JP3342563B2 - Method for producing aliphatic polyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an aliphatic polyester. Further, the present invention relates to a method for producing a low-melting-point crystalline aliphatic polyester that can be melted at a low temperature of 80 ° C. or lower and used as a molded article.

[0002]

2. Description of the Related Art Polycaprolactone, for example, is a crystalline polyester having a low melting point. The polyester is softened at a low temperature of 50 to 80 ° C. and solidified at a room temperature.
It is used as a dental impression collecting material, a cast material, a wig molding material, and the like.

[0003] Instead of polycaprolactone, which is a crystalline polyester having a low melting point, a relatively low-cost fat mainly composed of glycols such as ethylene glycol, 1,4-butanediol and hexamethylene glycol and adipic acid. Various attempts have been made to provide aliphatic polyesters, but generally, aliphatic polyesters produced by melt polycondensation of α, ω-glycol and α, ω-dicarboxylic acid have poor thermal stability, and therefore have a high molecular weight. It has been extremely difficult to produce a polymer industrially stably.

That is, ethylene glycol, 1,4-
A low molecular weight compound obtained by esterifying one or more glycols selected from butanediol and hexamethylene glycol with adipic acid or a lower alkyl ester thereof at 150 to 230 ° C. in the presence of a polymerization catalyst such as tetrabutyl titanate When subjected to polycondensation at 200 to 250 ° C. under a high vacuum of 0.5 mmHg or less, the reduced specific viscosity of the obtained polymer η _sp / C (in chloroform, concentration 0.5 g / deciliter, measured at 30 ° C.) Did not exceed 0.5.

JP-A-62-85262 discloses that a metal salt of a saturated aliphatic monocarboxylic acid such as calcium stearate or magnesium stearate is used as a co-catalyst in combination with a polymerization catalyst such as tetra-n-butyl titanate. A method for producing butylene adipate is described. In this method, the reduced specific viscosity η _sp / C (in chloroform,
0.5 g / deciliter, measured at 30 ° C.)
Although a polymer close to the above was obtained, coloring was large and there was a practical problem.

In US Pat. No. 5,250,626, polybutylene adipate and polyhexa having a number average molecular weight of at least 10,000 or more are obtained by using tetra-n-butyl titanate and dibutyltin oxide as polymerization catalysts. Although methylene adipate and a method for producing the same are described, in this method, the polymer is easily colored during the production process, and the produced polymer is not practical.

[0007]

However, the conventional methods as described above have a problem that the molecular weight is hardly increased and coloring is easy. In general, the molecular weight of the aliphatic polyester is hardly increased, and as a cause that is easily colored, in such a reaction system, as compared with a polycondensation reaction which leads to an increase in the degree of polymerization, such as a thermal decomposition reaction which leads to a decrease in the degree of polymerization, etc. It is assumed that the decomposition reaction is dominant. That is, the reduced specific viscosity of the above-mentioned degree obtained by the conventional method (η _sp / C is 0.6 or less)
For example, the aliphatic polyester having only the tensile strength has a tensile strength of 2.0 kg / mm ² or less, and the strength is not practical.

[0008] The present invention is to solve the problems of the prior art, to provide a method for producing a high-molecular-weight, low-melting aliphatic polyester that can be used as a molded article while preventing coloring. It is intended for.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, by using a specific catalyst and a coloring inhibitor, 1,4-butanediol or hexamethylene The inventors have found that an aliphatic polyester having a high molecular weight and a low melting point can be produced from glycol and adipic acid, and the present invention has been achieved based on this finding.

That is, the present invention provides an oligomer obtained by reacting 1,4-butanediol or hexamethylene glycol with adipic acid, and the obtained oligomer is selected from titanium, antimony and germanium catalysts. A gist of the present invention is a method for producing an aliphatic polyester, which comprises performing polycondensation in the presence of at least one kind of catalyst and a specific phosphorus compound.

Hereinafter, the present invention will be described in detail. First, in the present invention, it is necessary to react 1,4-butanediol or hexamethylene glycol with adipic acid to obtain an oligomer. At this time, the charge ratio of glycol to adipic acid is usually 1: 1 to 1 in molar ratio.
1: 2.2 is preferred, and 1: 1.05-1: 1:
It is more preferred to be 1.6.

Further, the reaction conditions for producing an oligomer by performing esterification are as follows:
It is preferably carried out in the range of 10 hours, 150 to 220 ° C.
More preferably, the reaction is carried out at atmospheric pressure under a nitrogen stream for 2 to 5 hours.

