JP3886613B2 - Molded body and manufacturing method thereof - Google Patents

Description

（一般式（１）において、Ｒ¹ 、Ｒ² は炭素原子数１〜３０の飽和、不飽和炭化水素で、直鎖状、分岐状の炭化水素基であり、ｎは、１〜４の整数である。）
［２］ ポリ乳酸系樹脂が、
ポリ乳酸、ポリ乳酸ブロックとポリブチレンサクシネートブロックを有する共重合体、ポリ乳酸ブロックとポリカプロン酸ブロックを有する共重合体からなる群から選択された少なくとも一種である［１］に記載したポリ乳酸系樹脂成形体。
【００１６】
[ ３ ] 一般式（１）［化１］で表される化合物群から選択された少なくとも一種の透明化剤（Ｂ）が、ジイソデシルアジペートである [ １ ] 又は [ ２ ] に記載したポリ乳酸系樹脂成形体。
[ ４ ] ポリ乳酸系樹脂（Ａ）と、一般式（１）［化２］で表される化合物群から選択された少なくとも一種の透明化剤（Ｂ）を含有するポリ乳酸系樹脂成形体の製造方法であって、前記ポリ乳酸系樹脂（Ａ）と前記透明化剤（Ｂ）の合計重量を基準として、前記ポリ乳酸系樹脂（Ａ）を９４〜９９重量％、及び、前記透明化剤（Ｂ）を６〜１重量％含有するポリ乳酸系樹脂組成物を成形するに際し、成形時又は成形後に熱処理することを特徴とする、ｌｍｍ厚のヘイズ値が３０％以下であることと等価である透明性及びビカット軟化点が１００〜１６０℃であることに相当する耐熱性を併有することを特徴とするポリ乳酸系樹脂成形体の製造方法。
【００１７】
【化４】

（一般式（１）において、Ｒ ¹ 、Ｒ ² は炭素原子数１〜３０の飽和、不飽和炭化水素で、直鎖状、分岐状の炭化水素基であり、ｎは、１〜４の整数である。）
【００１８】
[ ５ ] 熱処理方法が、ポリ乳酸系樹脂組成物を一旦溶融した後、ポリ乳酸系樹脂組成物の結晶化開始温度から結晶化終了温度迄の温度範囲に保温された金型内に充填し結晶化させることを特徴とする、 [ ４ ] に記載した製造方法。
[ ６ ] 熱処理方法が、ポリ乳酸系樹脂組成物の溶融物を、金型内で冷却固化して非晶性成形体を得た後、その成形体をポリ乳酸系樹脂（Ａ）のガラス転移温度から融点迄の温度範囲で結晶化することを特徴とする、 [ ４ ] に記載した製造方法。
[ ７ ] 熱処理方法が、ポリ乳酸系樹脂組成物の非晶性成形体を得た後、その成形体をポリ乳酸系樹脂（Ａ）のガラス転移温度から融点迄の温度範囲で結晶化することを特徴とする、 [ ４ ] に記載した製造方法。
【００１９】
[ ８ ] ポリ乳酸系樹脂が、ポリ乳酸、ポリ乳酸ブロックとポリブチレンサクシネートブロックを有する共重合体、ポリ乳酸ブロックとポリカプロン酸ブロックを有する共重合体からなる群から選択された少なくとも一種である、 [ ６ ] 乃至 [ ７ ] の何れかに記載した製造方法。
[ ９ ] 一般式（１）［化２］で表される化合物群から選択された少なくとも一種の透明化剤（Ｂ）が、ジイソデシルアジペートである [ ４ ] 乃至 [ ８ ] の何れかに記載した製造方法。
【００２０】
［１０］ [ ４ ] 乃至 [ ９ ] の何れかに記載した製造方法により得られた、ｌｍｍ厚のヘイズ値が３０％以下であることと等価である透明性及びビカット軟化点が、１００〜１６０℃であることに相当する耐熱性を併有するポリ乳酸系樹脂成形体。
【００２１】
【発明の実施の形態】
以下、本発明について詳細に説明する。
［ポリ乳酸系樹脂］
本発明において、ポリ乳酸系樹脂とは、ポリ乳酸、乳酸とヒドロキシカルボン酸のコポリマー（例えば、乳酸とグリコール酸のコポリマー、乳酸とカプロン酸のコポリマー、ポリ乳酸とポリカプロン酸のブロックコポリマー等）、乳酸及び脂肪族多価アルコールと脂肪族多価カルボン酸のコポリマー（例えば、乳酸とブタンジオールとコハク酸及びアジピン酸のコポリマー、乳酸とエチレングリコール及びブタンジオールとコハク酸のコポリマー、ポリ乳酸とポリブチレンサクシネートのブロックコポリマー等）、及びそれらの混合物を包含する。又、混合物の場合、相溶化剤を含有してもよい。ポリ乳酸系樹脂がコポリマーの場合、コポリマーの配列の様式は、ランダム共重合体、交替共重合体、ブロック共重合体、グラフト共重合体等のいずれの様式でもよい。さらに、これらは少なくとも一部が、キシリレンジイソシアネート、２，４−トリレンジイソシアネート等のような多価イソシアネートやセルロース、アセチルセルロースやエチルセルロース等のような多糖類等の架橋剤で架橋されたものでもよく、少なくとも一部が、線状、環状、分岐状、星形、三次元網目構造、等のいずれの構造をとってもよく、何ら制限はない。
【００２２】
本発明のポリ乳酸系樹脂において、ポリ乳酸、特にポリ−Ｌ−乳酸、ポリカプロン酸、特にポリ−ε−カプロン酸、ポリ乳酸とポリ−６−ヒドロキシカプロン酸のブロックコポリマー、特にポリ−Ｌ−乳酸とポリ−６−ヒドロキシカプ口ン酸のブロックコポリマー、ポリ乳酸とポリブチレンサクシネートのブロックコポリマー、特にポリ−Ｌ−乳酸とポリブチレンサクシネートのブロックコポリマーが好ましい。
【００２３】
［脂肪族ヒドロキシカルボン酸］
本発明においてポリ乳酸系樹脂を構成する脂肪族ヒドロキシカルボン酸の具体例としては、例えば、グリコール酸、乳酸、３−ヒドロキシ酩酸、４−ヒドロキシ酩酸、４−ヒドロキシ吉草酸、５−ヒドロキシ吉草酪、６−ヒドロキシカプロン酸等が挙げられる。これらは一種類又は二種類以上の混合物であってもよい。また脂肪族ヒドロキシカルボン酸が不斉炭素を有する場合、Ｌ体、Ｄ体、及びその混合物、すなわち、ラセミ体であってもよい。
【００２４】
［脂肪族多価カルボン酸及びその無水物］
本発明においてポリ乳酸系樹脂を構成する脂肪族多価カルボン酸の具体例としては、例えば、シュウ酸、コハク酸、マロン酸、グルタル酸、アジピン酸、ピメリン酸、スベリン酸、アゼライン酸、セバシン酸、ウンデカン二酸、ドデカン二酸等の脂肪族ジカルボン酸等及びその無水物等が挙げられる。これらは一種類又は二種類以上の混合物であってもよい。
【００２５】
［脂肪族多価アルコール］
本発明においてポリ乳酸系樹脂を構成する脂肪族多価アルコールの具体例としては、例えば、エチレングリコール、ジエチレングリコール、トリエチレングリコール、プロピレングリコール、ジプロピレングリコール、１，３−ブタンジオール、ｌ，４−ブタンジオール、３−メチル−１，５−ペンタンジオール、１，６−ヘキサンジオール、１，９−ノナンジオール、ネオペンチルグリコール、テトラメチレングリコール、１，４−シクロヘキサンジメタノール等が挙げられる。これらは一種類又は二種類以上の混合物であってもよい。
【００２６】
［多糖類］
多糖類の具体例としては、例えば、セルロース、硝酸セルロース、酢酸セルロース、メチルセルロース、エチルセルロース、セルロイド、ビスコースレーヨン、再生セルロース、セロハン、キュプラ、銅アンモニアレーヨン、キュプロファン、ベンベルグ、ヘミセルロース、デンプン、アミロペクチン、デキストリン、デキストラン、グリコーゲン、ペクチン、キチン、キトサン、アラビアガム、グァーガム、ローカストビーンガム、アカシアガム、等、及びこれらの誘導体が挙げられるが、特にアセチルセルロース、エチルセルロースが好的に用いられる。
これらは、一種類又は二種類以上の混合物であってもよい。
【００２７】
［ポリ乳酸系樹脂の分子量］
本発明において使用するポリ乳酸系樹脂の分子量は、目的とする用途、例えば包装材及び容器などの成形体にした場合に、実質的に充分な機械物性を示すものであれば、その分子量は、特に制限されない。
ポリ乳酸系樹脂の分子量としては、一般的には、重量平均分子量として、１〜５００万が好ましく、３〜３００万がより好ましく、５〜２００万がより好ましく、７〜１００万がさらに好ましく、９〜５０万が最も好ましい。
一般的には、重量平均分子量がｌ万より小さい場合、機械物性が充分でなかったり、逆に、分子量が５００万より大きい場合、取扱いが困難となったり不経済となったりする場合がある。
本発明において使用するポリ乳酸系樹脂の重量平均分子量及び分子量分布は、その製造方法において、溶媒の種類、触媒の種類及び量、反応温度、反応時間
、共沸により留出した溶媒の処埋方法、反応系の溶媒の脱水の程度等の反応条件を適宜選択することにより所望のものに制御することができる。
【００２８】
［ポリ乳酸系樹脂の製造方法］
本発明のポリ乳酸系樹脂の製造方法は、特に制限されない。
例えば、ポリ乳酸及び構造単位に乳酸を有するポリ乳酸系樹脂の製造方法の具体例としては、特開平６−６５３６０号に開示されている方法を参考した、後述の製造例２に示すような方法が挙げられる。
すなわち、乳酸及び／又は乳酸以外のヒドロキシカルボン酸を、あるいは脂肪族ジオールと脂肪族ジカルボン酸を、有機溶媒及び触媒の存在下、そのまま脱水縮合する直接脱水縮合法である。
構造単位に乳酸を有するポリ乳酸系樹脂の製造方法の他の参考例としては、例えば、特開平７−１７３２６６号に開示されている方法を参考した、後述の製造例３〜６に示すような方法が挙げられる。
すなわち、少なくとも２種類のポリ乳酸系樹脂のホモポリマーを重合触媒の存在下、共重合並びにエステル交換反応させる方法である。
ポリ乳酸の製造方法の他の具体例としては、例えば、米国特許第２，７０３，３１６号に開示されている方法を参考にした、後述の製造例１に示すような方法が挙げられる。
すなわち、乳酸及び／又は乳酸以外のヒドロキシカルボン酸を、一旦、脱水し環状二量体とした後に、開環重合する間接重合法である。
【００２９】
［透明化剤］
本発明において使用される透明化剤は、一般式（１）［化５］で示される脂肪酸エステル類である。
【００３０】
【化５】

（一般式（１）において、Ｒ¹ 、Ｒ² は炭素原子数１〜３０の飽和、不飽和炭化水素で、直鎖状、分岐状の炭化水素基であり、ｎは、１〜４の整数である。）
本発明方法における脂肪酸エステル類の具体例としては、ジメチルアジペート、ジ−２−エチルヘキシルアジペート、ジイソブチルアジペート、ジブチルアジペート、ジイソデシルアジペート、ジブチルジグリコールアジペート、ジ−２−エチルヘキシルアジペート、ジブチルセバケート、ジ−２−エチルヘキシルセバケート等があげられる。特に、ジイソデシルアジペートが好ましい。
【００３１】
［透明化剤の添加量］
透明化剤のポリ乳酸系樹脂への添加量は、ポリ乳酸系樹脂組成物に対して１〜６重量％になるように添加でき、好ましくは、１．５〜５．５重量％、さらに好ましくは２．０〜５．０重量％である。
１重量％より小さいと、透明化剤としての効果が不十分となる場合があり、逆に６重量％より大きくなると、透明化剤としての効果は得られなくなるばかりか、結晶化した際に透明性が悪くなったりする等、外観や物性（剛性）に変化を来す場合がある。
【００３２】
［無機添加剤］
本発明の製造方法により製造する成形体には、成形体の透明性を損なわない限り、結晶化速度の向上、耐熱性の向上、機械物性の向上、耐ブロッキング性の向上等の諸物性を改善するために無機添加剤を添加することもできる。
無機添加剤の具体例としては、例えば、タルク、カオリナイト、ＳｉＯ₂、クレー等が挙げられるが、成形体の透明性を損なわないように適宜、条件（添加量、粒子サイズ）を選択する必要がある。成形体の透明性を保持する為には、一般的に可視光の波長よりも実質的に小さな粒子サイズを選択することが推奨される。
【００３３】
より具体的には、耐ブロッキング性の物性改良を目的とした場合、例えば、粒径が１〜５０ｎｍのＳｉＯ₂等が透明性を損なうことなく好適に用いられる。
本発明の製造方法において、成形時の金型内での結晶化や生成した成形体の熱処理による結晶化などの成形加工時の結晶化速度をさらに向上させることを目的とした場合、ＳｉＯ₂成分を１０重量％以上含む結晶性の無機物が好ましく、具体的には、タルクＴＭ−３０（富士タルク社製）、カオリンＪＰ−１００（土屋カオリン社製）、ＮＮカオリンクレー（土屋カオリン社製）、カオリナイトＡＳＰ−１７０（富士タルク社製）、カオリンＵＷ（エンゲルハード社製）、タルクＲＦ（富士タルク社製）等が挙げられる。この場合、粒径が小さく、樹脂と溶融混練した場合に凝集することなく良好に分散するものが好適に用いられる。
【００３４】
［無機添加剤の添加量］
無機添加剤の添加量は、成形体の透明性を極端に損なわない程度の量が好ましく、ポリ乳酸系樹脂組成物１００重量部に対して、３０重量％以下、好ましくは２０重量％以下、より好ましくは１０重量％以下、さらに好ましくは５重量％以下、最も好ましくはｌ重量％以下が好適である。
【００３５】
本発明の製造方法により製造する成形体には、さらに、成形体の透明性を損なわない限り、各種エラストマー（ＳＢＲ、ＮＢＲ、ＳＢＳ型３元ブロック共重合体熱可塑性エラストマー等）や添加剤（可塑剤、顔料、安定剤、帯電防止剤、紫外線吸収剤、酸化防止剤、難燃剤、離型剤、滑剤、染料、抗菌剤）、フィラー（耐衝撃性コア／シェル型粒子、インパクトモディフアイアー等）、顔料（メタリック顔料、パール顔料）を目的や用途に応じて適宜使用することができる。
