JPH09137047A - Plasticized aliphatic polyester composition and its molding product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the above new naturally degradable composition, improved in mechanical properties and transparency and useful for fibers, etc., by using a segment of a high-melting polymer consisting essentially of a specific aliphatic polyester. SOLUTION: This plasticized aliphatic polyester composition comprises a mixture of a block copolymer containing a segment of (A) a high-melting polymer consisting essentially of an aliphatic polyester having <=150 deg.C melting point bonded to a segment of (B) a low-melting polymer consisting essentially of an aliphatic polyester having <=130 deg.C melting point or (D) its oligomer with at least one polymer or its oligomer selected from the group of (E) a block copolymers at copolymerization ratios different from that of the components (A), (B) and (C). The weight of the component (B), it oligomer and segment thereof accounts for 3-60wt.% of the total weight and the weight of the oligomer accounts for <=50wt.% of the total weight. The weight ratio of the segment of the component (A) to the segment of the component (B) is preferably within the range of (5/95) to (95/5).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel plasticized aliphatic polyester composition and a molded article thereof.

[0002]

2. Description of the Related Art At present, synthetic resins, which are consumed in large quantities as fibers, films and various molded products, have a very slow decomposition rate in a natural environment, and when they are incinerated, they generate a large amount of heat and damage the furnace. , It is necessary to review it from the viewpoint of protecting the natural environment. Aliphatic polyesters are generally spontaneously degradable, but low-melting point aliphatic polyesters having a melting point of 150 ° C. or less have a problem in practical use in terms of heat resistance. On the other hand, high melting point aliphatic polyesters having a melting point of 150 ° C. or higher include polyglycolic acid (melting point of about 230 ° C.) and polylactic acid (melting point of about 175 ° C.).
C.), polyhydroxybutyrate (melting point: about 180.degree. C.) and copolymers containing them as the main component are known, but they have high crystallinity and a rigid molecular structure.
It has the drawback of being rigid and brittle, and its improvement, namely plasticization (softening), is necessary.

In order to improve the above drawbacks of the high melting point aliphatic polyester, it is considered to mix a soft low melting point aliphatic polyester or an oligomer thereof as a plasticizer, and it is proposed in JP-A-7-118513. However, in general, different polymers tend to have poor compatibility or miscibility, and particularly, the miscibility of the high-melting point aliphatic polyester and the low-melting point aliphatic polyester is not so good, and for example, the impact resistance of the mixture is expected. There is a problem that the mixture is not improved so much and the mixture tends to become cloudy. In the above-mentioned Japanese Patent Laid-Open Publication, in order to improve the compatibility, the end of the low melting point aliphatic polyester (oligomer) used as a plasticizer is blocked with a monobasic acid or a monovalent alcohol. However, in this method, end-capping is considerably difficult and the cost is high, and the compatibility is not sufficiently improved. In the examples of the above-mentioned Japanese Patent Laid-Open Publications, a kneading method using a plurality of rolls is shown as a mixing method, but it is preferable from a practical point of view that it can be easily and uniformly mixed with a screw extruder or the like which is simpler and more efficient. .

[0004]

DISCLOSURE OF THE INVENTION The object of the present invention is that it is naturally degradable and preferable from the standpoint of environmental protection. It has improved heat resistance, flexibility, impact resistance and transparency, and is easy to use in, for example, a screw extruder. Disclosed is a novel aliphatic polyester composition having remarkably improved miscibility and a molded article thereof, which can be uniformly mixed with each other.

[0005]

The above object of the present invention is achieved by a plasticized aliphatic polyester composition which is characterized by satisfying all the following items (1), (2) and (3). To be done. (1) A segment of a high-melting polymer (A) having a melting point of 150 ° C. or higher as a main component, and a segment of a low-melting polymer (B) having a melting point of 130 ° C. or less as a main component And a block copolymer (C) or an oligomer (D) thereof bonded to [a high-melting point polymer (A), a low-melting point polymer (B), and a different copolymerization ratio from the block copolymer (C)] The block copolymer (E)] is a mixture with at least one kind of polymer selected from the group or oligomers thereof.

(2) The weight of the low melting point polymer (B), its oligomer and its segment accounts for 3 to 60% of the total weight.

(3) The weight of the oligomer is 50% or less of the total weight.

