JP4357966B2 - Process for producing aromatic polymer - Google Patents

Description

（ここで、Ａｒ^１およびＡｒ^５はフェニレン又はナフタレン、Ａｒ^２はフェニレン、ナフタレン、またはメタもしくはパラ位でつながるフェニレン数２以上の化合物残基、Ａｒ^３はフェニレン又はポリフェニレン、ナフタレン、またはメタもしくはパラ位でつながるフェニレン数２以上の化合物残基、Ａｒ^４はフェニレン、ナフタレン、またはメタもしくはパラ位でつながるフェニレン数２以上の化合物残基であり、Ａｒ^１〜Ａｒ^５の芳香族環の水素原子の一部が、低級アルキル、低級アルコキシ、ハロゲン、ニトロ、フェニル、フェノキシ基で置換されていてもよい。）
本発明の第７は、芳香族ポリマーが、下記一般式（Ｉ），（ＩＩ），（ＩＩＩ）及び（ＩＶ）で表される構成単位からなり、各構成単位の比率が構成単位（Ｉ）４０〜７５モル％、構成単位（ＩＩ）８．５〜３０モル％、構成単位（ＩＩＩ）８．５〜３０モル％、構成単位（ＩＶ）０．１〜８モル％（ここで、構成単位（Ｉ）〜（ＩＶ）の合計は１００モル％である。）であり、溶融時に光学的異方性を示す全芳香族ポリエステルであることを特徴とする本発明の第１〜６のいずれか１項に記載の芳香族ポリマーの製造方法を提供する。

（ここで、Ａｒ_１は２，６−ナフタレン、Ａｒ_２は１，２−フェニレン、１，３−フェニレン及び１，４−フェニレンから選ばれる少なくとも１種、Ａｒ_３は１，３−フェニレン、１，４−フェニレン、あるいはパラ位でつながるフェニレン数２以上の化合物の残基の少なくとも１種、Ａｒ_４は１，４−フェニレンである。）
本発明の第８は、芳香族ポリマーが全芳香族液晶ポリマーである本発明の第１〜６のいずれか１項に記載の芳香族ポリマーの製造方法を提供する。
本発明の第９は、原料として、フェノール性水酸基及び／又は芳香族アミノ基を有する芳香族化合物を使用する際に、フェノール性水酸基及び／又は芳香族アミノ基当量の１．０２〜１．０６倍量の炭素数１〜６のアシル化剤を添加して、フェノール性水酸基及び／又は芳香族アミノ基をアシル化させることを特徴とする本発明の第１〜６又は８に記載の芳香族ポリマーの製造方法を提供する。
発明を実施するための最良の形態
以下に本発明の実施の形態を説明する。
芳香族ポリマー
本発明で製造する芳香族ポリマーは、ポリマー用原料として、少なくとも下記一般式（ｉ）〜（ｖ）で表される構造を有する化合物のいずれか１以上を使用して得られる芳香族ポリエステル、または芳香族ポリエステルアミドである。