【００３６】
［成形加工法］
<混合・混練・捏和>
本発明において、ポリ乳酸系樹脂と一般式（１）［化５］で示される化合物群から選択された少なくとも一種の透明化剤を、混合・混練・捏和してポリ乳酸系樹脂組成物を製造する方法は、公知公用の混練技術、例えば、ヘンシェルミキサー、リボンブレンダー等で各原料を混合させたり、又、さらに押出機等を用いて溶融したポリマーに液注入させながら混練させる方法を採用することができる。
【００３７】
< 成形 >
以下に、本発明の目的とする透明性と結晶性を併有する成形体を製造する方法について説明する。
本発明は、前述したポリ乳酸系樹脂樹脂組成物を成形時、又は成形後に結晶化させることで、透明性と結晶性を併有する成形体を製造する方法である。
成形方法としては、一般に射出成形、押出成形、ブロー成形、インフレーション成形、異形押出成形、射出ブロー成形、真空圧空成形、紡糸等の通常の方法が挙げられるが、本発明で示す樹脂組成物においては、いずれの成形方法にも適応でき、何ら制限はない。
本発明では、ポリ乳酸系樹脂組成物を、成形時、又は成形後において、成形体を何らかの方法（例えば、熱処理）で結晶化させる必要がある。その具体例としては、例えば、成形時に該組成物の溶融物を金型内に充填し、金型内でそのまま結晶化させる方法（以下、金型内結晶化法という）、及び該組成物の非晶性の成形体を熱処理する方法（以下、後結晶化法という）を挙げることができる。この金型内結晶化法及び後結晶化法では、成形体を結晶化する際の最適の温度条件は異なる。
【００３８】
▲１▼ 金型内結晶化法における結晶化の温度条件
金型内結晶化法の場合、金型の設定温度条件は、該組成物の示差走査熱量分析における降温時の結晶化開始温度から、結晶化終了温度までの温度範囲が好ましく、結晶化ピークの頂点付近の温度がより好ましい。結晶化開始温度より高い温度では、結晶化速度が著しく小さくなり、生産性、操作性が悪くなったり、さらには結晶化しなくなり、目的とする成形体が得られない場合があり、逆に結晶化終了温度より低い温度では結晶化速度が著しく小さく、目的とする成形体が得られない場合がある。この方法では、金型内の保持時間は、該組成物によっても異なるが、金型内で、成形体が十分に結晶化するにたる時間以上であれば、特に制限はない。
【００３９】
▲２▼ 後結晶化法における結晶化の温度条件
一方、後結晶化法の場合、金型の設定温度条件は、該組成物のガラス転移温度（Ｔｇ）から融点（Ｔｍ）までの温度範囲、より好ましくは（Ｔｇ＋５℃）から（Ｔｍ−２０℃）、さらに好ましくは（Ｔｇ＋ｌ０℃）から（Ｔｍ−３０℃）最も好ましくは（Ｔｇ＋１５℃）から（Ｔｍ−４０℃）までの温度範囲がよい。設定温度がＴｍより高い場合は、短時間で結晶化させても透明性を損ねたり、形状が歪んだりする場合があり、さらに長時間加熱すると融解する場合がある。逆にＴｇより低い温度では、結晶化速度が著しく小さく、目的とする結晶性の成形体が得られない場合がある。この方法では成形体を熱処理する時間は、組成物により異なるが、成形体が十分に結晶化するに足る時間以上であれば、特に制限されない。
【００４０】
< 透明性と結晶性を併有する成形体を製造する方法の態様 >
以下に、本発明に係る、成形体に透明性と結晶性を同時に付与することができる成形体の成形方法の態様を説明する。
【００４１】
▲１▼ 射出成形 （金型内結晶化法）
射出成形（金型内結晶化法）においては、例えば、後述する製造例２で得られたポリ乳酸に透明化剤を添加し組成物のペレットの溶融物を、結晶化開始温度から結晶化終了温度の温度範囲内に保持された金型内に充填し保持することにより、本発明で目的とする透明性と結晶性を併有する成形体を成形することができる。
【００４２】
▲２▼ 射出成形 （後結晶化法）
射出成形（後結晶化法）においては、例えば、上記▲１▼に示したペレットを用いて金型温度２０℃で成形して得られた非晶性な成形体を、Ｔｇ（５８℃）からＴｍ（１６５℃）の温度範囲内の雰囲気下に保持したり、又は適当な熱媒体と接触させることにより、本発明で目的とする透明性と結晶性を併有する射出成形体を成形することができる。
【００４３】
▲３▼ 押出成形 （後結晶化法）
押出成形（後結晶化法）においては、例えば、上記▲１▼に示したペレットを、一般的なＴダイ押出成形機で成形した非晶性のフィルムやシートを、Ｔｇ（５８℃）からＴｍ（１６５℃）の範囲内に保持されたオーブン（加熱炉）中や温水中に連続的に通過させ熱処理したり、あるいはバッチ的に熱処理したりすることにより、本発明で目的とする透明性と結晶性を併有するシートやフィルムを成形することができる。
【００４４】
▲４▼ ブロー成形（後結晶化法）
ブロー成形（後結晶化法）においては、上記▲１▼に示したペレットを、一般的なブロー成形機で溶融して金型に充填することにより非晶性な予備成形体を得た後、得られた予備成形体をオーブン（加熱炉）中で加熱した後に、Ｔｇ（５８℃）からＴｍ（１６５℃）の範囲内に保持された金型内に入れて、圧力空気を送出してブローすることにより、本発明で目的とする透明性と結晶性を併有するブローボトルを成形することができる。
ここで、圧力空気として、高温［例えば、室温（２５℃）以上からＴｍ（１６５℃以下の温度］のものを用いると、成形体の結晶化に要する時間を短縮することができる。
【００４５】
▲５▼ 真空成形・真空圧空成形（金型内結晶化法）
上記▲３▼と同様な方法により成形した非晶性なフィルムを、一般的な真空成形機により、結晶化開始温度から結晶化終了温度の範囲内に保持された金型内で真空成形又は真空圧空成形することにより、本発明で目的とする透明性と結晶性を併有する成形体を成形することができる。
ここで、圧力空気として、高温［例えば、室温（２５℃）以上からＴｍ（１６５℃以下の温度］のものを用いると、成形体の結晶化に要する時間を短縮することができる。
【００４６】
▲６▼ 真空成形・真空圧空成形（結晶性フィルムの真空成形）
上記▲３▼と同様な方法により成形した結晶性のフィルムを、真空圧空成形することにより、本発明で目的とする透明性と結晶性を併有する成形体を成形することができる。
以上のような成形方法により成形して得られた本発明のポリ乳酸系樹脂成形体は、結晶性と透明性を併有し、高い耐熱性を有する。
【００４７】
本発明において、ポリ乳酸系樹脂成形体が透明性を有するということは、厚みがｌｍｍの該成形体と新聞を重ねた場合に、該成形体を介して新聞の文字を認識できる程度の透明性を有することを意味し、厚みがｌｍｍの該成形体のヘイズが３０％以下であることを意味する。
本発明において、ポリ乳酸系樹脂成形体が耐熱性であるということは、Ｘ線回折法により測定された結晶化度が１０％以上であることを意味する。
つまり、耐熱性であるということは、ビカット軟化点（ビカット軟化温度）測定（ＡＳＴＭ Ｄ１５２５）において、ビカット軟化点（ビカット軟化温度）が、１００〜１６０℃であることを意味する。
本発明の製造方法により、結晶化度が１０％以上であり、厚みがｌｍｍにおいてヘイズが３０％以下の結晶性（耐熱性）と透明性を併有するポリ乳酸系樹脂成形体が得られる。
本発明の製造方法により、結晶化度が３０％以上であっても、厚みがｌｍｍにおいてヘイズが３０％以下、２０％以下、１５％以下、さらには１０％以下の結晶性（耐熱性）と透明性を併有するポリ乳酸系樹脂成形体が得られる。
【００４８】
本発明の透明性、結晶性（耐熱性）及び分解性を有するポリ乳酸系樹脂成形体は、公知、公用の成形法で得られる射出成形品、フィルム、袋、チューブ、シート、カップ、ボトル、トレー、糸等を包含し、その形状、大きさ、厚み、意匠等に関して何ら制限はない。
具体的には、本発明の成形体は、食品包装用袋、食器やフォーク、スプーン、乳製品や清涼飲料水及び酒類等用のボトル、ラップフィルム等の食品用の容器、トレイ、ボトル及びフィルム、化粧品容器、ゴミ袋、かさ、（粘着）テープ、エアーマット、漂白剤用の容器、液体洗剤類用のボトル等の日用雑貨品、テント、防水シート等のレジャー用品、医療器具、医療材料、医薬品等の容器や包装材品、つり糸、魚網、農業用品の容器や包装材及びカプセル、肥料用の容器や包装材及びカプセル、種苗用の容器や包装材及びカプセル、農園芸用フィルム、製品包装用フィルム、オーバーヘッドプロジェク夕一用フィルム、熱線反射フィルム、液晶ディスプレー用フィルム等に用いることができる。
【００４９】
この他、本発明の方法で得られるフィルムやシートは、紙や他のポリマー等の他の材質のシートと、接着剤や熱融着によるラミネートや貼り合わせ等により、多層構造の積層体とすることもできる。
特に、従来、ポリ乳酸やポリ乳酸ブロックとポリブチレンサクシネートブロックを有する共重合体のような透明性に優れているポリ乳酸系樹脂の非晶性のフィルムを、例えば、紙等に熱ラミネーションした場合、ラミネーション時の熱により、結晶化し、不透明になるという問題があった。
したがって、透明性が要求される用途の場合、熱ラミネーション時の熱処理条件を限定したり、接着剤を用いるラミネーション方法が好ましく用いられ、さらには、透明性と耐熱性を要求される用途の場合は、該樹脂組成物を用いることはできなかった。
しかしながら、本発明の透明化剤を含むそれらの樹脂組成物を用いた場合、例えば、透明な非晶性フィルムをそのまま紙等に熱ラミネーシヨンし、紙等への貼り合わせと該組成物の結晶化を同時に行ってもよい。
また、一旦熱ラミネーションした積層体をさらに熱処理して結晶化させてもよい。いずれの条件下でも、その透明性を維持し、さらには、耐熱性を付与した積層体を得ることができる。
【００５０】
【実施例】
以下に製造例、実施例及び比較例等を示し、本発明を詳述する。
なお、本出願の明細書における合成例、実施例、比較例、態様等の記載は、本発明の内容の理解を支援するための説明であって、その記載は本発明の技術的範囲を狭く解釈する根拠となる性格のものではない。
【００５１】
Ａ．製造例
実施例及び比較例において使用するポリ乳酸系樹脂の製造方法を以下に示す。なお、文中に部とあるのはいずれも重量基準である。
また、重合体の平均分子量（重量平均分子量Ｍｗ）はポリスチレンを標準としてゲルパーミエーションクロマトグラフィーにより以下の条件で測定した。
▲１▼ 装置 ：島津ＬＣ−ＩＯＡＤ
▲２▼ 検出器：島津ＲＩＤ−６Ａ
▲３▼ カラム：日立化成ＧＬ−Ｓ３５０ＤＴ−５、ＧＬ−Ｓ３７０ＤＴ−５
▲４▼ 溶 媒：クロロホルム
▲５▼ 濃 度：ｌ％
▲６▼ 注入量：２０μ1
［製造例１］ < ポリマーＡ（ポリＬ−ラクタイド）の製造>
Ｌ−ラタタイド１００重量部及びオクタン酸第一錫０．０１部と、ラウリルアルコール０．０３部を、攪拌機を備えた肉厚の円筒型ステンレス製重合容器へ封入し、真空で２時間脱気した後窒素ガスで置換した。この混合物を窒素雰囲気下で攪拌しつつ２００℃で３時間加熱した。温度をそのまま保ちながら、排気管及びガラス製受器を介して真空ポンプにより徐々に脱気し反応容器内を３ｍｍＨｇまで減圧にした。脱気開始からｌ時間後、モノマーや低分子量揮発分の留出がなくなったので、容器内を窒素置換し、容器下部からポリマーをストランド状に抜き出してペレット化し、Ｌ−ラクタイドのホモポリマー（ポリマーＡ）を得た。収率は７８％、重量平均分子量Ｍｗは、１３．６万であった。
【００５２】
［製造例２］ < ポリマーＢ（ポリＬ−乳酸）の製造>
Ｄｉｅｎ−Ｓｔａｒｋトラップを設置した１００リットルの反応器に、９０％Ｌ−乳酸１０ｋｇを１５０℃／５０ｍｍＨｇで３時間攪拌しながら水を留出させた後、錫末６．２ｇを加え、１５０℃／３０ｍｍＨｇでさらに２時間攪拌してオリゴマー化した。このオリゴマーに錫末２８．８ｇとジフェニルエーテル２１．１ｋｇを加え、１５０℃／３５ｍｍＨｇ共沸脱水反応を行い、留出した水と溶媒を水分離器で分離して溶媒のみを反応器に戻した。２時間後、反応器に戻す有機溶媒を４６ｋｇのモレキュラシーブ３Ａを充填したカラムに通してから反応器に戻るようにして、１５０℃／３５ｍｍＨｇで４０時間反応を行い、重量平均分子量１４．６万のポリ乳酸の溶液を得た。この溶液に脱水したジフェニルエーテル４４ｋｇを加え、希釈した後４０℃まで冷却して、析出した結晶を瀘過し、ｌ０ｋｇのｎ−ヘキサンで３回洗浄して６０℃／５０ｍｍＨｇで乾燥した。この粉末を０．５Ｎ−ＨＣｌ１２ｋｇとエタノールｌ２ｋｇを加え、３５℃でｌ時間攪拌した後瀘過し、６０℃／５０ｍｍＨｇで乾燥して、白色粉末のポリ乳酸６．ｌｋｇ（収率８５％）を得た。このポリ乳酸（ポリマーＢ）の重量平均分子量Ｍｗは、１４．５万であった。
【００５３】
［製造例３］< コポリマーＣ（ポリブチレンサクシネート／ポリ乳酸共重合体）の製造>
