JP3290496B2 - Thermoplastic polymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decomposable thermoplastic polymer composition. For more information,
The present invention relates to a thermoplastic polymer composition mainly composed of a flexible polylactic acid containing a plasticizer or a copolymer of lactic acid and another hydroxycarboxylic acid. These thermoplastic decomposable polymers have recently attracted attention as packaging materials and medical materials.

[0002]

2. Description of the Related Art In recent years, the amount of plastic used for packaging has been increasing due to the problems of aesthetics, hygiene, and packing and transportation of goods. Along with this, the amount of garbage discarded from homes and factories has increased rapidly, and the shortage of land to bury has become a serious problem around large cities.

Conventionally, polyethylene, polypropylene, polystyrene, polyethylene terephthalate, vinyl chloride and the like have been used as such packaging plastics. However, when they are disposed of in the natural environment, they remain without decomposition due to their stability,
It causes problems such as spoiling the landscape and polluting the living environment of marine life.

[0004] Many researches and developments have been made to use degradable polymers that do not cause these problems as packaging materials. For example, there has been an attempt to impart degradability by blending materials such as polyethylene, polypropylene, and polystyrene with starch. However, in this method, it is said that the starch decomposes and the resin itself disintegrates, but the non-decomposable polymer itself remains as it is, thereby promoting environmental pollution.

On the other hand, polylactic acid or a copolymer of lactic acid and another hydroxycarboxylic acid (hereinafter abbreviated as lactic acid-based polymer) has been developed as a biodegradable polymer of a thermoplastic resin. These polymers are 100% biodegradable in the body of animals in months to one year, and when placed in soil or seawater, begin to degrade in weeks in moist environments and disappear in one to several years. Furthermore, the decomposition product has the property of becoming lactic acid, carbon dioxide, and water that are harmless to the human body. However, since polylactic acid is brittle and hard and lacks flexibility, there is a problem when molded into a film or the like.

[0006] US Pat. No. 3,736,646 No. and the same 3,
No. 982,543 discloses that a volatile solvent is used as a plasticizer in order to obtain the flexibility of a lactide copolymer.
There has been disclosed. However, when a solvent is used as a plasticizer, the solvent gradually evaporates during storage or use of a product such as a film, and the effect is lost. Also,
There are problems with food and medical applications in terms of the safety of these solvents.

[0007] US Pat. No. 3,636,956 No. and the same 3,
No. 797,499 discloses an L-lactide / D, L-lactide copolymer used as a surgical suture. These documents have an elongation of about 20% and lack flexibility, and it is described that glycerin triacetate, ethyl benzoate, and diethyl phthalate can be used as a plasticizer to give flexibility. However, these compounds are recently on the film or the like directly touching the food from safety issues tend to refrain use, even doubtful in terms of biological suitability.

[0008] U.S. Patent No. 5, 180, 765 Patent, as a plasticizer, 10-40% of lactic acid or lactide, or 10% to 60% of the following general formula, (2) (Formula 2) with linear, represented Polylactic acid containing lactic acid oligomers or linear lactide oligomers is disclosed. However, there is no description about the cyclic oligomer.

[0009]

Embedded image Further, U.S. Patent No. 5, 076, 983 Patent, an annular dimer of 0.1 to 9% of a hydroxycarboxylic acid as a plasticizer, an oligomer dimer or hydroxycarboxylic acids, hydroxycarboxylic acids not cyclic A film of polyhydroxycarboxylic acid is disclosed, but there is no description about a cyclic oligomer.

Polylactic acid or polyhydroxycarboxylic acid containing such lactic acid, cyclic dimer or linear oligomer considerably has low stability and is easily hydrolyzed under ordinary use conditions. A molded article such as a film made of such a composition has a great disadvantage that the strength is reduced in a relatively short period of time and the molded article cannot be used. Compounds having an active hydrogen terminal, such as lactic acid and linear oligomers, have a problem that the molecular weight of the polymer itself is reduced when the operation of mixing with the polymer at a high temperature is performed.

[0011]

The object of the present invention is to solve the above, the film, thread, packaging material, etc., that Ki particularly de be used for food packaging or medical applications, have a flexibility sufficient under conditions of use An object of the present invention is to obtain a stable thermoplastic composition containing polylactic acid as a main component.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, it has been found that polylactic acid or a copolymer of lactic acid and another hydroxycarboxylic acid containing a cyclic lactic acid oligomer is obtained. They have found that they have flexibility and at the same time have sufficient stability even under normal use conditions, and have completed the present invention.

