JPH10218998A - Production of polycondensation polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a polycondensation polymer having a high degree of polymn. at a low equipment cost. SOLUTION: The vessel 1a of a polycondensation reactor 1 is equipped with an inlet port 2 for raw materials near at the one end and an outlet port 3 for polymn. products and an outlet port 4 for volatile substances near at the other end. Blades 10 are installed between arrow-wheel-like arm rotators 5, 6 installed at both ends of the vessel 1a. Blade pieces 10a have widths (lengths in the peripheral direction of the vessel 1a) decreasing gradually from the side of the inlet port 2 toward the side of the outlet port 3. A plurality of doughnut- like circular boards 13 having the same outer edges as those of the blades 10 are installed between the blades 10, and the installation distances and inner diameters of the circular boards 13 are gradually increased from the side of the inlet port 2 toward the side of the outlet port 3. The blade piece has slits 9 formed therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polycondensation-based polymer which increases the viscosity in the polymerization step, for example, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polycarbonate, and other polyesters, and the method for increasing the viscosity. The present invention relates to a method for detaching volatile components and the like from a molten fluid.

[0002]

2. Description of the Related Art Conventionally, when a polycondensation polymer such as polyethylene terephthalate (hereinafter abbreviated as PET) is to be polymerized to a high degree of polymerization, a polycondensation reactor is disclosed in Japanese Patent Application No. 52-14769. It is a combination of such devices. One is a single-shaft disc-type polymerization reactor (having a central axis in a vessel) as a first-stage reactor, a two-shaft disc-type polymerization reactor as a second-stage reactor, and a two-shaft 8 as a third-stage reactor. This is achieved by connecting a three-stage polymerization reactor (trade name: glasses-type stirring blade) and a reactor. The other is to improve the permissible operating viscosity of the first-stage reactor, propose a mechanism to provide a scraper or the like on the inner wall of the vessel, and prevent stagnation of the polymer adhering to the surface of the stirring blade and the central shaft. . As a result, the degree of polymerization at the outlet of the first stage reactor is increased, and
We manufacture PET with a high degree of polymerization in combination with an 8-shaft polymerizer.

[0003]

In the former case shown in the prior art, the single-shaft disk-type polymerization reactor of the first-stage reactor has a disk-shape in which a central shaft is provided and an opening is provided in the central shaft. Of a polymer having a viscosity of about 1
When the water pressure reaches 000 poise, the polymer adhering to the stirring blade rotates around the stirring blade to form a stagnant portion of the polymer on the surface of the blade or on the surface of the central axis, so that the maximum operating viscosity becomes about 1,000 poise or less. For example, if the degree of polymerization is to be further increased as in polyester for tire cords (viscosity is about 20,
2,000 poises), and two or more twin-screw reactors are required in the subsequent stage.

In the latter, by providing a scraper, the polymer on the surface of the stirring blade and the central shaft is scraped, and the stagnation of the polymer at that portion is alleviated, and the co-rotation phenomenon is prevented. A stagnation portion will be formed on the back surface of the scraper, and the effect is small. Further, even if such a scraper is provided for the surface of the stirring blade or the surface of the central shaft, the maximum allowable operating viscosity can be increased only up to about 4000 poise, and the capacity of the post-stage polymerization vessel becomes large ( Compared with the single-shaft type, the two-shaft type has a very high cost even with the same capacity), but also has the disadvantage of being disadvantageous in cost.