１，４−ブタンジオール５０．５ｇとコハク酸６６．５ｇにジフェニルエーテル２９３．０ｇ）金属錫２．０２ｇを加え、１３０℃／１４０ｍｍＨｇで７時間系外に水を留出しながら加熱攪拌しオリゴマー化した。これに、Ｄｅａｎ−Ｓｔａｒｋ ｔｒａｐを取り付け、１４０℃／３０ｍｍＨｇで８時間共沸脱水を行いその後、モレキュラーシーブ３Ａを４０ｇ充填した管を取り付け、留出した溶媒がモレキュラーシーブ管中を通って反応器に戻るようにし、１３０℃／１７ｍｍＨｇで４９時間攪拌した。その反応マスを６００ｍｌのクロロホルムに溶かし、４リットルのアセトンに加え再沈した後、ＨＣｌのイソプロピルアルコール（以下ＩＰＡと略す）溶液（ＨＣｌ濃度０．７ｗｔ％）で０．５時間スラッジングし（３回）、ＩＰＡで洗浄してから減圧下６０℃で６時間乾燥し、ポリブチレンサクシネート（以下ＰＳＢと略す）を得た。このポリマーの重量平均分子量Ｍｗは、１１．８万であった。
得られたポリブチレンサクシネート８０．０ｇに、製造例２と同様な方法で得られたポリ乳酸１２０．０ｇ（重量平均分子量Ｍｗは２．０万）、ジフェニルエーテル８００ｇ）金属錫０．７ｇを混合し、再び１３０℃／１７ｍｍＨｇで２０時間脱水縮合反応を行った。反応終了後、製造例２と同様に後処理を行い、ポリブチレンサクシネートとポリ乳酸とのコポリマー１８８ｇ（収率９４％）を得た。このポリブチレンサクシネートとポリ乳酸とのコポリマー（コポリマーＣ）の重量平均分子量Ｍｗは１４．０万であった。
【００５４】
［製造例４］ < コポリマーＤ（ポリブチレンサクシネート／ポリ乳酸共重合体）の製造>
ポリブチレンサクシネート４０．０ｇ（重量平均分子量Ｍｗは１１．８万）、ポリ乳酸１６０．０ｇ（重量平均分子量Ｍｗは５．０万）を用いた他は、製造例３と同様な方法で行った結果、ポリブチレンサクシネートとポリ乳酸とのコポリマー（コポリマーＤ）を得た。収率は９６％、重量平均分子量Ｍｗは１３．６万であった。
【００５５】
［製造例５］＜コポリマーＥ（ポリブチレンサクシネート／ポリ乳酸共重合体）の製造>
ポリブチレンサクシネート２０．０ｇ（重量平均分子量Ｍｗは１１．８万）、ポリ乳酸１８０．０ｇ（重量平均分子量Ｍｗは１０．０万）を用いた他は、製造例３と同様な方法で行った結果、ポリブチレンサクシネートとポリ乳酸とのコポリマー（コポリマーＥ）を得た。収率は９４％、重量平均分子量Ｍｗは１４．２万であった。
【００５６】
［製造例６］＜コポリマーＦ（ポリカプロン酸／ポリ乳酸共重合体）の製造>
乳酸のかわりに、６−ヒドロキシカプロン酸を用いた他は製造例２と同様な方法で反応を行った結果、ポリカプロン酸（重量平均分子量Ｍｗは１５．０万）を得た。次に得られたポリカプロン酸２０．０ｇとポリ乳酸１８０．０ｇ（重量平均分子量Ｍｗは１０．０万）を用い製造例４と同様な方法で行い、ポリカプロン酸とポリ乳酸とのコポリマ（コポリマーＦ）を得た。収率は９２％、重量平均分子量Ｍｗは１５．３万であった。
【００５７】
Ｂ．評価方法
［物性の評価］
製造例１〜６で得たポリ乳酸系樹脂組成物を用いて製造した成形体の物性の評価条件は、以下のとおりである。
▲１▼ 透明性 （ヘイズ）
ＪＩＳ Ｋ−６７１４に従い、東京電色製Ｈａｚｅ Ｍｅｔｅｒを使用して測定した。
【００５８】
▲２▼ 結晶化度
Ｘ線回折装置（理学電機製、Ｒｉｎｔ１５００型）にて成形後の試験片を測定し、得られたチャートの結晶ピーク面積の総面積に対する比率を求めた。
▲３▼ 耐熱性 ［ビカット軟化温度（ＡＳＴＭ−Ｄ１５２５）］
荷重１ｋｇｆの条件で成形後の試験片を測定。
【００５９】
▲４▼ 結晶化開始温度、結晶化終了温度
示差走査熱量分析装置（島津製作所製、ＤＳＣ−５０）にて成形体を一旦溶融した後、１０℃／ｍｉｎの条件下で降温した時の結晶化ピークが認められた温度を結晶化開始温度、結晶化ピークが認められなくなった温度を結晶化終了温度とした。
【００６０】
▲５▼ ガラス転移温度（Ｔｇ）、融点（Ｔｍ）
示差走査熱量分析装置（島津製作所製、ＤＳＣ−５０）にて成形体を１０℃／ｍｉｎの条件下で昇温した時のゴム状に変わる点をガラス転移点（Ｔｇ）、融解ピークの頂点を融点（Ｔｍ）とした。
【００６１】
Ｃ．実施例及び比較例
以下の実施例において、成形体を熱処理している場合、金型内結晶化操作で降温時に結晶化している場合は、降温時の結晶化開始温度以下から結晶化終了温度以上である範囲内に設定し、又成形後熱処理操作で昇温時に結晶化している場合は、ガラス転移温度以上から融点以下である温度範囲内に設定した。
【００６２】
［実施例１〔射出成形〕］
製造例２で得られたポリ乳酸９５重量部、透明化剤としてジイソデシルアジペート５重量部をヘンシェルミキサーで充分に混合した後、押出機シリンダー設定温度１７０〜２１０℃の条件にてペレット化した。該ペレットを日本製鋼所製ＪＳＷ−７５射出成形機、シリンダー設定温度１８０〜２００℃の条件にて溶融し、設定温度３０℃の金型に充填し、冷却時間は３０秒としてｌ．０ｍｍ厚の透明な平滑な平板成形体を得た。この平板の透明性（ヘイズ）は２％、結晶化度は０％、ビカット軟化点は５８℃であった。
この平板を乾燥機中で１２０℃／５ｍｉｎで熱処理した。得られた平板の透明性（ヘイズ）は６％、結晶化度４０％、ビカット軟化点は１５０℃であった。結果を表−１［表１］に示す。
【００６３】
［実施例１−２〜１−６〔射出成形〕］
ポリマー、透明化剤の添加量を表−１［表１］に示すように変更した以外は、実施例１−１と同様にして行い、それぞれ得られた平板の透明性（ヘイズ）、結晶化度、ビカット軟化点を測定した。結果を表−１［表１］に示す。
【００６４】
［比較例１−１〜１−６〔射出成形〕］
透明化剤のジイソデシルアジペートを除いた他は、実施例１と同様な方法で行った。それぞれ得られた平板の透明性（ヘイズ）、結晶化度、ビカット軟化点を測定した。結果を表−２［表２］に示す。
【００６５】
［実施例２−１〔ブロー成形〕］
ポリマーとして製造例２で得られたポリ乳酸、透明化剤としてジイソデシルアジペート５重量％をヘンシェルミキサーで充分に混合した後、押出機シリンダー設定温度１７０〜２１０℃の条件にてペレット化した。該ペレットを射出ブロー成形機（日精ＡＳＢ機械製、ＡＳＢ−５０）、シリンダー設定温度１８０〜２００℃の条件にて溶融し、設定温度２０℃の金型（Ａ）に充填、冷却時間は３０秒、２．０ｍｍ肉厚の予備成形体（有底パリソン）を得た。得られたパリソンを加熱炉中にてパリソン温度を１２０℃に加熱し、さらに温度を１２０℃に保持した金型(B) に入れ、圧力空気の圧力４ｋｇｆ／ｃｍ²の条件下で、たて倍率
２倍、よこ倍率２倍にし、内容積５００ｍｌの容器を得た。得られた容器（厚み０．５ｍｍ）の透明性（ヘイズ）は３％（ｌｍｍ厚のヘイズに換算すると７％）、結晶化度は４３％、ビカット軟化点は１５０℃であった。
【００６６】
［比較例２−１〔ブロー成形〕］
透明化剤（ジイソデシルアジペート）を除いた以外は、実施例４と同様な方法で行った。得られた容器（厚み０．５ｍｍ）の透明性（ヘイズ）は７５％（ｌｍｍ厚のヘイズに換算すると８０％）、結晶化度は４５％、ビカット軟化点は１５０℃であった。
【００６７】
［比較例２−２〔ブロー成形〕］
パリソン温度を５５℃、金型（Ｂ）温度を３０℃にした以外は、実施例４−１と同様な方法で行った。得られた容器（厚み０．５ｍｍ）の透明性（ヘイズ）は１．３％（ｌｍｍ厚のヘイズ値に換算すると３％）、結晶化度は０％、ビカット軟化点は５９℃であった。
【００６８】
［実施例３−１〔押出成形〕］
ポリマーとして製造例１で携られたポリ乳酸、透明化剤としてジイソデシルアジペート５重量％をヘンシェルミキサーで充分に混合した後、押出機シリンダー設定温度１７０〜２１０℃の条件にてペレット化した。該ペレットをＴダイ５０ｍｍΦ押出機（フロンティア製、ダイ幅４００ｍｍ）シリンダー設定温度１８０〜２００℃の条件にて溶融し、ダイ温度１８５℃にて透明な０．５ｍｍ厚のシートを得た。このシート（厚み０．５ｍｍ）の透明性（ヘイズ）は１％（ｌｍｍ厚のヘイズ値に換算すると２％）、結晶化度は０％であった。
さらに、このシートを熱風乾燥機（温度１００℃、滞留時間２ｍｉｎ）に連続して通過させて熱処埋した。得られたシートの透明性は３％（ｌｍｍ厚のヘイズに換算すると８％）、結晶化度は４０％であった。
【００６９】
［比較例３−１〔押出成形〕］
透明化剤のジイソデシルアジペートを除いた他は実施例５−１と同様な方法で行った。得られたシートの透明性（ヘイズ）は７３％（ｌｍｍ厚のヘイズに換算すると８４％）、結晶化度は３９％であった。
【００７０】
［比較例３−２〔押出成形〕］
実施例３−１で得られたシート（厚み０．５ｍｍ）ヘイズ値は１％、結晶化度は０％）を熱風乾燥機中で温度５５℃で２０ｍｉｎ間熱処理した。得られたシート（厚み０．５ｍｍ）の透明性（ヘイズ）は１％（ｌｍｍ厚のヘイズに換算すると２％）、結晶化度は０％であった。
【００７１】
［実施例４−１〔インフレーション成形〕］
製造例４で得られた重合体（ポリブチレンサクシネートとポリ乳酸とのコポリマー）を用い、透明化剤としてジイソデシルアジペート５重量部を、ヘンシェルミキサーで充分に混合した後、押出機シリンダー設定温度１７０〜２１０℃の条件にてペレット化した。
該べレットをインフレーション成形機（川田製作所製、４５ｍｍΦ）シリンダー設定温度１６５〜１８０℃の条件にて溶融し、ダイ温度１７０℃、膨張比（ＢＵＲ）２．５にて折径２５０ｍｍ）厚み０．０５ｍｍ、のインフレーションフィルムを得た。このフィルムの透明性（ヘイズ）は０．５％（ｌｍｍ厚のヘイズに換算すると３％）、結晶化度は０％であった。
さらに、得られたフィルムを温水中（温度８５℃、滞留時間２ｍｉｎ）で熱処埋した。このフィルム（厚み０．０５ｍｍ）の透明性（ヘイズ）は０．７％（ｌｍｍ厚のヘイズに換算すると５％）、結晶化度は３５％であった。
【００７２】
［比較例４−１〔インフレーション成形〕］
透明化剤（ジイソデシルアジペート）を除いた以外は、実施例４−１と同方法で行った。得られたシート（厚み０．５ｍｍ）の透明性（ヘイズ）は４３％（ｌｍｍ厚のヘイズに換算すると７０％）、結晶化度は３４％であった。
【００７３】
［実施例５−１〔異型押出成形〕］
ポリマーとして製造例２で得られたポリ乳酸、透明化剤としてジイソデシルアジペート５重量％をヘンシェルミキサーで充分に混合した後、押出機シリンダー設定温度１７０〜２１０℃の条件にてぺレット化した。該ペレットを異型ダイ４０ｍｍΦ押出機（フロンティア製、ダイ形状は四角の中空）シリンダー設定温度１８０〜２００℃の条件にて溶融し、ダイ温度１７５℃にて押出し、真空装置付サイジングボックス（冷却温度３０℃）内で成形し、肉厚０．５ｍｍ、外寸法４０ｍｍ×３０ｍｍの中空成形体を得た。この中空体の透明性（ヘイズ）は１．５％（ｌｍｍ厚のヘイズに換算すると２％）、結晶化度は０％であった。
さらに、中空体を熱風乾燥機（温度１００℃）滞留時間２ｍｉｎ）に連続して通過させて熱処理し、中空体を得た。得られた中空体（厚み０．５ｍｍ）の透明性（ヘイズ）は３．５％（ｌｍｍ厚のヘイズに換算すると８％）、結晶化度は４１％であった。
【００７４】
［比較例５−１〔異型押出成形〕］
透明化剤（ジイソデシルアジペート）を除いた他は実施例８と同様な方法行った。得られたシート（厚み０．５ｍｍ）の透明性（ヘイズ）は７１％（ｌｍｍ厚のヘイズに換算すると７７％）、結晶化度は４０％であった。
【００７５】
［実施例６−１〔真空・圧空成形−１；結晶化させたシートの成形〕］
ポリマーとして製造例２で得られたポリ乳酸、透明化剤としてジイソデシルアジペート５重量％をヘンシェルミキサーでよく混合した後、押出機シリンダー設定温度１７０〜２１０℃の条件にてペレット化した。該べレットをＴダイ５０ｍｍΦ押出機（フロンティア製、ダイ幅４００ｍｍ）シリンダー設定温度１８０〜２００℃の条件にて溶融し、ダイ温度１８５℃にて厚み０．２５ｍｍのシー卜を得た。
このシート（厚み０．２５ｍｍ）の透明性（ヘイズ）は１．０％（ｌｍｍ厚のヘイズに換算すると２％）、結晶化度は０％であった。さらに、このシートを熱風乾燥機（温度１００℃）滞留時間２ｍｉｎ）に連続して通過させて熱処理した。得られたシート（厚み０．２５ｍｍ）の透明性（ヘイズ）は２．５％（ｌｍｍ厚のヘイズに換算すると７％）、結晶化度は３８％であった。
【００７６】
次いで、このシートを長径１４６ｍｍ、短径１００ｍｍ、深さ３０ｍｍの楕円形金型を備えた真空圧空成形機を使用し、加熱温度１２０℃、保持時間３０秒で軟化させ、金型温度６０℃に設定した上記楕円形金型に圧空圧力４ｋｇｆ／ｃｍ²で、１０秒間真空密着（減圧度５０ｍｍＨｇ）させて成形体を得た。成形体の透明性（ヘイズ）は３％（ｌｍｍ厚のヘイズに換算すると８％）、結晶化度は４０％であった。
【００７７】
［実施例６−２〔真空・圧空成形−２；非結晶シートを型内で結晶化〕］
実施例６−１で得られた厚み０．２５ｍｍのシート（ヘイズ値は０％、結晶化度は０％）を用い、長径１４６ｍｍ、短径１００ｍｍ、深さ３０ｍｍの楕円形金型を備えた真空圧空成形機を使用し、加熱温度８５℃）保持時間４０秒で軟化さ せ、金型温度を１００℃に設定した上記楕円形金型に圧空圧力１ｋｇｆ／ｃｍ²で、１分間真空密着（減圧度５０ｍｍＨｇ）させて成形体を得た。
成形体の透明性（ヘイズ）は３％（ｌｍｍ厚のヘイズに換算すると８％）、結晶化度は４１％であった。
【００７８】
［比較例６−１］
透明化剤（ジイソデシルアジペート）を除いた以外は、実施例６−２と同様な方法で行った。得られた成形体の透明性（ヘイズ）は７３％（ｌｍｍ厚のヘイズに換算すると８２％）、結晶化度は４２％であった。