That is, the present invention relates to a thermoplastic polymer composition containing, as a main component, polylactic acid containing a cyclic oligomer of lactic acid or a copolymer of lactic acid and hydroxycarboxylic acid as a plasticizer. However, many of the following
Porous film-like thermoplastic polymer composition, and
The polymer network-like thermoplastic polymer composition mentioned in
except. Polylactic acid (A) or lactic acid-hydroxycal
80 to 100% by weight of a boronic acid copolymer (B), and
Polylactic acid based resin composition containing 0 to 20% by weight of plasticizer (C)
Fine particles having an average particle size of 0.3 to 4 μm per 100 parts by weight of the product.
Mixture to which 40 to 250 parts by weight of powdery filler (D) is added
After melt forming into a film, at least 1.1 times or more in one axis direction
A porous film-like thermoplastic resin characterized by being stretched
A limmer composition, wherein the polylactic acid (A) is an L-lactic acid unit
85 to 100 mol% and 0 to 15 mol of D-lactic acid unit
% Or 85 to 100 mol% of D-lactic acid units and L
-Containing lactic acid units from 0 to 15 mol%,
The rubonic acid copolymer (B) has an L-lactic acid unit of 85 to 100.
Mol% or 85-100 mol% of D-lactic acid units and
And 0 to 15 mol% of glycolic acid units and a plasticizer
(C) is a lactic acid oligomer or lactide, and
Porous filler in which the fine powder filler (D) is an inorganic fine powder
Rubber-like thermoplastic polymer composition. Polylactic acid (A) or
Is a lactic acid-hydroxycarboxylic acid copolymer (B) 80-
100% by weight and 0 to 20% by weight of the plasticizer (C)
100 parts by weight of a polylactic acid-based resin composition containing
Melt foam extrusion of the mixture with 0.2 to 10 parts by weight
And open fiber polymer network-like thermoplastic polymer composition
The polylactic acid (A) has an L-lactic acid unit of 85 to 10
0 mol% and 0 to 15 mol % of D-lactic acid unit , or
85 to 100 mol% of D-lactic acid unit and 0 of L-lactic acid unit
Lactic acid-hydroxycarboxylic acid
The limmer (B) has 85 to 100 mol% of L-lactic acid units, and
Is 85 to 100 mol% of D-lactic acid units and glycol
Containing 0 to 15 mol% of an acid unit and containing a plasticizer (C) as milk
Polymeric reticulated polymer which is acid oligomer or lactide
Plastic polymer composition.

The polymer used in the present invention is polylactic acid or a copolymer of polylactic acid and another hydroxycarboxylic acid (hereinafter collectively referred to as a polylactic acid-based polymer).
And other hydroxycarboxylic acids include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid,
4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid and the like are used.

The polylactic acid-based polymer may be directly dehydrated and polycondensed from lactic acid or lactic acid and another hydroxycarboxylic acid,
Lactide as a cyclic dimer of lactic acid or cyclic ester intermediate of hydroxycarboxylic acid, for example, glycolide (GLD) as a dimer of glycolic acid or ε-caprolactone (CL) as a cyclic ester of 6-hydroxycaproic acid It may be those obtained by ring-opening polymerization using a copolymerizable monomer like as appropriate.

In the case of direct dehydration condensation, lactic acid or lactic acid and another hydroxycarboxylic acid are preferably dehydrated and condensed in the presence of an organic solvent, particularly a phenyl ether-based solvent, and particularly preferably from a solvent distilled off by azeotropic distillation. By polymerizing by a method of returning the substantially anhydrous solvent to the reaction system by removing water, high-molecular-weight polylactic acid having strength suitable for the present invention can be obtained.

Lactic acid as a raw material is L-lactic acid or D-lactic acid.
Either lactic acid or a mixture thereof may be used.

The cyclic oligomer of lactic acid used as a plasticizer is represented by the following general formula (1) , wherein n is preferably an integer of 3 to 200. Particularly preferably, it is 10 to 100.

[0019]

Embedded image Further, each lactic acid unit may be L-lactic acid or D-lactic acid. The production method is not particularly limited.For example, a high-molecular-weight linear polylactic acid produced by dehydration-condensation of lactic acid in a dilute solution and a cyclic lactic acid oligomer which remains at a relatively low molecular weight are separated by a fractional precipitation method. Can be manufactured.