Here, the polymer containing an aliphatic polyester as a main component means (1) an aliphatic hydroxycarboxylic acid such as glycolic acid, lactic acid or hydroxybutylcarboxylic acid, (2) glycolide, lactide or butyrolactone,
Aliphatic lactones such as caprolactone, (3) ethylene glycol, propylene glycol, butanediol,
Aliphatic diols, such as hexanediol, (4)
Aliphatic polyether glycols such as diethylene glycol, triethylene glycol, ethylpropyl ether glycol, bishydroxyethylpropane, bishydroxypropylbutane, polyethylene glycol, polypropylene glycol, polybutylene ether, copolymers thereof and oligomers thereof,
(5) Aliphatic polycarbonate glycols such as dihydroxybutyl carbonate, dihydroxyhexyl carbonate, polybutylene carbonate (glycol), polyhexane carbonate (the same), polyoctane carbonate (the same), copolymers and oligomers thereof,
(6) A main component, that is, 50% by weight or more (particularly 60% or more) of a component derived from an aliphatic polyester polymerization raw material, such as an aliphatic dicarboxylic acid such as succinic acid, adipic acid, or sebacic acid. , Homopolymer of aliphatic polyester, copolymer of aliphatic polyester,
And other components such as aromatic polyester, polyether, polycarbonate, polyamide, polyurea, polyurethane, polyorganosiloxane and the like in the aliphatic polyester, 50% by weight or less (particularly 40% or less) copolymerization (block copolymerization, Graft copolymerization, or / and random copolymerization) or / and mixed modified products are all included.

The purpose of modifying the aliphatic polyester by copolymerization or mixing is to lower the crystallinity, lower the melting point (lower the polymerization temperature, molding temperature, processing temperature), melt fluidity, toughness, flexibility and elastic recovery. Improved, friction coefficient, surface roughness,
Examples thereof include a decrease or increase in adhesiveness, heat resistance and glass transition temperature, improvement of gas barrier property, moisture permeability, hydrophilicity and water repellency, improvement of dyeability, improvement or suppression of decomposability.

The characteristic of the aliphatic polyester is that it decomposes in a relatively short period (for example, within 5 years, especially within 2 years) under a natural environment (in soil, fresh water, seawater, in compost, etc.). This spontaneous degradability is maintained even in a copolymer or mixture containing an aliphatic polyester as a main component, but various decomposition rates can be obtained by changing the components or ratio of the copolymerization or the mixture. You can select the appropriate one according to your application.

In the present invention, the oligomer has a degree of polymerization of 2 to
It means less than 20. Similarly, in the present invention, a segment means a part of a polymer molecular chain,
The degree of polymerization is from 2 to less than 20 and the degree of polymerization is 2
Includes both polymer grades of 0 or higher.

The high melting point polymer (A) is a main component of the composition of the present invention and is a skeleton component which maintains strength and heat resistance. The high-melting-point polymer (A) is an aliphatic polyester having a melting point of 150 ° C. or higher, for example, a homopolymer such as polyglycolic acid, polylactic acid, polyhydroxybutyrate, and the like, while maintaining the melting point of 150 ° C. or higher. It is a copolymer of a component and a third component.

The low melting point polymer (B) is a plastic component which imparts preferable flexibility, toughness, impact resistance, elongation and moldability to the composition of the present invention. However, if the high-melting polymer (A) is simply mixed with the low-melting polymer (B), the effect is small due to insufficient compatibility as described above, and there is a problem that the transparency is lowered (white turbidity). In order to solve this problem, the present inventors have diligently studied to improve the affinity of both components,
The present invention has been completed.

Preferred examples of the homopolymer of the aliphatic polyester having a melting point of 150 ° C. or lower for the purpose of the present invention include polycaprolactone (melting point of about 60 ° C.), polyethylene adipate (44 ° C.) and polyethylene suberate (64 same).
° C), polyethylene sebacate (at 72 ° C), polyethylene decamylate (at 85 ° C), polybutylene succinate (at 116 ° C), polybutylene adipate (at 6 ° C).
9 ° C.), polybutylene sebacate (65 ° C. same), polyhexamethylene sebacate (75 ° C. same) and the like. Of course, aliphatic polyesters having a melting point of 150 ° C. or less other than those exemplified here, such as polyester ethers which are condensation products of diethylene glycol and adipic acid and triethylene glycol and sebacic acid, are also useful in the present invention. Also, copolymers containing these polyesters as components,
Copolymers of these polyesters with other components are also useful. Generally, homopolymers and their main components (eg 9
Most of the copolymerized polymers (0% or more) are crystalline and quickly solidify when cooled to a temperature equal to or lower than the melting point, which facilitates production and handling and is preferable as a plastic component. In particular, a crystalline polymer having a relatively high melting point (melting point of 75 ° C. or higher, particularly 85 ° C. or higher), such as polyhexamethylene sebacate, poly (ethylene decamethylate), polybutylene succinate, etc., is preferable because it increases the heat resistance of the product. .
If the polymer is crystalline, it exhibits a clear (eg, endothermic amount of 10 J / g or more, particularly 20 J / g or more) melting endothermic peak in DSC analysis.

