JPH09100344A - Polyactic acid block copolymer composition, its production and its molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyactic acid copolymer having flexibility while retaining crystallinity and heat resistance by bonding an amorphous segment based on at least two compounds such as aliphatic dicarboxylic acids to a crystalline segment of an L- or D-lactic acid homopolymer. SOLUTION: A new polylactic acid block copolymer prepared by bonding an amorphous segment (B) based on at least two members selected from among aliphatic dicarboxylic acids, linear diols, 3C or higher lactones and 4C or higher hydroxyalkylcarboxylic acids to a crystalline segment (A) comprising a polymer substantially entirely consisting of units of L- or D-lactic acid. It is desirable that segment A as a hard segment having crystallinity and heat resistance has the highest possible purity (the second component <3mol%). It is desirable that segment B needs containing 50wt.% or above, in total, above four components and being made from multiple components for the sake of developing flexibility and having no melting point. The polyactic acid copolymer is easily obtained by forming a B-forming polymer and subjecting this polymer and an L- or D-lactide to a ring opening polymerization reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to crystallinity, heat resistance,
The present invention relates to a novel polylactic acid block copolymer composition excellent in flexibility and toughness, a method for producing the same, and a molded product thereof.

[0002]

2. Description of the Related Art Polymers that are biodegradable or decompose in a natural environment have been attracting attention from the viewpoint of environmental protection. Among them, polylactic acid is excellent in cost and performance using agricultural products as raw materials, and is expected as the most practical biodegradable polymer. However, since polylactic acid has a rigid molecular structure and high crystallinity, it has the drawback that molded products are hard and brittle. Therefore, it has been attempted to suppress the crystallinity by copolymerization and improve the flexibility and toughness. As one of the methods, copolymerization with a polyester polymerization raw material other than lactic acid can be considered.

[0003]

However, in the random copolymerization which is usually carried out, there is a big problem that flexibility and toughness are improved to some extent but crystallinity is lost and only poor heat resistance can be obtained. The inventors of the present invention have earnestly studied for the purpose of improving flexibility and toughness while maintaining preferable crystallinity and heat resistance of polylactic acid, and arrived at the present invention.

[0004]

[Means for Solving the Problems]
The above object of the present invention is to provide a crystalline segment (A) comprising a substantially homopolymer of poly-L-lactic acid or poly-D-lactic acid.
And "an aliphatic dicarboxylic acid, a chain diol, a lactone having 3 or more carbon atoms (hereinafter referred to as carbon number), and a carbon number of 4"
Achieved by a novel polylactic acid block copolymer composition in which an amorphous segment (B) containing at least two compounds selected from the group of the above “hydroxyalkylcarboxylic acid” as a main component is bonded. Found.

Here, the segment means a part of a polymer molecular chain. The substantially homopolymer of poly L-lactic acid or poly D-lactic acid forming the segment (A) is poly L-lactic acid.
-Lactic acid homopolymer, poly D-lactic acid homopolymer, and those obtained by copolymerizing them with a small amount of other components that do not impair the melting point and crystallinity. For example, even if about 1 to 3% by weight of D-lactic acid component is copolymerized with poly L-lactic acid homopolymer, the melting point is slightly decreased (10 ° C).
C or less), which is considered to be substantially a homopolymer. The same applies when another ester bond-forming component is copolymerized as a small amount of another component. However, when the D-lactic acid component is copolymerized with poly L-lactic acid in an amount of, for example, more than 5%, the melting point is lowered by 20 ° C or more, and it cannot be said that it is substantially a homopolymer. Above, especially 6 mol%
Even if the second component is mixed as described above), the heat resistance of the product tends to be impaired due to the deterioration of crystallinity and should be avoided as much as possible. That is, the segment (A) is a kind of hard segment, which is preferably highly crystalline and highly pure, and the copolymerization ratio of the second component is 5% or less, particularly 4% or less, and most preferably 3% or less. . Therefore, it is preferable to increase the purity of the polymerization raw material, to keep the polymerization reaction at the lowest possible temperature for a short time, and to prevent racemization (formation of optical isomers) during the reaction.

