JP4997673B2 - Biodegradable resin composition and packaging container using the same - Google Patents

Description

式中、Ｒは水素原子、または直鎖或いは分岐鎖のアルキル基であり、
ｎはゼロを含む正の整数である、
で表される反復単位、例えば、
乳酸［Ｒ＝ＣＨ_３、ｎ＝０、ＬＬＡ］、
３−ヒドロキシブチレート［Ｒ＝ＣＨ_３、ｎ＝１、３ＨＢ］、
３−ヒドロキシバリレート［Ｒ＝ＣＨ_２ＣＨ_３、ｎ＝１、３ＨＶ］、
３−ヒドロキシカプロエート［Ｒ＝（ＣＨ_２）_２ＣＨ_３、ｎ＝１、３ＨＣ］、
３−ヒドロキシヘプタノエート［Ｒ＝（ＣＨ_２）_３ＣＨ_３、ｎ＝１、３ＨＨ］、
３−ヒドロキシオクタノエート［Ｒ＝（ＣＨ_２ ）_４ ＣＨ_３ ｎ＝１、３ＨＯ］、
３−ヒドロキシノナノエート［Ｒ＝（ＣＨ_２）_５ＣＨ_３、ｎ＝１、３ＨＮ］、
３−ヒドロキシデカノエート［Ｒ＝（ＣＨ_２）_６ＣＨ_３、ｎ＝１、３ＨＤ］、
γ−ブチロラクトン［Ｒ＝Ｈ、ｎ＝２、ＢＬ］、
δ−バレロラクトン［Ｒ＝Ｈ、ｎ＝３、ＶＬ］、
ε−カプロラクトン［Ｒ＝Ｈ、ｎ＝４、ＣＬ］
等の１種或いは２種以上からなる重合体が挙げられる。
【００１９】
このポリヒドロキシアルカノエートは、ポリ乳酸（ポリ乳酸としては、構成単位がＬ−乳酸のみからなるポリ（Ｌ−乳酸）、Ｄ−乳酸のみからなるポリ（Ｄ−乳酸）およびＬ−乳酸単位とＤ−乳酸種任意の割合で存在するポリ（ＤＬ−乳酸）を示す。）又、ポリεカプロラクトンのような単独重合体であってもよく、他のヒドロキシアルカリエートとの共重合体でもよい。また３−ヒドロキシブチレートと、他の３−ヒドロキシアルカノエート、特に３−ヒドロキシバリレートとを共重合させた共重合体であってもよい。
【００２０】
本発明に用いる脂肪族ポリエステルは、ガラス転移点（Ｔｇ）が−６０℃以上、特に３０℃以上のものが好ましい。
これらの脂肪族ポリエステルの内、工業的に量産され入手が容易であり、環境にも優しい脂肪族ポリエステルとして、ポリ乳酸が挙げられる。
ポリ乳酸（ＰＬＬＡ）は、トウモロコシなどの穀物デンプンを原料とする樹脂であり、デンプンの乳酸発酵物、Ｌ−乳酸をモノマーとする重合体である。一般にそのダイマーであるラクタイドの開環重合法、及び、直接重縮合法により製造される。この重合体は、自然界に存在する微生物により、水と炭酸ガスにより分解され、完全リサイクルシステム型の樹脂として着目されている。
また、そのガラス転移点（Ｔｇ）も約５８℃とＰＥＴのＴｇに近いという利点を有している。
【００２１】
本発明の目的に最も好適な生分解性樹脂は、構成単位が実質上Ｌ−乳酸から成り、光学異性体であるＤ−乳酸の含有量が４．０％以下のものである。
本発明に用いるポリ乳酸は、勿論これに限定されないが、１００００〜３０００００、特に２００００〜２５００００の範囲の重量平均分子量（Ｍｗ）を有することが好ましい。また密度１．２６〜１．２０ｇ／ｃｍ^３、融点１６０〜２００℃、メルトフローレート（ＡＳＴＭ Ｄ１２３８，１９０℃）２〜２０ｇ／１０分の範囲にあることが好ましい。
【００２２】
［板状フィラー］
本発明に用いる板状フィラーは、粒子構造が板状であって、板状の面に対して配向可能なものが使用される。この板状フィラーは、５以上、特に１０乃至４００のアスペクト比（面方向寸法／厚さ方向寸法の比）を有する無機フィラー或いは有機フィラーであることが好ましく、その粒子径（最大方向寸法）は一般に０．２乃至４００μｍ、特に０．５乃至２００μｍの範囲にあることが好ましい。
【００２３】
このような板状フィラーとしては、一般にフレークとして知られている有機或いは無機の充填剤や顔料が使用され、例えば天然或いは合成の鉱物、セラミックス、金属、樹脂或いはこれらの複合体が使用される。
無機の板状フィラーとしては、天然或いは合成の雲母（マイカ）、ガラスフレーク、セラミックフレーク、金属フレーク等が挙げられ、一方樹脂の板状フィラーとしては、生分解性樹脂の溶融温度で実質上溶融しない樹脂製フレーク等があげられる。
【００２４】
これらの板状フィラーの内でも、本発明においては光輝性を有する板状フィラーを用いることが包装容器の装飾効果の点で必要である。光輝性板状フィラーの特に好適なものとして、微粒子被覆パール顔料を挙げることができる。これらの光輝性顔料粒子は、何れも偏平であって、成形の際、面方向に平行に配向する傾向を有するものであり、特異な金属状光沢或いは真珠状光沢を有する。
【００２５】
微粒子被覆パール顔料としては、それ自体公知の任意の微粒子被覆パール顔料が何れも使用されるが、特に好適なものとして、雲母チタン顔料が挙げられる。干渉有彩色の発生を、雲母チタン顔料を例として説明すると、この雲母チタン顔料はアスペクト比の大きい雲母基体とこの雲母基体表面に形成された二酸化チタンの微粒子析出層（以下単にチタン層とも呼ぶ）とから成る。
【００２６】
この雲母チタン顔料に光線が入射するとチタン層の表面で入射して反射する光線と、チタン層と雲母基体との界面で入射して反射する光線とが干渉し、干渉光を生ずる。
【００２７】
チタン層の厚みと、光の干渉により生じる有彩色との間には一定の関係があり、この関係は下記表Ａの通りである。
【００２８】

【００２９】
雲母チタン顔料は、雲母（３Ａｌ_２Ｏ_３・Ｋ_２Ｏ・６ＳｉＯ_２・ｎＨ_２Ｏ ）の薄片状結晶を核とし、この核の上に酸化チタン水和物を析出させ、これを焼成して、二酸化チタンとしたものである。表面の二酸化チタン層は、アナターゼ型でもよいし、またルチル型であってもよい。
雲母は、劈開性を有し、厚さが１μｍ以下で、アスペクト比が５０以上と大きい薄片状の結晶であることが特徴であり、この表面に屈折率の大きいチタン顔料の薄層を形成させることにより、その層厚に応じて、表１に示すような有彩色の干渉色が得られるわけである。
【００３０】
光輝性顔料の他の例として、金属フレーク顔料、特にアルミフレーク顔料が挙げられる。アルミフレークとしては、リーフイング型のものでも、ノンリーフイング型のものでも使用できる。リーフイング型のものは、ステアリン酸のような高級脂肪酸で処理されたものであり、表面に浮く傾向はあるがややキラキラ感に欠ける傾向がある。一方、ノンリーフイング型のものは表面に浮く傾向は少ないが、見る角度によってキラキラ感が強い。
また、アルミフレークに微粒子や着色物質を付着させて、特異な色調のメタリック感を発現する、いわゆる着色アルミフレークも使用できる。
【００３１】
光輝性フレークの更に他の例として、樹脂製のグリッターと呼ばれるものを用いることもできる。このグリッターの代表的なものは、ポリエチレンテレフタレートフイルムにアルミニウムを蒸着し、有彩色の場合は、その上にさらに着色したものである。グリッターの色相としては、無色のもの、green, light green, royal blue, sky blue, light blue, pink, red, yellow 等の各種色相のものが使用される。
使用できるグリッターのサイズは、０．３ｍｍ×０．３ｍｍ以下のものが好ましい。グリッターのサイズが上記範囲を上回ると、生分解性樹脂中への分散が悪くなるので好ましくない。
【００３２】
［樹脂状乃至ワックス状分散剤］
本発明では、生分解性樹脂中に樹脂状乃至ワックス状分散剤が含浸された光輝性板状フィラーを分散させる。用いる樹脂状乃至ワックス状分散剤は、既に指摘したとおり、非極性基或いは更に極性基を備えたものである。このような樹脂状乃至ワックス状分散剤は、上記の基を有するワックス類、半固体状物質或いは樹脂からなっている。
【００３３】
ワックス類としては、一般に天然に産出するワックス類、例えばモンタンワックス、カルナウバワックス、綿蝋、蜜蝋、木蝋、羊毛蝋等や、鉱物系或いは合成系のワックス類が、単独或いは２種以上の組合せで使用される。
鉱物系或いは合成系のワックスとしては、飽和脂肪族炭化水素化合物を主体とするもので、通常分子量が２０００以下、好ましくは１０００以下、更に好ましくは８００以下のパラフィン系ワックスと呼ばれるものである。これら脂肪族炭化水素化合物としては、具体的にはドコサン、トリコサン、テトラコサン、トリアコンタン等の炭素数２２以上のｎ−アルカンあるいはこれらを主成分とした低級ｎ−アルカンとの混合物、石油から分離精製された所謂パラフィンワックス、エチレンあるいはエチレンと他のα−オレフィンとを共重合して得られる低分子量重合体である中・低圧ポリエチレンワックス、高圧法ポリエチレンワックス、エチレン共重合ワックスあるいは中・低圧法ポリエチレン、高圧法ポリエチレン等のポリエチレンを熱減成等により分子量を低下させたワックス及びそれらのワックスの酸化物あるいはマレイン酸変性等の酸化ワックス、マレイン酸変性ワックス等が挙げられる。
【００３４】
半固体状物質としては、植物油脂、動物油脂、鉱物油或いは合成油の少なくとも１種が挙げられる。油脂は、天然の動植物界に広く存在し、脂肪酸とグリセリンとのエステルを主成分とするものであり、例えばサフラワー油、大豆油、菜種油、パーム油、パーム核油、綿実油、ヤシ油、米糠油、ゴマ油、ヒマシ油、亜麻仁油、オリーブ油、桐油、椿油、落花生油、カポック油、カカオ油、木蝋、ヒマワリ油、コーン油などの植物性油脂及びイワシ油、ニシン油、イカ油、サンマ油などの魚油、肝油、鯨油、牛脂、牛酪脂、馬油、豚脂、羊脂などの動物性油脂の単独またはそれらを組合せが挙げられる。また、鉱物油としては、流動パラフィン、スピンドル油などが挙げられ、合成油としては、シリコーン油、エステル油、ジエステル油、ポリグリコール油、ポリフェニルエーテル油、リン酸エステル油、ポリクロロトリフルオロエチレン油、フルオロエステル油、ネオペンチルポリオールエステル油等が挙げられる。
【００３５】
半固体状物質としては、高級脂肪酸やその石鹸を用いることもできる。高級脂肪酸としては、炭素数１０乃至２２、特に１４乃至１８の飽和乃至不飽和脂肪酸、例えばカプリン酸、ウンデカン酸、ラウリン酸、ミリスチン酸、パルミチン酸、マーガリン酸、ステアリン酸、アラキン酸等の飽和脂肪酸、リンデル酸、ツズ酸、ペトロセリン酸、オレイン酸、リノール酸、リノレン酸、アラキドン酸等の不飽和脂肪酸等が使用される。ステアリン酸が好適なものである。脂肪酸は勿論牛脂脂肪酸、ヤシ油脂肪酸、パーム油脂肪酸等の混合脂肪酸であってもよい。また、石鹸としては、上記脂肪酸のナトリウム石鹸、カリウム石鹸、アンモニウム石鹸、アミン石鹸、カルシウム石鹸、マグネシウム石鹸、亜鉛石鹸等を用いることもできる。
