JP2001131274A - Preparation process of high-molecular-weight aliphatic polyester polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for preparing a high-molecular-weight aliphatic polyester polymer having a practically sufficient molecular weight and an excellent mechanical strength in the presence of an inexpensive catalyst in an industrially advantageous way. SOLUTION: An aliphatic polyester polymer is prepared by a polycondensation reaction of (i) a mixture of an aliphatic dicarboxylic acid or its diester and an aliphatic diol or (ii) the preparatorily condensed material of the mixture, in the presence of an aluminum catalyst for an ester exchanging reaction and its co-catalyst. As the co-catalyst, a proton-releasing compound is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aliphatic polyester-based polymer and an aliphatic polyester-based polymer obtained by the method.

[0002]

2. Description of the Related Art Synthetic polymers such as polyolefins and aromatic polyesters are used in large quantities as indispensable materials for daily life, but these synthetic polymers are difficult to decompose in the natural environment. In addition, environmental problems have become apparent with the increase in waste polymers. For this reason, biodegradable plastics are being developed, and aliphatic polyesters are receiving attention as biodegradable polymers. However, conventional aliphatic polyesters have many problems to be solved in terms of cost, mechanical strength, and the like. For example, polyhydroxybutyrate is a polyester having a high melting temperature and good performance, but since the difference between the melting temperature and the decomposition temperature is small, it is liable to be thermally decomposed at the time of molding and cause problems such as performance deterioration and odor generation. In addition, since the polymer is produced using a microorganism, productivity is low and cost is high. Polycaprolactone is one of the few aliphatic polyesters that is currently industrially produced, but its use is limited because its melting temperature is only about 60 ° C. Furthermore, polymers of hydroxycarboxylic acids have been attracting attention as polymers with good biodegradability, and in particular, polymers of lactic acid are biocompatible polymers that are used in bioabsorbable materials. Is complicated.

[0003] In order to solve the above-mentioned problems relating to the production and performance of aliphatic polyesters, polyesters obtained by polycondensation of aliphatic dicarboxylic acids or anhydrides thereof with glycols have attracted attention. The method of producing this polyester has been known for a long time, and succinic acid, adipic acid, suberic acid, sebacic acid, dodecadicarboxylic acid, etc. are used as the acid, and ethylene glycol, 1,4-butanediol, 6-cyclohexanediol, 1,
A method using 4-cyclohexanedimethanol or the like has been reported. And it is reported that the melting temperature of the polymer using succinic acid as a raw material is 70 ° C. or higher. However, all of these polymers have a number average molecular weight of about several thousands, and thus do not have a mechanical strength that can be made into a film or a fiber.

Recently, aliphatic polyesters have been spotlighted as biodegradable plastics. Therefore, a number of polyester production methods having a large number average molecular weight and a high mechanical strength have been proposed as described below. However, none of these proposals has problems such as an increase in the number of manufacturing steps, and no satisfactory method can be found. According to JP-A-4-189822 and JP-A-4-189823, an aliphatic polyester having a number average molecular weight of about 15,000 is produced from an aliphatic dicarboxylic acid or a derivative thereof and glycol,
A method of increasing the molecular weight by crosslinking this with diisocyanate is disclosed. However, this method has problems such as formation of a microgel and deterioration of the polymer quality. Also,
JP-A-5-287041 and JP-A-5-2870
According to Japanese Patent No. 42, an aliphatic dicarboxylic acid, glycol and polyvalent isocyanate are copolymerized to obtain a polymer having a high number average molecular weight and a wide molecular weight distribution. This polymer has a high molecular weight, a high mechanical strength, and a high melt viscosity due to a wide molecular weight distribution, and is suitable for producing a molded article such as a film. For the same purpose, JP-A-5-287068 discloses a four-component copolymer obtained by adding 3,3,4,4-benzophenonetetracarboxylic anhydride in addition to the three components described above.
No. 71 proposes a four-component copolymer to which a polyhydric alcohol such as pentaerythritol is added in addition to the above three. However, these copolymers have problems such as formation of a gel. In addition, JP-A-6-192374 discloses that a low molecular weight aliphatic polyester is synthesized from an aliphatic dicarboxylic acid, a glycol and a polyhydric alcohol or a polyhydric carboxylic acid, and a fatty acid having an isocyanate group at the terminal thereof. There has been proposed a method for obtaining a high molecular weight polymer containing no microgel by reacting an aromatic polyester. But,
This method has a disadvantage that the number of manufacturing steps is further increased.

