JPH093150A - Production of block polyester - Google Patents

Abstract

PURPOSE: To obtain a block polyester which though biodegradable and having a high m.p. as an aliph. polyester, is thermally stable and has a good moldability, high mechanical strengths, and well balanced physical properties. CONSTITUTION: A block polyester having a number average mol.wt. of 30,000 or higher is produced by melt mixing 1-99wt.% aliph. polyester having an m.p. of 70 deg.C or higher, a number average mol.wt. of 10,000 or higher, and substantially hydroxylated molecular ends with 99-1wt.% polylactic acid having a number average mol.wt. of 10,000 or higher in the presence of a phosphorus compd. and reacting the resultant product with a polyisocyanate compd. in an amt. of 0.1-5wt.% of the sum of the aliph. polyester and the polylactic acid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a biodegradable block polyester.

[0002]

2. Description of the Related Art At present, it is no exaggeration to say that resins that exhibit biodegradability are, apart from natural products, only aliphatic polyesters, which are roughly classified into (i) ring-opening polyaddition.
(Ii) It is classified into a type synthesized by a polycondensation reaction. A typical polyester obtained by the ring-opening polyaddition of (i) is polylactic acid. This polylactic acid has a number average molecular weight of 100,000 or more, a melting point of 187 ° C., good transparency, and is a seemingly amorphous hard polyester. However, since this polylactic acid tends to be brittle and has poor thermal stability, it is also known that when it is held at a temperature of the melting point or higher for a few minutes to a few tens of minutes, the molecular weight remarkably decreases.
For example, it is also known that the polylactic acid having a number average molecular weight of about 200,000 is held at 200 ° C. for 20 minutes to give a molecular weight of about 70,000. This, of course in terms of physical properties, has a significant adverse effect on moldability.

On the other hand, a typical polyester obtained by the polycondensation reaction (ii) was developed by Showa Highpolymer Co., Ltd., and has a melting point of 70 ° C. or higher, which is currently commercially available, and has 1 to 2 molecules in the molecule. An aliphatic polyester (brand name, Bionore) containing individual urethane bonds is known. This aliphatic polyester has good thermal stability, for example, 3 at 200 ° C.
Even if kept for 0 minutes, almost no decrease in molecular weight was observed,
It has the feature that moldability is not impaired. However, this aliphatic polyester has a melting point of 120 ° C. or lower, and since the aliphatic polyester is crystalline, it is in the form of a white wax, which is a property that should be called semi-rigid. That is, the melting point of this aliphatic polyester is not necessarily as high as that of polyethylene, and the molded product tends to lack transparency.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, has a high melting point as an aliphatic polyester, and has thermal stability and good moldability, and has a good balance of physical properties. It is an object of the present invention to provide a method for producing a good biodegradable block polyester.

[0005]

Means for Solving the Problems As a result of various studies, the inventors of the present invention have been able to complement each of the defects of both polyesters by using a specific aliphatic polyester and polylactic acid in combination. Further, they have found that the above object can be achieved by adding and reacting an appropriate amount of a polyvalent isocyanate compound thereto, and have completed the present invention. That is, the present invention provides [I] (1) 1 to 99% by weight of an aliphatic polyester having a melting point of 70 ° C. or higher, a number average molecular weight of 10,000 or higher, and a terminal group substantially a hydroxyl group, and (2) 99 to 1% by weight of polylactic acid having a number average molecular weight of 10,000 or more is melt-mixed in the presence of (3) a phosphorus compound, and then the total of the aliphatic polyester of (1) and the polylactic acid of (2) is added. A method for producing a block polyester, which comprises adding 0.1 to 5 parts by weight of [II] a polyvalent isocyanate compound to 100 parts by weight to make the number average molecular weight of 30,000 or more. Is provided.

In the present invention, the amount of the phosphorus compound (3) used is 0.001 to 3 parts by weight based on 100 parts by weight of the total amount of the aliphatic polyester (1) and the polylactic acid (2). There is provided a method for producing the block polyester.

Further, the present invention provides that the phosphorus compound (3) is
Is at least one inorganic or organic phosphorus compound selected from the group consisting of phosphoric acid and its alkyl esters, phosphonic acid organic esters, phosphorous acid, organic esters of phosphorous acid and polyphosphoric acid; A method for producing a block polyester is provided.

