JP3799249B2 - Stirring apparatus and polymer production method using the apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel stirring device. More specifically, the present invention relates to a stirring device having a self-cleaning function. The present invention also relates to a method for producing high-viscosity polycondensates such as saturated and unsaturated polyesters, polyethers, polyamides, and polycarbonates using this apparatus.
[0002]
[Prior art]
In general, as a synthetic polymer production apparatus, an agitation apparatus having a high mixing performance and heat transfer performance and a function of actively preventing polymer retention, that is, a self-cleaning function is often desired.
[0003]
In particular, in order to produce a polymer that is often used in optical applications, a self-cleaning mechanism in a stirring device is extremely important in terms of quality. For this reason, conventionally, a stirrer having a self-cleaning mechanism has been proposed as a means for treating a sticky substance having strong adhesion.
[0004]
As a stirring device having such a self-cleaning mechanism, two or more stirring shafts are provided in a container, a stirring rotor is attached to them, and a gap between the stirring rotors and between the stirring rotor and the inner wall of the container is kept slightly, and mechanical In addition, there is an apparatus that attempts to prevent the formation of deposits on the inner wall of the container as much as possible (Japanese Patent Laid-Open No. 63-232828).
[0005]
Such a device is a stirring device comprising a plurality of stirring shafts arranged in a container and driven to rotate synchronously, and a plurality of stirring rotors fixed to each stirring shaft and performing a stirring action. The agitation rotor is attached at an interval in the axial direction, and a scraper having a length substantially corresponding to the interval is attached in parallel to the agitation shaft at the tip of the agitation rotor.
[0006]
In this apparatus, the self-cleaning action is performed simultaneously with the stirring action. That is, the pointed ridges of each stirring rotor move close to the inner wall of the vessel, and the curved peripheral surfaces of the stirring rotor of one stirring shaft and the stirring rotor of the other stirring shaft are close to each other. The self-cleaning is performed by moving, the agitating rotor planar side surface and the agitating rotor planar side surface facing them moving close to each other, and the like.
[0007]
[Problems to be solved by the invention]
However, the conventional apparatus having such a self-cleaning function usually has a drawback that a liquid supply port is provided at the bottom of the container and the flow of the liquid to be processed becomes unstable near the supply port. For this reason, it is difficult to uniformly wet the stirring rotor in the vicinity of the liquid supply port with the supply liquid, and there is a problem in that a gas-liquid interface is generated on the surface of the stirring rotor and a deteriorated product is generated in the vicinity of the interface.
[0008]
This tendency is particularly noticeable when a high-viscosity fluid of a polymer is stirred and mixed. A boundary between a gas phase and a liquid phase is generated near the supply port, and the polymer is likely to deteriorate near the interface, so that self-cleaning properties can be obtained. However, in the case of insufficient, it has been necessary to shorten the cleaning interval of the apparatus in order to maintain the product quality, which has been a major factor in increasing the operation cost.
[0009]
The object of the present invention is to solve such problems in the conventional stirring device, improve self-cleaning properties, linear saturated and unsaturated polyesters, polyethers, polyamides, polycarbonates, etc. It is an object of the present invention to provide an apparatus capable of producing a polycondensate of the present invention, and a method for continuously producing a high-quality polymer using the apparatus at a low operating cost.
[0010]
[Means for Solving the Problems]
The present invention is provided with two stirring shafts arranged in parallel in a cylindrical container installed substantially horizontally and synchronously driven to rotate in the same direction. In a stirring device having a plurality of stirring rotors that are fixed by being shifted by 90 degrees around the shaft and are attached to the stirring shaft at intervals in the axial direction, the liquid supply port to the container is connected to the container from the outside. When the rotation of the stirring shaft is counterclockwise, the starting point is vertically upward from the center of the left stirring shaft, the rotation direction of the stirring shaft is positive, and −45 degrees to +90 degrees (however, −45 degrees is If the stirring shaft rotates in a clockwise direction, the center of the right stirring shaft starts at the top and the rotation direction of the stirring shaft is positive. , For a range from -45 degrees to +90 degrees (excluding -45 degrees) A stirring device, characterized in that installed in the container of the end plate or cylinder on which.
