JP2004244553A - Biodegradable polyester composition, film and packaging sack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible and biodegradable polyester film, having excellent tear strength and weld-cut sealing strength, suitable for use in automatic filling and packaging such as the weld-cut sealing packaging. <P>SOLUTION: This biodegradable polyester composition comprises 95-50 wt% aliphatic copolyester (a) with a ≥40,000 weight average molecular weight the molecular chain of which has repeating units represented by following general formulas (1)-(3): -CO-R<SP>1</SP>-CO- (1) (wherein R<SP>1</SP>represents a 1-12C divalent aliphatic group), -O-R<SP>2</SP>-O- (2) (wherein R<SP>2</SP>represents a 2-12C divalent aliphatic group) and -CO-R<SP>3</SP>-O- (3) (wherein R<SP>3</SP>represents a 1-10C divalent aliphatic group) and 5-50 wt% aromatic copolyester (b) the molecular chain of which has repeating units represented by general formulas (4)-(6): -CO-R<SP>4</SP>-CO- (4) (wherein R<SP>4</SP>represents a 0-8C divalent aliphatic group), -CO-R<SP>5</SP>-CO- (5) (wherein R<SP>5</SP>represents an 8-12C divalent aromatic group) and -O-R<SP>6</SP>-O- (6) (wherein R<SP>6</SP>represents a 2-12C divalent aliphatic group). <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００１８】
（式中、Ｒ^３は炭素数１〜１０の二価脂肪族基を表す。）
式（３’）で、二価脂肪族基Ｒ^３としては、炭素数２〜１０、好ましくは２〜８の鎖状又は環状のアルキレン基が挙げられる。Ｒ^１６は水素、又は脂肪族基もしくは芳香族基である。脂肪族基としては、炭素数１〜６、好ましくは１〜４の直鎖状又は分岐鎖状の低級アルキル基や、シクロヘキシル基等の炭素数５〜１２のシクロアルキル基、芳香族基としては、フェニル基、ベンジル基等が挙げられる。
【００１９】
ヒドロキシカルボン酸としては、例えば、グリコール酸、Ｌ−乳酸、Ｄ−乳酸、Ｄ，Ｌ−乳酸、２−メチル乳酸、３−ヒドロキシ酪酸、４−ヒドロキシ酪酸、２−ヒドロキシ−ｎ−酪酸、２−ヒドロキシ−３，３−ジメチル酪酸、２−ヒドロキシ−２−メチル酪酸、２−ヒドロキシ−３−メチル酪酸、ヒドロキシピバリン酸、ヒドロキシイソカプロン酸、ヒドロキシカプロン酸等を挙げることができる。
前記ヒドロキシカルボン酸はその２分子が結合した環状二量体エステル（ラクチド）であることができる。その具体例としては、グリコール酸から得られるグリコリドや、乳酸から得られるもの等が挙げられる。
ヒドロキシカルボン酸エステルとしては、例えば、上記ヒドロキシカルボン酸のメチルエステル、エチルエステル等や、酢酸エステル等が挙げられる。
【００２０】
ラクトン類としては、前記一般式（３”）で表されるものを挙げることができる。
式（３”）における二価脂肪族基Ｒ^３としては、炭素数４〜１０、好ましくは４〜８の直鎖状又は分岐鎖状のアルキレン基が挙げられる。
ラクトン類の具体例としては、例えば、β−プロピオラクトン、β−ブチロラクトン、γ−ブチロラクトン、β−バレロラクトン、δ−バレロラクトン、δ−カプロラクトン、ε−カプロラクトン、４−メチルカプロラクトン、３，５，５−トリメチルカプロラクトン、３，３，５−トリメチルカプロラクトンなどの各種メチル化カプロラクトン；β−メチル−δ−バレロラクトン、エナントラクトン、ラウロラクトン等のヒドロキシカルボン酸の環状１量体エステル；グリコリド、Ｌ−ラクチド、Ｄ−ラクチド等の上記ヒドロキシカルボン酸の環状２量体エステル等を挙げることができる。中でも、ε−カプロラクトンが好ましい。これらは２種以上のモノマーを混合して使用してもよい。
【００２１】
上記（Ａ）、（Ｂ）および（Ｃ）の３成分の重合反応によって低分子量脂肪族ポリエステル共重合体（ａ’）を合成する場合には、合成工程は、使用する原料の種類によって、例えば、前半の脱水反応が主に進行するエステル化工程と、後半のエステル交換反応が主に進行する重縮合工程とに分けることができる。
エステル化工程は８０℃〜２５０℃、好ましくは１００℃〜２４０℃、さらに好ましくは１４５℃〜２３０℃の反応温度で、０．５〜５時間、好ましくは１〜４時間、７６０〜１００Ｔｏｒｒの条件下で行うことが望ましい。触媒は、必ずしも必要としないが、原料として用いられる脂肪族ジカルボン酸又はジエステル１モルに対して、１０^−７〜１０^−３モル、好ましくは１０^−６〜５×１０^−４モルの量で用いてもよい。
後半の重縮合工程は、反応系を減圧しながら反応温度を高めて２〜１０時間、好ましくは３〜６時間で終了することが望ましく、最終的には１８０℃〜２７０℃、好ましくは１９０℃〜２４０℃の反応温度で減圧度３Ｔｏｒｒ以下、好ましくは１Ｔｏｒｒ以下とすることが望ましい。この工程では、一般的なエステル交換反応触媒を用いる方が好ましく、原料として用いられる脂肪族ジカルボン酸又はジエステル１モルに対して、１０^−７〜１０^−３モル、好ましくは１０^−６〜５×１０^−４モルの量で用いる。この範囲より触媒量が少なくなると反応がうまく進行せず、反応に長時間を要するようになる。一方、この範囲より多くなると重合時のポリマーの熱分解、架橋、着色等の原因となり、また、ポリマーの成形加工において熱分解等の原因となり好ましくない。
合成工程において、脱水反応が主に進行するエステル化工程と、後半のエステル交換反応が主に進行する重縮合工程との両者において用いることのできる触媒としては、以下のような具体例を挙げることができるが、これらの触媒は単独で用いても、２種以上組合せて用いてもよい。
触媒としては、ＷＯ ０２−４４２４９号公報に記載のものが使用可能である。
【００２２】
脂肪族ポリエステル共重合体（ａ）又は（ａ’）を合成する工程において、原料（Ａ）成分および（Ｂ）成分の仕込み比は、以下の条件式（ｉ）に合致するように選択することが望ましい。
１．０≦［Ｂ］／［Ａ］≦２．０ （ｉ）
（式中、［Ａ］は（Ａ）成分のモル数、［Ｂ］は（Ｂ）成分のモル数を表す。）
［Ｂ］／［Ａ］の値が１より小さいと、所望の分子量の脂肪族ポリエステル共重合体を得ることが難しいだけでなく、生成する脂肪族ポリエステル共重合体のカルボン酸末端の割合が高くなるため加水分解反応を受けやすくなる。また［Ｂ］／［Ａ］の値が２より大きくなるにつれて、生成する脂肪族ポリエステル共重合体のカルボン酸末端の割合が小さくなるため、耐加水分解性に優れたものが得られるが、一方、高分子量体を得るために除去すべき（Ｂ）成分の量が多くなるために、長時間の反応が必要となる。
本発明では、最終的に実用的なフィルム強度を有する脂肪族ポリエステル共重合体（ａ）を得るために、溶融状態の低分子量脂肪族ポリエステル共重合体（ａ’）にジイソシアネート化合物を加えて重量平均分子量を４０，０００以上に高めるようにしてもよい。
【００２３】
上記ジイソシアネート化合物としては、好ましくは脂肪族ジイソシアネート化合物であり、具体的にはヘキサメチレンジイソシアネート、リジンジイソシアネートメチルエステル｛ＯＣＮ−（ＣＨ_２）_４−ＣＨ（−ＮＣＯ）（−ＣＯＯＣＨ_３）｝、トリメチルヘキサメチレンジイソシアネート等が例示されるが、中でもヘキサメチレンジイソシアネートが好ましい。またウレタン結合を含む脂肪族ポリエステル共重合体は、重量平均分子量が前記共重合体（ａ）の範囲と同じであるが、４０，０００以上、通常７０，０００〜３５０，０００、好ましくは１００，０００〜２５０，０００の範囲のものである。
【００２４】
上記において、原料（Ａ）成分、（Ｂ）成分および（Ｃ）成分の仕込み比は以下の条件式（ｉｉ’）に合致するように選択することが好ましい。
０．０１≦［Ｃ］／（［Ａ］＋［Ｂ］＋［Ｃ］）≦０．２５ （ｉｉ’）
（式中、［Ａ］、［Ｂ］、［Ｃ］は、それぞれ（Ａ）成分、（Ｂ）成分、（Ｃ）成分の使用モル数を示す。）
上記式中の［Ｃ］／（［Ａ］＋［Ｂ］＋［Ｃ］）は、脂肪族ポリエステル共重合体（ａ）又は（ａ’）中に含まれる成分（Ｃ）のモル分率を表す。
成分（Ｃ）のモル分率は、好ましくは０．０１５〜０．１５、より好ましくは０．０２５〜０．１２、特に好ましくは０．０２５〜０．１０である。
【００２５】
脂肪族ポリエステル共重合体（ａ）は、重量平均分子量が４０，０００以上、通常、７０，０００〜３５０，０００、好ましくは１００，０００〜２５０，０００の範囲である。
脂肪族ポリエステル共重合体（ａ）の融点は、好ましくは８５〜１２０℃、さらに好ましくは９０〜１１０℃である。また、融点と分解温度との差は１００℃以上と大きく、熱成形も容易である。
上記脂肪族ポリエステル共重合体において、特に、前記一般式（１）〜（３）におけるＲ^１およびＲ^２が（ＣＨ_２）_２または（ＣＨ_２）_４で、Ｒ^３が（ＣＨ_２）_５であるものは、融点が高くかつ結晶性の高いものである。
【００２６】
上記脂肪族ポリエステル共重合体（ａ）は、分子量５００以下のオリゴマーを含むものであってもよいが、その場合は、２０，０００ｐｐｍ以下、好ましくは１５，０００ｐｐｍ以下、特には１０，０００ｐｐｍ以下にしておく必要がある。
【００２７】
芳香族系ポリエステル共重合体（ｂ）
本発明に係る芳香族系ポリエステル共重合体（ｂ）は、前記一般式（４）〜（６）で示される繰返し単位からなる。
芳香族系ポリエステル共重合体（ｂ）において、脂肪族ジカルボン酸残基である繰返し単位（４）は、２０〜９５モル％、好ましくは３０〜７０モル％、更に好ましくは４０〜６０モル％であり、芳香族ジカルボン酸残基である繰返し単位（５）が、５〜８０モル％、好ましくは７０〜３０モル％、更に好ましくは６０〜４０モル％であり、及び脂肪族ジオール残基である繰返し単位（６）は、上記脂肪族ジカルボン酸残基および芳香族ジカルボン酸残基の合計に実質的に等しい。
【００２８】
かかる芳香族系ポリエステル共重合体（ｂ）としては、融点が、好ましくは５０〜２００℃、さらに好ましくは７０〜１７０℃、特に好ましくは１００〜１６０℃の範囲にある。また、芳香族系ポリエステル共重合体（ｂ）のＭＦＲ（ＡＳＴＭ Ｄ−１２３８による、１９０℃、荷重２１６０ｇ）は、脂肪族ポリエステル共重合体（ａ）との組成物で、フィルムが成形できる限り特に限定はされないが、通常０．１〜１００ｇ／１０分、好ましくは０．２〜５０ｇ／１０分、さらに好ましくは０．５〜２０ｇ／１０分の範囲にある。
【００２９】
上記繰返し単位（４）を与える脂肪族ジカルボン酸またはそのエステル形成誘導体としては次のものを例示できる。
