JPH08311207A - Apparatus and method for continuously producing polycondensation polymer - Google Patents

Abstract

PURPOSE: To make it possible to decrease the number of reactors and the total number of parts, to reduce the man-power for assemblage and piping and to reduce the cost of installation of heat insulation materials by integrating a transesterification tank with a prepolymerization tank by vertically arranging them in series. CONSTITUTION: Materials 13 used for a polycondensation polymer and heated with an external heat exchanger 17 are fed from an inlet nozzle 5 into the upper transesterification tank 2 and transesterified under agitation while a recirculation solution 18 is being recirculated through a recirculation nozzle formed on the upper part and a pump 6, and the formed by-product is discharged from a discharge nozzle 11. On the other hand, the product of transesterification is passed through a connecting pipe 7 attached on the surface of the treated solution, and a flow rate control valve 9, fed into a prepolymerization tank 3, and allowed to flow downwardly along a ring-like tray 8a, a cylindrical tray 8b and a ring-like tray 8c to prepolymerize the materials to a desired degree of polymerization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for producing polymer resins, and more particularly to an apparatus and method suitable for polymerizing polycondensation polymers such as polyethylene terephthalate and polycarbonate.

[0002]

2. Description of the Related Art Conventional polyethylene terephthalate (PE
As the polymerization method of T), a manufacturing process including a transesterification tank, an initial polymerization tank, and a polymerization tank is used as described in Process Compilation (1970) P892 edited by Japan Chemical Engineering Association. In an actual process, it is general that the transesterification tank is divided into several units, and the initial polymerization tank is also divided into two and used.

[0003]

However, due to the recent yen appreciation and the decrease in resin prices due to the entry of developing countries, there is an active demand for lowering the cost of resin production equipment.
To address this, we are trying to achieve it by simplifying the process.

An object of the present invention is to reduce the number of reaction tanks by integrating a transesterification tank and an initial polymerization tank so as to reduce the total number of driving parts, piping points, sealing parts, etc. of each stirring tank. Is

[0005]

[Means for Solving the Problems] The above problems and objectives are to install a transesterification tank in the upper tower and install an initial polymerization tank in the lower tower to integrate them, and reduce the number of constituent parts and materials of the manufacturing apparatus.
This is achieved by reducing the number of man-hours for assembling piping for the device and reducing the heat insulation and installation cost.

[0006]

[Function] The raw material continuously supplied from the inlet nozzle undergoes transesterification in the upper tower, then produces oligomers, is supplied to the lower tower, and is supplied to the lower tower while vaporizing volatiles in each stirring chamber inside the lower tower. Flow to the side, the polycondensation reaction proceeds efficiently, and the degree of polymerization is increased.

[0007]

