JP4149616B2 - Aramid oligomer nucleating agent - Google Patents

Description

【０００８】
（上記式（１）において、Ａｒ₁及びＡｒ₂はそれぞれ独立に、核置換されていてもよい炭素数６〜１２の２価の芳香族基である。ｎは１〜１０の範囲の単位繰り返し数である。）
で示される繰り返し単位を主たる構造成分とするアラミドオリゴマーからなる造核剤である。
【０００９】
【発明の実施の形態】
本発明におけるアラミドオリゴマーは、芳香族ジアミン成分及び芳香族カルボン酸成分から主としてなる、下記式（１）
【００１０】
【化４】

【００１１】
（上記式（１）において、Ａｒ₁及びＡｒ₂はそれぞれ独立に、核置換されていてもよい炭素数６〜１２の２価の芳香族基である。ｎは１〜１０の範囲の単位繰り返し数である）
で示される繰り返し単位を主たる構造成分とするものである。 上記式（１）において、Ａｒ₁、Ａｒ₂は、フェニレン基、ナフチレン基、ビフェニレン基等の炭素数６〜１２の２価の芳香族基であり、メチル基、エチル基等のアルキル基、フェニル基等のアリール基を置換基として有していてもよい。具体的には、m-フェニレン、p-フェニレン、２，６−ナフチレン、２，７−ナフチレン、１，４−ナフチレン、１，５−ナフチレン、４，４’−ビフェニレン、２，２’−ビフェニレン等を例示することができる。Ａとしてはこれらのうちｍ−フェニレン、ｐ−フェニレンが好ましい。
【００１２】
ｎは１〜１０の範囲の単位繰り返し数である。本発明におけるアラミドオリゴマーは、通常、芳香族カルボン酸（クロリド）と芳香族ジアミンとを塩基存在下に重縮合してアラミドポリマーを製造する際に、副生物として、モルバランスの僅かなずれや末端調節剤の添加により生成する。ここでアラミドオリゴマーはアラミドポリマーを有機溶媒や熱水で洗浄、精製する際に該アラミドポリマーから粉末状に分離されて得ることができ、重合方法や条件により差はあるが、一般には重合度１〜１０、数平均分子量２５０〜２５００の範囲にはいるものである。特に、イソフタル酸クロリドとm-フェニレンジアミンからＴＨＦ懸濁重合法により製造するコーネックスの重合条件の場合、アラミドオリゴマーは重合度１〜４、数平均分子量４００〜１０００程度である。
【００１３】
アラミドオリゴマーの結合様式としては、主として上記式（１）で表わされる繰り返し単位構造が鎖状に一次元的に結合したものであるが、この他に、鎖両末端が結合し環状に巻いた構造を有していてもよい。また、鎖状構造の場合の末端化学構造は、原料の芳香族カルボン酸及び／又は芳香族ジアミンの官能基を反映し、遊離アミノ基、カルボキシル基及びその塩となるが、その他に末端調節剤である単官能性アミンが結合したアミド構造も含まれる。
【００１４】
これらのアラミドオリゴマーは重合、洗浄の際に用いた溶媒や触媒などを含有しており、熱可塑性ポリマーに添加して造核剤として用いる場合、熱水により充分に攪拌洗浄、乾燥することが必要である。この操作により上述した不純物の大部分は除去されるが、ポリマー製造時に使用した金属塩基であるカルシウムイオンが僅かに（0.1wt%程度）オリゴマー中に残存する。これについては、造核剤としてオリゴマーを使用する際には、カルシウム自身がポリマー造核作用を有しており、オリゴマー自身の造核作用と相乗的に作用する為、除かない方がよい。このアラミドオリゴマーを熱可塑性ポリマーの増量剤として多量に使用する場合など、用途によりカルシウム分を完全に除去、精製する必要があれば、オリゴマーをアミド系有機溶媒で熱時洗浄後、水洗乾燥する。アミド系溶媒として適当な溶媒を例示すれば、Ｎ−メチルピロリドン、Ｎ，Ｎ−ジメチルアセトアミド、 Ｎ，Ｎ−ジメチルホルムアミド等を用いることができるが、中でもＮ−メチルピロリドン、Ｎ，Ｎ−ジメチルアセトアミドが好ましい。
【００１５】
アラミドオリゴマーを熱可塑性ポリマーに添加する方法としては、熱可塑性ポリマーに溶融ブレンドしても、あるいは重合時に添加しておいても、攪拌混練が十分であれば問題ないが、攪拌が充分でない場合、オリゴマーが均一に分散しにくくなる為、重合時に加える方が均一な分散体を得やすい。
【００１６】
アラミドオリゴマーの添加量については、該アラミドオリゴマーを熱可塑性ポリマー改質のための造核剤として使用する際はごく少量、具体的には０．０１〜５重量％程度で充分な効果がある。特に５重量％を越えると熱可塑性ポリマーを繊維化した場合、伸度や色調に影響を与える恐れがあるため好ましくない。造核剤としてのオリゴマー添加量は、好ましくは０．０１〜２ｗｔ％、より好ましくは０．１〜１ｗｔ％である。
【００１７】
