JP3570782B2 - Aliphatic Ester-Amide Copolymer Resin Porous Fine Particles and Production Method Thereof - Google Patents
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Description
【０００１】
【産業上の利用分野】
本発明は、所定の平均粒子径を有する脂肪族エステル−アミド共重合樹脂多孔微粒子及びその製造方法に関する。
【０００２】
【従来の技術】
脂肪族エステル−アミド共重合樹脂は、脂肪族アミド樹脂の有する強靱さと、脂肪族エステルの有する良好な加工性とを合わせ持ち、さらには脂肪族エステルの有する生分解性をも持ちうる優れた樹脂である（特公昭５６−３８１１５号公報、特公昭５７−２６６８８号公報、特開平６−２０００１６号公報、特開平６−１９２４１７号公報等参照）。
【０００３】
一般的に樹脂の微粒子を成形するには、樹脂が不溶な有機溶媒や水からなる分散媒中で、樹脂を加熱溶解させた状態で攪拌することで溶融樹脂を微粒子状に分散させ、その後冷却して樹脂微粒子を得る方法や、懸濁重合による方法がよく用いられていた。しかしながら、脂肪族エステル−アミド共重合樹脂の場合、分散媒に水を用いると樹脂の加水分解が起こる他、冷却時には粒子同士が合着しやすいため、微粒子を得るのが非常に困難であった。
【０００４】
また、樹脂を溶剤に溶解させて溶液状としたのち、樹脂が不溶でかつ溶剤が可溶な有機溶媒や水からなる分散媒中に混合攪拌することで、樹脂を再析出させると同時に微粒子化する方法もよく用いられるが、脂肪族エステル−アミド共重合樹脂を溶液状態とするには、ギ酸、ヘキサフルオロ−２−プロパノール、ｍ−クレゾール等の、人体に対して非常に有害であったり、オゾン層破壊等の環境破壊性の高い溶剤を用いなければならず、取扱いの容易な良溶剤は知られていない。このように、脂肪族エステル−アミド共重合樹脂の微粒子を加水分解などの劣化なしに、また人体、環境に有害な溶剤を使用せずに製造することのできる、より実際的な方法は知られていない。
【０００５】
【発明が解決しようとする課題】
本発明の課題は、毒性や環境汚染性の強い有機溶媒を使用せずに、簡便に脂肪族エステル−アミド共重合樹脂多孔微粒子を製造することのできる方法、及びその方法によって得られる脂肪族エステル−アミド共重合樹脂多孔微粒子を提供することである。
【０００６】
【課題を解決するための手段】
上記課題に鑑み鋭意研究の結果、本発明者等は、金属塩を含有するメタノール、エタノール等の有機溶剤を用いて脂肪族エステル−アミド共重合樹脂を溶液化し、溶剤が含まれた状態で攪拌しながら所定の溶媒と混合することより、ギ酸、ヘキサフルオロ−２−プロパノール、ｍ−クレゾール等の人体や環境に有害な有機溶剤を使用しなくても、脂肪族エステル−アミド共重合樹脂多孔微粒子が得られることを見出し、本発明を完成した。
【０００７】
即ち、本発明は、平均粒子径が０．５ 〜５０μｍであることを特徴とする脂肪族エステル−アミド共重合樹脂多孔微粒子である。
また、本発明は、水分を含有する又は含有しない有機溶剤に金属塩が溶解している溶解液に、脂肪族エステル−アミド共重合樹脂を溶解又は分散させた樹脂混合溶液と、水又は水溶液とを攪拌しながら混合して、該樹脂混合溶液から有機溶剤と金属塩とを除去し、脂肪族エステル−アミド共重合樹脂を析出させることを特徴とする、脂肪族エステル−アミド共重合樹脂多孔微粒子の製造方法である。
さらに、本発明は、水分を含有する又は含有しない有機溶剤に金属塩が溶解している溶解液に、脂肪族エステル−アミド共重合樹脂を溶解又は分散させた樹脂混合溶液と、脂肪族エステル−アミド共重合樹脂及び該金属塩が不溶又は難溶でかつ該有機溶剤が可溶な溶媒とを攪拌しながら混合して、該樹脂混合溶液から有機溶剤を除去し、脂肪族エステル−アミド共重合樹脂と金属塩との混合物を析出させるとともに多孔化することを特徴とする、脂肪族エステル−アミド共重合樹脂多孔微粒子の製造方法である。
【０００８】
以下、本発明を詳細に説明する。
本発明でいう水溶液とは、脂肪族エステル−アミド共重合樹脂を析出させることができ、かつ金属塩を溶出させることのできる、水を溶媒とした溶液をいい、具体的にはメタノール、エタノール、アセトン等の有機溶剤の水溶液、揮発性の酸及びアルカリの水溶液、界面活性剤等の水溶液などをいう。
【０００９】
また、本発明でいう脂肪族エステル−アミド共重合樹脂多孔微粒子は、脂肪族エステル−アミド共重合樹脂と金属塩との混合物を含むものとする。
