JPH0827269A - Biodegradable poly(ester-amide) and its production - Google Patents

Abstract

PURPOSE:To obtain the subject polymer excellent in both mechanical strength and biodegradability, useful for packaging and medical uses and for fishnets and fishlines,etc., by condensation reaction between an amino group-terminated aliphatic polyester and dicarboxylic acid. CONSTITUTION:This biodegradable poly(ester-amide) >=10000 in number-average molecular weight is obtained by polycondensation between (A) a prepolymer, an aliphatic polyester having amino group, pref. terminal groups of formula I (R is a divalent hydrocarbon) on both ends and (B) a dicarboxylic acid and/or derivative therefrom. In this polymer, aliphatic polyester blocks each composed of consecutive three or more polyester constituent units are regularly linked to one another via amide linkages. The prepolymer as the component A can be prepared by reaction of a nitro group-contg. carboxylic acid of formula II (X is OH, an alkoxyl, etc.) with a hydroxyl-terminated aliphatic polyester to synthesize an aliphatic polyester having terminal group of formula III, which is then hydrogenated.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to biodegradable poly (ester-amides) and processes for their preparation, and also to aliphatic polyesters containing terminal amino groups suitable for use in their preparation and processes for their preparation. .

[0002]

2. Description of the Related Art In recent years, biodegradable polymers that are decomposed by microorganisms have been attracting attention as polymers that are decomposed in the natural environment. Examples of such a polymer include poly (3-hydroxybutyrate) described in JP-A-52-87169 and JP-A-56-117793, and JP-A-57.
-150393 and JP-A-64-69622, poly (3-hydroxybutyrate-co-3-hydroxyvalerate), JP-A-64-48821 and JP-A-2-2346.
Poly (3-hydroxybutyrate) described in No. 83
-co-4-hydroxybutyrate) and other polyesters produced by microorganisms, or polypropiolactone, poly (ε-
Chemically synthesized aliphatic polyesters such as caprolactone), polyglycolic acid, polylactic acid, and polypivalolactone are known. Also, Macromolecules, Vol.25, 3309-3312
(1992) describes a method for producing a random copolymer of poly (ester-amide) by copolymerizing ε-caprolactam and ε-caprolactone, Journal of Applied.
Polymer Science, Vol.24, 1701-1711 (1979) describes that polycaprolactone and polyamide, which are biodegradable synthetic aliphatic polyesters, are heated to form poly (ester-amide) by an amide-transesterification reaction between them. It is described that a copolymer is produced, and that this method results in a random block copolymer, and finally a random copolymer.

However, the above-mentioned conventional microorganism-produced polyester and synthetic aliphatic polyester are inferior to general-purpose polymers such as nylon and polyethylene terephthalate in mechanical properties such as tensile strength and elongation. Therefore, it is difficult to use it in a field requiring strength such as fishing nets and fishing lines. Since these materials pose a particular problem as environmental pollution by plastics, biodegradable plastics having excellent strength are desired.

Further, in the above-mentioned known poly (ester-amide) random copolymer, the biodegradability is remarkably lowered with the increase of amide bonds, so that a poly (ester-amide) having strength and biodegradability is obtained. Has not been done. Moreover, the ester-amide exchange reaction requires a high temperature of 270 ° C., so that it can be applied only to thermally stable polyesters.

[0005]

As described above, no biodegradable polymer excellent in mechanical strength has been found so far. Therefore, an object of the present invention is to provide a polymer having both excellent mechanical properties and biodegradability, and a method for producing the same. Moreover, it aims at providing the prepolymer suitable for using for the manufacture, and its manufacturing method.

[0006]

The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, have obtained poly (ester) obtained by condensation of an aliphatic polyester having an amino group at the terminal and a dicarboxylic acid. -Amide) has been found to have improved mechanical strength while retaining the biodegradability of aliphatic polyesters, leading to the present invention.

Further, the inventors of the present invention react a polyester having a hydroxyl group at the terminal with a nitro group-containing carboxylic acid and / or a derivative thereof to introduce a nitro group at the terminal of the polyester, and then hydrogenate the nitro group. It was also found that the hydroxyl group terminal of the polyester can be efficiently converted to the amino group terminal by the method, and that the polyester having amino groups introduced at both terminals in this way is suitable for the production of the biodegradable poly (ester-amide). .

That is, the present invention comprises three or more continuous polyester constitutional units obtained by polycondensing an aliphatic polyester prepolymer having amino groups introduced at both ends and a dicarboxylic acid and / or a derivative thereof. A gist is a biodegradable poly (ester-amide) having a number average molecular weight of 10,000 or more, in which aliphatic polyester blocks containing the same are regularly linked through amide bonds. The above-mentioned prepolymer is preferably a compound represented by the general formula (I) at both ends.

[0009]

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(Wherein R is a divalent hydrocarbon group) is an aliphatic polyester containing a terminal group.