上記脂肪族ジカルボン酸は、一般に２〜１０個の炭素原子（カルボキシル基の炭素も含めて）、とくに４〜６個の炭素原子を有する。ジカルボン酸は線状であっても枝分れしていてもよいし、環状（脂環式）であってもよい。環状の脂肪族ジカルボン酸は、通例７〜１０個の炭素原子を有するようなもの、とくに８個の炭素原子を有するようなものである。又、２〜１０個の炭素原子を有する脂肪族ジカルボン酸を主成分とする限り、より大きい炭素原子数、例えば３０個までの炭素原子を有するジカルボン酸も使用することができる。
かかる脂肪族ジカルボン酸としては、具体的には、シュウ酸、マロン酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、アゼライン酸、セバシン酸、フマル酸、２，２−ジメチルグルタル酸、スベリン酸、１，３−シクロペンタジカルボン酸、１，４−シクロヘキサンジカルボン酸、１，３−シクロヘキサンジカルボン酸、ジグリコール酸、イタコン酸、マレイン酸および２，５−ノルボルナンジカルボン酸等が挙げられる。それらの中でもアジピン酸が好ましい。
上記脂肪族ジカルボン酸のエステル形成誘導体としては、例えば、上記脂肪族ジカルボン酸のジメチルエステル、ジエチルエステル、ジ−ｎ−プロピルエステル、ジ−イソプロピルエステル、ジ−ｎ−ブチルエステル、ジ−イソブチルエステル、ジ−ｔ−ブチルエステル、ジ−ｎ−ペンチルエステル、ジ−イソペンチルエステルまたはジ−ｎ−ヘキシルエステルが挙げられる。ジカルボン酸の無水物も同様に使用することができる。
又、脂肪族ジカルボン酸またはそのエステル形成誘導体は、単独かまたはその２種以上からなる混合物として使用することもできる。
特に好ましくは、アジピン酸またはそのアルキルエステルのようなエステル形成誘導体またはそれの混合物が使用される。
【００３０】
上記繰返し単位（５）を与える芳香族ジカルボン酸またはそのエステル形成誘導体としては次のものを例示できる。
本発明に係わる芳香族ジカルボン酸としては、一般に８〜１２個の炭素原子を有するようなもの、とくに８個の炭素原子を有するようなものが挙げられる。具体的には、テレフタル酸、イソフタル酸、２，６−ナフトエ酸および１，５−ナフトエ酸ならびにそのエステル形成誘導体を例示できる。
芳香族ジカルボン酸のエステル形成誘導体としては、上記芳香族ジカルボン酸のジ−Ｃ_１〜Ｃ_６アルキルエステル、例えばジメチルエステル、ジエチルエステル、ジ−ｎ−プロピルエステル、ジ−イソプロピルエステル、ジ−ｎ−ブチルエステル、ジ−ｎ−ブチルエステル、ジ−イソブチルエステル、ジ−ｔ−ブチルエステル、ジ−ｎ−ペンチルエステル、ジ−イソペンチルエステルまたはジ−ｎ−ヘキシルエステル等が挙げられる。
特に好ましくは、テレフタル酸またはジメチルテレフタレートのようなそのエステル形成誘導体が使用される。
又、芳香族ジカルボン酸またはそのエステル形成誘導体は、単独かまたはその２種以上からなる混合物として使用することもできる。
【００３１】
上記繰返し単位（６）を与える脂肪族ジオールまたはその誘導体としては、２〜１２個の炭素原子、好ましくは４〜６個の炭素原子を有する枝分かれまたは線状の脂肪族ジオール、または５〜１０個の炭素原子を有する環状の脂肪族ジオールが挙げられる。
【００３２】
かかる脂肪族ジオールとしては、具体的には、エチレングリコール、１，２−プロパンジオール、１，３−プロパンジオール、１，２−ブタンジオール、１，４−ブタンジオール、１，５−ペンタンジオール、２，４−ジメチル−２−エチルヘキサン−１，３−ジオール、２，２−ジメチル−１，３−プロパンジオール、２−エチル−２−ブチル−１，３−プロパンジオール、２−エチル−２−イソブチル−１，３−プロパンジオール、２，２，４−トリメチル−１，６−ヘキサンジオール、とくには、エチレングリコール、１，３−プロパンジオール、１，４−ブタンジオール及び２，２−ジメチル−１，３−プロパンジオール（ネオペンチルグリコール）；シクロペンタンジオール、１，４−シクロヘキサンジオール、１，２−シクロヘキサンジメタノール、１，３−シクロヘキサンジメタノール、１，４−シクロヘキサンジメタノール及び２，２，４，４−テトラメチル−１，３−シクロブタンジオール類、及びジエチレングリコール、トリエチレングリコール、ポリエチレングリコール、ポリプロピレングリコール及びポリテトラヒドロフラン、とくには、ジエチレングリコール、トリエチレングリコール及びポリエチレングリコール又はこれらの混合物又は異なる数のエーテル単位を有する化合物が挙げられる。かかる脂肪族ジオールは、異なる脂肪族ジオールの混合物も使用することができる。
【００３３】
本発明に係る芳香族ポリエステル共重合体（ｂ）は、上記脂肪族ジカルボン酸成分、芳香族ジカルボン酸成分及び脂肪族ジオール成分の他に、例えば、５−スルホイソフタル酸のナトリウム塩に代表されるスルホネート基を有するジカルボン酸またはそのエステル形成性誘導体のアルカリ金属塩もしはアルカリ土類金属塩などのスルホネート基含有化合物；グリコリド（１，４−ジオキサン−２，５−ジオン）、Ｄ−、Ｌ−ジラクチド（３，６−ジメチル−１，４−ジオキサン−２，５−ジオン）、ｐ−ヒドロキシ安息香酸などに代表されるグリコール酸、Ｄ−、Ｌ−、Ｄ，Ｌ−乳酸、６−ヒドロキシヘキサン酸及びその環式誘導体、ならびに、例えば３−ポリヒドロキシ酪酸、ポリヒドロキシ吉草酸、ポリラクチドなどに代表されるそのオリゴマーおよびポリマーなどのヒドロキシカルボン酸；２−アミノエタノール、３−アミノプロパノール、４−アミノブタノール、５−アミノペンタノール、６−アミノヘキサノールなどに代表されるアミノ−Ｃ_２〜Ｃ_６−アルカノール、４−アミノメチルシクロヘキサンメタノール、アミノシクロペンタノール、アミノシクロヘキサノールに代表されるアミノ−Ｃ_５〜Ｃ_６−シクロアルカノール、またはこれらの混合物などのアミノ−Ｃ_２〜Ｃ_１２−アルカノールまたはアミノ−Ｃ_５〜Ｃ_１０−シクロアルカノール；１，４−ジアミノブタン、１，５−ジアミノペンタン、１，６−ジアミノヘキサン（ヘキサメチレンジアミン”ＨＭＤ”）などに代表されるジアミノ−Ｃ_１〜Ｃ_８−アルカン；２，２′−ビス（２−オキサゾリン）、ビス（２−オキサゾリニル）メタン、１，２−ビス（２−オキサゾリニル）エタン、１，３−ビス（２−オキサゾリニル）プロパンまたは１，４−ビス（２−オキサゾリニル）ブタン、１，４−ビス（２−オキサゾリニル）ベンゼン、１，２−ビス（２−オキサゾリニル）ベンゼン、１，３−ビス（２−オキサゾリニル）ベンゼンなどに代表される２，２′−ビスオキサゾリン；バリン、ロイシン、イソロイシン、トレオニン、メチオニン、フェニルアラニン、トリプトファン、リシン、アラニン、アルギニン、アスパルテーム酸、システイン、グルタミン酸、グリシン、ヒスチジン、プロリン、セリン、チロシン、アスパラギン、グルタミンに代表される天然のアミノ酸；あるいは、酒石酸、クエン酸、リンゴ酸、トリメチロールプロパン、トリメチロールエタン、ペンタエリトリトール、ポリエーテルトリオール、グリセリン、トリメシン酸、トリメリット酸、無水トリメリット酸、ピロメリット酸、ピロメリット酸二無水物およびヒドロキシイソフタル酸などに代表されるエステルを形成することができる基、例えばヒドロキシル基および／またはカルボキシル基を少なくとも３個有している化合物；トルイレン−２，４−ジイソシアネート、トルイレン−２，６−ジイソシアネート、２，２′−ジフェニルメタンジイソシアネート、２，４′−ジフェニルメタンジイソシアネート、４，４′−ジフェニルメタンジイソシアネート、ナフチレン−１，５−ジイソシアネートまたはキシリレン−ジイソシアネート、トリ（４−イソシアノフェニル）メタンなどの芳香族ジイソシアネート、ｎ−ヘキサメチレンジイソシアネートなどの脂肪族ジイソシアネートなどのイソシアネート化合物；及び、１，４−ブタンジオール−ジビニルエーテル、１，６−ヘキサンジオール−ジビニルエーテル、１，４−シクロヘキサンジメタノール−ジビニルエーテルなどのジビニルエーテルなどの鎖延長剤等を共重合成分として含んでいてもよい。
かかる芳香族ポリエステル共重合体（ｂ）は種々公知の方法で製造し得る。具体的な重合方法としては、例えば、特表２００２−５２７６４４公報、特表２００１−５０１６５２公報に記載されている。又、芳香族ポリエステル共重合体（ｂ）としては、例えば、ＢＡＳＦ社から商品名ＥＣＯＦＬＥＸ（登録商標）として販売されている。
【００３４】
ポリ乳酸系重合体（ｃ）
本発明の生分解性ポリエステル組成物に任意成分として添加されるポリ乳酸系重合体（ｃ）としては、ＭＦＲ（ＡＳＴＭ Ｄ−１２３８による。荷重２１６０ｇ、温度１９０℃）が０．１〜１００ｇ／１０分、好ましくは１〜５０ｇ／１０分、特に好ましくは２〜１０ｇ／１０分のものが使用される。
また、ポリ乳酸系重合体（ｃ）の種類としては、Ｄ，Ｌ−ポリ乳酸共重合体であり、好ましくはＤ体含有率が５〜５０％、特に好ましくは１０〜２０％の範囲にあるポリ乳酸共重合体である。ポリ乳酸系重合体（ｃ）としてかかる範囲の共重合体を用いることにより、靭性に富んだ成形品が得られる。
ポリ乳酸系重合体（ｃ）の融点は１６０℃以下、好ましくは非晶質のものである。
ポリ乳酸系重合体（ｃ）を添加することにより、オリゴマーを２０，０００ｐｐｍ以下含む脂肪族ポリエステル共重合体（ａ）を用いた場合には、得られるフィルムからのオリゴマーのブリードアウトを抑制できるという副次的効果を有する。又、ポリ乳酸系重合体（ｃ）は生分解性速度を制御したり物性を調節する目的でも使用される。
【００３５】
生分解性ポリエステル組成物
本発明の生分解性ポリエステル組成物は、前記脂肪族ポリエステル共重合体（ａ）９５〜５０重量％、好ましくは８９〜５５重量％、及び芳香族系ポリエステル共重合体（ｂ）５〜５０重量％、好ましくは１１〜４５重量％の範囲にある。芳香族系ポリエステル共重合体（ｂ）の量が、５重量％未満では、得られるフィルムの耐引裂き性が改良されないおそれがあり、一方、５０重量％を超えると、得られるフィルムのグロスが低下したり、強度が低くなり、且つ少しの応力（外力）で伸びやすいフィルムとなるおそれがある。
又、前記脂肪族ポリエステル共重合体（ａ）としてオリゴマーを２０，０００ｐｐｍ以下含む脂肪族ポリエステル共重合体（ａ）を用いた場合には、芳香族系ポリエステル共重合体（ｂ）を混合することにより、得られるフィルムからのオリゴマーのブリードを抑制する副次的効果を有するが、芳香族系ポリエステル共重合体（ｂ）の混合量が５重量％未満では、その効果が発揮できないおそれがある。
【００３６】
本発明の生分解性ポリエステル組成物は、前記ポリ乳酸系重合体（ｃ）を脂肪族ポリエステル共重合体（ａ）と芳香族系ポリエステル共重合体（ｂ）１００重量部に対して、３０重量部以下、好ましくは５〜２５重量部加えることにより、芳香族系ポリエステル共重合体（ｂ）を加えることに起因するフィルムのグロスの低下を防ぐことができ、又、前記脂肪族ポリエステル共重合体（ａ）としてオリゴマーを２０，０００ｐｐｍ以下含む脂肪族ポリエステル共重合体（ａ）を用いた場合には、得られるフィルムからのブリードを抑制することができるという副次的効果を有する。
【００３７】
添加剤
本発明の生分解性ポリエステル組成物には、必要に応じて添加剤を加えることができる。
添加剤としては種々公知の添加剤、例えば耐熱安定剤、滑剤、ブロッキング防止剤、核剤、光分解剤、生分解促進剤、酸化防止剤、紫外線安定剤、帯電防止剤、抗菌剤、防臭剤、着色剤等を本発明の目的を損なわない範囲で添加しておいてもよい。かかる添加剤としては、具体的には以下のものを例示できる。
【００３８】
滑剤としては、具体的には、炭化水素系、脂肪酸系、高級アルコール系、多価アルコール系、脂肪族アミド系、金属石鹸系、エステル系等、種々公知の滑剤を、生分解性ポリエステル組成物に、樹脂成分に対して（以下、同様。）０．０１〜１重量％添加しておくと、更にスリップ性が改良されたフィルムが得られるので好ましい。これらの中でもエルカ酸アミドとポリエチレングリコールとの併用系にするとフィルム成形時直後とその後の裁断加工時、更には印刷、ラミネート、製袋加工時等の作業性をバランス良く改善することができる。