[0005]

SUMMARY OF THE INVENTION The present invention provides a method for producing a polycondensation polymer having a high degree of polymerization at a low cost by connecting two stages of polycondensation reactors. The present invention relates to a method for producing a high-viscosity polymer by continuous melt polycondensation by a polycondensation reaction step, wherein the polycondensation step comprises a pre-stage polycondensation reactor and a post-stage polycondensation reactor. The reactor is a substantially horizontally placed cylindrical container having an L / D of 2 to 10, preferably 4 to 6, wherein the internal diameter of the cylindrical container is D, and the axial length of the container is L,
The positions of the axial centers of both ends of the cylindrical container are set as pivot points, and the inner peripheral wall of the cylindrical container and the inner peripheral wall of the cylindrical container are 0.005 substantially parallel to the axis of the cylindrical container.
D to 0.03D, with a gap provided so as to be rotatable in the longitudinal direction of the cylindrical container, attached at an angle so that the axial center side precedes the rotational direction, and attached to the rotational direction. The rear side is slightly bent in the axial direction, and the position of the axial side is set at 0. 0 relative to the inner diameter of the container.
A plurality of wing plate pieces positioned outside of 75D, and a plurality of donut-shaped disks fixed to the wing plate pieces so as to be substantially orthogonal to the wing plate pieces, substantially in a lattice set. Inside the cylindrical container, a rotating body for liquid stirring and mixing having no central axis is provided, and the width of the wing plate piece is configured to decrease stepwise from the inlet to the outlet of the processed material, The donut-shaped disk has a structure in which the mounting interval and the inner diameter of the donut-shaped disk are gradually increased from the inlet to the outlet of the processed product, and the melt polymer viscosity at the outlet of the pre-stage polycondensation reactor is 5,000 to 15,
A method for producing a polycondensation polymer is adopted, in which the reaction is allowed to proceed to 000 poise, and the discharged liquid is continuously supplied to the latter-stage polycondensation reactor to further promote the reaction.

[0006] Thus, the disadvantages of the prior art can be solved, and a very high-viscosity polymer can be produced with high quality at low equipment cost. The feature of the method for producing a polycondensation polymer according to the present invention is that the agitating blade shape of the pre-stage polycondensation reactor eliminates the central axis in the vessel, and a plurality of blades are provided in the vessel in the longitudinal direction. And a plurality of donut-shaped disks are fixed on the
With a very simple structure located outside of D,
The point is that the stagnation portion of the polymer having increased viscosity is eliminated, and the allowable operation viscosity is remarkably increased as compared with the conventional uniaxial polymerization vessel. In addition, this makes it possible to greatly reduce the capacity of the later twin-screw reactor, which is more expensive than the single-screw reactor, and to greatly reduce equipment costs.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the method for producing a polycondensation polymer according to the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a flow in one embodiment of the production method of the present invention, where 30 and 31 are esterification reactors, 1 is a pre-stage polycondensation reactor, and the details thereof are shown in FIGS.
Reference numeral 21 denotes a second-stage polycondensation reactor.
No. 064113 and the like. 3
Reference numerals 2, 33, and 34 denote transportation means such as a pump for sequentially transporting the polymer to the next reactor.

FIG. 2 shows the structure and operation of the first-stage polycondensation reactor 1.
This will be described in detail with reference to FIGS. In FIG. 2, 1a
Is a cylindrical container placed substantially horizontally, and this container 1a
Has an inlet 2 for the raw material near one end, an outlet 3 for the polymer near the other end, and an outlet 4 for volatiles. The rotator-shaped arm rotating bodies 5 and 6 provided at both ends in the container 1a are respectively fixed to rotating shafts 7 and 8 inserted from outside the container 1a into holes provided in the axis of the container 1a. I have. Each of the rotating shafts 7, 8 is supported by a bearing 12, and is rotated at an appropriate rotation speed by a driving device (not shown).

