JPH1077348A - Apparatus and method for continuous polycondensation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for continuous polycondensation that carry out highly efficient reaction to produce quality polymers by maintaining the liquid to be processed in thin-film condition with agitator blades of relatively simple structure inside the body of the apparatus while refreshing the liquid surface, and are applicable to a wide range of viscosity of the liquid with small power consumption for the agitation. SOLUTION: This apparatus for continuous polycondesation comprises a horizontal cylindrical vessel body 1, an agitator rotor 4 which revolves along and close to the inside surface of the vessel body in the longitudinal direction and inside which a plurality of agitator blocks in the optimum number corresponding to the viscosity range of the process liquid are provided, rotary bearing shafts (3a, 3b) fitted to both ends of the agitator rotor via a bearing member without such members as center shaft along the revolution center of the agitator rotor. The liquid inside the body 1 is thin-filmed by the agitator blocks in the optimum number corresponding to the viscosity range of the process liquid so that a wide evaporation area can be secured, thereby retaining sufficient surface renewing action to enable efficient production of quality polymers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for stirring a highly viscous substance, and more particularly to a method for stirring a polyethylene terephthalate.
TECHNICAL FIELD The present invention relates to an apparatus and a method suitable for a continuous polymerization reaction of polycondensation polymers such as glass and polycarbonate.

[0002]

2. Description of the Related Art Conventionally, as a horizontal continuous processing apparatus for polycondensation polymers such as polyethylene terephthalate, Japanese Patent Publication No.
As shown in JP-A-1228, there is a method in which a liquid to be treated is scooped up by a ring-shaped disk and a scraping plate, dropped on a perforated plate or a wire mesh to form a thin film, and volatile substances are evaporated to cause a reaction.

[0003]

However, the prior art described above evaporates volatiles while dropping on a perforated plate or a wire mesh in the direction of gravity, and sufficient attention has been paid to maintaining the state of a thin film for a long time. There was room for improvement. Further, since the structure of the stirring blade has the same structure from the inlet to the outlet of the processing liquid, there is a problem that the range of viscosity that can be processed is limited.

An object of the present invention is to improve the above prior art,
A relatively simple structure of the stirring blade allows the liquid to be treated in the main body to be kept in a thin film state for a long time to perform good surface renewal. It is an object of the present invention to provide a continuous polycondensation apparatus and a continuous polycondensation method for efficiently reacting a high-quality polymer having a wide range.

[0005]

The above object is achieved by a stirring blade which connects a stirring rotor to a plurality of stirring blocks optimal for the viscosity of each processing solution.

[0006]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a front view showing a longitudinal section of the device of the present invention. In the figure, reference numeral 1 denotes a horizontally long cylindrical container body whose outer periphery is covered with a heat medium jacket (not shown), and shafts 3a and 3b for rotation support are attached to both ends in the longitudinal direction. A stirring rotor 4 is mounted between the rotation supporting shafts 3a and 3b, and one of the rotation shafts 3a is connected to a driving device (not shown). The stirring rotor 4 has strength members 5a, 5
b, 5c, and 5d (in this embodiment, four rotors are shown, but the number of rotors used is determined by the size of the rotor). The stirring rotor 4 composed of a stirring block is formed. The stirring rotor 4 has a low-viscosity block on the inlet nozzle 11 side composed of a bucket portion constituted by scraping plates 6a and 6b, a thin disk 7a into which the processing liquid is poured from the bucket portion, and a hollow disk 8 constituted by a hollow disk 8. (The detailed structure will be described with reference to FIGS. 2, 6, and 7).
Next, a hollow disk 8 is disposed on both sides of the medium viscosity region, a plurality of hollow thin plates 7b having the same outer diameter are provided therein, and a plurality of scraping plates 6c penetrating these members are radially provided on the outer peripheral portion. A medium-viscosity stirring block (a detailed structure will be described with reference to FIGS. 3, 4, 8, and 9) is provided. Further, on the outlet side, a plurality of wheel-shaped disks 9 are provided at appropriate intervals, and a scraping plate 10 is provided on the outer peripheral portion of the wheel-shaped disks 9 to provide a high-viscosity stirring block (see FIG. (Described with reference to FIG. 10). Further, an outlet nozzle 11 for the liquid to be treated is attached to the lower end of the other end of the main body 1. Further, a volatile matter outlet nozzle 14 is provided at an upper portion of the main body 1 and connected to a condenser and a vacuuming device (not shown) by piping.

