JP2005015742A - Biodegradable polyester-based resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a biodegradable polyester-based resin composition excellent in transparency and hydrolysis resistance and having a high antistatic property even by suppressing the amount of use of a quaternary ammonium salt having a high toxicity. <P>SOLUTION: This resin composition contains 0.05-10.0 wt.% surfactant composition consisting of 90-10 wt.% quaternary ammonium salt having sulfonate as a counter ion and 10-90 wt.% nonionic surfactant, based on the biodegradable polyester-based resin. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４の内の少なくとも一つは炭素数８〜２４の同一もしくは異なった直鎖もしくは分岐鎖のアルキル基、アルケニル基、ヒドロキシアルキル基、アルキルアリール基、又は下記一般式（Ｂ）を示す。
Ｒ_５−Ｙ−Ｒ_６− （Ｂ）
［Ｒ_５は炭素数８〜２４のアルキル基、アルケニル基、ヒドロキシアルキル基、又はアルキルアリール基を示す。Ｒ_６は炭素数１〜５のアルキレン基を示す。Ｙは−Ｃ（＝Ｏ）ＮＨ−、−ＮＨＣ（＝Ｏ）−、−Ｃ（＝Ｏ）Ｏ−、又は−ＯＣ（＝Ｏ）−、−Ｏ−を示す。］
Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４の内の上記で限定したもの以外は炭素数１〜５のアルキル基、炭素数８〜２４のアリールアルキル基、又は−（ＺＯ）_ｍ−Ｈ基（Ｚは炭素数２〜４のアルキレン基、ｍは１〜４０である。）を示す。Ｘ⁻はスルホネート（−ＳＯ_３ ⁻）を有する対イオンを示す。
【００２２】
＜ノニオン界面活性剤群＞
（１）ポリエチレングリコール型ノニオン界面活性剤
（２）多価アルコール型ノニオン界面活性剤
【００２３】
以下本発明を詳細に説明する。
本発明は、上記一般式（Ａ）で表されるスルホネートを対イオンに有する第４級アンモニウム塩９０重量％〜１０重量％と上記特定のノニオン界面活性剤群から選ばれる少なくとも１種類のノニオン界面活性剤１０重量％〜９０重量％からなる界面活性剤組成物を０．０５重量％〜１０．０重量％含有する帯電防止性と透明性に優れた生分解性ポリエステル系樹脂組成物に関する。
【００２４】
以下、本発明のスルホネートを対イオンに有する第４級アンモニウム塩について説明する。
上記一般式（Ａ）で表されるスルホネートを対イオンに有する第４級アンモニウム塩において、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４の内の少なくとも一つは炭素数が１０〜２４で、特に炭素数１２〜２２の直鎖もしくは分岐鎖のアルキル基、アルケニル基、ヒドロキシアルキル、又は上記一般式（Ｂ）が好ましい。Ｒ_５としては炭素数１０〜２４が好ましく、更に好ましくは炭素数１２〜２２のアルキル基、アルケニル基がよい。Ｒ_６としては炭素数１〜４のアルキレン基が好ましく、メチレン基、エチレン基、プロピレン基が更に好ましい。Ｙとしては−Ｃ（＝Ｏ）ＮＨ−、−Ｃ（＝Ｏ）Ｏ−、又は−ＯＣ（＝Ｏ）−が好ましく、−Ｃ（＝Ｏ）ＮＨ−が更に好ましい。他は炭素数１〜４のアルキル基、又は−（ＣＨ_２ＣＨ_２Ｏ）ｍ−Ｈ基が好ましく、更に好ましくはメチル基、エチル基、プロピル基、−（ＣＨ_２ＣＨ_２Ｏ）_２〜１０−Ｈ基がよい。
【００２５】
対イオンＸ⁻としては炭素数１〜２０のアルキル基、アルケニル基、アルキルアリール基を有するスルホネートが好ましいが、更に好ましくはメチルスルホネート、エチルスルホネート、ラウリルスルホネート、ラウリルベンゼンスルホネートがよい。
【００２６】
本発明のスルホネートを対イオンに有する第４級アンモニウム塩の好ましい具体例として、以下の化合物が挙げられるが、これに限定されるものではない。
【００２７】
第４級アンモニウム塩（１）
【化３】