A wing plate 10 is disposed between the wheel rotating bodies 5 and 6 in the shape of a wheel. The wing plate 10 is provided with a slit 9 and, as shown in FIGS. 3 to 10, a plurality of flat wing plate pieces 10 a with one end slightly bent and arranged in the circumferential direction of the container 1 a. It is. The blade piece 10a is disposed so as to be inclined such that the front end preceding the rotation direction is lowered by about 45 ° toward the axis. A plurality of blades 10 are fixed at a position where the rear end side in the rotation direction keeps a slight gap with the container 1a, as shown in FIGS.
The plate width (the length in the circumferential direction of the container 1a) is gradually reduced from the inlet 2 side to the reactant outlet 3 side. That is, in the example of FIG. 2, the width of the blade 10 is reduced by dividing the region into the entrance 2 side region 14a, the central region 14b, and the exit side region 14c in three stages. Although the slits 9 provided in the wing plate 10 have two rows in this example, the slits 9
The number and size of are adjusted appropriately according to the viscosity of the reaction solution.

A donut-shaped circle whose outer diameter matches the outer end of the blade 10 is provided between the blades 10 in order to suppress mixing of the polymer remaining in the container 1a in the longitudinal direction of the container 1a. A plurality of plates 13 are mounted at intervals from each other;
The mounting interval and the inner diameter of the donut-shaped disc 13 are gradually increased from the inlet 2 side of the container 1a to the reactant outlet 3 side. In this manner, the wing plate 10 fixed between the arm rotating bodies 5 and 6 and the donut-shaped disk 1
In the lattice set composed of 3, the inlet 2 side is densely arranged near the center of the container 1a, and the outlet 3 side is coarsely arranged.

The specific size of the first-stage polycondensation reactor 1 is as follows:
L / D, where D represents the inner diameter of the cylindrical container and L represents the axial length of the container, is 2 to 10, preferably 4 to 6. The range in which the wing plate pieces 10a are disposed is set such that the axial center positions of both ends of the cylindrical container are used as pivot points, and the inner peripheral wall of the cylindrical container 1a and the rear end of the wing plate pieces 10a are 0 0.005D to 0.03D
And the position on the axis side is set to the inner diameter D of the container 1a.
Is located outside of 0.75D.

Next, the operation and operation of the method for producing a polycondensation polymer according to the present embodiment will be described. In the polymerization reactor having the above-described structure, the intermediate polymer supplied from the inlet 2 of the raw material is supplied to the slit 9 inside the container 1a.
Along the inner wall surface of the container 1a can be lifted by the attached wing plate 10. The raw material lifted by the blade piece 10a is supplied to the slit 9 where the blade piece 10a is located in the gas phase.
And into the gaseous phase because there is no member that hinders the high-viscosity polymer from flowing down from the bent portion provided on the surface of the wing plate piece 10a and on the rear side of the wing plate piece 10a. The effect of exposing efficiently, that is, the surface renewal effect is large, and the effect of stirring the polymer is excellent.

At this time, the region 14 on the inlet 2 side of the raw material is
a, the viscosity of the intermediate polymer supplied from the inlet 2 is low, and here, the vanes 10 with slits 9 are closely arranged.
And the lattice set of the donut-shaped disks 13 perform a surface renewal action of the intermediate polymer to a position close to the center, thereby promoting the separation and polymerization of volatile gas densely, and the central region 14b of the container 1a. In this case, the surface renewal effect is slightly moderate on the circumferential side. On the other hand, the region 14c on the polymer exit 3 side
In places where the viscosity of the polymer becomes extremely high at 5,000 poises or more, a gradual surface renewing action only along the inner wall surface of the container 1a is performed by a lattice group roughly arranged near the circumference, and the container 1a The co-rotation phenomenon of the polymer in the central portion of the polymer is eliminated, the flow of the polymer substance to the outlet 3 becomes smooth, and a good residence time distribution (piston flow property) can be obtained.

For this reason, in the polymerization of the polycondensation polymer, even if the viscosity of the polymer reaches a very high value of 5,000 poise or more, the volatile gas can be efficiently removed. As described above, the viscosity was 50
The polymer that has been polymerized to 00 to 15000 poises is sent to the second-stage polycondensation reactor 21 by the liquid sending pump 34 in order to further increase the weight, and after being polymerized to a predetermined polymerization degree, the final polymer Is taken out as As the second-stage polycondensation reactor 21, a twin-screw reactor such as Japanese Patent Application No. 62-064113 is used as an agitation device for an ultra-high viscosity liquid.