Further, a prepolymer in which amino groups are introduced at both ends of an aliphatic polyester, a dicarboxylic acid and / or
Alternatively, the present invention also relates to a method for producing the above biodegradable poly (ester-amide), which comprises polycondensing a derivative thereof to obtain poly (ester-amide).

In the above-mentioned production method, the prepolymer is a polyester having amino groups at the ends, which is obtained by reacting a polyester having hydroxyl groups at both ends with a nitro group-containing carboxylic acid and / or a derivative thereof and then hydrogenating. Preferably. Furthermore, the present invention provides the compound of general formula (I)

[0013]

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The present invention also relates to an amino-terminated aliphatic polyester containing an end group represented by R (wherein R is a divalent hydrocarbon group) and containing three or more polyester constitutional units. This amino-terminated aliphatic polyester has the same general formula (II) as the aliphatic polyester having a hydroxyl group at the terminal.

[0015]

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(Wherein, X is a hydroxyl group, an alkoxyl group or a halogen atom, and R is a divalent hydrocarbon group) and reacted with a nitro group-containing carboxylic acid and / or a derivative thereof to give a compound of the general formula (I)

[0017]

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(However, R is a divalent hydrocarbon group.)
It can be produced by synthesizing an aliphatic polyester having a terminal group represented by and then hydrogenating it. The present invention will be described in detail below.

The poly (ester-amide) of the present invention has 3
It is a polymer in which the aliphatic polyester moieties containing the above polyester constitutional units are regularly bonded via amide bonds. Since this polymer regularly contains a biodegradable aliphatic polyester moiety in a fixed length and has an amide bond, it has both biodegradability and mechanical strength. The poly (ester-amide) can control its mechanical strength and biodegradability by the molecular weight and composition of the polyester moiety.

The poly (ester-amide) of the present invention can be produced by polycondensing an aliphatic polyester (prepolymer) having amino groups at both ends with a dicarboxylic acid so as to have a high molecular weight. The manufacturing method will be described below. An example of the terminal amino group-containing aliphatic polyester is an aliphatic polyester having a terminal group represented by the following general formula (I).

[0021]

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In the above formula, R is a divalent hydrocarbon group,
For example, it is a divalent aromatic group such as a phenylene group or a naphthylene group, or a divalent aliphatic hydrocarbon group. As a preferred method for producing the terminal amino group-containing aliphatic polyester, a terminal hydroxyl group-containing aliphatic polyester is reacted with a nitro group-containing carboxylic acid and / or a derivative thereof to synthesize a terminal nitro group-containing polyester. Then
Next, there is a method of reducing the nitro group.

The aliphatic polyester having a hydroxyl group at the terminal used in this method has an average number of terminal hydroxyl groups per molecular chain of 1.3 to 4, and particularly, the number of hydroxyl groups is 1.9.
Polyesters from 1 to 2.3 are preferred. The number of hydroxyl groups is 1.
When it is less than 3, it is difficult to obtain a high molecular weight and sufficient mechanical properties cannot be obtained when the terminal of the polyester is made an amino group and then linked via an amide bond. Further, when the number of hydroxyl groups is 4 or more, a large number of network structures are formed in the subsequent increase in the molecular weight, which makes melt molding difficult.

This aliphatic polyester contains 3 or more polyester structural units. 2 units
When it is below, the length of biodegradable polyester chain is too short, and the biodegradability of the polymer obtained by increasing the molecular weight is not sufficient. The number of structural units is preferably from 3 to 600, and when it exceeds 600, the number of amide bonds is reduced and poly (ester-amide) has a sufficient mechanical strength when it is converted into a poly (ester-amide) having a desired molecular weight. Is difficult to obtain.

Such terminal hydroxyl group-containing aliphatic polyester can be obtained, for example, by ring-opening polymerization of ε-caprolactone with ethylene glycol or triethylene glycol as a catalyst, polycondensation of excess diol and dicarboxylic acid, or presence of diols. It can be synthesized by a method such as ring-opening polymerization of β-butyrolactone below, but the synthetic method is not particularly limited.

Specific examples of the terminal hydroxyl group-containing aliphatic polyester include poly (ε-caprolactone), poly (3-hydroxybutyrate), poly (propiolactone), poly (valerolactone) and poly having a hydroxyl group at the terminal. Examples include glycolide, polylactide, and random copolymers thereof. Examples of the aliphatic polyester obtained by polycondensation of excess diol and dicarboxylic acid include, for example, dicarboxylic acid containing at least one kind of oxalic acid, succinic acid and adipic acid, ethylene glycol, propylene glycol and butane. There is a polyester composed of a diol containing at least one kind of diol.

