JPH09176300A - Manufacture of high molecular weight aliphatic polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a high molecular weight aliphatic polyester by a specific condition whereby the generation of byproducts and low molecular weight compounds due to depolymerization can be kept lowered under a reduced pressure of practical use and enables a commercially efficient production of the high molecular weight aliphatic polyester. SOLUTION: In manufacturing an aliphatic polyester with a number - average molecular weight of 10,000-100,000 by a process involving transesterification, the transesterification is conducted under keeping the total amount of the content in a reaction system not more than 70% of the inside volume of a reaction vessel. Preferably this transesterification is conducted under a reduced reaction pressure in the range of 0.5-5.0mmHg. This high molecular weight aliphatic polyester is obtained from e.g. a 2-6C aliphatic dicarboxylic acid component and a 2-4C aliphatic glycol component or from e.g. cyclic acid anhydrides with succinic acid as a major component and cyclic ethers with ethylene oxide as a major component through a process involving ring-opening copolymerization.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a high molecular weight aliphatic polyester.

[0002]

2. Description of the Related Art Aliphatic polyesters are generally recognized to be biodegradable, and it is expected that they will be used alone or in combination with various additives for fibers, molded products, sheets and films. As a method for producing such a polyester, a dicarboxylic acid and a glycol are directly esterified, or an alkyl ester of a dicarboxylic acid and a glycol are transesterified to obtain a glycol ester and / or a low polymer thereof, and then Generally, a method of heating and stirring this under high vacuum for a long time to cause polycondensation is carried out. For example, JP-A-5-310898 discloses that a glycol component and a dicarboxylic acid component are used in the presence of a catalyst.
It has been proposed to carry out a deglycolization reaction under the conditions of 80 to 230 ° C. and 0.05 to 0.1 mmHg to produce a high molecular weight aliphatic polyester. Further, JP-A-6-32
No. 2081 proposes to produce a high molecular weight aliphatic polyester from a glycol component and a dicarboxylic acid component in the presence of a catalyst under reaction conditions including 240 ° C. and 1 mmHg or less.

However, in these methods of polycondensation under high vacuum for a long time, not only water produced in the esterification reaction and glycol produced in the transesterification reaction but also the high vacuum for a long time, so that by-products and A large amount of low molecular weight compounds are generated by depolymerization. Since these volatile components are rarely used, they have been a big economic problem. Further, there are problems such that the reaction time is remarkably lengthened and the molecular weight does not reach a predetermined level due to a reduction in the degree of pressure reduction due to these volatile components and a reduction in the performance of the vacuum pump.

Further, such a pump for maintaining a high vacuum is a special pump which is expensive, and it requires a considerable amount of labor for maintenance and maintenance for maintaining a high vacuum, so it is not industrial. I can't really say.

For the industrial production of high molecular weight aliphatic polyesters, the usual saturated polyesters, the so-called P
It is indispensable to develop a manufacturing method that can be manufactured by a general-purpose pump with a reduced pressure of 0.5 mmHg, preferably about 1 mmHg, which is used for manufacturing ET and the like.

[0006]

The inventors of the present invention have conducted extensive studies for the production of high-molecular-weight aliphatic polyesters, and found that the conventional method keeps a high vacuum for a long time, so that the volatilization that occurs during the reaction occurs. There is a problem that the reaction time is remarkably lengthened or the molecular weight does not reach a prescribed level, which causes a decrease in the degree of vacuum in the reaction system and a decrease in the performance of the vacuum pump. found. Furthermore, it was found that these volatile matters are not economically utilized, which is a big economic problem.

In particular, the deglycolization step, which is a transesterification reaction, and the reaction conditions after the number average molecular weight of 5,000 or more has hitherto been a pressure reduction degree of 1.0 mmHg or less, preferably 0.5 mmHg or less in the reaction system. Vacuum has been an indispensable condition (for example, JP-A-5-310898 and JP-A-6-322081).

When a high vacuum whose degree of pressure reduction is higher than 0.5 mmHg is maintained as described above, the volatile matter becomes remarkably large due to the formation of oligomers due to the decomposition reaction of polyester, and a large amount of volatile matter is present between the reaction vessel and the trap during the reaction. Volatiles are clogged,
The vacuum line is clogged, and the reaction is often interrupted, or a large amount of volatile matter is generated, so the trap cannot remove the volatile matter, causing oligomers to mix in the oil of the vacuum pump, and reducing the pressure. The reaction time becomes remarkably lengthened. As a result, the heat history becomes longer, and the decomposition reaction of polyester further occurs to cause a vicious cycle in which the production of oligomers increases.

Further, the production of the oligomer itself means a marked decrease in the polyester yield, which results in an increase in cost and cannot be said to be an industrial production method.

Further, the pump for maintaining such a high vacuum is a special pump which is expensive, and the performance is remarkably deteriorated due to the scattering of oligomers.
It requires a lot of work for maintenance. In some cases, the reaction is interrupted once during the production, and the pump is often maintained, which is not very industrial.

