JP2004211008A - Biodegradable copolymer and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a biodegradable copolymer which has biodegradability, practically sufficient mechanical strength, excellent moldability and a sufficiently high molecular weight. <P>SOLUTION: The biodegradable copolymer is mainly composed of an aliphatic diol unit, an aliphatic dicarboxylic acid unit and a polyether and/or polyester polyol unit which has three or more hydroxy groups and a number-average molecular weight of 200 or more, and optionally an aliphatic oxycarboxylic acid unit is added. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００１３】
【化２】

【００１４】
【化３】

【００１５】
【化４】

【００１６】
【化５】

【００１７】
【化６】

【００１８】
【化７】

【００１９】
【化８】

【００２０】
ポリエーテルポリオール単位またはポリエステルポリオール単位の共重合体中の重量割合をＸ％、該ポリオールの数平均分子量をＭとした場合、下記の（式１）を満たすことが好ましい。
０．００５≦Ｘ／Ｍ×１００≦１．５ （式１）
（式１）におけるＸ／Ｍが０．００５より少ないと物性改良効果、成形性改良効果が現れない傾向があり、１．５より多いと溶融粘度・溶融張力が上がりすぎて成形加工性を損なったり、柔軟性を損なって脆くなってしまう傾向がある。好ましくは、０．０１≦Ｘ／Ｍ≦０．５である。この多官能ポリオールの分子量、使用量、構成成分を変化させることによって用途に適した機械的物性と成形加工性を付与することができる。
【００２１】
脂肪族ジオール単位を構成する脂肪族ジオールとしては、例えばエチレングリコール、トリメチレングリコール、１，３−プロパンジオール、１，４−ブタンジオール、１，５−ペンタンジオール、１，６−ヘキサンジオール、１，４−シクロヘキサンジオール及び１，４−シクロヘキサンジメタノール等が挙げられる。これらの中で、得られる共重合体の物性の面から、１，４−ブタンジオール及びエチレングリコールが好ましく、特に１，４−ブタンジオールが好ましい。これらは単独でも、二種以上の混合物として使用することもできる。好ましい脂肪族ジオール単位はポリオールを除いた共重合体中３５〜５０モル％である。
【００２２】
脂肪族ジカルボン酸単位を構成するジカルボン酸の具体例としては、シュウ酸、コハク酸、グルタル酸、アジピン酸、セバシン酸及びドデカン二酸、１，６−シクロヘキサンジカルボン酸等が挙げられる。また、これらの低級アルキルエステル等の誘導体及び酸無水物等も挙げられる。これらの中で、物性の面から、コハク酸、アジピン酸、セバシン酸及びドデカン二酸が好ましく、特にはコハク酸、またはこれらの混合物が好ましい。これらは単独でも２種以上混合して使用することもできる。好ましい脂肪族ジカルボン酸単位或いは脂環式ジカルボン酸単位はポリオールを除いた共重合体中３５〜５０モル％である。
【００２３】
本発明の生分解性共重合体は、脂肪族ジオール単位と脂肪族ジカルボン酸単位の他に脂肪族オキシカルボン酸単位を含有させても良い。脂肪族オキシカルボン酸単位を構成する脂肪族オキシカルボン酸としては、分子中に１個の水酸基とカルボン酸基を有する脂肪族化合物であれば特に限定されるものではないが、α−ヒドロキシカルボン酸が重合活性の点で最も好ましい。脂肪族オキシカルボン酸の具体例としては、乳酸、グリコール酸、２−ヒドロキシ−ｎ−酪酸、２−ヒドロキシカプロン酸、２−ヒドロキシ３，３−ジメチル酪酸、２−ヒドロキシ−３−メチル酪酸及び２−ヒドロキシイソカプロン酸が挙げられる。これらは単独でも２種以上混合して使用することもできる。
【００２４】
また、これらに光学異性体が存在する場合には、Ｄ体、Ｌ体、またはラセミ体のいずれでもよく、形態としては固体、液体、または水溶液であってもよい。これらの中で、特に好ましいのは、使用時の重合速度の増大が顕著で、かつ入手の容易な乳酸及び／又はグリコール酸であり、最も好ましくは乳酸である。これらの形態は、３０〜９５％の水溶液のものが容易に入手することができるので好ましい。好ましい脂肪族オキシカルボン酸単位は、脂肪族ジカルボン酸単位に対して０．０４〜６０モル％である。
【００２５】
本発明の生分解性共重合体は、高分子量化を達成することができるという点で、脂肪族オキシカルボン酸を含有することが好ましい。更に、得られる生分解性共重合体をポリ乳酸とブレンドした場合などは特に相溶性の点からみても脂肪族オキシカルボン酸を含有することが好ましい。
本発明の生分解性共重合体の還元粘度η_ｓｐ／ｃは、通常１．１以上であるが、さらに好ましくは１．４以上、最も好ましくは１．８以上である。
【００２６】
また、本発明の生分解性共重合体は、適度な溶融粘度と溶融張力を持ち合わせており成形加工性が良好である。１９０℃において測定したメルトインデックスが通常０．１ｇ／１０分以上であり、好ましくは０．５ｇ／１０分以上である。上限値は、通常、５０ｇ／１０分、好ましくは１０ｇ／１０分である。また、１９０℃で測定したメルトテンションが０．５〜５０ｇ、好ましくは１〜２０ｇである。
【００２７】
本発明の生分解性共重合体の製造方法は、ポリエステルの製造に関する公知の方法が採用できる。また、この際の重縮合反応は、従来から採用されている適切な条件を設定することができ、特に制限されない。エステル化反応を進行させた後、減圧操作を行うことによってさらに重合度を高めることができる。脂肪族ジオールの使用量は、脂肪族ジカルボン酸１００モルに対し、実質的に等モルであるが、一般には、エステル化反応中の留出があることから、１〜２０モル％過剰に用いられる。脂肪族オキシカルボン酸を添加する場合は、脂肪族ジカルボン酸１００重量部に対し０．１〜１００重量部の割合で添加して重縮合反応を行う。０．１重量部未満であると添加効果が現れず、１００重量部を超えると結晶性が失われ成形上好ましくなく、耐熱性、機械的特性などが不十分である。好ましい割合は、１．０重量部以上、より好ましくは２．０重量部以上が、また、好ましい上限値は、５０重量部以下、より好ましくは２０重量部以下である。
【００２８】
脂肪族オキシカルボン酸を添加する場合、脂肪族オキシカルボン酸の添加時期及び方法は、重縮合反応以前であれば特に限定されず、例えば、（１） あらかじめ触媒を脂肪族オキシカルボン酸溶液に溶解させた状態で添加する方法、（２） 原料仕込み時触媒を添加すると同時に添加する方法、などが採用される。
ポリエーテルポリオール又はポリエステルポリオールの使用量は、原料仕込み量の５０重量％以下が好ましい。５０重量％以上だとポリマー鎖中の架橋反応が過度に起こり、ゲル化を起こしたり、成形性を損なったりするので好ましくない。これらは、最初の原料仕込み時に添加しても良いし、エステル化反応がある程度進行してから添加しても良く、減圧操作を行う前に添加することが好ましい。
【００２９】
本発明の生分解性共重合体を製造する際の温度、時間及び圧力などの条件は、温度が１５０〜２６０℃、好ましくは１８０〜２３０℃の範囲で選ぶのがよく、重合時間は２時間以上、好ましくは４〜１５時間の範囲で選ぶのがよい。最終的な減圧度は１．３３×１０^３Ｐａ以下、より好ましくは０．２７×１０^３Ｐａ以下で選ぶのがよい。
【００３０】
本発明の生分解性共重合体は、触媒の存在下で製造される。触媒としては、ポリエステルの製造に用いることのできる任意の触媒を選択することができるが、ゲルマニウム、チタン、ジルコニウム、ハフニウム、アンチモン、スズ、マグネシウム、カルシウム、亜鉛などの金属化合物が好適である。中でもゲルマニウム化合物、チタン化合物が好適である。ゲルマニウム化合物としては、特に制限されるものではなく、酸化ゲルマニウム及びテトラアルコキシゲルマニウムなどの有機ゲルマニウム化合物、塩化ゲルマニウムなどの無機ゲルマニウム化合物が挙げられる。価格や入手の容易さなどから、酸化ゲルマニウム、テトラエトキシゲルマニウム及びテトラブトキシゲルマニウムなどが好ましく、特には、酸化ゲルマニウムが好適である。チタン化合物としてはテトラアルコキシチタネートが挙げられる。また、本発明の目的を損なわない限り、他の触媒の併用を妨げない。
【００３１】
触媒の使用量は、使用するモノマー量に対して０．００１〜３重量％、より好ましくは０．００５〜１．５重量％である。触媒の添加時期は、重縮合以前であれば特に限定されないが、原料仕込み時に添加しておいてもよく、減圧開始時に添加してもよい。原料仕込み時に乳酸及び／又はグリコール酸等の脂肪族オキシカルボン酸と同時に添加するか、または脂肪族オキシカルボン酸水溶液に触媒を溶解して添加する方法が好ましく、特には、重合速度が大きくなるという点で脂肪族オキシカルボン酸水溶液に触媒を溶解して添加する方法が好ましい
本発明の生分解性共重合体は、ポリエーテルポリオールまたはポリエステルポリオールの他にも３官能以上のヒドロキシ化合物、３官能以上のオキシカルボン酸、無水トリメリット酸や無水ピメリット酸のような酸無水物や３官能以上のカルボン酸を用いても良い。また、ジイソシアネート、ビスオキサゾリン、ジイミド、エポキシ化合物などの鎖延長剤を使用してもよい。また、ジフェニルカーボネートを添加してポリエステルカーボネートにしても良い。その場合は、ジフェニルカーボネートを２０重量％以下（特に１０重量％以下）とすることが好ましい。また、少量のパーオキサイドを添加することもよい。
【００３２】
本発明の生分解性共重合体には、その生分解性を損なわない程度に芳香族ジカルボン酸等の芳香族化合物を含むこともできる。芳香族ジカルボン酸としては、テレフタル酸、イソフタル酸、ナフタレンジカルボン酸などが用いられ、テレフタル酸を使用する場合には、ジカルボン酸単位中５０モル％以下とすることが生分解性の点から好ましい。