造核剤として上記アラミドオリゴマーを添加するに好適な熱可塑性ポリマーとしては、例えばポリエステル及びポリアミドを挙げることができる。これは、ポリエステル、ポリアミドがアラミドオリゴマーを添加した場合、重合方法として溶融重合を行える為、均一にアラミドオリゴマーを分散混合しやすく、また熱可塑性ポリマーの溶解度パラメータ（9〜11程度）がアラミドオリゴマーの値（〜12.5）と極端に離れておらず、また近接しすぎてもいないのでアラミドオリゴマーが熱可塑性ポリマーに適度な親和性があり、また完全相溶しないため造核効果が効果的に発現するからと思われる。具体的には、ポリエステルとしてはＰＥＴ（ポリエチレンテレフタレート）、ポリプロピレンテレフタレート、ＰＢＴ（ポリブチレンテレフタレート）、ポリヘキサメチレンテレフタレート、ポリオクタメチレンテレフタレート、ポリデカメテレンテレフタレート、ポリドデカメテレンテレフタレート、 ＰＥＩ（ポリエチレンイソフタレート）、ＰＢＩ（ポリブチレンイソフタレート）、ポリヘキサメチレンイソフタレート、ポリオクタメチレンイソフタレート、ポリデカメテレンイソフタレート、ポリドデカメテレンイソフタレート、 ＰＥＮ（ポリエチレン２，６−ナフタレート）、ポリプロピレン２，６−ナフタレート、ＰＢＴ（ポリブチレン２，６−ナフタレート）、ポリヘキサメチレン２，６−ナレフタレート、ポリオクタメチレン２，６−ナフタレート、ポリデカメテレン２，６−ナフタレート、ポリドデカメテレン２，６−ナフタレート、などの芳香族ポリエステル、及びポリエチレンアジペート、ポリブチレンアジペート、ポリエチレンスクシネート、ポリブチレンスクシネート、ポリグリコール酸などの脂肪族ポリエステル、及びこれら各種ポリエステルの共重合体又はブレンド体を挙げることができる。また、ポリアミドとしては、６−ナイロン、６，６−ナイロン、４，６−ナイロン、６，１０−ナイロン、４−ナイロン等の脂肪族ポリアミド、ポリエチレンテレフタルアミド、ポリブチレンテレフタルアミド、ポリヘキサメチレンテレフタルアミド、ポリオクタメチレンテレフタルアミド、ポリノナメチレンテレフタルアミド、ポリデカメチレンテレフタルアミド、ポリドデカメチレンテレフタルアミド等の半芳香族ポリアミド、及びこれら各種ポリアミドの共重合体又はブレンド体を用いることができる。中でもＰＥＴのように、結晶化速度が極めて遅く、また結晶化の協同性に劣る難成型性ポリエステルでは、造核剤としてアラミドオリゴマーを用いることで効果的に易成型性を付与することができる。
【００１８】
本発明で使用するアラミドオリゴマーは、その他の添加剤、改質剤と併用して熱可塑性ポリマー中に含有されても構わない。かかる添加剤の例として、熱可塑性ポリマーの耐候剤、帯電防止剤、更には他の現行造核剤などをあげることができる。
【００１９】
（作用）
本発明で使用するアラミドオリゴマーは、構造的には非常に剛直な芳香族ポリアミドであるため、化学的架橋構造が分子内に存在せず、また低分子量体にもかかわらず一般の有機溶媒に不溶であり、また加熱によっても融解することなく高温（〜400℃）まで良好な耐熱性を示す。この様な特徴は一般的な有機分子としてはかなり特異であり、無機化合物に類似した物理的特徴を有している。また溶解性パラメータも比較的高く（12.5程度）、ポリエステル、ポリアミド等（溶解性パラメータ9.0〜11.0程度）に対して適度な親／疎性バランスを有しているためポリマーマトリクス中で分子レベルで完全相溶せずに分散する。同時にオリゴマーはポリマーと比較して低分子量である為、比較的容易にポリマーマトリクスへ均一分散させることができる。その結果、オリゴマーは市販造核剤（有機酸の金属塩など）と同様、ポリマーマトリクス中で完全に均一溶解することなく、結晶核生成の好適な微小核になることができると考えられる。この結果、オリゴマーをごく少量（〜1wt%）を添加して重合したポリエステル及びポリアミドはオリゴマーが核となりその結晶化が促進され、易結晶性かつ結晶性の高い、成型性に優れた溶融成型物が提供される。
【００２０】
【発明の効果】
本発明で使用されるアラミドオリゴマーは利用価値のない廃棄物として処理されているが、簡単な精製処理によりポリエステル、ポリアミドの増量剤として使用することでこれらを有効に再利用できる。のみならずこのオリゴマーの造核剤としての使用により、現行の市販造核剤と同等以上の結晶性向上機能を有することが明らかになった。これらの効果は、アラミドオリゴマーが熱可塑性ポリマーマトリクスへ容易に均一分散させるに充分に低分子量であり、かつアミド結合と剛直な芳香環により、硬く耐熱性の分子構造を有するという特徴によると考えられる。このことよりアラミドオリゴマーは熱可塑性ポリマーマトリクスへ分散した場合、熱可塑性ポリマーマトリクス中で完全に均一溶解することなく、結晶核生成の好適な微小核になることができると考えられる。これは市販の造核剤（有機酸の金属塩など）と同様の核形成機構と考えられ、この結果ごく少量（〜1wt%）のオリゴマー添加にも関わらず、ポリエステル及びポリアミドはオリゴマー核による結晶化を促進することができる。
【００２１】
それ故、本発明のアラミドオリゴマーを含む熱可塑性ポリマー組成物の利用分野としては、易結晶性、高結晶性の求められる高弾性率の材料、及び易成型性のハイサイクル成型材料として有用であり、例えば、シートベルト、タイヤコード、プラスチックボトル用のキャップ、電子部材、車両等の大型成型体等に用いることができる。
【００２２】
【実施例】
以下、参考例および実施例によって本発明を更に詳しく説明する。ただし、以下の実施例は本発明を限定するものではない。
【００２３】
１．アラミドオリゴマーの準備
