JP2001026643A - Preparation of aliphatic-aromatic polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preparation process of a polyester which gives a high reaction rate at melt polymerization, yields an aliphatic-aromatic polyester having a high degree of polymerization without using any chain extender, inhibits side reactions at molding, allows little deterioration in physical properties of a product and generates little amount of THT gas. SOLUTION: In a preparation process of an aliphatic-aromatic polyester, a glycol component essentially comprising an aliphatic glycol and/or alicyclic glycol is melt polymerized with a dicarboxylic acid component essentially comprising an aliphatic dicarboxylic acid (a) and an aromatic dicarboxylic ester of a lower alkyl (b) in a molar ratio of 0.2<=(a)/[(a)+(b)]<=0.9 in the presence of [A] a titanium compound and [B] a compound of a IIA group metal of the periodic table as polymerization catalysts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel polyester, and more particularly, to an aliphatic aromatic polyester which is capable of melt-polymerizing at a relatively low temperature under a combination of a specific polymerization catalyst, The present invention relates to a method for producing an aliphatic aromatic polyester formed using 1,4-butanediol, succinic acid and / or adipic acid, and terephthalic acid as components.

[0002]

2. Description of the Related Art Polyethylene, which is the most typical plastic, has excellent properties and has been used in a great number of fields. However, it is generally considered that it does not biodegrade. It is said that it has a bad effect on the environment. Therefore, in recent years, as the environmental problems have become more severe, polyethylene has similar properties in mechanical properties, and aliphatic aromatic polyesters that are said to have biodegradability have attracted attention.
Polybutylene succinate terephthalate and / or polybutylene adipinate terephthalate-based polyesters have been developed to replace polyethylene.

For example, Witt et al. Have developed 1,4-butylene adipinate terephthalate as a biodegradable aliphatic aromatic polyester, and similar polyesters have been reported by BASF and Eastman Kodak. ing. However, in the conventionally proposed polymerization method, the polymerization activity of the catalyst is low, so that a high polymer is not generated, so that the viscosity does not increase, and the obtained aliphatic aromatic polyester cannot be formed into an inflation film. There was a problem. For example, Witt (GBF) et al. Polymerized at 190 ° C. for 36 hours using a Zn compound (W
O 96/07687 (PCT / EP95 / 02722)), and in the case of BASF, Sn compounds are used (WO 96/025446 (PCT /
EP 96/00457)), however, these Zn and Sn compounds have a low polymerization rate and cannot produce a high-polymer polyester. In addition, the resulting polyester has few terminal COOH groups,
In some cases, there was no terminal vinyl group, and the degree of biodegradability was low.

[0004] DE 19640269 (BASF) and US
P 5,446,079 (Eastman) uses Ti (OBu) ₃ and Ti (O
Polymerization is performed using a Ti-only catalyst such as iPr) ₃ . However, the method for producing an aliphatic aromatic polyester using a Ti-only catalyst has a problem that the polymerization activity is low and the polymerization rate is low, and further, side reactions occur frequently during polymerization and it is difficult to produce a high molecular weight polymer. There was also a disadvantage that the color tone of the produced polyester was poor. In addition, in the aliphatic aromatic polyester obtained by such a method, side reactions frequently occur during molding, and as a result, the main chain is cut off during molding, or the number of terminal COOH groups is greatly increased, so that the physical properties of the product (mechanical properties and resistance to (Hydrolyzability). In the method using the Ti alone catalyst system, if the Ti content is increased to increase the polymerization rate, the resulting polyester causes a side reaction such as main chain breakage during molding and deteriorates the physical properties, so the Ti content has to be reduced to a small amount. Therefore, it seems that a vicious cycle of increasing the degree of polymerization does not occur. On the other hand, Shirahama (Hiroshima University) et al. Reported that a chain extender was used to increase the degree of polymerization of an aliphatic aromatic polyester (No. 47).
(In Japanese) 3024-3025 ('98)), and an example in which diisocyanate is used as a chain extender to produce a polymer having a high degree of polymerization has been reported (DE19640269).

