JP2021109886A - Polyester resin production method - Google Patents

Abstract

To provide a high-quality polyester resin which prevents a foreign matter generated when a catalyst solution containing an organic titanium compound is measured and added to a reaction tank, is reduced in an amount of foreign matters in a polymer, is excellent in mechanical strength and color tone, and can be suitably used as a molding, a film, a monofilament and fibers.SOLUTION: A polyester resin production method is provided in which polyester resin is produced through an esterification reaction or transesterification reaction and a polycondensation reaction of a dicarboxylic acid or its ester formative derivative and diol or its ester formative derivative. In the method, a catalyst solution including an organic titanium compound is added to a reaction tank using an internal nozzle in at least one reaction selected from the esterification reaction, the transesterification reaction and the polycondensation reaction. In the inner nozzle, on a projection plane from the side of the nozzle tip, a cut surface of a nozzle tip is horizontal, and an angle (nozzle tip angle) formed by the cut surface of the nozzle tip and the upper side face of the nozzle is 40° to 50°.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a polyester resin.

Polybutylene terephthalate resin, which is a typical engineering plastic among thermoplastic polyester resins, is excellent in ease of molding, mechanical properties, heat resistance, chemical resistance, and other physical and chemical properties. Therefore, it is widely used in automobile parts, electrical / electronic parts, precision machine parts, etc.

Polybutylene terephthalate copolymer, which has polybutylene terephthalate as a hard segment and polyols as a soft segment, is a new elastomer that replaces conventional natural rubber and synthetic rubber, and is used for conventional thermoplastics such as injection molding and extrusion molding. It is widely used as a flexible and elastic material because it can be molded economically by a molding method and has many features such as excellent rubber elasticity, heat resistance, and chemical resistance.

When polyester resin is used for molded products, the color tone and heat resistance of the polyester resin affect the molding processability and the appearance, quality, and performance of the product. The presence of foreign matter in the polyester resin significantly impairs the appearance of the molded product and at the same time causes a strength defect of the molded product, which causes deterioration over time.

In the production of polyester resin, the direct polymerization method is a useful method because a polymer having stable quality can be obtained. It is well known that an organic titanium compound is used as a reaction catalyst in the production method. However, the organic titanium compound easily absorbs moisture, which causes a problem that the organic titanium compound hydrolyzes and significantly reduces the catalytic activity. Further, when the organic titanium compound is adjusted as a catalyst, it may be insolubilized and become cloudy depending on the adjustment conditions, and the charging line is blocked and the charging accuracy is deteriorated. Further, when the insolubilized and clouded foreign matter is supplied into the reaction system, it becomes a foreign matter in the polymer and causes an increase in haze (an index indicating turbidity of the molten polymer). As a result, the physical properties are finally deteriorated, such as a decrease in tensile breaking strength when the molded product is formed and an increase in surface foreign substances when the film is formed.

In Patent Document 1, the content of the diol compound in the organic titanium compound added to the esterification reaction tank is set to 5% by weight or less. A method of continuously adding to the diol refluxed from the bottom is described.

Patent Document 2 describes a method for heating and dissolving a hindered phenol-based compound in a solution prepared by adjusting an organic titanium compound with 1,4-butanediol for the purpose of stabilizing a catalytic solution containing the organic titanium compound. There is.

Patent Document 3 proposes a method of adding an organic titanium compound by heating a catalyst solution prepared by adjusting 2-hydroxymethylpyridine with diol to 150 ° C. in order to obtain a polyester resin having excellent color tone and few foreign substances. ..

Patent Document 4 proposes to set the pH of the catalyst solution of the titanium compound to 3.5 or less or 10.5 or more in order to obtain a catalyst solution for producing a polyester resin having excellent long-term storage stability.

In Patent Document 5, when a raw material slurry composed of a dicarboxylic acid and a diol is supplied to a reaction vessel, the length of a nozzle to be inserted into the reaction vessel is changed according to the liquid level of the reaction vessel, and the line of the slurry to be supplied is changed. Proposals have been made for polyesters having excellent quality with less foreign matter by preventing the slurry from coming into contact with the inner wall of the reaction vessel by specifying the speed.

