably not only provided with a heat insulation jacket to prevent condensation, but also piping, valves, inlets, etc. are preferably provided with a heat insulation jacket. In addition, it is preferable to use a pressure-resistant container that can withstand slight pressurization of the mixing or dissolving apparatus.
[0043]
The amount of cellulose acylate added to the organic solvent in the mixer of the present invention is 0.5 to 40% by weight, preferably 1 to 40% by weight because it is concentrated or diluted later. In the dissolver, the concentration is 10 to 40% by weight, and 10 to 35% by weight is a preferable concentration for final preparation. The final concentration when used is 10 to 40% by weight, preferably 15 to 35% by weight.
[0044]
Other inventions will be described below.
[0045]
In the cellulose acylate of the present invention, the substitution degree of cellulose with a hydroxyl group satisfies all of the following formulas (I) to (IV).
[0046]
(I) 2.6 ≦ A + B ≦ 3.0
(II) 2.0 ≦ A ≦ 3.0
(III) 0 ≦ B ≦ 0.8
(IV) 1.9 <AB
Here, A and B represent the substituent of the acyl group substituted by the hydroxyl group of cellulose, A is the substitution degree of an acetyl group, and B is the substitution degree of a C3-C5 acyl group. . Cellulose has three hydroxyl groups in one glucose unit, and the above number represents the degree of substitution with respect to the hydroxyl group 3.0, and the maximum degree of substitution is 3.0. Cellulose triacetate generally has a substitution degree of A of 2.6 or more and 3.0 or less (in this case, there is a maximum of 0.4 hydroxyl groups not substituted), and B = 0 is cellulose triacetate. The cellulose acylate of the present invention has cellulose triacetate whose acyl groups are all acetyl groups, acetyl groups of 2.0 or more, acyl groups of 3 to 5 carbon atoms of 0.8 or less, and unsubstituted hydroxyl groups. The thing below 0.4 is preferable. In the case of an acyl group having 3 to 5 carbon atoms, 0.3 or less is particularly preferable from the viewpoint of physical properties.
[0047]
The degree of substitution can be obtained by calculating the degree of binding of acetic acid substituted with a hydroxyl group of cellulose and a fatty acid having 3 to 5 carbon atoms. As a measuring method, it can carry out according to ASTM D-817-91.
[0048]
The degree of polymerization (viscosity average) of the cellulose acylate used in the present invention is preferably from 200 to 700, and particularly preferably from 250 to 550. In general, a cellulose acylate film containing cellulose triacetate, a fiber or a molded product is required to have a degree of polymerization of 200 or more in order to have a tough mechanical strength. Hiroshi Sobue, Nobuhiko Ueda, “Cellulose Handbook “Asakura Shobo (1958)”, “Mr. Marusawa, Kazuo Uda”, “Plastic Materials Course 17”, Nikkan Kogyo Shimbun (1970). The degree of polymerization of the cellulose acylate film of the present invention is particularly preferably 250 to 350. The viscosity average degree of polymerization can be measured with an Ostwald viscometer, and is determined from the measured intrinsic viscosity [η] of cellulose acylate by the following formula.
[0049]
DP = [η] / Km
(Where DP is the viscosity average degree of polymerization and Km is a constant of 6 × 10^-Four)
Examples of cellulose as a raw material for cellulose acylate used in the present invention include cotton linter and wood pulp, but any cellulose acylate obtained from any raw material cellulose may be used, or a mixture thereof may be used.
[0050]
The cellulose triacetate used in the present invention is preferably a photographic grade, and a commercially available photographic grade can be obtained satisfying qualities such as viscosity average degree of polymerization and degree of acetylation. Manufacturers of photographic grade cellulose triacetate include Daicel Chemical Industries, Ltd., Coatles, Hoechst, Eastman Kodak, etc., and any photographic grade cellulose triacetate can be used.
[0051]
The cellulose acylate having an acetyl group and an acyl group having 3 to 5 carbon atoms used in the present invention is also called a cellulose mixed fatty acid ester. Other acyl groups having 3 to 5 carbon atoms of the acetyl group are propionyl groups (C₂H_FiveCO-), butyryl group (C_ThreeH₇CO-) (n-, iso-), valeryl group (C_FourH₉CO-) (n-, iso-, sec-, tert-), of which n-substituted ones are preferred from the viewpoint of mechanical strength when formed into a film, ease of dissolution, etc., and in particular, an n-propionyl group Is preferred.
[0052]
Moreover, when the substitution degree of an acetyl group is low, mechanical strength and heat-and-moisture resistance deteriorate. When the degree of substitution of the acyl group having 3 to 5 carbon atoms is high, the solubility in a mixed solution of methyl acetate and acetone is improved. However, if the degree of substitution is within the above range, good physical properties are exhibited.
[0053]
As an acylating agent for these acyl groups, an organic acid such as acetic acid or methylene chloride is used as an organic solvent as a reaction solvent in the case of an acid anhydride or acid chloride. As the catalyst, a protic catalyst such as sulfuric acid is preferably used. The acylating agent is an acid chloride (eg CH_ThreeCH₂In the case of COCl), basic compounds are used. The most common method in the industry is to use cellulose for fatty acids corresponding to acetyl groups and other acyl groups (acetic acid, propionic acid, butyric acid, valeric acid) or their anhydrides (acetic anhydride, propionic anhydride, butyric anhydride). The cellulose acylate is synthesized by acylation with a mixed organic acid component containing valeric anhydride.
[0054]
The specific method for producing the cellulose acylate used in the present invention can be synthesized, for example, by the method described in JP-A-10-45804.
[0055]
Next, the organic solvent for cellulose acylate of the present invention will be described.