In such an apparatus, the inlet nozzle 11
The low-viscosity liquid to be treated (prepolymer) having a lower degree of polymerization supplied more continuously is first stirred in a low-viscosity stirring block shown in FIG. The viscosity of the processing liquid at this time is several Pas to several tens Pas. Low viscosity stirring block is hollow disk 8
A bucket is formed by scraping plates 6a and 6b on the outer peripheral portion of. When it rotates as shown in the figure, it operates to scoop up the processing liquid in the bucket. FIGS. 6 and 7 schematically show the flow states of the processing liquid at this time. Small gap δ at bottom of bucket of scraping plates 6a, 6b (Fig. 2)
Are formed. For this reason, a part 100 of the low-viscosity processing liquid 91 staying at the bottom of the container is picked up by the bucket with the rotation of the stirring rotor, the bucket is tilted inward by the rotation, and the processing liquid flows out to the inside (101 in FIG. 6). The liquid films 101 and 102 are formed on both the inside and the outside of the bucket by gradually leaking to the outside (102 in FIG. 6). Further, the processing liquid 101 which has flowed inward is poured into the thin disk 7a installed at the tip of the inner bucket (103 in FIG. 7), and the surface of the thin disk 7a and the thin disk 7a and the thin disk 7a A thin liquid film 103 is formed on both sides, and a wide evaporation surface area can be secured. These actions are repeated every time the bucket rotates, and a sufficient evaporation surface and a good surface renewal action can be obtained. At this time, sufficiently good performance can be obtained even at a low speed of 0.5 to several rpm (10 rpm or less), and a great effect can be obtained in reducing the power consumed by stirring. The by-product evaporated from the processing liquid is the hollow portion 20a of the hollow disk 8 and the hollow portion 20a of the thin disk 7a.
a and is discharged from the outlet nozzle 14 of the volatile matter. The treatment liquid having passed a predetermined residence time in the low-viscosity stirring block raises the viscosity to about several tens Pas and reaches the next medium-viscosity stirring block. 3 and 4 show the detailed structure of the medium-viscosity stirring blade block. The medium-viscosity stirring blade block is composed of a hollow disk 8, a thin hollow disk 7b and a scraping plate 6c. The hole diameter D1 of the hollow disk and the hole diameter D3 of the thin disk 7b depend on the amount of reaction by-product gas of the processing liquid. The diameter is determined so as to be optimal according to the diameter. The optimum diameter of the hole diameter D2 of the thin disk 7b is also determined according to the viscosity of the processing liquid and the amount of the reaction gas. The processing liquid 92 that has reached several tens Pas is lifted up by the scraping plate 6c by rotation as shown in FIGS. 8 and 9, and furthermore, the scraping plate is inclined by the rotation, so that the liquid hangs down to form a liquid film 104. The liquid film 104 hangs on the connection strength member 5a of the stirring rotor with rotation, and the liquid film is held for a long time. Further, the processing liquid dragged by the rotation is dripped into the hollow portion 20 a of the hollow disk 8 to form a liquid film 105. Similarly, the thin film disk 7b is
07 is formed, and the processing liquid further hangs down to the small holes 20b provided in the thin disk 7b to form the liquid film 106. While forming such a liquid film, the treatment liquid further increases the degree of polymerization due to a large evaporation surface area and a good surface renewal action, and the viscosity of the treatment liquid increases. Treatment liquid viscosity is several hundred Pas
Then, it is processed in the next stirring block for high viscosity. In the stirring block for high viscosity, a scraping plate 10a is attached to an outer peripheral portion of a wheel-shaped disk 9 as shown in FIG. Such wheel-shaped discs 9 are connected in a horizontal direction at predetermined intervals by stirring strength members 5a, 5b, 5c, and 5d. At this time, the scraping plates before and after the wheel type disk 9 are 1
0a and 10b are alternately installed, and the horizontal length of the scraping plate is such that when the disc rotates, the trajectories of the tips overlap each other and scrape the entire inner wall surface of the tank. As shown in FIG. 10, the processing liquid 93 reaching several hundred Pas is lifted by the scraper 10a by the rotation of the stirring blade. The lifted processing liquid is dripped by rotation to form a liquid film 108. At this time, a liquid film 109 is also formed in the hollow portion of the wheel-shaped disc 9 to create a complicated liquid surface shape. When the viscosity of the processing liquid further increases and reaches several thousand Pas, the amount of the liquid lifted increases. If the number of revolutions is increased in such a state, a rotating phenomenon occurs in which the processing liquid is stirred up again before the treatment liquid drips. Therefore, it is necessary to operate at a number of revolutions of 10 rpm or less. The optimum operating range needs to be lowered as the viscosity of the processing liquid increases, and in our experiments, it was 0.5 to 6 rpm.
The range of m was optimal. As described above, the stirring and the surface renewal action are repeated to promote the polycondensation reaction. The volatiles generated by the reaction move sequentially in the longitudinal direction in the main body 1 through the hollow portion of the hollow disk and are discharged from the volatile matter nozzle 14 to the outside of the system. The liquid to be treated having a high degree of polymerization and a high viscosity is discharged from the outlet nozzle 12 to the outside of the system.