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyester having a high polymerization rate without adding a chain extender, and a low viscosity when melted. A polyester having a high degree of polymerization can be produced, and further, a side reaction during the polymerization reaction is suppressed, so that a production method capable of easily obtaining a high polymer is provided. Aromatic polyester which has the advantage that the main chain breakage is unlikely to occur, the physical properties of the product are less likely to be reduced, and the amount of gas generated is smaller because less tetrahydrofuran is formed as a by-product during molding. It is to provide a manufacturing method of.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its gist is to provide a glycol mainly composed of an aliphatic glycol and / or an alicyclic glycol. A component and a dicarboxylic acid component mainly composed of an aliphatic dicarboxylic acid (a) and a lower alkyl ester of an aromatic dicarboxylic acid (b), as a polymerization catalyst, [A] a titanium compound and [B] a metal compound of Group IIA of the periodic table. A process for producing an aliphatic aromatic polyester, which is characterized in that melt polymerization is carried out in the presence of a polyester.

In a preferred embodiment of the method of the present invention, the ratio (molar ratio) of the aliphatic dicarboxylic acid (a) to the aromatic dicarboxylic acid lower alkyl ester (b) is 0.2 ≦.
(A) / [(a) + (b)] ≦ 0.9 or 0.3 ≦
(A) / [(a) + (b)] ≦ 0.7; the aliphatic glycol component is mainly 1,4-butanediol, and the alicyclic glycol component is mainly cyclohexane. Dimethanol; the aliphatic dicarboxylic acid is mainly succinic acid and / or adipic acid, and the aromatic dicarboxylic acid lower alkyl ester is mainly terephthalic acid lower alkyl ester; [B] Periodic Table IIA The metal compound of the group III is a magnesium compound; the amount of the magnesium compound used is 0.1 [equivalent ratio] as magnesium with respect to titanium of the titanium compound [A].
A glycol component mainly composed of 1,4-butanediol; an aliphatic dicarboxylic acid component mainly composed of succinic acid and / or adipic acid; and a lower aromatic dicarboxylic acid mainly composed of dimethyl terephthalate. A method for producing an aliphatic aromatic polyester produced from an alkyl ester component is exemplified.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The aliphatic and alicyclic glycol components used in the present invention are not particularly limited as long as they are aliphatic and alicyclic compounds having at least two OH groups. However, it is particularly preferable to use 1,4-butanediol, 1,3-propylene glycol, and 1,4-cyclohexanedimethanol as main components. Among them, it is particularly preferable to use 1,4-butanediol as a main component, but other glycols such as ethylene glycol, 1,3-propylene glycol, neopentyl glycol, 1,6-hexamethylene glycol, and Methylene glycol, 1,4-chlorohexanedimethanol,
One or two or more alkylene glycols such as diethylene glycol, triethylene glycol, poly (oxy) ethylene glycol, polytetramethylene glycol, and polymethylene glycol may be mixed, and may be arbitrarily selected depending on the purpose. Further, a small amount of a polyhydric alcohol component such as glycerin may be used, and a small amount of an epoxy compound may be used to create a branched structure.

In the present invention, aliphatic dicarboxylic acids and lower alkyl esters of aromatic dicarboxylic acids are used as the dicarboxylic acid component, and terephthalic acid is the main component as the dicarboxylic acid of the lower alkyl esters of aromatic dicarboxylic acids. It is preferable to add a small amount of an aromatic dicarboxylic acid such as isophthalic acid, naphthalenedicarboxylic acid or diphenyldicarboxylic acid. The lower alkyl ester component is mainly composed of methyl ester, but may be one or more of ethyl ester, propyl ester, butyl ester and the like, and may be arbitrarily selected depending on the purpose. Specifically, the lower alkyl ester component of aromatic dicarboxylic acid preferably contains dimethyl terephthalate as a main component.

The aliphatic dicarboxylic acid component used in the present invention preferably contains adipic acid and / or succinic acid as a main component. In some cases, a small amount of an aliphatic dicarboxylic acid such as sebacic acid or oxalic acid can be added, but it is preferable not to add it from the viewpoint of the crystallization speed. In the method of the present invention, it is preferable to use a dicarboxylic acid component composed of an aliphatic dicarboxylic acid mainly composed of adipic acid and / or succinic acid and a lower alkyl ester of an aromatic dicarboxylic acid mainly composed of dimethyl terephthalate.

The charge ratio (molar ratio) of the aliphatic dicarboxylic acid component (a) and the aromatic dicarboxylic acid lower alkyl ester component (b) is usually 0.2 ≦ (a) / [(a) + (b) ]
Within the range of ≦ 0.9, it can be changed according to the desired physical properties of the produced polyester, but preferably 0.3 ≦ (a) / [(a) +
(b)] ≦ 0.7. When the charge ratio exceeds this range and is larger than 0.9, the polymerization rate is decreased, which is not preferable. On the other hand, when the charge ratio is smaller than 0.2, the biodegradability of the produced polyester is decreased, which is not preferable.

