JP2004137490A - Glycolic acid copolymer and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glycolic acid copolymer having high heat stability, scarcely causing discoloration even when subjected to melt molding and processing, having excellent quality, and capable of giving high barrier properties and sufficient mechanical strength to a molded product, and to provide a method for producing the same. <P>SOLUTION: This glycolic acid copolymer has a weight-average molecular weight of ≥50,000, contains glycolic acid units in an amount of not less than 80 mol% but less than 95 mol%, and satisfies the following requisites [1] and [2]: [1] hydroxycarboxylic acid units other than the glycolic acid units are contained in an amount of 5.0-20.0 mol% and an average chain length of the hydroxycarboxylic acid units other than the glycolic acid units is 1.00 to 1.50; and [2] diglycolic acid units are contained in an amount of 0-0.10 mol%. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a high molecular weight glycolic acid copolymer, a method for producing the same, and a molded product thereof. More specifically, a biodegradable high molecular weight glycolic acid copolymer having high thermal stability, little coloration during melt molding, and useful as a gas barrier material, a method for producing the same, and molding thereof About the body.

In recent years, the problem of plastic waste has been taken up from the viewpoint of protection of the natural environment, and a polymer decomposable in the natural environment and a molded article thereof have been required. Polyglycolic acid and its copolymer have excellent balance in terms of heat resistance, mechanical strength and biodegradability, and have extremely high gas barrier properties. For this reason, in recent years, it has received attention as a biodegradable polymer material for use in packaging materials such as containers and films, and the development of high molecular weight polyglycolic acid and a copolymer thereof having sufficient mechanical strength as a molded article has been promoted. ing.
However, polyglycolic acid and its copolymer containing a large number of glycolic acid units have a high melting point, so there are two problems, specifically, it is necessary to mold at a high temperature, and further, the melting point and the decomposition temperature The thermal stability has been a problem, for example, when the coloration during the melt molding process is remarkable, the heat aging resistance is poor, or a thermal decomposition product is generated due to the problem that the difference from the above is small.

As an attempt to improve the above thermal stability, methods using a phosphorus compound as a thermal stabilizer have been studied.In these methods, polyglycolic acid and a copolymer thereof having sufficient thermal stability are used. Not yet obtained.
A method of improving the thermal stability by reacting a terminal functional group with a specific compound (for example, see Patent Document 1) and the like have been studied. Although this method is effective in suppressing the depolymerization of the glycolic acid polymer during melt molding, the effect of suppressing coloration during melt molding has not been sufficient.
In general, a means for solving the above problem by lowering the melting point by performing copolymerization is a commonly used means, and various copolymers of glycolic acid polymers have been studied.

For example, as a method for obtaining a high-molecular-weight glycolic acid copolymer, glycolic acid and / or a derivative thereof is once dehydrated and condensed, and then thermally decomposed to produce a glycolic acid cyclic dimer ester (glycolide). A method for producing a glycolic acid copolymer through a number of steps of purifying to a high purity and then subjecting it to ring-opening polymerization with, for example, a lactic acid cyclic dimer ester (lactide) in the presence of a catalyst has been proposed ( For example, see Patent Document 2).
However, in the glycolic acid copolymer such as a glycolide-lactide copolymer obtained by the above ring-opening polymerization method, for example, a lactic acid unit which is a copolymerized unit is blockwise introduced into the primary structure of the resin. Tend. For this reason, when the content of the copolymer compound unit is small, the effect of sufficiently lowering the melting point cannot be obtained, and the effect of improving the coloring at the time of melt molding the copolymer is still insufficient. Was.

On the other hand, when the content of the lactic acid unit, which is a copolymer unit, is increased to further lower the melting point, the gas barrier property, which is a characteristic of the glycolic acid copolymer, tends to decrease.
Other methods for producing glycolic acid copolymers by ring-opening polymerization include copolymerization of glycolide with ε-caprolactone, trimethylene carbonate, p-dioxanone, cyclic dimer esters of glycolic acid and malic esters, and the like. A method of copolymerizing with a compound has been proposed (see Patent Documents 3, 4, 5, and 6).
On the other hand, as another polymerization method, there is a method of mainly polycondensing glycolic acid and / or a derivative thereof. The polycondensation method is industrially advantageous because the number of production steps is small compared to the ring-opening polymerization method. Further, as the glycolic acid copolymer obtained, it is possible to introduce a copolymer compound unit into the resin primary structure at random, and to introduce a small amount of a copolymer compound unit to greatly lower the melting point. The effect of improving is great. For this reason, various studies have been made so far, and glycolic acid copolymers produced by this polymerization method have been disclosed.

For example, Patent Literature 7 discloses a copolymer obtained from glycolic acid and a polycarboxylic acid containing two or more carboxyl groups in one molecule. However, there is no description about a high molecular weight substance having a weight average molecular weight of 50,000 or more.
For example, Patent Document 8 proposes a copolymer having a weight average molecular weight of 50,000 to 1,000,000, which is composed of a hydroxycarboxylic acid unit and an aliphatic dicarboxylic acid unit, and a block copolymer unit of ethylene oxide and propylene oxide. ing. Patent Document 9 proposes an aliphatic polyester copolymer having a number average molecular weight of 10,000 to 100,000, comprising an aliphatic hydroxycarboxylic acid unit, an aliphatic diol unit, and an aliphatic dicarboxylic acid unit. Patent Documents 8 and 9 both illustrate copolymers in which a lactic acid unit is used as a hydroxycarboxylic acid unit, and show examples in which fibers and sheets are formed into a copolymer. In the case of a copolymer containing a large amount, the thermal stability of the copolymer was not sufficient in all cases, and the copolymer tended to be significantly colored during melt molding.

Further, aliphatic polyesters comprising a glycol unit and a glycolic acid unit and / or a lactic acid unit and having a solution viscosity of 0.35 or more (for example, see Patent Document 10) have been proposed. The heat stability of the resin was low, and coloring during the melt molding was remarkable.
Further, a transesterification reaction of a copolymer [a] of polyglycolic acid or glycolide and lactide with a polyester [b] composed of a diglycolic acid unit and a diol compound unit (the content of [b] Copolymers obtained by weighting from 2 to 50% by mass (for example, see Patent Document 11) have been proposed, but in the case of a copolymer containing a large amount of glycolic acid units, the resulting resin Thermal stability was low, and in particular, there was a tendency to be significantly colored during melt molding.

On the other hand, several methods for producing a glycolic acid copolymer using glycolic acid and / or a derivative thereof as a raw material have been proposed.
For example, Patent Document 12 discloses that polycarboxylic acid having a weight average molecular weight of 50,000 or more is obtained by polycondensing a hydroxycarboxylic acid or an oligomer thereof in the presence of an inorganic solid acid catalyst and an alkali metal earth compound catalyst. Is disclosed. However, the resulting polyhydroxycarboxylic acid is also colored light brown, and has a quality problem. The heat stability of the polyhydroxycarboxylic acid was low, and coloring during melt molding was remarkable.

Patent Document 13 discloses a method for producing a high-molecular-weight polyglycolic acid in which a hydrolyzate of methyl glycolate is polycondensed to form a prepolymer, and then the obtained prepolymer is subjected to solid-phase polymerization. The thermal stability of the obtained resin was low, and the coloring at the time of melt molding was remarkable.
As described above, the glycolic acid copolymer containing a large amount of glycolic acid units is excellent in suppressing coloring during melt molding, and furthermore, the obtained molded article has high mechanical strength and high gas barrier properties. No polymer was known.

JP-A-56-157422 JP-A-48-62899 JP-A-3-26913 JP-B-63-47731 JP-A-9-12689 JP-A-2-209918 Japanese Patent Publication No. 7-501102 JP-A-11-255873 JP-A-8-3296 JP-A-1-156319 JP-A-52-147691 Japanese Patent Publication No. 09-808220 JP-A-11-130847

An object of the present invention is to have high thermal stability, and at the time of melt molding at a high temperature, have little coloring, have excellent quality, and a molded article obtained by melt molding has a high gas barrier property and sufficient It is an object of the present invention to provide a high molecular weight glycolic acid copolymer having mechanical strength and a method for efficiently producing the copolymer by an industrially simple method.

The present inventors have found that, when glycolic acid and / or a derivative thereof is used as a raw material, polycondensation is performed under melting conditions to produce a glycolic acid copolymer, and the side reaction represented by the chemical formula (1) is initially performed in the polycondensation. Thus, it was found that diglycolic acid units were formed, and that the content of the diglycolic acid units in the glycolic acid copolymer greatly varied depending on the production conditions.

Furthermore, as a result of earnestly examining the relationship between the primary structure of the resulting glycolic acid copolymer and the thermal stability and gas barrier properties of the copolymer, a specific amount of a hydroxycarboxylic acid unit other than the glycolic acid unit was included, It has been found that a copolymer in which the content of diglycolic acid units has been reduced to a specific amount or less and which has a weight average molecular weight of 50,000 or more solves the above problem.
When using a glycolic acid and / or a derivative thereof as a raw material and performing polycondensation under melting conditions to produce a glycolic acid copolymer, the polycondensation is performed with reaction conditions up to a specific molecular weight within a specific condition range. Thereby, the content of the diglycolic acid unit formed in the copolymer is large, and it has been found that a high-molecular-weight glycolic acid copolymer having a stably reduced content can be obtained, and the present invention has been completed. Was.

That is, the present invention is as follows.
(1) A glycolic acid copolymer having a weight average molecular weight of 50,000 or more and a glycolic acid unit content of 80 mol% or more and less than 95 mol%, which satisfies the following [1] and [2]. Glycolic acid copolymer.
[1] A hydroxycarboxylic acid unit other than the glycolic acid unit is contained in an amount of 5.0 mol% or more and 20.0 mol% or less, and the average chain length of the hydroxycarboxylic acid unit other than the glycolic acid unit is 1.00 or more and 1.50 or less. [2] Diglycolic acid unit content of 0 or 0.10 mol% or less

(2) The glycolic acid copolymer according to (1), wherein the weight average molecular weight of the glycolic acid copolymer is 80,000 or more.
(3) The glycolic acid copolymer according to (1) or (2), wherein the diglycolic acid unit content is more than 0 and 0.09 mol% or less.
(4) The glycolic acid copolymer according to any one of (1) to (3), wherein the weight average molecular weight of the glycolic acid copolymer is 100,000 or more.
(5) The glycolic acid copolymer according to any one of (1) to (4), wherein the average chain length of the hydroxycarboxylic acid units other than the glycolic acid unit is from 1.00 to 1.20. Polymer.

(6) The glycolic acid copolymer according to any one of (1) to (5), wherein the hydroxycarboxylic acid unit other than the glycolic acid unit is a monohydroxymonocarboxylic acid.
(7) The glycolic acid copolymer according to any one of (1) to (6), which contains at least a polyol unit.
(8) The method according to (7), wherein the polyol unit is at least one selected from a diol unit having 3 or more carbon atoms and a compound unit having 4 or more carbon atoms having 3 or more hydroxyl groups in one molecule. The glycolic acid copolymer according to the above.
(9) The glycolic acid copolymer according to (8), wherein the polyol unit is selected from compound units having 5 or more carbon atoms.

(10) The glycolic acid copolymer according to (9), wherein the polyol unit is a neopentyl glycol unit.
(11) The composition according to any one of (7) to (10), wherein the total content of the polyol unit and the polycarboxylic acid unit in the glycolic acid copolymer is less than 2.0 mol%. Glycolic acid copolymer.
(12) The total content of the polyol unit and the polycarboxylic acid unit is more than 0.02 mol% and less than 2.0 mol%, and the content of the polyol unit is 0.02 mol% or more and less than 2.0 mol%. (7) The glycolic acid copolymer according to any one of (7) to (11).

(13) The glycolic acid copolymer according to (1), wherein the hydroxycarboxylic acid unit other than the glycolic acid unit is a lactic acid and / or 6-hydroxyhexanoic acid unit.
(14) The method according to (1) to (13), which is obtained by polycondensation using glycolic acid and / or a derivative thereof and a compound copolymerizable with glycolic acid and / or a derivative thereof as a starting material. The glycolic acid copolymer according to any one of the above.

(15) Using a raw material comprising glycolic acid and / or a derivative thereof and a compound copolymerizable with the glycolic acid and / or a derivative thereof, including a hydroxycarboxylic acid other than glycolic acid and / or a derivative thereof, A method for producing a glycolic acid copolymer by polycondensation, comprising the following [Steps (A), (B) and (C)].
(A) A step of producing a glycolic acid copolymer having a weight-average molecular weight of 700 to 5,000 by performing a polycondensation reaction at a reaction temperature of 20 ° C to 160 ° C [Step (A)] ].
(B) Following [Step (A)], a step of raising the reaction temperature to 190 ° C. within 100 minutes [Step (B)].
(C) When producing a glycolic acid copolymer having a weight average molecular weight of 10,000 or more by performing a polycondensation reaction at a reaction temperature in a range of 190 ° C. or more and 300 ° C. or less following [Step (B)]. Subjecting the glycolic acid copolymer to a polycondensation reaction under the condition that the weight-average molecular weight increases until the weight-average molecular weight reaches 10,000 or more per hour [step (C)] ].

(16) The method according to (1) to (14), wherein the glycolic acid copolymer obtained by the method according to (15) is further polycondensed at a reaction temperature in a range of 190 ° C to 300 ° C. A method for producing the glycolic acid copolymer according to any one of the above.
(17) Polycondensation using glycolic acid and / or a derivative thereof, a hydroxycarboxylic acid other than glycolic acid and / or a derivative thereof, and if necessary, a raw material containing a polyol, a polycarboxylic acid and / or a derivative thereof. The method for producing a glycolic acid copolymer according to (15), wherein a raw material satisfying the following mathematical formulas (1), (2) and (3) is used when producing the glycolic acid copolymer by the following method.

（ただし、式中の［Ｘ−１］はグリコール酸及び／又はその誘導体の換算モル比、［Ｘ−２］はグリコール酸以外のヒドロキシカルボン酸及び／又はその誘導体の換算モル比、［Ｘ−３］、［Ｘ−４］は必要に応じて用いるポリオール、ポリカルボン酸及び／又はその誘導体の換算モル比を表し、［Ｘ−３］と［Ｘ−４］は独立して０であってもよい。）

(Where [X-1] is a reduced molar ratio of glycolic acid and / or its derivative, [X-2] is a reduced molar ratio of hydroxycarboxylic acid other than glycolic acid and / or its derivative, [X- 3] and [X-4] represent the reduced molar ratio of the polyol, polycarboxylic acid and / or derivative thereof used as needed, and [X-3] and [X-4] are independently 0. May be.)

(18) The method for producing a glycolic acid copolymer according to (17), wherein a raw material containing at least a polyol unit and satisfying the following mathematical expressions (4) and (5) is used.

（ただし、［Ｘ−１］、［Ｘ−２］、［Ｘ−３］及び［Ｘ−４］は、上記と同じ。［Ｘ−４］は０であってもよい。）

(However, [X-1], [X-2], [X-3] and [X-4] are the same as above. [X-4] may be 0.)

(19) The method for producing a glycolic acid copolymer according to (17), which satisfies the following formulas (6) and (7) in the method for producing a glycolic acid copolymer containing a polyol unit and a polycarboxylic acid unit.

（ただし、［Ｘ−１］、［Ｘ−２］、［Ｘ−３］及び［Ｘ−４］は、上記と同じ。［Ｘ−４］は０であってもよい。）

(However, [X-1], [X-2], [X-3] and [X-4] are the same as above. [X-4] may be 0.)

(20) The method for producing a glycolic acid copolymer according to (17), wherein a raw material containing at least a polyol unit and satisfying the following formula (8) is used.

（ただし、［Ｘ−１］、［Ｘ−２］、［Ｘ−３］及び［Ｘ−４］は、上記と同じ。［Ｘ−４］は０であってもよい。）

(However, [X-1], [X-2], [X-3] and [X-4] are the same as above. [X-4] may be 0.)

(21) The method according to any one of (1) to (14), wherein the glycolic acid copolymer produced by the method described in (15) is crystallized and solid-phase polymerized at a temperature that maintains a solid state. A method for producing a glycolic acid copolymer according to one of the above.
(22) A molded article obtained from the glycolic acid copolymer according to any one of (1) to (14).

The glycolic acid copolymer of the present invention has high thermal stability at the time of melt molding, has little coloring even at the time of melt molding at a high temperature, and can maintain high quality. Further, a molded product obtained by melt-molding the glycolic acid copolymer of the present invention has high gas barrier properties and high mechanical strength, and has biodegradability. Therefore, for example, it is suitable as a material for sheets, films, multilayer films, injection molded articles, foams, hollow containers, multilayer hollow containers, and various molded articles such as fibers.

As for the molecular weight of the glycolic acid copolymer of the present invention, the weight average molecular weight is 50,000 or more. When the weight average molecular weight is less than 50,000, the practical strength of the stretched film is insufficient. The weight average molecular weight is preferably 80,000 or more, more preferably 100,000 or more, since the strength of a molded product such as an unstretched film or sheet can be sufficiently obtained. The upper limit of the weight average molecular weight is not limited, but is preferably 1,000,000 or less, more preferably 700,000 or less, and most preferably 500,000 or less in consideration of fluidity during molding.
In the present invention, the weight average molecular weight (Mw) of the glycolic acid copolymer is calculated by gel permeation chromatography (GPC) analysis using hexafluoroisopropanol in which 80 mM sodium trifluoroacetate is dissolved as an eluent. Refers to a value. Specifically, using a monodisperse poly (methyl methacrylate) and a methyl methacrylate monomer having a known molecular weight as a standard substance, a calibration curve obtained from the elution time by RI detection is prepared in advance, and the weight average is obtained from the elution time of the glycolic acid copolymer. It is a value obtained by calculating the molecular weight (Mw).

Generally, molecular weights such as weight average molecular weight and number average molecular weight are measured by GPC measurement. However, the molecular weight of a polymer or copolymer containing glycolic acid units in an amount of about 80 mol% or more is determined by using hexafluoroisopropanol in which the polymer or copolymer is soluble as an eluent, and further comprising a monodispersed polymethacrylic acid. When measuring methyl and, if necessary, methyl methacrylate monomer as a standard substance, the molecular weight measurement obtained depends on the presence or absence of sodium trifluoroacetate in the eluent, or the concentration of sodium trifluoroacetate in the eluent. The value fluctuates greatly. Specifically, when GPC measurement is performed using an eluent containing no sodium trifluoroacetate or an eluent containing a small amount of this compound, the measured molecular weight is extremely large or the value is not reproducible. .

The content of glycolic acid units contained in the glycolic acid copolymer of the present invention is from 80 mol% to less than 95 mol%, preferably from 82 mol% to less than 95 mol%, more preferably from 83 mol% to 94 mol%. , Most preferably in the range of 85 mol% to 93 mol%. When the content of the glycolic acid unit is less than 80 mol%, the gas barrier properties of the copolymer are insufficient, and the mechanical properties such as the strength and elastic modulus of the molded product obtained by melt-molding the copolymer. When the physical properties are insufficient and the content of the glycolic acid unit is 95 mol% or more, the thermal stability is remarkably reduced, and coloring at the time of melt molding becomes remarkable.
The glycolic acid copolymer of the present invention contains 5.0 to 20.0 mol% of hydroxycarboxylic acid units other than glycolic acid units, and the average chain length of hydroxycarboxylic acid units other than glycolic acid units is 1%. 0.00 to 1.50, preferably 1.00 to 1.20, more preferably 1.00 to 1.10, further preferably 1.00 to 1.07, and most preferably 1.00 to 1 .05 or less.

When the content of the hydroxycarboxylic acid unit other than the glycolic acid unit is less than 5.0 mol%, the thermal stability of the copolymer is reduced, and the coloring during the melt molding becomes remarkable.
If the average chain length γ exceeds 1.50, it indicates that the copolymer compound is introduced in a block form, and the effect of lowering the melting point of the glycolic acid copolymer by copolymerization is insufficient, so The processability is deteriorated, and further, the gas barrier property of the glycolic acid copolymer is reduced. The minimum value of the average chain length is usually 1.00.
The average chain length of the hydroxycarboxylic acid unit other than the glycolic acid unit is the spectral pattern of the carbonyl group obtained by ¹³ C-NMR measurement under the condition of proton complete decoupling using hexafluoroisopropanol as a solvent and eliminating the nuclear Overhauser effect. Means the average chain length of hydroxycarboxylic acid units other than glycolic acid units (hereinafter, referred to as γ) based on the integrated value calculated from the above.

Specifically, the integral value of the peak of a carbonyl group derived from two chains in which hydroxycarboxylic acid units other than glycolic acid units obtained by the above-described method are adjacent to each other is α, and the hydroxycarboxylic acid unit other than glycolic acid units is α. The integral value of the peak of the carbonyl group derived from the two chains in which the acid unit and the glycolic acid unit are adjacent to each other, and the hydroxycarboxylic acid unit other than the glycolic acid unit and the other unit structure excluding the hydroxycarboxylic acid unit are adjacent to each other. The value γ is calculated by Expression (9), where β is the sum of the integrated values of the peaks of the carbonyl groups derived from the chain.

When two or more hydroxycarboxylic acid units other than the glycolic acid unit are present, two chains in which two or more hydroxycarboxylic acid units other than the glycolic acid unit are adjacent to each other form a hydroxycarboxylic acid unit other than the glycolic acid unit. Is calculated as two chains.
Examples of the hydroxycarboxylic acid unit other than the glycolic acid unit to be copolymerized with the glycolic acid copolymer include an aliphatic monohydroxycarboxylic acid unit other than the glycolic acid unit, an aliphatic polyvalent hydroxymonocarboxylic acid unit, and an aliphatic monohydroxypolycarboxylic acid unit. Polycarboxylic acid unit, aliphatic polyhydroxy polycarboxylic acid unit, aromatic monohydroxy monocarboxylic acid unit, aromatic polyhydroxy monocarboxylic acid unit, aromatic monohydroxy polycarboxylic acid unit, aromatic polyhydroxy It is preferable to use at least one selected from the group consisting of a polyvalent carboxylic acid unit and a hydroxycarboxylic acid unit containing a hetero atom.