【００３３】
本発明の生分解性共重合体は、射出成形法、中空成形法および押出成形法などの汎用プラスチック成形法などにより、フィルム、ラミネートフィルム、シート、板、延伸シート、モノフィラメント、マルチフィラメント、不織布、フラットヤーン、ステープル、捲縮繊維、筋付きテープ、スプリットヤーン、複合繊維、ブローボトル及び発泡体などの成形品の製造に適用可能である。その際、結晶核剤、酸化防止剤、滑剤、着色剤、離型剤、フィラー、他のポリマーなど、必要に応じ添加することができる。
【００３４】
また、本発明の脂肪族ポリエステル共重合体は、生分解性を有しており、土中のバクテリアによって、完全に分解する特性があり、環境衛生上極めて有用な重合体である。そのため、ショッピングバッグ、ゴミ袋、農業用フィルム、合成紙、化粧品容器、洗剤容器、漂白剤容器、釣り糸、漁網、ロープ、結束材、手術糸、衛生用カバーストック材、保冷箱及びクッション材などの各種の用途に使用可能である。
【００３５】
【実施例】
以下、本発明を実施例により具体的に説明するが、本発明はその要旨を超えない限り、これら実施例に限定されるものではない。
還元粘度（ηｓｐ／ｃ）：実施例及び比較例で得られた共重合体をフェノール／１，１，２，２−テトラクロロエタン（１：１重量比）中、３０℃で溶液濃度０．５ｇ／ｄｌで測定した溶液粘度からもとめた。
【００３６】
メルトインデックス：ＪＩＳ Ｋ７２１０に基づき、メルトインデクサーを用いて１９０℃、荷重２．１６ｋｇにて測定した。
メルトテンション：東洋精機（株）製キャピログラフ１Ｃを用いて、１９０℃、押し出し速度１０ｍｍ／分、引き取り速度３．９ｍ／分、ノズルＬ／Ｄ＝８．１ｍｍ／２．０９５ｍｍにおいて測定した。
【００３７】
熱プレス：上島製作所製ラム径１５０粍、２５０粍角試験用プレス機を用い１７０℃で熱プレスを行い、厚み１７０μｍのフィルムを作成した。
インフレーション成形：エンプラ産業（株）製インフレ成形機を用い１６０℃にて成形を行い、ブロー比約１．７、厚み約５０μｍのフィルムを得た。
引張試験：熱プレスで得られたフィルムからサンプルをダンベル形状に打ち抜き、ＪＩＳ Ｋ７１２７に従って引張試験を行った。また、インフレーション成形で得られたフィルムは、引き取り方向（ＭＤ）とそれに垂直の方向（ＴＤ）でダンベルを打ち抜き、ＪＩＳ Ｋ６７８１に従って引張試験を行った。
【００３８】
^１Ｈ−ＮＭＲ測定：得られた共重合体の各成分のモル分率は、^１Ｈ−ＮＭＲによって測定した。また、ポリオールのモル分率よりポリオールの共重合体中の重量割合を算出した。^１Ｈ−ＮＭＲ測定は、日本電子製 ＪＥＯＬ ＥＸ２７０を用いた。
実施例１
攪拌装置、窒素導入口、加熱装置、温度計及び減圧口を備えた反応容器に、原料としてコハク酸１００．１ｇ、１，４−ブタンジオールを８４．０ｇ、ポリエチレングリコールトリオール（日本油脂（株）製ユニオックスＧ４５０、ＯＨ価：３６０ＫＯＨｍｇ／ｇ、数平均分子量（Ｍ）４６７）０．２ｇ、及び酸化ゲルマニウムをあらかじめ１重量％溶解させた９０％Ｌ−乳酸水溶液５．１ｇを仕込んだ。容器内容物を攪拌下、窒素ガスを導入し、減圧置換によって系内を窒素雰囲気下にした。次に、系内を撹拌しながら２２０℃に昇温し、この温度で１時間反応させた。次に、３０分かけて２３０℃まで昇温し、同時に１時間３０分かけて０．０７×１０^３Ｐａになるように減圧し、０．０７×１０^３Ｐａで４時間反応を行い重合を終了し、白色の共重合体を得た。得られた共重合体の還元粘度（ηｓｐ／ｃ）は２．２０８であった。メルトインデックスは、５ｇ／１０分、メルトテンションは、２．１ｇであった。コハク酸単位と１，４−ブタンジオール単位と乳酸単位のモル分率はそれぞれ、４９．２モル％、４９．０モル％、１．８モル％であった。ポリエチレングリコールトリオール単位の重量割合は、共重合体中０．１３重量％であった。また、得られた共重合体を熱プレスによってフィルムを成形し引張試験を行ったところ、伸び５００％、破断強度４０ＭＰａであった。
【００３９】
実施例２
原料としてコハク酸９９．８ｇ、１，４−ブタンジオールを８３．７ｇ、ポリプロピレングリコールトリオール（日本油脂（株）製ユニオールＴＧ１０００、ＯＨ価：１６０ＫＯＨｍｇ／ｇ、数平均分子量（Ｍ）１０５２）０．８９ｇ、及び酸化ゲルマニウムをあらかじめ１重量％溶解させた９０％Ｌ−乳酸水溶液５．１ｇを仕込み、実施例１と同様の方法で反応を行い、０．０７×１０^３Ｐａで４時間で重合を終了し、白色の共重合体を得た。得られた共重合体の還元粘度（ηｓｐ／ｃ）は２．１５８であった。メルトインデックスは、６．１ｇ／１０分、メルトテンションは、４．５ｇであった。コハク酸単位と１，４−ブタンジオール単位と乳酸単位のモル分率は、４９．５モル％、４８．５モル％、２．０モル％であった。ポリプロピレングリコールトリオール単位の重量割合は、共重合体中０．５８重量％であった。また、得られた共重合体を熱プレスによってフィルムを成形し引張試験を行ったところ、伸び６５０％、破断強度４３ＭＰａであった。
【００４０】
実施例３
原料としてコハク酸９６．０ｇ、１，４−ブタンジオールを８０．４ｇ、ポリプロピレングリコールトリオール（日本油脂（株）製ユニオールＴＧ４０００、ＯＨ価：４２．６ＫＯＨｍｇ／ｇ、数平均分子量（Ｍ）３９５１）６．４ｇ、及び酸化ゲルマニウムをあらかじめ１重量％溶解させた９０％Ｌ−乳酸水溶液４．９ｇを仕込み、実施例１と同様の方法で反応を行い、０．０７×１０^３Ｐａで５時間で重合を終了し、白色の共重合体を得た。得られた共重合体の還元粘度（ηｓｐ／ｃ）は２．２２０であった。メルトインデックスは、４．５ｇ／１０分、メルトテンションは、４．３ｇであった。コハク酸単位と１，４−ブタンジオール単位と乳酸単位のモル分率は、４９．５モル％、４８．５モル％、２．０モル％であった。ポリプロピレングリコールトリオールは共重合体中４．３重量％であった。得られた共重合体を熱プレスによってフィルムを成形し引張試験を行ったところ、伸び７００％、破断強度４２ＭＰａであった。
【００４１】
実施例４
原料としてコハク酸９５．４ｇ、１，４−ブタンジオールを７９．８ｇ、ポリプロピレングリコール−ポリエチレングリコール共重合トリオール（旭硝子（株）製エクセノール２３０、ＯＨ価：５５．５ＫＯＨｍｇ／ｇ、数平均分子量（Ｍ）３０２７）７．３ｇ、及び酸化ゲルマニウムをあらかじめ１重量％溶解させた９０％Ｌ−乳酸水溶液４．９ｇを仕込み、実施例１と同様の方法で反応を行い、０．０７×１０^３Ｐａで３時間で重合を終了し、白色の共重合体を得た。得られた共重合体の還元粘度（ηｓｐ／ｃ）は２．６５３であった。メルトインデックスは、２ｇ／１０分、メルトテンションは、６．３ｇであった。コハク酸単位と１，４−ブタンジオール単位と乳酸単位のモル分率は、４９．５モル％、４８．５モル％、２．０モル％であった。ポリプロピレングリコール−ポリエチレングリコール共重合トリオール単位は共重合体中４．７重量％であった。また、得られた共重合体を熱プレスによってフィルムを成形し引張試験を行ったところ、伸び６９０％、破断強度４３ＭＰａであった。
【００４２】
実施例５
原料としてコハク酸９４．９ｇ、１，４−ブタンジオールを７９．２ｇ、ポリカプロラクトントリオール（ダイセル化学工業（株）製プラクセル３２０、ＯＨ価：８４．３ＫＯＨｍｇ／ｇ、数平均分子量（Ｍ）１９９６）６．４ｇ、及び酸化ゲルマニウムをあらかじめ１重量％溶解させた９０％Ｌ−乳酸水溶液４．９ｇを仕込み、実施例１と同様の方法で反応を行い、０．０７×１０^３Ｐａで５時間で重合を終了し、白色の共重合体を得た。得られた共重合体の還元粘度（ηｓｐ／ｃ）は２．３５０であった。メルトインデックスは、３．７ｇ／１０分、メルトテンションは、５．０ｇであった。コハク酸単位と１，４−ブタンジオール単位と乳酸単位のモル分率はそれぞれ、４９．２モル％、４９．０モル％、１．８モル％であった。ポリカプロラクトントリオール単位の重量割合は、共重合体中５．３重量％であった。また、得られた共重合体を熱プレスによってフィルムを成形し引張試験を行ったところ、伸び６１０％、破断強度４５ＭＰａであった。
【００４３】
実施例６
攪拌装置、窒素導入口、加熱装置、温度計及び減圧口を備えた反応容器に、原料としてコハク酸９９．３ｇ、１，４−ブタンジオールを８３．１ｇ、ポリプロピレングリコール−ポリエチレングリコール共重合トリオール（旭硝子（株）製エクセノール２３０、ＯＨ価：５５．５ＫＯＨｍｇ／ｇ、数平均分子量（Ｍ）３０２７）５．１ｇを仕込んだ。容器内容物を攪拌下、窒素ガスを導入し、減圧置換によって系内を窒素雰囲気下にした。次に、系内を撹拌しながら２２０℃に昇温し、この温度で１時間反応させた。この時点で、テトラブトキシチタネート０．０５ｇを添加した。次に、３０分かけて２３０℃まで昇温し、同時に１時間３０分かけて０．０７×１０^３Ｐａになるように減圧し、０．０７×１０^３Ｐａで５時間反応を行い重合を終了し、白色の共重合体を得た。得られた共重合体の還元粘度（ηｓｐ／ｃ）は２．０５３であった。メルトインデックスは、６．５ｇ／１０分、メルトテンションは、３．０ｇであった。コハク酸単位と１，４−ブタンジオール単位のモル分率はそれぞれ、４９．８モル％、５０．２モル％であった。ポリプロピレングリコール−ポリエチレングリコール共重合トリオール単位は共重合体中３．３重量％であった。また、得られた共重合体を熱プレスによってフィルムを成形し引張試験を行ったところ、伸び６６０％、破断強度４０ＭＰａであった。
実施例７
２７Ｌオートクレーブを用い、原料としてコハク酸３１８１ｇ、１，４−ブタンジオール２６６０ｇ、ポリプロピレングリコール−ポリエチレングリコール共重合トリオール（旭硝子（株）製エクセノール２３０、ＯＨ価：５５．５ＫＯＨｍｇ／ｇ、数平均分子量（Ｍ）３０２７）２４５ｇ、酸化ゲルマニウムをあらかじめ１重量％溶解させた９０％Ｌ−乳酸水溶液１６３ｇを仕込んだ以外は、実施例４と同様に重合反応を行った。得られた共重合体の還元粘度（ηｓｐ／ｃ）は２．６２２であった。また、インフレーション成形によってフィルムを成形し、ＭＤ方向とＴＤ方向の引張試験を行ったところ、以下の結果が得られた。両方向の物性が改良され、異方性が緩和された。
【００４４】