The polymer forming the segment (B) is
Amorphous containing at least two compounds selected from the group of "aliphatic dicarboxylic acid, chain diol, lactone having 3 or more carbon atoms, and hydroxyalkylcarboxylic acid having 4 or more carbon atoms" as a main component ( Amorphous).
The aliphatic dicarboxylic acid is preferably saturated or unsaturated, has a straight chain type or a side chain and has about 4 to 20 carbon atoms, and for example, succinic acid, adipic acid, suberic acid,
Saturated forms such as azelaic acid, sebacic acid and decanedicarboxylic acid are particularly preferred.

The chain diol is a diol having no aromatic nucleus or alicyclic nucleus, and is an aliphatic diol, an oligomer of polyalkylene ether, an oligomer of polyalkylene carbonate or an oligomer of polyorganosiloxane having both hydroxyl groups at both ends. Include. As the aliphatic diol, a diol having a straight chain or a side chain having about 2 to 20 carbon atoms such as ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol and decanediol is preferable. Similarly, examples of preferred oligoalkylene ethers include diethylene glycol, triethylene glycol, polyethylene glycols having a molecular weight of 5000 or less, especially 2000 or less, polypropylene glycol, polybutylene ether, and copolymers thereof such as ethylene glycol / propylene glycol copolymers. Examples include polymers and oligomers of ethylene glycol / butylene glycol copolymers. Similarly, a copolymerized alkylene ether oligomer obtained by addition-reacting ethylene oxide or propylene oxide with an aliphatic diol such as butanediol or hexanediol is also useful as a component of the segment (B) in combination with a dicarboxylic acid. Is. Similarly, an oligomer of polyalkylene carbonate such as polybutylene carbonate or polyhexane carbonate, or an oligomer of polyorganosiloxane such as polydimethylsiloxane, polydiethylsiloxane or polydiphenylsiloxane (for example, a molecular weight of about 2000 or less) has hydroxyl groups at both ends. Those having are also preferable as the component of the segment (B).
Similarly, an oligomer obtained by addition-reacting ethylene oxide or propylene oxide to a terminal hydroxyl group of polycarbonate or polyorganosiloxane, and particularly an oligomer having a molecular weight of about 2000 or less is also preferable as the chain diol.

Similarly, it has 3 carbon atoms such as propiolactone, butyrolactone, valerolactone, and caprolactone.
The above lactones and hydroxyalkylcarboxylic acids having 4 or more carbon atoms such as hydroxypropylcarboxylic acid and hydroxybutylcarboxylic acid are also useful as the component of the amorphous segment (B). That is, the segment (B) can be formed by using an amorphous copolymer containing them or by amorphizing by using two or more kinds of crystalline homopolymers by mixing. For example, 10 to 90 mol% of polycaprolactone, especially about 20 to 80% of other lactams (eg glycolide, lactide, etc.)
Amorphous polymers can be obtained by random copolymerization or block copolymerization of short segments (for example, a molecular weight of 2000 or less, particularly 1000 or less).
Similarly, for example, polycaprolactone and polyethylene adipate may be mixed and used at a weight ratio of about 1/2 to 2/1 to make them amorphous to form the segment (B).

The term "main component" as used herein means one that occupies 50% by weight or more of the whole. That is, 50 of segment (B)
% Or more is derived from an aliphatic dicarboxylic acid, a chain diol, a lactone having a carbon number of 3 or more, and / or a hydroxyalkylcarboxylic acid having a carbon number of 4 or more, but other components such as an aromatic nucleus or a cyclic structure. A dicarboxylic acid having an carboxylic acid, an aromatic diol, an aromatic hydroxycarboxylic acid, and / or a hydroxycarboxylic acid having 3 or less carbon atoms, such as a component derived from lactic acid or glycolic acid.
The content may be 0% or less. The purpose of adding these auxiliary components is hydrophilicity, water repellency, dyeability, flexibility, elastic recovery, stability, antioxidant property, stability, heat resistance, gas barrier property, degradability, smoothness, release property. Improvements in moldability, fluidity, moldability, compatibility with plasticizers, etc., and cost reduction.