According to JP-A-8-143656, it is possible to improve the biodegradability by copolymerizing an aliphatic dicarboxylic acid diester and an aliphatic glycol with a carbonate compound to obtain an aliphatic polyester carbonate. It has been proposed that the biodegradability can be controlled by changing the copolymerization ratio. However, in the case of this polyester carbonate, the mechanical strength is reduced by copolymerizing the carbonate compound.

On the other hand, in the process for producing an aliphatic polyester polymer, a general catalyst for transesterification such as a titanium catalyst such as titanium tetraisopropoxide is used (US Pat. No. 5,504,148 (199)).
6)). However, Ti is an expensive metal, and it is desired to develop a cheaper catalyst in order to expand needs for aliphatic polyester-based plastics. In the case of an aliphatic biodegradable plastic that is decomposed in an environment such as soil, it is necessary to consider the effect of the catalyst component contained in the plastic on the environment. Soil contains aluminum oxide as a main component, and the use of an Al-based catalyst that is mineralized into Al oxide is significant from the viewpoint of environmental conservation.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a method for producing a high-molecular-weight aliphatic polyester polymer having a sufficient molecular weight for practical use and excellent mechanical strength in the presence of an inexpensive catalyst. An object of the present invention is to provide a method for producing it advantageously and a polymer obtained therefrom.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, (i) a mixture of an aliphatic dicarboxylic acid or a diester thereof and an aliphatic diol or (ii) a precondensate of the mixture is used as a reaction raw material, and the reaction raw material is used as an aluminum for transesterification reaction. The present invention provides a process for producing an aliphatic polyester-based polymer, which comprises conducting a polycondensation reaction in the presence of a system catalyst and its cocatalyst, wherein a proton releasing compound is used as the cocatalyst. Further, according to the present invention, (i) an oxycarboxylic acid-based compound or (ii) a precondensate thereof is used as a reaction raw material, and the reaction raw material is subjected to polycondensation in the presence of an aluminum-based catalyst for a transesterification reaction and a cocatalyst. A method for producing an aliphatic polyester-based polymer, which comprises reacting a proton-releasing compound as the promoter. Further, according to the present invention, there is provided an aliphatic polyester-based polymer obtained by the above method.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION To produce a polymer of the present invention,
An aliphatic dicarboxylic acid or a diester thereof is used as a main reaction material. This is represented by the following general formula (1)
It is represented by

Embedded image R ²¹ OOC— (R ¹¹ ) _t —COOR ²¹ (1) In the above formula, R ¹¹ has 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms.
Represents a divalent aliphatic group. The divalent aliphatic group can be linear or cyclic, and can be saturated or unsaturated. Further, the divalent aliphatic group may contain a hetero atom such as oxygen in addition to carbon in the main chain. Preferred divalent aliphatic groups used in the present invention,
Examples thereof include an alkylene group or alkenylene group which may have an ether bond having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, an alkyleneoxy group or an oxyalkylene group. When showing a specific example of the divalent aliphatic group, -CH ₂ -, - C ₂
H ₄ —, —CH ₂ O—, —CH ₂ OCH ₂ —, —C ₃ H ₆ —,
_{-C 4 H 2 -, - C} 6 H 12 -, - C 3 H 16 -, - C 12 H
_{24 -, - C 12 H 22} - , and the like. t represents zero or a number of 1. When t is zero, the dicarboxylic acid component represented by the general formula (1) is oxalic acid (HOOC-COO).
H), and when t is 1, the dicarboxylic acid component is R
A dicarboxylic acid represented by ²¹ OOC-R ¹¹ -COOR ²¹ or an ester thereof is shown. In the general formula (1), R ²¹ represents hydrogen, a lower alkyl group or an aryl group. Examples of the lower alkyl group include an alkyl group having 1 to 6, preferably 1 to 4 carbon atoms. The aryl group has 6 to 10 carbon atoms, preferably 6 to 8 carbon atoms, such as a phenyl group. Examples of the aliphatic dicarboxylic acid include oxalic acid, succinic acid, adipic acid, suberic acid, sebacic acid, dodecanoic acid, diglycolic acid, and the like.

In producing the polymer of the present invention, an aliphatic diol is used as a main reaction material. This is represented by the following general formula (2).