比較例１
撹拌装置、窒素導入口、加熱装置、温度計及び減圧口を備えた反応容器に、コハク酸１００．４ｇ及び１，４−ブタンジオール８４．３ｇ及び酸化ゲルマニウムをあらかじめ１重量％溶解させた９０％乳酸水溶液５．１ｇを仕込んだ。容器内容物を攪拌下、窒素ガスを導入し、減圧置換によって系内を窒素雰囲気下にした。次に、系内を撹拌しながら２２０℃に昇温し、この温度で１時間反応させた。その後、３０分かけて２３０℃に昇温し、同時に１時間３０分かけて０．０７×１０^３Ｐａになるように減圧し、０．０７×１０^３Ｐａで４時間反応を行い重合を終了し、白色のポリエステルを得た。得られたポリエステルの還元粘度（ηｓｐ／ｃ）は１．９８０であった。メルトインデックスは、１０ｇ／１０分、メルトテンションは、０．７ｇであった。コハク酸単位と１，４−ブタンジオール単位と乳酸単位のモル分率はそれぞれ、４９．２モル％、４９．０モル％、１．８モル％であった。また、得られた共重合体を熱プレスによってフィルムを成形し引張試験を行ったところ、伸び３５０％、破断強度３８ＭＰａであった。
【００４５】
比較例２
撹拌装置、窒素導入口、加熱装置、温度計及び減圧口を備えた反応容器に、コハク酸１００．１ｇ及び１，４−ブタンジオール８８．７ｇ及びリンゴ酸０．３４ｇ及び酸化ゲルマニウムをあらかじめ１重量％溶解させた９０％Ｌ−乳酸水溶液５．１ｇを仕込んだ。容器内容物を攪拌下、窒素ガスを導入し、減圧置換によって系内を窒素雰囲気下にした。次に、系内を撹拌しながら２２０℃に昇温し、この温度で１時間反応させた。その後、３０分かけて２３０℃に昇温し、同時に１時間３０分かけて０．０７×１０^３Ｐａになるように減圧し、０．０７×１０^３Ｐａで２時間３０分反応を行い重合を終了し、白色のポリエステルを得た。得られたポリエステルの還元粘度（ηｓｐ／ｃ）は２．３４０であった。メルトインデックスは、４．０ｇ／１０分、メルトテンションは、５．０ｇであった。コハク酸単位と１，４−ブタンジオール単位と乳酸単位のモル分率はそれぞれ、４９．８モル％、４９．０モル％、１．８モル％であった。リンゴ酸はガスクロマトグラフィーにより定量したところ、共重合体中０．１６重量％であった。得られた共重合体を熱プレスによってフィルムを成形し引張試験を行ったところ、伸び３３０％、破断強度４２ＭＰａであった。
【００４６】
比較例３
２７Ｌオートクレーブを用い、原料としてコハク酸３３４０ｇ、１，４−ブタンジオール２９５６ｇ、リンゴ酸１１．４ｇ及び酸化ゲルマニウムをあらかじめ１重量％溶解させた９０％Ｌ−乳酸水溶液１７７ｇを用いた以外は、比較例２と同様に重合反応を行った。得られたポリエステルの還元粘度（ηｓｐ／ｃ）は２．３２０であった。また、インフレーション成形によってフィルムを成形し、ＭＤ方向とＴＤ方向の引張試験を行ったところ、以下の結果が得られ、物性の異方性が観察された。
【００４７】