The present invention has been made in order to solve the above-mentioned problems of the prior art. Therefore, the object of the present invention is to use a general-purpose pump, and by-products and solutions at a practical degree of reduced pressure. It is intended to provide a method for producing a high-molecular-weight aliphatic polyester industrially efficiently and economically by suppressing the generation of a low-molecular compound due to polymerization.

[0012]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a method for producing a high molecular weight aliphatic polyester by a process including a transesterification reaction, and as a result, (1)
Since the transesterification reaction is a reaction in which the molecular weight is increased by removing glycol from the reaction system, it is necessary to remove glycol from the reaction system as quickly as possible in order to obtain a high molecular weight aliphatic polyester. (2) If the glycol is not efficiently removed, the reaction time becomes long, and as a result, an undesirable side reaction such as thermal decomposition occurs and the amount of volatile components significantly increases due to the formation of oligomers. ) For these reasons, it has hitherto been considered that extremely high-vacuum reaction conditions are indispensable for removing glycol from the system. (4) Furthermore, by making the system high-vacuum, the equilibrium of the reaction forms an oligomer. We obtained the knowledge that it will be shifted in the direction of and it will be a vicious circle.

From these findings, in order to efficiently remove glycol from the system without applying a high vacuum to the transesterification reaction, the transesterification reaction is remarkably promoted by increasing the surface area of the contents of the reaction system. As a result, it was found that a high molecular weight aliphatic polyester can be obtained at a degree of reduced pressure which was considered to be impossible at all.
The present invention has been reached.

That is, the present invention has a number average molecular weight of 100.
A high molecular weight aliphatic polyester of 00-100,000,
A high-molecular-weight aliphatic polyester characterized by carrying out the transesterification reaction while maintaining the total amount of the contents in the reaction system at 70% or less of the inner volume of the reaction vessel when produced by a process including the transesterification reaction. Manufacturing method.

The "internal volume of the reaction vessel" in the present invention means a geometrical space volume in an empty state in which the contents such as raw materials and solvents used for the reaction of the reaction vessel and the reaction apparatus used for the production are not put. In general, it may indicate the volume of water when it is filled with water.

Furthermore, by carrying out the transesterification reaction at a reduced pressure within a reaction pressure range of 0.5 to 5.0 mmHg, glycol can be efficiently removed from the reaction system by using a general-purpose pump, It is preferable in that generation of low molecular weight compounds due to organisms and depolymerization can be suppressed to a low level.

The degree of pressure reduction of the reaction pressure in the present invention means a measured value of the pressure in the reaction system (usually in the reaction vessel).

The high molecular weight aliphatic polyester is obtained, for example, from an aliphatic dicarboxylic acid component having 2 to 6 carbon atoms and an aliphatic glycol component having 2 to 4 carbon atoms. The high molecular weight aliphatic polyester is obtained, for example, by a step including a ring-opening copolymerization of a cyclic acid anhydride containing succinic anhydride as a main component and a cyclic ether containing ethylene oxide as a main component.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention has a number average molecular weight of 1,000.
It is used for producing a high molecular weight aliphatic polyester of 0 to 100,000 by a process including a transesterification reaction. The method for obtaining a high molecular weight aliphatic polyester by a step including a transesterification reaction is not particularly limited, and examples thereof include a method for obtaining a high molecular weight aliphatic polyester by a dehydration condensation reaction and / or a transesterification reaction in the presence of a catalyst. As a specific production method thereof, for example, (i) a method of polycondensing a polybasic acid (or an ester thereof) and glycol (ii) a ring-opening polymerization of a cyclic acid anhydride and a cyclic ether, and then further polymerization The method of condensing etc. are mentioned.

Therefore, the high molecular weight aliphatic polyester raw material referred to in the present invention indicates, for example, in the case of the method (i), a polybasic acid (or its ester), a glycol and a catalyst, and in the case of the method (ii), A cyclic acid anhydride, a cyclic ether, and a catalyst are shown.

The polybasic acid used in the method (i) is selected from difunctional or higher polyvalent carboxylic acids or their anhydrides and trifunctional or higher oxycarboxylic acids.
In order to produce a polyester in which an acid component and an alcohol component are linearly bonded, two carboxyl groups are included in one molecule.
Are preferred.

Examples of the polybasic acid used in the method (i) include succinic acid, adipic acid, suberic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, octadecanedicarboxylic acid, dimer acid and their esters. As the acid anhydride, for example, succinic anhydride, maleic anhydride, itaconic anhydride, glutaric anhydride, adipic anhydride, citraconic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic dianhydride, benzophenone tetra Carboxylic dianhydride, butane-1,
2,3,4-tetracarboxylic dianhydride, maleic anhydride homopolymer, maleic anhydride-vinyl acetate copolymer,
Maleic anhydride-ethylene copolymer, maleic anhydride-
Isobutylene copolymer, maleic anhydride-isobutyl vinyl ether copolymer, maleic anhydride-acrylonitrile copolymer, maleic anhydride-styrene copolymer and the like, and trifunctional or higher oxycarboxylic acid as malic acid, tartaric acid , Citric acid and the like.

