JP2002293898A - High molecular weight aliphatic copolyester and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a biodegradable high molecular weight aliphatic copolyester to be formable into a film or a sheet having mechanical properties similar to those of polyethylene. SOLUTION: This copolyester has a molecular chain comprising a repeating unit (P) expressed by -CO-R<1> -COO-R<2> -O- (R<1> represents 1-12C divalent aliphatic group; R represents 2-12C divalent aliphatic group) and -CO-R<3> -O- (R<3> represents 1-10C divalent aliphatic group), wherein at least one divalent aliphatic group of R<1> , R<2> and R<3> comprises 0.01 to 50 mol% of branched divalent aliphatic group to the total 100 mol% of R<1> , R<2> and R<3> divalent aliphatic groups.

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, and more particularly, to a biodegradable molded article such as a sheet or film having sufficient strength and resistance to tearing. The present invention relates to a high molecular weight aliphatic polyester copolymer and a method for producing the same.

[0002]

2. Description of the Related Art Plastics have characteristics such as low specific gravity and low corrosion resistance while having sufficient strength for practical use. In particular, general-purpose plastics are mass-produced industrially, and at the same time, are widely used in daily life and in the industrial field, and the amount of use is increasing remarkably. Since many plastics are not decomposed in the natural environment, environmental destruction due to the disposal of plastics has recently become a problem. Therefore, in recent years, there has been a demand for the development of plastics that can be biodegraded in a natural environment. Aliphatic polyesters have attracted attention as highly versatile biodegradable resins. Recently, polylactic acid (PLA), polybutylene succinate (PB)
S), polyethylene succinate (PES), polycaprolactone (PCL), and the like. Among the aliphatic polyesters, PLA is 170 at the highest.
Although it has a melting point around ℃ and has high heat resistance, it has a low elongation due to brittle nature and does not decompose in soil, so composting equipment is required. Although PBS and PES have sufficient heat resistance at a melting point of around 100 ° C., they have a low biodegradation rate, are not practically sufficient, and lack flexibility in mechanical properties. Although PCL is excellent in flexibility, its application is limited due to its low melting point of 60 ° C. and low heat resistance.
The biodegradation rate is very fast. However, such as polyethylene adipate and polycaprolactone have low melting points (6
Polymers with poor heat resistance have low utility as industrial materials, but tend to have high biodegradation rates,
It can be said that the polymer is excellent in biodegradability. 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.

[0003] As described above, it is difficult to solve the above problems with the homopolymer of the aliphatic polyester. However, the present inventors have proposed, for example, a polybutylene succinate-polycaprolactone copolymer described in Japanese Patent No. 2997756. By introducing a caprolactone unit into the aliphatic polyester copolymer as in (PBSC), practical flexibility and appropriate biodegradability can be realized, and the content of the caprolactone unit can be controlled. By doing so, it has been found that the above-mentioned problems in which the melting point is 80 ° C. or more and sufficient heat resistance is maintained and the biodegradability can be controlled can be solved. As a method for producing such an aliphatic polyester copolymer, a method based on a direct polycondensation method is disclosed in the same publication and is a very useful method. However, in such a method, the aliphatic polyester copolymer is produced by a dehydration reaction or a transesterification reaction. Since it is necessary to sufficiently remove water and diol from the reaction system, a long polymerization time may be required to increase the molecular weight. When the molecular weight is low, it is not enough to process as a fiber or a film.

[0004] One use of aliphatic polyesters is in biodegradable agricultural multi-films. Currently, polyethylene is used for this purpose. When a similar film was made with a conventional aliphatic polyester, the strength was low. As shown in JP-A-5-295071, 3
Although a method using a copolymer component having a functionality higher than that is disclosed, there is a problem that the risk of gelation during production is high, and the resulting film has a high elastic modulus and is hard and difficult to stretch. As shown in Japanese Patent No. 2825969, by a method of chain-extending an aliphatic polyester,
Although it is possible to increase the molecular weight and obtain a film having a high tensile strength, there is a problem that the film is easily torn. As a method for improving these, Japanese Patent Application Laid-Open No. H10-204
Japanese Patent Publication No. 167 proposes an aliphatic polyester having a physical property of elongation at break of 10% or more when measured at a tensile speed of 1,000 mm / min and having a branched hydrocarbon group. However, the polyester of this technology has a higher modulus of elasticity and yield strength than polyethylene widely used for films at present, and has insufficient elongation at break. It was easy to tear.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a biodegradable, high-molecular-weight aliphatic polyester copolymer capable of forming a film or sheet having mechanical properties close to that of polyethylene.

[0006]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a dicarboxylic acid having a divalent aliphatic group having 1 to 12 carbon atoms and a dicarboxylic acid having 1 to 12 carbon atoms. When copolymerizing a diol having a divalent aliphatic group and a lactone having a divalent aliphatic group having 1 to 10 carbon atoms, at least one of these dicarboxylic acids, diols and lactones has at least one of divalent aliphatic groups. It has been found that the above problem can be solved by including a specific amount of the branched divalent aliphatic group, and the present invention has been completed.

That is, the first aspect of the present invention is that the molecular chain has a general formula (1): (-CO-R ¹ -COO-R ² -O-) (1) (wherein, R ¹ has 1 to ¹ carbon atoms) A repeating unit (P) represented by 12 divalent aliphatic groups, R ² represents a divalent aliphatic group having 2 to 12 carbon atoms), and a general formula (2): (—CO—R ³ —O -) (2) (wherein, R ³ represents a divalent aliphatic group having 1 to 10 carbon atoms)
In consists repeating units (Q) represented, R ^1, at least one divalent aliphatic group of R ² and R ^3, R ^1, R ² and total 100 mole% of divalent aliphatic group R ³ For
Provided is a high-molecular-weight aliphatic polyester copolymer containing 0.01 to 50 mol% of a branched divalent aliphatic group. The second aspect of the present invention is that the high molecular weight aliphatic polyester copolymer is based on 100 parts by weight of a low molecular weight aliphatic polyester copolymer (weight average molecular weight of 5,000 or more) which is a polymerization intermediate of the copolymer. 0.1 to 5 parts by weight of the general formula (7): X ¹ -R ⁷ -X ² (7) (wherein X ¹ and X ² are a reaction capable of forming a covalent bond by acting on a hydroxyl group or a carboxyl group) And the group R ⁷ represents a single bond, an aliphatic group or an aromatic group having 1 to 20 carbon atoms, and X ¹ and X ² may be the same or different.) The present invention provides a high molecular weight aliphatic polyester copolymer according to the first aspect of the present invention, wherein The third aspect of the present invention is that the weight average molecular weight is 40,000 to 700,0.
The present invention provides the high-molecular-weight aliphatic polyester copolymer according to the first or second aspect of the present invention, which is characterized by being 00. A fourth aspect of the present invention is characterized in that R ¹ is a succinic acid residue [(CH ₂ ) ₂ ] and / or adipic acid residue [(CH ₂ ) ₄ ]. The invention provides a high molecular weight aliphatic polyester copolymer as described. A fifth aspect of the present invention is that R ² is an ethylene glycol residue [(CH ₂ ) ₂ ] and / or 1,4
- providing butanediol residue [(CH _{2) 4]} high molecular weight aliphatic polyester copolymer of the first aspect of the present invention, which is a. A sixth aspect of the present invention provides the high-molecular-weight aliphatic polyester copolymer according to the first aspect of the present invention, wherein R ³ is an ε-oxycaproic acid residue. A seventh aspect of the present invention is that the branched divalent aliphatic group has 1 carbon atom.
(I) succinic acid residue, glutaric acid residue, adipic acid residue, pimelic acid residue, suberic acid residue, azelaic acid residue or sebacic acid substituted with at least one of alkyl groups or alkoxyl groups of Residues; (ii) ethylene glycol residues, 1,3-propanediol residues, or 1,
3- or 1,4-butanediol residue; (iii) glycolic acid residue, hydroxypropionic acid residue, hydroxybutyric acid residue, hydroxyvaleric acid residue or hydroxycaproic acid residue, the first description of the present invention. A high molecular weight aliphatic polyester copolymer of Eighth of the present invention is
The reactive group of the bifunctional linking agent (E) represented by the general formula (7) is an isocyanate group; an isothiocyanate group; an epoxy group; an oxazoline group; an oxazolone group or an oxazinone group; an aziridine group; A high-molecular-weight aliphatic polyester copolymer according to the second aspect of the present invention is provided. A ninth aspect of the present invention is a compound represented by the general formula (3): R ⁴ —OCO—R ¹ —COO—R ⁵ (3) (wherein, R ¹ is a divalent aliphatic group having 1 to 12 carbon atoms, R ⁴ , R
⁵ represents a hydrogen atom or an aliphatic or aromatic group having 1 to 6 carbon atoms, and R ⁴ and R ⁵ may be the same or different. )
An aliphatic dicarboxylic acid, an acid anhydride thereof, or a diester derivative thereof (A) represented by the general formula (4): HO—R ² —OH (4) (wherein, R ² represents a C ² to C 12 An aliphatic diol (B) represented by a divalent aliphatic group) and a general formula (5): R ⁶ OCO—R ³ —OH (5) (wherein, R ³ has 1 to 10 carbon atoms) Wherein R ⁶ represents a hydrogen atom or an aliphatic or aromatic group having 1 to 6 carbon atoms, or a hydroxycarboxylic acid or an ester thereof, or a general formula (6):

