JPS6264823A - Production of polyglycolide or polylactide - Google Patents
Production of polyglycolide or polylactideInfo
- Publication number
- JPS6264823A JPS6264823A JP60205955A JP20595585A JPS6264823A JP S6264823 A JPS6264823 A JP S6264823A JP 60205955 A JP60205955 A JP 60205955A JP 20595585 A JP20595585 A JP 20595585A JP S6264823 A JPS6264823 A JP S6264823A
- Authority
- JP
- Japan
- Prior art keywords
- reaction
- molecular weight
- liquid paraffin
- polylactide
- polycondensate
- 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.)
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- Agricultural Chemicals And Associated Chemicals (AREA)
- Polyesters Or Polycarbonates (AREA)
- Medicinal Preparation (AREA)
- Materials For Medical Uses (AREA)
Abstract
Description
【発明の詳細な説明】
(産業上の利用分野)
本発明はグリコール酸、乳酸の脱水重縮合反応によって
得られるポリクリコリ1−、ポリラクチドの製造方法に
関し、殊tこ徐放性重合体として有用なる高分子量のポ
リクリコリド、ボリラクチ1を提供することを目的とす
るものである。Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for producing polycricoli-1- and polylactide obtained by dehydration polycondensation reaction of glycolic acid and lactic acid, which are particularly useful as sustained-release polymers. The purpose of this invention is to provide a high molecular weight polycricolide, Vorilacti 1.
ポリクリコリド、ボリラクチ1〜は徐放性重合体として
、縫合糸等の生体分解性医用材料、除草剤、土壌殺菌剤
等の土壌処理用農薬組成物。Polycricolide and Vorilacti 1~ are used as sustained release polymers for biodegradable medical materials such as sutures, and agricultural chemical compositions for soil treatment such as herbicides and soil fungicides.
マイクロカプセルとしての基剤等として、近年多方面F
こ利用されている。In recent years, F has been widely used as a base material for microcapsules, etc.
This is being used.
この徐放性重合体が具有すへぎ条件として、農薬組成物
の場合では長期間tこわたり薬剤成分を放出することか
必要とされ、そのためには適度に高分子量であることが
必要である。 また医用材料として使用される場合につ
いても重合体材料が生体に癒合するまでの期間tこ必要
な強度を保持し、その後は速やかに分解吸収されること
か必要であり、同様に高分子量の重合体が要求されてい
る。In the case of agricultural chemical compositions, this sustained-release polymer must be able to release the drug component over a long period of time, and for this purpose, it must have a suitably high molecular weight. In addition, when used as a medical material, it is necessary for the polymer material to maintain the necessary strength for a period of time until it fuses with the living body, and then be quickly decomposed and absorbed. A merger is required.
(従来の技術)
高分子量のポリグリコリド、ポリラクチドを得る方法と
して一般にグリコール酸、4L酸からグリコリド、ラク
チドを製造し、これを開環重合し、ポリグリコリド、ポ
リラクチドを製造する方法が知られているが、この方法
によると高分子量のものが得られる反面、グリコリド、
ラクチドの製造に際して多大の労力と費用を必要とし、
経済的でない。 また別の方法として、グリコール酸、
乳酸から直接ポリグリコリド。(Prior art) A generally known method for obtaining high molecular weight polyglycolide and polylactide is to produce glycolide and lactide from glycolic acid and 4L acid, and then ring-opening polymerize them to produce polyglycolide and polylactide. However, although this method yields products with high molecular weight, glycolide,
The production of lactide requires a great deal of labor and expense;
Not economical. Another method is glycolic acid,
Polyglycolide directly from lactic acid.
ポリラクチドを得る方法があるか、この方法は簡易な重
縮合方法である反面、高分子量の重縮合体が得られない
。Is there a method for obtaining polylactide? Although this method is a simple polycondensation method, it does not yield a high molecular weight polycondensate.