本発明の脂肪族エステル−アミド共重合樹脂多孔微粒子の製造方法では、まず、金属塩を含む有機溶剤に、脂肪族エステル−アミド共重合樹脂を溶解又は分散させる。本発明における溶解とは、常温又は有機溶剤の沸点を超えない範囲での加温下において、共重合樹脂が実質的に均一な溶液となることをいい、分散とは、常温又は有機溶剤の沸点を超えない範囲での加温下において、有機溶剤の分離や、金属塩及び共重合樹脂の析出が実質的に生じることなく、共重合樹脂と有機溶剤とが実質的に均一な状態になることをいい、溶解、分散とも一部の樹脂混合溶液のゲル化、あるいは有機溶剤の多少の分離が起こる場合（特に常温下）も含むものとする。
【００１０】
本発明で用いる有機溶剤及び金属塩の組み合わせとしては、脂肪族エステル−アミド共重合樹脂を溶解させることができればいかなる組み合わせであってもよいが、共重合樹脂を実用上有効な溶解又は分散状態とするためには、有機溶剤１００重量部に対して金属塩が１重量部以上溶解するような組み合わせであるのが好ましく、有機溶剤１００重量部に対して金属塩が５重量部以上溶解するような組み合わせであるのが特に好ましい。
【００１１】
有機溶剤としては、連続する炭素鎖中の全炭素数が６以下のアルコール、下記の化学式（１）
【００１２】
【化１】
（式中、Ｒ１ は炭素数１〜４のアルキル基、Ｒ２ は水酸基、炭素数１〜４のアルコキシ基、アミノ基又は酢酸基を表し、ｎは１〜３の整数を表す。）
で示されるグリコールエーテル類、炭素数５以下の有機酸、アルキルスルホキシド及び脂肪族アミドから選ばれる少なくとも１種の化合物を含むものが好ましい。
【００１４】
上記アルコールとしては、メタノール、エタノール、エチレングリコール等が挙げられ、グリコールエーテル類としては、２−メトキシエタノール、２−エトキシエタノール等が挙げられ、有機酸としては酢酸等が挙げられ、アルキルスルホキシドとしては、ジメチルスルホキシド等が挙げられ、脂肪族アミドとしては、ジメチルホルムアミド、Ｎ−メチル−２−ピロリドン等が挙げられ、それらを単独で又は適宜混合して用いることができる。
【００１５】
有機溶剤の沸点は、常温での取扱性や、樹脂から溶剤を除去乾燥する容易性を考慮して、３０〜２５０℃の範囲にあるのが好ましい。特に好ましい有機溶剤は、メタノール、エタノール及びそれらの混合物である。
以上説明した有機溶剤は水分を含有していてもよいし、含有していなくてもよい。水分を含有させるか否か又はその含有量は、樹脂多孔微粒子の使用形態等によって適宜選択すればよい。但し、樹脂の含有量の多い混合溶液を得るには、水分含有量は少ないほうが好ましい。
【００１６】
一方、本発明で使用する金属塩としては、原子番号３８以下の周期表Ｉａ、ＩＩａ、Ｉｂ及びＩＩｂ族から選ばれる金属の、ハロゲン化物、ニトロ化物及びチオシアネート化物が好ましく、それらを単独で又は適宜組み合わせて用いることができる。
具体的には、塩化リチウム、塩化カルシウム、塩化マグネシウム、塩化亜鉛、臭化リチウム、臭化カルシウム、臭化マグネシウム、臭化亜鉛、硝酸カルシウム、硝酸マグネシウム、硝酸亜鉛等が挙げられる。特に、潮解性を有する金属塩、例えば塩化カルシウムを使用する場合には、多孔微粒子中に必要量の該金属塩を残存させることにより、得られる脂肪族エステル−アミド共重合樹脂多孔微粒子は優れた吸湿性を有するものとなる。
【００１７】
有機溶剤に対する金属塩の混合比としては、有機溶剤１００重量部に対して金属塩が１〜４０重量部、特に１〜３０重量部であるのが好ましい。金属塩の混合比が上記範囲より小さい場合には得られる樹脂多孔微粒子の量が少なく、上記範囲より大きい場合には、金属塩の析出が起こりやすく、均一な樹脂混合溶液となりにくい。
【００１８】
本発明における脂肪族エステル−アミド共重合樹脂は、脂肪族エステルと脂肪族アミドとが共重合したものであればいかなるものであってもよいが、重合性、原料の単価等を考慮すると、脂肪族エステル単位が、下記の化学式（２）
−Ｏ−Ｒ３ −ＣＯ− …（２）
（式中、Ｒ３ は炭素数１〜６の直鎖状メチレン基又は該直鎖状メチレンに炭素数１〜３のアルキル基が結合した基を表す。）
で示される構造及び／又は下記の化学式（３）
−Ｏ−Ｒ４ −ＯＣＯ−Ｒ５ −ＣＯ− …（３）
（式中、Ｒ４ は炭素数２〜６の、Ｒ６ は炭素数２〜１０の、それぞれ直鎖状メチレン基又はそれら直鎖状メチレンに炭素数１〜３のアルキル基が結合した基を表す。）
で示される構造からなり、脂肪族アミド単位が、下記の化学式（４）
−ＮＨ−Ｒ６ −ＣＯ− …（４）
（式中、Ｒ６ は炭素数２〜１２の直鎖状メチレン基又は該直鎖状メチレンに炭素数１〜３のアルキル基が結合した基を表す。）
で示される構造及び／又は下記の化学式（５）
−ＮＨ−Ｒ７ −ＮＨＣＯ−Ｒ８ −ＣＯ− …（５）