Embedded image (Wherein, R ³ represents a divalent aliphatic group having 1 to 10 carbon atoms)
By the polycondensation reaction of the above components (A), (B) and (C) of the lactone (C) represented by the following formula, the molecular chain is represented by the general formula (1): (—CO—R ¹ —COO—R ² — O-) (1) (wherein, R ¹ represents a divalent aliphatic group having 1 to 12 carbon atoms, and R ² represents a divalent aliphatic group having 2 to 12 carbon atoms) ( P), and general formula (2): (—CO—R ³ —O—) (2) (wherein, R ³ represents a divalent aliphatic group having 1 to 10 carbon atoms.) It consists of units (Q), R ¹ ,
At least one divalent aliphatic group for R ² and R ³ is
100 mol% in total of the divalent aliphatic groups of R ¹ , R ² and R ³
To 0.01 to 50 mol% of the branched divalent aliphatic group
The present invention provides a method for producing a high-molecular-weight aliphatic polyester copolymer, characterized by comprising: A tenth aspect of the present invention relates to the production of the high molecular weight aliphatic polyester copolymer according to the ninth aspect of the present invention, wherein the low molecular weight aliphatic polyester copolymer (weight average molecular weight of 5, 000
Above), and 100 parts by weight of the low-molecular-weight aliphatic polyester copolymer in a molten state.
X ¹ -R ⁷ -X ² (7) wherein X ¹ and X ² are a reactive group capable of forming a covalent bond by acting on a hydroxyl group or a carboxyl group; ⁷ represents a single bond, an aliphatic group having 1 to 20 carbon atoms or an aromatic group, and X ¹ and X ² may be the same or different. ) To provide a method for producing a high molecular weight aliphatic polyester copolymer, which comprises a step of increasing the weight average molecular weight to 40,000 or more. An eleventh aspect of the present invention relates to a linking agent (E) represented by the general formula (7), wherein X ¹ and X ² react with substantially only a hydroxyl group to form a covalent bond. ):

Embedded image 10. The method for producing a high molecular weight aliphatic polyester copolymer according to the tenth aspect of the present invention, which is at least one selected from the group of reactive groups represented by First of the present invention
2 is a linking agent (E) represented by the general formula (7):
General formulas (12) to (15) in which X ¹ and X ² can react with substantially only a carboxyl group to form a covalent bond

Embedded image (R ^{8 to} R ¹⁰ represent a divalent aliphatic group or an aromatic group,
Hydrogen directly attached to the ring may be substituted with aliphatic and / or aromatic groups. The present invention provides a method for producing a high-molecular-weight aliphatic polyester copolymer according to the tenth aspect, wherein the method is at least one selected from the group of reactive groups represented by the following formula: A thirteenth aspect of the present invention is that the molar ratio at the time of charging the raw materials is represented by the following formula: 1.0 ≦ [B] / [A] ≦ 2.0 (8) (where [A] is an aliphatic dicarboxylic acid, Acid anhydride,
Or [B] represents the number of moles of an aliphatic diol), and the method for producing a high molecular weight aliphatic polyester copolymer according to the ninth aspect of the present invention is provided. . A fourteenth aspect of the present invention is that the molar ratio at the time of charging the raw materials is 0.02 ≦ [C] / ([A] + [C]) ≦ 0.40 (16) (where [A] is Aliphatic dicarboxylic acids, their anhydrides,
Or a high molecular weight aliphatic polyester according to the ninth aspect of the present invention, wherein the number of moles of an ester thereof used and [C] represents the number of moles of a hydroxycarboxylic acid or an ester thereof or a lactone used. Provided is a method for producing a copolymer. A fifteenth aspect of the present invention is that the content of the aliphatic dicarboxylic acid and the aliphatic carboxylic acid contained as impurities in the aliphatic dicarboxylic acid diester (A) is kept at 0.1 mol% or less based on the aliphatic dicarboxylic acid diester. A method for producing a high molecular weight aliphatic polyester copolymer according to any one of the ninth to fourteenth aspects of the present invention, which is characterized in that:

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The high molecular weight aliphatic polyester copolymer of the present invention has a molecular chain represented by the following general formula (1): (-CO-R ¹ -COO-R ² -O-) (1) , R ¹ represents a divalent aliphatic group having 1 to 12 carbon atoms, R ² represents a divalent aliphatic group having 2 to 12 carbon atoms), and a general formula (2): ^{(-O- -CO-R 3) (} 2) ( wherein, R ³ represents a divalent aliphatic group having 1 to 10 carbon atoms)
In consists repeating units (Q) represented, R ^1, at least one divalent aliphatic group of R ² and R ^3, R ^1, R ² and total 100 mole% of divalent aliphatic group R ³ For
A high molecular weight aliphatic polyester copolymer containing 0.01 to 50 mol% of a branched divalent aliphatic group, or a low molecular weight aliphatic polyester copolymer which is a polymer intermediate of the high molecular weight aliphatic polyester copolymer Combined (weight average molecular weight 5,000
0 or more) and 0.1 to 5 parts by weight of a bifunctional linking agent (E) represented by the general formula (7) and a high molecular weight fat having a high molecular weight. A group polyester copolymer.

The raw material (A) which gives the aliphatic dicarboxylic acid residue in the above formula (1) is an aliphatic dicarboxylic acid represented by the above general formula (3), an acid anhydride thereof, or a mono- or di-acid thereof. And diesters. In the formulas (1) and (3), R ¹ represents a divalent aliphatic group having 1 to 12 carbon atoms. The divalent aliphatic group represented by R ¹ is preferably a chain or cyclic alkylene group of 2 to 8, and — (CH ₂ )
_{2 -, - (CH 2)} 4 -, - (CH 2) 6 - is a linear lower alkylene group having 2 to 6 carbon atoms and the like. Further, R ¹ can have a substituent inert to the reaction, for example, an alkoxy group or a keto group, and R ¹ can contain a hetero atom such as oxygen or sulfur in the main chain. It may contain a structure separated by a bond, a thioether bond or the like.

In the above formula (3), R ⁴ and R ⁵ represent a hydrogen atom or an aliphatic or aromatic group having 1 to 6 carbon atoms.
⁴ and R ⁵ may be the same or different. When R ⁴ and R ⁵ are hydrogen atoms, they represent aliphatic dicarboxylic acids. As the aliphatic dicarboxylic acid, for example, succinic acid, glutaric acid,
Adipic acid, pimelic acid, azelaic acid, suberic acid,
Decanedicarboxylic acid, dodecanedicarboxylic acid, sebacic acid, diglycolic acid, ketopimelic acid, malonic acid and the like. Examples of the aliphatic group represented by R ⁴ and R ⁵ include a linear or branched alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and 5 to 12 carbon atoms such as a cyclohexyl group.
A cycloalkyl group. Examples of the aromatic group represented by R ⁴ and R ⁵ include a phenyl group and a benzyl group. Among them, R ⁴ and R ⁵ are lower alkyl groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. Such dialkyl esters include, for example, dimethyl succinate, diethyl succinate, dimethyl glutarate, diethyl glutarate, dimethyl adipate, diethyl adipate, dimethyl pimerate, dimethyl azelate, dimethyl suberate, diethyl suberate, Dimethyl sebacate, diethyl sebacate, dimethyl decanedicarboxylate, dimethyl dodecanedicarboxylate, dimethyl diglycolate,
Examples thereof include dimethyl ketopimelate and dimethyl malonate. These may be used alone or in combination of two or more.

R ¹ is a branched divalent aliphatic group as a succinic acid residue, a glutaric acid residue, an adipic acid residue substituted with at least one alkyl or alkoxyl group having 1 to 4 carbon atoms. , Pimelic acid residue, suberic acid residue, azelaic acid residue, malonic acid residue or sebacic acid residue. Examples of the aliphatic dicarboxylic acids corresponding to the above include methyl or ethyl substituted succinic acid, methyl or ethyl substituted malonic acid, methyl or ethyl substituted adipic acid, and the like.