また、ステアリン酸等の高級脂肪酸と後述の帯電防止剤、特にステアリルジエタノールアミン等のポリオキシエチレンアルキルアミン、グリセリンモノオレート等の、多価アルコールの高級脂肪酸部分エステル等の非イオン系界面活性剤と併用することにより、帯電防止性とスリップ性に優れた生分解性ポリエステル積層フィルムが得られる。
【００３９】
ブロッキング防止剤としては、具体的には、シリカ、タルク、雲母、ゼオライトや更には金属アルコキシドを焼成する等して得た金属酸化物等の無機化合物粒子、ポリメタクリル酸メチル、メラミンホルマリン樹脂、メラミン尿素樹脂、ポリエステル樹脂等の有機化合物粒子等を例示できる。かかる公知のブロッキング防止剤を生分解性ポリエステル組成物に、０．０１〜１重量％添加しておくと、更に耐ブロッキング性が改良されたフィルムが得られるので好ましい。これらの中でも、シリカ、ポリメタクリル酸メチルが耐ブロッキング性、透明性の面から特に好ましい。
かかるブロッキング防止剤の粒子径は０．１〜７μｍのものが好ましい。
【００４０】
帯電防止剤としては、種々公知のもの、例えば、第四級アンモニウム化合物に代表されるカチオン系界面活性剤、アルキルスルホン酸塩に代表されるアニオン系界面活性剤、多価アルコールの部分脂肪酸エステル、脂肪アミンまたは脂肪アミドのエチレンオキサイド付加物等に代表される非イオン系界面活性剤等が挙げられる。更に、具体的には、多価アルコールの部分脂肪酸エステルとしては、グリセリンモノステアレート、グリセリンモノオレート、グリセリンモノラウレート、グリセリンモノパルミテート等のグリセリンモノ脂肪酸エステル、ソルビタンラウレート、ソルビタンパルミテート、ソルビタンステアレート、ソルビタントリオレート等のソルビタン脂肪酸エステル、脂肪アミンまたは脂肪アミドのエチレンオキサイド付加物としては、ポリオキシエチレンラウリルアミン、ポリオキシエチレン牛脂アミン、ステアリルジエタノールアミン等が挙げられる。かかる帯電防止剤の生分解性ポリエステル組成物に対する添加量は、通常、０．０１〜１重量％の範囲にある。
【００４１】
脂肪族ポリエステル共重合体（ａ）、芳香族系ポリエステル共重合体（ｂ）、必要に応じて加えられるポリ乳酸系重合体（ｃ）、及び／又は添加剤との混練方法は、一般的な方法が好ましく使用でき、具体的には原料樹脂ペレットや粉体、固体の細片等をヘンシェルミキサーやリボンミキサーで乾式混合し、単軸や２軸の押出機、バンバリーミキサー、ニーダー、ミキシングロールなどの公知の溶融混合機に供給して溶融混練することができる。
【００４２】
本発明の生分解性ポリエステルフィルムは、上記で得られた混練物をＴ−ダイフィルム成形方法、インフレーションフィルム成形方法、カレンダーフィルム成形方法、押出ラミネートフィルム成形方法等により成形して得られる。
【００４３】
本発明の生分解性ポリエステルフィルムは、厚みが５〜５００μｍ、好ましくは１０〜１００μｍである。
【００４４】
前記脂肪族ポリエステル共重合体（ａ）としてオリゴマーを２０，０００ｐｐｍ以下含む脂肪族ポリエステル共重合体（ａ）を用いた場合には、上記で得られたフィルムを、アニール処理を行うことにより、更にオリゴマーのブリードアウトを効果的に抑制することができる。
アニール処理温度としては、芳香族系ポリエステル共重合体（ｂ）あるいは必要に応じて加えられるポリ乳酸系重合体（ｃ）の量（組成比）にもよるが、通常、３０〜６０℃、好ましくは３５〜５０℃、さらに好ましくは３５〜４５℃の範囲にある。アニール処理温度が３０℃未満では、オリゴマーのブリードアウトの更なる抑制効果は認められない場合があり、６０℃より高すぎるとフィルムが軟かくなりすぎてブロッキングするおそれがある。
アニール処理時間としては、温度にもよるが、通常、１０時間以上、好ましくは２４〜４８０時間、さらに好ましくは７２〜３６０時間である。アニール処理時間が１０時間未満では、オリゴマーの更なるブリードアウトの抑制効果が発現しないおそれがある。上限は特には限定されないが、４８０時間を超えると抑制効果の発現が飽和する。
【００４５】
本発明のフィルムは、次の特徴を有する。
光学特性として、ヘーズ（ＨＺ）：３０％以下、好ましくは２５％以下である。
光学特性として、平行光線透過率（ＰＬＴ）：６０％以上、好ましくは６５％以上である。
グロス：３０％以上、好ましくは５０％以上である。
引裂強度（ＭＤ、ＴＤとも）：１１０ｍＮ以上、好ましくは１２０ｍＮ以上である。
ヤング率（ＭＤ、ＴＤとも）：２００〜１０００ＭＰａ、好ましくは３００〜８００ＭＰａの範囲にある。
引張り強さ（ＭＤ）：３０ＭＰａ以上、好ましくは４０ＭＰａ以上である。
引張り強さ（ＴＤ）：１５ＭＰａ以上、好ましくは３０ＭＰａ以上である。
伸び（ＭＤ）：５０％以上である。
伸び（ＴＤ）：５０％以上である。
降伏点応力（ＭＤ）：１５ＭＰａ以上、好ましくは２０ＭＰａ以上である。
降伏点応力（ＴＤ）：１０ＭＰａ以上、好ましくは２０ＭＰａ以上である。
【００４６】
本発明のフィルムとしては、シート、フィルム、テープを含む。またフィルムは単層でも用いられるが、他の基材との積層体であってもよい。積層フィルムを得る場合には、本発明の生分解性ポリエステル組成物から得られるフィルムと他の基材とを多層ダイを用いて共押出フィルムとしてよい。また予め得られた基材に該組成物を押出しラミネートして積層フィルムとしてもよいし、あるいは夫々別個に得たフィルム等を貼り合わせて積層フィルムとしてもよい。尚、基材としてはポリ乳酸、脂肪族ポリエステル、芳香族ポリエステルから得られるフィルム、シート、カップ、トレー状物、あるいはその発泡体、ガラス、金属、アルミニウム箔、紙等が挙げられる。基材が熱可塑性樹脂からなるフィルムの場合は、無延伸であっても一軸あるいは二軸延伸フィルムであってもよい。勿論、基材は１層でも２層以上としてもよい。
本発明のフィルムは透明性に優れており、２次成形して宅配物及び郵便物搬送用の溶断シール包装体、精密部品、パソコン、家電製品、車シート等の保護フィルム、食品用、特に野菜や乾物、菓子類とくにスナック菓子類、衣料、医薬品、カセットやビデオテープ等の各種包装用、及び分解性ゴミ袋、水切り袋、孔あきフィルム、農業用マルチ（防草）フィルム、植生フィルム、ベタ掛けフィルム、根巻きシート、排水シート、養生シート、緩衝シート、緩衝材、カード等に加工することができる。
【００４７】
本発明のフィルムは、ヒートシール性、溶断シール強度に優れるので上記のように一般の包装用フィルムとして有用であるが、中でも、溶断シールを伴なう溶断シール包装用フィルムとして、特に雑誌等の重量物の溶断シール包装用フィルムとして好適に用い得る。
又、本発明のフィルムは、包装袋の形状で使用することもできる。その際、包装袋の口部に、前記芳香族系ポリエステル共重合体（ｂ）からなるチャック（ファスナー、ジッパー）を接合することにより、開閉が容易な包装袋とすることができる。
【００４８】
【実施例】
以下、実施例により本発明を具体的に説明するが、本発明はこれらに限定されるものではない。
【００４９】
フィルム原料
（ａ）脂肪族ポリエステル共重合体
ＰＣＢＳ−１１：ダイセル化学工業（株）社製、コハク酸−１，４−ブタンジオール−ε−カプロラクトン三元共重合体、カプロラクトン含有量４モル％、Ｍｗ２２万（ＧＰＣ測定における標準ポリスチレン換算分子量）、ＭＦＲ（１９０℃、荷重２１６０ｇ）０．９ｇ／１０分、Ｔｍ１０４℃、密度１．２４ｇ／ｃｍ^３、オリゴマー含有率６９００重量ｐｐｍ。
（ｂ）芳香族系ポリエステル共重合体
ＰＢＡ／Ｔ：ＢＡＳＦ社製、商品名ＥＣＯＦＬＥＸ（登録商標）、アジピン酸−テレフタル酸−１，４−ブタンジオール（テレフタル酸４６モル％、アジピン酸５４モル％）、ＭＦＲ（１９０℃、荷重２１６０ｇ）３ｇ／１０分、Ｔｍ１１２℃、密度１．２６ｇ／ｃｍ^３。
（ｃ）ポリ乳酸系重合体
ＰＬＡＣ：三井化学（株）社製、ポリ乳酸共重合体、Ｄ−乳酸含有量１１％、ＭＦＲ（１９０℃、荷重２１６０ｇ）２．６ｇ／１０分、非晶性、Ｔｇ５５℃。
【００５０】
樹脂添加剤
エルカ酸アミド（ＥＡ）：チバスペシャルティケミカルズ社製、商品名ＡＴＭＥＲ ＳＡ１７５３
シリカ（ＳＩ）：富士シリシア化学社製、商品名サイリシア７３０（粒径４μｍ）
上記を樹脂組成物中に、樹脂分に対してそれぞれ１０００重量ｐｐｍ添加した。
【００５１】
本発明における各種測定方法は以下の通りである。
（１）オリゴマー含有率（ｐｐｍ）：上記ポリマーのＧＰＣ測定において、クロロホルム溶媒にて標準ポリスチレン換算分子量５００以下のものの、全体に対する面積比率で求めた。
（２）ブリードアウトの官能評価：無延伸フィルムの表面を指先でこすり、指への付着の程度で評価した。付着が殆どないものを○、付着が微少あるものを△、付着が多く明らかに通常の用途に使用不可のものを×で表した。
（３）ヘーズ（ＨＺ）：日本電色工業製ＮＤＨ−３００Ａを使用して、無延伸フィルムのくもり度を測定した。測定値は５回の平均値である。
（４）平行光線透過率（ＰＬＴ）：日本電色工業製ＮＤＨ−３００Ａを使用して、無延伸フィルムの平行光線透過率を測定した。測定値は５回の平均値である。
（５）引張り特性：試験片として、無延伸フィルムからＭＤ方向又はＴＤ方向の短冊状フィルム片（長さ１５０ｍｍ、巾１５ｍｍ）を採取して、チャック間距離１００ｍｍで、引張試験を行い、降伏点及び破断点における強度（応力）（ＭＰａ）、伸び（％）、ヤング率（ＭＰａ）を求めた。なお、伸び（％）はチャック間距離の変化とした。
測定条件は以下の通りである。
使用機器：オリエンテック社製テンシロン万能試験機ＲＴＣ−１２２５
クロスヘッドスピード：３００ｍｍ／分（但し、ヤング率の測定は５ｍｍ／分で行った。）
測定値は５回の平均値である。
（６）溶断シール強度
無延伸フィルムを使用して、溶断式連続製袋機にて、速度５０００セット／時でＡ４大ノートを自動充填して評価した。上下部分（流れ方向を上とした）の溶断シールは角度９０°の溶断刃を３１０℃に加熱し、背貼り部分は半月型の鏝を３００℃に加熱してシールした。
得られた包装袋の上部、下部および背貼り部から幅１５ｍｍのサンプルを切り出し、溶断シール部の強度をオリエンテック社製テンシロン万能試験機ＲＴＣ−１２２５を用いて、３００ｍｍ／分の引張り速度で引張り、最大強度を溶断シール強度とした。
（７）ヒートシール強度
ＰＬＡＣ−２からなる延伸倍率３．０×３．０、厚さ２５μｍの二軸延伸フィルムにウレタン系接着剤（武田薬品工業製：商品名タケラックＡ９６８（２０％）＋タケラックＡ８（２０％）＋酢酸エチル（６０％））を用い、無延伸フィルムをドライラミネートして厚さ５７〜５８μｍの積層フィルムを得た。
得られた積層フィルムの無延伸フィルム面を重ね合わせて、テスター産業株式会社製ＴＰ−７０１−Ｂ ＨＥＡＴＳＥＡＬＴＥＳＴＥＲを用いて、所定の温度で、シール面圧１ｋｇ／ｃｍ^２、１秒の条件下で熱融着（ヒートシール）した。尚、加熱は上側のみとした。次いで、熱融着した積層フィルムをオリエンテック社製テンシロン万能試験機ＲＴＣ−１２２５を用いて幅１５ｍｍの熱融着したサンプルを３００ｍｍ／分の引張り速度で剥離し、その最大強度をヒートシール強度とした。
【００５２】
［実施例１〜４、比較例１および２］
上記脂肪族ポリエステル共重合体（ａ）及び芳香族系ポリエステル共重合体（ｂ）を表１に示す割合で、予め溶融混練して生分解性ポリエステル組成物を得た。
上記で得た生分解性ポリエステル組成物を用い、Ｔ−ダイフィルム成形機を使用して厚さ３０μｍの無延伸フィルムを得た。
フィルムの評価結果を表１に示す。
【００５３】
【表１】

【００５４】
表１から明らかなように、生分解性ポリエステル組成物における芳香族系ポリエステル共重合体（ｂ）の量を増すことにより無延伸フィルムの引裂強度が大幅に改良されることが分る（実施例１〜４、比較例１）。
又、脂肪族ポリエステル共重合体（ａ）から得られる無延伸フィルムはオリゴマーのブリードアウトが生じる（比較例１）のに対し、芳香族系ポリエステル共重合体（ｂ）を添加することによりオリゴマーのブリードアウトが抑制されることが分る（実施例１〜４）。