[0011]
In addition, the present invention is a method for producing a polymer, characterized in that a polycondensate previously polycondensed is further polymerized by the apparatus of the present invention. In the present invention, the polycarbonate obtained by melt polymerization of an aromatic dihydroxy compound and a carbonic acid diester is supplied to the stirring device of the present invention, and further polymerized by melting and stirring in the device under reduced pressure. A process for producing a polycarbonate characterized by the following:
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific examples of the stirring device of the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 is a horizontal sectional view showing an example of the stirring device of the present invention, and FIG. 2 is a vertical sectional view taken along the line AA ′ of FIG. FIG. 3 is a schematic cross-sectional view of the apparatus of FIGS. 1 and 2 as viewed from the stirring axis direction.
[0014]
(container)
In the agitation apparatus of the present invention, the container 1 is installed substantially horizontally, and the inner wall of the container 1 is a bowl-like shape in which two cylindrical walls each centering on the agitation shaft 2 and the agitation shaft 3 are connected. It has a cross section. The cross-sectional shape of the container 1 is preferably a saddle shape, but is not limited to this.
[0015]
(Stirring shaft)
Two stirring shafts 2 and 3 extending substantially horizontally in the longitudinal direction of the container are provided in the container 1, and these two stirring shafts 2 and 3 are supported by bearings in parallel with each other. The agitation shafts 2 and 3 are rotationally driven in synchronism with each other at the same rotational speed in the same rotational direction as indicated by arrows in the figure by a drive source (not shown).
[0016]
(Stirring rotor)
A plurality of agitation rotors are fixed to the agitation shafts 2 and 3 at predetermined intervals along a plane orthogonal to the agitation axis. As shown in FIGS. 3 to 7, each stirring rotor is formed in a thick plate shape having a spindle-shaped cross section in which the central portion is swollen and both ends are sharp, but the shape can be selected as appropriate. In addition, the number of stirring rotors fixed to each stirring shaft can be selected as appropriate, but it is appropriate to arrange the stirring rotors almost uniformly over the entire stirring shaft. As shown in FIG. 4, when the diameter of the rotor is D, the radius of curvature of the rotor is preferably D / √2.
[0017]
As shown in FIG. 1, FIG. 2, FIG. 11, and FIG. 12, the stirring rotor fixed to each stirring shaft is separated from the cylindrical inner wall of the container 1 or adjacent to it by a slight gap according to its rotational angle position. The dimensions are selected so as to face the stirring rotor fixed to the corresponding adjacent stirring shaft.
[0018]
That is, a plurality of (19 in FIG. 1 and FIG. 2) agitation rotors 4a, 4b, 4c,... 4s are fixed to one agitation shaft 2 at a predetermined interval. These stirring rotors are attached to the stirring shaft 2 along a plane perpendicular thereto. These agitating rotors face the corresponding agitating rotors 5a, 5b, 5c,... 5s fixed to the one cylindrical wall or the other agitating shaft 3 with a slight gap depending on the rotational angle position. The dimensions are selected to obtain.
[0019]
On the other hand, a plurality of stirring rotors 5 a, 5 b, 5 c,... 5 s are similarly fixed to the stirring shaft 3 (19 in FIG. 1 and FIG. 2, the same number as the stirring rotor of the stirring shaft 2). Each agitating rotor is located at the same axial position corresponding to the corresponding agitating rotor of the agitating shaft 2, and each agitating rotor is attached to the agitating shaft 3 with a phase shifted by 90 degrees with respect to the corresponding agitating rotor. It has been.
[0020]
Each of the stirring rotors can be opposed to the cylindrical inner wall of the container 1 or each of the corresponding stirring rotors with a slight gap depending on the rotation angle position. Further, the side surfaces are opposed to the adjacent stirring rotors adjacent to each other with a slight gap in the axial direction. The agitation rotor fixed to the agitation shaft 2 and the agitation rotor fixed to the agitation shaft 3 are positioned in the same axial direction as the corresponding agitation rotor, and each has a phase of 90 with respect to the corresponding agitation rotor. It is attached to the stirring shaft in a deviated form. Further, the side surfaces of the respective stirring rotors are opposed to the corresponding stirring rotors adjacent to each other with a slight gap therebetween in the axial direction.
[0021]
(Scraper)
Although the scraper is not provided in each stirring rotor in the apparatus shown in FIGS. 1-3, a scraper may be provided in the tip of each stirring rotor like the apparatus shown in FIGS. 11-13, and that is often preferable. When a scraper is provided at the tip portion of the stirring rotor, the self-cleaning property can be further improved.