【００７９】
［比較例６−２］
金型温度を５５℃にした以外は、実施例６−２と同様な方法で行った。得られた成形体（厚み０．２５ｍｍ）の透明性（ヘイズ）はｌ％（ｌｍｍ厚のヘイズに換算すると２％）、結晶化度は０％であった。
【００８０】
【表１】

【００８１】
【表２】

【００８２】
【発明の効果】
本発明により、透明性と結晶性（耐熱性）とを同時に有する、ポリ乳酸系樹脂成形体を提供することができる。[0001]
BACKGROUND OF THE INVENTION
  The present invention is a polylactic acid-based resin molded article containing a polylactic acid-based resin (A) and a clarifying agent (B) having a specific chemical structure, the polylactic acid-based resin (A) and the transparency Containing 94 to 99% by weight of the polylactic acid resin (A) and 6 to 1% by weight of the clarifying agent (B) based on the total weight of the agent (B), and, Having both transparency equivalent to a haze value of 1 mm thickness being 30% or less and heat resistance corresponding to a Vicat softening point of 100 to 160 ° C.The present invention relates to a polylactic acid-based resin molded product and a method for producing the same.
[0002]
[Prior art]
Recently, when general-purpose plastics are disposed of after use, they increase the amount of garbage and are hardly decomposed in the natural environment, so even if they are buried, they remain in the ground semi-permanently and are discarded. As a result, the landscape is damaged and the living environment of marine life is destroyed.
In contrast, as thermoplastic and degradable polymers, polyhydroxycarboxylic acids such as polylactic acid, aliphatic polyhydric alcohols such as polybutylene succinate, and aliphatic polycarboxylic acids derived from aliphatic polycarboxylic acids Polyester has been developed.
Some of these polymers degrade 100% within a few months to 1 year in the animal's body, and when placed in soil or seawater, they begin to degrade in a few weeks in a moist environment. It has disappeared in a few years, and the decomposition product has the property of becoming lactic acid, carbon dioxide and water that are harmless to the human body, and is attracting attention as an alternative to medical materials and general-purpose resins. .
[0003]
On the other hand, recently, electronics, mechatronics, optoelectronics, laser (optical communication, CD-ROM, CD-R, LDNDVD) magneto-optical recording and the like are also included. ), The demand for transparent plastic films has increased with the rapid development of technology development in the fields of liquid crystal, optics, office automation (OA), factory automation, etc., and its applications are also expanding dramatically.
Specific examples of the application include uses such as a film for an overhead projector, a film for plate making, a tracing film, a food wrapping film, and an agricultural film.
Specific examples of high-performance applications include, for example, transparent conductive films (for example, computer input screen touch panels), heat ray reflective films, liquid crystal display films, liquid crystal display polarizing films, PCBs (printed circuit boards), and the like. Can be mentioned.
[0004]
Conventionally, hard films with low flexibility such as glass, acrylic (polymethylmethacrylate, PMMA), polycarbonate (PC), etc. have been used for these applications. However, there is a tendency to require replacement with a transparent film excellent in flexibility, ease of molding, heat resistance, and the like. Some of these alternative demands can be met with polyethylene terephthalate (PET) films.
However, for example, in applications where degradability is required, PET may be a problem.
From such a background, it is expected that a transparent film having both transparency / heat resistance (crystallinity) / decomposability is significant in the technical field of transparent films. By the way, a molded article of an aliphatic polyester such as polylactic acid which is a degradable, thermoplastic polymer, lactic acid and other aliphatic hydroxycarboxylic acid and / or a copolymer of aliphatic polyhydric alcohol and aliphatic polycarboxylic acid (for example, A molded article such as a ball having a three-dimensional shape, an unstretched film or sheet having a two-dimensional shape, an unstretched filament or yarn having a three-dimensional shape) is usually amorphous immediately after molding. It is transparent because there are almost no crystals having a size equal to or larger than the wavelength of light that causes light scattering.
However, since this transparent molded body is usually amorphous, it is poor in heat resistance.
[0005]
For example, an amorphous polylactic acid container is excellent in transparency but has low heat resistance, so that hot water or a microwave oven cannot be used, and its application is limited.
For this reason, in order to improve the heat resistance, the mold is held in the vicinity of the crystallization temperature during the molding process, or a heat treatment (annealing) of the amorphous molded product after the molding is performed, When the crystallinity is increased, a crystal (for example, a spherulite) having a size equal to or larger than the wavelength of light that causes light scattering usually grows rapidly, and the crystal is larger than the wavelength of visible light. It grows so much that the molded body becomes opaque.
[0006]
Thus, according to the prior art, polylactic acid-based resin moldings such as polylactic acid and lactic acid and other aliphatic hydroxycarboxylic acids and / or copolymers of aliphatic polyhydric alcohols and aliphatic polycarboxylic acids. In addition, it is difficult to impart transparency and crystallinity at the same time, as if in contradiction, and there is no polylactic acid resin molded body having both transparency and crystallinity (heat resistance). It was a fact.