The segment (B) is a soft segment, which is an important element for realizing the excellent flexibility, toughness, elastic recovery property and excellent compatibility with the plasticizer of the copolymer of the present invention. In particular, by making the segment (B) amorphous (non-crystalline), the flexibility, toughness, and elastic recovery can be further improved, and the affinity with a plasticizer and molding It has been found that the transparency of the product is also improved. From the viewpoints of flexibility, toughness, and elastic recovery, the glass transition point of the segment (B) is preferably low, particularly preferably 20 ° C. or lower, and 0 ° C.
It is most preferred that: Whether the polymer or oligomer is crystalline is examined by a scanning differential calorimeter (hereinafter referred to as DSC) after it is made into a fiber or film, sufficiently stretched and / or heat-treated, and an endothermic peak of melting of the crystal is present. Whether or not to do so, or easily by an X-ray diffraction test of a stretch-oriented fiber or film. The glass transition point can also be easily measured by the DSC method.

Homopolymers of polyesters containing the above-mentioned aliphatic dicarboxylic acid and linear diol as components are often crystalline. Examples of these melting points are polyethylene adipate 44 ° C, polyethylene suberate 64 ° C,
Polyethylene azelate 50 ° C., polyethylene sebacate 72 ° C., polyethylene decamylate 85 ° C., polybutylene succinate 116 ° C., polybutylene adipate 69 ° C., polybutylene sebacate 65 ° C., polyhexamethylene sebacate 75 ° C., etc. . However, by randomly copolymerizing two or more kinds of diols and / or dicarboxylic acids as components, the polymer can easily be made amorphous and the melting point (endothermic peak) can be eliminated.

For example, in the case of two-component random copolymerization, the copolymerization ratio (molar ratio) is 5/95 to 95/5, especially 6/94.
In the range of up to 94/6, it often becomes amorphous and 10
In the range of / 90 to 90/10, an amorphous polymer is obtained in most cases. The same applies when random copolymerization is carried out using a plurality of types of lactone or hydroxycarboxylic acid, and when three or more types of components are used, it can be more easily made amorphous. Therefore, an infinite number of amorphous polymers can be obtained by using plural kinds of aliphatic dicarboxylic acids, chain diols, hydroxycarboxylic acids, lactones and the like, and changing the combination and the copolymerization ratio. The glass transition point of the aliphatic polyester composed of the aliphatic dicarboxylic acid, chain diol, and lactone is 0 ° C. or lower in most cases.

Similarly, as a component of the segment (B),
For example, the segment (B) in the composition can be made amorphous even when a plurality of (crystalline) homopolymers of a polyester containing an aliphatic dicarboxylic acid and a linear diol as a component are mixed and mixed. For example, polyethylene adipate and polybutylene sebacate are crystalline by themselves, but a 1/1 mixture of the two is used as the component for the segment (B), and the terminal hydroxyl group is used as an initiator with L as the initiator while being sufficiently stirred. -By melt-polymerizing lactide (or D-lactide), poly L (or D) -lactic acid homopolymer is used as a segment (A), and (by mixing) amorphized polyethylene adipate and polybutylene sebacate are respectively segmented. A composition obtained by mixing two kinds of block copolymers (B) is obtained, which is an example of a preferred embodiment of the present invention. Amorphization due to mixing varies depending on the combination of materials, but the mixing ratio (weight ratio) is 1/3 to 3
In many cases, it becomes amorphous when mixed in a ratio of / 1, particularly in the range of 1/2 to 2/1. The same applies to polymers derived from hydroxycarboxylic acids and lactones, which can be more easily made amorphous by mixing three or more kinds.

The combination form of the segments (A) and (B) is not particularly limited. For example, AB type in which one (A) and one (B) are bound, BAB type in which two (B) are bound to one (A), the opposite ABA type, a plurality of ( It is arbitrary such as ABABA type in which A) and a plurality of (B) are combined. However, from the viewpoint of ease of production and excellent physical properties (crystallinity and heat resistance), simple ones such as AB type, ABA type and BAB type are often preferable.