When polymerizing polyethylene terephthalate with such an apparatus, an intermediate polymer of the liquid to be treated is continuously supplied from the inlet nozzle 11 and the surface is renewed by stirring with the stirring rotor 4 to carry out the polymerization reaction. The resulting volatile matter such as ethylene glycol is removed by evaporation, and the polycondensation reaction proceeds to form a polymer having a high viscosity. Volatile substances such as ethylene glycol separated during this time are discharged from the outlet nozzle 14. The operating conditions at this time are, for example, a liquid temperature of 260 to 300 ° C. and a pressure of 0.01 to 10 k.
It is performed in the range of Pa and the number of rotations of 1 to 10 rpm. Then, the polymer is discharged from the outlet nozzle 12 to the outside of the system. At this time, the polymer is stirred in the main body 1 in a substantially completely self-cleaning state and undergoes good surface renewal, so that a high quality product polymer can be efficiently obtained without deterioration due to stagnation.

Similarly, the present invention can be applied to continuous bulk polymerization of polycondensation resins such as polyamide and polycarbonate.

[0010]

According to the present invention, good surface renewal can be performed by stirring the processing liquid with the optimum stirring block according to the viscosity of the processing liquid, and a high quality polymer can be efficiently produced. .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing one embodiment of a continuous polycondensation apparatus according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

FIG. 5 is a sectional view taken along line DD of FIG. 1;

FIG. 6 is a schematic diagram showing a flow of a processing liquid in a bucket portion of a low-viscosity stirring block.

FIG. 7 is a schematic diagram showing a flow of a processing liquid near a thin disk of a low-viscosity stirring block.

FIG. 8 is a schematic diagram showing a flow of a processing liquid near a hollow disk of a medium viscosity stirring block.

FIG. 9 is a schematic diagram showing a flow of a processing liquid in a thin disk shape of a medium viscosity stirring block.