In the present invention, glycols may be used as long as the physical properties of the resulting aliphatic polyester (eg, high crystallinity and thermal properties of melting at 80 ° C. or lower and solidifying at room temperature) are not impaired. For example, ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-cyclohexanediol, pentamethylene glycol, heptamethylene glycol and the like and dicarboxylic acids such as oxalic acid, succinic acid, malonic acid, glutaric acid , Pimelic acid, sebacic acid, and the like.

In the present invention, when an oligomer is produced by esterification, it is usually carried out without a catalyst, but a metal compound can be added as a catalyst. The metal at that time,
Organometallic compounds, organic acid salts, metal complexes, metal alkoxides, metal oxides, metal hydroxides, carbonates, phosphates, sulfates, nitrates, chloride, etc. It is preferably used in the form of an acetylacetone metal complex metal oxide.

Next, in the present invention, the oligomer obtained above is polycondensed in the presence of a catalyst and a phosphorus compound, and the catalyst is selected from titanium, antimony and germanium catalysts. It is necessary to use one or more catalysts. These are used in the form of metal alkoxide, metal oxide, metal complex, metal hydroxide, carbonate, sulfate, nitrate, chloride and the like. Examples of particularly preferred catalysts include tetra-n-butyl titanate, tetraisopropyl titanate, titanium oxyacetylacetonate, tributoxyantimony, antimony trioxide, tetra-n-butoxygermanium, germanium oxide, and the like. May be used alone or in combination of two or more. The amount of the catalyst used at that time is, per 100 parts by weight of the aliphatic polyester to be produced, 0.0
The amount is preferably 1 to 2 parts by weight, and more preferably 0.05 to 0.5 parts by weight. When the amount of the catalyst is less than 0.01 part by weight, the effect as a catalyst is weakened, and it is difficult to obtain a polymer having a target molecular weight. Are undesirably colored. Further, these catalysts may be added immediately before the glycolation or may be added before the esterification.

The phosphorus compound to be added together with the catalyst during the polycondensation includes bis (2,4-dibutylphenyl).
Le) Pentaerythritol diphosphate, polyphosphoric acid
Is mentioned. 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 preferably 0.001 to 1 part by weight, more preferably 0.01 to 0.5 part by weight, per 100 parts by weight of the aliphatic polyester to be produced. If the amount is less than 0.001 part by weight, the effect of adding the phosphorus compound as a coloring inhibitor becomes weak, and if it is 1 part by weight or more, the time required for polymerization becomes long, which is not preferable. Also,
These phosphorus compounds may be added immediately before the deglycolization or may be added before the esterification.

The reaction conditions for performing the polycondensation include:
It is preferably carried out under a reduced pressure of 0.01 to 10 mmHg at 180 to 260 ° C for 1 to 10 hours, and more preferably at a reduced pressure of 0.1 to 1 mmHg at 200 to 240 ° C for 1 to 6 hours.

The aliphatic polyester produced as described above has no thermal coloration, has the thermal property of melting at a temperature of 80 ° C. or less and solidifying at room temperature, and has a high molecular weight (η _sp / C of 1.
0 or more), and has high crystallinity and moldability, so that it can be used for applications such as dental impression collecting materials, cast materials, and wig molding materials.

In addition, with the recent increasing interest in the problem of treating plastic waste, aliphatic polyesters produced by melt polycondensation of α, ω-aliphatic glycols and α, ω-aliphatic dicarboxylic acids have been used in soil. Biodegradation by microorganisms has been reported [International Biodeterioration Bulletin (Int. Biodetet)
n. Bull.), vol. 11, p. 127 (1975) and Polymer Science Technology (Polym. Sci. Techno
l.), vol. 3, p. 61 (1973)], and great expectations are placed on environmentally compatible materials and new types of functional materials. Therefore, the aliphatic polyester obtained by the present invention is also processed as a biodegradable polymer into a film, fiber, or sheet, and is used for various bottles, shopping bags, packaging materials, synthetic yarn, fishing line, fishing net, nonwoven fabric, agricultural use It can be used as a multi-film or the like.