Examples of such units include a lactic acid unit, a 2-hydroxybutanoic acid unit, a 2-hydroxypentanoic acid unit, a 2-hydroxyhexanoic acid unit, a 2-hydroxyheptanoic acid unit, and a 2-hydroxyl unit. Octanoic acid unit, 2-hydroxy-2-methylpropanoic acid unit, 2-hydroxy-2-methylbutanoic acid unit, 2-hydroxy-2-ethylbutanoic acid unit, 2-hydroxy-2 -Methylpentanoic acid unit, 2-hydroxy-2-ethylpentanoic acid unit, 2-hydroxy-2-propylpentanoic acid unit, 2-hydroxy-2-butylpentanoic acid unit, 2-hydroxy -2-methylhexano Ic acid unit, 2-hydroxy-2-ethylhexanoic acid unit, 2-hydroxy-2-propylhexanoic acid unit, 2-hydroxy-2-butylhexanoic acid unit, 2-hydroxy-2-pentyl Hexanoic acid unit, 2-hydroxy-2-methylheptanoic acid unit, 2-hydroxy-2-methylheptanoic acid unit, 2-hydroxy-2-ethylheptanoic acid unit, 2-hydroxy-2 -Propyl heptonic acid unit, 2-hydroxy-2-butylheptanoic acid unit, 2-hydroxy-2-pentylheptanoic acid unit, 2-hydroxy-2-hexylheptanoic acid unit, 2-hydroxy- 2-methyloctanoic aqua Acid unit, 2-hydroxy-2-ethyloctanoic acid unit, 2-hydroxy-2-propyloctanoic acid unit, 2-hydroxy-2-butyloctanoic acid unit, 2-hydroxy-2-pentylocta Noic acid unit, 2-hydroxy-2-hexyl octanoic acid unit, 2-hydroxy-2-heptyl octanoic acid unit, 3-hydroxypropanoic acid unit, 3-hydroxybutanoic acid unit, 3 -Hydroxypentanoic acid unit, 3-hydroxyhexanoic acid unit, 3-hydroxyheptanoic acid unit, 3-hydroxyoctanoic acid unit, 3-hydroxy-3-methylbutanoic acid unit, 3- Hydroxy-3- Tylpentanoic acid unit, 3-hydroxy-3-ethylpentanoic acid unit, 3-hydroxy-3-methylhexanoic acid unit, 3-hydroxy-3-ethylhexanoic acid unit, 3-hydroxy- 3-propylhexanoic acid unit, 3-hydroxy-3-methylheptanoic acid unit, 3-hydroxy-3-ethylheptanoic acid unit, 3-hydroxy-3-propylheptanoic acid unit, 3- Hydroxy-3-butylheptanoic acid unit, 3-hydroxy-3-methyloctanoic acid unit, 3-hydroxy-3-ethyloctanoic acid unit, 3-hydroxy-3-propyloctanoic acid unit, 3-hydroxy-3-butylocta Acid unit, 3-hydroxy-3-pentyloctanoic acid unit, 4-hydroxybutanoic acid unit, 4-hydroxypentanoic acid unit, 4-hydroxyhexanoic acid unit, 4-hydroxyheptanoic Acid unit, 4-hydroxyoctanoic acid unit, 4-hydroxy-4-methylpentanoic acid unit, 4-hydroxy-4-methylhexanoic acid unit, 4-hydroxy-4-ethylhexanoic acid unit , 4-hydroxy-4-methylheptanoic acid unit, 4-hydroxy-4-ethylheptanoic acid unit, 4-hydroxy-4-propylheptanoic acid unit, 4-hydroxy-4-methyloctanoic Acid unit 4-hydroxy-4-ethyloctanoic acid units, 4-hydroxy-4-propyloctanoic acid units, 4-hydroxy-4-butyloctanoic acid units, 5-hydroxypentanoic acid units, 5- Hydroxyhexanoic acid unit, 5-hydroxyheptanoic acid unit, 5-hydroxyoctanoic acid unit, 5-hydroxy-5-methylhexanoic acid unit, 5-hydroxy-5-methylheptanoic acid unit , 5-hydroxy-5-ethylheptanoic acid unit, 5-hydroxy-5-methyloctanoic acid unit, 5-hydroxy-5-ethyloctanoic acid unit, 5-hydroxy-5-propyloctanoic Acid unit, 6-hi Roxyhexanoic acid unit, 6-hydroxyheptanoic acid unit, 6-hydroxyoctanoic acid unit, 6-hydroxy-6-methylheptanoic acid unit, 6-hydroxy-6-methyloctanoic acid unit , 6-hydroxy-6-ethyloctanoic acid unit, 7-hydroxyheptanoic acid unit, 7-hydroxyoctanoic acid unit, 7-hydroxy-7-methyloctanoic acid unit, 8-hydroxyoctano Fats such as aliphatic monohydroxymonocarboxylic acid units such as ic acid units, 12-hydroxystearic acid units, 16-hydroxyhexadecanoic acid units, glyceric acid units, arabonic acid units, mannonic acid units, and galactonic acid units Aliphatic polyhydroxy monocarboxylic acid units, malic acid units, aliphatic monohydroxy polycarboxylic acid units such as citric acid units, diglyceric acid units, aliphatic polyhydroxy polycarboxylic acid units such as mannosaccharic acid units, Aromatic monohydroxymonocarboxylic acid units such as hydroxybenzoic acid units, 2,3-dihydroxybenzoic acid units, 2,4-dihydroxybenzoic acid units, 2,5-dihydroxybenzoic acid units, 2,6-dihydroxybenzoic acid units Aromatic polyhydroxy monocarboxylic acid units such as 3,4-dihydroxybenzoic acid unit and 3,5-dihydroxybenzoic acid unit, and aromatic monohydroxy polyfunctional units such as 4-hydroxyisophthalic acid unit and 5-hydroxyisophthalic acid unit Aromatic polyvalent hydroxyl groups such as polyvalent carboxylic acid units and 2,5-dihydroxyterephthalic acid units; Carboxylic acid units, and the like.

Furthermore, a hydroxycarboxylic acid unit containing a hetero atom, for example, a 2-hydroxyethoxyacetic acid unit, a 2-hydroxypropoxyacetic acid unit and the like can be mentioned. Among them, D-form, L-form or a mixture thereof can be used for those having an asymmetric carbon in the unit structure. These can be used alone or in combination of two or more.
Of these, monohydroxymonocarboxylic acid units are preferred because they suppress the increase in water absorption, reduce the rate of hydrolysis, or are excellent in processability such as stretchability, and provide a molded article having flexibility. Is used, and more preferably, an aliphatic monohydroxymonocarboxylic acid unit, more preferably, a lactic acid unit, a 3-hydroxybutyric acid unit, a 4-hydroxybutyric acid unit, a 3-hydroxyvaleric acid unit, 6- A hydroxyhexanoic acid unit, a 12-hydroxystearic acid unit, a 16-hydroxyhexadecanoic acid unit, or a mixed unit thereof is used. From the viewpoint of easy availability of raw materials, a lactic acid unit and a 6-hydroxyhexanoic acid unit are more preferable. Hydroxyhexanoic acid units or a mixture of these units is used. Mashiku the lactic acid units is used.

The diglycolic acid unit content of the glycolic acid copolymer of the present invention is 0 or 0.10 mol% or less, preferably more than 0 and 0.10 mol% or less, more preferably more than 0 and 0.09 mol% or less. Most preferably, it is in the range of 0.01 to 0.08 mol%.
When the content of the diglycolic acid unit in the copolymer exceeds 0.10 mol%, the heat stability or heat aging resistance of the resin during molding decreases. When a glycolic acid copolymer is obtained by polycondensation using glycolic acid and / or a derivative thereof and a compound copolymerizable with glycolic acid and / or a derivative thereof as a starting material, the dicondensation usually occurs in the course of the polycondensation reaction. Glycolic acid units are formed. Therefore, the content of the diglycolic acid unit in the glycolic acid copolymer is usually a value exceeding 0.

In the present invention, the content of diglycolic acid units in the glycolic acid copolymer is determined using a high performance liquid chromatography (HPLC) analyzer under the following conditions.
That is, after pulverization, 5 g of a glycolic acid copolymer dried at 80 ° C. for 6 hours under vacuum conditions is weighed, hydrolyzed at room temperature with 10 ml of 8N-NaOH aqueous solution for 48 hours, and then with 12.5 ml of concentrated hydrochloric acid aqueous solution. An aqueous solution under acidic conditions is used as a sample solution. A sample aqueous solution was prepared using a 0.75% by mass aqueous phosphoric acid solution as an eluent under the conditions of a column temperature of 40 ° C. and an eluent flow rate of 1 ml / min (column configuration: RSpak® KC manufactured by Showa Denko KK). -811 connected in series), and the absorbance of the peak corresponding to the corresponding diglycolic acid detected by a UV detector (wavelength 210 nm) was measured. Is a value obtained by calculating the content of diglycolic acid units present in the dried and weighed resin as mol% using the calibration curve of

In the glycolic acid copolymer of the present invention, a glycolic acid unit, other than a hydroxycarboxylic acid unit and a diglycolic acid unit other than the glycolic acid unit, and as other copolymerized units, an amount of a polyol unit which does not deviate from the present invention. And / or polycarboxylic acid units other than diglycolic acid units can be copolymerized.
In the present invention, unless otherwise specified, the polycarboxylic acid unit may contain a diglycolic acid unit.

The polyol unit used as the copolymer unit of the present invention contains two or more hydroxyl groups, and preferably has 2 to 20 carbon atoms. When the glycolic acid copolymer is composed of (a) a glycolic acid unit, (b) a hydroxycarboxylic acid unit other than glycolic acid, (c) a diglycolic acid unit, and (d) a polyol unit, the amount of the polyol unit is as follows. The total amount of (a), (b), (c) and (d) is preferably more than 0 and 0.25 mol% or less, more preferably 0.02 mol% or more and 0.20 mol% or less. More preferably, it is. Examples of such polyol units include ethylene glycol units, 1,3-propanediol units, 1,2-propanediol units, 1,4-butanediol units, 2,3-butanediol units, and 1,5-pentane. Diol unit, 1,6-hexanediol unit, 1,7-heptanediol unit, 1,8-octanediol unit, 1,9-nonanediol unit, 1,10-decanediol unit, 1,12-dodecanediol unit 1,4-cyclohexanediol unit, 1,2-cyclohexanediol unit, 1,3-cyclohexanediol unit, aliphatic diol unit such as neopentyl glycol unit, bisphenol A unit, catechol unit, resorcinol unit, 1,2- Benzenedimethanol unit, 1,3-benzenedimethanol Unit, aromatic diol unit such as 1,4-benzenedimethanol unit, and further, a diol unit containing a hetero atom, for example, diethylene glycol unit, triethylene glycol unit, tetraethylene glycol unit, and the like, further glycerin unit, 1, Aliphatic triol units such as 2,4-butanetriol unit, trimethylolethane unit, trimethylolpropane unit, butane-1,2,3-triol unit, 1,2,4-benzenetriol unit, 1,3,5 -Aromatic triol units such as benzenetriol units, starch units, glucose units, cellulose units, hemicellulose units, xylose units, arabinose units, mannose units, galactose units, xylitol units, arabinitol units, mannitol units, galactitol units Pentaerythritol unit, chitin units, chitosan units, dextrin units, dextran units, carboxymethylcellulose units, amylopectin units, and saccharides units such as glycogen units. These can be used alone or in combination of two or more. In the case of a compound having an asymmetric carbon atom and having an optical isomer, any of them can be used.

Among these, in consideration of thermal stability at the time of melt molding or heat aging resistance, the diol unit is a compound unit having 3 or more carbon atoms, for example, 1,3-propanediol unit, 1,2-propanediol. Unit, 1,4-butanediol unit, 2,3-butanediol unit, 1,5-pentanediol unit, 1,6-hexanediol unit, 1,7-heptanediol unit, 1,8-octanediol unit, 1,9-nonanediol unit, 1,10-decanediol unit, 1,12-dodecanediol unit, 1,4-cyclohexanediol unit, 1,2-cyclohexanediol unit, 1,3-cyclohexanediol unit, neopentyl Aliphatic diol units such as glycol units, bisphenol A units, catechol units, resorcinol units , 1,2-benzenedimethanol unit, 1,3-benzene dimethanol units, aromatic diol units such as 1,4-benzene dimethanol units, more preferably used.

From the viewpoint of obtaining a molded article having flexibility in addition to heat stability at the time of melt molding or heat aging resistance, more preferably 1,3-propanediol unit, 1,2-propanediol unit, 4-butanediol unit, 2,3-butanediol unit, 1,5-pentanediol unit, 1,6-hexanediol unit, 1,7-heptanediol unit, 1,8-octanediol unit, 1,9- Nonanediol units, 1,10-decanediol units, 1,12-dodecanediol units, 1,4-cyclohexanediol units, 1,2-cyclohexanediol units, 1,3-cyclohexanediol units, neopentyl glycol units, etc. Aliphatic diol units are used.

The unit having three or more hydroxyl groups in one molecule is contained to increase the melt tension of the copolymer, and in order to stably exhibit the effect, a compound unit having 4 or more carbon atoms, for example, 1, Aliphatic triol units such as 2,4-butanetriol unit, trimethylolethane unit, trimethylolpropane unit, butane-1,2,3-triol unit, 1,2,4-benzenetriol unit, 1,3,5 -Saccharide units such as aromatic triol units such as benzenetriol units, xylitol units, arabinitol units, mannitol units, galactitol units and pentaerythritol units are more preferably used.
Of these polyol units, more preferably a polyol unit having 5 or more carbon atoms and having 2 or 3 hydroxyl groups in one molecule, for example, 1,5-pentanediol unit, 1,6-hexanediol Unit, 1,7-heptanediol unit, 1,8-octanediol unit, 1,9-nonanediol unit, 1,10-decanediol unit, 1,12-dodecanediol unit, 1,4-cyclohexanediol unit, Aliphatic diol units such as 1,2-cyclohexanediol unit, 1,3-cyclohexanediol unit and neopentyl glycol unit, and aliphatic triol units such as trimethylolethane unit and trimethylolpropane unit are used. Of these polyol units, most preferably, a neopentyl glycol unit is used.

In the glycolic acid copolymer of the present invention, glycolic acid units, in addition to hydroxycarboxylic acid units and diglycolic acid units other than glycolic acid units, as other copolymerized units, an amount of a range not departing from the scope of the present invention. It is also possible to copolymerize a polycarboxylic acid unit other than the diglycolic acid unit.
Polycarboxylic acid units other than diglycolic acid units used as other copolymerized units are those containing two or more carboxyl groups, and polycarboxylic acid units other than diglycolic acid units having 2 to 20 carbon atoms are preferred. . When the glycolic acid copolymer comprises (a) glycolic acid units, (b) hydroxycarboxylic acid units other than glycolic acid, (c) diglycolic acid units, and (e) polycarboxylic acid units other than diglycolic acid units The amount of the polycarboxylic acid unit other than the diglycolic acid unit is more than 0 and 0.15 mol% or less based on the total amount of the above (a), (b), (c) and (e). Is more preferable, and more preferably more than 0 and 0.10 mol% or less.

As such a polycarboxylic acid unit other than the diglycolic acid unit, for example, oxalic acid unit, malonic acid unit, glutaric acid unit, succinic acid unit, adipic acid unit, pimelic acid unit, suberic acid unit, azelaic acid unit, sebacin unit Acid units, undecandioic acid units, dodecandioic acid units, fumaric acid units, maleic acid units, aliphatic dicarboxylic acid units such as 1,4-cyclohexanedicarboxylic acid units, phthalic acid units, isophthalic acid units, terephthalic acid units, etc. An aromatic dicarboxylic acid unit, a propanetricarboxylic acid unit, a trimellitic acid unit, a pyromellitic acid unit, an aliphatic tricarboxylic acid unit such as a 1,3,6-hexanetricarboxylic acid unit, a 1,2,3-benzenetricarboxylic acid unit, 1,2,4-benzenetricarboxylic acid unit, 1,3,5-benzenetricarbo Aromatic tricarboxylic acid units, such as acid units, carboxylic acid units, such as a carboxyl group in one molecule, such as ethylenediaminetetraacetic acid units are contained 4 or more can be mentioned. These can be used alone or in combination of two or more.

Of these polycarboxylic acid units, more preferably, oxalic acid units, malonic acid units, glutaric acid units, succinic acid units, adipic acid units, pimelic acid units, suberic acid units, azelaic acid units, sebacic acid units, undecane Aliphatic dicarboxylic acid units such as diacid units, dodecane diacid units, 1,4-cyclohexanedicarboxylic acid units, phthalic acid units, isophthalic acid units, terephthalic acid units and other aromatic dicarboxylic acid units, propanetricarboxylic acid units, Aliphatic tricarboxylic acid units such as melitic acid unit, pyromellitic acid unit, 1,3,6-hexanetricarboxylic acid unit, 1,2,3-benzenetricarboxylic acid unit, 1,2,4-benzenetricarboxylic acid unit, 1 And aromatic tricarboxylic acid units such as 3,3,5-benzenetricarboxylic acid unit.

Most preferably, since a molded article having flexibility is obtained, oxalic acid units, malonic acid units, glutaric acid units, succinic acid units, adipic acid units, pimelic acid units, suberic acid units, azelaic acid units, sebacic acid, Unit, undecandioic acid unit, dodecandioic acid unit, aliphatic dicarboxylic acid unit such as 1,4-cyclohexanedicarboxylic acid unit, propanetricarboxylic acid unit, trimellitic acid unit, pyromellitic acid unit, 1,3,6-hexane An aliphatic tricarboxylic acid unit such as a tricarboxylic acid unit is used.

単 位 Furthermore, it is also possible to introduce units other than the copolymerized units exemplified so far as long as the effects of the present invention are not impaired. Examples of such a copolymerized unit include a glycine unit, a (+)-alanine unit, a β-alanine unit, a (-)-asparagine unit, a (+)-aspartic acid unit, a (-)-cysteine unit and a (+) ) -Glutamine sun unit, (+)-glutamine unit, (−)-hydroxylysine unit, (−)-leucine unit, (+)-isoleucine unit, (+)-lysine unit, (−)-methionine unit, -)-Serine unit, (-)-threonine unit, (+)-valine unit, aminobutyric acid unit, azaserine unit, arginine unit, amino acid unit such as ethionine unit, for example, hydrazine unit, methylhydrazine unit, monomethylenediamine unit , Dimethylene diamine unit, trimethylene diamine unit, tetramethylene diamine unit, pentamethylene diamine unit, Polyamine units such as samethylenediamine unit, heptamethylenediamine unit, octamethylenediamine unit, nonamethylenediamine unit, decamethylenediamine unit, undecamethylenediamine unit, dodecamethylenediamine unit, for example, propane lactam unit, α- Pyrrolidone unit, α-piperidone unit, ε-caprolactam unit, α-methyl-caprolactam unit, β-methyl-caprolactam unit, γ-methyl-caprolactam unit, δ-methyl-caprolactam unit, ε-methyl-caprolactam unit, N- Methyl-caprolactam unit, β, γ-dimethyl-caprolactam unit, γ-ethyl-caprolactam unit, γ-isopropyl-caprolactam unit, ε-isopropyl-caprolactam unit, γ-butyl-caprolactam unit, γ- Kisa cyclo benzyl - caprolactam unit, .omega. enantholactam units, .omega. capryl lactam unit, caprylolactone lactam unit, lactam units such laurolactam units, and the like. These can be used alone or in combination of two or more. In the case of a compound having an asymmetric carbon atom and having an optical isomer, any of them can be used.

Further, as long as the effects of the present invention are not impaired, a known unit structure may contain a compound unit having two or more isocyanate groups and / or epoxy groups.
The glycolic acid copolymer of the present invention includes, among the unit structures listed above, (I) a glycolic acid copolymer comprising a glycolic acid unit, a hydroxycarboxylic acid unit other than the glycolic acid unit, and a polyol unit And (II) a glycolic acid copolymer composed of glycolic acid units, hydroxycarboxylic acid units other than glycolic acid units, polyol units, and polycarboxylic acid units other than diglycolic acid units. The glycolic acid copolymer (I) or (II) may further contain a diglycolic acid unit, but it is more preferably 0 or as little as possible. In the cases of the above (I) and (II), the hydrolysis resistance tends to be improved, or the obtained molded article tends to have flexibility.

When having a polyol unit as the unit structure of the glycolic acid copolymer, the amount of the polyol unit, the amount of the diglycolic acid unit introduced into the glycolic acid copolymer, and, if necessary, as the unit structure In consideration of the amount of polycarboxylic acid units other than the diglycolic acid unit to be introduced, the difference between the total amount of each hydroxyl group and the total amount of carboxyl groups is preferably 0.10 mol% or less. , 0.04 mol% or less, and most preferably the total amount of each hydroxyl group and the total amount of carboxyl groups are substantially equivalent.
In the glycolic acid copolymer of the present invention, the content of the polyol unit and / or the polycarboxylic acid unit in the cases (I) and (II) is such that the total content of the polyol unit and the polycarboxylic acid unit is 2 mol. % Is preferred. If the total content of the polyol unit and the polycarboxylic acid unit exceeds 2.0 mol%, the gas barrier properties of the glycolic acid copolymer may be reduced.

In the cases (I) and (II), the content of the polyol unit and / or the polycarboxylic acid unit is such that the total content of the polyol unit and the polycarboxylic acid unit exceeds 0.02 mol% and is 2.0 mol%. When the content is less than 0.02 mol% and less than 2.0 mol%, the hydrolysis resistance is improved, and therefore it is more preferable.
In the case of the above (I) and (II), one unit structure such as a polyvalent hydroxy monocarboxylic acid unit, a monohydroxy polyvalent carboxylic acid unit, a polyvalent hydroxy polycarboxylic acid unit, a polyol unit, a polycarboxylic acid unit, etc. It is possible to include a compound unit having a total amount of 3 or more hydroxyl groups and / or carboxyl groups therein, and the content of the compound unit having a total amount of 3 or more hydroxyl groups and / or carboxyl groups in the one unit structure. In consideration of workability such as stretchability, the total of is preferably 0.07 mol% or less, more preferably 0.05 mol% or less, still more preferably 0.03 mol% or less, and 0.02 mol% or less. Most preferred.

Although the terminal molecular structure of the glycolic acid copolymer of the present invention is not limited, examples thereof include a hydroxyl group, a carboxyl group, an acyl group, an alkyl group, an aryl group, and an alkoxy group.
Next, an example of the method for producing the glycolic acid copolymer of the present invention will be described, but the method for producing the copolymer of the present invention is not limited thereto.
The glycolic acid copolymer of the present invention comprises glycolic acid and / or a derivative thereof, and a compound copolymerizable with the glycolic acid and / or a derivative thereof, including a hydroxycarboxylic acid other than glycolic acid and / or a derivative thereof. A glycolic acid copolymer can be produced by polycondensation including the following [Steps (A), (B) and (C)] using a raw material consisting of
(A) A step of producing a glycolic acid copolymer having a weight-average molecular weight of 700 to 5,000 by performing a polycondensation reaction at a reaction temperature of 20 ° C to 160 ° C [Step (A)] ].
(B) Following [Step (A)], a step of raising the reaction temperature to 190 ° C. within 100 minutes [Step (B)].
(C) When producing a glycolic acid copolymer having a weight average molecular weight of 10,000 or more by performing a polycondensation reaction at a reaction temperature in a range of 190 ° C. or more and 300 ° C. or less following [Step (B)]. Subjecting the glycolic acid copolymer to a polycondensation reaction under the condition that the weight-average molecular weight increases until the weight-average molecular weight reaches 10,000 or more per hour [step (C)] ].

Hereinafter, the raw materials used in the present invention will be described.
In the present invention, glycolic acid used as a raw material is a monomer of glycolic acid or an oligomer thereof. The weight average molecular weight of the oligomer is less than 700 when determined by the same method as the method for measuring the weight average molecular weight of the glycolic acid copolymer in the present invention. Therefore, in the present invention, at least one selected from glycolic acid, glycolic acid oligomers, glycolic acid derivatives and derivatives of glycolic acid oligomers can be used as a raw material.
As a derivative of glycolic acid used as a raw material, the glycolic acid described above and an alcohol having 1 to 10 carbon atoms, for example, methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, cyclohexanol, octanol and the like can be used. Esters and glycolide, which is a cyclic dimer ester of glycolic acid, are exemplified.

Glycolic acid and / or a derivative thereof may be used alone or in combination of two or more.
The hydroxycarboxylic acid other than glycolic acid used as a raw material in the present invention is a monomer of a hydroxycarboxylic acid other than glycolic acid or an oligomer thereof. The weight average molecular weight of the oligomer is less than 700 when determined by the same method as the method for measuring the weight average molecular weight of the glycolic acid copolymer in the present invention. Therefore, in the present invention, as a raw material, at least one selected from hydroxycarboxylic acids other than glycolic acid, hydroxycarboxylic acid oligomers other than glycolic acid, hydroxycarboxylic acid derivatives other than glycolic acid, and hydroxycarboxylic acid oligomer derivatives other than glycolic acid. One type can be used.

Examples of the hydroxycarboxylic acids other than glycolic acid copolymerized with the glycolic acid copolymer include aliphatic monohydroxycarboxylic acids other than glycolic acid, aliphatic polyhydroxyhydroxycarboxylic acids, aliphatic monohydroxypolycarboxylic acids, and fatty acids. Containing aromatic polyhydroxy polycarboxylic acids, aromatic monohydroxy monocarboxylic acids, aromatic polyhydroxy monocarboxylic acids, aromatic monohydroxy polycarboxylic acids, aromatic polyhydroxy polycarboxylic acids, and heteroatoms It is preferable to use at least one selected from the group consisting of hydroxycarboxylic acids.