【００３６】
樹脂としては、オレフィンを構成単位として含有し且つ極性基を有する単量体単位を含む共重合樹脂が好適に使用される。
このような極性基含有オレフィン重合体としては、エチレン−酢酸ビニル共重合体、エチレン−アクリル酸共重合体、エチレン−メタクリル酸メチル共重合体、イオン架橋オレフィン共重合体（アイオノマー）、エチレン系不飽和カルボン酸乃至その無水物でグラフト変性されたオレフィン樹脂等の変性オレフィン樹脂やこれらの樹脂を含有するブレンド物を挙げることができる。
酸変性オレフィン樹脂のベースポリマーとしては、低−、中−、高−密度ポリエチレン、線状低密度ポリエチレン、アイソタクティックポリプロピレン、プロピレン−エチレン共重合体、エチレン−酢酸ビニル共重合体などが挙げられる。
【００３７】
［樹脂組成物］
本発明の樹脂組成物は、生分解性樹脂１００重量部当たり板状フィラーを２乃至７０重量部、特に５乃至６０重量部、樹脂状乃至ワックス状分散剤を０．０５乃至２０重量部、特に０．１乃至１０重量部含有する。
【００３８】
板状フィラーの含有量が上記範囲を下回ると、板状フィラーを用いることによるガスバリアー性の改善が不十分となり、外観性能の向上も望めなくなる。一方板状フィラーの配合量が上記範囲を上回ると、樹脂組成物の物性が脆くなる傾向があり、容器の耐衝撃性が低下するので好ましくない。
また、樹脂状乃至ワックス状分散剤の含有量が上記範囲を下回ると、板状フィラーの分散性が低下し、樹脂状乃至ワックス状分散剤が上記範囲内にある場合に比して、やはりガスバリアー性や外観特性が低下する傾向がある。一方樹脂状乃至ワックス状分散剤が上記範囲を上回ると、樹脂組成物の機械的特性や熱的特性が上記範囲内にある場合に比して劣る傾向があり、容器の物性の点で好ましくない。
【００３９】
本発明の樹脂組成物を形成する順序は、板状フィラーと樹脂状乃至ワックス状分散剤とを予めブレンドし、このブレンド物を生分解性樹脂と混合する。
【００４０】
各成分のブレンドには、ドライブレンドやメルトブレンドを用いることができっる。例えば、ドライブレンドには、ヘンシェルミキサー、ホモミキサー等を使用することができ、またメルトブレンドには、各種ニーダー、バンバリーミキサー、ロール、１軸或いは２軸押出機などを用いることができる。
【００４１】
本発明の樹脂組成物には、その用途に応じて、各種着色剤、充填剤、無機系或いは有機系の補強剤、滑剤、アンチブロッキング剤、可塑剤、レベリング剤、界面活性剤、増粘剤、減粘剤、安定剤、抗酸化剤、紫外線吸収剤等を、公知の処方に従って配合することができる。
【００４２】
また、本発明の樹脂組成物においては、上記生分解性樹脂の他に他の樹脂、特にガスバリアー性樹脂をブレンドして使用することもできる。
例えば、このような他の樹脂としては熱可塑性ポリビニルアルコール、エチレン・ビニルアルコール共重合体、メタキシリレンアジパミド（ＭＸＤ６）のような酸素バリアー性樹脂やポリグリコール酸乃至ポリグリコール酸共重合体樹脂の生分解性バリアー性樹脂や、環状オレフィン共重合体等の水蒸気バリアー性樹脂をブレンドして用いることができる。
ガスバリアー性樹脂は、生分解性樹脂１００重量部当たり０．１乃至４９重量部、特に０．５乃至３０重量部の量で用いることが好ましい。
【００４３】
本発明に用いる包装材料及び包装容器は、前述した樹脂組成物を用いる点を除けば、それ自体公知の方法で製造が可能である。
例えば、フィルム、シート或いはチューブの成形は、前記樹脂組成物を押出機で溶融混練した後、Ｔ−ダイ、サーキュラーダイ（リングダイ）等を通して所定の形状に押出すことにより行われ、Ｔ−ダイ法フィルム、ブローウンフィルム等が得られる。Ｔダイフィルムはこれを二軸延伸することにより、二軸延伸フィルムが形成される。
また、前記樹脂組成物を射出機で溶融混練した後、射出金型中に射出することにより、容器や容器製造用のプリフォームを製造することができる。
更に、前記樹脂組成物を押出機を通して、一定の溶融樹脂塊に押し出し、これを金型で圧縮成形することにより、容器や容器製造用のプリフォームを製造する。
成形物は、フイルム、シート、ボトル乃至チューブ形成用パリソン乃至はパイプ、ボトル乃至チューブ成形用プリフォーム等の形をとり得る。
【００４４】
本発明の包装材料及び包装容器においては、板状フィラーが樹脂状乃至ワックス状分散剤を介して生分解性樹脂中に微細且つ一様に分散した分散構造をとること、この樹脂組成物では、フィラーの板状形状及び上記の分散構造にも関連して、溶融成形時の流動配向や延伸時の延伸配向により板状フィラーが面方向に有効に配向した配向構造をとることが認められる。
このため、本発明の包装材料及び包装容器では、水分等の気体に対するガスバリアー性に顕著に優れていると共に、光輝性のある均一な外観が得られるなど、外観特性、商品価値の点においても顕著に優れている。
【００４５】
パリソン、パイプ或いはプリフォームからのボトルの形成は、押出物を一対の割型でピンチオフし、その内部に流体を吹込むことにより容易に行われる。
また、パイプ乃至はプリフォームを冷却した後、延伸温度に加熱し、軸方向に延伸すると共に、流体圧によって周方向にブロー延伸することにより、延伸ブローボトル等が得られる。
更に、また、フイルム乃至シートを、真空成形、圧空成形、張出成形、プラグアシスト成形等の手段に付することにより、カップ状、トレイ状等の包装容器が得られる。
【００４６】
フィルム等の包装材料は、種々の形態の包装袋として用いることができ、その製袋は、それ自体公知の製袋法で行うことができ、三方或いは四方シールの通常のパウチ類、ガセット付パウチ類、スタンディングパウチ類、ピロー包装袋などが挙げられるが、この例に限定されない。
【００４７】
本発明の生分解性樹脂組成物は、単層の形で包装材料及び包装容器として使用できるのは勿論のこと、この生分解性樹脂組成物から成る少なくとも一層と、他の樹脂からなる少なくとも一層の積層物の形で包装材料及び包装容器として使用できる。
【００４８】
多層構成の包装材料及び包装容器の場合、上記生分解性樹脂組成物層と組み合わせる他の樹脂層としては、板状フィラー未配合の生分解性樹脂、オレフィン系樹脂、熱可塑性ポリエステル樹脂、ガスバリアー性樹脂等が挙げられる。
オレフィン樹脂としては、低密度ポリエチレン（ＬＤＰＥ）、中密度ポリエチレン（ＭＤＰＥ）、高密度ポリエチレン（ＨＤＰＥ）、線状低密度ポリエチレン（ＬＬＤＰＥ）、線状超低密度ポリエチレン（ＬＶＬＤＰＥ）、アイソタクテイツクポリプロピレン（ＰＰ）、エチレン−プロピレン共重合体、ポリブテン−１、エチレン−ブテン−１共重合体、プロピレン−ブテン−１共重合体、エチレン−プロピレン−ブテン−１共重合体、エチレン−酢酸ビニル共重合体、イオン架橋オレフィン共重合体（アイオノマー）或いはこれらのブレンド物等が挙げられる。
また、熱可塑性ポリエステル樹脂としては、ポリエチレンフタレート（ＰＥＴ）、ポリブチレンテレフタレート（ＰＢＴ）、ポリエチレンナフタレート（ＰＥＮ）、或いはこれらの共重合ポリエステル、更にはこれらのブレンド物等が挙げられる。
更に、バリヤー性樹脂の最も適当な例としては、エチレン−ビニルアルコール共重合体（ＥＶＯＨ）を挙げることができ、例えば、エチレン含有量が２０乃至６０モル％、特に２５乃至５０モル％であるエチレン−酢酸ビニル共重合体を、ケン化度が９６モル％以上、特に９９モル％以上となるようにケン化して得られる共重合体ケン化物が使用される。このエチレンビニルアルコール共重合体ケン化物は、フイルムを形成し得るに足る分子量を有するべきであり、一般に、フエノール：水の重量比で８５：１５の混合溶媒中３０℃で測定して0.01 dｌ／g 以上、特に0.05 dｌ／g 以上の粘度を有することが望ましい。
更にまた、バリアー性樹脂の他の例としては、環状オレフィン系共重合体（ＣＯＣ）、特にエチレンと環状オレフィンとの共重合体、特に三井化学社製のＡＰＥＬ等や生分解性バリアー樹脂、ポリグリコール酸またはポリグリコール酸共重合体樹脂を用いることができる。
【００４９】
多層押出成形体の製造には、それ自体公知の共押出成形法を用いることができ、例えば樹脂の種類に応じた数の押出機を用いて、多層多重ダイを用いる以外は上記と同様にして押し出し成形を行えばよい。
また、多層射出成形体の製造には、樹脂の種類に応じた数の射出成形機を用いて、共射出法や逐次射出法により多層射出成形体を製造することができる。
更に、多層フィルムや多層シートの製造には、押出コート法や、サンドイッチラミネーションを用いることができ、また、予め形成されたフィルムのドライラミネーションによって多層フィルムあるいはシートを製造することもできる。
【００５０】
本発明の包装容器は、水分の透過による内容物の減量を抑制し、シェルフライフを向上させる容器として有用である。
充填できる内容物としては、飲料ではビール、ワイン、フルーツジュース、炭酸ソフトドリンク等、食品では果物、ナッツ、野菜、肉製品、幼児食品、コーヒー、ジャム、マヨネーズ、ケチャップ、食用油、ドレッシング、ソース類、佃煮類、乳製品類等、その他では医薬品、化粧品、トイレタリー製品などが挙げられるが、これらの例に限定されない。
【００５１】
【実施例】
本発明を次の例により更に説明するが、本発明はこれらの実施例に制限されるものでない。尚、実施例１及び実施例４は、本発明の範囲外の参考例である
【００５２】
（材料）
重量平均分子量（Ｍｗ）が１９００００で光学活性異性体(d%)組成が２．５％のポリ乳酸を用いた。板状無機材に、平均アスペクト比２００で平均厚み０．６μmの板状雲母、表面を二酸化チタン処理した光輝性板状雲母、ならびに、光輝性板状雲母に常温で粘着性のオレフィンワックスを含浸させた板状無機材を用いた。
【００５３】
（ボトル成形）