[0020]

The present invention will be specifically described below with reference to examples. In addition, each value was calculated | required as follows. (1) Reduction Specific Viscosity (η _sp / C) The solution viscosity of the polymer at a concentration of 0.5 g / deciliter was measured using an Ubbelohde viscometer to obtain a measure of the molecular weight. In addition, it measured at 30 degreeC using chloroform as a solvent. (2) Melting point Perkin Elmer's differential scanning calorimeter (DSC-
The measurement was performed at a heating rate of 20 ° C./min using 7). (3) Tensile strength and elongation at break Measured according to the method of tensile test ASTM D-882. (4) 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 having an average pore diameter of 10 ³ and 10 ⁴ A, each being connected to a total of 7.8 mmφ × 30 cm
Measurements were made at 35 ° C. using a long column and using tetrahydrofuran as eluent. In addition, polystyrene was used as a standard.

Example 1 In a three-necked flask equipped with a stirrer, a Wigrew fractionating tube and a gas introducing tube, 43.85 g (0.30 mol) of adipic acid and 35.18 g (0.1%) of 1,4-butanediol were added. 39
Mol) was immersed in an oil bath. The temperature of the oil bath was raised to 200 ° C., nitrogen was slowly flowed into the solution, and water and excess 1,4-butanediol generated at a temperature of 200 ° C. for 3 hours were distilled off to remove oligomers. Obtained.

Next, bis (2,4-dibutylphenyl) pentaerythritol diphosphate (GE speci
alty chemicals Ultra Knox (trademark) 62
6) 0.16 g and tetra-n-butyl titanate 0.1
1 g (3.0 × 10 ⁻⁴ mol) was added, the temperature was maintained at 210 ° C., and the pressure was reduced to 0.5 mmHg for 1 hour under a reduced pressure of 22 mm.
By heating at 0 ° C. under a reduced pressure of 0.5 mmHg for 3 hours, a white polymer having a number average molecular weight (Mn) of 53,000 and a weight average molecular weight (Mw) of 123,000 was obtained. Table 1 shows the physical properties of the obtained polymer.

Example 2 A white polymer was obtained in the same manner as in Example 1 except that 0.10 g of polyphosphoric acid was used instead of 0.16 g of bis (2,4-dibutylphenyl) pentaerythritol diphosphate. . Table 1 shows the physical properties of the obtained polymer.

Example 3 A white polymer was prepared in the same manner as in Example 1 except that 0.11 g (0.3 × 10 ⁻⁴ mol) of tributoxyantimony was used instead of 0.11 g of tetra-n-butyl titanate. Obtained. Table 1 shows the physical properties of the obtained polymer.

Example 4 Instead of 0.11 g of tetra-n-butyl titanate, 0.11 g of tetra-n-butoxygermanium (0.3 ×
^10-4 mol), and a white polymer was obtained in exactly the same manner as in Example 1. Table 1 shows the physical properties of the obtained polymer.

Example 5 A three-necked flask equipped with a stirrer, a Wigrew fractionating tube and a gas introducing tube was charged with 43.85 g (0.30 mol) of adipic acid and 39.06 g (0.30 g) of hexamethylene glycol.
3 mol) and immersed in an oil bath. 200 ° C
, And nitrogen was slowly flowed into the solution, and water and excess ethylene glycol generated at a temperature of 200 ° C for 3 hours were distilled off to obtain an oligomer.

Next, bis (2,4-dibutylphenyl) pentaerythritol diphosphate (GE speci
alty chemicals Ultra Knox (trademark) 62
6) 0.16 g and tetra-n-butyl titanate 0.1
1 g (3.0 × 10 ⁻⁴ mol) was added, the temperature was maintained at 210 ° C., and the pressure was reduced to 0.5 mmHg for 1 hour under a reduced pressure of 22 mm.
By heating at 0 ° C. under a reduced pressure of 0.5 mmHg for 3 hours, a white polymer having a number average molecular weight (Mn) of 46,000 and a weight average molecular weight (Mw) of 130,000 was obtained. Table 1 shows the physical properties of the obtained polymer.

Example 6 A white polymer was obtained in exactly the same manner as in Example 5 except that 0.10 g of polyphosphoric acid was used instead of 0.16 g of bis (2,4-dibutylphenyl) pentaerythritol diphosphate. . Table 1 shows the physical properties of the obtained polymer.

Example 7 A white polymer was prepared in the same manner as in Example 5 except that 0.11 g (0.3 × 10 ⁻⁴ mol) of tributoxyantimony was used instead of 0.11 g of tetra-n-butyl titanate. Obtained. Table 1 shows the physical properties of the obtained polymer.

