JP3350606B2 - Method for producing polylactic acid - Google Patents
Method for producing polylactic acidInfo
- Publication number
- JP3350606B2 JP3350606B2 JP02092895A JP2092895A JP3350606B2 JP 3350606 B2 JP3350606 B2 JP 3350606B2 JP 02092895 A JP02092895 A JP 02092895A JP 2092895 A JP2092895 A JP 2092895A JP 3350606 B2 JP3350606 B2 JP 3350606B2
- Authority
- JP
- Japan
- Prior art keywords
- polymerization
- polymer
- lactide
- phase polymerization
- alcohol
- 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.)
- Expired - Fee Related
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- Polyesters Or Polycarbonates (AREA)
- Biological Depolymerization Polymers (AREA)
- Artificial Filaments (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は、乳酸を主成分とする重
合体の製造方法に関する。The present invention relates to a method for producing a polymer containing lactic acid as a main component.
【0002】[0002]
【従来の技術】生分解性又は自然環境下で分解するポリ
マーが、環境保護の見地から注目されている。乳酸を主
成分とする重合体は、分解性、耐熱性、溶融成型性、強
度などに優れ、主たる原料である乳酸が農産物より得ら
れるので資源的にも有利で、最も優れた分解性ポリマー
の一つと期待されている。乳酸を主成分とするポリマー
は、乳酸及び/又はラクチドを主成分とする重合原料を
重合して得ることが出来る。乳酸を直接重合する方法
は、(1)高純度の乳酸が必要、(2)重合(縮合)中
に生成した水を除去するため高真空が必要、(3)反応
速度が遅く重合に長時間を要する、などの問題点があ
り、経済性や品質に問題がある。一方、乳酸の環状2量
体であるラクチドからの重合は、(1)原料ラクチド精
製が容易で高純度のものが得られる、(2)加熱溶融で
容易且つ早く開環重合する、(3)従ってポリマーの品
質も優れているという長所があり、工業的にも極めて有
利である。2. Description of the Related Art Polymers that are biodegradable or decompose in the natural environment are attracting attention from the viewpoint of environmental protection. Lactic acid-based polymer is excellent in degradability, heat resistance, melt moldability, strength, etc., and the main raw material lactic acid is obtained from agricultural products, so it is also advantageous in resources, and One is expected. The polymer containing lactic acid as a main component can be obtained by polymerizing a polymerization raw material containing lactic acid and / or lactide as a main component. The method of direct polymerization of lactic acid requires (1) high-purity lactic acid, (2) high vacuum is required to remove water generated during polymerization (condensation), (3) reaction speed is slow and polymerization takes a long time. And the like, and there is a problem in economy and quality. On the other hand, polymerization from lactide, which is a cyclic dimer of lactic acid, can be achieved by (1) raw material lactide can be easily purified and high purity can be obtained, (2) ring-opening polymerization can be easily and quickly performed by heating and melting, (3) Therefore, there is an advantage that the quality of the polymer is excellent, which is extremely advantageous industrially.
【0003】[0003]
【発明が解決しようとする課題】しかし、ラクチドの溶
融開環重合では、開環重合とその逆反応が平衡的に起こ
り、重合後に一定量のモノマー(ラクチド)が残存する
という問題がある。ポリマー中にラクチドが多く残存す
ると、成型時に浸出したり昇化して環境を汚染したり、
ポリマーの分解性を早めたり、耐熱性その他品質や物性
を劣化させるなどの問題がある。重合後のポリマーよ
り、残存ラクチドを除去するには、溶剤による抽出、真
空による除去などの方法があるが、工業的にも経済的に
も不利である。本発明の目的は、ラクチドを主成分とす
る重合原料から、残存モノマーの少ない重合体を効果的
に製造する新しい方法を提供するにある。However, in melt ring-opening polymerization of lactide, there is a problem that ring-opening polymerization and its reverse reaction occur in equilibrium, and a certain amount of monomer (lactide) remains after polymerization. If a large amount of lactide remains in the polymer, it will leach or rise during molding, polluting the environment,
There are problems such as speeding up the decomposability of the polymer and deteriorating heat resistance and other quality and physical properties. To remove residual lactide from the polymer after polymerization, there are methods such as extraction with a solvent and removal by vacuum, but these are industrially and economically disadvantageous. An object of the present invention is to provide a new method for effectively producing a polymer having a small amount of residual monomers from a polymerization raw material containing lactide as a main component.
【0004】[0004]
【課題を解決するための手段及び作用】本発明方法は、
L−ラクチド及び/又はD−ラクチドを主成分とする重
合原料を溶融重合し(以下第1工程と言う)、次いで重
合したポリマーの冷却固化とチップ化をし(以下第2工
程と言う)、更に該チップの固相重合を行う(以下第3
工程と言う)際に、この固相重合工程の初期に該チップ
中に、重合系に対し0.1〜3重量%のアルコール又は
ラクトンを存在せしめる事を特徴とする。The method of the present invention comprises:
A polymerization raw material containing L-lactide and / or D-lactide as a main component is melt-polymerized (hereinafter, referred to as a first step), and then the polymerized polymer is cooled and solidified into chips (hereinafter, referred to as a second step), Further, solid-phase polymerization of the chip is carried out (hereinafter referred to as “third polymerization”).