１）スラリ状オリゴマー廃棄物からの水分と塩化物の除去
イソフタル酸クロリドとm-フェニレンジアミンから製造されたスラリ状のポリ（メタフェニレンイソフタルアミド）「コーネックス」のオリゴマー５００ｇをイオン交換水3ｌに懸濁し、７０℃で１時間かけてよく攪拌した。次いで攪拌を止めて静置、オリゴマーが沈殿後に上澄みの水を除去した。この操作を二回繰り返して沈殿物をろ紙によりろ過して水を除き、７０℃で一日減圧乾燥、粉砕することで淡黄色のオリゴマー粉末約５０ｇを得た。収率はスラリ重量比で１０重量％程度。
【００２４】
２）アラミドオリゴマーの溶媒洗浄
１）で得たオリゴマーをよく粉砕し、粒子状にして３０倍量の純粋なＤＭＦに分散した。次いでＤＭＦ対比で１０倍量のジエチルエーテルを添加し、よく攪拌した。系は僅かに着色した溶液と中間のスラリ、そしてスラリ化せず底に沈殿した少量の着色砂状物に分かれた。デカンテーションにより砂状物を除去、スラリをロ別採取し着色分を溶解した溶媒も除去した。更に残余のＤＭＦ等を完全に除去すべく、ソックスレー抽出（溶媒ジエチルエーテル）により洗浄した。最後に固形分を採取、乾燥、粉砕して白色の粉状オリゴマー約３０ｇを得た。洗浄前オリゴマー体比で収率は６０重量％程度。
【００２５】
得られたアラミドオリゴマーの平均重合度（ｎ）は、ＮＭＲ測定により平均２．５であった（数平均分子量にして６００程度）。なお、ＮＭＲ測定には、プロトンＮＭＲ（日本電子 JEOL A-400(400MHz)）を用い、シーケンスを反映したピーク分離に好適な溶媒として、ＤＭＳＯ−ｄ６を用いた。試料は１％塩化リチウムＤＭＳＯ−ｄ６溶液にオリゴマー１０ｍｇを溶解し、ゲル化を防止すべく１４０℃で測定を行なった。
【００２６】
２．熱可塑性ポリマーの重合
上記オリゴマーの存在下で、ポリエステル、またはポリアミドの重合を行った。ポリエステルとしてはＰＥＴ、ＰＢＴ、またポリアミドとしてはナイロン−６を選んだ。何れもオリゴマー分率がポリマー中０．５ｗｔ％乃至は１ｗｔ％となるよう原料モノマーにブレンドし、通常の加熱溶融重合によりポリマーを得た。
【００２７】
３．ＤＳＣによる熱的特性の検討
真空乾燥機中、４０℃、３０mmHgにて４８時間乾燥した試料を各々５．０ｍｇとり、これをアルミニウム製の専用サンプルパンに封入し、測定試料とした。
測定は、ポリマーを昇温後融解し、更に降温し結晶化させる時の熱転移パラメータ（融点、及び結晶化温度とそれらの転移エンタルピー）を同定するべく、ＤＳＣ測定装置（Du pont社製 DSC2000）を用い、窒素気流中、昇温速度５℃／分、測定温度３０℃〜２８０℃（昇温）、ついで１分間恒温保持後、降温速度５℃／分で１００℃まで、冷却した。
【００２８】
［実施例１（コーネックスオリゴマー０．５重量％添加ナイロン−６の重合）］
１００ｍｌの三つ口フラスコ中に２７．７７ｇの精製したε−カプロラクタム（融点６８〜６９℃）とε−アミノカプロン酸３ｇ、更にコーネックスオリゴマーを０．１６ｇ（重合後のポリマー比０．５ｗｔ％）を加え、窒素ガスを送りながら１６０℃で攪拌を開始した。ε−カプロラクタムが融解すると、最初オリゴマーが懸濁して白色となった融液は次第に透明となった。これはオリゴマーが原料モノマーであるε−カプロラクタムに溶解したためと考えられた。温度を次第に上昇して行くと重合反応が進行し系は徐々に粘度を増した。すると最初モノマーに溶解したオリゴマーが再度系から析出して系は白濁した。これは成長オリゴナイロン−６へのオリゴマー分散性が低いためと考えられた。更に温度２６０℃まで上昇し加熱攪拌を続けると白濁した内容物は発泡しながら次第に粘度を増し、それと共に一旦析出したオリゴマーが徐々にポリマーに分散していった。加熱開始より８時間後には高分子量化した生成ナイロン−６にオリゴマーが完全に分散し再度透明粘ちょうな融解物となり重合が完結した。内容物が温かいうちにサンプリングし、ペレット化することでアラミドオリゴマーを含む粗ナイロン−６組成物を得た。このものを粉砕し、窒素雰囲気下、１００℃でを熱水洗浄することによりナイロン−６のオリゴマーを除去した。４０℃で減圧乾燥後、ポリマー加圧熱プレスによりシート状に成型した。このナイロン−６ １２０ｍｇをフェノール／１，１，２，２−テトラクロルエタン混合溶媒（重量比６／４）１０ｍｌに溶解させ、３５℃で還元粘度を測定したところ１.８０であった。これをＯｌｉｇｏ−ＣＮＸ／６−ナイロン＝９９．５／０．５と略す。
【００２９】
また、アラミドオリゴマーを添加することにより、未添加系と比較して降温冷却時の結晶化温度Tcdの上昇、結晶化ピークの鋭化及び結晶化エンタルピーの増加がみられ、アラミドオリゴマーが造核剤として効率的に機能することによるポリマー結晶化速度の増加及び結晶性向上が認められた。これらの結果を表１にまとめた。
【００３０】
［実施例２］
同様な方法で、組成比の異なるＯｌｉｇｏ−ＣＮＸ／６−ナイロン＝９９／１を重合した。これらのポリマーの物性を表１に併記した。
【００３１】
［実施例３（コーネックスオリゴマー０．５ｗｔ％添加ＰＥＴの重合）］