(発明が解決しようとする問題点)
そこで本発明者らは安価で高分子量の重縮金品を得べく
、グリコール酸、乳酸からの直接重縮合法による検討を
行なった。(Problems to be Solved by the Invention) Therefore, the present inventors conducted an investigation using a direct polycondensation method from glycolic acid and lactic acid in order to obtain an inexpensive polycondensed metal product with a high molecular weight.
グリコール酸、乳酸の直接重縮合反応は、二塩基酸と多
価のアルコールによるエステル化反応と同様に逐次反応
であり、反応時間と共に分子量は増大する。The direct polycondensation reaction of glycolic acid and lactic acid is a sequential reaction similar to the esterification reaction between a dibasic acid and a polyhydric alcohol, and the molecular weight increases with the reaction time.
また、この時生成する水分子は重縮合反応で逐次上昇す
る重縮合体の分子量を、その加水分解作用により低下さ
せる作用を有するので、重縮合時に生成する水を反応系
内から除去することが、高分子量化の為の重要な要因と
なる。In addition, the water molecules produced at this time have the effect of lowering the molecular weight of the polycondensate, which increases successively in the polycondensation reaction, by its hydrolytic action, so it is possible to remove the water produced during the polycondensation from the reaction system. , is an important factor for increasing the molecular weight.
この生成する水分子を反応系内より系外へ除去する方法
として、反応時tこ攪拌速度を高める機械的方法、減圧
度を高める方法、N2ガスを反応系やこ導入する場合の
N、ガス流量を増加させる方法等により、水分子を揮散
させ除去する方法があるが、分子量の増大と共に反応系
の粘度は上昇することにより、これらの方法eこより、
水分子を除去することは、反応の進行と共に困難となる
。Methods for removing the generated water molecules from inside the reaction system to outside the reaction system include a mechanical method of increasing the stirring speed during the reaction, a method of increasing the degree of vacuum, and a method of increasing the N2 gas flow rate when introducing N2 gas into the reaction system. There are methods to volatilize and remove water molecules by increasing the
Removal of water molecules becomes difficult as the reaction progresses.
従って、上昇する反応液の粘度を抑制し、反応の進行と
共tこ生成する水分を前記の操作により効率的に反応系
外へ除去することが、重縮合体を高分子量化させるため
の重要な手段である。Therefore, it is important to suppress the rising viscosity of the reaction solution and to efficiently remove the water generated as the reaction progresses out of the reaction system by the above-mentioned operation in order to increase the molecular weight of the polycondensate. It is a method.
(問題点を解決するための手段)
本発明者らはこれらの知見をもとに、グリコール酸、乳
酸の脱水重縮合反応が高分子量のポリグリコリドまたは
ポリラクチドを得べく鋭意研究を重ねた結果、流動パラ
フィンの使用tこより反応系内の粘度上列を抑制し、効
果的に水の拡散速度を上昇せしめ、以って高分子量の重
縮合体を得ることが可能なることを見い出し、本発明を
完成したものである。(Means for Solving the Problems) Based on these findings, the present inventors have conducted intensive research to obtain high molecular weight polyglycolide or polylactide through the dehydration polycondensation reaction of glycolic acid and lactic acid. It has been discovered that the use of liquid paraffin suppresses the increase in viscosity within the reaction system and effectively increases the diffusion rate of water, thereby making it possible to obtain a high molecular weight polycondensate, and has developed the present invention. It is completed.
即ち、本発明はポリグリコ1ノドまたはポリラクチドの
製造tこおいて、重縮合時tこ流動パラフィンを使用す
ることからなるポリグリコリドまたはポリラクチドの製
造法に関し、徐放性高分子材料等に適する高分子量のポ
リグリコリド、ポリラクチドを得る方法に関する。That is, the present invention relates to a method for producing polyglycolide or polylactide, which comprises using liquid paraffin during polycondensation, and the present invention relates to a method for producing polyglycolide or polylactide, which comprises using liquid paraffin during polycondensation. The present invention relates to a method for obtaining polyglycolide and polylactide.