As the bond between the segments (A) and (B), an ester bond is most often used, but other chemical bonds may be bonded as a "joint". For example, a polymer for the segment (A) and a polymer for the segment (B), both of which have a hydroxyl group at the terminal, can be reacted with a dicarboxylic acid anhydride or a dicarboxylic acid chloride to bond them. Similarly, a diisocyanate compound can be reacted to bond both. That is,
Well-known chemical bonds such as ester bond, urethane bond, urea bond, amide bond, carbonate bond and the like can be applied as the "joint".

The molecular weights of the segments (A) and (B) are not particularly limited. The molecular weights of the segments (A) and (B) may be selected depending on the weight ratio and the desired physical properties. However, in general, those having a too small molecular weight are not preferable because the features of the block (segment) copolymer are not clear. The molecular weight of the segment is preferably 2000 or more, more preferably 5000 or more, and in many cases 1000
0-300000, especially 20000-200000 is widely used.

If the weight ratio of the segments (A) and (B) is too small, the effect will be poor. Therefore,
The weight ratio A / B is preferably in the range of 20/80 to 95/5, particularly preferably in the range of 30/70 to 90/10, and most preferably in the range of 40/60 to 86/14. The segment (A) is a hard segment, and the more it is, the better the crystallinity and heat resistance are. On the other hand, the segment (B) is a soft segment, and the more it is, the more flexibility, impact resistance, elastic recovery rate, affinity with additives, etc.
Excellent in degradability. Therefore, the ratio of segment (A) / (B) can be selected according to the purpose of use and can be applied to a wide range of applications.

The molecular weight of the copolymer of the present invention is not particularly limited, but in many cases, it is preferably 50,000 or more, and 8
0000 or more is particularly preferable, and 100,000 to 3000
The range of 00 is most widely used. As a few examples of preferable molecular structures, poly L-lactic acid (homopolymer) having a molecular weight of 150,000 is used as a segment (A) and a molecular weight of 5 is obtained.
The segment (B) is a random copolymer of 0000 polyethylene / hexane adipate in a molar ratio of 1/1.
B type block copolymer (molecular weight 200,000), BAB type (molecular weight 250,000), ABA type (molecular weight 240,000) composed of a segment (A) having a similar molecular weight of 80,000 and a segment (B) having a molecular weight of 80,000. .

The copolymer composition of the present invention does not have to have the same molecular structure of all molecules (the structure of block copolymers need not be the same, and an aggregate of various molecular structures such as a mixture of AB type and ABA type). Good, of course, segment (A)
The chemical composition is limited to one type to maintain crystallinity,
The segment (B) is also useful as a mixture of a plurality of chemical compositions as described above. In addition, even if the chemical composition is constant, a mixture of compounds having different molecular weights is widely used. In the actual polymerization process, aggregates of various molecular weights (for example, Gaussian distribution) are obtained due to statistical variations. However, it is practically sufficient if the components and molecular weights of the blocks (segments) are represented by average values.

As described above, the segment (B) which constitutes the block copolymer of the present invention is, within the range of 50% by weight or less, "an aliphatic dicarboxylic acid, a chain diol, a lactone having 3 or more carbon atoms, And polyester raw materials (constituent components) other than "hydroxycarboxylic acid having 4 or more carbon atoms" can be copolymerized. Examples of copolymerizable components or raw materials include (1) glycolic acid, lactic acid, hydroxybutyric acid,
Hydroxycarboxylic acid such as hydroxybenzoic acid,
(2) Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, 5-sulfoisophthalic acid (particularly alkali metal salt), and naphthalenedicarboxylic acid, (3) cyclohexanedimethanol, hydroquinone, bispheno, and the like, to which ethylene oxide is added. Alicyclic diols and aromatic diols, and dimer lactones such as (4) glycolide and lactide. Similarly, polymers such as polyalkylene ether, polyalkylene carbonate, and polyorganosiloxane are also copolymerizable and useful if they are used with care so as to maintain the amorphous property of the segment (B).