In this case, 0.1 to 3% by weight of alcohol or lactone with respect to the polymerization system is present in the chip at the beginning of the solid phase polymerization step.
【0005】本発明において、L−及び/又はD−ラク
チドを主成分とする重合原料とは、L−及び/又はD−
ラクチドを50重量%以上含有する重合原料である。同
様に、乳酸を主成分とする重合体とは、重合体の構成成
分の50重量%以上がL及び/又はD−乳酸成分(セグ
メント)に由来するもので、L−乳酸ホモポリマー、D
−乳酸ホモポリマー、L/D−乳酸共重合体及びそれら
にエステル結合形成性の重合原料を50重量%以下共重
合したもの及び他の成分を50重量%以下混合したもの
を包含する。[0005] In the present invention, the polymerization raw material containing L- and / or D-lactide as a main component is L- and / or D-lactide.
It is a polymerization raw material containing 50% by weight or more of lactide. Similarly, a polymer containing lactic acid as a main component means that 50% by weight or more of the constituent components of the polymer are derived from L and / or D-lactic acid components (segments).
-Lactic acid homopolymers, L / D-lactic acid copolymers, and those obtained by copolymerizing 50% by weight or less of an ester bond-forming polymerization raw material and those obtained by mixing other components at 50% by weight or less.
【0006】本発明の第1工程の溶融重合は、L及び/
又はD−ラクチドを主成分とし、必要に応じ重合触媒、
他の共重合成分、安定剤、添加剤、着色剤などを加えた
重合原料を、得られる重合体の融点(例えばL−乳酸ホ
モポリマーでは約170℃)以上に加熱溶融し、必要に
応じて攪拌や不活性気体の供給と排出、真空などの操作
を行なうことにより容易に行なうことが出来る。例え
ば、重合原料をあらかじめ混合して、効果的に反応出来
る装置、例えば2軸混練機(重合機)に供給してもよ
く、重合原料を別々に2軸混練機に供給し、その内部で
攪拌、混合しつつ反応させてもよい。重合温度は、例え
ば180〜230℃、特に190〜220℃が好まし
く、重合時間は3分間〜2時間、特に5分間〜60分間
が好ましい。得られた重合体の重量平均分子量は5万以
上、特に8万〜30万が好ましい。[0006] The melt polymerization in the first step of the present invention comprises L and / or
Or D-lactide as a main component, if necessary, a polymerization catalyst,
A polymerization raw material to which other copolymer components, stabilizers, additives, coloring agents, and the like are added is heated and melted at a temperature not lower than the melting point of the obtained polymer (for example, about 170 ° C. for an L-lactic acid homopolymer). It can be easily performed by performing operations such as stirring, supply and discharge of an inert gas, and vacuum. For example, the polymerization raw materials may be mixed in advance and supplied to a device capable of effectively reacting, for example, a twin-screw kneader (polymerization machine), or the polymerization raw materials may be separately supplied to the twin-screw kneader and stirred therein. The reaction may be carried out while mixing. The polymerization temperature is, for example, preferably from 180 to 230 ° C, particularly preferably from 190 to 220 ° C, and the polymerization time is preferably from 3 minutes to 2 hours, particularly preferably from 5 minutes to 60 minutes. The weight average molecular weight of the obtained polymer is preferably 50,000 or more, particularly preferably 80,000 to 300,000.