On the other hand, as the low melting point polymer (B), those having a low crystallinity or an amorphous one are also useful because they have excellent plasticity and flexibility. The melting point of an amorphous material is not clear, but the temperature at which the melt viscosity reaches 100,000 poise is the melting point here.

The first group of preferred embodiments of the present invention is to plasticize a block copolymer (C) of a high melting point homopolymer (A) and a low melting point homopolymer (B) into a high melting point polymer (A). It is a mixture [A + C] as an agent.
In this case, the matrix (matrix) polymer (A) is incorporated as a segment in the block copolymer (C) which is a plasticizer, and the affinity between the matrix and the plasticizer is significantly improved. This affinity is higher as the amount of the high melting point polymer (A) segment in the block copolymer (C) is larger. On the other hand, the plasticizing effect is more remarkable as the amount of the low melting point polymer (B) in the block copolymer (C) is larger and the amount of the block copolymer (C) which is a plasticizer is larger. . Therefore, depending on the purpose of use, the weight ratio (A / B) of the high melting point polymer (A) and the low melting point polymer (B) in the block copolymer (C) and the block copolymer (C) Just select the addition rate. The copolymerization ratio (A / B) is in the range of about 3/97 to 50/50, especially 5/95 to 30.
In most cases, about / 70 is preferable. Even if the block copolymer (C) is replaced with its oligomer, a similarly good composition can be obtained.

As a specific example, polylactic acid is used as the high melting point polymer (A), while polycaprolactone / polylactic acid (for example, a weight ratio of 80/20) block copolymer (C) is used as a plasticizer. 5-50%, especially 10-
Mixing 30% gives a good plasticized polylactic acid composition.

The second group of the preferred embodiments of the present invention is a mixture of a high melting point homopolymer (A), a low melting point homopolymer (B) and both block copolymers (C) [A + B + C]. ]. In this composition, (A) is a skeleton, (B) is a plasticizer,
(C) is a kind of surfactant that improves the miscibility of both. In this case, the block copolymer (C) has a copolymerization ratio (A / B) of 10/90 to 90/10, particularly 70/3.
A range of 0-30 / 70 is often preferred. The addition rate of the plasticizer (B) is preferably, for example, 3 to 45%, particularly preferably 5 to 30%. Similarly, the addition rate of the miscibility improver (C) is often, for example, preferably 3 to 30%, particularly preferably 5 to 20%. The low melting point homopolymer (B) and / or the block copolymer (C) can be replaced with the oligomer.

As a specific example, polylactic acid is used as the high melting point polymer (A) and the polycaprolactone (hereinafter referred to as P)
5) as a low melting point polymer (B).
-30% and both 1/1 block copolymers (C) are mixed as a miscibility improver in an amount of 5-20% to obtain a preferred plasticized polylactic acid composition.

The third group of preferred embodiments of the present invention comprises a block copolymer (C) of a high melting point homopolymer (A) and a low melting point homopolymer (B), and a low melting point polymer (B). It is a mixture [C + B]. in this case,
The main component of the block copolymer (C) is a high melting point polymer (A)
And the segment of the low melting point polymer (B) is bonded thereto. The low melting point polymer (B) is a plasticizer and can be replaced with an oligomer.

As a specific example, polylactic acid having a block copolymer of 5 to 20% PCL (C) and PCL
A mixture with (B) in a ratio (C / B) of 95/5 to 70/30 can be mentioned. PCL in the block copolymer (C)
The higher the segment ratio, the stronger the affinity with the plasticizer PCL (B). Further, the larger the mixing ratio of the plasticizer PCL (B), the more remarkable the plasticizing effect.

The fourth group of the preferred embodiments of the present invention comprises a block copolymer (C) of a high melting point homopolymer (A) and a low melting point homopolymer (B), and also a high melting point homopolymer (A). It is a mixture [C + E] of a block copolymer with the low melting point homopolymer (B) and a block copolymer having a different copolymerization ratio (E). Here, one (C) of the block copolymer is a skeleton component having a high melting point homopolymer as a main component (50% or more), and the other (E) of the block copolymer is a low melting point homopolymer as a main component (50%). %) Or more) and a combination with a plastic component. In this combination, both polymers contain the same components (segments) as the mixing partner, and the highest affinity is achieved.