Embedded image HO-R¹²—OH (2) In the above formula, R¹²Has 1 to 12 carbon atoms, preferably 2 to 10 carbon atoms.
Represents a divalent aliphatic group. In this case, the divalent aliphatic group has a chain
Or cyclic, and can be saturated or unsaturated.
It can be Japanese. In addition, this divalent aliphatic
The group has a hetero atom such as oxygen in addition to carbon in its main chain.
It can also be contained. Preferred divalent fat used in the present invention
The aliphatic group has 1 to 12 carbon atoms, preferably 2 to 10 carbon atoms.
Alkylene group or alkene which may contain a ter bond
Nylene group, alkyleneoxy group or oxyalkylene
And the like. As a specific example, -CH_Two-, -C_TwoH
_Four-, -C_ThreeH₆-, -C_FourH₈-, -C₆H₁₂-, -C₈H
₁₆-, -C₁₂H_{twenty four}-, -C₁₂H _{twenty two}-(Dodecenyl),-
C₆H_Ten-(Cyclohexenyl), -CH_TwoO-, -CH
_TwoOCH_Two-And the like. As a concrete example,
For example, ethylene glycol, diethylene glycol,
Pyrene glycol, dipropylene glycol, 1,4-
Butanediol, 1,6-hexanediol, 1,4-
Cyclohexanedimethanol, polyethylene glycol
And polypropylene glycol.

In the present invention, if necessary, at least two functional groups reactive with the fatty acid dicarboxylic acid or its diester and / or aliphatic diol may be added to the reaction raw material as an auxiliary component. At least one compound selected from the aliphatic and / or aromatic compounds contained therein can be added. Such auxiliary components include oxycarboxylic acid compounds, carbonates, trihydric or higher polyhydric alcohols, polyoxyalkylene glycols, and the like.

The oxycarboxylic acid compounds include compounds represented by the following general formulas (3) and (4).

Embedded image HO—R ¹³ —COOR ²² (3)

Embedded image In the general formula (3), R ¹³ has 1 to 10 carbon atoms;
It preferably represents 2 to 8 divalent aliphatic groups. In this case, the divalent aliphatic group can be any of those described for R ¹¹ and R ¹² . R ²² represents hydrogen, a lower alkyl group or an aryl group. Examples of the lower alkyl group include an alkyl group having 1 to 6, preferably 1 to 4 carbon atoms. Examples of the aryl group include those having 6 to 10 carbon atoms, preferably 6 to 8 carbon atoms, such as a phenyl group. Examples of the oxycarboxylic acid (3) include glycolic acid, lactic acid,
Examples include hydroxyalkyl acids, α-oxy acids, butyric acid, and the like. Further, the oxycarboxylic acid may be a cyclic diester having two molecules bonded thereto. Specific examples include those obtained from glycolic acid (glycolide)
And those obtained from lactic acid (lactide).

In the above general formula (4) representing a lactone compound, R ¹³ has 2 to 10 carbon atoms, preferably 2 to 5 carbon atoms.
Represents a linear or cyclic divalent aliphatic group. In this case, the divalent aliphatic group includes a saturated or unsaturated alkylene group. Examples of the lactone include caprolactone, valerolactone, laurolactone and the like.

The carbonate ester is represented by the following general formula (5).

Embedded image R ²³ OCOOR ²⁴ (5) In the above formula, R ²³ and R ²⁴ represent a lower alkyl group or an aryl group, and when R ²³ and R ²⁴ are both lower alkyl groups, they are linked to each other. A ring may be formed. Examples of the lower alkyl group include an alkyl group having 1 to 6, preferably 1 to 4 carbon atoms. As the aryl group, C6 to C6
10, preferably 6 to 8, such as a phenyl group.

The polyhydric alcohol is an aliphatic compound having three or more hydroxyl groups. Such polyhydric alcohols include glycerin, diglycerin, polyglycerin compounds, pentaerythritol and the like. The upper limit of the number of hydroxyl groups contained in the polyhydric alcohol is not particularly limited, but is usually about 6.

The polyglycerin compound is represented by the following general formula (6).

Embedded image HO— [C ₃ H ₅ (OR ¹⁴ ) O] _n —H (6) In the formula, R ¹⁴ represents hydrogen or an acyl group, and n represents an average degree of polymerization of glycerin. The acyl group includes an aliphatic acyl group represented by the following general formula (7).

Embedded image R ²⁵ CO- (7) the formula, R ²⁵ is an aliphatic group, the number of carbon atoms from 1 to 2
0, preferably 1 to 12, preferably 1 to 6. Specific examples include methyl, ethyl, propyl, butyl, hexyl, dodecyl, octadecyl and the like. The average degree of polymerization n of glycerin is 2 or more, and the upper limit is 30.
It is about. Generally, n is 2-10.

The polyoxyalkylene glycol is
It is represented by the following general formula (8).

