JP3440915B2 - Polylactic acid resin and molded products - Google Patents
Polylactic acid resin and molded productsInfo
- Publication number
- JP3440915B2 JP3440915B2 JP2000070098A JP2000070098A JP3440915B2 JP 3440915 B2 JP3440915 B2 JP 3440915B2 JP 2000070098 A JP2000070098 A JP 2000070098A JP 2000070098 A JP2000070098 A JP 2000070098A JP 3440915 B2 JP3440915 B2 JP 3440915B2
- Authority
- JP
- Japan
- Prior art keywords
- polylactic acid
- acid resin
- plla
- chip
- terminal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Landscapes
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Polyesters Or Polycarbonates (AREA)
- Biological Depolymerization Polymers (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ポリ乳酸樹脂およ
びその成形品に関し、さらに詳細には酸末端が封鎖され
耐加水分解性が向上されたポリ乳酸樹脂およびその成形
品に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polylactic acid resin and a molded article thereof, and more particularly to a polylactic acid resin having an acid terminal blocked and improved hydrolysis resistance and a molded article thereof.
【０００２】[0002]
【従来の技術】従来、プラスチック廃棄物は主に焼却や
埋め立てにより処理されてきたが、焼却による有害副産
物の生成・排出や埋立地の減少、さらには不法投棄によ
る環境汚染などの問題が顕在化してきている。このよう
なプラスチック廃棄物の処理問題について社会的に関心
が高まるにつれて、酵素や微生物で分解される生分解性
を有するプラスチックの研究開発が盛んに行われてお
り、その中でも、脂肪族ポリエステルが注目されてい
る。最近、特に積極的な研究開発が行われている生分解
性の脂肪族ポリエステルとしては、ポリ乳酸、ポリグリ
コール酸、ポリ（３−ヒドロキシブチレート）、ポリ
（３−ヒドロキシブチレート・３−ヒドロキシバリレー
ト）、ポリカプロラクトン、あるいはエチレングリコー
ル、１，４−ブタンジオールなどのグリコールとコハク
酸、アジピン酸などのカルボン酸よりなるポリエステル
などが知られている。その中でも、耐熱性が高く力学特
性や生分解性などの諸特性に優れることから、ポリ乳酸
が特に注目されている。2. Description of the Related Art Conventionally, plastic waste has been mainly treated by incineration or landfill, but problems such as generation and discharge of harmful by-products due to incineration, reduction of landfill, and environmental pollution due to illegal dumping have become apparent. I'm doing it. With increasing social concern about such plastic waste treatment problems, research and development of biodegradable plastics that are decomposed by enzymes and microorganisms are being actively conducted, and among them, aliphatic polyesters are attracting attention. Has been done. As biodegradable aliphatic polyesters which have been particularly actively researched and developed recently, polylactic acid, polyglycolic acid, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate-3-hydroxy) are available. Valylate), polycaprolactone, or polyesters comprising glycols such as ethylene glycol and 1,4-butanediol and carboxylic acids such as succinic acid and adipic acid are known. Among them, polylactic acid has been particularly attracting attention because it has high heat resistance and is excellent in various properties such as mechanical properties and biodegradability.
【０００３】しかしながら、ポリ乳酸は室温や高温の水
中における加水分解性が非常に高く、さらには空気中の
水分によっても分解されうるという性質を持っている。
このように容易に加水分解される性質により、例えば繊
維やスリットフィルムとして使用する場合では、染料の
水分散溶液による高温での染色を行うと布帛の引裂強度
が急激に低下してしまうことから比較的低温での染色し
か行えず濃色に染めることができない、あるいは漁網な
どの水産資材用として水中で使用する場合にはその使用
可能期間がごく短期間に限定されてしまう、さらには経
時安定性に乏しく製造後長期間経た後では劣化のため当
初の性能が発揮できないといった問題点があった。ま
た、繊維やフィルム関連で種々の乾熱加工時や高温雰囲
気中での使用に際して、空気中の水分による加水分解が
問題となる場合があった。そのため従来から医療用途な
どごく限られた用途でしか使用できず、汎用用途への展
開においては、これらの問題の解決が必要であった。However, polylactic acid has a very high hydrolyzability in water at room temperature or high temperature, and has the property that it can be decomposed by water in the air.
Due to the property of being easily hydrolyzed in this way, for example, when used as a fiber or a slit film, when the dyeing is performed at a high temperature with an aqueous dispersion solution of the dye, the tear strength of the fabric is sharply reduced. It can only be dyed at extremely low temperatures and cannot be dyed in dark colors, or when used in water for fisheries materials such as fishing nets, its usable period is limited to a very short period of time, and it is stable over time. However, there is a problem that the initial performance cannot be exhibited due to deterioration after a long period of time after manufacturing. Further, there are cases where hydrolysis due to moisture in the air poses a problem during various dry heat processings and in use in a high temperature atmosphere related to fibers and films. Therefore, it can be used only for very limited applications such as medical applications from the past, and it has been necessary to solve these problems in the development of general-purpose applications.
【０００４】このような問題点を解決する手段として、
特開平７−３１６２７３号公報にはポリ乳酸のカルボキ
シル基末端を脂肪族アルコールとの縮合反応により末端
封鎖する技術が開示されている。しかしながら、この技
術は縮合反応であり、反応副産物を除去するためにポリ
乳酸を重合する際に脂肪族アルコールを共存させる必要
があり、そのために重合速度が遅く工業的な生産ができ
ない、残存低分子量未反応物が多くこれらが成形時に気
化するため成形品の外観が劣るあるいは成形品の耐熱性
が低いなどの問題点や、さらには縮合反応により得られ
た末端封鎖ポリマー（チップ）を再溶融・成形する際に
再びカルボキシル基末端が生成してしまい、未封鎖末端
が残存するために成形品の耐加水分解性が依然として不
十分であるといった問題点があった。また、特開平９−
２１０１７号公報には、脂肪族アルコールによるカルボ
キシル基末端の封鎖に加えて紡糸温度を低くすることに
より、ポリ乳酸繊維のカルボキシル基末端濃度を下げる
技術が開示されている。しかしながら、ポリ乳酸の溶融
粘度は温度依存性が比較的高いため、紡糸温度を下げる
ためにはポリマーの分子量を十分に下げる必要があり、
汎用繊維やフィルムなどとして十分な強度を有するポリ
乳酸繊維を得ることができないといった問題点があっ
た。さらに、特開平１１−８０５２２号公報には、耐加
水分解性向上を目的として生分解性プラスチックにカル
ボジイミド化合物を配合する技術が開示されている。し
かしながら、該公報に開示されているモノカルボジイミ
ド化合物では耐熱性が不足しこれらがプラスチック成形
時に気化するため十分な効果が得られない、成形品の耐
熱性が低いあるいは成形品の外観が劣るなどの問題があ
った。また、同じく開示されているポリカルボジイミド
化合物では、成形時にゲル化が起こるために均質な成形
品とすることが困難であるといった問題があった。As a means for solving such a problem,
Japanese Unexamined Patent Publication (Kokai) No. 7-316273 discloses a technique of end-capping a carboxyl group end of polylactic acid by a condensation reaction with an aliphatic alcohol. However, this technique is a condensation reaction, and it is necessary to make an aliphatic alcohol coexist when polymerizing polylactic acid in order to remove a reaction by-product, and therefore the polymerization rate is slow and industrial production is not possible. There are many unreacted substances, and these are vaporized during molding, so the appearance of the molded product is inferior or the heat resistance of the molded product is low. Furthermore, the end-capped polymer (chip) obtained by the condensation reaction is remelted. There was a problem that the carboxyl group terminal was generated again during molding and the unblocked terminal remained, so that the hydrolysis resistance of the molded product was still insufficient. In addition, JP-A-9-
Japanese Patent No. 21017 discloses a technique of lowering the concentration of carboxyl group terminals of polylactic acid fiber by lowering the spinning temperature in addition to blocking the carboxyl group terminals with an aliphatic alcohol. However, since the melt viscosity of polylactic acid has a relatively high temperature dependence, it is necessary to sufficiently lower the molecular weight of the polymer in order to lower the spinning temperature.
There is a problem that polylactic acid fibers having sufficient strength cannot be obtained as general-purpose fibers or films. Further, JP-A No. 11-80522 discloses a technique of blending a carbodiimide compound with a biodegradable plastic for the purpose of improving hydrolysis resistance. However, in the monocarbodiimide compound disclosed in the publication, heat resistance is insufficient and these are vaporized at the time of plastic molding, so that a sufficient effect cannot be obtained, heat resistance of the molded product is low, or appearance of the molded product is poor. There was a problem. Further, the polycarbodiimide compound also disclosed has a problem that it is difficult to form a homogeneous molded product because gelation occurs during molding.