[0056]
Organic solvents that can swell cellulose acylate used in the present invention are esters such as methyl formate, ethyl formate, methyl acetate, ethyl acetate, amyl acetate, butyl acetate, ketones such as acetone, methyl ethyl ketone, cyclohexanone, 1, It is at least one selected from cyclic ethers such as 3-dioxolane, 1,4-dioxane, and tetrahydrofuran, and two or more types may be used in combination. The organic solvent preferably used in the present invention is ethyl formate, methyl acetate and acetone, and particularly preferred combinations are ethyl formate and acetone and methyl acetate and acetone. When used in combination, these are excellent organic solvents that are very swellable or soluble. The ratio of these solvents to the total organic solvent is such that at least one solvent selected from methyl acetate and ethyl formate is 60 to 95% by weight, acetone is 5 to 40% by weight, and preferably the former is 65 to 75%. The latter is 25 to 35% by weight. By using this ratio, not only the solubility is excellent, but also the castability when casting a cellulose acylate solution (hereinafter sometimes referred to as a dope) on the support, and the flatness of the film are also excellent. Can be made. Two or more of the former solvents may be used in combination. Among them, a combination of methyl acetate and acetone is most preferable, and a film having good solubility and excellent transparency can be obtained.
[0057]
In addition to the organic solvent of the present invention, the dope used in the present invention may contain fluoroalcohol or methylene chloride in an amount of 10% by weight or less of the total amount of the organic solvent of the present invention. This is preferable for speeding up the process. The fluoroalcohol has a boiling point of 165 ° C or lower, preferably 111 ° C or lower, and more preferably 80 ° C or lower. The fluoroalcohol has about 2 to 10 carbon atoms, preferably about 2 to 8 carbon atoms. The fluoroalcohol is a fluorine atom-containing aliphatic alcohol, which may or may not have a substituent. As the substituent, an aliphatic substituent or an aromatic substituent containing or not containing a fluorine atom is preferable. Such a fluoroalcohol is, for example (the following is the boiling point in parentheses)
2-fluoroethanol (103 ° C.),
2,2,2-trifluoroethanol (80 ° C.),
2,2,3,3-tetrafluoro-1-propanol (109 ° C.),
1,3-difluoro-2-propanol (55 ° C.),
1,1,1,3,3,3-hexa-2-methyl-2-propanol (62 ° C.),
1,1,1,3,3,3-hexafluoro-2-propanol (59 ° C.),
2,2,3,3,3-pentafluoro-1-propanol (80 ° C.),
2,2,3,4,4,4-hexafluoro-1-butanol (114 ° C.),
2,2,3,3,4,4,4-heptafluoro-1-butanol (97 ° C.),
Perfluoro-tert-butanol (45 ° C.),
2,2,3,3,4,4,5,5-octofluoro-1-pentanol (142 ° C.),
2,2,3,3,4,4-hexafluoro-1,5-pentanediol (111.5 ° C.),
3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol (95 ° C.),
2,2,3,3,4,5,5,6,6,7,7,8,8,8-pentadecafluoro-1-octanol (165 ° C.),
1- (pentafluorophenyl) ethanol (82 ° C.),
2,3,4,5,6-pentafluorobenzyl alcohol (115 ° C.),
Etc. are included. These fluoroalcohols may be used alone or in combination.
[0058]
The dope of the present invention may contain a lower alcohol having 1 to 6 carbon atoms or a saturated hydrocarbon having 4 to 8 carbon atoms. For example, examples of the lower alcohol include methanol, ethanol, propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, and cyclohexanol. Of these, methanol, ethanol, and n-butanol are preferable. Examples of the hydrocarbon having 4 to 8 carbon atoms include cyclobutane, cyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane and the like, and cyclohexane is preferable. As content, it is preferable to make a lower alcohol or a hydrocarbon into 20 weight% or less with respect to the total amount of organic solvents. When the cellulose acylate solution containing these organic solvents is cast by casting, the strength of the film is strong even in a state containing a large amount of residual solvent, and it is easy to peel off from the belt or drum of the support.
[0059]
The viscosity of the cellulose acylate solution of the present invention may be in a range where casting can be performed at the time of film formation, and is usually preferably adjusted to a range of 5 to 2000 poise.
[0060]
Various additives according to the application can be added to the cellulose acylate solution of the present invention in each preparation step. Further, the addition may be performed at any time in the dope preparation process, but may be performed by adding an additive to the final preparation process of the dope preparation process. Cellulose acylate films for silver halide photographic light-sensitive materials are provided with plasticizers, colorants for preventing light piping, or UV inhibitors to improve mechanical properties or impart water resistance, and for liquid crystal display devices. It is preferable to add an antioxidant or the like that imparts heat and humidity resistance.
[0061]
As the plasticizer, phosphoric acid ester, carboxylic acid ester, glycolic acid ester and the like are preferably used. Examples of phosphate esters include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, and tributyl phosphate. Examples of carboxylate esters include dimethyl phthalate. , Diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diethyl hexyl phthalate, acetyl triethyl citrate, acetyl tributyl citrate, butyl oleate, methyl acetyl ricinoleate, dibutyl sebacate, trimellitic acid ester, etc. As triacetin, tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, Chill phthalyl ethyl glycolate, and the like butyl phthalyl butyl glycolate. Of these, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diethyl hexyl phthalate, triacetin, and ethyl phthalyl ethyl glycolate are preferable. In particular, triphenyl phosphate, diethyl phthalate, and ethyl phthalyl ethyl glycolate are preferable. These plasticizers may be used alone or in combination of two or more. The addition amount of the plasticizer is preferably 5 to 30% by weight, particularly preferably 8 to 16% by weight, based on the cellulose acylate. These compounds may be added together with cellulose acylate and a solvent during the preparation of the cellulose acylate solution, or may be added during or after the solution preparation.
[0062]
Further, a compound represented by the following general formula (I) (II) or (III) may be added.
