JP2997756B2 - High molecular weight aliphatic polyester copolymer and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high molecular weight aliphatic polyester copolymer and a method for producing the same. More specifically, the present invention has practical physical properties capable of forming and processing, and is biodegradable by microorganisms in soil or water. TECHNICAL FIELD The present invention relates to an aliphatic polyester copolymer and a method for producing the same.

[0002]

2. Description of the Related Art Plastics are characterized in that they are light and durable and hard to disassemble. In particular, general-purpose plastics are industrially mass-produced, widely used in daily life and in the industrial field, and the amount of use thereof is increasing remarkably.
Many plastics do not break down in the natural environment,
In recent years, environmental destruction due to plastic disposal has become a problem. Therefore, development of a biodegradable polymer that can be decomposed by microorganisms in the environment has recently been required.

[0003] Recently, some promising biodegradable aliphatic polyesters have been developed, but each has the following problems. A variety of microorganism-produced aliphatic polyesters represented by polyhydroxybutyrate (PHB) have been developed. However, at this stage, the productivity is low and the cost is high, and they are being studied as medical materials. Further, PHB has a small temperature difference between the melting point and the thermal decomposition temperature, so that thermal decomposition during molding processing becomes a problem. Polycaprolactone is one of the few industrially produced aliphatic polyesters and a biodegradable polymer. However, its melting point is as low as 60 ° C., so there is a problem in heat resistance, and its use is limited. Polylactide is used in the medical field as a bioabsorbable material. However, the raw materials of lactic acid and glycolic acid are expensive, and the polymer production process involves the synthesis of low molecular weight polymers by dehydration, the production of lactide by thermal decomposition, and the synthesis of high molecular weight polymers by ring-opening polymerization of lactide. The resulting polymers are expensive due to their complexity. Recently, a method for directly producing a high molecular weight polymer from lactic acid has been reported (Japanese Patent Application Laid-Open No. 6-65360). A process is required and the manufacturing process is still complicated.

[0004] Numerous synthetic studies have been reported on aliphatic polyesters produced by the polycondensation of α, ω-aliphatic diols with α, ω-aliphatic dicarboxylic acids (Journal of American Chemical Society, 51, 2560 pac, (1929), 54, 15
P. 59 (1932), Dee Macromolecule Chemie, volume 5, page 5, (1950)). However, aliphatic polyesters are synthesized by a dehydration condensation reaction and a diol removal reaction using an aliphatic dicarboxylic acid and an excess diol as starting materials, so that water and diol generated by a dehydration reaction and a diol removal reaction can be efficiently removed from the reaction system. If not sufficiently removed, the reaction will be in an equilibrium state and the molecular weight cannot be increased. Also, since the polycondensation reaction is performed at a high temperature,
Molecular weight reduction occurs due to thermal decomposition of the polymer. In addition, when the amount of the catalyst is increased, in addition to the thermal decomposition reaction, coloring is promoted, and crosslinking of the aliphatic polyester occurs, resulting in a crosslinked polymer having a large apparent molecular weight and a large molecular weight distribution. Would. From this, linear polymers have hitherto been used in the range of 6,000 to 10,000.
A molecular weight of only about 000 was obtained, which was not sufficient for processing as a fiber or film.

[0005] In order to improve the molecular weight of these aliphatic polyesters, it has been reported to link them with diisocyanates such as hexamethylene diisocyanate (Polymer Journal, Vol. 2, p. 387, 1971).
And JP-A-4-189822). However, the method using these linking agents is complicated in operation such as the need to make the molecular weight of the prepolymer uniform and the need to add the linking agent during the polymerization reaction. Further, there is a problem in the molding process because the polymer chain has a urethane bond other than an ester bond, and furthermore, coloring and formation of a microgel are observed as physical properties of the polymer.

As described above, the aliphatic polyester obtained by the polycondensation method has the above-mentioned problems in the synthesis method and physical properties. Therefore, the aliphatic polyester is a high molecular weight polymer (polymer).
Widely used as a low molecular weight polymer (oligomer) or as a reactive oligomer having a functional group such as a hydroxyl group at both terminals in additives such as plasticizers and lubricating oils, and as a base resin for paints and adhesives. I came. Therefore, industrially, in contrast to the studies on aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, studies on the production of aliphatic polyesters with a high molecular weight have hardly been studied.