Examples of the glycol used in the method (i) include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6. -Hexanediol, decamethylene glycol and the like. It is also possible to use polyoxyalkylene glycol as a part of the glycol component, and examples thereof include polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol and copolymers thereof. It is also possible to use a trifunctional or higher polyhydric alcohol as a part of the glycol component, and examples thereof include glycerin, trimethylolpropane, and pentaerythritol. It is also possible to use diepoxides as part of the glycol component, eg (poly)
Ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, resorcin diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, adipic acid diglycidyl ester , Ο-phthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, hydroquinone diglycidyl ether, bisphenol S diglycidyl ether, glycerol diglycidyl ether, sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol poly Glycidyl ether, diglycerol polyglycidyl ether, tri Rishijirutorisu (2-hydroxyethyl) isocyanurate, glycerol triglycidyl ether, trimethylolpropane polyglycidyl ether. Of these, considering the melting point, biodegradability, and economic efficiency of the resulting polyester, an aliphatic dicarboxylic acid component having 2 to 6 carbon atoms and 2 to 2 carbon atoms
The combination with the aliphatic glycol component of 4 is preferable, and the combination of succinic acid and ethylene glycol and / or the combination of succinic acid and 1,4-butanediol is more preferable.

In the production of the high molecular weight aliphatic polyester, the polybasic acid (or its ester) component and the glycol component may all be initially mixed and reacted, or may be divided and added as the reaction progresses. It doesn't matter. As the polycondensation reaction, a normal esterification reaction is performed, and then the degree of polymerization is increased by a transesterification method.
At this time, the distinction between the esterification reaction and the transesterification reaction does not necessarily need to be clear.

The esterification and transesterification reactions usually require the use of small amounts of catalyst. When the esterification method and the transesterification reaction by dehydration condensation are used in combination,
It is also possible to carry out ester exchange reaction using a catalyst after carrying out esterification without a catalyst. As a catalyst,
There is no particular limitation as long as it is generally used.
i, Ge, Zn, Fe, Mn, Co, Zr, Hf, V,
Ir, La, Ce, Li, Ca, Mg, Sn, Ba, N
Examples thereof include organic metal compounds such as i, organic acid salts, metal alkoxides, metal oxides, metal hydroxides, carbonates, phosphates, sulfates, nitrates, chlorides and the like. The amount of the catalyst to be used is 0.001 to 5 parts by weight, preferably 0.01 to 0.5 parts by weight, based on 100 parts by weight of the usually obtained high molecular weight aliphatic polyester.

The cyclic acid anhydride used in the method (ii) may have one acid anhydride group in one molecule, or 2
Although it may have one or more, in order to produce a polyester in which an acid component and an alcohol component are linearly bonded, one having one acid anhydride group in one molecule is preferable. (I
Examples of the cyclic acid anhydride used in the method i) include succinic anhydride, maleic anhydride, itaconic anhydride, glutaric anhydride, adipic anhydride, citraconic anhydride, phthalic anhydride, trimellitic anhydride, and dianhydride. Pyromellitic acid, benzophenone tetracarboxylic dianhydride, butane-1,2,3,4-tetracarboxylic dianhydride, maleic anhydride homopolymer, maleic anhydride-vinyl acetate copolymer, maleic anhydride- Examples thereof include ethylene copolymers, maleic anhydride-isobutylene copolymers, maleic anhydride-isobutyl vinyl ether copolymers, maleic anhydride-acrylonitrile copolymers and maleic anhydride-styrene copolymers.

The cyclic ether used in the method (ii) may have one epoxy group in one molecule or 2
Although it may have one or more, one having one epoxy group in one molecule is preferable for producing an aliphatic polyester in which an acid component and an alcohol component are linearly bonded. Examples of the cyclic ether used in the method (ii) include ethylene oxide, propylene oxide, cyclohexene oxide, styrene oxide, epichlorohydrin, allyl glycidyl ether, phenyl glycidyl ether, tetrahydrofuran, oxepane, 1,
3-dioxolane, (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, resorcin diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-
Hexanediol diglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, hydroquinone diglycidyl ether, bisphenol S diglycidyl ether, glycerol diglycidyl ether, sorbitol polyglycidyl ether, sorbitan polyglycidyl Ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether,
Diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanurate,
Examples thereof include glycerol triglycidyl ether and trimethylolpropane polyglycidyl ether. Among these, a combination of succinic anhydride and ethylene oxide is preferable in consideration of the melting point, biodegradability and economic efficiency of the obtained polyester. The ring-opening polymerization can be carried out using a known ring-opening polymerization catalyst by a method such as polymerization in a solvent or bulk polymerization.