[0007]
On the other hand, in the technical field related to general-purpose resins, a technique is known in which a transparent nucleating agent (clearing crystal nucleating agent) is added to control the growth of spherulites and to simultaneously impart transparency to a molded body. The clarifying agent is said to have an action of suppressing excessive growth in “size”, an action of increasing in “number”, and an action of promoting in “crystallization rate” for crystals.
Specific examples thereof include, for example, terephthalic acid and resorcinol in order to increase the crystallization rate of polyethylene terephthalate by adding a sorbitol derivative to polypropylene resin to impart transparency to the molded polypropylene resin. The method etc. which add the aromatic polyester fine powder made into a structural unit can be mentioned.
However, in the technical field related to aliphatic polyester, the transparent nucleating agent suppresses excessive growth in the “size”, increases in the “number”, and accelerates in the “crystallization rate” by the transparent nucleating agent. A technique for simultaneously imparting transparency and crystallinity to a molded body is not known.
[0008]
[Action mechanism of transparent nucleating agent]
The mechanism of the transparency expression by the transparent nucleating agent in the crystalline resin molding is not necessarily clear. Further, the present invention is not limited to a specific mechanism or hypothesis. When a transparent nucleating agent is added to make the crystalline resin molded body transparent, it is usually necessary to appropriately set crystal growth conditions (for example, crystallization temperature, crystallization time, etc.). The mechanism of the transparency expression by the transparent nucleating agent in the crystalline resin molded body can be explained by the following model, for example.
[0009]
(1) Crystalline resin molding model without transparent nucleating agent
When the resin molding is crystallized without adding the transparent nucleating agent, there are relatively few crystal nuclei as a foothold for crystal growth compared to the ingot gold added with the transparent nucleating agent. Spherulites are generated, and as a result, the size of each spherulite becomes relatively overwhelming. In other words, a relatively small number of large crystals are produced per unit volume even when the crystallinity is the same, compared to the case where a transparent nucleating agent is added. Since the crystal is formed, the visible light is not scattered and travels straight, so that the crystalline resin molded body to which the transparent nucleating agent is not added becomes opaque.
[0010]
(2) Crystalline resin molding model with transparent nucleating agent added
When the transparent nucleating agent is added to crystallize the resin molded body, the transparent nucleating agent becomes a crystal nucleus that increases the amount of crystal growth. As a result, an overwhelmingly large number of crystals are formed, and as a result, the size of each crystal can be relatively overwhelmingly small.
In other words, compared to the case where the transparent nucleating agent is not added per unit volume, a relatively large number of small crystals are generated even if the crystallinity is the same, and as a result, it is much smaller than the wavelength of visible light. Since crystals of the shape are generated, the crystalline resin molded body to which the transparent nucleating agent is added can be made transparent because the crystal proceeds straight without scattering visible light.
[0011]
[Transparent nucleating agent for aliphatic polyester]
The inventors of the present invention have conceived that it is a very meaningful solution to simultaneously exhibit transparency and crystallinity in a molded body of polylactic acid resin. Until now, the present inventors have not recognized the location of such a problem by those skilled in the art.
From these viewpoints, the present inventors have actually made polylactic acid-based resins such as polylactic acid, lactic acid and other aliphatic hydroxycarboxylic acids and / or copolymers of aliphatic polyhydric alcohols and aliphatic polycarboxylic acids. In addition, sorbitol derivatives that are transparent nucleating agents for polypropylene resins, phosphorus nucleating agents, talc, silica, calcium lactate or sodium benzoate were used as transparent nucleating agents. These polylactic acid resin moldings could not be imparted with transparency and crystallinity at the same time.
Thus, for polylactic acid resins such as polylactic acid and lactic acid and other aliphatic hydroxycarboxylic acids and / or copolymers of aliphatic polyhydric alcohols and aliphatic polycarboxylic acids, general injection molding and blow molding are used. In a molding technique such as compression molding, it is difficult to simultaneously exhibit transparency and crystallinity (heat resistance) even when a publicly known transparent nucleating agent is used during molding or before and after molding.
[0012]
[Problems to be solved by the invention]
An object of the present invention is to obtain a polylactic acid-based resin molded article including polylactic acid having both transparency and crystallinity (heat resistance) at the same time.
[0013]
[Means for Solving the Problems]
  As a result of intensive investigations to achieve the above object, the present inventors have added a compound having a specific chemical structure to a polylactic acid resin, and crystallized the molded body at the time of molding or after molding, thereby achieving transparency. It was found that a molded product having both crystallinity and heat resistance was obtained, and the present invention was completed. The present invention provides the following [1] to[10]It is specified by the matters described in.
[0014]
[1] A polylactic acid resin molded product containing a polylactic acid resin (A) and at least one clearing agent (B) selected from the group of compounds represented by the general formula (1) [Chemical Formula 1] The polylactic acid resin (A) is 94 to 99% by weight based on the total weight of the polylactic acid resin (A) and the clarifying agent (B), and the clearing agent (B). 6 to 1% by weight, and, Having both transparency equivalent to a haze value of 1 mm thickness being 30% or less and heat resistance corresponding to a Vicat softening point of 100 to 160 ° C.A featured polylactic acid resin molded product.
[0015]
[Chemical Formula 3]

(In the general formula (1), R¹, R²Is a saturated or unsaturated hydrocarbon having 1 to 30 carbon atoms, and is a linear or branched hydrocarbon group, and n is an integer of 1 to 4. )
[2] Polylactic acid resin
The polylactic acid described in [1], which is at least one selected from the group consisting of polylactic acid, a copolymer having a polylactic acid block and a polybutylene succinate block, and a copolymer having a polylactic acid block and a polycaproic acid block Resin molded body.
[0016]
[ 3 ] At least one clarifying agent (B) selected from the compound group represented by the general formula (1) [Chemical Formula 1] is diisodecyl adipate. [ 1 ] Or [ 2 ] The polylactic acid resin molded product described in 1.
[ 4 ] In the manufacturing method of the polylactic acid-type resin molding containing the polylactic acid-type resin (A) and at least 1 type of clearing agent (B) selected from the compound group represented by General formula (1) [Chemical Formula 2]. The polylactic acid resin (A) is 94 to 99% by weight based on the total weight of the polylactic acid resin (A) and the clarifying agent (B), and the clearing agent (B). Transparency equivalent to a 1 mm thickness haze value of 30% or less, characterized in that when a polylactic acid resin composition containing 6 to 1% by weight is molded, heat treatment is performed during molding or after molding And the manufacturing method of the polylactic acid-type resin molding characterized by having heat resistance equivalent to that a Vicat softening point is 100-160 degreeC.
[0017]
[Formula 4]

(In the general formula (1), R ¹ , R ² Is a saturated or unsaturated hydrocarbon having 1 to 30 carbon atoms, and is a linear or branched hydrocarbon group, and n is an integer of 1 to 4. )
[0018]
[ 5 ] The heat treatment method is to melt the polylactic acid resin composition once, and then fill and crystallize the mold in a temperature range from the crystallization start temperature to the crystallization end temperature of the polylactic acid resin composition. Characterized by the [ 4 ] The manufacturing method described in 1.
[ 6 ] The heat treatment method is to cool and solidify the melt of the polylactic acid resin composition in a mold to obtain an amorphous molded body, and then the molded body is melted from the glass transition temperature of the polylactic acid resin (A). Characterized by crystallization in the temperature range up to [ 4 ] The manufacturing method described in 1.
[ 7 ] The heat treatment method is characterized in that after obtaining an amorphous molded body of a polylactic acid-based resin composition, the molded body is crystallized in a temperature range from the glass transition temperature to the melting point of the polylactic acid-based resin (A). To [ 4 ] The manufacturing method described in 1.
[0019]
[ 8 ] The polylactic acid-based resin is at least one selected from the group consisting of polylactic acid, a copolymer having a polylactic acid block and a polybutylene succinate block, and a copolymer having a polylactic acid block and a polycaproic acid block. [ 6 ] Thru [ 7 ] The manufacturing method described in any one of.
[ 9 ] At least one clarifying agent (B) selected from the compound group represented by the general formula (1) [Chemical Formula 2] is diisodecyl adipate. [ 4 ] Thru [ 8 ] The manufacturing method described in any one of.
[0020]
[10] [ 4 ] Thru [ 9 ] Obtained by the production method described in any of the above, the transparency equivalent to the haze value of 1 mm thickness being 30% or less and the heat resistance corresponding to the Vicat softening point being 100 to 160 ° C. A polylactic acid-based resin molded article having both.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[Polylactic acid resin]
In the present invention, the polylactic acid-based resin means polylactic acid, a copolymer of lactic acid and hydroxycarboxylic acid (for example, a copolymer of lactic acid and glycolic acid, a copolymer of lactic acid and caproic acid, a block copolymer of polylactic acid and polycaproic acid, etc.), lactic acid And copolymers of aliphatic polyhydric alcohols and aliphatic polycarboxylic acids (eg, copolymers of lactic acid and butanediol and succinic acid and adipic acid, copolymers of lactic acid and ethylene glycol and butanediol and succinic acid, polylactic acid and polybutylene succin Nate block copolymers, etc.), and mixtures thereof. Moreover, in the case of a mixture, you may contain a compatibilizing agent. When the polylactic acid resin is a copolymer, the copolymer may be arranged in any manner such as a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer. Furthermore, these may be at least partially crosslinked with a polyvalent isocyanate such as xylylene diisocyanate or 2,4-tolylene diisocyanate or a crosslinking agent such as cellulose, polysaccharides such as acetyl cellulose or ethyl cellulose. At least a part may take any structure such as a linear shape, a circular shape, a branched shape, a star shape, or a three-dimensional network structure, and there is no limitation.
[0022]
In the polylactic acid-based resin of the present invention, polylactic acid, particularly poly-L-lactic acid, polycaproic acid, particularly poly-ε-caproic acid, block copolymer of polylactic acid and poly-6-hydroxycaproic acid, particularly poly-L-lactic acid And block copolymers of poly-6-hydroxycapuccinic acid, block copolymers of polylactic acid and polybutylene succinate, especially block copolymers of poly-L-lactic acid and polybutylene succinate.
[0023]
[Aliphatic hydroxycarboxylic acid]
Specific examples of the aliphatic hydroxycarboxylic acid constituting the polylactic acid-based resin in the present invention include, for example, glycolic acid, lactic acid, 3-hydroxysuccinic acid, 4-hydroxysuccinic acid, 4-hydroxyvaleric acid, and 5-hydroxyvaleric acid. Examples include grass dairy and 6-hydroxycaproic acid. These may be one kind or a mixture of two or more kinds. When the aliphatic hydroxycarboxylic acid has an asymmetric carbon, it may be L-form, D-form, and a mixture thereof, that is, a racemate.
[0024]
[Aliphatic polycarboxylic acid and its anhydride]
Specific examples of the aliphatic polyvalent carboxylic acid constituting the polylactic acid resin in the present invention include, for example, oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. And aliphatic dicarboxylic acids such as undecanedioic acid and dodecanedioic acid, and anhydrides thereof. These may be one kind or a mixture of two or more kinds.
[0025]
[Aliphatic polyhydric alcohol]
Specific examples of the aliphatic polyhydric alcohol constituting the polylactic acid resin in the present invention include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, l, 4- Examples include butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, tetramethylene glycol, 1,4-cyclohexanedimethanol and the like. These may be one kind or a mixture of two or more kinds.
[0026]
[Polysaccharides]
Specific examples of polysaccharides include, for example, cellulose, cellulose nitrate, cellulose acetate, methyl cellulose, ethyl cellulose, celluloid, viscose rayon, regenerated cellulose, cellophane, cupra, copper ammonia rayon, cuprophane, bemberg, hemicellulose, starch, amylopectin, Examples thereof include dextrin, dextran, glycogen, pectin, chitin, chitosan, gum arabic, guar gum, locust bean gum, acacia gum, and the like, and acetylcellulose and ethylcellulose are particularly preferably used.
These may be one kind or a mixture of two or more kinds.
[0027]
[Molecular weight of polylactic acid resin]
If the molecular weight of the polylactic acid-based resin used in the present invention shows substantially sufficient mechanical properties when formed into a molded product such as a target application, for example, a packaging material and a container, the molecular weight is There is no particular limitation.