The terminal hydroxyl group-containing aliphatic polyester used in the present invention is particularly preferably a ring-opening polymerization of a lactone in the presence of a diol, which has a diol residue in the chain and hydroxyl groups at both ends. It is an aliphatic polyester. The thus-obtained polyester has a controlled molecular weight depending on the amount of diol added and has a narrow molecular weight distribution, so that a polyester having a desired uniform molecular weight can be obtained, which is advantageous for use in the present invention. For example, when β-butyrolactone is subjected to ring-opening polymerization in the presence of diols, a diol residue is bound in the chain of poly (3-hydroxybutyrate) (hereinafter abbreviated as PHB), and PHB having hydroxyl groups at both ends is formed. Is obtained. As the diols, ethylene glycol, propanediol, butanediol, neopentyl glycol and the like can be used. Ring-opening polymerization of β-butyrolactone in the presence of diols is specifically
It is carried out by reacting β-butyrolactone in the presence of a reaction product obtained by reacting an organozinc compound and a diol. The reaction is completed in 5 hours or less, particularly preferably 3 hours or less when carried out at a reaction temperature of 60 to 200 ° C. in a solvent-free or inert organic solvent. The modified PHB thus obtained preferably has a number average molecular weight of 600 to 50,000, particularly preferably 1,000 to 10,000. According to this method, a weight average molecular weight / number average molecular weight ratio (Mw / Mn ratio), which indicates the molecular weight dispersity of the polymerization product, is generally 1.2 or less, and a polymerization product having a uniform molecular weight is obtained. Polyester having a narrow molecular weight distribution, when used as a prepolymer in the synthesis of poly (ester-amide), improves the homogeneity of the physical properties and biodegradability of the obtained polymer, improves the physical properties and makes the whole uniform. It is very advantageous because it can be uniformly biodegradable.

Next, the terminal of the above hydroxyl-terminated polyester is nitrated. The nitro group-containing carboxylic acid or its derivative (acyl halide compound or ester compound) that can be used for terminal nitration is represented by the general formula

[0029]

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It is represented by In the formula, R is a divalent hydrocarbon group, the same as R described above, and X is a hydroxyl group, an alkoxyl group or a halogen atom. As the nitro group-containing carboxylic acid or its derivative, nitrobenzoic acid,
Aromatic nitrocarboxylic acids such as benzoyl nitrochloride, methyl nitrobenzoate, nitronaphthoic acid, naphthoyl nitrochloride, methyl nitronaphthoate, nitrophenylacetic acid, nitrophenylacetyl chloride and methyl nitrophenylacetate, and their acyl halide compounds and esters. Compound, or nitrobutanoic acid, nitrobutanoyl chloride,
Aliphatic nitrocarboxylic acids such as methyl nitrobutanoate,
Examples thereof include acyl halide compounds and ester compounds.

By reacting these nitro group-containing carboxylic acid or its derivative with the above hydroxyl group-terminated polyester in the presence of a catalyst, a polyester having a nitro group at the terminal represented by the following general formula (III) can be obtained. .

[0032]

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However, R is a divalent hydrocarbon group and is the same as R described above. The amount of the nitro group-containing carboxylic acid or its derivative is 0.5 to 10 in molar ratio with respect to the hydroxyl group amount of the above or the hydroxyl group-containing aliphatic polyester, and
To 5 are preferable. If the molar ratio is less than 0.5, the ratio of unreacted hydroxyl groups becomes large, and even if the molecular weight is increased, satisfactory mechanical strength cannot be obtained. On the other hand, if the amount is more than 10, it takes a lot of cost to remove and recover the unreacted nitro group-containing carboxylic acid or derivative, which is not economical.

When a nitro group-containing carboxylic acid or its ester compound is used in the nitration of the polyester terminal, a metal alkoxide such as titanium tetraisopropoxide or an oxide or salt of a metal such as titanium or tin is used as a catalyst. Used. Reaction temperature is 150-250
C., preferably 170 to 220.degree. Reaction temperature is 150 ℃
If it is lower, the reaction rate is remarkably reduced, which is not preferable. On the other hand, if the reaction temperature is 250 ° C. or higher, undesired side reactions such as decomposition of polyester will occur. Reaction time from 0.1
It is 10 hours, preferably 0.5 to 6 hours. When the reaction time is shorter than 0.1 hours, it is difficult to complete the reaction. Further, if the reaction time is 10 hours or more, undesired side reactions may occur together, and the reaction time is too long, which is not economical. Since this reaction is carried out while removing by-produced water or alcohol from the reaction system, it is preferable to carry out the reaction under reduced pressure. Furthermore, this reaction is generally performed without a solvent, but a solvent having a high boiling point which is inert to this reaction, such as diphenyl ether or nitrobenzene, can be used.