【0007】本発明の第1工程に供給する重合原料の組
成は、L−ラクチド及び/又はD−ラクチドが50重量
%以上であるが、必要により加える共重合成分及び混合
成分、添加物などを50重量%以下の範囲で自由に選ぶ
ことが出来る。一般に共重合によって、乳酸を主成分と
する重合体は結晶性や融点が低下し、柔軟性や靱性が改
良され、分解性が増大する傾向がある。共重合原料とし
ては、エステル結合形成性の官能基を持つジカルボン
酸、ジオール、ヒドロキシカルボン酸、ラクトンなどが
あげられるが、高重合度の共重合物を得るには、分子量
の大きいもの、例えば末端に水酸基やカルボキシル基を
持つ脂肪族ポリエステル、融点180℃以下の芳香族成
分を含むポリエステル、ポリエーテルなどのポリマー及
びそれらのオリゴマーが好ましい。共重合成分として好
ましい脂肪族ポリマーとしては、ポリエチレンアジペー
ト、ポリヘキサメチレンアジペート、ポリカプロラクト
ン、ポリグリコール酸、ポリヒドロキシブチレートなど
があげられ、芳香族成分を含むポリエステルとしてはア
ルキレンテレフタレートやアルキレンイソフタレート又
はアルキレンスルホイソフタレートなどと脂肪族ポリエ
ステルとの共重合体などがあげられ、ポリエーテルとし
てはポリエチレングリコール、ポリプロピレングリコー
ル、ポリテトラメチレングリコール及びそれらの共重合
体などがあげられる。上記目的での共重合率や第3成分
の混合率は、多くの場合0.5〜50%、特に1〜30
%、最も多くの場合2〜20%が好ましい。[0007] The composition of the polymerization raw material supplied to the first step of the present invention is such that L-lactide and / or D-lactide is 50% by weight or more. It can be freely selected within a range of 50% by weight or less. In general, a copolymer containing lactic acid as a main component tends to have reduced crystallinity and melting point, improved flexibility and toughness, and increased degradability due to copolymerization. Examples of the copolymer raw material include dicarboxylic acids having a functional group capable of forming an ester bond, diols, hydroxycarboxylic acids, and lactones.To obtain a copolymer having a high degree of polymerization, those having a large molecular weight, such as a terminal Polymers such as aliphatic polyesters having a hydroxyl group or a carboxyl group, polyesters containing an aromatic component having a melting point of 180 ° C. or lower, polyethers, and oligomers thereof are preferred. Preferred aliphatic polymers as the copolymer component include polyethylene adipate, polyhexamethylene adipate, polycaprolactone, polyglycolic acid, polyhydroxybutyrate, and the like.As the polyester containing an aromatic component, alkylene terephthalate or alkylene isophthalate or Copolymers of an aliphatic polyester with alkylene sulfoisophthalate and the like can be mentioned. Polyethers include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and copolymers thereof. The copolymerization ratio and the mixing ratio of the third component for the above purpose are often 0.5 to 50%, particularly 1 to 30%.
%, Most often from 2 to 20%.
【0008】第3工程固相重合の初期に、重合系内に存
在すべきアルコール又は/及びラクトンは、第1工程の
末期に重合系に添加することが出来る。例えば2軸混練
機の出口近くに設けたベント孔や、供給孔から系内に供
給してもよく、押出口金の直前で系に注入し、例えば静
止混合器で混合しつつ押出してもよい。アルコール又は
ラクトンの添加率は残存モノマーに対し1〜30重量
%、特に3〜10重量%が好ましい。第1工程での20
0℃前後の重合時の残存モノマー(平衡値)は、10重
量%程度であるから、アルコール又はラクトンの添加率
は、重合系全体に対して、0.1〜3重量%、特に0.
3〜1重量%程度が好ましい。Third step At the beginning of the solid phase polymerization, the alcohol and / or lactone to be present in the polymerization system can be added to the polymerization system at the end of the first step. For example, the mixture may be supplied into the system from a vent hole or a supply hole provided near the outlet of the twin-screw kneader, or may be injected into the system immediately before the extrusion die, and extruded while being mixed with, for example, a static mixer. . The addition rate of the alcohol or lactone is preferably 1 to 30% by weight, particularly preferably 3 to 10% by weight, based on the residual monomer. 20 in the first step
The residual monomer (equilibrium value) at the time of polymerization at about 0 ° C. is about 10% by weight.
About 3 to 1% by weight is preferable.
【0009】固相重合初期に存在せしめるアルコール又
は/及びラクトンは、重合体(チップ)中に残存するラ
クチドの重合開始剤として働くものである。固相重合
は、ラクチドの融点(98℃)と重合体の融点との間の
温度、すなわち100〜170℃の範囲で行なうことが
好ましいから、添加するアルコール及びラクトンの沸点
(大気圧下)は、100℃以上、特に120℃以上が好
ましく、170℃以上が最も好ましい。アルコールとし
てはモノアルコール、グリコール、多価アルコール、末
端に水酸基を持つオリゴマー又はポリマーなどがあげら
れ、例えばブタノール、ヘキサノール、オクタノール、
デカノール、ラウリルアルコール、ステアリルアルコー
ルなどの脂肪族アルコール、シクロヘキサノールなどの
脂環族アルコール、グリコール酸、乳酸、ヒドロキシブ
チルカルボン酸などのヒドロキシカルボン酸、ヒドロキ
シ安息香酸、フェノールやビスフェノールにエチレンオ
キシドを付加反応させたものなどの芳香族アルコール、
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、ヘキサンジオール、オクタンジオール、グリセ
リン、ソルビタン、トリメチロールプロパン、ネオペン
チルグリコールなどの多価アルコール、ジエチレングリ
コール、トリエチレングリコール、ポリエチレングリコ
ール、ポリプロピレングリコールなどのエーテルグリコ
ールなどがあげられる。同じく固相重合時に存在せしめ
るラクトンとしては、グリコリド、ε−カプロラクト
ン、β−プロピオラクトン、βまたはγ−ブチロラクト
ン、ピバロラクトンなどがあげられる。これらのラクト
ンは、重合系に存在する微量の水分で開環してヒドロキ
シカルボン酸となり重合開始剤として働くと考えられ
