JP2003082081A - Method for producing polyester cyclic oligomer and method for producing polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a high purity polyester cyclic oligomer in a good efficiency, and obtain a polyester having a high molecular weight by a subsequently performed ring-opening polymerization. SOLUTION: This method for producing the polyester cyclic oligomer and polyester is performed in the presence of a mesoporous material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an efficient method for producing a polyester cyclic oligomer, and a method for producing a polyester using the same.

[0002]

2. Description of the Related Art Polyester has been widely used in various fields including fibers, films and bottles because of its excellent properties. Among them, polyalkylene terephthalate is preferably used because it is excellent in mechanical strength, chemical properties, dimensional stability and the like. Further, among them, for example, fibers for industrial materials are required to have high strength, and a method of improving the fiber strength by increasing the molecular weight of polyalkylene terephthalate has been proposed.

Generally, polyalkylene terephthalate is
It is produced from terephthalic acid or its ester-forming derivative and alkylene glycol. In the commercial process for producing high molecular weight polymers, the method of increasing the degree of polymerization by melt polymerization followed by solid phase polymerization is widely used. Has been. However, the method of increasing the degree of polymerization by solid phase polymerization has some unfavorable characteristics as described below.

For example, solid-state polymerization requires a large increase in equipment costs such as a drying process of polyester chips.
Further, since the retention time of chips is long, it is required to greatly improve the productivity.

For such a problem, for example, WO96 / 223
In JP 19, the polyethylene terephthalate prepolymer having a degree of polymerization of 5 to 35 in a molten state is cooled at 120 to 210 ° C. and crystallized at the same time as pelletization, or a pelletized non-polymer having a degree of polymerization of 5 to 35 is used. Amorphous polyethylene terephthalate prepolymer is heated to 120-210 ℃ rapidly to crystallize polyethylene terephthalate prepolymer
A method of performing solid-state polymerization at ˜240 ° C. has been proposed. By doing so, it is proposed to reduce the equipment cost by performing the solid-state polymerization by omitting the melt polycondensation step. However, although the equipment cost is reduced by omitting melt polycondensation, in order to increase the degree of polymerization of polyethylene terephthalate, a considerable amount of reaction time is required in the solid-state polymerization process. Is insufficient to improve sex.

Therefore, as a method for efficiently obtaining a polyester having a high degree of polymerization in a short time, a ring-opening polymerization reaction method using a polyester cyclic oligomer has attracted attention. For example, D.
J. Brunelle reported that a polymer with a high degree of polymerization can be obtained in an extremely short time by ring-opening polymerization of a polyester cyclic oligomer (Macromolecules, vol.31,
4782 (1998).), And it seemed that the above problem could be solved at first glance, but the following new problems have emerged.
That is, it was not possible to efficiently obtain a polyester cyclic oligomer which is a raw material for this ring-opening polymerization.
Regarding the method for producing a polyester cyclic oligomer, for example, there is a method in which a monomer acid chloride and a diol are subjected to a cyclization reaction in the presence of an amine catalyst. This is because the size of the polyester cyclic oligomer is large, that is, the distribution of the degree of polymerization is large. It was not possible to obtain only the polyester cyclic oligomer of. Therefore, a separate purification step is required before ring-opening polymerization, and if purification is not performed,
There are problems that the degree of polymerization cannot be made sufficiently high, or that the amount of dialkylene glycol-based byproducts is increased and the molecular weight distribution is widened due to unreacted oligomers.

Therefore, an efficient method for producing a highly pure polyester cyclic oligomer has been desired.

[0008]

DISCLOSURE OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks in the synthesis of polyester cyclic oligomers, to efficiently produce a polyester cyclic oligomer having high purity, and to provide a highly polymerized polyester using the same. It is intended to provide an efficient manufacturing method.

[0009]

The above-mentioned object of the present invention is achieved by a method for producing a polyester cyclic oligomer, characterized in that a mesoporous substance is present.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Specific examples of the dicarboxylic acid component used in the esterification reaction of the present invention include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, aromatic dicarboxylic acids such as 4,4′-diphenyldicarboxylic acid, and adipine. acid,
Aliphatic dicarboxylic acids such as sebacic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and the like can be mentioned. Examples of the diol component include ethylene glycol, propanediol, butanediol, neopentyl glycol, hexamethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, cyclohexanedimethanol and the like.