[0063]
[Chemical 1]

[0064]
In the general formulas (I), (II), and (III), R is an alkyl group having 1 to 4 carbon atoms. Examples of the compound represented by the general formula (I), (II) or (III) include 2,2′-methylenebis (4,6-di-tert-butylphenyl) sodium phosphate (ADK STAB NA-10, Asahi Denka Co., Ltd.) and bis (p-ethylbenzylidene) sorbitol (NC-4, Mitsui Toatsu Chemical Co., Ltd.) are included.
[0065]
As the antioxidant, those represented by the following general formula (IV) are used.
[0066]
[Chemical formula 2]

[0067]
R in the general formula (IV)₁Represents an alkyl group, R₂, R_ThreeAnd X are a hydrogen atom, alkyl group, alkenyl group, aryl group, heterocyclic group, alkoxy group, alkenoxy group, aryloxy group, alkylthio group, alkenylthio group, arylthio group, heterocyclic oxy group, hydroxy group, amino group, respectively. Represents a group, a carbamoyl group, a sulfamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a halogen atom, a nitro group, a cyano group, an acyl group, or an acyloxy group. m represents an integer of 0-2. R₂, R_ThreeAnd X may be the same as or different from each other. Examples of the alkyl group include linear, branched, or cyclic alkyl groups such as methyl, ethyl, propyl, iso-propyl, tert-butyl, cyclohexyl, tert-hexyl, tert-octyl, dodecyl, hexadecyl, octadecyl, and benzyl. And the alkenyl group represents a linear, branched, or cyclic alkenyl group such as vinyl, allyl, 2-pentenyl, cyclohexenyl, hexenyl, dodecenyl, octadecenyl, etc., and the aryl group includes, for example, phenyl, Represents a benzene monocyclic or condensed polycyclic aryl group such as naphthyl and anthranyl, and the heterocyclic group includes, for example, a nitrogen atom such as furyl, pyrrolyl, imidazolyl, pyridyl, purinyl, chromanyl, pyrrolidyl, morpholinyl, sulfur atom, oxygen At least of atoms One represents a group consisting of 5-7 membered ring containing. Of these, hindered phenol compounds are preferred, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]. Triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl- 4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2,2- Thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadec -3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 1,3 , 5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanate Examples include nurate. In particular, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] is most preferred. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di-tert A phosphorus processing stabilizer such as -butylphenyl) phosphite may be used in combination. The amount of these compounds added is preferably 1 ppm to 1.0% by weight, more preferably 10 to 1000 ppm, based on the cellulose acylate.
[0068]
Examples of the coloring agent for preventing light piping include compounds represented by the following general formulas (V) and (VI).
[0069]
[Chemical Formula 3]

[0070]
In the formulas (V) and (VI), X represents an oxygen atom or NR_{twenty three}Represents. R₁~ R₈, R₁₂~ R_{twenty three}Are hydrogen atom, hydroxyl group, aliphatic group, aromatic group, heterocyclic group, halogen atom, cyano group, nitro group, COR, respectively.₉, COOR₉, NR₉R_Ten, NR_TenCOR₁₁, NR_TenSO₂R₁₁, CONR₉R_Ten, SO₂NR₉R_Ten, COR₁₁, SO₂R₁₁, OCOR₁₁, NR₉CONR_TenR₁₁, CONHSO₂R₁₁Or SO₂NHCOR₁₁Represents R₉, R_TenEach represents a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group;₁₁Represents an aliphatic group, an aromatic group, or a heterocyclic group.
[0071]
R₁~ R_{twenty three}Is an alkyl group having 1 to 20 carbon atoms (for example, methyl, ethyl, n-butyl, isopropyl, 2-ethylhexyl, n-decyl, n-octadecyl), cyclohexane having 1 to 20 carbon atoms. Represents an alkyl group (for example, cyclobenzyl, cyclohexyl) or an allyl group, and these further represent a substituent (for example, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxylic acid group, an aryl group having 6 to 10 carbon atoms, a carbon number) An amino group having 0 to 20 carbon atoms, an amide group having 1 to 20 carbon atoms, a carbamoyl group having 1 to 20 carbon atoms, an ester group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms or an aryloxy group; It may have a 20 sulfonamido group, a sulfamoyl group having 0 to 20 carbon atoms, or a 5- or 6-membered heterocyclic ring.₁~ R_{twenty three}Represents an aryl group such as phenyl or naphthyl having 6 to 10 carbon atoms, and the above-described substituents and methyl, ethyl, n-butyl, tert-butyl, octyl having 1 to 20 carbon atoms. It may have a substituent consisting of an alkyl group such as R₁~ R₁₁The heterocyclic group represented by represents a 5- or 6-membered heterocyclic ring and may have the above-described substituent. Preferred examples (V-1) to (V-25) and (VI-1) to (VI-4) of the compounds represented by the general formulas (V) and (VI) are shown in the following chemical formulas 4 to 9. .
[0072]
[Formula 4]

[0073]
[Chemical formula 5]

[0074]
[Chemical 6]

[0075]
[Chemical 7]

[0076]
[Chemical 8]

[0077]
[Chemical 9]

[0078]
The content of the colorant is preferably from 10 to 1000 ppm, more preferably from 50 to 500 ppm, by weight with respect to cellulose acylate. By containing the colorant in this way, light piping of the cellulose acylate film can be reduced, and yellowness can be improved. These compounds may be added together with cellulose acylate and a solvent during the preparation of the cellulose acylate solution, or may be added during or after the solution preparation.
[0079]
In addition, various additives may be further added to the cellulose acylate solution of the present invention as necessary at any stage after preparation of the solution. Additives include heat stabilizers such as ultraviolet absorbers, kaolin, talc, diatomaceous earth, quartz, calcium carbonate, barium sulfate, titanium oxide, inorganic fine particles such as alumina, alkaline earth metal salts such as calcium and magnesium, Antistatic agents, flame retardants, lubricants, oils, etc.