第４級アンモニウム塩（２）
【化４】

第４級アンモニウム塩（３）
【化５】

【００２８】
本発明のスルホネートを対イオンに有する第４級アンモニウム塩の合成は公知の方法で得ることができる。アミンをメタンスルホン酸、メタンスルホン酸メチル、ドデシルベンゼンスルホン酸、メタンスルホン酸ベンジル等の４級化剤にて合成する方法、又はアミンをメチルクロライド、メチルブロマイド、メチル硫酸、ジメチル硫酸、ジエチル硫酸等の４級化剤にて第４級アンモニウム塩にした後、ラウリルスルホン酸ナトリウム、ラウリルベンジルスルホン酸ナトリウム等のスルホン酸塩系アニオン界面活性剤との塩交換をする方法等が挙げられるが、特に限定するものではない。
更に具体的には、例えば第４級アンモニウム塩（１）の合成物に関しては、第３級アミンであるラウリルジメチルアミンをメタンスルホン酸メチルで４級化することで目的の第４級アンモニウム塩を得ることができる。又は第４級アンモニウム塩（２）の合成物に関してはＮ，Ｎ−ポリオキシエチレン（５）−Ｎ−ステアリルアミンをメチルクロライド等の４級化剤で第４級アンモニウム塩にし、得られたＮ，Ｎ−ポリオキシエチレン（５）−Ｎ−ステアリル−Ｎ−メチルアンモニウムクロライドをラウリルスルホン酸ナトリウムとの塩交換で目的のスルホネートの第４級アンモニウム塩にすることができる。
【００２９】
本発明のノニオン界面活性剤とは、下記ノニオン界面活性剤群（１）及び／又は（２）から選ばれる少なくとも１種類のノニオン界面活性剤を示す。
（１）ポリエチレングリコール型ノニオン界面活性剤
（２）多価アルコール型ノニオン界面活性剤
【００３０】
ポリエチレングリコール型ノニオン界面活性剤とは高級アルコール、脂肪酸などの界面活性剤の疎水基原料にエチレンオキサイドを付加して得られるノニオン界面活性剤である。疎水基原料のアルキル基に特に限定はないが、炭素数１２〜１８のアルキル基又はアルケニル基が好ましく、エチレンオキサイド付加モル数は結合している疎水基にもよるが２〜４０が好ましく、更に好ましくは５〜２０がよい。具体的な系統しては、高級アルコールエチレンオキサイド付加物系、アルキルフェノールエチレンオキサイド付加物系、脂肪酸エチレンオキサイド系、多価アルコール脂肪酸エステルエチレンオキサイド付加物系、ポリプロピレングリコールエチレンオキサイド系等が挙げられ、更に具体的には、ポリオキシエチレンラウリルエーテル、ポリオキシエチレンステアリルエーテル、ポリオキシエチレンオレイルエーテル、ポリオキシエチレンオクチルフェノール、ポリエチレングリコールモノラウレート、ポリエチレングリコールモノステアレート、ポリエチレングリコールモノオレート、ポリオキシエチレンソルビタンモノラウレート、ポリオキシエチレンソルビタンモノステアレート、ポリオキシエチレンソルビタンモノオレート等が挙げられるが、これらに限定されるものではない。上記のポリエチレングリコール型ノニオン界面活性剤が上記の第４級アンモニウム塩と加温により混合するものであれば単独、併用は問わない。
【００３１】
多価アルコール型ノニオン界面活性剤とは、グリセリン、ポリグリセリン、ソルビタン等の親水基原料である多価アルコールに疎水基原料である脂肪酸を反応させて得られるノニオン界面活性剤である。反応させる脂肪酸の炭素数は１２〜１８のアルキル基又はアルケニル基が好ましく、モノエステル型が好適である。ポリグリセリンはジ、トリ、テトラの中でもジグリセリンが好ましい。具体的な系統としては、グリセリン脂肪酸エステル系、ポリグリセリン脂肪酸エステル系、ペンタエリスリトール脂肪酸エステル系、ソルビトール脂肪酸エステル系、ソルビタン脂肪酸エステル系、ショ糖脂肪酸エステル系が挙げられ、更に具体的には、グリセリンモノラウレート、グリセリンモノステアレート、グリセリンモノオレート、ジグリセリンモノラウレート、ジグリセリンモノステアレート、ジグリセリンモノオレート、ペンタエリスリトールモノラウレート、ペンタエリスリトールモノステアレート、ペンタエリスリトールモノオレート、ソルビタンモノラウレート、ソルビタンモノステアート、ソルビタンモノオレート等が挙げらるが、これらに限定されるものではない。上記の多価アルコール型ノニオン界面活性剤が上記の第４級アンモニウム塩と加温により混合するものであれば単独、併用は問わない。
【００３２】
本発明において、上記の第４級アンモニウム塩と上記のノニオン界面活性剤との配合比は、上記の第４級アンモニウム塩９０重量％〜１０重量％と上記のノニオン界面活性剤１０重量％〜９０重量％とからなることが必要であり、更には上記の第４級アンモニウム塩９０〜５０重量％と上記のノニオン界面活性剤１０〜５０重量％となることが好ましい。第４級アンモニウム塩が９０重量％を超えた場合、毒性の高い第４級アンモニウム塩の低減という発明の趣旨に反し、１０重量％を下回った場合には帯電防止効果の弱いノニオン界面活性剤が大半を占める為やはり好ましくない。
【００３３】
生分解性ポリエステル系樹脂に対する本発明の界面活性剤組成物の含有量は０．０５重量％〜１０．０重量％であるが、より好ましくは０．１重量％〜５．０重量％であり、更に好ましくは０．５重量％〜２．０重量％である。本発明に係わる界面活性剤組成物の含有量に比例して帯電防止性は向上するが、１０．０重量％以上を超えても帯電防止性に大きな向上はなく、むしろ過剰添加によるコスト高、及び樹脂の機械的物性に影響をもたらすことになる。