[0015]

EXAMPLES Hereinafter, examples of the method for producing a polycondensation polymer according to the present invention will be specifically described using polymerization examples of polyethylene terephthalate.

(Embodiment 1) 1.0 mol of terephthalic acid, ethylene glycol 1.
27 kg / hour of raw material slurry mixed at a ratio of 5 mol
, And was continuously supplied to the first-stage esterification reaction tank 30. In this slurry, antimony trioxide as a catalyst and triphenyl phosphate as a stabilizer were added at a ratio of 350 ppm and 300 ppm, respectively, to the raw material slurry. The esterification reaction was carried out in the first and second stage esterification reaction tanks 30 and 31 to a conversion of about 95%. At this time, the conditions of the first-stage and second-stage esterification reaction tanks 30 and 31 are such that the temperature is both 260 ° C. and the residence time is 4.
5 hours and 2 hours.

Next, the prepolymer was heated at a temperature of 270 ° C.
The pressure was controlled at 1 Torr. The single-shaft pre-stage polycondensation reactor shown in FIG. 2 (vessel inner diameter 300 mm, L / D = 4,
It is pushed into a stirring blade rotation diameter of 296 mm, an internal volume of 85 liters, and a stirring rotation number of 5 rpm by a gear pump 33 connected to an outlet of the second-stage esterification reaction tank 31.
The polymerization was carried out in 5 hours. The intrinsic viscosity (η) of the obtained polymer was 0.76 dl / g. The melt viscosity of the obtained polymer was about 5800 poise.

Next, this polymer was subjected to a temperature control of 285 ° C. and a pressure of 0.3 Torr, as disclosed in Japanese Patent Application No. 62-064.
No. 113, a two-shaft horizontal stirring type post-polymerizer having a self-cleaning function (L / D = 6, stirring blade rotation diameter 2)
(40 mm, internal volume 60 liters, stirring speed 8 rpm)
Then, the mixture was pushed by the gear pump 34 at the outlet of the pre-stage polymerization vessel, and was polymerized for a residence time of 40 minutes. The intrinsic viscosity (η) of the obtained polymer was 1.12 dl / g. Table 1 shows the test results.

(Example 2) In the first-stage polycondensation reactor 1 in Example 1, the same polymerization as in Example 1 was carried out except that the temperature was changed to 285 ° C, and the obtained polymer was analyzed in the same manner. . Table 1 shows the test results.

Example 3 A polymer obtained by performing the same polymerization as in Example 1 except that the rotation speed of the post-stage polycondensation reactor 21 was changed to 15 rpm, was analyzed in the same manner. Table 1 shows the test results.

(Example 4) In Example 1, the polymer to be sent to the first-stage polycondensation reactor 1 from the gear pump 33 connected to the outlet of the second-stage esterification tank 31 was partially and continuously extracted out of the system. Same as Example 1 except that the amount of polymer to be sent to the polycondensation reactor 1 was reduced, the residence time of the pre-stage polycondensation reactor 1 was set to 2 hours, and the retention time of the post-stage polycondensation reactor 21 was set to about 53 minutes. The same analysis was performed on the polymer obtained by performing the various polymerizations. Table 1 shows the test results.

[0022]

[Table 1]

The methods for measuring the intrinsic viscosity and the melt viscosity in Table 1 are as follows. (1) Intrinsic viscosity phenol and 1, 1, 2, 2
The measurement was performed using an Ubbelohte viscometer using a mixed solvent at 20 ° C. in which the weight ratio of tetrachloroethane was 4 to 6. (2) Melt viscosity Each polycondensation was conducted using a double-cylindrical rotary viscometer (HAAKE, Germany) having a rotating cylinder with an outer diameter of 20.2 mm and a length of 61.4 mm within a fixed container inner diameter of 23.1 mm. The measurement was performed under the operating temperature conditions of the reactors 1 and 21.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical concept of the present invention. For example, in the above embodiment, polyethylene terephthalate (PE
Although T) has been described as an example, the present invention is, of course, also effective for polycondensation polymers other than PET.