HO- (AO) _m -H (8) In the above formula, AO represents an alkyleneoxy group having 2 to 4 carbon atoms, and specific examples thereof include ethyleneoxy, propyleneoxy, butyleneoxy, and a mixed alkyleneoxy thereof. M represents an average degree of polymerization of (AO), and represents a number of 2 to 10, preferably 2 to 5.

In the present invention, in addition to the above-mentioned compounds, oxypolycarboxylic acids such as malic acid and citric acid, diisocyanates, orthoformate, terephthalic acid, polyethylene terephthalate and the like can be used as auxiliary components.

The auxiliary component is used for the purpose of controlling the biodegradability and physical properties of the produced polymer. Its usage is
The molar fraction is 0.3 or less, preferably 0.2 or less, based on all monomer components such as dicarboxylic acids and diesters contained in the resulting polymer.

In the reaction raw material comprising a mixture of the aliphatic dicarboxylic acid or the diester thereof, the aliphatic diol and the optional auxiliary component used in the present invention, the proportion of the aliphatic diol used is included in the reaction raw material. The ratio is 1 to 2 mol, preferably 1.01 to 1.6 mol, per 1 mol of all carboxylic acids or diesters thereof.

The proportion of the oxycarboxylic acid-based compound used in the present invention is determined by the molar ratio of the ester portion (oxycarboxylic acid ester portion) derived from the oxycarboxylic acid-based compound to the total ester portion contained in the resulting polymer. The ratio is such that the fraction is in the range of 0.02 to 0.3, preferably 0.05 to 0.2.

The proportion of the carbonate ester used in the present invention is such that the mole fraction of the ester portion (carbonate portion) derived from the carbonate ester to the total ester portion contained in the produced polymer is 0.02 to 0%. 0.3, preferably 0.
The ratio is in a range of from 0.5 to 0.2.

The proportion of the oxycarboxylic acid compound used in the present invention, such as glycolic acid, diglycolic acid or an ester thereof, is derived from the oxycarboxylic acid compound with respect to all the ester portions contained in the resulting polymer. The molar ratio of the ester moiety is in the range of 0.02 to 0.3, preferably 0.05 to 0.2.

The use ratio of the polyhydric alcohol used in the present invention is such that the mole fraction of the ester portion derived from the polyhydric alcohol with respect to the total ester portion contained in the produced polymer is 0.0005 to 0.005; Preferably 0.001
The ratio is in the range of 0.004 to 0.004.

In the case of terephthalic acid or polyethylene terephthalate used as an auxiliary component in the present invention, the molar ratio of terephthalic acid units to all ester parts is 0.01 to 0.35, preferably 0.05 to 0. .20
It is a ratio that falls within the range.

The reaction raw material used in the present invention can be composed of at least one selected from the oxycarboxylic acid compounds represented by the general formulas (3) and (4). This reaction raw material contains at least one selected from aliphatic and / or aromatic compounds containing at least two functional groups reactive with the oxycarboxylic acid compound, if necessary. can do. The auxiliary components include carbonate esters, trihydric or higher polyhydric alcohols, polyoxyalkylene glycols, and the like. Specific examples thereof include those described above. In addition, malic acid,
Oxypolycarboxylic acids such as citric acid, diisocyanate, orthoformate, terephthalic acid, polyethylene terephthalate and the like can be used. The auxiliary component is used for the purpose of controlling the biodegradability and physical properties of the produced polymer. The amount used is such that the molar ratio with respect to all the monomer components contained in the resulting polymer is 0.3 or less, preferably 0.2 or less.

In the present invention, when a polycondensation reaction is carried out on the reaction raw materials, a catalyst for an aluminum-based transesterification reaction is used, and a proton-releasing compound is used as a co-catalyst thereof. The proton releasing compound means a compound capable of releasing a proton (H ⁺ ) in water. As such a substance, various kinds of conventionally known substances such as a protonic acid and a derivative thereof can be used.
(Ii) a silicate represented by the following general formula (II), (iii) phosphoric acid, (iv) ammonium hydrogen phosphate, (v) a sulfonic acid group or a sulfate group. At least one compound selected from aliphatic and / or aromatic compounds and (vi) sulfuric acid can be preferably used. _{O = P (OH) 2 R} 1 , or ^{O = P (OH) R 2} 2 (I) ( wherein, R ¹ and R ² represents an aliphatic group or an aromatic _{^{group) (R 3 O) 2 SiR}} 4 ₂ (II) (wherein, R ³ and R ⁴ represent an aliphatic group or an aromatic group) In the above general formula (I) representing an organic phosphonic acid, the aliphatic group may be a linear or cyclic aliphatic group And the number of carbon atoms is 1 to 12, preferably 1 to 10. The aromatic group has 6 to 12 carbon atoms, preferably 6 to 10 carbon atoms.
Aryl group having 7 to 12 carbon atoms, preferably 7 to 10 carbon atoms
Aralkyl groups are included. Specific examples of the organic phosphonic acid include phenylphosphonic acid, benzylphosphonic acid, methylphosphonic acid, n-butylphosphonic acid, and cyclohexylphosphonic acid. In the general formula (II) representing a silicate ester, the aliphatic group includes a chain and a cyclic group, and has 1 to 12, preferably 1 to 10 carbon atoms. The aromatic group includes an aryl group having 6 to 12 carbon atoms, preferably 6 to 10 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, preferably 7 to 10 carbon atoms. Specific examples of the silicate ester include dimethoxydiphenylsilane, dimethoxydimethylsilane, diphenoxydiethoxysilane, and the like.

