JPS6222826A - Batchwise polyester polymerization tank - Google Patents

Abstract

PURPOSE:To obtain a uniform polyester under stable conditions, by providing a batchwise polyester polymerization tank with a pipe for recirculating a polyester polymerization solution and a specified plate-type sparger blade. CONSTITUTION:A prepolymerization solution of a polyester is fed to a vessel 1 through a feed inlet 5; the reaction solution is recirculated through a die 9, a pump 11, a pipe 13 and an inlet 6 to the body of the vessel 1 by starting the pump 11 almost simultaneously with the start of the drive of a rotary shaft 14; and the reaction solution is brought into a state in which the upper inside wall of the body 1 is coated therewith and is allowed to flow downwardly along the inside wall of the body 1 by rotating a plate-type sparger blade 18 rotating near the top inside wall of the body 1. At the same time, part of the solution is allowed to fall in the form of a thin film from the top wall surface, sparger blade 18, etc. The recirculation of the reaction solution is performed during the period of from the time when the reaction solution is fed to the body 1 and to the time when the polymerization is completed, during the period from the time when the number-average degree of polymerization is about 10 to the time when the polymerization is completed or, especially, during the latter stage of the polymerization period.

Description

[Detailed description of the invention] <Industrial application field> The present invention is a batch type polyester manufacturing apparatus.

A cylinder that is especially suitable for operating under certain stable conditions and producing uniform polyester! This relates to a type of batch-type polymerization reaction cypress.

<Prior art> Polyester is generally a difunctional carboxylic acid glycol ester and/or its low polymer, for example, in the case of polyethylene terephthalate, it is generated by heating terephthalic acid ethylene glycol ester and/or its low polymer under reduced pressure. It is produced by removing glycol from the system.

What is important during this polymerization reaction is to quickly remove the generated glycol from the system, so the reaction is carried out at high temperature and under reduced pressure, and is carried out on a device that is designed to maximize the surface area of the reactants. Improvements are being considered.

On the other hand, in order to quickly remove the generated glycol from the system, it is considered advantageous to promote the polymerization reaction by renewing the surface of the reactant to promote the diffusion of the generated glycol and to make the reactant uniform.

From this point of view, many proposals have been made to improve the shape and position of the stirring blades (for example, Japanese Patent Laid-Open No. 51-4520
No. 0, JP-A-51-126295,! #Kokai No. 52-12296).

However, such conventional techniques are still not sufficient, and there is a desire to develop even more effective devices.

<Objective of the Invention> The present invention was made in view of the current situation, and an object of the present invention is to propose an apparatus that can effectively renew the surface of a reaction solution and quickly remove generated glycol from the system. It is something.

<Structure of the Invention> That is, 1. The present invention is a vertical batch-type polyester polymerization reaction tank equipped with a vertical rotating shaft having an internal pressure stirring blade in a cylindrical container, in which a force is applied to the reaction tank from the bottom to the top of the container via a pump. In addition, a plurality of plate-shaped dispersion blades are provided below the inlet for the circulating reaction liquid and close to the top of the container to apply the reaction liquid to the side wall surface of the container. This is a batch-type polyester polymerization reaction tank specially designed to be installed on a rotating shaft.

<Example> The present invention will be explained below based on the drawings. The figure is a schematic sectional view showing an embodiment of the present invention.

In the figure, 1 is the main body of the polymerization tank, and its outside is covered with an outer wall plate 2, forming a heating jacket 3 using a heat medium.The top of the main body 1 has a vacuum suction port 4. Port 5. Inlet port 6 (multiple ports may be provided) for circulating fluid is provided,
A discharge pulp 8 and a slit-shaped discharge die 9 are attached to the lower part via a discharge lower. A partition plate is attached to the lower end discharge port 9' of the die 9, which is kept closed except during discharge. A circulating fluid outlet 10 is provided at the bottom of the die 9, and is connected to the suction side of a pump 11 installed outside via a pipe 12, and a pipe communicating with the inlet 6 is provided on the delivery side of the pump 11. 13 are connected to form a circulation system for the reaction solution. These circulation systems are also heated to a predetermined temperature by heating means.