Providing the aliphatic diol residue in formula (1)
The component (B) includes an aliphatic diol. Fat
The aliphatic diol is represented by the general formula (4). formula
In formula (1) and formula (4), R^TwoRepresents a divalent aliphatic group
You. The divalent aliphatic group preferably has 2 to 12 carbon atoms.
Or 2 to 8 chain or cyclic alkylene groups.
You. Preferred alkylene groups are (CH_Two)_Two,-(CH_Two)
_Three−, (CH_Two)_FourLower alkyl having 2 to 6 carbon atoms, such as
Group. In addition, the divalent aliphatic group R^TwoIs inert to the reaction
Having a substituent such as an alkoxy group or a keto group;
Can be. R ^TwoIs a main chain of heteroatoms such as oxygen and sulfur
For example, an ether bond, a thioe
It may contain a structure separated by a tell bond or the like.
As the aliphatic diol, for example, ethylene glycol
, 1,3-propanediol, 1,4-butanediol
, Pentamethylene glycol, hexamethylene glycol
, Octamethylene glycol, decamethylene glycol
, Dodecamethylene glycol, 1,4-cyclohexyl
Sundiol, diethylene glycol, triethylene glycol
Recall, tetraethylene glycol, pentaethylene
Glycol, polyethylene glyco having a molecular weight of 1,000 or less
Can be used. These things alone
May be used in combination of two or more. Further 1,1,1
Trifunctional alky such as tris (hydroxymethyl) propane
A small amount of call may be used in combination.

Examples of the compound in which R ² is a branched divalent aliphatic group include an ethylene glycol residue, a 1,3-propanediol residue substituted with one or more alkyl or alkoxyl groups having 1 to 4 carbon atoms, Examples thereof include 1,3- or 1,4-butanediol residues, 1,3-, 1,4- or 1,5-pentanediol residues, and the like. Examples of the aliphatic diols corresponding to the above include propylene glycol, polypropylene glycol such as dipropylene glycol, 1,3-butanediol, 2-methyl-propanediol, 2-ethyl-propanediol, neopentyl glycol, 3-pentanediol and the like.

The component (C) which gives the aliphatic hydroxycarboxylic acid residue in the formula (2) is a hydroxycarboxylic acid represented by the general formula (5) or an ester thereof, or a formula (6) Lactones. The hydroxycarboxylic acid or its ester is represented by the general formula (5). In the formula (5), R ³ represents a divalent aliphatic group. Examples of the divalent aliphatic group include a chain or cyclic alkylene group having 1 to 10, preferably 2 to 8 carbon atoms. R ³ can have a substituent inert to the reaction, for example, an alkoxy group or a keto group. R ³ can contain a heteroatom such as oxygen or sulfur in the main chain, and can also have a structure separated by, for example, an ether bond or a thioether bond. In the formula (5), R ⁶ is hydrogen, an aliphatic group or an aromatic group. 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, a cycloalkyl group having 5 to 12 carbon atoms such as a cyclohexyl group, and an aromatic group. Phenyl group, benzyl group and the like. Examples of the hydroxycarboxylic acid include glycolic acid and ε-hydroxycaproic acid. Examples of the hydroxycarboxylic acid ester include, for example, the above-mentioned hydroxycarboxylic acid methyl ester, ethyl ester and the like,
Acetate ester and the like are mentioned. Examples of the lactones include those represented by the general formula (6).
In the formula (6), R ³ 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. Also, R
³ may have a substituent inert to the reaction, for example, an alkoxy group or a keto group. Further, R ³ can contain a hetero atom such as oxygen or sulfur in the main chain, and for example, can have a structure separated by an ether bond, a thioether bond, or the like. Specific examples of lactones include, for example, β-propiolactone, β-butyrolactone, γ-butyrolactone, β-valerolactone, δ-valerolactone, δ-caprolactone, ε-caprolactone, 4-methylcaprolactone, 3,5 Various methylated caprolactones such as 3,5-trimethylcaprolactone and 3,3,5-trimethylcaprolactone; β-methyl-
cyclic monomeric esters of hydroxycarboxylic acids such as δ-valerolactone, enantholactone, laurolactone; cyclic dimeric esters of the above hydroxycarboxylic acids such as glycolide, L-lactide and D-lactide;
-Dioxolan-4-one, 1,4-dioxane-3-
And cyclic ester-ethers such as 1,5-dioxepan-2-one. These may be used as a mixture of two or more monomers.

R ³ is a branched divalent aliphatic group as a glycolic acid residue, a hydroxypropionic acid residue, a hydroxybutyric acid residue substituted with at least one alkyl or alkoxyl group having 1 to 4 carbon atoms. Group, hydroxyvaleric acid residue, hydroxycaproic acid residue and the like. Examples of the branched aliphatic dicarboxylic acid include D-, L- or D, L-lactic acid, dimethyl lactic acid, hydroxypivalic acid and the like. Examples of branched lactones include 4-methylcaprolactone, 3,5,5-trimethylcaprolactone, 3,3,5-trimethylcaprolactone, L-
Lactide, D-lactide, D, L-lactide and the like.

In the present invention, at least one divalent aliphatic groups of R ^1, R ² and R ^3, the total 100 mole percent of the divalent aliphatic group of R ^1, R ² and R ^3, 0.01 to 50 mol%, preferably 0.5 to 50 mol% of the branched divalent aliphatic group
30 mol% is contained. The branched divalent aliphatic group is represented by R ¹ , R ²
And R ³ may be one kind or two or more kinds, and a plurality of groups, for example, R ¹ and R ² , R ¹ and R ³ , R ² and R ³ , R ¹ , R ¹ Each of ² and R ³ may be one kind or two or more kinds. When the above ratio of the branched divalent aliphatic group is less than 0.01 mol%, the effect of the side chain is too small and the same performance as that having no side chain is obtained, and when it exceeds 50 mol%, the obtained copolymer is obtained. The crystallinity of the resin is remarkably reduced, and the resin is not suitable as a molding resin.

The aliphatic polyester copolymer obtained by the polycondensation reaction of the three components (A), (B) and (C) in the present invention may be random or block. The monomers may be charged at once (randomly), dividedly (blocked), polymerized with a dicarboxylic acid-diol polymer with lactones, or polylactone with dicarboxylic acid and diol. (A) in the present invention,
The step (a) of synthesizing a high molecular weight aliphatic polyester copolymer by a polycondensation reaction of the components (B) and (C) comprises:
Depending on the type of raw materials used, for example, the first half may be divided into an esterification step in which the dehydration reaction mainly proceeds and a second half in which the transesterification reaction mainly proceeds in the polycondensation step. The esterification step is carried out at 80C to 250C, preferably at 100C.
At a reaction temperature of 240 ° C., more preferably 145 ° C. to 230 ° C., 0.5 to 5 hours, preferably 1 to 4 hours, 76
It is desirable to carry out under the condition of 0 to 100 Torr. The catalyst is not necessarily required, but may be added to one mole of the aliphatic dicarboxylic acid or diester used as a raw material.
It may be used in an amount of 0 ^-7 to 10 ^-3 mol, preferably 10 ^{-6 to} 5 × 10 ^-4 mol. The latter half polycondensation step is desirably completed in 2 to 10 hours, preferably 3 to 6 hours by raising the reaction temperature while reducing the pressure of the reaction system.
At a reaction temperature of 0 ° C. to 270 ° C., preferably 190 ° C. to 240 ° C., the degree of reduced pressure is preferably 3 Torr or less, more preferably 1 Torr or less. In this step, it is preferable to use a general transesterification catalyst, and 10 ^-7 to 10 ^-3 mol, preferably 10 ^{-6 to} 5 ×, per mol of the aliphatic dicarboxylic acid or diester used as a raw material is used. 1
It is used in an amount of ^0-4 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, cross-linking, coloring and the like 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 step (a), the following catalysts can be used in both the esterification step in which the dehydration reaction mainly proceeds and the polycondensation step in which the latter half of the transesterification reaction mainly proceeds. Specific examples can be given, but these catalysts may be used alone or in combination of two or more. Examples of the catalyst include various compounds of metals, for example, carboxylate, carbonate, borate, oxide, hydroxide, hydrogen compound, alcoholate, acetylacetonate chelate and the like. Examples of the metals include alkali metals such as lithium and potassium; alkaline earth metals such as magnesium, calcium and barium;
Typical metals such as tin, antimony and germanium; transition metals such as lead, zinc, cadmium, manganese, cobalt, nickel, zirconium, titanium and iron; lanthanide metals such as bismuth, niobium, lanthanum, samarium, europium, erbium, ytterbium, etc. Is mentioned. As the catalyst, a nitrogen-containing basic compound, boric acid, a borate ester, or the like is also used. Specifically, as the alkali metal compound, 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, sodium borohydride, lithium benzoate, sodium dihydrogen phosphate, Examples thereof include potassium dihydrogen phosphate and lithium dihydrogen phosphate. As alkaline earth metal compounds, calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate,
Examples include calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate. Typical metal compounds include dibutyltin hydroxide, dibutyltin dilaurate, antimony trioxide, germanium oxide, bismuth hydroxide carbonate, bismuth hydroxide acetate and the like. Transition metal compounds include lead acetate, zinc acetate, zinc acetylacetonate, cadmium acetate, manganese acetate, manganese acetylacetonate, cobalt acetate, cobalt acetylacetonate, nickel acetate, nickel acetylacetonate, zirconium acetate, zirconium acetylacetate. , Titanium acetate, tetrabutoxytitanate, tetraisopropoxytitanate, titanium hydroxyacetylacetonate, iron acetate, iron acetylacetonate,
Niobium acetate and the like can be mentioned. As rare earth compounds,
Lanthanum acetate, samarium acetate, europium acetate, erbium acetate, ytterbium acetate and the like can be mentioned.
Specific examples of the nitrogen-containing basic compound include organic ammonium hydroxides derived from aliphatic amines and aromatic amines such as tetraethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, and trimethylbenzylammonium hydroxide. Tertiary amines such as trimethylamine, triethylamine, dimethylbenzylamine and triphenylamine; R ₂ NH (where R is an alkyl group such as methyl and ethyl, and an aryl group such as phenyl and toluyl); grade amines, primary amines represented by RNH ₂ (wherein R is as defined above); ammonia, tetramethylammonium borohydride, tetrabutylammonium borohydride, tetrabutylammonium Niu Tetraphenylborate, basic compounds such as tetramethylammonium tetraphenylborate, and the like. Of these, tetraalkylammonium hydroxides are particularly preferred. Specific examples of the borate ester include trimethyl borate, trihexyl borate, triheptyl borate, triphenyl borate, tritolyl borate, and trinaphthyl borate.