１００ｍｌの三つ口フラスコ中にジメチルテレフタレート１９．４１９ｇ（０．１ｍｏｌ）、エチレングリコール１３．０２ｇ及び酢酸カルシウム０．００９ｇ（０．０５ｍｏｌ％)を加え、窒素雰囲気下で１５０℃に加熱、攪拌を開始した。エステル交換反応の進行につれ、副生するメタノールが留出し始め、登頂温度は６４℃に上昇した。登頂温度を保つように徐々に反応容器の内温を上昇し、６時間かけて最終的に２３０℃に加熱した。理論量のメタノール留出を確認することでエステル交換が完了したことを判断し、反応停止剤の亜リン酸０．００４１ｇ（０．０５ｍｏｌ％）を加えた。ついで熱媒をソルトバスに変えて、三酸化アンチモン０．００８ｇ（０．０３ｍｏｌ)、及び精製したコーネックスオリゴマー０．０９７ｇ（重合後のポリマー中０．５ｗｔ％）を加えて２５０℃、３０ｍｍＨｇで３０分予備重合、次いで２７０〜２８０℃、０．１〜０．３ｍｍＨｇで２２０分重合を行なうことで曳糸性のある、高粘度の溶融ポリマーを得た。内容物が温かいうちにサンプリングし、ペレット化することでコーネックスオリゴマーをブレンド重合したポリエチレンテレフタレートを得た。このポリマー１２０ｍｇをフェノール／１，１，２，２−テトラクロルエタン混合溶媒（重量比６／４）１０ｍｌに溶解させ、３５℃で還元粘度を測定したところ１.２９であった。これをＯｌｉｇｏ−ＣＮＸ／ＰＥＴ＝９９．５／０．５と略す。これらのポリマーの物性を表１に併記した。
【００３２】
［実施例４］
同様な方法で、組成比の異なるＯｌｉｇｏ−ＣＮＸ／ＰＥＴ＝９９／１を重合した。これらのポリマーの物性を表１に併記した。
【００３３】
［実施例５（コーネックスオリゴマー０．５ｗｔ％添加ＰＢＴの重合）］
５００ｍｌの三つ口フラスコ中にジメチルテレフタレート９７．０９５ｇ（０．５ｍｏｌ）、ブタンジオール９４．６４ｇ（１．０５ｍｏｌ）及びテトラブトキシチタン１ｗｔ％トルエン溶液５．１ｍｌ（０．０３ｍｏｌ％）を加え、窒素雰囲気下で１７５℃に加熱、攪拌を開始した。エステル交換反応の進行につれ、副生するメタノールが留出し始め、登頂温度は６４℃に上昇した。登頂温度を保つように徐々に反応容器の内温を上昇し、２時間かけて最終的に１８０℃に加熱した。理論量のメタノール留出を確認することでエステル交換が完了し、ＢＨＢＴ（ビスヒドロキシブチルテレフタレート）が調製できたと判断した。得られたＢＨＢＴ３１ｇを１００ｍｌ容の重合フラスコに取り、精製したコーネックスオリゴマー０．１４２ｇを加え（重合後ポリマー中０．５ｗｔ％）、熱媒をソルトバスに変えて１７５〜１８５℃、常圧で２時間、１９０〜２００℃、３０ｍｍＨｇで１時間予備重合、次いで２３０〜２４０℃、０．１〜０．３ｍｍＨｇで２時間重合を行なうことで曳糸性のある、高粘度の溶融ポリマーを得た。内容物が温かいうちにペレット化することでアラミドオリゴマーをブレンドしたポリブチレンテレフタレートを得た。このポリマー１２０ｍｇをフェノール／１，１，２，２−テトラクロルエタン混合溶媒（重量比６／４）１０ｍｌに溶解させ、３５℃で還元粘度を測定したところ１.７２であった。これをＯｌｉｇｏ−ＣＮＸ／ＰＢＴ＝９９．５／０．５と略す。これらのポリマーの物性を表１に併記した。
【００３４】
［実施例６］
同様な方法で、組成比の異なるＯｌｉｇｏ−ＣＮＸ／ＰＢＴ＝９９／１を重合した。これらのポリマーの物性を表１に併記した。
【００３５】
［比較例１〜３］
比較として、アラミドオリゴマーを含まないナイロン−６、ＰＥＴ及びＰＢＴについて、熱転移特性を評価した。表１に結果を併記した。
【００３６】
【表１】

【００３７】
1) Ｏｌｉｇｏ−ＣＮＸ：コーネックスオリゴマーの略
2)フェノール／１，１，２，２−テトラクロルエタン混合溶媒（重量比６／４）１０ｍｌに１２０ｍｇを溶解させて３５℃で測定した還元粘度。
3)Ｔｍ：融点、ΔＨ：融解エンタルピー、 Ｔｃｄ：結晶化温度、ΔＨ_Tcd：結晶化エンタルピー、半値幅：結晶化時の発熱ピークの半値幅。結晶化速度に半比例する。
【００３８】
以上の結果より、コーネックスオリゴマーはポリエステル、ポリアミドの結晶化促進の造核剤として高い効果を有すると考えられる。オリゴマー添加ポリマーでは結晶性の増大による力学特性の改良が期待され、溶融成型の容易なハイサイクルポリマー、物性改良ポリマー開発のための有用な添加改質剤に展開することが可能と思われる。結果として廃棄物の高付加価値化につながるのみならず、素材の改質という意味でも高い有用性が認められた。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nucleating agent comprising an aramid oligomer. More specifically, the present invention relates to effective use of waste. More particularly, the present invention relates to a nucleating agent comprising an aramid oligomer suitable for a modifier for a polymer member, particularly polyester and polyamide.