生分解性試験：実施例１〜６及び比較例１、２で得られた重合体の１７０μｍ厚のダンベル片を三菱化学（株）横浜研究所（住所：横浜市青葉区鴨志田町１０００番地）内の圃場において、平成１４年４月より同年１０月までの６ヶ月間、深さ５ｃｍの土中に水平に埋設し、生分解性能を観察し、結果を表１に示した。実施例１〜６までの全てのサンプルに重量減少があり、白化、穴あきなどの外観変化が観察され、生分解性を有することが確認された。
【００４８】
【表１】

【００４９】
【発明の効果】
本発明によれば、フィルム、シート、繊維その他各種成形品の製造に適した成形性と実用上十分な機械的物性に優れた生分解性の高分子量共重合体を提供することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high molecular weight biodegradable copolymer and a method for producing the same. More specifically, it relates to a biodegradable copolymer having biodegradability, having a practically sufficient high molecular weight, excellent mechanical properties and moldability, and a method for producing the same.
[0002]
[Prior art]
Conventionally, various resins such as polylactic acid, polybutylene succinate, polyethylene succinate, polycaprolactone, and polyhydroxybutyrate have been proposed as biodegradable polymers. However, these biodegradable polymers are characterized by having biodegradability, but compared to resins such as polyolefins, aromatic polyester resins and engineering plastics, the physical properties, especially the mechanical strength, are such that they can withstand practical use. There was a problem that it was not enough. Further, the melt viscosity and the melt tension were small, and the moldability, for example, the film formability by the inflation method was not always sufficient.
[0003]
As means for solving these problems, there has been proposed a method of copolymerizing a small amount of a polyfunctional compound and introducing a branching component into a polymer chain to improve the melt viscosity and the melt tension (for example, Patent Documents 1 and 2). reference.). However, these methods improve moldability but do not improve mechanical properties such as strength and elongation, and are not satisfactory. In addition, when inflation molding is performed, anisotropy occurs in the physical properties in the direction in which the film is taken off (MD direction) and the direction perpendicular to the direction (TD), and there is a problem that the film is particularly weak and easily torn in the TD direction.
[0004]
[Patent Document 1]
JP-A-5-179016
[Patent Document 2]
JP-A-8-259579
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a biodegradable copolymer having biodegradability and having both excellent physical properties and moldability, which can be applied to various fields such as films, molded articles, and fibers.
[0006]
[Means for Solving the Problems]
The present invention relates to a biodegradable copolymer mainly comprising an aliphatic diol unit, an aliphatic dicarboxylic acid unit and a polyether polyol unit and / or a polyester polyol unit having three or more hydroxyl groups and having a number average molecular weight of 200 or more. The subject matter is a polymer.
[0007]
Further, the present invention mainly comprises an aliphatic diol unit, an aliphatic dicarboxylic acid unit, an aliphatic oxycarboxylic acid unit and a polyether polyol unit having three or more hydroxyl groups and a number average molecular weight of 200 or more and / or The gist is a biodegradable copolymer comprising a polyester polyol unit.
Further, the present invention provides, in the presence of a catalyst, an aliphatic diol, an aliphatic dicarboxylic acid or a derivative thereof and a polyether polyol and / or a polyester polyol having three or more hydroxyl groups and a number average molecular weight of 200 or more. The gist of the present invention is a method for producing a biodegradable copolymer, which is characterized by performing a polycondensation reaction.
[0008]
Still further, the present invention relates to an aliphatic diol, an aliphatic dicarboxylic acid or a derivative thereof, an aliphatic oxycarboxylic acid, and a poly (amino acid) having three or more hydroxyl groups and a number average molecular weight of 200 or more in the presence of a catalyst. A gist of the present invention is a method for producing a biodegradable copolymer, which comprises subjecting an ether polyol and / or a polyester polyol to a polycondensation reaction.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The biodegradable copolymer of the present invention is mainly composed of an aliphatic diol unit, an aliphatic dicarboxylic acid unit, and a polyether polyol unit and / or a polyester polyol unit having a number average molecular weight of 200 or more having three or more hydroxyl groups. Alternatively, it is constituted by further adding an aliphatic oxycarboxylic acid unit.
[0010]
The polyether polyol and polyester polyol used in the present invention are polyfunctional compounds having at least three hydroxyl groups. Polyols having 3 or 4 hydroxyl groups are preferred from the viewpoint of easiness of the polymerization reaction. The number average molecular weight is preferably 300 or more. When the molecular weight is too small, the effect of improving the physical properties is small. More preferably, it is 500 or more, most preferably 1000 or more. The upper limit of the number average molecular weight is usually 30,000, preferably 20,000. If the molecular weight is too large, the heat resistance of the obtained polymer may be impaired. The number average molecular weight of the polyol is calculated from the hydroxyl value. By introducing such a polyol into the aliphatic polyester, the melt viscosity and the melt tension are improved, and the moldability is improved. In addition, it is possible to achieve moderate flexibility and improvement in toughness. When processed into a film, the tear strength is improved.
[0011]
The component of the polyether polyol is not particularly limited, but is preferably composed of a repeating unit selected from polyethylene glycol, polypropylene glycol, or a random copolymer or a block copolymer thereof. The constituent components of the polyester polyol are not particularly limited, but those composed of polycaprolactone repeating units are preferred. These polyols can be obtained, for example, by reacting a polyether such as glycerin, trimethylolpropane or pentaerythritol as a central compound with a cyclic ether or cyclic ester such as ethylene oxide, propylene oxide or caprolactone. Examples of the compound having three hydroxyl groups include a compound represented by the following chemical formula.
[0012]
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[0013]
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[0014]
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[0015]
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[0016]
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[0017]
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[0018]
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[0019]
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[0020]
When the weight ratio of the polyether polyol unit or the polyester polyol unit in the copolymer is X% and the number average molecular weight of the polyol is M, it is preferable that the following (formula 1) is satisfied.
0.005 ≦ X / M × 100 ≦ 1.5 (Equation 1)
If X / M in (Formula 1) is less than 0.005, the effect of improving physical properties and moldability tends not to be exhibited, and if it is more than 1.5, the melt viscosity and melt tension are too high, resulting in impaired moldability. Or tend to lose flexibility and become brittle. Preferably, 0.01 ≦ X / M ≦ 0.5. By changing the molecular weight, the amount used, and the constituent components of the polyfunctional polyol, mechanical properties and molding processability suitable for the intended use can be imparted.
[0021]
Examples of the aliphatic diol constituting the aliphatic diol unit include ethylene glycol, trimethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, , 4-cyclohexanediol and 1,4-cyclohexanedimethanol. Among these, 1,4-butanediol and ethylene glycol are preferred from the viewpoint of the physical properties of the obtained copolymer, and 1,4-butanediol is particularly preferred. These can be used alone or as a mixture of two or more. The preferred aliphatic diol unit is 35 to 50 mol% in the copolymer excluding the polyol.
[0022]
Specific examples of the dicarboxylic acid constituting the aliphatic dicarboxylic acid unit include oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecandioic acid, 1,6-cyclohexanedicarboxylic acid, and the like. In addition, derivatives of these lower alkyl esters and the like, acid anhydrides and the like are also included. Among them, succinic acid, adipic acid, sebacic acid and dodecane diacid are preferable from the viewpoint of physical properties, and succinic acid or a mixture thereof is particularly preferable. These can be used alone or in combination of two or more. The preferred aliphatic dicarboxylic acid unit or alicyclic dicarboxylic acid unit is 35 to 50 mol% in the copolymer excluding the polyol.
[0023]
The biodegradable copolymer of the present invention may contain an aliphatic oxycarboxylic acid unit in addition to the aliphatic diol unit and the aliphatic dicarboxylic acid unit. The aliphatic oxycarboxylic acid constituting the aliphatic oxycarboxylic acid unit is not particularly limited as long as it is an aliphatic compound having one hydroxyl group and one carboxylic acid group in a molecule. Is most preferable in terms of polymerization activity. Specific examples of the aliphatic oxycarboxylic acid include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid and 2 -Hydroxyisocaproic acid. These can be used alone or in combination of two or more.