The aliphatic aromatic polyester in the present invention is defined as an aliphatic and / or alicyclic glycol component having at least two OH groups and at least two carboxylic acids as main monomers forming the polyester. It is a polyester produced using an aliphatic carboxylic acid having a group and an aromatic carboxylic acid ester. Specifically, when 1,4-butanediol is used as the glycol component, succinic acid or adipic acid is used as the aliphatic carboxylic acid, and dimethyl terephthalate is used as the aromatic carboxylic acid ester, the content is usually 75 mol% or more. 1,4-
A polyester having a butylene succinate terephthalate bond or a polyester having a 1,4-butylene adipinate terephthalate bond is preferred.
A polyester having 0,1 mol% or more of 1,4-butylene succinate terephthalate bond or a polyester having 1,4-butylene adipinate terephthalate bond, more preferably 90 mol% or more of 1,4-butylene succinate terephthalate bond Or a polyester having 1,4-butylene adipinate terephthalate bond. Most preferably, it is a polyester having 1,4-butylene succinate terephthalate bond of 95 mol% or more or a polyester having 1,4-butylene adipinate terephthalate bond.

When a polyester having a branched structure is desired, a small amount of an oxycarboxylic acid such as glycolic acid or lactic acid or a lactone such as caprolactone may be used.
It is preferable not to use it from the viewpoint of the crystallization speed and the melting point. Further, a trifunctional or higher functional acid anhydride or carboxylic acid such as a trifunctional or higher functional hydroxy compound, oxycarboxylic acid, trimellitic anhydride, and pyromellitic anhydride may be used.
According to the method of the present invention, a predetermined degree of polymerization can be achieved without using a chain extender.
A chain extender such as diphenyl carbonate or dioxazoline may be used. In particular, when diphenyl carbonate is used, 20% or less (preferably 10% or less)
It is, of course, preferable to add polyester carbonate. It is also possible to add a small amount of peroxide to increase the melt tension. Further, in order to enhance the hydrophilicity of the formed polyester, a compound having a hydrophilic group such as a sulfone group, a phosphate group, an amino group, and a nitrate group may be used, and these hydrophilic groups may be introduced. 4-sulfonated as a compound to obtain
-2,6-isophthalic acid and the like.

The titanium compound [A] used as a polymerization catalyst in the present invention includes potassium titanium oxalate, titanium halide, titanium carbonate, tetraalkyl titanate and the like. Among them, a tetraalkyl titanate (tetraalkoxy titanium) is preferable, and specifically, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-t-butyl titanate, tetraphenyl titanate, Cyclohexyl titanate, tetrabenzyl titanate, or a mixed titanate thereof. Among these, especially tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-
Butyl titanate is preferred, and tetra-n-butyl titanate is most preferred. In addition, 2 of these titanium compounds
More than one species may be used in combination. The amount of the titanium compound added is 30% based on the amount of the produced titanium.
-300 ppm, preferably 40-200 ppm, particularly preferably 50-150 ppm.

Examples of the Group IIA compound [B] used in the present invention include compounds such as Mg, Zn, and Ca. Of these, magnesium compounds are preferred in view of activity. These compounds include acetates, carbonates, hydroxides, oxides, alkoxides and the like, and among them, acetates are preferred in view of solubility. Specific examples of the magnesium compound include magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, magnesium hydrogen phosphate, and the like.Magnesium acetate or magnesium hydroxide is preferable, and particularly, the polymerization rate and 1, 4
-Magnesium acetate is preferred from the viewpoint of solubility in butanediol (foreign matter formation).

Although the amount of the magnesium compound to be added is not particularly limited, it is 0.1 to 10 in terms of magnesium (equivalent ratio), that is, Mg / Ti ratio with respect to the titanium compound.
Times the molar amount, particularly preferably from 0.3 to 5, more preferably from 0.5 to 3 times.
Is most preferred. When Mg / Ti <0.1, the improvement in the polymerization rate is small, the concentration of terminal COOH groups in the formed polyester is increased, and the color tone is undesirably deteriorated. On the other hand, when Mg / Ti> 10, the polymerization rate is decreased, and the hydrolysis resistance and color tone of the formed polyester are also deteriorated.