【０００５】以上のように、従来からポリ乳酸のカルボ
キシル基末端濃度を下げることで耐加水分解性を向上さ
せようとする試みはなされていたものの、実用的に十分
な高い分子量や耐熱性および耐加水分解性を兼ね備えた
ポリ乳酸からなる繊維やフィルムなどの成形品について
は未だ達成されていないのが実状であった。As described above, although attempts have been made so far to improve the hydrolysis resistance by lowering the carboxyl group terminal concentration of polylactic acid, a practically high molecular weight, heat resistance and resistance It has been the actual situation that molded articles such as fibers and films made of polylactic acid having hydrolyzability have not yet been achieved.
【０００６】[0006]
【発明が解決しようとする課題】本発明の課題は、従来
技術ではなしえなかった実用的に十分な高い分子量や耐
熱性および耐加水分解性を兼ね備えたポリ乳酸樹脂、お
よび繊維やフィルム等の成形品を提供することにある。The object of the present invention is to provide a polylactic acid resin having a practically sufficiently high molecular weight, heat resistance and hydrolysis resistance, which cannot be achieved by the prior art, and fibers, films and the like. It is to provide molded products.
【０００７】[0007]
【課題を解決するための手段】上記課題を解決するため
本発明のポリ乳酸樹脂は、５％重量減少温度が１７０℃
以上のモノカルボジイミド化合物によりポリ乳酸のカル
ボキシル基末端のうち一部または実質的に全部が封鎖さ
れていることを特徴とするポリ乳酸樹脂であり、このポ
リ乳酸樹脂は繊維およびフィルム等の成形品に好適に用
いられる。In order to solve the above problems, the polylactic acid resin of the present invention has a 5% weight loss temperature of 170 ° C.
A polylactic acid resin characterized in that a part or substantially all of the carboxyl group terminals of polylactic acid are blocked by the above monocarbodiimide compound, and this polylactic acid resin is used for molded articles such as fibers and films. It is preferably used.
【０００８】[0008]
【発明の実施の形態】次に、本発明のポリ乳酸樹脂につ
いて説明する。BEST MODE FOR CARRYING OUT THE INVENTION Next, the polylactic acid resin of the present invention will be described.
【０００９】本発明でいうポリ乳酸とは、Ｌ−乳酸およ
び／またはＤ―乳酸を主成分とするポリ乳酸を意味す
る。The polylactic acid in the present invention means polylactic acid containing L-lactic acid and / or D-lactic acid as a main component.
【００１０】ポリ乳酸の製造方法には、Ｌ−乳酸、Ｄ−
乳酸、ＤＬ−乳酸（ラセミ体）を原料として一旦環状２
量体であるラクチドを生成せしめ、その後開環重合を行
う２段階のラクチド法と、当該原料を溶媒中で直接脱水
縮合を行う一段階の直接重合法が知られている。本発明
においてポリ乳酸を用いる場合はいずれの製法によって
得られたものであってもよいが、ラクチド法によって得
られるポリマーの場合にはポリマー中に含有される環状
２量体が成形時に気化して、例えば溶融紡糸時には糸斑
の原因となるため、成形時あるいは溶融紡糸以前の段階
でポリマー中に含有される環状２量体の含有量を０．３
ｗｔ％以下とすることが望ましい。また、直接重合法の
場合には環状２量体に起因する問題が実質的にないた
め、成型性あるいは製糸性の観点からはより好適であ
る。本発明においてポリ乳酸の重量平均分子量は高いほ
ど好ましく、通常少なくとも５万、好ましくは少なくと
も８万、好ましくは１０〜３０万、さらに好ましくは１
０万〜２０万である。平均分子量をかかる範囲とする場
合には、繊維やフィルムなどの成形品とした場合の強度
物性を優れたものとすることができる。なお、一般にポ
リ乳酸の平均分子量を４０万以上とすることは困難であ
る。The method for producing polylactic acid includes L-lactic acid and D-lactic acid.
Cyclic 2 using lactic acid and DL-lactic acid (racemic) as raw materials
A two-step lactide method in which a lactide which is a monomer is produced and then ring-opening polymerization is performed, and a one-step direct polymerization method in which the raw material is directly dehydrated and condensed in a solvent are known. When polylactic acid is used in the present invention, it may be obtained by any production method, but in the case of a polymer obtained by the lactide method, the cyclic dimer contained in the polymer is vaporized during molding. For example, since it causes yarn unevenness during melt spinning, the content of the cyclic dimer contained in the polymer at the time of molding or before melt spinning is 0.3%.
It is desirable to set it to be wt% or less. Further, in the case of the direct polymerization method, since there is substantially no problem caused by the cyclic dimer, it is more suitable from the viewpoint of moldability or yarn formability. In the present invention, the higher the weight average molecular weight of the polylactic acid is, the more preferable it is, usually at least 50,000, preferably at least 80,000, preferably 100,000 to 300,000, more preferably 1
It is from 0,000 to 200,000. When the average molecular weight is within such a range, the strength physical properties of a molded product such as a fiber or a film can be made excellent. In addition, it is generally difficult to set the average molecular weight of polylactic acid to 400,000 or more.
【００１１】また、本発明において好ましく用いられる
ポリ乳酸は、Ｌ−乳酸、Ｄ−乳酸のほかにエステル形成
能を有するその他の単量体成分を共重合した共重合ポリ
乳酸であってもよい。共重合可能な単量体成分として
は、グリコール酸、３−ヒドロキシ酪酸、４−ヒドロキ
シ酪酸、４−ヒドロキシ吉草酸、６−ヒドロキシカプロ
ン酸などのヒドロキシカルボン酸類の他、エチレングリ
コール、プロピレングリコール、ブタンジオール、ネオ
ペンチルグリコール、ポリエチレングリコール、グリセ
リン、ペンタエリスリトール等の分子内に複数の水酸基
を含有する化合物類またはそれらの誘導体、コハク酸、
アジピン酸、セバシン酸、フマル酸、テレフタル酸、イ
ソフタル酸、２，６−ナフタレンジカルボン酸、５−ナ
トリウムスルホイソフタル酸、５−テトラブチルホスホ
ニウムスルホイソフタル酸等の分子内に複数のカルボン
酸基を含有する化合物類またはそれらの誘導体が挙げら
れる。The polylactic acid preferably used in the present invention may be a copolymerized polylactic acid obtained by copolymerizing L-lactic acid and D-lactic acid with other monomer components having an ester forming ability. Examples of the copolymerizable monomer component include hydroxycarboxylic acids such as glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid and 6-hydroxycaproic acid, as well as ethylene glycol, propylene glycol and butane. Compounds having a plurality of hydroxyl groups in the molecule such as diol, neopentyl glycol, polyethylene glycol, glycerin, pentaerythritol or their derivatives, succinic acid,
Contains multiple carboxylic acid groups in the molecule such as adipic acid, sebacic acid, fumaric acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium sulfoisophthalic acid Compounds or derivatives thereof.
【００１２】また、ポリ乳酸の溶融粘度を低減させるた
め、ポリカプロラクトン、ポリブチレンサクシネート、
ポリエチレンサクシネートのような脂肪族ポリエステル
ポリマーを内部可塑剤として、あるいは外部可塑剤とし
て用いることができる。In order to reduce the melt viscosity of polylactic acid, polycaprolactone, polybutylene succinate,
Aliphatic polyester polymers such as polyethylene succinate can be used as internal plasticizers or as external plasticizers.