[0024]
When these optical isomers are present, they may be in D-form, L-form, or racemic form, and may be in the form of solid, liquid, or aqueous solution. Among them, particularly preferred are lactic acid and / or glycolic acid, which have a remarkable increase in polymerization rate during use and are easily available, and most preferably lactic acid. These forms are preferred because 30-95% aqueous solutions are readily available. The preferred aliphatic oxycarboxylic acid unit is 0.04 to 60 mol% based on the aliphatic dicarboxylic acid unit.
[0025]
The biodegradable copolymer of the present invention preferably contains an aliphatic oxycarboxylic acid from the viewpoint that a high molecular weight can be achieved. Further, when the obtained biodegradable copolymer is blended with polylactic acid, it is preferable to contain an aliphatic oxycarboxylic acid even from the viewpoint of compatibility.
Reduced viscosity η of the biodegradable copolymer of the present invention _sp The value of / c is usually 1.1 or more, more preferably 1.4 or more, and most preferably 1.8 or more.
[0026]
Moreover, the biodegradable copolymer of the present invention has an appropriate melt viscosity and melt tension, and has good moldability. The melt index measured at 190 ° C. is usually 0.1 g / 10 min or more, preferably 0.5 g / 10 min or more. The upper limit is usually 50 g / 10 minutes, preferably 10 g / 10 minutes. The melt tension measured at 190 ° C. is 0.5 to 50 g, preferably 1 to 20 g.
[0027]
As the method for producing the biodegradable copolymer of the present invention, a known method for producing polyester can be employed. The polycondensation reaction at this time can be set under appropriate conditions conventionally used, and is not particularly limited. After the esterification reaction is advanced, the degree of polymerization can be further increased by performing a reduced pressure operation. The amount of the aliphatic diol used is substantially equimolar to 100 mol of the aliphatic dicarboxylic acid, but is generally used in an excess of 1 to 20 mol% due to distillation during the esterification reaction. . When the aliphatic oxycarboxylic acid is added, the polycondensation reaction is performed by adding 0.1 to 100 parts by weight to 100 parts by weight of the aliphatic dicarboxylic acid. If the amount is less than 0.1 part by weight, the effect of addition is not exhibited. If the amount exceeds 100 parts by weight, crystallinity is lost, which is not preferable for molding, and heat resistance and mechanical properties are insufficient. A preferred ratio is 1.0 part by weight or more, more preferably 2.0 parts by weight or more, and a preferred upper limit is 50 parts by weight or less, more preferably 20 parts by weight or less.
[0028]
When the aliphatic oxycarboxylic acid is added, the timing and method of adding the aliphatic oxycarboxylic acid are not particularly limited as long as it is before the polycondensation reaction. For example, (1) dissolving the catalyst in advance in the aliphatic oxycarboxylic acid solution A method in which the catalyst is added in a state where the catalyst is added, (2) a method in which the catalyst is added at the same time as the catalyst is added when the raw materials are charged, and the like are adopted.
The amount of the polyether polyol or polyester polyol to be used is preferably 50% by weight or less based on the charged amount of the raw materials. If it is 50% by weight or more, the crosslinking reaction in the polymer chain excessively occurs, causing gelation or impairing the moldability. These may be added at the time of the initial raw material preparation, or may be added after the esterification reaction has progressed to some extent, and it is preferable to add them before performing the pressure reducing operation.
[0029]
The conditions such as temperature, time and pressure for producing the biodegradable copolymer of the present invention are preferably such that the temperature is in the range of 150 to 260 ° C, preferably 180 to 230 ° C, and the polymerization time is 2 hours. As described above, it is preferable to select the time within the range of 4 to 15 hours. The final degree of decompression is 1.33 × 10 ³ Pa or less, more preferably 0.27 × 10 ³ It is better to choose below Pa.
[0030]
The biodegradable copolymer of the present invention is produced in the presence of a catalyst. As the catalyst, any catalyst that can be used for the production of polyester can be selected, and a metal compound such as germanium, titanium, zirconium, hafnium, antimony, tin, magnesium, calcium, zinc, or the like is preferable. Among them, germanium compounds and titanium compounds are preferred. The germanium compound is not particularly limited, and examples thereof include organic germanium compounds such as germanium oxide and tetraalkoxygermanium, and inorganic germanium compounds such as germanium chloride. From the viewpoint of price and availability, germanium oxide, tetraethoxygermanium, tetrabutoxygermanium, and the like are preferable, and germanium oxide is particularly preferable. Examples of the titanium compound include tetraalkoxy titanates. Also, the use of other catalysts is not prevented unless the object of the present invention is impaired.
[0031]
The amount of the catalyst to be used is 0.001 to 3% by weight, more preferably 0.005 to 1.5% by weight, based on the amount of the monomer used. The time for adding the catalyst is not particularly limited as long as it is before the polycondensation, but it may be added at the time of charging the raw materials, or may be added at the start of depressurization. It is preferable to add simultaneously with an aliphatic oxycarboxylic acid such as lactic acid and / or glycolic acid, or to dissolve a catalyst in an aqueous solution of an aliphatic oxycarboxylic acid, and to add a polymerization rate. In this respect, a method in which a catalyst is dissolved in an aqueous solution of an aliphatic oxycarboxylic acid and added is preferable
The biodegradable copolymer of the present invention may be a polyether polyol or a polyester polyol, or a trifunctional or higher functional hydroxy compound, a trifunctional or higher functional oxycarboxylic acid, or an acid anhydride such as trimellitic anhydride or pimellitic anhydride. Alternatively, a carboxylic acid having three or more functional groups may be used. Further, a chain extender such as diisocyanate, bisoxazoline, diimide, epoxy compound and the like may be used. Further, polyester carbonate may be added by adding diphenyl carbonate. In that case, the content of diphenyl carbonate is preferably 20% by weight or less (particularly 10% by weight or less). It is also possible to add a small amount of peroxide.
[0032]
The biodegradable copolymer of the present invention may contain an aromatic compound such as an aromatic dicarboxylic acid to the extent that the biodegradability is not impaired. As the aromatic dicarboxylic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or the like is used. When terephthalic acid is used, it is preferably 50 mol% or less in the dicarboxylic acid unit from the viewpoint of biodegradability.
[0033]
The biodegradable copolymer of the present invention is produced by a general-purpose plastic molding method such as an injection molding method, a hollow molding method and an extrusion molding method, and the like. The present invention is applicable to the production of molded products such as flat yarns, staples, crimped fibers, tapes with creasing, split yarns, composite fibers, blow bottles, and foams. At that time, a nucleating agent, an antioxidant, a lubricant, a coloring agent, a release agent, a filler, another polymer, and the like can be added as necessary.
[0034]
In addition, the aliphatic polyester copolymer of the present invention has biodegradability, has the property of being completely degraded by bacteria in the soil, and is an extremely useful polymer for environmental hygiene. Therefore, shopping bags, garbage bags, agricultural films, synthetic paper, cosmetic containers, detergent containers, bleach containers, fishing lines, fishing nets, ropes, binding materials, surgical threads, hygienic cover stock materials, cool boxes, cushion materials, etc. It can be used for various applications.
[0035]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples as long as the gist of the present invention is not exceeded.
Reduced viscosity (ηsp / c): The copolymers obtained in Examples and Comparative Examples were dissolved in phenol / 1,1,2,2-tetrachloroethane (1: 1 weight ratio) at 30 ° C. and a solution concentration of 0.5 g. It was determined from the solution viscosity measured in / dl.
[0036]
Melt index: Measured at 190 ° C. under a load of 2.16 kg using a melt indexer based on JIS K7210.
Melt tension: Measured using a Capillograph 1C manufactured by Toyo Seiki Co., Ltd. at 190 ° C., an extrusion speed of 10 mm / min, a take-up speed of 3.9 m / min, and a nozzle L / D = 8.1 mm / 2.095 mm.