When a nitro group-containing acyl halide compound is used for nitration, pyridine is used as a catalyst,
Organic bases such as dimethylaniline, triethylamine, and tetramethylurea, and inorganic bases such as sodium hydroxide aqueous solution and potassium hydroxide aqueous solution are used. As the solvent in this reaction, an organic base that is liquid at the reaction temperature, such as pyridine, dimethylaniline, triethylamine, tetramethylurea, which is also a catalyst, can be used. Alternatively, a solvent in which the polyester and the acyl halide compound containing a nitro group are well dissolved and which is inert to the reaction can be used. Such solvents include dichloromethane, dichloroethane, chlorobenzene, halides such as dichlorobenzene, diethyl ether,
Ether compounds such as tetrahydrofuran, toluene,
There are aromatic compounds such as benzene. This reaction is carried out while gradually adding a solution of a nitro group-containing acyl halide compound to the polyester solution or a solution of a nitro group-containing acyl halide compound in order to suppress a temperature increase due to heat of reaction and side reactions. It is preferable to carry out while gradually adding the polyester solution. Reaction temperature is -20 ~
80 ° C, preferably -10 to 50 ° C. Reaction temperature is -20 ℃
If it is lower, the reaction rate is remarkably reduced, which is not preferable. Further, when the reaction temperature is 80 ° C. or higher, undesired side reactions occur together. The reaction time is 0.1 to 100 hours, preferably
0.5 to 10 hours. When the reaction time is shorter than 0.1 hour, it is difficult to complete the reaction. Also, the reaction time
If it is more than 100 hours, undesired side reactions may occur, and the reaction time is too long, which is not economical.

In the nitration of the polyester terminal, for the convenience of operation, after completion of the synthesis of the hydroxyl group-terminated polyester, the polyester can be used as it is without removing it from the reaction system as described below. .

When the polyester synthesis is carried out without a solvent, or when the polyester is deposited even if the solvent is used, a solvent is added to the reaction system after completion of the polyester synthesis, and a catalyst and a nitro group-containing acyl halide compound are added. Is added and the reaction is carried out. The solvent that can be used is a solvent that dissolves the produced polyester well and is inert to the acyl halide compound and the hydroxyl group, and is, for example, a halide such as chloroform, dichloromethane, dichloroethane, chlorobenzene, dichlorobenzene, diethyl ether, tetrahydrofuran, etc. Ether compounds,
There are aromatic compounds such as toluene and benzene. Also,
When the polyester synthesis is performed using a solvent and the polyester is not precipitated, these solvents may not be added. In this case, the catalyst and the nitro group-containing acyl halide compound are directly added to carry out the reaction.

By reducing the terminal nitro group of the nitro group-terminated polyester obtained as described above, a polyester having a terminal group represented by the general formula (I) can be produced. For example, hydrogenation of a nitro group can be carried out by adding a catalyst for reducing a nitro group carrying a metal, a metal compound or a metal oxide to a solution of polyester and reducing with a hydrogen gas. Examples of the catalyst that can be used include palladium, platinum, rhodium, ruthenium and carbon supporting its oxide, alumina, silica and the like. As the solvent, alcohol compounds such as methanol, ethanol and butanol, ether compounds such as tetrahydrofuran, and aromatic compounds such as benzene can be used. The reaction temperature is 0 to 100 ° C, preferably
10 to 60 ° C. If it is lower than 0 ° C, the reaction rate is remarkably reduced, which is not preferable. Further, when the reaction temperature is 100 ° C. or higher, undesirable side reactions occur simultaneously. The reaction time is 0.1 to 100 hours, preferably 0.5 to 10 hours. Reaction time is 0.
It is difficult to complete the reaction when the time is shorter than 1 hour.
Further, if the reaction time is 100 hours or more, undesired side reactions may occur together and the reaction time is too long, which is not economical. The hydrogenation of the nitro group is not limited to the above method as long as it can convert the nitro group into an amino group without causing side reactions such as decomposition of polyester.

The polyester having amino groups at both ends, which is obtained by the method of introducing an amino group as described above, is reacted with a compound having a functional group capable of easily reacting with an amino group to form a polymer. , Can be made higher in molecular weight. In addition to the dicarboxylic acid and its acid halide used in the synthesis of poly (ester-amide) described below, methylene diphenyl diisocyanate,
Isocyanate compounds such as toluene diisocyanate and formaldehyde can be used.

The poly (ester-amide) of the present invention can be obtained by polycondensing an aliphatic polyester having amino groups at both ends with a dicarboxylic acid and / or its derivative.

Examples of the dicarboxylic acid include aliphatic carboxylic acids such as oxalic acid, succinic acid and adipic acid, and aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid. Examples of the acid derivative include ester and acyl halide.

The dicarboxylic acid and / or derivative thereof and the terminal amino group-containing polyester have a ratio of the number of carbonyl group moles of the dicarboxylic acid and / or derivative thereof to the amino group mole number of the terminal amino group-containing polyester of 0.8 to.
The reaction is carried out at a ratio of 1.2, preferably 0.9 to 1.1. If this molar ratio is less than 0.8 or exceeds 1.2, a high polymer cannot be obtained. The resulting poly (ester-amide) has a molecular weight of 10,000 or more, preferably 10,000 to 1,000,00.
It is 0.