Further, the present invention relates to [I] (1) 1 to 99% by weight of an aliphatic polyester having a melting point of 70 ° C. or higher, a number average molecular weight of 10,000 or higher, and a terminal group substantially a hydroxyl group. (2) Number average molecular weight is 10,000
0 to 100% by weight of polylactic acid consisting of
When 100 parts by weight of the total amount of the aliphatic polyester of (2) and polylactic acid of (2) are added and reacted with 0.1 to 5 parts by weight of the polyvalent isocyanate compound, the reaction of (1) in the molten state is performed. After a polyvalent isocyanate compound is added and reacted with the aliphatic polyester, the polylactic acid of (2) is added and melt-reacted to give a number average molecular weight of 30,000 or more. A manufacturing method is provided.

Hereinafter, the present invention will be described in more detail. The aliphatic polyester referred to in the present invention means an aliphatic (including cycloaliphatic) glycol (hereinafter, abbreviated as glycols) and an aliphatic (including cycloaliphatic) dicarboxylic acid or an acid anhydride thereof (hereinafter, fat). (Abbreviated as group dicarboxylic acid)
And a tri- or tetra-functional polyhydric alcohol, oxycarboxylic acid and polycarboxylic acid (or acid anhydride thereof) as a third component, if necessary.
Obtained by reacting at least one polyfunctional component selected from the following: melting point of 70 ° C. or higher, number average molecular weight of 10,
It is an aliphatic polyester having a terminal group of substantially 000 or more and a hydroxyl group.

As the glycols used, for example, ethylene glycol, 1,4-butanediol, 1,6
-Hexanediol, 1,8-octanediol, 1,
Mention may be made of 10-decanediol, 1,4-cyclohexanediol, as well as mixtures thereof.

Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid, 1,10
-Decanedicarboxylic acid, succinic anhydride, 1,4-cyclohexanedicarboxylic acid, and mixtures thereof.

In addition to these glycols and aliphatic dicarboxylic acids, if necessary, as a third component,
At least one polyfunctional component selected from trifunctional or tetrafunctional polyhydric alcohols, oxycarboxylic acids and polycarboxylic acids (or acid anhydrides thereof) may be added and reacted. By adding this third component, long-chain branching occurs in the molecule, the molecular weight becomes large and Mw / Mn becomes large, that is, the molecular weight distribution becomes wide, which is a desirable property for forming a film or sheet. Can be given. The amount of the third component added is such that the total amount of the components of the aliphatic dicarboxylic acid is 10 in order to avoid the risk of gelation.
It is 0.1 to 5 mol% in the case of trifunctional with respect to 0 mol%, and 0.1 to 3 mol% in the case of tetrafunctional. Examples of the trifunctional or tetrafunctional third component include polyhydric alcohols such as trimethylolpropane, glycerin and pentaerythritol, malic acid, citric acid and oxycarboxylic acids such as tartaric acid, trimellitic anhydride and pyromellitic anhydride. Examples thereof include polycarboxylic acids (or acid anhydrides thereof) such as acids, benzophenonetetracarboxylic acid anhydrides, cyclopentanetetracarboxylic acid anhydrides.

An aliphatic polyester is synthesized by the usual esterification reaction and deglycolization reaction using the above components. Examples of the deglycolization reaction catalyst include titanium compounds such as acetoacetoyl type titanium chelate compounds and organic alkoxy titanium compounds.
Examples of these include, for example, diacetoacetoxyoxytitanium ("Narsem titanium" manufactured by Nippon Kagaku Sangyo Co., Ltd.),
Examples thereof include tetraethoxy titanium, tetrapropoxy titanium, and tetrabutoxy titanium. The titanium compound is used in an amount of 0.001 to 1 part by weight, preferably 0.01 to 0.
1 part by weight. The titanium compound may be added from the beginning of esterification or immediately before the deglycolization reaction.

The esterification reaction is carried out at 160 to 230 ° C. for 5
It can be carried out for up to 16 hours, preferably under an inert gas atmosphere. When the temperature is lower than this temperature, the reaction rate is slow and the practicality is poor. If the temperature is higher than this temperature, the risk of decomposition increases and it is better to avoid it. Therefore, it is preferred to carry out the first stage esterification reaction at a temperature between 180 and 220 ° C. In the esterification reaction, the aliphatic polyester has an acid value of 30 or less, preferably 15 or less, and more preferably 10 or less.
It will be implemented until the following is reached. In this case, the higher the molecular weight, the smoother the increase in the molecular weight due to the deglycolization reaction. The deglycolization reaction is 2 to 16 at 170 to 230 ° C. under a reduced pressure of 5 Torr or less.
Will be carried out for hours. More preferably, it is carried out at 180 to 220 ° C. under a high vacuum of 1 Torr or less from the viewpoint of reaction rate and prevention of decomposition. The resulting aliphatic polyester has a substantially hydroxyl group at the terminal group and has an acid value of zero.