Such compounds include, for example, lactic acid, 2-hydroxybutanoic acid, 2-hydroxypentanoic acid, 2-hydroxyhexanoic acid, 2-hydroxyheptanoic acid, 2-hydroxyoctanoic acid 2-hydroxy-2-methylpropanoic acid, 2-hydroxy-2-methylbutanoic acid, 2-hydroxy-2-ethylbutanoic acid, 2-hydroxy-2-methylpentanoic acid, -Hydroxy-2-ethylpentanoic acid, 2-hydroxy-2-propylpentanoic acid, 2-hydroxy-2-butylpentanoic acid, 2-hydroxy-2-methylhexanoic acid, 2-hydroxy -2-ethylhexyl Neuic acid, 2-hydroxy-2-propylhexanoic acid, 2-hydroxy-2-butylhexanoic acid, 2-hydroxy-2-pentylhexanoic acid, 2-hydroxy-2-methylheptanoic Acid, 2-hydroxy-2-methylheptanoic acid, 2-hydroxy-2-ethylheptanoic acid, 2-hydroxy-2-propylheptanoic acid, 2-hydroxy-2-butylheptanoic acid, 2 -Hydroxy-2-pentylheptanoic acid, 2-hydroxy-2-hexylheptanoic acid, 2-hydroxy-2-methyloctanoic acid, 2-hydroxy-2-ethyloctanoic acid, 2-hydroxy -2-propyloctanoy Acid, 2-hydroxy-2-butyloctanoic acid, 2-hydroxy-2-pentyloctanoic acid, 2-hydroxy-2-hexyloctanoic acid, 2-hydroxy-2-heptyloctanoic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 3-hydroxypentanoic acid, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 3- Hydroxy-3-methylbutanoic acid, 3-hydroxy-3-methylpentanoic acid, 3-hydroxy-3-ethylpentanoic acid, 3-hydroxy-3-methylhexanoic acid, 3-hydroxy- 3-d Lehexanoic acid, 3-hydroxy-3-propylhexanoic acid, 3-hydroxy-3-methylheptanoic acid, 3-hydroxy-3-ethylheptanoic acid, 3-hydroxy-3-propylhepta Neuic acid, 3-hydroxy-3-butylheptanoic acid, 3-hydroxy-3-methyloctanoic acid, 3-hydroxy-3-ethyloctanoic acid, 3-hydroxy-3-propyloctanoic Acid, 3-hydroxy-3-butyloctanoic acid, 3-hydroxy-3-pentyloctanoic acid, 4-hydroxybutanoic acid, 4-hydroxypentanoic acid, 4-hydroxyhexanoic acid, 4-hydroxy Tanoic acid, 4-hydroxyoctanoic acid, 4-hydroxy-4-methylpentanoic acid, 4-hydroxy-4-methylhexanoic acid, 4-hydroxy-4-ethylhexanoic acid, 4- Hydroxy-4-methylheptanoic acid, 4-hydroxy-4-ethylheptanoic acid, 4-hydroxy-4-propylheptanoic acid, 4-hydroxy-4-methyloctanoic acid, 4-hydroxy- 4-ethyloctanoic acid, 4-hydroxy-4-propyloctanoic acid, 4-hydroxy-4-butyloctanoic acid, 5-hydroxypentanoic acid, 5-hydroxyhexanoic acid, 5- Hydroxyheptanoit Acid, 5-hydroxyoctanoic acid, 5-hydroxy-5-methylhexanoic acid, 5-hydroxy-5-methylheptanoic acid, 5-hydroxy-5-ethylheptanoic acid, 5-hydroxy- 5-methyloctanoic acid, 5-hydroxy-5-ethyloctanoic acid, 5-hydroxy-5-propyloctanoic acid, 6-hydroxyhexanoic acid, 6-hydroxyheptanoic acid, 6-hydroxyoctanoic acid, 6-hydroxy-6-methylheptanoic acid, 6-hydroxy-6-methyloctanoic acid, 6-hydroxy-6-ethyloctanoic acid, 7-hydroxyheptanoic Acid, 7-hydroxy Aliphatic monohydroxymonocarboxylic acids such as octanoic acid, 7-hydroxy-7-methyloctanoic acid, 8-hydroxyoctanoic acid, 12-hydroxystearic acid, 16-hydroxyhexadecanoic acid, Aromatic monohydroxymonocarboxylic acids such as hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxy Aromatic polyhydroxy monocarboxylic acids such as benzoic acid and 3,5-dihydroxybenzoic acid; aromatic monohydroxy polycarboxylic acids such as 4-hydroxyisophthalic acid and 5-hydroxyisophthalic acid; and 2,5-dihydroxy terephthalic acid Aromatic polyvalent hydroxy polyvalent Aliphatic polyhydroxy monocarboxylic acids such as boric acid, glyceric acid, arabonic acid, mannonic acid, and galactonic acid; malic acid; aliphatic monohydroxy polycarboxylic acids such as citric acid; diglyceric acid; And polyhydric hydroxy polycarboxylic acids.

Furthermore, hydroxycarboxylic acids containing a hetero atom, for example, 2-hydroxyethoxyacetic acid, 2-hydroxypropoxyacetic acid and the like can be mentioned.
Lactones such as β-propiolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone can also be mentioned.
These may be used alone or as a mixture of two or more. Any of compounds having an asymmetric carbon atom in the unit structure and having an optical isomer can be used.
Examples of the hydroxycarboxylic acid derivatives other than glycolic acid include the above hydroxycarboxylic acids and monofunctional alcohols having 1 to 10 carbon atoms, for example, methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, octanol and the like. Examples include esters, cyclic dimer esters of hydroxycarboxylic acids other than glycolic acid such as lactide, and cyclic dimer esters of glycolic acid and hydroxycarboxylic acids other than glycolic acid. These may be used alone or in combination of two or more.

Among them, it is preferable to use monohydroxymonocarboxylic acid and monohydroxymonocarboxylic acid, since the increase in water absorption is suppressed, the hydrolysis rate is reduced, or excellent processability such as stretchability is obtained, and a molded article having flexibility is obtained. / Or a derivative thereof, or a mixture thereof is used, more preferably, an aliphatic monohydroxymonocarboxylic acid and / or a derivative thereof, or a mixture thereof is used. More preferably, lactic acid, lactide, glycolic acid, and lactic acid are used. Cyclic dimer ester, 3-hydroxybutyric acid and / or β-propiolactone, 4-hydroxybutyric acid and / or γ-butyrolactone, 3-hydroxyvaleric acid, 6-hydroxyhexanoic acid And / or ε-caprolactone, 12-hydroxystearic acid, 16 Hydroxyhexadecanoic acid or a derivative of the above-mentioned aliphatic hydroxycarboxylic acid, or a mixture of the above-mentioned compounds is used. Particularly, lactic acid, lactide, a cyclic dimer composed of glycolic acid and lactic acid is particularly preferable in terms of availability of raw materials. Ester, 6-hydroxyhexanoic acid and / or ε-caprolactone or a derivative of the above-mentioned aliphatic hydroxycarboxylic acid, or a mixture of the above-mentioned compounds is used, and most preferably, lactic acid, lactide, a cyclic mixture of glycolic acid and lactic acid A dimer ester or a derivative of lactic acid, or a mixture of the above compounds is used.

In the present invention, as a compound copolymerizable with glycolic acid and / or a derivative thereof and a hydroxycarboxylic acid other than glycolic acid and / or a derivative thereof, a polyol or polycarboxylic acid in an amount not departing from the scope of the present invention is used. And / or a compound such as a derivative thereof can be used as a raw material.
Examples of such a polyol include compounds containing two or more hydroxyl groups, and a polyol having 2 to 20 carbon atoms is preferable. Such polyols include, for example, ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6- Hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, 1,2-cyclohexane Aliphatic diols such as diol, 1,3-cyclohexanediol, neopentyl glycol, bisphenol A, catechol, resorcinol, 1,2-benzenedimethanol, 1,3-benzenedimethanol, 1,4-benzenedimethanol, etc. Aromatic diols and also diols containing heteroatoms, such as , Diethylene glycol, triethylene glycol, tetraethylene glycol, and the like, and glycerin, 1,2,4-butanetriol, trimethylolethane, trimethylolpropane, butane-1,2,3-triol and the like. 2,2,4-benzenetriol, aromatic triols such as 1,3,5-benzenetriol, starch, glucose, cellulose, hemicellulose, xylose, arabinose, mannose, galactose, xylitol, arabinitol, mannitol, galactitol, pentaerythritol, Examples include saccharides such as chitin, chitosan, dextrin, dextran, carboxymethylcellulose, amylopectin, and glycogen.

These can be used alone or in combination of two or more. Among these, any of the compounds having an asymmetric carbon atom in the molecule and having an optical isomer can be used.
Among these, suppressing side reactions during polycondensation, or considering the thermal decomposition property during melt molding of the obtained copolymer, or heat aging resistance, the polyol is a diol having 3 or more carbon atoms, for example, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, neopentyl Aliphatic diols such as glycol, bisphenol A, catechol, resorcinol, 1,2-benzenedimethanol, , 3-benzene dimethanol, aromatic diols such as 1,4-benzene dimethanol, more preferably used.

From the viewpoint of obtaining a molded article having flexibility in addition to heat stability at the time of melt molding or heat aging resistance, more preferably, for example, 1,3-propanediol, 1,2-propanediol, 4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10 Aliphatic diols such as -decanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, and neopentyl glycol are used.
On the other hand, a polyol having three or more hydroxyl groups in one molecule is used to increase the melt tension of the copolymer. In order to stably exhibit the effect, a compound having four or more carbon atoms, for example, Aliphatic triols such as 1,2,4-butanetriol, trimethylolethane, trimethylolpropane, butane-1,2,3-triol, 1,2,4-benzenetriol, 1,3,5-benzenetriol and the like And sugars such as aromatic triol, glucose, xylose, arabinose, mannose, galactose, xylitol, arabinitol, mannitol, galactitol, and pentaerythritol.

Among these polyols, more preferably, polyols having 5 or more carbon atoms and having 3 or less hydroxyl groups in one molecule, for example, 1,5-pentanediol, 1,6-hexanediol, 1,7 -Heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, 1,3- Aliphatic diols such as cyclohexanediol and neopentyl glycol, and aliphatic triols such as trimethylolethane and trimethylolpropane are used.
Of these, neopentyl glycol is particularly preferably used.

The compound used as the copolymerizable polycarboxylic acid includes a compound having two or more carboxyl groups, and a polycarboxylic acid having 2 to 20 carbon atoms is preferable. Such polycarboxylic acids include, for example, oxalic acid, malonic acid, glutaric acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, fumaric acid, maleic acid , Diglycolic acid, aliphatic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, aromatic dicarboxylic acids such as terephthalic acid, propanetricarboxylic acid, trimellitic acid, pyromellitic acid, 1,3 Aliphatic tricarboxylic acids such as 6-hexanetricarboxylic acid, aromatic tricarboxylic acids such as 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, ethylenediaminetetracarboxylic acid; Examples thereof include tetracarboxylic acids such as acetic acid. These can be used alone or in combination of two or more.

Examples of the polycarboxylic acid derivative include an ester of the corresponding polycarboxylic acid and a monofunctional alcohol having 1 to 10 carbon atoms, for example, methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, octanol, and the like. Esters with acids, and corresponding derivatives such as polycarboxylic anhydrides, and the like.
Of these polycarboxylic acids, more preferably, oxalic acid, malonic acid, glutaric acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, diglycolic acid Dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and / or derivatives thereof, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid and / or derivatives thereof, propanetricarboxylic acid, trimellitic acid, pyromellitic Acids, aliphatic tricarboxylic acids such as 1,3,6-hexanetricarboxylic acid and / or derivatives thereof, 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,3,5-benzene Aromatic tricarboxylic acids such as tricarboxylic acids and / or derivatives thereof are used.

Particularly preferably, since a molded article having flexibility is obtained, oxalic acid, malonic acid, glutaric acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid , Aliphatic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and / or derivatives thereof, and aliphatic tricarboxylic acids such as propanetricarboxylic acid, trimellitic acid, pyromellitic acid, and 1,3,6-hexanetricarboxylic acid, and / or Its derivatives are used.
In addition, for example, amino acids, polyvalent amines, lactams, and the like can be used as a copolymer component within a range that does not impair the effects of the present invention.

As the amino acid, an amino acid having 2 to 20 carbon atoms is preferable. Examples of the amino acid include glycine, (+)-alanine, β-alanine, (−)-asparagine, (+)-aspartic acid, (−)-cysteine, (+)-glutaminesan, (+)-glutamine, and (+)-glutamine. -)-Hydroxylysine, (-)-leucine, (+)-isoleucine, (+)-lysine, (-)-methionine, (-)-serine, (-)-threonine, (+)-valine, aminobutyric acid , Azaserine, arginine, ethionine and the like.
As the polyamine, a polyamine having 0 to 20 carbon atoms is preferable. As the amine, for example, monomethylene diamine, dimethylene diamine, trimethylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, heptamethylene diamine, octamethylene diamine, nonamethylene diamine, decamethylene diamine, undecamethylene diamine, Dodecamethylenediamine and the like.

As the lactam, a lactam having 2 to 20 carbon atoms is preferable. Examples of lactams include glycine anhydride, propane lactam, α-pyrrolidone, α-piperidone, ε-caprolactam, α-methyl-caprolactam, β-methyl-caprolactam, γ-methyl-caprolactam, δ-methyl-caprolactam, ε- Methyl-caprolactam, N-methyl-caprolactam, β, γ-dimethyl-caprolactam, γ-ethyl-caprolactam, γ-isopropyl-caprolactam, ε-isopropyl-caprolactam, γ-butyl-caprolactam, γ-hexacyclobenzyl-caprolactam, ω-enantholactam, ω-caprylactam, capryloractam, laurolactam, dimer of caprolactone and the like.

Among the above compounds, those having an asymmetric carbon atom and in which a D-form, an L-form, and a D / L mixture can exist, any of them can be used.
The form of glycolic acid and / or a derivative thereof, and a compound copolymerizable with glycolic acid and / or a derivative thereof is not limited, and a solution such as an aqueous solution, a crystal, a liquid, or the like can be used. . When a solution of these compounds is used, the concentration of the compounds is not limited, but is preferably 40% by mass or more, more preferably 50% by mass or more, and most preferably 60% by mass or more.
Here, the “compound unit” and the “converted molar ratio” of the raw materials used in [Step (A)] of the method for producing a glycolic acid copolymer of the present invention will be described.

In the present invention, the “compound unit” represents a minimum constituent unit obtained by hydrolyzing a compound constituting a raw material. Specifically, a glycolic acid unit, a hydroxycarboxylic acid unit other than glycolic acid, a polycarboxylic acid unit, and a polyol unit will be described below.
In the case of glycolic acid and / or its derivative, the glycolic acid unit contained in glycolic acid and / or its derivative means a unit structure represented by chemical formula (2) in glycolic acid and / or its derivative.

When a hydroxycarboxylic acid other than glycolic acid or a derivative thereof, for example, lactic acid and / or a derivative thereof is exemplified, a lactic acid unit contained in lactic acid and / or a derivative thereof is represented by the chemical formula (3) in the lactic acid and / or a derivative thereof. Represents a unit structure represented by

When polycarboxylic acid or a derivative thereof, for example, adipic acid and / or a derivative thereof is exemplified, the adipic acid unit contained in adipic acid and / or a derivative thereof is represented by the chemical formula (4) in adipic acid and / or a derivative thereof. Represents a unit structure represented by

When a polyol, for example, neopentyl glycol is exemplified, the neopentyl glycol unit indicates a unit structure represented by the chemical formula (5).

The “converted molar ratio” in the present invention is a value obtained by individually calculating the number of moles of the unit structure with respect to each raw material compound and expressing the ratio of the number of moles of the unit structure of each raw material compound to the total. In the calculation of the molar ratio, among the raw material compounds, for a compound having a molar ratio of the unit structure of less than 0.00005, the number of moles of the unit structure of the compound is set to zero.
The sum of the number of moles of the unit structure of the raw material compound which is individually calculated and used for calculating the reduced molar ratio includes the monofunctional alcohols, monofunctional carboxylic acids, etc. The compound content is not included. That is, for example, when a monofunctional alcohol having 1 to 10 carbon atoms or an ester with a monofunctional carboxylic acid is used as a raw material, the alcohol or carboxylic acid is released by hydrolysis or the like, and the raw material is released. However, such monofunctional alcohols and monofunctional carboxylic acids are not considered when calculating the reduced molar ratio.

In the present invention, in a raw material comprising glycolic acid and / or a derivative thereof and a compound copolymerizable with the glycolic acid and / or a derivative thereof, including a hydroxycarboxylic acid other than glycolic acid and / or a derivative thereof, The reduced molar ratio of diglycolic acid units needs to be less than 0.001. When the molar ratio of diglycolic acid units exceeds 0.001, the glycolic acid copolymer of the present invention cannot be obtained. Preferably it is less than 0.0005, more preferably less than 0.0003.
A raw material comprising glycolic acid and / or a derivative thereof and a compound copolymerizable with the glycolic acid and / or a derivative thereof, including a hydroxycarboxylic acid other than glycolic acid and / or a derivative thereof, is subjected to polymerization under melting conditions. When a glycolic acid copolymer is produced by condensation, a diglycolic acid unit is formed by a side reaction represented by the chemical formula (1) at the initial stage of the polycondensation. Smaller is more preferable.

Diglycolic acid exists in various forms other than diglycolic acid alone, for example, forms a condensate with a compound containing another hydroxyl group, such as glycolic acid or a hydroxycarboxylic acid other than glycolic acid. In some cases, these are collectively referred to as diglycol units in order to include these.
The composition of the raw materials is appropriately determined so as to obtain a glycolic acid copolymer composition within the scope of the present invention after polycondensation. A preferable composition range is a reduced molar ratio of glycolic acid units of glycolic acid and / or a derivative thereof. , The reduced molar ratio of hydroxycarboxylic acid units other than glycolic acid in hydroxycarboxylic acids other than glycolic acid and / or derivatives thereof, and, if necessary, glycolic acid and / or derivatives thereof and hydroxycarboxylic acids other than glycolic acid and / or the same. A range in which the reduced molar ratio of the polyol unit and the reduced molar ratio of the polycarboxylic acid unit used as the copolymerization compound together with the derivative satisfy the following mathematical expressions (1), (2) and (3) can be exemplified.

（ただし、式中の［Ｘ−１］はグリコール酸及び／又はその誘導体の換算モル比、［Ｘ−２］はグリコール酸以外のヒドロキシカルボン酸及び／又はその誘導体の換算モル比、［Ｘ−３］、［Ｘ−４］は必要に応じて用いるポリオール、ポリカルボン酸及び／又はその誘導体の換算モル比を表し、［Ｘ−３］と［Ｘ−４］は独立して０であってもよい。）

(Where [X-1] is a reduced molar ratio of glycolic acid and / or its derivative, [X-2] is a reduced molar ratio of hydroxycarboxylic acid other than glycolic acid and / or its derivative, [X- 3] and [X-4] represent the reduced molar ratio of the polyol, polycarboxylic acid and / or derivative thereof used as needed, and [X-3] and [X-4] are independently 0. May be.)

Since a copolymer having a high molecular weight and having hydrolysis resistance or a copolymer having flexibility can be produced at a high polymerization rate, the reduced molar ratio of glycolic acid units of glycolic acid and / or a derivative thereof, other than glycolic acid The converted molar ratio of the hydroxycarboxylic acid unit other than glycolic acid of the hydroxycarboxylic acid and / or derivative thereof satisfies the above formulas (1) and (2), and the converted mole ratio of the polycarboxylic acid unit is the formula (4). Is satisfied, it is preferable that the reduced molar ratio of the polyol unit be in a range that satisfies the formula (5), more preferably a range that satisfies the formula (11). Most preferably, it is satisfied.

（ただし、［Ｘ−１］、［Ｘ−２］、［Ｘ−３］及び［Ｘ−４］は、上記と同じ。［Ｘ−４］は０であってもよい。）

(However, [X-1], [X-2], [X-3] and [X-4] are the same as above. [X-4] may be 0.)

On the other hand, the converted molar ratio of glycolic acid units of glycolic acid and / or a derivative thereof, and the converted molar ratio of hydroxycarboxylic acid units other than glycolic acid and / or hydroxycarboxylic acid units other than glycolic acid other than glycolic acid are represented by the formulas (1) and (2). When (2) is satisfied and the converted molar ratio of the polycarboxylic acid unit satisfies Expression (6), it is preferable that the converted molar ratio of the polyol unit be in a range satisfying Expression (7), It is more preferable that the expression (13) is satisfied, and it is most preferable that the expression (14) is satisfied.

（ただし、［Ｘ−１］、［Ｘ−２］、［Ｘ−３］及び［Ｘ−４］は、上記と同じ。）

(However, [X-1], [X-2], [X-3] and [X-4] are the same as above.)

In order to produce a glycolic acid copolymer having high gas barrier properties, the conversion molar ratio of glycolic acid units of glycolic acid and / or its derivative, hydroxycarboxylic acid other than glycolic acid and / or its derivative other than glycolic acid It is preferable that the reduced molar ratio of the hydroxycarboxylic acid unit, the reduced molar ratio of the polyol unit, and the reduced molar ratio of the polycarboxylic acid unit satisfy the formula (8).

（ただし、［Ｘ−１］、［Ｘ−２］、［Ｘ−３］及び［Ｘ−４］は、上記と同じ。［Ｘ−４］は０であってもよい。）

(However, [X-1], [X-2], [X-3] and [X-4] are the same as above. [X-4] may be 0.)

In the present invention, a hydroxyl group and / or a carboxyl group in one unit structure of a polyhydroxy monocarboxylic acid unit, a monohydroxy polycarboxylic acid unit, a polyhydroxy polycarboxylic acid unit, a polyol unit, a polycarboxylic acid unit or the like as a raw material. When the total amount of the groups includes a compound unit of 3 or more, the total of the reduced molar ratios of the unit is preferably 0.0007 or less, more preferably 0.0005 or less, and most preferably 0.0003 or less. If it exceeds the above range, processability such as stretchability may be reduced in the obtained copolymer.
The polycondensation can be carried out without adding a catalyst, but a catalyst can be used if necessary to increase the polycondensation rate.

Examples of the catalyst include metals, metals salts, metal oxides, metal hydroxides, metal alkoxides, metal sulfonates, and the like of metals of Groups IA, IIA, IIIA, IV, VA, VIII, IVB, and VB of the periodic table of the elements. . For example, metals such as titanium, zirconium, niobium, tungsten, zinc, germanium, tin, and antimony; metal oxides such as magnesium oxide, titanium oxide, zinc oxide, germanium oxide, silica, alumina, tin oxide, and antimony oxide; and fluorides Tin, antimony fluoride, magnesium chloride, aluminum chloride, zinc chloride, stannous chloride, stannic chloride, stannous bromide, stannic bromide, aluminum sulfate, zinc sulfate, tin sulfate, magnesium carbonate, carbonic acid Metal salts such as calcium and zinc carbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, aluminum hydroxide, zirconium hydroxide, iron hydroxide, water Metal hydroxides such as cobalt oxide, nickel hydroxide, copper hydroxide, zinc hydroxide, etc. Metal carboxylate such as magnesium oxide, aluminum acetate, zinc acetate, tin acetate, tin octoate, tin stearate, iron lactate, tin lactate, and metals such as magnesium, lanthanoid, titanium, hafnium, iron, germanium, tin, antimony Organic metals such as alkoxide and dibutyltin oxide; organic sulfonates such as tin methanesulfonate, tin trifluoromethanesulfonate and tin p-toluenesulfonate; and ion exchange resins such as Amberlite and Dowex.

Further, inorganic acid catalysts such as hydrochloric acid, perchloric acid, nitric acid, nitrous acid, sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, and polyphosphoric acid; and organic acids such as p-toluenesulfonic acid, naphthalenesulfonic acid, and methanesulfonic acid. Is mentioned. The catalyst is not limited to these, and one kind or a combination of two or more kinds can be used.
These catalyst species are added, for example, to a monomer solution containing a raw material monomer or an aqueous solution, or used after obtaining a polycondensate. In addition, if necessary, water and / or After hydrolysis in the presence of hydroxycarboxylic acid, it may be used by adding it to the raw material monomer or polycondensate.

The polycondensate here is not limited in molecular weight and the like as long as further melt polymerization is possible.
The amount of the catalyst used is preferably in the range of 1 × 10 ⁻¹⁰ mol to 1 × 10 ⁻² mol as metal atoms per 1 g of the monomer used as the raw material. When the amount of the catalyst used per 1 g of the monomer used as the raw material is less than 1 × 10 ⁻¹⁰ mol as a metal atom, the effect of increasing the polycondensation rate is not sufficiently exhibited, and the amount exceeds 1 × 10 ⁻² mol. In such cases, side reactions such as coloring of the resin tend to increase significantly.
In order to suppress coloring due to thermal deterioration during polycondensation, a polycondensation reaction may be performed by adding a coloring inhibitor. The coloring inhibitor can be added to the reaction system as it is, or after being dissolved or mixed in an appropriate liquid. There is no limitation on the timing of addition of the coloring inhibitor, and it may be added to the reaction system at any time as long as it is from the step of concentrating or condensing the raw material monomers until the polycondensation reaction is substantially completed. The addition may be made at once or may be divided.