[0080]
Prior to casting, it is preferable to filter off foreign matters such as undissolved matter, dust, and impurities using a suitable filter medium such as a wire mesh or flannel.
[0081]
A method for producing a film using the cellulose acylate solution of the present invention will be described. For the method and equipment for producing the cellulose acylate film of the present invention, a solution casting film forming method and a solution casting film forming apparatus conventionally used for producing a cellulose triacetate film are used. FIG. 8 is a schematic cross-sectional view of a solution casting film forming apparatus, and a solution casting film forming method and apparatus will be briefly described using this. The dope (cellulose acylate solution) prepared from the above-described dissolving machine (kettle) is temporarily stored in the storage kettle 77, and bubbles contained in the dope are defoamed or finally prepared. The dope 78 is fed from the dope discharge port 81 to the pressurizing die 72 through the pressurizing quantitative gear pump 82 that can feed the liquid quantitatively with high accuracy, for example, by the rotation speed, and the dope travels endlessly from the base (slit) of the pressurizing die 72. The dope film (also referred to as a web) is peeled off from the support 71 at a peeling point 74 that is uniformly cast on the support 71 in the cast portion and the support is almost completely turned. The paper is transported by the tenter 75 while being held by the clip and dried by the tenter 75, and then transported by the roll group 85 of the drying device 84 to finish the drying, and is wound up to a predetermined length by the winder 76. Reference numeral 79 denotes a dope introduction port, 80 denotes an additive introduction port, and 83 denotes a heat insulation jacket. The combination of the tenter and the roll group dryer varies depending on the purpose. In the solution casting film forming method used for the silver halide photographic light-sensitive material, an undercoat layer, an antistatic layer, an antihalation layer, a protective layer, in addition to the apparatus described in the solution casting film forming apparatus of FIG. In many cases, a coating apparatus is added for surface processing of the support.
[0082]
The casting method useful in the present invention includes a method in which the prepared dope is uniformly extruded onto a support from a pressure die, and a doctor blade that adjusts the film thickness of the dope once cast on the support with a blade. There are a method and a method using a reverse roll coater which adjusts with a reversely rotating roll, but a method using a pressure die is preferable. The pressure die includes a coat hanger type and a T die type, and any of them can be preferably used. In addition to the methods listed here, various known methods for casting a cellulose triacetate solution (for example, JP-A-61-94724, JP-A-61-148013, JP-A-4-85011, 4-286611, 5-185443, 5-185445, 6-278149, 8-207210 and the like, and the difference in the boiling point of the solvent used can be preferably used. By setting each condition in consideration of the above, effects similar to those described in the respective publications can be obtained.
[0083]
The endlessly running support used for producing the cellulose acylate film of the present invention includes a drum whose surface is mirror-finished by chrome plating and a stainless steel belt whose surface is mirror-finished by surface polishing (even though it is called a band) Good) is used.
[0084]
One or two or more pressure dies used for producing the cellulose acylate film of the present invention may be installed above the support. Preferably 1 or 2 groups. When two or more are installed, the dope amount to be cast may be divided into various ratios for each die, and the dope is fed to the dies from each of a plurality of precision quantitative gear pumps.
[0085]
The drying of the dope on the support related to the production of the cellulose acylate film of the present invention is generally a method of applying hot air from the surface side of the support (drum or belt), that is, the surface of the web on the support, A method of applying hot air from the back of the drum or belt, contacting a temperature-controlled liquid from the back of the belt or drum opposite the dope casting surface, and heating the drum or belt by heat transfer to control the surface temperature. Although there is a heat method, the back surface liquid heat transfer method is preferable.
[0086]
The surface temperature of the support before casting may be any number as long as it is not higher than the boiling point of the solvent used for the dope. However, in order to promote drying and to lose fluidity on the support, the temperature may be set to 1 to 10 ° C lower than the boiling point of the lowest boiling solvent used. preferable.
[0087]
The speed at which the cellulose acylate film is produced varies depending on the length of the belt, the drying method, the composition of the dope solvent, etc., but is almost determined by the amount of residual solvent at the time when the web is peeled from the belt. In other words, if the solvent concentration in the vicinity of the belt surface in the thickness direction of the dope film is too high, the dope remains on the belt when it is peeled off, which hinders the next casting. This is because the web strength is required to withstand the peeling force. The amount of residual solvent at the time of peeling differs depending on the drying method on the belt or drum, and the method of transferring heat from the belt or the back of the drum is more effective than the method of drying by blowing air from the dope surface. Can be reduced.
[0088]
With respect to the film drying method relating to the production of the cellulose acylate film of the present invention, the drying method of the solution casting film forming method described above is preferred. Drying is performed by a method of applying wind at a predetermined temperature to both surfaces of the web (film) being conveyed or a method using a heating means such as a microwave. Since rapid drying may impair the flatness of the web (film), it is preferable to dry at a temperature at which the solvent does not foam in the initial stage of drying, and to dry at a high temperature after the drying proceeds.
[0089]
In the drying process after peeling from the support, the film tends to shrink in the width direction by evaporation of the solvent. Shrinkage increases with drying at higher temperatures. In order to improve the flatness of the finished film, it is preferable to dry while suppressing the shrinkage as much as possible. From this point, for example, a method of drying the entire drying process or a part of the process as shown in Japanese Patent Application Laid-Open No. 62-46625 while holding the width at both ends of the web with a clip in the width direction (tenter method) ) Is preferred.
[0090]
Further, there is a method of positively stretching in the width direction. In the present invention, for example, JP-A-62-115035, JP-A-4-152125, JP-A-4284221, JP-A-4-298310, etc. The stretching method described in 1 can also be used.