Among the methods for obtaining such a high molecular weight aliphatic polyester, as a method which can be industrially efficiently produced in a relatively short time, after ring-opening polymerization of the cyclic acid anhydride (ii) and the cyclic ether, A method of further polycondensing is preferable. The ring-opening polymerization of cyclic acid anhydride and cyclic ether will be described in more detail below.

It has been known so far that the cyclic acid anhydride such as succinic anhydride used in the present invention does not homopolymerize. By cyclically adding cyclic ether in the presence of a polymerization catalyst to such a cyclic acid anhydride that is not homopolymerized and polymerizing, a polyester in which an acid component and an alcohol component are substantially copolymerized alternately can be produced in a short time. Can be generated.

The polymerization can be carried out by a method such as polymerization in a solvent or bulk polymerization. In the polymerization in a solvent, the cyclic acid anhydride is dissolved in the solvent before use. In the bulk polymerization, the cyclic acid anhydride is melted before use in the present invention.

Polymerization in a solvent can be carried out batchwise or continuously, and the solvent used in this case is, for example, benzene, toluene, xylene, cyclohexane, n.
-Inert solvents such as hexane, dioxane, chloroform and dichloroethane may be mentioned.

The polymerization catalyst is not particularly limited, and those usually used for ring-opening polymerization of polyester are used. For example, tetramethoxy zirconium, tetraethoxy zirconium, tetra-iso-propoxy zirconium, tetra-iso-butoxy zirconium, tetra-n-butoxy zirconium, tetra-t-butoxy zirconium, triethoxy aluminum, triethoxy aluminum, tri-n-propoxy aluminum, tri- iso-propoxyaluminum, tri-n-butoxyaluminum, tri-i
So-butoxyaluminum, tri-sec-butoxyaluminum, mono-sec-butoxy-di-iso-
Propoxy aluminum, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), tetraethoxy titanium, tetra-iso-propoxy titanium, tetra-n-propoxy titanium, tetra-n-butoxy titanium, tetra-se.
c-butoxytitanium, tetra-t-butoxytitanium, tri-iso-propoxygallium, tri-iso-propoxyantimony, tri-iso-butoxyantimony, trimethoxyboron, triethoxyboron, triethoxyboron
iso-propoxybolone, tri-n-propoxyborone, tri-iso-butoxyborone, tri-n-butoxyborone, tri-sec-butoxyborone, tri-t-
Butoxyboron, tri-iso-propoxygallium,
Tetramethoxygermanium, tetraethoxygermanium, tetra-iso-propoxygermanium, tetra-n-propoxygermanium, tetra-iso-butoxygermanium, tetra-n-butoxygermanium, tetra-sec-butoxygermanium, tetra-
metal alkoxides such as t-butoxygermanium; antimony pentachloride, zinc chloride, lithium bromide, tin chloride (I
V), halides such as cadmium chloride and boron trifluoride diethyl ether; trimethylaluminum, triethylaluminum, diethylaluminum chloride, ethylaluminum dichloride, tri-iso-
Alkyl aluminum such as butyl aluminum; alkyl zinc such as dimethyl zinc, diethyl zinc, diisopropyl zinc; tertiary amine such as triallylamine, triethylamine, tri-n-octylamine, benzyldimethylamine; phosphotungstic acid, phosphomolybdic acid, silica Heteropoly acids such as tungstic acid and alkali metal salts thereof; zirconium oxychloride, zirconyl octylate, zirconyl stearate, zirconium compounds such as zirconyl nitrate and the like, among which zirconyl octylate, tetraalkoxy zirconium,
Trialkoxyaluminum compounds are particularly preferred. The amount of the polymerization catalyst used is not particularly limited, but is usually 0.001 to 1 based on the total amount of the cyclic acid anhydride and the cyclic ether.
0% by weight. Regarding the method of adding the polymerization catalyst, the polymerization catalyst may be added to the cyclic acid anhydride or may be added sequentially like a cyclic ether.

The polymerization temperature is not particularly limited as long as it is a temperature at which a cyclic acid anhydride and a cyclic ether react with each other.
° C, preferably 50 to 150 ° C, more preferably 10 ° C.
0-150 ° C. During the reaction, the pressure in the reaction vessel varies depending on the reaction temperature, the presence or absence of a solvent, and the type of solvent.However, the increase in unreacted cyclic ether due to the increase in pressure due to the sequential addition of cyclic ether increases the polyether content in the reaction product. It is not preferable because the ether component is increased. Therefore, the pressure in the reaction vessel is preferably atmospheric pressure to 50 kgf / cm ² , and more preferably cyclic ether is added so as to be atmospheric pressure to 15 kgf / cm ² .

Sequential addition of cyclic ether was carried out by adding 3 to 9 parts of cyclic ether to 100 parts by weight of cyclic acid anhydride per hour.
The amount is preferably 0 parts by weight, more preferably 5 to 50 parts by weight.

