JP2000007773A - Apparatus and method for continuous manufacture of polycondensation polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide apparatus and method for continuously manufacturing a polycondensation polymer, wherein fluids to be treated are, respectively, retained in individual reactors only within necessary residence times and are successively transferred for reaction, by arranging the bottom of an initial polymerization vessel at a level higher than the bottom position of a final polymerization vessel, and operating a flow rate control valve, attached between the polymerization vessels, by an output from a liquid level detecting means within the initial polymerization vessel. SOLUTION: This apparatus is favorable for the treatment of a highly viscous fluid, particularly for polycondensation of polyethylene terephthalate or the like operated under reduced pressure. An initial polymerization vessel 2 is set at a level of its bottom higher by H1 than the bottom position of a final polymerizer 3. Starting materials, such as ethylene glycol, terephthalic acid and the like, are heated in an esterification vessel 1, and the resultant oligomer, from which water and the like formed during the reaction have been removed, is fed to the initial polymerization vessel 2 by means of a first gear pump 4. The polymer of a low degree of polymerization obtained after the initial polymerization is passed into the final polymerizer 3 through a flow rate control valve 6, and a polymer with a predetermined degree of polymerization is withdrawn by means of a second gear pump. The liquid level within the initial polymerization vessel 2 is detected by means of a level meter, and the apparatus is operated while keeping the liquid level at a preset position by operating the opening of the flow rate control valve 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for continuously treating a high-viscosity liquid, and more particularly to an apparatus and a method suitable for polycondensation of polyethylene terephthalate or the like operated under reduced pressure.

2. Description of the Related Art Conventionally, as a continuous polycondensation apparatus for polyethylene terephthalate or the like, as shown in JP-A-8-3301, means for transport such as a gear pump between respective reactors from an esterification tank to a final polymerization tank. Was attached, and the liquid to be treated was sequentially moved to perform polycondensation.

However, there is room for improvement in the above prior art, such as simplification of transportation means such as a gear pump. An object of the present invention is to improve the above-mentioned conventional technology, and to provide a continuous production apparatus and method in which a liquid to be treated is retained in each reactor for a required residence time with a relatively simple structure, and is sequentially moved and reacted. It is in.

The object of the present invention is to increase the height of the bottom of the initial polymerization tank from the bottom position of the final polymerization tank, attach a flow control valve between the initial polymerization tank and the final polymerization tank, By the output from the liquid level detecting means of the liquid to be treated in the polymerization tank,
This is achieved by a structure that operates the flow control valve. As a result, the liquid to be treated stays in the initial polymerization tank only for the residence time necessary for the reaction, becomes a prepolymer having a predetermined polymerization degree, and can be continuously sent to the final polymerization tank.

FIG. 1 shows an embodiment of the present invention.
In the figure, 1 is an esterification tank, 2 is an initial polymerization tank, 3 is a final polymerization machine, 4 is a first gear pump for transferring the esterified oligomer, and 5 is a second gear pump for extracting the polymer. Reference numeral 6 denotes a flow control valve attached between the initial polymerization tank and the final polymerization tank, which is connected to a liquid level gauge 7 for the liquid to be treated in the initial polymerization tank. Reference numeral 8 denotes a distillation column connected to the top of the esterification tank 1, and reference numerals 9 and 10 denote condensers connected to the tops of the initial polymerization tank 2 and the final polymerization machine 3, respectively. Here, the initial polymerization tank 2 is installed so that the height of the bottom is higher than the bottom position of the final polymerization tank 3 (H1, FIG. 1). In a further preferred embodiment, the liquid level of the liquid to be treated on the outlet side of the initial polymerization tank is higher than the liquid level of the liquid to be treated on the inlet side of the final polymerization tank (FIG. 1, H2). The amount of liquid retained in each tank is set. In such an apparatus, a raw material slurry (eg, EG, terephthalic acid, etc.) is heated in the esterification tank 1 and a distillate (eg, water) generated by the reaction.
And is sent to the initial polymerization tank 2 by the first gear pump 4. Then, the low polymerization degree polymer having undergone the initial polymerization enters the final polymerization tank 3 through the flow control valve 6, becomes a polymer having a predetermined polymerization degree, and is extracted by the second gear pump 5. Here, the liquid level of the liquid to be treated in the initial polymerization tank 2 is detected by a liquid level gauge 7, and is operated at a predetermined position by operating the opening of the flow control valve 6.
As a result, the liquid to be treated stays in the initial polymerization tank 2 only for the residence time necessary for the reaction, becomes a prepolymer having a predetermined polymerization degree, and is continuously sent to the final polymerization tank 3. When polyethylene terephthalate is continuously produced by such an apparatus, the slurry of the raw material (a mixture of EG and terephthalic acid) is heated in the esterification tank 1 to remove the distillate produced by the reaction, and the oligomer (bishydroxyethyl) is removed. Terephthalate)
And supplied to the initial polymerization tank 2 by the gear pump 4. The liquid to be treated is supplied to the flow control valve 6 at the outlet of the initial polymerization tank 2.
Thus, the prepolymer having a predetermined degree of polymerization stays only for the residence time necessary for the reaction, and is continuously sent to the final polymerization tank 3. Here, the degree of polymerization further increases and becomes a polymer having a predetermined degree of polymerization, and is extracted by the second gear pump 5. At this time, the pressure in the initial polymerization tank 2 is 0.6 to 4 k.
Pressure of final polymerization tank 3 in Pa, 0.04 to 0.5 kPa
The liquid level on the outlet side in the initial polymerization tank 2 is higher than that in the final polymerization tank 3
Since the operation is performed at a position higher than the liquid level on the inner inlet side, the amount of residence in the initial polymerization tank 2 can be stably maintained at a predetermined value by adjusting the opening of the flow control valve 6. When polyethylene nalephthalate is continuously produced by the present apparatus, a slurry of a raw material (a mixture of EG and naphthalenedicarboxylic acid dimethyl ester) is supplied to a transesterification tank instead of the esterification tank 1 in FIG. Remove distillate to make oligomer. The oligomer is supplied to the initial polymerization tank 2 by the gear pump 4, the level of the liquid to be treated at the outlet side of the initial polymerization tank is detected, and the flow control valve is operated to remove the low polymerization degree polymer after the initial polymerization. It is supplied to the final polymerization tank 3 to obtain a final polymerization product. When polycarbonate is continuously produced by this apparatus, the slurry of the raw material (mixture of bisphenol A and diphenyl carbonate) is heated in a transesterification tank, and the distillate (phenol, etc.) generated by the reaction is removed to remove oligomers. Is supplied to the initial polymerization tank 2 by the gear pump 4, the level of the liquid to be treated at the outlet side of the initial polymerization tank is detected, the flow control valve is operated, and the low-polymerized polymer having undergone the initial polymerization is finally polymerized. It is supplied to the tank 3 to obtain a final polymer. Similarly, the present invention can be applied to continuous polymerization of a polycondensation polymer such as polyamide. According to the preferred embodiment of the present invention, a second flow control valve 16 is installed between the esterification tank 1 and the initial polymerization tank 2 as shown in FIG. By the output from the liquid level detecting means 17, the second
There is a structure in which the flow control valve 16 is operated. According to the present embodiment, the continuous operation can be performed without using the gear pump 4 or the like, by using the flow control valve 16 having a relatively simple structure to keep the retention amount of the liquid to be treated in the esterification tank 1 at a predetermined amount.