【００１３】なお、本発明のポリ乳酸樹脂には、本発明
の効果を損なわない範囲でポリ乳酸以外の成分を含有し
てもよい。例えば、可塑剤、紫外線安定化剤、着色防止
剤、艶消し剤、消臭剤、難燃剤、耐候剤、帯電防止剤、
糸摩擦低減剤、離型剤、抗酸化剤、イオン交換剤あるい
は着色顔料等として無機微粒子や有機化合物を必要に応
じて添加してもよい。着色顔料としてはカーボンブラッ
ク、酸化チタン、酸化亜鉛、酸化鉄などの無機顔料の
他、シアニン系、スチレン系、フタロシアイン系、アン
スラキノン系、ペリノン系、イソインドリノン系、キノ
フタロン系、キノクリドン系、チオインディゴ系などの
ものを使用することができる。また、炭酸カルシウムや
シリカなどの改質剤も使用することができる。The polylactic acid resin of the present invention may contain components other than polylactic acid as long as the effects of the present invention are not impaired. For example, plasticizer, ultraviolet stabilizer, anti-coloring agent, matting agent, deodorant, flame retardant, weathering agent, antistatic agent,
If necessary, inorganic fine particles or organic compounds may be added as a thread friction reducing agent, a release agent, an antioxidant, an ion exchanger, a coloring pigment, or the like. Coloring pigments include inorganic pigments such as carbon black, titanium oxide, zinc oxide, and iron oxide, as well as cyanine-based, styrene-based, phthalocyanine-based, anthraquinone-based, perinone-based, isoindolinone-based, quinophthalone-based, and quinocridone-based pigments. , Thioindigo, etc. can be used. Also, modifiers such as calcium carbonate and silica can be used.
【００１４】本発明のポリ乳酸樹脂は、５％重量減少温
度（以下、Ｔ5%と示す。）が１７０℃以上のモノカルボ
ジイミド化合物によりポリ乳酸のカルボキシル基末端の
うち一部または実質的に全部が封鎖されていることを特
徴とするポリ乳酸樹脂である。The polylactic acid resin of the present invention contains a monocarbodiimide compound having a 5% weight loss temperature (hereinafter referred to as T 5% ) of 170 ° C. or higher, so that a part or substantially all of the carboxyl group end of polylactic acid is used. Is a polylactic acid resin.
【００１５】本発明のポリ乳酸樹脂に用いる末端封鎖剤
は、Ｔ5%が１７０℃以上のモノカルボジイミド化合物で
ある必要がある。Ｔ5%が１７０℃未満のモノカルボジイ
ミド化合物では、樹脂成形時に添加した末端封鎖剤が分
解および／または気化してしまい成形品の耐熱性や品位
が低下する、末端封鎖剤がポリ乳酸のカルボキシル末端
に有効に反応・作用せず十分な耐加水分解性の向上効果
を得られない、製膜や製糸などの成形時においてはフィ
ルム破れや糸切れが頻発する等の問題がある。また、ポ
リカルボジイミド化合物では、樹脂中への分散性が比較
的低いため十分な付加反応が起こりにくく耐加水分解性
を十分に向上させることが困難であること、成形時にゲ
ル化が起こるために均質な成形品とすることが困難であ
ること、さらには製膜や製糸などの成形時においては安
定した工業的生産が困難である等の問題がある。The terminal blocking agent used in the polylactic acid resin of the present invention must be a monocarbodiimide compound having T 5% of 170 ° C. or higher. With a monocarbodiimide compound having T 5% of less than 170 ° C., the end-capping agent added during resin molding is decomposed and / or vaporized to lower the heat resistance and quality of the molded product. However, there is a problem that they do not react and act effectively and cannot obtain a sufficient effect of improving the hydrolysis resistance, and that film breakage or yarn breakage frequently occurs during the formation of a film or yarn. Further, in the polycarbodiimide compound, since the dispersibility in the resin is relatively low, it is difficult to sufficiently perform the addition reaction, and it is difficult to sufficiently improve the hydrolysis resistance. However, there are problems that it is difficult to obtain a molded product that is stable, and that stable industrial production is difficult at the time of molding such as film formation and yarn production.
【００１６】例えば、シクロヘキシルカルボジイミド、
ジイソプロピルカルボジイミドなどのＴ5%が１７０℃未
満のモノカルボジイミド化合物では、これらの化合物を
樹脂改質剤として使用する場合、上述したように樹脂成
形温度における耐熱性が低いことなどが問題となってい
たのに対し、本発明では、Ｔ5%が１７０℃以上のモノカ
ルボジイミド化合物を末端封鎖剤として使用すること
で、上述したＴ5%が１７０℃未満のモノカルボジイミド
化合物で問題となっていたポリマー成形時の末端封鎖剤
の分解および／または気化を抑制し、成形品の耐熱性や
品位の低下を抑えることができる。また、樹脂成形時の
分解および／または気化が抑えられることで反応性に優
れるモノカルボジイミド化合物が有効にポリ乳酸のカル
ボキシル基末端に反応・作用し十分な耐加水分解性の向
上効果が得られると同時に製膜や製糸などの成形時にお
いても良好な工程安定性と生産性を兼ね備えた生産が可
能となるものである。同様の観点から、本発明のポリ乳
酸樹脂に用いる末端封鎖剤は、Ｔ5%が１９０℃以上のモ
ノカルボジイミド化合物であることが好ましい。なお、
ここで５％重量減少温度とは実施例に記載の条件により
ＴＧ−ＤＴＡ測定により求めた温度をいう。For example, cyclohexylcarbodiimide,
With monocarbodiimide compounds having T 5% of less than 170 ° C. such as diisopropylcarbodiimide, when these compounds are used as resin modifiers, there has been a problem that the heat resistance at the resin molding temperature is low as described above. On the other hand, in the present invention, by using a monocarbodiimide compound having T 5% of 170 ° C. or higher as an end-capping agent, the above-mentioned polymer molding which has been a problem with the monocarbodiimide compound having T 5% of less than 170 ° C. It is possible to suppress decomposition and / or vaporization of the terminal blocking agent at this time, and to suppress deterioration of heat resistance and quality of the molded product. Further, when the decomposition and / or vaporization at the time of resin molding is suppressed, the monocarbodiimide compound having excellent reactivity effectively reacts and acts on the carboxyl group terminal of polylactic acid, and a sufficient hydrolysis resistance improving effect is obtained. At the same time, it is possible to perform production with good process stability and productivity even when forming a film or a yarn. From the same viewpoint, the terminal blocking agent used in the polylactic acid resin of the present invention is preferably a monocarbodiimide compound having T 5% of 190 ° C. or higher. In addition,
Here, the 5% weight loss temperature means the temperature determined by TG-DTA measurement under the conditions described in the examples.
【００１７】本発明に用いることのできるモノカルボジ
イミド化合物の例としては、例えば、Ｎ，Ｎ´−ジ−
２，６−ジイソプロピルフェニルカルボジイミド、Ｎ，
Ｎ´−ジ−２，６−ジ−tert. −ブチルフェニルカルボ
ジイミド、Ｎ，Ｎ′−ジ−２，６−ジエチルフェニルカ
ルボジイミド、Ｎ，Ｎ′−ジ−２−エチル−６−イソプ
ロピルフェニルカルボジイミド、Ｎ，Ｎ′−ジ−２−イ
ソブチル−６−イソプロピルフェニルカルボジイミド、
Ｎ，Ｎ′−ジ−２，４，６−トリメチルフェニルカルボ
ジイミド、Ｎ，Ｎ′−ジ−２，４，６−トリイソプロピ
ルフェニルカルボジイミド、Ｎ，Ｎ′−ジ−２，４，６
−トリイソブチルフェニルカルボジイミドなどが挙げら
れる。さらには、これらのモノカルボジイミド化合物の
中から１種または２種以上の化合物を任意に選択してポ
リ乳酸のカルボキシル末端を封鎖すればよいが、耐熱性
および反応性やポリ乳酸との親和性の点でＮ，Ｎ´−ジ
−２，６−ジイソプロピルフェニルカルボジイミド（以
下、ＴＩＣという。）が好ましく、２種以上のモノカル
ボジイミド化合物を併用する場合は、末端封鎖剤として
用いるモノカルボジイミド化合物の総量のうち５０％以
上がＴＩＣであることが好ましい。Examples of monocarbodiimide compounds that can be used in the present invention include, for example, N, N'-di-
2,6-diisopropylphenylcarbodiimide, N,
N'-di-2,6-di-tert.-butylphenylcarbodiimide, N, N'-di-2,6-diethylphenylcarbodiimide, N, N'-di-2-ethyl-6-isopropylphenylcarbodiimide, N, N'-di-2-isobutyl-6-isopropylphenylcarbodiimide,
N, N'-di-2,4,6-trimethylphenylcarbodiimide, N, N'-di-2,4,6-triisopropylphenylcarbodiimide, N, N'-di-2,4,6
-Triisobutylphenylcarbodiimide and the like. Furthermore, one or two or more compounds may be arbitrarily selected from these monocarbodiimide compounds to block the carboxyl terminal of polylactic acid. However, heat resistance and reactivity and affinity with polylactic acid may be improved. From the viewpoint, N, N'-di-2,6-diisopropylphenylcarbodiimide (hereinafter referred to as TIC) is preferable, and when two or more monocarbodiimide compounds are used in combination, the total amount of the monocarbodiimide compounds used as the terminal blocking agent is It is preferable that 50% or more of them is TIC.