る。The alcohol and / or lactone present at the early stage of solid phase polymerization functions as a polymerization initiator for lactide remaining in the polymer (chip). Since the solid-phase polymerization is preferably performed at a temperature between the melting point of lactide (98 ° C.) and the melting point of the polymer, that is, in the range of 100 to 170 ° C., the boiling points (atmospheric pressure) of the alcohol and lactone to be added are , 100 ° C or higher, particularly preferably 120 ° C or higher, and most preferably 170 ° C or higher. Examples of the alcohol include monoalcohols, glycols, polyhydric alcohols, oligomers and polymers having a hydroxyl group at a terminal, and the like, for example, butanol, hexanol, octanol,
Addition of ethylene oxide to aliphatic alcohols such as decanol, lauryl alcohol and stearyl alcohol, alicyclic alcohols such as cyclohexanol, hydroxycarboxylic acids such as glycolic acid, lactic acid and hydroxybutyl carboxylic acid, hydroxybenzoic acid, phenol and bisphenol Aromatic alcohols, such as
Polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, glycerin, sorbitan, trimethylolpropane, and neopentyl glycol; and ether glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, and polypropylene glycol. Can be Similarly, examples of the lactone to be present during the solid phase polymerization include glycolide, ε-caprolactone, β-propiolactone, β or γ-butyrolactone, and pivalolactone. It is considered that these lactones are ring-opened by a very small amount of water present in the polymerization system to become a hydroxycarboxylic acid and function as a polymerization initiator.
【0010】第3工程の重合開始剤であるアルコール及
び/又はラクトンは、第2工程及び/又は第3工程の初
期にチップに対して例えば噴霧などの方法で付着させ、
内部に浸透、拡散させることも出来る。The alcohol and / or lactone which is the polymerization initiator of the third step is attached to the chip at the beginning of the second and / or third step by, for example, spraying or the like,
It can also penetrate and diffuse inside.
【0011】第1工程の溶融重合を終えると、重合物は
冷却固化し、チップ(ペレット)化する。重合物は例え
ば、幅0.1〜2mmのスリットや直径2〜5mmの孔より
押出し、冷却固化し、切断してチップとする。冷却は水
冷も可能だが、後で乾燥する必要が生じ、しかも完全な
脱水が極めて困難であり、水を含んだ状態で加熱したり
再溶融すると、ポリマーは容易に加水分解し分子量が著
しく低下するなどの問題がある。従って、冷却は非水系
で行うことが好ましい。例えば押出したガット状、又は
シート状のポリマーを内部から冷却した金属ロールに1
回〜複数回接触して冷却固化し、カッターで切断する方
法が好ましい。この場合、雰囲気は水分を除いた空気、
又は窒素などの不活性気体が好ましい。After the completion of the melt polymerization in the first step, the polymer is cooled and solidified to form chips (pellets). The polymer is extruded through, for example, a slit having a width of 0.1 to 2 mm or a hole having a diameter of 2 to 5 mm, cooled and solidified, and cut into chips. Water can be used for cooling, but it is necessary to dry later, and it is extremely difficult to completely dehydrate.When heated or re-melted with water, the polymer is easily hydrolyzed and the molecular weight is significantly reduced. There are problems such as. Therefore, cooling is preferably performed in a non-aqueous system. For example, an extruded gut-like or sheet-like polymer is placed on a metal roll cooled from the inside.
It is preferable to cool and solidify by contacting once to a plurality of times and then cut with a cutter. In this case, the atmosphere is air without moisture,
Alternatively, an inert gas such as nitrogen is preferable.
【0012】第3工程の固相重合の温度は、ラクチドの
融点以上、ポリ乳酸の融点以下の温度すなわち100〜
170℃、特に120〜165℃が好ましい。固相重合
を効果的に行なうには、ポリマーは充分結晶化させ、残
存モノマー(ラクチド)、重合開始剤及び重合触媒が非
晶部分に集まっていることが好ましい。このため、固相
重合より前又は固相重合の初期に、ポリマーを充分加熱
して結晶化させることが好ましい。ポリ乳酸の結晶化温
度は80〜100℃程度であるから、第2工程又は第3
工程初期に80℃以上、特に100〜160℃で、5分
間〜10時間、好ましくは10分間〜2時間、加熱して
結晶化させることが望ましい。The temperature of the solid-state polymerization in the third step is not lower than the melting point of lactide and not higher than the melting point of polylactic acid, that is, 100 to
170 ° C, particularly preferably 120 to 165 ° C, is preferred. In order to effectively carry out the solid-phase polymerization, it is preferable that the polymer be sufficiently crystallized and the residual monomer (lactide), the polymerization initiator and the polymerization catalyst are collected in the amorphous portion. For this reason, it is preferable that the polymer be sufficiently heated to be crystallized before the solid phase polymerization or at the early stage of the solid phase polymerization. Since the crystallization temperature of polylactic acid is about 80 to 100 ° C., the second step or the third step
It is desirable to crystallize by heating at 80 ° C. or higher, particularly 100 to 160 ° C., for 5 minutes to 10 hours, preferably 10 minutes to 2 hours at the beginning of the process.