Specific examples include polylactic acid in which 3 to 20% of PCL is block-copolymerized (C) and PCL of 3 to
Ratio (C / E) 97/3 to 70/30, especially 95 / with 20% polylactic acid block copolymerized (E)
A mixture of 5 to 80/20 can be mentioned.

The above-mentioned first to fourth groups specifically show preferred embodiments of the present invention, and the present invention is not limited to them. In the specific examples of the first to fourth groups of the preferred embodiments of the present invention, only polylactic acid is used as the high melting point homopolymer (A), and polycaprolactone (PC) is used as the low melting point homopolymer (B).
Although only L) is shown, similar effects can be obtained by replacing them with other high melting homopolymers or other low melting homopolymers. Similarly, instead of the pomopolymer, a copolymer having it as a main component can be substituted. The plasticizer and the miscibility improver may be a polymer or an oligomer, and the oligomer and the polymer may be used together (mixed). Generally, the oligomer type plasticizer has a high plasticizing effect, and the polymer type plasticizer has excellent stability of the mixture.
Therefore, the molecular weights and addition rates of the skeleton component and the plastic component (polymer, oligomer, segment) may be selected according to the purpose of use.

As described above, the composition of the present invention comprises a high melting point aliphatic polyester component which is a skeleton and a low melting point aliphatic polyester component which is a plasticizer. In order to obtain the required plasticizing effect, the total weight of the plastic component, ie the low melting point aliphatic polyester (B), its oligomers and its segments, must be in the range 3-60% of the total weight of the composition, The range of 5 to 50% is preferable, and 8 to 40%
Is most widely used. This is because if the amount of the plastic component is too small, the plasticizing effect is insufficient, and if it is too large, the heat resistance is insufficient.

The oligomer has a high effect when it is used as a plasticizer, but if too much is used, the strength and heat resistance of the composition tend to be lowered. Therefore, the oligomer is effective and widely applicable to the low melting point aliphatic polyester (B) and the block copolymer (E) containing the same as the main component, which are used as a plasticizing component or an affinity improver, but the skeleton component is It is not suitable for the high melting point aliphatic polyester (A) and the copolymer containing it as the main component. That is, the content of the oligomer needs to be 50% or less, preferably 40% or less, and more preferably 30 to 0% of the total weight of the composition.

The terminals of the polymer and oligomer constituting the composition of the present invention may be functional groups such as carboxylic acid group and hydroxyl group, but may be blocked or substituted with an alkyl group or other groups. In general, plasticizers, particularly oligomers, tend to be inferior in stability, and thus those in which the terminal functional group is blocked with an aliphatic monobasic acid or an aliphatic monoalcohol are often preferred. Similarly, a hydroxyl group, which is particularly inferior in stability, can be blocked by reacting it with a monoisocyanate or a diisocyanate.

The block copolymer, which is an important component of the composition of the present invention, can be produced by block copolymerization in the polymerization step. For example, in the step of producing polylactic acid by melt-polymerizing lactide, by reacting PCL having a hydroxyl group at one end or both ends, a polylactic acid / PCL block copolymer can be obtained. An AB type block copolymer can be obtained by using a low melting point polyester (or an oligomer thereof) having a hydroxyl group at one end, and an ABA type block copolymer can be obtained by using a low melting point polyester having a hydroxyl group at both ends. However, it is desirable that the water content of the reaction system is 100 ppm or less and the reaction time is short to prevent random copolymerization due to transesterification reaction. Similarly, when melt-polymerizing glycolide to produce polyglycolic acid, it is possible to block-copolymerize the low-melting point aliphatic polyester. Of course, as the low-melting point aliphatic polyester, other than PCL, those having a hydroxyl group can be similarly easily block-copolymerized.

Another method of block copolymerization is a high melting point aliphatic polyester (or oligomer) having a terminal functional group.
And a low-melting point aliphatic polyester (or oligomer) having a functional group at the terminal, are reacted with a polyfunctional compound to bond the both. For example, the terminal hydroxyl group can be reacted with dicarboxylic acid, dicarboxylic acid anhydride, dicarboxylic acid chloride, diisocyanate or the like as a joint. Similarly, the terminal amino group may be reacted with a dicarboxylic acid, a dicarboxylic acid derivative, diisocyanate or the like as a joint. Similarly, a terminal carboxyl group can be reacted with a diamine, a diol, or the like. This method can be applied to all combinations, for example, the production of a block copolymer of polyhydroxybutyrate and a low melting point aliphatic polyester.