The aliphatic polyester thus obtained must be biodegradable and has a melting point of 70 ° C.
As described above, it is necessary that the number average molecular weight is 10,000 or more and the terminal group is substantially a hydroxyl group. If the melting point of the aliphatic polyester is less than 70 ° C, the heat resistance is insufficient, and if the number average molecular weight is less than 10,000, the amount of polyvalent isocyanate compound used to obtain the required physical properties and moldability increases. As a result, the risk of gelation is significantly increased.

As the aliphatic polyester used in the present invention, a commercially available product may be used as long as it satisfies the above-mentioned specific conditions. For example, "Bionore" manufactured by Showa High Polymer Co., Ltd. may be mentioned. To be In the present invention, the aliphatic polyester used particularly preferably is 1,4-
In this type, at least one glycol selected from butanediol, ethylene glycol and 1,4-cyclohexanedimethanol is reacted with succinic acid with or without other glycols. In this case, a part of succinic acid is produced, and adipic acid, sebacic acid,
A type in which a long-chain dibasic acid such as dodecanedioic acid is substituted may be used.

The polylactic acid used in the present invention is not particularly limited in its synthetic method and physical properties, but from a practical point of view, a cyclic dimer of L-lactic acid is purified and synthesized by ring-opening polyaddition. Number average molecular weight of 10,000 or more,
Desirably, the melting point is 50,000 or more and the melting point is 170 ° C. or more. The reason for this is that the apparent melting point of the block polyester is determined by the high melting point component, although it depends on the blending ratio of the aliphatic polyester and the polylactic acid. When the number average molecular weight of polylactic acid is less than 10,000, it is difficult to mold and it is brittle and cannot be put to practical use.

(1) an aliphatic polyester having a melting point of 70 ° C. or higher, a number average molecular weight of 10,000 or more, and a terminal group substantially a hydroxyl group, and (2) a number average molecular weight of 1
The compounding ratio with the polylactic acid of 10,000 or more is 1 to 99% by weight of aliphatic polyester and 99 to 1% by weight of polylactic acid, preferably 10 to 90% by weight of aliphatic polyester and 90 to 10% by weight of polylactic acid. Consists of. When the blending ratio of the aliphatic polyester is less than 1% by weight or the blending ratio of the polylactic acid is more than 99% by weight, the thermal stability is poor, and a block polyester having satisfactory moldability and mechanical properties cannot be obtained. When the compounding ratio of the aliphatic polyester is more than 99% by weight or the compounding ratio of the polylactic acid is 1
If it is less than wt%, the blocking effect does not appear.

The first method of the present invention comprises 1 to 99% by weight of the aliphatic polyester (1) and polylactic acid 99 to 1 (2).
Wt% and (3) are melt mixed in the presence of a phosphorus compound,
Next, 0.1 to 5 parts by weight of a polyvalent isocyanate compound is added to 100 parts by weight of the aliphatic polyester of (1) and the polylactic acid of (2) to cause a reaction so that the number average molecular weight is 30, 000 or more block polyester.

When the aliphatic polyester of (1) and the polylactic acid of (2) are melt-mixed, the phosphorus compound is used in combination so that the action of the catalyst used in esterification and ring-opening polyaddition is stopped. Especially. If the activity of the catalyst is not diminished, transesterification occurs when the aliphatic polyester and polylactic acid are melt-mixed, resulting in defects such as a marked change in melting point and physical properties.

The phosphorus compounds used for this purpose include the following types of inorganic or organic phosphorus compounds. (A) Phosphoric acid and its alkyl esters Commercially available products include trialkyl esters such as trimethyl phosphate, triethyl phosphate, and tributyl phosphate. (B) Phosphonic acid organic ester Examples of commercially available products include dibutyl butyl phosphonate. (C) Phosphorous acid Alone or in combination with other phosphorus compounds, the strongest hue stabilizing effect and oxidative decomposition preventing function are recognized. (D) Organic esters of phosphorous acid For example, dibutyl hydrogen phosphite is commercially available and can be used in the present invention. Triphenyl phosphite is also effective if added in an amount, and is useful when 0.1 to 0.5% is added, but it also tends to deteriorate the properties of polyester. (E) Other inorganic phosphorus compounds For example, polyphosphoric acid.