（式中、Ｒ７ は炭素数２〜６の、Ｒ８ は炭素数２〜１０の、それぞれ直鎖状メチレン基又はそれら直鎖状メチレンに炭素数１〜３のアルキル基が結合した基を表す。）
で示される構造からなり、それらが共重合したものが好ましい。共重合の形態としては、通常の共重合であってもよいし、ブロック共重合、グラフト共重合あるいは交互共重合であってもよい。さらに、本発明における脂肪族エステル−アミド共重合樹脂には、高分子同士を結合し、更に高分子化する目的で添加される少量の分子延長剤、具体的にはジイソシアネート、多塩基酸等に由来する構造を含ませることができる。
【００１９】
脂肪族エステル−アミド共重合樹脂主鎖中のアミド単位の割合は、共重合樹脂の加工性を良好にするためには１０〜８０モル％であるのが好ましく、さらに生分解性を付与するためには１０〜６０モル％であるのが好ましい。
脂肪族エステル−アミド共重合樹脂の重量平均分子量は、５，０００〜５００，０００であるのが好ましい。５，０００以上であれば、樹脂多孔微粒子の物性が良好で実用範囲が広く、５００，０００以下であれば、合成時間を短縮でき、また真空度などの反応条件も緩和できる。
【００２０】
金属塩を含む有機溶剤に対する脂肪族エステル−アミド共重合樹脂の混合比としては、金属塩を含む有機溶剤１００ 重量部に対し、共重合樹脂１〜３０重量部であるのが好ましく、１〜２０重量部であるのがより好ましい。共重合樹脂の混合比がこの範囲より小さい場合には、溶剤と金属塩の除去・回収に多大な時間や手間を要するため実用的でなく、この範囲より大きい場合には、樹脂の溶解が不十分で析出が起こりやすいうえ、混合溶液の粘度も高くなり、微粒子化が難しくなる。
【００２１】
なお、金属塩に結晶水として含まれていた水分は樹脂混合溶液中に残存していてもよいが、その含水量は、脂肪族エステル−アミド共重合樹脂を溶解又は分散する際に樹脂の析出が起こらない範囲で適宜制御すればよい。
脂肪族エステル−アミド共重合樹脂を溶解液に溶解又は分散させる際には、加温するのが好ましい。このように加温することにより、短時間で脂肪族エステル−アミド共重合樹脂を溶解又は分散させることができる。また、加温の温度範囲については、有機溶剤の沸点を超えない範囲が特に好ましい。これは、加温時に加圧容器等を用いることなく加温できるからである。
【００２２】
次に、本発明の第１の方法では、金属塩を含む有機溶剤に脂肪族エステル−アミド共重合樹脂を溶解又は分散させた樹脂混合溶液と、水又は水溶液とを攪拌しながら混合する。この処理により、混合溶液中の有機溶剤、及び金属塩の全部又は一部が溶媒に溶出して除去されるため、脂肪族エステル−アミド共重合樹脂が析出する。このとき、混合溶液中で有機溶剤及び金属塩が占めていた部分が空間となって樹脂が析出し、脂肪族エステル−アミド共重合樹脂の多孔微粒子が得られる。ここで使用する溶媒としては、水及びアセトン水溶液が好ましい。
【００２３】
また、本発明の第２の方法では、金属塩を含む有機溶剤に脂肪族エステル−アミド共重合樹脂を溶解又は分散させた樹脂混合溶液と、脂肪族エステル−アミド共重合樹脂及び金属塩が不溶又は難溶でかつ有機溶剤が可溶な溶媒とを攪拌しながら混合する。この処理により、混合溶液中の有機溶剤が溶媒に溶出して除去されるため、脂肪族エステル−アミド共重合樹脂が析出する。このとき、混合溶液中で有機溶剤が占めていた部分が空間となって樹脂が析出し、金属塩を含む脂肪族エステル−アミド共重合樹脂の多孔微粒子が得られる。脂肪族エステル−アミド共重合樹脂及び金属塩が不溶又は難溶でかつ有機溶剤が可溶な溶媒としては、アセトン、メチルイソブチルケトン等のケトン類、ジエチルエーテル等が挙げられ、それらの中でもジエチルエーテルを用いるのが好ましい。
【００２４】
第１及び第２のいずれの方法によって得られる樹脂多孔微粒子も、溶液成形によって製造されるため、熱による劣化がなく、なおかつ均質なものとなる。
樹脂混合溶液と溶媒（水、水溶液、又は脂肪族エステル−アミド共重合樹脂及び金属塩が不溶もしくは難溶でかつ有機溶剤が可溶な溶媒を意味する。以下、同様。）とを混合する方法の態様としては、樹脂混合溶液から樹脂が析出して固化するまでに、微小な粒子として分散させ得る方法ならばいずれの方法であってもよいが、析出樹脂の合着を防止できるという点で、該溶媒中に樹脂混合溶液を滴下する方法が好ましい。溶媒の攪拌には、通常の液体の攪拌方法が利用でき、例えば攪拌翼を備えた攪拌軸を回転させる方法や、溶媒を入れた容器自体を回転させる方法、ノズル等から溶媒を勢いよく噴出して水流を発生させる方法などがある。
【００２５】