In the step (a) of synthesizing the low molecular weight aliphatic polyester copolymer (D), the charging ratio of the raw materials (A) and (B) is adjusted so as to satisfy the following conditional expression (8). It is desirable to choose. 1.0 ≦ [B] / [A] ≦ 2.0 (8) (where [A] is the number of moles of the component (A), and [B] is (B)
When the value of [B] / [A] is smaller than 1, the hydrolysis reaction proceeds due to the presence of excess acid,
When it is difficult to obtain the aliphatic polyester copolymer (D) having a desired molecular weight, and when the value of [B] / [A] is larger than 2, the molecular weight at the end of the first half esterification step is excessively small, A long reaction time is required for the latter polycondensation step.

In the present invention, it is desirable to select the charging ratio of the raw materials (A) and (C) so as to satisfy the following conditional expression (16). 0.02 ≦ [C] / ([A] + [C]) ≦ 0.40 (16) (where, [A] is the number of moles of the component (A) used, and [C] is the number of moles of the component (C). The number of moles used is shown.) [C] / ([A] + [C]) in the above formula is a repeating unit represented by the formula (2) contained in the aliphatic polyester copolymer of the present invention. It represents the molar fraction (q) of Q. If this value is less than 0.02, the resulting polymer will be hard with high crystallinity and inflexibility, and will be slow and insufficient in terms of biodegradability. On the other hand, if it is larger than 0.40, the resulting polymer has a low melting point and extremely low crystallinity, so that it has no heat resistance and is not practical.

In the present invention, in order to finally obtain an aliphatic polyester copolymer having practical strength, the low molecular weight aliphatic polyester copolymer (D) in the molten state is represented by the above formula (7). The weight average molecular weight can be increased to 40,000 or more by adding a bifunctional linking agent (E).
JP-A-4-189822 and JP-A-4-189823
According to the publication, aliphatic dicarboxylic acids, acid anhydrides thereof,
Or a method of synthesizing a low-molecular-weight aliphatic polyester from a derivative thereof and an aliphatic diol and adding a diisocyanate compound to increase the molecular weight is disclosed, but as in the present invention, an aliphatic dicarboxylic acid, an acid anhydride thereof There is no example in which the present invention is applied to a system using, as a raw material, an ester (A), an aliphatic diol (B), and a hydroxycarboxylic acid or a hydroxycarboxylic acid ester or a lactone (C) as a raw material.

The low molecular weight aliphatic polyester copolymer (D) obtained in the polymerization step (a) has a weight average molecular weight of 5,
It is preferably at least 000, more preferably at least 10,000, the sum of the acid value and the hydroxyl value is between 1.0 and 45, and the acid value is desirably at most 30. The sum of the acid value and the hydroxyl value of the copolymer (D) is the copolymer (D)
And the weight average molecular weight is 5,
When it is 000 or more, the total of the acid value and the hydroxyl value is substantially 45 or less. When the sum of the acid value and the hydroxyl value is greater than 45, the molecular weight of the copolymer (D) is low, and a large amount of a linking agent is required to increase the molecular weight to a desired molecular weight by adding a linking agent. . When a large amount of the linking agent is used, problems such as gelation are likely to occur. When the sum of the acid value and the hydroxyl value is 1.0 or less, the viscosity in a molten state increases because the molecular weight of the copolymer (D) is high. In this case, the amount of the linking agent used is extremely small, so that it is difficult to make the reaction uniform, and problems such as gelation are liable to occur. In addition, when the melting temperature is raised for the purpose of causing a uniform reaction, problems such as thermal decomposition, crosslinking, and coloring of the polymer occur.

The linking agent (E) used in the present invention is represented by the above formula (7). As the reactive groups X ¹ and X ² of the linking agent (E), the reactive groups represented by the formulas (9) to (11) capable of forming a covalent bond by reacting substantially only with a hydroxyl group, and / or It can be selected from the group of the 3- to 8-membered cyclic reactive groups represented by the above formulas (12) to (15), which can form a covalent bond by reacting substantially only with a carboxyl group. X
¹ and X ² may be the same or different.

Specific examples of the linking agent (E) into which the isocyanate group represented by the formula (9) has been introduced include a series of diisocyanate compounds. Specifically, tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, naphthylene diisocyanate, hexamethylene diisocyanate,
Hydrogenated diphenylmethane diisocyanate, lysine diisocyanate, triphenylmethane diisocyanate, trans-cyclohexylene 1,4-diisocyanate,
Examples thereof include diisocyanate compounds such as p-phenylene diisocyanate and isophorone diisocyanate, and modified allophanates, burettes, modified isocyanurates, modified polyols, and modified adducts with polythiol. Particularly preferred diisocyanate compounds include non-yellowing isocyanate compounds such as xylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. Such diisocyanate compounds may be used alone or in combination of two or more.

Specific examples of the linking agent (E) into which the isothiocyanate group represented by the formula (10) has been introduced include a series of diisothiocyanate compounds. Specifically, p-phenylenediisothiocyanate, heptamethylenediisothiocyanate, 4,4′-
Methylene diphenyl isothiocyanate, isophthaloyl isothiocyanate and the like can be mentioned. Such diisothiocyanate compounds may be used alone or in combination of two or more.

Specific examples of the linking agent (E) into which the epoxy group represented by the formula (11) has been introduced include a series of diepoxy compounds. Specifically, bisphenol-type epoxy compounds such as bisphenol A diglycidyl ether, novolak-type epoxy compounds such as phenol novolak and cresol novolak, resorcinol-type epoxy compounds, alicyclic compounds such as vinylcyclohexene dioxide and dicyclopentadiene oxide,
Glycidyl ethers, polyepoxidized polybutadiene and the like can be mentioned. Such diepoxy compounds may be used alone or in combination of two or more.

The group represented by the above formula (12) includes
Oxazoline in which R ⁸ is an ethylene group is preferable, and oxazoline can be produced by a method such as reaction of carboxylic acid with ethanolamine to prepare the linking agent (4). Particularly, bisoxazoline compounds are preferred. Specific examples of the bisoxazoline compound include 2,2'-methylenebis (2-oxazoline), 2,2'-ethylenebis (2-oxazoline), and 2,2'-ethylenebis (4-
Methyl-2-oxazoline), 2,2′-propylenebis (2-oxazoline), 2,2′-tetramethylenebis (2-oxazoline), 2,2′-hexamethylenebis (2-oxazoline), 2'-octamethylenebis (2-oxazoline), 2,2'-p-phenylenebis (2-oxazoline), 2,2'-p-phenylenebis (4-methyl-2-oxazoline), 2,2 ' -P-
Phenylenebis (4, -dimethyl-2-oxazoline), 2,2′-p-phenylenebis (4-phenyl-
2-oxazoline), 2,2′-m-phenylenebis (2-oxazoline), 2,2′-m-phenylenebis (4-methyl-2-oxazoline), 2,2′-m-phenylenebis (4 , 4-dimethyl-2-oxazoline), 2,2'-m-phenylenebis (4-phenyl-
2-oxazoline), 2,2'-o-phenylenebis (2-oxazoline), 2,2'-phenylbis (4-
Methyl-2-oxazoline), 2,2'-bis (2-oxazoline), 2,2'-bis (4-methyl-2-oxazoline), 2,2'-bis (4-ethyl-2-oxazoline) , 2,2'-bis (4-phenyl-2-oxazoline) and the like. Such bisoxazoline compounds may be used alone or in combination of two or more. Of these bisoxazoline compounds, preferred are those containing an aromatic ring group, more preferably those containing a phenylene group. Particularly preferably, 2,2'-m
-Phenylenebis (2-oxazoline) and 2,2'-
p-phenylenebis (2-oxazoline).