[0091]
The drying temperature in the drying step of the cellulose acylate film of the present invention is preferably 40 to 250 ° C, particularly preferably 70 to 180 ° C. The drying temperature, the amount of drying air, and the drying time vary depending on the solvent used, and may be appropriately selected according to the type and combination of the solvents used. The amount of residual solvent in the final finished film is preferably 2% by weight or less, and more preferably 0.4% by weight or less in order to obtain a film having good dimensional stability.
[0092]
These steps from casting to post-drying may be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas.
[0093]
The winder relating to the production of the cellulose acylate film of the present invention may be a commonly used winder such as a constant tension method, a constant torque method, a taper tension method, a program tension control method with a constant internal stress. It can be wound up by the method.
[0094]
The thickness (after drying) of the cellulose acylate film of the present invention varies depending on the purpose of use, but is usually in the range of 5 to 500 μm, more preferably in the range of 40 to 250 μm, and most preferably in the range of 60 to 125 μm. preferable. The film thickness may be adjusted by adjusting the solid content concentration contained in the dope, the slit gap of the die base, the extrusion pressure from the die, the support speed, and the like so as to obtain a desired thickness.
[0095]
<Measurement method of acyl group substitution degree and viscosity average polymerization degree>
1) Degree of substitution of acyl group of cellulose acylate;
The substitution degree of the acyl group shall be measured by a saponification method. The dried cellulose acylate was precisely weighed and dissolved in a mixed solvent of 70 ml of acetone and 30 ml of dimethyl sulfoxide, and then 50 ml of acetone was further added. While stirring, 30 ml of 1N aqueous sodium hydroxide solution is added and saponified at 25 ° C. for 2 hours. Add 100 ml of hot water, add phenolphthalein as an indicator, and titrate excess sodium hydroxide with 1N aqueous sulfuric acid (concentration factor; F). A blank test is performed by the same method as described above. The supernatant of the solution after titration was diluted to 100, and the composition of the organic acid was measured by a conventional method using ion chromatography. The acylation substitution degree was calculated from the titration result and the acid composition analysis by ion chromatography as follows.
[0096]
T [A + B] = (EM) × F / (1000 × W)
A = {162.14 × T [A + B]} / {1-42.14 × T [A + B] + (1−56.06 × T [A + B]) × (Cb / Ca)}
B = A × (Cb / Ca)
here,
T [A + B]: Total organic acid amount (mol / g)
E: Blank test titration (ml)
M: Sample titration (ml)
F: 1N sulfuric acid factor
W: Sample weight (g)
Ca: Amount of acetic acid (mol) measured by ion chromatography
Cb: amount of organic acid having 3 to 5 carbon atoms (mol) measured by ion chromatography
Cb / Ca: molar ratio of acetic acid to other organic acids
A: Degree of substitution of acetyl group
B: Degree of substitution of acyl group having 3 to 5 carbon atoms
It is.
[0097]
2) Viscosity average polymerization degree of cellulose acylate (DP)
About 0.2 g of completely dried cellulose acylate is accurately weighed and dissolved in 100 ml of a mixed solvent of methylene chloride and ethanol (weight ratio 9: 1). This is measured by an Ostwald viscometer at 25 ° C., and the number of seconds of fall is measured, and the degree of polymerization is determined by the following equation.
[0098]
ηrel = T / Ts
[Η] = (lnηrel) / C
DP = [η] / Km
here,
T: Number of seconds to drop the measurement sample
Ts: solvent dropping seconds
C: Concentration (g / l)
Km: 6 × 10^-Four
[0099]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this.
[0100]
The residual solvent amount of the film was measured as follows.
[0101]
The test film or web (U) is placed in a weighing bottle and weighed. Then, the film or web is heated at 150 ° C. for 3 hours, then cooled to room temperature and weighed so as not to absorb moisture. As the weight (D) of the absolutely dry film or web,
Residual solvent amount (%) = {(UD) / D} × 100
I asked for it.
[0102]
Transparency and stability over time for the dope in the examples, and viscosity of the dope, and for the film, haze, tear strength, tensile strength, elastic modulus, and folding resistance are measured and evaluated by the following methods. I went there. In addition, a film means the dried film cut out after winding up by the winding process of the last stage of a cellulose acylate film manufacturing process here.
[0103]
<Transparency of dope and stability over time>
Put the dope (cellulose acylate solution) in a transparent container and visually observe the transparency immediately after production, 72 hours and 168 hours later, and at the same time, observe the change in fluidity of the solution by turning the container upside down. It was evaluated and ranked according to the criteria.
[0104]
A: Transparent and uniform dope. The dope moved smoothly when the container was inverted.
B: Although it is slightly turbid, it is transparent. If the container is turned upside down, it has fluidity, but the moving interface is slightly crushed.
C: There is turbidity, insoluble matter is observed, and the dope moves unevenly when the container is turned upside down
D: Remarkably turbid, a lot of insoluble matter, phase-separated, or even if the container is turned upside down, it is not fluid and gelled.
[0105]
<Haze>
According to JIS K-6714, it measured using the haze meter (1001DP type, Nippon Denshoku Industries Co., Ltd. product).
[0106]
<Tear strength>
The film was conditioned for 4 hours in a room conditioned at a temperature of 23 ° C. and a relative humidity of 55% RH, cut into a sample size of 50 mm × 64 mm, and measured according to ISO 6383 / 2-1983.
[0107]
<Tensile strength and elastic modulus>
The film was conditioned at a temperature of 23 ° C. and a relative humidity of 55% RH for 4 hours, then cut to a sample width of 10 mm and a length of 200 mm, a distance between chucks of 100 mm, and a tensile test at a pulling speed of 100 mm / min. And asked.
[0108]
<Folding resistance>
The film was conditioned for 4 hours in a room conditioned at a temperature of 23 ° C. and a relative humidity of 55% RH, then cut into a sample length of 120 mm, and the number of folds until it was cut by bending in accordance with ISO 8776 / 2-1988 was measured. did.