多孔微粒子の粒子径は、再析出時に使用する溶媒の種類、溶媒との混合方法や攪拌速度によって、また樹脂混合溶液における樹脂の種類、濃度等によって制御することができ、平均粒子径０．５ 〜５０μｍの範囲で任意に微粒子を形成することができる。また、多孔微粒子における孔径は、溶媒と混合する際の条件等によって、あるいは樹脂中での金属塩の分散状態によって制御することができる。
【００２６】
本発明の方法では過度の熱や剪断を加えることなく樹脂多孔微粒子を成形することができるので、樹脂の劣化はほとんどなく、再度溶解・分散させて繰り返し好適に使用することができる。
なお、脂肪族エステル−アミド共重合樹脂として、生分解性を有するようにアミド単位の割合を調整したものを使用した場合には、得られた樹脂多孔微粒子が不用意に廃棄されたとしても土中で分解するため、環境破壊のおそれがない。
【００２７】
本発明の樹脂多孔微粒子は、吸湿性を増大させる等のために、樹脂中に金属塩が残存していてもよく、また脂肪族エステル−アミド共重合樹脂以外にも、多孔微粒子の安定性を増すため等のために、通常使用される界面活性剤、酸化防止剤、可塑剤等を含有してもよく、再析出樹脂を着色するための染料、顔料等を含有してもよい。
【００２８】
本発明の脂肪族エステル−アミド共重合樹脂多孔微粒子は、各種フィルターの充填材や、吸湿性素材、さらには生分解性の共重合樹脂を利用して、生分解性の農林水産資材等に使用することができる。
【００２９】
【実施例】
以下、実施例を挙げて本発明を更に詳細に説明するが、これらの実施例は本発明の範囲を何等限定するものではない。
（実施例１）
ε−カプロラクトン（ダイセル化学社製：商標名「プラクセルＭ」）とε−カプロラクタム（三菱化学社製）とを金属ナトリウムを開始剤として開環重合させ、アミド成分の比率３０モル％、重量平均分子量１．４ ×１０４ の乳白色不透明の脂肪族エステル−アミド共重合樹脂を得た。
【００３０】
メタノール１００ 重量部に塩化カルシウム２５重量部を溶解させた溶解液に、上記で得られた脂肪族エステル−アミド共重合樹脂２５重量部を加え、約６０℃に加熱しながら攪拌して樹脂成分を均一に分散させた。得られた樹脂混合溶液は、６０℃では乳濁した粘稠な液体であり、室温下で放置すると固化して流動性を失った。この樹脂混合液を、メタノールにより重量比で１０倍に希釈した。
【００３１】
アセトン及び水を体積比１：２で混合したアセトン水溶液をマグネチックスターラーで攪拌しながら、上記樹脂混合溶液を滴下したところ、粒子状の樹脂が析出した。析出した樹脂を分離して乾燥させ、走査型電子顕微鏡で観察したところ、表面及び内部に多数の微細孔が認められる、粒子径がおよそ１〜１０μｍの均質な多孔微粒子であることがわかった。走査型電子顕微鏡による多孔微粒子の写真（倍率：５，０００ 倍）を図１に示す。
（比較例１）
実施例１と同様にして樹脂混合溶液及びアセトン水溶液を調製した。静置したアセトン水溶液に樹脂混合溶液を滴下したところ、樹脂は粒子状には分散せず、塊状で析出した。
（実施例２）
実施例１と同様にして、メタノールで１０倍（重量比）に希釈した樹脂混合溶液を調製した。この樹脂混合溶液をマグネチックスターラーで攪拌している水中に滴下したところ、粒子状の樹脂が析出した。実施例１と比較して粒子同士の合着が若干多く見られたが、析出した樹脂を分離して乾燥させ、走査型電子顕微鏡で観察したところ、粒子径がおよそ１〜２０μｍの均質な多孔微粒子であることがわかった。
（実施例３）
メタノールで３倍（重量比）に希釈する以外、実施例１と同様にして樹脂混合溶液を調製した。この樹脂混合溶液をマグネチックスターラーで攪拌しているジエチルエーテル中に滴下したところ、微粒子状の樹脂が析出した。析出した樹脂を分離して、相対湿度３０％、３０℃のインキュベーター中で乾燥させた後、相対湿度６０％の室内に放置したところ、微粒子中の塩化カルシウムの潮解により、微粒子が湿り気を帯びた。これによって、本実施例で得られた微粒子が優れた吸湿性を有することがわかった。
【００３２】
【発明の効果】
本発明によれば、毒性や環境汚染性の強い溶媒を使用しなくても、脂肪族エステル−アミド共重合樹脂多孔微粒子を容易に製造することができる。
【図面の簡単な説明】
【図１】実施例１で得られた樹脂多孔微粒子の形態についての走査型電子顕微鏡による写真を示す。倍率は５，０００ 倍である。[0001]
[Industrial applications]
The present invention relates to an aliphatic ester-amide copolymer resin porous fine particle having a predetermined average particle diameter and a method for producing the same.