According to the present invention, in the production of an aliphatic aromatic polyester, a titanium compound and a Group IIA compound [B], particularly a magnesium compound, are used, and the amount of magnesium in the magnesium compound relative to the amount of titanium in the titanium compound is specified. By reducing the amount of the titanium compound to be used as a proportion, and simultaneously reducing the reaction temperature in the melt polymerization, that is, to less than 260 ° C., the terminal COOH by the side reaction of the polymer obtained without reducing the polymerization rate. A high molecular weight polyester excellent in hydrolysis resistance, heat resistance, and color tone is obtained, and side reactions during molding are suppressed, so that the mechanical properties are reduced. It is based on the finding that it has a characteristic that the amount of gas generation during molding is also small.

According to the method of the present invention, a polymer having a high polymerization activity and an improved intrinsic viscosity can be realized. This is because the addition of a Group IIA compound, especially a magnesium compound, causes an interaction between the magnesium compound and the titanium compound, and changes the coordination / bonding structure of the titanium catalyst.
This is presumably because a specific structure that facilitates the generation of a specific active site of the main reaction such that the molecule of the reaction raw material can interact with the titanium atom is formed, and the acid-base property of the titanium catalyst is changed by the interaction. This means that the near-X-ray absorption edge structure (XANES, X-ray Absorption) is used.
n Near-Edge Structure). In the XANES spectrum of poly (1,4-butylene succinate terephthalate), the preedge peak (4.965 to 4.972 keV) attributed to the transition process of titanium from 1s to 3d orbitals.
The intensity of the (main peak near) is larger when the magnesium compound is added. This is evidence that the point-symmetric octahedral structure of the coordination / bonding atom near the titanium element is distorted, and it is estimated that the number of coordination to titanium is reduced, so that the reactant molecules can interact with the titanium atom. It is presumed that an active site is created.

Further, in the combination catalyst of the present invention,
Non-uniform specific strong acidic sites of Ti can be suppressed, and generation of unnecessary by-products can be suppressed. That is, the acidity of a specific site of the titanium catalyst is suppressed by the interaction between the magnesium compound and the titanium compound due to the addition of the group IIA compound, especially the magnesium compound (this is also XANES
As a result, unnecessary by-products and side reactions are suppressed. Unnecessary by-products and side reactions mentioned here include, for example, tetrahydrofuran (TH) by various decomposition reactions of terminal hydroxybutyl groups when 1,4-butanediol is used as a glycol component.
F) and accompanying generation of terminal COOH groups and / or vinyl groups of poly (1,4-butylene succinate terephthalate) and / or poly (1,4-butylene adipinate terephthalate), and generation of ester groups There are generation of a carboxyl group and a decrease in molecular weight due to a decomposition reaction.
Further, when 1,3-propylene glycol is used, allyl alcohol is generated by various decomposition reactions of the terminal hydroxypropyl group and generation of a terminal vinyl group, and when cyclohexanedimethanol is used, vinylidene terminal is used. Side reactions such as the formation of a methyl group or a terminal methylcyclohexene group are likely to occur.

The electronic state of Ti related to the specific acid-base property of Ti is shown in the XANES region of XAFS.
The K absorption edge jump around 4.98 keV of Ti is mainly 2
Types, including the high energy side (4.982 keV
Near) and low energy side (4.978keV)
There is a jump in the vicinity), but the difference in slope between the two indicates the difference in the strength of the two transitions on the low energy side and the high energy side. Ratio of the slope of the low-energy side jump for the slope of the high-energy side jump (easy compared to see at a rate R ₂ of the maximum slope.) Is how strong transitions low energy side is the transition of the high-energy side It is a measure of whether it is. In general, when the electron density of the element to be measured increases, the position of the absorption edge jump shifts to a lower energy side. Therefore, this R ₂ suppresses the specific electron density of Ti and the acidity of the specific site of Ti. Indicates the degree. The present invention relates to a poly (1,4-) having a higher value of R _{2 of} XANES, which indicates the degree of suppression of the acid property of a specific site of Ti, than a catalyst catalyzed only by tetrabutyl titanate.
Butylene succinate terephthalate) and / or poly (1,4-butylene adipinate terephthalate)
It has good polymerization activity in which unnecessary by-products are suppressed, resulting in hydrolysis resistance (including products after melt molding),
Based on the knowledge that thermal stability (including products after melt molding), color tone, etc. are good, low gas properties during molding, and suppression of deterioration in physical properties of products due to suppression of main chain breakage are achieved. is there.