[0025]

According to the present invention, an inexpensive single-shaft pre-stage polycondensation reactor is used to adjust the polymer viscosity to a high viscosity range (viscosity of 5,000 to 1500, which cannot be operated with a conventional single-shaft reactor).
Since the operation can be performed up to 0 poise), the capacity of, for example, a biaxial polycondensation reactor provided in the subsequent stage can be significantly reduced. In the latter-stage polycondensation reactor, it is necessary to treat a polymer that further increases the viscosity, so it becomes an expensive facility.
By polymerizing to as high a viscosity range as possible, the total cost can be significantly reduced by making the subsequent reactor compact. If the requirement for the final degree of polymerization is low (for example, the final polymer viscosity is 15,000 poise or less), it can be processed up to the pre-stage polycondensation reactor according to the present invention, and it is necessary to provide a post-stage polycondensation reactor. And cost can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a process chart showing a flow of production of a polycondensation polymer according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a pre-stage polycondensation reactor.

FIG. 3 is a cross-sectional view taken along a line SS in FIG. 2;

FIG. 4 is a cross-sectional view taken along a line TT in FIG. 2;

FIG. 5 is an enlarged sectional view of a portion U in FIG. 4;

FIG. 6 is a sectional view taken along the line VV in FIG. 2;

FIG. 7 is an enlarged sectional view of a portion W in FIG. 6;

FIG. 8 is a cross-sectional view taken along a line XX in FIG. 2;

FIG. 9 is an enlarged sectional view of a portion Y in FIG. 8;

FIG. 10 is a sectional view taken along the line ZZ in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pre-stage polycondensation reactor 1a Vessel 2 Inlet 3,4 Exit 5,6 Arm rotating body 7,8 Rotation axis 10 Blade plate 10a Blade plate piece 13 Disk 21 Post-stage polycondensation reactor

Claims (1)

[Claims] 1. A method for producing a high-viscosity polymer by continuous melt polycondensation in a polycondensation reaction step, wherein the polycondensation reaction step is performed by a first-stage polycondensation reactor and a second-stage polycondensation reactor. The first-stage polycondensation reactor has an L / D of 2 to 10, preferably 4 to 6, where D represents the inner diameter of the cylindrical vessel and L represents the axial length of the vessel, and is placed substantially horizontally. In a cylindrical container provided with an inlet for supplying a processed material at one end and an outlet at the other end, the axial center positions of both ends of the cylindrical container are used as pivot points, and the inner peripheral wall of the cylindrical container and 0.005D to 0.03D. And a rotatable rotatable rotatable mixing and stirring liquid having substantially no center axis and having a gap of 0.75 with respect to the inner diameter of the cylindrical container.
D, and is disposed with the front end side inclined inward of the cylindrical container with respect to the rotation direction, and the rear end side slightly inward with respect to the rotation direction. A blade is provided in which a plurality of bent blades are arranged in the circumferential direction, and a donut-shaped disk is fixedly provided between the blades, and the circumferential length of the blade is set to the above-mentioned length of the processed material. The donut-shaped disk is configured to be gradually reduced from the inlet to the outlet, and the mounting interval and the inner diameter of the donut-shaped disc are gradually increased from the inlet to the outlet of the processed material. The melt polymer viscosity at the outlet of the polycondensation reactor is 500
A method for producing a polycondensation-based polymer, which comprises allowing the reaction to proceed to 0 to 15,000 poises, continuously supplying the discharged liquid to the second-stage polycondensation reactor, and further promoting the reaction.