[0002]
[Prior art]
Aliphatic ester-amide copolymer resin is an excellent resin that combines the toughness of an aliphatic amide resin with the good processability of an aliphatic ester, and can also have the biodegradability of an aliphatic ester. (See JP-B-56-38115, JP-B-57-26688, JP-A-6-200016, JP-A-6-192417, etc.).
[0003]
Generally, to form resin fine particles, the resin is heated and dissolved in a dispersion medium composed of an organic solvent or water in which the resin is insoluble, and then the molten resin is dispersed into fine particles by stirring and then cooled. In this case, a method of obtaining resin fine particles by the above method and a method of suspension polymerization are often used. However, in the case of an aliphatic ester-amide copolymer resin, when water is used as a dispersion medium, the resin is hydrolyzed, and particles are easily coalesced during cooling, so that it was very difficult to obtain fine particles. .
[0004]
In addition, after dissolving the resin in a solvent to form a solution, the resin is mixed and stirred in a dispersion medium composed of an organic solvent or water in which the resin is insoluble and the solvent is soluble. Although the method is often used, in order to make the aliphatic ester-amide copolymer resin into a solution state, formic acid, hexafluoro-2-propanol, m-cresol, etc., are extremely harmful to the human body, A solvent having high environmental destruction such as ozone layer depletion must be used, and a good solvent that is easy to handle is not known. As described above, a more practical method is known which can produce fine particles of the aliphatic ester-amide copolymer resin without deterioration such as hydrolysis and without using a solvent harmful to the human body and the environment. Not.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for easily producing an aliphatic ester-amide copolymer resin porous fine particle without using an organic solvent having a strong toxicity or environmental pollution, and an aliphatic ester obtained by the method. -To provide amide copolymer resin porous fine particles.
[0006]
[Means for Solving the Problems]
In light of the above problems, as a result of intensive studies, the present inventors have made an aliphatic ester-amide copolymer resin into a solution using an organic solvent such as methanol or ethanol containing a metal salt, and stirred in a state where the solvent was contained. While mixing with a predetermined solvent, the aliphatic ester-amide copolymer resin porous fine particles can be used without using a harmful organic solvent such as formic acid, hexafluoro-2-propanol, and m-cresol. Were obtained, and the present invention was completed.
[0007]
That is, the present invention is an aliphatic ester-amide copolymer resin porous fine particle having an average particle diameter of 0.5 to 50 μm.
Further, the present invention, a solution in which a metal salt is dissolved in an organic solvent containing or not containing water, a resin mixed solution in which an aliphatic ester-amide copolymer resin is dissolved or dispersed, and water or an aqueous solution. Are mixed while stirring to remove an organic solvent and a metal salt from the resin mixed solution, thereby precipitating an aliphatic ester-amide copolymer resin. Is a manufacturing method.
Further, the present invention provides a solution in which a metal salt is dissolved in an organic solvent containing or not containing water, a resin mixed solution in which an aliphatic ester-amide copolymer resin is dissolved or dispersed, and an aliphatic ester- An amide copolymer resin and a solvent in which the metal salt is insoluble or hardly soluble and the organic solvent is soluble are mixed with stirring to remove the organic solvent from the resin mixed solution, and the aliphatic ester-amide copolymer is removed. A method for producing porous fine particles of an aliphatic ester-amide copolymer resin, wherein a mixture of a resin and a metal salt is precipitated and made porous.
[0008]
Hereinafter, the present invention will be described in detail.
The aqueous solution referred to in the present invention refers to a solution using water as a solvent, which can precipitate an aliphatic ester-amide copolymer resin and can elute a metal salt, specifically, methanol, ethanol, It refers to an aqueous solution of an organic solvent such as acetone, an aqueous solution of a volatile acid or alkali, or an aqueous solution of a surfactant or the like.
[0009]
Further, the aliphatic ester-amide copolymer resin porous fine particles referred to in the present invention include a mixture of an aliphatic ester-amide copolymer resin and a metal salt.