Examples of the coloring preventing agent used for the polycondensation include phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, monoethyl polyphosphate, diethyl polyphosphate, pyrophosphoric acid, triethyl pyrophosphate, and hexamethyl pyrophosphate. Amide, phosphorous acid, triethyl phosphite, triphenyl phosphite, tris (2-tert-butylphenyl) phosphite, tris (2,4-ditert-butylphenyl) phosphite, tris (2,5- Di-tert-butylphenyl) phosphite, tris (2-tert-butyl-4-methylphenyl) phosphite, tris (2-tert-butyl-5-methylphenyl) phosphite, tris (2-tert-butyl-4) , 6-dimethylphenyl) phosphite, trisnonylphenylphosphite, tris (mono and dino) Butylphenyl) phosphite phosphoric acid compounds such as are preferably used.

These heat stabilizers can be used alone or in combination of two or more. The rate of addition of the thermal stabilizer is preferably in the range of 0.0005% by mass to 10% by mass, and more preferably in the range of 0.005% by mass to 6% by mass, based on the raw material monomer. The effect of preventing coloring does not increase even if the addition ratio of the heat stabilizer exceeds 10% by mass, and the effect of preventing coloring does not sufficiently appear when the addition ratio is less than 0.0005% by mass. There is no restriction on the timing of adding these heat stabilizers, and it is possible to add them directly to the raw materials, during the course of the polycondensation reaction, or even after the polymerization reaction is completed.
Next, [Steps (A), (B) and (C)] in producing the glycolic acid copolymer of the present invention will be described.

[Step (A)]
[Step (A)] includes glycolic acid and / or a derivative thereof, and a compound copolymerizable with the glycolic acid and / or a derivative thereof, including a hydroxycarboxylic acid other than glycolic acid and / or a derivative thereof. Using the raw materials, the polycondensation reaction is performed at a temperature in the range of 20 ° C to 160 ° C, preferably 50 ° C to 160 ° C, more preferably 80 ° C to 160 ° C, and the weight average molecular weight is 700 to 5,000, preferably Produces a glycolic acid copolymer of 1,000 to 4,000, more preferably 1,200 to 3,000.

When the polycondensation reaction temperature is lower than 20 ° C., the reaction rate becomes extremely slow. When the reaction temperature exceeds 160 ° C., the polycondensation reaction rate is increased, but the amount of diglycolic acid units formed by a side reaction in the obtained glycolic acid copolymer increases, and the reaction is subsequently carried out. In the polycondensation step, not only is it difficult to increase the molecular weight, but also the thermal stability of the resulting glycolic acid copolymer decreases.
When the weight average molecular weight of the glycolic acid copolymer obtained in [Step (A)] is less than 700, the amount of diglycolic acid units formed is suppressed under the subsequent polycondensation conditions at a high reaction temperature. Is not enough. If the weight average molecular weight of the glycolic acid copolymer obtained in this step exceeds 5,000, the glycolic acid copolymer may vary depending on the composition of the glycolic acid copolymer, the type and the molecular weight of the copolymerized compound. Precipitation tends to occur, making it difficult to continue polycondensation in the molten state.

If the reaction temperature of [Step (A)] is in the range of 20 ° C. or more and 160 ° C. or less, the temperature does not need to be constant during the reaction, and the temperature may be gradually increased, gradually decreased, or a combination thereof. .
The reaction of [Step (A)] includes one or two or more inert gases selected from nitrogen, helium, neon, argon, krypton, xenon, carbon dioxide, lower saturated hydrocarbons having 1 to 4 carbon atoms, and the like. It is preferable to carry out the reaction under an atmosphere and / or under reduced pressure. When the reaction is carried out under reduced pressure, the pressure is usually in the range of 1.3 Pa to 1.014 × 10 ⁵ Pa, although it depends on the composition of the glycolic acid copolymer, the type of the copolymer compound, and the reaction temperature. It is. At this time, under normal pressure, a method of flowing an inert gas under normal pressure, a method of flowing an inert gas under reduced pressure, a method and a combination thereof, and further, a reaction temperature and / or an operating pressure are adjusted in multiple stages. The method of performing polycondensation while performing is preferable. The reaction can be carried out using a single reactor or a combination of multiple reactors.

However, the end point of [Step (A)] (that is, the starting point of [Step (B)]) is determined to be a temperature increase when a glycolic acid copolymer having a weight average molecular weight of 700 or more and 5,000 or less is obtained. The time to start warming. After the glycolic acid copolymer having a weight average molecular weight of 700 or more is obtained, when the temperature is raised a plurality of times, or when the temperature is raised or lowered one or more times, this is the starting point of the last temperature rise.

[Step (B)]
In [Step (B)], the glycolic acid copolymer having a weight average molecular weight of 700 or more and 5,000 or less obtained in [Step (A)] is successively added from the reaction temperature of [Step (A)], The temperature is raised to 190 ° C. within 100 minutes, preferably within 80 minutes, more preferably within 60 minutes. The heating time is not limited, but is preferably 0.1 second or more, more preferably 1 minute or more.

When the reaction temperature after the temperature rise is less than 190 ° C., or when the temperature rise time to 190 ° C. exceeds 100 minutes, the reaction rate of forming the diglycolic acid unit with respect to the rate of the polycondensation reaction is not sufficiently small. A high-molecular-weight glycolic acid copolymer having excellent melt heat stability cannot be obtained by the subsequent polycondensation reaction in [Step (C)].
In the [Step (B)], the weight average of the glycolic acid copolymer after the completion of the [Step (A)], that is, when the reaction temperature is increased to 190 ° C. after the start of the [Step (B)]. The rate of increase in molecular weight is preferably 300 or more in terms of an average value per hour. The rate of increase in the weight average molecular weight is preferably as high as possible to suppress the formation of diglycolic acid units.

方式 The method of raising the temperature in this step is not limited. For example, when the reaction of at least a part of [Step (A)] and the reaction of [Step (C)] performed after [Step (B)] are performed in the same reactor, the reactor A method in which the temperature is raised while performing a polycondensation reaction under reduced pressure inside the reactor, the reaction solution is once withdrawn from the reactor, passed through a heat exchanger, etc., and then returned to the reactor using a device equipped with a mechanism for returning to the reactor again A method of raising the temperature in the main body and / or the heat exchanger can be used. When [Step (A)] and [Step (C)] are performed in different reactors, a method such as performing [Step (B)] in a transfer pipe can be used. The above methods may be performed in an appropriate combination.

[Step (C)]
[Step (C)] is a step of heating the glycolic acid copolymer that has passed through [Step (B)] to a temperature of 190 ° C. or more and 300 ° C. or less to increase the molecular weight of the glycolic acid copolymer. After the reaction temperature reaches 190 ° C. or higher, the amount of increase in the weight average molecular weight until the weight average molecular weight of the glycolic acid copolymer becomes 10,000 or more is 1,000 or more per hour, preferably It is 2,000 or more, more preferably 3,000 or more. The reaction temperature is preferably 250 ° C. or lower, more preferably 230 ° C. or lower.
After the reaction temperature reaches 190 ° C., an increase in weight-average molecular weight per hour until the weight-average molecular weight of the glycolic acid copolymer reaches 10,000 (hereinafter sometimes abbreviated as M). Is based on the time when the reaction temperature reaches 190 ° C., the weight average molecular weight at the time when the reaction temperature reaches 190 ° C. is Mw1, and the time required for the weight average molecular weight to reach 10,000 is T1 (time ) Means a value represented by Expression (10).

When the reaction temperature in the case of producing a glycolic acid copolymer having a weight average molecular weight of 10,000 or more is less than 190 ° C, or after the reaction temperature becomes 190 ° C or more, until the weight average molecular weight becomes 10,000. If the weight-average molecular weight increase of the compound is less than 1,000 per hour, the rate of formation of the diglycolic acid unit with respect to the rate of the polycondensation reaction is not sufficiently small. A glycolic acid copolymer having a molecular weight cannot be obtained. On the other hand, when the polycondensation is carried out at a reaction temperature exceeding 300 ° C., the coloration of the glycolic acid copolymer due to thermal decomposition is significantly increased.
In [Step (C)], if the increase in the weight-average molecular weight until the weight-average molecular weight becomes 10,000 or more per hour is 1,000 or more and the reaction temperature is in the range of 190 to 300 ° C, The temperature does not need to be constant, and the temperature may be gradually increased, gradually decreased, or a combination thereof.

The method for performing the polycondensation within the scope of the present invention is not limited, and for example, the reaction temperature, the reaction pressure, the glycolic acid copolymer in a molten state during the reaction may be used as a factor controlling the reaction rate. A method of controlling the surface area where the coalescing is in contact with the gas phase, the stirring state of the glycolic acid copolymer in the molten state during the reaction, and the like can be mentioned.
The reaction is carried out under the flow of one or more inert gases selected from nitrogen, helium, neon, argon, krypton, xenon, carbon dioxide, lower saturated hydrocarbons having 1 to 4 carbon atoms, and / or under reduced pressure conditions. Can be implemented below. In order to increase the polycondensation reaction rate, it is preferable to carry out the reaction under reduced pressure. When the reaction is carried out under reduced pressure, the composition varies depending on the composition of the glycolic acid copolymer, the type of the copolymerized compound, the reaction temperature, the presence or absence of the catalyst, and the type of the catalyst. ^The reaction is carried out at a pressure of ³ Pa or less, preferably 1.3 × 10 Pa or more and 9.3 × 10 ² Pa or less, more preferably 6.5 × 10 Pa or more and 6.7 × 10 ² Pa or less. At this time, under reduced pressure, a method of flowing an inert gas under reduced pressure, operating conditions such as reaction temperature and reaction pressure in this step, the temperature and the increase in weight average molecular weight per hour are within the scope of the present invention. You may change within the range which satisfies.

The surface area of the glycolic acid copolymer in the molten state during the reaction in contact with the gas phase is not limited. The larger the surface area of the copolymer in contact with the gas phase, the easier it is to distill the condensed water out of the reaction system, which is preferable because the polycondensation reaction can proceed promptly.
On the other hand, the stirring state of the glycolic acid copolymer in the molten state during the reaction, the more the stirring state is improved, the easier it is to distill the condensed water out of the reaction system, and the polycondensation reaction proceeds rapidly. It is preferable because it becomes possible.
In [Step (C)], the time required for the polycondensation reaction is at least as long as the weight-average molecular weight of the glycolic acid copolymer increases by 1,000 or more per hour. The time is not limited as long as the average molecular weight becomes 10,000. For example, the reaction time is preferably from 10 minutes to 9 hours, more preferably from 30 minutes to 4.5 hours, and most preferably from 45 minutes to 3.5 hours.

グ リ コ ー ル In [Step (C)], the glycolic acid copolymer of the present invention having a weight average molecular weight of 50,000 or more can be obtained by appropriately selecting the reaction temperature, reaction time, reaction apparatus and the like. After obtaining a glycolic acid copolymer having a molecular weight of less than 50,000 in [Step (C)], polycondensation is performed under conditions that do not satisfy the requirements of [Step (C)], for example, by lowering the reaction temperature. To obtain a glycolic acid copolymer of the present invention having a weight average molecular weight of 50,000 or more. Of course, after obtaining the glycolic acid copolymer having a weight-average molecular weight of 50,000 or more in [Step (C)], the conditions not satisfying the requirements of [Step (C)], such as lowering the reaction temperature, are used. The polycondensation reaction may be continued to further increase the molecular weight.

After the end of [Step (C)], the obtained glycolic acid copolymer can be subsequently subjected to a polycondensation reaction at a reaction temperature in the range of 190 ° C to 300 ° C.
The reaction time when the polycondensation reaction is continued is optional, and the composition of the desired glycolic acid copolymer, the type of the copolymerized compound, the molecular weight of the target glycolic acid copolymer, the type of the polycondensation apparatus used, It depends on the reaction conditions. The reaction time is preferably 1 minute to 200 hours, more preferably 10 minutes to 150 hours, still more preferably 1 hour to 120 hours, and most preferably 1.5 hours to 100 hours.
The reaction can be carried out under a flow of inert gas such as nitrogen, helium, neon, argon, krypton, xenon, carbon dioxide, lower saturated hydrocarbon and / or under reduced pressure. In order to increase the polycondensation reaction rate, it is preferable to carry out the reaction under reduced pressure. When the reaction is carried out under reduced pressure, the composition varies depending on the composition of the glycolic acid copolymer, the type of the copolymerized compound, the reaction temperature, the presence or absence of the catalyst, and the type of the catalyst. ^The reaction is carried out at a pressure of ³ Pa or less, preferably 1.3 × 10 Pa or more and 9.3 × 10 ² Pa or less, more preferably 6.5 × 10 Pa or more and 6.7 × 10 ² Pa or less.

In the polycondensation reaction following [Step (C)], glycolic acid having a weight average molecular weight of more than 10,000 and 1,000,000 or less can be obtained by appropriately selecting the type and amount of the catalyst, the reactor, the reaction conditions, and the like. A copolymer can be produced.
Further, in the present invention, after the [Step (C)] is completed, a known compound having an isocyanate group or an epoxy group having two or more functionalities is replaced with a glycolic acid copolymer in a molten state as long as the effects of the present invention are not impaired. It is also possible to add to the coalescence. When these compounds are added to the glycolic acid copolymer, the content is usually 0.05 to 5% by mass.
These reactions of [Steps (A), (B), (C)] and the polycondensation reaction carried out subsequent to [Step (C)] may be carried out in the same reactor, or may be carried out in different reactors. It may be performed in a reactor. In addition, the reaction can be carried out in a batch and / or continuous reaction mode.

There is no limitation on the reactor used for the polycondensation reaction of the present invention and further for the polycondensation reaction subsequently performed after [Step (C)] of the present invention. For example, no baffle plate or no baffle plate is provided. Stirred tank reactor, surface-renewed stirred tank reactor, thin-film reactor, centrifugal thin-film evaporation reactor, surface-renewed twin-screw kneading reactor, wet-wall reactor, perforated plate for polycondensation while falling freely A polycondensation reactor, for example, a wire type perforated plate type reactor or the like, in which a molten polymer is dropped along a support to promote polycondensation along a support, can be used. These reactors can be used alone or in combination of two or more. Further, these can be used in combination with a known heat exchanger as a means for achieving the heating rate in the present invention.

When a stirred tank reactor is used as the reactor, it is possible to use a reaction tank provided with a baffle plate and use a known stirring blade as needed.
There is no limitation on the shape of the baffle, the installation method, and the like. For example, the shape and the installation method of the baffle described in the September issue of Chemical Equipment, p13 (1981) can be used.
Specific examples of the stirring blade include propeller blades, angled flat blades, flat blades described in Chemical Engineering Handbook, Fifth Edition, Fifth Edition, pages 887 to 919 (issued on November 15, 1995, issued by Maruzen Co., Ltd.). Others such as pitched flat blades, flat blade disk turbine blades, curved blades, faudler type blades, bull margin type blades, max blend blades, helical screw blades, helical ribbon blades, anchor blades, screw anchor blades, paddle blades, spiral blades, etc. , Chemical Equipment, September issue, p.11-17 (1981), a double ribbon wing, and a product name, Logbone, manufactured by Shinko Pantech Co., Ltd.

Specific examples of the surface renewal type stirred tank reactor include an advanced ribbon reactor (AR) (trademark) manufactured by Mitsubishi Heavy Industries, Ltd., a vertical cone reactor (VCR) (trademark) manufactured by Mitsubishi Heavy Industries, and a log bone manufactured by Shinko Pantech Co., Ltd. (LOGBORN) (trademark), Torsion lattice blade polymerization machine (trademark) manufactured by Hitachi, Ltd., Super Blend (concentric twin shaft type stirring tank) manufactured by Sumitomo Heavy Industries, Ltd. (trademark), manufactured by Nissen Corporation Bicester (high viscosity stirrer) (trademark) and the like.
Specific examples of the surface renewal type twin-screw kneading reactor include a horizontal twin-screw high-viscosity reactor (HVR) (trademark) manufactured by Mitsubishi Heavy Industries, Ltd., a self-cleaning reactor (SCR) (trademark) manufactured by the company, New self-cleaning type reactor (N-SCR) (trademark), Hitachi Glasses blade high-viscosity liquid processing machine (trademark) manufactured by Hitachi, Ltd., lattice blade polymerization machine (trademark) manufactured by Hitachi, Ltd., manufactured by Sumitomo Heavy Industries, Ltd. BIVOLAK (horizontal twin-screw reactor) (trademark), KRC Kneader (trademark) manufactured by Kurimoto Iron Works, Ltd., and the like.

Among these combinations, in the polycondensation reaction of the present invention, a method of performing polycondensation by combining a vertical stirring tank and / or a surface-renewal stirring tank reactor is preferable. When the melt polycondensation reaction is subsequently performed after [Step (C)] of the present invention, a tank-type stirring tank, a surface-renewal-type stirring vessel reactor, a surface-renewal-type twin-screw kneading reactor, a wet-wall type It is preferable to use a single reactor or a combination of two or more reactors, a perforated plate reactor in which polycondensation is performed while free falling, and a polycondenser in which molten polymer is dropped along a support to advance polycondensation.
When the melt polycondensation reaction is subsequently performed after the [Step (C)] of the present invention, the polycondensation under a reduced pressure after absorbing the inert gas into the glycolic acid copolymer in a molten state is performed by: This is a more preferable method. In this case, compared to the case where polycondensation is performed without absorbing an inert gas, a vigorous foaming phenomenon occurs in the glycolic acid copolymer in a molten state, and this phenomenon causes the inside and surface of the glycolic acid copolymer in a molten state. Since the stirring state in the above is improved, a glycolic acid copolymer can be obtained at a high polycondensation rate.

Specific examples of the inert gas to be absorbed by the glycolic acid copolymer in a molten state include nitrogen, helium, neon, argon, krypton, xenon, carbon dioxide, and lower hydrocarbons having 1 to 4 carbon atoms. Preferably it is nitrogen. These gases can be used as one kind or a mixture of two or more kinds.
The glycolic acid copolymer obtained by performing the melt polycondensation reaction subsequent to [Steps (A) to (C)] or [Step (C)] can be granulated.
There is no limitation on the method of granulating the glycolic acid copolymer. Lump or strand by solidifying in an inert gas in one or two or more gases selected from inert gases such as lower saturated hydrocarbons and gases such as air, and crushing or cutting Into particles, pellets, etc., by contacting with a liquid such as water, into particles, pellets, etc., into a lump by contact with a liquid such as water, and crush this lump And a method in which the glycolic acid copolymer in a molten state is transferred to an extruder and pelletized. The method of bringing the glycolic acid copolymer in a molten state into contact with a liquid such as water is not limited at all. Pellets are obtained.

The particle shape and pellet shape of the granulated glycolic acid copolymer are not limited, but general shapes are powder, pulverized, chip, spherical, cylindrical, tablet, marble, and the like. .
The particle size of the glycolic acid copolymer is not limited. In general, the smaller the particle size of the solid polymer, the larger the surface area is, so that the surface area increases, which is advantageous in terms of the polymerization reaction. However, since the handleability is reduced, it is usually 10 μm to 20 mm, preferably 0.1 mm. Not less than 10 mm.
When the granulation is performed by contacting with a liquid such as water, drying may be subsequently performed by a known method.

In the present invention, when the glycolic acid copolymer obtained by performing a melt polycondensation reaction subsequent to [Steps (A) to (C)] or [Step (C)] is crystalline, Crystallization after glycolic acid copolymer granulation, granulation after crystallization, granulation, solid phase polymerization after simultaneous crystallization and granulation to produce the glycolic acid copolymer of the present invention Is the preferred mode.
In order to provide good crystallinity, the content of glycolic acid units is preferably 82 mol% or more, more preferably 83 mol% or more, and most preferably 85 mol% or more when performing solid-phase polymerization. .

方法 The method of crystallizing the granulated glycolic acid copolymer is not limited, and a known method can be used. For example, it is composed of one or more selected from an inert gas such as nitrogen, helium, neon, argon, krypton, xenon, carbon dioxide, a lower saturated hydrocarbon having 1 to 4 carbon atoms, and a gas such as air. A method of crystallizing by heating while performing mechanical stirring and / or flowing under a gas atmosphere, under circulation, under reduced pressure or under pressure, or a combination thereof, nitrogen, helium, neon, argon, krypton, xenon In an atmosphere of an inert gas such as carbon dioxide, a lower saturated hydrocarbon having 1 to 4 carbon atoms or the like, under flow, under pressure or under reduced pressure, or a combination thereof, by heating while stirring and flowing with a gas. Liquid to dissolve the solid glycolic acid copolymer at the crystallization temperature, for example, water, alcohol , Aliphatic hydrocarbons, aromatic hydrocarbons, ketones, ethers, and a method of contacting with esters are used.

Further, as a mode, a method of performing in a stationary state, a method of performing while adding mechanical stirring (for example, a method of using a stirring blade), by rotating or vibrating a vertical, horizontal, or oblique tank or tower itself Examples of the method include a method in which solid mixing is performed, a method in which the phase is shifted from the upper part of the vertical or oblique type tank or tower to the lower part, or a lower part to the upper part, and a method in which the liquid is flowed by gas.
The temperature at which the crystallization treatment is performed varies depending on the type of the copolymerized compound of the glycolic acid copolymer, the composition ratio, and the like, but is in the range from the glass transition temperature of the glycolic acid copolymer to 220 ° C. This crystallization treatment can be performed in multiple stages. The time required for the crystallization treatment of the glycolic acid copolymer is arbitrary. Generally, it is 0.5 minutes or more and 10 hours or less, preferably 1 minute or more and 8 hours or less, more preferably 5 minutes or more and 6 hours or less. The crystallization treatment can be performed in a batch and / or continuous reaction mode. Further, it can be carried out in multiple stages.

The glycolic acid copolymer after the crystallization treatment is hereinafter referred to as a crystallized glycolic acid copolymer in the present specification.
The weight-average molecular weight of the crystallized glycolic acid copolymer when subjected to solid-state polymerization is from 10,000 to 500,000 in order to exhibit the characteristics of the present invention, and a high molecular weight having sufficient mechanical strength In order to stably produce the glycolic acid copolymer at a high polymerization rate, the weight average molecular weight of the crystallized glycolic acid copolymer is preferably from 25,000 to 300,000, and from 30,000 to 200,000. 4,000 or less, more preferably 40,000 or more and 150,000 or less. When the weight average molecular weight exceeds 500,000, the polycondensation time in the molten state for producing the glycolic acid copolymer increases, which may lead to coloring of the glycolic acid copolymer.

The solid phase polymerization reaction can be performed under an inert gas flow, under reduced pressure, under increased pressure, or a combination thereof. At this time, since it is necessary to remove water generated by the polymerization, it is preferable to carry out the reaction under an inert gas flow and / or under reduced pressure. When the solid-phase polymerization is performed under an inert gas flow, the inert gas is selected from nitrogen, helium, neon, argon, krypton, xenon, carbon dioxide, lower saturated hydrocarbon having 1 to 4 carbon atoms, and the like. Species or a gas composed of two or more species. The inert gas to be circulated is preferably a dry gas having a water content as low as possible and substantially anhydrous. In this case, the gas can be passed through a layer filled with a molecular sieve or the like or an ion exchange resin or the like, or the gas can be cooled to a low temperature for dehydration before use. When the water content of the flowing gas is indicated by the dew point, it is preferably -10 ° C or lower, more preferably -40 ° C or lower.

The flow rate of the flowing gas is such that the shape, particle size, crystallinity, reaction temperature, degree of reduced pressure, etc. of the crystallized glycolic acid copolymer are taken into consideration, and a glycolic acid copolymer having a sufficiently high weight average molecular weight can be obtained. It suffices if the water generated in step (1) can be distilled off. In general, the higher the flow rate of the flowing gas, the higher the efficiency of removing the generated water. However, usually, per gram of the crystallized prepolymer, 0.0005 ml / min or more and 3000 ml / min or less in terms of normal pressure, preferably 0.001 ml / min to 2500 ml / min, more preferably 0.0015 ml / min to 2000 ml / min, and most preferably 0.002 ml / min to 500 ml / min.
When the solid-state polymerization reaction is performed under reduced pressure, the degree of reduced pressure in the reaction system substantially maintains the progress of the solid-state polymerization reaction, as long as a glycolic acid copolymer having a sufficiently high weight average molecular weight can be obtained. Good. From the viewpoint of the polymerization rate and the attained weight average molecular weight, the preferable degree of reduced pressure is in the range of 13.3 Pa to 1.33 × 10 ³ Pa. When the solid-state polymerization reaction is performed under pressure, the pressure in the reaction system is within a range where a glycolic acid copolymer having a sufficiently high weight average molecular weight can be obtained while substantially maintaining the progress of the solid-state polymerization reaction. Is good enough. For example, the pressure at which the reaction is performed under pressure is preferably in the range of more than normal pressure and 1 MPa or less, more preferably in the range of more than normal pressure and 0.5 MPa or less.