【００３４】
本発明の界面活性剤組成物は、生分解性ポリエステル系樹脂の水分による加水分解を防止する為に、予め乾燥させることが望ましい。好ましくは界面活性剤組成物内の水分量が１．０重量％以下である。
【００３５】
以下、本発明の生分解性ポリエステル系樹脂について説明する。
本発明に用いられる生分解性ポリエステル系樹脂は、例えばポリ乳酸（Ｌ−乳酸又はＤ−乳酸、もしくはこれらの混合物を重合することにより得られるポリ乳酸、単量体単位がＬ−乳酸のみからなるポリ乳酸、同じくＤ−乳酸のみからなるポリ乳酸の混合物）、ポリブチレンサクシネート、ポリブチレンサクシネートアジペート、ポリブチレンサクシネートテレフタレート、ポリブチレンサクシネートカーボネート、ポリブチレンアジペートテレフタレート、ポリエチレンサクシネート、ポリエチレンサクシネートアジペート、ポリカプロラクトン、ポリグリコール酸系樹脂等が挙げられる。これらの単量体単位は化学修飾されていてもよく、異種の単量体単位の共重合物であってもよい。
また単量体単位としてグリコール酸、３−ヒドロキシ酪酸等のヒドロキシカルボン酸、コハク酸、アジピン酸等の多価カルボン酸、酢酸セルロース、エチルセルロース等の多糖類、エチレングリコール、ジエチレングリコール等の多価アルコールのうち１種又は２種以上と上記樹脂の単量体単位との混合物との共重合体であってもよい。
更に本発明の目的を阻害しない範囲で、例えばデンプン系、キトサン系、ポリビニルアルコール系などの樹脂や石油系樹脂を配合しても構わない。
【００３６】
本発明に用いる生分解性ポリエステル系樹脂の製造方法は、公知の方法が用いられる。ポリ乳酸系樹脂の場合、乳酸を直接脱水縮重合する方法、或いは乳酸の環状２量体であるラクチドを開環重合する方法等、公知の方法が用いられるが、これに限定されるものではない。
【００３７】
本発明に用いる生分解性ポリエステル系樹脂の分子量は、フィルム、シート、成型品等の成型加工条件において最適な分子量であれば、特に限定されるものではない。
【００３８】
本発明の目的を損なわない範囲で、必要により本発明以外の公知のアニオン界面活性剤、カチオン界面活性剤、ノニオン界面活性剤、両性界面活性剤を単独或いは２種以上併用させても良い。
【００３９】
本発明の目的を損なわない範囲で可塑剤、酸化防止剤、滑剤、着色剤、紫外線吸収剤、光安定剤、顔料、無機フィラー等の各種添加剤、改質剤、充填剤を付加成分として添加することができる。
【００４０】
生分解性ポリエステル系樹脂を加熱加工するにあたり、水分による加水分解を抑制する為にポリエステル系樹脂の十分な乾燥が必要である。従って予め使用する樹脂は窒素雰囲気下の８０℃にて１０時間の乾燥を行うことが好ましい。
【００４１】
本発明の界面活性剤組成物の添加方法は、公知の方法で行われる。すなわち、高濃度のマスターバッチを別に作製し、これをフィルム及びシート等の成型品を得るまでの任意の工程で混合しても良いし、生分解性ポリエステル系樹脂パウダーとあらかじめ混合しても良い。
【００４２】
本発明における生分解性ポリエステル系樹脂は押し出し機及びＴダイ、インフレーション等によりフィルム、シート等に成型可能である。押し出し時の温度は樹脂の溶融粘度を考慮すると１８０〜２５０℃が好ましい。
【００４３】
この効果発現に関しては、本発明のスルホネートを対イオンに有する第４級アンモニウム塩が、他の対イオンを有する第４級アンモニウム塩と比較して高い耐熱性を有していることから熱履歴による分解を抑制していること、及び特定のノニオン界面活性剤との混合により、生分解性ポリエステル系樹脂に対して適切な相溶性が得られることが、生分解性ポリエステル系樹脂組成物の帯電防止性の相乗効果、透明性及び分子量の維持に大きく寄与しているものと推定しており、これが本発明の根幹を成すものである。
【００４４】
更に、本発明に係わる界面活性剤組成物を配合させることにより、生分解性ポリエステル系樹脂組成物に防曇性を付与することもできる。
【００４５】
次に、実施例により本発明を具体的に説明するが、本発明は実施例に限定されるものではない。実施例及び比較例で使用したノニオン界面活性剤は下記のとおりである。又対イオンがクロライド（Ｃｌ⁻）であるカチオン界面活性剤を比較第４級アンモニウム塩として実施例と比較した。
【００４６】
（１）ポリエチレングリコール型ノニオン界面活性剤
（１）−ａ；ポリオキシエチレンオレイルエーテル（東邦化学工業（株）製 ペグノールＯ−１６Ａ）
（１）−ｂ；ポリエチレングリコールモノステアレート（東邦化学工業（株）製ペグノール１４−Ｓ）
（１）−ｃ；ポリオキシエチレンソルビタンモノステアレート（東邦化学工業（株）製 ソルボンＴ−６０）
【００４７】
（２）多価アルコール型ノニオン界面活性剤
（２）−ａ；グリセリンモノステアレート（東邦化学工業（株）製 アンステックスＭＧ−１００）
（２）−ｂ；ジグリセリンモノラウレート（理研ビタミン（株）製 リケマールＬ−７１−Ｄ）
（２）−ｃ；ソルビタンモノラウレート（東邦化学工業（株）製 ソルボンＳ−６０）
【００４８】
比較第４級アンモニウム塩
【化６】