The amount of the phosphorus compound used varies depending on the molecular weight of the phosphorus compound (content of phosphorus atoms), but in general, the total amount of the aliphatic polyester (1) and the polylactic acid (2) is 100 parts by weight. It is 0.001 to 3 parts by weight, preferably 0.01 to 1 part by weight. If the amount of the phosphorus compound is less than 0.001 part by weight, the effect of addition is not recognized, and if it is more than 3 parts by weight, the effect does not increase.

Further, in the present invention, a desired amount of the polyvalent isocyanate compound is added and reacted with a mixture of the aliphatic polyester (1) and the polylactic acid (2) melt-mixed in the presence of a phosphorus compound. The number average molecular weight of the obtained block polyester is 30,000 or more.

Examples of the polyvalent isocyanate compound used include 2,4-tolylene diisocyanate, 2,
Mixture of 6-tolylene diisocyanate and 2,4-tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, diphenyl methane diisocyanate, hydrogenated xylylene diisocyanate , Hydrogenated diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, and an adduct of diisocyanate with a polyhydric alcohol, and further, a trimer of diisocyanate. . Among them, aliphatic and cyclic aliphatic diisocyanates such as hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate and isophorone diisocyanate can be mentioned.

The amount of polyvalent isocyanate compound used is
The amount is 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the total amount of the aliphatic polyester (1) and the polylactic acid (2). If the amount of the polyvalent isocyanate compound used is less than 0.1 part by weight, the effect of addition is poor, and 5
When used in excess of parts by weight, the risk of gelation increases.

In the second method of the present invention, 1-99% by weight of the aliphatic polyester (1) and polylactic acid 99-1 of (2) are used.
In a molten state, when 0.1 to 5 parts by weight of the polyvalent isocyanate compound is added to 100 parts by weight of the aliphatic polyester of (1) and the polylactic acid of (2) and reacted, After the polyvalent isocyanate compound is added to and reacted with the aliphatic polyester of (1) in (2),
Of polylactic acid is added and melt-reacted to obtain a block polyester having a number average molecular weight of 30,000 or more.

In this method, the melted state (1)
After the polyvalent isocyanate compound is added and reacted with the aliphatic polyester of (2), the polylactic acid of (2) is added and the melt reaction is performed because the organotin compound is used as a catalyst during the synthesis of the polylactic acid of (2). When (2) is used, the polylactic acid of (2) and the aliphatic polyester of (1) are melt-mixed at the same time without using a phosphorus compound, and a polyvalent isocyanate compound is added thereto, whereby the above-mentioned transesterification is carried out. Besides, (2)
The reason is that the polylactic acid portion of (4) may react with the polyvalent isocyanate compound rapidly and gelation may occur, which is to prevent this.

The amount of the polyvalent isocyanate compound added is
It is 0.1 to 5 parts by weight based on 100 parts by weight of the total of the aliphatic polyester (1) and the polylactic acid (2). In this method, when the polyvalent isocyanate compound is added to the melted (1) aliphatic polyester in advance, the polyvalent isocyanate compound within the above range, that is, within the range of 0.1 to 5 parts by weight is used. A block polyester having a constant structure and stable physical properties can be obtained by adding all of the components at once and reacting for a required time, then adding polylactic acid, uniformly melting and mixing, and reacting. Although the reason is not always clear, the thermal decomposability of polylactic acid is greatly improved by blocking, so that it does not hinder the actual molding operation. The required time mentioned above is the time during which the mixture is uniform and when molded, the molded product, for example, the film has no unevenness or precipitates, and is usually about 15 to 60 minutes.

The block polyester of the present invention obtained as described above may have different components depending on the mixing ratio of polylactic acid and aliphatic polyester, but from the viewpoint, the following three types of polyesters are mixed. Can be regarded as the body. That is, (a) block polyester of polylactic acid and aliphatic polyester. (B) Increase in molecular weight due to isocyanate of aliphatic polyesters. (C) Polylactic acid comrades linked by isocyanate. Actually, it is assumed that the block polymer of polylactic acid and aliphatic polyester in (a) also plays the role of the compatibilizing agent in (a) and (c). In the present invention, the above is collectively referred to as block polyester.

The block polyester obtained in the present invention has a number average molecular weight of 3 in order to maintain moldability and physical properties.
It is necessary to be 50,000 or more.

The block polyester according to the present invention is used for its practical application, including inorganic and organic fillers, reinforcing materials, and
Needless to say, release agents, waxes, various stabilizers, colorants and the like can be used in combination as required.