In the method for producing porous fine particles of an aliphatic ester-amide copolymer resin of the present invention, first, an aliphatic ester-amide copolymer resin is dissolved or dispersed in an organic solvent containing a metal salt. The dissolution in the present invention means that the copolymer resin becomes a substantially uniform solution under heating at room temperature or in a range not exceeding the boiling point of the organic solvent, and the dispersion means at room temperature or the boiling point of the organic solvent. The separation of the organic solvent and the precipitation of the metal salt and the copolymer resin do not substantially occur under heating within the range not exceeding, and the copolymer resin and the organic solvent are in a substantially uniform state. This also includes the case where gelation of a part of the resin mixed solution or some separation of the organic solvent occurs (particularly at room temperature) in both dissolution and dispersion.
[0010]
The combination of the organic solvent and the metal salt used in the present invention may be any combination as long as the aliphatic ester-amide copolymer resin can be dissolved, and the copolymer resin is in a practically effective dissolved or dispersed state. In order to achieve this, it is preferable that the combination is such that the metal salt is dissolved in an amount of 1 part by weight or more with respect to 100 parts by weight of the organic solvent. Particularly preferred is a combination.
[0011]
Examples of the organic solvent include alcohols having a total carbon number of 6 or less in a continuous carbon chain, and the following chemical formula (1)
[0012]
Embedded image
(In the formula, R 1 represents an alkyl group having 1 to 4 carbon atoms, R 2 represents a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, an amino group or an acetic acid group, and n represents an integer of 1 to 3. )
And at least one compound selected from the group consisting of glycol ethers, organic acids having 5 or less carbon atoms, alkyl sulfoxides and aliphatic amides.
[0014]
Examples of the alcohol include methanol, ethanol, and ethylene glycol.Examples of glycol ethers include 2-methoxyethanol and 2-ethoxyethanol.Examples of the organic acid include acetic acid, and examples of the alkyl sulfoxide include: , Dimethylsulfoxide and the like, and the aliphatic amides include dimethylformamide, N-methyl-2-pyrrolidone and the like, and these can be used alone or in a suitable mixture.
[0015]
The boiling point of the organic solvent is preferably in the range of 30 to 250 ° C. in consideration of handleability at room temperature and ease of removing the solvent from the resin and drying. Particularly preferred organic solvents are methanol, ethanol and mixtures thereof.
The organic solvent described above may or may not contain water. Whether or not to include water or the content thereof may be appropriately selected depending on the usage form of the resin porous fine particles and the like. However, in order to obtain a mixed solution having a high resin content, it is preferable that the water content is low.
[0016]
On the other hand, as the metal salt used in the present invention, a halide, a nitrate and a thiocyanate of a metal selected from the groups Ia, IIa, Ib and IIb of the periodic table having an atomic number of 38 or less are preferable. They can be used in combination.
Specific examples include lithium chloride, calcium chloride, magnesium chloride, zinc chloride, lithium bromide, calcium bromide, magnesium bromide, zinc bromide, calcium nitrate, magnesium nitrate, zinc nitrate and the like. In particular, when a metal salt having a deliquescent property, for example, calcium chloride is used, by leaving a required amount of the metal salt in the porous fine particles, the resulting aliphatic ester-amide copolymer resin porous fine particles are excellent. It will be hygroscopic.
[0017]
The mixing ratio of the metal salt to the organic solvent is preferably 1 to 40 parts by weight, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the organic solvent. When the mixing ratio of the metal salt is smaller than the above range, the amount of the obtained resin porous fine particles is small, and when the mixing ratio is larger than the above range, precipitation of the metal salt is likely to occur, and it is difficult to form a uniform resin mixed solution.
[0018]
The aliphatic ester-amide copolymer resin in the present invention may be any resin as long as the aliphatic ester and the aliphatic amide are copolymerized. Group unit represented by the following chemical formula (2)
—OR 3 —CO— (2)
(In the formula, R 3 represents a linear methylene group having 1 to 6 carbon atoms or a group in which an alkyl group having 1 to 3 carbon atoms is bonded to the linear methylene.)
And / or the following chemical formula (3)
—OR 4 —OCO—R 5 —CO— (3)
(Wherein, R 4 is a C 2-6, R 6 is a C 2-10 linear methylene group or a group in which an alkyl group having 1 to 3 carbon atoms is bonded to the linear methylene group. Represents.)
Wherein the aliphatic amide unit is represented by the following chemical formula (4)
—NH—R 6 —CO— (4)
(In the formula, R 6 represents a linear methylene group having 2 to 12 carbon atoms or a group in which an alkyl group having 1 to 3 carbon atoms is bonded to the linear methylene.)
And / or the following chemical formula (5)
—NH—R 7 —NHCO—R 8 —CO— (5)
(Wherein, R 7 is a C 2 -C 6, R 8 is a C 2 -C 10 linear methylene group or a group in which an alkyl group having 1 to 3 carbon atoms is bonded to these linear methylenes. Represents.)