【００１８】モノカルボジイミド化合物によりカルボキ
シル基末端を封鎖する方法としては、ポリ乳酸の溶融状
態でモノカルボジイミド化合物を末端封鎖剤として適量
反応させることで得ることができるが、ポリ乳酸の高重
合度化、残存低分子量物の抑制などの観点から、ポリマ
ーの重合反応終了後にモノカルボジイミド化合物を添加
・反応させることが好ましい。上記したモノカルボジイ
ミド化合物とポリ乳酸との混合・反応としては、例え
ば、重縮合反応終了直後の溶融状態のポリ乳酸にモノカ
ルボジイミド化合物を添加し攪拌・反応させる方法、ポ
リ乳酸のチップにモノカルボジイミド化合物を添加・混
合した後に反応缶あるいはエクストルーダなどで混練・
反応させる方法、エクストルーダでポリ乳酸に液状のモ
ノカルボジイミド化合物を連続的に添加し、混練・反応
させる方法、モノカルボジイミド化合物を高濃度含有さ
せたポリ乳酸のマスターチップとポリ乳酸のホモチップ
とを混合したブレンドチップをエクストルーダなどで混
練・反応させる方法などにより行うことができる。As a method of blocking the carboxyl group terminal with a monocarbodiimide compound, it can be obtained by reacting an appropriate amount of the monocarbodiimide compound as a terminal blocking agent in a molten state of polylactic acid, and increasing the polymerization degree of polylactic acid, From the viewpoint of suppressing residual low molecular weight substances, it is preferable to add and react the monocarbodiimide compound after the polymerization reaction of the polymer is completed. As the mixing / reaction of the above-mentioned monocarbodiimide compound and polylactic acid, for example, a method of adding a monocarbodiimide compound to polylactic acid in a molten state immediately after the completion of the polycondensation reaction and stirring / reacting it, a monocarbodiimide compound on a chip of polylactic acid After adding and mixing, knead in a reaction can or extruder.
Method of reacting, method of continuously adding liquid monocarbodiimide compound to polylactic acid with extruder, kneading and reacting, polylactic acid master chip containing high concentration of monocarbodiimide compound and polylactic acid homochip were mixed It can be performed by a method of kneading and reacting the blended chips with an extruder or the like.
【００１９】モノカルボジイミド化合物とカルボキシル
基の反応は付加反応であることから、例えば、アルコー
ルとカルボキシル基の脱水縮合反応による末端封鎖のよ
うに余分な副生成物を反応系外に排出する必要がない。
そのため、例えば上述したように溶融成形時にモノカル
ボジイミド化合物を添加・混合・反応させることによ
り、最適な条件でのポリマー重合と成形時のカルボキシ
ル基末端生成の抑制による十分な末端封鎖を両立するこ
とができ、実用的に十分な高い分子量や耐熱性および耐
加水分解性を兼ね備えた、従来にないポリ乳酸樹脂や繊
維およびフィルム等の成形物を得るとことが可能であ
る。Since the reaction between the monocarbodiimide compound and the carboxyl group is an addition reaction, it is not necessary to discharge an extra by-product to the outside of the reaction system, as in the case of end-capping due to dehydration condensation reaction of alcohol and carboxyl group. .
Therefore, for example, as described above, by adding, mixing, and reacting the monocarbodiimide compound during melt molding, it is possible to achieve both polymer polymerization under optimal conditions and sufficient terminal blocking by suppressing carboxyl group terminal generation during molding. It is possible to obtain molded articles such as polylactic acid resins and fibers and films which have not been heretofore and have a practically sufficiently high molecular weight, heat resistance and hydrolysis resistance.
【００２０】本発明のポリ乳酸では、用途に応じて適度
にカルボキシル末端基の封鎖を行えばよいが、具体的な
カルボキシル基末端封鎖の程度としてはポリ乳酸のカル
ボキシル基末端の濃度が１０当量／１０3ｋｇ以下であ
ることが耐加水分解性の点から好ましく、６当量／１０
3ｋｇ以下であることがさらに好ましい。ここでカルボ
キシル基末端の濃度とは実施例中に記載の方法によって
測定した値を指す。カルボキシル基末端はすべてが封鎖
されていてもよい。In the polylactic acid of the present invention, the carboxyl terminal group may be appropriately blocked according to the use, but as a concrete degree of the carboxyl group terminal blocking, the concentration of the carboxyl group terminal of polylactic acid is 10 equivalent / From the viewpoint of hydrolysis resistance, it is preferably 10 3 kg or less, and 6 equivalent / 10
More preferably, it is 3 kg or less. Here, the concentration of the terminal carboxyl group refers to a value measured by the method described in the examples. All of the carboxyl group terminals may be blocked.
【００２１】また、さらに持続性のある耐加水分解性を
付与する観点から、本発明のポリ乳酸樹脂に加えて、モ
ノカルボジイミド化合物などの付加反応型の末端封鎖剤
を未反応状態で含有させたポリ乳酸樹脂組成物とするこ
とが好ましい。さらに、本発明のポリ乳酸樹脂はＴ5%が
１７０℃以上のモノカルボジイミド化合物によりカルボ
キシル基末端が封鎖されていることを特徴とするもので
あることから、ポリ乳酸樹脂の押出し成形時において、
原料となるポリ乳酸のカルボキシル基末端を封鎖するた
めに必要となる重量以上のＴ5%が１７０℃以上であるモ
ノカルボジイミド化合物を溶融したポリマーに添加し、
混練・反応させると工業的に有利である。未反応で含有
させる末端封鎖剤としては、ポリ乳酸中における安定性
や耐熱性の観点からＴＩＣが好ましい。また、未反応末
端封鎖剤の含有量としては、成形品の耐熱性や外観、あ
るいは繊維やフィルムとして用いる場合に実用的な機械
的強度とする観点から、５．０重量％以下含有すること
が好ましく、２．０重量％以下含有することがさらに好
ましい。From the viewpoint of imparting more durable hydrolysis resistance, in addition to the polylactic acid resin of the present invention, an addition reaction type end-blocking agent such as a monocarbodiimide compound is contained in an unreacted state. It is preferable to use a polylactic acid resin composition. Further, the polylactic acid resin of the present invention is characterized in that the carboxyl group terminal is blocked by a monocarbodiimide compound having T 5% of 170 ° C. or higher. Therefore, during extrusion molding of the polylactic acid resin,
A monocarbodiimide compound having T 5% of 170 ° C. or more, which is more than the weight necessary to block the carboxyl end of polylactic acid as a raw material, is added to the molten polymer,
It is industrially advantageous to knead and react. As the terminal blocking agent to be contained unreacted, TIC is preferable from the viewpoint of stability in polylactic acid and heat resistance. In addition, the content of the unreacted end-blocking agent is 5.0 wt% or less from the viewpoint of heat resistance and appearance of the molded product or practical mechanical strength when used as a fiber or film. It is preferable that the content is 2.0 wt% or less.
【００２２】本発明のポリ乳酸樹脂は、溶融・溶液状態
から繊維・フィルム、シート、また各種成形品に成形加
工することが可能であり、実用的に十分な高い分子量や
耐熱性および耐加水分解性を兼ね備えていることで、従
来以上に広い分野での利用が可能である。例えば、繊維
分野では衣料用途、漁網、海苔網、植生保護用不織布、
土木用ネット、土嚢、育苗用ポット、農業用資材、水切
り袋など、フィルムやシートでは包装用フィルム、農園
芸用フィルム、ショッピングバック、ごみ袋、堆肥袋な
ど、その他の成形品では飲料や化粧品のボトル、ディス
ポーザブルカップ、トレイ、ナイフ、フォーク、スプー
ンなどの容器・食器類、植木鉢、育苗床などが挙げら
る。The polylactic acid resin of the present invention can be processed into fibers, films, sheets and various molded products from a molten or solution state, and has a practically sufficiently high molecular weight, heat resistance and hydrolysis resistance. By having both properties, it can be used in a wider field than before. For example, in the field of textiles, clothing applications, fishing nets, seaweed nets, vegetation protection non-woven fabrics,
Civil engineering nets, sandbags, pots for raising seedlings, agricultural materials, draining bags, etc.For films and sheets, packaging films, agricultural and horticultural films, shopping bags, garbage bags, compost bags, and other molded products such as beverages and cosmetics. Examples include containers and tableware such as bottles, disposable cups, trays, knives, forks and spoons, flowerpots, nurseries.