The block copolymer composition of the present invention is characterized in that since the segment (A) is crystalline, the heat resistance of the entire polymer is superior to that of an amorphous polymer. The degree of crystallinity can be evaluated by DSC analysis or melting point as described above. The larger the endothermic amount in DSC analysis, the higher the crystallinity. For the purposes of the present invention, the melting endotherm of the composition is preferably 5 joules (J) / g or more, particularly preferably 10 J / g or more, most preferably 20 J / g or more. The poly L-lactic acid homopolymer has a melting endotherm of about 40 to 50 J / g and a melting point of 170 to 180 ° C.
It is about. From the viewpoint of heat resistance, the melting point of the copolymer of the present invention is preferably 130 ° C or higher, particularly preferably 140 ° C or higher, and most preferably 150 ° C or higher.

In general, polylactic acid includes direct polymerization of lactic acid (dehydration condensation), condensation of lactic acid ester (methyl ester, ethyl ester, etc.) (dealcoholization), and cyclic lactic acid 2
It is polymerized by ring-opening polymerization of lactide which is a monomer. The copolymer composition of the present invention can be easily obtained by forming the segment (A) by ring-opening polymerization of lactide. In the direct polymerization (dehydration condensation) of lactic acid or the condensation method of lactic acid ester, random copolymerization easily occurs, and block copolymerization is often difficult. Lactide includes L-lactic acid dimer LL-lactide (referred to as L-lactide), D-lactic acid dimer DD-lactide (referred to as D-lactide), L-lactic acid and D-lactic acid. L / containing
There are three types of D-lactide (also called mezolactide). L-lactide or D-lactide is preferably used for the polymerization of the crystalline segment (A).

The block copolymer composition of the present invention firstly prepares (1) a polymer which forms the amorphous segment (B), while (2) L-lactide or D-
It can be easily obtained by a two-step method in which lactide is reacted and polymerized to form the crystalline segment (A). For this purpose, one or both of the molecular ends of the segment (B) -forming polymer produced in the first step must be a hydroxyl group. In this method, the segment (B)
If one of the molecular ends of the forming polymer is a hydroxyl group, AB
Type block copolymer is obtained, and if both ends are hydroxyl groups, an ABA type block copolymer is obtained.

The degree of polymerization (molecular weight) and the terminal group of the polyester can be easily controlled by changing the molar ratio of the carboxyl group and the hydroxyl group of the polymerization raw material. For example, if the raw materials dicambonic acid and the diol are equimolar, the end groups are also equimolar. If the number of hydroxyl groups in the raw material is 1 mol% more than the carboxyl groups, a polymer having a degree of polymerization of about 100 and hydroxyl groups at both ends is obtained. can get. Similarly, when 1 mol% of monoalcohol is added to the raw material, a polyester having a degree of polymerization of about 100 and a hydroxyl group at one end and a blocked end at the other end can be obtained. Similarly, also in the polymerization of lactide, the degree of polymerization of polylactic acid and the terminal group can be controlled by adding a small amount of diol, monool, dicarboxylic acid or monocarboxylic acid to the raw material.

As another method for producing the block copolymer of the present invention, first, (1) a polymer for a crystalline segment (A) having a hydroxyl group or a carboxyl group at one or both molecular terminals and an amorphous segment There is a method in which both polymers for (B) are prepared, and then (2) a polyfunctional compound is reacted with them to bond (A) and (B). Compounds such as dicarboxylic acid anhydrides, dicarboxylic acid halides, dicarboxylic acids, polyvalent carboxylic acids, and diisocyanates can be used to react with hydroxyl groups, and diamines, polyvalent amines, diols, and polyhydric alcohols can be used to react with carboxyl groups. and so on. In this method, AB type, ABA type, B type
In addition to AB type, ABAB, ABABA, BABAB and other various types, and by applying a trifunctional compound, a branched structure and the like can be obtained, and a mixture of various types can be easily produced. . The block copolymer of the present invention contains stabilizers, antioxidants, ultraviolet absorbers, pigments, colorants, various inorganic particles, various fillers, organic and inorganic crystal nuclei as secondary additives depending on the purpose of use. Agent, water repellent, hydrophilic agent, release agent, plasticizer, bioactive agent, antibacterial agent,
Preservatives and the like can be added.