The above-mentioned phosphoric acid (O = P (OH) ₃ ) or a compound which generates phosphoric acid in the reaction system is included. Examples of the ammonium hydrogen phosphate include ammonium monohydrogen phosphate and ammonium dihydrogen phosphate.

In the aliphatic and / or aromatic compounds having a sulfonic acid group or a sulfate group, examples of the aliphatic group and the aromatic group include those described for the organic phosphonic acid. Specific examples of such a protonic acid include p-toluenesulfonic acid, dimethyl sulfate, diethyl sulfate, and ethyl sulfate.

The compound used as a co-catalyst in the present invention exhibits an excellent action as a co-catalyst component for producing an aliphatic polyester-based polymer. Can be manufactured. In the case of an aliphatic biodegradable plastic that is decomposed in an environment such as soil, it is necessary to consider the effect of the catalyst component contained in the plastic on the environment. Soil contains aluminum oxide as a main component, and the use of an aluminum-based catalyst that is mineralized into aluminum oxide is significant from the viewpoint of environmental conservation.

The amount of the cocatalyst used in the present invention is 0.005 to 2, preferably 0.01 to 1.1, in molar ratio to the aluminum catalyst.

As the aluminum catalyst (esterification catalyst) for the transesterification reaction used in the present invention, various conventionally known catalysts can be used. Examples of such an aluminum-based catalyst include aluminum laurate, aluminum lactate, hydroxyaluminum diacetate, hydroxyaluminum dicyclohexane butyrate, aluminum dicarboxylate such as aluminum dihydroxystearate, aluminum triethoxide, aluminum triisopropoxide, and aluminum. In addition to aluminum alcoholates such as tri-tert-butoxide and aluminum phenoxide, aluminum acetylacetonate and the like can be mentioned.

These aluminum-based catalysts for transesterification may be used alone or in combination of one or more of conventionally known titanium, iron, zinc and the like. The aluminum-based catalyst is used in an amount of 10 ^{−7 with} respect to 1 mol of the total amount of the carboxyl group-containing compound contained in the reaction raw material.
It is preferably used in a proportion of 10 ⁻² mol, preferably 10 ^{−4 to} 5 × 10 ⁻³ mol. If the amount of the catalyst is less than this range, the reaction does not proceed well and the reaction requires a long time.
If it exceeds this range, it causes thermal decomposition and cross-linking of the polymer at the time of polymerization, and also causes thermal decomposition and the like in molding of the polymer, which is not preferable.

In one method for producing an aliphatic polyester-based polymer according to the present invention, a reaction raw material is heated in the presence of an aluminum-based catalyst for a transesterification reaction and its cocatalyst to cause a polycondensation reaction. In this reaction, water and OH-containing compounds (such as alcohol) are by-produced.
The reaction temperature is determined when the reaction by-product is methanol.
The reaction temperature under normal pressure is 100 to 300 ° C, preferably 1 to 300 ° C.
20-250 ° C. When the by-product is water, the reaction temperature under normal pressure is 130 to 300 ° C, preferably 145 ° C.
２５０250 ° C. The reaction pressure is normal pressure, reduced pressure or slightly increased pressure, but is preferably normal pressure. In the present invention, by-products generated in the reaction are removed from the reaction system. To this end, the reaction is carried out under conditions of temperature and pressure at which water or an OH-containing compound as a by-product is maintained in a gas phase, and the by-product in the gas phase is reduced in pressure in the reaction system. The gas is discharged from the reaction system by flowing nitrogen gas. In addition, the reaction is performed using a reactor (reactive distillation column) to which a distillation column is connected, and by-products produced by the reaction are continuously discharged from the distillation column. In such a reaction, in order to efficiently obtain a high molecular weight polymer, the reaction proceeds to a certain extent, and when 90% of the calculated amount of by-products (water or alcohol such as methanol) is obtained, the reaction is stopped. It is preferable to conduct polycondensation while removing the aliphatic diol by changing the reaction conditions such as raising the temperature or reducing the pressure.
The reaction conditions in this case are conditions in which the aliphatic diol to be eliminated exists as a gas, and can be formed by adjusting the temperature and pressure.