【００５５】
［実施例５〜９、および参考例１〜３］
上記脂肪族ポリエステル共重合体（ａ）、芳香族系ポリエステル共重合体（ｂ）及び乳酸系重合体（ｃ）を表２に示す割合で、予め溶融混練して生分解性ポリエステル組成物を得た。
上記で得た生分解性ポリエステル組成物を用い、Ｔ−ダイフィルム成形機を使用して厚さ３０μｍの無延伸フィルムを得た。フィルムの評価結果を表２に示す。
【００５６】
【表２】

【００５７】
表２から明らかなように、脂肪族ポリエステル共重合体（ａ）と芳香族系ポリエステル共重合体（ｂ）からなる生分解性ポリエステル組成物に乳酸系重合体（ｃ）を加えた生分解性ポリエステル組成物から得られる無延伸フィルムは、グロスが優れることが分る（実施例６と実施例２、及び実施例５と実施例７との比較）。
又、脂肪族ポリエステル共重合体（ａ）から得られる無延伸フィルムはオリゴマーのブリードアウトが生じる（比較例１）のに対し、芳香族系ポリエステル共重合体（ｂ）と乳酸系重合体（ｃ）を添加することによりオリゴマーのブリードアウトが抑制されることが分る（実施例５〜８）。
【００５８】
［実施例１０、１１］
実施例７で得られた無延伸フィルムに、厚さ２５μｍの二軸延伸ポリ乳酸フィルムをウレタン系接着剤（武田薬品工業製：商品名タケラックＡ９６８（２０％）＋同Ａ８（２０％）＋酢酸エチル（６０％））を用いラミネートして積層フィルムを作成した。該積層フィルムは所定の大きさに切断した積層フィルム片を、幅方向に二つ折りにして、下部及び側部となる部分を溶断シールして、上部に開口部を有する包装袋とした。
別途、前記ＰＢＡ／Ｔ樹脂を使用して、噛み合ってチャックとなる凸状部を有する帯と凹状部を有する帯を作成した。
上記積層フィルム片の上部となる部分の無延伸フィルム面側に、上記凸状部を有する帯と凹状部を有する帯を、それぞれ熱融着させてチャック付き積層フィルム片を得、幅方向に二つ折りにして、下部及び側部となる部分を溶断シールして、上部にチャック付き開口部を有する包装袋とした。該包装袋のチャックを繰り返し開閉したが、チャック部は、しなやかであり、また積層フィルムから剥がれることはなかった。
【００５９】
【発明の効果】
本発明によれば、透明性の良好な生分解性ポリエステルフィルム、特に溶断シール強度、ヒートシール強度、引き裂き強度に優れており、柔軟で溶断シール包装等の自動充填包装用フィルムとして好適な生分解性ポリエステルフィルムが得られる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a biodegradable polyester composition which is flexible and is suitable for obtaining a film for automatic filling and packaging such as fusing seal packaging having excellent tear strength, heat sealability and fusing seal strength, and a biodegradable polyester film comprising the same. And packaging bags.
[0002]
[Prior art]
As a plastic that can be biodegraded in the natural environment, versatile aliphatic polyesters are attracting attention. Polylactic acid (PLA), polybutylene succinate (PBS), polyethylene succinate (PES), polycaprolactone (PCL) And the like are on the market, and the use thereof is as a packaging film.
Among the aliphatic polyesters described above, PLA is a stretched or highly crystallized film or molded product, and if it is high, it has a melting point around 170 ° C. and has high heat resistance. The degree is low and the unstretched thin film is not practical for packaging. In addition, the film of PLA alone has a slow biodegradability. Although PBS and PES have sufficient heat resistance at a melting point of around 100 ° C., they have a low biodegradation rate, are not practically sufficient, and lack flexibility in mechanical properties. Although PCL is excellent in flexibility, its use is limited due to its low melting point of 60 ° C. and low heat resistance, but its biodegradation rate is very fast.
[0003]
As described above, the aliphatic polyester homopolymer has various limitations in use as a film. For example, an aliphatic polyester copolymer such as a polybutylene succinate-polycaprolactone copolymer described in Japanese Patent No. 2997756 is used. By introducing a caprolactone unit into it, practical flexibility and appropriate biodegradability can be realized, and by controlling the content of the caprolactone unit, the melting point can be raised to 80 ° C or higher and sufficient heat resistance can be achieved. It has been found that it is possible to maintain biodegradability and control biodegradability (Patent Document 1).
[0004]
WO 02-44249 discloses a weight-average molecular weight of 40 synthesized by a polycondensation reaction of a mixture of three components of an aliphatic diol, an aliphatic dicarboxylic acid, and an aliphatic hydroxycarboxylic acid or an anhydrous cyclic compound thereof (lactones). It is disclosed that the use of a high molecular weight aliphatic polyester copolymer having a molecular weight of 2,000 or more and another biodegradable resin has good molecular weight stability at the time of forming a film or the like and good molding (Patent Reference 2).
[0005]
Although the film for packaging using the above resin is excellent in transparency and flexibility, at the time of fusing seal packaging, the fusing seal portion in the MD direction, that is, the center seal portion becomes thin and melts, and recrystallization due to solidification occurs and becomes brittle. For this reason, the strength at the fusing seal portion is small, and it is not suitable for packaging heavy objects such as printed materials such as magazines.
[0006]
[Patent Document 1]
Patent No. 2997756 (Claims 1 to 3, Examples 1 to 5)
[Patent Document 2]
WO 02-44249 (Claims, last paragraph of the Summary of the Invention, Table VII-1)
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a biodegradable polyester film having good transparency, particularly a tear strength and an excellent fusing seal strength, and a flexible and suitable biodegradable polyester film as an automatic filling packaging film such as a fusing seal packaging. An object of the present invention is to provide a biodegradable polyester composition used for the composition.
[0008]
[Means for Solving the Problems]
The present inventors comprise, for example, an aliphatic polyester copolymer (a) composed of a specific aliphatic dicarboxylic acid-aliphatic diol-aliphatic lactone and an aliphatic dicarboxylic acid-aromatic dicarboxylic acid-aliphatic diol. It has been found that such a problem can be solved by using a composition comprising the aromatic polyester copolymer (b), and the present invention has been completed.