重量平均分子量（Ｍｗ）が１９００００で光学活性異性体(d%)組成量が２．５％のポリ乳酸を用いた。平均アスペクト比２００で平均厚０．６μmの板状雲母、表面を二酸化チタン処理した光輝性板状雲母、ならびに、光輝性板状雲母に常温で粘着性のオレフィンワックスを含浸させた板状無機材をそれぞれ５重量％添加した樹脂組成物を用い、射出成形機にて、バレル温度１９０℃〜２１０℃範囲下、口径２８mmφのプリフォームを射出成形した。次に、赤外線ヒーターでプリフォームを７０℃以上に加熱後、金型温度を９０℃とした金型ブロー成形を行い、４００ml容の角形ボトルを成形した。
【００５４】
（カップ成形）
重量平均分子量（Ｍｗ）が１９００００で光学活性異性体(d%)組成量が２．５％のポリ乳酸を用い、表面を二酸化チタン処理した平均アスペクト比２００の平均厚０．６μmの光輝性板状雲母に常温で粘着性のオレフィンワックスを含浸させた板状無機充填剤を５重量％添加した樹脂組成物を、押し出し成形機にて、バレル温度１９０℃〜２１０℃、Tダイ温度190℃条件下、４００mm幅で２mm厚シートを成形した。次にサーモフォーム成形機を用い、７０℃以上加熱後、円錐形プラグアシストで縦方向に延伸するとともに圧縮空気にて、９０℃の雌型に圧着し、口径８０mmφ、底径５０mmφ、高さ９０mmの円柱状カップを成形した。
【００５５】
（フィルム成形）
押し出し成形機を用い、バレル温度１９０℃〜２１０℃、Ｔダイ温度１９０℃条件下、平均アスペクト比２００で平均厚み０．６μmの板状雲母、表面を二酸化チタンで処理した光輝性板状雲母、ならびに、光輝性板状雲母に常温で粘着性のオレフィンワックスを含浸させた板状無機材を５重量％〜５０重量％範囲でドライブレンドした樹脂組成物を用い、押し出し成形機にて、８００mm幅、３００μm厚フィルムを成形した。
【００５６】
更に、ポリ乳酸樹脂８５重量％と第２のバリアー材エチレンビニルアルコール共重合樹脂１０重量％からなる樹脂組成物に、表面を二酸化チタン処理した平均アスペクト比２００の平均厚０．６μmの光輝性板状雲母に常温で粘着性のオレフィンワックスを含浸させた板状無機材を５重量％ドライブレンドした樹脂組成物を、押し出し成形機にて、８００mm幅、３００μm厚フィルムを成形した。
【００５７】
（評価）
水分バリアーの測定
（ボトル）
試作ボトルに水道水を３５０ml充填後、ポリプロピレン製キャップで密栓後、２２℃-ＲＨ６０％条件に保存した。以後、１４日後に重量測定し、水分透過率(%)を測定した。
（フィルム）
試作フィルムをParmatran水分透過性試験装置を用い、４０℃-ＲＨ９０%条件下、水分透過係数（Ｐ）（ｇｃｍ／ｍ²／ｄａｙ）を求めた。
【００５８】
（評価）
酸素バリアーの測定
（ボトル）
試作ボトルをガス置換装置で脱気後、窒素ガスを充填し、次に、水道水を１０ml充填後、ゴム栓で密封した。以後、２２℃-ＲＨ６０％条件に保存し、２１日後にガスクロマトグラフィー装置で、ボトル内酸素濃度を測定することで、BO_２(cc/day・bottle)を求めた。
【００５９】
（評価）板状無機材の分散性
ボトル・フィルム・カップ成形品における板状無機材の分散性を目視観察した。10mm×10mmの面内にサイズ1mm角以上の無機固形分の個数が１５個以上確認されたボトル・フィルム・カップを×とし、無機固形分の固まりがないボトル・フィルム・カップを○とした。尚、10mm×10mmの面内に1mm角以上の無機固形分の個数が15個未満観察されたボトル・フィルムを△とした。
【００６０】
（評価）成形性
９０℃金型でブロー成形した直後のボトル（角形）の底コーナー部にヒケが生じたボトルを×とし、ヒケの形成が生じていないボトルを○とした。
【００６１】
（評価）ボトル落下強度
試作ボトルに水道水を３５０ml充填、ポリプロピレン製キャップで密栓し、５℃条件に２４時間保存した。以後、1.2m高さから正立落下させ、ボトル底部に生じる剥離状割れを目視観察した。ボトル底部に剥離状割れが生じたボトルを×とし、剥離状割れが観測されないボトルを○とした。
【００６２】
［実施例１］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸９５重量％に、表面を二酸化チタン処理した平均アスペクト比２００の平均厚０．６μmの光輝性板状雲母を５重量％ドライブレンドした。この樹脂組成物を射出成形機にてプリフォームに射出成形した。次に、赤外線ヒーターにてプリフォームを７０℃以上に加熱後、９０℃金型温度で角形ボトルにブロー成形した。成形直後のボトルは、底コーナー部にヒケがなく、板状無機充填材の分散性は△であった。又、酸素バリアー性、水分透過性、並びに、落下試験結果を表-1に示した。
【００６３】
［実施例２］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸９５重量％に、表面を二酸化チタン処理した平均アスペクト比２００の平均厚０．６μmの光輝性板状雲母にオレフィン系ワックスを光輝性板状雲母に比し１０重量％含浸させた板状無機材を５重量％ドライブレンドした。この樹脂組成物を射出成形機でプリフォームに射出成形した。次に、赤外線ヒーターにてプリフォームを７０℃以上に加熱後、９０℃金型温度で角形ボトルにブロー成形した。成形直後のボトルは、底コーナー部にヒケがなく、板状無機充填材の分散性は○であった。又、酸素バリアー性、水分透過性、並びに、落下試験結果を表-1に示した。
【００６４】
［比較例１］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸を用い、射出成形機でプリフォームに射出成形した。次に、赤外線ヒーターにてプリフォームを７０℃以上に加熱後、９０℃金型温度で角形ボトルにブロー成形した。成形直後のボトルは、底コーナー部にヒケを生じた。又、酸素バリアー性、水分透過性、並びに、落下試験結果を表-1に示した。
【００６５】
［比較例２］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸９５重量％に、平均アスペクト比２００の平均厚０．６μmの板状雲母を５重量％ドライブレンドした。この樹脂組成物を射出成形機でプリフォームに射出成形した。次に、赤外線ヒーターにてプリフォームを７０℃以上に加熱後、９０℃金型温度で角形ボトルにブロー成形した。成形直後のボトルは、底コーナー部の一部にヒケが生じ、板状無機充填材の分散性も×であった。又、酸素バリアー性、水分透過性、並びに、落下試験結果を表-1に示した。
【００６６】
［実施例３］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸９５重量％に、表面を二酸化チタン処理した光輝性板状雲母にオレフィン系ワックスを光輝性板状雲母に比し１０重量％含浸させた平均アスペクト比２００の平均厚０．６μmの板状無機材を５重量％ドライブレンドした。この樹脂組成物を押し出し成形機を用い、シートに成形した。次に、サーモフォーム成形機を用い、カップを成形した。板状無機充填材の分散性が○であった。
【００６７】
［実施例４］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸９５重量％に、表面を二酸化チタン処理した平均アスペクト比２００の平均厚０．６μmの光輝性板状雲母を５重量％ドライブレンドした。この樹脂組成物を、押し出し成形機を用いフィルムに成形した。板状無機材の分散性は△であった。又、水分透過係数（Ｐ）を表-２に示した。
【００６８】
［実施例５］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸９５重量％に、表面を二酸化チタン処理した平均アスペクト比２００の平均厚０．６μmの光輝性板状雲母にオレフィン系ワックスを光輝性板状雲母に比し１０重量％含浸させた板状無機材を５重量％ドライブレンドした。この樹脂組成物を、押し出し成形機を用いフィルムに成形した。板状無機材の分散性は○であった。又、水分透過係数（Ｐ）を表-２に示した。
【００６９】
［実施例６］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸５０重量％に、表面を二酸化チタン処理した平均アスペクト比２００の平均厚０．６μmの光輝性板状雲母にオレフィン系ワックスを光輝性板状雲母に比し１０重量％含浸させた板状無機材を５０重量％ドライブレンドした。この樹脂組成物を、押し出し成形機を用いフィルムに成形した。板状無機材の分散性は○であった。又、水分透過係数（Ｐ）を表-２に示した。
【００７０】
［実施例７］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸８５重量％と第２のバリアー材エチレンビニルアルコール共重合体樹脂１０重量％からなる樹脂組成物に、表面を二酸化チタン処理した平均アスペクト比２００の平均厚０．６μmの光輝性板状雲母にオレフィン系ワックスを光輝性板状雲母材に比し１０重量％含浸させた板状無機材を５重量％ドライブレンドした。この樹脂組成物を、押し出し成形機を用いフィルムに成形した。板状無機材の分散性は○であった。又、水分透過係数（Ｐ）を表-２に示した。
【００７１】
［比較例３］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸９５重量％に、平均アスペクト比２００の平均厚０．６μmの板状雲母を５重量％ドライブレンドした。この樹脂組成物を、押し出し成形機を用いフィルムに成形した。板状無機材の分散性は×であった。又、水分透過係数（Ｐ）を表-２に示した。
【００７２】
［比較例４］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸８５重量％と第２のバリアー材エチレンビニルアルコール共重合体樹脂１０重量％からなる樹脂組成物に、平均アスペクト比２００の平均厚み０．６μmの板状雲母を５重量％ドライブレンドした。この樹脂組成物を、押し出し成形機を用いフィルムに成形した。板状無機材の分散性は×であった。又、水分透過係数（Ｐ）を表-２に示した。
【００７３】
［比較例５］
光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸８５重量％と第２のバリアー材エチレンビニルアルコール共重合体樹脂１０重量％からなる樹脂組成物に、表面を二酸化チタン処理した平均アスペクト比２００の平均厚０．６μmの光輝性板状雲母にオレフィン系ワックスを光輝性板状雲母に比し５０重量％含有させた板状無機材を５重量％ドライブレンドした。この樹脂組成物を、押し出し成形機を用いフィルムに成形した。この場合、フィルムは、ワックス分離層による層分離が形成し、全体的に不均一分散であった。このため、この比較例条件下では、板状無機材の分散性を×とした。又、水分透過係数（Ｐ）を表-２に示した。