[0002]
[Prior art]
In recent years, efforts to conserve resources and reduce waste are becoming a major trend on a global scale from the viewpoint of environmental issues that have become increasingly important. In particular, in the chemical industry that handles raw materials and raw materials that are the source of all products, these problems cannot be avoided. In that sense, recycling of the polymer (and its raw materials) is an object for solving the problem. Currently, polymer and oligomer chemicals and material recycling are being studied and implemented in polyester, polyamide, polyolefin, etc., including those in the research stage. However, other materials (aramid, polycarbonate, polyethersulfone, etc.) are still unexamined. Among them, poly (metaphenylene isophthalamide) (“Conex” (Teijin) and “Nomex” (DuPont)), which is a meta-aramid, has a problem of by-product oligomer treatment in terms of reducing waste. In particular, in the manufacture of Conex by the THF suspension polymerization method, oligomers of about 0.4% of the polymer are formed, and these are difficult to incinerate and costly, and are therefore landfilled without being reused.
[0003]
From this background, if this by-product oligomer can be reused or effectively used in some form as a functional material or polymer additive, it will be valuable in terms of high added value of the material and reduction of environmental impact. It is.
[0004]
[Problems to be solved by the invention]
The purpose of the present invention is to make effective use of this by-product oligomer as a functional material or polymer additive, particularly as a polymer nucleating agent, and as a result, achieve both high added value of existing materials and reduction of environmental burden. It is to provide a practical material in terms of cost, productivity and performance.
[0005]
[Means for Solving the Problems]
The present inventors may wash the by-product aramid oligomer with water, pulverize it after drying, and add it to various polymers, which may have some influence on the physical properties of the resulting polymer material, in particular thermal properties. Thought. This is because the aramid oligomer is an aromatic polyamide that is very rigid in nature, so it is insoluble in common organic solvents despite having no chemical cross-linking structure, and it is not melted by heating (~ 400 This is to show good heat resistance up to (° C.). As a result, polyesters and polyamides polymerized by adding a very small amount (0.01% by weight or more) of oligomers are accelerated in crystallization, and give a melt-molded product with high crystallinity and high crystallinity. The present inventors have found that the by-product aramid oligomer has a function equivalent to or better than that of current nucleating agents as an effective crystal nucleating agent for polyesters and polyamides.
[0006]
That is, the present invention mainly comprises an aromatic diamine component and an aromatic carboxylic acid component, and the following formula (1)
[0007]
[Chemical 3]

[0008]
(In the above formula (1), Ar ₁ and Ar ₂ are each independently a divalent aromatic group having 6 to 12 carbon atoms which may be substituted by a nucleus. N is a unit repeating unit in the range of 1 to 10. Number.)
A nucleating agent composed of an aramid oligomer having a repeating unit represented by
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The aramid oligomer in the present invention is mainly composed of an aromatic diamine component and an aromatic carboxylic acid component.
[0010]
[Formula 4]

[0011]
(In the above formula (1), Ar ₁ and Ar ₂ are each independently a divalent aromatic group having 6 to 12 carbon atoms which may be substituted by a nucleus. N is a unit repeating unit in the range of 1 to 10. Number)
Is a main structural component. In the above formula (1), Ar ₁ and Ar ₂ are divalent aromatic groups having 6 to 12 carbon atoms such as a phenylene group, a naphthylene group, and a biphenylene group, an alkyl group such as a methyl group and an ethyl group, phenyl An aryl group such as a group may be present as a substituent. Specifically, m-phenylene, p-phenylene, 2,6-naphthylene, 2,7-naphthylene, 1,4-naphthylene, 1,5-naphthylene, 4,4′-biphenylene, 2,2′-biphenylene Etc. can be illustrated. Among these, m is preferably m-phenylene or p-phenylene.
[0012]
n is the number of unit repeats in the range of 1-10. The aramid oligomer in the present invention usually has a slight shift in molar balance or terminal as a by-product when an aramid polymer is produced by polycondensation of an aromatic carboxylic acid (chloride) and an aromatic diamine in the presence of a base. Produced by the addition of a regulator. Here, the aramid oligomer can be obtained by separating the aramid polymer into a powder form when the aramid polymer is washed and purified with an organic solvent or hot water, and there are differences depending on the polymerization method and conditions. To 10 and a number average molecular weight in the range of 250 to 2500. In particular, in the case of Cornex polymerization conditions produced from isophthalic acid chloride and m-phenylenediamine by the THF suspension polymerization method, the aramid oligomer has a degree of polymerization of 1 to 4 and a number average molecular weight of about 400 to 1000.
[0013]
The bonding mode of the aramid oligomer is mainly the one in which the repeating unit structure represented by the above formula (1) is one-dimensionally linked in a chain shape. You may have. In addition, the terminal chemical structure in the case of a chain structure reflects the functional group of the aromatic carboxylic acid and / or aromatic diamine of the raw material, and becomes a free amino group, a carboxyl group, and a salt thereof. An amide structure to which a monofunctional amine is bonded is also included.
[0014]
These aramid oligomers contain the solvents and catalysts used for polymerization and washing, and when added to thermoplastic polymers as nucleating agents, they must be thoroughly washed with hot water and dried. It is. Although most of the impurities described above are removed by this operation, a small amount (about 0.1 wt%) of calcium ions, which are the metal base used in the production of the polymer, remains in the oligomer. About this, when using an oligomer as a nucleating agent, since calcium itself has a polymer nucleating action and acts synergistically with the nucleating action of the oligomer itself, it is better not to remove it. If the aramid oligomer is used in a large amount as an extender for a thermoplastic polymer, and if it is necessary to completely remove and purify calcium depending on the application, the oligomer is washed with an amide organic solvent while hot and then dried with water. Examples of suitable solvents for the amide solvent include N-methylpyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide and the like, among which N-methylpyrrolidone, N, N-dimethylacetamide Is preferred.