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is a vertically long cylindrical container body whose outer periphery is covered with a heat medium jacket (not shown), the container body is divided into two inside, and the upper column side is a transesterification tank 2 and the lower column side. The initial polymerization tank 3 is formed. The raw material 13 enters from a supply nozzle 4 provided at the bottom of the transesterification tank 2. At this time, the raw material 13 is heated to the transesterification reaction temperature by the external heat exchange 17 and supplied. The supply nozzle 4 has a circulating liquid 18 circulated by a circulation pump 6 from a circulation nozzle 16 at the upper part of the upper tower.
Is combined with the raw material 13 and supplied. The treatment liquid in the upper tower is agitated and mixed by the circulation action of the circulation pump 6,
The esterification reaction is promoted. A nozzle 11 for removing a by-product 12 produced by a transesterification reaction is attached to the upper part of the transesterification tank 2, and is separated and recovered by a condenser on the downstream side. The transesterification tank 2 and the initial polymerization tank 3 are connected by a connecting pipe 7. The upper end side of the transesterification tank 2 is raised to the liquid surface above the transesterification tank 2, and the lower end side thereof is provided inside the initial polymerization tank 3. Tray 8
It is installed in the liquid pool of a, and a flow rate adjusting valve 9 for adjusting the liquid level of the tray 8a is provided in the middle of the connecting pipe 7 so that the liquid level on the tray 8a has a predetermined height. Is controlled to be. That is, the opening / closing degree of the flow rate adjusting valve 9 is controlled according to the increase / decrease in the liquid level of the tray 8a, and the increase / decrease in the liquid level is suppressed. The vapor phase portion of the initial polymerization tank 3 is provided with a volatile matter extraction nozzle 10 for removing the volatile matter 14 generated by the polymerization reaction from the liquid surface of each tray and evaporated. A vacuum pump (not shown) for collecting the pressure in the tank and a condenser (not shown) for collecting by-products are provided on the downstream side of the volatile matter extraction nozzle 10. As shown in the figure, in this embodiment, the initial polymerization tank 3 has no stirring blade member inside. Instead of this agitating blade, downflow trays are installed in multiple stages to obtain a large surface renewal action. Inside the initial polymerization tank 3, ring-shaped trays 8a and cylindrical trays 8b are alternately arranged.
Inner peripheral upper surface side of ring-shaped tray 8a and cylindrical tray 8
One or a plurality of notches are provided on the outer peripheral upper surface side of b, and the processing liquid flows to the tray on the downstream side and reaches the bottom of the initial polymerization tank 3, and the initial polymerization product is discharged from the extraction nozzle 5. 15 is taken out and proceeds to the next polymerization tank (not shown) to further increase the degree of polymerization.

A case of producing polyethylene terephthalate with the above-mentioned structure will be described. As a raw material of polyethylene terephthalate, a mixture of terephthalic acid and ethylene glycol or a mixture of dimethyl terephthalate and ethylene glycol is generally used. These raw materials 13 are heated via the external heat exchanger 17 and supplied from the inlet nozzle 4 to the transesterification tank 2. In the transesterification tank, the circulating liquid 16 is circulated by the pump 6 from the circulation nozzle 16 provided at the upper part to uniformly stir the inside of the tank. The temperature in the tank is 240 ° C. to 260 ° C., and the transesterification reaction is carried out under atmospheric pressure or under pressure. By-products (water and ethylene glycol or methanol and ethylene glycol) produced by the transesterification reaction are collected by a by-product collection condenser (not shown) installed upstream of the by-product removal nozzle 11. On the other hand, bisbetahydroxyethyl terephthalate produced by transesterification is supplied from the upper end of the connecting pipe 7 provided on the surface of the treatment liquid to the upper tray on the lower tower side. At this time, the operating pressure of the lower tower is 1
Since the pressure is 3000 Pa to 133 Pa, the flow rate is adjusted by the flow rate adjusting valve 9 provided in the middle of the connecting pipe 7 so that the liquid height of the tray 8a is always constant. The processing liquid is transferred from the uppermost ring-shaped tray 8a to the cylindrical tray 8b.
Further, it flows down sequentially to the ring-shaped tray 8a. At this time, since the treatment liquid is in a reduced pressure atmosphere, a by-product generated by the polymerization reaction is vaporized and vigorous foaming occurs. As a result, the treatment liquid is mixed and at the same time strongly receives a surface renewal action to accelerate the polymerization reaction. Will be done. By providing such a tray structure in a plurality of stages, the residence time necessary for the reaction can be secured and the desired degree of polymerization can be obtained. In some cases, it may be further connected to an intermediate polymerization machine, a final polymerization machine or the like to further increase the degree of polymerization before use.