[0037]
Hot press: Hot press was performed at 170 ° C. using a press machine for testing ram diameter of 150 mm and 250 mm square manufactured by Ueshima Seisakusho to produce a 170 μm thick film.
Inflation molding: Molding was performed at 160 ° C. using an inflation molding machine manufactured by Enpla Sangyo Co., Ltd. to obtain a film having a blow ratio of about 1.7 and a thickness of about 50 μm.
Tensile test: A sample was punched out of a film obtained by hot pressing into a dumbbell shape, and a tensile test was performed according to JIS K7127. A dumbbell was punched out of the film obtained by the inflation molding in the take-off direction (MD) and the direction perpendicular to the take-up direction (TD), and a tensile test was performed according to JIS K6781.
[0038]
¹ H-NMR measurement: The molar fraction of each component of the obtained copolymer is as follows: ¹ It was measured by 1 H-NMR. The weight ratio of the polyol in the copolymer was calculated from the molar fraction of the polyol. ¹ The H-NMR measurement used JEOL EX270 manufactured by JEOL.
Example 1
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer, and a pressure reducing port, 100.1 g of succinic acid and 84.0 g of 1,4-butanediol as raw materials, polyethylene glycol triol (Nippon Oil & Fats Co., Ltd.) 0.2 g of UNIOX G450 manufactured by OH Corporation, OH value: 360 KOH mg / g, number average molecular weight (M) 467), and 5.1 g of 90% L-lactic acid aqueous solution in which germanium oxide was previously dissolved at 1% by weight were charged. While stirring the contents of the vessel, nitrogen gas was introduced, and the system was replaced with a nitrogen atmosphere by vacuum substitution. Next, the temperature was raised to 220 ° C. while stirring the system, and the reaction was carried out at this temperature for 1 hour. Next, the temperature was raised to 230 ° C. over 30 minutes, and simultaneously 0.07 × 10 5 over 1 hour and 30 minutes. ³ Reduce the pressure to 0.07 × 10 ³ The reaction was carried out at Pa for 4 hours to complete the polymerization, and a white copolymer was obtained. The reduced viscosity (ηsp / c) of the obtained copolymer was 2.208. The melt index was 5 g / 10 minutes, and the melt tension was 2.1 g. The molar fractions of the succinic acid unit, the 1,4-butanediol unit and the lactic acid unit were 49.2 mol%, 49.0 mol%, and 1.8 mol%, respectively. The weight ratio of the polyethylene glycol triol unit was 0.13% by weight in the copolymer. A film was formed from the obtained copolymer by hot pressing, and a tensile test was performed. As a result, the elongation was 500%, and the breaking strength was 40 MPa.
[0039]
Example 2
99.8 g of succinic acid, 83.7 g of 1,4-butanediol as raw materials, 0.89 g of polypropylene glycol triol (Uniol TG1000 manufactured by NOF Corporation, OH value: 160 KOH mg / g, number average molecular weight (M) 1052) And 5.1 g of a 90% aqueous solution of L-lactic acid in which 1% by weight of germanium oxide was previously dissolved, and reacted in the same manner as in Example 1 to obtain 0.07 × 10 ³ The polymerization was completed in 4 hours at Pa to obtain a white copolymer. The reduced viscosity (ηsp / c) of the obtained copolymer was 2.158. The melt index was 6.1 g / 10 minutes, and the melt tension was 4.5 g. The molar fractions of the succinic acid unit, the 1,4-butanediol unit and the lactic acid unit were 49.5 mol%, 48.5 mol%, and 2.0 mol%. The weight ratio of the polypropylene glycol triol unit was 0.58% by weight in the copolymer. A film was formed from the obtained copolymer by hot pressing, and a tensile test was performed. As a result, the elongation was 650% and the breaking strength was 43 MPa.
[0040]
Example 3
96.0 g of succinic acid, 80.4 g of 1,4-butanediol as raw materials, polypropylene glycol triol (Uniol TG4000 manufactured by NOF Corporation, OH value: 42.6 KOHmg / g, number average molecular weight (M) 3951) 6 0.4 g and 4.9 g of a 90% aqueous solution of L-lactic acid in which germanium oxide was previously dissolved at 1% by weight, and the reaction was carried out in the same manner as in Example 1. ³ The polymerization was completed in 5 hours at Pa to obtain a white copolymer. The reduced viscosity (ηsp / c) of the obtained copolymer was 2.220. The melt index was 4.5 g / 10 minutes, and the melt tension was 4.3 g. The molar fractions of the succinic acid unit, the 1,4-butanediol unit and the lactic acid unit were 49.5 mol%, 48.5 mol%, and 2.0 mol%. Polypropylene glycol triol was 4.3% by weight in the copolymer. A film was formed from the obtained copolymer by hot pressing, and a tensile test was performed. As a result, the elongation was 700%, and the breaking strength was 42 MPa.
[0041]
Example 4
95.4 g of succinic acid and 79.8 g of 1,4-butanediol as raw materials, polypropylene glycol-polyethylene glycol copolymer triol (Exenol 230 manufactured by Asahi Glass Co., Ltd., OH value: 55.5 KOH mg / g, number average molecular weight (M ) 3027) 7.3 g, and 4.9 g of a 90% L-lactic acid aqueous solution in which 1% by weight of germanium oxide was previously dissolved, and reacted in the same manner as in Example 1 to obtain 0.07 × 10 7 ³ The polymerization was completed in 3 hours at Pa to obtain a white copolymer. The reduced viscosity (ηsp / c) of the obtained copolymer was 2.653. The melt index was 2 g / 10 minutes, and the melt tension was 6.3 g. The molar fractions of the succinic acid unit, the 1,4-butanediol unit and the lactic acid unit were 49.5 mol%, 48.5 mol%, and 2.0 mol%. The content of the polypropylene glycol-polyethylene glycol copolymerized triol unit was 4.7% by weight in the copolymer. A film was formed from the obtained copolymer by hot pressing, and a tensile test was performed. As a result, the elongation was 690% and the breaking strength was 43 MPa.
[0042]
Example 5
94.9 g of succinic acid and 79.2 g of 1,4-butanediol as raw materials, polycaprolactone triol (Placcel 320, manufactured by Daicel Chemical Industries, Ltd., OH value: 84.3 KOH mg / g, number average molecular weight (M) 1996) 6.4 g and 4.9 g of a 90% aqueous solution of L-lactic acid in which 1% by weight of germanium oxide was previously dissolved were charged, and reacted in the same manner as in Example 1 to obtain 0.07 × 10 7 ³ The polymerization was completed in 5 hours at Pa to obtain a white copolymer. The reduced viscosity (ηsp / c) of the obtained copolymer was 2.350. The melt index was 3.7 g / 10 minutes, and the melt tension was 5.0 g. The molar fractions of the succinic acid unit, the 1,4-butanediol unit and the lactic acid unit were 49.2 mol%, 49.0 mol%, and 1.8 mol%, respectively. The weight ratio of polycaprolactone triol units was 5.3% by weight in the copolymer. A film was formed from the obtained copolymer by hot pressing, and a tensile test was performed. As a result, the film had an elongation of 610% and a breaking strength of 45 MPa.
[0043]
Example 6
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer, and a decompression port, 99.3 g of succinic acid, 83.1 g of 1,4-butanediol as raw materials, and polypropylene glycol-polyethylene glycol copolymer triol ( 5.1 g of Exenol 230 manufactured by Asahi Glass Co., Ltd., OH value: 55.5 KOH mg / g, number average molecular weight (M) 3027) was charged. While stirring the contents of the vessel, nitrogen gas was introduced, and the system was replaced with a nitrogen atmosphere by vacuum substitution. Next, the temperature was raised to 220 ° C. while stirring the system, and the reaction was carried out at this temperature for 1 hour. At this point, 0.05 g of tetrabutoxytitanate was added. Next, the temperature was raised to 230 ° C. over 30 minutes, and simultaneously 0.07 × 10 5 over 1 hour and 30 minutes. ³ Reduce the pressure to 0.07 × 10 ³ The reaction was carried out at Pa for 5 hours to complete the polymerization, and a white copolymer was obtained. The reduced viscosity (ηsp / c) of the obtained copolymer was 2.053. The melt index was 6.5 g / 10 minutes, and the melt tension was 3.0 g. The molar fractions of the succinic acid unit and the 1,4-butanediol unit were 49.8 mol% and 50.2 mol%, respectively. The polypropylene glycol-polyethylene glycol copolymerized triol unit was 3.3% by weight in the copolymer. A film was formed from the obtained copolymer by hot pressing, and a tensile test was performed. As a result, the elongation was 660% and the breaking strength was 40 MPa.
Example 7
Using a 27 L autoclave, 3181 g of succinic acid, 2660 g of 1,4-butanediol, polypropylene glycol-polyethylene glycol copolymer triol (Exenol 230 manufactured by Asahi Glass Co., Ltd., OH value: 55.5 KOHmg / g, number average molecular weight (M) A polymerization reaction was carried out in the same manner as in Example 4 except that 245 g of 3027) and 163 g of a 90% aqueous solution of L-lactic acid in which 1% by weight of germanium oxide was previously dissolved were charged. The reduced viscosity (ηsp / c) of the obtained copolymer was 2.622. Further, when a film was formed by inflation molding and a tensile test was performed in the MD direction and the TD direction, the following results were obtained. The properties in both directions were improved and the anisotropy was relaxed.
[0044]