【００４９】
【実施例】
ポリ乳酸樹脂（レイシアＨ−１００：三井化学（株）製）に対して本発明の第４級アンモニウム塩（１）〜（３）、ノニオン界面活性剤（１）−ａ〜ｃ及び（２）−ａ〜ｃ、及び比較第４級アンモニウム塩を表１及び表２に示した配合比と含有量で添加し、ラボプラストミルとローラミキサー（（株）東洋精機製作所製）にて２００℃で溶解混合した樹脂をプレス機にて厚さ２ｍｍ、縦１００ｍｍ、横１００ｍｍのシート状に成型した。このシートを温度２３℃、相対湿度５０％の恒温恒湿条件下に１４日間放置した後、帯電防止性、透明性及び分子量保持率を評価し、結果を表１及び表２に示す。
【００５０】
＜評価方法＞
シートの性能評価は、具体的に下記の方法によって実施した。
（１）帯電防止性
ＪＩＳ−Ｋ−６９１１に準じ、成型シートの表面固有抵抗値（（株）川口電気製作所製 超絶縁計 Ｐ−６１６）を測定した。数値が小さい程、帯電防止性が優れていることを示す。Ｌｏｇ（表面固有抵抗値Ω／□）は１３以下が目標である。
【００５１】
（２）透明性
ＨＡＺＥ測定装置（東京電色（株）製 ＨＡＺＥＭＥＴＥＲ ＴＣ−ＨＩＩＩＤＰＫ）にて成型シートのＨＡＺＥ値を測定し、界面活性剤無添加シートとの差ΔＨＡＺＥで評価した。ΔＨＡＺＥが小さい程、界面活性剤無添加シートに近い透明性を示す。ΔＨＡＺＥは１０以下が目標である。
【００５２】
（３）分子量保持率
東ソー（株）製クロマトカラム ＴＳＫｇｅｌＧＭＨ_ＸＬ（×２本）を（株）島津製作所製クロマトグラフィーＳＣＬ−１０Ａｖｐに装着し、溶離液クロロホルム、流速１ｍｌ／ｍｉｎ．、カラム温度４０℃、サンプル濃度０．５ｗｔ％、サンプル注入量４０μｌ、検出器ＲＩの条件で測定を行い、ポリスチレン換算で作製したシートの重量平均分子量を算出した。使用した標準ポリスチレンの重量平均分子量は、１０９００００、７０６０００、３５５０００、１９００００、９６４００、３７９００、１９６００、１０２００、５５７０、２６３０、８７０、５００である。
【００５３】
分子量保持率（％）は、［（界面活性剤添加シートの重量平均分子量）／（界面活性剤無添加シートの重量平均分子量）］×１００で算出した。分子量保持率は８０％以上が目標である。
【００５４】
【表１】