【００７４】
［実施例８］
共射出成形機を用い、ファーストショットにて、光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸を用いプリフォームに射出成形後、セカンドショットでプリフォーム外層側に、光学活性異性体(d%)がｄ=2.5%で重量平均分子量（Ｍｗ）が１９００００のポリ乳酸に対し、表面を二酸化チタン処理した平均アスペクト比２００の平均厚０．６μmの光輝性板状雲母にポリオレフィン系ワックスを光輝性板状雲母に比し１０重量％含浸させた板状無機材を４０重量％ドライブレンドした樹脂組成物を、射出成形した。次に、次に、赤外線ヒーターにてプリフォームを７０℃以上に加熱後、９０℃金型温度で角形ボトルにブロー成形した。この場合、成形ボトルは層間剥離もなく、所定の形状に成形することができた。
【００７５】
【表１】

【００７６】
【表２】

【００７７】
【発明の効果】
本発明によれば、生分解性樹脂に樹脂状乃至ワックス状分散剤が含浸された光輝性板状フィラーと樹脂状乃至ワックス状分散剤とを含有させることにより、生分解性樹脂への板状添加剤の分散性を顕著に向上させることができ、この樹脂組成物の成形時における板状添加剤の面方向への配向性も顕著に向上させることができる。更に、第２のバリアー性樹脂を含有することで顕著なガスバリアー性向上が確保された。本発明の生分解性樹脂組成物は、樹脂状乃至ワックス状分散剤が含浸された光輝性板状フィラーを含有するにもかかわらず、成形性に優れており、しかも成形体の機械的強度や耐衝撃性に顕著に優れており、更に水分に対するバリアー性を含めてガスバリアー性や外観特性が顕著に向上させることができる。
【図面の簡単な説明】
【図１】生分解性樹脂（ポリ乳酸）に板状フィラー（二酸化チタン被覆フレーク顔料）を配合したときの配合量と水分透過量との関係を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a biodegradable resin composition and a packaging container comprising the same, and more specifically, has excellent dispersibility of fillers for improving gas barrier properties, and has excellent gas barrier properties and excellent appearance characteristics. The present invention relates to a biodegradable resin composition capable of forming a packaging container.
[0002]
[Prior art]
As an ideal solution for plastic waste, degradable plastics that have disappeared in the natural environment have attracted attention. Among them, biodegradable plastics that have been destroyed by the action of enzymes released from the body by bacteria and fungi have been used. Yes.
[0003]
However, although this biodegradable plastic is excellent in terms of harmony with the environment such as biodegradability, it can still be sufficiently satisfied in terms of performance such as gas barrier properties and moldability when used as a packaging container, for example. It was not a thing.
For this reason, blending various materials with biodegradable resins has long been performed.
[0004]
JP-A-6-65484 (Patent No. 2570551) relating to the proposal of the present inventors includes (A) a saturated polyester resin mainly composed of a hydroxyalkanoate unit, and (B) a vinyl alcohol polymer. (C) A resin composition containing an ethylene-vinyl acetate copolymer in a homogeneous state is described.
[0005]
JP-A-8-2517 discloses a resin comprising a biodegradable resin layer formed using a biodegradable resin and an added biodegradable resin layer obtained by adding an inorganic substance to the biodegradable resin. A container is described, and it is also described that talc, mica, titanium oxide and the like are used in an amount of 5 to 50% by weight as inorganic substances.
[0006]
Japanese Patent Application Laid-Open No. 2000-6230 describes a biodegradable resin container formed by injection blow molding a biodegradable resin to which a plate-like additive is added. It is also described that mica-based inorganic materials are suitable, with a blending amount of ˜35% by weight.
[0007]
[Problems to be solved by the invention]
The above proposal aims to improve the gas barrier property, particularly the moisture barrier property, which is a drawback of the biodegradable resin, by blending the biodegradable resin with polyvinyl alcohol or a mica-based additive. The problem is that the dispersibility of the additive to the biodegradable resin is low, so that the moldability is low, the mechanical strength and gas barrier properties of the molded body are still insufficient, and the appearance characteristics of the container are also inferior. is there.
[0008]
Therefore, the object of the present invention is to significantly improve the dispersibility of the plate-like additive in the biodegradable resin and to improve the orientation of the plate-like additive during molding of the resin composition. It is in providing a conductive resin composition.
Another object of the present invention is that it has excellent moldability despite the fact that it contains a plate-like filler, and is remarkably excellent in the mechanical strength and impact resistance of the molded product, and further has a barrier property against moisture. In addition, the present invention provides a packaging container having significantly improved gas barrier properties and appearance characteristics and a resin composition for producing the packaging container.