Comparative Example 1
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer, and a decompression port, 100.4 g of succinic acid, 84.3 g of 1,4-butanediol, and 90% in which 1% by weight of germanium oxide was previously dissolved. 5.1 g of an aqueous lactic acid solution was charged. While stirring the contents of the vessel, nitrogen gas was introduced, and the system was replaced with a nitrogen atmosphere by vacuum substitution. Next, the temperature was raised to 220 ° C. while stirring the system, and the reaction was carried out at this temperature for 1 hour. Thereafter, the temperature was raised to 230 ° C. over 30 minutes, and simultaneously, 0.07 × 10 5 over 1 hour and 30 minutes. ³ Reduce the pressure to 0.07 × 10 ³ The reaction was carried out at Pa for 4 hours to complete the polymerization, and a white polyester was obtained. The reduced viscosity (ηsp / c) of the obtained polyester was 1.980. The melt index was 10 g / 10 minutes, and the melt tension was 0.7 g. The molar fractions of the succinic acid unit, the 1,4-butanediol unit and the lactic acid unit were 49.2 mol%, 49.0 mol%, and 1.8 mol%, respectively. Further, a film was formed from the obtained copolymer by hot pressing, and a tensile test was performed. As a result, the elongation was 350% and the breaking strength was 38 MPa.
[0045]
Comparative Example 2
10.1 g of succinic acid, 88.7 g of 1,4-butanediol, 0.34 g of malic acid and germanium oxide were previously placed in a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and a decompression port. Then, 5.1 g of a 90% aqueous solution of L-lactic acid dissolved therein was charged. While stirring the contents of the vessel, nitrogen gas was introduced, and the system was replaced with a nitrogen atmosphere by vacuum substitution. Next, the temperature was raised to 220 ° C. while stirring the system, and the reaction was carried out at this temperature for 1 hour. Thereafter, the temperature was raised to 230 ° C. over 30 minutes, and simultaneously, 0.07 × 10 5 over 1 hour and 30 minutes. ³ Reduce the pressure to 0.07 × 10 ³ The reaction was carried out at Pa for 2 hours and 30 minutes to complete the polymerization, and a white polyester was obtained. The reduced viscosity (ηsp / c) of the obtained polyester was 2.340. The melt index was 4.0 g / 10 minutes, and the melt tension was 5.0 g. The molar fractions of the succinic acid unit, the 1,4-butanediol unit, and the lactic acid unit were 49.8 mol%, 49.0 mol%, and 1.8 mol%, respectively. Malic acid was determined by gas chromatography to be 0.16% by weight in the copolymer. A film was formed from the obtained copolymer by hot pressing, and a tensile test was performed. As a result, the elongation was 330% and the breaking strength was 42 MPa.
[0046]
Comparative Example 3
Comparative Example except that 27L autoclave was used, and 177 g of a 90% L-lactic acid aqueous solution in which 3340 g of succinic acid, 2956 g of 1,4-butanediol, 11.4 g of malic acid and 1% by weight of germanium oxide were previously dissolved as raw materials were used. A polymerization reaction was carried out in the same manner as in Example 2. The reduced viscosity (ηsp / c) of the obtained polyester was 2.320. In addition, when a film was formed by inflation molding and tensile tests were performed in the MD and TD directions, the following results were obtained, and anisotropy in physical properties was observed.
[0047]