The group represented by the formula (13) includes R ⁹
Oxazolone wherein m is methylene and oxazinone which is ethylene are preferred. These groups are N-acyl-α or β
-It can be easily prepared by dehydrating an aminocarboxylic acid with, for example, acetic anhydride or the like. Examples of the bisoxazolone compound into which the group represented by the formula (15) is introduced include the following examples.
2,2′-bis (5 (4H) -oxazolone), 2,
2'-methylenebis (5 (4H) -oxazolone),
2,2′-ethylenebis (5 (4H) -oxazolone), 2,2′-tetramethylenebis (5 (4H) -oxazolone), 2,2′-hexamethylenebis (5 (4
H) -oxazolone), 2,2′-decamethylenebis (5 (4H) -oxazolone), 2,2′-p-phenylenebis (5 (4H) -oxazolone), 2,2′-m
-Phenylenebis (5 (4H) -oxazolone), 2,
2′-naphthalenebis (5 (4H) -oxazolone),
2,2'-diphenylenebis (5 (4H) -oxazolone), 2,2 '-(1,4-cyclohexylene) -bis (5 (4H) -oxazolone), 2,2'-bis (4-
Methyl-5 (4H) -oxazolone), 2,2′-methylenebis (4-methyl-5 (4H) -oxazolone),
2,2′-ethylenebis (4-methyl-5 (4H) -oxazolone), 2,2′-tetramethylenebis (4-methyl-5 (4H) -oxazolone), 2,2′-hexamethylenebis ( 4-methyl-5 (4H) -oxazolone), 2,2′-decamethylenebis (4-methyl-5
(4H) -oxazolone), 2,2′-p-ferrenbis (4-methyl-5 (4H) -oxazolone), 2,
2'-m-phenylenebis (4-methyl-5 (4H)-
Oxazolone), 2,2′-naphthalenebis (4-methyl-5 (4H) -oxazolone), 2,2′-diphenylenebis (4-methyl-5 (4H) -oxazolone),
2,2 '-(1,4-cyclohexylene) -bis (4-
Methyl-5 (4H) -oxazolone), 2,2′-bis (4,4-dimethyl-5 (4H) -oxazolone),
2,2′-methylenebis (4,4-dimethyl-5 (4
H) -oxazolone), 2,2′-ethylenebis (4,4)
4-dimethyl-5 (4H) -oxazolone), 2,2 '
-Tetramethylenebis (4,4-dimethyl-5 (4H)
-Oxazolone), 2,2'-hexamethylenebis (4,4-dimethyl-5 (4H) -oxazolone),
2,2'-octamethylenebis (4,4-dimethyl-5
(4H) -oxazolone), 2,2′-decamethylenebis (4,4-dimethyl-5 (4H) -oxazolone),
2,2′-p-phenylenebis (4,4-dimethyl-5
(4H) -oxazolone), 2,2′-m-phenylenebis (4,4-dimethyl-5 (4H) -oxazolone), 2,2′-naphthalenebis (4,4-dimethyl-
5 (4H) -oxazolone), 2,2′-diphenylenebis (4,4-dimethyl-5 (4H) -oxazolone), 2,2 ′-(1,4-cyclohexylene) -bis (4,4 -Dimethyl-5 (4H) -oxazolone),
2,2'-bis (4-isopropyl-5 (4H) -oxazolone), 2,2'-methylenebis (4-isopropyl-5 (4H) -oxazolone), 2,2'-ethylenebis (4-isopropyl- 5 (4H) -oxazolone), 2,2′-tetramethylenebis (4-isopropyl-5 (4H) -oxazolone), 2,2′-hexamethylenebis (4-isopropyl-5 (4H) -oxazolone), 2,2′-p-phenylenebis (4-isopropyl-5 (4H) -oxazolone), 2,2′-m-phenylenebis (4-isopropyl-5 (4H) -oxazolone), 2,2′-naphthalene Bis (4-isopropyl-5 (4H) -oxazolone), 2,2′-bis (4
-Isobutyl-5 (4H) -oxazolone), 2,2 '
-Methylenebis (4-isobutyl-5 (4H) -oxazolone), 2,2'-ethylenebis (4-isobutyl-
5 (4H) -oxazolone), 2,2′-tetramethylenebis (4-isobutyl-5 (4H) -oxazolone), 2,2′-hexamethylenebis (4-isobutyl-5 (4H) -oxazolone), 2,2'-p-phenylenebis (4-isobutyl-5 (4H) -oxazolone), 2,2'-m-phenylenebis (4-isobutyl-5 (4H) -oxazolone), 2,2'-naphthalene Bis (4-isobutyl-5 (4H) -oxazolone) and the like. Examples of the bisoxazinone compound, which is another typical compound into which the group represented by the formula (13) is introduced, include the following. 2,2′-bis (3,1-benzoxazin-4-one), 2,2′-methylenebis (3,1
-Benzoxazin-4-one), 2,2'-ethylenebis (3,1-benzoxazin-4-one), 2,
2′-tetramethylenebis (3,1-benzoxazin-4-one), 2,2′-hexamethylenebis (3,1
-Benzoxazin-4-one), 2,2'-decamethylenebis (3,1-benzoxazin-4-one),
2,2'-p-phenylenebis (3,1-benzoxazin-4-one), 2,2'-m-phenylenebis (3,1-benzoxazin-4-one), 2,2'-
Naphthalenebis (3,1-benzoxazin-4-one), 2,2 ′-(4,4′-diphenylene) bis (3,1-benzoxazin-4-one), 2,2′-
(1,4-cyclohexylene) bis (3,1-benzoxazin-4-one), 2,2′-bis (4,4-dihydro-1,3,6H-oxazin-6-one), 2,
2'-methylenebis (4,5-dihydro-1,3,6H
-Oxazin-6-one), 2,2'-ethylenebis (4,5-dihydro-1,3,6H-oxazine-6-
On), 2,2'-tetramethylenebis (4,5-dihydro-1,3,6H-oxazin-6-one), 2,
2′-p-phenylenebis (4,5-dihydro-1,
3,6H-oxazin-6-one), 2,2'-m-phenylenebis (4,5-dihydro-1,3,6H-oxazin-6-one), 2,2'-bis (4-methyl -5
-Hydro-1,3,6H-oxazin-6-one),
2,2′-ethylenebis (4-methyl-5-hydro-
1,3,6H-oxazin-6-one), 2,2′-o
-Phenylenebis (4-methyl-5-hydro-1,3,3
6H-oxazin-6-one), 2,2'-m-phenylene (4-methyl-5-hydro-1,3,6H-oxazin-6-one), 2,2'-p-phenylenebis (4
-Hydro-5-methyl-1,3,6H-oxazine-6
On), 2,2'-m-phenylenebis (4-hydro-
5-methyl-1,3,6H-oxazin-6-one) and the like.

The aziridine group represented by the formula (14) can be easily produced by reacting ethyleneimine with acid chloride or the above-mentioned diisocyanate compound. The lactam group represented by the formula (15) includes R ¹⁰
Are preferably pyrrolidone, which is trimethylene, piperidone, which is tetramethylene, and caprotactam, which is pentamethylene, and can be easily produced by reacting a lactam with an acid chloride or an isocyanate compound in the same manner as in the formula (14). Examples of the acid chloride used in these reactions include derivatives such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, and succinic acid.

The reactive groups X ¹ and X ² of the linking agent (E) are selected from the group of reactive groups represented by the above formulas (9) to (11) which can form a covalent bond by substantially reacting only with a hydroxyl group. In this case, the precursor is a low molecular weight aliphatic polyester copolymer (D)
Has an acid value of 2.0 or less, preferably 1.0 or less. When the acid value is larger than 2.0, the concentration of the hydroxyl group terminal of the copolymer (D) is low, and the ligation reaction cannot be performed efficiently, or the acid value of the final product after the ligation reaction is large,
There arises a problem that the molecular weight tends to decrease during molding. The above formula (1), which can form a covalent bond by reacting the reactive groups X ¹ and X ² of the linking agent (E) substantially only with the carboxyl group
When selected from the group of cyclic reactive groups having 3 to 8 members represented by 2) to (15), the acid value of the copolymer (D) is preferably 0.5 or more and 30 or less. When the acid value is smaller than 0.5, the amount of the linking agent used is extremely small, so that it is difficult to make the reaction uniform. When the acid value is larger than 30, problems such as a difficulty in lowering the acid value of the final product and a risk of gelation using a large amount of a linking agent occur.