[0015]
As a method of adding the aramid oligomer to the thermoplastic polymer, there is no problem if the kneading and kneading is sufficient, even if melt blending to the thermoplastic polymer or adding at the time of polymerization, but stirring is not sufficient, Since it becomes difficult to uniformly disperse the oligomer, it is easier to obtain a uniform dispersion when added during polymerization.
[0016]
As for the amount of the aramid oligomer added, a very small amount, specifically about 0.01 to 5% by weight, is sufficient when the aramid oligomer is used as a nucleating agent for thermoplastic polymer modification. In particular, if it exceeds 5% by weight, it is not preferable that the thermoplastic polymer is made into a fiber because it may affect the elongation and color tone. The amount of oligomer added as a nucleating agent is preferably 0.01 to 2 wt%, more preferably 0.1 to 1 wt%.
[0017]
Examples of the thermoplastic polymer suitable for adding the aramid oligomer as a nucleating agent include polyester and polyamide. This is because, when an aramid oligomer is added to a polyester or polyamide, melt polymerization can be performed as a polymerization method. Therefore, it is easy to disperse and mix the aramid oligomer uniformly, and the solubility parameter (about 9 to 11) of the thermoplastic polymer is the same as that of the aramid oligomer. The value (~ 12.5) is not too far from or too close, so the aramid oligomer has a moderate affinity for the thermoplastic polymer and is not completely compatible, so the nucleation effect is effectively expressed. It seems to be from. Specifically, as polyester, PET (polyethylene terephthalate), polypropylene terephthalate, PBT (polybutylene terephthalate), polyhexamethylene terephthalate, polyoctamethylene terephthalate, polydecametylene terephthalate, polydodecameterene terephthalate, PEI (polyethylene isophthalate) ), PBI (polybutylene isophthalate), polyhexamethylene isophthalate, polyoctamethylene isophthalate, polydecameterene isophthalate, polydodecameterene isophthalate, PEN (polyethylene 2,6-naphthalate), polypropylene 2,6- Naphthalate, PBT (polybutylene 2,6-naphthalate), polyhexamethylene 2,6-naphthalate, polyoctamethyle Aromatic polyesters such as 2,6-naphthalate, polydecameterene 2,6-naphthalate, polydodecameterene 2,6-naphthalate, and polyethylene adipate, polybutylene adipate, polyethylene succinate, polybutylene succinate, polyglycol Mention may be made of aliphatic polyesters such as acids, and copolymers or blends of these various polyesters. Polyamides include aliphatic polyamides such as 6-nylon, 6,6-nylon, 4,6-nylon, 6,10-nylon, 4-nylon, polyethylene terephthalamide, polybutylene terephthalamide, polyhexamethylene terephthalate. Semi-aromatic polyamides such as amide, polyoctamethylene terephthalamide, polynonamethylene terephthalamide, polydecamethylene terephthalamide, and polydodecamethylene terephthalamide, and copolymers or blends of these various polyamides can be used. In particular, like PET, a hard moldable polyester having a very low crystallization rate and inferior crystallization cooperativity can effectively impart easy moldability by using an aramid oligomer as a nucleating agent.
[0018]
The aramid oligomer used in the present invention may be contained in the thermoplastic polymer in combination with other additives and modifiers. Examples of such additives include weathering agents for thermoplastic polymers, antistatic agents, and other current nucleating agents.
[0019]
(Function)
The aramid oligomer used in the present invention is a structurally very rigid aromatic polyamide, so that no chemical cross-linking structure exists in the molecule, and it is insoluble in common organic solvents despite its low molecular weight. In addition, it exhibits good heat resistance up to a high temperature (up to 400 ° C.) without melting even by heating. Such characteristics are quite unique as general organic molecules, and have physical characteristics similar to those of inorganic compounds. In addition, the solubility parameter is relatively high (about 12.5), and it has a proper affinity / looseness balance with respect to polyester, polyamide, etc. (solubility parameter about 9.0 to 11.0), so it is completely at the molecular level in the polymer matrix Disperses without being compatible. At the same time, since the oligomer has a low molecular weight compared to the polymer, it can be uniformly dispersed in the polymer matrix relatively easily. As a result, it is considered that the oligomer can be a suitable micronucleus for crystal nucleation without completely homogeneous dissolution in the polymer matrix, like commercial nucleating agents (such as metal salts of organic acids). As a result, polyesters and polyamides polymerized by adding a very small amount (~ 1 wt%) of oligomers are melt-molded products that are easy to crystallize, have high crystallinity, and have excellent moldability. Is provided.
[0020]
【The invention's effect】
The aramid oligomers used in the present invention are treated as wastes having no utility value, but these can be effectively reused by using them as extenders for polyesters and polyamides by a simple purification treatment. Not only that, the use of this oligomer as a nucleating agent has revealed that it has a crystallinity-improving function equivalent to or better than that of the current commercial nucleating agent. These effects are considered to be due to the characteristics that the aramid oligomer has a molecular weight that is sufficiently low to easily disperse uniformly in the thermoplastic polymer matrix and has a hard and heat-resistant molecular structure due to an amide bond and a rigid aromatic ring. . From this, it is considered that when the aramid oligomer is dispersed in the thermoplastic polymer matrix, it can be a suitable micronucleus for crystal nucleation without completely homogeneous dissolution in the thermoplastic polymer matrix. This is thought to be the nucleation mechanism similar to that of commercially available nucleating agents (such as metal salts of organic acids). As a result, despite the addition of very small amounts (~ 1wt%) of oligomers, polyesters and polyamides are crystallized by oligomer nuclei. Can be promoted.
[0021]
Therefore, as a field of application of the thermoplastic polymer composition containing the aramid oligomer of the present invention, it is useful as a material having a high elastic modulus that requires high crystallinity and high crystallinity, and a high cycle molding material that is easy to mold. For example, it can be used for a seat belt, a tire cord, a cap for a plastic bottle, an electronic member, a large molded body such as a vehicle, and the like.