The reaction temperature at the time of performing the solid-phase polymerization is not limited as long as the crystallized glycolic acid copolymer present in the reaction system substantially maintains a solid state. And it is preferable that it is below melting | fusing point of a crystallized glycolic acid copolymer, More preferably, it is 120 degreeC or more, and (melting point -5 degreeC) or less of a crystallized glycolic acid copolymer, More preferably, it is 140 degreeC or more, And it is the temperature range of (melting point -10) degreeC or less of a crystallized glycolic acid copolymer. At this time, the reaction temperature at the time of performing the solid-phase polymerization does not need to be constant during the reaction as long as it is within the above-mentioned temperature range.
During the solid-state polymerization reaction, if the melting point of the crystallized glycolic acid copolymer rises due to an increase in molecular weight or the effect of annealing, raise the reaction temperature to the melting point range of the crystallized glycolic acid copolymer at that time, and then perform solid-state polymerization. It is also possible to carry out the reaction.

The solid-state polymerization reaction can be performed by combining one or two or more batch-type and / or continuous-type reaction devices.
There is no limitation on the reactor for performing the solid-phase polymerization, and a known dryer, for example, described in Chemical Engineering Handbook, 5th edition, 5th printing, pp. 673-691 (published on November 15, 1995, published by Maruzen Co., Ltd.) Parallel flow band, tunnel dryer, ventilation band dryer, jet flow dryer, ventilation vertical (moving bed) dryer, cylindrical and groove type stirring dryer, net dryer, disk dryer, rotary dryer, ventilation A rotary drier, a fluidized bed drier, a conical rotary drier, a spray drier, a flash drier, a multi-cylinder drier, or a hopper-type drier may be used.

The weight average molecular weight of the glycolic acid copolymer obtained by the solid phase polymerization according to the present invention is usually 1,000,000 or less.
A series of polycondensation steps comprising [Steps (A), (B) and (C)] of the present invention, followed by melt polycondensation and solid phase polymerization which can be carried out subsequently, are carried out continuously. Or may be performed in a divided manner.
The glycolic acid copolymer obtained in the present invention can be modified with an acid anhydride such as acetic anhydride, an epoxy compound or the like after the polycondensation reaction, if necessary, to modify the terminal.
There is no limitation on the material of the polycondensation device used in the present invention. It is selected in consideration of. The surface of the polycondenser may be subjected to various treatments such as plating, lining, passivation treatment, acid washing, and alkali washing as needed.

The glycolic acid copolymer of the present invention may contain, if necessary, known heat stabilizers, phenol-based, thioether-based antioxidants, etc., ultraviolet inhibitors, hindered amine-based light stabilizers, moisture-proofing agents, waterproofing agents. , Water repellents, lubricants, release agents, pigments, dyes, nucleating agents, plasticizers, inorganic fillers, fatty acid metal salts such as calcium stearate, other thermoplastic resins, etc., alone or in combination of two or more Can be added or blended. The amount of these additives is usually in the range of 0.0005% by mass to 40% by mass, preferably in the range of 0.001% by mass to 30% by mass.
The glycolic acid copolymer obtained according to the present invention has a high gas barrier property, has practical mechanical strength, and has a heat stability of a resin which is a disadvantage of the glycolic acid copolymer, or a heat aging resistance. Because of the improvement, a molded article having excellent transparency and whiteness can be obtained even after being melted and processed into a molded article, or if necessary, subjected to heat treatment after molding.

As a processing method, a known method, for example, extrusion molding, compression molding (press molding), injection molding, hollow molding, solution casting method, or the like can be applied. Can be.
By the above method, it is possible to produce various molded articles such as pellets, films or sheets, multilayer films or sheets, injection molded articles, foams, hollow containers, multilayer hollow containers, fibers and the like. Among these, in addition to pellets that can be processed into various molded articles, films or sheets, multilayer films or sheets, hollow containers or multilayer hollow containers can make full use of features such as gas barrier properties, biodegradability, and transparency. Therefore, it is preferable. In addition, a foam is also preferable because it can exhibit a heat-resistant aging characteristic in addition to the above-described characteristics. Further, as a specific example, it can be used as a compounding agent such as a slow-acting fertilizer and a capsule for a fertilizer for agriculture or horticulture as a special example.

When processing into the above molded product, in the post-processing step or finishing step, welding, heat sealing, perforation, primer application, adhesive application, chemical application, parkerizing, vapor deposition, sputtering, CVD, coating, etching, spraying Printing, dyeing, painting, electrostatic painting, air brushing, laminating, sandwiching, embossing, three-dimensional patterning, embossing, corrugating, printing, transfer, sanding, sandplast, shearing, punching, punching, honeycomb structuring, corrugated cardboard Post-processing such as formation of a laminated body or finishing by structuring, laminating or bonding with paper or other thermoplastic resin, or the like can also be performed. Depending on the purpose, the post-treatment step or the finishing step may include a calendar method, an extrusion method, a screen printing method, a gravure printing method, a letterpress method, an intaglio method, a doctor blade method, an immersion method, a spray method, an air brush method, and an electrostatic coating method. And other known methods.

When processing into the above applications, the glycolic acid copolymer of the present invention alone, or the glycolic acid copolymer and other thermoplastic resins, inorganic fillers, plasticizers, etc., each alone, or 2 It can be used as a composition which is mixed or blended in combination of more than one species. The amount of other thermoplastic resins, inorganic fillers, plasticizers and the like is appropriately selected depending on gas barrier properties, biodegradability, moldability, etc., but the content of the glycolic acid copolymer of the present invention in the composition Is usually 50% by mass or more.
Other thermoplastic resins mixed or blended with the glycolic acid copolymer of the present invention include, for example, polylactic acid, polycaprolactone and copolymers thereof, and polymers of ethylene glycol with succinic acid and / or adipic acid , A copolymer of butanediol with succinic acid and / or adipic acid, a polymer or copolymer of ethylene oxalate, poly2-hydroxybutanoic acid, poly3-hydroxybutanoic acid, poly4-hydroxybutanoic acid, hydroxy Butanoic acid-hydroxyvaleric acid copolymer, cellulose acetate, polyvinyl alcohol, starch, polyglutamic acid ester, natural rubber, polyethylene, polypropylene, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, polymethyl methacrylate, polystyrene, styrene -Butadiene-styrene Down block copolymer, hydrogenated styrene - butadiene - styrene block copolymers, ABS resins, ethylene - include thermoplastic resins such as vinyl alcohol copolymer. These thermoplastic resins can be used alone or in combination of two or more.

As the inorganic filler mixed or blended with the glycolic acid copolymer of the present invention, alumina, silica, silica alumina, zirconia, titanium oxide, iron oxide, boron oxide, calcium carbonate, calcium silicate, calcium phosphate, calcium sulfate, Magnesium carbonate, magnesium silicate, magnesium phosphate, magnesium sulfate, kaolin, talc, mica, ferrite, carbon, silicon, silicon nitride, molybdenum disulfide, glass, inorganic powders such as potassium titanate, whiskers, fibers and the like. Can be These inorganic fillers can be used alone or in combination of two or more.
Examples of the plasticizer mixed or blended with the glycolic acid copolymer of the present invention include phthalic acid esters such as di (methoxyethyl) phthalate, dioctyl phthalate, diethyl phthalate and benzyl butyl phthalate, diethylene glycol dibenzoate, ethylene glycol Benzoic acid esters such as benzoyl dibenzoate; aliphatic dibasic acid esters such as octyl adipate and octyl sebacate; aliphatic tribasic acid esters such as acetyl citrate tributyl and acetyl triethyl citrate; dioctyl phosphate; tricresyl phosphate And epoxy plasticizers such as epoxidized soybean oil and epoxidized linseed oil, and polyalkylene glycol esters such as polyethylene glycol sebacate and polypropylene glycol laurate. These plasticizers can be used alone or in combination of two or more.

In the case of multilayer films and sheets, or multilayer hollow containers, ultra low density polyethylene, linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, ethylene-propylene rubber, ethylene-vinyl acetate copolymer Copolymer, ethylene-acrylate copolymer, polyolefin such as ionomer, polyester such as polyethylene terephthalate, polyethylene naphthalate, polystyrene, impact-resistant polystyrene, styrene-butadiene-styrene block copolymer, hydrogenated styrene-butadiene-styrene Polystyrene resins such as block copolymers, polyvinyl chloride resins such as hard or soft polyvinyl chloride, polycarbonate, polyamide, polyurethane, ethylene-vinyl alcohol copolymer, Biodegradability of vinylidene chloride resin, polylactic acid, polycaprolactone, polymer of ethylene glycol and succinic acid and / or adipic acid, copolymer of butanediol and succinic acid and / or adipic acid, etc. It can have a layer formed from a thermoplastic resin or the like. The above-mentioned thermoplastic resin is used alone or as a mixture of the glycolic acid copolymer and another thermoplastic resin, an inorganic filler, a plasticizer, etc., alone or in combination of two or more, or a mixture thereof. Can be used as

Films containing a glycolic acid copolymer include, for example, medical equipment packaging, wrap film, article packaging, doll packaging, fresh packaging, vegetable packaging, egg pack, retort food packaging, instant food packaging , Food packaging materials such as food wrap films, envelope window films, cushion materials, air cushion materials, multi-films, shopping bags, carrier bags, garbage bags, fertilizer bags, sanitary products packaging materials, disposable diapers, adhesive tapes and magnetic tapes And the like, and a floppy (registered trademark) disk cover. Further, the unheated oriented film can be used as a heat-shrinkable film. The split yarn can be used as a string material for agriculture and the like.

The sheet containing the glycolic acid copolymer is usually subjected to secondary processing, for example, a microwave oven container such as a tray or a cup, a retort food packaging material, or a high-temperature sterilization, ethylene oxide gas sterilization, or gamma ray sterilization. It can be preferably used as a medical device packaging material, a hot water injection type instant food container (cup, etc.), a disposable tableware, a lunch box, an egg pack, a cushion material, a stationery, a doll case and the like.
Injection molded products containing glycolic acid copolymers are used for daily necessities such as tableware, boxes and cases, bottles, kitchenware, pots for flowering plants, stationery such as ballpoint pens, mechanical pens, pencils, and appliances. It can be preferably used for members such as various cabinets, microwave oven containers and golf tees.

Multilayer films containing glycolic acid copolymers include, for example, food packaging materials such as meat, seafood, dairy products, pickles, miso, confectionery, tea and coffee, noodles, cooked rice, and toiletry packaging. It can be preferably used for materials, medicine packaging materials and the like. Furthermore, it can be preferably used as a packaging material for articles requiring treatment under high temperature and high humidity such as retort sterilization, articles requiring special long-term storage, and articles requiring a reduction in environmental load.
Foams containing glycolic acid copolymers include, for example, lunch boxes, tableware, containers for lunch boxes and side dishes, cup noodles and cups for beverages, fresh fish, meat, fruits and vegetables, tofu, It can be preferably used as a container or tray for foodstuffs such as natto and prepared foods, or a disposable food container, a cushioning material, a light shielding material, a heat insulating material, a soundproofing material and the like.

Hollow containers or multi-layer hollow containers containing glycolic acid copolymers include carbonated beverages, soft drinks, drinking water, fruit juice, beer and alcoholic beverages, edible oils, detergents, cosmetic containers, toiletry containers, and gasoline. Containers, seasoning containers that require high-temperature sterilization, baby bottles, etc., articles that require treatment under high temperature and high humidity such as retort sterilization, articles that require long-term storage, articles that require gas barrier properties, and reduced environmental impact. It can be preferably used as a packaging container for required articles and the like.
As the fiber, for example, a fishing line, a fishing net, a nonwoven fabric, a suture, or the like can be used.
The properties of the glycolic acid copolymer of the present invention are measured by the following methods.

(1) Content of monomer units constituting glycolic acid copolymer (1-1) Using a high performance liquid chromatography (HPLC) analyzer, the content of diglycolic acid units is determined under the following conditions.
Specifically, after finely pulverizing, 5 g of a glycolic acid copolymer dried at 80 ° C. and 1 × 10 ² Pa for 6 hours was weighed, and hydrolyzed at room temperature with 20 ml of 8N-NaOH aqueous solution 10 ml for 48 hours, An aqueous solution made acidic with 12.5 ml of a concentrated hydrochloric acid aqueous solution is used as a sample solution.
A sample aqueous solution was prepared using a 0.75 mass% aqueous solution of phosphoric acid as an eluent under the conditions of a column temperature of 40 ° C. and an eluent flow rate of 1 ml / min. -811 connected in series), and the absorbance of a peak corresponding to the corresponding diglycolic acid detected by a UV detector (wavelength 210 nm) is measured.
The content of the diglycolic acid unit present in the polymer is calculated using the calibration curve of diglycolic acid separately prepared and the content of the diglycolic acid unit present based on the weight of the dried and weighed resin. It is calculated based on the molar content of diglycolic acid in 1 g of the dry resin.

(1-2) Content ratio of monomer units other than the diglycolic acid unit constituting the glycolic acid copolymer: 1 ml of 30 mg of the glycolic acid copolymer dried at 80 ° C. and 1 × 10 ² Pa for 6 hours. A measurement sample is prepared by adding a very small amount of tetramethylsilane as a reference substance to a deuterated hexafluoroisopropanol solution of a glycolic acid copolymer dissolved in a deuterated hexafluoroisopropanol solvent in a proportion. Using this measurement sample, ¹ H-NMR measurement at 400 MHz (α-400, manufactured by JASCO Corporation) was performed at an integration number of 500 times, and the obtained result was analyzed and the monomer units other than the diglycolic acid unit were analyzed. The constituent amount is calculated by a molar ratio.

Next, the molar amount of diglycolic acid contained in 1 g of the glycolic acid copolymer obtained in (1-1) and (1-2), and the diglycolic acid constituting the glycolic acid copolymer As a result of the constitutional molar ratios of the compound units other than the above, the content of each compound unit constituting 1 g of the dried resin is calculated in mol% by calculation using the formula weight of each compound unit. Here, the terminal structure can be ignored since the copolymer of the present invention has a sufficiently high molecular weight. Therefore, the calculation is performed assuming that the copolymer consists of only the copolymer compound unit.
The above method is a commonly used calculation method, and the calculation method will be exemplified below.
The glycolic acid copolymer (Y) is composed of a glycolic acid unit, a single hydroxycarboxylic acid unit other than glycolic acid, a diglycolic acid unit, and a single polyol unit. Is α1, the formula weight of a single hydroxycarboxylic acid unit other than glycolic acid is β1, the formula weight of a diglycolic acid unit is γ1, and the formula weight of a single polyol unit is δ1.

The number of moles of the diglycolic acid unit determined in (1-1) above is M01 mole, the glycolic acid unit determined in (1-2) above, a single hydroxycarboxylic acid unit other than glycolic acid, And the molar ratio of a single polyol unit is M1, M2, M3, respectively.
The weight [Z] (g) excluding the diglycolic acid unit in 1 g of the glycolic acid copolymer (Y) is represented by the following formula.
Z = 1− (γ1 × M01)

The average formula weight (MA) of the compound units excluding the diglycolic acid unit in [Z] of the glycolic acid copolymer (Y) is represented by the following formula.
MA = (α1 × M1 + β1 × M2 + δ1 × M3) / (M1 + M2 + M3)
Accordingly, the number of moles of the glycolic acid unit in [Z] of the glycolic acid polymer (Y) [M11], the number of moles of the single hydroxycarboxylic acid unit other than the glycolic acid unit [M21], The number of moles [M31] of the polyol unit is represented by the following formula.
M11 = (Z / MA) × M1 / (M1 + M2 + M3)
M21 = (Z / MA) × M2 / (M1 + M2 + M3)
M31 = (Z / MA) × M3 / (M1 + M2 + M3)
The obtained M11, M21, M01, and M31 are each composed of a glycolic acid unit, a single hydroxycarboxylic acid unit other than glycolic acid, a diglycolic acid unit, and a single polyol unit contained in 1 g of the copolymer. Using the number of moles, the content of each compound unit is calculated.

(2) Average chain length of hydroxycarboxylic acid units other than glycolic acid units Deuterated hexafluoroisopropanol in a ratio of 1 ml to 30 mg of glycolic acid copolymer dried at 80 ° C. and 1 × 10 ² Pa for 6 hours. A measurement sample is prepared by adding a very small amount of tetramethylsilane as a reference substance to a deuterated hexafluoroisopropanol solution of a glycolic acid copolymer dissolved in a solvent. The sample is subjected to ¹³ C-NMR measurement under a complete proton decoupling condition in which the nuclear Overhauser effect has been eliminated under the condition of 10,000 times of integration using an α-400 manufactured by JASCO Corporation as a measuring device.

The obtained integrated value of the peak of the carbonyl group derived from two chains in which the hydroxycarboxylic acid units other than the glycolic acid unit are adjacent to each other is α, and the hydroxycarboxylic acid unit other than the glycolic acid unit and the glycolic acid unit are adjacent to each other. The integrated value of the peak value of the carbonyl group derived from the two chains and the integrated value of the peak value of the carbonyl group derived from the two chains in which the hydroxycarboxylic acid unit other than the glycolic acid unit and the unit structure other than the hydroxycarboxylic acid unit are adjacent to each other. Assuming that the sum is β, the average chain length γ is obtained by Expression (9).

(3) Weight average molecular weight of glycolic acid copolymer It is determined under the following conditions using a gel permeation chromatography (GPC) analyzer 8020 GPC system manufactured by Tosoh Corporation.
As a solvent to be used, hexafluoroisopropanol in which 80 mM sodium trifluoroacetate (a reagent manufactured by Wako Pure Chemical Industries, Ltd.) is dissolved is prepared in advance. That is, a solution in which 6.48 g of sodium trifluoroacetate is dissolved in 1000 g of hexafluoroisopropanol is prepared (hereinafter, abbreviated as eluent).
As a sample solution of the glycolic acid copolymer for evaluation, 20 mg of the glycolic acid copolymer dried at 80 ° C. and 1 × 10 ² Pa for 6 hours was precisely weighed, dissolved in 3 g of the eluent, and then 0.2 μm Use what was filtered with the filter of.

At a column temperature of 40 ° C., the eluent was subjected to a column under the condition of a flow rate of 1 ml / min [column configuration was Tsquadcolumn HHR-H (registered trademark) manufactured by Tosoh Corporation as a guard column, and Tskgel (trade name manufactured by Tosoh Corporation) was used. (Registered trademark) G5000HHR and Tskgel (registered trademark) G3000HHR (manufactured by Tosoh Corporation) in series, each having a molecular weight of 1,577,000, 685,000, 333,000, 100,250,62. , 600, 24, 300, 12, 700, 4, 700, 1, 680, 1140 monodisperse polymethyl methacrylate standard materials from Polymer Laboratories of known molecular weight and RI detection of methyl methacrylate monomer (molecular weight 100) A calibration curve obtained from the elution time To calculate the weight average molecular weight from elution time.

(4) Melting point of glycolic acid copolymer Determined according to JIS K7121.
Using DSC-7 manufactured by Perkin-Elmer Co., Ltd., the glycolic acid copolymer dried at 80 ° C. and 1 × 10 ² Pa for 6 hours was heated from −20 ° C. to 250 ° C. at a rate of 10 ° C./min. From the DSC curve obtained. At this time, when there are a plurality of melting peaks, the peak top temperature of the highest temperature peak among the melting peaks is defined as the melting point.

(5) Melt heat stability of copolymer 7.5 g of a glycolic acid copolymer sample was charged into a flask equipped with a stirring blade, the system was replaced with dry nitrogen at room temperature, and then the mixture was gently stirred. While drying, vacuum drying is performed at 80 ° C. and 1 × 10 ² Pa for 6 hours. After the drying is completed, the inside of the system is brought to normal pressure with dry nitrogen, and the temperature is raised to 240 ° C. while stirring is continued to melt the glycolic acid copolymer. After reaching 235 ° C., sample 5 minutes later. Evaluation of the degree of coloration of the glycolic acid copolymer obtained by sampling is performed according to the following procedure.

In the method described in the above (3), a UV detector (UV8020 manufactured by Tosoh Corporation) set at a wavelength of 350 nm is connected as a detector, and the evaluation is performed based on the total number of detected counts.
The lower the total count, the better the color tone of the glycolic acid copolymer. The total count number and the visual color tone of the glycolic acid copolymer correspond as follows.
When the count is less than 50, the glycolic acid copolymer is white to pale yellow. When the count is 50 or more and 100 or less, the copolymer is yellow. When the count is more than 100, the copolymer is yellow. The polymers correspond to brown to dark brown.

(6) Evaluation of gas barrier properties of melt-formed sheet [Preparation of melt-formed sheet]
The glycolic acid copolymer is dried for about 2 hours in a nitrogen circulating thermostatic dryer set at 130 ° C. until the water content becomes 200 ppm or less. Next, the sheet is heated and pressurized for 5 minutes by a heating press set at 240 ° C., and cooled by a cooling press set at 25 ° C. to obtain a sheet having a thickness of 200 μm.

[Evaluation of gas barrier properties]
The gas barrier property is measured by measuring the oxygen gas permeability using the above-mentioned melt-formed sheet as a sample.
The oxygen gas permeability is measured by using an oxygen permeability measuring device OX-TRAN200H manufactured by mocon as a measuring device in accordance with JIS K7126B method. That is, a sheet having a thickness of 200 μm is cut into a square shape having a side of 120 mm, and a test is performed under the conditions of a temperature of 23 ° C. and a relative humidity of 65%. The value of the oxygen gas permeability is represented by a value (cc / m ² · day · atm) converted to a thickness of 10 µm using a value at which the oxygen gas permeability of the sample is an equilibrium value.
The gas barrier property indicates that the lower the oxygen gas permeability, the higher the gas barrier property.
When the oxygen gas permeability is 10 or less, the gas barrier property is extremely high. When the permeability exceeds 10 and is 20 or less, the gas barrier property is high, and when the oxygen gas permeability is 20 or more. Indicates that the gas barrier property is low.

(7) Evaluation of mechanical properties of melt-formed sheet [Production of melt-formed sheet]
The glycolic acid copolymer is dried in a nitrogen circulating thermostatic dryer set at 130 ° C. for about 2 hours until the water content becomes 200 ppm or less. Next, the sheet is heated and pressed by a heating press set at 240 ° C. for 5 minutes, and cooled by a cooling press set at 25 ° C. to obtain a sheet having a thickness of 200 μm.

[Strength of melt-formed sheet]
The above-mentioned sheet having a thickness of about 200 μm is cut into a square having a side of 100 mm, and the following test is performed under the conditions of a temperature of 23 ° C. and a relative humidity of 65%.
The opposite sides are sandwiched by a metal jig so that the width of the sheet to be sandwiched is 100 mm and the depth of the sheet to be sandwiched is 10 mm, and the jigs are 90 degrees with respect to the line symmetry center line of the sheet on the opposite side to which the jig is attached. Bend the sheet until it makes an angle. This operation is performed up to five times in the same direction based on the center line of the sheet. The strength of the sheet indicates the number of times of bending when the sheet is broken as a numerical value. If the sheet is not damaged by the test up to 5 times, it shall be 5 or more.
When the strength of the sheet is 3 or less, the mechanical strength required for molded articles such as containers and films is insufficient, and when the strength is 4 or more, the mechanical strength required for molded articles such as containers and films is insufficient. To have.

(8) Evaluation of disintegration property in soil of melt-formed sheet Since biodegradability can be evaluated by a disintegration test in soil, the evaluation is performed according to the following procedure.
The sheet prepared by the method described in the above (7) [Production of a melt-formed sheet] is cut into a strip having a length of 30 mm and a width of 100 mm, buried in the soil of the field at a depth of about 10 cm, and every three months Dig into to check its shape. The time when the shape starts to collapse is observed, and the case where the collapse starts within 12 months is evaluated as having soil collapse property.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but these Examples do not limit the scope of the present invention.