【００２３】本発明のポリ乳酸樹脂は、上述した形態の
なかでも体積比表面積が大きく実用に共されたとき十分
な耐加水分解性が求められる繊維およびフィルム分野に
おいて特に有効である。例えば、繊維として使用する場
合では、染料の水分散溶液による高温での染色が可能と
なり布帛の引裂強度を損なうことなく濃色あるは鮮明な
色合いに染めることができる。また、漁網などの水産資
材用として水中で使用する場合にはカルボキシル基末端
の封鎖を適度に行うことによりその使用期間中は実用的
に必要十分な強度が発揮される繊維を得ることができ
る。さらには経時安定性に富んでおり製造後長期間経た
後でも劣化することもなく当初の性能を発揮する繊維を
得ることができる。また、繊維やフィルム関連で種々の
乾熱加工時や高温雰囲気中での使用においても、安定し
た強度物性や耐久性を発揮する繊維やフィルムを得るこ
とができる。Among the above-mentioned forms, the polylactic acid resin of the present invention has a large volume specific surface area and is particularly effective in the field of fibers and films where sufficient hydrolysis resistance is required when it is put into practical use. For example, when it is used as a fiber, it can be dyed at a high temperature with an aqueous dispersion solution of a dye, and can be dyed in a dark or vivid shade without impairing the tear strength of the cloth. Further, when used in water for fisheries materials such as fishing nets, by appropriately blocking the end of the carboxyl group, it is possible to obtain a fiber that exhibits practically necessary and sufficient strength during the period of use. Further, it is highly stable over time, and it is possible to obtain a fiber that exhibits the initial performance without deterioration even after a long period of time after production. In addition, it is possible to obtain a fiber or film which exhibits stable strength properties and durability even during various dry heat processings or use in a high temperature atmosphere in relation to the fiber or film.
【００２４】なお、本発明のポリ乳酸樹脂から成る繊維
としては、マルチフィラメント、ステープルファイバ
ー、トウ、スパンボンドなどとして用いることができ
る。特にマルチフィラメントとして用いる場合は、実用
的な観点から強度が３．０ｃＮ／ｄｔｅｘ以上、さらに
は４．０ｃＮ／ｄｔｅｘ以上であることが好ましい。ま
た、毛羽や糸切れの少ない工業的な製糸工程により糸を
得るという観点から、９．０ｃＮ／ｄｔｅｘ以下が好ま
しい。The fibers made of the polylactic acid resin of the present invention can be used as multifilaments, staple fibers, tows, spunbonds and the like. Particularly when used as a multifilament, the strength is preferably 3.0 cN / dtex or more, and more preferably 4.0 cN / dtex or more from a practical viewpoint. Further, from the viewpoint of obtaining a yarn by an industrial yarn making process with less fluff and yarn breakage, it is preferably 9.0 cN / dtex or less.
【００２５】また、本発明のポリ乳酸樹脂から成る繊維
の単繊維繊度は使用形態や、機械的強度、生分解速度な
どの要求特性に応じて選択すればよいが、通常０．５ｄ
ｔｅｘ以上、１１１１１ｄｔｅｘ以下である。また、マ
ルチフィラメントとしての総繊度では３３ｄｔｅｘ以
上、１１１１１ｄｔｅｘ以下とすることが好ましい。さ
らに、断面形状は、丸、扁平、中空、Ｙ型、Ｔ型、多角
形など任意であるが、製糸性の観点から丸断面が好まし
い。The monofilament fineness of the fiber made of the polylactic acid resin of the present invention may be selected according to the required characteristics such as use form, mechanical strength and biodegradation rate, but is usually 0.5d.
It is tex or more and 11111 dtex or less. The total fineness of the multifilament is preferably 33 dtex or more and 11111 dtex or less. Further, the cross-sectional shape is arbitrary such as round, flat, hollow, Y-shaped, T-shaped, polygonal, etc., but a round cross-section is preferable from the viewpoint of yarn formability.
【００２６】本発明のポリ乳酸樹脂から成るフィルムの
厚さは特に制限はなく、用途に応じて要求される性能、
例えば、機械的強度、生分解速度、価格などにより適宜
な厚さにすればよいが、通常５μｍ以上、１ｍｍ以下で
あり、特に１０μｍ以上、２００μｍ以下の範囲が好ん
で選択される。また、実用的な観点から、縦方向と横方
向の引張弾性率（ヤング率）の平均値が、１ＧＰａ以
上、さらには、２ＧＰａ以上であることが好ましく、縦
方向と横方向の引張強度の平均値が５０ＭＰａ以上、さ
らには１００ＭＰａ以上であることが好ましい。また、
製膜時のフィルム破れを抑制し工業的に生産する観点か
らは、引張弾性率の平均値が１０ＧＰａ以下、引張強度
の平均値が１ＧＰａ以下であることが好ましい。The thickness of the film made of the polylactic acid resin of the present invention is not particularly limited, and the performance required depending on the application,
For example, the thickness may be appropriately set depending on the mechanical strength, biodegradation rate, price, etc., but is usually 5 μm or more and 1 mm or less, and particularly preferably 10 μm or more and 200 μm or less. From a practical point of view, the average value of the tensile elastic modulus (Young's modulus) in the longitudinal direction and the transverse direction is preferably 1 GPa or more, more preferably 2 GPa or more, and the average tensile strength in the longitudinal direction and the transverse direction. The value is preferably 50 MPa or more, and more preferably 100 MPa or more. Also,
From the viewpoint of suppressing film breakage during film formation and industrially producing the film, it is preferable that the average tensile elastic modulus is 10 GPa or less and the average tensile strength is 1 GPa or less.
【００２７】さらに、本発明のポリ乳酸樹脂から成るフ
ィルムは、印刷性、ラミネート適性、コーティング適性
などを向上させる目的で各種の表面処理を施しても良
い。表面処理の方法としては、コロナ放電処理、プラズ
マ処理、火炎処理、酸処理などが挙げられ、いずれの方
法をも用いることができが、連続処理が可能であり、既
存の製膜設備への装置設置が容易な点や処理の簡便さか
らコロナ放電処理が最も好ましいものとして例示でき
る。Further, the film made of the polylactic acid resin of the present invention may be subjected to various surface treatments for the purpose of improving printability, laminating suitability, coating suitability and the like. Examples of the surface treatment method include corona discharge treatment, plasma treatment, flame treatment, and acid treatment, and any of the methods can be used, but continuous treatment is possible, and an apparatus for existing film forming equipment is used. Corona discharge treatment can be exemplified as the most preferable one because it is easy to install and the treatment is simple.
【００２８】[0028]
【実施例】以下、実施例により本発明を詳細に説明す
る。なお、実施例中の物性は次の方法で測定した値であ
る。The present invention will be described in detail below with reference to examples. The physical properties in the examples are values measured by the following methods.
【００２９】５％重量減少温度Ｔ5%（℃）：ＭＡＣ Ｓ
ＣＩＥＮＣＥ社製“ＴＧ−ＤＴＡ２０００Ｓ”ＴＧ−Ｄ
ＴＡ測定機により、試料重量１０ｍｇ程度、窒素雰囲気
中にて昇温速度１０℃／分として測定した時の、測定開
始前の試料重量に対して重量が５％減量したときの温度
として求めた。5% weight loss temperature T 5% (° C.): MAC S
CIENCE "TG-DTA2000S" TG-D
It was determined as a temperature when the weight of the sample was reduced by 5% with respect to the sample weight before the start of measurement when measured with a TA measuring machine at a sample weight of about 10 mg and a heating rate of 10 ° C./min in a nitrogen atmosphere.
【００３０】カルボキシル基末端濃度（当量／１０3ｋ
ｇ）：精秤した試料をｏ−クレゾール（水分５％）調整
液に溶解し、この溶液にジクロロメタンを適量添加の
後、０．０２規定のＫＯＨメタノール溶液にて滴定する
ことにより測定した。Carboxyl group terminal concentration (equivalent / 10 3 k)
g): The precisely weighed sample was dissolved in an o-cresol (water content: 5%) adjusting solution, and an appropriate amount of dichloromethane was added to this solution, followed by titration with a 0.02N KOH methanol solution.
【００３１】溶液比粘度（以下、ηｒと示す。）：オル
ソクロルフェノール１００ｍｌに対し重合体の試料３ｇ
を溶解した溶液を２５℃としてオストワルド式粘度計に
て測定した。Specific viscosity of solution (hereinafter referred to as ηr): 3 g of polymer sample per 100 ml of orthochlorophenol
The solution in which was dissolved was set to 25 ° C. and measured with an Ostwald viscometer.