(作 用) 本発明に使用する化ツマ−は、グリコール酸。(for production) The chemical compound used in the present invention is glycolic acid.
乳酸であって、乳酸に関してはD型またはL型のいずれ
であっても、あるいはラセミ体であってもよい。Lactic acid may be either D-type or L-type, or racemic.
反応を行なう際tここれらの濃度について特に限定はさ
れないが、重縮合反応開始時の濃度が低い場合には反応
の初期に生成するオリゴマー等の揮散量が多くなり、収
率が低下することから、モノマー濃度が低い場合には開
始前、適度に濃縮を行ない使用することが望ましい。There are no particular limitations on the concentrations of these components when carrying out the reaction, but if the concentration at the start of the polycondensation reaction is low, the amount of oligomers etc. produced at the beginning of the reaction will increase and the yield will decrease. When the monomer concentration is low, it is desirable to perform appropriate concentration before use.
重縮合反応の方法は、通常触媒を使用し、上記化ツマ−
に触媒を添加後、密封減圧下、または窒素ガフ等の不活
性ガスの導入下で150〜250℃に加温をしながら行
なう。The polycondensation reaction method usually uses a catalyst and
After adding a catalyst, the reaction is carried out while heating to 150 to 250° C. under sealed reduced pressure or while introducing an inert gas such as a nitrogen gaff.
使用する触媒としては、塩化第1ヌズ、硫酸第1スズ、
酸化第1ヌズ、酸化第2ヌズ、テトラフェニルスズ、金
属スズ粉末、四塩化チタン。The catalysts used include stannous chloride, stannous sulfate,
No. 1 oxide, No. 2 oxide, tetraphenyltin, metal tin powder, titanium tetrachloride.
酸化亜鉛、酸化アンチモン、塩化アンチモン。Zinc oxide, antimony oxide, antimony chloride.
酸化鉛、酸化カルシウム、酸化ヌトロンチウム。Lead oxide, calcium oxide, nutrontium oxide.
酸化7 /l/ ミニラム、酸化鉄、塩化カルシウム。Oxidation 7/l/ Minirum, iron oxide, calcium chloride.
酢酸亜鉛、P−1ルエンスルホン酸等を用いることがで
きる。Zinc acetate, P-1 luenesulfonic acid, etc. can be used.
また、これらの添加量に関しては、特に限定はされない
が、通常グリコール酸または乳酸のモノマ1に対して0
01〜10重量%の範囲で使用する。There are no particular limitations on the amount of these added, but usually 0 to 1 monomer of glycolic acid or lactic acid.
It is used in a range of 0.01 to 10% by weight.
反応の開始後、重縮合体の分子量は遂次上昇するか、本
発明はこの時の分子量が2000〜6000の範囲とな
った時eこ流動パラフィンを添加する。 流動パラフィ
ンの添加(こより&心数の粘度増加は抑制され、遂次生
成する水は反応糸夕1にff易に拡散除去される。After the start of the reaction, the molecular weight of the polycondensate increases gradually, and in the present invention, liquid paraffin is added when the molecular weight is in the range of 2,000 to 6,000. The addition of liquid paraffin suppresses the increase in viscosity and the number of fibers, and the water that is successively produced is easily diffused into the reaction yarn 1 and removed.
」−列する重縮合体の分子量は一定時間毎に反応液を採
取し、次の方法で分子量測定を行なう。- To determine the molecular weight of the polycondensate in the column, sample the reaction solution at regular intervals and measure the molecular weight using the following method.
〈分子量測定方法〉
反応f4ftの約12を20meのペンシルアルコール
に加熱溶解し、冷却後フェノールフタレインヲ指示薬e
こ用い0.025Nの水酸化カリウムのベンジルアルコ
ール溶液で滴定する。 滴定に際1、では空気中の二酸
化炭素等の妨害を除去するためN、ガスを導入1〜なが
ら窒素雰囲気下で行なう。<Molecular weight measurement method> About 12 of the reaction f4ft was heated and dissolved in 20me pencil alcohol, and after cooling, phenolphthalein was added as an indicator e.