Specific examples of the polyester obtained in the present invention include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate and polyethylene-1,2. -Bis (2-chlorophenoxy) ethane-4,4'-
Dicarboxylate etc. are mentioned. Of these, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, or a polyester copolymer mainly composed of polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate, which are widely used, are preferable.

The polyester obtained in the present invention is a fiber,
There is no particular limitation as long as it can be used as a molded product such as a film or a bottle.

Further, these polyesters include dicarboxylic acids such as adipic acid, isophthalic acid, sebacic acid, phthalic acid, 4,4'-diphenyldicarboxylic acid and their ester-forming derivatives, polyethylene glycol and diethylene glycol as copolymerization components. , Hexamethylene glycol, neopentyl glycol, polypropylene glycol and other dioxy compounds, p- (β-oxyethoxy)
An oxycarboxylic acid such as benzoic acid or lactic acid and an ester-forming derivative thereof may be copolymerized.

The mesoporous substance referred to in the present invention is, for example, mesoporous silica having an average pore size of nm order and a uniform pore size, and a peak is recognized on the low angle side in X-ray diffraction. is there. Mesoporous silica is different from conventional silica such as amorphous silica in that it has a uniform pore size. Independent by Mobil (J.Am.Chem.Soc., Vol.114,10834 (1992).) In 1992 and Toyota Nakaken (J.Chem.Soc., Chem.Commun.680 (1993).) In 1993. The typical examples are the novel silicas reported in, and MCM-41, FSM-16, etc. having a uniform honeycomb structure (Fig. 1) are typical examples. The mesoporous substance referred to in the present invention is not limited only to mesoporous silica, and even a mesoporous silica derivative containing a part of a different metal such as aluminum or titanium or an organic material, a metal oxide such as aluminum or titanium, or a derivative thereof, It may be a composite of.

In the present invention, it is important to synthesize a polyester cyclic oligomer in the presence of a mesoporous substance. At this time, if necessary, a catalyst may be supported on the mesoporous substance, or a substance having catalytic ability may be added to the skeleton of the mesoporous substance. Is preferably incorporated into As a method for supporting the catalyst on the mesoporous substance, for example, a method utilizing sublimation or a method utilizing a solution can be used. As a method of incorporating the catalyst into the skeleton of the mesoporous substance, for example, a method of mixing metal ions having catalytic ability with the raw material of the mesoporous substance can be used. In particular, titanium ion can be both an esterification catalyst and a polymerization catalyst, and therefore it is preferable to support it on a mesoporous substance or to incorporate it in the skeleton.

The pore size of the mesoporous substance is preferably equal to or larger than the size of the targeted polyester cyclic oligomer. As a result, the polyester cyclic oligomer having a specific size is stabilized in the pores, and as a result, the polyester cyclic oligomer having the specific size can be selectively synthesized. Here, the pore size can be represented by the average diameter of the pores in the state of supporting or incorporating the catalyst, and the polyester cyclic oligomer size can be represented by the major axis of the molecule. For example, a cyclic trimer of polyethylene terephthalate (PET), which is a general-purpose polyester, has a cyclic oligomer size of about 1 nm, so the pore size is preferably 1 nm or more. In addition, if the pore size is too large relative to the cyclic oligomer size, the stabilizing effect decreases, so the pore size is 10 times the cyclic oligomer size.
It is preferably not more than double. In this respect, zeolite, which is also a porous substance, has a fine pore size even before supporting a catalyst.
Since it is less than 1 nm, it is not suitable for producing a polyester cyclic oligomer.

Further, in the mesoporous material, since the pore size is extremely uniform, almost all the pores can contribute to the stabilization of the polyester cyclic oligomer.
In this respect, conventional silica such as amorphous silica, which is also a porous substance, has a too large pore size distribution and is not suitable for producing a polyester cyclic oligomer.