[Example 1]
(A) Production of low molecular weight glycolic acid copolymer
In a Pyrex (registered trademark) glass separable flask with a baffle plate having an inner volume of 350 ml and equipped with a distilling tube and a flat blade type stirring blade, the content of diglycolic acid is 0.005 mol% or less based on glycolic acid. 332 g of a 70% by mass aqueous solution of glycolic acid, 58 g of a 90% by mass aqueous solution of L-lactic acid, and 0.05% by mass of tetraisopropoxygermanium with respect to the raw material aqueous solution (2.2 × 10 ⁻⁶ as germanium metal atoms per gram of monomer) Mol), nitrogen replacement was performed.
Since the molar ratio of diglycolic acid units in the charged raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.84, and the converted molar ratio of lactic acid units is 0.16. is there.

Thereafter, the separable flask was immersed in an oil bath at a temperature of 150 ° C., and the stirring was performed at 200 rpm for 1.5 hours under a nitrogen stream to perform dehydration. Then, while the oil bath temperature of 0.99 ° C., 1 hour at 5.0 × ¹⁰ 4 Pa, 0.5 hours at 2.5 × ¹⁰ 4 Pa, 50 minutes 1.0 × ¹⁰ 4 Pa, 5.0 The polycondensation reaction was carried out at × 10 ³ Pa for 50 minutes and at 2.0 × 10 ³ Pa for 50 minutes. During this time, the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed a substantially constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa [Step (A)]. After the completion of this step, the molecular weight of the glycolic acid copolymer was measured by sampling a small amount, and as a result, the weight average molecular weight was 1,900.

The reaction temperature was gradually raised to 190 ° C. over 25 minutes while maintaining the stirring rotation speed and the reduced pressure [Step (B)]. As a result of sampling a small amount of the molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C., the weight average molecular weight was 2,100.
Subsequently, the reaction temperature was raised to 200 ° C. in 10 minutes, the stirring speed was changed to 600 rpm, and the total reaction time after exceeding 190 ° C. at a reduced pressure of 4.0 × 10 ² Pa was obtained. The reaction was continued for 2.5 hours to obtain a glycolic acid copolymer having a weight average molecular weight of 13,800 [Step (C)]. At this time, the time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 100 minutes based on the time when the temperature of the reaction solution exceeded 190 ° C. The increase in the weight average molecular weight per hour was 4,740.
The obtained glycolic acid copolymer in a molten state was cooled and solidified, taken out, and subsequently, the obtained glycolic acid copolymer was polymerized by the following operation.

(B) Melt polycondensation of glycolic acid copolymer 25 g of the above-obtained glycolic acid copolymer was charged into a Pyrex (registered trademark) glass cylindrical tube having an inner diameter of 70 mm and an effective length of 250 mm, and a surface heater for heating was used. Was set in a glass tube oven (GTO-350RG manufactured by Shibata Kagaku KK) having After replacing the inside with nitrogen at room temperature, the rotation of the inside cylindrical tube was started, the reaction temperature was raised to 200 ° C., the melt polycondensation was performed at a pressure of 2.6 × 10 Pa for 12 hours, and then dry nitrogen was added. , And cooled and solidified to take out the contents.
(C) Analysis value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 123,000, and the copolymer composition was 83.97 mol% of glycolic acid units and 0.03 of diglycolic acid units. It contained 16.00 mol% of a lactic acid unit as a hydroxycarboxylic acid unit other than a glycolic acid unit, and had an average chain length of 1.08 and a coloring degree of 28.

(D) Evaluation of Glycolic Acid Copolymer and Melt Molded Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 36, which was almost good. Further, the oxygen gas permeability of the melt-molded sheet was 9.1 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 4, which had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 1 shows the analysis values and the evaluation results.

[Example 2]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 40.83 g of a 90% by mass aqueous solution of L-lactic acid, and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) was charged to the raw material aqueous solution (the molar ratio of diglycolic acid units in the raw material was 0%). 0.00005 or less, the converted molar ratio was 0, the converted molar ratio of glycolic acid units was 0.89, and the converted molar ratio of lactic acid units was 0.11). Similarly, the polycondensation operation of [Steps (A), (B) and (C)] was performed to produce a glycolic acid copolymer having a weight average molecular weight of 13,800. In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after [Step (A)] was completed was 1,900, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. was 2,100. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 100 minutes based on the point in time at which the temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 4,740.
The obtained glycolic acid copolymer in a molten state was cooled and solidified, taken out, and subsequently, the obtained glycolic acid copolymer was polymerized by the following operation.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid-phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, pulverization treatment Pyrex with an inner diameter of 70 mm and an effective length of 250 mm (registered) (Trademark) 35 g of the glycolic acid copolymer obtained above was charged into a glass cylindrical tube, and set in a glass tube oven (GTO-350RG manufactured by Shibata Kagaku Co., Ltd.) having a surface heater for heating. After the inside was replaced with nitrogen under room temperature conditions, rotation of the inside cylindrical tube was started, and melt polycondensation was performed at a reaction temperature of 200 ° C. and a pressure of 2.6 × 10 Pa for 3.5 hours, followed by dry nitrogen. It was cooled to room temperature under normal pressure.

Subsequently, while continuing rotation of the Pyrex (registered trademark) glass cylindrical tube, crystallization was carried out at 130 ° C. for 5 hours under dry nitrogen conditions, followed by cooling and solidification to obtain a crystallized weight average molecular weight of 43. , 200 glycolic acid copolymers.
The obtained glycolic acid copolymer is pulverized and sieved to obtain a pulverized crystallized glycolic acid copolymer having a particle size of 100 to 300 μm (hereinafter abbreviated as crystallized glycolic acid copolymer P-1). Was. The melting point of the crystallized glycolic acid copolymer P-1 was 185 ° C.
Subsequently, a solid-phase polymerization reaction was performed according to the following procedure.

(B-2) Solid-phase polymerization of crystallized glycolic acid copolymer A cylindrical SUS316 vertical reactor having an inner diameter of 40 mm and an effective length of 50 mm was charged with 25 g of the pulverized crystallized glycolic acid copolymer A, and the reaction pressure was increased. At 1.013 × 10 ⁵ Pa (normal pressure), a nitrogen gas having a flow rate of 30 NL / min (measured value at 25 ° C.) and a dew point temperature of −95 ° C. was heated to 170 ° C. and allowed to flow. Allowed to react for hours.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 186,000, and the copolymer composition was 88.97 mol% of glycolic acid units and 0.03 of diglycolic acid units. It contained 11.00 mol% of lactic acid units as hydroxycarboxylic acid units other than glycolic acid units, and the average chain length of the lactic acid units was 1.02 and the degree of coloring was 29.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 38, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 8.0 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 1 shows the analysis values and the evaluation results.

[Example 3]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 21 g of a 90% by mass aqueous solution of L-lactic acid, and a raw material aqueous solution Of tetraisopropoxygermanium (2.3 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) based on the weight of the starting material (the molar ratio of diglycolic acid units in the charged raw material is 0.00005 or less) Therefore, the conversion molar ratio is 0, the conversion molar ratio of the glycolic acid unit is 0.94, and the conversion molar ratio of the lactic acid unit is 0.06. )]. In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. After the completion of this step, the molecular weight of the glycolic acid copolymer was measured by sampling a small amount, and as a result, the weight average molecular weight was 1,900.

Thereafter, the temperature was gradually raised to a reaction temperature of 190 ° C. over 25 minutes while maintaining the stirring rotation speed and the reduced pressure [Step (B)]. As a result of sampling a small amount of the molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C., the weight average molecular weight was 2,100.
Subsequently, the reaction temperature was raised to 225 ° C. in 20 minutes, the stirring speed was changed to 600 rpm, and the total reaction time after exceeding 190 ° C. at a reduced pressure of 4.0 × 10 ² Pa was 2 The reaction was continued for 0.5 hours to obtain a glycolic acid copolymer having a weight average molecular weight of 16,300 [Step (C)]. At this time, the time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 80 minutes based on the time when the temperature of the reaction solution exceeded 190 ° C. The increase in the weight average molecular weight per hour was 5,925.
The obtained glycolic acid copolymer in a molten state was cooled and solidified, taken out, and subsequently, the obtained glycolic acid copolymer was polymerized by the following operation.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, pulverization treatment The obtained glycolic acid copolymer is reacted. Except that the temperature was set to 225 ° C., melt polycondensation, crystallization treatment, and pulverization treatment were performed to crystallize in the same manner as in Example 2 (b-1), and the weight average molecular weight was 46,300 and the melting point was 209. C., a glycolic acid copolymer (hereinafter abbreviated as crystallized glycolic acid copolymer P-2) was produced.
Subsequently, a solid-phase polymerization reaction was performed according to the following procedure.
(B-2) Solid-phase polymerization of crystallized glycolic acid copolymer Using the obtained crystallized glycolic acid copolymer P-2, solid-phase polymerization was performed in the same manner as in Example 2 (b-2). Carried out.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 182,000, and the copolymer composition was 93.97 mol% of glycolic acid units and 0.1 g of diglycolic acid units. 03 mol%, 6.00 mol% of a lactic acid unit was contained as a hydroxycarboxylic acid unit other than the glycolic acid unit, and the average chain length of the lactic acid unit was 1.02 and the degree of coloring was 29.

(D) Evaluation of Glycolic Acid Copolymer and Melt Molded Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 43, which was almost good. Further, the oxygen gas permeability of the melt-molded sheet was 7.2 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 1 shows the analysis values and the evaluation results.

[Example 4]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 338 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 51 g of 6-hydroxyhexanoic acid, and a raw material aqueous solution In addition, stannous chloride (2.1 × 10 ⁻⁶ mol as tin metal atom per 1 g of monomer) of 0.03% by mass was charged (the molar ratio of diglycolic acid units in the charged raw material was 0.00005). Therefore, the conversion molar ratio was 0, the conversion molar ratio of glycolic acid units was 0.89, and the conversion molar ratio of 6-hydroxyhexanoic acid units was 0.11. The polycondensation operation of [Steps (A), (B) and (C)] was carried out in the same manner as in the above to produce a glycolic acid copolymer having a weight average molecular weight of 13,000.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after [Step (A)] was completed was 1,900, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. was 2,100. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 105 minutes based on the point in time at which the temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 4,514.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. 2 (b-1), a glycolic acid copolymer having a weight average molecular weight of 42,900 and a melting point of 183 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in 2 (b-1) Crystallized glycolic acid copolymer P-3) was prepared.
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-3, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analysis value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 167,000, and the copolymer composition was 88.97 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, containing 11.00 mol% of 6-hydroxyhexanoic acid units, which are hydroxycarboxylic acid units other than glycolic acid units, the average chain length of the 6-hydroxyhexanoic acid units is 1.03, Was 29.

(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 38, which was almost good. In addition, the oxygen gas permeability of the melt-formed sheet was 8.1 (cc / m ² · day · atm), and had high gas barrier properties. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 1 shows the analysis values and the evaluation results.

[Example 5]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 338 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 30 g of 3-hydroxybutyric acid, and an aqueous solution of raw material were used. On the other hand, 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) was charged (the molar ratio of diglycolic acid units in the charged raw material was 0.00005 or less. Therefore, the conversion molar ratio was 0, the conversion molar ratio of glycolic acid units was 0.89, and the conversion molar ratio of 3-hydroxybutyric acid units was 0.11, except that in Example 2). The polycondensation operation of [Steps (A), (B) and (C)] was performed to produce a glycolic acid copolymer having a weight average molecular weight of 13,700.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after [Step (A)] was completed was 1,900, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. was 2,100. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 100 minutes based on the point in time at which the temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 4,740.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. 2 (b-1), a glycolic acid copolymer having a weight average molecular weight of 43,000 and a melting point of 184 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment (hereinafter referred to as crystallization). Glycolic acid copolymer P-4).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-4, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analysis value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 179,000, and the copolymer composition was 88.97 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, containing 11.00 mol% of 3-hydroxybutyric acid units which are hydroxycarboxylic acid units other than glycolic acid units, the average chain length of the 3-hydroxybutyric acid units is 1.02, and the degree of coloring is 28. Met.

(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 39, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 8.0 (cc / m ² · day · atm), and had high gas barrier properties. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 1 shows the analysis values and the evaluation results.

[Comparative Example 1]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 40.83 g of a 90% by mass aqueous solution of L-lactic acid, and After charging 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) to the raw material aqueous solution, nitrogen substitution was performed.

Since the molar ratio of diglycolic acid units in the charged raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.89, and the converted molar ratio of lactic acid units is 0.11. is there.
Thereafter, the separable flask was immersed in an oil bath at a temperature of 150 ° C., and the stirring was performed at 200 rpm for 1.5 hours under a nitrogen stream to perform dehydration. The polycondensation reaction was carried out at 5.0 × 10 ⁴ Pa for 1 hour, at 2.5 × 10 ⁴ Pa for 0.5 hour, and at 1.0 × 10 ⁴ Pa for 20 minutes while keeping the oil bath temperature at 150 ° C. . During this time, the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed a substantially constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa.

After completion of this step, a small amount of the molecular weight of the glycolic acid copolymer was sampled and measured. As a result, the weight average molecular weight was 400. Thereafter, the temperature was gradually raised to a reaction temperature of 190 ° C. over 25 minutes while maintaining the stirring rotation speed and the reduced pressure state. As a result of sampling and measuring a small amount of the molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C., the weight average molecular weight was 600.
Subsequently, the reaction temperature was raised to 200 ° C. in 10 minutes, the stirring speed was changed to 600 rpm, and the total reaction time after exceeding 190 ° C. at a reduced pressure of 4.0 × 10 ² Pa was obtained. The reaction was continued for 2.5 hours to obtain a glycolic acid copolymer having a weight average molecular weight of 12,200.
At this time, the time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 120 minutes based on the time when the temperature of the reaction solution exceeded 190 ° C. The increase in the weight average molecular weight per hour was 4,700.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. In the same manner as in 2 (b-1), a glycolic acid copolymer having a weight average molecular weight of 43,800 and a melting point of 183 ° C. crystallized by melt polycondensation, crystallization and pulverization (hereinafter referred to as crystallization) Glycolic acid copolymer P-5).
(B-2) Solid-phase polymerization of crystallized glycolic acid copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-5, solid-phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the glycolic acid copolymer obtained after the solid phase polymerization was 109,000, and the composition was 88.86 mol% of glycolic acid units, and diglycolic acid. The unit contained 0.13 mol% of lactic acid units as hydroxycarboxylic acid units other than glycolic acid units, and the average chain length of lactic acid units was 1.02 and the degree of coloring was 34.

(D) Evaluation of glycolic acid copolymer and melt-molded sheet The melt-molded sheet had an oxygen gas permeability of 8.2 (cc / m ² · day · atm) and had good gas barrier properties. The strength of the melt-formed sheet was 4, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil. As a result of evaluating the melt heat stability of the glycolic acid copolymer, the degree of coloring was 175 and the color changed to brown.
Table 2 shows the analysis values and the evaluation results.

[Comparative Example 2]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 10.2 g of a 90% by mass aqueous solution of L-lactic acid, and To the raw material aqueous solution, 0.05% by mass of tetraisopropoxygermanium (2.3 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) was charged (the molar ratio of diglycolic acid units in the raw material was 0%). 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of the glycolic acid unit is 0.97, and the converted molar ratio of the lactic acid unit is 0.03. (A), (B) and (C)] to produce a glycolic acid copolymer having a weight average molecular weight of 16,300.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after [Step (A)] was completed was 1,900, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. was 2,100. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 80 minutes based on the time when the temperature exceeded 190 ° C. Thus, the increase in the weight average molecular weight per hour in this time range was 5,925.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, pulverization treatment The obtained glycolic acid copolymer is reacted. Melt polycondensation, crystallization treatment, and pulverization treatment were performed in the same manner as in Example 2 (b-1) except that the temperature was 230 ° C., and the crystallized weight average molecular weight was 46,300 and the melting point was 225. C., a glycolic acid copolymer (hereinafter abbreviated as crystallized glycolic acid copolymer P-6) was prepared.
Subsequently, a solid-phase polymerization reaction was performed according to the following procedure.
(B-2) Solid-phase polymerization of crystallized glycolic acid copolymer Using the obtained crystallized glycolic acid copolymer P-6, solid-phase polymerization was performed in the same manner as in Example 2 (b-2). Carried out.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 164,000, and the copolymer composition was 96.97 mol% of glycolic acid units and 0.03 of diglycolic acid units. The lactic acid unit contained 3.00 mol% as a hydroxycarboxylic acid unit other than the glycolic acid unit, and the average chain length of the lactic acid unit was 1.01 and the degree of coloring was 33.

(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet The melt-formed sheet had an oxygen gas permeability of 7.0 (cc / m ² · day · atm), which was an extremely high gas barrier property. In addition, the melt-formed sheet had disintegration properties in soil, and the strength of the melt-formed sheet was 5 or more and had the mechanical strength necessary for molded articles such as containers and films. As a result, the coloring degree changed to brown at 115.
Table 2 shows the analysis values and the evaluation results.

[Comparative Example 3]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 290 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 98.5 g of a 90% by mass aqueous solution of L-lactic acid, and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) was charged to the raw material aqueous solution (the molar ratio of diglycolic acid units in the raw material was 0%). 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.73, and the converted molar ratio of lactic acid units is 0.27. (A), (B) and (C)] to produce a glycolic acid copolymer having a weight average molecular weight of 13,800.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after [Step (A)] was completed was 1,900, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. was 2,100. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 100 minutes based on the point in time at which the temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 4,740.

(B) Melt polycondensation of glycolic acid copolymer Melt polycondensation was carried out in the same manner as described in Example 1 (b).
(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 122,000, and the copolymer composition was such that glycolic acid units were 72.96 mol% and diglycolic acid units were 0.03. The lactic acid unit contained 27.01 mol% as a hydroxycarboxylic acid unit other than the glycolic acid unit, and the average chain length of the lactic acid unit was 1.14 and the coloring degree was 33.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the degree of coloring was 39, the strength of the melt-formed sheet was 4, and containers and films were used. Had the required mechanical strength for the molded article. Further, the melt-formed sheet had disintegration properties in soil, but the oxygen-gas permeability of the melt-formed sheet was 35 (cc / m ² · day · atm) and the gas barrier property was low.
Table 2 shows the analysis values and the evaluation results.

[Comparative Example 4]
(A) Production of low molecular weight glycolic acid copolymer
Glycolic acid and lactic acid were subjected to a polycondensation reaction in separate devices, and two low molecular weight polymers were mixed on the way to carry out the reaction.
(A-1) After charging 60 g of a 90 mass% L-lactic acid aqueous solution to a separable flask made of Pyrex (registered trademark) glass with a baffle plate having an inner volume of 100 ml and having a distilling tube and anchor blades, nitrogen replacement was performed. Was. Thereafter, the separable flask was immersed in an oil bath at a temperature of 130 ° C., and the stirring was performed at 200 rpm for 1.5 hours under a nitrogen stream to perform dehydration. Thereafter, with the reaction temperature kept at 130 ° C., 1 hour at 5.0 × 10 ⁴ Pa, 1 hour at 2.5 × 10 ⁴ Pa, 1 hour at 1.0 × 10 ⁴ Pa, 5.0 × 10 ⁴ Pa ^The polycondensation reaction was performed at ³ Pa for 1 hour and at 2.0 × 10 ³ Pa for 1 hour. Then, the mixture was cooled and solidified to take out a polycondensate. The weight average molecular weight of the amorphous poly-L-lactic acid was 1,000.

(A-2) In the same apparatus as in Example 1 (a), 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, and Then, 0.05% by mass of tetraisopropoxygermanium (2.3 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) was charged and subjected to nitrogen substitution. Thereafter, the separable flask was immersed in an oil bath at a temperature of 150 ° C., and the stirring was performed at 200 rpm for 1.5 hours under a nitrogen stream to perform dehydration.
Thereafter, with the reaction temperature kept at 150 ° C., 5.0 × 10 ⁴ Pa for 1 hour, 2.5 × 10 ⁴ Pa for 0.5 hour, 1.0 × 10 ⁴ Pa for 50 minutes, 5.0 A polycondensation reaction was carried out at × 10 ³ Pa for 50 minutes and at 2.0 × 10 ³ Pa for 50 minutes. After the completion of this step, the molecular weight of the glycolic acid copolymer was measured by sampling a small amount, and as a result, the weight average molecular weight was 1,900. In this step, the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa.

While maintaining the stirring rotation speed and the reduced pressure, the temperature was gradually raised to 190 ° C. in 20 minutes. As a result of sampling and measuring a small amount of the molecular weight of the polymer at a reaction temperature of 190 ° C., the weight average molecular weight was 2,100.
Subsequently, the reaction temperature was raised to 200 ° C. in 10 minutes, and the stirring speed was changed to 450 revolutions per minute. Here, the pressure was released once with nitrogen, 29.4 g of the poly-L-lactic acid prepared in (a-1) was added under nitrogen, and the pressure was reduced again, and the pressure was reduced to 4.0 × 10 4. ^{At 2} Pa, the reaction was continued for 3 hours as a total reaction time after exceeding 190 ° C. to obtain a glycolic acid copolymer having a weight average molecular weight of 11,000. The obtained glycolic acid copolymer in a molten state was taken out after cooling and solidifying, and subsequently, the obtained glycolic acid copolymer was polymerized by the following operation.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. The glycolic acid copolymer having a weight average molecular weight of 42,600 and a melting point of 189 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in 2 (b-1) Glycolic acid copolymer P-7).
(B-2) Solid-phase polymerization of crystallized glycolic acid copolymer Subsequently, solid-phase polymerization was performed in the same manner as in Example 2 (c) using the obtained crystallized glycolic acid copolymer P-7. Carried out.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the glycolic acid copolymer obtained after the solid-phase polymerization was 187,000, and the composition was 88.97 mol% of glycolic acid units and diglycolic acid. It contained 0.03 mol% of a unit and 11.00 mol% of a lactic acid unit as a hydroxycarboxylic acid unit other than the glycolic acid unit. The average chain length of the lactic acid unit was 1.62 and the degree of coloring was 29.
(D) Evaluation of glycolic acid copolymer and melt-molded sheet The oxygen-gas permeability of the melt-molded sheet was 8.4 (cc / m ² · day · atm), indicating that it had good gas barrier properties. The strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil. As a result of evaluating the melting heat stability of the compound, the coloring degree changed to brown at 105.
Table 2 shows the analysis values and the evaluation results.

[Example 6]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 40.83 g of a 90% by mass aqueous solution of L-lactic acid, 0.12 g of pentyl glycol and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as a germanium metal atom per 1 g of monomer) were added to the aqueous solution of the raw material (dimethyl in the raw material). Since the molar ratio of glycolic acid units is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.89, the converted molar ratio of lactic acid units is 0.1097, and the converted molar ratio of neopentyl glycol units is The conversion molar ratio is 0.0003), and the polymerization conditions in [Step (A)] are maintained for 1.5 hours under a nitrogen stream. After dehydration by, while the oil bath temperature of 0.99 ° C., 1 hour at 5.0 × ¹⁰ 4 Pa, 0.5 hours at 2.5 × ¹⁰ 4 Pa, at 1.0 × ¹⁰ 4 Pa Except that the polycondensation reaction was carried out for 50 minutes, 5.0 × 10 ³ Pa for 50 minutes, and 2.0 × 10 ³ Pa for 90 minutes, the same as in Example 1 [Steps (A), (B) and (C)] to produce a glycolic acid copolymer having a weight average molecular weight of 14,400.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after the completion of [Step (A)] is 2,500, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. is 2,700. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 90 minutes based on the point in time at which the temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 4,867.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. The glycolic acid copolymer having a weight average molecular weight of 44,200 and a melting point of 183 ° C. crystallized by performing melt polycondensation, crystallization treatment, and pulverization treatment in the same manner as in 2 (b-1). Glycolic acid copolymer P-8).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-8, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 187,000, and the copolymer composition was 88.94 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, 10.99 mol% of lactic acid units, which are hydroxycarboxylic acid units other than glycolic acid units, and 0.04 mol% of neopentylglycol units. there were.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 39, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 8.3 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 3 shows the analysis values and the evaluation results.