【００３２】粘度保持率（％）：熱水処理後試料の溶液
比粘度の、熱水処理前の溶液比粘度に対する割合として
算出した。Viscosity retention (%): Calculated as the ratio of the solution specific viscosity of the sample after hot water treatment to the solution specific viscosity before hot water treatment.
【００３３】糸強度（ｃＮ／ｄｔｅｘ）：（株）オリエ
ンテック社製“テンシロン”引張試験機を用い、試料長
２５ｃｍ、引張速度３０ｃｍ／分の条件で測定した。Yarn Strength (cN / dtex): Measured using a "Tensilon" tensile tester manufactured by Orientec Co., Ltd. under the conditions of a sample length of 25 cm and a tensile speed of 30 cm / min.
【００３４】フィルム強度（ＭＰａ）：（株）東洋精機
社製“テンシロンII型機”引張試験機を用い、ＪＩＳ
Ｋ７１２７に基づき、引張り速度を１００ｍｍ／分とし
て測定した。Film Strength (MPa): JIS Tenshiron II type tensile tester manufactured by Toyo Seiki Co., Ltd.
Based on K7127, the tensile speed was measured at 100 mm / min.
【００３５】強度保持率（％）：熱水処理後試料の強度
の、熱水処理前の強度に対する割合として算出した。Strength retention (%): Calculated as the ratio of the strength of the sample after hot water treatment to the strength before hot water treatment.
【００３６】また、耐加水分解性の加速試験として、チ
ップ、および糸やフィルムなどのサンプル３０ｇと水３
００ｍｌを密閉可能な容器に入れた後、容器内の水温が
１３０℃となるように加熱して所定の時間保持した後に
冷却・水洗を行って熱水処理後の試料を作製し、これを
評価した。As an accelerated hydrolysis resistance test, 30 g of chips such as chips and threads and films and 3 parts of water were used.
After placing 00 ml in a container that can be sealed, heat the water in the container to 130 ° C and hold for a specified time, then cool and wash to prepare a sample after hot water treatment, and evaluate this. did.
【００３７】（実施例１）
Ｌ−ラクチドに対しオクチル酸錫を１５０ｐｐｍ混合
し、撹拌装置付きの反応容器中で窒素雰囲気中１９２℃
で１０分間重合し、さらに２軸混練押出し機にてチップ
化後、１４５℃の窒素雰囲気中で固相重合して、融点１
７６℃のポリＬ−乳酸（以下、ＰＬＬＡという。）チッ
プを得た。さらに、このＰＬＬＡチップを１００℃で１
２時間減圧乾燥した後、ＰＬＬＡ：Ｎ，Ｎ´−ジ−２，
６−ジイソプロピルフェニルカルボジイミド＝９９．２
８：０．７２（重量部）となるように加熱溶融したＮ，
Ｎ´−ジ−２，６−ジイソプロピルフェニルカルボジイ
ミド（バイエル社製品“スタバクゾール”（登録商標）
Ｉ。以下、ＴＩＣという。）を計量して連続的にＰＬＬ
Ａチップに添加しながらシリンダー温度２２０℃の２軸
混練押出し機に供することで両者を反応させ、ηｒが
９．０８のカルボキシル末端が封鎖されたＰＬＬＡチッ
プを得た。Example 1 150 ppm of tin octylate was mixed with L-lactide, and the mixture was stirred at 192 ° C. in a nitrogen atmosphere in a reaction vessel equipped with a stirrer.
Polymerization for 10 minutes, chipping with a twin-screw kneading extruder, solid phase polymerization in a nitrogen atmosphere at 145 ° C., melting point 1
A 76 ° C. poly-L-lactic acid (hereinafter referred to as PLLA) chip was obtained. Furthermore, this PLLA chip is
After drying under reduced pressure for 2 hours, PLLA: N, N'-di-2,
6-diisopropylphenylcarbodiimide = 99.2
8: 0.72 (parts by weight) heated and melted N,
N'-di-2,6-diisopropylphenylcarbodiimide ("Starvacsol" (registered trademark) manufactured by Bayer Co.)
I. Hereinafter referred to as TIC. ) Is measured and PLL is continuously
While being added to the A chip, the two were reacted by being subjected to a twin-screw kneading extruder having a cylinder temperature of 220 ° C. to obtain a PLLA chip in which ηr was 9.08 and the carboxyl terminal was blocked.
【００３８】評価結果を表１に示す。The evaluation results are shown in Table 1.
【００３９】（実施例２）
ＤＬ−ラクチドを混合した後に重合して融点１５５℃、
重量平均分子量１１．５万のＤ体共重合率５ｍｏｌ％ポ
リＬ−乳酸共重合体を得て、さらにポリＬ−乳酸共重合
体：ＴＩＣ＝９８．７２：１．２８（重量部）となるよ
うに計量したたこと以外は実施例１と同様にしてηｒが
７．６６のカルボキシル末端が封鎖されたポリＬ−乳酸
共重合体（以下、Ｐ（Ｌ／Ｄ）ＬＡという。）チップを
得た。評価結果を表１に示す。Example 2 DL-lactide was mixed and then polymerized to give a melting point of 155 ° C.
A poly-L-lactic acid copolymer having a weight average molecular weight of 115,000 and a D-form copolymerization rate of 5 mol% was obtained, and the poly-L-lactic acid copolymer: TIC = 98.72: 1.28 (parts by weight). A poly L-lactic acid copolymer (hereinafter referred to as P (L / D) LA) chip having a carboxy end blocked with ηr of 7.66 was obtained in the same manner as in Example 1 except that the measurement was performed as described above. It was The evaluation results are shown in Table 1.
【００４０】（実施例３）
ＰＬＬＡ：ＴＩＣ＝９８．９１：１．０９（重量部）と
なるように計量した以外は実施例１と同様にしてηｒが
８．８９のカルボキシル末端が封鎖されたＰＬＬＡチッ
プを得た。Example 3 The carboxyl terminal having ηr of 8.89 was blocked in the same manner as in Example 1 except that PLLA: TIC = 98.91: 1.09 (parts by weight) was weighed. A PLLA chip was obtained.
【００４１】評価結果を表１に示す。The evaluation results are shown in Table 1.
【００４２】（実施例４）
ＰＬＬＡ：ＴＩＣ＝９６．７０：３．３０（重量部）と
なるように計量した以外は実施例１と同様にしてηｒが
８．８２のカルボキシル末端が封鎖されたＰＬＬＡチッ
プを得た。Example 4 The carboxyl terminal having ηr of 8.82 was blocked in the same manner as in Example 1 except that PLLA: TIC = 96.70: 3.30 (parts by weight) was weighed. A PLLA chip was obtained.
【００４３】評価結果を表１に示す。The evaluation results are shown in Table 1.
【００４４】（比較例１）
ＰＬＬＡチップに末端封鎖剤を添加することなく再びシ
リンダー温度２２０℃の２軸混連押出し機に供したこと
以外は実施例１と同様にしてηｒが９．１２のカルボキ
シル末端が未封鎖のＰＬＬＡチップを得た。Comparative Example 1 ηr was 9.12 in the same manner as in Example 1 except that the PLLA chip was again subjected to a twin-screw mixed extruder having a cylinder temperature of 220 ° C. without adding an end-capping agent. A PLLA chip having an unblocked carboxyl terminal was obtained.
【００４５】評価結果を表１に示す。The evaluation results are shown in Table 1.
【００４６】（比較例２）
Ｌ−ラクチド：１−デカノール（以下、ＤｃＯＨとい
う。）＝９９．６９：０．３１（重量部）の混合物にオ
クチル酸錫を１５０ｐｐｍを添加した混合物をトルエン
溶液を撹拌装置付きの反応容器中で２時間減圧乾燥した
後、窒素雰囲気中１９２℃で１０分間重合し、さらに２
軸混練押出し機にてチップ化後、１４０℃の窒素雰囲気
中で固相重合して、融点１７２℃、重量平均分子量９．
６万のＰＬＬＡチップを得た。さらに、このＰＬＬＡチ
ップを１００℃で１２時間減圧乾燥した後、末端封鎖剤
を添加することなく再びシリンダー温度２２０℃の２軸
混練押出し機に供してηｒが７．４８のカルボキシル末
端が封鎖されたＰＬＬＡチップを得た。Comparative Example 2 A mixture of L-lactide: 1-decanol (hereinafter referred to as DcOH) = 99.69: 0.31 (parts by weight) to which 150 ppm of tin octylate was added was added to a toluene solution. After drying under reduced pressure in a reaction vessel equipped with a stirrer for 2 hours, polymerization was carried out at 192 ° C for 10 minutes in a nitrogen atmosphere, and further 2
After chipping with a shaft kneading extruder, solid phase polymerization was performed in a nitrogen atmosphere at 140 ° C., melting point 172 ° C., weight average molecular weight 9.