[0009]
[Means for Solving the Problems]
  According to the present invention, a biodegradable resin andBrightness impregnated with resinous or waxy dispersantA biodegradable resin composition comprising a plate-like filler is provided. In the biodegradable resin composition of the present invention,
1. 2 to 70 parts by weight of plate-like filler and 100 to 20 parts by weight of resinous or waxy dispersant per 100 parts by weight of biodegradable resin,
2. The biodegradable resin is an aliphatic polyester containing hydroxyalkanoate units;
3. The plate filler is an inorganic filler or an organic filler having an aspect ratio of 5 or more,
4). Plate fillerTwoBeing a titanium oxide coated flake pigment,
5). The resinous or waxy dispersant has a melting point or softening point lower than the melting point of the biodegradable resin;
6). Further containing a gas barrier resin;
7). In the above case, the gas barrier resin is preferably contained in an amount of 2 to 49 parts by weight per 100 parts by weight of the biodegradable resin.
  According to the present invention, there is further provided a packaging container formed from the biodegradable resin composition. In the packaging container of the present invention,
1. The plate-like filler in the biodegradable resin composition is oriented in the surface direction of the wall surface constituting the container,
2. The resin constituting the vessel wall is preferably biaxially oriented.
  According to the present invention, there is also provided a multilayer packaging container comprising at least one layer composed of the biodegradable resin composition.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
[Action]
  The resin composition of the present invention comprises a biodegradable resin andBrightness impregnated with resinous or waxy dispersantAlthough it contains a plate-like filler, according to the present invention, by including a resinous or waxy dispersant in the composition, the gas barrier property of the resin composition is improved, and the appearance as a packaging container The characteristics can be remarkably improved. Furthermore, the gas barrier property can be remarkably improved by containing a gas barrier resin.
[0011]
Please refer to FIG. 1 of the accompanying drawings. FIG. 1 shows the relationship between the amount of platy filler and the amount of moisture permeation for an unstretched sample of a resin composition in which a platy filler (titanium dioxide-coated flake pigment) is blended with a biodegradable resin (polylactic acid). For example). In FIG. 1, black circles (●) show the results when only the plate-like filler is blended, and white circles (○) show the results when the OH-containing resin is blended together with the plate-like filler.
[0012]
According to this result, the amount of moisture permeation of the resin composition monotonously decreases as the amount of the plate filler added to the biodegradable resin increases, but the degree of the decrease is rather gradual. Understood.
On the other hand, when the OH-containing resin is blended together with the plate-like filler, the amount of moisture permeation can be considerably reduced compared to the case where only the plate-like filler is blended, and this reduction amount is shown in the drawing. In the case of a specific example, it turns out that it is comparable to addition of a plate-like filler almost twice.
[0013]
In particular, in the case of a resin composition in which a resinous or waxy dispersant is blended together with a plate-like filler, an excellent brilliant appearance close to metallic luster is obtained. Compared to the above, the appearance characteristics of the packaging container are remarkably improved.
[0014]
In particular, the above-described effects of the blending of the resinous or waxy dispersant in the present invention are peculiar to the combination of the biodegradable resin and the plate-like filler. This is because it enables fine and uniform dispersion in the degradable resin and facilitates the orientation of the plate filler in the resin composition in the surface direction of the container wall during molding into a container. It is done.
[0015]
The present invention is by no means restricted by the following considerations, but the following can be considered as reasons for improving the dispersibility and orientation of the plate filler.
In general, the reason that the gas barrier property of the resin composition is improved by blending the plate-like filler in the resin is that the gas exists so as to bypass the plate-like filler due to the presence of the plate-like filler in the resin composition. The passage distance of the gas becomes long, and as a result, the gas permeation amount decreases.
[0016]
However, the biodegradable resin is a typical polar group-containing polymer, and the presence of this polar group is considered to be a cause of poor moisture barrier properties.
On the other hand, the plate-like filler is considered to have a polar site where the charge is not saturated at the edge of the particle structure, and to form an agglomerated structure by suction repulsion of these polar sites. It is believed that the agglomerated structure of the filler is larger and coarser due to the interaction with the biodegradable resin.
On the other hand, the resinous or waxy dispersant used in the present invention has a nonpolar group (long chain aliphatic hydrocarbon group) or a combination of a nonpolar group and a polar group. The presence of the group seems to be helpful in improving the dispersibility of the plate-like filler and promoting alignment by eliminating or mitigating the occurrence of the aggregation structure of the plate-like filler or the aggregate structure of the plate-like filler and biodegradable resin. It is.
[0017]
[Biodegradable resin]
In the present invention, known biodegradable resins can be used, but particularly important are aliphatic polyester resins, more specifically, biodegradable aliphatic polyester resins mainly composed of hydroxyalkanoate units. used. The aliphatic polyester resin should have at least a molecular weight capable of forming a film, and generally has a weight average molecular weight in the range of 10,000 to 300,000, particularly 20,000 to 250,000.
Examples of suitable aliphatic polyester resins are polyhydroxyalkanoates or copolymers thereof.
[0018]
The polyhydroxyalkanoate has the following formula:
[Chemical 1]

In the formula, R is a hydrogen atom or a linear or branched alkyl group,
n is a positive integer including zero,
A repeating unit represented by
Lactic acid [R = CH₃, N = 0, LLA],
3-hydroxybutyrate [R = CH₃, N = 1, 3HB],
3-hydroxyvalerate [R = CH₂CH₃, N = 1, 3HV],
3-hydroxycaproate [R = (CH₂)₂CH₃, N = 1, 3HC],
3-hydroxyheptanoate [R = (CH₂)₃CH₃, N = 1, 3HH],
3-hydroxyoctanoate [R = (CH₂ )₄ CH₃ n = 1, 3HO],
3-hydroxynonanoate [R = (CH₂)₅CH₃, N = 1, 3HN],
3-hydroxydecanoate [R = (CH₂)₆CH₃, N = 1, 3HD],
γ-butyrolactone [R = H, n = 2, BL],
δ-valerolactone [R = H, n = 3, VL],
ε-caprolactone [R = H, n = 4, CL]
The polymer which consists of 1 type, or 2 or more types, etc. is mentioned.
[0019]
This polyhydroxyalkanoate is composed of polylactic acid (as polylactic acid, poly (L-lactic acid) whose structural unit is composed only of L-lactic acid, poly (D-lactic acid) composed of only D-lactic acid, and L-lactic acid units and D -Poly (DL-lactic acid) present in an arbitrary proportion of lactic acid species.) Also, it may be a homopolymer such as poly-ε-caprolactone or a copolymer with other hydroxyalkaliates. Further, it may be a copolymer obtained by copolymerizing 3-hydroxybutyrate and other 3-hydroxyalkanoate, particularly 3-hydroxyvalerate.
[0020]
The aliphatic polyester used in the present invention preferably has a glass transition point (Tg) of -60 ° C or higher, particularly 30 ° C or higher.
Among these aliphatic polyesters, polylactic acid is an example of an aliphatic polyester that is industrially mass-produced and easily available and is also environmentally friendly.
Polylactic acid (PLLA) is a resin made from cereal starch such as corn, and is a lactic acid fermentation product of starch and a polymer containing L-lactic acid as a monomer. In general, the dimer is produced by a ring-opening polymerization method of lactide and a direct polycondensation method. This polymer is decomposed by water and carbon dioxide by microorganisms that exist in nature, and has attracted attention as a completely recycle system type resin.
In addition, the glass transition point (Tg) has an advantage of about 58 ° C., which is close to the Tg of PET.
[0021]
The most suitable biodegradable resin for the purpose of the present invention has a constitutional unit consisting essentially of L-lactic acid and a content of D-lactic acid which is an optical isomer of 4.0% or less.
Of course, the polylactic acid used in the present invention is not limited to this, but preferably has a weight average molecular weight (Mw) in the range of 10,000 to 300,000, particularly 20,000 to 250,000. The density is 1.26 to 1.20 g / cm³, Melting point 160 to 200 ° C., melt flow rate (ASTM D1238, 190 ° C.) 2 to 20 g / 10 min.
[0022]
[Plate filler]
The plate-like filler used in the present invention has a particle structure that is plate-like and can be oriented with respect to the plate-like surface. This plate-like filler is preferably an inorganic filler or an organic filler having an aspect ratio of 5 or more, particularly 10 to 400 (surface ratio / thickness ratio), and the particle diameter (maximum dimension) is In general, it is preferably in the range of 0.2 to 400 μm, particularly 0.5 to 200 μm.
[0023]
As such a plate-like filler, organic or inorganic fillers or pigments generally known as flakes are used. For example, natural or synthetic minerals, ceramics, metals, resins, or composites thereof are used.
Examples of inorganic platy fillers include natural or synthetic mica (mica), glass flakes, ceramic flakes, metal flakes, etc., while resin platy fillers are substantially melted at the melting temperature of the biodegradable resin. Resin flakes that do not.
[0024]
  Among these plate-like fillers, in the present invention, it is possible to use a plate-like filler having a glitter property in terms of the decorative effect of the packaging container.is necessary. A particularly preferable example of the glittering plate-like filler is a fine particle-coated pearl pigment. These glitter pigment particles are all flat and have a tendency to be oriented parallel to the surface direction during molding, and have a unique metallic luster or pearl luster.
[0025]
As the fine particle-coated pearl pigment, any arbitrary fine particle-coated pearl pigment known per se is used, and particularly preferred is a mica titanium pigment. The generation of interference chromatic colors will be described by taking a mica titanium pigment as an example. This mica titanium pigment is a mica substrate having a large aspect ratio, and a titanium dioxide fine particle deposited layer (hereinafter also simply referred to as a titanium layer) formed on the surface of the mica substrate. It consists of.