[0109]
Example 1
Using a mixing kettle as shown in FIG. 1, 100 parts by weight of cellulose triacetate having an acetyl group substitution degree of 2.90 and a viscosity average polymerization degree of 300 at 30 ° C. was previously cooled to −80 ° C. in the mixing kettle. The mixture was gradually added to 500 parts by weight of a mixed organic solvent composed of methyl acetate and acetone (mixing weight ratio 7: 3) with stirring. Twenty minutes after the completion of the charging, all the cellulose triacetate was swollen, and the obtained swollen mixture was transferred to a dissolving kettle. The swollen mixture in the dissolution kettle was heated to 50 ° C. to prepare a cellulose triacetate concentration of 20% by weight. Further, 10 parts by weight of triphenyl phosphate was added. When stirring was continued for 40 minutes, the swollen mixture dissolved and a transparent dope was obtained. The dope was allowed to stand at 30 ° C. overnight and subjected to a defoaming operation, and then the dope was manufactured by Azumi Filter Paper No. 1 manufactured by Azumi Filter Paper Co., Ltd. It filtered using 244 and used for film forming. The obtained dope was fed to the die by a quantitative gear pump and cast onto a stainless steel belt running endless so that the film thickness after drying was 120 μm. The first half was dried on a temperature-controlled belt by contacting hot water at 50 ° C. from the back side, and the web was dried by applying 90 ° C. drying air in the second half. When the belt makes one round, the web is peeled off from the belt, and the both ends of the web are dried at 120 ° C. for 5 minutes while being held with clips, and then dried at 140 ° C. for 20 minutes while being transported by a roll. A triacetate film was obtained. The amount of residual solvent in the film was 0.8%.
[0110]
Example 2
Using a mixing kettle with a stainless steel mesh having a mesh opening size of 5 mm as shown in FIG. 2, the acetyl group substitution degree was 2.71 at 30 ° C., the propionyl group substitution degree was 0.17, and the viscosity average polymerization degree was 350. While stirring 100 parts by weight of cellulose acetate propionate in 900 parts by weight of a mixed organic solvent (mixing weight ratio 7: 3) consisting of methyl acetate and acetone previously cooled to -70 ° C. in a mixing kettle while gradually stirring. I put it in. 20 minutes after the completion of the charging, all of the cellulose acetate propionate swelled. The organic solvent which did not participate in the swelling was discharged through the mesh, and the swollen mixture was transferred to the dissolving kettle. The dissolution vessel is heated to 50 ° C., and a mixed organic solvent of methyl acetate and acetone (weight ratio 7: 3) heated to 50 ° C. is added so that the concentration of cellulose acetate propionate is 20% by weight. Prepared. Further, 10 parts by weight of triphenyl phosphate was added. When stirring was continued for 20 minutes, the swollen mixture dissolved and became a transparent dope. The dope was allowed to stand at 30 ° C. overnight and subjected to a defoaming operation, and then the dope was manufactured by Azumi Filter Paper No. 1 manufactured by Azumi Filter Paper Co., Ltd. It filtered using 244 and used for film forming. A film was formed in the same manner as in Example 1 to obtain a 120 μm cellulose acetate propionate film. The amount of residual solvent in the film was 0.9%.
[0111]
Example 3
The test was conducted using the mixing kettle of FIG. 2 and the melting kettle of FIG. Using a mixing kettle with a stainless steel mesh having a mesh opening size of 5 mm as shown in FIG. 2, the acetyl group substitution degree was 2.71 at 30 ° C., the propionyl group substitution degree was 0.17, and the viscosity average polymerization degree was 350. While stirring 100 parts by weight of cellulose acetate propionate in 1000 parts by weight of a mixed organic solvent consisting of methyl acetate and acetone (mixing weight ratio 7: 3) that had been cooled to -70 ° C. in a mixing kettle in advance. I put it in. 20 minutes after the completion of the charging, all of the cellulose acetate propionate swelled. The organic solvent which did not participate in the swelling was discharged through 600 parts by weight of the mesh, and the resulting swollen mixture was transferred to a dissolving kettle. The swollen mixture was added to 200 parts by weight of the same organic solvent that had been heated to 50 ° C. in advance in the dissolution vessel of FIG. 3, and the temperature was kept at 50 ° C. and dissolved while stirring. It dissolved completely within 20 minutes. Using the prepared dope, a 120 μm cellulose acetate propionate film was obtained by the solution casting film forming method in the same manner as in Example 1. The residual solvent amount was 0.9%.
[0112]
Example 4
It tested using the continuous mixer of FIG. 4 and FIG. 5, and an organic-solvent separator. As shown in FIG. 4, cellulose acetate propionate having a substitution degree of acetyl group of 2.71 at 30 ° C., a substitution degree of propionyl group of 0.17, and a viscosity average polymerization degree of 350 was transferred in advance to −70 ° C. Were successively added to a mixed organic solvent composed of methyl acetate and acetone (weight ratio 7: 3). The rate of charging was adjusted to 5% by weight with respect to the flow rate of the mixed solvent per unit time. Five minutes after the addition, all cellulose acetate propionate swelled at the end of the mixer. The charging was completed with 10 powders. Accordingly, the swelling time required 15 minutes. Next, the swollen mixture is introduced into an organic solvent separator equipped with a stainless steel mesh having a mesh opening of 1 mm, and the mixture being transferred is concentrated while separating the excess organic solvent that was not involved in the swelling. The mixed mixture was transferred to a melting kettle. The separated organic solvent recovered 60% by weight of the amount used. The concentrated mixture was continuously charged into an organic solvent having the same composition as that previously heated to 50 ° C. in the dissolution vessel. The concentrated mixture dissolved immediately upon contact with an organic solvent at 50 ° C. and became a transparent dope. It took 10 minutes to finish charging all the concentrated mixture. Using this dope, a 120 μm cellulose acetate propionate film was obtained by the solution casting film forming method in the same manner as in Example 1. The residual solvent amount was 0.9%.