Example 8 Instead of 0.11 g of tetra-n-butyl titanate, 0.11 g of tetra-n-butoxygermanium (0.3 ×
10 ^-4 mol) was used in the same manner as in Example 5 except that a white polymer was obtained. Table 1 shows the physical properties of the obtained polymer.

[0031]

[Table 1]

As shown in Table 1, when polycondensation is performed in the presence of a phosphorus compound with one or more catalysts selected from titanium, antimony and germanium-based catalysts, the white and practically usable strength is obtained. It can be seen that a polymer having a high molecular weight can be obtained.

Comparative Example 1 In a three-necked flask equipped with a stirrer, a Wigrew fractionating tube and a gas introducing tube, 43.85 g (0.30 mol) of adipic acid and 35.18 g (0.1%) of 1,4-butanediol were added. 39
Mol) was immersed in an oil bath. The temperature of the oil bath was raised to 200 ° C., nitrogen was slowly flowed into the solution, and water and excess 1,4-butanediol generated at a temperature of 200 ° C. for 3 hours were distilled off to remove oligomers. Obtained.

Then, 0.11 g (3.0 × 10 ^-4 mol) of tetra-n-butyl titanate was added, and the temperature was lowered to 21.
The polymer was obtained by heating at 0 ° C. under a reduced pressure of 0.5 mmHg for 1 hour and further at 220 ° C. under a reduced pressure of 0.5 mmHg for 3 hours to obtain a polymer. The polymer was colored brown. Table 2 shows the physical properties of the obtained polymer.

Comparative Example 2 Calcium stearate was added as a co-catalyst to 0.0
A polymer was obtained in the same manner as in Comparative Example 1 except that 55 g (3 × 10 ⁻⁴ mol / 1 mol of adipic acid) was added, but this polymer was also colored brown. Table 2 shows the physical properties of the obtained polymer.

Comparative Example 3 In place of 0.055 g of calcium stearate, 0.055 g of magnesium stearate (3 × 10 ⁻⁴ mol /
A polymer was obtained in the same manner as in Comparative Example 2 except that adipic acid (1 mol) was used, but this polymer was also colored brown. Table 2 shows the physical properties of the obtained polymer.

Comparative Example 4 Comparative Example 1 was repeated except that 39.06 g of hexamethylene glycol was used instead of 35.18 g of 1,4-butanediol.
A polymer was obtained in the same manner as described above, and this polymer was also colored brown. Table 2 shows the physical properties of the obtained polymer.

Comparative Example 5 A three-necked flask equipped with a stirrer, a Wigrew fractionating tube and a gas introducing tube was charged with 43.85 g (0.30 mol) of adipic acid and 27.36 g (0.4%) of 1,4-butanediol. 30
3 mol) and immersed in an oil bath. 200 ° C
, And nitrogen was slowly flowed into the solution, and water and excess 1,4-butanediol produced at a temperature of 200 ° C for 3 hours were distilled off to obtain an oligomer.

Then, 0.011 g (3.0 × 10 ⁻⁵ mol) of tetra-n-butyl titanate was added, and
The polymer was obtained by heating at 10 ° C. under a reduced pressure of 0.5 mmHg for 1 hour and further at 220 ° C. under a reduced pressure of 0.5 mmHg for 3 hours to obtain a polymer. The polymer was colored yellow.

Comparative Example 6 Polyhexamethylene adipate was obtained in the same manner as in Comparative Example 5 except that 35.86 g of hexamethylene glycol was used instead of 27.36 g of 1,4-butanediol. This polymer was also colored yellow. Was.

[0041]

[Table 2]

As shown in Table 2, if no phosphorus compound is added during polycondensation, the obtained polymer is colored,
In addition, it can be seen that it does not have the strength that can withstand practical use.

[0043]

According to the present invention, it is possible to inexpensively produce a high-molecular-weight, low-melting aliphatic polyester which can be prevented from being colored and which can be used as a molded article. Therefore, the aliphatic polyester obtained by the present invention can be used as a dental impression collecting material, a cast material, a wig molding material and the like.

──────────────────────────────────────────────────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 1,4-butanediol or hexamethylene glycol with adipic acid, and the obtained oligomer is at least one catalyst selected from titanium, antimony and germanium catalysts. And bis (2,4-dibutylphenyl) pentaerythris
A method for producing an aliphatic polyester, which comprises performing polycondensation in the presence of lithol diphosphate and / or polyphosphoric acid .