When polycondensation is carried out using a dicarboxylic acid and / or its ester, it is preferred to carry out at a reaction temperature of 160 ° C. to 280 ° C. under reduced pressure without a solvent while removing by-produced water or alcohol. If the reaction temperature is lower than 160 ° C, the reaction becomes slow, and if it is higher than 280 ° C, side reactions such as decomposition of the polyester occur simultaneously, which is not preferable. The reaction time is 0.5 to 20 hours, preferably 1 to 10 hours. If it is less than 0.5 hours, the reaction is not completed and a high molecular weight product cannot be obtained.
If it exceeds 20 hours, unfavorable side reactions will occur and it is not economical.

When polycondensation is carried out using an acyl halide of a dicarboxylic acid, an organic base such as pyridine, dimethylaniline, triethylamine or tetramethylurea, or an inorganic base such as sodium hydroxide aqueous solution or potassium hydroxide aqueous solution is used as a catalyst. A base can be used. As the solvent, an organic base that is liquid at the reaction temperature, such as pyridine, dimethylaniline, triethylamine, tetramethylurea, which is also a catalyst, can be used. Or
As a solvent, a polyester and an acyl halide of a dicarboxylic acid are well dissolved, and as a compound inert to the reaction, a halide such as dichloromethane, dichloroethane, chlorobenzene and dichlorobenzene, an ether compound such as diethyl ether and tetrahydrofuran, toluene and benzene. Aromatic compounds such as may be used. This reaction is carried out while gradually adding the solution of the acyl halide compound to the solution of the amino group-terminated polyester in order to suppress the temperature rise due to the heat of reaction and the occurrence of side reactions. It is preferable to carry out the reaction while gradually adding the solution. The reaction temperature is -20 to 80 ° C, preferably -10 to 50 ° C. If the reaction temperature is lower than -20 ° C, the reaction rate is remarkably reduced, which is not preferable. Further, when the reaction temperature is 80 ° C. or higher, undesired side reactions occur together. The reaction time is 0.1 to 100 hours, preferably 0.5 to 10 hours. Reaction time
It is difficult to complete the reaction if the time is shorter than 0.1 hours. Further, if the reaction time is 100 hours or more, undesired side reactions may occur together and the reaction time is too long, which is not economical.

The poly (ester-amide) of the present invention can be molded into various shapes by known methods. As a molding method, for example, extrusion molding, injection molding or the like is used, and the shape of the obtained molded product has various shapes such as a pellet shape, a film shape, a sheet shape, a plate shape and a thread shape.

The poly (ester-amide) of the present invention has a regular biodegradable aliphatic polyester moiety, and since these are linked by an amide bond, they have biodegradability and mechanical properties. Is also excellent. In this polymer, its mechanical strength and biodegradability can be controlled by changing the molecular weight and composition of the polyester part, and the mechanical strength, which was a drawback of conventional biodegradable polymers, can be improved, A high-strength biodegradable polymer can be obtained. Therefore, the biodegradable polymer can be used for various applications that are expected to be used for biodegradable polymers, such as fishery materials, packaging films, containers, agricultural films, forestry materials, and medical materials. In particular, it is very advantageous for application to fishing nets, fishing lines, and other fishing materials in which environmental pollution in the ocean is a problem because of its high strength.

[0047]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 Nitration of Terminal Hydroxyl Group of Polyester Poly (3-hydroxybutyrate) having a hydroxyl group at the terminal
Was synthesized by the following procedure.

After purging a 100 ml three-necked flask equipped with a reflux condenser and a nitrogen introducing tube with a rotor with nitrogen, 20 ml of toluene and 1 ml of 1M-diethylzinc (toluene solution) were added.
(1.0 mmol) and 1,4-butanediol 0.44 ml (5.0
mmol) were sequentially added, and the mixture was heated with stirring at 100 ° C. for 1 hour.
Next, the reaction vessel was cooled to room temperature, and the R-form composition was β of 96%.
-Butylolactone (BL) and racemic BL were added with 10 ml of BL having 90% of R composition, and the mixture was heated and stirred again at 100 ° C for 2 hours. After completion of the reaction, the mixture was cooled to room temperature and the reaction solution was washed successively with a 1% hydrochloric acid aqueous solution and water. afterwards,
Toluene was removed under reduced pressure to obtain 10.7 g of polymer. When the number average molecular weight (Mn) was analyzed by gel permeation chromatography (hereinafter referred to as GPC), it was 2300, and the molecular weight distribution dispersity (weight average molecular weight / number average molecular weight, Mw / Mn) was 1.1. In addition, it was analyzed by proton NMR.