（ここで、Ａｒ^１およびＡｒ^５はフェニレン又はナフタレン、Ａｒ^２はフェニレン、ナフタレン、またはメタもしくはパラ位でつながるフェニレン数２以上の化合物残基、Ａｒ^３はフェニレン又はポリフェニレン、ナフタレン、またはメタもしくはパラ位でつながるフェニレン数２以上の化合物残基、Ａｒ^４はフェニレン、ナフタレン、またはメタもしくはパラ位でつながるフェニレン数２以上の化合物残基であり、Ａｒ^１〜Ａｒ^５の芳香族環の水素原子の一部が、低級アルキル、低級アルコキシ、ハロゲン、ニトロ、フェニル、フェノキシ基で置換されていてもよい。）
一般式（ｉ）で表される構造を有する化合物としては、芳香族ヒドロキシカルボン酸及びそのエステル誘導体、具体的には、４−ヒドロキシ安息香酸、３−ヒドロキシ安息香酸、６−ヒドロキシ−２−ナフトエ酸、６−ヒドロキシ−１−ナフトエ酸等の芳香族ヒドロキシカルボン酸；３−メチル−４−ヒドロキシ安息香酸、３，５−ジメチル−４−ヒドロキシ安息香酸、２，６−ジメチル−４−ヒドロキシ安息香酸、６−ヒドロキシ−５−メチル−２−ナフトエ酸等の芳香族ヒドロキシカルボン酸のアルキル置換体；３−メトキシ−４−ヒドロキシ安息香酸、３，５−ジメトキシ−４−ヒドロキシ安息香酸、６−ヒドロキシ−５−メトキシ−２−ナフトエ酸等の芳香族ヒドロキシカルボン酸のアルコキシ置換体；及び３−クロロ−４−ヒドロキシ安息香酸、２−クロロ−４−ヒドロキシ安息香酸、２，３−ジクロロ−４−ヒドロキシ安息香酸、３，５−ジクロロ−４−ヒドロキシ安息香酸、２，５−ジクロロ−４−ヒドロキシ安息香酸、３−ブロモ−４−ヒドロキシ安息香酸、６−ヒドロキシ−５−クロロ−２−ナフトエ酸、６−ヒドロキシ−７−クロロ−２−ナフトエ酸、６−ヒドロキシ−５，７−ジクロロ−２−ナフトエ酸等の芳香族ヒドロキシカルボン酸のハロゲン置換体等が挙げられる。これら芳香族ヒドロキシカルボン酸のエステル誘導体としては、アセチル、プロピオニル等のアシル誘導体が挙げられる。
一般式（ｉｉ）で表される構造を有する化合物としては、芳香族ジカルボン酸及びその誘導体、具体的にはテレフタル酸、４，４’−ジフェニルジカルボン酸、４，４’−トリフェニルジカルボン酸、２，６−ナフタレンジカルボン酸、ジフェニルエーテル−４，４’−ジカルボン酸、ジフェノキシエタン−４，４’−ジカルボン酸、ジフェノキシブタン−４，４’−ジカルボン酸、ジフェニルエタン−４，４’−ジカルボン酸、イソフタル酸、ジフェニルエーテル−３，３’−ジカルボン酸、ジフェノキシエタン−３，３’−ジカルボン酸、ジフェノキシエタン−３，３’−ジカルボン酸、ジフェニルエタン−３，３’−ジカルボン酸、ナフタレン−２，６−ジカルボン酸の如き芳香族ジカルボン酸；クロロテレフタル酸、ジクロロテレフタル酸、ブロモテレフタル酸等の上記芳香族ジカルボン酸のハロゲン置換体；メチルテレフタル酸、ジメチルテレフタル酸、エチルテレフタル酸等の上記芳香族ジカルボン酸のアルキル置換体；及びメトキシテレフタル酸、エトキシテレフタル酸等の上記芳香族ジカルボン酸のアルコキシ置換体等が挙げられる。
一般式（ｉｉｉ）で表される構造を有する化合物としては、芳香族ジオール及びそのエステル誘導体、具体的にはハイドロキノン、レゾルシン、４，４’−ジヒドロキシジフェニル、４，４’−ジヒドロキシトリフェニル、２，６−ナフタレンジオール、４，４’−ジヒドロキシジフェニルエーテル、ビス（４−ヒドロキシフェノキシ）エタン、３，３’−ジヒドロキシジフェニル、３，３’−ジヒドロキシジフェニルエーテル、１，４−、１，５−、もしくは２，６−ナフタレンジオール、２，２−ビス（４−ヒドロキシフェニル）プロパン、２，２−ビス（４−ヒドロキシフェニル）エタン等の芳香族ジオール；及びクロロハイドロキノン、メチルハイドロキノン、ブチルハイドロキノン、フェニルハイドロキノン、メトキシハイドロキノン、フェノキシハイドロキノン、４−クロルレゾルシン、４−メチルレゾルシン等の上記芳香族ジオールのアルキル、アルコキシまたはハロゲン置換体が挙げられる。
一般式（ｉｖ）で表される構造を有する化合物としては、芳香族ヒドロキシアミン及びそのアミド誘導体、具体的には４−アミノフェノール、３−アミノフェノール、３−メチル−４−アミノフェノール、２−クロロ−４−アミノフェノール、４−アミノ−１−ナフトール、４−アミノ−４’−ヒドロキシジフェニル、４−アミノ−４’−ヒドロキシジフェニルエーテル、４−アミノ−４’−ヒドロキシジフェニルメタン、４−アミノ−４’−ヒドロキシジフェニルスルフィドなどが挙げられる。これら芳香族ヒドロキシアミンのエステル誘導体及び／又はアミド誘導体としては、４−アセトアミドフェノールのようなアセチル、プロピオニル等の誘導体が挙げられる。
一般式（ｖ）で表される構造を有する化合物としては、芳香族アミノカルボン酸及びそのアミド誘導体、具体的には、４−アミノ安息香酸、３−アミノ安息香酸、６−アミノ−２−ナフトエ酸、６−アミノ−１−ナフトエ酸等の芳香族アミノカルボン酸；３−メチル−４−アミノ安息香酸、３，５−ジメチル−４−アミノ安息香酸、２，６−ジメチル−４−アミノ安息香酸、６−アミノ−５−メチル−２−ナフトエ酸等の芳香族アミノカルボン酸のアルキル置換体；３−メトキシ−４−アミノ安息香酸、３，５−ジメトキシ−４−アミノ安息香酸、６−アミノ−５−メトキシ−２−ナフトエ酸等の芳香族アミノカルボン酸のアルコキシ置換体；及び３−クロロ−４−アミノ安息香酸、２−クロロ−４−アミノ安息香酸、２，３−ジクロロ−４−アミノ安息香酸、３，５−ジクロロ−４−アミノ安息香酸、２，５−ジクロロ−４−アミノ安息香酸、３−ブロモ−４−アミノ安息香酸、６−アミノ−５−クロロ−２−ナフトエ酸、６−アミノ−７−クロロ−２−ナフトエ酸、６−アミノ−５，７−ジクロロ−２−ナフトエ酸等の芳香族アミノカルボン酸のハロゲン置換体等が挙げられる。これら芳香族アミノカルボン酸のアミド誘導体としては、４−アセトアミド安息香酸のようなアセチル、プロピオニル等の誘導体が挙げられる。
上記芳香族ポリエステルは、好ましくは溶融時に異方性を示す液晶ポリエステルであり、特に好ましくは全芳香族液晶ポリエステルである。
全芳香族液晶ポリエステルとしては、例えば、下記一般式（Ｉ），（ＩＩ），（ＩＩＩ）及び（ＩＶ）で表される構成単位からなり、各構成単位の比率が構成単位（Ｉ）４０〜７５モル％、構成単位（ＩＩ）８．５〜３０モル％、構成単位（ＩＩＩ）８．５〜３０モル％、構成単位（ＩＶ）０．１〜８モル％（ここで、構成単位（Ｉ）〜（ＩＶ）の合計は１００モル％である。）であるポリエステルが挙げられる。