JP-A-2010-83948 Japanese Unexamined Patent Publication No. 3-153731 Japanese Unexamined Patent Publication No. 2013-136730 Japanese Unexamined Patent Publication No. 2012-255144 Japanese Unexamined Patent Publication No. 2013-213194

However, in the method described in Patent Document 1, since the measurement of the organic titanium compound and the measures against deactivation at the time of adjusting with the diol are not taken into consideration, there is a problem that the organic titanium compound is insolubilized.

The catalyst prepared by the method described in Patent Document 2 causes decomposition and generation of foreign matter when the hindered phenolic compound itself is heat-dissolved and stored. Further, before adjusting the organic titanium compound by heating and dissolving it, when the organic titanium compound is weighed into the catalyst mixing tank used in the batch type reactor, the organic titanium compound having a high viscosity and a high reaction rate with water is used. It adheres to the inner wall of the catalyst mixing tank, reacts with moisture in the atmosphere, and gradually insolubilizes to become a cloudy foreign substance. When this foreign matter falls into the reaction system, there is a problem that the clogging of the filter in the process is increased, which causes equipment trouble and quality trouble, and the foreign matter in the polymer is increased.

In Patent Document 3, since pyridine is added as the third component, the polymer itself may become a foreign substance or the color tone of the polymer may change. Further, when adjusting the catalyst solution, when measuring the organic titanium compound having high viscosity and extremely high reaction rate with water, the organic titanium compound adheres to the inner wall of the adjustment tank of the catalyst solution, and water in the atmosphere. There is a problem that the organic titanium compound is insolubilized and a cloudy foreign substance is generated by gradually reacting with the above, but a method for reducing the foreign substance is not disclosed.

In Patent Document 4, since a strong acid such as hydrochloric acid is added to adjust the pH, the obtained polymer has a problem in color tone. Further, as in Patent Documents 1, 2, and 3, when preparing the catalyst solution, it is not considered to prevent the highly active titanium compound from adhering to the inner wall or the like and becoming a foreign substance during weighing. Therefore, there is a problem that the organic titanium compound is insolubilized.

Although Patent Document 5 mentions the suppression of foreign substances generated when the slurry is supplied, it does not disclose the generation of foreign substances during weighing when the organic titanium compound is used and the effect of reducing foreign substances in the obtained polyester resin. ..

When a catalyst solution containing an organic titanium compound, which is used for the purpose of productivity, reaction efficiency, and quality stability, is quantitatively added to the reaction tank, the catalyst solution containing the organic titanium compound adheres to the inner wall of the tank and is in the air. It reacts with the water content of the substance and becomes insoluble and becomes cloudy. When this occurs repeatedly, insoluble matter of the organic titanium compound is gradually deposited on the inner wall of the catalyst mixing tank and becomes a foreign substance, and the catalytic effect of the organic titanium compound is deactivated, so that there is a problem that the productivity is remarkably lowered.

An object of the present invention is not only to prevent foreign substances generated when a catalyst solution containing an organic titanium compound is quantitatively added to a reaction vessel, but also to reduce the amount of foreign substances in the polymer and to have excellent mechanical strength and color tone. An object of the present invention is to provide a high-quality polyester resin that can be suitably used for molded products, films, monofilaments, fibers and the like.

As a result of diligent studies to achieve the above object, the present inventors insolubilize the organic titanium compound and make it cloudy when a catalytic solution containing an organic titanium compound used in producing a polyester resin is quantitatively added. We have found a method for producing a polyester resin with less foreign matter and have arrived at the present invention.

That is, in the present invention, when a polyester resin is produced by subjecting a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof to an esterification reaction or a transesterification reaction, and a polycondensation reaction, the esterification reaction, At least one reaction selected from the transesterification reaction and the polycondensation reaction, a catalytic solution containing an organic titanium compound was added to the reaction vessel using an internal nozzle, and the internal nozzle was attached to the tip of the nozzle. The surface projected from the side is characterized in that the cut surface of the tip of the nozzle is horizontal and the angle between the cut surface of the tip of the nozzle and the upper side surface of the nozzle (nozzle tip angle) is 40 ° to 50 °. This is a method for producing an ester resin.