In the present invention, the mesoporous substance can be used as a powder, but can also be used as a film or coated on a substrate to facilitate separation from the product.

In the present invention, the method for producing the polyester cyclic oligomer is not particularly limited as long as the mesoporous substance is present. For example, a polyester cyclic oligomer can be produced in the presence of a mesoporous substance carrying an acid catalyst and a diol which are monomers as an amine catalyst.
At this time, as the amine catalyst, for example, 1,4-diazobicyclo [2.2.2] octane (DABCO) or triethylamine can be used.

It is also possible to produce a polyester cyclic oligomer in the presence of a mesoporous substance carrying a catalyst of a polyester linear oligomer synthesized in advance or a mesoporous substance having a metal ion having a catalytic ability in its skeleton. Examples of the catalyst include titanium catalysts such as titanium tetrabutoxide (Ti (BuO) ₄ , TBT) and titanium tetraisopropoxide (Ti (i-PrO) ₄ , TPT), monobutylhydroxytin oxide (MBO) and dibutyltin. Tin catalysts such as oxide (DBO) can be used. Further, these catalysts may contain a polydentate ligand. Titanium ions as metal ions having catalytic ability,
Aluminum ions, tin ions and the like can be used.

The catalyst amount is 0.0001 to 2 in terms of weight of metal ion based on the polyester cyclic oligomer obtained.
It can be wt%.

According to the production method of the present invention, the yield of the polyester cyclic oligomer is high, the distribution of the cyclic oligomer size, that is, the distribution of the degree of polymerization is narrow, and the purity of the aimed cyclic oligomer is higher than that of the conventional method. Have. Therefore, it can be preferably used for ring-opening polymerization thereof. The distribution of cyclic oligomer size can be determined, for example, by HPLC or
It can be evaluated using GPC. Further, by using the method of the present invention, it is possible to obtain a substance having a purity of 90% or more without substantially purifying it.

The method for ring-opening polymerization of the polyester cyclic oligomer obtained by the production method of the invention may be any known method without any limitation. For example, ring-opening polymerization may be carried out with a polyester cyclic oligomer alone, or polymerization may be carried out by mixing with a thermoplastic polymer in a molten state in order to enhance the solubility of the polyester cyclic oligomer. As the thermoplastic polymer, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinylidene chloride, fluororesin, which are addition polymerization systems,
There are polycondensation-type polyamides such as polymethylmethacrylate, polyesters, polycarbonates, polyphenylene oxides and the like, polyaddition-type polyurethanes and the like, ring-opening polymerization-type polyacetals and the like, and among these, polyester is preferable. Of these, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, or polyester copolymers mainly composed of polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate, which are generally used, are preferable.

Examples of the ring-opening polymerization catalyst include, for example, US Pat. Nos. 5,039,783, 5,214,158 and 5,231,161.
Various organotin compounds and titanate esters described in Japanese Patent Publication No. 1993-257 may be used as a catalyst for cyclic polyester oligomers, and di- (1-butyl) -2 is proposed in JP-A-8-253573. , 2-Dimethylpropane-1,3-
Dioxytitanate, bis (2,2-dimethyl-1,3-propylene) titanate or 1- (1-butoxy) -4-methyl-2,
Cyclic titanium catalysts such as 6,7-trioxa-1-titanabicyclo [2.2.2] octane may be used as catalysts for cyclic polyester oligomers. Also, Macromolecules, vol.33,
The antimony compound and the bismuth compound described in 3594 (2000) may be used and are not particularly limited.

The addition amount of the ring-opening polymerization catalyst can be 0.0001% by weight to 1% by weight in terms of the weight of metal ion with respect to the obtained polymer.

Further, when the thermoplastic polymer in a molten state is a polymer passed through a prepolymerization tank or a final polymerization tank of a continuous polymerization process, liquid transfer of a reactant between the polymerization tank and the ring-opening polymerization reaction tank A method is preferred in which a static mixing device is installed in the pipe and the polyester cyclic oligomer is supplied immediately before the device through a branch pipe. Further, the chipped thermoplastic polymer or the existing chipped thermoplastic polymer and the polyester cyclic oligomer may be melt-mixed by an extruder via the final polymerization tank in the continuous polymerization process. Here, the extruder is not particularly limited, but as a conventionally known extruder, a single-screw kneader, 2
Examples thereof include a shaft type kneader and a kneader with a vent.