It is preferable that they have a structure represented by the following formula: The form of copolymerization may be ordinary copolymerization, block copolymerization, graft copolymerization, or alternating copolymerization. Further, in the aliphatic ester-amide copolymer resin of the present invention, a small amount of a molecular extender added for the purpose of bonding together polymers and further polymerizing, specifically, diisocyanate, polybasic acid, etc. A derived structure can be included.
[0019]
The proportion of amide units in the main chain of the aliphatic ester-amide copolymer resin is preferably from 10 to 80 mol% in order to improve the processability of the copolymer resin, and further to impart biodegradability. Is preferably 10 to 60 mol%.
The weight average molecular weight of the aliphatic ester-amide copolymer resin is preferably from 5,000 to 500,000. If it is 5,000 or more, the physical properties of the porous resin fine particles are good and the practical range is wide, and if it is 500,000 or less, the synthesis time can be shortened and the reaction conditions such as the degree of vacuum can be eased.
[0020]
The mixing ratio of the aliphatic ester-amide copolymer resin to the organic solvent containing the metal salt is preferably 1 to 30 parts by weight of the copolymer resin to 100 parts by weight of the organic solvent containing the metal salt, and 1 to 20 parts by weight. More preferably, it is part by weight. If the mixing ratio of the copolymer resin is smaller than this range, it takes a lot of time and effort to remove and recover the solvent and the metal salt, so that it is not practical. Sufficient precipitation is likely to occur, and the viscosity of the mixed solution also increases, making it difficult to form fine particles.
[0021]
The water contained as crystallization water in the metal salt may remain in the resin mixed solution, but its water content is determined by dissolving or dispersing the aliphatic ester-amide copolymer resin when the resin is dissolved or dispersed. May be appropriately controlled within a range in which the occurrence does not occur.
When dissolving or dispersing the aliphatic ester-amide copolymer resin in the solution, it is preferable to heat. By heating in this way, the aliphatic ester-amide copolymer resin can be dissolved or dispersed in a short time. As for the heating temperature range, a range not exceeding the boiling point of the organic solvent is particularly preferable. This is because heating can be performed without using a pressurized container or the like at the time of heating.
[0022]
Next, in the first method of the present invention, a resin mixed solution in which an aliphatic ester-amide copolymer resin is dissolved or dispersed in an organic solvent containing a metal salt, and water or an aqueous solution are mixed with stirring. By this treatment, all or a part of the organic solvent and the metal salt in the mixed solution are eluted and removed from the solvent, so that the aliphatic ester-amide copolymer resin is precipitated. At this time, the portion occupied by the organic solvent and the metal salt in the mixed solution becomes a space to precipitate the resin, and porous fine particles of the aliphatic ester-amide copolymer resin are obtained. As the solvent used here, water and an acetone aqueous solution are preferable.
[0023]
Further, in the second method of the present invention, a resin mixed solution in which an aliphatic ester-amide copolymer resin is dissolved or dispersed in an organic solvent containing a metal salt, and the aliphatic ester-amide copolymer resin and the metal salt are insoluble. Alternatively, a solvent that is hardly soluble and in which the organic solvent is soluble is mixed with stirring. By this treatment, the organic solvent in the mixed solution is eluted into the solvent and removed, so that the aliphatic ester-amide copolymer resin is precipitated. At this time, the portion occupied by the organic solvent in the mixed solution becomes a space to precipitate the resin, and porous fine particles of an aliphatic ester-amide copolymer resin containing a metal salt are obtained. Examples of the solvent in which the aliphatic ester-amide copolymer resin and the metal salt are insoluble or hardly soluble and the organic solvent is soluble include ketones such as acetone and methyl isobutyl ketone, and diethyl ether. It is preferable to use
[0024]
Since the resin porous fine particles obtained by any of the first and second methods are manufactured by solution molding, they are not deteriorated by heat and are uniform.
A method of mixing a resin mixed solution with a solvent (water, an aqueous solution, or a solvent in which an aliphatic ester-amide copolymer resin and a metal salt are insoluble or hardly soluble and an organic solvent is soluble. The same applies hereinafter). As an aspect of the method, any method may be used as long as it can be dispersed as fine particles until the resin is precipitated and solidified from the resin mixed solution, but it is possible to prevent coalescence of the precipitated resin. A method of dropping a resin mixed solution into the solvent is preferred. For stirring the solvent, a normal liquid stirring method can be used, for example, a method of rotating a stirring shaft equipped with a stirring blade, a method of rotating the container itself containing the solvent, a vigorous ejection of the solvent from a nozzle or the like. To generate a water flow.
[0025]
The particle diameter of the porous fine particles can be controlled by the type of solvent used during reprecipitation, the method of mixing with the solvent and the stirring speed, and the type and concentration of the resin in the resin mixed solution. Fine particles can be arbitrarily formed in a range of from 50 μm to 50 μm. Further, the pore size of the porous fine particles can be controlled by the conditions at the time of mixing with the solvent, or by the dispersion state of the metal salt in the resin.