In the following examples,% and parts are weight ratios unless otherwise specified. The molecular weight of the aliphatic polyester was determined by GPC analysis of a 0.1% chloroform solution of the sample.
It is a weight average value of dispersion of polymer components excluding components having a molecular weight of 1000 or less. The DSC test was carried out at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere in a sample of 10 mg. The impact strength of the sample polymer was 6.35 m in width using an injection molding machine.
The test piece with a notch of m was prepared, and ASTM D-25
6 Measured according to the Izod impact test method.

[0027]

【Example】

Example 1 Random copolymer of polyethylene adipate and polyhexane adipate in a molar ratio of 1/1 (amorphous)
With a molecular weight of 43000, one end having a hydroxyl group of 50 parts, L-lactide having an optical purity of 99.5% or more of 250 parts, a polymerization catalyst tin octylate 100 ppm with respect to lactide, and an antioxidant Ciba Geigy Irganox 1010 with respect to the whole. 0.1% was continuously supplied to a twin-screw kneading extruder having a diameter of 30 mm, and 190% while stirring at 30 rpm under a nitrogen stream.
Polymerization was performed at an average temperature of 12 minutes for 12 minutes, the mixture was extruded from a nozzle, cooled with water to form a strand, and then cut to obtain a chip C1. The chip C1 was dehydrated and dried, and then treated at 140 ° C. in nitrogen for 4 hours (solid phase polymerization) to obtain a block copolymer BP1. The molecular weight of the copolymer BP1 was 203,000.

Almost the same as block copolymer BP1, except that 50 parts of a 1/1 mixture of polyethylene adipate having a molecular weight of 45,000 and polyhexane adipate having a molecular weight of 44000 was used instead of the polyethylene / hexane adipate random copolymer. , And L-lactide were reacted therewith to obtain a block copolymer BP2. The molecular weight of the copolymer BP2 was 205,000.

For comparison, polylactic acid homopolymer HP1 was obtained in substantially the same manner as copolymer BP1, but using only L-lactide, tin octylate and Irganox. The molecular weight of the homopolymer HP1 was 217,000. Similarly, for comparison, a molecular weight of 440 was used as a copolymerization component.
The block copolymer obtained by using 50 parts of polyhexane adipate of 00 is designated as BP3. The molecular weight of the copolymer BP3 was 204,000.

The above block copolymers BP1, BP2, B
Table 1 shows melting points, melting endotherms, and impact strengths of P3 and homopolymer. As shown in Table 1, it is clear that the block copolymer of the present invention has sufficient heat resistance and excellent impact resistance. The test piece for the impact test of the block copolymer BP3 of Comparative Example was slightly clouded, and the transparency was slightly inferior to that of the homopolymer HP1. On the other hand, although the test pieces of the block copolymers BP1 and BP2 of the present invention were slightly cloudy, the transparency was higher than that of BP3 and was close to that of a homopolymer.

Example 2 Polycaprolactone having hydroxyl groups at both ends and having a molecular weight of 33,000, which was polymerized using hexanediol as a polymerization initiator, was used as a prepolymer PP1. Similarly, a poly L-lactic acid homopolymer having a molecular weight of 96000, which is polymerized using hexanediol as a polymerization initiator, is referred to as prepolymer PP2. Similarly, 0.5 mol% of hexanediol
Prepolymer PP3 was prepared by using polyhexane adipate having a molecular weight of 39000 and hydroxyl groups at both ends, which was obtained by polymerization in excess.
And 14 parts each of prepolymers PP1 and PP3,
72 parts of PP2 and 0.2 parts of terephthalic acid dichloride were continuously fed to the twin-screw kneading extruder of Example 1 and reacted at 190 ° C. for an average of 6 minutes, then extruded from a nozzle, cooled and cut into chips to 120 ° C. After treatment for 2 hours in nitrogen, washed with acetone containing 0.3% of water and dried to obtain a block copolymer BP4. The copolymer BP4 has a molecular weight of 196000,
Both ends are hydroxyl groups and are presumed to be a mixture of AB type, ABA type, BAB type and the like. The melting point of the copolymer BP4 is 161.
℃, melting endotherm 27J / g, impact strength 4.7kg · cm
/ Cm.