[0026]
When light enters the mica titanium pigment, the light incident and reflected on the surface of the titanium layer interferes with the light incident and reflected at the interface between the titanium layer and the mica substrate to generate interference light.
[0027]
There is a certain relationship between the thickness of the titanium layer and the chromatic color generated by light interference, and this relationship is as shown in Table A below.
[0028]

[0029]
Mica titanium pigment is mica (3Al₂O₃・ K₂O · 6SiO₂・ NH₂O 2) flaky crystals are used as nuclei, titanium oxide hydrate is deposited on the nuclei, and this is baked to form titanium dioxide. The surface titanium dioxide layer may be anatase type or rutile type.
Mica is characterized by being a flaky crystal having a cleavage property, a thickness of 1 μm or less and an aspect ratio of 50 or more, and a thin layer of a titanium pigment having a high refractive index is formed on this surface. Thus, chromatic interference colors as shown in Table 1 are obtained according to the layer thickness.
[0030]
Other examples of glitter pigments include metal flake pigments, particularly aluminum flake pigments. As the aluminum flake, either a leafing type or a non-leafing type can be used. The leafing type is processed with a higher fatty acid such as stearic acid, and tends to float on the surface, but tends to lack a slightly glittery feeling. On the other hand, the non-leafing type has little tendency to float on the surface, but has a strong glitter feeling depending on the viewing angle.
In addition, so-called colored aluminum flakes can be used in which fine particles or colored substances are attached to aluminum flakes to develop a metallic feeling with a unique color tone.
[0031]
As still another example of the glitter flakes, a so-called glitter made of resin can be used. A typical example of the glitter is a film obtained by vapor-depositing aluminum on a polyethylene terephthalate film, and in the case of a chromatic color, it is further colored thereon. As the hue of the glitter, those having various hues such as colorless, green, light green, royal blue, sky blue, light blue, pink, red and yellow are used.
The size of the glitter that can be used is preferably 0.3 mm × 0.3 mm or less. If the size of the glitter exceeds the above range, it is not preferable because dispersion in the biodegradable resin becomes worse.
[0032]
[Resin or waxy dispersant]
  In the present invention, in the biodegradable resinDisperse glittering platy filler impregnated with resinous or waxy dispersant. As already pointed out, the resinous or waxy dispersant used has a nonpolar group or a further polar group. Such resinous or waxy dispersants are composed of waxes having the above groups, semi-solid substances or resins.
[0033]
The waxes are generally naturally occurring waxes such as montan wax, carnauba wax, cotton wax, beeswax, wood wax, wool wax, and mineral or synthetic waxes, alone or in combination of two or more. Used in.
Mineral or synthetic waxes are mainly composed of saturated aliphatic hydrocarbon compounds and are usually called paraffinic waxes having a molecular weight of 2000 or less, preferably 1000 or less, more preferably 800 or less. As these aliphatic hydrocarbon compounds, specifically, a mixture with n-alkanes having 22 or more carbon atoms such as docosane, tricosane, tetracosane, triacontane, etc., or a mixture with lower n-alkanes containing these as main components, refined from petroleum So-called paraffin wax, medium or low pressure polyethylene wax, high pressure polyethylene wax, ethylene copolymer wax or medium / low pressure polyethylene which is a low molecular weight polymer obtained by copolymerizing ethylene or ethylene and other α-olefins Examples thereof include waxes whose molecular weight is reduced by heat degradation such as high pressure polyethylene, oxides of these waxes, oxidized waxes such as maleic acid modified, maleic acid modified waxes and the like.
[0034]
Examples of the semi-solid substance include at least one of vegetable oil, animal oil, mineral oil, and synthetic oil. Oils and fats are widely present in the natural animal and plant kingdoms, and are mainly composed of esters of fatty acids and glycerin. For example, safflower oil, soybean oil, rapeseed oil, palm oil, palm kernel oil, cottonseed oil, coconut oil, rice bran Oil, sesame oil, castor oil, linseed oil, olive oil, tung oil, coconut oil, peanut oil, kapok oil, cacao oil, wood wax, sunflower oil, corn oil and other vegetable oils and oils, herring oil, squid oil, saury oil, etc. And animal oils such as fish oil, liver oil, whale oil, beef tallow, beef tallow, horse oil, pork tallow and sheep tallow alone or in combination. Mineral oils include liquid paraffin, spindle oil, etc., and synthetic oils include silicone oil, ester oil, diester oil, polyglycol oil, polyphenyl ether oil, phosphate ester oil, polychlorotrifluoroethylene. Oil, fluoroester oil, neopentyl polyol ester oil, and the like.
[0035]
As the semi-solid substance, higher fatty acids and soaps thereof can be used. As higher fatty acids, saturated fatty acids having 10 to 22 carbon atoms, particularly 14 to 18 carbon atoms, such as capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, etc. , Unsaturated fatty acids such as lindelic acid, tuzuic acid, petrothelic acid, oleic acid, linoleic acid, linolenic acid and arachidonic acid. Stearic acid is preferred. Of course, the fatty acid may be a mixed fatty acid such as beef tallow fatty acid, coconut oil fatty acid, or palm oil fatty acid. Further, as the soap, sodium fatty acid soap, potassium soap, ammonium soap, amine soap, calcium soap, magnesium soap, zinc soap and the like can be used.
[0036]
As the resin, a copolymer resin containing a monomer unit containing an olefin as a structural unit and having a polar group is suitably used.
Examples of such polar group-containing olefin polymers include ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-methyl methacrylate copolymers, ion-crosslinked olefin copolymers (ionomers), ethylene-based polymers. Examples thereof include modified olefin resins such as olefin resins graft-modified with saturated carboxylic acids or anhydrides thereof, and blends containing these resins.
Examples of the base polymer of the acid-modified olefin resin include low-, medium-, and high-density polyethylene, linear low density polyethylene, isotactic polypropylene, propylene-ethylene copolymer, and ethylene-vinyl acetate copolymer. .
[0037]
[Resin composition]
The resin composition of the present invention comprises 2 to 70 parts by weight, particularly 5 to 60 parts by weight of a plate-like filler, and 0.05 to 20 parts by weight of a resinous or waxy dispersant, particularly 100 parts by weight of a biodegradable resin. Contains 0.1 to 10 parts by weight.
[0038]
When the content of the plate-like filler is below the above range, the improvement of gas barrier properties due to the use of the plate-like filler becomes insufficient, and the appearance performance cannot be improved. On the other hand, if the amount of the plate filler exceeds the above range, the physical properties of the resin composition tend to be brittle, and the impact resistance of the container is lowered, which is not preferable.
Further, when the content of the resinous or waxy dispersant is below the above range, the dispersibility of the plate-like filler is lowered, and as compared with the case where the resinous or waxy dispersant is within the above range, the gas is also gas. There is a tendency for barrier properties and appearance characteristics to deteriorate. On the other hand, if the resinous or waxy dispersant exceeds the above range, the mechanical properties and thermal properties of the resin composition tend to be inferior to those in the above range, which is not preferable in terms of physical properties of the container. .
[0039]
  Order of forming the resin composition of the present inventionIsA plate-like filler and a resinous or waxy dispersant are blended in advance, and this blend is combined with a biodegradable resin.Mix.
[0040]
A dry blend or a melt blend can be used for blending each component. For example, a Henschel mixer, a homomixer, or the like can be used for dry blending, and various kneaders, Banbury mixers, rolls, single screw or twin screw extruders can be used for melt blending.
[0041]
In the resin composition of the present invention, various colorants, fillers, inorganic or organic reinforcing agents, lubricants, antiblocking agents, plasticizers, leveling agents, surfactants, thickeners are used depending on the application. , Thickeners, stabilizers, antioxidants, ultraviolet absorbers and the like can be blended according to known formulations.
[0042]
Further, in the resin composition of the present invention, in addition to the biodegradable resin, other resins, in particular, gas barrier resins can be blended and used.
Examples of such other resins include thermoplastic polyvinyl alcohol, ethylene / vinyl alcohol copolymer, oxygen barrier resin such as metaxylylene adipamide (MXD6), and polyglycolic acid or polyglycolic acid copolymer. A resin biodegradable barrier resin and a water vapor barrier resin such as a cyclic olefin copolymer can be blended and used.
The gas barrier resin is preferably used in an amount of 0.1 to 49 parts by weight, particularly 0.5 to 30 parts by weight per 100 parts by weight of the biodegradable resin.
[0043]
The packaging material and packaging container used in the present invention can be produced by a method known per se, except that the above-described resin composition is used.
For example, the film, sheet or tube is formed by melt-kneading the resin composition with an extruder and then extruding it into a predetermined shape through a T-die, a circular die (ring die), etc. Method film, blown film, etc. are obtained. The T-die film is biaxially stretched to form a biaxially stretched film.
Moreover, after melt-kneading the said resin composition with an injection machine, it can inject | pour into an injection die, and can manufacture the preform for container and container manufacture.
Further, the resin composition is extruded into a certain molten resin mass through an extruder, and compression molded with a mold to produce a container and a preform for producing the container.
The molded product may take the form of a film, sheet, bottle or tube forming parison or pipe, bottle or tube forming preform, and the like.
[0044]
In the packaging material and the packaging container of the present invention, the resin filler takes a dispersion structure in which the plate-like filler is finely and uniformly dispersed in the biodegradable resin via a resinous or waxy dispersant. In relation to the plate shape of the filler and the above-described dispersion structure, it is recognized that the plate-like filler has an orientation structure in which the plate-like filler is effectively oriented in the plane direction by the flow orientation during melt molding and the stretch orientation during stretching.