In the present invention, a conventionally known phosphorus compound or cobalt compound may be added to the finally obtained polyester at an arbitrary time for the purpose of improving heat resistance and color tone. Further, in the present invention, known compounds such as inorganic particles for matting, antioxidants, heat insulating materials, antistatic agents, and ultraviolet absorbers may be added and contained as necessary.

[0028]

EXAMPLES Reference Example 1 (Synthesis of MPS-1) 50 g of dried kanemite crystals was dried in an amount of 0.1 ml of 0.1 M n-hexadecyltrimethylammonium chloride aqueous solution 1000 ml.
And was stirred at 70 ° C. for 3 hours. Initial heating pH is 12.
Was 3. After that, 2N hydrochloric acid was added to lower the pH to 8.5.
After stirring for 3 hours, the mixture was allowed to cool to room temperature. This is filtered, the solid product is dispersed in 1000 ml of deionized water,
It was filtered again. This dispersion stirring / filtration was performed 5 times, and the solid was dried at 60 ° C. By calcining this at 500 ° C. for 6 hours, mesoporous silica was obtained. This is called MPS-1. A peak was observed on the low angle side of this MPS-1 by X-ray diffraction, and it was confirmed that it has a regular periodic structure and uniform pores are formed. Also, the average pore diameter obtained from the nitrogen gas adsorption method is 2.6 nm, the specific surface area is 1100 m ² / g,
The average aggregate diameter was 0.5 μm.

Reference Example 2 (Synthesis of MPS-2) n-octadecyltrimethylammonium chloride 3.
A mixture of 13 g, ion-exchanged water 300 g, and 6 N NaOH aqueous solution 15 g
With stirring at 0 ° C., 20.3 g of 1,2-bis (trimethoxysilyl) ethane was added, and the mixture was stirred for 3 hours. The mixture was left standing at room temperature for 14 hours, then stirred for further 13 hours, further left at room temperature for 14 hours, and further stirred for 7 hours. Then, the solid matter was filtered, washed with ion-exchanged water, and then air-dried. After removing n-octadecyltrimethylammonium used as a template with an ethanol / hydrochloric acid mixed solvent, this was washed with ion-exchanged water 5 times and dried under reduced pressure at 150 ° C for 24 hours to obtain an organic group-containing mesoporous silica. The derivative was obtained. This is called MPS-2. A peak was observed on the low-angle side of this MPS-2 by X-ray diffraction, and it was confirmed that it has a regular periodic structure and uniform pores are formed. Further, the average pore diameter obtained from the nitrogen gas adsorption method is 3.8 nm, the specific surface area is 1450 m ² / g,
The average aggregate diameter was 0.5 μm.

Reference Example 3 (Synthesis of MPS-3) Tetraethyl orthosilicate (TEOS) and tetraethyl orthotitanate (TEOT) were mixed at a molar ratio of 1: 0.08 to prepare 1
After stirring for 5 minutes, decylamine with a molar ratio of 0.68 to TEOS was added. The mixed solution was stirred for 10 minutes, and then a 0.5N aqueous hydrochloric acid solution was added, and the resulting suspension was further stirred for 24 hours.
This was centrifuged and the solid content was collected, and then dried at 50 ° C. for 2 days. Then, it was calcined at 500 ° C. for 2 hours to obtain mesoporous silica containing 5.1 mol% of Ti. This is called MPS-3. A peak was observed on the low angle side of this MPS-3 by X-ray diffraction, and it was confirmed that it had a regular periodic structure and uniform pores were formed. Further, the average pore diameter determined by the nitrogen gas adsorption method was 3.1 nm, the specific surface area was 1050 m ² / g, and the average aggregate diameter was 0.6 μm.

Hereinafter, the present invention will be described in more detail with reference to examples. The physical property values in the examples were measured by the methods described below.