【0013】固相重合以前又は固相重合中のポリマーの
結晶化を促進するため、あらかじめ、例えば第1工程で
ポリマー中に結晶核剤を添加しておくことが好ましい。
結晶核剤は、無機微粒子及び/又は高結晶性のポリマー
で、乳酸を主成分とする重合物中に少量混合、分散され
る。結晶核剤は、第1工程の重合原料中に添加してもよ
く、第1工程の末期に重合系内に添加混合してもよい。In order to promote crystallization of the polymer before or during solid phase polymerization, it is preferable to add a nucleating agent to the polymer in advance, for example, in the first step.
The crystal nucleating agent is an inorganic fine particle and / or a highly crystalline polymer, and is mixed and dispersed in a small amount in a polymer mainly composed of lactic acid. The nucleating agent may be added to the polymerization raw material in the first step, or may be added and mixed in the polymerization system at the end of the first step.
【0014】結晶核剤として用いる無機化合物微粒子の
例としては、酸化チタン、酸化亜鉛、硫酸カルシウム、
硫酸バリウム、シリカ、ゼオライト、アルミナ、リン酸
カウシウム、カオリン、炭酸カルシウムなどの、白色又
は白色に近く毒性のない金属酸化物及び/又は金属塩で
直径1nm〜2μm、特に10nm〜0.5μmのもの
が好ましい。同様に、結晶核剤として用いる高結晶性ポ
リマーの例としては、ポリエチレン、ポリプロピレンな
どのポリオレフィン、ポリエチレンテレフタレート、ポ
リブチレンテレフタレート、ポリヒドロキシ安息香酸な
どの芳香族ポリエステル、ポリオキシメタンなどのポリ
エーテルなどで、融点80℃以上、特に100℃以上の
ものが挙げられる。これらの結晶性ポリマーは、乳酸を
主成分とする重合体中に、無機粒子と同程度の大きさ
(直径10nm〜10μm)の微粒子状に分散され、
(冷却後いち早く)結晶化して、ポリ乳酸などのポリマ
ーの結晶核剤として働く。これらの結晶核剤の添加率
は、その粒子径により異なるが、1ppm〜5重量%、
特に10ppm〜1重量%が好ましい。例えば直径10
nmの粒子が直径1μmの球晶の核になったとすると、
核剤の体積分率は1ppmと計算される。実際は、すべ
ての粒子が完全に分散し核剤として有効に働くことはな
いので、計算値の10倍以上、時には100倍以上の過
剰の核剤を添加することが多い。Examples of the inorganic compound fine particles used as a crystal nucleating agent include titanium oxide, zinc oxide, calcium sulfate,
Metal oxides and / or metal salts having a diameter of 1 nm to 2 μm, particularly 10 nm to 0.5 μm, such as barium sulfate, silica, zeolite, alumina, casium phosphate, kaolin, and calcium carbonate, which are white or almost non-toxic and have no toxicity. Is preferred. Similarly, examples of the highly crystalline polymer used as a crystal nucleating agent include polyethylene, polyolefins such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, aromatic polyesters such as polyhydroxybenzoic acid, and polyethers such as polyoxymethane. And a melting point of 80 ° C. or higher, particularly 100 ° C. or higher. These crystalline polymers are dispersed in a polymer containing lactic acid as a main component in the form of fine particles having a size similar to that of the inorganic particles (diameter: 10 nm to 10 μm),
It crystallizes (early after cooling) and acts as a crystal nucleating agent for polymers such as polylactic acid. The addition rate of these nucleating agents varies depending on the particle size, but is 1 ppm to 5% by weight,
Particularly, 10 ppm to 1% by weight is preferable. For example, diameter 10
If a particle of nm becomes the nucleus of a spherulite with a diameter of 1 μm,
The volume fraction of the nucleating agent is calculated as 1 ppm. In practice, all the particles are not completely dispersed and do not function effectively as a nucleating agent, so that an excess of nucleating agent of 10 times or more, sometimes 100 times or more of the calculated value is often added.
【0015】第3工程の固相重合は、チップ(ペレッ
ト)状の重合物を加熱することにより行う。チップは空
気又は窒素などの不活性気体中で加熱してもよく、水分
を除去し重合を促進するため真空中で加熱してもよい。
加熱温度は前述のように100〜170℃、特に120
〜165℃が好ましく、加熱時間は1〜100時間、特
に5〜50時間が好ましい。工業的には、例えば円筒型
の金属製の縦型タンクにチップを充填し、下方から加熱
した窒素ガスを供給し上方から排気し、チップは連続的
に上方から供給し、下方から連続的に取出することによ
り、容易且つ効率的に行なうことが出来る。また第3工
程を2つに分け、前半は、重合物を結晶化させラクチド
の蒸発を防ぐため比較的低温(100〜150℃)で常
圧化長時間(20〜50時間)行ない、後半はやや高温
(160℃)で減圧下に短時間(10〜30時間)行な
うなどとすることも出来る。The solid-phase polymerization in the third step is performed by heating a polymer in the form of chips (pellets). The chips may be heated in an inert gas such as air or nitrogen, or may be heated in a vacuum to remove moisture and promote polymerization.
