JP3342570B2 - Method for producing polyethylene succinate - Google Patents

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 high-molecular-weight polyethylene succinate which prevents coloring, is decomposed by microorganisms in soil, and can be used as a molded article.

[0002]

2. Description of the Related Art Plastics used as synthetic fibers, films and other molded products can be supplied stably at low cost and in large quantities in addition to the advantages of being light and durable.
It has brought richness and convenience to our lives and built a modern society that can be called a plastic civilization. However, in recent years, there has been a demand for the development of a polymer material that can be decomposed in the natural environment in response to environmental problems on a global scale. And high expectations as a new type of functional material.

[0003] It is well known that aliphatic polyesters are biodegradable, and among them, poly-3-hydroxybutyric acid (PH
B) or synthetic polymer poly-ε-caprolactone (P
CL) and polyglycolic acid (PGA) are representative thereof.

[0004] Biopolyesters mainly composed of PHB are produced industrially because of their excellent environmental compatibility and physical properties. However, they are poor in productivity and are generally represented by polyethylene in view of cost. There is a limit to be able to substitute as a plastic for use (Fiber and Industry, vol. 47, p. 532 (1991)). For PCL, fibers,
Although a polymer with a high degree of polymerization that can be formed into a film is obtained, its melting point is less than 65 ° C and its heat resistance is poor, so it cannot be applied to a wide range of applications [Polym. Sci. Technol. 61 pages (1973)
reference〕. Furthermore, PGA and glycolide-lactide (9: 1) copolymers that have been put into practical use as biocompatible sutures are metabolically absorbed in vivo after undergoing abiotic hydrolysis. Since it is expensive and has poor water resistance, it is not suitable for use as ordinary plastic.

On the other hand, α, ω-aliphatic diols and α, ω-
Aliphatic polyesters produced by melt polycondensation with aliphatic dicarboxylic acids, such as polyethylene succinate (PES), polyethylene adipate (PEA) and polybutylene succinate (PBS) are long-known polymers that are inexpensive. It has been confirmed that it can be produced and is biodegraded by microorganisms in soil burial tests [Intert. Biodetetn. Bull., Vol. 11, 127].
(1975) and Polymer Science Technology (Polym. Sci. Technol.), Vol. 3, p. 61 (197)
However, these polymers have poor thermal stability,
Since a decomposition reaction occurs at the time of polycondensation, it is usually 2,000.
Only those having a molecular weight of about 6,000 (concentration of 0.5 g / deciliter using chloroform, reduced specific viscosity ηsp / c measured at 30 ° C. of 0.3 or less) are obtained, and processed into fibers or films. Was not enough. Among these, polyethylene succinate has a melting point of 100 ° C.
Above, and despite its excellent biodegradability being reported, the thermal stability during polymerization is poor, so using a normal method, it is possible to obtain a molecular weight sufficient for molding. No, for example, the literature (Int. Biodetetn.
Bull., Vol. 11, p. 127 (1975)], a commercially available low molecular weight polyethylene succinate is made to have a film forming ability by heating under reduced pressure, but the molecular weight is still at most about 20,000. However, sufficient performance could not be exhibited with this. Furthermore, polyethylene succinate having a molecular weight of up to 39,600 has been obtained by polycondensation of succinic acid and ethylene glycol by an operation such as removal of low molecular weight substances with methanol [Die Makromolekulare Chrysanthemum (Die Makromolekulare Ch.
emie), Vol. 140, p. 65 (1970)], however, this method has problems in that the operation is complicated and the yield of high molecular weight polyester is very poor.

In order to increase the molecular weight of these aliphatic polyesters, it has been reported to treat them with diisocyanates such as hexamethylene diisocyanate and toluene diisocyanate [Polym. J. ), Vol. 2, p. 387 (1971) and JP-A-4-189822].
Although it has the effect of increasing the molecular weight, the reaction process is usually two-stage and the process is complicated, and the obtained polyester has a slight decrease in crystallinity and melting point, and Since a urethane bond is contained therein, there has been a problem that biodegradability is somewhat inferior.