Next, another embodiment of the present invention will be described with reference to FIG. In the figure, the configuration and operation are the same as those of the transesterification tank of the embodiment of the present invention shown in FIG. The initial polymerization tank 3 of the present invention is connected to the transesterification tank 2 of the upper tower by a connecting pipe 7, and a flow rate adjusting valve 9 is provided therebetween so that the liquid level on the liquid tray 24 provided at the upper part of the lower tower is at a predetermined height. Is controlled to be. The liquid tray has a ring shape with a space in the center and is configured to have the same atmosphere as the downstream side. On the downstream side thereof, stirring chambers 20 forming a ring-shaped liquid pool are installed in multiple stages, and a stirring member 22 for thoroughly stirring the inside of the stirring chamber 20 is provided for each stirring chamber, and the center of the initial polymerization chamber is provided. It is connected to a stirring shaft 23 installed in the section. Further, each stirring chamber 20 is provided with a connecting pipe 21 that connects the upper side liquid surface of each upper tray and the bottom side surface portion of the stirring chamber, so that the processing liquid always flows out from the liquid surface of the stirring chamber, The flow is supplied from the bottom side of the.

The case of producing polyethylene terephthalate with the above constitution will be described. As a raw material of polyethylene terephthalate, a mixture of terephthalic acid and ethylene glycol or a mixture of dimethyl terephthalate and ethylene glycol is generally used. These raw materials 13 are heated via the external heat exchanger 17 and supplied from the inlet nozzle 4 to the transesterification tank 2. In the transesterification tank, the circulating liquid 16 is circulated by the pump 6 from the circulation nozzle 16 provided at the upper part to uniformly stir the inside of the tank. The temperature in the tank is 240 ° C. to 260 ° C., and the transesterification reaction is carried out under atmospheric pressure or under pressure. By-products (water and ethylene glycol or methanol and ethylene glycol) produced by the transesterification reaction are collected by a by-product collection condenser (not shown) installed upstream of the by-product removal nozzle 11. On the other hand, bisbetahydroxyethyl terephthalate produced by transesterification is supplied from the upper end of the connecting pipe 7 provided on the surface of the treatment liquid to the upper tray on the lower tower side. At this time, the operating pressure of the lower tower is 1
Since the pressure is 3000 Pa to 133 Pa, the flow rate is adjusted by the flow rate adjusting valve 9 provided in the middle of the connecting pipe 7 so that the liquid height of the tray 24 is always constant. The treatment liquid on the uppermost tray flows to the stirring chamber 20 immediately downstream through the connecting pipe 21. The treatment liquid supplied to the stirring chamber 20 is stirred by the stirring member 22 to accelerate the polymerization reaction. In addition, the stirring action by the stirring blade activates the surface renewal action, and the reaction proceeds further. The reaction by-product generated at this time is removed from the volatile matter extraction nozzle 10 for removing the volatile matter 14. The treatment liquid after the lapse of a predetermined residence time in the initial polymerization tank is collected in the lower portion of the tank, the initial polymerization product 15 is taken out from the withdrawing nozzle 5, and further advances to the next polymerization tank (not shown) as necessary. The degree is increased.

[0011]

According to the present invention, since the transesterification tank and the initial polymerization tank are integrally formed, the cost of the polycondensation resin manufacturing apparatus can be reduced, and the installation space of the apparatus is small. There is an advantage.

[Brief description of drawings]

FIG. 1 is a device configuration diagram showing an embodiment of the present invention.

FIG. 2 is a device configuration diagram showing another embodiment of the present invention.

[Explanation of symbols]

1 ... Container body, 2 ... Transesterification tank, 3 ... Initial polymerization tank,
4 ... Supply nozzle, 5 ... Extraction nozzle, 6 ... Circulation pump, 7 ... Connection pipe, 8a ... Ring tray, 8b ... Cylindrical tray, 9 ... Flow control valve, 10 ... Volatile substance ejection nozzle, 11 ... By-product removal Nozzle, 12 ... By-product, 13 ...
Raw material, 14 ... Volatile matter, 15 ... Prepolymer, 16 ... Circulation nozzle, 17 ... External heat exchange, 18 ... Circulating liquid, 20 ... Stirring chamber,
21 ... Connection pipe, 22 ... Stirring blade, 23 ... Stirring shaft, 24 ... Tray.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Kinoshita 794 Azuma Higashitoyo, Shimomatsu City, Yamaguchi Prefecture Inside the Kasado Plant, Hitachi, Ltd. Hitachi Co., Ltd. Kasado Factory