According to the present invention, when a catalyst solution containing an organic titanium compound is weighed into a reaction vessel, the organic titanium compound can be produced using a highly active catalyst without being deactivated or insolubilized and becoming cloudy. To provide a highly productive polyester resin that prevents the generation of foreign substances, has a small amount of foreign substances, has excellent mechanical strength and color tone, and can be suitably used for molded products, films, monofilaments, fibers, etc. be able to.

FIG. 1 is a schematic view illustrating a polyester resin manufacturing facility. FIG. 2 is an example of a projection drawing from the side of the tip of the nozzle used for adding the catalyst solution containing the organic titanium compound in the present invention. FIG. 3 is another example of a projection drawing from the side of the tip of the nozzle used for adding the catalyst solution containing the organic titanium compound in the present invention.

The present invention has diligently studied the above-mentioned problem, that is, a method for producing a polyester resin having a small amount of foreign matter in the polymer and high productivity, as well as preventing the generation of foreign matter, and esterification reaction and transesterification reaction. , And at least one reaction selected from the polycondensation reaction, when the catalytic solution containing the organic titanium compound is weighed into the reaction vessel, the tip of the metering nozzle is processed and internalized at a specific angle. It was clarified that the problems could be solved at once.

The polyester resin of the present invention was obtained by subjecting a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof by an esterification reaction or a transesterification reaction by a batch method or a continuous method, and then by a polycondensation reaction. , Polyester resin.

The polyester resin produced in the present invention is preferably a polybutylene terephthalate polymer using terephthalic acid as a dicarboxylic acid and 1,4-butanediol as a diol, and contains other acid components and / or other diol components. The polybutylene terephthalate copolymer used as the copolymerization component is also preferable. In this case, examples of acidic components include aromatic dicarboxylic acids such as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid and sodium sulfoisophthalic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and decalindicarboxylic acid, and Shu. Examples thereof include aliphatic dicarboxylic acids such as acids, malonic acids, succinic acids, sebacic acids, adipic acids and dodecanedioic acids. Tricarboxylic acids such as trimellitic acid may be used. Examples of diol components include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, neopentyl glycol, 1,6-hexanediol, polypropylene glycol, and polytetramethylene glycol, 1,4-. Examples thereof include alicyclic diols such as cyclohexanediol and 1,4-cyclohexanedimethanol, and aromatic diols such as 2,2-bis (4'-hydroxyphenyl) propane. Each of these copolymerization components is preferably 40 mol% or less based on terephthalic acid or 1,4-butanediol. Further, a polyester elastomer resin using a polyol as a diol is also preferable.

As a preferred embodiment of the present invention, the charged molar ratio of the diol component to the dicarboxylic acid component is preferably 1.0 to 1.5, more preferably 1.1 to 1.3.

In the present invention, a catalytic solution containing the required organic titanium compound is added to the reaction vessel at the time of at least one reaction selected from the esterification reaction, the transesterification reaction, and the polycondensation reaction. The organic titanium compound acts as a catalyst during the esterification reaction, transesterification reaction, and polycondensation reaction.

Specifically, the organic titanium compound used in the present invention is a methyl ester of titanium acid, a tetra-n-propyl ester, a tetraisopropyl ester, a tetra-n-butyl ester, a tetraisobutyl ester, a tetra-tert-butyl ester, or a tetra. -There are -ethylhexyl ester, tetraoctyl ester, phenyl ester, benzyl ester, trill ester or a mixed ester thereof. Among these, tetra-n-propyl ester (tetra-n-propyl titanate), tetra isopropyl ester (tetra-isopropyl titanate), and tetra-n-butyl ester (tetrabutoxy titanate) of titanoic acid are preferable because they can be obtained at low cost. Tetra-n-butyl ester of titanic acid (tetrabutoxytitanate) is particularly preferably used. Only one kind of these organic titanium compounds may be used, and two or more kinds may be used in combination. The amount of the organic titanium compound in the catalyst solution containing the organic titanium compound (hereinafter, may be referred to as the organic titanium compound catalyst solution) is preferably 10 to 30% by weight, more preferably 15 to 25% by weight. In the present invention, tetrabutoxytitanate is preferably used from the viewpoint of reactivity.