Further, it has been proposed to synthesize polyethylene succinate having a molecular weight of 10,000 or more by direct polycondensation using a titanium oxyacetylacetonate or an alkoxytitanium compound as a catalyst (Japanese Patent Application Laid-Open No. Hei 5 (1993) -205).
No. 70572). Furthermore, the polycondensation
A method for producing polyethylene succinate having a molecular weight of about 40,000 by performing the treatment under a high vacuum of 0.5 to 0.1 mmHg has been proposed (JP-A-5-310898).
Reference).

[0008]

However, in the method described in JP-A-5-70572, a small amount of a catalyst is used in order to prevent coloring, and thus the molecular weight is reduced to 1%.
There was a problem that it increased only to about 5,000. Furthermore, the method described in JP-A-5-310898 not only requires the use of a specific vacuum pump, but also has a problem that the melting point is lowered by about 10 ° C. due to a crosslinking reaction or the like.

The present invention has solved the above-mentioned problems of the conventional method, prevented coloring, and increased the molecular weight to such a degree that it could be used as a molded article without impairing the inherent properties of biodegradability. It is intended to provide a method for producing a high molecular weight polyethylene succinate.

[0010]

Means for Solving the Problems As a result of various studies to solve the above problems, the present inventors have produced succinic acid or succinic anhydride and ethylene glycol using a specific catalyst and a phosphorus compound. The inventors have found that polyethylene succinate can solve the above-mentioned problems, and have reached the present invention based on this finding.

That is, the present invention provides an oligomer obtained by reacting succinic acid or succinic anhydride with ethylene glycol, and then converting the obtained oligomer to one or more catalysts selected from titanium, germanium and antimony catalysts. And a polycondensation in the presence of a phosphorus compound.

Hereinafter, the present invention will be described in detail. First, in the present invention, it is necessary to react succinic acid or succinic anhydride with ethylene glycol to obtain an oligomer. At this time, the charging ratio of succinic acid or succinic anhydride to ethylene glycol is usually 1: 1 in molar ratio.
It is preferable to set it to 1-1: 2.2, and 1: 1.01-
1: 1.6 is more preferable, and 1: 1.05-1.5.
It is optimal to set 1: 1.5. In the present invention, succinic acid or succinic anhydride may be used alone, or a mixture thereof.

Further, the reaction conditions for producing an oligomer by transesterification are as follows.
The reaction is preferably carried out for 0 hour, at 150 to 220 ° C. for 2 to 5 hours, under atmospheric pressure, under an inert gas stream, particularly preferably under a nitrogen stream.

In the present invention, dicarboxylic acids such as oxalic acid, adipic acid, glutaric acid, suberic acid, sebacic acid, and the like, as long as the physical properties (eg, high melting point) of the aliphatic polyester obtained are not impaired. Dodecanoic acid and the like and diols such as 1,4-cyclohexanedimethanol, 1,4-butanediol, neopentyl glycol, diethylene glycol, propylene glycol and the like can be used in combination.

In the present invention, when synthesizing an oligomer by transesterification, a metal compound can be added as a catalyst. As the metal compound at that time, an organic metal compound, an organic acid salt, a metal complex, a metal alkoxide, a metal oxide, a metal hydroxide, a carbonate, a phosphate, a sulfate, a nitrate, a chloride and the like are used. , Among which acetate,
It is preferably used in the form of an acetylacetone metal complex metal oxide. The amount of the catalyst at this time was 0.02 to 100 parts by weight of the produced polyethylene succinate.
One part by weight is preferred.

Next, in the present invention, it is necessary to polycondense the oligomer obtained above with one or more catalysts selected from titanium, germanium and antimony catalysts in the presence of a phosphorus compound. is there.

In the present invention, as the polymerization catalyst for the polymerization after deliquoration, a titanium, germanium or antimony catalyst is used. These catalysts include metal alkoxides, metal acetylacetonates, metal oxides, metal complexes, It is used in the form of metal hydroxide, carbonate, sulfate, nitrate, acetate, chloride and the like. Examples of particularly preferred catalysts include tetra-n-butyl titanate, tetraisopropyl titanate, titanium oxyacetylacetonate, dibutoxydiacetacetoxytitanium, tetra-n-butoxygermanium, germanium oxide (IV), tributoxyantimony, Antimony trioxide, antimony acetate, etc., and one or more of these catalysts may be used. In addition, the amount of the catalyst used at that time is the polyethylene succinate 10
0.02 to 1 part by weight per 0 part by weight is preferable,
More preferably, it is used in the range of from 0.5 to 0.5 parts by weight.
When the amount of the catalyst is less than 0.02 parts by weight, the effect as a catalyst is weakened, and it becomes difficult to obtain a polymer having a target molecular weight. Even when the amount exceeds 1 part by weight, the effect is largely changed. On the contrary, the formed polymer is undesirably colored. These catalysts need only be present at the time of polycondensation, and may be added immediately before deglycolization or may be added before esterification.