【００５５】
【表２】

【００５６】
【発明の効果】
表１の実施例１〜２６の結果に示されるように、本発明のスルホネートを対イオンに有する第４級アンモニウム塩９０重量％〜１０重量％と特定のノニオン界面活性剤群から選ばれる少なくとも１種類のノニオン界面活性剤１０重量％〜９０重量％からなる界面活性剤組成物を０．０５重量％〜１０．０重量％含有する生分解性ポリエステル系樹脂は、分子量の著しい低下もなく透明性があり、毒性の高い第４級アンモニウム塩の使用量を低減してもなお且つ優れた帯電防止性を発揮することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention is a biodegradable polyester-based resin composition having excellent antistatic properties while maintaining transparency and molecular weight, in particular, a biodegradable resin, and is a renewable resource because it is made from plants. The present invention relates to a certain polylactic acid resin composition.
[0002]
[Prior art]
Plastics such as polypropylene, polyethylene, and polyvinyl chloride, which are made from petroleum and other fossil resources, are transformed into food packaging films, electrical appliances, industrial materials, etc., and are indispensable for our lives. . However, since such plastics are not biodegradable, they remain semipermanent in nature after they are no longer needed, which has a major impact on the ecosystem and leads to environmental destruction in various ways. This is a well-known fact.
[0003]
Under such circumstances, biodegradable polyester resins are attracting attention. Among them, plants that are not biodegradable and are trying to convert from plastics derived from fossil resources It is a biodegradable resin that is used as a raw material, that is, derived from plants. Of particular interest in recent years is the polylactic acid-based resin whose production volume is dramatically increasing. The factors that have attracted the attention of polylactic acid-based resins are various factors that use fossil resources as raw materials in the context of a material recycling system that conserves limited fossil resources and thoroughly recycles them. While plastics are greatly out of the circulation system, it is possible to construct a material circulation system that recycles sugar obtained from plants such as corn or potato or polylactic acid synthesized from lactic acid obtained by fermenting them. It is because it is expected as a thing.
[0004]
The raw material of polylactic acid resin is synthesized from sugars obtained from cereals such as corn or potato, which are renewable resources, or lactic acid obtained by fermenting them. After being easily hydrolyzed and decomposed by microorganisms, it finally becomes water and carbon dioxide.
[0005]
It is also known that resin molded products such as films and sheets made of biodegradable polyester resins such as polylactic acid resins exhibit the same performance as conventional plastics. Among these, polylactic acid-based resins have very high transparency, and can be used for packaging applications that place importance on transparency. In addition, the water vapor permeability is higher than that of conventional OPP or OPS films, and there is an expectation that these films can be substituted.
[0006]
However, biodegradable polyester resins that have several advantages and can be used in molded products such as films and sheets are very charged because they have electrical insulating properties unique to resins as well as general resins. There are many problems due to electrification, such as ink repelling at the time of printing, scattering when packing the contents, or dust adhering to the product and deteriorating the appearance.
[0007]
As a means for solving charging, Patent Document 1 discloses that an antistatic property is imparted by applying an aqueous coating liquid containing a surfactant to at least one surface of an aliphatic polyester film. Alternatively, Patent Document 2 shows that antistatic properties can be imparted by applying a blend solution of a specific anionic surfactant or a specific nonionic surfactant to a polylactic acid biaxially stretched film.
[0008]
However, in general, the coating method increases the number of coating steps after resin molding, resulting in an increase in cost, and there are problems such as slipperiness, poor transparency, or lack of sustainability of the antistatic performance specific to the coating method.
[0009]
In addition to the method of applying a surfactant to the surface of a molded product such as a film, there is a kneading method in which a surfactant is added to a resin in advance.
[0010]
In the kneading method, since the surfactant is pre-kneaded into the resin, the surfactant will exude to the surface of the molded product after molding (bleed out) and the performance will be manifested, and the surfactant on the surface will be wiped off. However, when the surfactant inside the resin further bleeds out, the effect is restored, and there is an advantage of having a certain degree of sustainability. In this way, the kneading method expresses performance by bleeding out the surfactant from the resin, but the degree of this bleed out depends on the crystallinity of the resin such as crystallinity and crystal orientation, and the resin. It is said that it largely depends on the compatibility with the surfactant.
[0011]
Furthermore, the compatibility of resin crystallinity and antistatic properties has a great influence on the transparency of the resin, and the addition of an inappropriate surfactant is a biodegradable polyester such as a polylactic acid resin characterized by transparency. Reduces the transparency of the resin.
[0012]
Patent Document 3 discloses that a polylactic acid resin contains a polyhydric alcohol and a fatty acid ester thereof to provide an antistatic film and sheet. Alternatively, Patent Document 4 discloses that polylactic acid contains a nonionic surfactant made of glycerin fatty acid ester to impart antistatic properties. Furthermore, Patent Document 5 shows that an antistatic property is imparted by incorporating a nonionic surfactant containing a glycerin fatty acid ester into a caprolactone-based resin that is a biodegradable resin.
[0013]
As described above, many studies have been made on the kneading method of the nonionic surfactant to the biodegradable resin. However, in reality, the crystallinity unique to the biodegradable polyester resin and the compatibility between the resin and the surfactant are considered. Due to the balance, a sufficiently satisfactory antistatic property is not obtained with the nonionic surfactant.
[0014]
While the kneading method requires antistatic properties, the kneading method requires that the surfactant itself can withstand a high kneading temperature of 180 to 250 ° C. Nonionic surfactants have heat resistance, but as described above, antistatic properties do not reach satisfactory performance. On the other hand, cationic surfactants represented by quaternary ammonium salts, which are generally antistatic, as specified in the Examples of Patent Document 3, have very low heat resistance, especially in biodegradable polyesters. On the other hand, the biodegradable polyester resin is easily hydrolyzed by amines or acids generated by the decomposition of the quaternary ammonium salt due to the thermal history during the resin processing, causing a decrease in molecular weight. The decrease in molecular weight greatly affects various physical properties such as the strength of the molded product.
[0015]
Furthermore, the cationic surfactant has a high skin irritation and toxicity when compared with other types of surfactants, so the content of the cationic surfactant has to be limited with respect to resins for food use.
[0016]
Therefore, these conventional techniques do not necessarily provide the performance required to satisfy all of the antistatic properties, maintenance of molecular weight, appearance such as transparency required for biodegradable polyester resin compositions, and safety for the human body. It could not be said that further improvement was required.
[0017]
[Patent Document 1]
JP-A-10-86307 (page 1-14)
[Patent Document 2]
Japanese Patent Laid-Open No. 14-12687 (page 1-6)
[Patent Document 3]
Japanese Patent Laid-Open No. 9-221587 (page 1-9)
[Patent Document 4]
JP 10-36650 A (page 1-14)
[Patent Document 5]
Japanese Patent Laid-Open No. 14-60603 (page 1-5)
[0018]
[Problems to be solved by the invention]
An object of the present invention is to provide a biodegradable polyester resin composition capable of exhibiting excellent antistatic properties while maintaining transparency and molecular weight even under a kneading method under such circumstances.
[0019]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventors include a quaternary ammonium salt having a sulfonate as a counter ion in a biodegradable polyester resin such as a polylactic acid resin in the biodegradable polyester resin. As a result, it was found that a biodegradable polyester resin composition excellent in antistatic property while maintaining transparency and molecular weight was obtained.
[0020]
Furthermore, by adding a nonionic surfactant to the biodegradable polyester resin in addition to the quaternary ammonium salt having a sulfonate as a counter ion, the antistatic property is superior to the sum of the effects when each is used alone. Therefore, it was found that the amount of quaternary ammonium salt, which is generally highly toxic, can be reduced, and the present invention has been completed.
[0021]
In particular, when a compound represented by the following general formula (A) is used as a quaternary ammonium salt having a sulfonate as a counter ion, higher heat resistance can be obtained as compared with a quaternary ammonium salt having another counter ion. Since it has, the decomposition | disassembly by a heat history is suppressed and the molecular weight of biodegradable polyester-type resin does not fall.
[Chemical 2]