[0022]
【Example】
Hereinafter, the present invention will be described in more detail with reference examples and examples. However, the following examples do not limit the present invention.
[0023]
1. Preparation of aramid oligomers 1) Removal of moisture and chloride from slurry oligomer waste Waste of 500 g of slurry poly (metaphenylene isophthalamide) “Conex” produced from isophthalic acid chloride and m-phenylenediamine was ionized. The suspension was suspended in 3 liters of exchange water and stirred well at 70 ° C. for 1 hour. Next, the stirring was stopped and the mixture was allowed to stand, and the supernatant water was removed after the oligomer precipitated. This operation was repeated twice, the precipitate was filtered through filter paper to remove water, dried under reduced pressure at 70 ° C. for one day, and pulverized to obtain about 50 g of a pale yellow oligomer powder. Yield is about 10% by weight of slurry.
[0024]
2) Solvent washing of aramid oligomer The oligomer obtained in 1) was thoroughly pulverized, made into particles and dispersed in 30 times the amount of pure DMF. Next, 10 times as much diethyl ether as DMF was added and stirred well. The system was divided into a slightly colored solution and an intermediate slurry and a small amount of colored sand that had not slurried and settled to the bottom. The sandy substance was removed by decantation, and the slurry was collected separately to remove the solvent in which the colored matter was dissolved. Furthermore, in order to completely remove the remaining DMF and the like, washing was performed by Soxhlet extraction (solvent diethyl ether). Finally, the solid content was collected, dried and pulverized to obtain about 30 g of a white powdery oligomer. The yield is about 60% by weight compared to the ratio of oligomer before washing.
[0025]
The average degree of polymerization (n) of the obtained aramid oligomer was an average of 2.5 by NMR measurement (about 600 in terms of number average molecular weight). For NMR measurement, proton NMR (JEOL JEOL A-400 (400 MHz)) was used, and DMSO-d6 was used as a solvent suitable for peak separation reflecting the sequence. As a sample, 10 mg of an oligomer was dissolved in a 1% lithium chloride DMSO-d6 solution, and measurement was performed at 140 ° C. to prevent gelation.
[0026]
2. Polymerization of thermoplastic polymer Polyester or polyamide was polymerized in the presence of the above oligomer. PET and PBT were selected as the polyester, and nylon-6 was selected as the polyamide. All were blended with the raw material monomer so that the oligomer fraction was 0.5 wt% to 1 wt% in the polymer, and a polymer was obtained by ordinary heat melt polymerization.
[0027]
3. Examination of thermal characteristics by DSC In a vacuum dryer, 5.0 mg each of samples dried at 40 ° C. and 30 mmHg for 48 hours was taken and enclosed in a dedicated sample pan made of aluminum to obtain a measurement sample.
In order to identify the thermal transition parameters (melting point, crystallization temperature and their transition enthalpies) when the polymer is melted after being heated and then cooled and crystallized, DSC measuring device (DSC2000 manufactured by Du Pont) The sample was heated in a nitrogen stream at a rate of temperature increase of 5 ° C./minute, a measurement temperature of 30 ° C. to 280 ° C. (temperature increase), and then kept constant for 1 minute, and then cooled to 100 ° C. at a temperature decrease rate of 5 ° C./minute.
[0028]
[Example 1 (polymerization of nylon-6 with 0.5% by weight of Conex oligomer)]
In a 100 ml three-necked flask, 27.77 g of purified ε-caprolactam (melting point: 68 to 69 ° C.), 3 g of ε-aminocaproic acid, and 0.16 g of Conex oligomer (polymer ratio after polymerization: 0.5 wt%) And stirring was started at 160 ° C. while feeding nitrogen gas. When ε-caprolactam melted, the melt in which the oligomers were initially suspended and became white gradually became transparent. This was thought to be because the oligomer was dissolved in ε-caprolactam, which is a raw material monomer. As the temperature gradually increased, the polymerization reaction proceeded and the system gradually increased in viscosity. Then, the oligomer first dissolved in the monomer was precipitated again from the system and the system became cloudy. This was thought to be due to the low oligomer dispersibility in the grown oligonylon-6. When the temperature was further raised to 260 ° C. and heating and stirring was continued, the white turbid contents gradually increased in viscosity while foaming, and the oligomers once precipitated gradually dispersed in the polymer. After 8 hours from the start of heating, the oligomer was completely dispersed in the high molecular weight produced nylon-6 and again became a transparent viscous melt, whereby the polymerization was completed. Sampling and pelletizing while the contents were warm gave a crude nylon-6 composition containing an aramid oligomer. This was pulverized and washed with hot water at 100 ° C. in a nitrogen atmosphere to remove the nylon-6 oligomer. After drying under reduced pressure at 40 ° C., it was molded into a sheet by a polymer press hot press. 120 mg of this nylon-6 was dissolved in 10 ml of a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 6/4), and the reduced viscosity measured at 35 ° C. was 1.80. This is abbreviated as Oligo-CNX / 6-nylon = 99.5 / 0.5.
[0029]
In addition, the addition of an aramid oligomer resulted in an increase in the crystallization temperature Tcd during cooling and cooling, sharpening of the crystallization peak and an increase in crystallization enthalpy compared to the non-added system. As a result, it was confirmed that the polymer crystallization rate was increased and the crystallinity was improved. These results are summarized in Table 1.
[0030]
[Example 2]
In the same manner, Oligo-CNX / 6-nylon = 99/1 having a different composition ratio was polymerized. The physical properties of these polymers are shown in Table 1.