The heating temperature is 100 to 170 ° C. as described above, particularly 120 ° C.
To 165 ° C, and the heating time is preferably 1 to 100 hours, particularly preferably 5 to 50 hours. Industrially, for example, a cylindrical metal vertical tank is filled with chips, heated nitrogen gas is supplied from below and exhausted from above, chips are continuously supplied from above, and chips are continuously supplied from below. By taking it out, it can be done easily and efficiently. Further, the third step is divided into two parts. In the first half, a relatively low temperature (100 to 150 ° C.) and a normal pressure for a long time (20 to 50 hours) are performed at a relatively low temperature (100 to 150 ° C.) in order to crystallize the polymer and prevent lactide evaporation. It may be carried out at a slightly elevated temperature (160 ° C.) under reduced pressure for a short time (10 to 30 hours).
【0016】第3工程固相重合後の重合体の分子量は、
5万〜50万、特に8万〜30万が好ましく、残存モノ
マー(ラクチド)の含有量は5重量%以下、特に3%以
下が好ましく、2%以下が最も好ましい。Third Step The molecular weight of the polymer after the solid phase polymerization is as follows:
It is preferably from 50,000 to 500,000, particularly from 80,000 to 300,000, and the content of the residual monomer (lactide) is preferably 5% by weight or less, particularly preferably 3% or less, most preferably 2% or less.
【0017】本発明において、乳酸を主成分とする重合
体の平均分子量は、試料のクロロホルム0.1重量%溶
液のGPC(ポリスチレン標準試料による較正)分析
の、高分子物(分子量500以下のものを除く)の分散
の、重量平均値とする。同様に、残存モノマーも、既知
ラクチドを用いて較正したGPC法、その他の液体クロ
マトグラフィー法で測定する。本発明において、部及び
%は特に断らない限り重量部、重量%である。In the present invention, the average molecular weight of a polymer containing lactic acid as a main component is determined by the GPC (calibration using a polystyrene standard sample) analysis of a 0.1% by weight solution of a chloroform solution of a sample. ), And the weighted average value. Similarly, the residual monomer is measured by a GPC method calibrated using a known lactide or another liquid chromatography method. In the present invention, parts and percentages are by weight unless otherwise specified.
【0018】[0018]
(実施例1)光学純度99.9%以上のL−ラクチドに
対し、重合触媒として0.3%のオクチル酸錫、酸化防
止剤としてチバガイギ−社製イルガノックス1010を
0.1%、流動性改善剤としてステアリン酸マグネシウ
ム0.3%,結晶核剤として直径0.1μmの酸化チタ
ン0.5%又は分子量5万の粉末状高密度ポリエチレン
1.0%を混合して2軸混練機に供給し、190℃で1
2分間重合して、孔径2mmの孔より押出し、窒素中で
5本の冷却金属ロール(5℃)に接触固化し、カッター
で切断して直径3.2mm、長さ2.5mmのチップを
得た。第1工程の2軸混練機の最終ベント孔より、重合
開始剤としてグリセリン0.1%、ラウリルアルコール
0.2%、トリエチレングリコール0.1%、分子量4
00のポリエチレングリコール0.2%を夫々混合して
実験した。得たチップを夫々120℃、窒素雰囲気中で
10時間熱処理(結晶化及び初期固相重合)し、次に1
60℃で20時間固相重合した。比較のため、結晶核剤
及び重合開始を加えない実験も、同様に行なった。各実
験で得られた重合体の平均分子量と残存モノマー量を表
1に示す。(Example 1) For L-lactide having an optical purity of 99.9% or more, 0.1% of tin octylate as a polymerization catalyst, 0.1% of Irganox 1010 manufactured by Ciba-Geigy as an antioxidant, and fluidity. 0.3% of magnesium stearate as an improver, 0.5% of titanium oxide having a diameter of 0.1 μm or 1.0% of powdery high-density polyethylene having a molecular weight of 50,000 as a nucleating agent are mixed and supplied to a twin-screw kneader. And at 190 ° C
Polymerized for 2 minutes, extruded from a hole with a hole diameter of 2 mm, solidified in contact with five cooling metal rolls (5 ° C.) in nitrogen, and cut with a cutter to obtain a chip having a diameter of 3.2 mm and a length of 2.5 mm. Was. From the final vent hole of the twin screw kneader of the first step, glycerin 0.1%, lauryl alcohol 0.2%, triethylene glycol 0.1%, molecular weight 4 as a polymerization initiator
The experiment was carried out by mixing 0.2% of polyethylene glycol 0.2% each. Each of the obtained chips was heat-treated (crystallization and initial solid-phase polymerization) at 120 ° C. in a nitrogen atmosphere for 10 hours.