When the addition rate of the cyclic ether is lower than the lower limit of 3 parts by weight, the reaction is prolonged and the productivity is lowered, which is not industrially preferable. On the other hand, when the content is higher than the upper limit of 90 parts by weight, the polyether component in the reaction product increases and only polyester having a low melting point can be obtained.

The sequential addition of cyclic ether means that cyclic ether is not added all at once, and either a method of continuously dropping or a method of intermittently adding by dividing into multiple stages may be used. It is preferable to add continuously so that the amount of addition does not largely change over time.

The reaction ratio of the cyclic acid anhydride and the cyclic ether in the present invention is 40/60 to 6 in terms of their molar ratio.
The ratio is preferably 0/40. In view of the fact that the residual cyclic acid anhydride and the terminal carboxyl group of the polyester reduce the physical properties of the polyester, the ratio of 40/60 to 49/49 is added in order to add the cyclic ether in excess. / 5
More preferably, the ratio is 1. By doing so, less than 50% of the terminal carboxyl groups of the polyester become carboxyl groups, and heat resistance is improved.

If the ratio is out of this range, unreacted monomer may increase and the yield may decrease. In the present invention, it is preferable to continue the polymerization at the reaction temperature after the sequential addition of a predetermined amount of the cyclic ether determined in consideration of the molar ratio, and then to age it. The polyester formed from the polymerization system after the aging reaction may be separated.

Regarding the reaction conditions, for example, when a heavy (condensed) compound is obtained by the method (i), there is no problem as the known conditions for the esterification reaction. For example, reaction temperature 180
The reaction is carried out at a pressure of 280 ° C and a pressure of 1 mmHg to 1 mmHg to carry out a transesterification. The conditions for the transesterification reaction are a reaction temperature of 180 to 280 ° C., preferably 2
30-270 ° C, degree of vacuum 0.5-5.0 mmHg, preferably 1.0-3.0 mmHg, more preferably 1.0-
It is 2.0 mmHg. When the reaction temperature is lower than this range, the reaction time becomes remarkably long, and when it is higher than this range, the color is remarkably increased or the volatile content is increased,
Industrially disadvantageous. When the degree of reduced pressure exceeds 0.5 mmHg, that is, when a high vacuum is produced, a large amount of low molecular compounds due to byproducts and depolymerization are produced. Due to the decrease in the degree of pressure reduction due to the generation of these volatile components and the deterioration in the performance of the vacuum pump,
The reaction time becomes extremely long, and the molecular weight does not reach a predetermined value. Further, the yield is remarkably reduced due to generation of volatile components, and even if recovered, these volatile components are not used, and thus become a serious economic problem. When the degree of reduced pressure is lower than 5.0 mmHg, the reaction time becomes extremely long, which is industrially disadvantageous.

The reaction conditions for further polycondensation of the polymer obtained by the ring-opening polymerization of the method (ii) are:
Reaction temperature 180-280 ° C, preferably 230-270
C, degree of vacuum 0.5-5.0 mmHg, preferably 1.0-
It is 3.0 mmHg, more preferably 1.0 to 2.0 mmHg. When the reaction temperature is lower than this range, the reaction time becomes extremely long, and when the reaction temperature is higher than this range, it is industrially disadvantageous because of significant coloration and a large amount of volatile components. When the degree of reduced pressure is 0.5 mmHg or less, that is, when the vacuum is high, a large amount of by-products and low-molecular compounds due to depolymerization are produced. Due to the reduction in the degree of decompression and the performance of the vacuum pump due to the generation of these volatile components, the reaction time becomes extremely long or the molecular weight does not reach a predetermined value. Further, the yield is remarkably reduced due to generation of volatile components, and even if recovered, these volatile components are not used, and thus become a serious economic problem. When the degree of reduced pressure is lower than 5.0 mmHg, the reaction time becomes extremely long, which is industrially disadvantageous.

Further, in order to suppress the generated volatiles to a smaller amount throughout the entire process of producing the high molecular weight aliphatic polyester, it is necessary to include a process by ring-opening polymerization without formation of water or the like, that is, the method (ii). More preferable.

The high molecular weight aliphatic polyester thus obtained may be further reacted with various chain extenders to obtain a high molecular weight.

The number average molecular weight of the high molecular weight aliphatic polyester is 10,000 to 100,000, preferably 25,000 to 80,000, more preferably 40,000 to.
It is 70,000. In order to use the aliphatic polyester as a film, sheet or other molded product, the number average molecular weight is required to be at least 10,000 or more. If it is lower than this, there is an industrial problem such as brittleness or inability to be stretched, and it is possible to react with a chain extender to increase the molecular weight, but the process has multiple stages and the chain extender used May cause the fisheye of the film, which is industrially disadvantageous. Considering thermal deterioration and strength, the number average molecular weight of the high molecular weight aliphatic polyester is preferably 25,000 or more, more preferably 40,000 or more. Also,
The reaction takes a long time to increase the number average molecular weight to 100,000 or more, which is industrially disadvantageous. The number average molecular weight is 1000 because the volatile matter generated increases as the reaction proceeds for a long time.
00 or less, preferably 80,000 or less, 7,000
0 or less is more preferable.