[0113]
Example 5
The test was conducted using the continuous mixer, continuous organic solvent separator and continuous dissolver shown in FIG. Cellulose acetate propionate having a substitution degree of acetyl group of 2.71 at 30 ° C., a substitution degree of propionyl group of 0.17, and a viscosity average polymerization degree of 350, consisting of methyl acetate and acetone in the transfer previously cooled to −70 ° C. It poured into the mixed organic solvent (weight ratio 7: 3) one after another. The rate of charging was adjusted to 5% by weight with respect to the flow rate of the mixed solvent per unit time. Five minutes after the addition, all cellulose acetate propionate swelled at the end of the mixer. The input was completed in 10 minutes. Accordingly, the swelling time required 15 minutes. Next, the swollen mixture was introduced into a separator equipped with a stainless steel mesh having an opening of 1 mm, and the mixture being transferred was concentrated and transferred to the dissolving step while separating excess organic solvent that was not involved in the swelling. . The concentration of cellulose acetate propionate relative to the concentrated mixture was 40% by weight. A mixed organic solvent of methyl acetate and acetone (weight ratio 7: 3) that had been heated to 50 ° C. in advance was flowing through the dissolver, and the concentrated mixture was charged therein. The charging ratio of the concentrated mixture to the dissolver to the heated organic solvent was 1: 1. The concentrated mixture immediately started to dissolve, and a 20 wt% cellulose acetate propionate solution (dope) was obtained and introduced into a storage kettle. It took 10 minutes to finish adding all the concentrated mixture. Here, a small amount of an organic solvent (same ratio) was added to the storage kettle so that triphenyl phosphate was 10% by weight with respect to cellulose acylate, and dissolved while stirring. Using this dope, a film was formed by the solution casting film forming method in the same manner as in Example 1 to obtain a 120 μm cellulose acetate propionate film. The amount of residual solvent in the film was 0.9%.
[0114]
Example 6
A 120 μm cellulose acetate propionate film was obtained in the same manner as in Example 2 except that the organic solvent was changed to methyl acetate and ethanol (95: 5). The amount of residual solvent was 1.0%.
[0115]
Example 7
Except for using cellulose triacetate having an acetyl group substitution degree of 2.88 and a viscosity average polymerization degree of 300, dissolution was carried out in the same manner as in Example 5 to form a film by the solution casting film forming method to obtain a 120 μm cellulose triacetate film. It was. The amount of residual solvent was 1.1%.
[0116]
Example 8
A dope was obtained in the same manner as in Example 1 except that the cellulose acetate propionate had an acetyl group substitution degree of 2.61, a propionyl group substitution degree of 0.3, and a viscosity average polymerization degree of 400. Further, a 120 μm cellulose acetate propionate film was obtained by a solution casting film forming method. The amount of residual solvent was 1.2%.
[0117]
Example 9
A dope was obtained in the same manner as in Example 3 except that the cellulose acetate propionate had an acetyl group substitution degree of 2.38, a propionyl group substitution degree of 0.39, and a viscosity average polymerization degree of 450. A 120 μm cellulose acetate propionate film was obtained by a solution casting method.
[0118]
Example 10
In Example 5, the separated organic solvent was discharged from the organic solvent outlet of the organic solvent separator, and sent to the filter by a pump. Azumi Filter Paper No. The dope was obtained by filtering using 10 pieces of 244, cooling again with a cooler, and using the reused organic solvent in a 1: 1 mixture with fresh organic solvent and dissolving continuously for 24 hours.
[0119]
Comparative Example 1
100 parts by weight of cellulose triacetate having an acetyl group substitution degree of 2.88 and a viscosity average polymerization degree of 300, 500 parts by weight of methyl acetate, and 10 parts by weight of triphenyl phosphate are mixed at room temperature, and then mixed in a mixing kettle jacket with stirring. -70 ° C refrigerant was introduced and cooled for 30 minutes, the jacket refrigerant was removed, 50 ° C hot water was introduced into the jacket, the temperature was maintained for 30 minutes, the hot water was removed, and the dissolved state of the mixture was observed. Since the dissolution was insufficient, the dope was prepared by repeating the treatment once more. Therefore, it took at least 120 minutes for the cellulose triacetate to dissolve. In the same manner as in Example 1, the dope bubbles were removed, and a 120 μm cellulose triacetate film was obtained by a solution casting film forming method. The residual solvent amount was 0.9%.
[0120]
Comparative Example 2
A 120 μm cellulose acetate propionate film was obtained in the same manner as in Comparative Example 1 except that the organic solvent was changed to 400 parts by weight of acetone, a substitution degree of acetyl group of 2.56, and a substitution degree of propionyl group of 0.35. The amount of residual solvent was 1.1%.
[0121]
The above test was conducted and the evaluation results are shown in Table 1.
[0122]
[Table 1]

[0123]
(Results) As is apparent from Table 1, the dissolution method of the present invention was able to significantly shorten the dissolution time as compared with the conventional cooling dissolution methods shown in Comparative Examples 1 and 2. In addition, the obtained dope has good transparency and stability over time, and the obtained cellulose acylate film has good haze and mechanical strength, and is suitable for silver halide photographic materials and liquid crystal image display devices. I had enough time to use it.
[0124]
Although not shown in the table, as a result of continuing to use the organic solvent separated from the mixture of Example 10 for dissolution for 24 hours, it was found that there was no problem with the transparency of the dope.