As the solvent of the organic titanium compound catalyst solution, for example, an organic solvent such as ethylene glycol and 1,4-butanediol is preferable, and among these, 1,4-butanediol is preferable.

If necessary, a known organic tin compound catalyst such as monobutyltin oxide or dibutyltin oxide can be used in combination with the organic titanium compound catalyst solution.

Further, in the present invention, esterification or transesterification reaction and polycondensation reaction of terephthalic acid or dimethyl terephthalate with 1,4-butanediol or the like are carried out, but these reaction conditions are not particularly limited. , Known reaction conditions in polyester production can be adopted as they are. Further, various additives such as a matting agent, a fluorescent whitening agent, a stabilizer, an ultraviolet absorber, a flame retardant, an antistatic agent, a crystal nucleating agent and the like can be appropriately used.

In the method for producing a polyester resin of the present invention, when the organic titanium compound catalyst solution is quantitatively added to the reaction vessel, it is necessary to add the organic titanium compound catalyst solution without contacting the inner wall surface of the reaction vessel. ..

Further, the reaction tank may be any of an esterification reaction tank for performing an esterification reaction, a transesterification reaction tank for performing a transesterification reaction, and a polycondensation reaction tank for performing a polycondensation reaction. Further, the reaction tank may be a catalyst mixing tank for preparing a catalyst solution containing an organic titanium compound.

Hereinafter, the present invention will be described in detail using a case where a catalyst solution containing an organic titanium compound is quantitatively added to a catalyst mixing tank to prepare a catalyst mixture, but the present invention is not limited thereto. do not have.

As a usual method of measuring and adding a catalyst solution containing an organic titanium compound to a portion other than the gas phase portion in the catalyst mixing tank, a method of directly adding to the liquid phase portion (catalyst mixture) from the middle to the lower part of the catalyst mixing tank is known. ing. In these methods, there is a problem that the measuredly added organic titanium compound is solidified and the vicinity of the measured addition port of the catalyst solution containing the organic titanium compound is easily clogged, and this cannot be sufficiently dealt with.

On the other hand, even when the catalyst solution containing the organic titanium compound is supplied to the gas phase portion of the catalyst mixing tank, if the catalyst solution is supplied while being in contact with the wall surface so as to flow down the inner wall surface of the catalyst mixing tank, the organic titanium compound is supplied during the flow down. Titanium derived from the organic titanium compound component in the catalyst solution containing the above may be insolubilized and a solid substance may be generated. When this solid matter is mixed in the catalyst mixture in the catalyst mixing tank and discharged from the esterification reaction tank without being sufficiently dispersed and reacted in the subsequent esterification reaction tank, the oligomer filter of the transfer pipe is closed and the operation is started. It may cause problems. Further, if the filter is passed through the filter or if the pipe is not provided with the filter, solid matter may be mixed into the product.

Due to such a problem, it is practically not preferable to allow the catalyst solution containing the organic titanium compound to flow down (contact) the inner wall of the catalyst mixing tank and add it by measurement.

In the method for producing a polyester resin of the present invention, in order to supply a catalyst solution containing an organic titanium compound to a gas phase portion in a catalyst mixing tank, for example, a catalyst solution addition port containing an organic titanium compound is provided above the catalyst mixing tank. It is preferable to use a method of supplying the catalyst solution containing the organic titanium compound through a connecting pipe for the catalyst solution containing the organic titanium compound.

In order to supply the catalyst solution containing the organic titanium compound into the catalyst mixing tank without contacting the inner wall surface of the catalyst mixing tank, an internal nozzle connected to the pipe and inserted into the catalyst mixing tank should be used. Is preferable. By supplying the catalyst solution containing the organic titanium compound via such an internal nozzle, it is possible to prevent the catalyst solution containing the organic titanium compound from coming into contact with the inner wall surface or dripping.

When the catalyst solution containing the organic titanium compound is quantitatively added to the catalyst mixing tank, an internal nozzle is used. The internal nozzle needs to have a horizontal cut surface at the tip of the nozzle, that is, parallel to the liquid level in the reaction vessel, on the projection surface from the side of the tip of the nozzle. Further, it is necessary to use an internal nozzle in which the angle between the cut surface of the nozzle tip and the upper side surface of the nozzle (nozzle tip angle) is 40 ° to 50 ° on the projection surface from the side of the nozzle tip. .. When the nozzle tip angle is smaller than 40 °, the area of the cut surface at the nozzle tip becomes large and the ejection angle of the catalyst solution containing the organic titanium compound becomes large, and the catalyst solution containing the organic titanium compound is sprayed on the inner wall of the catalyst mixing tank to catalyze the catalyst. Organic titanium compounds are deposited on the inner wall of the mixing tank and become foreign substances. When the nozzle tip angle becomes larger than 50 °, the organic titanium compound is accumulated on the nozzle tip by measuring and adding the catalyst solution containing the organic titanium compound repeatedly, and the nozzle tip is clogged, and the deposited organic titanium compound becomes a foreign substance. Therefore, it is not preferable. 2 and 3 show examples of projection views from the side of the nozzle tip used for adding the catalyst solution containing the organic titanium compound in the present invention, but the present invention is not limited thereto.

By using the internal nozzle having such a shape, it is possible to easily add the catalyst solution containing the organic titanium compound to the catalyst mixture solution from the gas phase portion without contacting the inner wall surface of the catalyst mixture tank. It is preferable because it can be done.

In the method for producing polyester of the present invention, the linear velocity at the time of metering and adding the catalyst solution containing the organic titanium compound to the catalyst mixing tank (volumetric flow rate of the catalyst solution containing the organic titanium compound to be metered / including the organic titanium compound). The value obtained from the cross-sectional area of the terminal opening on the catalyst mixing tank side of the metered addition line of the catalyst solution) is usually 0.01 m / sec or more, preferably 0.03 m / sec, more preferably 0.05 m / sec. That is all. The upper limit is usually 0.09 m / sec or less, preferably 0.07 m / sec or less.

Further, in the present invention, when measuring the catalyst solution containing the organic titanium compound into the catalyst mixing tank, it is preferable to purge the catalyst mixing tank with nitrogen. If not purged, the highly active organic titanium compound reacts with moisture in the atmosphere and becomes insolubilized, which is not preferable.

As described above, the catalyst solution containing the organic titanium compound may be diluted with 1,4-butanediol in the catalyst mixing tank and added to the esterification reaction tank as a catalyst mixture. The pH of 1,4-butanediol used in the catalyst mixing tank is preferably 6.5-7.5. When the pH is 6.5 to 7.5, hydrolysis of the organic titanium compound with water is suppressed, which is preferable. Although the mechanism of the pH of 1,4-butanediol is not clear, it is estimated that the pH changes depending on the content of the trace catalyst due to the difference in the production method. Further, the diol having such a pH can be preferably used as a raw material for the polyester resin.

The basic method for producing the polyester resin of the present invention is not particularly limited, but the esterification reaction tank is preferably a complete mixing tank type esterification reaction tank. The esterification reaction is preferably carried out under reduced pressure at a reaction temperature of 180 ° C. to 250 ° C., more preferably 200 ° C. to 240 ° C., and a pressure of preferably 760 mmHg or less, more preferably 100 to 700 mmHg.

Further, in order to obtain a polyester resin having excellent crystallinity, it is preferable to carry out the esterification reaction by setting the reaction temperature to 200 ° C. to 240 ° C. and the pressure to 100 mmHg to 700 mmHg. The reaction rate of the polyester oligomer after the total esterification reaction is preferably 97% or more, more preferably 99% or more. The polyester oligomer produced by the esterification reaction is then subjected to a polycondensation reaction, but the method is not particularly limited, and the polymerization conditions used in the production of a normal polyester resin can be adopted as they are. For example, the reaction temperature is preferably 230 ° C. to 260 ° C., more preferably 240 ° C. to 250 ° C.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Further, the method for producing the polyester resin by the method of measuring and adding the catalyst solution containing the organic titanium compound of Examples 1 to 6 and Comparative Examples 1 to 3 was carried out up to 50 times (50 batches), and evaluated as follows. The results of Examples 1 to 6 and Comparative Examples 1 to 3 are collectively shown in Table 1.

(1) Presence or absence of measuring nozzle:
The presence or absence of a measuring nozzle when the catalyst solution containing the organic titanium compound is measured and added to the catalyst mixing tank is shown.

(2) Tip angle of measuring nozzle:
The angle of the tip of the (1) measuring nozzle is shown in FIG.

(3) Clogged tendency of measuring nozzles Number of batches (batch):
The number of batches at the time when the required time exceeded 3 times was measured based on the charging time of the organic titanium compound in the first batch of the test into the catalyst mixing tank.

(4) Number of batches in which the measuring nozzle is clogged (batch):
The number of batches at the time when the nozzle for measuring and adding the catalyst solution containing the organic titanium compound was blocked and it became impossible to measure and add was measured.

(5) Filter replacement frequency:
Based on the liquid transfer time from the esterification reaction tank to the polycondensation reaction tank in the first batch of the test, if the required time exceeded 5 minutes from the reference time, it was judged that the filter was clogged and the filter was replaced. The number of batches at the time of performing this filter replacement was measured.

(6) Foreign matter content:
100 g of all the pelletized polymers was extracted from the inside, and those having a size of impurities contained in the chips of 1 mm ² or more were counted.

[Example 1]
FIG. 1 shows an outline of the device. 250 parts by mass of 1,4-butanediol having a pH of 7.2 heated at 100 ° C. was charged into the catalyst mixing tank 3 provided with the stirrer 2, and the inside of the catalyst mixing tank 3 was stirred at 30 rpm to measure the organic titanium compound. 4.7 parts by weight of the catalyst solution containing the organic titanium compound was weighed and added from the nozzle 1 at a linear velocity of 0.05 m / sec while purging the catalyst mixing tank with nitrogen to obtain a catalyst mixture used for the esterification reaction. In this case, the angle 7 of the tip of the organic titanium compound measuring nozzle was 45 °.

Next, 1,4-butanediol having a pH of 7.2 was charged in an esterification reaction tank 5 equipped with a stirrer 6 at a ratio of 789 parts by weight with respect to 1561 parts by weight of terephthalic acid, and mixed in the above catalyst mixing tank. The entire amount of the prepared catalyst mixture was charged from the charging line 4 into the esterification reaction tank 5, the temperature was raised while gradually controlling the temperature in the range of 190 ° C. to 240 ° C. with stirring, and the produced water was distilled off to distill out the esterified reaction product. Got

Next, 55 parts by mass of 1,4-butanediol having a pH of 7.2 heated at 100 ° C. was charged into the catalyst mixing tank 3 provided with the stirrer 2, and the inside of the catalyst mixing tank 3 was stirred at 30 rpm while using organic titanium. 5.2 parts by weight of the catalyst solution containing the organic titanium compound was weighed and added from the compound measuring nozzle 1 at a linear velocity of 0.05 m / sec while purging the catalyst mixing tank with nitrogen to obtain a catalyst mixture used for the polycondensation reaction. rice field.

Next, the catalyst mixture used for the polycondensation reaction was added to the esterification reaction product from the catalyst mixing tank 3 via the charging line 4, and the mixture was stirred and mixed with the esterification reaction product for 5 minutes to obtain an esterification reaction solution.

The amount of the organic titanium compound in the catalyst solution containing the organic titanium compound added to the catalyst mixing tank from the organic titanium compound measuring nozzle 1 is 20% by weight.

Next, the esterification reaction solution is transferred from the esterification reaction tank 9 to a polycondensation reaction tank equipped with a stirrer connected by a liquid transfer line equipped with a filter of 40 μm via the liquid transfer line in which the filter is installed. Liquid.

Next, the esterification reaction solution in the polycondensation reaction tank was subjected to a reduced pressure of 250 ° C. (1 mmHg or less), and the polycondensation reaction was terminated when the specified stirring torque was reached. The time required to reach the specified stirring torque under reduced pressure at 250 ° C. (1 mmHg or less) is defined as the polycondensation reaction time. Then, after pressurizing the polycondensation reaction tank to 0.30 MPa with nitrogen, the polymer is discharged in a strand shape via a mouthpiece (not shown) and pelletized with a cutter (not shown) while being solidified with cooling water. did.