Several studies have been made on the evaluation of biodegradability of polymers. Decomposition of aliphatic polyesters, especially low molecular weight aliphatic polyesters derived from aliphatic dicarboxylic acids and aliphatic diols by polycondensation, such as polyethylene adipate and polybutylene adipate, by mold (Journal of Fermental Technology, Vol. 52, p. 393) (1
974)) and enzymatic degradation (Polymer Science Technology, Vol. 3, p. 61 (1973), Agriculture and Biological Chemistry 41)
Volume, 265 pages (1977), 42 volumes, 1071 pages (19
78)) There is a report on microbial degradation, and attention has been paid to biodegradable polymers. However, there is no report on the biodegradability of high molecular weight polymers.

[0008] From a practical point of view, controlling biodegradability is an important issue. However, polymers such as polyethylene adipate and polycaprolactone, which have low melting points (around 60 ° C.) and poor heat resistance, are not practical as industrial materials, but tend to have a high biodegradation rate, It can be said that the polymer has excellent properties. On the other hand, a polymer having a high melting point (100 ° C. or higher) such as polybutylene succinate can be expected to be practically useful, but has a low biodegradation rate. . In this way, improving the heat resistance of the material, increasing the strength, and increasing the biodegradation rate do not match, so at this stage the biodegradation rate can be freely controlled and adjusted, and the biodegradability is also excellent. No polymer has been found so far, and its development is awaited.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art. That is, an object of the present invention is to provide a high molecular weight aliphatic polymer which is a material which can be formed into a film or a fiber and has practical physical properties and biodegradability, and a method for producing the same.

[0010]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that aliphatic dicarboxylic acid or fatty acid dicarboxylic acid diester as raw materials, aliphatic diol, oxycarboxylic acid It has been found that a high-molecular-weight aliphatic polyester copolymer can be produced by reacting an oxycarboxylic acid ester or a lactone at a specific ratio, thereby completing the present invention. That is, according to the present invention, the general formula (1)

Embedded image (OC—R ₁ —COO—R ₂ —O) _p (1) (wherein, R ₁ is a divalent aliphatic group having 1 to 12 carbon atoms, and R ₂ is a divalent aliphatic group having 2 to 12 carbon atoms. A valent aliphatic group, p represents a mole fraction of the ester moiety represented by the general formula (1) contained in the polyester copolymer), and an ester moiety represented by the general formula (2)

Embedded image (OC—R ₃ —O) _q (2) (wherein R ₃ is a divalent aliphatic group having 1 to 10 carbon atoms, and is a 3-hydroxyaliphatic carboxylic acid or 4-hydroxy Divalent aliphatic groups derived from aliphatic carboxylic acids are not included,
q represents a mole fraction of the ester portion represented by the general formula (2) contained in the polyester copolymer), and the value of q is 0.02 to 0.3.
A biodegradable high molecular weight aliphatic polyester copolymer having a number average molecular weight of 18,000 or more in the range of 0 is provided. Further, according to the present invention, the following general formula (5)

Embedded image R ₃ OOC—R ₁ —COOR ₄ (5) (wherein, R ₁ represents a divalent aliphatic group having 1 to 12 carbon atoms;
R ₃ and R ₄ represent a hydrogen atom, an aliphatic group or an aromatic group having 1 to 6 carbon atoms) or a diester (A) thereof, and the following general formula (6)

Embedded image HO—R ₂ —OH (6) (wherein, R ₂ represents a divalent aliphatic group having 1 to 12 carbon atoms)
An aliphatic diol (B) represented by the following general formula (7):

Embedded image HO—R ₅ —COOR ₆ (7) (wherein, R ₅ represents a divalent aliphatic group having 1 to 10 carbon atoms, and is a 3-hydroxyaliphatic carboxylic acid or a 4-hydroxyaliphatic) Divalent aliphatic groups derived from carboxylic acids are not included,
R ₆ represents hydrogen, an aliphatic group having 1 to 6 carbon atoms or an aromatic group) or an ester thereof, or the following general formula (8)

Embedded image (Wherein, R ₆ represents a divalent aliphatic group having 4 to 10 carbon atoms)
In the method for producing an aliphatic polyester having a number average molecular weight of 18,000 or more by subjecting a lactone (C) represented by the following formula to a polycondensation reaction in the presence of a catalyst, the molar ratio of the reaction components in the reaction raw materials is as follows: 0.0 ≦ (B) / (A) ≦ 1.05 (3) 0.02 ≦ (C) / (A + C) ≦ 0.30 (4) (wherein A is the aliphatic dicarboxylic acid or aliphatic dicarboxylic acid) The number of moles of the acid diester, B is the number of moles of the aliphatic diol, and C is the number of moles of the oxycarboxylic acid or its ester or the lactone). A method for producing a high molecular weight aliphatic polyester copolymer is provided.