According to the present invention, when the high molecular weight aliphatic polyester is produced by the process including the above-mentioned transesterification reaction, the total amount of the contents in the reaction system is 7% of the inner volume of the reaction vessel.
It is characterized in that the transesterification reaction is carried out while maintaining it at 0% or less, preferably 60% or less. When the inner volume of the reaction vessel is larger than 70%, it is not possible to secure a wide gas-liquid contact surface, and the reaction is performed at a reduced pressure level (usually 0.5 to 5.0 mmHg reduced pressure level) that can be achieved with a general-purpose pump. The time becomes extremely long, and it cannot be said to be an industrial manufacturing method. In addition, high vacuum (usually
If the degree of vacuum is less than 0.5), the amount of oligomers produced is increased, which is not preferable.

In producing the high molecular weight aliphatic polyester of the present invention, a known reactor can be used. Specifically, in a vertical reactor, when a flask or a reaction kettle equipped with an ordinary stirring device is used, the reaction is carried out while maintaining the content at 70% or less, preferably 60% or less of the inner volume of the reaction container. As a result, the surface area relative to the volume of the content is increased and a wide gas-liquid contact surface can be secured. Further, the surface area can be more efficiently increased in the reaction vessel equipped with the helical ribbon blade and the spirally deformable baffle. In a horizontal reactor, a horizontal uniaxial or biaxial kneading device in which agitation shafts connecting deformation blades are arranged side by side can efficiently increase the surface area.

Further, in order to efficiently carry out the transesterification reaction, it is necessary to make the glycol formed during the reaction easy to volatilize, that is, to enhance the free surface renewal property of the contents of the reaction system,
Since it is preferable to secure a wide gas-liquid contact surface (free surface area), it is preferable to use a reactor for high viscosity.

The reactor for high viscosity may be a batch type or a continuous type, and examples of the batch type include an inverted conical ribbon blade type reactor (manufactured by Mitsubishi Heavy Industries, Ltd.) and a twisted lattice blade type reactor (Hitachi Ltd.). Manufactured by Sumitomo Heavy Industries, Ltd., etc.,
In the continuous type, for example, Hitachi Glass Blade Polymerizer (manufactured by Hitachi, Ltd.), Hitachi Lattice Blade Polymerizer (manufactured by Hitachi Ltd.), Self-cleaning reactor (manufactured by Mitsubishi Heavy Industries, Ltd.),
Widely used for horizontal biaxial reactor (made by Mitsubishi Heavy Industries, Ltd.), KRC kneader (made by Kurimoto Iron Works, Ltd.), TEX-K (made by Japan Steel Works, Ltd.) and plastic extrusion or devolatilization. The single-screw or twin-screw extruder etc. which are used can be mentioned.

In the high molecular weight aliphatic polyester of the present invention, if necessary, other components such as crystal nucleating agent, pigment, dye, heat-resistant agent, antioxidant, weathering agent, lubricant, antistatic agent,
Stabilizers, fillers, reinforcing agents, flame retardants, plasticizers, other polymers and the like can be added within a range that does not impair the effects of the present invention.

The high molecular weight aliphatic polyester thus obtained can be applied to usual molding methods such as extrusion molding, injection molding, blow molding, vacuum molding, and various parts, containers, materials, instruments, It can be a molded product such as a film, a sheet, or a fiber.

[0050]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

The evaluation methods carried out in the examples are as follows. The results are summarized in Table 1.

(Internal volume) The weight of water when the separable flask was filled with water and the water became full was defined as the internal volume.

(Molecular weight) The number average molecular weight in terms of polystyrene was measured using a gel permeation chromatograph.

(Melting point) Measured by DSC.

(Biodegradability test) 130 ° C., 150 kg / c
A film having a thickness of 200 μm was prepared by a compression molding machine under the condition of m ² for 2 minutes, and the obtained film was embedded in a soil-filled planter and watered once a day at 23 ° C.
The sample was stored in a thermo-hygrostat having a relative humidity of 65% and the appearance change after 100 days was observed.

The soil used was that collected from Onohara in Minoh City and Nishiomitabi Town in Suita City, and a mixture of mulch at a ratio of 3: 1: 3.

The results are described below.

(+): A change in appearance was observed.

(-): No change in appearance was observed. (Example 1) A succinic anhydride was placed in a three-necked flask equipped with a stirrer, a Wigrew fractionation tube equipped with a trap immersed in dry ice-methanol at the outlet, and a gas introduction tube.
0.08 g and 76.63 g of ethylene glycol were added and immersed in an oil bath. The temperature of the oil bath is raised, nitrogen is slowly flown, and the water and excess ethylene glycol that are produced in 52 hours at a temperature of 185 ° C. and a pressure reduction degree of atmospheric pressure to 1.0 mmHg are distilled off to obtain a polyester having a number average molecular weight of 6000. (A) was obtained.