Another method for preferably producing an aliphatic polyester polymer according to the present invention is a pre-polycondensation step (first method).
Step) and a step of increasing the molecular weight of the preliminary polycondensate (second step). In the preliminary polycondensation step, the reaction raw material is subjected to a polycondensation reaction in the presence of the aluminum-based catalyst and its cocatalyst. The reaction temperature is the temperature at which by-products produced by the reaction exist as gases in the reaction system. The reaction pressure is normal pressure, reduced pressure or slightly increased pressure, but is preferably normal pressure. By-products generated in this reaction are removed from the reaction system. In this reaction, when the by-product (water or alcohol) in the reaction product is obtained at 70 to 97%, preferably 90 to 95% of the calculated amount, the reaction temperature is raised and polycondensation is performed under reduced pressure. The pre-polycondensation time in this case is 1 hour to 5 hours. As a method for charging the co-catalyst, a method in which the co-catalyst is charged in the presence of the catalyst at the start of the precondensate (oligomer) formation reaction is preferable.

Next, in order to carry out a high molecular weight reaction of the pre-polycondensation reaction product obtained as described above, the reaction is carried out with or without the addition of an aluminum-based catalyst for transesterification to the reaction product. continue. This high molecular weight process is a process in which aliphatic glycol bonded to the terminal of the low molecular weight condensate is condensed while elimination to form a high molecular weight condensate. By this process, the number average molecular weight is 4 More than 10,000 condensates can be produced. The reaction conditions in this case may be any conditions under which the by-produced aliphatic glycol can exist as a gas. This high molecular weight process can be carried out in the same apparatus as the reaction apparatus for carrying out the preliminary polymerization step or in a polymerization apparatus having high stirring efficiency. When the same apparatus is used, after the completion of the precondensation reaction, the reaction conditions may be changed, for example, the reaction temperature may be increased and the reaction pressure may be decreased to carry out the condensation reaction of the precondensate. The reaction pressure is from normal pressure to reduced pressure, but it is preferable to use reduced pressure. When employing reduced pressure, the pressure is typically
It is 0.005 to 5 Torr, preferably 1 Torr or less. The lower limit of the pressure is not particularly limited, but is usually about 0.01 to 1 Torr. The reaction time is about 2 to 60 hours.

The molar ratios of the reaction raw materials such as the aliphatic dicarboxylic acid component and the aliphatic diol component in the reaction raw materials in the present reaction are as follows. 1.0 ≦ (B) / (A) ≦ 1.6 0.02 ≦ (C + D) / (A + C) ≦ 0.30 0.02 ≦ (A + D) / (A + C) ≦ 0.20 In the above formula, A) is the number of moles of an aliphatic dicarboxylic acid or an ester thereof, (B) is the number of moles of an aliphatic diol, C is the number of moles of an oxycarboxylic acid compound and a carbonate compound, and D is an auxiliary component. The number of moles of a carboxyl group-containing compound such as terephthalic acid is shown.

One embodiment of the polymer of the present invention is represented by the following general formula (9)

Embedded image (—CO— (R ¹¹ ) _t —CO—O—R ¹² —O—) (9) It contains an ether group-containing ester moiety represented by the following general formula (10)

Embedded image (—CO—R ¹³ —O—) (10) The oxycarboxylic acid ester moiety represented by
01 to 0.3, preferably 0.05 to 0.2, and / or the following general formula (11)

Embedded image (—OCOO—) The carbonate portion represented by the formula (11) has a mole fraction of 0.01 to 0.1.
3, preferably in a ratio of 0.05 to 0.2.

Another embodiment of the polymer of the present invention is represented by the following general formula (12)

Embedded image (—CO—R ¹³ —O—) An oxycarboxylic acid ester moiety represented by the following formula (12), and the following general formula (13)

Embedded image (—OCOO—) The carbonate portion represented by the formula (13) has a mole fraction of 0.01 to 0.1.
3, preferably in a ratio of 0.05 to 0.2.

The polymer of the present invention has a substantially linear structure and no gel structure, and has a number average molecular weight of 20,000 or more, preferably 40,000 or more. The upper limit of the number average molecular weight is about 180,000. The polymer of the present invention is a polymer having good chemical recyclability since it has biodegradability and can recover raw materials by alcohol decomposition or hydrolysis.