As a method for adding the cyclic lactic acid oligomer of the present invention to a lactic acid-based polymer, the lactic acid-based polymer and the cyclic lactic acid oligomer can be dissolved and mixed in an organic solvent, or can be mixed under heat melting. It is possible, but not particularly limited. When a polylactic acid-based polymer is synthesized by directly dehydrating lactic acid from lactic acid in an organic solvent, a cyclic lactic acid oligomer can be simultaneously generated in a reaction solution and isolated as a mixture thereof.

The lactic acid-based polymer may be added with a generally known thermoplastic polymer or various modifiers to form a thermoplastic polymer composition. As the known thermoplastic polymer, a decomposable substance such as polyglycolic acid and polyε-caprolactone is preferable. The proportion of the lactic acid-based polymer in the thermoplastic polymer composition may be an arbitrary proportion depending on the intended degradability, but is generally preferably 50% or more. For the production of the thermoplastic polymer composition, all known kneading techniques can be applied, but the composition is used in the form of pellets, rods, powders and the like.

The thermoplastic composition obtained by the method of the present invention comprises:
It has the flexibility and strength required for films, yarns and packaging materials, especially food packaging materials or medical materials, is safe for food use and biocompatible, and can be used stably under various molding and use conditions. it can.

Hereinafter, the present invention will be described specifically with reference to examples.

[0024]

EXAMPLES Production Example 1 10.0 kg of 90% L-lactic acid at 150 ° C./50 mmHg
After distilling water while stirring for 3 hours, 6.2 g of tin powder was obtained.
Was added, and the mixture was further stirred at 150 ° C./30 mmHg for 2 hours to oligomerize. 28.8 g of tin powder was added to this oligomer.
And 21.1 kg of diphenyl ether,
An azeotropic dehydration reaction was carried out distill off water and the solvent was back separated in a water separator only solvent to the reactor at 35 mm Hg. After 2 hours, so as to return to the reactor the organic solvent back into the reactor through a column packed with molecular sieve 3A of 4.6 kg, an average molecular weight Mw = 110,000 performed 40 hours at 0.99 ° C. / 35 mm Hg Was obtained. 44 kg of dehydrated diphenyl ether was added to this solution, diluted at 100 ° C., cooled to 40 ° C., and the precipitated crystals were filtered, washed with 10 kg of n-hexane three times, and dried at 60 ° C./50 mmHg. 0.5 of this powder
N-HCl12. After adding 12.0 kg of ethanol and 12.0 kg of ethanol, the mixture was stirred at 35 ° C for 1 hour, and then filtered, and then 60 ° C / 50 m
After drying at mHg, 6.1 kg of polylactic acid powder (yield 85
%). The average molecular weight of the obtained polymer was Mw = 1.
It was 10,000. This powder was processed by a pelletizer to form a pellet and used in the following tests.

Preparation Example 2 10 kg (1.5 mol) of L-lactide, 0.01% by weight of tin octoate and 0.03% of lauryl alcohol
The polymerization% was sealed in a thick-walled cylindrical stainless steel polymerization vessel equipped with a stirrer, degassed under vacuum for 2 hours, and then replaced with nitrogen gas. The mixture is stirred for 200 hours under a nitrogen atmosphere.
Heated at C for 3 hours. While maintaining the temperature as it was, the air was gradually degassed by a vacuum pump through an exhaust pipe and a glass receiver to reduce the pressure in the reaction vessel to 3 mmHg. One hour after the start of degassing, the distillation of the monomer and low-molecular-weight volatile components disappeared. Therefore, the inside of the container was replaced with nitrogen, and the polymer was drawn out from the lower part of the container in a string form and pelletized to obtain poly L-lactic acid. This pellet is added to 65 kg of diphenyl ether
After dissolving at 00 ° C., the solution was cooled to 40 ° C., and the precipitated crystals were filtered, washed three times with 10 kg of n-hexane, and washed at 60 ° C.
/ 50 mmHg. This powder is mixed with 0.5N-HC
l12. kg and 12.0 kg of ethanol at 35 ° C
After stirring for 1 hour, the mixture was filtered and dried at 60 ° C./50 mmHg to obtain 9.1 kg of polylactic acid powder (yield: 91%). The average molecular weight of the obtained polymer was Mw = 110,0.
00. This powder was processed by a pelletizer to form a pellet and used in the following tests.