According to the present invention, the liquid to be treated can be held in each reactor for a required residence time with a relatively simple structure, and can be sequentially moved and reacted.

[Brief description of the drawings]

FIG. 1 is an overall flowchart showing one embodiment of the present invention.

FIG. 2 is an overall flowchart showing another embodiment of the present invention.

[Explanation of symbols]

1 ... esterification tank, 2 ... initial polymerization tank, 3 ... final polymerization machine,
4 ... first gear pump, 5 ... second gear pump, 6 ... flow control valve, 7 ... submerged liquid level meter.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Susumu Harada, Inventor 794, Higashi-Toyoi, Kazamatsu, Kamamatsu City, Yamaguchi Prefecture Inside the Kasado Plant of Hitachi, Ltd. (72) Yasunari Sase, 794, Higashi Toyoi, Kudamatsu, Yamaguchi Prefecture, Japan (72) Inventor Hiroo Suzuki 794, Higashi-Toyoi, Kazamatsu, Kudamatsu City, Yamaguchi Prefecture F-term (reference) 4J029 AA03 AA10 AB04 AC01 BA03 BB13A CB06A CC05A HA01 HB01 HC03 KE05 LA02 LA06 LA10 LA14 LB04 LB09

Claims (6)

[Claims] In a continuous production apparatus in which an esterification tank, an initial polymerization tank and a final polymerization tank are connected in series, the height of the bottom of the initial polymerization tank is made higher than the bottom position of the final polymerization tank. Attach a flow control valve between the polymerization tank and the output from the liquid level detection means of the liquid to be treated in the initial polymerization tank,
A continuous production system for polycondensation polymers with a structure that operates a flow control valve. 2. The continuous production apparatus for a polycondensation polymer according to claim 1, wherein the liquid level of the liquid to be treated at the outlet of the initial polymerization tank is adjusted to the liquid level of the liquid to be treated at the inlet of the final polymerization tank. Continuous production equipment for polycondensation polymers whose height is higher than the surface height. 3. The continuous production apparatus for a polycondensation polymer according to claim 1, wherein a second polymer is provided between the esterification tank and the initial polymerization tank.
A continuous production apparatus for a polycondensation polymer, having a structure in which a flow rate control valve is attached and a second flow rate control valve is operated by an output from a liquid level detecting means of the liquid to be treated in the esterification tank. 4. An apparatus according to claim 1, wherein a mixed slurry of terephthalic acid and ethylene glycol is continuously supplied to an esterification tank, the esterified oligomer is supplied to an initial polymerization tank, and a coating on the outlet side of the initial polymerization tank is supplied. A continuous polycondensation method for polyethylene terephthalate, in which the level of the treatment liquid is detected, the flow control valve is operated, and the low-polymerized polymer having undergone the initial polymerization is supplied to the final polymerization tank to obtain the final polymer. 5. A mixed solution of naphthalenedicarboxylic acid dimethyl ester and ethylene glycol is continuously supplied to a transesterification tank, an oligomer produced by the reaction is supplied to an initial polymerization tank, and a liquid to be treated at the outlet side of the initial polymerization tank is supplied. A continuous polycondensation method for polyethylene naphthalate, in which the liquid level is detected, the flow control valve is operated, and the low-polymerized polymer having undergone the initial polymerization is supplied to the final polymerization tank to obtain the final polymer. 6. A mixed solution of bisphenol A and diphenyl carbonate is continuously supplied to a transesterification tank, an oligomer produced by the reaction is supplied to an initial polymerization tank, and a liquid level of a liquid to be treated at an outlet side of the initial polymerization tank is provided. A continuous polycondensation method for polycarbonate in which a height is detected, a flow control valve is operated, and a low-polymerized polymer having undergone initial polymerization is supplied to a final polymerization tank to obtain a final polymer.