In the present invention, the reaction temperature (internal temperature) in melt polymerization is not particularly limited as long as it is 220 ° C. or higher.
It is appropriately selected according to the desired physical properties of the produced polyester.
If you want to increase the number of terminal COOH groups in the resulting polyester,
It is important that the internal temperature at a temperature exceeding 40 ° C., particularly at the end of the melt polymerization (end stage), be higher than 240 ° C.
50 ° C. or higher is preferred. In this case, since the melt polymerization rate is high, additional charging can be performed, which can contribute to improvement in productivity. If you want to improve the color tone and reduce the number of terminal COOH groups and vinyl groups,
It is preferable to carry out at 40 ° C. or lower. More preferably 23
The temperature is 5 ° C or lower, more preferably 230 ° C or lower.

As described above, the present invention uses a titanium compound and a Group IIA compound, particularly a magnesium compound, in the production of polyester, and adjusts the amount of magnesium in the magnesium compound to the amount of titanium in the titanium compound to a specific ratio. By reducing the amount of the titanium compound used and, at the same time, making the reaction temperature in the melt polymerization relatively low, that is, at least 250 ° C., the terminal carboxyl groups and vinyl groups of the polyester polymer obtained without reducing the polymerization rate are increased. This makes it possible to obtain a polyester excellent in hydrolyzability and biodegradability.

In the present invention, a transesterification reaction between an alkylene glycol component containing a 1,4-butylene glycol component as a main component and a lower alkyl ester of an aromatic dicarboxylic acid containing a dimethyl terephthalate component as a main component, and A process in which an alkylene glycol component containing a 4-butylene glycol component as a main component and an esterification reaction with adipic acid or succinic acid are simultaneously performed, and a polyester is produced through a subsequent polycondensation reaction step. The reaction conditions are not particularly limited except for the polymerization catalyst and the temperature at the time of melt polymerization, and known reaction conditions can be applied as they are.

For example, the molar ratio of (alkylene glycol component / aromatic dicarboxylic acid lower alkyl ester component) in the transesterification reaction is 2.0 or less, preferably 1.0 to 1.0.
1.6, and the molar ratio of (alkylene glycol component) / (aliphatic dicarboxylic acid component) in the esterification reaction is 2.0.
Hereinafter, it is preferably 1.1 to 1.6. The temperature in the step in which the transesterification reaction and the esterification reaction proceed simultaneously is usually 120 to 245 ° C, preferably 140 to 230 ° C.
C. for 2-4 hours. Next, a polycondensation reaction is carried out, usually under reduced pressure of 3 torr or less under 25 torr.
0 ° C. or higher, preferably 255 ° C. or higher, more preferably 2 ° C.
It is 60 ° C or more and 275 ° C or less. The polymerization time is 2 to
10 hours. In the present invention, it is important to maintain the polycondensation temperature at 250 ° C. or higher, and in particular, in the late stage of polymerization in which the degree of polymerization increases, torque may be increased due to high viscosity. Must be controlled to 250 ° C. or higher.

The addition time of the titanium compound is determined by transesterification.
At the start of the esterification reaction, during the reaction, after the reaction, at the time of the polycondensation, etc., it is preferable to add separately at the start of the transesterification / esterification reaction and before the polycondensation reaction. The timing of addition of other additives such as magnesium compound
At the start of the esterification reaction, during the reaction, after the reaction, at the time of polycondensation, etc., at the end of the transesterification / esterification reaction,
It is preferable to add it before the start of polymerization in terms of polymerization activity and color tone. When succinic acid and / or adipic acid and dimethyl terephthalate are used as main components, it is preferable to add a titanium compound and a magnesium compound during the polycondensation reaction. In this case, a tin compound or a zinc compound may be added at the time of a reaction such as esterification or at the time of polymerization, but the color tone may be slightly deteriorated in some cases. According to the production method of the present invention, the polymerization rate is greatly improved as compared with the conventional method, so that the productivity can be further improved by increasing the charge amount. On the other hand, the charge amount can be reduced, and as a result, the terminal COOH group concentration can be further reduced, and the color tone can be further improved.