¹ H-NMR: δ ^ppm 1.10-1.37 (3 H, C H _3- ), 1.
_{66-1.74 (0.15H, -C H 2 C} H 2 -), 2.38-2.68 (2H, -C H 2 CO-), 4.05-4.13 (0.16H, -0C
_{H 2 C H 2 -) 4.13-4.24} [0.08H, HOC H (CH 3) -], 5.18-5.36 [1H, -C
H (CH ₃ )-] Assuming that this polyester has hydroxyl groups at both ends,
The peak derived from the terminal methine [HOC H (CH ₃ )-] (δ
^ppm 4.13-4.24) intensity and peak derived from methyl group (δ
The Mn of the polyester was calculated to be 2240 from the intensity of ^ppm 1.10-1.37) according to the equation (1), which was in good agreement with the Mn obtained by GPC.

Mn = [A (CH ₃ ) / 3] / A [HOCH (CH ₃ )-] × 2 × 86.09 +88 (A represents the peak area) Therefore, the obtained polyester has hydroxyl groups at both ends. It turns out that it is polyester.

Next, the hydroxyl group terminal of the polyester obtained above is nitrated. A 300 ml three-necked flask equipped with a thermometer, a dropping funnel and a cooling tube is equipped with a stir bar and polyester.
10 g, 50 ml of dichloromethane and 2.4 ml of pyridine were charged to dissolve the polyester. Next, the solution was cooled to 0 ° C.
10 ml of a dichloromethane solution in which 4.1 g of nitrobenzoyl chloride was dissolved was added dropwise with a dropping funnel over about 30 minutes. After the completion of the dropping, the mixture was further stirred at a reaction temperature of 0 ° C. for 2 hours. After that, the reaction solution was taken out, and then 5% sodium hydrogencarbonate aqueous solution, 2% hydrochloric acid aqueous solution and water were sequentially added.
Washed thoroughly. After washing, dichloromethane was removed from the reaction solution by an evaporator and dried under reduced pressure at 40 ° C., and 11.0 g of a viscous polymer was obtained. The Mn of this polymer was 2500 as analyzed by GPC. Moreover,
Since Mw / Mn is 1.1, which is the same as the value before the reaction, it can be seen that the polyester is not decomposed in this reaction.

When analyzed by proton NMR, it was found to be 5.25
A peak derived from methine [-OC H (CH ₃ )-] bound to the nitrophenyl carboxyl group was confirmed at -5.58 ppm,
4.13-Confirmed with polyester having hydroxyl groups at both ends
The peak derived from 4.24 ppm of methine [HOC H (CH ₃ )-] disappeared. Therefore, it was confirmed that the hydroxyl group terminal was completely reacted with the acyl chloride group of nitrobenzoyl chloride to obtain a polyester having a nitro group terminal.

Amination of terminal nitro group of polyester 10 g of polyester having a nitro group terminal, 5% -Pd / C 0.2
g was charged into a metal autoclave having an internal volume of 200 ml, and the inside of the system was replaced with argon. Then, thoroughly degassed and dried tetrahydrofuran (hereinafter referred to as THF) 50
ml was added under a stream of argon. Next, the system was replaced with hydrogen, and the mixture was stirred at 40 ° C. for 4 hours at an initial hydrogen pressure of 9 kg / cm ² .

After completion of the reaction, the content liquid was taken out, 5% -Pd / C was removed by suction filtration, THF was removed by a rotary evaporator, and vacuum drying was carried out at 40 ° C. until a constant weight was obtained. Got

When the obtained polymer was analyzed by GPC, Mn was 2500 and Mw / Mn was 1.1 and there was no change before and after the reaction. Therefore, in this reaction, side reactions such as decomposition of polyester did not occur. Recognize.

In addition, the amount of amino group was determined by Anal. Chem., Vol.
It was 0.85 mmol / g when quantified by non-aqueous titration using perchloric acid described in p.1977 (1956). Assuming the polymer has amino groups at both ends, its Mn is 2360, which is in good agreement with the GPC value. Therefore, it was revealed that all the nitro groups were converted into amino groups, and the intended amino group-terminated polyester was obtained.

5 g of the amino group-terminated polyester obtained by increasing the molecular weight of the amino group-terminated polyester was stirred with a stirrer,
A 200 ml three-necked flask equipped with a reflux condenser and a thermometer was charged, and after adding 50 ml of dichloromethane to dissolve it,
0.5 ml of pyridine was added. Then the solution is cooled to 0 ° C.,
With vigorous stirring, 10 ml of a dichloromethane solution in which 0.777 g of adipoyl chloride was dissolved was quickly added. A solid was obtained immediately after the dropping. After stirring for 30 minutes as it was, the content was filtered and further thoroughly washed with methanol. The obtained solid matter was dried under reduced pressure at 40 ° C. until a constant weight was obtained.

The solid obtained was an elastic, rubbery polymer. When the molecular weight of this polymer was measured by GPC using hexafluoroisopropanol as an eluent, Mn was 42000 and Mw / Mn was 3.1. Thus, higher molecular weight polymers were obtained from amino-terminated polyesters.

Mechanical Properties of Poly (ester-amide) A film was prepared from the obtained solution of the high molecular weight polymer in hexafluoroisopropanol by a solvent-cast method, and the mechanical properties of the film were measured by a tensile tester. The results are shown in Table 1. As is clear from Table 1, this polymer has sufficient tensile strength and elongation.