（ここで、Ａｒ_１は２，６−ナフタレン、Ａｒ_２は１，２−フェニレン、１，３−フェニレン及び１，４−フェニレンから選ばれる少なくとも１種、Ａｒ_３は１，３−フェニレン、１，４−フェニレン、あるいはパラ位でつながるフェニレン数２以上の化合物の残基の少なくとも１種、Ａｒ_４は１，４−フェニレンである。）
具体的には、各構成単位を表す原料としては、例えば（Ｉ）を与えるものとして２−ヒドロキシ−６−ナフトエ酸、（ＩＩ）を与えるものとして前記芳香族ジオール成分、（ＩＩＩ）を与えるものとして前記芳香族ジカルボン酸成分、（ＩＶ）を与えるものとして４−ヒドロキシ安息香酸を組み合わせた溶融異方性を示すポリエステルが挙げられ、中でも上記（Ｉ），（ＩＩ），（ＩＩＩ）および（ＩＶ）の構造単位が上記組成からなる液晶ポリエステルを製造する際に、重合反応中に昇華物が多いため、本発明の製造方法は、顕著にその効果を発揮する。
重合装置
本発明において使用する重合装置は、バッチ式重合装置であり、１段で重縮合を行うように１基の反応槽を有する装置でもよいが、２段以上の重縮合を行うための２槽以上の反応槽を有する装置が好ましい。この場合、１段目はアシル化に、２段目以降は重縮合に使用される。
重縮合が行われる重合装置としては、原料供給口とポリマー排出口を有する反応槽、該反応槽に設けられた撹拌装置、留出管、反応温度管理装置及び反応圧力管理装置からなる。
温度管理装置としては、後述するジャケットまたはヒーターが挙げられる。
本発明では、反応空間に接する反応装置部分、即ち反応装置上部部分を冷却する必要があるので、反応装置の上部と下部の加熱手段（ジャケットやヒータ）を分けて設けることが好ましい。温度制御の観点から、好ましくはジャケットが使用され、所定の温度に冷却させるように外部の熱交換器を介して熱媒を循環させる。
圧力管理装置としては、真空ポンプ、エジェクタなどと圧力測定のための圧力計が挙げられる。
留出管は、後述する還流器（コンデンサー）及び反応槽内に突出したノズルからなるものが好ましく挙げられるが、必ずしも反応槽内に突出していなくてもよい。
以下、本発明に使用する製造装置の一例を第１図に示した。以下、第１図に従って説明する。第１図において、１はアシル化反応槽、２は原料供給ライン、３は還流器、４は留出液捕集器へのライン、５は撹拌器、６は加熱手段、７はアシル化反応物排出口、８はアシル化反応物移槽ライン、９は吸引ライン、１０は生成ポリマー排出口、１１は生成ポリマー排出ライン、１２は重縮合反応槽、Ａは反応槽内に突出した留出管の下端部（ノズル）である。
ライン２からは原料芳香族化合物とアシル化剤が供給される。これらはモノマー種毎に別々の供給ラインから供給されてもよい。
通常、１段目のアシル化反応槽（予備反応槽ということもある）においてアシル化が行われる。アシル化剤と共に供給される１種または２種以上のヒドロキシル基含有芳香族化合物は、アシル化反応によりエステル誘導体とされる。このようなアシル化反応を受けるのは、原料のヒドロキシル基含有芳香族化合物であるが、アミノ基含有化合物もアシル化される。本発明においては、ほとんどのヒドロキシル基含有化合物をアシル化反応槽でアシル化して重縮合反応槽１２に供給することが好ましい。
なお、別の方法として反応槽１を設けず反応槽１２内で、重縮合に先立ち、アシル化反応物を製造することもできる。
アシル化剤としては、通常酸無水物が使用され、酸無水物としては炭素数１〜６の一価カルボン酸の無水物、具体的には無水酢酸、無水プロピオン酸、無水酪酸等が例示され、好ましくは無水酢酸が使用される。アシル化反応は、アシル化反応槽に取り付けられた還流ラインにより副生する酢酸等の脂肪酸を除去しながら進行させる。反応槽１２に供給されるアシル化されたヒドロキシル基含有芳香族化合物等は一部または全部がオリゴマーとなっていてもよい。
なお反応槽１２には、通常、図示しないラインから触媒が供給される。触媒としては、一般のポリエステル樹脂の製造に使用されている公知触媒、例えば酸化ゲルマニウム等のゲルマニウム化合物、シュウ酸第一スズ，酢酸第一スズ，ジアルキルスズ酸化物，ジアリールスズ酸化物等のスズ化合物、二酸化チタン，チタンアルコキシド類，アルコキシチタンケイ酸塩のようなチタン化合物、酢酸ナトリウム，酢酸カリウム，酢酸カルシウム，酢酸亜鉛，酢酸第一鉄のような有機酸の金属塩等を挙げることができる。触媒の量は、生成ポリマーに対して金属重量部基準で１０〜１００ｐｐｍ、好ましくは２０〜８０ｐｐｍである。
反応槽１２においては、撹拌器５で反応混合物を撹拌し、また熱媒を用いるジャケットまたはヒーターのような加熱手段６により外部から加熱し、発生する酢酸等の脂肪酸をライン９から留去しながら重縮合が進行する。その際、エステル化合物等の高価なモノマーが脂肪酸と共に留去されるので還流器３を設け、脂肪酸と共に還流液を反応混合物へ戻す。
本発明においては、前記還流液を反応槽内壁を伝わせることなく反応混合物中に落下させることができる。これには還流器３に反応槽１２内に突出したノズルＡを設置することが好ましい。ノズルＡの突出長さは、還流液が反応槽１２の内壁に伝わらない程度であればよい。
重縮合は脂肪酸の留出により進行するが、最終段階では吸引ライン９から反応槽１２内を減圧にし、揮発成分としての脂肪酸を除去する。重縮合が終了すると、得られた溶融状態の液晶性ポリマーは、反応槽１２の下部に設けられた排出口１０および排出ライン１１を経由して反応槽外に取り出される。
反応条件
反応槽を１基で行う場合は、通常、原料モノマーを投入して窒素雰囲気下で１４０〜２００℃程度となるまで昇温し、昇温と同時に撹拌を開始し、スラリー化した原料モノマーを、アシル化反応によって生成した留出物および未反応のアシル化剤を留出させながらアシル化反応を行った後、３００〜４００℃まで昇温し、減圧もしくは真空下で重縮合する。
第１図のように、反応槽を２基以上使って行われる場合、通常、反応槽１に原料モノマーとアシル化剤を仕込み、撹拌しながらスラリー化後昇温して１３０〜２００℃で、アシル化により生成する留出物および未反応のアシル化剤を留出させながら、１〜２時間アシル化する。次に真空発生装置のついた反応槽１２に移して、さらに３００〜４００℃程度の最終反応温度になるまで昇温して、減圧または真空下で重縮合する。なお、最終反応温度とは、重縮合反応時の反応液の最終到達温度である。
本発明において重要な点は、重縮合時に反応混合物からのモノマーもしくはオリゴマーなどの反応混合物が反応槽壁、留出管の還流器や留出液凝集コンデンサーノズルなどに付着乾燥し、それが加熱乾燥されることにより分解反応や着色などの所望しない反応が生ずることを抑制しながら重縮合する点にある。
従って、本発明では下記の条件で反応を行うことが重要である。
▲１▼反応混合物が付着する部分、即ち、重縮合反応時に反応液面より上の反応空間に接する反応装置部分、具体的には反応槽の上蓋や、留出液凝集コンデンサー入り口部分の温度を、１５０〜３００℃にコントロールする。仮に昇華物が反応槽に付着しても、反応留出液蒸気が槽内に充満することにより反応槽内側を洗浄しながら重縮合を行うことができ、この温度範囲であれば昇華物は過度の熱履歴を受けることなくポリマーの融点程度の温度で溶融可能である。１５０℃未満に設定した場合、反応槽の設定温度との差から保温が十分できないことにより熱が逃げてしまい、反応槽の温度が下がってしまう。また、３００℃超にした場合には昇華物が熱履歴を受け、溶融しない物質へと変化してしまい留出管閉塞やポリマーへの混入といった問題も引き起こす危険がある。より好ましくは、下記▲２▼〜▲４▼を満足する条件で反応を行う。
▲２▼減圧重縮合時の真空度を２５〜２００Ｔｏｒｒの範囲にコントロールする。真空度を２５Ｔｏｒｒ未満にして重縮合を行った場合、減圧中の昇華物発生が多く、留出管閉塞の原因となる。また真空度が２００Ｔｏｒｒよりも高い場合、昇華物は少ないものの重縮合反応が非常に遅くなるといった問題がある。
▲３▼反応温度としては１４０〜４００℃であり、２．０℃／分以下、好ましくは１．０℃／分以下で昇温を行うが、原料の昇華を抑制するには、２８０℃以上、最終到達温度までの昇温速度を、１℃／分以下、好ましくは０．５℃／分以下にする。
▲４▼原料のフェノール性水酸基もしくはアミノ基を有する芳香族化合物の水酸基当量もしくはアミノ基当量に相当する量の１．０２〜１．０６倍量のアシル化剤を添加してアシル化させる。アシル化剤が１．０２倍未満の場合、アシル化反応が十分に進行せず、１．０６倍よりも多い場合はアシル化反応の他に架橋反応等の予期しない反応が起ることがある。
なお、反応槽上蓋、留出管等の温度を１５０〜３００℃にコントロールする手段としては、バンドヒーター、温度調節された熱媒の流通するジャケット等の加熱手段が挙げられる。
実施例
以下、実施例により本発明を更に具体的に説明するが、本発明はこれらの実施例によって限定されるものでない。
［実施例１］
中心軸のないパドル翼を有した内容積６Ｌの反応槽１と、中心軸のないダブルヘリカル翼を有した内容積６Ｌの反応槽２を用い、以下のように反応を行なった。
反応槽１に（Ｉ）を与える原料として２−ヒドロキシ−６−ナフトエ酸１２１８ｇ，（ＩＩ）を与える原料としてテレフタル酸５６０ｇ、（ＩＩＩ）を与える原料として４，４’−ジヒドロキシジフェニル６２８ｇ，（ＩＶ）を与える原料として４−ヒドロキシ安息香酸３７ｇ、および無水酢酸１４３２ｇ（ヒドロキシル基の１．０４当量倍）を仕込んだ。槽内を７０〜１５０ｒｐｍで撹拌し、１４０℃到達後、１４０℃で２時間反応後、２００℃まで昇温した。２００℃到達後、反応槽２に反応液を移行し７０ｒｐｍで撹拌を行い、さらに反応槽液温を３６０℃まで昇温した。反応槽２の上部の温度は槽内の反応物の温度を超えないよう所定の２００℃に設定した。反応槽液温が２８０℃から３６０℃までの昇温レートは０．５℃／ｍｉｎで行った。最終反応温度に達した後、常圧から約４０分かけ最終減圧度の７５Ｔｏｒｒまで減圧を行った。
重縮合反応終了後、反応槽１２内を約２ｋｇ／ｃｍ^２程度まで加圧し、ポリマーをストランド状に吐出して、冷却後カットしてペレットにした。運転条件は表１に記載の条件で行った。
結果を表１に示す。なお、○はバッチ式連続重合が可能、△は数回のバッチ式連続重合が可能、×はバッチ式連続重合が不可を示す。
［実施例２〜４及び比較例１〜３］
反応条件を表１に示すように変更した他は、実施例１と同様に行った。結果を表１に示す。