In the present invention, the phosphorus compound used in the deglycolization and polycondensation includes phosphoric acid, polyphosphoric acid and the like.
Acid, metaphosphoric acid, bis (2,4-dibutylphenyl) pe
Antaerythritol diphosphate. These phosphorus compounds may be used alone or in combination of two or more. In addition, the amount of the phosphorus compound used at that time is determined based on the polyethylene succinate produced.
0.001 to 1 part by weight per 0 parts by weight is preferable,
0.01 to 0.5 part by weight is more preferable. The amount used is 0.
If the amount is less than 001 parts by weight, the effect of adding a phosphorus compound as a coloring inhibitor is weakened, and if it is 1 part by weight or more, the time required for polymerization is undesirably long. These phosphorus compounds need only be present at the time of polycondensation, and may be added immediately before deglycolization or may be added before esterification.

The conditions for the polycondensation are as follows:
It is preferably performed at 200 to 280 ° C for 1 to 10 hours under reduced pressure of 0.01 to 10 mmHg, and more preferably at 220 to 260 ° C for 1 to 5 hours under reduced pressure of 0.1 to 1 mmHg.

According to the method for producing polyethylene succinate of the present invention, gel filtration chromatography (GPC)
Polystyrene-equivalent number average molecular weight of 30,0
A white polymer having a color of not less than 00 and having no color is obtained.

The polyethylene succinate produced in this manner is not colored, is thermoplastic at a melting point of 100 ° C. or higher, and has moldability, so that it can be applied to various uses. Can be. For example,
As a biodegradable polymer, processed into films, fibers, sheets, etc., various bottles, shopping bags,
It can be used as a packaging material, a synthetic thread, a fishing line, a fishing net, a nonwoven fabric, an agricultural multi-film, and the like.

[0022]

The present invention will be specifically described below with reference to examples. In addition, each value was calculated | required as follows. (1) Number average molecular weight (Mn) in terms of polystyrene determined by GPC Using a GPC measuring device manufactured by Waters,
One each of Waters ultrastyragel with an average pore diameter of 10 ³ and 10 ⁴ mm, a total of two 7.8 mmφ × 30 cm connected
Measurements were made at 35 ° C. using a long column and using chloroform as eluent. In addition, polystyrene was used as a standard. (2) Reduced Specific Viscosity (ηsp / c) The molecular weight was measured by measuring the polymer solution viscosity at a concentration of 0.5 g / deciliter using an Ubbelohde viscometer. In addition, it measured at 30 degreeC using chloroform as a solvent. (3) Melting point The melting point was measured at a heating rate of 20 ° C./min using a thermal analyzer (DSC-7) manufactured by Perkin Elmer.

Example 1 47.2 g (0.4 mol) of succinic acid was placed in a three-necked flask equipped with a stirrer, a Wigrew fractionating tube, and a gas introducing tube.
32.3 g (0.52 mol) of ethylene glycol and 0.026 g (1.2 × 1) of magnesium acetate tetrahydrate
^0-4 ) was added and immersed in a hot water bath. 200 ℃
, And nitrogen was slowly flowed into the melt, and water and excess ethylene glycol were distilled off at a temperature of 200 ° C for 3 hours to obtain an oligomer.

Then, the oligomer was added with polyphosphoric acid 0.1%.
1 g and 0.14 g of tetra-n-butyl titanate (4.
0 × 10 ^-4 mol, resulting polyethylene succinate 1
(Equivalent to 0.24 parts by weight per 100 parts by weight), and keeping the temperature at 220 ° C., heat for 2 hours under reduced pressure of 0.5 mmHg and further for 3 hours at 240 ° C. under reduced pressure of 0.5 mmHg. As a result, a white polymer was obtained.