Then, the obtained polyester (a) 1
0.79 g and tetra-n-butyl titanate 0.000
4 g and a separable flask equipped with a thermometer, a stirrer and a nitrogen inlet tube (internal volume 174.3 ml)
In addition, after performing nitrogen replacement three times, under a reduced pressure of 1.0 to 1.1 mmHg (in a separable flask) with a vacuum pump equipped with a trap immersed in dry ice-methanol in a nitrogen stream, a temperature of 240 ° C. React for 5.0 hours under the conditions of
A high molecular weight aliphatic polyester (1) was obtained. The number average molecular weight measured by GPC was 65,000, and the melting point measured by DSC was 104.6 ° C. The volatile matter attached to the upper part of the trap and the three-necked flask was 7.2% by weight based on the charged polyester.

During the reaction, the vacuum line was not clogged and the performance of the vacuum pump was not deteriorated.

(Example 2) 200.14 g of succinic anhydride and ethylene glycol were placed in a three-necked flask equipped with a stirrer, a Wigrew fractionating tube equipped with a trap immersed in dry ice-methanol at the outlet, and a gas introduction tube. 248.
28 g, and tetra-n-butyl titanate 0.36 g
And put it in an oil bath. Raise the temperature of the oil bath,
Slowly flush nitrogen, temperature 200 ℃, normal pressure ~ 10.0mm
Water and excess ethylene glycol produced in 17 hours under a reduced pressure of Hg were distilled off to obtain a polyester (b) having a number average molecular weight of 5,500.

Then, the obtained polyester (b) 1
0.10 g and tetra-n-butyl titanate 0.007
9 g and a separable flask equipped with a thermometer, a stirrer and a nitrogen inlet tube (internal volume 174.3 ml)
In addition, after performing nitrogen replacement three times, under a reduced pressure of 1.1 to 1.2 mmHg (in a separable flask) with a vacuum pump equipped with a trap immersed in dry ice-methanol in a nitrogen stream, a temperature of 240 ° C. React for 3.5 hours under the conditions of
A high molecular weight aliphatic polyester (2) was obtained. The number average molecular weight measured by GPC was 74000, and the melting point measured by DSC was 104.1 ° C. The volatile matter attached to the upper part of the trap and the three-necked flask was 9.6% by weight based on the charged polyester.

During the reaction, the vacuum line was not clogged and the performance of the vacuum pump was not deteriorated.

Example 3 100.1 g of succinic anhydride and zirconyl octylate 2.9 were placed in an autoclave.
9 g was added and the atmosphere was replaced with nitrogen. Then, the autoclave is gradually heated to 130 ° C. with stirring to melt the succinic anhydride, and the pressure in the autoclave is adjusted to 4.0 to 4.0 at the same temperature.
While maintaining at 8.1 kgf / cm ² , ethylene oxide 231.
26 g was continuously introduced over a period of 5.5 hours at an addition rate of 42 g per hour. After introducing ethylene oxide 130
A polyester (c) was obtained by carrying out an aging reaction at 1.0 ° C. for 1.0 hour and then returning the system to room temperature. The number average molecular weight measured by GPC is 11,400, and the melting point measured by DSC is 1.
It was 03.1 ° C.

9.67 g of the polyester (c) thus obtained was added to a separable flask (internal volume: 175.7 ml) equipped with a thermometer, a stirrer and a nitrogen inlet tube, and the atmosphere was replaced with nitrogen three times. 1.0 in a vacuum pump equipped with a trap immersed in dry ice-methanol in an air stream
Under a reduced pressure of ~ 1.2 mmHg (in a separable flask), the reaction was carried out at a temperature of 240 ° C for 3.0 hours to obtain a high molecular weight aliphatic polyester (3). The number average molecular weight measured by GPC was 63400, and the melting point measured by DSC was 103.
5 ° C. In addition, the volatile matter attached to the upper part of the trap and the three-necked flask was 5.
It was 9% by weight.

During the reaction, the vacuum line was not clogged and the performance of the vacuum pump was not deteriorated.

Example 4 45.4 g of the polyester (c) obtained in Example 3 was added to a separable flask equipped with a thermometer, a stirrer and a nitrogen inlet tube (internal volume 172.3).
Milliliter), and after performing nitrogen replacement 3 times,
2. A vacuum pump equipped with a trap immersed in dry ice-methanol in a nitrogen stream under a reduced pressure of 1.1 to 1.2 mmHg (in a separable flask) and a temperature of 240 ° C.
The reaction was carried out for 2 hours to obtain a high molecular weight aliphatic polyester (4). Number average molecular weight measured by GPC is 36000, D
The melting point measured by SC was 103.0 ° C. Also,
The volatile matter attached to the upper part of the trap and the three-necked flask was 7.2% by weight based on the charged polyester.