The aliphatic dicarboxylic acid or aliphatic dicarboxylic acid diester (hereinafter referred to as A) used in the present invention includes those represented by the following general formula (5). During R ₃ OOC-R ₁ one COOR ₄ (5) the formula, R ₁ is a divalent aliphatic group, R ₃ and R ₄ represents a hydrogen atom, an aliphatic group, or an aromatic group. Examples of the divalent aliphatic group represented by R ₁ include a chain or cyclic alkylene group having 1 to 12, preferably 2 to 8 carbon atoms. Preferred alkylene _{groups, - (CH 2) 2 -} , - (C
H _{2) 4} - is a linear lower alkylene group having 2 to 6 carbon atoms such as. The divalent aliphatic group R ₁ can be a substituent inert to the reaction, for example, an alkoxy group or a keto group. Further, a hetero atom such as oxygen or sulfur can be contained in the molecule. When R ₃ and R ₄ are hydrogen atoms, they represent aliphatic dicarboxylic acids. Specific examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, and diglycolic acid. Examples of the aliphatic group represented by R ₃ and R ₄ include a linear or branched alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and a cycloalkyl group such as a cyclohexyl group. Alkyl groups can be mentioned. Examples of the aromatic group represented by R ₃ and R ₄ include a phenyl group and a benzyl group. R ₃ and R ₄ are preferably lower alkyl groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. Specific examples of the aliphatic dicarboxylic acid diester, for example, dimethyl succinate, diethyl succinate,
Dimethyl adipate, diethyl adipate, dimethyl pimerate, dimethyl azelate, dimethyl sebacate, diethyl sebacate, dimethyl decanedicarboxylate, dimethyl diglycolate, dimethyl ketohimenate, dimethyl malonate, dimethyl methyl malonate, and the like. . These may be used alone or in combination of two or more.

The aliphatic diol (hereinafter referred to as B) used in the present invention includes those represented by the following general formula (6). During HO-R ₂ -OH (6) the formula, R ₂ represents a divalent aliphatic group. Examples of the divalent aliphatic group include a chain or cyclic alkylene group having 2 to 12, preferably 2 to 8 carbon atoms. Preferred alkylene _{groups, - (CH 2) 2 -} , - (CH 2) 4 - carbon atoms such as 2-6
Is a linear lower alkylene group. Further, the divalent aliphatic group R ₂ can have a substituent inert to the reaction, for example, an alkoxy group or a keto group. Further, a hetero atom such as oxygen or sulfur can be contained in the molecule.
Specific examples of the aliphatic diol include, for example, ethylene glycol, 1,3-propanediol, 1,3-butanediol, 2-methyl-propanediol, 1,4-
Butanediol, neopentyl glycol, pendamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, dodecamethylene glycol, 1,4-cyclohexanedimethanol, and the like can be used. These may be used alone or in combination of two or more. One more
A small amount of a trifunctional glycol such as 1,1-tris (hydroxymethyl) propane may be used in combination.

The oxycarboxylic acid and oxycarboxylic acid ester (hereinafter referred to as C) used in the present invention include those represented by the following general formula (7). During _{HO-R 5 -COOR 6 (7} ) the equation, _{R 5} represents a divalent aliphatic group. Examples of the divalent aliphatic group include a chain or cyclic alkylene group having 2 to 10, preferably 2 to 8 carbon atoms. Further, the divalent aliphatic group R ₅ may have a substituent inert to the reaction, for example, an alkoxy group or a keto group. Further, a hetero atom such as oxygen or sulfur can be contained in the molecule. However, a divalent aliphatic group derived from a 3-hydroxy aliphatic carboxylic acid or a 4-hydroxy aliphatic carboxylic acid is not included. R ₆ is hydrogen, an aliphatic group or an aromatic group, and examples of the aliphatic group include a linear or branched lower alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and a cyclohexyl group. Examples of the cycloalkyl group having 5 to 12 carbon atoms and the aromatic group include a phenyl group and a benzyl group. Specific examples of the oxycarboxylic acid ester and the oxycarboxylic acid include, for example, methyl glycolate, ethyl glycolate, L-methyl lactate, L-ethyl lactate, D-methyl lactate, D-ethyl lactate, D, L-lactic acid Methyl, D, L
-Ethyl lactate, hydroxypivalic acid, hydroxycaproic acid, hydroxyhexanoic acid and the like.

The lactone (C) used in the present invention includes:
Examples represented by the following general formula (8) can be given.