[0041]

Next, the present invention will be described specifically with reference to examples and comparative examples. Various physical property values of the aliphatic polyester were measured by the following methods. (Molecular weight and molecular weight distribution) A calibration curve was prepared from standard polystyrene using gel permeation chromatography (GPC), and the number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) were determined. Was. As an eluent, chloroform was used. (Thermal Properties) The melting temperature and the glass transition point were determined by a differential scanning calorimeter (DSC). The thermal decomposition temperature was determined by a thermogravimetric analyzer (TG).

Example 1 180 mmol of succinic acid, 0.04 mmol of phosphoric acid, 0.04 mmol of phosphoric acid,
189 mmol of butanediol and 0.12 mmol of Al isopropoxide were charged, and the reaction was started at 140 ° C. under a nitrogen atmosphere, and the temperature was gradually raised to 240 ° C. to discharge water (about 1 hour). Then, the pressure was gradually reduced while stirring, and the reaction was continued at 0.1 Torr for 5.5 hours. After the reaction, the molecular weight of the obtained polymer was measured.
Mw / Mn was 1.64.

Example 2 A 100-ml four-necked flask equipped with stirring blades was charged with 180 mmol of succinic acid, 184 mmol of 1,4-butanediol, 0.12 mmol of Al isopropoxide, and 0.04 mmol of phosphoric acid. The reaction was started at 140 ° C. in a nitrogen atmosphere, the temperature was gradually raised to 240 ° C., and water was discharged (about 1 hour). Then, the pressure was gradually reduced while stirring, and the reaction was continued at 0.1 Torr for 5.0 hours. After the reaction, the molecular weight of the obtained polymer was measured.
Mw / Mn was 16.9 with 66,000 and Mw of 112,000.

Comparative Example 1 180 mmol of succinic acid, 184 mmol of 1,4-butanediol, and 0.12 mmol of Al isopropoxide were charged into a four-necked flask having an inner volume of 100 ml with stirring blades.
When polycondensation was carried out under the same conditions as in Example 2, the reaction time was 6.5 hours, the molecular weight was Mn 64,000, and the weight average molecular weight was M.
w 103,000, and Mw / Mn 1.61. When phosphoric acid was not used as a cocatalyst for the Al catalyst, the reaction time was longer and the molecular weight was lower than in Example 2.

Comparative Example 2 180 mmol of succinic acid, 184 mmol of 1,4-butanediol, 0.12 mmol of Al isopropoxide and 0.60 mmol of phosphoric acid were charged into a 100 ml four-necked flask equipped with stirring blades. The reaction was started at 140 ° C. in a nitrogen atmosphere, the temperature was gradually raised to 240 ° C., and water was discharged (about 1 hour). Subsequently, the pressure was gradually reduced while stirring, and the reaction was continued at 0.1 Torr for 29 hours. After the reaction, the molecular weight of the obtained polymer was measured.
42,000, Mw 72,000, and Mw / Mn was 1.73. When an excess phosphorus compound was used as a cocatalyst with respect to the Al catalyst, the reaction time was longer and the molecular weight was lower than in Example 2.

Example 3 180 mmol of succinic acid, 184 mmol of 1,4-butanediol, 0.12 mmol of Al isopropoxide and 0.04 mmol of ammonium dihydrogen phosphate were placed in a 100 ml four-necked flask equipped with stirring blades. The reaction was started at 140 ° C. in a nitrogen atmosphere, and the temperature was gradually raised to 240 ° C. to drain water (about 1 hour). Then, the pressure was gradually reduced while stirring, and the reaction was continued at 0.1 Torr for 5.3 hours. After the reaction, the molecular weight of the obtained polyester was measured to be Mn 70,000, and Mw / Mn was 1.6.
Nine.

[0047]

The aliphatic polyester polymer of the present invention has an increased heat resistance (melting temperature),
It has good mechanical strength and workability, and can be advantageously used as a molding material. In addition, since a high molecular weight polymer can be synthesized by using an inexpensive Al-based catalyst, there is an effect of improving the production cost. Moreover, this high molecular weight aliphatic polyester has biodegradability and chemical recyclability based on the aliphatic ester bond.