Solid phase polymerization was carried out at 60 ° C. for 20 hours. For comparison, an experiment in which the nucleating agent and the polymerization initiation were not added was also performed in the same manner. Table 1 shows the average molecular weight and residual monomer content of the polymer obtained in each experiment.
【0019】[0019]
【表1】 表1に見るように、結晶核剤及び重合開始剤は、分子量
増大効果及び残存モノマー低減効果が認められる。[Table 1] As shown in Table 1, the nucleating agent and the polymerization initiator have an effect of increasing the molecular weight and an effect of reducing the residual monomer.
【0020】(実施例2)実施例1とほぼ同様にして、
但し主重合原料として、L−ラクチドに対し直径10n
mのシリカ粒子を0.1%混合したものを溶融して2軸
混練機に計量、供給し、他方、重合触媒としてオクチル
酸錫、酸化防止剤イルガノックス1010、流動性改善
剤ステアリン酸マグネシウム、結晶核剤として直径10
nmのシリカ粒子を、共重合成分である分子量8000
ポリエチレングリコール(PEG)に溶融、混合したも
のを2軸混練機に計算、供給する。オクチル酸錫、イル
ガノックス1010、ステアリン酸マグネシウム、シリ
カ粒子、PEGは、夫々L−ラクチドに対して0.3
%、0.1%、0.3%、0.1%、2%となるように
配合する。以下、実施例1と同様に、2軸混練機の最終
ベント孔より、ヘキサンジオール、ε−カプロラクト
ン、ヘキサンアジペートのオリゴマーで両末端が水酸基
で平均重合度が4のものを、夫々0.1%、0.2%、
0.3%混合した。以下重合物の冷却、固化、チップ
化、固相重合を行った結果を表2に示す。表2に見るよ
に、比較例に比べて、本発明による実験No.9−11
のポリマーは、分子量が高く、残存モノマーが少ないこ
とが認められる。(Embodiment 2) In substantially the same manner as in Embodiment 1,
However, as a main polymerization raw material, the diameter of L-lactide is 10 n.
m is mixed and metered and supplied to a twin-screw kneader, while tin octylate, an antioxidant Irganox 1010, a fluidity improver magnesium stearate, Diameter 10 as nucleating agent
of silica particles having a molecular weight of 8000 as a copolymer component.
The melted and mixed product of polyethylene glycol (PEG) is calculated and supplied to a twin-screw kneader. Tin octylate, Irganox 1010, magnesium stearate, silica particles, and PEG were 0.3 to L-lactide, respectively.
%, 0.1%, 0.3%, 0.1%, and 2%. In the same manner as in Example 1, oligomers of hexanediol, ε-caprolactone, and hexaneadipate having hydroxyl groups at both ends and an average degree of polymerization of 4 from the final vent hole of the twin-screw kneader were 0.1% each. , 0.2%,
0.3% was mixed. Table 2 shows the results of cooling, solidification, chipping, and solid-phase polymerization of the polymer. As can be seen from Table 2, Experiment No. 1 according to the present invention was compared with Comparative Example. 9-11
It is recognized that the polymer has a high molecular weight and a low residual monomer.
【0021】[0021]
【表2】 [Table 2]
【0022】[0022]
【発明の効果】本発明によって、重合度が高く、残存モ
ノマーが少ない乳酸を主成分とする重合体を、容易且つ
効果的に低コストで製造することが出来る。得られる重
合体は着色等が少なく品質に優れ、成型品、フィルム、
シート、繊維、編織物、不織布、紙、その他の製品とし
て各種用途に使用し、優れた成型性、加工性、熱加塑
性、分解性を活用することが出来る。According to the present invention, a polymer containing lactic acid as a main component having a high degree of polymerization and a small amount of residual monomers can be easily and effectively produced at low cost. The resulting polymer has less coloration and other excellent quality, molded products, films,
It can be used for various applications as sheets, fibers, knitted fabrics, nonwoven fabrics, papers and other products, and can utilize excellent moldability, workability, thermoplasticity and decomposability.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 小原 仁実 京都市中京区西ノ京桑原町1番地 株式 会社島津製作所 三条工場内 (72)発明者 小関 英一 京都市中京区西ノ京桑原町1番地 株式 会社島津製作所 三条工場内 (72)発明者 澤 誠治 京都市中京区西ノ京桑原町1番地 株式 会社島津製作所 三条工場内 (72)発明者 藤井 康宏 京都市中京区西ノ京桑原町1番地 株式 会社島津製作所 三条工場内 (56)参考文献 特開 昭63−17929(JP,A) (58)調査した分野(Int.Cl.7,DB名) C08G 63/00 - 63/91 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hitomi Ohara 1 Shiwazu Works, Shimanzu Seisakusho Co., Ltd., Shigazu, Nakagyo-ku, Kyoto, Japan Inside the plant (72) Inventor Seiji Sawa 1 Nishinokyo Kuwaharacho, Nakagyo-ku, Kyoto Shimazu Works Sanjo Plant (72) Inventor Yasuhiro Fujii 1 Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto Shimazu Works Sanjo Factory (56) Reference Reference JP-A-63-17929 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C08G 63/00-63/91
Claims (5)
主成分とする重合原料を溶融重合し(第1工程)、次い
で重合したポリマーの冷却固化とチップ化をし(第2工
程)、更に該チップの固相重合を行う(第3工程)際
に、この固相重合工程の初期に該チップ中に、重合系に
対し0.1〜3重量%のアルコール又はラクトンを存在
せしめる事を特徴とする重合体の製造方法。1. A polymerization raw material containing L-lactide and / or D-lactide as a main component is melt-polymerized (first step), and then the polymerized polymer is cooled and solidified into chips (second step). When the solid phase polymerization of the chip is performed (third step) , a polymerization system is added to the chip at the beginning of the solid phase polymerization step.