The ηsp / c of this polymer was 1.13 (concentration: 0.5 g / deciliter, 30 ° C., in chloroform), and the melting point was 103 ° C. The number average molecular weight (Mn) in terms of polystyrene determined by GPC was 56,
000.

Example 2 A white polymer was obtained in exactly the same manner as in Example 1 except that 0.05 g of phosphoric acid was used instead of 0.1 g of polyphosphoric acid. The ηsp / c of this polymer was 1.09 (concentration: 0.5 g / deciliter, at 30 ° C. in chloroform), and the melting point was 103 ° C. The number average molecular weight (Mn) in terms of polystyrene determined by GPC was 52,
000.

Example 3 47.2 g (0.4 mol) of succinic acid and 32.3 g (0.52 mol) of ethylene glycol were placed in a three-necked flask equipped with a stirrer, a Wiggrew fractionating tube and a gas introducing tube. Put and soak in hot water bath. The temperature of this hot water bath was raised to 200 ° C,
Nitrogen was slowly flowed into the melt, and water and excess ethylene glycol generated at a temperature of 200 ° C. for 3 hours were distilled off to obtain an oligomer.

Next, this oligomer was added to polyphosphoric acid 0.1%.
1 g and 0.15 g of tetra-n-butoxygermanium
(4.0 × 10 ⁻⁴ mol, corresponding to 0.26 parts by weight per 100 parts by weight of the resulting polyethylene succinate), keeping the temperature at 220 ° C. under a reduced pressure of 0.5 mmHg for 2 hours, By heating at 240 ° C. under a reduced pressure of 0.5 mmHg for 1 hour, a white polymer was obtained.

The ηsp / c of this polymer was 1.09 (concentration: 0.5 g / deciliter, 30 ° C., in chloroform), and the melting point was 104 ° C. The polystyrene equivalent number average molecular weight (Mn) determined by GPC is 53,
000.

Example 4 47.2 g (0.4 mol) of succinic acid and 32.3 g (0.52 mol) of ethylene glycol were placed in a three-necked flask equipped with a stirrer, a Wiggrew fractionating tube and a gas introducing tube. Put and soak in hot water bath. The temperature of this hot water bath was raised to 200 ° C,
Nitrogen was slowly flowed into the melt, and water and excess ethylene glycol generated at a temperature of 200 ° C. for 3 hours were distilled off to obtain an oligomer.

Then, the oligomer was added with polyphosphoric acid 0.1%.
1 g and 0.14 g of tributoxyantimony (4.0 × 1
0 ^-4 moles, equivalent to 0.24 parts by weight per 100 parts by weight of the resulting polyethylene succinate).
A white polymer was obtained by heating at 0 ° C. under a reduced pressure of 0.5 mmHg for 2 hours and further at 240 ° C. under a reduced pressure of 0.5 mmHg for 3 hours.

The ηsp / c of this polymer was 1.02 (concentration: 0.5 g / deciliter, 30 ° C., in chloroform), and the melting point was 102 ° C. The number average molecular weight (Mn) in terms of polystyrene determined by GPC is 50,
000.

Example 5 40.0 g (0.4 mol) of succinic anhydride and 32.3 g (0.52 mol) of ethylene glycol were placed in a three-necked flask equipped with a stirrer, a Wiggrew fractionating tube and a gas introducing tube.
And soaked in a hot water bath. The temperature of the water bath was raised to 200 ° C., nitrogen was slowly flowed into the melt, and water and excess ethylene glycol generated at 200 ° C. for 2 hours were distilled off to obtain oligomers.

Then, polyphosphoric acid was added to the oligomer in an amount of 0.
1 g and 0.15 g of tetra-n-butoxygermanium
(4.0 × 10 ⁻⁴ mol, corresponding to 0.26 parts by weight per 100 parts by weight of the produced polyethylene succinate), and the temperature was maintained at 220 ° C. for 1 hour under a reduced pressure of 0.5 mmHg. By heating at 240 ° C. under a reduced pressure of 0.5 mmHg for 3 hours, a white polymer was obtained.

The ηsp / c of this polymer was 1.07 (concentration: 0.5 g / deciliter, 30 ° C., in chloroform), and the melting point was 104 ° C. The number average molecular weight (Mn) in terms of polystyrene determined by GPC was 52,
000.