[0031]
[Example 3 (Polymerization of PET containing 0.5% by weight of Conex oligomer)]
In a 100 ml three-necked flask, add 19.419 g (0.1 mol) of dimethyl terephthalate, 13.02 g of ethylene glycol, and 0.009 g (0.05 mol%) of calcium acetate, and heat and stir at 150 ° C. in a nitrogen atmosphere. Started. As the transesterification progressed, by-product methanol began to distill and the peak temperature rose to 64 ° C. The internal temperature of the reaction vessel was gradually increased so as to maintain the peak temperature, and finally heated to 230 ° C. over 6 hours. It was judged that transesterification was completed by confirming the theoretical amount of methanol distillation, and 0.0041 g (0.05 mol%) of phosphorous acid as a reaction terminator was added. Next, the heat medium was changed to a salt bath, and 0.008 g (0.03 mol) of antimony trioxide and 0.097 g of purified Cornex oligomer (0.5 wt% in the polymer after polymerization) were added at 250 ° C. and 30 mmHg. Prepolymerization for 30 minutes, followed by polymerization at 270 to 280 ° C. and 0.1 to 0.3 mmHg for 220 minutes, yielded a melt polymer having a spinnability and a high viscosity. Sampling and pelletizing while the contents were warm gave polyethylene terephthalate obtained by blend polymerization of Conex oligomers. When 120 mg of this polymer was dissolved in 10 ml of a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 6/4) and the reduced viscosity was measured at 35 ° C., it was 1.29. This is abbreviated as Oligo-CNX / PET = 99.5 / 0.5. The physical properties of these polymers are shown in Table 1.
[0032]
[Example 4]
In the same manner, Oligo-CNX / PET = 99/1 having different composition ratios were polymerized. The physical properties of these polymers are also shown in Table 1.
[0033]
[Example 5 (Polymerization of PBT with Connex oligomer 0.5 wt%)]
In a 500 ml three-necked flask, 97.095 g (0.5 mol) of dimethyl terephthalate, 94.64 g (1.05 mol) of butanediol and 5.1 ml (0.03 mol%) of tetrabutoxytitanium 1 wt% toluene solution were added. Heating and stirring were started at 175 ° C. under atmosphere. As the transesterification progressed, by-product methanol began to distill and the peak temperature rose to 64 ° C. The internal temperature of the reaction vessel was gradually increased so as to maintain the peak temperature, and finally heated to 180 ° C. over 2 hours. The transesterification was completed by confirming the theoretical amount of methanol distillation, and it was judged that BHBT (bishydroxybutyl terephthalate) could be prepared. Take 31 g of the resulting BHBT in a 100 ml polymerization flask, add 0.142 g of purified Cornex oligomer (0.5 wt% in the polymer after polymerization), change the heat medium to a salt bath, 175 to 185 ° C. at normal pressure Prepolymerization was performed for 2 hours at 190 to 200 ° C. and 30 mmHg, followed by polymerization for 2 hours at 230 to 240 ° C. and 0.1 to 0.3 mmHg, thereby obtaining a high viscosity melt polymer having spinnability. . The polybutylene terephthalate blended with the aramid oligomer was obtained by pelletizing while the contents were warm. When 120 mg of this polymer was dissolved in 10 ml of a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 6/4) and the reduced viscosity was measured at 35 ° C., it was 1.72. This is abbreviated as Oligo-CNX / PBT = 99.5 / 0.5. The physical properties of these polymers are shown in Table 1.
[0034]
[Example 6]
In the same manner, Oligo-CNX / PBT = 99/1 having different composition ratios were polymerized. The physical properties of these polymers are shown in Table 1.
[0035]
[Comparative Examples 1-3]
For comparison, thermal transition characteristics were evaluated for nylon-6, PET, and PBT not containing an aramid oligomer. The results are also shown in Table 1.
[0036]
[Table 1]

[0037]
1) Oligo-CNX: Abbreviation for Conex oligomers
2) Reduced viscosity measured at 35 ° C. by dissolving 120 mg in 10 ml of a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 6/4).
3) Tm: melting point, ΔH: melting enthalpy, Tcd: crystallization temperature, ΔH _Tcd : crystallization enthalpy, half width: half width of exothermic peak during crystallization. It is half proportional to the crystallization rate.
[0038]
From the above results, it is considered that Cornex oligomer has a high effect as a nucleating agent for promoting crystallization of polyester and polyamide. The oligomer-added polymer is expected to be improved in mechanical properties due to increased crystallinity, and can be developed as a high-cycle polymer that can be easily melt-molded, and a useful additive modifier for developing a polymer with improved physical properties. As a result, not only did it lead to high added value of waste, but also high utility was recognized in terms of material reformation.

Claims (5)

Ru Rana or aromatic diamine component and aromatic carboxylic acid component, the following equation (1)

(In the above formula (1), Ar ₁ and Ar ₂ are each independently a divalent aromatic group having 6 to 12 carbon atoms which may be substituted with a nucleus. N is a unit repeat in the range of 1 to 10. nucleating agent consisting of aramid oligomers and configured Construction component a repeating unit represented by a number.).  The nucleating agent according to claim 1, wherein the aramid oligomer is a by-product produced when a wholly aromatic polyamide is produced using m-phenylenediamine and isophthalic acid chloride. Ru Rana or aromatic diamine component and aromatic carboxylic acid component, the following equation (1)

(In the above formula (1), Ar ₁ and Ar ₂ are each independently a divalent aromatic group having 6 to 12 carbon atoms which may be substituted with a nucleus. N is a unit repeat in the range of 1 to 10. is a number.) the repeating units consist aramid oligomer and the thermoplastic polymer to be configured Construction component represented by, and the aramid oligomers crystallinity is increased, which is 0.01 to 5 wt% of the total Thermoplastic polymer composition.  The thermoplastic polymer composition with enhanced crystallinity according to claim 3, wherein the thermoplastic polymer is polyester.  The thermoplastic polymer composition with enhanced crystallinity according to claim 3, wherein the thermoplastic polymer is polyamide.