Production Example 3 10.0 kg of 90% L-lactic acid was replaced by 8.0 k of 90% L-lactic acid.
Production Example 1 except that g and 90% DL-lactic acid were changed to 20 kg.
Polymerization and pelletization were performed in the same manner as in the above to obtain polylactic acid. The molecular weight of this polymer was about 100,000.

Production Example 4 10.0 kg of 90% L-lactic acid was added to 9.0 kg of 90% L-lactic acid.
g and 70% glycolic acid were changed to 1.3 kg, and polymerization and pelletization were carried out in the same manner as in Production Example 1 to obtain a copolymer of L-lactic acid and glycolic acid. The molecular weight of this polymer is 10
It was 10,000.

Production Example 5 10.0 kg of 90% L-lactic acid was added at 150 ° C./50 mmHg.
After distilling water while stirring for 3 hours, 6.2 g of tin powder was obtained.
Was added, and the mixture was further stirred at 150 ° C./30 mmHg for 2 hours to oligomerize. 28.8 g of tin powder was added to this oligomer.
And 81.1 kg of diphenyl ether,
An azeotropic dehydration reaction was carried out distill off water and the solvent was back separated in a water separator only solvent to the reactor at 35 mm Hg. After 2 hours, so as to return to the reactor the organic solvent back into the reactor through a column packed with molecular sieve 3A of 4.6 kg, an average molecular weight Mw = 60,000 performed 40 hours at 130 ° C. / 15 mmHg Was obtained. The solution was concentrated to 70 kg, cooled to 40 ° C., and the precipitated crystals were removed by filtration to obtain a 59 kg filtrate.

The filtrate was concentrated to 5.8 kg, and 11.6 kg of n-hexane was added to separate the precipitated oily oligomer. This oily substance was treated with acetonitrile5.
The mixture was dissolved in 8 kg, and 5.8 kg of 1N hydrochloric acid was added. After stirring for 30 minutes, the upper light yellow oil layer was separated and washed with 5.8 kg of water. This oil layer was dissolved in 2.9 kg of chloroform, discharged into 50 l of isopropyl alcohol, and the precipitated crystals were filtered and dried to obtain 350 g of crystals.

The elemental analysis value of this crystal is represented by the composition formula C ₃ H ₄ O ₂
Calculated value when: C; 50.00%, H; 5.60
%; Measured values: C; 50.72%, H; 5.79%
Met.

FIG. 1 shows the result of mass spectrum analysis by the field desorption method. Structural unit C
_A peak is regularly shown at a position corresponding to an integer multiple of the molecular weight of ₃ H ₄ O ₂ , indicating a cyclic oligomer.

Further, ¹ H measured with a DMSO-d ₆ solvent was used.
FIG. 2 shows the NMR data.

Production Example 6 After distilling water while stirring 1.0 kg of 90% L-lactic acid at 150 ° C./50 mmHg for 3 hours, 0.6 g of tin powder was added, and the mixture was further stirred at 150 ° C./30 mmHg for 6 hours. And oligomerized. This oligomer was dissolved in 4.5 kg of acetonitrile, and 4.5 kg of 1N hydrochloric acid was added thereto to prepare 30
After stirring for 3 minutes, the upper light yellow oil layer was separated, and the
Wash with g. 2.3 kg of chloroform in the oil layer
Was dissolved in 4 l of isopropyl alcohol, and the precipitated crystals were filtered and dried to obtain 405 g of crystals.

FIG. 3 shows the result of mass spectrum analysis by the field desorption method. Structural unit C
_A peak is regularly shown at a position corresponding to the molecular weight obtained by adding 18 to an integral multiple of ₃ H ₄ O ₂ , indicating that the oligomer is a linear oligomer.

The average molecular weight (weight average molecular weight) of the polymer was measured by gel permeation chromatography using polystyrene as a standard under the following conditions.

Apparatus: Shimadzu LC-10AD Detector: Shimadzu RID-6A Column: Hitachi Chemical GL-S350DT-5, GL-S3
70DT-5 Solvent: chloroform Concentration: 1% Injection amount: 20 μl Flow rate: 1.0 ml / min Example 1 80 g of the polymer obtained in Production Example 1 and 20 g of the cyclic oligomer obtained in Production Example 5 were operated at 180 ° C. After homogenization in a closed mixer, the mixture was pelletized. This mixture was formed into a film having a thickness of 80 μm by a hot press at 160 ° C. A transparent and supple film was obtained. The average molecular weight measured by sampling a part of this film is 1
It was 10,000. The tensile strength of this film is 310 kg /
cm ² , and the elongation to break was 100% or more.