The reaction between the linking agent (E) and the copolymer (D) is as follows:
It is desirable that the copolymer (D) is carried out in a uniform molten state or in a state containing a small amount of solvent, under conditions that can be easily stirred. The amount of the coupling agent (E) used is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the copolymer (D). If the amount of the coupling agent (E) is smaller than this,
It is difficult to obtain a final product having a desired molecular weight.

The high molecular weight aliphatic polyester copolymer of the present invention has a weight average molecular weight of 40,000 or more, 700,
000 or less, usually in the range of 100,000 to 400,000. Further, the melting point is usually as high as 80 ° C. or more, and the difference between the melting point and the decomposition temperature is as large as 100 ° C. or more, so that thermoforming is easy. In the aliphatic polyester copolymer of the present invention, in particular, R in the general formula (1)
Those in which ¹ and R ² are (CH ₂ ) ₂ or (CH ₂ ) ₄ and R ³ is (CH ₂ ) ₅ have a high melting point and high crystallinity.

In the present invention, another biodegradable resin (b) and a resin additive (d) can be added as required.
As the other biodegradable resin, a synthetic and / or natural polymer is used. Examples of the synthetic polymer include aliphatic polyester, polyamide, polyamide ester, biodegradable cellulose ester, polypeptide, polyvinyl alcohol, and a mixture thereof. The synthetic aliphatic polyester resin is a polyester resin other than the lactone resin, and is an aliphatic polyester resin obtained by a condensation polymerization system. Hereinafter, the synthetic aliphatic polyester resin is simply referred to as an aliphatic polyester resin, and in the case of a naturally occurring resin, this is clearly indicated. Examples of the aliphatic polyester resin include biodegradable polyester resins such as synthetic polylactic acid, polyethylene succinate, and polybutylene succinate (such resins include low molecular weight aliphatic resins represented by Bionole of Showa Polymer Co., Ltd.). Examples thereof include polyester resins synthesized from dicarboxylic acids and low molecular weight aliphatic diols), and JP-A-9-2.
No. 35360, 9-2333956, terpolymer aliphatic polyesters described in JP-A-7-17772
No. 6, lactic acid and hydroxycarboxylic acid copolymers. As biodegradable cellulose esters,
Organic acid esters such as cellulose acetate, cellulose butyrate, and cellulose propionate; inorganic acid esters such as cellulose nitrate, cellulose sulfate, and cellulose phosphate;
Hybrid esters such as cellulose acetate butyrate, cellulose acetate phthalate and cellulose nitrate acetate can be exemplified. These cellulose esters can be used alone or in combination of two or more. Among these cellulose esters, organic acid esters, particularly cellulose acetate, are preferred. Examples of the polypeptide include polyamino acids such as polymethylglutamic acid and polyamide esters. Examples of polyamide esters include resins synthesized from ε-caprolactone and ε-caprolactam. As an example of the synthetic polymer, for example, an aliphatic polyester resin has a number average molecular weight of 20,000 to 200,000 in terms of standard polystyrene by GPC.
0 or less, preferably 40,000 or more can be used.

The natural polymers include starch, cellulose,
Examples include paper, pulp, cotton, hemp, wool, silk, leather, carrageenan, chitin / chitosan, natural linear polyester resin, or a mixture thereof. Examples of the starch include raw starch, processed starch, and a mixture thereof. As raw starch, corn starch, potato starch, sweet potato starch,
Wheat starch, cassava starch, sago starch, tapioca starch, rice starch, legume starch, kudzu starch, bracken starch, lotus starch, sis starch, and the like. , Moist heat-treated starch, etc.), enzyme-modified starch (hydrolyzed dextrin, enzyme-decomposed dextrin, amylose, etc.), chemically-modified starch (acid-treated starch, hypochlorite-oxidized starch, dialdehyde starch, etc.), chemically-modified starch derivative ( Esterified starch, etherified starch, cationized starch, cross-linked starch, etc.). Among the above, as the esterified starch, acetate-starch, succinate-starch, nitrate-starch, phosphate-starch, urea-phosphate-starch, xanthate-starch, acetoacetate-starch Etc .; etherified starch such as allyl etherified starch, methyl etherified starch, carboxymethyl etherified starch, hydroxyethyl etherified starch and hydroxypropyl etherified starch; etc .; cationized starch includes starch and 2-diethylaminoethyl chloride And the reaction product of starch and 2,3-epoxypropyltrimethylammonium chloride. Examples of the crosslinked starch include formaldehyde crosslinked starch, epichlorohydrin crosslinked starch, phosphoric acid crosslinked starch, and acrolein crosslinked starch.

The resin additives include a plasticizer, a heat stabilizer, a lubricant, an anti-blocking agent, a nucleating agent, a photolytic agent, a biodegradation accelerator, an antioxidant, an ultraviolet stabilizer, an antistatic agent, a flame retardant,
Dropping agents, antibacterial agents, deodorants, fillers, coloring agents, or mixtures thereof, may be mentioned.

Examples of the plasticizer include aliphatic dibasic acid esters, phthalic acid esters, hydroxy polycarboxylic acid esters, polyester plasticizers, fatty acid esters, epoxy plasticizers, and mixtures thereof. Specifically, di-2-ethylhexyl phthalate (DOP), dibutyl phthalate (DBP), diisodecyl phthalate (D
Phthalic acid esters such as IDP), adipic acid-di-2-
Adipates such as ethylhexyl (DOA) and diisodecyl adipate (DIDA), azelaic acid-
Azelaic acid esters such as di-2-ethylhexyl (DOZ), tri-2-ethylhexyl acetylcitrate,
Polyester plasticizers such as hydroxy polycarboxylic acid esters such as acetyl tributyl citrate and polypropylene glycol adipate, and these are used alone or in a mixture of two or more. The amount of these plasticizers varies depending on the application, but generally, the total amount of the high-molecular-weight aliphatic polyester copolymer and the inorganic filler is 1%.
The range of 3 to 30 parts by weight relative to 00 parts by weight is preferred. When it is a film, the range is preferably 5 to 15 parts by weight. If the amount is less than 3 parts by weight, the elongation at break or the impact strength is reduced, and if it exceeds 30 parts by weight, the strength at break or the impact strength may be reduced.

As the heat stabilizer used in the present invention, there is an aliphatic carboxylate. As the aliphatic carboxylic acid, an aliphatic hydroxycarboxylic acid is particularly preferred. As the aliphatic hydroxycarboxylic acid, naturally occurring ones such as lactic acid and hydroxybutyric acid are preferable. Examples of the salt include salts of sodium, calcium, aluminum, barium, magnesium, manganese, iron, zinc, lead, silver, copper and the like. These can be used as one kind or as a mixture of two or more kinds. The amount added is 0.5 to 10 parts by weight based on 100 parts by weight of the high molecular weight aliphatic polyester copolymer.
It is in the range of parts by weight. When using a heat stabilizer in the above range,
The impact strength (Izod impact value) is improved, and there is an effect that the variation in elongation at break, strength at break, and impact strength is reduced.

The lubricant used in the present invention includes an internal lubricant,
Those generally used as an external lubricant can be used. For example, fatty acid esters, hydrocarbon resins, paraffins, higher fatty acids, oxy fatty acids, fatty acid amides, alkylene bis fatty acid amides, aliphatic ketones, fatty acid lower alcohol esters, fatty acid polyhydric alcohol esters, fatty acid polyglycol esters, fatty alcohols, Examples include hydric alcohols, polyglycols, polycricerols, metal soaps, modified silicones, or mixtures thereof. Preferably, fatty acid esters, hydrocarbon resins and the like are used. When selecting a lubricant, it is necessary to select a lubricant whose melting point is lower than the melting point of the lactone resin or other biodegradable resin. For example, considering the melting point of the aliphatic polyester resin, the fatty acid amide is 160 ° C.
The following fatty acid amides are selected. The compounding amount is, for example, in the case of a film, the high molecular weight aliphatic polyester copolymer 10
0.05 to 5 parts by weight of a lubricant is added to 0 parts by weight. If the amount is less than 0.05 parts by weight, the effect is insufficient, and
If the amount is more than the weight part, it will not be wound around the roll and the physical properties will be reduced. For film, from the viewpoint of preventing environmental pollution, it is highly safe and FDA (US Food and Drug Administration)
Preferred are ethylene bisstearic acid amide, stearic acid amide, oleic acid amide, and erucic acid amide registered under the trade name.