[0032]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.
The melting point was measured by the DSC (differential scanning calorimeter) method. The molecular weight was measured by the following GPC measurement. Shodex GPC SYSTEM-11 (manufactured by Showa Denko KK) Eluent CF ₃ COONa 5 mM / HFIP (hexafluoroisopropanol) sample column HFIP-800P HFIP-80M × 2 reference column HFIP-800R × 2 polymer solution 0.1 wt%, 200 μl Column temperature 40 ° C Flow rate 1.0 ml / min Pressure 30 kg / cm ² Detector Shodex RI Molecular weight standard PMMA (Shodex STANDA)
RD M-75)

Example 1 Aliphatic Polyester (A) Synthesis In a 1 liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube, 284 g of 1,4-butanediol and 348 g of succinic acid were added. After charging, esterification at 210 to 215 ° C. in a nitrogen gas stream to give an acid value of 9.1, 0.1 g of tetraisopropoxy titanium was added as a deglycolization catalyst, and finally 0.6 Torr
Deglycolization reaction at 215 to 220 ° C for 8 hours under reduced pressure to obtain a number average molecular weight of 25,100 and a weight average molecular weight of 5
A white waxy aliphatic polyester (A) having a melting point of 114 ° C. of 7,000 was obtained.

Synthesis of polylactic acid (B) Cyclic lactic acid dimer 140 recrystallized three times with chloroform
g was mixed with 0.05 g of dibutyltin dilaurate and 0.02 g of lauryl alcohol and then placed in an ampoule,
Under a reduced pressure of 0.1 Torr, initially 170 ℃, finally 200
Ring-opening polyaddition was carried out at 0 ° C. for 20 hours. This reaction was repeated three times, and the polylactic acid obtained by adding up was crushed, and the unreacted dimer was extracted with acetone, and then dried by heating. Number average molecular weight 102,000, weight average molecular weight about 4
Polylactic acid (B) having a temperature of 80,000, a melting point of 176 ° C. and a crystallization temperature of 109 ° C. was obtained.

100 g of polyester (A) was placed in a 250 cc heating kneader equipped with a synthesis thermometer of block polyester (a) and a gas introduction tube, and the mixture was heated and melted at 190 ° C. in a nitrogen gas stream, and then hexamethylenediene. After adding 1.5 g of isocyanate and kneading for 15 minutes, 50 g of polylactic acid (B) was added and melt-reacted for 30 minutes. The block polymer (a) thus obtained has a number average molecular weight of 52,0.
00, weight average molecular weight 208,500, MFR (190
C., load 2.16 kg) was 10.6 g / 10 minutes, and the melting point was measured by the DSC method. The results were 113.5.degree. C. and 172.9.
Melting points were observed at two places of ° C. The DSC curve of this is shown in FIG. When this block polyester was press-molded at 190 ° C. and uniaxially stretched 3 times at room temperature, the stretchability was good, and the uniaxially stretched film having a thickness of about 55 μ was translucent, and its tensile strength (JIS K6760 was used. The measurement) was 9.2 kg / mm ² .

Example 2 Synthesis of Block Polyester (b) In a thermometer of 500 cc equipped with a gas inlet tube, 100 g of aliphatic polyester (A) and polylactic acid (B) were placed in a heating kneader.
Charge 100 g and 0.05 g of phosphorous acid to obtain 190
After uniformly heating and melting at 0 ° C., 2.6 g of hexamethylene diisocyanate was added and mixed uniformly. No rapid thickening occurred at this point. Next, when 0.1 g of tetraisopropoxy titanium was added, the viscosity increased rapidly, but gelation did not occur. The stirring resistance of the motor of the kneader reached the maximum value approximately 10 minutes after the start of heating and mixing, so the mixing was stopped, and the melt was poured into a metal vat and solidified. The block polyester (b) obtained had a number average molecular weight of 70,100 and a weight average molecular weight of 334,00.
As measured by DSC method at 0, 114 ° C. and 18
Two melting points were shown at 7 ° C. This block polyester (b) was press-molded at 190 ° C. and uniaxially stretched three times at room temperature to obtain a semitransparent stretched film having a thickness of about 50 μ.
The tensile strength of this stretched film was 8.1 kg / mm ² .