[0009]
That is, in the first aspect of the present invention, a molecular chain is a repeating unit represented by the following general formulas (1) to (3):
-CO-R ¹ -CO- (1)
(Where R ¹ Represents a divalent aliphatic group having 1 to 12 carbon atoms. )
-OR ² -O- (2)
(Where R ² Represents a divalent aliphatic group having 2 to 12 carbon atoms. )
A repeating unit represented by the following general formula (3):
-CO-R ³ -O- (3)
(Where R ³ Represents a divalent aliphatic group having 1 to 10 carbon atoms. )
And a repeating unit (3) of 1 to 25 mol% (in the general formulas (1) to (3), the amounts of the repeating units (1) and (2) are substantially equal, and the repeating units (1) and (2) And the total amount of (3) is 100 mol%), and 95 to 50% by weight of an aliphatic polyester copolymer (a) having a weight average molecular weight of 40,000 or more, and
The molecular chain is a repeating unit represented by the following general formulas (4) to (6):
-CO-R ⁴ -CO- (4)
(Where R ⁴ Represents a divalent aliphatic group having 0 to 8 carbon atoms. )
-CO-R ⁵ -CO- (5)
(Where R ⁵ Represents a divalent aromatic group having 8 to 12 carbon atoms. )
-OR ⁶ -O- (6)
(Where R ⁶ Represents a divalent aliphatic group having 2 to 12 carbon atoms. )
And 20 to 95 mol% of the repeating unit (4) and 80 to 5 mol% of the repeating unit (5) (the total of the repeating units (4) and (5) is 100 mol%, and the repeating units (4) and (4) 5) and 5 to 50% by weight of the aromatic polyester copolymer (b) (where the total of (a) and (b) is 100% by weight). %).) A biodegradable polyester composition characterized by comprising:
A second aspect of the present invention is that the aliphatic polyester copolymer (a) is a low molecular weight aliphatic polyester copolymer having a weight average molecular weight of 5,000 or more, which is a polymerization intermediate of the aliphatic polyester copolymer (a). (A ′) The biodegradable polyester composition according to the first aspect of the present invention, which is obtained by reacting 0.1 to 5 parts by weight of a diisocyanate compound with 100 parts by weight to increase the molecular weight.
A third aspect of the present invention is that the polylactic acid-based polymer (c) is not more than 30 parts by weight based on 100 parts by weight of the composition of the aliphatic polyester copolymer (a) and the aromatic polyester copolymer (b). A biodegradable polyester composition according to the first or second aspect of the present invention, which is added.
A fourth aspect of the present invention provides the biodegradable polyester composition according to any one of the first to third aspects of the present invention, wherein the general formula (1) is a succinic acid residue and / or an adipic acid residue. I do.
A fifth aspect of the present invention is the biodegradable polyester according to any one of the first to fourth aspects of the present invention, wherein the general formula (2) is an ethylene glycol residue and / or a 1,4-butanediol residue. A composition is provided.
A sixth aspect of the present invention provides the biaxially stretched laminated film according to any one of the first to fifth aspects of the present invention, wherein the general formula (3) is a ring-opened group of ε-caprolactone.
A seventh aspect of the present invention provides the biodegradable polyester composition according to any one of the first to sixth aspects, wherein the general formula (4) is an adipic acid residue or a succinic acid residue. An eighth aspect of the present invention provides the biodegradable polyester composition according to any one of the first to seventh aspects, wherein the general formula (5) is a terephthalic acid residue.
A ninth aspect of the present invention is the biodegradable polyester according to any one of the first to eighth aspects of the present invention, wherein the general formula (6) is an ethylene glycol residue and / or a 1,4-butanediol residue. A composition is provided.
A tenth aspect of the present invention is the biodegradable polymer according to any one of the first to ninth aspects of the present invention, wherein the polylactic acid-based polymer (c) is a polylactic acid copolymer containing 5 to 50% of a D-form. A polyester composition is provided.
An eleventh aspect of the present invention provides a biodegradable polyester film obtained from the biodegradable polyester composition according to any one of the first to tenth aspects of the present invention.
A twelfth aspect of the present invention provides a packaging film comprising the biodegradable polyester film according to the eleventh aspect of the present invention.
According to a thirteenth aspect of the present invention, there is provided a packaging bag comprising the packaging film according to the twelfth aspect of the present invention.
A fourteenth aspect of the present invention provides the packaging bag according to the thirteenth aspect, wherein the packaging bag is a fusing seal packaging bag.
A fifteenth aspect of the present invention is any one of the thirteenth and fourteenth aspects of the present invention, wherein a chuck made of the aromatic polyester copolymer (b) according to the first aspect of the present invention is joined to a mouth of a packaging bag. Is provided.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
In the high molecular weight aliphatic polyester copolymer (a) according to the present invention, the molecular chain is composed of the repeating units represented by the general formulas (1) to (3), and the amount of the repeating units (1) and (2) However, 49.5 to 37.5 mol% each, the amount of the repeating unit (3) is 1 to 25 mol% (the amounts of the repeating units (1) and (2) are substantially equal, and (1), ( The sum of the amounts of 2) and (3) is 100 mol%), and the weight average molecular weight is 40,000 or more, usually in the range of 70,000 to 350,000, preferably 100,000 to 250,000. It is.
[0011]
When the amount of the repeating unit (3) is less than 1 mol%, the obtained polymer has high crystallinity and is inflexible and hard, and the biodegradability is slow and insufficient. On the other hand, if it is more than 25 mol%, the resulting polymer has a low melting point and extremely low crystallinity, so that it has no heat resistance and is not suitable for practical use.
The amount of the repeating unit (3) in the high molecular weight aliphatic polyester copolymer (a) is 1 to 25 mol%, preferably 1 to 15 mol%, more preferably 1 to 12 mol%, and particularly preferably 1 to 12 mol%. 10 mol%.
Two or more aliphatic polyester copolymers (a) may be mixed and used.
[0012]
The high molecular weight aliphatic polyester copolymer (a) as described above also has the above composition, and the low molecular weight aliphatic polyester copolymer (a ′) having a weight average molecular weight of 5,000 or more is the copolymer. It may be linked by 0.1 to 5 parts by weight of a diisocyanate compound with respect to 100 parts by weight of the compound (a ') so that the weight average molecular weight becomes 40,000 or more.
[0013]
(A) component
The component (A) that gives the aliphatic dicarboxylic acid residue of the formula (1) includes an aliphatic dicarboxylic acid, an anhydride thereof, or a mono- or diester thereof, and is represented by the following general formula (1 ′). .
R ¹⁴ -OCO-R ¹ -COO-R ^Fifteen (1 ')
(Where R ¹ Is a divalent aliphatic group having 1 to 12 carbon atoms, R ¹⁴ And R ^Fifteen Represents a hydrogen atom or an aliphatic or aromatic group having 1 to 6 carbon atoms. R ¹⁴ And R ^Fifteen May be the same or different. )
R ¹ The divalent aliphatic group represented by is preferably a chain or cyclic alkylene group of 2 to 8, and-(CH ₂ ) ₂ -,-(CH ₂ ) ₄ -,-(CH ₂ ) ₆ And a linear lower alkylene group having 2 to 6 carbon atoms such as-.
[0014]
R ¹⁴ And R ^Fifteen Represents an aliphatic dicarboxylic acid when is a hydrogen atom. As the aliphatic dicarboxylic acid, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, suberic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, sebacic acid, diglycolic acid, ketopimelic acid, malonic acid, methylmalon Acids and the like.
R ¹⁴ And R ^Fifteen Examples of the aliphatic group represented by include a linear or branched alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and a cycloalkyl group having 5 to 12 carbon atoms such as a cyclohexyl group. .
R ¹⁴ And R ^Fifteen Examples of the aromatic group represented by include a phenyl group and a benzyl group.
Above all, R ¹⁴ And R ^Fifteen Is a lower alkyl group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. Examples of such a dialkyl ester include dimethyl succinate, diethyl succinate, dimethyl glutarate, diethyl glutarate, dimethyl adipate, diethyl adipate, dimethyl pimerate, dimethyl azelate, dimethyl suberate, diethyl suberate, Examples include dimethyl sebacate, diethyl sebacate, dimethyl decanedicarboxylate, dimethyl dodecanedicarboxylate, dimethyl diglycolate, dimethyl ketopimelate, dimethyl malonate, and dimethyl methylmalonate. These may be used alone or in combination of two or more.
[0015]
(B) component
Examples of the component (B) that provides the aliphatic diol residue of the formula (2) include an aliphatic diol.
The aliphatic diol is represented by the following general formula (2 ′).
HO-R ² -OH (2 ')
(Where R ² Represents a divalent aliphatic group having 2 to 12 carbon atoms. )
Examples of the divalent aliphatic group include a chain or cyclic alkylene group having 2 to 12, preferably 2 to 8 carbon atoms. Preferred alkylene groups are-(CH ₂ ) ₂ -,-(CH ₂ ) ₃ -,-(CH ₂ ) ₄ And a straight-chain lower alkylene group having 2 to 6 carbon atoms such as-.
Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 2-methyl-propanediol, 1,4-butanediol, neopentyl glycol, Pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, dodecamethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, Pentaethylene glycol, polyethylene glycol having a molecular weight of 1000 or less can be used. These may be used alone or in combination of two or more.
[0016]
(C) component
The component (C) that gives the aliphatic hydroxycarboxylic acid residue of the formula (3) includes a hydroxycarboxylic acid or a hydroxycarboxylic acid ester represented by the following general formula (3 ′), or a compound represented by the following general formula (3 ″). The lactones represented are mentioned.
R ¹⁶ OCO-R ³ -OH (3 ')
(Where R ³ Is a divalent aliphatic group having 1 to 10 carbon atoms, R ¹⁶ Represents a hydrogen atom or an aliphatic or aromatic group having 1 to 6 carbon atoms. )
[0017]
Embedded image

[0018]
(Where R ³ Represents a divalent aliphatic group having 1 to 10 carbon atoms. )
In the formula (3 ′), the divalent aliphatic group R ³ Examples thereof include a chain or cyclic alkylene group having 2 to 10, preferably 2 to 8 carbon atoms. R ¹⁶ Is hydrogen, or an aliphatic or aromatic group. Examples of the aliphatic group include a linear or branched lower alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms such as a cyclohexyl group, and an aromatic group. Phenyl group, benzyl group and the like.
[0019]
Examples of the hydroxycarboxylic acid include glycolic acid, L-lactic acid, D-lactic acid, D, L-lactic acid, 2-methyllactic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, and 2-hydroxylactic acid. Examples thereof include hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxy-3-methylbutyric acid, hydroxypivalic acid, hydroxyisocaproic acid, and hydroxycaproic acid.
The hydroxycarboxylic acid may be a cyclic dimer ester (lactide) having two molecules bonded thereto. Specific examples thereof include glycolide obtained from glycolic acid, and those obtained from lactic acid.
Examples of the hydroxycarboxylic acid ester include the above-mentioned hydroxycarboxylic acid methyl ester, ethyl ester and the like, and acetic acid ester and the like.
[0020]
Examples of the lactones include those represented by the general formula (3 ″).
Divalent aliphatic group R in formula (3 ″) ³ Examples thereof include a linear or branched alkylene group having 4 to 10 carbon atoms, preferably 4 to 8 carbon atoms.
Specific examples of lactones include, for example, β-propiolactone, β-butyrolactone, γ-butyrolactone, β-valerolactone, δ-valerolactone, δ-caprolactone, ε-caprolactone, 4-methylcaprolactone, 3,5 Methylated caprolactone such as 3,5-trimethylcaprolactone, 3,3,5-trimethylcaprolactone; cyclic monomeric esters of hydroxycarboxylic acids such as β-methyl-δ-valerolactone, enantholactone, laurolactone; glycolide, L And cyclic dimer esters of the above hydroxycarboxylic acids such as -lactide and D-lactide. Among them, ε-caprolactone is preferred. These may be used as a mixture of two or more monomers.
[0021]
When the low molecular weight aliphatic polyester copolymer (a ') is synthesized by a polymerization reaction of the three components (A), (B) and (C), the synthesis step depends on the type of the raw material used, for example, It can be divided into an esterification step in which the first half of the dehydration reaction mainly proceeds, and a polycondensation step in which the second half of the ester exchange reaction mainly proceeds.