Example 2 Polycaprolactone diol
(Aldrich, Mw = 1250) was subjected to terminal nitration and amination in the same manner as in Example 1.

The terminal hydroxyl groups of polycaprolactone diol were quantified by the acetyl chloride method described in "Epoxy Resins", p.25, McGraw-Hill (1957). The amino group of the amino group-terminated polycaprolactone was quantified by the same method as in Example 1. As a result, the amount of hydroxyl groups in polycaprolactone diol and the amount of amino groups in amino group-terminated polycaprolactone were 1.6 mmol / g and 1.7 mmol / g, respectively, which were in good agreement. Therefore, it can be seen that polycaprolactone in which the terminal hydroxyl group was completely converted to an amino group was obtained.

The amino group-terminated polycaprolactone was polymerized with adipoyl chloride in the same manner as in Example 1. When the obtained polymer was analyzed by GPC, Mn
Was 25,000 and Mw / Mn was 2.8. A film was prepared from the obtained polymer in the same manner as in Example 1, and the mechanical properties were measured.

(Example 3) "Macromolecular Synthesis",
Vol.1, John Wiley (1977), p.17, using the same method as described in dimethyl adipate 10 g and ethylene glycol.
Poly (ethylene adipate) (molecular weight: 470) was synthesized from 4.5 g. Further, terminal nitration and amination were carried out in the same manner as in Example 1. When the hydroxyl groups and amino groups were quantified in the same manner as in Example 1 and Example 2, the amount of hydroxyl groups in poly (ethylene adipate) was 2.2 mmol /
The amount of amino groups in the aminated poly (ethylene adipate) was 2.3 mmol / g. Therefore, it can be seen that poly (ethylene adipate) in which the terminal hydroxyl group was completely converted to an amino group was obtained.

The amino group-terminated poly (ethylene adipate) was polymerized with adipoyl chloride in the same manner as in Example 1. When the obtained polymer was analyzed by GPC, Mn was 47,000 and Mw / Mn was 3.1. A film was prepared from the obtained polymer in the same manner as in Example 1, and the mechanical properties were measured. The measurement results of the mechanical properties of the poly (ester-amide) obtained in Examples 1 to 3 are shown in Table 1 below together with the mechanical properties of Comparative Examples.

[0066]

[Table 1]

Microbial Degradability of Poly (ester-amide) The microbial degradability of the above various poly (ester-amide) prepared by the solvent-cast method was evaluated by the following method.

0.2 g of soil collected in Hasaki Town, Kashima District, Ibaraki Prefecture
Was extracted with 5 ml of sterilized water, and 0.2 ml of the extract was added to 5 ml of the culture solution shown in Table 2 to give a microbial degradability evaluation solution.

Films of various poly (ester-amide) s (1 cm × 1 cm, weight = 4-6 mg) were immersed in this evaluation liquid, and shaken at 30 ° C. for 48 hours. Then, the film was taken out from the culture solution, dried sufficiently, and then weighed. The results are shown in Table 3.

[0070]

[Table 2]

[0071]

[Table 3]

The nitration of the terminal, which is carried out before the amination of the polyester terminal, may be carried out after the synthesis of the hydroxyl group-terminated polyester without removing the polyester from the reaction solution. This example will be specifically described in Reference Examples 1 and 2 below.

(Reference Example 1) Nitration of terminal hydroxyl group of polyester Poly (3-hydroxybutyrate) having hydroxyl group at the terminal
Was synthesized by the following procedure.

After purging a 100 ml three-necked flask equipped with a reflux condenser and a nitrogen introducing tube with a rotor with nitrogen, 20 ml of toluene and 1 ml of 1M-diethylzinc (toluene solution) were added.
(1.0 mmol) and 1,4-butanediol 0.44 ml (5.0
mmol) were sequentially added, and the mixture was heated with stirring at 100 ° C. for 1 hour.
Next, the reaction vessel is cooled to room temperature and β-butyrolactone is added.
(BL) 10 ml was added, and the mixture was again heated and stirred at 100 ° C. for 2 hours. After completion of the reaction, this solution was cooled to 0 ° C., 2.4 ml of pyridine was added with stirring, and then benzoyl nitrochloride 4.1
10 ml of a dichloromethane solution in which g was dissolved was added dropwise with a dropping funnel over about 30 minutes. After the completion of the dropping, the mixture was further stirred at a reaction temperature of 0 ° C. for 2 hours. After that, the reaction solution is taken out and 5
% Aqueous sodium hydrogen carbonate solution, 2% aqueous hydrochloric acid solution, and water, and the mixture was thoroughly washed in that order. After washing, dichloromethane was removed from the reaction solution by an evaporator and vacuum drying was carried out at 40 ° C., and 11.4 g of a viscous polymer was obtained. When the Mn of this polymer was analyzed by GPC, it was 2400.
The Mw / Mn was 1.1.