This is then titrated with a 0.025N potassium hydroxide solution in benzyl alcohol. During the titration, in step 1, nitrogen gas is introduced in order to remove interference such as carbon dioxide in the air, and the titration is carried out under a nitrogen atmosphere.
滴定値より次式tこより重縮合体の分子量を求める。The molecular weight of the polycondensate is determined from the titration value using the following formula t.
0025f(S−13)
但し W、重縮合体重量(y)
f:o、025N水酸化カリウム溶花のファクターS
// 滴定量(サンプル)B
// 滴定量(≠ランク)Mn: 重縮合
体の数平均分子量
尚、この方法は、重縮合体末端基のカルボギシル基量を
定量することにより、この値から分子量を算出し求める
ものであり、また本発明で云う分子量は数平均分子量を
云う。0025f (S-13) However, W, polycondensation weight (y) f: o, factor S of 025N potassium hydroxide melt flower
// Titration amount (sample) B
// Titration amount (≠ rank) Mn: Number average molecular weight of the polycondensate In addition, in this method, the molecular weight is calculated from this value by quantifying the amount of carbogyyl groups of the terminal groups of the polycondensate. Moreover, the molecular weight referred to in the present invention refers to the number average molecular weight.
重縮合体の分子量は、反応開始後約2〜10時間で20
00〜6000の範囲となるか、この範囲内に於て流動
パラフィンの添加を行なう。The molecular weight of the polycondensate decreases to 20% approximately 2 to 10 hours after the start of the reaction.
00 to 6000, or liquid paraffin is added within this range.
本発明ではこの流動パラフィンの添加時期は殊tこ重要
であり、重縮合体の分子量か2000未満、あるいは6
000を越える時点での添加では高分子量の重縮合体を
得ることができない。In the present invention, the timing of addition of this liquid paraffin is particularly important; the molecular weight of the polycondensate is less than 2000, or
If it is added at a point exceeding 0.000, it is not possible to obtain a high molecular weight polycondensate.
流動パラフィンの使用割合に関して云えば、使用するモ
ノマー、触媒の種類及び濃度7反応温度等eこよって異
なるが、大略グリコール酸または乳酸のモノマー量tこ
対して、5〜30M量%の範囲で用いる。Regarding the proportion of liquid paraffin used, it varies depending on the monomers used, the type of catalyst, the concentration, the reaction temperature, etc., but it is generally used in the range of 5 to 30 M% relative to the monomer amount of glycolic acid or lactic acid. .
即ち、下限未満では本発明の効果を期待することかでき
ず、また上限を越える流動パラフィンの添加は、逆に水
の系列への揮散を阻害する結果、高分子量の重縮合体を
得ることができない。That is, if the amount of liquid paraffin is less than the lower limit, the effect of the present invention cannot be expected, and if the liquid paraffin is added in excess of the upper limit, it will conversely inhibit the volatilization of water into the series, making it difficult to obtain a high molecular weight polycondensate. Can not.
流動パラフィンの添加後は、反応を約1〜20時間継続
することeこより、本発明の重縮合体が得られる。 尚
、流動パラフィンの添加方法は、分子i: 2000〜
6000の 範囲内であれは連続的であっても間欠的で
あってもよい。After adding the liquid paraffin, the reaction is continued for about 1 to 20 hours, thereby obtaining the polycondensate of the present invention. In addition, the method of adding liquid paraffin is as follows: molecule i: 2000~
It may be continuous or intermittent within the range of 6000.
(発明の効果)
本発明の方法により得られる重縮合体の分子量は高く、
流動パラフィンを使用せずに得られる重縮合体の数平均
分子量が通常約7000を限界とするのに対して、本発
明の方法によれば、分子量は約1000Ofこまで」1
外させることができる。(Effect of the invention) The molecular weight of the polycondensate obtained by the method of the invention is high;
While the number average molecular weight of polycondensates obtained without using liquid paraffin is usually limited to about 7,000, according to the method of the present invention, the molecular weight can be reduced to about 1,000.