The molecular weight of the polylactic acid-based resin is generally preferably 1 to 5 million, more preferably 3 to 3 million, more preferably 5 to 2 million, still more preferably 7 to 1 million, as the weight average molecular weight. 90 to 500,000 is the most preferable.
Generally, when the weight average molecular weight is less than 10,000, the mechanical properties are not sufficient, and conversely, when the molecular weight is more than 5,000,000, handling may be difficult or uneconomical.
The weight average molecular weight and molecular weight distribution of the polylactic acid-based resin used in the present invention are as follows: in the production method, the type of solvent, the type and amount of catalyst, the reaction temperature, the reaction time
The desired conditions can be controlled by appropriately selecting reaction conditions such as a method for treating the solvent distilled by azeotropic distillation and the degree of dehydration of the solvent in the reaction system.
[0028]
[Production method of polylactic acid resin]
The method for producing the polylactic acid resin of the present invention is not particularly limited.
For example, as a specific example of a method for producing polylactic acid and a polylactic acid-based resin having lactic acid in a structural unit, a method as shown in Production Example 2 described below with reference to the method disclosed in JP-A-6-65360 Is mentioned.
That is, it is a direct dehydration condensation method in which lactic acid and / or a hydroxycarboxylic acid other than lactic acid, or an aliphatic diol and an aliphatic dicarboxylic acid are dehydrated and condensed as they are in the presence of an organic solvent and a catalyst.
As other reference examples of the method for producing a polylactic acid-based resin having lactic acid as a structural unit, for example, as shown in Production Examples 3 to 6 described later with reference to the method disclosed in JP-A-7-173266 A method is mentioned.
That is, it is a method in which at least two types of polylactic acid resin homopolymers are copolymerized and transesterified in the presence of a polymerization catalyst.
As another specific example of the method for producing polylactic acid, for example, a method as shown in Production Example 1 described later with reference to the method disclosed in US Pat. No. 2,703,316 may be mentioned.
That is, an indirect polymerization method in which lactic acid and / or a hydroxycarboxylic acid other than lactic acid is once dehydrated to form a cyclic dimer and then subjected to ring-opening polymerization.
[0029]
[Clearing agent]
The clarifying agent used in the present invention is a fatty acid ester represented by the general formula (1) [Chemical Formula 5].
[0030]
[Chemical formula 5]

(In the general formula (1), R¹, R²Is a saturated or unsaturated hydrocarbon having 1 to 30 carbon atoms, and is a linear or branched hydrocarbon group, and n is an integer of 1 to 4. )
Specific examples of fatty acid esters in the method of the present invention include dimethyl adipate, di-2-ethylhexyl adipate, diisobutyl adipate, dibutyl adipate, diisodecyl adipate, dibutyl diglycol adipate, di-2-ethylhexyl adipate, dibutyl sebacate, di- Examples include 2-ethylhexyl sebacate. In particular, diisodecyl adipate is preferred.
[0031]
[Amount of clarifying agent added]
The amount of the clarifying agent added to the polylactic acid resin can be 1 to 6% by weight with respect to the polylactic acid resin composition, preferably 1.5 to 5.5% by weight, more preferably Is 2.0 to 5.0% by weight.
If it is less than 1% by weight, the effect as a clarifying agent may be insufficient. Conversely, if it exceeds 6% by weight, the effect as a clarifying agent cannot be obtained, and it is transparent when crystallized. In some cases, the appearance and physical properties (rigidity) may change due to deterioration of properties.
[0032]
[Inorganic additives]
The molded product produced by the production method of the present invention has improved physical properties such as improved crystallization speed, improved heat resistance, improved mechanical properties and improved blocking resistance, as long as the transparency of the molded product is not impaired. In order to do so, an inorganic additive can be added.
Specific examples of the inorganic additive include talc, kaolinite, and SiO.₂And clay, etc., but it is necessary to select conditions (addition amount, particle size) as appropriate so as not to impair the transparency of the molded body. In order to maintain the transparency of the molded product, it is generally recommended to select a particle size substantially smaller than the wavelength of visible light.
[0033]
More specifically, for the purpose of improving physical properties of blocking resistance, for example, SiO having a particle diameter of 1 to 50 nm.₂Etc. are preferably used without impairing transparency.
In the production method of the present invention, when the purpose is to further improve the crystallization rate during molding such as crystallization in a mold during molding or crystallization by heat treatment of the formed molded body,₂A crystalline inorganic substance containing 10% by weight or more of components is preferable. Specifically, talc TM-30 (manufactured by Fuji Talc), kaolin JP-100 (manufactured by Tsuchiya Kaolin), NN kaolin clay (manufactured by Tsuchiya Kaolin) Kaolinite ASP-170 (manufactured by Fuji Talc), Kaolin UW (manufactured by Engelhard), Talc RF (manufactured by Fuji Talc), and the like. In this case, those having a small particle size and being well dispersed without being aggregated when melt-kneaded with a resin are preferably used.
[0034]
[Amount of inorganic additive]
The addition amount of the inorganic additive is preferably an amount that does not extremely impair the transparency of the molded body, and is 30% by weight or less, preferably 20% by weight or less, based on 100 parts by weight of the polylactic acid resin composition. It is preferably 10% by weight or less, more preferably 5% by weight or less, and most preferably 1% by weight or less.
[0035]
In the molded product produced by the production method of the present invention, various elastomers (SBR, NBR, SBS type ternary block copolymer thermoplastic elastomer, etc.) and additives (plastics) are used unless the transparency of the molded product is impaired. Agents, pigments, stabilizers, antistatic agents, ultraviolet absorbers, antioxidants, flame retardants, mold release agents, lubricants, dyes, antibacterial agents), fillers (impact core / shell particles, impact modifiers, etc.) ) And pigments (metallic pigments, pearl pigments) can be appropriately used depending on the purpose and application.
[0036]
[Molding method]
<Mixing / kneading / kneading>
In the present invention, a polylactic acid resin composition is prepared by mixing, kneading and kneading at least one clarifying agent selected from the compound group represented by the general formula (1) [Chemical Formula 5]. The manufacturing method employs a known and known kneading technique, for example, a method of mixing each raw material with a Henschel mixer, a ribbon blender or the like, or further kneading the molten polymer with liquid injection using an extruder or the like. be able to.
[0037]
<Molding>
Below, the method to manufacture the molded object which has both transparency and crystallinity which are the objectives of this invention is demonstrated.
The present invention is a method for producing a molded product having both transparency and crystallinity by crystallizing the above-described polylactic acid resin resin composition at the time of molding or after molding.
Examples of the molding method generally include ordinary methods such as injection molding, extrusion molding, blow molding, inflation molding, profile extrusion molding, injection blow molding, vacuum pressure molding, spinning, etc. In the resin composition shown in the present invention, Any molding method can be applied and there is no limitation.
In the present invention, it is necessary to crystallize the molded body by some method (for example, heat treatment) at the time of molding or after molding the polylactic acid resin composition. Specific examples thereof include, for example, a method in which a melt of the composition is filled in a mold at the time of molding and crystallized as it is in the mold (hereinafter referred to as in-mold crystallization method), and Examples thereof include a method of heat-treating an amorphous molded body (hereinafter referred to as a post-crystallization method). In the in-mold crystallization method and the post-crystallization method, optimum temperature conditions for crystallization of the molded product are different.
[0038]
(1) Temperature conditions for crystallization in the in-mold crystallization method
In the case of the in-mold crystallization method, the temperature setting condition of the mold is preferably a temperature range from the crystallization start temperature at the time of temperature drop to the crystallization end temperature in the differential scanning calorimetry of the composition. A temperature near the apex is more preferable. If the temperature is higher than the crystallization start temperature, the crystallization speed is remarkably reduced, and the productivity and operability are deteriorated. Further, the crystallization may not be performed, and the target molded product may not be obtained. At a temperature lower than the end temperature, the crystallization rate is remarkably small, and the intended molded article may not be obtained. In this method, the holding time in the mold varies depending on the composition, but there is no particular limitation as long as it is longer than the time required for the molded body to crystallize sufficiently in the mold.
[0039]
(2) Temperature conditions for crystallization in post-crystallization method
On the other hand, in the case of the post-crystallization method, the temperature setting condition of the mold is the temperature range from the glass transition temperature (Tg) to the melting point (Tm) of the composition, more preferably from (Tg + 5 ° C.) to (Tm-20 ° C.). ), More preferably (Tg + 10 ° C.) to (Tm−30 ° C.), most preferably (Tg + 15 ° C.) to (Tm−40 ° C.). When the set temperature is higher than Tm, transparency may be impaired or the shape may be distorted even if crystallization is performed in a short time, and further melting may occur when heated for a long time. On the other hand, at a temperature lower than Tg, the crystallization rate is remarkably small, and the target crystalline molded article may not be obtained. In this method, the time for heat-treating the molded body varies depending on the composition, but is not particularly limited as long as it is sufficient for the molded body to be sufficiently crystallized.
[0040]
<Aspect of a method for producing a molded article having both transparency and crystallinity>
Below, the aspect of the shaping | molding method of the molded object which can provide transparency and crystallinity to a molded object based on this invention simultaneously is demonstrated.
[0041]
(1) Injection molding (In-mold crystallization method)
In injection molding (in-mold crystallization method), for example, a clarification agent is added to the polylactic acid obtained in Production Example 2 to be described later, and the molten pellet of the composition is crystallized from the crystallization start temperature to the end of crystallization. By filling and holding in the metal mold | die hold | maintained within the temperature range of temperature, the molded object which has both transparency and crystallinity aimed at by this invention can be shape | molded.
[0042]
(2) Injection molding (post crystallization method)
In injection molding (post-crystallization method), for example, an amorphous molded body obtained by molding at a mold temperature of 20 ° C. using the pellets shown in (1) above is obtained from Tg (58 ° C.). An injection molded article having both transparency and crystallinity intended in the present invention can be formed by maintaining it in an atmosphere within a temperature range of Tm (165 ° C.) or by bringing it into contact with an appropriate heat medium. it can.
[0043]
(3) Extrusion molding (post crystallization method)
In extrusion molding (post-crystallization method), for example, an amorphous film or sheet obtained by molding the pellet shown in (1) above with a general T-die extrusion molding machine is used from Tg (58 ° C.) to Tm. Transparency intended in the present invention can be obtained by continuously passing through an oven (heating furnace) held in the range of (165 ° C.) or warm water and performing heat treatment, or performing batch heat treatment. A sheet or film having crystallinity can be formed.
[0044]
(4) Blow molding (post crystallization method)
In blow molding (post-crystallization method), after obtaining the amorphous preform by melting the pellet shown in (1) above with a general blow molding machine and filling the mold, The obtained preform is heated in an oven (heating furnace), then placed in a mold held within a range of Tg (58 ° C.) to Tm (165 ° C.), and pressurized air is sent out and blown. By doing so, the blow bottle which has both transparency and crystallinity aimed at by this invention can be shape | molded.
Here, when high-pressure [for example, room temperature (25 ° C.) or higher to Tm (165 ° C. or lower)] is used as the pressure air, the time required for crystallization of the molded body can be shortened.
[0045]
(5) Vacuum forming / vacuum / pressure forming (in-mold crystallization method)
The amorphous film formed by the same method as in the above (3) is vacuum-formed or vacuumed in a mold held within the range of the crystallization start temperature to the crystallization end temperature by a general vacuum forming machine. By performing pressure forming, a molded article having both transparency and crystallinity intended in the present invention can be formed.
Here, when high-pressure [for example, room temperature (25 ° C.) or higher to Tm (165 ° C. or lower)] is used as the pressure air, the time required for crystallization of the molded body can be shortened.
[0046]
(6) Vacuum forming / vacuum pressure forming (vacuum forming of crystalline film)
By forming the crystalline film formed by the same method as in the above (3) by vacuum / pressure forming, a molded article having both transparency and crystallinity intended in the present invention can be formed.
The polylactic acid-based resin molded article of the present invention obtained by molding by the molding method as described above has both crystallinity and transparency, and has high heat resistance.
[0047]
In the present invention, the polylactic acid-based resin molded article has transparency, so that when the molded article having a thickness of 1 mm and a newspaper are stacked, the letters of the newspaper can be recognized through the molded article. It means that the haze of the molded product having a thickness of 1 mm is 30% or less.
In the present invention, the fact that the polylactic acid-based resin molded product is heat resistant means that the crystallinity measured by the X-ray diffraction method is 10% or more.
That is, being heat resistant means that the Vicat softening point (Vicat softening temperature) is 100 to 160 ° C. in Vicat softening point (Vicat softening temperature) measurement (ASTM D1525).
