JP2006089761A - Method for producing polybutylene terephthalate and apparatus for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method or apparatus for continuously producing polybutylene terephthalate in good profitability. <P>SOLUTION: This method for continuously producing the polybutylene terephthalate, comprising feeding a mixture of an aromatic dicarboxylic acid or its derivative and a glycol compound as raw materials into the first reactor to produce the oligoester having an average polymerization degree of 3 to 7 at a temperature of 220 to 275 degree, producing a low polymer having an average polymerization degree of 20 to 40 at a temperature of 220 to 280 degree at a pressure of the atmospheric pressure to 133 Pa in the second reactor, and then polycondensing the low polymer at a temperature of 220 to 280 degree at a pressure of 220 to 13.3 Pa in the third reactor to produce the polybutylene terephthalate having an average polymerization degree 70 to 180 is characterized in that the third reactor is equipped with a rotatable stirring rotor having stirring blade blocks corresponding to the viscosity of a treating liquid therein, and does not have a rotation shaft in the center of the stirring blades. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a continuous production method or production apparatus for polybutylene terephthalate.

  Polybutylene terephthalate (hereinafter referred to as PBT) resin has excellent crystallization characteristics and excellent mechanical properties, electrical characteristics, heat resistance, etc., and has recently been applied to electrical, electronic parts, mechanical parts, automotive applications, etc. Demand is growing.

  The following method can be considered as a manufacturing method of PBT. Add terephthalic acid dialkyl ester with dimethyl terephthalate as main ingredient and glycol with 1,4-butanediol (hereinafter referred to as BD) as main ingredients to mixing tank at appropriate ratio, and add and adjust transesterification catalyst Then, it is sent to a transesterification reaction tank set at a predetermined reaction temperature by a pump. In this transesterification reaction, two to three stirring tanks with stirring blades are arranged in series, and methanol produced as a side reaction product, tetrahydrofuran (hereinafter referred to as THF) generated by decomposition of BD, and water are distilled in a distillation column. To separate. Next, a polymerization catalyst is added and the polymerization reaction step is performed. First, a plurality of vertical stirring tanks and horizontal stirring tanks are installed as a prepolymerization process, and a horizontal stirring tank is installed as a final polymerization process. In the tanks of these polymerization processes, a condenser is installed to remove BD, THF, and water as by-products, and the apparatus is operated in a reduced pressure atmosphere. In the conventional continuous production process of PBT, the number of reaction tanks is 4 to 6 cans, each reaction tank is equipped with a stirring blade and its power source, and has a distillation column and a condenser for separating and removing byproducts. is set up. Furthermore, since the polymerization process is operated in a reduced pressure atmosphere, the vacuum means must be operated by a separate apparatus, and the operation of the manufacturing apparatus requires high maintenance costs and equipment costs.

  In the above manufacturing method, many devices are required, and the energy for operating plant equipment is large, which is considered to be inferior in economic efficiency.

  An object of the present invention is to provide a continuous production method or apparatus for polybutylene terephthalate which is excellent in economic efficiency.

  The purpose is to use terephthalic acid (hereinafter referred to as TPA) and 1,4-butanediol (BD) as raw materials for the production of PBT, and a direct esterification reaction step, a prepolymerization reaction step, and a final polymerization reaction step, respectively, in one tank. Is achieved by doing

  More specifically, the above object is achieved by supplying a raw material having a molar ratio of aromatic dicarboxylic acid or a derivative thereof to glycols in the range of 1: 1.2 to 1: 3.0 in the first reactor. The raw material is reacted at a temperature of the first reactor of 220 to 275 degrees to produce an oligoester or polyester having an average polymerization degree of 3 to 7 or less as a product, and the first reactor is connected to the first reactor. The product supplied from the reactor is fed, the temperature of the second reactor is set to 220 to 280 degrees, the pressure is set in the range of atmospheric pressure to 133 Pa, the product is reacted, and the average degree of polymerization is low from 20 to 40. A polymer is produced, and the low polymer supplied from the second reactor is supplied to the third reactor. The temperature of the third reactor is 220 to 280 degrees, and the pressure is 220 to 13.3 Pa. The low polymer is reacted in a range, A polybutylene terephthalate continuous production method for producing polybutylene terephthalate by polycondensation from a degree of polymerization of 70 to 180 degrees, wherein the third reactor is a stirring rotor rotating inside thereof, and the viscosity of the treatment liquid is increased. This is achieved by a continuous production method of polybutylene terephthalate which has a stirring rotor having a plurality of corresponding stirring blade blocks and does not have a rotating shaft at the center of the stirring blade.