産業上の利用可能性
本発明によれば、原料芳香族化合物やオリゴマーが重合装置の空間部に付着して閉塞を生じたり、変色して品質を低下させることがなく、芳香族ポリマーをバッチ式連続重合により製造することができる。
【図面の簡単な説明】
第１図は、この発明にかかる芳香族ポリマーの製造方法で使用する重合装置の一例を示す図である。Technical field
The present invention relates to a process for producing aromatic polymers, particularly wholly aromatic liquid crystal polymers. More specifically, using an aromatic compound as a raw material, the temperature is raised to a final reaction temperature at a specific rate, and after reaching the final reaction temperature, an aromatic polymer that performs polycondensation at a specific pressure in the reaction system It relates to the manufacturing method.
According to the present invention, batch polymerization can be repeated without washing the polymerization apparatus.
Background art
In recent years, there has been an increasing demand for higher performance of plastics, and many polymers having various new capabilities have been developed and put on the market. Among them, an optically anisotropic liquid crystal polymer characterized by a parallel arrangement of molecular chains has attracted attention because it has excellent fluidity, mechanical properties, and physical properties.
As a method for producing a liquid crystal polymer, it is known to use a polymerization reaction apparatus in which a raw material is charged into an acylation reaction tank, an acylation reaction is performed, and then the polymerization reaction tank is transferred to perform a polycondensation reaction.
When the polymerization is carried out in a batch mode, clogging of the distillation pipe of the polymerization apparatus due to the sublimate tends to occur. If clogging occurs during the polymerization reaction, the internal pressure of the reactor rises and is very dangerous. In particular, in the case of batch-type continuous polymerization (repeating batch-type polymerization without washing the polymerization apparatus, also referred to as batch-on-batch polymerization), the problem of clogging appears remarkably. Also, the sublimate remains and receives a heat history, and becomes a foreign material that is higher than the melting point of normal polymer. After the polymerization is completed, it is mixed into the polymer when discharged from the reaction apparatus, thus adversely affecting the resulting polymer. Sometimes. Therefore, in order to perform batch continuous polymerization, the inside of the reactor must be periodically cleaned.
For this reason, JP-A-5-271398 proposes that the entrained raw material can be stably returned to the reaction vessel by refluxing a part of the distilled fatty acid to the reactor. Has been made. However, in this technique, when the reflux liquid flows down the inner wall of the reaction tank heated by the surrounding heat medium jacket or electric heater and returns to the reaction mixture, the reflux medium flows while flowing down the inner wall. The fatty acid evaporates due to the heat from the heater, and the raw material contained in the reflux liquid deposits and accumulates on the inner wall or the like, where it may be polycondensed, deteriorated, or carbonized and fall into the polymer.
An object of this invention is to provide the manufacturing method which enables manufacture of a high quality aromatic polymer by batch type continuous polymerization.
Disclosure of the invention
The inventors of the present invention use an aromatic compound as a raw material, raise the temperature to the final reaction temperature at a rate of 0.5 ° C./min or less, and reach the final reaction temperature, and then the reaction system reaches 25 to 200 Torr. The polycondensation reaction is carried out under reduced pressure, and the temperature of the reactor part in contact with the reaction space during the reaction is maintained at 150 to 300 ° C., so that the raw material aromatic compounds and the like adhere to the space part of the polymerization apparatus and cause clogging. The present inventors have found that an aromatic polymer can be produced by batch-type continuous polymerization without causing discoloration and deterioration in quality, and the present invention has been completed.
That is, the first aspect of the present invention uses a reaction vessel having a raw material supply port and a polymer discharge port, a stirrer, a distillation pipe, a reaction temperature management device, and a reaction pressure management device to superimpose aromatic polymer raw materials. Provided is a method for producing an aromatic polymer, characterized in that the temperature of a reactor part in contact with the reaction space is maintained at 150 to 300 ° C. during the polycondensation reaction when the aromatic polymer is produced in a batch by condensation. .
In the second aspect of the present invention, (1) the final reaction temperature is in the range of 300 to 400 ° C., the temperature is increased from 280 ° C. to the final reaction temperature at 0.5 ° C./min or less, and (2) the final reaction temperature. The method for producing an aromatic polymer according to the first aspect of the present invention is characterized in that the polycondensation is performed by reducing the internal pressure of the reaction system to 25 to 200 Torr.
According to a third aspect of the present invention, there is provided the method for producing an aromatic polymer according to the first or second aspect of the present invention, wherein the distillation pipe has a refluxer and a nozzle protruding into the reaction tank.
4th of this invention provides the manufacturing method as described in 3rd of this invention whose temperature of a nozzle is 150-300 degreeC.
According to a fifth aspect of the present invention, there is provided the method for producing an aromatic polymer according to any one of the first to fourth aspects of the present invention, wherein the production is repeated batchwise without washing the polymerization apparatus. .
6th of this invention uses any 1 or more of the compounds which have at least the structure represented by the following general formula (i)-(v) as a polymer raw material, Any 1st of 5th of this invention A method for producing the aromatic polymer described in 1. is provided.