60,000 PLLA chips were obtained. Further, this PLLA chip was dried under reduced pressure at 100 ° C. for 12 hours, and then subjected to a twin-screw kneading extruder having a cylinder temperature of 220 ° C. again without adding a terminal blocking agent to block the carboxyl terminal having ηr of 7.48. A PLLA chip was obtained.
【００４７】評価結果を表１に示す。The evaluation results are shown in Table 1.
【００４８】（比較例３）
末端封鎖剤としてＮ，Ｎ´−ジシクロヘキシルカルボジ
イミド（以下、ＤＨＣという。）を使用し、ＰＬＬＡ：
ＤＨＣ＝９９．６０：０．４０（重量部）となるように
計量した以外は実施例１と同様にしてηｒが８．８２の
カルボキシル末端が封鎖されたＰＬＬＡチップを得た。
ただし、吐出部からの発煙がかなり激しく、添加したＤ
ＨＣが有効に反応していないことが伺われた。(Comparative Example 3) N, N'-dicyclohexylcarbodiimide (hereinafter referred to as DHC) was used as a terminal blocking agent, and PLLA:
A PLLA chip having a carboxylic acid terminal blocked with ηr of 8.82 was obtained in the same manner as in Example 1 except that the weight was adjusted to DHC = 99.60: 0.40 (parts by weight).
However, the smoke emitted from the discharge part was quite intense, and the added D
It was found that HC did not react effectively.
【００４９】評価結果を表１に示す。The evaluation results are shown in Table 1.
【００５０】（比較例４）
末端封鎖剤としてＤＨＣを使用し、ＰＬＬＡ：ＤＨＣ＝
９９．３４：０．６６（重量部）となるように計量した
以外は実施例１と同様にしてカルボキシル末端が封鎖さ
れたＰＬＬＡチップの作製を試みたが、吐出部からの発
煙およびガット内部の発泡が激しく、チップ化できなか
った。Comparative Example 4 DHC was used as a terminal blocking agent, and PLLA: DHC =
An attempt was made to produce a PLLA chip having a carboxyl terminal blocked, in the same manner as in Example 1 except that the amount was adjusted to 99.34: 0.66 (parts by weight). The foaming was so severe that it could not be made into chips.
【００５１】（比較例５）
グリコール酸７１％水溶液を撹拌装置付きの反応容器
中、減圧下において１８０℃で４時間濃縮、脱水し結晶
性の低重合体を得た。さらにこの低重合体を１８０℃で
５時間減圧乾燥した後、３００℃の窒素雰囲気中で熱分
解させて粗グリコリドを得、この粗グリコリドを原料と
して酢酸エチル溶液からの再結晶法により精製して精製
グリコリドとした。この精製グリコリドにオクチル酸錫
１００ｐｐｍとラウリルアルコール１００ｐｐｍを混合
し、撹拌装置付きの反応容器で窒素雰囲気中１８０℃で
３時間開環重合を行い２軸混練押出し機にてチップ化し
て、融点２２４℃のポリグリコール酸（以下、ＰＧＡと
いう。）チップを得た。）さらにこのＰＧＡチップを１
３０℃で１２時間減圧乾燥した後、ＰＧＡ：ＴＩＣ＝９
８．１９：１．８１（重量部）となるように加熱溶融し
た液状のＴＩＣを連続的にＰＧＡチップに添加しながら
シリンダー温度２７０℃の２軸混連押出し機に供するこ
とで両者を反応させ、ηｒが１．４７（トリクロロフェ
ノール／フェノール＝７／１０溶液を用い、濃度０．５
ｇ／１００ｍｌ、３０℃にて測定）のカルボキシル末端
が封鎖されたＰＧＡチップを得た。Comparative Example 5 A 71% aqueous solution of glycolic acid was concentrated and dehydrated at 180 ° C. for 4 hours under reduced pressure in a reaction vessel equipped with a stirrer to obtain a crystalline low polymer. Further, this low polymer was dried under reduced pressure at 180 ° C. for 5 hours, and then pyrolyzed in a nitrogen atmosphere at 300 ° C. to obtain crude glycolide, which was purified by a recrystallization method from an ethyl acetate solution using this crude glycolide as a raw material. The purified glycolide was used. 100 ppm of tin octylate and 100 ppm of lauryl alcohol were mixed with this purified glycolide, and ring-opening polymerization was carried out in a nitrogen atmosphere at 180 ° C. for 3 hours in a reaction vessel equipped with a stirrer to form chips with a biaxial kneading extruder, and a melting point of 224 ° C. A polyglycolic acid (hereinafter referred to as PGA) chip was obtained. ) Furthermore, this PGA chip 1
After drying under reduced pressure at 30 ° C. for 12 hours, PGA: TIC = 9
8.19: 1.81 (parts by weight) The liquid TIC which was heated and melted was continuously added to the PGA chips, and the mixture was subjected to a twin-screw extruder with a cylinder temperature of 270 ° C. to react them with each other. , Ηr 1.47 (using a solution of trichlorophenol / phenol = 7/10, concentration 0.5
g / 100 ml, measured at 30 ° C.) to obtain a PGA chip with the carboxyl terminal blocked.
【００５２】評価結果を表１に示す。The evaluation results are shown in Table 1.
【００５３】（比較例６）
ＰＧＡチップに末端封鎖剤を添加することなく再びシリ
ンダー温度２７０℃の２軸混練押出し機に供したこと以
外は比較例５と同様にしてηｒが１．４１（トリクロロ
フェノール／フェノール＝７／１０溶液を用い、濃度
０．５ｇ／１００ｍｌ、３０℃にて測定）のカルボキシ
ル末端が未封鎖のＰＧＡチップを得た。(Comparative Example 6) In the same manner as in Comparative Example 5 except that the PGA chip was again subjected to the twin-screw kneading extruder having a cylinder temperature of 270 ° C. without adding an end-capping agent, ηr was 1.41 (trichloromethane). Using a phenol / phenol = 7/10 solution, a concentration of 0.5 g / 100 ml was measured at 30 ° C.) to obtain a PGA chip with an unblocked carboxyl terminal.
【００５４】評価結果を表１に示す。The evaluation results are shown in Table 1.
【００５５】[0055]
【表１】 [Table 1]
【００５６】（実施例５）
実施例３のカルボキシル末端が封鎖されたＰＬＬＡチッ
プを１００℃で１２時間減圧乾燥した後、環状３列配孔
で０．６φの吐出孔を９６個持つ口金を用い、エクスト
ル−ダー型の溶融紡糸機にて紡糸温度２２０℃の条件に
て溶融紡糸し、口金から紡出直後長さ３００ｍｍ、温度
２６０℃の加熱筒内の雰囲気を通過させた後、環状チム
ニーを通過させて風速２０ｍ／分のチムニー風により冷
却し油剤を付与した後、１０００ｍ／分の速度で引取る
ことにより未延伸糸を一旦巻き取った。この未延伸糸を
１段目延伸温度８０℃、２段目延伸温度１４０℃、総延
伸倍率５．５倍にて２段延伸し、引き続いて温度１４５
℃において熱固定、０．５％の弛緩処理を施した後３２
０ｍ／分にて延伸糸を引き取った。このようにして５５
６ｄｔｅｘ／９６ｆｉｌ、強度５．０５ｃＮ／ｄｔｅ
ｘ、伸度２８％のカルボキシル末端が封鎖されたＰＬＬ
Ａからなる繊維を得た。Example 5 The PLLA chip of which the carboxyl terminal was blocked in Example 3 was dried under reduced pressure at 100 ° C. for 12 hours, and then a die having 96 discharge holes of 0.6φ with three circular rows was used. After melt-spinning with an extruder-type melt spinning machine under the conditions of a spinning temperature of 220 ° C. and passing through an atmosphere in a heating cylinder having a length of 300 mm immediately after spinning from a spinneret and a temperature of 260 ° C., a ring chimney is formed. After passing and cooling with a chimney wind of a wind speed of 20 m / min to apply an oil agent, the undrawn yarn was once wound by taking up at a speed of 1000 m / min. The undrawn yarn was drawn in two stages at a first stage drawing temperature of 80 ° C., a second stage drawing temperature of 140 ° C. and a total draw ratio of 5.5 times, and subsequently at a temperature of 145.