Example 6 A white polymer was obtained in the same manner as in Example 5, except that 0.05 g of phosphoric acid was used instead of 0.1 g of polyphosphoric acid. The ηsp / c of this polymer was 1.02 (concentration: 0.5 g / deciliter, 30 ° C, in chloroform), and the melting point was 103 ° C. The number average molecular weight (Mn) in terms of polystyrene determined by GPC is 50,
000.

Example 7 A white polymer was obtained in exactly the same manner as in Example 5 except that 0.1 g of metaphosphoric acid was used instead of 0.1 g of polyphosphoric acid. The ηsp / c of this polymer was 1.04 (concentration: 0.5 g / deciliter, at 30 ° C. in chloroform), and the melting point was 104 ° C. The number average molecular weight (Mn) in terms of polystyrene determined by GPC was 52,
000.

Example 8 A three-necked flask equipped with a stirrer, a Wigrew fractionating tube and a gas introducing tube was charged with 40.0 g (0.4 mol) of succinic anhydride and 32.3 g (0.52 mol) of ethylene glycol. , 0.026 g of magnesium acetate tetrahydrate (1.2
× 10 ^-4 ) and immersed in a hot water bath. This bath is 200
℃, slowly flow nitrogen into the melt, 200 ℃
The resulting water and excess ethylene glycol were distilled off at a temperature of 2 hours to obtain an oligomer.

Next, this oligomer was added with polyphosphoric acid 0.1%.
1 g and 0.14 g of tetra-n-butyl titanate (4.
0 × 10 ^-4 mol, resulting polyethylene succinate 1
(Corresponding to 0.24 parts by weight per 100 parts by weight), and keeping the temperature at 220 ° C., heat for 1 hour under a reduced pressure of 0.5 mmHg and further for 3 hours under a reduced pressure of 0.5 mmHg at 240 ° C. Thereby, a white polymer was obtained.

The ηsp / c of this polymer was 1.11 (concentration: 0.5 g / deciliter, 30 ° C., in chloroform), and the melting point was 103 ° C. The number average molecular weight (Mn) in terms of polystyrene determined by GPC is 55,
000.

Example 9 A three-necked flask equipped with a stirrer, a Wiggrew fractionating tube and a gas introducing tube was charged with 40.0 g (0.4 mol) of succinic anhydride and 32.3 g (0.52 mol) of ethylene glycol.
And soaked in a hot water bath. The temperature of the water bath was raised to 200 ° C., nitrogen was slowly flowed into the melt, and water and excess ethylene glycol generated at 200 ° C. for 2 hours were distilled off to obtain oligomers.

Next, bis (2,4-
Dibutylphenyl) pentaerythritol diphosphate 0.05 g and tributoxyantimony 0.14 g
(4.0 × 10 −4 mol, corresponding to 0.24 parts by weight per 100 parts by weight of the resulting polyethylene succinate), keeping the temperature at 220 ° C. under a reduced pressure of 0.5 mmHg for 1 hour, By heating at 240 ° C. under a reduced pressure of 0.5 mmHg for 3 hours, a white polymer was obtained.

The ηsp / c of this polymer was 1.05 (concentration: 0.5 g / deciliter, 30 ° C., in chloroform), and the melting point was 104 ° C. The number average molecular weight (Mn) in terms of polystyrene determined by GPC is 51,
000.

Comparative Example 1 A polymer was obtained in exactly the same manner as in Example 3 except that no polyphosphoric acid was added. This polymer is colored brown, ηsp / c is 0.70 (concentration 0.5 g / deciliter, 30 ° C., in chloroform), and melting point is 103 ° C.
Met. The number average molecular weight (Mn) in terms of polystyrene determined by GPC was 34,000.

[0045]

According to the present invention, it is possible to easily produce a high molecular weight polyethylene succinate which can be prevented from being colored and which can be used as a molded article.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (1)

(57) [Claims] 1. An oligomer is obtained by reacting succinic acid or succinic anhydride with ethylene glycol, and the obtained oligomer is combined with one or more catalysts selected from titanium, germanium and antimony catalysts, and phosphoric acid. , Poly
Phosphoric acid, metaphosphoric acid and bis (2,4-dibutylphenyl)
Le) selected from pentaerythritol diphosphate
A polycondensation in the presence of at least one phosphorus compound.