Alternatively, a raw material in which the molar ratio of the aromatic dicarboxylic acid or derivative thereof and the glycol as the raw material is in the range of 1: 1.2 to 1: 3.0 is supplied, and the temperature is adjusted to 220 to 275 degrees. A first reactor in which an oligoester or polyester having an average polymerization degree of 3 to 7 or less is produced as a product by reacting the raw materials, and the product supplied from the first reactor is supplied, A second reactor in which a low polymer having an average polymerization degree of 20 to 40 is produced by reacting the product at a temperature of 220 to 280 degrees and a pressure of atmospheric pressure to 133 Pa, and the second reactor; The low polymer supplied from the reactor is supplied at a temperature of 220 degrees to
A polybutylene comprising a third reactor for producing polybutylene terephthalate by reacting the low polymer under a pressure of 280 ° C. and a pressure of 220 to 13.3 Pa, and polycondensing the polymer to an average polymerization degree of 70 to 180 ° An apparatus for continuously producing terephthalate, wherein the third reactor includes an agitation rotor having a plurality of agitation blades corresponding to the viscosity of the processing liquid, the agitation rotor rotating inside the third reactor. This is achieved by an apparatus for continuously producing polybutylene terephthalate having no rotating shaft in the part.

  Furthermore, the third reactor has an inlet and an outlet for the liquid to be treated at the lower end and the lower end at the other end in the longitudinal direction of the horizontal cylindrical container body, respectively, and an outlet for volatiles at the upper part of the main body. Is achieved.

  Furthermore, this is achieved by setting the rotation speed range of the stirring blade of the third reactor to 0.5 rpm to 10 rpm.

  Furthermore, it is achieved by operating the total reaction time of the first reactor, the second reactor and the third reactor between 4 and 9 hours.

  FIG. 1 shows an embodiment of the present invention. FIG. 1 is a diagram illustrating an apparatus for a continuous production process of PBT according to the present invention.

  As an industrial method for producing polybutylene terephthalate, the direct esterification method is very advantageous economically. In the figure, reference numeral 1 denotes a raw material adjusting tank for mixing and stirring TPA and BD, which are PBT raw materials, at a predetermined ratio. In this stage, additives such as a polymerization reaction catalyst, a stabilizer, and a quality regulator may be added.

  Examples of the polymerization reaction catalyst include metal compounds such as organic titanium, organic tin, and organic zirconia. Not only the reaction rate varies depending on the type and combination of the catalyst used, but also the quality such as hue and thermal stability of the produced PBT. Has a major impact on Furthermore, since these reactions are carried out at high temperatures for a long time due to the presence of the catalyst, various side reactions are involved, the polymer is colored, the THF content and the terminal carboxyl group concentration are increased to an appropriate value, Physical properties such as quality deterioration and strength reduction of PBT may decrease.

In order to improve such problems, organic titanium currently used most industrially is superior in price and performance. However, even when this catalyst is used, the resulting polybutylene terephthalate polymer is inevitably colored. For this reason, a phosphorus stabilizer (for example, phosphoric acid, trimethyl phosphate, triphenyl phosphate, etc.) is used in combination as a stabilizer. As another manufacturing process, it is conceivable to stabilize the quality by devising the charging position of the polymerization catalyst or stabilizer. In a normal process, the amount of catalyst is 20 to 85 in terms of titanium metal equivalent.
It is preferable to use 0 to 600 ppm in terms of the P metal concentration as required.

  The raw material adjusted as described above is supplied via a supply line 2 for supplying the raw material to the esterification reaction tank 3. The outer periphery of the esterification reaction tank (first reactor) 3 has a jacket structure (not shown) in order to keep the treatment liquid at the reaction temperature. Inside the liquid is a multi-can type heat as a means for heating the liquid. An exchanger 4 is installed to heat the treatment liquid with an external heat source, and the reaction proceeds while circulating the liquid inside by natural circulation. Here, the most desirable reactor type is preferably a Calandria type in which the processing liquid in the reactor is naturally circulated by utilizing the evaporation effect of a by-product generated by the self-reaction of the esterification reaction. Since this type of reactor does not require an external stirring power source, the configuration of the apparatus is simple, and a shaft sealing device for the stirring shaft is not required, and the production cost of the reactor is reduced.

  As an example of such a reactor, an apparatus as shown in Japanese Patent Application No. 8-249769 is desirable. However, in the present invention, this apparatus is not limited, and a reactor having a stirring blade may be used for process reasons. In the first reactor, water produced by the reaction becomes water vapor, and forms the gas phase part 5 together with the vaporized BD vapor and THF vapor.