At least one of R ₁ , R ₂ , R ₃ and R ₄ is the same or different linear or branched alkyl group, alkenyl group, hydroxyalkyl group, alkylaryl group having 8 to 24 carbon atoms, or A general formula (B) is shown.
R ₅ -YR _6- (B)
[R ₅ represents an alkyl group having 8 to 24 carbon atoms, an alkenyl group, a hydroxyalkyl group, or an alkylaryl group. R ₆ represents an alkylene group having 1 to 5 carbon atoms. Y represents -C (= O) NH-, -NHC (= O)-, -C (= O) O-, or -OC (= O)-, -O-. ]
R ₁ , R ₂ , R ₃ and R ₄ other than those limited above, an alkyl group having 1 to 5 carbon atoms, an arylalkyl group having 8 to 24 carbon atoms, or a — (ZO) _m —H group ( Z is an alkylene group having 2 to 4 carbon atoms, and m is 1 to 40). X ⁻ represents a counter ion having sulfonate (—SO ₃ ⁻ ).
[0022]
<Nonionic surfactant group>
(1) Polyethylene glycol type nonionic surfactant (2) Polyhydric alcohol type nonionic surfactant
The present invention will be described in detail below.
The present invention relates to at least one nonionic interface selected from 90% by weight to 10% by weight of a quaternary ammonium salt having a sulfonate represented by the above general formula (A) as a counter ion and the specific nonionic surfactant group. The present invention relates to a biodegradable polyester resin composition having excellent antistatic properties and transparency, containing 0.05 wt% to 10.0 wt% of a surfactant composition comprising 10 wt% to 90 wt% of an active agent.
[0024]
Hereinafter, the quaternary ammonium salt having the sulfonate of the present invention as a counter ion will be described.
In the quaternary ammonium salt having the sulfonate represented by the general formula (A) as a counter ion, at least one of R ₁ , R ₂ , R ₃ and R ₄ has 10 to 24 carbon atoms, particularly A linear or branched alkyl group having 12 to 22 carbon atoms, an alkenyl group, a hydroxyalkyl, or the general formula (B) is preferable. R ₅ preferably has 10 to 24 carbon atoms, more preferably an alkyl group or alkenyl group having 12 to 22 carbon atoms. R ₆ is preferably an alkylene group having 1 to 4 carbon atoms, more preferably a methylene group, an ethylene group or a propylene group. Y is preferably —C (═O) NH—, —C (═O) O—, or —OC (═O) —, and more preferably —C (═O) NH—. Others are preferably an alkyl group having 1 to 4 carbon atoms or a — (CH ₂ CH ₂ O) m—H group, more preferably a methyl group, an ethyl group, a propyl group, — (CH ₂ CH ₂ O) _{2 to 10.} The -H group is preferred.
[0025]
Counterion X ^- include the alkyl group having 1 to 20 carbon atoms, an alkenyl group, but-sulfonates having an alkyl aryl group, more preferably methyl sulfonate, ethyl sulfonate, lauryl sulfonate, good lauryl benzenesulfonate.
[0026]
Preferable specific examples of the quaternary ammonium salt having the sulfonate of the present invention as a counter ion include, but are not limited to, the following compounds.
[0027]
Quaternary ammonium salt (1)
[Chemical 3]