Embedded image In the above formula, R ₆ represents a divalent aliphatic group. Examples of the divalent aliphatic group include a linear or branched alkylene group having 4 to 10, preferably 4 to 8 carbon atoms. Further, the divalent aliphatic group R ₆ may have a substituent inert to the reaction, for example, an alkoxy group or a keto group. Further, a hetero atom such as oxygen or sulfur can be contained in the molecule. However, the lactone does not include a lactone derived from 3-hydroxycarboxylic acid and a lactone derived from 4-hydroxycarboxylic acid. Specific examples of the lactone include, for example, γ-valerolactone, δ-valerolactone, ε-caprolactone, glycolide, L-lactide,
D-lactide, 1,3-dioxolan-4-one, 1,
4-dioxan-3-one, 1,5-dioxepane-2
-On and the like.

The catalyst used for producing the polymer of the present invention includes alkali metals such as lithium and potassium, alkaline earth metals such as magnesium, calcium and barium, typical metals such as tin, antimony and germanium, lead, zinc, and the like. Transition metals such as cadmium, manganese, cobalt, nickel, zirconium, titanium and iron, bismuth, niobium, lanthanum, samarium, europium,
Erbium, various compounds of lanthanoid metals such as ytterbium, for example, carboxylate, carbonate, borate,
Oxides, hydroxides, hydrogen compounds, alcoholates, acetylacetonate chelates and the like can be mentioned. Further, a nitrogen-containing basic compound, boric acid, a borate ester, or the like is also used.

As the alkali metal compound, specifically, sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium hydrogen carbonate, lithium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium acetate,
Potassium acetate, lithium acetate, sodium stearate, lithium stearate, sodium borohydride,
Examples include sodium borohydride, lithium benzoate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, lithium dihydrogen phosphate and the like.

Further, as the alkaline earth metal compound,
Specifically, calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, acetic acid Examples include calcium, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate.

Specific examples of the typical metal compound include dibutyltin oxide, dibutyltin dilaurate, antimony trioxide, germanium oxide, bismuth carbonate, and bismuth acetate.

Specific examples of the transition metal compound include lead acetate, zinc acetate, zinc acetylacetonate, cadmium acetate, manganese acetate, manganese acetylacetonate, cobalt acetate, cobalt acetylacetonate, nickel acetate, nickel acetylacetate. Examples include nitrate, zirconium acetate, zirconium acetylacetonate, titanium acetate, tetrabutoxytitanate, tetraisopropoxytitanate, titanium oxyacetylacetonate, iron acetate, iron acetylacetonate, and niobium acetate.

Examples of the rare earth compound include lanthanum acetate, samarium acetate, europium acetate, erbium acetate, ytterbium acetate and the like.

Specific examples of the nitrogen-containing basic compound include those derived from aliphatic amines and aromatic amines such as tetraethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide and trimethylbenzylammonium hydroxide. Organic ammonium hydroxides; tertiary amines such as trimethylamine, triethylamine, dimethylbenzylamine and triphenylamine; R ₂
Secondary amines represented by NH (where R is an alkyl group such as methyl and ethyl, and aryl groups such as phenyl and toluyl); and primary amines represented by RNH ₂ (where R is the same as described above) A basic compound such as ammonia, tetramethylammonium borohydride, tetrabutylammonium borohydride, tetrabutylammonium tetraphenylborate, and tetramethylammonium tetraphenylborate. Of these, tetraalkylammonium hydroxides are particularly preferred. Specific examples of the borate esters include trimethyl borate, trihexyl borate, triheptyl borate, triphenyl borate, and tolyl borate.
And trinaphthyl borate.

These catalysts may be used alone or in combination of two or more. The amount of the catalyst is 10 ^-7 to 10 ^-3 mol, preferably 10 ^{-6 to} 5 × 10 5 mol per mol of the aliphatic dicarboxylic acid or diester used as a raw material.
Preferably, it is used in an amount of ^-4 mol. If the amount of the catalyst is less than this range, the reaction does not proceed well and the reaction takes a long time. On the other hand, if it exceeds this range, it causes thermal decomposition, crosslinking, coloring, etc. of the polymer during polymerization,
Further, it is not preferable because it causes thermal decomposition and the like in the molding process of the polymer.

An aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid diester (A), an aliphatic diol (B), and an oxycarboxylic acid, an oxycarboxylic acid ester or a lactone (C) are subjected to a polycondensation reaction in the presence of a catalyst. In this case, it is necessary to select the proportions of these components A, B, and C so as to satisfy the following conditional expression. 1.0 ≦ (B) / (A) ≦ 1.05 (3) 0.02 ≦ (C) / (A + C) ≦ 0.30 (4) In these formulas, A is an aliphatic dicarboxylic acid or an aliphatic The number of moles of dicarboxylic acid diester used, B indicates the number of moles of aliphatic diol used, and C indicates the number of moles of oxycarboxylic acid, oxycarboxylic acid ester or lactone used. The number m of moles of the aliphatic dicarboxylic acid or aliphatic dicarboxylic acid diester used per mole of oxycarboxylic acid, oxycarboxylic acid ester or lactone is represented by the formula (4).
Can be obtained by That is, in equation (4),
If C = 1, the following equation can be obtained. 0.02 ≦ 1 / m + 1 ≦ 0.30 (9) From this inequality, the value of m is 2.3 ≦ m ≦ 49. When the amount is larger than the range of the aliphatic dicarboxylic acid or aliphatic dicarboxylic acid diester (A), the resulting polymer becomes hard materials inflexible will have high crystallinity, still in terms more biodegradable Will be inadequate. If the amount is less than the above range, the obtained polymer will have a low melting point, and furthermore, the crystallinity will be extremely reduced, and the physical properties will be reduced.

When an aliphatic dicarboxylic acid or an aliphatic dicarboxylic acid diester is subjected to a polycondensation reaction with an aliphatic diol and an oxycarboxylic acid, an oxycarboxylic acid ester or a lactone according to the present invention, the temperature is 80 ° C. in the initial stage of the reaction.
At a reaction temperature of 0.5 to 5 ° C, preferably 100 to 200 ° C, more preferably 120 to 180 ° C.
The reaction is carried out at normal pressure under a nitrogen atmosphere for a period of time, preferably 1 to 4 hours, and then the reaction is carried out by increasing the reaction temperature while reducing the pressure of the reaction system, and finally 180 ° C to 270 ° C, preferably 190 ° C It is preferable to carry out the reaction at a reaction temperature of 240 ° C. at a reduced pressure of 3 Torr or less, preferably at 1 Torr or less for 3 to 6 hours.

When the polymer of the present invention is produced, it is preferable to use an aliphatic dicarboxylic acid diester as a raw material, whereby the polycondensation reaction can proceed smoothly. In the case of this aliphatic dicarboxylic acid diester, an aliphatic dicarboxylic acid or an aliphatic carboxylic acid may be contained as an impurity, but the presence of such an impurity is not preferable because the molecular weight of the obtained polymer is reduced. Such impurities should be kept at 0.1 mol% or less, preferably 0.01 mol% or less, based on the aliphatic dicarboxylic acid diester. The molecular weight of the polymer of the present invention is 18,000 or more in number average molecular weight.
It is in the range of 8,000 to 80,000. Further, the melting point of the polymer of the present invention is usually as high as 80 ° C. or more, and the difference between the melting point and the decomposition temperature is as high as 100 ° C. or more. In the polymer of the present invention, particularly, R ₁ in the general formula (1) is (CH ₂ )
₂ , and those in which R ₂ is (CH ₂ ) ₄ have a high melting point and high crystallinity. In addition, the number average molecular weight referred to in this specification is a number average molecular weight in terms of polystyrene obtained by gel permeation chromatography (GPC).

[0026]

Next, the present invention will be described specifically with reference to examples. Various physical property values of the aliphatic polyester in the examples were determined by measuring according to 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 point and the glass transition point were determined by a differential scanning calorimeter (DSC). Thermogravimetric analyzer (T
The thermal decomposition temperature was determined according to G). The biodegradability of the aliphatic polyester obtained in the examples was measured as described below. (Evaluation of biodegradability) In the present invention, two types of biodegradability tests were used: a method by embedding in soil and a method by activated sludge. The test method is described below. 1. Soil embedding test 1) Test method: A polymer press sheet embedding test was performed for 30 days using a commercially available compost soil in a thermo-hygrostat. The decomposition rate was indicated by the weight loss rate. 2) Test conditions: (1) Soil: commercially available compost (2) Sample form: 40 × 40 × 0.15 mm press sheet (3) Test temperature: 30 ° C. (4) Test period: 30 days Test with activated sludge 1) Test method: Kanho No. 5, No. 615 and 49
The measurement was carried out with reference to a measurement method in a test for the degree of decomposition of a chemical substance by a microorganism specified in Basic Bureau No. 392. 2) Test conditions: (1) Test device: Oxygen consumption measuring device in closed system (courometer made by Okura Electric) (2) Activated sludge: Activated sludge of municipal sewage treatment plant (3) Sample form: powder (4) Test concentration: Sample 100ppm (charged amount 30mg) Sludge 30ppm (charged amount 9mg) (5) Test temperature: 25 ± 1 ° C (6) Test period: 4 weeks 3) Degradation calculation method (calculated from oxygen consumption) BOD: Biochemical oxygen demand (measured value) of test substance (m
g) B: Oxygen consumption (measured value) of basic culture solution (mg) TOD: theoretical oxygen demand (theoretical value) (mg)