[Example 7]
(A) Production of low molecular weight glycolic acid copolymer
In the same device as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 40.83 g of a 90% by mass aqueous solution of L-lactic acid, 1 0.136 g of 2,6-hexanediol and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol of germanium metal atom per gram of monomer) with respect to the aqueous solution of the raw material (raw material) Since the molar ratio of the diglycolic acid unit is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of the glycolic acid unit is 0.89, the converted molar ratio of the lactic acid unit is 0.1097, and neopentyl. The weight of [Steps (A), (B) and (C)] was the same as in Example 6 except that the conversion molar ratio of glycol units was 0.0003.) It was prepared glycolic acid copolymer having a weight average molecular weight 14,400 perform focus operation.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after the completion of [Step (A)] is 2,500, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. is 2,700. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 90 minutes based on the point in time at which the temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 4,867.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. The glycolic acid copolymer having a weight average molecular weight of 43,800 and a melting point of 183 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in 2 (b-1) Abbreviated as glycolated glycolic acid copolymer P-9).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-9, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 187,000, and the copolymer composition was 88.94 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, 10.99 mol% of lactic acid units, which are hydroxycarboxylic acid units other than glycolic acid units, and 0.04 mol% of 1,6-hexanediol units, the average chain length of lactic acid units is 1.01, and the degree of coloring Was 33.
(D) Evaluation of Glycolic Acid Copolymer and Melt Molded Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 43, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 8.2 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 3 shows the analysis values and the evaluation results.

Example 8
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 40.83 g of a 90% by mass aqueous solution of L-lactic acid, and 0.04 g of methylolpropane and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per gram of monomer) were charged to the raw material aqueous solution (diglycol in the raw material charged). Since the molar ratio of the acid unit is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of the glycolic acid unit is 0.8903, the converted molar ratio of the lactic acid unit is 0.10962, and the converted amount of the trimethylolpropane unit is Except that the molar ratio is 0.00008). [Steps (A), (B) and (C)] It was prepared glycolic acid copolymer having a weight average molecular weight 15,600 perform condensation operation.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after completion of [Step (A)] is 2,700, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. is 2,900. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 85 minutes based on the point in time at which the temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 5,012.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. In the same manner as in 2 (b-1), a glycolic acid copolymer having a weight-average molecular weight of 46,500 and a melting point of 184 ° C. crystallized by melt polycondensation, crystallization and pulverization (hereinafter referred to as “crystal”) Glycolic acid copolymer P-10).
(B-2) Solid-phase polymerization of crystallized glycolic acid copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-10, solid-phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 325,000, and the copolymer composition was 88.98 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, 10.98 mol% of lactic acid units, which are hydroxycarboxylic acid units other than glycolic acid units, and 0.01 mol% of trimethylolpropane units. The average chain length of lactic acid units was 1.01, and the degree of coloring was 34. there were.
(D) Evaluation of glycolic acid copolymer and melt-molded sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 44, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 8.3 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 3 shows the analysis values and the evaluation results.

[Example 9]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 40.83 g of a 90% by mass aqueous solution of L-lactic acid, 0.12 g of pentyl glycol, 0.04 g of trimethylolpropane, and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol of germanium metal atom per 1 g of monomer) were charged based on the aqueous solution of the raw material. (Since the molar ratio of diglycolic acid units in the raw materials is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.89, and the converted molar ratio of lactic acid units is 0.1. 1096, the converted molar ratio of neopentyl glycol units is 0.00032, and the converted molar ratio of trimethylolpropane units is 0.00008) except that the polycondensation operation of [Steps (A), (B) and (C)] was carried out in the same manner as in Example 6 to produce a glycolic acid copolymer having a weight average molecular weight of 16,000. did.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after completion of [Step (A)] is 2,900, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. is 3,100. The time required for the weight-average molecular weight of the glycolic acid copolymer to reach 10,000 was 80 minutes based on the point at which the temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 5,175.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. In the same manner as in 2 (b-1), a glycolic acid copolymer having a weight average molecular weight of 47,300 and a melting point of 184 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment (hereinafter referred to as “crystal”) Glycolic acid copolymer P-11).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-11, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical values of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 330,000, and the copolymer composition was 88.94 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, 10.98 mol% of lactic acid units which are hydroxycarboxylic acid units other than glycolic acid units, 0.04 mol% of neopentylglycol units, and 0.01 mol% of trimethylolpropane units, and the average chain length of lactic acid units. Was 1.01 and the degree of coloring was 33.
(D) Evaluation of glycolic acid copolymer and melt-molded sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 44, which was almost good. In addition, the oxygen gas permeability of the melt-formed sheet was 8.6 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 3 shows the analysis values and the evaluation results.

[Example 10]
(A) Production of glycolic acid copolymer
Using the glycolic acid copolymer having a weight average molecular weight of 16,000 obtained in (a) of Example 9 and performing melt polycondensation in the same manner as in Example 1 (b), A coalescence was produced.
(B) Analysis value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 163,000, and the copolymer composition was 88.97 mol% of glycolic acid units and 0.04 of diglycolic acid units. Mol%, 10.94 mol% of lactic acid units which are hydroxycarboxylic acid units other than glycolic acid units, 0.04 mol% of neopentylglycol units, and 0.01 mol% of trimethylolpropane units, and the average chain length of lactic acid units. Was 1.01 and the degree of coloring was 39.

(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 48, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 8.7 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 3 shows the analysis values and the evaluation results.

[Example 11]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous glycolic acid solution containing 0.01 mol% of diglycolic acid content with respect to glycolic acid, 40.83 g of a 90% by mass aqueous L-lactic acid solution, 0.12 g of neopentyl glycol and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) were charged based on the aqueous solution of the raw material (glycol in the raw material charged). The converted molar ratio of the acid unit is 0.89, the converted molar ratio of the lactic acid unit is 0.10957, the converted molar ratio of the neopentyl glycol unit is 0.00034, and the converted molar ratio of the diglycolic acid unit is 0.00009. Other than that, the polycondensation operation of [Steps (A), (B) and (C)] was carried out in the same manner as in Example 6 to obtain a weight average molecular weight of 14 It was prepared glycolic acid copolymer 300.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after the completion of [Step (A)] is 2,500, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. is 2,700. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 90 minutes based on the point in time at which the temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 4,867.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. 2 (b-1), a glycolic acid copolymer having a weight average molecular weight of 44,100 and a melting point of 184 ° C. (hereinafter referred to as crystal Glycolic acid copolymer P-12).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-12, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 186,000, and the copolymer composition was 88.96 mol% of glycolic acid units and 0.04 of diglycolic acid units. The average chain length of the lactic acid unit was 10.96 mol%, the lactic acid unit was 0.096 mol%, and the coloring degree was 29.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 40, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 8.5 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 4 shows the analysis values and the evaluation results.

[Example 12]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 40.83 g of a 90% by mass aqueous solution of L-lactic acid, 0.12 g of pentyl glycol, 0.02 g of oxalic acid, and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) were charged based on the aqueous solution of the raw material. (Since the molar ratio of diglycolic acid units in the charged raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.89, and the converted molar ratio of lactic acid units is 0.1096. , The converted molar ratio of neopentyl glycol units is 0.00034, and the converted molar ratio of oxalic acid units is 0.00006.) Outside, in the same manner as in Example 6 [Step (A), (B) and (C)] was prepared polycondensation operation was carried out weight-average molecular weight glycolic acid copolymer of 14,300 in.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after the completion of [Step (A)] is 2,500, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. is 2,700. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 90 minutes based on the point in time at which the temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 4,867.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. The glycolic acid copolymer having a weight average molecular weight of 44,200 and a melting point of 184 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in 2 (b-1) Glycolic acid copolymer P-13).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-13, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 185,000, and the copolymer composition was 88.96 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, 10.96 mol% of lactic acid units, which are hydroxycarboxylic acid units other than glycolic acid units, 0.04 mol% of neopentylglycol units, and 0.01 mol% of oxalic acid units. The average chain length of lactic acid units is 1.01 and the coloring degree was 28.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 39, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 8.5 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 4 shows the analysis values and the evaluation results.

Example 13
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 365 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 36 g of a 90% by mass aqueous solution of L-lactic acid, neopentyl glycol Was charged to 2.90 g, 3.85 g of adipic acid, and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) with respect to the raw material aqueous solution (preparation). Since the molar ratio of diglycolic acid units in the raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.89, the converted molar ratio of lactic acid units is 0.0957, The conversion molar ratio of the pentyl glycol unit is 0.0073, and the conversion molar ratio of the adipic acid unit is 0.007.) Like the 6 [Step (A), (B) and (C)] was prepared polycondensation operation was carried out, glycolic acid having a weight average molecular weight 14,400 copolymers.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after the completion of [Step (A)] is 2,500, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. is 2,700. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 90 minutes based on the point in time at which the temperature exceeded 190 ° C. Thus, the increase in the weight average molecular weight per hour in this time range was 4,867.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. In the same manner as in 2 (b-1), a glycolic acid copolymer having a weight average molecular weight of 44,500 and a melting point of 183 ° C. crystallized by melt polycondensation, crystallization and pulverization (hereinafter referred to as “crystal”) Glycolic acid copolymer P-14).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-14, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analysis value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 189,000, and the copolymer composition was 88.63 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, 9.57 mol% of lactic acid units, which are hydroxycarboxylic acid units other than glycolic acid units, 0.90 mol% of neopentylglycol units, and 0.87 mol% of adipic acid units. The average chain length of lactic acid units is 1.05 and coloring degree were 30.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 39, which was almost good. In addition, the oxygen gas permeability of the melt molded sheet was 8.8 (cc / m ² · day · atm), and the sheet had extremely high gas barrier properties. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 4 shows the analysis values and the evaluation results.

[Example 14]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 365 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 36 g of a 90% by mass aqueous solution of L-lactic acid, neopentyl glycol 2.80 g, trimethylolpropane 0.03 g, adipic acid 3.85 g, and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻ as germanium metal atoms per gram of monomer) with respect to the raw material aqueous solution. ^Since the molar ratio of diglycolic acid units in the charged raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.8905, and the converted amount of lactic acid units is 6 mol. The molar ratio is 0.09535, the converted molar ratio of neopentyl glycol units is 0.00711, and the trimethylol [Steps (A), (B) and (C)] are the same as in Example 6 except that the reduced molar ratio of the bread unit is 0.00006 and the reduced molar ratio of the adipic acid unit is 0.00698.) To obtain a glycolic acid copolymer having a weight average molecular weight of 15,900.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after completion of [Step (A)] is 2,800, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. is 3,000. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 85 minutes based on the point in time at which the temperature exceeded 190 ° C. Thus, the increase in the weight average molecular weight per hour in this time range was 4,941.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. 2 (b-1), a glycolic acid copolymer having a weight average molecular weight of 46,800 and a melting point of 180 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment (hereinafter referred to as “crystal”). Glycolic acid copolymer P-15).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-15, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 280,000, and the copolymer composition was 88.62 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, 9.56 mol% of lactic acid units which are hydroxycarboxylic acid units other than glycolic acid units, 0.90 mol% of neopentylglycol units, 0.01 mol% of trimethylolpropane units, 0.88 mol% of adipic acid units The average chain length of the lactic acid units was 1.01, and the degree of coloring was 33.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 42, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 9.2 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 4 shows the analysis values and the evaluation results.

[Example 15]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 365 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 30 g of a 90% by mass aqueous solution of L-lactic acid, neopentyl 6.02 g of glycol, 8.30 g of adipic acid, and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atoms per 1 g of monomer) were charged to the raw material aqueous solution ( Since the molar ratio of diglycolic acid units in the charged raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.89, and the converted molar ratio of lactic acid units is 0.0797. The converted molar ratio of neopentyl glycol units is 0.0153, and the converted molar ratio of adipic acid units is 0.015.) Similarly to Example 6 [Step (A), (B) and (C)] was prepared polycondensation operation was carried out weight-average molecular weight glycolic acid copolymer of 14,400 in.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after [Step (A)] was 2,500, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. was 2,700. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 90 minutes based on the time when the temperature exceeded 190 ° C. Thus, the increase in the weight average molecular weight per hour in this time range was 4,867.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, pulverization treatment The obtained glycolic acid copolymer was used in Examples. The glycolic acid copolymer having a weight average molecular weight of 44,700 and a melting point of 182 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in 2 (b-1) Glycolic acid copolymer P-16).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-16, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 189,000, and the copolymer composition was 88.25 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, 7.93 mol% of lactic acid units, which are hydroxycarboxylic acid units other than glycolic acid units, 1.91 mol% of neopentyl glycol units, and 1.88 mol% of adipic acid units. The average chain length of lactic acid units is 1.05 and coloring degree were 30.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 38, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 12.0 (cc / m 2 · day · atm), and had high gas barrier properties. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 4 shows the analysis values and the evaluation results.

[Comparative Example 5]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 15 g of a 90% by mass aqueous solution of L-lactic acid, neopentyl glycol Was charged to 2.7 g, 3.64 g of adipic acid, and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) with respect to the raw material aqueous solution (preparation). Since the molar ratio of diglycolic acid units in the raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.9428, the converted molar ratio of lactic acid units is 0.0427, The converted molar ratio of the pentyl glycol unit is 0.0074 and the converted molar ratio of the adipic acid unit is 0.0071.)施例 3 similarly to [Step (A), (B) and (C)] was prepared polycondensation operation was carried out weight-average molecular weight glycolic acid copolymer of 16,200 in.

In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after [Step (A)] was completed was 1,900, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. was 2,100. The time required for the weight-average molecular weight of the glycolic acid copolymer to reach 10,000 was 80 minutes based on the point at which the temperature exceeded 190 ° C. Thus, the increase in the weight average molecular weight per hour in this time range was 5,925.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, pulverization treatment The obtained glycolic acid copolymer was used in Examples. 3 (b-1), a glycolic acid copolymer having a weight average molecular weight of 44,500 and a melting point of 208 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in (b-1). Glycolic acid copolymer P-17).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-17, solid phase polymerization was carried out in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 165,000, and the copolymer composition was 93.95 mol% of glycolic acid units and 0.03 of diglycolic acid units. Mol%, 4.21 mol% of lactic acid units which are hydroxycarboxylic acid units other than glycolic acid units, 0.92 mol% of neopentylglycol units, and 0.89 mol% of adipic acid units, and the average chain length of the lactic acid units. Was 1.02 and the degree of coloring was 34.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Molded Sheet The melt-molded sheet had an oxygen gas permeability of 8.3 (cc / m ² · day · atm) and had extremely high gas barrier properties. The strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil. As a result of evaluating the melting heat stability, the coloring degree was 110 and the color was changed to brown.
Table 4 shows the analysis values and the evaluation results.

[Example 16]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 40.83 g of a 90% by mass aqueous solution of L-lactic acid, and After charging 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) to the raw material aqueous solution, nitrogen substitution was performed. Since the molar ratio of diglycolic acid units in the charged raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.89, and the converted molar ratio of lactic acid units is 0.11. is there.

Thereafter, the separable flask was immersed in an oil bath at a temperature of 120 ° C., and dehydration was performed by maintaining the stirring rotation speed at 200 rpm for 1 hour under a nitrogen stream. Thereafter, with the reaction temperature kept at 120 ° C., 1 hour at 8.0 × 10 ⁴ Pa, 1 hour at 6.0 × 10 ⁴ Pa, 1 hour at 5.0 × 10 ⁴ Pa, 4.0 × 10 ⁴ Pa. 1 hour at ⁴ Pa, 1 hour at 2.5 × 10 ⁴ Pa, 1 hour at 1.0 × 10 ⁴ Pa, 1 hour at 5.0 × 10 ³ Pa, ³ hours at 2.0 × 10 ³ Pa, The polycondensation reaction was carried out [(Step (A)]. In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution was reduced from the time when the degree of reduced pressure was set to 4.0 × 10 ³ Pa. Showed a substantially constant value of 116 ° C. After the completion of this step, the molecular weight of the glycolic acid copolymer was measured by sampling a small amount, and as a result, the weight average molecular weight was 1,500.

Thereafter, the temperature was gradually raised to a reaction temperature of 190 ° C. over 40 minutes while maintaining the stirring rotation speed and the reduced pressure state [Step (B)]. As a result of sampling a small amount of the molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C., the weight average molecular weight was 1,700.
Subsequently, the reaction temperature was raised to 200 ° C. in 10 minutes, the stirring speed was changed to 600 rpm, and the total reaction time after exceeding 190 ° C. at a reduced pressure of 4.0 × 10 ² Pa was obtained. The reaction was continued for 2.5 hours to obtain a glycolic acid copolymer having a weight-average molecular weight of 13,000 [(Step (C)]), where the temperature of the reaction solution exceeded 190 ° C. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 110 minutes, and the increase in the weight average molecular weight per hour in this time range was 4,527.
The obtained glycolic acid copolymer in a molten state was cooled and solidified, taken out, and subsequently, the obtained glycolic acid copolymer was polymerized by the following operation.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. 2 (b-1), a glycolic acid copolymer having a weight average molecular weight of 42,500 and a melting point of 184 ° C. crystallized by melt polycondensation, crystallization and pulverization in the same manner as in (b-1). Glycolic acid copolymer P-18).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-18, solid phase polymerization was carried out in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the glycolic acid copolymer obtained after the solid phase polymerization was 178,000, and the composition was 88.98 mol% of glycolic acid units and diglycolic acid. The unit contained 0.02 mol% of a lactic acid unit as a hydroxycarboxylic acid unit other than the glycolic acid unit at 11.00 mol%, the average chain length of the lactic acid unit was 1.02, and the degree of coloring was 28.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 39, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 8.1 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 5 shows the analysis values and the evaluation results.

[Example 17]
(A) Production of low molecular weight glycolic acid copolymer
After performing dehydration while maintaining the reaction operation conditions in [Step (A)] for 1.5 hours under a nitrogen stream, the oil bath temperature was kept at 150 ° C., and 5.0 × 10 ⁴ Pa was applied for 1 hour. The procedure was the same as in Example 2 except that the time was changed to 2.5 × 10 ⁴ Pa for 0.5 hour, 1.0 × 10 ⁴ Pa for 50 minutes, and 5.0 × 10 ³ Pa for 25 minutes. A), (B) and (C)] to produce a glycolic acid copolymer having a weight average molecular weight of 12,800.
In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after completion of [Step (A)] is 900, the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. is 1,100, and the reaction temperature is 190. The time required until the weight average molecular weight of the glycolic acid copolymer reached 10,000 on the basis of the point at which the temperature exceeded ℃ was 110 minutes. From this, the increase in the weight average molecular weight per hour in this time range was 4,855.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid-phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer in a molten state Was subjected to melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in Example 2 (b-1) to crystallize a glycolic acid copolymer having a weight average molecular weight of 42,800 and a melting point of 184 ° C. , Crystallized glycolic acid copolymer P-19).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-19, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 148,000, and the copolymer composition was 88.93 mol% of glycolic acid units and 0.06 of diglycolic acid units. The lactic acid unit contained 11.01 mol% as a hydroxycarboxylic acid unit other than the glycolic acid unit, and the average chain length of the lactic acid unit was 1.05 and the degree of coloring was 28.
(D) Evaluation of glycolic acid copolymer and melt-molded sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 44, which was almost good. In addition, the oxygen gas permeability of the melt molded sheet was 8.1 (cc / m ² · day · atm), and the sheet had extremely high gas barrier properties. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 5 shows the analysis values and the evaluation results.

[Example 18]
(A) Production of low molecular weight glycolic acid copolymer
[Step (A)] After completion of [Step (A)], the temperature was gradually raised to a reaction temperature of 190 ° C. over a period of 80 minutes while maintaining the stirring rotation speed and the reduced pressure. (A) and (C)] to produce a glycolic acid copolymer having a weight average molecular weight of 13,800.
In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after completion of [Step (A)] is 900, the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. is 2,100, and the reaction temperature is 190. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 100 minutes based on the time when the temperature exceeded ℃. From this, the increase in the weight average molecular weight per hour in this time range was 4,740.

(B) Melt polycondensation, crystallization treatment, pulverization treatment, and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment, and pulverization treatment The obtained glycolic acid copolymer was used in Examples. The glycolic acid copolymer having a weight average molecular weight of 43,500 and a melting point of 185 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in 2 (b-1) Glycolic acid copolymer P-20).
(B-2) Solid-phase polymerization of crystallized glycolic acid copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-20, solid-phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 132,000, and the copolymer composition was 88.91 mol% of glycolic acid units and 0.08 of diglycolic acid units. It contained 11.01 mol% of a lactic acid unit as a hydroxycarboxylic acid unit other than the glycolic acid unit, and the average chain length of the lactic acid unit was 1.02 and the degree of coloring was 28.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 48, which was almost good. Moreover, the oxygen gas permeability of the melt-molded sheet was 8.0 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 5 shows the analysis values and the evaluation results.

[Example 19]
(A) Production of low molecular weight glycolic acid copolymer
[Step (B)] After the completion, the reaction temperature was continuously raised to 200 ° C. in 10 minutes, the stirring rotation was maintained at 200 rpm, and the total reaction time after exceeding 190 ° C. was 6 hours. The polycondensation operation of [Steps (A), (B) and (C)] was carried out in the same manner as in Example 2 except that the above was continued to produce a glycolic acid copolymer having a weight average molecular weight of 12,000.
In [Step (A)], the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed an almost constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. At this time, the weight average molecular weight of the glycolic acid copolymer after the completion of [Step (A)] was 1,900, and the weight average molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. was 2,100. The time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 290 minutes based on the time when the reaction temperature exceeded 190 ° C. From this, the increase in the weight average molecular weight per hour in this time range was 1,634.

(B) Melt polycondensation, crystallization treatment, pulverization treatment and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment and pulverization treatment The obtained glycolic acid copolymer was prepared in Example 2. A glycolic acid copolymer having a weight average molecular weight of 42,800 and a melting point of 184 ° C. crystallized by performing melt polycondensation, crystallization treatment and pulverization treatment in the same manner as (b-1) Acid copolymer P-21).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-21, solid phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 152,000, and the copolymer composition was 88.92 mol% of glycolic acid units and 0.07 of diglycolic acid units. It contained 11.01 mol% of a lactic acid unit as a hydroxycarboxylic acid unit other than the glycolic acid unit, and the average chain length of the lactic acid unit was 1.02 and the degree of coloring was 28.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 46, which was almost good. Further, the oxygen gas permeability of the melt-molded sheet was 8.0 (cc / m ² · day · atm), and had an extremely high gas barrier property. Furthermore, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 5 shows the analysis values and the evaluation results.

[Example 20]
Example 2 (b-1) except that the glycolic acid copolymer obtained by the method described in “(a) Production of low molecular weight glycolic acid copolymer” in Example 16 was used, except that the reaction time was changed to 1.5 hours. ), A glycidic acid copolymer having a weight average molecular weight of 20,000 and a melting point of 185 ° C. (hereinafter, referred to as crystallized glycol) is subjected to crystallization treatment and pulverization treatment. Acid copolymer P-22).
(B-2) Solid-phase polymerization of crystallized glycolic acid copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-22, solid-phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 93,000, and the copolymer composition was 88.98 mol% of glycolic acid units and 0.02 of diglycolic acid units. It contained 11.00 mol% of lactic acid units as mol carboxylic acid units other than glycolic acid units, the average chain length of the lactic acid units was 1.02, and the degree of coloring was 27.

(D) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet As a result of evaluating the melt heat stability of the obtained glycolic acid copolymer, the coloring degree was 38, which was almost good. The oxygen gas permeability of the melt molded sheet was 8.1 (cc / m ² · day · atm), and the sheet had extremely high gas barrier properties. The strength of the melt-formed sheet was 4, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil.
Table 5 shows the analysis values and the evaluation results.

[Comparative Example 6]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 349 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 39.3 g of a 90% by mass aqueous solution of L-lactic acid, 0.60 g of pentyl glycol and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) were charged to the aqueous solution of the raw material (di-methyl in the raw material charged). Since the molar ratio of glycolic acid units is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.8896, the converted molar ratio of lactic acid units is 0.1088, and the converted molar ratio of neopentyl glycol units is The reduced molar ratio was 0.0016.) Then, nitrogen substitution was performed. Thereafter, the separable flask was immersed in an oil bath at a temperature of 150 ° C., and the stirring speed was set to 100 revolutions per minute, and the mixture was held for 1.5 hours under a nitrogen stream to perform dehydration. Next, the polycondensation reaction was performed at 5.0 × 10 ⁴ Pa for 1 hour, at 2.5 × 10 ⁴ Pa for 0.5 hour, and at 1.0 × 10 ⁴ Pa for 20 minutes while keeping the oil bath temperature at 150 ° C. Carried out. In the above step, the temperature of the reaction solution gradually increased, and the temperature of the reaction solution was 146 ° C. from the time when the degree of decompression was set to 1.0 × 10 ⁴ Pa, which was a substantially constant value. As a result of sampling and measuring a small amount of the molecular weight of the glycolic acid copolymer after the completion of the step, the weight average molecular weight was 400.