Claims (7)

[Claims] 1. A production apparatus for continuously producing a polycondensation polymer, wherein a polycondensation reaction is carried out between an oligomer and a transesterification tank for producing an oligomer by a transesterification reaction from a mixture of raw materials to produce an intermediate polymer. The initial polymerization tanks are vertically arranged in series, and the transesterification tower of the upper tower and the initial polymerization tower of the lower tower are combined to form an integrated structure, and the raw material inlet of the upper tower is the bottom of the upper tower. Installed on the side of the upper tower, the connecting pipe between the upper tower and the lower tower is raised to the upper liquid surface on the upper tower side, and the end of the connecting pipe on the lower tower side is installed in the liquid in the liquid pool provided on the upper part of the lower tower. An outlet for the processing liquid is provided at the bottom of the column, and a flow rate adjustment valve is provided in the connecting pipe that connects the upper tower and the lower tower. Even if there is a pressure difference between the upper tower and the lower tower, this flow control valve can control the flow rate to a specified value However, the upper tower is equipped with an external circulation type stirring mechanism for uniformly mixing the inside of the tank. Only, continuous production apparatus polycondensation polymer, which comprises placing a tray having a liquid reservoir of the plurality of stages without installing a stirring blade in the lower column. 2. The continuous production apparatus according to claim 1, wherein the plurality of trays installed in the lower tower have a diameter larger than the diameter of the ring-shaped tray having an L-shaped cross section and the ring-shaped hollow portion. A continuous polycondensation polymer production apparatus, characterized in that a plurality of trays having a shape are alternately installed. 3. The continuous manufacturing apparatus according to claim 2, wherein the L-shaped ring-shaped tray installed in the lower tower is provided with a part or a plurality of notches on the inner diameter side and the outer diameter side of the circular tray, respectively. An apparatus for continuously producing a polycondensation polymer, characterized in that the treatment liquid in the inside is made to flow down. 4. The continuous production apparatus according to claim 1, wherein the upper tower is provided with an external circulation type stirring mechanism for uniformly mixing the inside of the tank, and the lower tower is provided with a plurality of stages in the longitudinal direction inside the main body. A ring-shaped member having an L-shaped cross-section is divided to form a stirring chamber having a space in the center, and the stirring member that stirs each stirring chamber thoroughly is attached to a stirring shaft provided in the center of the lower tower. An apparatus for continuously producing a polycondensation polymer, characterized by: 5. The continuous production apparatus according to claim 4, wherein a connecting pipe for connecting the upper and lower stirring chambers provided in the lower tower is the liquid surface side on the upper stirring chamber side, and the stirring chamber bottom is on the lower stirring chamber side. An apparatus for continuously producing a polycondensation polymer, which has a structure of connecting to a polycondensation polymer. 6. A raw material for a polycondensation polymer is supplied by the continuous production apparatus according to any one of claims 1, 2, 3, 4 and 5, and a transesterification reaction is carried out in the upper column at about atmospheric pressure. A continuous polycondensation method in which an oligomer is generated and a polycondensation reaction operation is performed in a reduced pressure atmosphere in a lower tower to obtain an initial polymerization reaction product or an intermediate polymerization reaction product having a low to medium polymerization degree. 7. A continuous production apparatus according to any one of claims 1, 2, 3, 4 and 5 is used to supply a mixture of terephthal and ethylene glycol or a mixture of dimethyl terephthalate and ethylene glycol, and the temperature is 240 ° C. in the upper column.
To 270 ° C., the pressure is at atmospheric pressure or under pressure to perform a transesterification reaction to produce bisbetahydroxyethyl terephthalate, which is flowed down to the lower column at a temperature of 270 ° C. to 290 ° C. and a pressure of 13000 Pa to 133 Pa. A continuous polycondensation method of polyethylene terephthalate that evaporates volatile substances such as ethylene glycol and moves them to a stirring chamber on the downstream side to increase the degree of polymerization.