EXAMPLE 1 43.84 g of dimethyl succinate, 27.49 g of 1,4-butanediol, and 2.7.7 g of methyl glycolate were placed in a 200 ml glass four-necked flask equipped with a stirring rod.
0 g and 26 mg of zinc acetylacetonate as a catalyst were charged, and the reaction was started at 180 ° C. under a nitrogen atmosphere. 1.
After 0 hour, the pressure was reduced while gradually increasing the reaction temperature. After 3.0 hours, the reaction temperature was 210 ° C. and the degree of vacuum was 0.5.
After reaching Torr, the reaction was further performed for 4.0 hours. The obtained polymer had Mn: 42,800 and Mw:
It had a molecular weight and molecular weight distribution of 98,400, Mw / Mn: 2.4, and had thermal properties of a melting point of 111 ° C and a thermal decomposition temperature of 315 ° C. As a result of structural analysis by ¹³ C-NMR of the obtained polymer, the absorption derived from carbon of carbonyl of succinic acid ester bond and 170 ppm were found at 172 ppm.
In addition, absorption derived from the carbon of the carbonyl of the ester bond of glycolic acid was observed. From the ¹ H-NMR, the content of the glycolic acid ester in the polymer was 9 mol
% Coincided with the charged composition ratio. 0.15x20x100m
A polymer dumbbell of m was prepared, and its mechanical strength was measured. As a result, it was found that the elastic modulus was 42 MPa and the elongation was 260%. As a result of the biodegradability test, the weight reduction rate of the press sheet was 27% in the soil embedding method. In the activated sludge method, the degree of decomposition was 50%.

Example 2 43.84 g of dimethyl succinate, 27.49 g of 1,4-butanediol and 1.04 g of DL-methyl lactate were placed in a 200 ml glass four-necked flask equipped with a stirring rod.
g) A reaction was carried out in the same manner as in Example 1 except that 20 mg of zinc acetate dihydrate was charged as a catalyst to obtain a target polymer. The obtained polymer had Mn: 32,400 and Mw:
It had a molecular weight and molecular weight distribution of 77,800, Mw / Mn: 2.4, and had thermal properties of a melting point of 112 ° C and a thermal decomposition temperature of 311 ° C. As a result of structural analysis by ¹³ C-NMR of the obtained polymer, absorption derived from carbon of carbonyl of succinic acid ester bond was observed at 172 ppm. From ¹ H-NMR, the absorption derived from hydrogen of the methyl group of DL-lactic acid was observed at 1.5 ppm, and the absorption derived from hydrogen of methine was observed at 5.1 ppm. D in the polymer
The content of L-lactic acid ester was 3 mol%, which almost coincided with the charged composition. A polymer dumbbell having a size of 0.15 × 20 × 100 mm was prepared, and its mechanical strength was measured. As a result, it was found that the elastic modulus was 50 MPa and the elongation was 210%. As a result of the biodegradability test, the weight reduction rate of the press sheet was 18% in the soil embedding method. In the activated sludge method, the degree of decomposition was 41%.

Example 3 A dimethyl succinate (43.84 g), 27.49 g of 1,4-butanediol, and ε-caprolactone 9.1 were placed in a 200 ml glass four-necked flask equipped with a stirring rod.
3 g and 10 mg of tetrabutyl titanate as a catalyst were charged, and the reaction was started at 170 ° C. under a nitrogen atmosphere. 1.0
After the elapse of time, the pressure was started while gradually increasing the reaction temperature, and after 3.5 hours, the reaction temperature was 200 ° C. and the degree of vacuum was 0.5 T.
After reaching orr, the reaction was further performed for 3.5 hours.
The obtained polymer had Mn: 35,400 and Mw: 8
It had a molecular weight and molecular weight distribution of 4,900, Mw / Mn: 2.4, and had thermal properties of a melting point of 98 ° C and a thermal decomposition temperature of 322 ° C. As a result of ¹³ C-NMR structural analysis of the obtained polymer, absorption derived from carbon of ester bond carbonyl was observed at 172 ppm. Also, ¹ H-NM
From R, the absorption derived from hydrogen of methylene at the α-position of ε-caprolactone was observed at around 2.3 ppm, and the composition ratio of ε-caprolactone in the polymer was 20 mol%, which almost coincided with the charged composition. A polymer dumbbell of 0.15x20x100mm was created and its mechanical strength was measured.
The elastic modulus was 32 MPa and the elongation was 340%, and the film was moldable and tough. As a result of the biodegradability test, the weight reduction rate of the pressed sheet was 36
%Met. In the activated sludge method, the degree of decomposition was 68%.