[0032]

[Table 1]

[0033]

EFFECTS OF THE INVENTION According to the present invention, the drawback of polylactic acid homopolymer, which is hard and brittle, is effectively improved while suppressing the deterioration of heat resistance and crystallinity, and a novel decomposition which has heat resistance, flexibility and toughness. Polymers have become available. The block copolymer of the present invention has excellent crystallinity and heat resistance as compared with a random copolymer, and further has two phases of a hard segment and a soft segment, thereby providing flexibility, toughness,
It is possible to obtain a material having excellent elastic recovery. Further, the copolymer of the present invention tends to have a faster decomposition rate than a homopolymer, and is suitable for applications where the homopolymer has a too slow decomposition rate. Similarly, the copolymer of the present invention is more easily dissolved in a solvent than a homopolymer, and is easy to produce a film by a solvent method or to coat a cloth or the like. Further, the copolymer of the present invention is characterized in that its properties can be changed in a very wide range by changing the composition, molecular weight, and weight ratio of each segment, and the range of application is extremely wide.

The copolymer of the present invention is a fiber, knit, woven fabric, non-woven fabric, paper, net, rope, cord, sheet, film, plate, rod,
It can be used for tubes, containers, bags, plates, tableware, various parts, and other various molded products.

Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number for FI Technical location C08J 5/00 CFJ C08J 5/00 CFJ D01F 6/84 303 D01F 6/84 303Z D02G 3/02 D02G 3/02 (72) Inventor Yoshikazu Kondo 2-5-31, Kuniyoshi, Hofu City, Yamaguchi Prefecture (72) Inventor, Taiji Kanda, Hofu City, Yamaguchi Prefecture 3818-2

Claims (5)

[Claims] 1. A crystalline segment (A) comprising a substantially homopolymer of poly L-lactic acid or poly D-lactic acid,
Amorphous segment containing at least two compounds selected from the group of "aliphatic dicarboxylic acid, chain diol, lactone having 3 or more carbon atoms, and hydroxyalkylcarboxylic acid having 4 or more carbon atoms" as a main component A polylactic acid block copolymer composition in which (B) is bonded. 2. The copolymer composition according to claim 1, wherein the crystal has a melting endotherm of 5 joules or more per 1 g of the polymer as measured by a scanning differential calorimeter in a sufficiently crystallized and / or oriented state. Stuff. 3. An “aliphatic dicarboxylic acid, a chain diol,
Main component is at least two kinds of compounds selected from the group consisting of lactone having 3 or more carbon atoms and hydroxyalkylcarboxylic acid having 4 or more carbon atoms, and having a hydroxyl group at at least one of the molecular ends and is amorphous. Oligomers of /
The method for producing a block copolymer composition according to claim 1, wherein L-lactide or D-lactide is reacted with the polymer in the molten state in the presence of a polymerization catalyst. 4. An “aliphatic dicarboxylic acid, a chain diol,
At least two compounds selected from the group consisting of "lactones having 3 or more carbon atoms and hydroxyalkylcarboxylic acids having 4 or more carbon atoms" as main components, and at least two types having a hydroxyl group at at least one of the molecular terminals. The block copolymer composition according to claim 1, wherein L-lactide or D-lactide is reacted with a mixture of oligomers and / or polymers in a molten state in the presence of a polymerization catalyst. Production method. 5. A fiber, a knitted fabric, a woven fabric, a non-woven fabric, which comprises at least a part of the copolymer composition according to claim 1 or 2.
Paper, felt, cord, rope, sheet, film, bar,
Tubes, plates, plates, dishes, containers, various parts and other molded products.