A. The yield and purity of the polyester cyclic oligomer was subjected to high performance liquid chromatography (HPLC),
From the peak area, the yield of the polyester cyclic oligomer and the purity of the desired polyester cyclic oligomer in the entire polyester cyclic oligomer were calculated. A calibration curve was prepared in advance for the amount of each oligomer and the peak area corresponding to it.

B. Intrinsic viscosity of polyester [η] It was measured at 25 ° C. using orthochlorophenol as a solvent.

Examples 1, 2 MPS-1 and MPS-2 were immersed in a dichloromethane solution of 1,4-diazabicyclo [2.2.2] octane (DABCO), the solvent was removed, and 20% by weight of DABCO was loaded. The obtained mesoporous silica was obtained.

The mixture was stirred for 30 minutes in dichloromethane at 0 ° C. in the presence of MPS-1 or MPS-2 carrying 20% by weight of DABCO containing terephthalic acid dichloride and ethylene glycol. At this time, the concentration of terephthaloyl chloride and ethylene glycol was 0.1M, and the amount of mesoporous silica added was such that the supported DABCO concentration was 0.005M. Then, after neutralization, removal of dichloromethane and washing with water, the yield of PET cyclic oligomer,
When the purity of the cyclic trimer was examined, a high-purity PET cyclic oligomer was obtained in high yield.

Examples 3 and 4 MPS-1 was immersed in a solution of tetraisopropyl titanate (Ti (i-PrO) ₄ , TPT) in isopropanol, the solvent was removed, and mesoporous silica carrying 20% by weight of TPT was obtained. Obtained.

Terephthalic acid was added to ethylene glycol, and the esterification reaction was carried out according to a conventional method. to this,
TPT-supporting MPS-1 or MPS-3 was added to terephthalic acid so that the titanium atom content was 0.3 mol% to obtain a PET cyclic oligomer. At this time, α-methylnaphthalene was used as the solvent. After completion of the cyclization reaction, the solvent was removed and the yield of PET cyclic oligomer and the purity of the cyclic trimer were examined.
A PET cyclic oligomer was obtained.

Comparative Example 1 DABCO was prepared by adding terephthalic acid dichloride and ethylene glycol.
Stir in dichloromethane in the presence of 0 ° C. for 30 minutes.
At this time, the concentration of terephthalic acid dichloride and ethylene glycol was adjusted to 0.1M, and the DABCO concentration was adjusted to 0.005M.
After neutralization, removal of dichloromethane and washing with water, the yield of PET cyclic oligomer and the purity of cyclic trimer were examined.
Both the yield of the cyclic oligomer and the purity of the cyclic trimer were inferior.

[0039]

[Table 1] Examples 5 and 6 PET chips separately produced from the PET cyclic oligomers obtained in Examples 1 and 2 had a weight mixing ratio of oligomer / polymer = 8.
The mixture was mixed at 0/20, and 0.08% by weight of monobutylhydroxytin oxide as a ring-opening polymerization catalyst was added to the PET polymer, and the mixture was supplied to a twin-screw extruder. The average residence time of this twin-screw extruder was 15 minutes, but ring-opening polymerization rapidly proceeded during the retention, and a PET polymer was obtained. The intrinsic viscosity of this was 1.45 and 1.34, and the PET cyclic trimer of the present invention was excellent in ring-opening polymerization reactivity even without a purification step.

Examples 7 and 8 PET chips separately prepared from the PET cyclic oligomers obtained in Examples 3 and 4 had a weight mixing ratio of oligomer / polymer = 8.
The mixture was mixed to 0/20 and fed to the twin-screw extruder used in Example 5. At this time, the mesoporous silica used in the synthesis of the PET cyclic oligomer functions as it is as a ring-opening polymerization catalyst, and the ring-opening polymerization rapidly progresses during the retention.
A T-polymer was obtained. It has an intrinsic viscosity of 1.40 and
It was 1.38, and the PET cyclic trimer of the present invention had excellent ring-opening polymerization reactivity even without a purification step.