FIG. 10 is a schematic diagram showing a flow of a processing liquid in a high-viscosity stirring block.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Container main body, 3a, 3b ... Shaft for rotation support, 4 ... Stirring rotor, 5a, 5b, 5c, 5d ... Strength member for stir rotor construction, 2 ... Rotor support member, 6a, 6b, 6c ... Scraping plate , 7a, 7b ... thin disk, 8 ... hollow disk, 9 ...
Wheel-shaped disks, 10a, 10b: scraping plate, 11: inlet nozzle, 12: outlet nozzle, 14: volatile nozzle, 20a, 20b, 20c: hollow portion, 91, 92, 9
3 ... treatment liquid level, 100, 101, 102, 103, 1
04, 105, 106, 107, 109, 110: liquid film.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroo Suzuki 794, Higashi-Toyoi, Kazamatsu-shi, Yamaguchi Prefecture Inside the Kasado Plant of Hitachi, Ltd.

Claims (8)

[Claims] 1. A substantially horizontal cylindrical container body has an inlet and an outlet for a liquid to be treated at one lower end and the lower end of the other end in the longitudinal direction of the main body, and has an outlet for volatile matter at an upper part of the main body. In a device provided with a stirring rotor that rotates close to the inside of the main body in the longitudinal direction, the stirring rotor inside the main body is composed of a plurality of stirring blade blocks according to the viscosity of the processing liquid, and is rotated around the center of the stirring rotor. A continuous polycondensation apparatus characterized by having no shaft. 2. The continuous polycondensation apparatus according to claim 1, wherein
The stirring block for low viscosity is provided with hollow disks at both ends, and the outer peripheral portion of the disks is constituted by two scraping plates that scrape the processing liquid adhered to the inner surface of the container body and stayed at the bottom of the container. A bucket portion for scooping up the processing liquid by the rotation of the blade is provided, and a plurality of hollow thin disks are installed in the vicinity of the inner peripheral end surface of the scraping plate, and the processing liquid collected in the bucket portion by the rotation of the blade is hollow. Continuous polycondensation characterized by a structure in which a liquid film is formed between thin disks by being poured into a thin disk, and a plurality of the stirring blocks are connected to form a stirring block for low viscosity. apparatus. 3. The continuous polycondensation apparatus according to claim 2, wherein
A continuous polycondensation apparatus characterized in that a bucket portion for scooping up a processing liquid formed by a scraping plate is provided with a hole or a slight gap through which a processing liquid flows out at a horizontal joint of the scraping plate on the bottom side. 4. The continuous polycondensation apparatus according to claim 1, wherein
The stirring block for medium viscosity is provided with a hollow disk at both ends, and a plurality of other scraping plates are radially provided on the outer periphery of the disk,
Further, continuous polycondensation is characterized in that a plurality of hollow thin plates having the same size as the outer circumference of the disk are provided between the hollow disks, and a plurality of stirring blocks having a plurality of small circular holes are connected to the thin plates. apparatus. 5. The continuous polycondensation apparatus according to claim 1, wherein
The stirring block for high viscosity has a continuous weight characterized by arranging a plurality of wheel-shaped disks with scraping plates in the horizontal direction and alternately setting the mounting positions of the front and rear scraping plates to form a stirring block. Condensing equipment. 6. A continuous polycondensation apparatus according to claim 1, wherein a prepolymer having a low polymerization degree is continuously supplied from an inlet nozzle,
By rotating the rotor and agitating the processing liquid while forming the optimal liquid film with each agitation rotor, good surface renewal is performed to evaporate volatile substances such as ethylene glycol and move toward the outlet to polymerize. Polyethylene terephthalate continuous polycondensation method to increase the degree. 7. The apparatus according to claim 1, wherein the viscosity of the processing solution at the inlet is several Pas or more, and the viscosity of the processing solution at the outlet is several kP.
A continuous polycondensation apparatus and an operation method, wherein the apparatus is operated in the range of as or less. 8. The continuous polycondensation apparatus according to claim 1, wherein the rotation range of the stirring blade is 0.5 rpm to 10 rpm.