It can be removed.
また先tこ記したグリコリド、ラクチドからの開環重合
によりポリグリコリド、ポリラクチドを得る方法に於て
も、本発明の方法を応用することにより、より高分子量
の重縮合体を得ることが可能なることは云うまでもない
。Furthermore, by applying the method of the present invention to the method of obtaining polyglycolide and polylactide by ring-opening polymerization from glycolide and lactide described above, it is possible to obtain polycondensates with higher molecular weight. Needless to say.
本発明の方法により製造されたポリグリコリ1−または
ポリラクチドは高分子量であるから、その強度が大きい
等の優れた特性を有し、従って徐放性基材として例えは
、生体吸収材料、医薬、農薬等の薬剤徐放性マl−IJ
ックヌ、マイクロカフ9セル基剤、土壌改良剤への利用
のみならず、崩壊性農業用フィルム、界面活性剤、果実
の品質向−ト剤、気体分離透過膜等幅広い利用用途を有
する。Since the polyglycol 1- or polylactide produced by the method of the present invention has a high molecular weight, it has excellent properties such as high strength. Drug sustained release mal-IJ such as
It has a wide range of uses, including not only Kunu, Microcuff 9-cell base, and soil conditioner, but also disintegrating agricultural films, surfactants, fruit quality improving agents, gas separation permeable membranes, etc.
(実施例)
本発明を更に詳細に説明するためtこ、以下に実施例を
挙げて説明を行なうか、本発明はこれらに限定されるも
のではない。(Examples) In order to explain the present invention in more detail, the present invention will be described below with reference to Examples, but the present invention is not limited thereto.
尚、本実施例は特にことわらない限り、%は全て重量%
を示す。In this example, unless otherwise specified, all percentages are by weight.
shows.
実施例1
攪拌機、温度計、コンデンサーを備えた500me容フ
ラスコに70%グリコール酸ヲ400 y入れ、攪拌を
しなから温度160℃、減圧度62mmH9でグリコー
ル酸を濃縮した。 約1202の水が留出した後、塩化
第1ヌズ(SnC1r ・2H,O)を0.280y添
加し、温度、減圧度を徐々tこ上列し、225°C、2
[] mmI−Tyで8時間の反応を行なった。 8
時間の反応後のポ→)グア1コリドの分子量は3000
となり、この時流動パラフィンを20.4y(対グリコ
ール酸729%)添加し、再び温度245℃、減圧度5
mmH9で10時間の反応を行なった。Example 1 400 y of 70% glycolic acid was put into a 500 me flask equipped with a stirrer, a thermometer, and a condenser, and while stirring, the glycolic acid was concentrated at a temperature of 160° C. and a degree of vacuum of 62 mm H9. After approximately 1,202 ml of water was distilled off, 0.280 y of primary chloride (SnC1r 2H,O) was added, the temperature and degree of vacuum were gradually increased, and the temperature and vacuum were gradually increased to 225°C.
[] Reaction was carried out for 8 hours with mmI-Ty. 8
After the reaction for hours, the molecular weight of gua 1 colide is 3000
At this time, 20.4y of liquid paraffin (729% based on glycolic acid) was added, and the temperature was 245°C and the degree of vacuum was 5.
The reaction was carried out at mmH9 for 10 hours.
反応の終了後、重縮合体の分子量を測定した結果、分子
量は9800であった。After the reaction was completed, the molecular weight of the polycondensate was measured and found to be 9,800.
また比較のためtこ、前記の流動パラフィンを添加せず
、同様をこ反応を行なった結果、得られたポリグリコリ
ドの分子量は5250であった。For comparison, the same reaction was carried out without adding the liquid paraffin, and the resulting polyglycolide had a molecular weight of 5,250.