The esterification step is performed at a reaction temperature of 80 ° C. to 250 ° C., preferably 100 ° C. to 240 ° C., more preferably 145 ° C. to 230 ° C., for 0.5 to 5 hours, preferably 1 to 4 hours, at 760 to 100 Torr. It is desirable to do it below. The catalyst is not always required, but is added to 10 moles of the aliphatic dicarboxylic acid or diester used as a raw material. ^-7 -10 ^-3 Mole, preferably 10 ^-6 ~ 5 × 10 ^-4 It may be used in molar amounts.
The latter half polycondensation step is desirably completed in 2 to 10 hours, preferably 3 to 6 hours by raising the reaction temperature while depressurizing the reaction system, and finally 180 to 270 ° C., preferably 190 ° C. At a reaction temperature of up to 240 ° C., the degree of pressure reduction is preferably 3 Torr or less, more preferably 1 Torr or less. In this step, it is preferable to use a general transesterification catalyst, and 10 mols per 1 mol of the aliphatic dicarboxylic acid or diester used as a raw material is used. ^-7 -10 ^-3 Mole, preferably 10 ^-6 ~ 5 × 10 ^-4 Used in molar amounts. If the amount of the catalyst is less than this range, the reaction does not proceed well, and the reaction takes a long time. On the other hand, if it exceeds this range, it causes thermal decomposition, cross-linking, coloring and the like of the polymer at the time of polymerization, and also causes thermal decomposition and the like in molding of the polymer, which is not preferable.
In the synthesis step, examples of the catalyst that can be used in both the esterification step in which the dehydration reaction mainly proceeds and the polycondensation step in which the second half transesterification reaction mainly proceeds include the following specific examples. These catalysts may be used alone or in combination of two or more.
As the catalyst, those described in WO 02-44249 can be used.
[0022]
In the step of synthesizing the aliphatic polyester copolymer (a) or (a ′), the feed ratio of the raw materials (A) and (B) should be selected so as to satisfy the following conditional expression (i). Is desirable.
1.0 ≦ [B] / [A] ≦ 2.0 (i)
(In the formula, [A] represents the number of moles of the component (A), and [B] represents the number of moles of the component (B).)
When the value of [B] / [A] is less than 1, not only is it difficult to obtain an aliphatic polyester copolymer having a desired molecular weight, but also the proportion of carboxylic acid terminals in the aliphatic polyester copolymer to be produced is high. Therefore, they are susceptible to hydrolysis reaction. Further, as the value of [B] / [A] becomes larger than 2, the proportion of the carboxylic acid terminal of the resulting aliphatic polyester copolymer becomes smaller, so that a product having excellent hydrolysis resistance can be obtained. In order to increase the amount of the component (B) to be removed in order to obtain a high molecular weight substance, a long-time reaction is required.
In the present invention, in order to finally obtain an aliphatic polyester copolymer (a) having a practical film strength, a diisocyanate compound is added to a low molecular weight aliphatic polyester copolymer (a ′) in a molten state to obtain a weight. The average molecular weight may be increased to 40,000 or more.
[0023]
The diisocyanate compound is preferably an aliphatic diisocyanate compound. Specifically, hexamethylene diisocyanate, lysine diisocyanate methyl ester {OCN- (CH ₂ ) ₄ -CH (-NCO) (-COOCH ₃ ), Trimethylhexamethylene diisocyanate and the like are exemplified, and among them, hexamethylene diisocyanate is preferable. The aliphatic polyester copolymer containing a urethane bond has the same weight average molecular weight as that of the copolymer (a), but is 40,000 or more, usually 70,000 to 350,000, preferably 100,000. 2,000 to 250,000.
[0024]
In the above, it is preferable that the charging ratios of the raw materials (A), (B) and (C) are selected so as to satisfy the following conditional expression (ii ′).
0.01 ≦ [C] / ([A] + [B] + [C]) ≦ 0.25 (ii ′)
(In the formula, [A], [B], and [C] indicate the numbers of moles of the components (A), (B), and (C), respectively).
[C] / ([A] + [B] + [C]) in the above formula is the molar fraction of the component (C) contained in the aliphatic polyester copolymer (a) or (a ′). Represent.
The molar fraction of the component (C) is preferably 0.015 to 0.15, more preferably 0.025 to 0.12, and particularly preferably 0.025 to 0.10.
[0025]
The aliphatic polyester copolymer (a) has a weight average molecular weight of 40,000 or more, usually 70,000 to 350,000, preferably 100,000 to 250,000.
The melting point of the aliphatic polyester copolymer (a) is preferably 85 to 120C, more preferably 90 to 110C. Further, the difference between the melting point and the decomposition temperature is as large as 100 ° C. or more, and thermoforming is easy.
In the above aliphatic polyester copolymer, particularly, R in the above general formulas (1) to (3) ¹ And R ² Is (CH ₂ ) ₂ Or (CH ₂ ) ₄ And R ³ Is (CH ₂ ) ₅ Are those having a high melting point and high crystallinity.
[0026]
The aliphatic polyester copolymer (a) may contain an oligomer having a molecular weight of 500 or less. In this case, the content is adjusted to 20,000 ppm or less, preferably 15,000 ppm or less, and particularly 10,000 ppm or less. Need to be kept.
[0027]
Aromatic polyester copolymer (b)
The aromatic polyester copolymer (b) according to the present invention comprises the repeating units represented by the general formulas (4) to (6).
In the aromatic polyester copolymer (b), the repeating unit (4), which is an aliphatic dicarboxylic acid residue, accounts for 20 to 95 mol%, preferably 30 to 70 mol%, more preferably 40 to 60 mol%. And the repeating unit (5), which is an aromatic dicarboxylic acid residue, accounts for 5 to 80 mol%, preferably 70 to 30 mol%, more preferably 60 to 40 mol%, and is an aliphatic diol residue. The repeating unit (6) is substantially equal to the sum of the aliphatic dicarboxylic acid residue and the aromatic dicarboxylic acid residue.
[0028]
The aromatic polyester copolymer (b) has a melting point in the range of preferably 50 to 200C, more preferably 70 to 170C, and particularly preferably 100 to 160C. The MFR of the aromatic polyester copolymer (b) (at 190 ° C. under a load of 2160 g according to ASTM D-1238) is a composition with the aliphatic polyester copolymer (a) and is particularly limited as long as a film can be formed. Although not limited, it is usually in the range of 0.1 to 100 g / 10 min, preferably 0.2 to 50 g / 10 min, and more preferably 0.5 to 20 g / 10 min.
[0029]
Examples of the aliphatic dicarboxylic acid or the ester-forming derivative thereof which gives the repeating unit (4) include the following.
The aliphatic dicarboxylic acids generally have 2 to 10 carbon atoms (including the carbon of the carboxyl group), especially 4 to 6 carbon atoms. The dicarboxylic acid may be linear, branched, or cyclic (alicyclic). The cyclic aliphatic dicarboxylic acids are typically those having 7 to 10 carbon atoms, especially those having 8 carbon atoms. As long as the main component is an aliphatic dicarboxylic acid having 2 to 10 carbon atoms, a dicarboxylic acid having a larger number of carbon atoms, for example, up to 30 carbon atoms can also be used.
Specific examples of such aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, fumaric acid, 2,2-dimethylglutaric acid, and suberic acid. , 1,3-cyclopentadicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, diglycolic acid, itaconic acid, maleic acid, and 2,5-norbornanedicarboxylic acid. Among them, adipic acid is preferred.
As the ester-forming derivative of the aliphatic dicarboxylic acid, for example, dimethyl ester, diethyl ester, di-n-propyl ester, di-isopropyl ester, di-n-butyl ester, di-isobutyl ester of the aliphatic dicarboxylic acid, Examples include di-t-butyl ester, di-n-pentyl ester, di-isopentyl ester or di-n-hexyl ester. Anhydrides of dicarboxylic acids can likewise be used.
Further, the aliphatic dicarboxylic acid or its ester-forming derivative can be used alone or as a mixture of two or more thereof.
Particular preference is given to using ester-forming derivatives such as adipic acid or its alkyl esters or mixtures thereof.
[0030]
The following are examples of the aromatic dicarboxylic acid or its ester-forming derivative which gives the repeating unit (5).
The aromatic dicarboxylic acids according to the present invention include those having generally 8 to 12 carbon atoms, especially those having 8 carbon atoms. Specific examples thereof include terephthalic acid, isophthalic acid, 2,6-naphthoic acid, 1,5-naphthoic acid and ester-forming derivatives thereof.
Examples of the ester-forming derivative of the aromatic dicarboxylic acid include di-C of the aromatic dicarboxylic acid. ₁ ~ C ₆ Alkyl esters such as dimethyl ester, diethyl ester, di-n-propyl ester, di-isopropyl ester, di-n-butyl ester, di-n-butyl ester, di-isobutyl ester, di-t-butyl ester, di- Examples thereof include n-pentyl ester, di-isopentyl ester and di-n-hexyl ester.
Particular preference is given to using terephthalic acid or its ester-forming derivatives such as dimethyl terephthalate.
Further, the aromatic dicarboxylic acid or its ester-forming derivative can be used alone or as a mixture of two or more thereof.
[0031]
Examples of the aliphatic diol or the derivative thereof that provides the repeating unit (6) include a branched or linear aliphatic diol having 2 to 12 carbon atoms, preferably 4 to 6 carbon atoms, or 5 to 10 carbon atoms. And a cyclic aliphatic diol having the following carbon atom.
[0032]
As such aliphatic diols, specifically, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2 Isobutyl-1,3-propanediol, 2,2,4-trimethyl-1,6-hexanediol, especially ethylene glycol, 1,3-propanediol, 1,4-butanediol and 2,2-dimethyl -1,3-propanediol (neopentyl glycol); cyclopentanediol, 1,4-cyclohexanediol, 1,2-cyclohexane Sandimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol and 2,2,4,4-tetramethyl-1,3-cyclobutanediols, and diethylene glycol, triethylene glycol, polyethylene glycol, and polypropylene glycol And polytetrahydrofuran, in particular diethylene glycol, triethylene glycol and polyethylene glycol or mixtures thereof or compounds having a different number of ether units. As such an aliphatic diol, a mixture of different aliphatic diols can be used.
[0033]
The aromatic polyester copolymer (b) according to the present invention is represented, for example, by a sodium salt of 5-sulfoisophthalic acid, in addition to the aliphatic dicarboxylic acid component, the aromatic dicarboxylic acid component and the aliphatic diol component. Sulfonate group-containing compounds such as alkali metal salts or alkaline earth metal salts of a dicarboxylic acid having a sulfonate group or an ester-forming derivative thereof; glycolide (1,4-dioxane-2,5-dione), D-, L- Glycolic acid represented by dilactide (3,6-dimethyl-1,4-dioxane-2,5-dione), p-hydroxybenzoic acid, D-, L-, D, L-lactic acid, 6-hydroxyhexane Acids and cyclic derivatives thereof, and their derivatives represented by, for example, 3-polyhydroxybutyric acid, polyhydroxyvaleric acid, polylactide and the like. Hydroxycarboxylic acids such as Goma and polymers; 2-aminoethanol, 3-aminopropanol, 4-aminobutanol, 5-amino pentanol, amino -C typified 6-amino hexanol ₂ ~ C ₆ Amino-C represented by alkanol, 4-aminomethylcyclohexanemethanol, aminocyclopentanol and aminocyclohexanol ₅ ~ C ₆ Amino-C such as cycloalkanol, or mixtures thereof ₂ ~ C ₁₂ -Alkanol or amino-C ₅ ~ C ₁₀ -Cycloalkanol; diamino-C represented by 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane (hexamethylenediamine "HMD") and the like ₁ ~ C ₈ Alkanes: 2,2'-bis (2-oxazoline), bis (2-oxazolinyl) methane, 1,2-bis (2-oxazolinyl) ethane, 1,3-bis (2-oxazolinyl) propane or 1,4 2 represented by -bis (2-oxazolinyl) butane, 1,4-bis (2-oxazolinyl) benzene, 1,2-bis (2-oxazolinyl) benzene, 1,3-bis (2-oxazolinyl) benzene, etc. , 2'-bisoxazoline; represented by valine, leucine, isoleucine, threonine, methionine, phenylalanine, tryptophan, lysine, alanine, arginine, aspartameic acid, cysteine, glutamic acid, glycine, histidine, proline, serine, tyrosine, asparagine, and glutamine. Natural amino acids; or sake Acid, citric acid, malic acid, trimethylolpropane, trimethylolethane, pentaerythritol, polyethertriol, glycerin, trimesic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic dianhydride and hydroxyisophthalate Compounds having at least three groups capable of forming an ester represented by an acid, such as a hydroxyl group and / or a carboxyl group; toluylene-2,4-diisocyanate, toluylene-2,6-diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthylene-1,5-diisocyanate or xylylene-diisocyanate, tri (4 An isocyanate compound such as an aromatic diisocyanate such as isocyanophenyl) methane; an aliphatic diisocyanate such as n-hexamethylene diisocyanate; and 1,4-butanediol-divinyl ether, 1,6-hexanediol-divinyl ether, A chain extender such as divinyl ether such as 4-cyclohexanedimethanol-divinyl ether may be contained as a copolymerization component.