When the film was left in the air, the strength retention after 3 months was 100%.

Example 2 The polymer obtained in Production Example 2 and the cyclic oligomer obtained in Production Example 5 were mixed at a ratio of 80:20 and dissolved in chloroform to obtain a polymer solution having a concentration of 15%.
It was cast on a 150 mm glass plate to obtain a transparent and flexible film having a thickness of 40 μm. The tensile strength of this film is 300 kg / cm ² and the elongation to break is 1
More than 00%.

When the film was left in the air, the strength retention after one month was 100%.

Example 3 The polymer obtained in Production Example 3 and the cyclic oligomer obtained in Production Example 5 were mixed at 90:10, and dissolved in chloroform to form a polymer solution having a concentration of 15%.
It was cast on a 150 mm glass plate to obtain a transparent and flexible film having a thickness of 40 μm. The tensile strength of this film is 300 kg / cm ² and the elongation to break is 1
More than 00%.

When the film was left in the air, the strength retention after one month was 100%.

Example 4 The polymer obtained in Production Example 4 and the cyclic oligomer obtained in Production Example 5 were mixed at 90:10 and dissolved in chloroform to obtain a polymer solution having a concentration of 15%.
It was cast on a 150 mm glass plate to obtain a transparent and flexible film having a thickness of 40 μm. The tensile strength of this film is 280 kg / cm ² and the elongation to break is 1
More than 00%.

When the film was left in the air, the strength retention after one month was 100%.

Comparative Example 1 Instead of 20 g of the cyclic oligomer obtained in Production Example 5,
A transparent and flexible film having a thickness of 80 μm was obtained in the same manner as in Example 1 except that 20 g of L-lactide was used.
The tensile strength of this film is 290 kg / cm ² ,
The elongation to break was 100% or more.

When this film was left in the air,
Cloudy after week, touch and lost most strength after one month
Then the shape collapsed.

Comparative Example 2 A transparent and flexible film having a thickness of 80 μm was prepared in the same manner as in Example 1 except that the linear oligomer obtained in Production Example 6 was used instead of the cyclic oligomer obtained in Production Example 5. I got The average molecular weight measured by sampling a part of this film was 90,000. The tensile strength of this film is 250 kg / cm ² and the elongation to break is 100%
That was all.

When this film was left in the air,
After three months, when he lost his strength and touched, his shape collapsed.

[0048]

According to the present invention, the film, thread, packaging material, etc., that Ki particularly de be used for food packaging or medical applications, has flexibility, poly with sufficient stability under use conditions A thermoplastic composition containing lactic acid as a main component is obtained.

[Brief description of the drawings]

FIG. 1 is a mass spectrum of a cyclic oligomer of lactic acid produced in Production Example 5 by a field desorption method.

FIG. 2 is an NMR spectrum of a cyclic oligomer of lactic acid produced in Production Example 5.

FIG. 3 is a mass spectrum of a linear oligomer of lactic acid produced in Production Example 6 by a field desorption method.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-177734 (JP, A) JP-A-4-283227 (JP, A) Patent 3167411 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 67/04

Claims (5)