[0026]
According to the method of the present invention, the resin porous fine particles can be molded without applying excessive heat or shearing. Therefore, there is almost no deterioration of the resin, and the resin can be dissolved and dispersed again and used repeatedly and suitably.
When an aliphatic ester-amide copolymer resin whose proportion of amide units is adjusted so as to have biodegradability is used as the aliphatic ester-amide copolymer resin, even if the obtained resin microparticles are inadvertently discarded, they may be soiled. Since it decomposes in the environment, there is no risk of environmental destruction.
[0027]
The resin porous fine particles of the present invention may have a metal salt remaining in the resin in order to increase the hygroscopicity and the like.Also, other than the aliphatic ester-amide copolymer resin, the stability of the porous fine particles may be improved. In order to increase the amount, a surfactant, an antioxidant, a plasticizer and the like which are usually used may be contained, and a dye, a pigment and the like for coloring the reprecipitated resin may be contained.
[0028]
The porous fine particles of the aliphatic ester-amide copolymer resin of the present invention are used for biodegradable agriculture, forestry and fishery materials, etc. by utilizing fillers for various filters, hygroscopic materials, and even biodegradable copolymer resins. can do.
[0029]
【Example】
Hereinafter, the present invention will be described in more detail by way of examples, but these examples do not limit the scope of the present invention in any way.
(Example 1)
Ring-opening polymerization of ε-caprolactone (manufactured by Daicel Chemical Co., Ltd .: trade name “Placcel M”) and ε-caprolactam (manufactured by Mitsubishi Chemical Co., Ltd.) using metal sodium as an initiator, the ratio of the amide component is 30 mol%, and the weight average molecular weight A milky white opaque aliphatic ester-amide copolymer resin of 1.4 × 10 4 was obtained.
[0030]
To a solution obtained by dissolving 25 parts by weight of calcium chloride in 100 parts by weight of methanol is added 25 parts by weight of the aliphatic ester-amide copolymer resin obtained above, and the mixture is stirred while heating to about 60 ° C. to remove the resin component. Dispersed uniformly. The obtained resin mixed solution was a viscous liquid which was emulsified at 60 ° C., and solidified when left at room temperature to lose fluidity. This resin mixture was diluted 10 times by weight with methanol.
[0031]
The above resin mixture solution was dropped while stirring an acetone aqueous solution obtained by mixing acetone and water at a volume ratio of 1: 2 with a magnetic stirrer. As a result, a particulate resin was precipitated. The precipitated resin was separated, dried, and observed with a scanning electron microscope. As a result, it was found that the resin was homogeneous porous fine particles having a number of fine pores on the surface and inside, and a particle diameter of about 1 to 10 μm. FIG. 1 shows a photograph (magnification: 5,000 times) of the porous fine particles taken by a scanning electron microscope.
(Comparative Example 1)
A resin mixed solution and an aqueous acetone solution were prepared in the same manner as in Example 1. When the resin mixture solution was dropped into the acetone aqueous solution that had been allowed to stand, the resin did not disperse into particles but precipitated in a lump.
(Example 2)
In the same manner as in Example 1, a resin mixed solution diluted 10 times (weight ratio) with methanol was prepared. When this resin mixed solution was dropped into water stirred with a magnetic stirrer, particulate resin was precipitated. Although coalescence between the particles was slightly larger than that in Example 1, the precipitated resin was separated, dried, and observed with a scanning electron microscope. It turned out to be fine particles.
(Example 3)
A resin mixed solution was prepared in the same manner as in Example 1 except for diluting with methanol three times (weight ratio). When this resin mixed solution was dropped into diethyl ether stirred with a magnetic stirrer, fine resin particles were precipitated. The precipitated resin was separated, dried in an incubator at 30% relative humidity and 30 ° C., and then left in a room with a relative humidity of 60%. The fine particles became moist due to the deliquescence of calcium chloride in the fine particles. . As a result, it was found that the fine particles obtained in this example had excellent hygroscopicity.
[0032]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, an aliphatic ester-amide copolymer resin porous fine particle can be easily manufactured, without using a solvent with strong toxicity and environmental pollution.
[Brief description of the drawings]
FIG. 1 shows a scanning electron microscope photograph of the form of porous resin fine particles obtained in Example 1. The magnification is 5,000 times.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16016895A JP3570782B2 (en) | 1995-06-05 | 1995-06-05 | Aliphatic Ester-Amide Copolymer Resin Porous Fine Particles and Production Method Thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16016895A JP3570782B2 (en) | 1995-06-05 | 1995-06-05 | Aliphatic Ester-Amide Copolymer Resin Porous Fine Particles and Production Method Thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08325406A JPH08325406A (en) | 1996-12-10 |
| JP3570782B2 true JP3570782B2 (en) | 2004-09-29 |
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| Country | Link |
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| JP (1) | JP3570782B2 (en) |
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| JPH08325406A (en) | 1996-12-10 |
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