Example 4 Succinic acid dimethyl ester 29 was placed in a 1-liter glass four-neck separable flask equipped with a stirring rod of a helical ribbon.
0.28 g, 167.20 g of 1,4-butanediol,
27.86 g of glycolide and 80 mg of zirconium acetylacetonate as a catalyst were charged under a nitrogen atmosphere.
The reaction was started at 0 ° C. After 1.5 hours, the pressure was reduced while gradually increasing the reaction temperature. After 3.5 hours, the reaction temperature reached 210 ° C. and the degree of vacuum was 0.5 Torr, and then the reaction was continued for 4 hours. The resulting polymer has Mn:
34,500, Mw: 86,200, Mw / Mn: 2.
It had a molecular weight and molecular weight distribution of 5, a melting point of 105 ° C and a thermal decomposition temperature of 316 ° C. As a result of ¹³ C-NMR structural analysis of the obtained polymer, absorption derived from carbonyl carbon of ester bond of succinic acid was observed at 172 ppm, and absorption derived from carbonyl carbon of ester bond of glycolide was observed at 170 ppm. . Also ¹
According to H-NMR, the content of glycolide in the polymer was 12
In mol%, it almost coincided with the charged composition. 0.15x20x
A 100-mm polymer dumbbell was prepared and its mechanical strength was measured. As a result, it was found that the elastic modulus was 34 MPa and the elongation was 280%. As a result of the biodegradability test, the weight reduction rate of the press sheet was 30% in the soil embedding method. In the activated sludge method, the degree of decomposition was 62%.

EXAMPLE 5 Succinic acid dimethyl ester 29 was placed in a 1-liter glass four-neck separable flask with a stirring rod of a helical ribbon.
0.28 g, 167.20 g of 1,4-butanediol,
25.94 g of lactide and 40 mg of titanium oxyacetylacetonate as a catalyst were charged under nitrogen atmosphere.
The reaction was started at 70 ° C. After 1.5 hours, the pressure was started while gradually increasing the reaction temperature. After 3.5 hours, the reaction temperature reached 210 ° C. and the degree of vacuum reached 0.5 Torr.
The reaction was further performed for 4 hours. The polymer obtained is M
n: 33,000, Mw: 82,500, Mw / Mn:
Having a molecular weight and molecular weight distribution of 2.5, melting point 107 ° C.,
It had a thermal property of a thermal decomposition temperature of 315 ° C. As a result of structural analysis of the obtained polymer by ¹³ C-NMR, 172 pp
In m, absorption derived from the carbon of the carbonyl of the ester bond of succinic acid was observed. Also, the absorption derived from hydrogen of the methyl group of lactide was 1.5 ppm from ¹ H-NMR,
Absorption derived from hydrogen of methine was observed at 5.1 ppm. The composition ratio of lactide in the polymer was 9 mol%, which almost coincided with the charged composition ratio. 0.15 × 20 × 10
When a polymer dumbbell of 0 mm was prepared and the mechanical strength was measured, the elastic modulus was 33 MPa and the median was 280%.
The film was moldable, flexible and tough.
As a result of a biodegradability test, the weight reduction rate of the press sheet was 28% in the soil embedding method. In the activated sludge method, the degree of decomposition was 63%.

COMPARATIVE EXAMPLE 1 A dimethyl succinate (43.84 g) and 1,4-butanediol (28.39 g) were charged into a 200-ml glass four-necked flask equipped with a stirring rod and a polymerization reaction was carried out in the same manner as in Example 1. Was. The obtained polymer had Mn: 3
6,000, Mw: 82,800, Mw / Mn: 2.3
And a thermal property of a melting point of 118 ° C and a thermal decomposition temperature of 315 ° C. 0.15x20x1
A polymer dumbbell of 00 mm was prepared and measured for mechanical strength. As a result, it was found that the elastic modulus was 55 MPa and the elongation was 150%. However, as a result of the biodegradability test, the weight reduction rate of the pressed sheet was 11% in the soil embedding method, but the degradation degree was 3% in the activated sludge method, and the biodegradability was poor.