The composition of the present invention is a mixture of at least two polymers or / and oligomers. The mixing method is not particularly limited, but for example, a screw extruder, 2
Mechanical stirring with a shaft kneading extruder, a kneader, a gear pump, a kneading roll, a tank having a stirrer, etc. may be used, and a static mixer that repeats branching and merging by a flow guiding device may be applied, or they may be used together. Good. The mixing may be performed by a batch method or a continuous method, but of course, a continuous method, for example, a screw extruder, a twin-screw kneading extruder, a static mixer, or the like is preferable because of high efficiency. The mixing may be performed, for example, in the polymerization step, and may be performed after the polymerization step and before or during the molding step.

For example, if a low-melting point aliphatic polyester having a terminal blocked and a low-melting point aliphatic polyester having a hydroxyl group at the terminal are mixed and supplied to a melt polymerization system of lactide, the low-melting point fatty acid having a hydroxyl group at the terminal is mixed. The group polyester reacts with lactide to form a block copolymer, and the low-melting point aliphatic polyester whose end is blocked remains unreacted, and the composition of the present invention in which both are mixed can be produced in one step, and its continuation is also possible. It is possible.

The composition of the present invention contains a pigment, if necessary.
Colorants such as dyes, inorganic or organic particles, glass fibers, whiskers, fillers such as mica, crystal nucleating agents, antioxidants, stabilizers such as UV absorbers, lubricants, release agents, water repellents, A plasticizer, an antibacterial agent and other secondary additives can be added.

[0033]

EXAMPLES In the following examples,% and parts are by weight unless otherwise specified. The molecular weight of the aliphatic polyester is
In GPC analysis of a 0.1% chloroform solution of a sample, it is a weight average value of dispersion of a high molecular component excluding components having a molecular weight of 500 or less. The DSC measurement was performed under the conditions of a sample 10 mg, a nitrogen atmosphere, and a temperature rising rate of 10 ° C./min.
The impact strength was measured according to JIS K 7110 by making a V-shaped notched test piece from a sample polymer with an injection molding machine.
It was measured by the Izod impact test method.

Example 1 95 parts of L-lactide having an optical purity of 99.5% or more, 5 parts of PCL having a molecular weight of 155,000 (weight average molecular weight of 70,000) and a hydroxyl group at one end, polymerization catalyst tin octylate 100 pp.
m was continuously supplied to a twin-screw kneading extruder, reacted at 195 ° C. for an average of 18 minutes, extruded from a die, cooled in water, and then cut and dried to obtain a chip C1. Chip C
1 was heated (solid phase polymerization) in a nitrogen stream at 140 ° C. for 4 hours to obtain a polymer P1.

Polymer P1 was poly L-lactic acid in which PCL was block-copolymerized at about 5% and had a molecular weight of 175,000 and a melting point of 172 ° C. Although the molecular weight of the PCL segment in the polymer P1 is not clear, it is presumed that the PCL segment is partially hydrolyzed during the copolymerization and is lower than the molecular weight of the starting PCL. By DSC analysis and GPC analysis, (unreacted) PCL was not found in the polymer P1, mechanical properties were superior to the mere mixture, and the melting point was slightly lowered by the copolymerization. Polymer P1 is found to be substantially a polylactic acid / PCL block copolymer.

Almost the same as Polymer P1, except PC
Poly L-lactic acid homopolymer obtained without copolymerizing L
Let it be 2. The polymer P2 had a molecular weight of 195,000 and a melting point of 173 ° C. Almost the same as the polymer P1,
However, a polymer obtained by mixing 95 parts of PCL, 5 parts of L-lactide, and 20 ppm of tin octylate and polymerizing in the same manner is referred to as P3. The polymer P3 is a PC in which about 5% of poly L-lactic acid semae having a molecular weight of about 3500 is block-copolymerized.
In L, the molecular weight was 153000, the melting point was 58 ° C., and the melting endotherm was 45 J / g.