(Where Ar ¹ And Ar ⁵ Is phenylene or naphthalene, Ar ² Is phenylene, naphthalene, or a compound residue having two or more phenylenes linked in meta or para position, Ar ³ Is phenylene, polyphenylene, naphthalene, or a compound residue having two or more phenylenes connected at the meta or para position, Ar ⁴ Is phenylene, naphthalene, or a compound residue having two or more phenylenes connected at the meta or para position, and Ar ¹ ~ Ar ⁵ A part of hydrogen atoms of the aromatic ring may be substituted with lower alkyl, lower alkoxy, halogen, nitro, phenyl, phenoxy group. )
In the seventh aspect of the present invention, the aromatic polymer is composed of structural units represented by the following general formulas (I), (II), (III) and (IV), and the ratio of each structural unit is the structural unit (I). 40 to 75 mol%, structural unit (II) 8.5 to 30 mol%, structural unit (III) 8.5 to 30 mol%, structural unit (IV) 0.1 to 8 mol% (wherein the structural unit (The total of (I) to (IV) is 100 mol%.), And is a wholly aromatic polyester that exhibits optical anisotropy when melted. A method for producing the aromatic polymer according to item 1 is provided.

(Where Ar ₁ Is 2,6-naphthalene, Ar ₂ Is at least one selected from 1,2-phenylene, 1,3-phenylene and 1,4-phenylene, Ar ₃ Is at least one residue of 1,3-phenylene, 1,4-phenylene, or a compound having two or more phenylenes linked in the para position, Ar ₄ Is 1,4-phenylene. )
8th of this invention provides the manufacturing method of the aromatic polymer of any one of 1-6 of this invention whose aromatic polymer is a wholly aromatic liquid crystal polymer.
In the ninth aspect of the present invention, when an aromatic compound having a phenolic hydroxyl group and / or an aromatic amino group is used as a raw material, the equivalent of 1.02 to 1.06 of the phenolic hydroxyl group and / or aromatic amino group is used. The aromatic according to the first to sixth or eighth aspect of the present invention, wherein a double amount of an acylating agent having 1 to 6 carbon atoms is added to acylate a phenolic hydroxyl group and / or an aromatic amino group. A method for producing a polymer is provided.
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below.
Aromatic polymer
The aromatic polymer produced in the present invention is an aromatic polyester obtained by using at least one of compounds having a structure represented by the following general formulas (i) to (v) as a polymer raw material, or Aromatic polyester amide.