[0033]

The novel high-molecular-weight aliphatic polyester obtained by the present invention can be formed into films and fibers, has practical properties, and has an oxycarboxylic acid ester component in the polymer main chain. It has excellent biodegradability. Therefore, it has a wide range of applications such as films, fibers, sheets, bottles and the like.
This high molecular weight aliphatic polyester can be easily produced by reacting an aliphatic dicarboxylic acid or a diester thereof, an aliphatic diol, and an oxycarboxylic acid, an oxycarboxylic acid ester or a lactone at a specific ratio.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ikuo Takahashi 2-8-11 Nishi-Shimbashi, Minato-ku, Tokyo 7th Oriental Maritime Building 8th Floor Project Team for CO2 Fixation (72) ) Inventor Kenji Kawamoto 2-8-11 Nishi-Shimbashi, Minato-ku, Tokyo 7th Oriental Maritime Building 8th Floor Research Institute for Innovative Technology for the Earth, CO2 Fixation Project Room (72) Inventor Akio Matsuda Higashi Tsukuba, Ibaraki Prefecture 1-1, Institute of Industrial Science and Technology, National Institute of Materials Science (72) Inventor Takashi Masuda 1-1-1, Higashi, Tsukuba, Ibaraki Pref. Yoshihiko Funaoka (56) References JP-A-7-53685 (JP, A) JP-A-7-53899 (JP, ) Patent Akira 52-56193 (JP, A) JP flat 4-292619 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) C08G 63/60

Claims (4)

(57) [Claims] [Claim 1] (OC-R ₁ -COO-R ₂ -O) _p (1) wherein R ₁ is a divalent aliphatic group having 1 to 12 carbon atoms, R ₂ represents a divalent aliphatic group having 2 to 12 carbon atoms, p represents a mole fraction of the ester portion represented by the general formula (1) contained in the polyester copolymer), and (OC-R ₃ -O) _q (2) (wherein R ₃ is a divalent aliphatic group having 1 to 10 carbon atoms, and a 3-hydroxyaliphatic carboxylic acid is represented by the general formula (2)). Divalent aliphatic groups derived from acids or 4-hydroxy aliphatic carboxylic acids are not included,
q represents a mole fraction of the ester portion represented by the general formula (2) contained in the polyester copolymer), and the value of q is 0.02 to 0.3.
A biodegradable high molecular weight aliphatic polyester copolymer having a number average molecular weight of 18,000 or more in the range of 0. 2. R ₁ is (CH ₂ ) ₂ and R ₂ is (C
H ₂₎ biodegradable according to claim 1, characterized in that the alkylene group represented by ₄ high molecular weight aliphatic polyester copolymer. 3. A compound represented by the following general formula (5): R ₃ OOC—R ₁ —COOR ₄ (5) (wherein, R ₁ represents a divalent aliphatic group having 1 to 12 carbon atoms;
R ₃ and R ₄ represent a hydrogen atom, an aliphatic group or an aromatic group having 1 to 6 carbon atoms) or a diester (A) thereof, and the following general formula (6): _{HO-R 2 -OH (6)} ( wherein, _{R 2} is a divalent aliphatic group having 1 to 12 carbon atoms)
And an aliphatic diol (B) represented by the following formula (7): HO—R ₅ —COOR ₆ (7) (wherein, R ₅ is a divalent aliphatic having 1 to 10 carbon atoms) But does not include divalent aliphatic groups derived from 3-hydroxyaliphatic carboxylic acids or 4-hydroxyaliphatic carboxylic acids,
R ₆ represents hydrogen, an aliphatic group having 1 to 6 carbon atoms or an aromatic group) or an ester thereof, or the following general formula (8): (Wherein, R ₆ represents a divalent aliphatic group having 4 to 10 carbon atoms)
In the method for producing an aliphatic polyester having a number average molecular weight of 18,000 or more by subjecting a lactone (C) represented by the following formula to a polycondensation reaction in the presence of a catalyst, the molar ratio of the reaction components in the reaction raw materials is as follows: 0.0 ≦ (B) / (A) ≦ 1.05 (3) 0.02 ≦ (C) / (A + C) ≦ 0.30 (4) (wherein A is the aliphatic dicarboxylic acid or aliphatic dicarboxylic acid) The molar number of the acid diester, B represents the molar number of the aliphatic diol, and C represents the molar number of the oxycarboxylic acid or its ester or the lactone). A method for producing a degradable high molecular weight aliphatic polyester copolymer. 4. The method according to claim 1, wherein the content of the aliphatic dicarboxylic acid and the aliphatic carboxylic acid contained as impurities in the aliphatic dicarboxylic acid diester is maintained at 0.1 mol% or less based on the aliphatic dicarboxylic acid diester. A method for producing the biodegradable high molecular weight aliphatic polyester copolymer according to claim 3.