32 after heat-setting at 0.5 ℃ and relaxation treatment of 0.5%
The drawn yarn was taken out at 0 m / min. 55 in this way
6dtex / 96fil, strength 5.05cN / dte
x, PLL with a 28% elongation blocked at the carboxyl end
A fiber consisting of A was obtained.
【００５７】評価結果を表２に示す。The evaluation results are shown in Table 2.
【００５８】（実施例６）
比較例１のカルボキシル末端が未封鎖のＰＬＬＡチップ
を用い、ＰＬＬＡ：ＴＩＣ＝９８．５１：１．４９（重
量部）となるように１００℃に加熱・溶融したＴＩＣを
計量して連続的にＰＬＬＡチップに添加しながらエクス
トルーダー型の溶融紡糸機へ供して両者を反応させなが
ら溶融紡糸した以外は実施例５と同様にして５５６ｄｔ
ｅｘ／９６ｆｉｌ、強度５．２３ｃＮ／ｄｔｅｘ、伸度
３０％のカルボキシル末端が封鎖されたＰＬＬＡからな
る繊維を得た。Example 6 Using the PLLA chip in which the carboxyl terminal was not blocked in Comparative Example 1, TIC was heated and melted at 100 ° C. so that PLLA: TIC = 98.51: 1.49 (parts by weight). 556 dt in the same manner as in Example 5 except that the compound was measured and continuously added to a PLLA chip, and the mixture was supplied to an extruder-type melt spinning machine to cause both to react and melt-spun.
A fiber composed of PLLA having ex / 96 fil, strength of 5.23 cN / dtex and elongation of 30% and having a carboxyl terminal blocked was obtained.
【００５９】評価結果を表２に示す。The evaluation results are shown in Table 2.
【００６０】（比較例７）
比較例１のカルボキシル末端が未封鎖のＰＬＬＡチップ
を溶融紡糸した以外は実施例５と同様にして５５６ｄｔ
ｅｘ／９６ｆｉｌ、強度５．１１ｃＮ／ｄｔｅｘ、伸度
２８％のカルボキシル末端が未封鎖のＰＬＬＡからなる
繊維を得た。(Comparative Example 7) 556dt was carried out in the same manner as in Example 5 except that the PLLA chip of Comparative Example 1 in which the carboxyl terminal was not blocked was melt-spun.
A fiber having an ex / 96 fil, a strength of 5.11 cN / dtex, an elongation of 28% and a carboxyl terminal unsealed PLLA was obtained.
【００６１】評価結果を表２に示す。The evaluation results are shown in Table 2.
【００６２】[0062]
【表２】 [Table 2]
【００６３】（実施例７）
実施例３のカルボキシル末端が封鎖されたＰＬＬＡチッ
プを１００℃で１２時間減圧乾燥した後、２１０℃にお
いてＴダイが装着された押出し機を用いて溶融、押出し
し、キャスティングロールにて急冷して厚さ０．４ｍｍ
の未延伸フィルムを得た。この未延伸フィルムを７０℃
に加熱したした後、長さ方向にロール法によって１．２
倍延伸した後、８０℃に加熱してテンターを用いて２倍
延伸を行い、引き続き緊張下で１４０℃において２分間
熱処理し、常温の空気を用いて冷却して、平均厚み０．
２ｍｍ、縦横方向の平均引張り強度が１１０ＭＰａのカ
ルボキシル末端が封鎖されたＰＬＬＡからなる２軸延伸
フィルムを得た。(Example 7) The PLLA chip of which the carboxyl end was blocked in Example 3 was dried under reduced pressure at 100 ° C for 12 hours, and then melted and extruded at 210 ° C using an extruder equipped with a T-die. Quenched with a casting roll and 0.4mm thick
An unstretched film of was obtained. This unstretched film is 70 ° C
After heating to 1, roll length 1.2
After being double-stretched, it is heated to 80 ° C. and double-stretched by using a tenter, and subsequently heat-treated under tension at 140 ° C. for 2 minutes and cooled with air at room temperature to give an average thickness of 0.
A biaxially stretched film made of PLLA having a carboxyl terminal of 2 mm and an average tensile strength in the longitudinal and transverse directions of 110 MPa and having a blocked carboxyl end was obtained.
【００６４】評価結果を表３に示す。The evaluation results are shown in Table 3.
【００６５】（比較例８）
比較例１のカルボキシル末端が未封鎖のＰＬＬＡチップ
を用いた以外は実施例７と同様にして、平均厚み０．２
ｍｍ、縦横方向の平均引張り強度が１０４ＭＰａのカル
ボキシル末端が未封鎖のＰＬＬＡからなる２軸延伸フィ
ルムを得た。Comparative Example 8 An average thickness of 0.2 was obtained in the same manner as in Example 7 except that the PLLA chip of Comparative Example 1 in which the carboxyl terminal was not blocked was used.
A biaxially stretched film made of PLLA having an unsealed carboxyl terminal and having an average tensile strength of 104 MPa in the longitudinal and transverse directions was obtained.
【００６６】評価結果を表３に示す。Table 3 shows the evaluation results.
【００６７】[0067]
【表３】 [Table 3]
【００６８】[0068]
【発明の効果】本発明のポリ乳酸樹脂は、従来技術では
不可能だった実用的に十分な高い分子量と高い耐加水分
解性および耐熱性を兼ね備えており、特に繊維やフィル
ム分野において従来以上に幅広い利用が可能である。INDUSTRIAL APPLICABILITY The polylactic acid resin of the present invention has a practically sufficient high molecular weight and high hydrolysis resistance and heat resistance, which were impossible in the prior art. Widely applicable.
【００６９】さらに、本発明のポリ乳酸樹脂は、従来の
プラスチックに対して自然環境中での生物分解性が高
く、使用後は自然環境中で比較的容易に分解されるとい
う利点を有する。本発明のポリ乳酸樹脂は、産業界およ
びプラスチック廃棄物に係る環境問題の解決に寄与する
ところが非常に大きい。Further, the polylactic acid resin of the present invention has an advantage over conventional plastics in that it is highly biodegradable in a natural environment and can be relatively easily decomposed in a natural environment after use. The polylactic acid resin of the present invention greatly contributes to the solution of environmental problems related to industry and plastic waste.
【００７０】[0070]
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C08G 63/00 - 63/91 ─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. 7 , DB name) C08G 63/00-63/91
Claims (6)
カルボジイミド化合物によりポリ乳酸のカルボキシル基
末端のうち一部または実質的に全部が封鎖されているこ
とを特徴とするポリ乳酸樹脂。1. A polylactic acid resin, wherein a part or substantially all of the carboxyl group terminals of polylactic acid are blocked with a monocarbodiimide compound having a 5% weight loss temperature of 170 ° C. or higher.
ジ−２，６−ジイソプロピルフェニルカルボジイミドで
あることを特徴とする請求項１記載のポリ乳酸樹脂。2. The monocarbodiimide compound is N, N′-
The polylactic acid resin according to claim 1, which is di-2,6-diisopropylphenylcarbodiimide.
リ乳酸１０3ｋｇ以下であることを特徴とする請求項１
または２記載のポリ乳酸樹脂。3. A carboxyl group terminal concentration is 10 equivalents / polylactic acid 10 3 kg or less.
Alternatively, the polylactic acid resin described in 2.
リ乳酸樹脂からなる成形品。4. A molded article made of the polylactic acid resin according to claim 1.
品。5. A method according to claim 4 molded article according moldings are textiles.
成形品。 6. The molded article according to claim 4, which is a film.
Molding.
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| JP2000070098A JP3440915B2 (en) | 2000-03-14 | 2000-03-14 | Polylactic acid resin and molded products |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000070098A JP3440915B2 (en) | 2000-03-14 | 2000-03-14 | Polylactic acid resin and molded products |
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| JP3440915B2 true JP3440915B2 (en) | 2003-08-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000070098A Ceased JP3440915B2 (en) | 2000-03-14 | 2000-03-14 | Polylactic acid resin and molded products |
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| JP (1) | JP3440915B2 (en) |
Cited By (1)
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| JP2005350829A (en) * | 2004-06-14 | 2005-12-22 | Nippon Ester Co Ltd | Polylactic acid fiber having excellent hydrolytic resistance |
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