In addition, various additives such as a heat stabilizer, an antioxidant, a crystal nucleating agent, a flame retardant, an antistatic agent, a release agent, and an ultraviolet absorber as long as the properties of the aliphatic aromatic polyester are not impaired. May be added at the time of polymerization. In addition to the various additives shown above during molding, glass fiber, carbon fiber, titanium whisker, mica, talc, CaCO ₃ , TiO
_2. Molding may be carried out by adding a reinforcing agent such as silica or an extender.

The aliphatic aromatic polyester obtained by the method of the present invention is excellent in heat resistance, color tone, hydrolysis resistance and biodegradability, and can be produced at low cost. Suitable for use in molded articles. Its applications include injection molded products (for example, fresh food trays and fast food containers, outdoor leisure products, etc.), extruded products (films and sheets, such as fishing line, fishing net, vegetation net, water retention sheet, etc.), hollow Examples include molded articles (bottles and the like) and the like, and are also used for other applications such as agricultural coating materials and fertilizer coating materials.

[0028]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In addition, "part" in the examples
Certain items represent "parts by weight", and each physical property was evaluated by the following methods. (1) The reduced viscosity (η _sp / c) is determined from the solution viscosity of an aliphatic aromatic polyester measured in phenol / tetrachloroethane (1: 1 weight ratio) at 30 ° C. at a solution concentration (0.5 dl / g). It is what I sought. (2) The terminal carboxyl group [COOH] is prepared by dissolving an aliphatic aromatic polyester in benzyl alcohol and adding 0.1 N
It is a value titrated with NaOH, and is a carboxyl group equivalent per 1 × 10 ⁶ g.

(3) The terminal vinyl group was prepared by dissolving an aliphatic aromatic polyester in hexafluoroisopropanol / deuterated chloroform = 3/7 (vol ratio),
It is a value measured by HzH-NMR and is a vinyl group equivalent per 1 × 10 ⁶ g. (4) Evaluation of thermal stability was conducted by placing an aliphatic aromatic polyester in a test tube with a branch, viscosity (η _sp / c) after heat treatment (melt heat stability test) at 260 ° C. for 30 minutes under N ₂ , COOH
Groups were measured and the viscosity (η _sp /
c) and the amount of terminal COOH groups. That is, the viscosity retention rate
(%) = {[(Η _sp / c after melt heat stability test) / (η _sp / c before melt heat stability test)] × 100} and the difference between terminal COOH groups (OHCOOH) = [( Terminal COOH group after melt thermal stability test)
-(Terminal COOH group before the melt heat stability test)].

Example 1 49.2 parts of 1,4-butanediol and 28.1 of succinic acid were placed in a glass polymerization tube provided with a stirring blade, a pressure reducing port, and a nitrogen inlet.
And 46.2 parts of dimethyl terephthalate, and the atmosphere in the system was changed to a nitrogen atmosphere by nitrogen-vacuum substitution. Next, the temperature was raised to 185 ° C. while stirring the system, and the system was maintained for 30 minutes. Thereafter, the temperature was raised to 220 ° C. over 1 hour and 30 minutes, water generated by the reaction was distilled off, and an esterification reaction was performed. Here, 0.071 g of tetrabutyl titanate was used as a catalyst.
And 0.045 g of magnesium acetate tetrahydrate were dissolved in 1,4-butanediol and added to the system. Next, the temperature was raised to 260 ° C. over 1 hour, and simultaneously, the pressure was gradually reduced to 0.5 mmHg over 1 hour and 30 minutes. 2
The polymerization reaction was terminated 3 hours after the temperature reached 60 ° C.

The reduced viscosity (ηsp /
c) is 2.17 and the amount of terminal carboxyl groups is 3
It was 1.4 eq / ton. After heat treatment of the polyester at 260 ° C. for 30 minutes, the amount of terminal carboxyl groups is 44.3.
eq / ton and reduced viscosity (η _sp / c) was 2.05. The viscosity retention was 94.5% and the increase in terminal COOH groups (ΔCOOH) was 12.9 eq / ton. The polyester was treated at 250 ° C. for 15 minutes in a sample tube, and the generated gas was measured by gas chromatography. As a result, almost no tetrahydrofuran (THF) was recognized. This result indicates that almost no THF gas is generated during molding.