Continuing from the front page (72) Inventor Takashi Masuda 1-1-1, Higashi, Tsukuba, Ibaraki Pref., National Institute of Advanced Industrial Science and Technology (72) Inventor: Amin Sato 1-1-1, Higashi, Tsukuba, Ibaraki Pref. Within the Technical Research Institute (72) Inventor Kazuo Nakayama 1-1-1, Higashi, Tsukuba-shi, Ibaraki Pref. CA06 CB06A CF07 EA02 EA03 EA05 EG07 EG09 EG10 EH02 EH03 FC01 FC03 FC08 FC16 FC17 HC04A HC05A HC06 JA191 JA251 JA261 JB131 JB171 JB182 JC152 JC351 JC361 JC591 JC711 JE162 JF221

Claims (13)

[Claims] 1. Use of (i) a mixture of an aliphatic dicarboxylic acid or a diester thereof and an aliphatic diol or (ii) a precondensate of the mixture as a reaction raw material, wherein the reaction raw material is used as an aluminum-based catalyst for transesterification reaction. A method for producing an aliphatic polyester-based polymer, which comprises conducting a polycondensation reaction in the presence of the cocatalyst, wherein a proton releasing compound is used as the cocatalyst. 2. The method according to claim 1, wherein the proton releasing compound is (i) an organic phosphonic acid represented by the following general formula (I), (ii) a silicate ester represented by the following general formula (II), or (iii) phosphoric acid ,
2. The compound according to claim 1, which is at least one compound selected from (iv) ammonium hydrogen phosphate, (v) an aliphatic compound and / or an aromatic compound having a sulfonic acid group or a sulfate group, and (vi) sulfuric acid. the method of. _{O = P (OH) 2 R} 1 , or ^{O = P (OH) R 2} 2 (I) ( wherein, R ¹ and R ² represents an aliphatic group or an aromatic _{^{group) (R 3 O) 2 SiR}} 4 ₂ (II) (wherein, R ³ and R ⁴ represent an aliphatic group or an aromatic group) 3. The method according to claim 1, wherein the molar ratio of the promoter to the aluminum-based catalyst is in the range of 0.005 to 2. 4. The reaction raw material comprises (i) an aliphatic dicarboxylic acid or a diester thereof, an aliphatic diol and an auxiliary component, wherein the auxiliary component is the aliphatic dicarboxylic acid or a diester thereof and / or the aliphatic A mixture of at least one selected from aliphatic and / or aromatic compounds containing at least two functional groups reactive with a diol, or (ii) a precondensate of the mixture. Item 1. The method according to any one of Items 1 to 3. 5. The method according to claim 4, wherein the auxiliary component is at least one selected from the group consisting of an oxycarboxylic acid compound, a carbonate ester, a trihydric or higher polyhydric alcohol and a polyoxyalkylene glycol. 6. The method according to claim 1, wherein the ratio of the auxiliary component is in a range of 0.3 or less in terms of a molar ratio with respect to all monomer components contained in the produced polymer. 7. A method in which (i) an oxycarboxylic acid-based compound or (ii) a precondensate thereof is used as a reaction raw material, and the reaction raw material is subjected to a polycondensation reaction in the presence of an aluminum-based catalyst for a transesterification reaction and a cocatalyst. A method for producing an aliphatic polyester polymer, wherein a proton releasing compound is used as the cocatalyst. 8. The proton-releasing compound includes (i) an organic phosphonic acid represented by the following general formula (I), (ii) a silicate ester represented by the following general formula (II), and (iii) phosphoric acid ,
8. A compound selected from (iv) ammonium hydrogen phosphate, (v) an aliphatic compound and / or an aromatic compound having a sulfonic acid group or a sulfuric ester group, and (vi) at least one compound selected from sulfuric acid. the method of. _{O = P (OH) 2 R} 1 , or ^{O = P (OH) R 2} 2 (I) ( wherein, R ¹ and R ² represents an aliphatic group or an aromatic _{^{group) (R 3 O) 2 SiR}} 4 ₂ (II) (wherein, R ³ and R ⁴ represent an aliphatic group or an aromatic group) 9. The method of claim 6, wherein the molar ratio of the cocatalyst to the aluminum-based catalyst is in the range of 0.005 to 2. 10. The reaction raw material comprises (i) an oxycarboxylic acid compound and an auxiliary component, and the auxiliary component contains at least two functional groups reactive with the oxycarboxylic acid compound. 10. The method according to claim 8, which is a mixture of at least one selected from aliphatic and / or aromatic compounds or (ii) a precondensate of the mixture. 11. The method according to claim 10, wherein the auxiliary component is at least one selected from a carbonic ester, a trihydric or higher polyhydric alcohol and a polyoxyalkylene glycol. 12. The method according to claim 10, wherein the ratio of the auxiliary component is 0.3 or less in a molar ratio to the oxycarboxylic acid-based compound. 13. An aliphatic polyester-based polymer obtained by the method according to claim 1.