  At this time, the recommended reaction conditions are a temperature of 220 to 270 degrees and a pressurized condition. The gas in the gas phase section 5 is separated into water, THF, and BD by a rectification column (not shown) provided on the upstream side thereof, removed from the water and the THF system, and BD is again subjected to a purification process and the like. Returned to the system. As an advantage of the present invention, the number of rectification towers can be reduced to one by treating the esterification process in one reactor, and not only the production cost of the rectification tower but also the number of pipes and valves can be controlled. The number of devices can be reduced, resulting in a significant reduction in equipment costs.

  Usually, the reaction time required for esterification is 2 to 5 hours, but the optimum value of the optimum reaction time is determined by the mixing ratio of raw materials TPA and BD, reaction temperature, and pressure. The treatment liquid having passed a predetermined reaction time in the esterification reaction tank 3 reaches a predetermined esterification rate, and is supplied to an initial polymerization tank (second reactor) 7 by an oligomer pump 15 provided in the middle of the connecting pipe 6. . Further, an intermediate addition device 16 is provided in the communication pipe, and addition or addition of a polymerization catalyst or addition of an additive is performed as necessary. There is no problem in adding various commonly used additives such as an antistatic agent and an ultraviolet absorber in this intermediate addition device, and a dispersion device such as a static mixer or an inline mixer is installed in the connecting pipe downstream of the addition device. You may do it.

  Thereafter, the treatment liquid supplied to the initial polymerization tank is heated to a predetermined reaction temperature by the heat exchanger 8 to perform a polycondensation reaction to increase the degree of polymerization. The reaction conditions at this time are 220 to 280 degrees, the pressure is 266 to 133 Pa, and the degree of polymerization is about 20 to 40. Although the initial polymerization tank shown in this example is described using a reactor having no stirring blade, it is not necessarily limited to this type of reactor. However, in the initial polymerization stage, the reaction is a stage in which the polymerization reaction rate is a rule of the reaction rate, and the reaction proceeds smoothly if a sufficient amount of heat necessary for the reaction is supplied. From this point of view, the treatment liquid does not need to be subjected to unnecessary stirring action by the stirring blade, and only the BD generated by the polycondensation reaction is removed from the system. As an optimum reactor for such operation, an apparatus as shown in Japanese Patent Application No. 8-233855 is desirable.

  BD generated by the reaction, water and THF are vaporized in the gas phase portion 9 maintained in a reduced-pressure atmosphere, condensed in a condenser provided upstream thereof, and then discharged out of the system. As an advantage of the present invention, the number of condensers can be reduced to one by treating the initial polymerization process in one reactor, reducing not only the production cost of condensers but also the number of pipes and valves. This greatly reduces the equipment cost.

  The processing liquid that has passed a predetermined reaction time in the initial polymerization tank (second reactor) 7 is supplied to the final polymerization machine (third reactor) 11 through the communication tube 10. In the final polymerization machine, a polymer having a desired degree of polymerization is produced by increasing the degree of polymerization by further proceeding the polycondensation reaction while receiving a good surface renewal action by the stirring blade 12 having no stirring shaft at the center. As an apparatus optimal as the final polymerization machine (third reactor), the apparatus described in Japanese Patent Application No. 8-233857 has the most excellent surface renewal performance and power consumption characteristics. In addition, since the viscosity range of the treatment liquid is wide, it has been possible to use a single apparatus to perform treatment by dividing into two tanks in the past, which greatly reduces the apparatus cost. In view of quality, the residence time of the entire polymerization process is in an optimal range of 2 to 4 hours.

  When PBT is continuously manufactured in the above apparatus configuration, the number of reactors is reduced as compared with the conventional apparatus configuration, so that the production cost of the apparatus can be saved and the distillation accompanying the apparatus with the decrease in the number of apparatuses. The number of towers and condensers can be reduced, piping and instrumentation parts and valves connecting them can be saved significantly, and utility costs such as vacuum sources and heat transfer devices are greatly reduced, leading to lower running costs. is there.

  Table 1 shows an experimental example.

  The intrinsic viscosity of the experimental example is a value calculated from the measurement result at a measurement temperature of 30 ° C. using an Ostwald viscometer using 50 wt% phenol and 50 wt% tetrachloroethane as a solvent, and the acid value is 230 ° C. using benzyl alcohol as a solvent. It is a value measured by dissolving with heating for 5 minutes and performing neutralization titration. As shown in Table 1, it was produced by continuous production operation of direct esterification of TPA and BD, and high-quality PBT having an intrinsic viscosity of 0.7 or more and an acid value of 25 or less was obtained only by melt polymerization.