(Where Ar ¹ And Ar ⁵ Is phenylene or naphthalene, Ar ² Is phenylene, naphthalene, or a compound residue having two or more phenylenes linked in meta or para position, Ar ³ Is phenylene, polyphenylene, naphthalene, or a compound residue having two or more phenylenes connected at the meta or para position, Ar ⁴ Is phenylene, naphthalene, or a compound residue having two or more phenylenes connected at the meta or para position, and Ar ¹ ~ Ar ⁵ A part of hydrogen atoms of the aromatic ring may be substituted with lower alkyl, lower alkoxy, halogen, nitro, phenyl, phenoxy group. )
Examples of the compound having the structure represented by the general formula (i) include aromatic hydroxycarboxylic acids and ester derivatives thereof, such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, and 6-hydroxy-2-naphthoic acid. Acids, aromatic hydroxycarboxylic acids such as 6-hydroxy-1-naphthoic acid; 3-methyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid Acid, alkyl-substituted products of aromatic hydroxycarboxylic acids such as 6-hydroxy-5-methyl-2-naphthoic acid; 3-methoxy-4-hydroxybenzoic acid, 3,5-dimethoxy-4-hydroxybenzoic acid, 6- Alkoxy-substituted aromatic hydroxycarboxylic acids such as hydroxy-5-methoxy-2-naphthoic acid; and 3-chloro-4-hydro Cibenzoic acid, 2-chloro-4-hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid, 3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy-7-chloro-2-naphthoic acid, 6-hydroxy-5,7-dichloro-2-naphthoic acid And halogen-substituted products of aromatic hydroxycarboxylic acids such as Examples of ester derivatives of these aromatic hydroxycarboxylic acids include acyl derivatives such as acetyl and propionyl.
Examples of the compound having the structure represented by the general formula (ii) include aromatic dicarboxylic acids and derivatives thereof, specifically terephthalic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-triphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid, diphenoxyethane-4,4′-dicarboxylic acid, diphenoxybutane-4,4′-dicarboxylic acid, diphenylethane-4,4′- Dicarboxylic acid, isophthalic acid, diphenyl ether-3,3′-dicarboxylic acid, diphenoxyethane-3,3′-dicarboxylic acid, diphenoxyethane-3,3′-dicarboxylic acid, diphenylethane-3,3′-dicarboxylic acid , Aromatic dicarboxylic acids such as naphthalene-2,6-dicarboxylic acid; chloroterephthalic acid, dichloroterephthalic acid, bromo Halogen substituted products of the above aromatic dicarboxylic acids such as terephthalic acid; alkyl substituted products of the above aromatic dicarboxylic acids such as methyl terephthalic acid, dimethyl terephthalic acid and ethyl terephthalic acid; Examples include alkoxy-substituted products of dicarboxylic acids.
Examples of the compound having the structure represented by the general formula (iii) include aromatic diols and ester derivatives thereof, specifically hydroquinone, resorcin, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxytriphenyl, 2 , 6-Naphthalenediol, 4,4′-dihydroxydiphenyl ether, bis (4-hydroxyphenoxy) ethane, 3,3′-dihydroxydiphenyl, 3,3′-dihydroxydiphenyl ether, 1,4-, 1,5-, or Aromatic diols such as 2,6-naphthalenediol, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) ethane; and chlorohydroquinone, methylhydroquinone, butylhydroquinone, phenylhydroquinone , Methoxyhydroquinone, E Bruno carboxymethyl hydroquinone, 4-chloro resorcinol, the aromatic alkyl diols such as 4-methyl resorcin, alkoxy or halogen-substituted derivatives thereof.
Examples of the compound having the structure represented by the general formula (iv) include aromatic hydroxyamine and amide derivatives thereof, specifically 4-aminophenol, 3-aminophenol, 3-methyl-4-aminophenol, 2- Chloro-4-aminophenol, 4-amino-1-naphthol, 4-amino-4'-hydroxydiphenyl, 4-amino-4'-hydroxydiphenyl ether, 4-amino-4'-hydroxydiphenylmethane, 4-amino-4 Examples include '-hydroxydiphenyl sulfide. Examples of ester derivatives and / or amide derivatives of these aromatic hydroxyamines include derivatives such as acetyl and propionyl such as 4-acetamidophenol.
Examples of the compound having the structure represented by the general formula (v) include aromatic aminocarboxylic acids and amide derivatives thereof, such as 4-aminobenzoic acid, 3-aminobenzoic acid, and 6-amino-2-naphthoic acid. Acids, aromatic aminocarboxylic acids such as 6-amino-1-naphthoic acid; 3-methyl-4-aminobenzoic acid, 3,5-dimethyl-4-aminobenzoic acid, 2,6-dimethyl-4-aminobenzoic acid Acids, alkyl-substituted products of aromatic aminocarboxylic acids such as 6-amino-5-methyl-2-naphthoic acid; 3-methoxy-4-aminobenzoic acid, 3,5-dimethoxy-4-aminobenzoic acid, 6- Alkoxy-substituted products of aromatic aminocarboxylic acids such as amino-5-methoxy-2-naphthoic acid; and 3-chloro-4-aminobenzoic acid, 2-chloro-4-aminobenzoic acid, 2,3-dichloro-4 Aminobenzoic acid, 3,5-dichloro-4-aminobenzoic acid, 2,5-dichloro-4-aminobenzoic acid, 3-bromo-4-aminobenzoic acid, 6-amino-5-chloro-2-naphthoic acid And halogen-substituted products of aromatic aminocarboxylic acids such as 6-amino-7-chloro-2-naphthoic acid and 6-amino-5,7-dichloro-2-naphthoic acid. Examples of amide derivatives of these aromatic aminocarboxylic acids include derivatives such as acetyl and propionyl such as 4-acetamidobenzoic acid.
The aromatic polyester is preferably a liquid crystal polyester that exhibits anisotropy when melted, and is particularly preferably a wholly aromatic liquid crystal polyester.
The wholly aromatic liquid crystal polyester includes, for example, structural units represented by the following general formulas (I), (II), (III), and (IV), and the ratio of each structural unit is the structural unit (I) 40 to 75 mol%, structural unit (II) 8.5-30 mol%, structural unit (III) 8.5-30 mol%, structural unit (IV) 0.1-8 mol% (where structural unit (I ) To (IV) is 100 mol%)).