Examples of the photodegradation accelerator include benzophenones such as benzoins, benzoin alkyl ethers, benzophenone and 4,4-bis (dimethylamino) benzophenone and derivatives thereof; acetophenone,
Acetophenones such as α, α-diethoxyacetophenone and derivatives thereof; quinones; thioxanthones; photoexciting materials such as phthalocyanine, anatase-type titanium oxide, ethylene-carbon oxide copolymer, sensitization of aromatic ketones with metal salts And the like. These photolysis accelerators are
One or two or more can be used in combination.

Examples of the biodegradation promoter include oxo acids (for example, oxo acids having about 2 to 6 carbon atoms such as glycolic acid, lactic acid, citric acid, tartaric acid, and malic acid), saturated dicarboxylic acids (for example, Organic acids such as acids, malonic acid, succinic acid, succinic anhydride, glutaric acid, etc .; lower saturated dicarboxylic acids having about 2 to 6 carbon atoms); lower acids of these organic acids and alcohols having about 1 to 4 carbon atoms; Alkyl esters are included. Preferred biodegradation accelerators include organic acids having about 2 to 6 carbon atoms, such as citric acid, tartaric acid, and malic acid, and coconut shell activated carbon. These biodegradation accelerators are 1
Species or two or more can be used in combination.

Examples of the fillers (including fillers) include various fillers, such as mica, calcium silicate, fine powdered silica (anhydride), and white carbon (hydrated), in addition to the above-mentioned calcium carbonate and talc. And inorganic fillers such as asbestos, porcelain clay (baked), barley stone, various titanium oxides and glass fibers, and organic fillers such as particles of natural materials. The finely divided silica as the inorganic filler may be silica produced by a wet method or silica produced by high-temperature hydrolysis of silicon tetrachloride in an oxyhydrogen flame, but preferably has a particle size of 50 nm or less. . Organic fillers include fine powder particles made of paper having a diameter of 50 microns or less. The amount of the organic filler added is the same as in the case of the inorganic filler. Examples of the extender include wood flour, glass balloon and the like. The amount of the filler added is the same as in the case of the inorganic filler.

Various molded articles can be obtained by molding the biodegradable resin composition of the present invention. Molding includes primary molding into preforms such as pellets, plates, parisons and the like, sheets, films, and tapes (including uniaxially or biaxially stretched products, and transparency and mechanical strength are improved by stretching). Secondary molding into thin-walled containers, thick-walled containers, fibers (including stretched materials, transparency and mechanical strength are improved by stretching), and furthermore, films into bags, especially degradable garbage bags, draining bags, shrink films ( It may be directly formed into a film.) Perforated film, agricultural multi (weedproof) film, vegetation film, solid film, root wrapping sheet, drainage sheet,
Curing sheet, etc .; Laminate film for card, etc., bubble buffer sheet, foldable cushioning material; Fiber for thread, rope, disposable fabric, fishing line, net, fishing net, cold gauze, non-woven fabric, etc .;
Non-woven fabric for disposable diapers, sanitary products, towels, oil absorbing materials, filters, etc .; tape for packing tapes, nets,
For bands, etc .; Nets for civil engineering reinforcement, planting, medical products; Thin containers for trays, blister packs, etc .; Thick containers for bottles, planting containers, etc .; For materials; Foams for cushioning materials, agricultural materials, etc .; Coating of granular fertilizers for sustained release and slow release, microcapsules for pharmaceuticals, pesticides, etc .; Industrial materials such as fasteners, formwork, plant protection materials, containers (beverages, food, machinery / electrical products, agricultural products, pharmaceuticals, seedling pots); household items such as tableware, knives, forks, spoons, and trays; Medical supplies such as;
Office supplies such as pen barrels and files; Information media materials such as cards; sports equipment such as outdoor goods and golf tees; leisure goods body;
It can be processed into paint and the like. Examples of the molding method include extrusion molding, injection molding, blow molding, calender molding, compression molding, transfer molding, thermoforming, flow molding, extrusion foam molding, extrusion coating and lamination molding. In the case of a film or sheet, T-die molding, inflation molding, calendar molding is usually used,
In addition, uniaxial or biaxial stretching can be performed without stretching.

[0043]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. Various measured values of the aliphatic polyester copolymer in the examples were obtained 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. Chloroform was used as an eluent. (Acid value and hydroxyl value) It measured based on JISK0070. (Thermal properties) The melting point and the glass transition point were determined by a differential scanning calorimeter (DSC). (Mechanical strength) Based on JIS K7113, the tensile elongation and strength of the test piece were determined.

(Example 1) 200 ml internal volume with stirrer
431.8 g of succinic acid in a glass four-necked flask
(A: 3.66 mol), 1,4-butanediol 36
2.5 g (B: 4.02 mol), ε-caprolactone 7
3.7 g (C: 0.65 mol) and 20.4 g of 1,3-pentanediol having a branched divalent aliphatic group (C:
0.2 mol), 546 mg of titanium tetraisopropoxide as a catalyst, magnesium diphosphate trihydrate 10
5 mg was charged and the reaction was started at 180 ° C. under a nitrogen atmosphere. After 1.0 hour, the reaction was continued while gradually increasing the reaction temperature to 240 ° C. After 4.0 hours, pressure reduction was started and the reaction was further performed for 6.0 hours. The obtained polymer had Mn: 61,200, Mw: 146,000, Mw
/ Mn: having a molecular weight of 2.4 and a molecular weight distribution, and a melting point of 9
It had a thermal property of 7 ° C. The obtained polymer is a film-formable, flexible and tough polymer having a mechanical strength of a tensile strength of 420 kgf / cm ² and a tensile elongation of 68 kg.
It was 0%.

(Example 2) Stirrer, fractionating condenser,
36.25 kg (B: 402 mol) of 1,4-butanediol and succinic acid 4 were placed in a prepolymerization tank equipped with a temperature controller.
3.18 kg (A: 366 mol), 10.43 kg of ε-caprolactone (C: 91 mol), 1.14 kg of 2-methyl-propanediol having a branched divalent aliphatic group
(10 mol) were charged all at once. Under normal pressure, 145-22
The mixture was stirred at a temperature of 5 ° C. to perform an esterification reaction. When the amount of the distillate exceeded 13.0 kg, the prepolymerization step was terminated, and the reaction solution was transferred to the main polymerization tank. Further, 54.6 g of tetraisopropyl titanate was added to the main polymerization tank, and the mixture was stirred while maintaining the reaction solution at a temperature of 210 to 220 ° C., and finally the pressure was reduced to 1.0 Torr (133 Pa), and the mixture was stirred for 6 hours. Then, 1,4-butanediol was distilled off, that is, a transesterification reaction was performed by a glycol removal reaction. The obtained low-molecular-weight polyester has a weight average molecular weight of 28,800 and an acid value of 0.6 mg-KOH / g.
Met. After the completion of the deglycolization reaction, the obtained low-molecular-weight polyester was melted at 190 ° C., and 655 g of hexamethylene diisocyanate (E: 4.2 mol) was added. When the mixture was stirred, the viscosity rapidly increased, but gelation occurred. Did not. The resulting high molecular weight aliphatic polyester copolymer had an Mw of 112,000, an acid value of 0.7 mg KOH / g, and a melting point of 94 ° C., and could be formed into a film. As for the mechanical strength, the tensile strength is 360 kgf / cm ² and the tensile elongation is 7
00%.

Example 3 30.45 k of 1,4-butanediol was placed in the same prepolymerization tank as used in Example 2.
g (B: 338 mol), 38.0 kg of succinic acid (A: 3
22 mol), 12.24 kg of ε-caprolactone (C:
107 mol), and 1.7 kg (15 mol) of 2-methyl-propanediol having a branched divalent aliphatic group were charged all at once. Under normal pressure, the mixture was stirred at a temperature of 145 to 225 ° C. to perform an esterification reaction. Distillate volume is 11.5k
g, the prepolymerization step was terminated, and the reaction solution was transferred to the main polymerization tank. Further, 48.1 g of tetraisopropyl titanate was added to the main polymerization tank, and the reaction solution was added to 210-210.
Stir at a temperature of 220 ° C. and finally 1.0 Torr
(133 Pa), and the mixture was stirred for 6 hours to carry out a glycol removal reaction (ester exchange reaction). The weight average molecular weight of the obtained low molecular weight polyester was 31,200, and the acid value was 0.8 mg-KOH / g. After the completion of the glycol removal reaction, the low molecular weight polyester was melted at 190 ° C., and 593 g of hexamethylene diisocyanate was obtained.
(E: 3.8 mol) was added and the mixture was stirred, and the viscosity increased rapidly but did not gel. The resulting high molecular weight aliphatic polyester copolymer had an Mw of 148,000, an acid value of 1.0 mg-KOH / g, and a melting point of 88 ° C., and could be formed into a film. Mechanical strength is tensile strength 320k
gf / cm ² and tensile elongation were 860%.