  According to the above embodiment, the continuous production equipment for PBT is made into three reactors of the direct esterification process, the pre-polymerization process, and the final polymerization process, thereby improving the efficiency of the entire apparatus and saving energy of the production equipment. Operate economically.

It is a block diagram which shows one Example of the continuous manufacturing apparatus of the polybutylene terephthalate by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Raw material adjustment tank, 2 ... Raw material supply line, 3 ... Esterification reaction tank, 4,8 ... Heat exchanger, 5,9 ... Gas phase part, 6,10 ... Communication pipe, 7 ... Initial polymerization tank, 11 ... Final polymerization machine, 12 ... stirring blade, 13 ... polymer, 14 ... stirring power source, 15 ... oligomer pump, 16 ... intermediate addition device.

Claims (8)

In the first reactor, a raw material having a molar ratio of aromatic dicarboxylic acid or derivative thereof to glycols in the range of 1: 1.2 to 1: 3.0 is supplied, and the temperature of the first reactor is set to 220 degrees. Reacting the raw materials at ˜275 degrees to produce an oligoester or polyester having an average degree of polymerization of 3 to 7 or less as a product;
The product supplied from the first reactor is supplied to the second reactor, and the product is reacted by setting the temperature of the second reactor to 220 to 280 degrees and the pressure from atmospheric pressure to 133 Pa. A low polymer having an average degree of polymerization of 20 to 40,
The low polymerization product supplied from the second reactor is supplied to a third reactor, the temperature of the third reactor is set to 220 to 280 degrees, and the pressure is set to a range of 220 to 13.3 Pa. A continuous production method of polybutylene terephthalate in which a polybutylene terephthalate is produced by reacting a product and polycondensing from an average polymerization degree of 70 to 180 degrees,
Polybutylene having a stirring rotor in which the third reactor rotates, the stirring rotor having a plurality of stirring blade blocks corresponding to the viscosity of the treatment liquid, and having no rotating shaft at the center of the stirring blade Continuous production method of terephthalate. A method for continuously producing polybutylene terephthalate according to claim 1,
The third reactor has an inlet and an outlet for the liquid to be treated at the lower end and the lower end in the longitudinal direction of the horizontal cylindrical container body, respectively.
A method for continuously producing polybutylene terephthalate having a volatiles outlet at the top of the main body. A method for continuously producing polybutylene terephthalate according to claim 1 or 2,
A method for continuously producing polybutylene terephthalate, wherein the rotation speed range of the stirring blade of the third reactor is 0.5 rpm to 10 rpm. A method for continuously producing polybutylene terephthalate according to any one of claims 1 to 3,
A continuous production method of polybutylene terephthalate, wherein the total reaction time of the first reactor, the second reactor, and the third reactor is operated for 4 to 9 hours. The molar ratio of the aromatic dicarboxylic acid or its derivative as a raw material to glycols is 1:
A raw material in the range of 1.2 to 1: 3.0 is supplied, the temperature is set to 220 to 275 degrees, the raw material is reacted, and an oligoester having an average polymerization degree of 3 to 7 or less as a product. Or a first reactor in which polyester is produced;
The product supplied from the first reactor is supplied, the temperature is set to 220 to 280 ° C., the pressure is set in the range of atmospheric pressure to 133 Pa, the product is reacted, and the average degree of polymerization is 20 to 40. A second reactor in which a low polymer is produced;
The low polymer supplied from the second reactor is supplied, and the low polymer is reacted at a temperature of 220 to 280 ° C. and a pressure in the range of 220 to 13.3 Pa. An apparatus for continuously producing polybutylene terephthalate comprising a third reactor for producing polybutylene terephthalate by polycondensation up to 180 degrees,
Polybutylene having a stirring rotor in which the third reactor rotates, the stirring rotor having a plurality of stirring blade blocks corresponding to the viscosity of the treatment liquid, and having no rotating shaft at the center of the stirring blade Continuous production equipment for terephthalate. A continuous production apparatus for polybutylene terephthalate according to claim 5,
The third reactor has an inlet and an outlet for the liquid to be treated at the lower end and the lower end in the longitudinal direction of the horizontal cylindrical container body, respectively.
An apparatus for continuously producing polybutylene terephthalate having a volatiles outlet at the top of the main body. An apparatus for continuously producing polybutylene terephthalate according to claim 5 or 6,
An apparatus for continuously producing polybutylene terephthalate, wherein the rotation speed range of the stirring blade of the third reactor is 0.5 to 10 rpm. A continuous production apparatus for polybutylene terephthalate according to any one of claims 5 to 7,
An apparatus for continuously producing polybutylene terephthalate, wherein the total reaction time of the first reactor, the second reactor, and the third reactor is operated between 4 and 9 hours.

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