Quaternary ammonium salt (2)
[Formula 4]

Quaternary ammonium salt (3)
[Chemical formula 5]

[0028]
The synthesis of the quaternary ammonium salt having the sulfonate of the present invention as a counter ion can be obtained by a known method. A method of synthesizing an amine with a quaternizing agent such as methane sulfonic acid, methyl methane sulfonate, dodecylbenzene sulfonic acid, benzyl methane sulfonate, or an amine with methyl chloride, methyl bromide, methyl sulfuric acid, dimethyl sulfuric acid, diethyl sulfuric acid, etc. The quaternary ammonium salt is used to form a quaternary ammonium salt, and then a salt exchange with a sulfonate anionic surfactant such as sodium lauryl sulfonate or sodium lauryl benzyl sulfonate is exemplified. It is not limited.
More specifically, for example, regarding the synthesized product of the quaternary ammonium salt (1), the quaternary ammonium salt lauryldimethylamine is quaternized with methyl methanesulfonate to obtain the desired quaternary ammonium salt. Obtainable. Alternatively, for the synthesized quaternary ammonium salt (2), N, N-polyoxyethylene (5) -N-stearylamine is converted to a quaternary ammonium salt with a quaternizing agent such as methyl chloride, and the resulting N , N-polyoxyethylene (5) -N-stearyl-N-methylammonium chloride can be converted to the quaternary ammonium salt of the desired sulfonate by salt exchange with sodium lauryl sulfonate.
[0029]
The nonionic surfactant of the present invention refers to at least one nonionic surfactant selected from the following nonionic surfactant group (1) and / or (2).
(1) Polyethylene glycol type nonionic surfactant (2) Polyhydric alcohol type nonionic surfactant
The polyethylene glycol type nonionic surfactant is a nonionic surfactant obtained by adding ethylene oxide to a hydrophobic group raw material of a surfactant such as higher alcohol and fatty acid. The alkyl group of the hydrophobic group raw material is not particularly limited, but is preferably an alkyl group or alkenyl group having 12 to 18 carbon atoms, and the number of moles of ethylene oxide added is preferably 2 to 40 although it depends on the hydrophobic group to which it is bonded. Preferably 5-20 is good. Specific systems include higher alcohol ethylene oxide adduct system, alkylphenol ethylene oxide adduct system, fatty acid ethylene oxide system, polyhydric alcohol fatty acid ester ethylene oxide adduct system, polypropylene glycol ethylene oxide system, etc. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate, polyoxyethylene sorbitan mono Examples include laurate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, etc. It is, but not limited thereto. As long as the polyethylene glycol type nonionic surfactant is mixed with the quaternary ammonium salt by heating, it may be used alone or in combination.
[0031]
The polyhydric alcohol type nonionic surfactant is a nonionic surfactant obtained by reacting a polyhydric alcohol that is a hydrophilic group raw material such as glycerin, polyglycerin, or sorbitan with a fatty acid that is a hydrophobic group raw material. The fatty acid to be reacted is preferably an alkyl group or alkenyl group having 12 to 18 carbon atoms, and is preferably a monoester type. Polyglycerin is preferably diglycerin among di, tri, and tetra. Specific systems include glycerin fatty acid ester, polyglycerin fatty acid ester, pentaerythritol fatty acid ester, sorbitol fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, and more specifically glycerin. Monolaurate, glycerol monostearate, glycerol monooleate, diglycerol monolaurate, diglycerol monostearate, diglycerol monooleate, pentaerythritol monolaurate, pentaerythritol monostearate, pentaerythritol monooleate, sorbitan monolaurate Examples thereof include, but are not limited to, rate, sorbitan monostearate, and sorbitan monooleate. As long as the polyhydric alcohol type nonionic surfactant is mixed with the quaternary ammonium salt by heating, it may be used alone or in combination.
[0032]
In the present invention, the mixing ratio of the quaternary ammonium salt to the nonionic surfactant is 90% to 10% by weight of the quaternary ammonium salt and 10% to 90% of the nonionic surfactant. The quaternary ammonium salt is preferably 90 to 50% by weight and the nonionic surfactant is preferably 10 to 50% by weight. When the amount of the quaternary ammonium salt exceeds 90% by weight, contrary to the spirit of the invention of reducing the highly toxic quaternary ammonium salt, when the amount is less than 10% by weight, a nonionic surfactant having a weak antistatic effect is used. It is also not preferable because it accounts for the majority.
[0033]
The content of the surfactant composition of the present invention with respect to the biodegradable polyester resin is 0.05 wt% to 10.0 wt%, more preferably 0.1 wt% to 5.0 wt%. More preferably, it is 0.5 to 2.0% by weight. Although the antistatic property is improved in proportion to the content of the surfactant composition according to the present invention, there is no significant improvement in the antistatic property even if it exceeds 10.0% by weight or more. In addition, the mechanical properties of the resin are affected.
[0034]
The surfactant composition of the present invention is desirably dried in advance in order to prevent hydrolysis of the biodegradable polyester resin due to moisture. Preferably, the water content in the surfactant composition is 1.0% by weight or less.
[0035]
Hereinafter, the biodegradable polyester resin of the present invention will be described.
The biodegradable polyester resin used in the present invention is, for example, polylactic acid (polylactic acid obtained by polymerizing L-lactic acid or D-lactic acid, or a mixture thereof, and the monomer unit is composed only of L-lactic acid. Polylactic acid, also a mixture of polylactic acid consisting only of D-lactic acid), polybutylene succinate, polybutylene succinate adipate, polybutylene succinate terephthalate, polybutylene succinate carbonate, polybutylene adipate terephthalate, polyethylene succinate, polyethylene succinate Nate adipate, polycaprolactone, polyglycolic acid resin and the like. These monomer units may be chemically modified or may be a copolymer of different monomer units.
In addition, as a monomer unit, a hydroxycarboxylic acid such as glycolic acid or 3-hydroxybutyric acid, a polyvalent carboxylic acid such as succinic acid or adipic acid, a polysaccharide such as cellulose acetate or ethylcellulose, or a polyhydric alcohol such as ethylene glycol or diethylene glycol Of these, a copolymer of one or more kinds and a mixture of monomer units of the resin may be used.
Further, for example, starch-based, chitosan-based, polyvinyl alcohol-based resins and petroleum-based resins may be blended as long as the object of the present invention is not impaired.
[0036]
As a method for producing the biodegradable polyester resin used in the present invention, a known method is used. In the case of a polylactic acid-based resin, a known method such as a method of directly dehydrating condensation polymerization of lactic acid or a method of ring-opening polymerization of lactide which is a cyclic dimer of lactic acid is used, but is not limited thereto. .
[0037]
The molecular weight of the biodegradable polyester resin used in the present invention is not particularly limited as long as it is an optimum molecular weight under molding processing conditions such as a film, a sheet, and a molded product.
[0038]
As long as the object of the present invention is not impaired, known anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants other than the present invention may be used alone or in combination of two or more.
[0039]
Various additives such as plasticizers, antioxidants, lubricants, colorants, ultraviolet absorbers, light stabilizers, pigments, inorganic fillers, modifiers, and fillers are added as additional components within the scope of the present invention. can do.
[0040]
In heat-treating a biodegradable polyester resin, it is necessary to sufficiently dry the polyester resin in order to suppress hydrolysis due to moisture. Therefore, it is preferable that the resin used in advance is dried for 10 hours at 80 ° C. in a nitrogen atmosphere.
[0041]
The method for adding the surfactant composition of the present invention is performed by a known method. That is, a high-concentration master batch is prepared separately, and this may be mixed in an arbitrary process until a molded product such as a film and a sheet is obtained, or may be mixed in advance with a biodegradable polyester resin powder. .
[0042]
The biodegradable polyester resin in the present invention can be molded into a film, a sheet or the like by an extruder, a T-die, inflation or the like. The temperature during extrusion is preferably 180 to 250 ° C. in view of the melt viscosity of the resin.
[0043]
Regarding the manifestation of this effect, the quaternary ammonium salt having the sulfonate of the present invention as a counter ion has higher heat resistance than the quaternary ammonium salt having another counter ion, so that it depends on the thermal history. Antistatic of the biodegradable polyester resin composition that the decomposition is suppressed and that the appropriate compatibility with the biodegradable polyester resin is obtained by mixing with a specific nonionic surfactant. It is presumed that it greatly contributes to the maintenance of the synergistic effect of the sex, transparency and molecular weight, which forms the basis of the present invention.
[0044]
Furthermore, antifogging properties can be imparted to the biodegradable polyester resin composition by incorporating the surfactant composition according to the present invention.
[0045]
EXAMPLES Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to the examples. Nonionic surfactants used in Examples and Comparative Examples are as follows. In addition, a cationic surfactant having a counter ion of chloride (Cl ⁻ ) was compared with the examples as a comparative quaternary ammonium salt.
[0046]
(1) Polyethylene glycol type nonionic surfactant (1) -a; polyoxyethylene oleyl ether (Pegnol O-16A, manufactured by Toho Chemical Industry Co., Ltd.)
(1) -b: Polyethylene glycol monostearate (Pegnol 14-S manufactured by Toho Chemical Co., Ltd.)
(1) -c; polyoxyethylene sorbitan monostearate (Sorbon T-60 manufactured by Toho Chemical Co., Ltd.)
[0047]
(2) Polyhydric alcohol type nonionic surfactant (2) -a; glycerin monostearate (Anstex MG-100 manufactured by Toho Chemical Industry Co., Ltd.)
(2) -b; diglycerin monolaurate (Rikenmar L-71-D, manufactured by Riken Vitamin Co., Ltd.)
(2) -c; sorbitan monolaurate (Sorbon S-60 manufactured by Toho Chemical Industry Co., Ltd.)
[0048]
Comparative quaternary ammonium salt