Biodegradability test: 170 μm thick dumbbell pieces of the polymers obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were placed in Mitsubishi Chemical Co., Ltd. Yokohama Laboratory (address: 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi). For 6 months from April 2002 to October 2002, the soil was buried horizontally in a soil having a depth of 5 cm, and the biodegradation performance was observed. The results are shown in Table 1. All of the samples from Examples 1 to 6 had a weight loss, and appearance changes such as whitening and perforation were observed, and it was confirmed that the samples had biodegradability.
[0048]
[Table 1]

[0049]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the biodegradable high molecular weight copolymer excellent in the moldability suitable for manufacture of a film, a sheet | seat, a fiber, and various molded articles and practically sufficient mechanical properties can be provided.

Claims (8)

A biodegradable copolymer mainly comprising an aliphatic diol unit, an aliphatic dicarboxylic acid unit, and a polyether polyol unit and / or a polyester polyol unit having three or more hydroxyl groups and a number average molecular weight of 200 or more. Mainly composed of aliphatic diol units, aliphatic dicarboxylic acid units, aliphatic oxycarboxylic acid units, and polyether polyol units and / or polyester polyol units having three or more hydroxyl groups and having a number average molecular weight of 200 or more. Degradable copolymer. The method according to claim 1 or 2, wherein when the number average molecular weight of the polyether polyol unit and / or the polyester polyol unit is M and the weight ratio of the biodegradable copolymer of the polyol is X%, the following (formula 1) is satisfied. The biodegradable copolymer according to the above.
0.005 ≦ X / M × 100 ≦ 1.5 (Equation 1) A polycondensation reaction of an aliphatic diol, an aliphatic dicarboxylic acid or a derivative thereof, and a polyether polyol and / or polyester polyol having three or more hydroxyl groups and a number average molecular weight of 200 or more in the presence of a catalyst. A method for producing a biodegradable copolymer. In the presence of a catalyst, an aliphatic diol, an aliphatic dicarboxylic acid or a derivative thereof, an aliphatic oxycarboxylic acid, and a polyether polyol and / or polyester polyol having three or more hydroxyl groups and a number average molecular weight of 200 or more are polymerized. A method for producing a biodegradable copolymer, which comprises conducting a condensation reaction. The method for producing a biodegradable copolymer according to claim 5, wherein an aliphatic oxycarboxylic acid is blended in an amount of 0.1 to 100 parts by weight with respect to 100 parts by weight of the aliphatic dicarboxylic acid. The method for producing a biodegradable copolymer according to any one of claims 4 to 6, wherein the catalyst is a germanium compound and / or a titanium compound. The method for producing a biodegradable copolymer according to any one of claims 5 to 7, wherein germanium oxide is dissolved in an aqueous solution of an aliphatic oxycarboxylic acid to cause a polycondensation reaction.