According to the present invention, a biodegradable high molecular weight aliphatic polyester copolymer which can be formed into a film or sheet having mechanical properties close to polyethylene is obtained. Since the high molecular weight aliphatic polyester copolymer obtained by the present invention is a sufficiently high molecular weight body, it can be formed into a film or a fiber, and has practically sufficient flexibility. Further, since the acid value is low, the molecular weight stability during molding is good, and at the same time, it has excellent biodegradability. Therefore, the high molecular weight aliphatic polyester copolymer of the present invention, a film, a fiber,
It can be used after being processed into a wide range of molded products such as sheets and bottles. After use, it can be rapidly biodegraded by means such as burying in soil and composting.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4J029 AA05 AB01 AB04 AC02 AD01 BA02 BA03 BA04 BA05 BA08 BA09 BA10 CA02 CA04 CA05 CA06 CA09 EA01 EA03 EG02 EG05 EG07 EG09 HA01 HA02 HB01 HB02 KB02 KH01

Claims (15)

[Claims] The molecular chain is represented by the general formula (1): (—CO—R ¹ —COO—R ² —O—) (1) (wherein R ¹ is a divalent aliphatic having 1 to 12 carbon atoms) A repeating unit (P) represented by a group, R ² represents a divalent aliphatic group having 2 to 12 carbon atoms), and a general formula (2): (—CO—R ³ —O—) (2) ( In the formula, R ³ represents a divalent aliphatic group having 1 to 10 carbon atoms)
In consists repeating units (Q) represented, R ^1, at least one divalent aliphatic group R ² and R ^3, R ^1, R ² and total 100 mole% of divalent aliphatic group R ³ For
A high-molecular-weight aliphatic polyester copolymer containing 0.01 to 50 mol% of a branched divalent aliphatic group. 2. The high molecular weight aliphatic polyester copolymer is a low molecular weight aliphatic polyester copolymer (weight average molecular weight of 5,000 or more), which is a polymerization intermediate of the copolymer.
0.1 to 5 parts by weight of the general formula (7): X ¹ -R ⁷ -X ² (7) (wherein X ¹ and X ² act on a hydroxyl group or a carboxyl group and are shared with each other) A reactive group capable of forming a bond, R ⁷ represents a single bond, an aliphatic group or an aromatic group having 1 to 20 carbon atoms, and X ¹ and X ² may be the same or different.) The high-molecular-weight aliphatic polyester copolymer according to claim 1, which is linked by an acidic linking agent (E). 3. A weight average molecular weight of 40,000 to 70.
The high-molecular-weight aliphatic polyester copolymer according to claim 1 or 2, wherein the molecular weight is 0.000. 4. R ¹ is a succinic acid residue [(CH ₂ ) ₂ ]
And / or residues of adipic acid [(CH _{2) 4]} high molecular weight aliphatic polyester copolymer according to claim 1, wherein it is. 5. The method according to claim 5, wherein R ² is an ethylene glycol residue [(C
H ₂ ) ₂ ] and / or 1,4-butanediol residue [(C
H _{2) 4]} high molecular weight aliphatic polyester copolymer according to claim 1, wherein it is. 6. The high molecular weight aliphatic polyester copolymer according to claim 1, wherein R ³ is an ε-oxycaproic acid residue. 7. A branched divalent aliphatic group is substituted with one or more alkyl or alkoxyl groups having 1 to 4 carbon atoms,
(I) succinic acid residue, glutaric acid residue, adipic acid residue, pimelic acid residue, suberic acid residue, azelaic acid residue or sebacic acid residue; (ii) ethylene glycol residue, 1,3- Propanediol residue or 1,3
-Or 1,4-butanediol residue; (iii) a glycolic acid residue, hydroxypropionic acid residue, hydroxybutyric acid residue, hydroxyvaleric acid residue or hydroxycaproic acid residue; Aliphatic polyester copolymer. 8. The reactive group of the bifunctional linking agent (E) represented by the general formula (7) is an isocyanate group; an isothiocyanate group; an epoxy group; an oxazoline group; an oxazolone group or an oxazinone group; The high-molecular-weight aliphatic polyester copolymer according to claim 2, which is a mixture of these groups. 9. General formula (3): R ⁴ —OCO—R ¹ —COO—R ⁵ (3) (wherein, R ¹ is a divalent aliphatic group having 1 to 12 carbon atoms, R ⁴ , R
⁵ represents a hydrogen atom or an aliphatic or aromatic group having 1 to 6 carbon atoms, and R ⁴ and R ⁵ may be the same or different. )
An aliphatic dicarboxylic acid, an acid anhydride thereof, or a diester derivative thereof (A) represented by the general formula (4): HO—R ² —OH (4) (wherein, R ² represents a C ² to C 12 An aliphatic diol (B) represented by a divalent aliphatic group) and a general formula (5): R ⁶ OCO—R ³ —OH (5) (wherein, R ³ has 1 to 10 carbon atoms) Wherein R ⁶ represents a hydrogen atom or an aliphatic or aromatic group having 1 to 6 carbon atoms, or a hydroxycarboxylic acid or an ester thereof, or a general formula (6): 1) (Wherein, R ³ represents a divalent aliphatic group having 1 to 10 carbon atoms)
By the polycondensation reaction of the above components (A), (B) and (C) of the lactone (C) represented by the following formula, the molecular chain is represented by the general formula (1): (—CO—R ¹ —COO—R ² — O-) (1) (wherein, R ¹ represents a divalent aliphatic group having 1 to 12 carbon atoms, and R ² represents a divalent aliphatic group having 2 to 12 carbon atoms) ( P), and general formula (2): (—CO—R ³ —O—) (2) (wherein, R ³ represents a divalent aliphatic group having 1 to 10 carbon atoms.) It consists of units (Q), R ¹ ,
At least one divalent aliphatic group for R ² and R ³ is
100 mol% in total of the divalent aliphatic groups of R ¹ , R ² and R ³
To 0.01 to 50 mol% of the branched divalent aliphatic group
A method for producing a high molecular weight aliphatic polyester copolymer, characterized by comprising: 10. The method for producing a high molecular weight aliphatic polyester copolymer according to claim 9, wherein a low molecular weight aliphatic polyester copolymer (weight average molecular weight of 5,000 or more), which is a polymerization intermediate of the copolymer, is used. 0.1 to 5 parts by weight of the general formula (7): X ¹ -R ⁷ -X ² (7) (100) relative to 100 parts by weight of the low molecular weight aliphatic polyester copolymer in the melting step and in the step of synthesizing. represents wherein, X ¹ and X ² hydroxyl or formed reactive groups capable of covalent bond acts as a carboxyl group, R ⁷ represents a single bond, an aliphatic group or an aromatic group having 1 to 20 carbon atoms, X ¹ , X ² may be the same or different.) By adding a bifunctional linking agent (E) represented by the formula (1) to increase the weight average molecular weight to 40,000 or more. A method for producing a polyester copolymer. 11. A linking agent (E) represented by the general formula (7)
Wherein X ¹ and X ² are capable of forming a covalent bond by reacting substantially only with a hydroxyl group, in formulas (9) to (11): The method for producing a high-molecular-weight aliphatic polyester copolymer according to claim 10, wherein the copolymer is at least one member selected from the group consisting of reactive groups represented by the following formulae. 12. A linking agent (E) represented by the general formula (7):
Wherein X ¹ and X ² can form a covalent bond by reacting substantially only with a carboxyl group. (R ^{8 to} R ¹⁰ represent a divalent aliphatic group or an aromatic group,
Hydrogen directly attached to the ring may be substituted with aliphatic and / or aromatic groups. 11. The method for producing a high-molecular-weight aliphatic polyester copolymer according to claim 10, which is at least one member selected from the group consisting of reactive groups represented by the formula: 13. The molar ratio at the time of charging raw materials is represented by the following formula: 1.0 ≦ [B] / [A] ≦ 2.0 (8) (wherein [A] is an aliphatic dicarboxylic acid and its acid anhydride object,
Or [B] represents the number of moles of the aliphatic diol), or (B) represents the number of moles of the aliphatic diol.
A method for producing the high-molecular-weight aliphatic polyester copolymer described in the above. 14. The molar ratio at the time of charging raw materials is as follows: 0.02 ≦ [C] / ([A] + [C]) ≦ 0.40 (16) (where [A] is an aliphatic Dicarboxylic acids, their anhydrides,
Or [C] represents the number of moles of hydroxycarboxylic acid or its ester or lactone).
A method for producing the high-molecular-weight aliphatic polyester copolymer described in the above. 15. An aliphatic dicarboxylic acid diester (A)
The content of aliphatic dicarboxylic acid and aliphatic carboxylic acid contained as impurities therein is maintained at 0.1 mol% or less based on the aliphatic dicarboxylic acid diester. A method for producing a high-molecular-weight aliphatic polyester copolymer described above.