実施例2
実施例1と同様のフラスコtこ90%L−乳酸450y
を入れ、攪拌をしながら温度165°C9減圧度30
mmHyでL−乳酸を濃縮した。Example 2 A flask similar to Example 1 contained 450 y of 90% L-lactic acid.
and while stirring, reduce the temperature to 165°C and reduce the pressure to 30°C.
L-lactic acid was concentrated with mmHy.
約45pの水が留出した後、ピロりん酸第1スズ(S
nr Pr O+ )を0.851y添加し、温度、減
圧度を徐々tこ上昇し、200°C、20mmHyで2
〜26時間の反応を行なった。After about 45p of water has distilled out, stannous pyrophosphate (S
nr Pr O+ ) was added for 0.851y, the temperature and degree of vacuum were gradually increased by t, and the mixture was heated to
The reaction was carried out for ~26 hours.
これらの操作を同様に行ない、反応を2〜26時間とし
た時の重縮合体の分子量は、各々第1表に示した通りと
なったが、この時tこ流動パラフィンを216y(対し
一乳酸536%)添加し、再び温度212°C1減圧度
20mmHpで19時間の反応を行なった。When these operations were carried out in the same manner and the reaction was carried out for 2 to 26 hours, the molecular weights of the polycondensates were as shown in Table 1. 536%) was added thereto, and the reaction was carried out again at a temperature of 212° C. and a reduced pressure of 20 mm Hp for 19 hours.
反応の終了後、各々の重縮合体の分子量を測定した結果
を、第1表に示した。After the reaction was completed, the molecular weight of each polycondensate was measured and the results are shown in Table 1.
第1表
実施例6
N、ガス導入管、温度計、コンデンサーを備えたI 0
0 me 容ガラス製の反応器に90%L−乳酸60y
を入れ、これに四塩化チタン(Ti0゜174%水溶液
)を0.059y添加した。Table 1 Example 6 I0 with N, gas inlet pipe, thermometer and condenser
0 me 90% L-lactic acid 60y in a glass reactor
and 0.059y of titanium tetrachloride (0°174% Ti aqueous solution) was added thereto.
N、ガスを200 mel論の流量で反応液中tこ吹込
みながら温度を210°Cに昇温した。 温度を210
℃に保持し、約6時間後に重縮合体の分子量が4000
となった時点で、第2表に示したように流動パラフィン
の所定量を添加し、再びN2ガヌ流量200 me/y
dn 、温度205°Cで18時間の反応を行なった。The temperature was raised to 210° C. while blowing nitrogen gas into the reaction solution at a flow rate of 200 mel. temperature to 210
The molecular weight of the polycondensate reached 4000 after about 6 hours.
At the point when
dn, the reaction was carried out at a temperature of 205°C for 18 hours.
反応の終了後、各々の重縮合体の分子量を測定した結果
を第2表をこ示した。After the reaction was completed, the molecular weight of each polycondensate was measured and the results are shown in Table 2.
第2表
実施例4
N、ガス導入管、温度計、コンデンサーを備えたsso
、1(<容ガラス製の反応器に90%L−乳酸200y
を入れ、 これに塩化第1スズ(Bnalt・2HIO
)をo、oa+y添加した。Table 2 Example 4 SSO equipped with N, gas inlet pipe, thermometer, and condenser
, 1 (<200y of 90% L-lactic acid in a glass reactor
and add stannous chloride (Bnalt・2HIO) to this.
) were added at o, oa+y.
N、ガスを50077rmnの流量で反応液中に吹込み
ながら温度を208℃に昇温した。 温度を208℃に
保持し、約9時間後に重縮合体の分子量が4200とな
った時点で第3表に示した添加物を添加し、N、ガス流
量950 me/win 、温度209℃で14時間の
反応を行なった。The temperature was raised to 208° C. while blowing nitrogen gas into the reaction solution at a flow rate of 50,077 rpm. The temperature was maintained at 208°C, and when the molecular weight of the polycondensate reached 4,200 after about 9 hours, the additives shown in Table 3 were added, and the mixture was heated at 209°C with N and a gas flow rate of 950 me/win. A time reaction was performed.