COMPARATIVE EXAMPLE 2 The PET cyclic oligomer obtained in Comparative Example 1 was separately prepared with P.
ET chip weight mixing ratio is oligomer / polymer = 80/20
Then, TPT was added as a ring-opening polymerization catalyst, and the mixture was fed to the twin-screw extruder used in Example 5. The intrinsic viscosity of the obtained PET polymer was as low as 0.65. This is because the PET cyclic trimer of Comparative Example 1 has low purity.

[0042]

[Table 2] Examples 9 and 10 Examples in which the synthesis of the polyester cyclic oligomer and the ring-opening polymerization are continuous processes are shown below.

A terephthalic acid and ethylene glycol were preliminarily stirred and prepared in a predetermined molar ratio in a continuous polymerization apparatus mainly composed of three reaction tanks of a first esterification reaction tank, a second esterification reaction tank and a polycondensation reaction tank. 2 slurries
It was supplied to the first esterification reaction tank at a supply rate of 3.8 parts by weight / hour. Average residence time in the first esterification reaction tank is 3 hours 5
0 minutes, reaction temperature 250 ℃, reaction pressure 1.013 × 10 ⁵ Pa,
The average degree of polymerization of the obtained reaction product was 3.0. The step of producing this linear polyester oligomer is referred to as step 1.

This reaction product was continuously withdrawn and fed to a reaction tank for synthesizing a cyclic oligomer. In this reaction tank, α-methylnaphthalene was used as a solvent, and TPT-supported MPS-1 or MPS-3 prepared in Example 3 was used as a catalyst at 0.2 mol% with respect to terephthalic acid. The obtained reaction product is sent to a solvent removal tank to remove α-methylnaphthalene, then sent to a solid deposition tank, and hexane is added to precipitate the reaction product contained in the solvent. It was The obtained mixture was separated from hexane by passing through a centrifugal separator / fluidized bed drier to obtain a PET cyclic oligomer. The step of producing this PET cyclic oligomer is referred to as step 2.

Further, the reaction product was continuously withdrawn,
This was mixed with separately produced PET chips, and the mixture was supplied to the twin-screw extruder used in Example 5. At this time, the mesoporous silica used in the synthesis of the PET cyclic oligomer functions as it is as a ring-opening polymerization catalyst, and the ring-opening polymerization rapidly progresses during the retention to obtain a PET polymer. This intrinsic viscosity is 1.4
It was 2, 1, 38. The step of producing polyester by this ring-opening polymerization is referred to as step 3.

Example 11 Example 9 was repeated except that butylene glycol and terephthalic acid were used as starting materials and the conditions were changed as shown in Table 3.
A polymer was produced in the same manner as in. The intrinsic viscosity of the obtained polybutylene terephthalate (PBT) polymer was 1.85, and it was possible to produce the polymer in an economically advantageous time.

Example 12 Example 9 was repeated except that propylene glycol and terephthalic acid were used as starting materials and the conditions were changed as shown in Table 3.
The polymer was polymerized in the same manner as in. The intrinsic viscosity of the obtained polytrimethylene terephthalate (PTT) polymer is 1.9.
It was 6, and it was possible to produce the polymer in an economically excellent time.

[0048]

[Table 3]

[0049]

EFFECT OF THE INVENTION Since the method for producing a polyester cyclic oligomer of the present invention provides a cyclic oligomer having a high degree of purity, it is possible to efficiently obtain a polyester having a high degree of polymerization by the ring-opening polymerization carried out subsequently.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing typical cultivation of mesoporous silica.

Claims (4)

[Claims] 1. A method for producing a polyester cyclic oligomer, which comprises the presence of a mesoporous substance. 2. The method for producing a polyester cyclic oligomer according to claim 1, wherein a catalyst is supported on the mesoporous substance. 3. The method for producing a polyester cyclic oligomer according to claim 1, wherein a substance having a catalytic ability is incorporated in the skeleton of the mesoporous substance. 4. A method for producing a polyester, which comprises subjecting the polyester cyclic oligomer obtained by the method according to any one of claims 1 to 3 to ring-opening polymerization.