When analyzed by proton NMR, it was found to be 5.25
A peak derived from methine [-OC H (CH ₃ )-] bound to the nitrophenyl carboxyl group was confirmed at -5.58 ppm,
4.13-Confirmed with polyester having hydroxyl groups at both ends
No peak derived from 4.24 ppm of methine [HOC H (CH ₃ )-] was observed. Therefore, it was confirmed that the hydroxyl group terminal was completely reacted with the acyl chloride group of nitrobenzoyl chloride to obtain a polyester having a nitro group terminal.

Reference Example 2 Nitration of Terminal Hydroxyl Group of Polyester "Macromolecular Synthesis", Vol.1, John Wiley (19
77), p.17, and poly (ethylene adipate) was synthesized from 10 g of dimethyl adipate and 4.5 g of ethylene glycol by the same method as described in p.17. Next, 50 ml of dichloromethane
Was added to dissolve the polyester, and the solution was added to 0 ° C.
After cooling, and stirring, 3.0 ml of pyridine was added, and then 6.5 g of benzoyl nitrochloride was dissolved in a dichloromethane solution.
ml was added dropwise with a dropping funnel over about 30 minutes. After the dropping is completed,
The reaction was further stirred at 0 ° C. for 2 hours. After that, the reaction solution was taken out, 5% sodium hydrogen carbonate aqueous solution, and 2%
It was thoroughly washed successively with an aqueous hydrochloric acid solution and water. After washing
Dichloromethane was removed from the reaction solution with an evaporator, and
It was dried under reduced pressure at ℃.

When this polymer was analyzed by proton NMR, a peak derived from methylene [-OC H _2- ] bonded to a nitrophenylcarboxyl group was confirmed at 5.4 to 5.6 ppm, and confirmed with a polyester having hydroxyl groups at both ends. Was done
No peak derived from methylene [HOC H _2- ] at 4.0-4.2 ppm was observed. Therefore, it was confirmed that the hydroxyl group terminal was completely reacted with the acyl chloride group of nitrobenzoyl chloride to obtain a polyester having a nitro group terminal.

[0078]

As described above, according to the present invention,
It is possible to provide a poly (ester-amide) having excellent mechanical properties and biodegradability. This poly (ester-amide) has improved mechanical properties as compared to conventional biodegradable polymers, has practically sufficient strength, and retains biodegradability. Therefore, the use of the biodegradable polymer can be expanded. For example, it is useful for various uses such as packaging, medical use, agriculture, forestry, and fisheries. In addition, the conventional biodegradable polymer can be used in fishing applications such as fishing nets and fishing lines, which are difficult to apply due to insufficient strength.

If a polycondensation of amino group-terminated polyester and dicarboxylic acid is used as a method for producing this polymer, a high polymer can be easily obtained. Further, the amino group-terminated polyester used in this method can be efficiently produced by the method of nitrating the terminal of the hydroxyl group-terminated polyester and then aminating.

Claims (6)

[Claims] 1. An aliphatic polyester containing 3 or more continuous polyester constitutional units, which is obtained by polycondensing a prepolymer in which amino groups are introduced at both ends of an aliphatic polyester and a dicarboxylic acid and / or a derivative thereof. A biodegradable poly (ester-amide) having a number average molecular weight of 10,000 or more, in which blocks are regularly linked through amide bonds. 2. The prepolymer has the general formula (I): (Wherein R is a divalent hydrocarbon group), which is an aliphatic polyester containing an end group.
The biodegradable poly (ester-amide) described. 3. A poly (ester-amide) is obtained by polycondensing a prepolymer in which amino groups are introduced at both ends of an aliphatic polyester and a dicarboxylic acid and / or its derivative. 1. The method for producing a biodegradable poly (ester-amide) according to 1. 4. An aliphatic compound having amino groups at both ends, obtained by reacting a polyester having hydroxyl groups at both ends with a nitro group-containing carboxylic acid and / or a derivative thereof, and then hydrogenating the prepolymer. The method according to claim 2, which is polyester. 5. A compound represented by the general formula (I): (However, R is a divalent hydrocarbon group.) An amino-terminated aliphatic polyester containing a terminal group represented by 3 or more polyester structural units. 6. An aliphatic polyester having a hydroxyl group at a terminal and a compound represented by the general formula (II): (However, X is a hydroxyl group, an alkoxyl group or a halogen atom, and R is a divalent hydrocarbon group.) The nitro group-containing carboxylic acid and / or its derivative represented by the general formula (III) [Chemical 3] (However, R is a divalent hydrocarbon group.) After synthesizing an aliphatic polyester having an end group represented by the general formula (IV): (However, R is a divalent hydrocarbon group.) The aliphatic polyester which has the terminal group shown by these is synthesize | combined, The manufacturing method of the amino terminal aliphatic polyester of Claim 4 characterized by the above-mentioned.