During the reaction, the vacuum line was not clogged and the performance of the vacuum pump was not deteriorated.

Example 5 To a 100 liter autoclave, 50.2 kg of succinic anhydride and 0.296 kg of zirconyl octylate were added, and the atmosphere was replaced with nitrogen.
Then, the temperature of the autoclave was gradually raised to 130 ° C. under stirring to melt the succinic anhydride, and while maintaining the pressure inside the autoclave at 3.5 to 9.9 kgf / cm ² , 23.2 kg of ethylene oxide. Was continuously introduced for 5.0 hours at an addition rate of 4.64 kg per hour to carry out the first-stage reaction. After the introduction of ethylene oxide, aging reaction at 130 ° C for 1.0 hour, and then returning the system to room temperature,
Polyester (d) was obtained. The number average molecular weight measured by GPC was 23100, and the melting point measured by DSC was 103.1 ° C.

Obtained polyester (d) 45.0k
g, diphenyl phosphite 0.450k as antioxidant
g and 1.80 kg of talc as a crystal nucleating agent were added to a high-viscosity reactor equipped with a thermometer, a stirrer, and a nitrogen introducing tube (“Super Blend” manufactured by Sumitomo Heavy Industries, Ltd., internal volume: 100 liters). After performing nitrogen replacement three times, a vacuum pump equipped with a trap immersed in dry ice-methanol under a reduced pressure of 1.6 to 3.1 mmHg (in the reactor) and a temperature of 280 ° C. For 2.0 hours and further at a temperature of 240 ° C. for 2.0 hours to carry out a second-stage reaction to obtain a high molecular weight aliphatic polyester (5). Number average molecular weight measured by GPC is 63200, DS
The melting point measured by C was 100.8 ° C. The volatile matter attached to the trap and the upper part of the three-necked flask was 4.1% by weight based on the charged polyester. Table 1 shows the above measurement results and test results.

During the reaction for obtaining the polyester (d) and the reaction for obtaining the high molecular weight aliphatic polyester (5), the vacuum line is not clogged and the performance of the vacuum pump is not deteriorated during the reaction. It was

(Comparative Example 1) 125.0 g of the polyester (c) obtained in Example 3 was added to a separable flask (internal volume 172.3 ml) equipped with a thermometer, a stirrer and a nitrogen introducing tube, and nitrogen was added. After performing the replacement three times, in a nitrogen stream, with a vacuum pump equipped with a trap immersed in dry ice-methanol, under a reduced pressure of 1.0 to 1.2 mmHg (in a separable flask) and a temperature of 240 ° C., 7 The reaction was carried out for 5 hours to obtain comparative polyester (1). The number average molecular weight measured by GPC was 20,500, and the melting point measured by DSC was 103.1 ° C. The volatile matter attached to the upper part of the trap and the three-necked flask was 10.4% by weight based on the charged polyester. Table 2 shows the above measurement results and test results.

[0074]

[Table 1]

[0075]

[Table 2]

[0076]

According to the present invention, by-products and depolymerization of a biodegradable high-molecular-weight aliphatic polyester can be carried out at a practical degree of reduced pressure without using a high vacuum and a general-purpose pump can be used. It is possible to suppress the generation of a low molecular weight compound due to the above, and it is possible to manufacture with high yield, industrial efficiency, and economically.

Since the high molecular weight aliphatic polyester obtained in the present invention has a relatively high molecular weight and a high melting point with almost no polyether component in the structure, it can be easily molded into a film or sheet, It also has excellent durability as a molded product. Therefore, the high molecular weight aliphatic polyester obtained in the present invention can be effectively used for disposable packaging materials, daily sundries and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norihiro Shiroshima 5-8 Nishimitabicho Suita City, Osaka Prefecture Nippon Shokubai Co., Ltd.

Claims (4)

[Claims] 1. A number average molecular weight of 10,000 to 100,000.
In producing the high-molecular-weight aliphatic polyester of (1) by a process including a transesterification reaction, the transesterification reaction may be carried out while maintaining the total amount of the contents in the reaction system at 70% or less of the inner volume of the reaction vessel. A method for producing a high molecular weight aliphatic polyester, which is characterized. 2. The transesterification reaction is carried out at a reaction pressure of 0.
The method for producing a high molecular weight aliphatic polyester according to claim 1, which is carried out at a reduced pressure in the range of 5 to 5.0 mmHg. 3. The high molecular weight aliphatic polyester comprises an aliphatic dicarboxylic acid component having 2 to 6 carbon atoms and 2 carbon atoms.
The method for producing a high molecular weight aliphatic polyester according to claim 1 or 2, which is obtained from the aliphatic glycol component according to any one of (4) to (4). 4. The high molecular weight aliphatic polyester is obtained by a process comprising ring-opening copolymerization of a cyclic acid anhydride containing succinic anhydride as a main component and a cyclic ether containing ethylene oxide as a main component. The method for producing a high molecular weight aliphatic polyester according to claim 1 or 2.