Comparative Example 1 Example 1 was repeated except that 0.071 g of tetrabutyl titanate was used as a catalyst and no magnesium acetate was used.
Polymerization was carried out in the same manner as described above. The viscosity (η _sp / c) of the obtained polyester was 1.61, and the amount of terminal carboxyl groups was 46.9 eq / ton. The polyester 2
The amount of terminal carboxyl groups after heat treatment at 60 ° C. for one hour is 9
4.7 eq / ton and viscosity (η _sp / c) of 0.9
It was 4. The viscosity retention rate is 58.4% and the terminal COOH
The group increase (ΔCOOH) was 47.8 eq / ton. When treated at 250 ° C. in the same manner as in Example 1, T
The generation of HF gas was large.

Example 2 In Example 1, adipic acid was replaced by 3 in place of succinic acid.
Except for using 4.7 parts, polymerization was carried out in the same manner as in Example 1 to obtain an aliphatic aromatic polyester. The reduced viscosity (η _sp / c) of the obtained polyester was 2.03,
The amount of terminal carboxyl groups was 35.4 eq / ton.
The amount of terminal carboxyl groups after heat treatment of the polyester at 260 ° C. for 30 minutes was 58.3 eq / ton, the terminal vinyl group was 6.3 eq / ton, and the reduced viscosity (η _sp / c)
Was 1.71. The viscosity retention was 84.2%, and the increase in terminal COOH groups (ΔCOOH) was 22.9 eq / ton. When the polyester was treated at 250 ° C. in the same manner as in Example 1, almost no THF gas was generated.

Comparative Example 2 Example 2 was repeated except that 0.071 g of tetrabutyl titanate was used as a catalyst and no magnesium acetate was used.
Polymerization was carried out in the same manner as described above. The reduced viscosity (η _sp / c) of the obtained polyester was 1.47, and the amount of terminal carboxyl groups was 40.7 eq / ton. The amount of terminal carboxyl groups after heat treatment of the polyester at 260 ° C. for 1 hour was 92.4 eq / ton, and the viscosity (η _sp /
c) was 0.85. The viscosity retention rate is 57.8%,
The increase in terminal COOH groups (ΔCOOH) is 51.7 eq /
Tons.

Example 3 49.2 parts of 1,4-butanediol and 28.1 parts of succinic acid were placed in a glass polymerization tube equipped with a stirring blade, a pressure reducing port, and a nitrogen inlet.
And 46.2 parts of dimethyl terephthalate, and the atmosphere in the system was changed to a nitrogen atmosphere by nitrogen-vacuum substitution. Next, the temperature was raised to 185 ° C. while stirring the system, and the system was maintained for 30 minutes. Thereafter, the temperature was raised to 220 ° C. over 1 hour and 30 minutes, water generated by the reaction was distilled off, and an esterification reaction was performed. Here, 0.071 g of tetrabutyl titanate was used as a catalyst.
And 0.045 g of magnesium acetate tetrahydrate were dissolved in 1,4-butanediol and added to the system. Next, the temperature was raised to 230 ° C. over 1 hour, and simultaneously, the pressure was gradually reduced to 0.5 mmHg over 1 hour and 30 minutes. 2
Four hours after the temperature reached 30 ° C., the polymerization reaction was terminated.

The reduced viscosity (η _sp /
c) is 2.21 and the amount of terminal carboxyl groups is 6.
It was 3 eq / ton. The polyester is heated at 260 ° C.
The amount of terminal carboxyl groups after heat treatment for 30 minutes at 24.3.
eq / ton and the viscosity (η _sp / c) was 2.02. The viscosity retention is 91.4% and the terminal COOH
The group increase (ΔCOOH) was 18.0 eq / ton. )

Comparative Example 3 Example 3 was repeated except that 0.071 g of tetrabutyl titanate was used as a catalyst and no magnesium acetate was used.
Polymerization was carried out in the same manner as described above. The viscosity (η _sp / c) of the obtained polyester was 1.69, and the amount of terminal carboxyl groups was 26.9 eq / ton. After heat treatment of the polyester at 260 ° C. for 1 hour, the amount of terminal carboxyl groups was 73.7 eq / ton, and the viscosity (η _sp / c) was 1.16. The viscosity retention was 68.6% and the terminal C
The increase in OOH groups (ΔCOOH) was 46.8 eq / ton.

Example 4 The procedure of Example 3 was repeated, except that a predetermined amount (34.7 parts) of adipic acid was used instead of succinic acid, to carry out polymerization to obtain an aliphatic aromatic polyester. The reduced viscosity (η _sp / c) of the obtained polyester was 2.03.