Note that the outlet 10 is not limited to the tie 9, but also the lower part K11f of the main body.
You can also set up a connection. There is an anchor type stirring 1I inside the main body 1.
A vertical rotation shaft 14 is provided with a shaft t15 attached at the lower part. This stirring! For example, 15 is usually 5 to l 00 r,
It is rotated at a rotation speed of p and m, but it is not limited to this, and its shape is limited to an anchor type and a helical shape as long as it can easily renew the surface of the reaction liquid.

Any shape such as a cage can be used. 16 is a bearing part, 17
is a driving motor. Reference numeral 18 denotes an anchor-type dispersion vane installed below the inlet 6 and close to the upper inner wall surface of the main body 1 so as to wrap around the inner wall surface. A plurality of plates are arranged at approximately equal intervals and fixed to the rotating shaft 14. An anchor type is usually used as the dispersion@18, but it is possible to scatter the falling liquid or Any shape can be used as long as the shape is such that the dispersing blades 18 can be dispersed in the stirring blade 15.
It is also possible to provide it integrally with

In such an apparatus, when a predetermined amount of polyester initial polymerization reaction solution is supplied from the charging port 5, the pump 11 is operated before and after the rotating shaft 14 is driven to circulate the reaction solution.

That is, the reaction liquid flows from the die 9 to the tube 12. Pump 11. tube 1
3 and returns to the container main body IK from the inlet 6, but in this case, the reaction liquid introduced from the inlet 6 stagnates in a position close to the upper inner wall surface of the container main body and is circulated by the rotating dispersion blade 18. As a result of the action, it is dispersed and dispersed upwardly and laterally, so that it is coated on the upper and lateral inner wall surfaces of the main body 1, and flows down in a swamp on the wall surface.

In addition, a part of it falls from the upper wall surface, the dispersion blade 18, etc. in the form of a thin film. Therefore, the surface of the reaction liquid can be renewed very effectively.

Circulation of the reaction solution is normally carried out after the polymerization reaction is completed after it is charged into the container body 1, but it is carried out in the late polymerization region from when the number average degree of polymerization is about 10 to the completion of the polymerization reaction. is preferable.

Next, to explain more specifically, dimethyltereph clay)
A mixture of 1200 kli+, 720 kg of ethylene glycol, and 0.72 kg of acetic acid was heated to 140 to 240° C. over 3 hours to distill off methanol and perform a transesterification reaction. This reaction product contains 0.0% phosphorous acid.
After 42 hours, 0.49 kg of antimony dioxide was added to the mixture, and the mixture was heated to 250° C. for 15 minutes under normal pressure to distill off excess Glyfur.

The obtained transesterification reaction product having a number average degree of polymerization of 2 to 5 was transferred to a polymerization reactor aC having upper and lower blades as shown in the figure, inner diameter 130 cm + stirring blade diameter 120 cm + dispersion R4.
The spacing between the 9 blades (equally spaced) and the upper inner wall surface is 10 x
Transfer the reaction solution to 20 m) under stirring (2Or, p, m).
While circulating at 0.01/MM, the temperature was increased and the pressure was gradually reduced to a reaction temperature of 285° C., and a polycondensation reaction was carried out for 90 minutes. [η] of the obtained polymer was 0.65.

For comparison, a similar reaction was carried out in a polymerization apparatus without a dispersion blade and a reaction liquid circulation system (otherwise the same), and the obtained polymer had an [η] of 0.45).

Incidentally, here, parts are i parts, and [η] is the intrinsic viscosity determined from the viscosity measured at 35° C. in an orne chlorophenol solution.

<Effects of the Invention> As explained above, according to the present invention, the polycondensation reaction of polyester can be carried out quickly, and the quality of the obtained polymer can be improved, so the industrial significance thereof is extremely large. There is one.

[Brief explanation of the drawing]

The figure is a schematic cross-sectional view showing an embodiment of the present invention. 1... Container body, 6... Inlet. 9...Discharge die, 10...Guiding port. 11...Pump, 12.13...Pipe. 14... Rotating shaft, 15... Stirring blade. 】8...dispersion

Claims (1)

[Claims] In a vertical batch type polyester polymerization reaction tank equipped with a vertical rotating shaft having stirring blades in a cylindrical container, a pipe line for forcibly circulating a reaction liquid from the bottom of the reaction tank to the top of the container via a pump. is provided, and a plurality of plate-shaped dispersion vanes are attached to the rotating shaft to apply the reaction liquid to the top of the container and the side wall surface at a position below the inlet for the circulating reaction liquid and close to the top of the container. Batch-type polyester polymerization reactor