Such an aromatic polyester copolymer (b) can be produced by various known methods. Specific polymerization methods are described in, for example, JP-T-2002-527644 and JP-T-2001-501652. As the aromatic polyester copolymer (b), for example, it is sold by BASF under the trade name ECOFLEX (registered trademark).
[0034]
Polylactic acid polymer (c)
The polylactic acid-based polymer (c) added as an optional component to the biodegradable polyester composition of the present invention has an MFR (according to ASTM D-1238; load of 2160 g, temperature of 190 ° C.) of 0.1 to 100 g / 10. Min, preferably 1 to 50 g / 10 min, particularly preferably 2 to 10 g / 10 min.
The type of the polylactic acid-based polymer (c) is a D, L-polylactic acid copolymer, and preferably has a D-form content of 5 to 50%, particularly preferably 10 to 20%. It is a polylactic acid copolymer. By using a copolymer in such a range as the polylactic acid-based polymer (c), a molded article having high toughness can be obtained.
The melting point of the polylactic acid-based polymer (c) is 160 ° C. or less, preferably an amorphous one.
By adding the polylactic acid-based polymer (c), when the aliphatic polyester copolymer (a) containing 20,000 ppm or less of the oligomer is used, it is possible to suppress the bleed out of the oligomer from the obtained film. Has side effects. Further, the polylactic acid-based polymer (c) is also used for the purpose of controlling the rate of biodegradability and adjusting physical properties.
[0035]
Biodegradable polyester composition
The biodegradable polyester composition of the present invention contains 95 to 50% by weight, preferably 89 to 55% by weight of the aliphatic polyester copolymer (a), and 5 to 50% by weight of the aromatic polyester copolymer (b). %, Preferably in the range of 11 to 45% by weight. If the amount of the aromatic polyester copolymer (b) is less than 5% by weight, the tear resistance of the obtained film may not be improved, while if it exceeds 50% by weight, the gloss of the obtained film decreases. In addition, the film may have low strength, and may be easily stretched by a small stress (external force).
When the aliphatic polyester copolymer (a) containing the oligomer at 20,000 ppm or less is used as the aliphatic polyester copolymer (a), the aromatic polyester copolymer (b) is mixed. Has the secondary effect of suppressing bleeding of oligomers from the resulting film, but if the amount of the aromatic polyester copolymer (b) is less than 5% by weight, the effect may not be exhibited.
[0036]
The biodegradable polyester composition of the present invention comprises 30 parts by weight of the polylactic acid-based polymer (c) based on 100 parts by weight of the aliphatic polyester copolymer (a) and the aromatic polyester copolymer (b). By weight, preferably 5 to 25 parts by weight, it is possible to prevent a decrease in the gloss of the film due to the addition of the aromatic polyester copolymer (b), and the aliphatic polyester copolymer When an aliphatic polyester copolymer (a) containing 20,000 ppm or less of an oligomer is used as (a), there is a secondary effect that bleed from the obtained film can be suppressed.
[0037]
Additive
Additives can be added to the biodegradable polyester composition of the present invention as needed.
Examples of the additive include various known additives such as a heat stabilizer, a lubricant, an antiblocking agent, a nucleating agent, a photolytic agent, a biodegradation accelerator, an antioxidant, an ultraviolet stabilizer, an antistatic agent, an antibacterial agent and a deodorant. , A colorant and the like may be added to the extent that the object of the present invention is not impaired. The following can be specifically exemplified as such additives.
[0038]
Specific examples of the lubricant include various known lubricants such as hydrocarbon-based, fatty acid-based, higher alcohol-based, polyhydric alcohol-based, aliphatic amide-based, metal soap-based, and ester-based lubricants, and biodegradable polyester compositions. It is preferable to add 0.01 to 1% by weight to the resin component (the same applies hereinafter) because a film with further improved slip properties can be obtained. Among them, the combined use of erucamide and polyethylene glycol makes it possible to improve the workability in a well-balanced manner immediately after film formation and during subsequent cutting, and further, during printing, laminating, and bag making.
Further, a higher fatty acid such as stearic acid and an antistatic agent to be described later, particularly a polyoxyethylene alkylamine such as stearyl diethanolamine, and a nonionic surfactant such as a higher fatty acid partial ester of a polyhydric alcohol such as glycerol monooleate are used in combination By doing so, a biodegradable polyester laminated film excellent in antistatic properties and slip properties can be obtained.
[0039]
Specific examples of the antiblocking agent include silica, talc, mica, inorganic compound particles such as zeolite and metal oxides obtained by calcining a metal alkoxide, polymethyl methacrylate, melamine formalin resin, melamine Organic compound particles such as urea resin and polyester resin can be exemplified. It is preferable to add 0.01 to 1% by weight of such a known antiblocking agent to the biodegradable polyester composition, since a film having further improved blocking resistance can be obtained. Among them, silica and polymethyl methacrylate are particularly preferred in terms of blocking resistance and transparency.
The particle diameter of such an antiblocking agent is preferably from 0.1 to 7 μm.
[0040]
Various known antistatic agents, for example, cationic surfactants represented by quaternary ammonium compounds, anionic surfactants represented by alkyl sulfonates, partial fatty acid esters of polyhydric alcohols, Nonionic surfactants typified by ethylene oxide adducts of fatty amines or fatty amides, and the like are included. Further specifically, as the partial fatty acid ester of the polyhydric alcohol, glycerin monostearate, glycerin monooleate, glycerin monolaurate, glycerin monofatty acid esters such as glycerin monopalmitate, sorbitan laurate, sorbitan palmitate, Examples of sorbitan fatty acid esters such as sorbitan stearate and sorbitan triolate, and ethylene oxide adducts of fatty amines and fatty amides include polyoxyethylene laurylamine, polyoxyethylene tallowamine, and stearyldiethanolamine. The amount of such an antistatic agent added to the biodegradable polyester composition is usually in the range of 0.01 to 1% by weight.
[0041]
The kneading method with the aliphatic polyester copolymer (a), the aromatic polyester copolymer (b), the polylactic acid-based polymer (c) added as needed, and / or the additive is performed by a general method. The method is preferably used. Specifically, raw resin pellets, powders, solid flakes, and the like are dry-mixed with a Henschel mixer or a ribbon mixer, and a single-screw or twin-screw extruder, a Banbury mixer, a kneader, a mixing roll, or the like is used. And melt-kneading it.
[0042]
The biodegradable polyester film of the present invention is obtained by forming the kneaded product obtained above by a T-die film forming method, an inflation film forming method, a calender film forming method, an extrusion laminated film forming method, or the like.
[0043]
The biodegradable polyester film of the present invention has a thickness of 5 to 500 µm, preferably 10 to 100 µm.
[0044]
When the aliphatic polyester copolymer (a) containing the oligomer at 20,000 ppm or less is used as the aliphatic polyester copolymer (a), the film obtained above is further subjected to an annealing treatment, Bleed out of the oligomer can be effectively suppressed.
The annealing temperature depends on the amount (composition ratio) of the aromatic polyester copolymer (b) or the polylactic acid-based polymer (c) added as necessary, but is usually 30 to 60 ° C, preferably. Is in the range of 35 to 50C, more preferably 35 to 45C. If the annealing temperature is lower than 30 ° C., the effect of further suppressing the bleed out of the oligomer may not be observed. If the temperature is higher than 60 ° C., the film may be too soft and may be blocked.
The annealing time depends on the temperature, but is usually 10 hours or more, preferably 24 to 480 hours, and more preferably 72 to 360 hours. If the annealing time is less than 10 hours, the effect of further suppressing bleed out of the oligomer may not be exhibited. The upper limit is not particularly limited, but if it exceeds 480 hours, the expression of the suppressing effect is saturated.
[0045]
The film of the present invention has the following features.
As optical characteristics, haze (HZ) is 30% or less, preferably 25% or less.
As an optical characteristic, the parallel light transmittance (PLT) is 60% or more, preferably 65% or more.
Gloss: 30% or more, preferably 50% or more.
Tear strength (both MD and TD): 110 mN or more, preferably 120 mN or more.
Young's modulus (both MD and TD): 200 to 1000 MPa, preferably 300 to 800 MPa.
Tensile strength (MD): 30 MPa or more, preferably 40 MPa or more.
Tensile strength (TD): 15 MPa or more, preferably 30 MPa or more.
Elongation (MD): 50% or more.
Elongation (TD): 50% or more.
Yield point stress (MD): 15 MPa or more, preferably 20 MPa or more.
Yield point stress (TD): 10 MPa or more, preferably 20 MPa or more.
[0046]
The film of the present invention includes a sheet, a film, and a tape. The film may be used as a single layer, but may be a laminate with another substrate. When obtaining a laminated film, the film obtained from the biodegradable polyester composition of the present invention and another substrate may be formed into a co-extruded film using a multilayer die. The composition may be extruded and laminated on a substrate obtained in advance to form a laminated film, or a separately obtained film or the like may be laminated to form a laminated film. Examples of the substrate include films, sheets, cups and trays obtained from polylactic acid, aliphatic polyester and aromatic polyester, or foams thereof, glass, metal, aluminum foil, paper and the like. When the substrate is a film made of a thermoplastic resin, it may be unstretched or a uniaxially or biaxially stretched film. Of course, the base material may be one layer or two or more layers.
The film of the present invention is excellent in transparency, and is formed by secondary molding, and is used for fusing and sealing packages for delivering home and postal items, precision parts, protective films for personal computers, home electric appliances, car seats, etc., for food, especially vegetables. And dry food, confectionery, especially snack confectionery, clothing, pharmaceuticals, cassettes, video tapes, and various other packaging, and degradable garbage bags, drainage bags, perforated films, agricultural multi (weed-proof) films, vegetation films, and stickers It can be processed into films, root-wrap sheets, drainage sheets, curing sheets, buffer sheets, buffer materials, cards and the like.
[0047]
The film of the present invention is useful as a general packaging film as described above because it is excellent in heat sealability and fusing seal strength, but among others, as a fusing seal packaging film accompanied by fusing seal, especially for magazines and the like It can be suitably used as a fusing seal packaging film for heavy objects.
The film of the present invention can be used in the form of a packaging bag. At this time, by attaching a chuck (fastener, zipper) made of the aromatic polyester copolymer (b) to the mouth of the packaging bag, the packaging bag can be easily opened and closed.