[0049]
【Example】
Quaternary ammonium salts (1) to (3), nonionic surfactants (1) to ac and (2) of the present invention against polylactic acid resin (Lacia H-100, manufactured by Mitsui Chemicals, Inc.) -A to c, and comparative quaternary ammonium salt were added at the blending ratio and content shown in Tables 1 and 2, and at 200 ° C. using a lab plast mill and a roller mixer (manufactured by Toyo Seiki Seisakusho). The dissolved and mixed resin was molded into a sheet having a thickness of 2 mm, a length of 100 mm, and a width of 100 mm with a press. The sheet was allowed to stand for 14 days under a constant temperature and humidity condition of a temperature of 23 ° C. and a relative humidity of 50%. Then, the antistatic property, transparency and molecular weight retention were evaluated, and the results are shown in Tables 1 and 2.
[0050]
<Evaluation method>
The sheet performance was specifically evaluated by the following method.
(1) Antistatic property According to JIS-K-6911, the surface specific resistance value (super insulation meter P-616, manufactured by Kawaguchi Electric Co., Ltd.) of the molded sheet was measured. The smaller the value, the better the antistatic property. The target of Log (surface resistivity Ω / □) is 13 or less.
[0051]
(2) The HAZE value of the molded sheet was measured with a transparent HAZE measuring device (HAZEMETER TC-HIIIDPK manufactured by Tokyo Denshoku Co., Ltd.), and evaluated by the difference ΔHAZE from the surfactant-free sheet. The smaller ΔHAZE is, the closer the transparency is to the surfactant-free sheet. The target for ΔHAZE is 10 or less.
[0052]
(3) Molecular Weight Retention Rate Chromatography column TSKgelGMH _XL (× 2) manufactured by Tosoh Corporation was attached to chromatography SCL-10Avp manufactured by Shimadzu Corporation, and the eluent chloroform, flow rate 1 ml / min. The measurement was performed under the conditions of a column temperature of 40 ° C., a sample concentration of 0.5 wt%, a sample injection amount of 40 μl, and a detector RI, and the weight average molecular weight of the sheet prepared in terms of polystyrene was calculated. The weight average molecular weights of the standard polystyrene used are 1090000, 706000, 355000, 190000, 96400, 37900, 19600, 10200, 5570, 2630, 870, 500.
[0053]
The molecular weight retention rate (%) was calculated by [(weight average molecular weight of the surfactant-added sheet) / (weight average molecular weight of the surfactant-free sheet)] × 100. The target molecular weight retention is 80% or more.
[0054]
[Table 1]

[0055]
[Table 2]

[0056]
【The invention's effect】
As shown in the results of Examples 1 to 26 in Table 1, at least one selected from 90 wt% to 10 wt% of a quaternary ammonium salt having the sulfonate of the present invention as a counter ion and a specific nonionic surfactant group. A biodegradable polyester resin containing 0.05% to 10.0% by weight of a surfactant composition comprising 10% to 90% by weight of a nonionic surfactant is transparent without a significant decrease in molecular weight. Even if the amount of highly quaternary ammonium salt used is reduced, excellent antistatic properties can be exhibited.

Claims (6)

90 wt% to 10 wt% of a quaternary ammonium salt having a sulfonate as a counter ion and 10 wt% to 90 wt% of at least one nonionic surfactant selected from the following nonionic surfactant group (1) and / or (2) A biodegradable polyester resin composition comprising 0.05% by weight to 10.0% by weight of a surfactant composition comprising 5% by weight.
<Nonionic surfactant group>
(1) Polyethylene glycol type nonionic surfactant (2) Polyhydric alcohol type nonionic surfactant The biodegradable polyester resin composition according to claim 1, wherein the quaternary ammonium salt having a sulfonate as a counter ion is a compound represented by the following general formula (A).

At least one of R ₁ , R ₂ , R ₃ and R ₄ is the same or different linear or branched alkyl group, alkenyl group, hydroxyalkyl group, alkylaryl group having 8 to 24 carbon atoms, or A general formula (B) is shown.
R ₅ -YR _6- (B)
[R ₅ represents an alkyl group having 8 to 24 carbon atoms, an alkenyl group, a hydroxyalkyl group, or an alkylaryl group. R ₆ represents an alkylene group having 1 to 5 carbon atoms. Y represents —C (═O) NH—, —NHC (═O) —, —C (═O) O—, —OC (═O) —, or —O—. ]
R ₁ , R ₂ , R ₃ and R ₄ other than those limited above, an alkyl group having 1 to 5 carbon atoms, an arylalkyl group having 8 to 24 carbon atoms, or a — (ZO) _m —H group ( Z is an alkylene group having 2 to 4 carbon atoms, and m is 1 to 40). X ^- is sulfonate represents a counter ion having a ^(- - SO _3). The biodegradable polyester resin composition according to claim 1 or 2, which has excellent antistatic properties while maintaining transparency and molecular weight. A surfactant composition comprising 90% to 10% by weight of a quaternary ammonium salt having the sulfonate of claim 1 or 2 as a counter ion and 10% to 90% by weight of a nonionic surfactant is 0.05. A polylactic acid resin composition containing 1 wt% to 10.0 wt%. The polylactic acid-based resin composition according to claim 4, which has excellent antistatic properties while maintaining transparency and molecular weight. A resin molded article such as a film or sheet comprising the biodegradable polyester resin composition according to any one of claims 1 to 3 or the polylactic acid resin composition according to claim 4 or 5.