(Where Ar ₁ Is 2,6-naphthalene, Ar ₂ Is at least one selected from 1,2-phenylene, 1,3-phenylene and 1,4-phenylene, Ar ₃ Is at least one residue of 1,3-phenylene, 1,4-phenylene, or a compound having two or more phenylenes linked in the para position, Ar ₄ Is 1,4-phenylene. )
Specifically, as the raw material representing each structural unit, for example, 2-hydroxy-6-naphthoic acid is provided as (I), and the aromatic diol component (III) is provided as (II). As the above-mentioned aromatic dicarboxylic acid component, polyesters exhibiting melt anisotropy combined with 4-hydroxybenzoic acid as those giving (IV) can be mentioned, among which (I), (II), (III) and (IV) The production method of the present invention exhibits its effect remarkably because there are many sublimates during the polymerization reaction.
Polymerization equipment
The polymerization apparatus used in the present invention is a batch polymerization apparatus, and may be an apparatus having one reaction tank so that polycondensation is performed in one stage, but two or more tanks for performing two or more stages of polycondensation. An apparatus having the reaction vessel of In this case, the first stage is used for acylation and the second and subsequent stages are used for polycondensation.
The polymerization apparatus in which polycondensation is performed includes a reaction tank having a raw material supply port and a polymer discharge port, a stirring device provided in the reaction tank, a distillation pipe, a reaction temperature management device, and a reaction pressure management device.
Examples of the temperature management device include a jacket or a heater described later.
In the present invention, since it is necessary to cool the reactor part in contact with the reaction space, that is, the upper part of the reactor, it is preferable to separately provide upper and lower heating means (jacket or heater) of the reactor. From the viewpoint of temperature control, a jacket is preferably used, and the heat medium is circulated through an external heat exchanger so as to be cooled to a predetermined temperature.
Examples of the pressure management device include a vacuum pump, an ejector, and a pressure gauge for measuring pressure.
The distillation pipe is preferably composed of a refluxer (condenser) which will be described later and a nozzle protruding into the reaction tank, but may not necessarily protrude into the reaction tank.
An example of a manufacturing apparatus used in the present invention is shown in FIG. Hereinafter, description will be given with reference to FIG. In FIG. 1, 1 is an acylation reaction tank, 2 is a feed line, 3 is a reflux line, 4 is a line to a distillate collector, 5 is a stirrer, 6 is a heating means, and 7 is an acylation reaction. 8 is an acylation reactant transfer tank line, 9 is a suction line, 10 is a generated polymer discharge port, 11 is a generated polymer discharge line, 12 is a polycondensation reaction tank, and A is a distillate protruding into the reaction tank. This is the lower end (nozzle) of the tube.
From line 2, raw material aromatic compound and acylating agent are supplied. These may be supplied from a separate supply line for each monomer species.
Usually, acylation is performed in a first-stage acylation reaction tank (sometimes referred to as a preliminary reaction tank). One or two or more hydroxyl group-containing aromatic compounds supplied together with the acylating agent are converted to ester derivatives by an acylation reaction. It is the raw material hydroxyl group-containing aromatic compound that undergoes such an acylation reaction, but the amino group-containing compound is also acylated. In the present invention, most hydroxyl group-containing compounds are preferably acylated in an acylation reaction tank and supplied to the polycondensation reaction tank 12.
As another method, an acylation reaction product can be produced prior to polycondensation in the reaction vessel 12 without providing the reaction vessel 1.
As the acylating agent, an acid anhydride is usually used, and examples of the acid anhydride include monohydric carboxylic acid anhydrides having 1 to 6 carbon atoms, such as acetic anhydride, propionic anhydride, and butyric anhydride. Acetic anhydride is preferably used. The acylation reaction proceeds while removing fatty acids such as acetic acid by-produced by a reflux line attached to the acylation reaction tank. A part or all of the acylated hydroxyl group-containing aromatic compound or the like supplied to the reaction vessel 12 may be an oligomer.
The reaction tank 12 is usually supplied with a catalyst from a line (not shown). As the catalyst, known catalysts used for the production of general polyester resins, for example, germanium compounds such as germanium oxide, tin compounds such as stannous oxalate, stannous acetate, dialkyltin oxide, and diaryltin oxide And titanium compounds such as titanium dioxide, titanium alkoxides, and alkoxy titanium silicates, and metal salts of organic acids such as sodium acetate, potassium acetate, calcium acetate, zinc acetate, and ferrous acetate. The amount of catalyst is 10 to 100 ppm, preferably 20 to 80 ppm, based on parts by weight of the metal based on the polymer produced.
In the reaction tank 12, the reaction mixture is stirred by the stirrer 5 and heated from the outside by a heating means 6 such as a jacket or a heater using a heating medium, and the generated fatty acid such as acetic acid is distilled off from the line 9. Polycondensation proceeds. At that time, since an expensive monomer such as an ester compound is distilled off together with the fatty acid, a reflux unit 3 is provided to return the reflux liquid together with the fatty acid to the reaction mixture.
In the present invention, the reflux liquid can be dropped into the reaction mixture without being transmitted along the inner wall of the reaction vessel. For this purpose, it is preferable to install a nozzle A protruding into the reaction vessel 12 in the refluxing device 3. The protruding length of the nozzle A may be such that the reflux liquid is not transmitted to the inner wall of the reaction tank 12.
Polycondensation proceeds by distilling out fatty acids, but in the final stage, the pressure in the reaction tank 12 is reduced from the suction line 9 to remove fatty acids as volatile components. When the polycondensation is completed, the obtained liquid crystalline polymer in a molten state is taken out of the reaction tank via the discharge port 10 and the discharge line 11 provided in the lower part of the reaction tank 12.
Reaction conditions
When the reaction vessel is used in a single unit, the raw material monomer is usually charged and the temperature is raised to about 140 to 200 ° C. in a nitrogen atmosphere, and stirring is started simultaneously with the temperature rise. After carrying out the acylation reaction while distilling the distillate produced by the acylation reaction and the unreacted acylating agent, the temperature is raised to 300 to 400 ° C., and polycondensation is carried out under reduced pressure or under vacuum.
As shown in FIG. 1, when two or more reaction vessels are used, usually, the raw material monomer and acylating agent are charged into the reaction vessel 1, and after stirring, the temperature is raised to 130 to 200 ° C. While distilling the distillate produced by acylation and the unreacted acylating agent, acylation is carried out for 1 to 2 hours. Next, it transfers to the reaction tank 12 with the vacuum generator, and it heats up until it reaches the final reaction temperature of about 300-400 degreeC, and polycondensates under pressure reduction or a vacuum. The final reaction temperature is the final temperature reached by the reaction liquid during the polycondensation reaction.
The important point in the present invention is that during the polycondensation, the reaction mixture such as monomers or oligomers from the reaction mixture adheres to the reaction vessel wall, the reflux condenser of the distillation pipe, the distillate aggregation condenser nozzle, etc. In this way, polycondensation is performed while suppressing the occurrence of undesired reactions such as decomposition reaction and coloring.
Therefore, in the present invention, it is important to carry out the reaction under the following conditions.
(1) The temperature of the part to which the reaction mixture adheres, that is, the part of the reaction apparatus that contacts the reaction space above the reaction liquid surface during the polycondensation reaction, specifically the upper lid of the reaction tank and the inlet part of the distillate aggregation condenser , 150-300 ° C. Even if the sublimate adheres to the reaction tank, polycondensation can be performed while washing the inside of the reaction tank by filling the reaction distillate vapor into the tank. It can be melted at a temperature about the melting point of the polymer without receiving the heat history. When the temperature is set to less than 150 ° C., heat is lost due to insufficient heat retention due to a difference from the set temperature of the reaction tank, and the temperature of the reaction tank decreases. Further, when the temperature exceeds 300 ° C., the sublimate receives a heat history and changes to a substance that does not melt, and there is a risk of causing problems such as clogging of the distillation pipe and mixing into the polymer. More preferably, the reaction is performed under the conditions satisfying the following (2) to (4).
(2) The degree of vacuum at the time of reduced pressure polycondensation is controlled in the range of 25 to 200 Torr. When polycondensation is performed at a vacuum level of less than 25 Torr, sublimates are often generated during decompression, which causes clogging of the distilling tube. Further, when the degree of vacuum is higher than 200 Torr, there is a problem that the polycondensation reaction becomes very slow although there are few sublimates.
(3) The reaction temperature is 140 to 400 ° C., and the temperature is raised at 2.0 ° C./min or less, preferably 1.0 ° C./min or less. The heating rate up to the final temperature is 1 ° C./min or less, preferably 0.5 ° C./min or less.
(4) An acylating agent is added in an amount of 1.02 to 1.06 times the amount corresponding to the hydroxyl equivalent or amino equivalent of the aromatic compound having a phenolic hydroxyl group or amino group as a raw material, and acylated. When the acylating agent is less than 1.02 times, the acylation reaction does not proceed sufficiently, and when it is more than 1.06 times, an unexpected reaction such as a crosslinking reaction may occur in addition to the acylation reaction. .
Examples of means for controlling the temperature of the reaction vessel top lid, distillation pipe, etc. to 150 to 300 ° C. include heating means such as a band heater and a jacket through which a temperature-controlled heating medium flows.
Example
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
[Example 1]
Using the reaction tank 1 having an internal volume of 6 L having a paddle blade without a central axis and the reaction tank 2 having an internal volume of 6 L having a double helical blade without a central axis, the reaction was carried out as follows.
1218 g of 2-hydroxy-6-naphthoic acid as a raw material for giving (I) to the reaction tank 1, 560 g of terephthalic acid as a raw material for giving (II), 628 g of 4,4′-dihydroxydiphenyl as a raw material for giving (III), (IV ) Was charged with 37 g of 4-hydroxybenzoic acid and 1432 g of acetic anhydride (1.04 equivalent times the hydroxyl group). The inside of the tank was stirred at 70 to 150 rpm, reached 140 ° C., reacted at 140 ° C. for 2 hours, and then heated to 200 ° C. After reaching 200 ° C., the reaction solution was transferred to the reaction vessel 2 and stirred at 70 rpm, and the reaction vessel solution temperature was raised to 360 ° C. The temperature of the upper part of the reaction tank 2 was set to a predetermined 200 ° C. so as not to exceed the temperature of the reaction product in the tank. The temperature increase rate from the reaction vessel liquid temperature of 280 ° C. to 360 ° C. was 0.5 ° C./min. After reaching the final reaction temperature, the pressure was reduced from normal pressure to about 75 Torr of the final pressure reduction over about 40 minutes.
After completion of the polycondensation reaction, the inside of the reaction tank 12 is about 2 kg / cm. ² Pressurized to a certain degree, the polymer was discharged into a strand, and after cooling, cut into pellets. The operating conditions were as described in Table 1.
The results are shown in Table 1. In addition, ○ indicates that batch-type continuous polymerization is possible, Δ indicates that batch-type continuous polymerization is possible several times, and x indicates that batch-type continuous polymerization is not possible.
[Examples 2 to 4 and Comparative Examples 1 to 3]
The reaction was performed in the same manner as in Example 1 except that the reaction conditions were changed as shown in Table 1. The results are shown in Table 1.