Polymer P1 (chip) 90 parts, molecular weight 1
Mix 55,000 of the above PCL (chip) with 10 parts and mix
A shaft kneading extruder continuously melt-mixed at 210 ° C., extruded from a die and cooled and cut to obtain a mixed polymer MP1. 90/1 of polymer P2 and polymer P3 obtained in the same manner
The mixed polymer of 0 is designated as MP2, and the 90/10 mixture of polymer P1 and polymer P3 is designated as MP3. For comparison, 90/1 of polymer P2 and PCL obtained in the same manner
Let the mixture of 0 be MP4.

Mixed Polymers MP1, MP2, MP3, M
P4 and unmodified polylactic acid P2 were used to prepare test pieces for a mechanical performance test by an injection molding machine, and tensile strength, bending strength and impact strength were measured. Further, the transparency of the test piece was visually evaluated. The measurement and evaluation results are shown in Table 1.
As can be seen from the table, the composition of the present invention is remarkably excellent in elongation, impact strength, transparency and the like as compared with the unmodified product of the comparative example and the simple mixed product.

[0039]

[Table 1] Example 2 A block copolymer obtained in the same manner as the polymer P1 of Example 1 except that 5% of polybutylene succinate (hereinafter referred to as PBS) having a molecular weight of 126000 and a hydroxyl group at one end was copolymerized with lactide. Combined, molecular weight 17300
Polymer P4 having a melting point of 0 and a melting point of 173 ° C. is referred to as polymer P4.

A block copolymer obtained in the same manner except that the lactide / PBS ratio was 50/50 and the reaction time was 30.
Minutes, polymer P having a molecular weight of 83,000
5 is assumed.

A mixed polymer MP5 was obtained in the same manner as the mixed polymer MP1 of Example 1, except that the above polymer P4 and PBS were mixed at a ratio of 90/10. Similarly, the polymer P1 of Example 1, the PBS and the polymer P5 were mixed at a ratio of 90/10/5 to obtain a mixed polymer MP.
6 was obtained. For comparison, the polymer P1 and PBS were mixed in a ratio of 90/10 in the same manner to prepare a mixed polymer MP.
7 was obtained.

Mixed Polymers MP5, MP6 and MP7
A test piece was prepared in the same manner as in Example 1, the mechanical properties were measured, and the transparency was evaluated. Table 2 shows the results. As can be seen in Table 2, the composition of the present invention had excellent mechanical properties and transparency.

[0043]

[Table 2]

[0044]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a novel polymer composition which is naturally degradable and has improved mechanical properties and transparency, which is suitably used in many applications and contributes greatly to the protection of the natural environment. There is expected. That is, although the heat resistance is excellent, the drawback of the high melting point aliphatic polyester that is rigid and brittle is greatly improved by increasing the affinity with the plasticizing component, and excellent impact resistance, elongation, flexibility and transparency. , Heat resistance, etc. are realized. Further, these plasticizing effects can be adjusted largely and arbitrarily by changing the ratio of plasticizing components, and can be preferably applied to various uses.

The composition of the present invention comprises fibers, knits, woven fabrics, non-woven fabrics, papers, nets, ropes, cords, sheets, films, boards,
It can be used for rods, tubes, various containers, bags, plates, tableware, various parts and other various molded products.

Claims (3)

[Claims] 1. A plasticized aliphatic polyester composition characterized by satisfying all of the following items (1), (2) and (3). (1) A segment of a high melting point polymer (A) containing an aliphatic polyester as a main component and having a melting point of 150 ° C. or higher, and a melting point of 130.
A block copolymer (C) or an oligomer (D) thereof in which a segment of a low melting point polymer (B) having an aliphatic polyester as a main component at a temperature of not higher than 0 ° C. is bonded, and a [high melting point polymer (A), low The melting point polymer (B) and at least one polymer selected from the group of block copolymers (E) having a copolymerization ratio different from that of the block copolymer (C)] or a mixture with an oligomer thereof. . (2) The weight of the low melting point polymer (B), its oligomer and its segment accounts for 3 to 60% of the total weight. (3) The weight occupied by the oligomer is 50% or less of the total weight. 2. The weight ratio of the high melting point polymer (A) segment and the low melting point polymer (B) segment constituting (1) the block copolymers (C), (E) and their oligomers is 5 / 95 to 95-5, and (2) the low melting point polymer (B), its oligomer and its segment weight account for 5 to 50% of the total weight. Stuff. 3. Fibers, threads, ropes, knits, woven fabrics, non-woven fabrics comprising the aliphatic polyester composition according to claim 1.
Paper, film, sheet, board, rod, tube, various containers,
Bags, various parts, and various molded products.