For this reason, the packaging material and the packaging container of the present invention are remarkably excellent in gas barrier properties against gases such as moisture, and also have a lustrous and uniform appearance. Remarkably superior.
[0045]
Formation of a bottle from a parison, pipe or preform is easily performed by pinching off the extrudate with a pair of split molds and blowing a fluid into the inside.
Further, after cooling the pipe or the preform, it is heated to a stretching temperature, stretched in the axial direction, and blow-stretched in the circumferential direction by a fluid pressure to obtain a stretch blow bottle or the like.
Furthermore, a cup or tray-like packaging container can be obtained by subjecting the film or sheet to means such as vacuum forming, pressure forming, bulging forming, or plug assist forming.
[0046]
Packaging materials such as film can be used as packaging bags of various forms, and the bags can be produced by a known bag making method. Ordinary pouches with three- or four-side seals, pouches with gussets. , Standing pouches, pillow packaging bags, and the like, but are not limited to this example.
[0047]
The biodegradable resin composition of the present invention can be used as a packaging material and a packaging container in the form of a single layer, as well as at least one layer composed of this biodegradable resin composition and at least one layer composed of another resin. It can be used as a packaging material and packaging container in the form of a laminate.
[0048]
In the case of multi-layer packaging materials and packaging containers, other resin layers combined with the biodegradable resin composition layer include biodegradable resins not containing a plate-like filler, olefin resins, thermoplastic polyester resins, gas barriers. Resin etc. are mentioned.
Examples of the olefin resin include low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), linear very low density polyethylene (LVLDPE), isotactic polypropylene ( PP), ethylene-propylene copolymer, polybutene-1, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer And an ion-crosslinked olefin copolymer (ionomer) or a blend thereof.
Examples of the thermoplastic polyester resin include polyethylene phthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), copolymerized polyesters thereof, and blends thereof.
Further, the most suitable example of the barrier resin is an ethylene-vinyl alcohol copolymer (EVOH). For example, ethylene having an ethylene content of 20 to 60 mol%, particularly 25 to 50 mol%. -A saponified copolymer obtained by saponifying a vinyl acetate copolymer so that the saponification degree is 96 mol% or more, particularly 99 mol% or more is used. The saponified ethylene vinyl alcohol copolymer should have a molecular weight sufficient to form a film and is generally 0.01 dl / measured at 30 ° C. in a 85:15 weight ratio of phenol: water. It is desirable to have a viscosity of g or more, particularly 0.05 dl / g or more.
Furthermore, other examples of the barrier resin include cyclic olefin copolymers (COC), particularly copolymers of ethylene and cyclic olefins, especially APEL manufactured by Mitsui Chemicals, biodegradable barrier resins, poly Glycolic acid or polyglycolic acid copolymer resins can be used.
[0049]
For the production of a multilayer extrusion molded body, a known coextrusion molding method can be used. For example, the number of extruders corresponding to the type of resin is used, and a multilayer multiple die is used in the same manner as described above. Extrusion molding may be performed.
Further, in the production of a multilayer injection molded article, a multilayer injection molded article can be produced by a co-injection method or a sequential injection method using a number of injection molding machines corresponding to the type of resin.
Furthermore, for the production of a multilayer film or a multilayer sheet, an extrusion coating method or sandwich lamination can be used, and the multilayer film or sheet can also be produced by dry lamination of a film formed in advance.
[0050]
The packaging container of the present invention is useful as a container that suppresses the weight loss of the contents due to moisture permeation and improves shelf life.
Contents that can be filled include beer, wine, fruit juice, carbonated soft drink for beverages, fruit, nuts, vegetables, meat products, infant food, coffee, jam, mayonnaise, ketchup, cooking oil, dressing, sauces for food , Boiled foods, dairy products, etc., and others include pharmaceuticals, cosmetics, toiletry products, etc., but are not limited to these examples.
[0051]
【Example】
  The invention is further illustrated by the following examples, but the invention is not limited to these examples.Examples 1 and 4 are reference examples outside the scope of the present invention.
[0052]
(material)
Polylactic acid having a weight average molecular weight (Mw) of 190,000 and an optically active isomer (d%) composition of 2.5% was used. Plate-like inorganic material is impregnated with plate-like mica with an average aspect ratio of 200 and an average thickness of 0.6 μm, glittering plate-like mica whose surface is treated with titanium dioxide, and glittering plate-like mica at room temperature. The plate-shaped inorganic material made to use was used.
[0053]
(Bottle molding)
Polylactic acid having a weight average molecular weight (Mw) of 190,000 and an optically active isomer (d%) composition of 2.5% was used. Plate-like mica having an average aspect ratio of 200 and an average thickness of 0.6 μm, glittering plate-like mica whose surface is treated with titanium dioxide, and a sheet-like inorganic material obtained by impregnating glittering plate-like mica with an olefin wax that is sticky at room temperature A preform having a diameter of 28 mmφ was injection-molded at a barrel temperature of 190 ° C. to 210 ° C. using an injection molding machine. Next, after the preform was heated to 70 ° C. or higher with an infrared heater, the mold was blow-molded at a mold temperature of 90 ° C. to form a 400 ml square bottle.
[0054]
(Cup molding)
A glittering plate having an average aspect ratio of 200 and an average thickness of 0.6 μm, using polylactic acid having a weight average molecular weight (Mw) of 190,000 and an optically active isomer (d%) composition of 2.5% and having a surface treated with titanium dioxide. A resin composition in which 5% by weight of a plate-like inorganic filler impregnated with a sticky olefin wax at room temperature is added to a glassy mica is subjected to conditions of barrel temperature 190 ° C. to 210 ° C. and T die temperature 190 ° C. in an extrusion molding machine. Below, a 2 mm thick sheet having a width of 400 mm was formed. Next, using a thermoform molding machine, after heating at 70 ° C or higher, it is stretched in the longitudinal direction with a conical plug assist and pressed against a female mold at 90 ° C with compressed air. A cylindrical cup was formed.
[0055]
(Film forming)
Using an extrusion machine, plate mica having an average aspect ratio of 200 and an average thickness of 0.6 μm under a barrel temperature of 190 ° C. to 210 ° C. and a T die temperature of 190 ° C., a glittering plate mica whose surface is treated with titanium dioxide, In addition, using a resin composition obtained by dry blending a platy inorganic material impregnated with glossy platy mica at room temperature with an adhesive olefin wax in the range of 5 wt% to 50 wt%, an extrusion molding machine is used to obtain a width of 800 mm. A 300 μm thick film was formed.
[0056]
Further, a glittering plate having an average aspect ratio of 200 and an average thickness of 0.6 μm, obtained by treating the surface of the resin composition comprising 85% by weight of polylactic acid resin and 10% by weight of the second barrier material ethylene vinyl alcohol copolymer resin with titanium dioxide. A resin composition obtained by dry blending 5% by weight of a plate-like inorganic material impregnated with olefin wax adhesive at room temperature into a glassy mica was formed into an 800 mm wide and 300 μm thick film using an extruder.
[0057]
(Evaluation)
Moisture barrier measurement
(Bottle)
The prototype bottle was filled with 350 ml of tap water, sealed with a polypropylene cap, and stored under conditions of 22 ° C. and RH 60%. Thereafter, the weight was measured after 14 days, and the water permeability (%) was measured.
(the film)
Using a Parmatran moisture permeability tester for the prototype film, moisture permeability coefficient (P) (gcm / m²/ Day).
[0058]
(Evaluation)
Oxygen barrier measurement
(Bottle)
The prototype bottle was degassed with a gas displacement device, filled with nitrogen gas, then filled with 10 ml of tap water and sealed with a rubber stopper. After that, the sample was stored at 22 ° C.-RH 60%, and after 21 days, the oxygen concentration in the bottle was measured with a gas chromatography device.₂(cc / day · bottle) was calculated.
[0059]
(Evaluation) Dispersibility of plate-like inorganic material
The dispersibility of the plate-like inorganic material in the bottle / film / cup molded product was visually observed. Bottles, films, and cups in which 15 or more inorganic solids having a size of 1 mm square or more in a 10 mm × 10 mm surface were confirmed as “x”, and bottles, films, and cups having no solid inorganic solids as “◯”. A bottle film in which less than 15 inorganic solids of 1 mm square or more were observed in a 10 mm × 10 mm plane was indicated by Δ.
[0060]
(Evaluation) Formability
A bottle with sink marks at the bottom corner of a bottle (rectangular shape) immediately after blow molding with a 90 ° C. mold was marked with ×, and a bottle with no sink marks formed was marked with ◯.
[0061]
(Evaluation) Bottle drop strength
The prototype bottle was filled with 350 ml of tap water, sealed with a polypropylene cap, and stored at 5 ° C. for 24 hours. Thereafter, it was dropped upright from a height of 1.2 m, and the peeled crack generated at the bottom of the bottle was visually observed. A bottle in which a peel-off crack was generated at the bottom of the bottle was rated as x, and a bottle in which no peel-off crack was observed was marked as ◯.
[0062]
[Example 1]
A glittering plate having an average aspect ratio of 200 and an average thickness of 0.6 μm obtained by treating 95% by weight of polylactic acid having an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000 with titanium dioxide. 5% by weight of dry mica was dry blended. This resin composition was injection molded into a preform with an injection molding machine. Next, the preform was heated to 70 ° C. or higher with an infrared heater and then blow-molded into a square bottle at a mold temperature of 90 ° C. The bottle immediately after molding had no sink at the bottom corner, and the dispersibility of the plate-like inorganic filler was Δ. Table 1 shows the oxygen barrier properties, moisture permeability, and drop test results.