By the production method of the present invention, a polylactic acid-based resin molded article having both crystallinity (heat resistance) and transparency having a crystallinity of 10% or more, a thickness of 1 mm and a haze of 30% or less is obtained.
According to the production method of the present invention, even when the degree of crystallinity is 30% or more, the crystallinity (heat resistance) with a haze of 30% or less, 20% or less, 15% or less, and even 10% or less at a thickness of 1 mm. A polylactic acid-based resin molded article having transparency is obtained.
[0048]
The polylactic acid-based resin molded body having transparency, crystallinity (heat resistance) and degradability of the present invention is an injection molded product, film, bag, tube, sheet, cup, bottle obtained by a publicly known molding method. It includes trays, threads, etc., and there are no restrictions on its shape, size, thickness, design, etc.
Specifically, the molded article of the present invention includes food packaging bags, tableware, forks, spoons, bottles for dairy products, soft drinks and alcoholic beverages, food containers such as wrap films, trays, bottles and films. , Cosmetic containers, garbage bags, bulk, (adhesive) tape, air mats, containers for bleach, daily miscellaneous goods such as bottles for liquid detergents, leisure goods such as tents and tarpaulins, medical equipment, medical materials Containers and packaging materials for pharmaceuticals, fishing lines, fish nets, containers and packaging materials and capsules for agricultural products, containers and packaging materials and capsules for fertilizers, containers and packaging materials and capsules for seedlings, agricultural and horticultural films, It can be used for a product packaging film, an overhead projection film, a heat ray reflective film, a liquid crystal display film, and the like.
[0049]
In addition, the film or sheet obtained by the method of the present invention is made into a multilayered structure by laminating or bonding with sheets of other materials such as paper and other polymers, and adhesive or heat fusion. You can also.
In particular, an amorphous film of a polylactic acid resin having excellent transparency such as polylactic acid or a copolymer having a polylactic acid block and a polybutylene succinate block has been thermally laminated on, for example, paper. In such a case, there is a problem that it becomes crystallized and opaque due to heat during lamination.
Therefore, in applications where transparency is required, heat treatment conditions during thermal lamination are preferably limited, or lamination methods using adhesives are preferably used, and furthermore, in applications where transparency and heat resistance are required. The resin composition could not be used.
However, when those resin compositions containing the clearing agent of the present invention are used, for example, a transparent amorphous film is directly heat-laminated on paper or the like, bonded to paper or the like, and crystals of the composition May be performed simultaneously.
Further, the laminated body once thermally laminated may be further heat-treated to be crystallized. Under any condition, it is possible to obtain a laminate that maintains its transparency and further imparts heat resistance.
[0050]
【Example】
The present invention is described in detail below with reference to production examples, examples and comparative examples.
It should be noted that the descriptions of synthesis examples, examples, comparative examples, aspects, etc. in the specification of the present application are explanations for supporting the understanding of the contents of the present invention, and the description narrows the technical scope of the present invention. It is not of a character that is the basis for interpretation.
[0051]
A. Production example
The manufacturing method of the polylactic acid-type resin used in an Example and a comparative example is shown below. In the text, all parts are based on weight.
The average molecular weight (weight average molecular weight Mw) of the polymer was measured by gel permeation chromatography using polystyrene as a standard under the following conditions.
(1) Equipment: Shimadzu LC-IOAD
(2) Detector: Shimadzu RID-6A
(3) Column: Hitachi Chemical GL-S350DT-5, GL-S370DT-5
(4) Solvent: Chloroform
▲ 5 ▼ Concentration: 1%
(6) Injection volume: 20μ1
[Production Example 1] <Production of polymer A (poly L-lactide)>
100 parts by weight of L-latatide, 0.01 part of stannous octoate and 0.03 part of lauryl alcohol were sealed in a thick cylindrical stainless steel polymerization vessel equipped with a stirrer and degassed by vacuum for 2 hours. Thereafter, it was replaced with nitrogen gas. The mixture was heated at 200 ° C. for 3 hours with stirring under a nitrogen atmosphere. While maintaining the temperature as it is, the inside of the reaction vessel was gradually depressurized to 3 mmHg by gradually deaeration with a vacuum pump through an exhaust pipe and a glass receiver. After 1 hour from the start of degassing, since the distillation of monomers and low molecular weight volatile components was stopped, the inside of the container was purged with nitrogen, the polymer was extracted from the lower part of the container into a strand shape, pelletized, and an L-lactide homopolymer (polymer A) was obtained. The yield was 78%, and the weight average molecular weight Mw was 130,000.
[0052]
[Production Example 2] <Production of polymer B (poly L-lactic acid)>
To a 100 liter reactor equipped with a Dien-Stark trap, 10 kg of 90% L-lactic acid was distilled at 150 ° C./50 mmHg for 3 hours while stirring for 3 hours, and then 6.2 g of tin powder was added. The mixture was further oligomerized by stirring at 30 mmHg for 2 hours. To this oligomer, 28.8 g of tin powder and 21.1 kg of diphenyl ether were added, and 150 ° C./35 mmHg azeotropic dehydration reaction was performed. The distilled water and the solvent were separated by a water separator, and only the solvent was returned to the reactor. After 2 hours, the organic solvent to be returned to the reactor was passed through a column packed with 46 kg of molecular sieve 3A and then returned to the reactor, and the reaction was carried out at 150 ° C./35 mmHg for 40 hours to obtain a weight average molecular weight of 1460,000. A solution of polylactic acid was obtained. To this solution, 44 kg of dehydrated diphenyl ether was added, diluted and cooled to 40 ° C., and the precipitated crystals were filtered, washed 3 times with 10 kg of n-hexane and dried at 60 ° C./50 mmHg. This powder was added with 12 kg of 0.5 N HCl and 12 kg of ethanol, stirred at 35 ° C. for 1 hour, filtered, dried at 60 ° C./50 mmHg, and white powder of polylactic acid 6. 1 kg (yield 85%) was obtained. The weight average molecular weight Mw of this polylactic acid (Polymer B) was 145,000.
[0053]
[Production Example 3] <Production of Copolymer C (Polybutylene Succinate / Polylactic Acid Copolymer)>
Diphenyl ether (293.0 g) was added to 50.5 g of 1,4-butanediol and 66.5 g of succinic acid, and 2.02 g of metal tin was added, and the mixture was oligomerized by heating and stirring while distilling water outside the system at 130 ° C./140 mmHg for 7 hours. . A Dean-Stark trap was attached to this, and azeotropic dehydration was carried out at 140 ° C./30 mmHg for 8 hours. Then, a tube filled with 40 g of molecular sieve 3A was attached, and the distilled solvent passed through the molecular sieve tube into the reactor. Then, the mixture was stirred at 130 ° C./17 mmHg for 49 hours. The reaction mass was dissolved in 600 ml of chloroform, added to 4 liters of acetone and reprecipitated, and then sludged with a solution of HCl in isopropyl alcohol (hereinafter abbreviated as IPA) (HCl concentration 0.7 wt%) for 0.5 hours (3 Times) and washed with IPA and then dried under reduced pressure at 60 ° C. for 6 hours to obtain polybutylene succinate (hereinafter abbreviated as PSB). The weight average molecular weight Mw of this polymer was 118,000.
80.0 g of the obtained polybutylene succinate was mixed with 120.0 g of polylactic acid obtained by the same method as in Production Example 2 (weight average molecular weight Mw is 20,000), diphenyl ether 800 g) and 0.7 g of metallic tin. Then, dehydration condensation reaction was performed again at 130 ° C./17 mmHg for 20 hours. After completion of the reaction, post-treatment was performed in the same manner as in Production Example 2 to obtain 188 g (yield 94%) of a copolymer of polybutylene succinate and polylactic acid. The weight average molecular weight Mw of the copolymer of polybutylene succinate and polylactic acid (copolymer C) was 14,000,000.
[0054]
[Production Example 4] <Production of copolymer D (polybutylene succinate / polylactic acid copolymer)>
The same procedure as in Production Example 3 was carried out except that 40.0 g of polybutylene succinate (weight average molecular weight Mw was 118,000) and polylactic acid 160.0 g (weight average molecular weight Mw was 50,000) were used. As a result, a copolymer of polybutylene succinate and polylactic acid (copolymer D) was obtained. The yield was 96%, and the weight average molecular weight Mw was 136,000.
[0055]
[Production Example 5] <Production of copolymer E (polybutylene succinate / polylactic acid copolymer)>
The same procedure as in Production Example 3 was carried out except that 20.0 g of polybutylene succinate (weight average molecular weight Mw was 118,000) and 180.0 g of polylactic acid (weight average molecular weight Mw was 10.0 million). As a result, a copolymer of polybutylene succinate and polylactic acid (copolymer E) was obtained. The yield was 94%, and the weight average molecular weight Mw was 142,000.
[0056]
[Production Example 6] <Production of copolymer F (polycaproic acid / polylactic acid copolymer)>
A reaction was carried out in the same manner as in Production Example 2 except that 6-hydroxycaproic acid was used in place of lactic acid. As a result, polycaproic acid (weight average molecular weight Mw was 150,000) was obtained. Next, 20.0 g of the obtained polycaproic acid and 180.0 g of polylactic acid (weight average molecular weight Mw is 10.0 million) were used in the same manner as in Production Example 4 to obtain a copolymer of polycaproic acid and polylactic acid (copolymer F). ) The yield was 92% and the weight average molecular weight Mw was 153,000.
[0057]
B. Evaluation methods
[Evaluation of physical properties]
The evaluation conditions of the physical properties of the molded bodies produced using the polylactic acid resin compositions obtained in Production Examples 1 to 6 are as follows.
(1) Transparency (Haze)
According to JIS K-6714, it measured using Tokyo Denshoku Haze Meter.
[0058]
(2) Crystallinity
The molded specimen was measured with an X-ray diffractometer (manufactured by Rigaku Corporation, Rint 1500 type), and the ratio of the crystal peak area of the obtained chart to the total area was determined.
(3) Heat resistance [Vicat softening temperature (ASTM-D1525)]
Measure the test piece after molding under the condition of 1 kgf load.
[0059]
(4) Crystallization start temperature, crystallization end temperature
The temperature at which the crystallization peak was observed when the shaped body was once melted with a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation) and the temperature was lowered at 10 ° C./min was the crystallization start temperature, The temperature at which no crystallization peak was observed was defined as the crystallization end temperature.
[0060]
(5) Glass transition temperature (Tg), melting point (Tm)
The point at which the molded body changes to a rubbery shape when heated by a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation) under the condition of 10 ° C./min is the glass transition point (Tg) and the peak of the melting peak. The melting point (Tm) was used.
[0061]
C. Examples and Comparative Examples
In the following examples, when the molded body is heat-treated, when it is crystallized at the time of temperature drop in the in-mold crystallization operation, it is within the range from the crystallization start temperature at the temperature drop to the crystallization end temperature or more. In the case where crystallization is performed at the time of temperature rise by a heat treatment operation after molding, the temperature is set within the temperature range from the glass transition temperature to the melting point.
[0062]
[Example 1 [Injection molding]]
After thoroughly mixing 95 parts by weight of the polylactic acid obtained in Production Example 2 and 5 parts by weight of diisodecyl adipate as a clarifying agent with a Henschel mixer, the mixture was pelletized under conditions of an extruder cylinder set temperature of 170 to 210 ° C. The pellets were melted under the conditions of a JSW-75 injection molding machine manufactured by Nippon Steel Works under a cylinder setting temperature of 180 to 200 ° C., filled in a mold with a setting temperature of 30 ° C., and the cooling time was 30 seconds. A 0 mm thick transparent smooth flat plate molded body was obtained. The flatness (haze) of this flat plate was 2%, the crystallinity was 0%, and the Vicat softening point was 58 ° C.
This flat plate was heat-treated in a dryer at 120 ° C./5 min. The obtained flat plate had a transparency (haze) of 6%, a crystallinity of 40%, and a Vicat softening point of 150 ° C. The results are shown in Table 1 [Table 1].
[0063]
[Examples 1-2 to 1-6 [injection molding]]
Except having changed the addition amount of a polymer and a clarifying agent as shown in Table-1 [Table 1], it carried out similarly to Example 1-1, and each obtained transparency (haze) and crystallization of the flat plate The Vicat softening point was measured. The results are shown in Table 1 [Table 1].
[0064]
[Comparative Examples 1-1 to 1-6 [Injection Molding]]
The same procedure as in Example 1 was performed except that the clarifying agent diisodecyl adipate was omitted. The transparency (haze), crystallinity, and Vicat softening point of each obtained flat plate were measured. The results are shown in Table-2 [Table 2].