Comparative Example 1 In Example 2, 0.05 g of phosphorous acid was not added, the same amount of aliphatic polyester (A) and polylactic acid (B) were simultaneously melted at 190 ° C., and then the same amount of When hexamethylene diisocyanate is added, only polylactic acid (B) rapidly reacts with hexamethylene diisocyanate and gels, and is separated from the aliphatic polyester (A) to obtain a uniform block polyester. There wasn't.

Example 3 Aliphatic Polyester (D) Synthesis In a 1 liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas inlet tube, ethylene glycol 205 g and polyethylene glycol (molecular weight 40
0) 20 g, 354 g of succinic acid, 2 g of glycerin, and 0.06 g of tetraisopropoxytitanium were charged and esterified at 195 to 205 ° C. in a nitrogen gas stream to obtain an acid value of 9.
After setting 4, the final temperature is 0.6To at a temperature of 215 to 220 ° C.
The glycol removal reaction was carried out for 8 hours under reduced pressure of rr. The obtained aliphatic polyester (D) is in the form of a pale yellow wax,
The melting point was 101 ° C., the number average molecular weight was 54,500, the weight average molecular weight was 468,000, and the MFR was 10.9 g / 10 minutes.

Synthesis of Block Polyester (d) A kneader similar to that used in Example 1 was charged with 70 g of aliphatic polyester (D), and the mixture was heated and melted at 190 ° C. in a nitrogen gas stream and then mixed with hexamethylene diisocyanate while kneading. After adding 1 g of nato and further kneading for 15 minutes, polylactic acid was added.
(B) 70 g was added, and the mixture was further kneaded for 30 minutes and homogenized.
The number average molecular weight of the obtained block polyester (d) was 56,400, the weight average molecular weight was 437,000, and MF
R was 15.4 g / 10 minutes. Further, as shown in FIG. 2, two melting points were found at 96.8 ° C. and 165.6 ° C., but the apparent molten state was not observed unless it was 170 ° C. or higher. This block polyester (d) is 19
It was press-molded at 0 ° C. and uniaxially stretched 3 times at room temperature to obtain a stretched film having a thickness of about 40 μ. The tensile strength of this film was 7.9 kg / mm ² , and it was a slightly hazy transparent film.

[0040]

The block polyester obtained according to the present invention has biodegradability and has a high melting point as an aliphatic polyester, but also has thermal stability and good moldability, excellent mechanical strength and physical properties. Is well balanced.

[Brief description of drawings]

FIG. 1 is a diagram showing a DSC measurement result of a block polyester (a) obtained in Example 1.

FIG. 2 is a view showing a DSC measurement result of the block polyester (d) obtained in Example 3.

Claims (4)

[Claims] 1. [I] (1) 1 to 99% by weight of an aliphatic polyester having a melting point of 70 ° C. or higher, a number average molecular weight of 10,000 or higher, and a terminal group substantially a hydroxyl group.
(2) Polylactic acid 99 having a number average molecular weight of 10,000 or more
1% by weight and (3) melt-mixed in the presence of a phosphorus compound, and then [II] with respect to a total of 100 parts by weight of the aliphatic polyester of (1) and the polylactic acid of (2).
A method for producing a block polyester, comprising adding and reacting 0.1 to 5 parts by weight of a polyvalent isocyanate compound so as to have a number average molecular weight of 30,000 or more. 2. The amount of the phosphorus compound used in (3) is (1)
100 total of aliphatic polyester of (2) and polylactic acid of (2)
The method for producing a block polyester according to claim 1, which is 0.001 to 3 parts by weight with respect to parts by weight. 3. The phosphorus compound of (3) is at least selected from the group consisting of phosphoric acid and its alkyl esters, phosphonic acid organic esters, phosphorous acid, organic esters of phosphorous acid, and polyphosphoric acid. The method for producing a block polyester according to claim 1, which is one type of inorganic or organic phosphorus compound. 4. [I] (1) 1 to 99% by weight of an aliphatic polyester having a melting point of 70 ° C. or more, a number average molecular weight of 10,000 or more, and a terminal group being substantially a hydroxyl group, and (2) the number. Polylactic acid 9 having an average molecular weight of 10,000 or more
9 to 1% by weight, based on 100 parts by weight of the total amount of the aliphatic polyester of (1) and the polylactic acid of (2),
[II] When 0.1 to 5 parts by weight of the polyvalent isocyanate compound is added and reacted, the polyvalent isocyanate compound is added and reacted with the aliphatic polyester (1) in a molten state in advance. Add polylactic acid and let it melt,
A method for producing a block polyester, which has a number average molecular weight of 30,000 or more.