Comparative Example 4 Example 4 was repeated except that 0.071 g of tetrabutyl titanate was used as a catalyst and no magnesium acetate was used.
Polymerization was carried out in the same manner as described above. The reduced viscosity (η _sp / c) of the obtained polyester was 1.58.

Example 5 51.8 parts of 1,4-butanediol, 23.6 parts of succinic acid
, And polymerization was carried out in the same manner as in Example 1 except that 58.3 parts of dimethyl terephthalate was charged. The viscosity (η _sp / c) of the obtained polyester was 1.87. Example 6 51.8 parts of 1,4-butanediol, 35.4 succinic acid
, And polymerization was carried out in the same manner as in Example 1 except that 38.8 parts of dimethyl terephthalate was charged. The viscosity (η _sp / c) of the obtained polyester was 2.43.

[0041]

According to the method of the present invention, since the polymerization rate is high (melt polymerizability is high), the polymerization time can be shortened or added, and the productivity can be remarkably improved. In addition, the obtained aliphatic aromatic polyester is easily obtained as a high polymer because side reactions are suppressed during the reaction, and is excellent in biodegradability, but also suppresses side reactions during molding. Therefore, the main chain break is less likely to occur, and as a result, the mechanical properties etc. of the product are less likely to decrease,
Furthermore, since the generation of tetrahydrofuran is suppressed, low gas properties are maintained during molding.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takatoshi Seto 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation Yokohama Research Laboratory F-term (reference) 4J029 AA03 AB04 AC02 AD01 AD02 AE01 AE03 AE11 BA05 BA08 BD07A CA04 CA06 CB06A HB01 HB03A JA011 JA091 JA111 JA121 JA261 JB131 JB171 JF131 JF141 JF181 JF321 KB02 KB05 KE05

Claims (8)

[Claims] 1. A glycol component mainly comprising an aliphatic glycol and / or an alicyclic glycol, and a dicarboxylic acid mainly comprising an aliphatic dicarboxylic acid (a) and an aromatic dicarboxylic acid lower alkyl ester (b). A process for producing an aliphatic aromatic polyester, comprising melt-polymerizing an acid component in the presence of a titanium compound [A] and a metal compound of Group IIA of the periodic table as a polymerization catalyst. 2. Ratio (molar ratio) of aliphatic dicarboxylic acid (a) to aromatic dicarboxylic acid lower alkyl ester (b)
Satisfies the following expression: 2. The method for producing an aliphatic aromatic polyester according to claim 1, wherein 0.2 ≦ (a) / [(a) + (b)] ≦ 0.9 3. A ratio (molar ratio) of an aliphatic dicarboxylic acid (a) to an aromatic dicarboxylic acid lower alkyl ester (b).
Satisfies the following expression: 2. The method for producing an aliphatic aromatic polyester according to claim 1, wherein 0.3 ≦ (a) / [(a) + (b)] ≦ 0.7 4. The method according to claim 1, wherein the aliphatic glycol component is mainly 1,4-
3. The method for producing an aliphatic aromatic polyester according to claim 1, wherein the aliphatic aromatic polyester is butanediol, and the alicyclic glycol component is mainly 1,4-cyclohexanedimethanol. 5. The method according to claim 1, wherein the aliphatic dicarboxylic acid is mainly succinic acid and / or adipic acid, and the aromatic dicarboxylic acid lower alkyl ester is mainly terephthalic acid lower alkyl ester. A method for producing an aliphatic aromatic polyester according to any one of the preceding claims. 6. The method according to claim 1, wherein [B] the metal compound belonging to Group IIA of the periodic table is a magnesium compound.
The method for producing an aliphatic aromatic polyester according to any one of the above. 7. The use amount of the magnesium compound is as follows:
[A] The method for producing an aliphatic aromatic polyester according to any one of claims 1 to 6, wherein the molar ratio of magnesium to titanium of the titanium compound (equivalent ratio) is 0.1 to 10 times. . 8. The glycol component is mainly 1,4-butanediol, the aliphatic dicarboxylic acid is mainly succinic acid and / or adipic acid, and the lower alkyl ester of aromatic dicarboxylic acid is mainly dimethyl terephthalate. The method for producing an aliphatic aromatic polyester according to any one of claims 1 to 7, characterized in that: