JP6060728B2 - Polyester manufacturing method - Google Patents

Description

The present invention relates to a method for producing polyester. Specifically, the present invention relates to a method for producing polyester that can prevent problems of operation, quality, and equipment that are likely to occur when liquid components such as slurry are supplied to a reaction tank.

  Polyester represented by polyethylene terephthalate is a dicarboxylic acid and / or its ester-forming derivative and a diol as raw materials, and if necessary, an esterification catalyst (and / or a transesterification catalyst) or a polycondensation catalyst is added, While distilling water or alcohol produced by the reaction or a part of the raw material diol, a low polymerization reaction product (hereinafter referred to as “oligomer”) is obtained, and then a polycondensation reaction is mainly used as the raw material diol. A polyester is obtained as a target product while distilling a part of water and water.

  In particular, since the “direct esterification method” in which the final product can be obtained from the raw material dicarboxylic acid and diol without going through an ester-forming derivative has become widely used, liquid solid dicarboxylic acid at room temperature A method of supplying a solid-liquid mixture (hereinafter referred to as “slurry”) to a reaction vessel (esterification reaction vessel and / or polycondensation reaction vessel, hereinafter collectively referred to as “reaction vessel”). Generalized.

Also, with diversification of products and manufacturing methods, operation is performed with the liquid level of the esterification reaction tank lowered, and not only raw material mixtures but also catalysts, promoters and stabilizers, fine particles, pigments, dyes, etc. In many cases, an operating condition is used in which a liquid component in which auxiliaries are dissolved or dispersed in diol or water is supplied to a reaction tank.
When such a liquid component is simply supplied to the gas phase part of the reaction tank, the supplied liquid component may scatter and adhere to the inner wall surface of the reaction tank. There is a risk of corrosion, clogging of transfer pipes from the reaction tank, filters, strainers, etc. in the middle, or contamination of the adhered product into the final product.

As a method for supplying these liquid components including a slurry to a reaction vessel for polyester production while avoiding these problems, for example, the following methods are known.
(1) A method of directly adding from the middle to the lower part of the reaction tank to the liquid phase part (oligomer) (for example, FIG. 3 of Patent Document 1 and FIGS. 1 to 3 of Patent Document 2)
(2) A method of providing a pipe for circulating the oligomer outside the reaction tank and adding it to the liquid phase part (oligomer) in the pipe (for example, Patent Document 3)

Japanese Patent Laid-Open No. 5-320328 JP 2005-097634 A US Pat. No. 3,927,982

However, in the methods conventionally known in Patent Documents 1 to 3 and the like, a slurry having a low temperature is supplied to the oligomer, so that the oligomer is solidified, and there is a problem that a pipe or nozzle for supplying the slurry liquid is likely to be clogged. there were.
For this reason, a method for stably supplying a liquid component to a reaction system has been widely desired in the production of polyester.

The problem of the present invention is that, in the polyester production method, when supplying the liquid component to the reaction vessel used in the esterification step and / or the polycondensation step, the pipe and nozzle for supplying the liquid component do not clog, and An object of the present invention is to provide a polyester production apparatus equipped with a production method capable of preventing problems in operation, quality and equipment caused by the liquid component coming into contact with the inner wall surface of a reaction tank.

The gist of the present invention is as follows.
[1] A method for producing polyester comprising an esterification step and a polycondensation step, wherein at least one reaction vessel used in these steps (hereinafter referred to as an esterification reaction vessel in the esterification step and a polycondensation reaction in the polycondensation step) to collectively tank referred to as a "reactor"), di
In supplying a slurry comprising a carboxylic acid component and a diol, the slurry through a nozzle inserted into the reaction vessel, the liquid surface height of the length of the insertion portion of the nozzle the reaction mixture within the reaction vessel The slurry is supplied to the gas phase part in the reaction vessel with a change in accordance with the linear velocity of the slurry to be supplied is 0.1 m / second or more and 10 m / second or less and is brought into contact with the inner wall surface of the reaction vessel. And adding to the reaction mixture in the reaction vessel.
[2] The method for producing a polyester according to [1], wherein the slurry contains a catalyst component used in an esterification step and / or a polycondensation step.
[ 3 ] The method for producing a polyester according to [1] or [2], wherein the dicarboxylic acid component includes a terephthalic acid component.
[ 4 ] The method for producing a polyester according to any one of [1] to [3], wherein the dicarboxylic acid component includes an alicyclic dicarboxylic acid component.
[ 5 ] The method for producing a polyester according to any one of [1] to [4] , wherein the dicarboxylic acid component includes an aliphatic dicarboxylic acid component.
[ 6 ] The method for producing a polyester according to [ 5 ], wherein the aliphatic dicarboxylic acid component includes a succinic acid component.
[ 7 ] The method for producing a polyester according to any one of [ 1 ] to [ 6 ], wherein the diol contains ethylene glycol.
[ 8 ] The method for producing a polyester according to any one of [ 1 ] to [ 7 ], wherein the diol contains 1,4-butanediol.
[ 9 ] The method for producing a polyester according to any one of [ 1 ] to [ 8 ], wherein the liquid component contains a phosphorus compound.
[ 10 ] The method for producing a polyester according to [ 9 ], wherein the phosphorus compound is orthophosphoric acid and / or ethyl acid phosphate.

According to the present invention, when a liquid component is supplied to a reaction vessel used in an esterification step and / or a polycondensation step, an operation surface, a quality surface, and equipment generated by the liquid component coming into contact with the inner wall surface of the reaction vessel. An apparatus for producing polyester capable of preventing surface problems is provided.

It is an example of the whole flow diagram of the continuous polyester manufacturing apparatus of this invention. It is an example of the esterification reaction tank provided with the piping for slurry supply and nozzle corresponded to the manufacturing apparatus of this invention. It is another example of the esterification reaction tank provided with the piping for slurry supply and nozzle corresponded to the manufacturing apparatus of this invention. It is an example of the nozzle for slurry supply which provided the part which can be expanded-contracted in the front-end | tip part which can be used for the manufacturing apparatus of this invention. It is an example of the state which the supply slurry (liquid component) which is not corresponded to the embodiment of this invention is contacting the inner wall face of an esterification reaction tank. 5 is a schematic view of a corrosion state of the inner wall surface of the first esterification reaction tank of Comparative Example 1. FIG. It is an example of the whole flow diagram of the batch type polyester manufacturing apparatus of this invention.

Hereinafter, although the structure of this invention is demonstrated in detail, these are representative illustrations and are not limited to these structures.
1. Terminology The term “esterification” in the present invention includes “esterification” as well as typical “esterification” by reaction of a carboxyl group and a hydroxyl group. The “dicarboxylic acid component” in the present invention includes “dicarboxylic acid anhydride” and “ester-forming derivative of dicarboxylic acid” in addition to “dicarboxylic acid” itself. For example, “terephthalic acid component” means “terephthalic acid” and / or “terephthalic acid dialkyl ester”.
As described above, “reaction tank” may be described as one or both of “esterification reaction tank” and “polycondensation reaction tank”. In addition, as the “liquid component” supplied to the reaction vessel in the present invention, a mixed solution or slurry composed of a dicarboxylic acid component and a diol, which are raw materials for polyester, a catalyst, a cocatalyst, or a stabilizer, fine particles, pigment, dye, etc. Examples include a solution or dispersion in which an auxiliary agent is dissolved or dispersed in diol, water, or the like.

2. Polyesters and Raw Material Components (1) Various Polyesters and Raw Material Components Typical polyesters to which the production method of the polyester of the present invention can be preferably applied include, for example, the following polyesters. In the following exemplification, not only the polyester formed from each raw material component (dicarboxylic acid component / diol component) but also each component, for example, other dicarboxylic acid components and diol components of about 25% or less are used as the polyester. A case where it is a copolymerized polyester (copolyester).
Polyethylene terephthalate (dicarboxylic acid component: terephthalic acid, dimethyl terephthalate, diol component: ethylene glycol)
Polybutylene terephthalate (dicarboxylic acid component: terephthalic acid, dimethyl terephthalate, diol component: 1,4-butanediol)
Polybutylene succinate (dicarboxylic acid component: succinic acid, succinic anhydride, diol component: 1,4-butanediol)

(2) Dicarboxylic acid, diol, etc. that can be used in combination As the dicarboxylic acid other than the dicarboxylic acid component used as a raw material for the above representative polyester, for example, phthalic acid, isophthalic acid, dibromoisophthalic acid, phenylenedioxydicarboxylic acid, 4 , 4′-diphenyldicarboxylic acid, aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, and aliphatics such as glutaric acid, adipic acid, azelaic acid, and sebacic acid Examples thereof include dicarboxylic acids and their anhydrides and ester-forming derivatives.

In addition to the dicarboxylic acid, polycarboxylic acids (and their anhydrides) such as trimellitic acid and pyromellitic acid can be used in combination.
In addition, as a diol component other than the diol component used as a raw material for the above representative polyester, aliphatic diols such as diethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, polyethylene glycol, polytetramethylene ether glycol, Cycloaliphatic diols such as 4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol, 2,5-norbornane dimethylol, 4,4′-dihydroxybiphenyl, 2,2-bis (4 Examples include aromatic diols such as' -hydroxyphenyl) propane, and ethylene oxide adducts or propylene oxide adducts of 2,2-bis (4'-hydroxyphenyl) propane.

In addition to the diol, a tri- or higher functional polyol such as trimethylolmethane, trimethylolpropane, pentaerythritol, glycerin, or the like may be used in combination.
In addition, hydroxycarboxylic acids such as malic acid and citric acid may be used as a copolymerization component as required for the purpose of adjusting the physical properties of the polyester.

(3) Catalyst In the method for producing the polyester of the present invention, it is common to accelerate the reaction with a catalyst.
The esterification step proceeds even without a catalyst. For example, germanium compounds such as germanium and antimony, salts, germanium compounds such as alkoxides and antimony compounds, and titanium compounds such as titanium alkoxides and salts are preferably used as the catalyst. Further, in order to enhance the effect of the catalyst, a metal compound of “Group 1 element” and / or “Group 2 element” (long period periodic table, IUPAC 2005) as a co-catalyst, such as lithium, sodium, potassium, magnesium, A hydroxide such as calcium or an organic acid salt may be used.
These catalysts and cocatalysts are used alone or in combination of two or more. Of these, germanium compounds and titanium compounds are preferable because of their excellent activity in esterification reactions, and magnesium compounds and calcium compounds are preferable because of their excellent activity in transesterification reactions.

The usage-amount of said catalyst is 10-1000 mass ppm normally with respect to the polyester obtained.
As the catalyst used in the polycondensation step, for example, the same germanium compound, antimony compound and titanium compound as described above are used alone or in combination of two or more.
Of these, titanium compounds are preferably used because of their high activity in the polycondensation reaction. The usage-amount of a catalyst is 1-1000 mass ppm normally with respect to polyester obtained.

(4) Other auxiliaries In the method for producing the polyester of the present invention, other auxiliaries may be used in addition to the raw materials and the catalyst.
For example, phosphorus compounds such as orthophosphoric acid, orthophosphoric acid alkyl ester, ethyl acid phosphate, triethylene glycol acid phosphate, phosphorous acid, and phosphorous acid alkyl ester can be used as the stabilizer. The amount used is preferably from 1 to 1000 ppm by weight, more preferably from 2 to 200 ppm by weight, based on the resulting polyester.
Depending on the use of the polyester to be produced, fine particle components such as silica and talc, and auxiliary agents such as coloring pigments and dyes may be used.

3. Polyester Production Method and Production Equipment Hereinafter, the polyester production method of the present invention will be described using an example in which the liquid component supplied to the reaction vessel is a slurry composed of dicarboxylic acid and diol, and the reaction vessel is an esterification vessel. To do.
However, as described above, the present invention is not limited by the above description, except where otherwise provided for the liquid component and the reaction vessel.

(1) Reaction system The manufacturing method of polyester of this invention has an esterification process and a polycondensation process, and has a slurrying process as needed.
In the batch method, these steps may be performed in a smaller number of reaction vessels than in the number of steps, but in the continuous method, these steps are usually performed using (reaction) vessels corresponding to the respective steps.
As described above, the production method of the polyester of the present invention can use any of batch, semi-batch and continuous methods as a reaction method. It is also possible to carry out a combination of processes such as batch processes and esterification processes and polycondensation processes performed continuously.

For example, in the case of the batch type or the semi-batch type, the liquid level height of the reaction tank always fluctuates, so the effect of the present invention is great. Further, in the case of the continuous type, since the state in which the liquid is added to the reaction tank is almost constant, the effect of the present invention is enhanced particularly when the operation is performed with the liquid level of the reaction tank being low.
FIG. 1 illustrates a flow diagram for carrying out the continuous polyester production method, and FIG. 6 illustrates a flow diagram for a batch type.

(2) Polyester Production Process The polyester production method of the present invention is usually performed by subjecting a dicarboxylic acid component previously mixed into a slurry state and a diol to a melt polycondensation reaction of an oligomer obtained through an esterification reaction. Manufactured.
In these esterification reactions and polycondensation reactions, a catalyst is used as necessary.

<Slurry process>
The manufacturing method of the slurry used as a liquid component in the present invention is not particularly limited, and a known method in which the dicarboxylic acid component and the diol component are mixed almost uniformly to form a slurry can be used.
Examples of the manufacturing method of the slurry include a method of supplying a solid dicarboxylic acid component and a liquid diol component to a slurry preparation tank at room temperature and stirring and mixing, a method of supplying a line mixer to homogenization, and the like. It is done.

In the method using a slurry preparation tank, a diol component and a dicarboxylic acid component are charged and mixed into a container (slurry preparation tank) having a stirring shaft provided in the tank and a stirring blade connected to the stirring shaft. Thus, a uniform slurry can be obtained.
This slurry preparation tank may have an external circulation line provided with a pump in the middle. In this case, a part of the slurry can be diverted from the circulation line and supplied to the esterification step. In addition to the slurry preparation tank, a slurry storage tank that temporarily stores the prepared slurry and supplies it to the esterification step as needed may be provided.

  As a method using a line mixer, a method of producing a slurry by a line mixing method in which a diol component and a dicarboxylic acid component are supplied to a line mixer and division of a flow path is repeated as in the case of using a slurry preparation tank. In this case, the generated slurry can be fed into an esterification reaction tank or a slurry storage tank by using a driving force applied to the line mixer.

  In this slurrying step, not only the dicarboxylic acid component and the diol component are mixed almost uniformly to form a slurry, but also the catalyst, the cocatalyst, and other auxiliary agents, for example, a stabilizer such as a phosphorus compound. It can also be added and mixed. When the slurry contains a phosphorus compound, particularly a highly acidic (corrosive) component such as orthophosphoric acid or ethyl acid phosphate, the gas in the reaction vessel (esterification reaction vessel) is supplied when the slurry is supplied to the esterification process. The production method of the present invention that supplies the reaction mixture without contacting the inner wall surface of the phase portion is preferable because corrosion of the inner surface of the reaction vessel can be prevented.

<Esterification process>
In the esterification step, the raw material slurry produced in the slurrying step is heated in a esterification reaction tank under reduced pressure or pressure as necessary, and esterified while distilling off water (or alcohol) produced in the reaction. This is a step of obtaining a polyester low molecular weight product (oligomer).
The specific method is not particularly limited, and a method of obtaining an oligomer by esterifying (transesterification) a known dicarboxylic acid component and a diol component can be used.
For example, a jacket-structured reaction tank having a stirring shaft provided vertically in the tank and a stirring blade connected thereto is used as an esterification reaction tank, and the slurry obtained in the slurrying step is stirred. A method is preferably used in which an esterification reaction is performed while distilling water (alcohol) generated by the reaction by heating and circulating a heating medium (heating medium) through the jacket and heating. In addition, the esterification reaction tank may have the coil which distribute | circulates a heat medium inside a reactor.

Alternatively, an external circulation line for circulating the reaction liquid may be provided outside the esterification reaction tank, and the reaction liquid may be heated by a heat exchanger provided in the middle of the flow path. When it has an external circulation line, an oligomer can be supplied to a polycondensation process by diverting a part of reaction liquid (oligomer) from the said circulation line.
You may perform an esterification process using several reaction tanks, such as a 1st esterification reaction tank, a 2nd esterification reaction tank ..., for example. In this case, in addition to the slurry received from the slurrying step, a catalyst, a cocatalyst, a stabilizer, and other auxiliaries can be added to the first esterification reaction tank, and is one of the raw material components. A part of the diol component may be supplied. As this diol component, a part or all of the diol distilled and separated from the esterification reaction tank together with water can be used.
In the present invention, the operating conditions of the esterification step are not particularly limited, and known conditions can be appropriately used.

<Supply of liquid component in esterification process>
In the polyester production method of the present invention, the liquid component is supplied to the gas phase portion in at least one reaction vessel used in the esterification step and the polycondensation step, and without contacting the inner wall surface of the reaction vessel. It is necessary to add to the reaction mixture in the reaction vessel.

Hereinafter, this specific method will be described in detail using a case where it is applied to supply of slurry in an esterification reaction tank in an esterification step.
The “inner wall surface” of the esterification reaction tank includes a portion heated by a heat medium such as the surface of a coil through which the heat medium flows, and a stirring shaft that holds and drives a stirring blade.
As a normal method of supplying a slurry which is a liquid component (hereinafter simply referred to as “slurry”) to a portion other than the gas phase portion in the reaction vessel in which the esterification step is performed, the liquid phase portion (from the middle to the lower portion of the reaction vessel ( A method of directly adding to the reaction mixture) and a method of adding to the external circulation line are known. In these methods, since a low temperature slurry is supplied to the oligomer, there is a problem that the oligomer is solidified and the vicinity of the slurry addition port is easily clogged, and it is not always possible to sufficiently cope with various raw material compositions and operating conditions. It was.

  On the other hand, even when the slurry is supplied to the gas phase part of the reaction tank, if the slurry is supplied while being brought into contact with the wall surface so as to flow down the inner wall surface of the reaction tank, the diol component in the slurry evaporates during the flow down, Solids composed of components may be generated. If this solid matter is mixed into the reaction mixture and discharged from the esterification reaction tank without being sufficiently dispersed or reacted, the oligomer filter or polymer filter in the transfer pipe may be clogged, which may hinder operation. When passing through the filter or when the pipe is not provided with a filter, it may be mixed into the product.

Moreover, when time passes in the state which the solid substance which consists of a dicarboxylic acid component adhered to the inner wall surface, it is also considered that dicarboxylic acid corrodes the inner wall surface of a reaction tank. In particular, it is known that the inner wall surface is easily corroded when a dicarboxylic acid that becomes an acid anhydride such as succinic acid and has a vapor pressure or sublimates.
Because of such problems, it is practically undesirable to supply the slurry while flowing down (contacting) the slurry to the inner wall surface of the reaction vessel.

In the method for producing the polyester of the present invention, in order to supply the slurry to the gas phase portion in the esterification reaction tank, for example, a slurry addition port is provided at the upper part of the esterification reaction tank, and the connection from the slurrying step is provided there. It is preferable to use a method in which slurry is supplied via piping.
In order to supply the slurry, which is a liquid component, to the reaction mixture in the reaction tank without contacting the inner wall surface of the esterification reaction tank, a nozzle inserted in the esterification reaction tank connected to the pipe is used. Is preferred. By supplying the slurry via such a nozzle, it is possible to prevent the slurry from coming into contact with the inner wall surface and dripping, and the slurry can be added from a position closer to the liquid level of the reaction mixture. In addition, it is possible to prevent the slurry from being scattered in the gas phase accompanying the reaction product water or the evaporating diol.

  In addition, the amount of slurry scattered in the gas phase can be further reduced by changing the length of the insertion portion of the nozzle into the reaction tank according to the liquid level of the reaction mixture in the reaction tank. . Change the length of the insertion part of the nozzle as necessary by exchanging multiple nozzles with different lengths or using a nozzle with a part that can be expanded / contracted / changed at the tip of the insertion part. This is possible by adjusting the direction and position of the nozzle tip while observing the inside of the tank.

By using these methods, the slurry can be easily added to the reaction mixture from the gas phase portion without contacting the inner wall surface of the reaction tank, which is more preferable.
In the polyester production method of the present invention, the linear velocity (volume flow rate of slurry to be supplied / cross-sectional area of the terminal opening on the reaction tank side of the slurry supply line) when supplying the slurry to the esterification step is usually 0.1 m / Second or more, preferably 0.3 m / second or more, more preferably 0.5 m / second or more, and the upper limit is usually 10 m / second or less, preferably 5 m / second or less. By setting the linear velocity at the time of supplying the slurry to the esterification step within the above range, a phenomenon in which the supplied slurry adheres to the tip of a nozzle or the like and flows laterally (so-called teapot phenomenon) is less likely to occur. It becomes easy to add stably to a reaction mixture, without making it contact the inner wall face of an esterification reaction tank.

  If the temperature difference between the slurry supplied to the esterification step and the oligomer (reaction mixture) is as large as, for example, 50 ° C. or more, a diol accompanying a rapid temperature rise of the slurry by using the method of the present invention. It is more preferable because it can alleviate bumping of components and thermal shock to the inner wall surface of the esterification reaction tank. This effect becomes more prominent as the temperature difference between the two is 100 ° C. or higher, further 150 ° C. or higher, particularly 180 ° C. or higher.

<Melt polycondensation process>
The oligomer produced above is transferred to a polycondensation reaction tank connected through a filter, and subjected to melt polycondensation using a polycondensation catalyst under heating and decompression to obtain a polyester.
Also when adding a liquid component to this polycondensation reaction tank, the method and apparatus applied to the esterification reaction tank can be applied after adjustment as necessary.
The polyester obtained in the melt polycondensation step is subjected to the next pelletization step.

<Pelletization process / solid phase polycondensation process>
The polyester obtained by the melt polycondensation reaction is supplied to a die head connected to a polycondensation reaction tank through a transfer facility equipped with piping, gear pumps, filters, etc. as necessary, and discharged, cooled, and cut into pellets It becomes.
The obtained polyester pellets may be used as a product as a molding material as they are. However, in the case of producing a polyester having a higher molecular weight depending on the application, the pellet is heat-treated until the desired intrinsic viscosity is reached. A condensation step may be further performed.

(3) Polyester production equipment <Outline of equipment>
A polyester production apparatus according to another invention of the present application will be described.

  The polyester production apparatus suitably used in the polyester production method of the present application includes a slurrying apparatus (including related supply pipes, transfer pipes and stirring equipment) provided as necessary, and an esterification reaction tank And a polycondensation reaction tank (at least one of these two reaction tanks has a liquid component supply pipe and a liquid component supply nozzle).

The liquid component supply pipe has one or more flange portions in the vicinity of a connection point with the liquid component supply nozzle, and at least a part of the liquid component supply nozzle is at least one of the reaction tank. It is preferable to have a structure inserted into one.
Hereinafter, the polyester production apparatus of the present invention will be described using an example in which the liquid component supply pipe is a slurry supply pipe, the liquid component supply nozzle is a slurry supply nozzle, and the reaction tank is an esterification reaction tank. The invention is not limited to the following specific examples.

  FIGS. 2-1 and 2-2 illustrate preferred modes of the slurry supply pipe, the slurry supply nozzle, and the esterification reaction tank of the production apparatus of the present invention. The slurry supply pipe 8 is connected to a slurry supply nozzle 9 via a flange, and is inserted into the reaction tank 3 and opened.

<Reaction tank>
The structure of the reaction vessel (esterification reaction vessel, polycondensation reaction vessel) used in the polyester production apparatus of the present invention is not particularly limited. For example, a stirring shaft provided in the vertical direction in the vessel and a stirring blade connected thereto A reaction vessel having a heating / cooling jacket can be preferably used. Further, for heating / cooling, a coil for heat exchange may be provided in the tank, or a circulation pipe having a heat exchanger may be provided outside the tank.

<Liquid component (slurry) supply piping>
The shape, material, etc. of the slurry supply pipe 8 used in the production apparatus of the present invention are not particularly limited, taking into account the purpose and conditions of use of known pipes and the physical properties (particularly corrosiveness and wearability) of the contained components. It can be appropriately selected and used. In addition, when it is necessary to adjust the temperature of a slurry, it is preferable to use piping with the jacket structure which can distribute | circulate the hot / cold water, water vapor | steam for temperature control, etc. according to the use temperature range.

<Liquid component (slurry) supply nozzle>
The material and structure of the slurry supply nozzle 9 are not particularly limited, but a plurality of lengths of nozzles may be aligned or the esterification reaction tank side so that the length of the insertion portion into the tank can be adjusted. It is preferable to use a nozzle provided with an extendable portion at the tip portion of the tube or the connection portion with the esterification reaction tank.

  FIG. 3 exemplifies a slurry supply nozzle provided with a stretchable portion at the tip which is preferably used in the production apparatus of the present invention. This nozzle is connected to a slurry supply pipe via a flange 15, and the connection part 9-1 to the esterification reaction tank and the expandable part 9-2 of the nozzle are integrated by a helical screw. By rotating the portion, the extendable portion 9-2 moves back and forth, and the length of the entire nozzle, that is, the length of the insertion portion of the nozzle into the reaction tank is adjustable.

  In the polyester production apparatus of the present invention, it is preferable that a part of the slurry supply nozzle is inserted into the (esterification) reaction vessel. By adopting such a structure, as described above, when supplying slurry to the reaction tank, it is possible to prevent the slurry from dripping onto the inner wall of the reaction tank and to add the slurry from a position closer to the liquid level of the reaction mixture. And the scattering of the slurry in the gas phase can be suppressed.

Further, the insertion direction of the nozzle for supplying the slurry to the reaction tank and the direction of the nozzle tip are both 40 ° or less, preferably 30 ° or less, more preferably 20 ° or less, more preferably 15 ° or less with respect to the vertically downward direction. In particular, it is desirable that the angle is 10 ° or less, most preferably 0 ° (vertically downward).
When the insertion direction of the nozzle is not vertically downward, the direction is preferably a direction away from the nearest inner wall surface as viewed from vertically above. Here, the “nozzle insertion direction” refers to the flow direction of the liquid in the nozzle near the flange connecting the nozzle and the reaction vessel. These directions (angles) can be adjusted by adjusting the angle of the flange surface connecting the nozzle and the reaction vessel (preferably horizontal) or by bending the tip of the nozzle to a desired angle.

  When the nozzle insertion method satisfies the above conditions, even if the nozzle insertion length is increased, the tip of the nozzle can be kept at an appropriate distance from the axis of the stirring blade and the opposing inner wall surface. This is preferable because the adjustable range is wide.

<Connection between liquid component supply pipe and liquid component supply nozzle>
In the polyester production apparatus of the present invention, the liquid component (slurry) supply pipe has one or more flange portions in the vicinity of the connection point with the liquid component (slurry) supply nozzle. The position of the flange is "near" means that the pipe and the nozzle are separated from each other with good workability by dividing the flange and the connecting portion between the slurry supply pipe and the nozzle. Specifically, the linear distance between the two is within 3 m, preferably within 1.5 m, more preferably within 0.75 m. Thus, the intermediate pipe between the slurry supply pipe and the slurry supply nozzle can be easily removed, and therefore the slurry supply nozzle can be replaced quickly, and the slurry supply nozzle is inserted into the reaction tank. The length of the part can be easily adjusted.

<Material>
The material of the polyester production apparatus of the present invention includes not only the raw material dicarboxylic acid component and diol component, but also the added catalyst, auxiliary agent, stabilizer, compound produced by esterification reaction or thermal decomposition, and mixtures thereof. It is preferable to select the material in consideration of the corrosion resistance to the material. For example, SUS304, SUS316, SUS316L, SUS317L, SUS410, SUS430, and the like are preferably used among stainless steels defined by Japanese Industrial Standards.
Note that it is more preferable that the slurry supply pipe, the slurry supply nozzle, the esterification reaction tank, and the polycondensation reaction tank are all made of the same material because corrosion caused by contact of different materials can be prevented. .

<Others>
The polyester production apparatus of the present invention has been described above using an example in which the liquid component supply pipe is a slurry supply pipe, the liquid component supply nozzle is a slurry supply nozzle, and the reaction tank is an esterification reaction tank. However, the present invention is not limited to the range exemplified in the above description.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely using an Example, this invention is not limited by a following example, unless the summary is exceeded.
1. Experimental Apparatus In Example 1 and Comparative Example 1, polyester was continuously produced using a polyester production apparatus according to the flow shown in FIG.
(1) Slurry process Slurry preparation tank 1: having a stirrer, dicarboxylic acid feeding pipe and diol feeding pipe Slurry storage tank 2: having a stirrer and slurry receiving pipe

(2) Esterification process 1st esterification reaction tank 3: Complete mixing type equipped with jacket and internal coil capable of circulating heat medium, stirrer, gas-liquid separation tower, raw material receiving port, catalyst charging pipe, reactant transfer pipe Reaction tank (material of tank inner surface: SUS316L)
Second esterification reaction tank 4: Completely mixed reaction tank (jacket inner surface material: equipped with jacket capable of circulating heat medium, stirrer, gas-liquid separation tower, raw material receiving port, catalyst charging pipe, reactant transfer pipe) (SUS316L)

(3) Polycondensation Step First Melt Polycondensation Reaction Tank 5: Completely mixed melt polycondensation reaction equipped with a jacket and internal coil capable of circulating a heat medium, a stirrer, a gas-liquid separation tower, an oligomer receiving port, and a catalyst charging pipe Tank (Material of tank inner surface: SUS304)
Second and third melt polycondensation reaction tanks 6 and 7: Plug flow type melt polycondensation reaction tank (inside tank) equipped with jacket capable of circulating heat medium, stirrer, gas-liquid separation tower, polymer inlet and polymer outlet Surface material: SUS304 for both

(4) Connection of each apparatus Each tank consists of a slurry preparation tank, a slurry storage tank, a first esterification reaction tank, a second esterification reaction tank, a first melt polycondensation reaction tank, a second melt polycondensation reaction tank, and In the order of the third melt polycondensation reaction tank, they are connected by a pipe provided with a transfer pump.
Further, a bypass pipe that directly connects the first esterification reaction tank and the first melt polycondensation reaction tank is also connected so that the operation without passing through the second esterification reaction tank is possible. (Not shown)
The slurry is supplied from the slurry storage tank to the first esterification reaction tank through a slurry supply pipe-slurry supply nozzle, and the oligomer supply to the first melt polycondensation reaction tank is a transfer having an oligomer filter. This was done via piping.

(5) Pelletization The polyester obtained by the reaction is discharged in a molten state from the third melt polycondensation reaction tank, is formed into a strand shape by a die plate through a polymer filter, is taken out, cooled with water, and then pelletized. And pelletized.

2. Production example
[Example 1]
(1) Raw material dicarboxylic acid: terephthalic acid diol: ethylene glycol catalyst: germanium dioxide auxiliary agent: orthophosphoric acid

(2) Slurry step In a slurry preparation tank, 225 parts by mass of terephthalic acid and 150 parts by mass of ethylene glycol are stirred and mixed, and the addition amount as germanium is 104 to 120 masses with respect to the target product polyethylene terephthalate. A slurry was prepared by adding an aqueous solution of germanium dioxide so as to be ppm and an ethylene glycol solution of normal phosphoric acid so as to be 40 mass ppm as phosphorus.
The prepared slurry was transferred to a slurry storage tank and stored under stirring.

(3) Esterification step The slurry is moved from the slurry storage tank to the first esterification reaction tank at an angle of 15 ° with respect to the vertical downward direction from the nearest inner wall surface as viewed from the vertical upper side (center direction of the reaction tank). ) Was continuously supplied at 140 parts by mass / hour via a slurry supply nozzle inserted into the tank.
Average retention while distilling ethylene glycol, water, etc. and BR> by-product through gas-liquid separation under conditions of 260 ° C in the tank and pressure 213 kPaA (A indicates absolute pressure, the same applies hereinafter) The reaction was carried out for 5 to 6 hours.

The liquid level in the first esterification reaction tank during the reaction was 48 to 55% with respect to the total height in the tank. The slurry is supplied at a linear velocity of 0.12 m / sec from the gas phase portion in the first esterification reaction tank, and the nozzle for slurry supply is not blocked during operation. It was added to the esterification reaction mixture (oligomer) without contacting the inner wall surface.
The oligomer obtained in the first esterification reaction tank was continuously supplied to the second esterification reaction tank via a transfer pipe.
Further, ethylene glycol was continuously supplied to the second esterification reaction tank at 5 to 6 parts by mass / hour, and the conditions were that the temperature in the tank was 260 ° C., the pressure was 106 kPaA, and the average residence time was 1.6 to 2.0 hours. The oligomerization was carried out while distilling out by-products such as glycol and water.

(4) Melt polycondensation step The oligomer obtained in the second esterification reaction tank is supplied to the first melt polycondensation reaction tank, and then sequentially into the second melt polycondensation reaction tank and the third polycondensation reaction tank. Supply, stepwise increase the temperature in the range of 275 ° C to 283 ° C, and stepwise decrease the pressure in the range of 8 kPaA to 0.1 kPaA to produce poly (ethylene terephthalate) with the desired degree of polymerization did.
The polyethylene terephthalate obtained in the third polycondensation reaction tank was taken out from the die plate in a strand form via a polymer filter, cooled with water, and then pelletized using a pelletizer.

(5) Observation of the reactor The operation was continued for 7 days under the above production conditions. After the operation was completed, each reactor was depolymerized and washed with triethylene glycol, cooled to room temperature, and then purified water. Washed.
After cleaning, the inside of the first esterification reaction tank, which is considered to be most affected by the carboxylic acid component as a raw material, was confirmed, but no corrosion of the inner surface or reduction in material thickness was observed.

[Comparative Example 1]
(1) Raw material dicarboxylic acid: succinic acid and a small amount of malic acid diol: 1,4-butanediol catalyst: 1,4-butanediol solution of tetrabutoxytitanium / magnesium acetate / ethyl acid phosphate

(2) Slurry step In a slurry preparation tank, 151 parts by mass of succinic acid, 149 parts by mass of 1,4-butanediol, and 0.25 part by mass of malic acid were stirred and mixed to prepare a slurry.
The prepared slurry was transferred to a slurry storage tank and stored at 40 ° C. with stirring.

(3) Esterification step In this example, the second esterification reaction tank was not used, and the esterification reaction was carried out using only the first esterification reaction tank.
The slurry was continuously supplied at 82 parts by mass / hour via a slurry supply nozzle inserted into the tank in the same arrangement as in Example 1. Further, while continuously supplying 1,4-butanediol from another nozzle at 6 parts by mass / hour, 1,4-butanediol, water, tetrahydrofuran, and the like were used under the conditions of an internal temperature of 230 ° C. and a pressure of 106 kPaA. The reaction was carried out under the condition of an average residence time of 2.8 to 3.2 hours while distilling the by-product through gas-liquid separation or the like.
The liquid level in the first esterification reaction tank during the reaction was 17 to 21% with respect to the total height in the tank. The slurry was supplied at a linear velocity of 0.079 m / sec from the gas phase portion in the first esterification reaction tank. A part of the slurry was in contact with the inner wall surface of the first esterification reaction tank and then added to the esterification reaction mixture (oligomer).

(4) Melt polycondensation step The amount of the catalyst added to the oligomer obtained in the first esterification reactor is 50, 33 as titanium, magnesium, and phosphorus, respectively, with respect to the target polybutylene succinate. , And added to the first melt polycondensation reaction tank, and then sequentially supplied to the second melt polycondensation reaction tank and the third melt polycondensation reaction tank. A polybutylene succinate having a desired degree of polymerization was produced by increasing the pressure stepwise in the range of 245 ° C. to 245 ° C., and decreasing the pressure stepwise in the range of 3 kPaA to 0.1 kPaA.
The polybutylene succinate obtained in the third polycondensation reaction tank was taken out from the die plate in a strand form via a polymer filter, cooled with water, and then pelletized using a pelletizer.

(5) Observation of the reaction apparatus In the same manner as in Example 1, after the operation was continued for 7 days under the above production conditions, the inside of each reaction tank was washed and the inside of the first esterification reaction tank was confirmed. As shown schematically in Fig. 2, mild corrosion is seen on the inner surface of the reaction tank corresponding to a liquid level height of 20 to 40% below the slurry supply nozzle, and the material of the corrosion site is about 0.1 to 0.3 mm. It was thinning.
Considering such a corrosion state, as shown schematically in FIG. 4, this corrosion is caused by the supply of slurry at a low flow rate and the occurrence of the teapot phenomenon, and the liquid level of the reaction liquid is also low. Since the slurry contacted the inner wall surface of the first esterification reaction tank, it is considered that the slurry was generated by succinic acid in the slurry.

[ Reference example ]
(1) Reactor This reference example was carried out batchwise using a production apparatus as shown in FIG.
That is, as the esterification apparatus, a fully mixed esterification reaction tank (within the tank) and a heating medium jacket and internal coil, a stirrer, a gas-liquid separation tower, a raw material inlet, a catalyst charging pipe, and a reactant transfer pipe Surface mixing: SUS316L), and a polycondensation unit connected to this with a pipe, a heat mixing jacket, a stirrer, a gas-liquid separation tower, an oligomer inlet, and a catalyst charging pipe. A polycondensation reaction tank (material on the inner surface of the tank: SUS304) was used.

(2) Manufacture of polyester Polyethylene terephthalate was manufactured batchwise using dimethyl terephthalate as the dicarboxylic acid component and ethylene glycol as the diol using the above apparatus.
Specifically, 100 parts by mass of dimethyl terephthalate and 65 parts by mass of ethylene glycol are charged into the esterification reaction tank, heated to 150 ° C. to melt dimethyl terephthalate, and then 0.09 with respect to the resulting polyester composition. After adding magnesium acetate tetrahydrate as an ethylene glycol solution (concentration 6.5 mass%) so as to be part by mass, the temperature was raised to 225 ° C. over 3 hours under normal pressure stirring, and further at this temperature for 1 hour. After stirring for 15 minutes, methanol was distilled off to substantially complete the transesterification reaction, thereby obtaining a polyester oligomer.

  The ethylene glycol solution of magnesium acetate tetrahydrate, which is a catalyst component in the form of the solution, is viewed from the upper vertical direction at an angle of 22 ° with respect to the vertical downward direction from the catalyst charging pipe connected to the top plate of the reaction vessel. By supplying it to the gas phase part of the reaction tank via a nozzle inserted in the esterification reaction tank so that it is in a direction away from the nearest inner wall surface (center direction of the reaction tank), The nozzle was blocked during the supply of the solution, and the solution was added to the reaction mixture without contacting the inner wall of the reaction vessel.

  The obtained polyester oligomer was transferred to the polycondensation reaction tank, and an ethylene glycol solution of normal phosphoric acid (concentration 3.6% by mass) as a stabilizer was 0.03 parts by mass with respect to the polyester obtained as phosphoric acid. Then, an ethylene glycol solution of antimony trioxide (concentration of 1.8% by mass) was added as a polycondensation catalyst so as to be 0.04 parts by mass as antimony trioxide with respect to the obtained polyester.

  The ethylene glycol solution of orthophosphoric acid and the ethylene glycol solution of antimony trioxide are both charged vertically downward with the tip inserted into the reaction tank from the catalyst preparation pipe connected to the top plate of the polycondensation reaction tank. By supplying to the gas phase part of the reaction tank via the nozzle, the nozzle is blocked during the supply of these solutions, and the reaction mixture is not brought into contact with the inner wall surface of the reaction tank. (Oligomer).

  Next, the polycondensation reaction tank was depressurized from 101.3 kPaA (atmospheric pressure) to 0.4 kPaA over 85 minutes with stirring, and then maintained at 0.4 kPaA and increased from 225 ° C to 280 ° C over 2 hours. The polycondensation reaction was performed by heating and holding at 280 ° C. for 1.5 hours to obtain polyethylene terephthalate having an intrinsic viscosity of 0.62 dL / g.

(3) Observation of reaction tank After operating a total of 32 batches under the manufacturing conditions described above, the inside of each reaction tank was washed in the same manner as in Example 1, and then in the esterification reaction tank and melt polycondensation. Although the inside of the reaction vessel was confirmed, neither corrosion on the inner surface nor reduction in material thickness was observed.

According to the present invention, when a polyester is produced, a liquid component supplied to a reaction vessel, particularly a slurry made of dicarboxylic acid and diol, is generated by contacting an inner wall surface of an esterification reaction vessel or a polycondensation reaction vessel. It is possible to prevent problems in operation and quality such as generation of foreign matter and filter blockage, and problems in facilities such as corrosion of the inner wall surface of the reaction tank.
Further, according to the present invention, there is provided a polyester production apparatus provided with a supply nozzle having a structure capable of effectively preventing the liquid component from coming into contact with the inner wall surface of the reaction tank when supplying these liquid components to the reaction tank. .

1: slurry preparation tank 2: slurry storage tank 3: first esterification reaction tank 4: second esterification reaction tank 5: first melt polycondensation reaction tank 6: second melt polycondensation reaction tank 7: third melt polycondensation Reaction tank 8: Slurry supply pipe 9: Slurry supply nozzle 9-1: Part of the slurry supply nozzle (connection to the esterification reaction tank)
9-2: Part of the slurry supply nozzle (expandable part at the tip)
10: Stirring shaft 11: Stirring blade 12: Reactant (oligomer) outlet 13: Heat medium circulation jacket 14: Heat medium circulation inner coil 15: Flange 16 for connecting the slurry supply nozzle and the esterification reaction tank : Oligomer liquid surface 17: Spreading state of slurry droplet 18: Corrosion spot on the inner wall surface of the first esterification reaction tank (Comparative Example 1)
19: Esterification reaction tank 20: Melt polycondensation reaction tank

Claims (10)

A method for producing a polyester comprising an esterification step and a polycondensation step,
At least one reaction vessel used in these steps (hereinafter, the esterification reaction vessel in the esterification step and the polycondensation reaction vessel in the polycondensation step are collectively referred to as a “reaction vessel”) is composed of a dicarboxylic acid component and a diol. in supplying the slurry, the slurry through a nozzle inserted into the reaction vessel, the length of the insertion portion of the nozzle by changing depending on the liquid level of the reaction mixture within the reaction vessel the Supply to the gas phase part in the reaction tank,
The linear velocity of the slurry to be supplied is 0.1 m / second or more and 10 m / second or less,
And it adds to the reaction mixture in a reaction tank, without making it contact the inner wall surface of this reaction tank, The manufacturing method of polyester characterized by the above-mentioned. The method for producing a polyester according to claim 1, wherein the slurry contains a catalyst component used in the esterification step and / or the polycondensation step. Method for producing a polyester according to claim 1 or 2 wherein the dicarboxylic acid component is characterized in that it comprises a terephthalic acid component. The said dicarboxylic acid component contains an alicyclic dicarboxylic acid component, The manufacturing method of the polyester of any one of Claims 1-3 characterized by the above-mentioned. The said dicarboxylic acid component contains an aliphatic dicarboxylic acid component, The manufacturing method of the polyester of any one of Claims 1-4 characterized by the above-mentioned. The method for producing a polyester according to claim 5 , wherein the aliphatic dicarboxylic acid component includes a succinic acid component. The said diol contains ethylene glycol, The manufacturing method of the polyester of any one of Claims 1-6 characterized by the above-mentioned. The said diol contains 1 , 4- butanediol, The manufacturing method of the polyester of any one of Claims 1-7 characterized by the above-mentioned. The method for producing a polyester according to claim 1 , wherein the liquid component contains a phosphorus compound. The method for producing a polyester according to claim 9 , wherein the phosphorus compound is orthophosphoric acid and / or ethyl acid phosphate.

Images