A method for producing a polymer, characterized in that 0.1 to 3% by weight of alcohol or lactone is present.
ル及び/又はラクトンを、第1工程の末期から第3工程
の初期までの間に添加することを特徴とする請求項1記
載の方法。2. The method according to claim 1, wherein the alcohol and / or lactone present at the beginning of the third step is added between the end of the first step and the beginning of the third step.
び/又はラクトンが、沸点100℃以上のものであるこ
とを特徴とする請求項1〜2のいずれかに記載の方法。Wherein the alcohol and / or lactone initially present in the third step, the method according to any one of claims 1-2, characterized in that is more than the boiling point 100 ° C..
及び/又は高結晶性ポリマーからなる結晶核剤を添加
し、乳酸を主成分とする重合体を結晶化させつつ、又は
結晶化させた後、固相重合させることを特徴とする請求
項1〜3のいずれかに記載の方法。4. A nucleating agent composed of fine particles of an inorganic compound and / or a highly crystalline polymer is added to a polymerization system in advance, and while the lactic acid-based polymer is crystallized or after crystallization, The method according to any one of claims 1 to 3, wherein solid phase polymerization is performed.
℃の温度で1時間〜100時間行うことを特徴とする請
求項1〜4のいずれかに記載の方法。5. The solid-phase polymerization of the third step is carried out at 100 to 170.
The method according to any one of claims 1 to 4, characterized in that 1 to 100 hours at a temperature of ° C..
Priority Applications (1)
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---|---|---|---|
JP02092895A JP3350606B2 (en) | 1995-01-13 | 1995-01-13 | Method for producing polylactic acid |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP02092895A JP3350606B2 (en) | 1995-01-13 | 1995-01-13 | Method for producing polylactic acid |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH08193124A JPH08193124A (en) | 1996-07-30 |
JP3350606B2 true JP3350606B2 (en) | 2002-11-25 |
Family
ID=12040885
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JP02092895A Expired - Fee Related JP3350606B2 (en) | 1995-01-13 | 1995-01-13 | Method for producing polylactic acid |
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Families Citing this family (10)
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---|---|---|---|---|
WO2000078840A1 (en) * | 1999-06-22 | 2000-12-28 | Mitsui Chemicals, Inc. | Process for producing polyhydroxycarboxylic acid |
JP4651802B2 (en) * | 1999-10-27 | 2011-03-16 | 三井化学株式会社 | Method for producing aliphatic polyester having excellent stability |
JP5276240B2 (en) * | 1999-10-27 | 2013-08-28 | 三井化学株式会社 | Solid phase polymerization method of aliphatic polyester |
JP2005350829A (en) * | 2004-06-14 | 2005-12-22 | Nippon Ester Co Ltd | Polylactic acid fiber having excellent hydrolytic resistance |
JP5485988B2 (en) * | 2008-06-12 | 2014-05-07 | スリーエム イノベイティブ プロパティズ カンパニー | Melt blown fine fiber and manufacturing method |
JP5652831B2 (en) * | 2010-05-10 | 2015-01-14 | 国立大学法人群馬大学 | Method for producing polylactic acid fine particles, polylactic acid fine particles, and crystal nucleating agent, molded article, and surface modifier using the same |
MY162777A (en) * | 2010-09-28 | 2017-07-14 | Toray Industries | Process for production of poly(lactic acid)-type resin, and poly(lactic acid)-type prepolymer |
ES2671944T3 (en) | 2011-07-28 | 2018-06-11 | Natureworks Llc | Poly (lactic acid) resin and method to produce it |
JPWO2013141126A1 (en) * | 2012-03-19 | 2015-08-03 | ユニチカ株式会社 | Polylactic acid resin composition and polylactic acid film formed by molding the same |
KR101713215B1 (en) | 2015-08-11 | 2017-03-07 | 롯데케미칼 주식회사 | Preparation method of polylactic acid |
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