[0063]
[Example 2]
A glittering plate having an average aspect ratio of 200 and an average thickness of 0.6 μm obtained by treating 95% by weight of polylactic acid having an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000 with titanium dioxide. A plate-like inorganic material impregnated with olefinic wax in an amount of 10% by weight with respect to the glossy plate-like mica was dry-blended with 5% by weight. This resin composition was injection molded into a preform with an injection molding machine. Next, the preform was heated to 70 ° C. or higher with an infrared heater and then blow-molded into a square bottle at a mold temperature of 90 ° C. The bottle immediately after molding had no sink marks at the bottom corner, and the dispersibility of the plate-like inorganic filler was good. Table 1 shows the oxygen barrier properties, moisture permeability, and drop test results.
[0064]
[Comparative Example 1]
Polylactic acid having an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000 was used for injection molding into a preform by an injection molding machine. Next, the preform was heated to 70 ° C. or higher with an infrared heater and then blow-molded into a square bottle at a mold temperature of 90 ° C. The bottle immediately after molding had sink marks at the bottom corner. Table 1 shows the oxygen barrier properties, moisture permeability, and drop test results.
[0065]
[Comparative Example 2]
Dry blend of 95% polylactic acid with an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000, and 5% by weight of plate-like mica with an average aspect ratio of 200 and an average thickness of 0.6 μm did. This resin composition was injection molded into a preform with an injection molding machine. Next, the preform was heated to 70 ° C. or higher with an infrared heater and then blow-molded into a square bottle at a mold temperature of 90 ° C. The bottle immediately after molding had sink marks at a part of the bottom corner, and the dispersibility of the plate-like inorganic filler was x. Table 1 shows the oxygen barrier properties, moisture permeability, and drop test results.
[0066]
[Example 3]
An optically active isomer (d%) having a d = 2.5% and a weight average molecular weight (Mw) of 190,000 polylactic acid of 95% by weight, and an olefinic wax on a glittering platy mica whose surface is treated with titanium dioxide. A plate-like inorganic material having an average aspect ratio of 200 and an average thickness of 0.6 μm impregnated with 10% by weight relative to mica was dry-blended with 5% by weight. This resin composition was molded into a sheet using an extrusion molding machine. Next, a cup was molded using a thermoform molding machine. The dispersibility of the plate-like inorganic filler was good.
[0067]
[Example 4]
A glittering plate having an average aspect ratio of 200 and an average thickness of 0.6 μm obtained by treating 95% by weight of polylactic acid having an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000 with titanium dioxide. 5% by weight of dry mica was dry blended. This resin composition was molded into a film using an extrusion molding machine. The dispersibility of the plate-like inorganic material was Δ. The moisture permeability coefficient (P) is shown in Table-2.
[0068]
[Example 5]
A glittering plate having an average aspect ratio of 200 and an average thickness of 0.6 μm obtained by treating 95% by weight of polylactic acid having an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000 with titanium dioxide. A plate-like inorganic material impregnated with olefinic wax in an amount of 10% by weight with respect to the glossy plate-like mica was dry-blended with 5% by weight. This resin composition was molded into a film using an extrusion molding machine. The dispersibility of the plate-like inorganic material was ○. The moisture permeability coefficient (P) is shown in Table-2.
[0069]
[Example 6]
A glittering plate having an average aspect ratio of 200 and an average thickness of 0.6 μm obtained by treating 50% by weight of polylactic acid having an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000 with titanium dioxide on the surface. A plate-like inorganic material impregnated with 10% by weight of an olefinic wax in the shape of mica as compared with the glittering plate-like mica was dry blended by 50% by weight. This resin composition was molded into a film using an extrusion molding machine. The dispersibility of the plate-like inorganic material was ○. The moisture permeability coefficient (P) is shown in Table-2.
[0070]
[Example 7]
A resin composition comprising 85% by weight of polylactic acid having an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000 and 10% by weight of a second barrier material ethylene vinyl alcohol copolymer resin. 5 wt. Of a plate-like inorganic material obtained by impregnating a surface of titanium dioxide with an average aspect ratio of 200 and an average thickness of 0.6 μm, impregnated with 10 wt% of an olefinic wax, with respect to the bright plate-like mica material. % Dry blended. This resin composition was molded into a film using an extrusion molding machine. The dispersibility of the plate-like inorganic material was ○. The moisture permeability coefficient (P) is shown in Table-2.
[0071]
[Comparative Example 3]
Dry blend of 95% polylactic acid with an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000, and 5% by weight of plate-like mica with an average aspect ratio of 200 and an average thickness of 0.6 μm did. This resin composition was molded into a film using an extrusion molding machine. The dispersibility of the plate-like inorganic material was x. The moisture permeability coefficient (P) is shown in Table-2.
[0072]
[Comparative Example 4]
A resin composition comprising 85% by weight of polylactic acid having an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000 and 10% by weight of a second barrier material ethylene vinyl alcohol copolymer resin. 5% by weight of a plate-like mica having an average aspect ratio of 200 and an average thickness of 0.6 μm was dry blended. This resin composition was molded into a film using an extrusion molding machine. The dispersibility of the plate-like inorganic material was x. The moisture permeability coefficient (P) is shown in Table-2.
[0073]
[Comparative Example 5]
A resin composition comprising 85% by weight of polylactic acid having an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000 and 10% by weight of a second barrier material ethylene vinyl alcohol copolymer resin. 5% by weight of a plate-like inorganic material in which 50% by weight of an olefinic wax is contained in a bright plate-like mica having an average aspect ratio of 200 and an average thickness of 0.6 μm, the surface of which is treated with titanium dioxide, as compared to the bright plate-like mica. Dry blended. This resin composition was molded into a film using an extrusion molding machine. In this case, the film was separated by a wax separation layer and was totally non-uniformly dispersed. For this reason, under the comparative example conditions, the dispersibility of the plate-like inorganic material was set to x. The moisture permeability coefficient (P) is shown in Table-2.
[0074]
[Example 8]
Using a co-injection molding machine, in the first shot, after injection molding into a preform using polylactic acid with an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000, On the outer side of the reforming layer, an average thickness of 0.6 μm with an average aspect ratio of 200 is obtained by treating the surface with titanium dioxide with respect to polylactic acid having an optically active isomer (d%) of d = 2.5% and a weight average molecular weight (Mw) of 190,000. A resin composition obtained by dry blending 40% by weight of a plate-like inorganic material impregnated with 10% by weight of a polyolefin-based wax into the bright plate-like mica as compared with the glittering plate-like mica was injection molded. Next, the preform was heated to 70 ° C. or higher with an infrared heater and then blow-molded into a square bottle at a mold temperature of 90 ° C. In this case, the molded bottle could be molded into a predetermined shape without delamination.
[0075]
[Table 1]

[0076]
[Table 2]

[0077]
【The invention's effect】
  According to the present invention, the biodegradable resinBrightness impregnated with resinous or waxy dispersantBy containing a plate-like filler and a resinous or waxy dispersant, the dispersibility of the plate-like additive in the biodegradable resin can be remarkably improved, and the plate-like shape at the time of molding of this resin composition The orientation of the additive in the plane direction can also be significantly improved. Furthermore, the remarkable gas barrier property improvement was ensured by containing 2nd barrier property resin. The biodegradable resin composition of the present invention isBrightness impregnated with resinous or waxy dispersantDespite containing a plate-like filler, it has excellent moldability, outstanding mechanical strength and impact resistance, and gas barrier properties and appearance characteristics including moisture barrier properties. Can be significantly improved.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the blending amount and moisture permeation amount when a plate-like filler (titanium dioxide-coated flake pigment) is blended with a biodegradable resin (polylactic acid).

Claims (12)

A biodegradable resin composition comprising a biodegradable resin and a glittering platy filler impregnated with a resinous or waxy dispersant .   The plate-like filler is contained in an amount of 2 to 70 parts by weight and the resinous or waxy dispersant is contained in an amount of 0.05 to 20 parts by weight per 100 parts by weight of the biodegradable resin. Biodegradable resin composition.   The biodegradable resin composition according to claim 1 or 2, wherein the biodegradable resin is an aliphatic polyester containing a hydroxyalkanoate unit.   The biodegradable resin composition according to any one of claims 1 to 3, wherein the plate-like filler is an inorganic filler or an organic filler having an aspect ratio of 5 or more. The biodegradable resin composition according to any one of claims 1 to 4 , wherein the plate-like filler is a titanium dioxide-coated flake pigment. The biodegradable resin composition according to any one of claims 1 to 5 , wherein the resinous or waxy dispersant has a melting point or softening point lower than the melting point of the biodegradable resin. The biodegradable resin composition according to any one of claims 1 to 5 , further comprising a gas barrier resin.   The biodegradable resin composition according to claim 2, wherein the gas barrier resin is contained in an amount of 2 to 49 parts by weight per 100 parts by weight of the biodegradable resin. A packaging container formed from the biodegradable resin composition according to any one of claims 1 to 8 . The packaging container according to claim 9 , wherein the plate-like filler in the biodegradable resin composition is oriented in the surface direction of the wall surface constituting the container. The packaging container according to claim 9 or 10 , wherein the resin constituting the vessel wall is biaxially oriented. A multilayer packaging container comprising at least one layer made of the biodegradable resin composition according to any one of claims 1 to 8 .

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