[0048]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.
[0049]
Film raw material
(A) Aliphatic polyester copolymer
PCBS-11: succinic acid-1,4-butanediol-ε-caprolactone terpolymer, caprolactone content 4 mol%, Mw 220,000 (standard polystyrene equivalent molecular weight in GPC measurement), manufactured by Daicel Chemical Industries, Ltd. , MFR (190 ° C, load 2160g) 0.9g / 10min, Tm 104 ° C, density 1.24g / cm ³ , Oligomer content 6900 weight ppm.
(B) Aromatic polyester copolymer
PBA / T: manufactured by BASF, trade name ECOFLEX (registered trademark), adipic acid-terephthalic acid-1,4-butanediol (46 mol% of terephthalic acid, 54 mol% of adipic acid), MFR (190 ° C., load 2160 g) 3g / 10min, Tm112 ° C, density 1.26g / cm ³ .
(C) Polylactic acid-based polymer
PLAC: manufactured by Mitsui Chemicals, Inc., polylactic acid copolymer, D-lactic acid content 11%, MFR (190 ° C., load 2160 g) 2.6 g / 10 min, amorphous, Tg 55 ° C.
[0050]
Resin additive
Erucamide (EA): Ciba Specialty Chemicals, trade name ATMER SA1753
Silica (SI): manufactured by Fuji Silysia Chemical Ltd., trade name: Sylysia 730 (particle size: 4 μm)
The above was added to the resin composition in an amount of 1000 ppm by weight based on the resin content.
[0051]
Various measurement methods in the present invention are as follows.
(1) Oligomer content (ppm): In the GPC measurement of the above polymer, the content was determined by the area ratio to the whole of those having a molecular weight of 500 or less in terms of standard polystyrene in a chloroform solvent.
(2) Sensory evaluation of bleed-out: The surface of the non-stretched film was rubbed with a fingertip and evaluated based on the degree of adhesion to the finger.な い indicates little adhesion, Δ indicates slight adhesion, and X indicates adhesion that is clearly unusable for normal use.
(3) Haze (HZ): The cloudiness of a non-stretched film was measured using NDH-300A manufactured by Nippon Denshoku Industries. The measured value is an average of five measurements.
(4) Parallel light transmittance (PLT): The parallel light transmittance of the unstretched film was measured using NDH-300A manufactured by Nippon Denshoku Industries. The measured value is an average of five measurements.
(5) Tensile properties: As a test piece, a strip-shaped film piece (length: 150 mm, width: 15 mm) in the MD or TD direction is sampled from a non-stretched film, a tensile test is performed at a distance between chucks of 100 mm, and the yield point The strength (stress) (MPa), elongation (%) and Young's modulus (MPa) at the breaking point were determined. The elongation (%) was a change in the distance between the chucks.
The measurement conditions are as follows.
Equipment used: Orientec Tensilon Universal Testing Machine RTC-1225
Crosshead speed: 300 mm / min (however, the Young's modulus was measured at 5 mm / min.)
The measured value is an average of five measurements.
(6) Fusing seal strength
Using a non-stretched film, an A4 large notebook was automatically filled at a rate of 5000 sets / hour by a fusing type continuous bag making machine and evaluated. The fusing seals of the upper and lower portions (flow direction is upward) were obtained by heating the fusing blade at an angle of 90 ° to 310 ° C, and sealing the back-attached portion by heating a half-moon type iron to 300 ° C.
A 15 mm wide sample was cut out from the upper, lower, and back portions of the obtained packaging bag, and the strength of the fusing seal was pulled at a pulling speed of 300 mm / min using a Tensilon Universal Testing Machine RTC-1225 manufactured by Orientec. The maximum strength was defined as the fusing seal strength.
(7) Heat seal strength
A urethane-based adhesive (trade name Takerac A968 (20%) + takerac A8 (20%) + Using ethyl acetate (60%)), an unstretched film was dry-laminated to obtain a laminated film having a thickness of 57 to 58 μm.
The unstretched film surfaces of the obtained laminated films are superimposed, and a seal surface pressure of 1 kg / cm is applied at a predetermined temperature using TP-701-B HEATSEALTESTER manufactured by Tester Sangyo Co., Ltd. ² Heat sealing (heat sealing) was performed for 1 second. The heating was performed only on the upper side. Next, the heat-sealed laminated film was peeled at a tensile speed of 300 mm / min from a heat-sealed sample having a width of 15 mm using a Tensilon Universal Tester RTC-1225 manufactured by Orientec Co., Ltd. did.
[0052]
[Examples 1 to 4, Comparative Examples 1 and 2]
The aliphatic polyester copolymer (a) and the aromatic polyester copolymer (b) were previously melt-kneaded at the ratios shown in Table 1 to obtain a biodegradable polyester composition.
Using the biodegradable polyester composition obtained above, an unstretched film having a thickness of 30 μm was obtained using a T-die film forming machine.
Table 1 shows the evaluation results of the film.
[0053]
[Table 1]

[0054]
As is clear from Table 1, the tear strength of the unstretched film is significantly improved by increasing the amount of the aromatic polyester copolymer (b) in the biodegradable polyester composition (Examples). 1-4, Comparative Example 1).
The unstretched film obtained from the aliphatic polyester copolymer (a) causes bleed-out of the oligomer (Comparative Example 1), whereas the addition of the aromatic polyester copolymer (b) causes It can be seen that bleed-out is suppressed (Examples 1 to 4).
[0055]
[Examples 5 to 9, and Reference Examples 1 to 3]
The aliphatic polyester copolymer (a), the aromatic polyester copolymer (b) and the lactic acid polymer (c) are previously melt-kneaded in the proportions shown in Table 2 to obtain a biodegradable polyester composition. Was.
Using the biodegradable polyester composition obtained above, an unstretched film having a thickness of 30 μm was obtained using a T-die film forming machine. Table 2 shows the evaluation results of the film.
[0056]
[Table 2]

[0057]
As is clear from Table 2, a biodegradable polyester composition comprising an aliphatic polyester copolymer (a) and an aromatic polyester copolymer (b) was added with a lactic acid-based polymer (c). It can be seen that the unstretched film obtained from the polyester composition has excellent gloss (comparison between Example 6 and Example 2, and Example 5 and Example 7).
In the unstretched film obtained from the aliphatic polyester copolymer (a), bleed out of the oligomer occurs (Comparative Example 1), whereas the aromatic polyester copolymer (b) and the lactic acid polymer (c) ) Indicates that the bleed out of the oligomer is suppressed (Examples 5 to 8).
[0058]
[Examples 10 and 11]
To the non-stretched film obtained in Example 7, a biaxially stretched polylactic acid film having a thickness of 25 μm was coated with a urethane-based adhesive (Takelac A968 (20%) (trade name, manufactured by Takeda Pharmaceutical Co., Ltd.) + A8 (20%) + acetic acid). Ethyl (60%)) to form a laminated film. The laminated film was cut into a predetermined size, the laminated film piece was folded in two in the width direction, and the lower and side portions were melt-sealed to obtain a packaging bag having an opening at the upper portion.
Separately, using the PBA / T resin, a band having a convex portion and a band having a concave portion which are engaged with each other to be a chuck were prepared.
On the unstretched film surface side of the upper portion of the laminated film piece, the band having the convex portion and the band having the concave portion were heat-sealed, respectively, to obtain a laminated film piece with a chuck. The package was folded, and the lower and side portions were melt-sealed to obtain a packaging bag having an opening with a chuck at the upper portion. The zipper of the packaging bag was repeatedly opened and closed, but the zipper portion was flexible and did not peel off from the laminated film.
[0059]
【The invention's effect】
According to the present invention, a biodegradable polyester film having excellent transparency, particularly excellent in fusing seal strength, heat sealing strength, and tear strength, is suitable for use as a flexible and suitable film for automatic filling packaging such as fusing seal packaging. A polyester film is obtained.

Claims (15)

The molecular chain is a repeating unit represented by the following general formulas (1) to (3):
—CO—R ¹ —CO— (1)
(In the formula, R ¹ represents a divalent aliphatic group having 1 to 12 carbon atoms.)
—OR ² —O— (2)
(In the formula, R ² represents a divalent aliphatic group having 2 to 12 carbon atoms.)
A repeating unit represented by the following general formula (3):
—CO—R ³ —O— (3)
(In the formula, R ³ represents a divalent aliphatic group having 1 to 10 carbon atoms.)
And a repeating unit (3) of 1 to 25 mol% (in the general formulas (1) to (3), the amounts of the repeating units (1) and (2) are substantially equal, and the repeating units (1) and (2) And the total amount of (3) is 100 mol%), and 95 to 50% by weight of an aliphatic polyester copolymer (a) having a weight average molecular weight of 40,000 or more, and
The molecular chain is a repeating unit represented by the following general formulas (4) to (6):
—CO—R ⁴ —CO— (4)
(In the formula, R ⁴ represents a divalent aliphatic group having 0 to 8 carbon atoms.)
—CO—R ⁵ —CO— (5)
(In the formula, R ⁵ represents a divalent aromatic group having 8 to 12 carbon atoms.)
-OR ⁶ -O- (6)
(In the formula, R ⁶ represents a divalent aliphatic group having 2 to 12 carbon atoms.)
20 to 95 mol% of the repeating unit (4) and 80 to 5 mol% of the repeating unit (5) (the total of the repeating units (4) and (5) is 100 mol%, and the repeating units (4) and (4) 5) and 5 to 50% by weight of the aromatic polyester copolymer (b) (where the total of (a) and (b) is 100% by weight). %).) A biodegradable polyester composition comprising: 100 parts by weight of a low-molecular-weight aliphatic polyester copolymer (a ') having a weight-average molecular weight of 5,000 or more, which is a polymerization intermediate of the aliphatic polyester copolymer (a), 2. The biodegradable polyester composition according to claim 1, which is obtained by reacting 0.1 to 5 parts by weight of a diisocyanate compound with respect to the high molecular weight. The polylactic acid-based polymer (c) is added in an amount of 30 parts by weight or less based on 100 parts by weight of the composition of the aliphatic polyester copolymer (a) and the aromatic polyester copolymer (b). Or the biodegradable polyester composition according to 2. The biodegradable polyester composition according to any one of claims 1 to 3, wherein the general formula (1) is a succinic acid residue and / or an adipic acid residue. The biodegradable polyester composition according to any one of claims 1 to 4, wherein the general formula (2) is an ethylene glycol residue and / or a 1,4-butanediol residue. The biaxially stretched laminated film according to any one of claims 1 to 5, wherein the general formula (3) is a ring-opened group of ε-caprolactone. The biodegradable polyester composition according to any one of claims 1 to 6, wherein the general formula (4) is an adipic acid residue or a succinic acid residue. The biodegradable polyester composition according to any one of claims 1 to 7, wherein the general formula (5) is a terephthalic acid residue. The biodegradable polyester composition according to any one of claims 1 to 8, wherein the general formula (6) is an ethylene glycol residue and / or a 1,4-butanediol residue. The biodegradable polyester composition according to any one of claims 1 to 9, wherein the polylactic acid-based polymer (c) is a polylactic acid copolymer containing 5 to 50% of a D-form. A biodegradable polyester film obtained from the biodegradable polyester composition according to claim 1. A packaging film comprising the biodegradable polyester film according to claim 11. A packaging bag comprising the packaging film according to claim 12. 14. The packaging bag according to claim 13, wherein the packaging bag is a fusing seal packaging bag. 15. The packaging bag according to claim 13, wherein a chuck made of the aromatic polyester copolymer (b) according to claim 1 is joined to a mouth of the packaging bag.