[0065]
[Example 2-1 [Blow molding]]
The polylactic acid obtained in Production Example 2 as a polymer and 5% by weight of diisodecyl adipate as a clarifying agent were sufficiently mixed with a Henschel mixer, and then pelletized under conditions of an extruder cylinder set temperature of 170 to 210 ° C. The pellets are melted under the conditions of an injection blow molding machine (manufactured by Nissei ASB Machine, ASB-50) and a cylinder set temperature of 180 to 200 ° C., filled in a mold (A) with a set temperature of 20 ° C., and cooling time is 30 seconds. A 2.0 mm thick preform (bottomed parison) was obtained. The obtained parison was heated in a heating furnace to a parison temperature of 120 ° C. and placed in a mold (B) maintained at 120 ° C., and the pressure air pressure was 4 kgf / cm.²Vertical magnification under the conditions of
A container having an internal volume of 500 ml was obtained by doubling the width and doubling the weft. The transparency (haze) of the obtained container (thickness 0.5 mm) was 3% (7% when converted to 1 mm thickness haze), the crystallinity was 43%, and the Vicat softening point was 150 ° C.
[0066]
[Comparative Example 2-1 [Blow Molding]]
The same procedure as in Example 4 was performed except that the clarifying agent (diisodecyl adipate) was removed. The transparency (haze) of the obtained container (thickness 0.5 mm) was 75% (80% in terms of 1 mm thickness haze), the crystallinity was 45%, and the Vicat softening point was 150 ° C.
[0067]
[Comparative Example 2-2 [Blow Molding]]
The same procedure as in Example 4-1 was performed except that the parison temperature was 55 ° C. and the mold (B) temperature was 30 ° C. The transparency (haze) of the obtained container (thickness 0.5 mm) was 1.3% (3% when converted to a haze value of 1 mm thickness), the crystallinity was 0%, and the Vicat softening point was 59 ° C. .
[0068]
[Example 3-1 [extrusion molding]]
Polylactic acid carried in Production Example 1 as a polymer and 5% by weight of diisodecyl adipate as a clarifying agent were sufficiently mixed with a Henschel mixer, and then pelletized under conditions of an extruder cylinder set temperature of 170 to 210 ° C. The pellets were melted under the conditions of a T-die 50 mmφ extruder (manufactured by Frontier, die width 400 mm) and a cylinder set temperature of 180 to 200 ° C. to obtain a transparent 0.5 mm thick sheet at a die temperature of 185 ° C. The transparency (haze) of this sheet (thickness 0.5 mm) was 1% (2% when converted to a haze value of 1 mm thickness), and the crystallinity was 0%.
Further, the sheet was passed through a hot air dryer (temperature 100 ° C., residence time 2 min) continuously and heat-treated. The transparency of the obtained sheet was 3% (8% in terms of 1 mm thickness haze), and the crystallinity was 40%.
[0069]
[Comparative Example 3-1 [Extrusion Molding]]
The same procedure as in Example 5-1 was performed except that the clarifying agent diisodecyl adipate was omitted. The transparency (haze) of the obtained sheet was 73% (84% in terms of 1 mm thickness haze), and the crystallinity was 39%.
[0070]
[Comparative Example 3-2 [Extrusion Molding]]
The sheet (thickness 0.5 mm) obtained in Example 3-1 (having a haze value of 1% and a crystallinity of 0%) was heat-treated at a temperature of 55 ° C. for 20 minutes in a hot air dryer. The transparency (haze) of the obtained sheet (thickness 0.5 mm) was 1% (2% when converted to 1 mm thickness haze), and the crystallinity was 0%.
[0071]
[Example 4-1 [inflation molding]]
Using the polymer obtained in Production Example 4 (copolymer of polybutylene succinate and polylactic acid), 5 parts by weight of diisodecyl adipate as a clarifying agent was sufficiently mixed with a Henschel mixer, and then the extruder cylinder set temperature 170 Pelletization was performed under the condition of ~ 210 ° C.
The beret is melted under the conditions of an inflation molding machine (manufactured by Kawada Manufacturing Co., Ltd., 45 mmΦ) cylinder set temperature of 165 to 180 ° C., die temperature is 170 ° C., expansion ratio (BUR) is 2.5, and the folding diameter is 250 mm). An inflation film of 05 mm was obtained. The transparency (haze) of this film was 0.5% (3% in terms of 1 mm thickness haze), and the crystallinity was 0%.
Further, the obtained film was heat-treated with warm water (temperature 85 ° C., residence time 2 min). The transparency (haze) of this film (thickness 0.05 mm) was 0.7% (5% in terms of 1 mm thickness haze), and the crystallinity was 35%.
[0072]
[Comparative Example 4-1 [Inflation Molding]]
The same procedure as in Example 4-1 was performed except that the clarifying agent (diisodecyl adipate) was removed. The transparency (haze) of the obtained sheet (thickness 0.5 mm) was 43% (70% in terms of 1 mm thickness haze), and the crystallinity was 34%.
[0073]
[Example 5-1 [Profile extrusion molding]]
Polylactic acid obtained in Production Example 2 as a polymer and 5% by weight of diisodecyl adipate as a clarifying agent were sufficiently mixed with a Henschel mixer, and then pelletized under conditions of an extruder cylinder set temperature of 170 to 210 ° C. The pellets were melted under the conditions of an irregular die 40 mmΦ extruder (manufactured by Frontier, die hollow is a square hollow) cylinder set temperature of 180 to 200 ° C, extruded at a die temperature of 175 ° C, and a sizing box with a vacuum device (cooling temperature 30) C.) to obtain a hollow molded body having a thickness of 0.5 mm and an outer dimension of 40 mm × 30 mm. The transparency (haze) of this hollow body was 1.5% (2% in terms of 1 mm thickness haze), and the crystallinity was 0%.
Furthermore, the hollow body was continuously passed through a hot air dryer (temperature 100 ° C., residence time 2 min) and heat-treated to obtain a hollow body. The transparency (haze) of the obtained hollow body (thickness 0.5 mm) was 3.5% (8% when converted to 1 mm thickness haze), and the crystallinity was 41%.
[0074]
[Comparative Example 5-1 [Atypical Extrusion Molding]]
The same procedure as in Example 8 was performed except that the clarifying agent (diisodecyl adipate) was omitted. The obtained sheet (thickness 0.5 mm) had a transparency (haze) of 71% (77% when converted to a lmm-thick haze) and a crystallinity of 40%.
[0075]
[Example 6-1 [Vacuum / Pneumatic Forming-1; Molding of Crystallized Sheet]]
The polylactic acid obtained in Production Example 2 as a polymer and 5% by weight of diisodecyl adipate as a clarifying agent were mixed well in a Henschel mixer, and then pelletized under conditions of an extruder cylinder set temperature of 170 to 210 ° C. The pellet was melted under the conditions of a T die 50 mmΦ extruder (manufactured by Frontier, die width 400 mm) and a cylinder set temperature of 180 to 200 ° C. to obtain a sheet with a thickness of 0.25 mm at a die temperature of 185 ° C.
The transparency (haze) of this sheet (thickness: 0.25 mm) was 1.0% (2% in terms of 1 mm thickness haze), and the crystallinity was 0%. Further, the sheet was subjected to heat treatment by continuously passing it through a hot air dryer (temperature 100 ° C.) residence time 2 min). The transparency (haze) of the obtained sheet (thickness: 0.25 mm) was 2.5% (7% in terms of 1 mm thickness haze), and the crystallinity was 38%.
[0076]
Next, this sheet was softened at a heating temperature of 120 ° C. and a holding time of 30 seconds using a vacuum / pressure forming machine equipped with an elliptical mold having a major axis of 146 mm, a minor axis of 100 mm, and a depth of 30 mm, and the mold temperature was adjusted to 60 ° C. Pressurized air pressure 4kgf / cm on the above-mentioned elliptical mold²Thus, a compact was obtained by vacuum adhesion (decompression degree: 50 mmHg) for 10 seconds. The transparency (haze) of the molded body was 3% (8% in terms of 1 mm thickness haze), and the crystallinity was 40%.
[0077]
[Example 6-2 [Vacuum / Pneumatic Forming-2; Amorphous Sheet Crystallized in Mold]]
A sheet having a thickness of 0.25 mm (having a haze value of 0% and a crystallinity of 0%) obtained in Example 6-1 was used, and an elliptical mold having a major axis of 146 mm, a minor axis of 100 mm, and a depth of 30 mm was provided. Using a vacuum / pneumatic molding machine, heated at a heating temperature of 85 ° C) and softened with a holding time of 40 seconds, and the pressure of the air pressure was 1 kgf / cm.²Then, a compact was obtained by vacuum adhesion (decompression degree: 50 mmHg) for 1 minute.
The transparency (haze) of the molded product was 3% (8% in terms of 1 mm thickness haze), and the crystallinity was 41%.
[0078]
[Comparative Example 6-1]
The same procedure as in Example 6-2 was performed except that the clarifying agent (diisodecyl adipate) was removed. The obtained molded article had a transparency (haze) of 73% (82% in terms of lmm thickness haze) and a crystallinity of 42%.
[0079]
[Comparative Example 6-2]
The same procedure as in Example 6-2 was performed except that the mold temperature was changed to 55 ° C. The obtained molded body (thickness: 0.25 mm) had a transparency (haze) of 1% (2% when converted to a 1 mm-thick haze) and a crystallinity of 0%.
[0080]
[Table 1]

[0081]
[Table 2]

[0082]
【The invention's effect】
According to the present invention, it is possible to provide a polylactic acid resin molded article having both transparency and crystallinity (heat resistance) at the same time.

Claims (8)

A polylactic acid resin molded article containing a polylactic acid resin (A) and a clarifying agent (B) comprising diisodecyl adipate ,
Based on the total weight of the polylactic acid resin (A) and the clarifying agent (B), the polylactic acid resin (A) is 94 to 99% by weight, and the clarifying agent (B) is 6 to 6%. 1% by weight, and
And the equivalent transparency that the haze value of 1mm thickness is 30% or less, a crystallinity of not less than 30%, Vicat softening point having both a heat resistance equivalent to a 100 to 160 ° C. A polylactic acid resin molded product characterized by the above.   2. The polylactic acid resin is at least one selected from the group consisting of polylactic acid, a copolymer having a polylactic acid block and a polybutylene succinate block, and a copolymer having a polylactic acid block and a polycaproic acid block. The polylactic acid resin molded product described in 1. A method for producing a polylactic acid-based resin molding comprising a polylactic acid-based resin (A) and a clearing agent (B) comprising diisodecyl adipate ,
Based on the total weight of the polylactic acid resin (A) and the clarifying agent (B), the polylactic acid resin (A) is 94 to 99% by weight, and the clarifying agent (B) is 6 to 6%. When molding a polylactic acid resin composition containing 1% by weight, it is characterized by heat treatment at the time of molding or after molding,
And the equivalent transparency that the haze value of 1mm thickness is 30% or less, a crystallinity of not less than 30%, Vicat softening point having both a heat resistance equivalent to a 100 to 160 ° C. A method for producing a polylactic acid-based resin molded product. The heat treatment method is to melt the polylactic acid resin composition once, and then fill and crystallize the mold in a temperature range from the crystallization start temperature to the crystallization end temperature of the polylactic acid resin composition. The manufacturing method according to claim 3 , wherein: In the heat treatment method, the melt of the polylactic acid-based resin composition was cooled and solidified in a mold to obtain an amorphous molded body, and then the molded body was converted into a glass transition temperature Tg + 15 of the polylactic acid-based resin (A). ℃) to (
4. The production method according to claim 3 , wherein the crystallization is performed in a temperature range up to a melting point Tm-40 ° C. After the heat treatment method obtains an amorphous molded product of the polylactic acid resin composition, the molded product is obtained from (glass transition temperature Tg + 15 ° C.) to (melting point Tm−40 ° C.) of the polylactic acid resin (A). The manufacturing method according to claim 3 , wherein the crystallization is performed in a temperature range. Polylactic acid resin is polylactic acid, a copolymer having a polylactic acid block and polybutylene succinate block is at least one selected from the group consisting of a copolymer having a polylactic acid block and Porikapuron acid block, claim The production method according to any one of 3 to 6 . Transparency equivalent to a 1 mm thickness haze value of 30% or less obtained by the production method according to any one of claims 3 to 7 , crystallinity of 30% or more, and Vicat softening polylactic acid resin molded article where the points having both a heat resistance equivalent to a 100 to 160 ° C..