When the polyester resin was polymerized by repeating the above method, the organic titanium compound nozzle did not tend to be clogged, and continuous operation of 50 batches was possible. The filters installed in the esterification reaction transfer line were replaced in 40 batches.

[Example 2]
In Example 1, the same procedure as in Example 1 was carried out except that the angle of the nozzle tip of the organic titanium compound to be weighed in the catalyst mixing tank was set to 50 °. As a result, the filter was replaced in 37 batches, and it was possible to operate for a sufficiently long time.

[Examples 3 and 4]
In Example 1, the same procedure as in Example 1 was carried out except that the amount of the organic titanium compound in the organic titanium compound catalyst solution to be weighed in the catalyst mixing tank was changed. As a result, it was possible to operate for a sufficiently long time without replacing the filter.

[Example 5]
In Example 1, the same procedure as in Example 1 was carried out except that the pH of the 1,4-butanediol used was 6.5. As a result, the filter replacement was 40 batches. The polycondensation reaction time was long, but it was within the usable range.

[Example 6]
In Example 1, 170 parts by weight of the copolymerization component polytetramethylene glycol (PTMG) was added to the polycondensation reaction tank, and the same procedure as in Example 1 was carried out. As a result, the filter was replaced in 40 batches, and it was possible to operate for a sufficiently long time.

[Comparative Example 1]
In Example 1, the same procedure as in Example 1 was carried out except that the nozzle of the organic titanium compound to be weighed in the catalyst mixing tank was removed. As a result, the filter replacement was shortened to 5 batches, the polycondensation reaction time was lengthened, and the foreign matter content was increased. It can be seen that the effect of the present invention cannot be obtained without a nozzle for measuring the organic titanium compound.

[Comparative Examples 2 and 3]
In Example 1, the same procedure as in Example 1 was carried out except that the angle of the nozzle tip of the organic titanium compound to be weighed in the catalyst mixing tank was changed. As a result, the filter replacement was as short as 10 batches, the polycondensation reaction time was long, and the foreign matter content was high. It can be seen that the effect of the present invention cannot be obtained when the nozzle tip angle for measuring the organic titanium compound is out of the range of 45 ° to 50 °.

1 Organic titanium compound catalytic solution metering addition nozzle (internal nozzle)
2 Stirrer 3 Catalyst mixing tank 4 Preparation line 5 Esterification reaction tank 6 Stirrer 7 Nozzle tip angle

Claims (6)

When a polyester resin is produced by subjecting a dicarboxylic acid or an ester-forming derivative thereof and a diol or a transesterifying derivative thereof to an esterification reaction or a transesterification reaction, and a polycondensation reaction, the esterification reaction, the transesterification reaction, and the weight are applied. A method for producing an ester resin in which a catalytic solution containing an organic titanium compound is added to a reaction vessel using an internal nozzle at the time of at least one reaction selected from the condensation reaction, wherein the internal nozzle is a nozzle tip. In the projected surface from the side of the part, the cut surface of the nozzle tip is horizontal, and the angle between the cut surface of the nozzle tip and the upper side of the nozzle (nozzle tip angle) is 40 ° to 50 °. A method for producing an esterified resin. The method for producing a polyester resin according to claim 1, wherein the amount of the organic titanium compound in the catalyst solution containing the organic titanium compound is 10 to 30% by weight. The reaction tank is a catalyst mixing tank for preparing a catalyst solution containing an organic titanium compound, and after preparing the catalyst solution in the catalyst mixing tank, the obtained catalyst mixture is used for an esterification reaction and / or a polycondensation reaction. The method for producing a polyester resin according to claim 1 or 2, wherein the method is characterized by the above. The method for producing a polyester resin according to any one of claims 1 to 3, wherein the organic titanium compound is tetrabutoxytitanate. The method for producing a polyester resin according to any one of claims 1 to 4, wherein the diol is 1,4-butanediol having a pH of 6.5 to 7.5. The method for producing a polyester resin according to any one of claims 1 to 5, wherein the polyester resin is any one selected from a polybutylene terephthalate polymer and a polybutylene terephthalate copolymer.

Images