[0125]
【The invention's effect】
Greatly reduced the amount of chlorinated organic solvent used, or a method for preparing a cellulose acylate solution (dope) that is not used at all, and the transparency and mechanical strength of cellulose acylate film are excellent. It is useful for liquid crystal image display devices.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a mixing step.
FIG. 2 is a schematic cross-sectional view of a mixing process.
FIG. 3 is a schematic cross-sectional view of a melting process.
FIG. 4 is a schematic cross-sectional view of a continuous mixing step and a continuous organic solvent separation step.
FIG. 5 is a schematic cross-sectional view of a continuous mixing step, a continuous organic solvent separation step, and a dissolution step.
FIG. 6 is a schematic cross-sectional view of a continuous mixing step, a continuous organic solvent separation step, and a continuous dissolution step.
FIG. 7 is a schematic diagram of a process for circulating and using a separated organic solvent.
FIG. 8 is a schematic sectional view of a solution casting film forming apparatus.
[Explanation of symbols]
1 Organic solvent
2 Cooler
3 Mixing pot
4 Stirrer
5 Thermal jacket
6 Cellulose acylate
7 Silo
8 Cutting and feeding machine
9 Organic solvent inlet
10 Cellulose acylate inlet
11 Mixture outlet
12 Swollen mixture
13 Mixing pot
14 mesh
15 Stirrer
16 Cellulose acylate
17 Silo
18 Cutting and feeding machine
19 Organic solvent inlet
20 Cellulose acylate inlet
21 Mixture outlet
22 Organic solvent
23 Organic solvent outlet
24 Thermal jacket
25 Melting pot
26 Organic solvents
27 Stirrer
28 Heat exchanger (heater)
29 Mixture inlet
30 Organic solvent inlet
31 Mixture outlet
32 Thermal jacket
33 Mixer
34 Partition plate
35 Inline mixer
36 Cooler
37 Organic solvent inlet
38 Cellulose acylate
39 silo
40 Cutting powder feeder
41 Cellulose acylate inlet
42 Organic solvent separator
43 mesh
44 Mixture
45 Organic solvent
46 Mixture outlet
47 Organic solvent outlet
48 Thermal jacket
49 End point
50 Dissolving machine
51 Heat exchanger (heater)
52 Organic solvent inlet
53 Partition plate
54 Solution outlet
60 mixer
61 Organic solvent separator
62 Cooler
63 Organic solvent inlet
64 Cellulose acylate inlet
65 Mixture outlet
66 Mixture inlet
67 Mixture outlet
68 Organic solvent outlet
69 pump
70 filters
71 Support
72 Pressure die
73 Web
74 Peeling point
75 Tenter
76 Winder
77 Storage pot
78 Dope
79 Dope inlet
80 Additive inlet
81 Dope outlet
82 Gear pump
83 Thermal jacket
84 Drying equipment
85 rolls (roll group)

Claims (7)

A step of cooling a mixed organic solvent of either methyl acetate and acetone or methyl acetate and ethanol to −100 to −10 ° C., and cooling with cellulose acylate in which the hydroxyl group is substituted with an acyl group having 2 to 5 carbon atoms. A method for preparing a cellulose acylate solution, comprising: mixing an organic solvent; swelling a mixture; and heating and dissolving the swollen mixture. A step of cooling a mixed organic solvent of either methyl acetate and acetone or methyl acetate and ethanol to −100 to −10 ° C., and cooling with cellulose acylate in which the hydroxyl group is substituted with an acyl group having 2 to 5 carbon atoms. Cellulose comprising a step of mixing the organic solvent, a step of swelling the mixture, a step of separating and concentrating a part of the organic solvent from the swollen mixture by a separating means, and a step of dissolving the concentrated mixture by heating. Preparation method of acylate solution. A step of cooling a mixed organic solvent of either methyl acetate and acetone or methyl acetate and ethanol to −100 to −10 ° C., and cooling with cellulose acylate in which the hydroxyl group is substituted with an acyl group having 2 to 5 carbon atoms. A step of mixing the organic solvent, a step of swelling the mixture, a step of mixing the organic solvent having the same composition as described above adjusted to 0 to 120 ° C. and the swollen mixture to form a solution. Preparation method of rate solution. Cellulose acylate in which a hydroxyl group is substituted with an acyl group having 2 to 5 carbon atoms is continuously added to a mixed organic solvent of methyl acetate and acetone or methyl acetate and ethanol being transferred at -100 to -10 ° C. A cellulose acylate solution comprising: a step of swelling a mixture formed by adding to a solution; a step of separating and concentrating an organic solvent from the swollen mixture by separation means; and a step of dissolving the mixture after heating by heating. Preparation method. Cellulose acylate in which a hydroxyl group is substituted with an acyl group having 2 to 5 carbon atoms is continuously added to a mixed organic solvent of methyl acetate and acetone or methyl acetate and ethanol being transferred at -100 to -10 ° C. A step of swelling the mixture formed by adding to the step, a step of separating and concentrating a part of the organic solvent from the swollen mixture by a separating means, and an organic solvent having the same composition as above at 0 to 120 ° C. A method for preparing a cellulose acylate solution, comprising a step of mixing the components to form a solution. Cellulose acylate in which a hydroxyl group is substituted with an acyl group having 2 to 5 carbon atoms is continuously added to a mixed organic solvent of methyl acetate and acetone or methyl acetate and ethanol being transferred at -100 to -10 ° C. The step of swelling the mixture formed by adding to the step, the step of separating and concentrating a part of the organic solvent from the swollen mixture by a separating means, and the same composition as above while transferring the concentrated mixture at 0 to 120 ° C. A method for preparing a cellulose acylate solution, comprising the step of mixing the organic solvent and forming a solution. A cellulose characterized by preparing a cellulose acylate solution by the method for preparing a cellulose acylate solution according to any one of claims 1 to 6, and performing solution casting film formation using the cellulose acylate solution. A method for producing an acylate film.

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