(57) [Claims] 1. A thermoplastic polymer composition comprising polylactic acid or a copolymer of lactic acid and another hydroxycarboxylic acid as a main component, comprising a cyclic oligomer of lactic acid as a plasticizer (however,
And the porous film-like thermoplastic polymer listed below.
-Composition and polymer network heat listed below
Excluding plastic polymer compositions. Polylactic acid (A) or
Is a lactic acid-hydroxycarboxylic acid copolymer (B) 80-
100% by weight and 0 to 20% by weight of the plasticizer (C)
With respect to 100 parts by weight of the polylactic acid-based resin composition containing
Fine powder filler (D) having a diameter of 0.3 to 4 µm, 40 to 250
After melt-forming the mixture to which parts by weight have been added, at least
Porosity characterized by being stretched 1.1 times or more in uniaxial direction
A functional film-like thermoplastic polymer composition comprising polylactic acid
The acid (A) contains 85 to 100 mol% of L-lactic acid units and D-
0-15 mol% of lactic acid units or 85-D-lactic acid units
100 mol% and 0 to 15 mol% of L-lactic acid unit.
Lactic acid-hydroxycarboxylic acid copolymer (B)
-85 to 100 mol% of lactic acid units or D-lactic acid units
85 to 100 mol% and glycolic acid unit 0 to 15 mol
% Plasticizer (C) and the lactic acid oligomer or lactide
Pide, and the fine powder filler (D) is an inorganic fine powder
A porous film-like thermoplastic polymer composition which is:
Polylactic acid (A) or lactic acid-hydroxycarboxylic acid copo
80-100% by weight of rimer (B) and plasticizer
(C) Polylactic acid resin composition 10 containing 0 to 20% by weight
0.2 to 10 parts by weight of a foaming agent was added to 0 parts by weight.
A polymer network formed by melt-blowing extrusion of the mixture and opening.
A thermoplastic polymer composition, wherein the polylactic acid (A) is L
-85 to 100 mol% of lactic acid units and 0 to D-lactic acid units
15 mol% or D-lactic acid unit 85 to 100 mol%
And L-lactic acid units containing 0 to 15 mol% of L-lactic acid units,
The loxycarboxylic acid copolymer (B) contains 85 L-lactic acid units.
~ 100 mol%, or 85-100 mol of D-lactic acid unit
% And glycolic acid units from 0 to 15 mol%, and
The plasticizer (C) is a lactic acid oligomer or lactide .
Polymer network-like thermoplastic polymer composition. ) . 2. A lactic acid cyclic oligomer is contained as a plasticizer.
Of polylactic acid or lactic acid and other hydroxycarboxylic acids
Thermoplastic polymer composition containing copolymer as a main component (however,
And the thermoplastic contained in the porous film listed below
Polymer composition and polymer networks listed below
Excluding the thermoplastic polymer composition contained in the solid. Po
Lilactic acid (A) or lactic acid-hydroxycarboxylic acid copoly
80-100% by weight of mer (B) and plasticizer (C)
100% by weight of a polylactic acid-based resin composition containing 0 to 20% by weight
Parts, a fine powder filler having an average particle size of 0.3 to 4 μm
(D) Melt casting of a mixture to which 40 to 250 parts by weight is added
And then stretched at least 1.1 times in the uniaxial direction.
A porous film characterized by the following:
(A) 85 to 100 mol% of L-lactic acid unit and D-milk
Acid unit 0 to 15 mol% or D-lactic acid unit 85-1
00 mol% and 0-15 mol% of L-lactic acid units,
Lactic acid-hydroxycarboxylic acid copolymer (B) is L-milk
85 to 100 mol% of acid units or 85 of D-lactic acid units
-100 mol% and glycolic acid unit 0-15 mol%
And the plasticizer (C) is a lactic acid oligomer or lactide
And the finely divided filler (D) is an inorganic fine powder.
Porous film. Polylactic acid (A) or Lactic acid-H
Droxycarboxylic acid copolymer (B) 80 to 100 weight
% And a plastic milk containing 0 to 20% by weight of a plasticizer (C)
Blowing agent 0.2 to 1 per 100 parts by weight of acid-based resin composition
0 parts by weight of the mixture is melt foamed and extruded, and
Wherein the polylactic acid (A) is L-lactic acid
85-100 mol% of units and 0-15 mol of D-lactic acid units
% Or D-lactic acid units of 85 to 100 mol% and
L-lactic acid containing 0 to 15 mol% of lactic acid-hydroxy
The carboxylic acid copolymer (B) has an L-lactic acid unit of 85 to 10
0 mol%, or 85-100 mol% of D-lactic acid units.
And 0 to 15 mol% of glycolic acid units, and
The plasticizer (C) is a lactic acid oligomer or lactide.
Child reticulum. ) . Wherein lactic acid is L- lactate, D- lactic acid or claim 1 or 2 in serial <br/> mounting of the composition characterized in that it is a mixture thereof. 4. Hydroxycarboxylic acid is glycolic acid,
4. The composition according to claim 1 , wherein the composition is 6-hydroxycaproic acid. 5. The cyclic oligomer of lactic acid is represented by the following general formula:
(1) (Formula 1), characterized in that it is represented as being in claims 1 or composition according to any one of the 4. Embedded image (In the formula, n represents 3 to 200.)