Industrial applicability
According to the present invention, an aromatic polymer is produced by batch-type continuous polymerization without causing a raw material aromatic compound or oligomer to adhere to the space of the polymerization apparatus, causing clogging, or discoloration to deteriorate the quality. Can do.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a polymerization apparatus used in the method for producing an aromatic polymer according to the present invention.

Claims (9)

Using a polymerization apparatus having a reaction vessel having a raw material supply port and a polymer discharge port, a stirrer, a distilling tube, a reaction temperature control device and a reaction pressure control device, the aromatic polymer raw material has a final reaction temperature of 300 to 400 ° C. When the aromatic polymer is batch-produced by polycondensation within the range, the temperature of the reactor part in contact with the reaction space above the reaction liquid surface is maintained at 150 to 300 ° C. during the polycondensation reaction. A method for producing an aromatic polymer. (1) The final reaction temperature is in the range of 300 to 400 ° C., and the temperature is raised from 280 ° C. to the final reaction temperature at 0.5 ° C./min or less. (2) After reaching the final reaction temperature, in the reaction system 2. The method for producing an aromatic polymer according to claim 1, wherein the polycondensation is performed by reducing the pressure to 25 to 200 Torr. The method for producing an aromatic polymer according to claim 1 or 2, wherein the distilling pipe has a refluxer and a nozzle protruding into the reaction vessel. The manufacturing method according to claim 3, wherein the temperature of the nozzle is 150 to 300 ° C. The method for producing an aromatic polymer according to any one of claims 1 to 4, wherein the production is repeated batchwise without washing the polymerization apparatus. The method for producing an aromatic polymer according to any one of claims 1 to 5, wherein at least one of compounds having a structure represented by the following general formulas (i) to (v) is used as a polymer raw material. .

(Where Ar ¹ and Ar ⁵ are phenylene or naphthalene, Ar ² is phenylene, naphthalene, or a compound residue having two or more phenylenes connected at the meta or para position, Ar ³ is phenylene, polyphenylene, naphthalene, meta or para A compound residue having 2 or more phenylenes connected at the position, Ar ⁴ is a compound residue having 2 or more phenylenes connected at the meta or para position, such as phenylene, naphthalene, or a hydrogen atom of an aromatic ring of Ar ^{1 to} Ar ⁵ . Some may be substituted with lower alkyl, lower alkoxy, halogen, nitro, phenyl, phenoxy groups. The aromatic polymer is composed of structural units represented by the following general formulas (I), (II), (III) and (IV), and the proportion of each structural unit is 40 to 75 mol% of the structural unit (I), Structural unit (II) 8.5-30 mol%, structural unit (III) 8.5-30 mol%, structural unit (IV) 0.1-8 mol% (wherein structural units (I)-(IV The aromatic polymer according to any one of claims 1 to 6, which is a wholly aromatic polyester that exhibits optical anisotropy when melted. Manufacturing method.

(Where Ar ₁ is 2,6-naphthalene, Ar ₂ is at least one selected from 1,2-phenylene, 1,3-phenylene and 1,4-phenylene, Ar ₃ is 1,3-phenylene, , 4-phenylene, or at least one residue of a compound having two or more phenylenes linked in the para position, Ar ₄ is 1,4-phenylene.) The method for producing an aromatic polymer according to claim 1, wherein the aromatic polymer is a wholly aromatic liquid crystal polymer. When using an aromatic compound having a phenolic hydroxyl group and / or an aromatic amino group as a raw material, 1.02 to 1.06 times the amount of phenolic hydroxyl group and / or aromatic amino group equivalent, 1 carbon number The method for producing an aromatic polymer according to claim 1, wherein an acylating agent of ˜6 is added to acylate a phenolic hydroxyl group and / or an aromatic amino group.

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