Thereafter, the temperature was gradually raised to a reaction temperature of 190 ° C. over 120 minutes while maintaining the stirring rotation speed and the reduced pressure. The molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C. was measured by sampling a small amount, and as a result, the weight average molecular weight was 700. Subsequently, the reaction temperature was raised to 200 ° C. in 10 minutes, the stirring speed was changed to 600 rpm, and the total reaction time after exceeding 190 ° C. at a reduced pressure of 4.0 × 10 ² Pa was 3 times. The reaction was continued for an hour to obtain a glycolic acid copolymer having a weight average molecular weight of 14,600. At this time, the time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 120 minutes based on the point in time when the temperature of the reaction solution exceeded 190 ° C. The increase in the weight average molecular weight per hour was 4,650.
The obtained glycolic acid copolymer in a molten state was cooled and solidified, taken out, and subsequently, the obtained glycolic acid copolymer was polymerized by the following operation.

(B) Melt polycondensation, crystallization treatment, pulverization treatment and solid-phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment and pulverization treatment The obtained glycolic acid copolymer was prepared in Example 2. A glycolic acid copolymer having a weight average molecular weight of 42,000 and a melting point of 183 ° C crystallized by melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in (b-1) (hereinafter referred to as crystallized glycol) (Abbreviated as acid copolymer P-23).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-23, solid phase polymerization was carried out in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 186,000, and the copolymer composition was 88.59 mol% of glycolic acid units and 0.20 of diglycolic acid units. Mol%, 11.00 mol% of a lactic acid unit, which is a hydroxycarboxylic acid unit other than the glycolic acid unit, and 0.21 mol% of a neopentylglycol unit. there were.

(D) Evaluation of glycolic acid copolymer and melt-formed sheet The oxygen-gas permeability of the melt-formed sheet was 8.7 (cc / m ² · day · atm), and it had extremely high gas barrier properties. . In addition, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil. Was evaluated for melt heat stability, and as a result, the coloring degree was 224, and the color changed to brown.
Table 6 shows the analysis values and the evaluation results.

[Comparative Example 7]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 349 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 39.3 g of a 90% by mass aqueous solution of L-lactic acid, After charging 0.60 g of pentyl glycol and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) with respect to the raw material aqueous solution, nitrogen substitution was performed. Was. Since the molar ratio of diglycolic acid units in the charged raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.8896, the converted molar ratio of lactic acid units is 0.1088, The converted molar ratio of neopentyl glycol units is 0.0016.

Thereafter, the separable flask was immersed in an oil bath at a temperature of 150 ° C., and the stirring speed was set to 100 revolutions per minute, and the mixture was held under a nitrogen stream for 1.5 hours to perform dehydration. Next, the polycondensation reaction was performed at 5.0 × 10 ⁴ Pa for 1 hour, at 2.5 × 10 ⁴ Pa for 0.5 hour, and at 1.0 × 10 ⁴ Pa for 20 minutes while keeping the oil bath temperature at 150 ° C. Carried out.
In the above step, the temperature of the reaction solution gradually increased, and the temperature of the reaction solution showed a substantially constant value of 146 ° C. from the time when the degree of reduced pressure was set to 1.0 × 10 ⁴ Pa. As a result of sampling and measuring a small amount of the molecular weight of the glycolic acid copolymer after the completion of the step, the weight average molecular weight was 400.

Thereafter, the temperature was gradually raised to a reaction temperature of 190 ° C. over 25 minutes while maintaining the stirring rotation speed and the reduced pressure state. As a result of sampling a small amount of the molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C., the weight average molecular weight was 500. Subsequently, the reaction temperature was raised to 200 ° C. in 10 minutes, the stirring speed was kept at 100 rpm, and the total reaction time after exceeding 190 ° C. at a reduced pressure of 6.0 × 10 ² Pa was calculated. The reaction was continued for 20 hours to obtain a glycolic acid copolymer having a weight average molecular weight of 14,500. At this time, the time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 810 minutes based on the point in time when the temperature of the reaction solution exceeded 190 ° C. The increase in the weight average molecular weight per hour was 704.
The obtained glycolic acid copolymer in a molten state was cooled and solidified, taken out, and subsequently, the obtained glycolic acid copolymer was polymerized by the following operation.

(B) Melt polycondensation, crystallization treatment, pulverization treatment and solid-phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment and pulverization treatment The obtained glycolic acid copolymer was prepared in Example 2. A glycolic acid copolymer having a weight average molecular weight of 44,000 and a melting point of 182 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in (b-1) (hereinafter referred to as crystallized glycol) Acid copolymer P-24).
(B-2) Solid Phase Polymerization of Crystallized Glycolic Acid Copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-24, solid phase polymerization was carried out in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analysis value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 179,000, and the copolymer composition was 88.58 mol% of glycolic acid units and 0.21 of diglycolic acid units. Mol%, 11.00 mol% of lactic acid units, which are hydroxycarboxylic acid units other than glycolic acid units, and 0.21 mol% of neopentyl glycol units. The average chain length of lactic acid units was 1.02, and the degree of coloring was 39. there were.

(D) Evaluation of Glycolic Acid Copolymer and Melt-Molded Sheet The melt-molded sheet had an oxygen gas permeability of 8.8 (cc / m ² · day · atm) and had extremely high gas barrier properties. In addition, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil. Was evaluated for melt heat stability, and as a result, the coloring degree was 242, and it turned brown.
Table 6 shows the analysis values and the evaluation results.

[Comparative Example 8]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 349 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 39.3 g of a 90% by mass aqueous solution of L-lactic acid, After charging 0.60 g of pentyl glycol and 0.05% by mass of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) with respect to the raw material aqueous solution, nitrogen substitution was performed. Was. Since the molar ratio of diglycolic acid units in the charged raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.8896, the converted molar ratio of lactic acid units is 0.1088, The converted molar ratio of neopentyl glycol units is 0.0016.

Thereafter, the separable flask was immersed in an oil bath at a temperature of 150 ° C., and dehydration was performed by maintaining the stirring rotation speed at 100 rpm for 1.5 hours under a nitrogen stream. Then, while the oil bath temperature of 0.99 ° C., 1 hour at 5.0 × ¹⁰ 4 Pa, 0.5 hours at 2.5 × ¹⁰ 4 Pa, 50 minutes 1.0 × ¹⁰ 4 Pa, 5.0 A polycondensation reaction was performed at × 10 ³ Pa for 20 minutes.
In the above step, the temperature of the reaction solution gradually increased, and the temperature of the reaction solution was 146 ° C. from the time when the degree of decompression was set to 1.0 × 10 ⁴ Pa, which was a substantially constant value. After the completion of the step, a small amount of the molecular weight of the glycolic acid copolymer was sampled and measured. As a result, the weight average molecular weight was 900.

Thereafter, the temperature was gradually raised to a reaction temperature of 190 ° C. over 120 minutes while maintaining the stirring rotation speed and the reduced pressure. As a result of measuring a small amount of the molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C., the weight average molecular weight was 1,500. Subsequently, the reaction temperature was raised to 200 ° C. in 10 minutes, the stirring speed was kept at 100 rpm, and the total reaction time after exceeding 190 ° C. at a reduced pressure of 6.0 × 10 ² Pa was calculated. The reaction was continued for 20 hours to obtain a glycolic acid copolymer having a weight average molecular weight of 15,600. At this time, the time required for the weight average molecular weight of the glycolic acid copolymer to reach 10,000 was 720 minutes based on the point in time when the temperature of the reaction solution exceeded 190 ° C., and this time range was 1 minute. The increase in the weight average molecular weight per hour was 708.
The obtained glycolic acid copolymer in a molten state was cooled and solidified, taken out, and subsequently, the obtained glycolic acid copolymer was polymerized by the following operation.

(B) Melt polycondensation, crystallization treatment, pulverization treatment and solid phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment and pulverization treatment The obtained glycolic acid copolymer was prepared in Example 2. A glycolic acid copolymer having a weight average molecular weight of 44,800 and a melting point of 182 ° C. crystallized by performing melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in (b-1) (hereinafter, crystallized glycol) Acid Copolymer P-25).
(B-2) Solid-phase polymerization of crystallized glycolic acid copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-25, solid-phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analytical value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 184,000, and its copolymer composition was 88.62 mol% of glycolic acid units and 0.18 of diglycolic acid units. Mol%, 11.00 mol% of lactic acid units, which are hydroxycarboxylic acid units other than glycolic acid units, and 0.20 mol% of neopentyl glycol units. The average chain length of lactic acid units was 1.02, and the degree of coloring was 37. there were.

(D) Evaluation of Glycolic Acid Copolymer and Melt-Molded Sheet The melt-molded sheet had an oxygen gas permeability of 8.8 (cc / m ² · day · atm) and had extremely high gas barrier properties. In addition, the strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil. As a result of evaluating the melting heat stability, the coloring degree was 196, and the color changed to brown.
Table 6 shows the analysis values and the evaluation results.

[Comparative Example 9]
(A) Production of low molecular weight glycolic acid copolymer
In the same apparatus as in Example 1, 360 g of a 70% by mass aqueous solution of glycolic acid having a diglycolic acid content of 0.005 mol% or less based on glycolic acid, 40.83 g of a 90% by mass aqueous solution of L-lactic acid, and After charging 0.05 mass% of tetraisopropoxygermanium (2.2 × 10 ⁻⁶ mol as germanium metal atom per 1 g of monomer) to the raw material aqueous solution, nitrogen substitution was performed. Since the molar ratio of diglycolic acid units in the charged raw material is 0.00005 or less, the converted molar ratio is 0, the converted molar ratio of glycolic acid units is 0.89, and the converted molar ratio of lactic acid units is 0.11. is there.

Thereafter, the separable flask was immersed in an oil bath at a temperature of 180 ° C., dehydration was performed for 3 hours under a nitrogen stream at a stirring rotation speed of 200 rpm, and the reaction temperature was kept at 180 ° C. 1 hour at 5.0 × ¹⁰ 4 Pa, 0.5 hours at 2.5 × ¹⁰ 4 Pa, 30 minutes 1.0 × ¹⁰ 4 Pa, 30 minutes 5.0 × ¹⁰ 3 Pa, 2.0 × The polycondensation reaction was performed at 10 ³ Pa for 20 minutes.
In this step, the weight average molecular weight of the glycolic acid copolymer at the time when the reaction temperature exceeded 160 ° C. after immersion in a 180 ° C. oil bath under a nitrogen stream was 300. After completion of this step, a small amount of the molecular weight of the glycolic acid copolymer was sampled and measured. As a result, the weight average molecular weight was 2,200.

Thereafter, the temperature was gradually raised to a reaction temperature of 190 ° C. over 15 minutes while maintaining the stirring rotation speed and the reduced pressure state. As a result of sampling a small amount of the molecular weight of the glycolic acid copolymer at a reaction temperature of 190 ° C., the weight average molecular weight was 2,300.
Subsequently, the reaction temperature was raised to 200 ° C. in 10 minutes, the stirring speed was changed to 600 rpm, and the total reaction time after exceeding 190 ° C. at a reduced pressure of 4.0 × 10 ² Pa was obtained. The reaction was continued for 2.5 hours to obtain a glycolic acid copolymer having a weight average molecular weight of 14,100.
The obtained glycolic acid copolymer in a molten state was cooled and solidified, then taken out, and subsequently, the obtained glycolic acid copolymer was polymerized by the following operation.

(B) Melt polycondensation, crystallization treatment, pulverization treatment and solid-phase polymerization of glycolic acid copolymer (b-1) Melt polycondensation, crystallization treatment and pulverization treatment The obtained glycolic acid copolymer was prepared in Example 2. A glycolic acid copolymer having a weight average molecular weight of 43,600 and a melting point of 183 ° C. crystallized by melt polycondensation, crystallization treatment and pulverization treatment in the same manner as in (b-1) (hereinafter referred to as crystallized glycol) Acid copolymer P-26).
(B-2) Solid-phase polymerization of crystallized glycolic acid copolymer Subsequently, using the obtained crystallized glycolic acid copolymer P-26, solid-phase polymerization was performed in the same manner as in Example 2 (b-2). Polymerization was performed.

(C) Analysis value of glycolic acid copolymer The weight average molecular weight of the obtained glycolic acid copolymer was 109,000, and the copolymer composition was 88.84 mol% of glycolic acid units and 0.14 of diglycolic acid units. It contained 11.02 mol% of lactic acid units as mol carboxylic acid units other than glycolic acid units. The average chain length of the lactic acid units was 1.02 and the degree of coloring was 38.
(D) Evaluation of Glycolic Acid Copolymer and Melt-Molded Sheet The melt-molded sheet had an oxygen gas permeability of 8.3 (cc / m ² · day · atm) and had extremely high gas barrier properties. In addition, the strength of the melt-formed sheet was 4, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil. As a result of evaluating the melting heat stability, the coloring degree was 158, and the color changed to brown.
Table 6 shows the analysis values and the evaluation results.

[Reference Example 1]
A glycolic acid-lactic acid copolymer was synthesized by a ring-opening polymerization method according to the following procedure.
(A) Preparation of Raw Materials for Polymerization (a-1) Preparation of Purified Glycolide 250 g of glycolide was dissolved in 500 g of dehydrated ethyl acetate at 75 ° C., and left to precipitate at room temperature for 10 hours. The precipitate collected by filtration was washed with about 500 g of dehydrated ethyl acetate at room temperature. This washing operation was repeated again. The washed material was put in an eggplant-shaped flask, immersed in an oil bath set at 60 ° C., and vacuum-dried for 24 hours. Using this dried product, 95 g of purified glycolide (boiling point: 133 to 134 ° C./degree of reduced pressure: 9 × 10 ² to 8 × 10 ² Pa) was obtained by simple distillation, stored under dry nitrogen, and used for the next polymerization operation. Provided.

(A-2) Preparation of purified lactide 250 g of L-lactide was dissolved in 500 g of dehydrated toluene at 80 ° C., and left at room temperature for 10 hours to precipitate. The precipitate collected by filtration was washed with about 500 g of dehydrated toluene at room temperature. After repeating this washing operation again, the washed matter is put in an eggplant-shaped flask, immersed in an oil bath set at 60 ° C., vacuum-dried for 24 hours to obtain 120 g of purified L-lactide, and then stored under dry nitrogen. Then, it was subjected to the next polymerization operation.

(B-1) Synthesis of glycolic acid copolymer [a] Under dry nitrogen, 84 g of glycolide and 19 g of lactide obtained by purification of the above monomer, and 0.03 g of tin 2-ethylhexanoate as a catalyst were used. 0.01 g of dehydrated lauryl alcohol was charged into a pressure-resistant tube whose inside was sufficiently dried and coated with Teflon (registered trademark). After stoppering, it was immersed in a shaking oil bath set at 130 ° C. and shaken for 20 hours to carry out polymerization. After completion of the polymerization, the mixture was cooled to room temperature, and the bulk polymer taken out of the pressure-resistant tube was pulverized into fine particles of about 1 mm or less. This pulverized product was subjected to Soxhlet extraction using dehydrated ethyl acetate for 10 hours, and then vacuum dried in a vacuum dryer for 24 hours to obtain 95 g of a glycolic acid copolymer.

(B-2) Synthesis of glycolic acid copolymer [b] Under dry nitrogen, 84 g of glycolide obtained by purification of the above monomer, 39 g of lactide, and 0.037 g of tin 2-ethylhexanoate as a catalyst were dehydrated. A sufficiently dried inside of 0.012 g of lauryl alcohol was charged into a pressure-resistant tube coated with Teflon (registered trademark). After stoppering, it was immersed in a shaking oil bath set at 130 ° C. and shaken for 20 hours to carry out polymerization. After completion of the polymerization, the mixture was cooled to room temperature, and the bulk polymer taken out of the pressure-resistant tube was pulverized into fine particles of about 1 mm or less. This pulverized product was subjected to Soxhlet extraction for 10 hours using dehydrated ethyl acetate, and then vacuum-dried in a vacuum dryer for 24 hours to obtain 116 g of a glycolic acid copolymer.

[Comparative Example 10]
(A) Analytical value of glycolic acid copolymer The weight average molecular weight of the glycolic acid copolymer [a] obtained by the ring-opening polymerization method obtained in (b-1) of Reference Example 1 was 175,000. The copolymer composition contained 94.00 mol% of a glycolic acid unit and 6.00 mol% of a lactic acid unit which is a hydroxycarboxylic acid unit other than the glycolic acid unit, and no diglycolic acid unit was confirmed. The average chain length of the lactic acid units was 2.08, and the degree of coloring was 30.

(B) Evaluation of glycolic acid copolymer and melt-formed sheet The oxygen-gas permeability of the melt-formed sheet of glycolic acid copolymer [a] obtained in Reference Example (b-1) was 8.8 (cc / m). ² * day * atm), and had extremely high gas barrier properties. The strength of the melt-formed sheet was 5 or more, and it had the mechanical strength necessary for molded articles such as containers and films, and the melt-formed sheet had disintegration properties in soil. As a result of evaluating the melting heat stability of [a], the coloring degree was 92, and the color changed to yellow.
Table 6 shows the analysis values and the evaluation results.

[Comparative Example 11]
(A) Analysis value of glycolic acid copolymer The weight average molecular weight of the glycolic acid copolymer [b] obtained by the ring-opening polymerization method obtained in (b-2) of Reference Example 1 was 183,000. The copolymer composition contained 83.00 mol% of glycolic acid units and 17.00 mol% of lactic acid units, which are hydroxycarboxylic acid units other than glycolic acid units, and no diglycolic acid units were confirmed. The average chain length of the lactic acid units was 2.36 and the degree of coloring was 29.

(B) Evaluation of Glycolic Acid Copolymer and Melt-Formed Sheet The melt-formed sheet of glycolic acid copolymer [b] obtained in Reference Example (b-2) has a strength of 5 or more, and is a molded product such as a container or a film. In addition to having the mechanical strength necessary for the above, the melt-formed sheet had disintegration properties in soil, but the oxygen gas permeability was 28 (cc / m ² · day · atm) and the gas barrier property was low. Met. Further, as a result of evaluating the melting heat stability, the coloring degree was 58, and the color changed to yellow.
Table 6 shows the analysis values and the evaluation results.

[Reference Example 2]
The same as the embodiment of the present invention except that the weight average molecular weight of the glycolic acid copolymer obtained in Example 18 (b-2) was changed to hexafluoroisopropanol in which sodium trifluoroacetate was not dissolved, as an eluent. As a result, the weight average molecular weight of the glycolic acid copolymer was 583,000.

The present invention has high thermal stability and excellent quality, and the molded article after processing is suitably used as a resin having high barrier properties and sufficient mechanical strength, and the resin is efficiently treated by a simple method. It is suitable as a method for producing well industrially.

Claims (22)

A glycolic acid copolymer having a weight average molecular weight of 50,000 or more and a glycolic acid unit content of 80 mol% or more and less than 95 mol%, wherein glycolic acid satisfies the following [1] and [2]: Copolymer.
[1] A hydroxycarboxylic acid unit other than the glycolic acid unit is contained in an amount of 5.0 mol% or more and 20.0 mol% or less, and the average chain length of the hydroxycarboxylic acid unit other than the glycolic acid unit is 1.00 or more and 1.50 or less. [2] Diglycolic acid unit content of 0 or 0.10 mol% or less 2. The glycolic acid copolymer according to claim 1, wherein the weight average molecular weight of the glycolic acid copolymer is 80,000 or more. 3. The glycolic acid copolymer according to claim 1, wherein the content of diglycolic acid unit is more than 0 and not more than 0.09 mol%. 4. The glycolic acid copolymer according to any one of claims 1 to 3, wherein the weight average molecular weight of the glycolic acid copolymer is 100,000 or more. The glycolic acid copolymer according to any one of claims 1 to 4, wherein the average chain length of the hydroxycarboxylic acid units other than the glycolic acid unit is from 1.00 to 1.20. 6. The glycolic acid copolymer according to claim 1, wherein the hydroxycarboxylic acid unit other than the glycolic acid unit is a monohydroxymonocarboxylic acid. 7. グ リ コ ー ル The glycolic acid copolymer according to any one of claims 1 to 6, comprising at least a polyol unit. 8. The glycolic acid according to claim 7, wherein the polyol unit is at least one selected from a diol unit having 3 or more carbon atoms and a compound unit having 4 or more carbon atoms having 3 or more hydroxyl groups in one molecule. Copolymer. 10. The glycolic acid copolymer according to claim 8, wherein the polyol unit is selected from compound units having 5 or more carbon atoms. 10. The glycolic acid copolymer according to claim 9, wherein the polyol unit is a neopentyl glycol unit. The glycolic acid copolymer according to any one of claims 7 to 10, wherein the total content of the polyol unit and the polycarboxylic acid unit in the glycolic acid copolymer is less than 2.0 mol%. United. The sum of the contents of the polyol unit and the polycarboxylic acid unit is more than 0.02 mol% and less than 2.0 mol%, and the content of the polyol unit is 0.02 mol% or more and less than 2.0 mol%. The glycolic acid copolymer according to any one of claims 7 to 11, characterized in that: 2. The glycolic acid copolymer according to claim 1, wherein the hydroxycarboxylic acid unit other than the glycolic acid unit is a lactic acid and / or 6-hydroxyhexanoic acid unit. The method according to any one of claims 1 to 13, which is obtained by polycondensation using glycolic acid and / or a derivative thereof and a compound copolymerizable with glycolic acid and / or a derivative thereof as a starting material. The glycolic acid copolymer according to the above. Using a raw material comprising glycolic acid and / or a derivative thereof and a compound copolymerizable with the glycolic acid and / or a derivative thereof, including a hydroxycarboxylic acid other than glycolic acid and / or a derivative thereof, by polycondensation A method for producing a glycolic acid copolymer, which comprises the following [Steps (A), (B) and (C)].
(A) A step of producing a glycolic acid copolymer having a weight-average molecular weight of 700 to 5,000 by performing a polycondensation reaction at a reaction temperature of 20 ° C to 160 ° C [Step (A)] ].
(B) Following [Step (A)], a step of raising the reaction temperature to 190 ° C. within 100 minutes [Step (B)].
(C) When producing a glycolic acid copolymer having a weight average molecular weight of 10,000 or more by performing a polycondensation reaction at a reaction temperature in a range of 190 ° C. or more and 300 ° C. or less following [Step (B)]. Subjecting the glycolic acid copolymer to a polycondensation reaction under the condition that the weight-average molecular weight increases until the weight-average molecular weight reaches 10,000 or more per hour [step (C)] ]. The glycolic acid copolymer obtained by the method according to claim 15 is further subjected to polycondensation at a reaction temperature in a range from 190 ° C to 300 ° C, according to any one of claims 1 to 14, wherein A method for producing a glycolic acid copolymer. Glycolic acid is obtained by polycondensation using glycolic acid and / or a derivative thereof, a hydroxycarboxylic acid other than glycolic acid and / or a derivative thereof, and, if necessary, a raw material containing a polyol, a polycarboxylic acid and / or a derivative thereof. 16. The method for producing a glycolic acid copolymer according to claim 15, wherein a raw material satisfying the following formulas (1), (2) and (3) is used when producing the copolymer.

(Where [X-1] is a reduced molar ratio of glycolic acid and / or its derivative, [X-2] is a reduced molar ratio of hydroxycarboxylic acid other than glycolic acid and / or its derivative, [X- 3] and [X-4] represent the reduced molar ratio of the polyol, polycarboxylic acid and / or derivative thereof used as needed, and [X-3] and [X-4] are independently 0. May be.) 18. The method for producing a glycolic acid copolymer according to claim 17, wherein a raw material containing at least a polyol unit and satisfying the following formulas (4) and (5) is used.

(However, [X-1], [X-2], [X-3] and [X-4] are the same as above. [X-4] may be 0.) 18. The method for producing a glycolic acid copolymer containing a polyol unit and a polycarboxylic acid unit, wherein the following formulas (6) and (7) are satisfied.

(However, [X-1], [X-2], [X-3] and [X-4] are the same as above. [X-4] may be 0.) 18. The method for producing a glycolic acid copolymer according to claim 17, wherein a raw material containing at least a polyol unit and satisfying the following formula (8) is used.

(However, [X-1], [X-2], [X-3] and [X-4] are the same as above. [X-4] may be 0.) The glycolic acid according to any one of claims 1 to 14, wherein the glycolic acid copolymer produced by the method according to claim 15 is crystallized and solid-phase polymerized at a temperature that maintains a solid state. A method for producing a copolymer. A molded article obtained from the glycolic acid copolymer according to any one of claims 1 to 14.