反応の終了後、各々の重縮合体の分子量を測定した結果
を第6表(こ示した。After the reaction was completed, the molecular weight of each polycondensate was measured and the results are shown in Table 6.
Claims (3)
て、重縮合時に流動パラフィンを使用することからなる
ポリグリコリドまたはポリラクチドの製造法。(1) A method for producing polyglycolide or polylactide, which comprises using liquid paraffin during polycondensation.
はポリラクチドに対して、5〜30重量%である特許請
求の範囲第1項記載の製造法。(2) The production method according to claim 1, wherein the proportion of liquid paraffin used is 5 to 30% by weight based on polyglycolide or polylactide.
量2000〜6000の時である特許請求の範囲第1項
記載の製造法。(3) The production method according to claim 1, wherein the addition of liquid paraffin is started when the molecular weight during polycondensation is 2,000 to 6,000.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP60205955A JPS6264823A (en) | 1985-09-17 | 1985-09-17 | Production of polyglycolide or polylactide |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP60205955A JPS6264823A (en) | 1985-09-17 | 1985-09-17 | Production of polyglycolide or polylactide |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6264823A true JPS6264823A (en) | 1987-03-23 |
JPH0441696B2 JPH0441696B2 (en) | 1992-07-09 |
Family
ID=16515466
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP60205955A Granted JPS6264823A (en) | 1985-09-17 | 1985-09-17 | Production of polyglycolide or polylactide |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6264823A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0603889A2 (en) * | 1992-12-25 | 1994-06-29 | MITSUI TOATSU CHEMICALS, Inc. | Process for the preparation of lactic acid polyesters |
US5434241A (en) * | 1993-04-24 | 1995-07-18 | Korea Institute Of Science And Technology | Biodegradable poly(lactic acid)s having improved physical properties and process for their preparation |
EP0710684A2 (en) | 1994-11-02 | 1996-05-08 | MITSUI TOATSU CHEMICALS, Inc. | Preparation process of polyhydroxycarboxylic acid |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4862899A (en) * | 1971-11-22 | 1973-09-01 | ||
JPS558977A (en) * | 1978-07-07 | 1980-01-22 | Nippon Jiyosetsuki Seisakusho:Kk | Auxiliary apparatus for lighting brake light for vehicle |
-
1985
- 1985-09-17 JP JP60205955A patent/JPS6264823A/en active Granted
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4862899A (en) * | 1971-11-22 | 1973-09-01 | ||
JPS558977A (en) * | 1978-07-07 | 1980-01-22 | Nippon Jiyosetsuki Seisakusho:Kk | Auxiliary apparatus for lighting brake light for vehicle |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0603889A2 (en) * | 1992-12-25 | 1994-06-29 | MITSUI TOATSU CHEMICALS, Inc. | Process for the preparation of lactic acid polyesters |
EP0603889A3 (en) * | 1992-12-25 | 1994-07-20 | MITSUI TOATSU CHEMICALS, Inc. | Process for the preparation of lactic acid polyesters |
US5434241A (en) * | 1993-04-24 | 1995-07-18 | Korea Institute Of Science And Technology | Biodegradable poly(lactic acid)s having improved physical properties and process for their preparation |
EP0710684A2 (en) | 1994-11-02 | 1996-05-08 | MITSUI TOATSU CHEMICALS, Inc. | Preparation process of polyhydroxycarboxylic acid |
US5770683A (en) * | 1994-11-02 | 1998-06-23 | Mitsui Toatsu Chemicals, Inc. | Preparation process of polyhydroxycarboxylic acid |
Also Published As
Publication number | Publication date |
---|---|
JPH0441696B2 (en) | 1992-07-09 |
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