[0022]
The scraper is preferably attached to the tip of the stirring rotor in parallel with the stirring shaft. As for the shape, it is preferable that the outer surface coincides with the outer peripheral surface of the stirring rotor and has a pseudo-triangular cross section as indicated by 12 in FIG. Further, it is preferable that the length 13 of the scraper is approximately the same as the distance between the stirring rotors as shown in FIG.
[0023]
(Liquid outlet)
Usually, the liquid outlet 9 is often attached to the lower part of the cylinder 10 of the container 1.
[0024]
(Liquid supply port)
The present invention is characterized in that the liquid supply port 8 is opened on the end plate 6 or the cylinder 10 of the container 1 and the position thereof is selected as follows.
[0025]
In the present invention, the liquid supply port 8 to the container 1 is provided at a position indicated by hatching in FIGS. 4-7 is a schematic diagram explaining the position of the liquid supply port when the stirring apparatus of this invention is seen from the outer side.
[0026]
In the stirring device of the present invention, the solution to be treated is introduced into the container 1 from the liquid supply port provided in the range shown by oblique lines in FIG. 4 to FIG. 3 is driven to rotate and is sufficiently stirred by the movement of each stirring rotor, and then is taken out from the liquid outlet 9.
[0027]
The stirring device of the present invention is characterized in that the liquid supply port is installed at a specific position where the solution supply port is not provided in the conventional device.
[0028]
That is, when the container is viewed from the outside, when the stirring shaft rotates counterclockwise as shown in FIGS. 4 and 5, the liquid supply port 8 is set vertically upward from the center of the left stirring shaft 2. Is set on the end plate 6 (shown in FIG. 4) or the cylinder 10 (shown in FIG. 5) of the container corresponding to the range of −45 ° to + 90 ° with the rotation direction of the stirring shaft as positive.
[0029]
Also, as shown in FIGS. 6 and 7, when the rotation of the stirring shaft is clockwise, the liquid supply port 8 starts from the vertical upper side from the center of the right stirring shaft, and the rotation direction of the stirring shaft is positive. It is characterized by being installed within the range projected on the end plate 6 (shown in FIG. 6) or the cylinder 10 (shown in FIG. 7) of the container corresponding to the range of −45 ° to + 90 °. is there. 8 and 9 are vertical sectional views of the apparatus showing the liquid supply port 8.
[0030]
The present invention is based on the finding that in the horizontal stirring device, the second quadrant shown in FIG. 10 has the lowest solution retention amount inside the stirring device.
[0031]
That is, as shown in FIG. 10, the horizontal stirring device generally has a positive rotation direction starting from a point on the cylinder vertically above the stirring shaft mainly due to the influence of gravity and the rotational movement of the stirring rotor. In the quadrant II shown in FIG. 10, which is above the horizontal plane passing through the center of the stirring axis of the cylinder of the apparatus, the amount of solution staying in the stirring apparatus is most reduced. This is based on the finding that it is possible to eliminate the non-uniform amount.
[0032]
In the conventional apparatus, when the rotation direction of the stirring shaft is counterclockwise, the range of y ≧ 0 (the first quadrant and the second quadrant) and y <0 are obtained when taking the xy coordinate system as shown in FIG. In the range of (quadrant III and quadrant IV), the amount of polymer retention is smaller when y ≧ 0 due to the influence of gravity. Further, when comparing the range of x ≧ 0 (quad I and IV quadrants) and the x <0 range (quad II and III quadrants), since the rotation direction is counterclockwise, x <0 The range (second quadrant, third quadrant) is low in polymer retention.
[0033]
Therefore, in the coordinate system shown in FIG. 10, the self-cleaning property could not be maintained because the polymer retention amount in the range of y ≧ 0 and x <0 (quad II quadrant) was the smallest.
[0034]
However, according to the present invention, as already described in detail with reference to FIGS. 4 to 7, when the end plate is viewed from the outside of the container and the shaft rotates counterclockwise, it is vertically above the stirring shaft on the left side of the end panel 6 of the container. If the rotation direction of the shaft is clockwise within a range of −45 ° to 90 °, the rotation is started from the vertical top 11 of the stirring shaft on the right side of the end plate 6 of the container. If the direction is positive, by installing the liquid supply port 8 within the range of −45 ° to 90 °, the stirring rotor near the liquid supply port, which has been difficult to wet, can be sufficiently wetted so far. .
[0035]
And since the non-uniformity of the stay of the solution in the vicinity of the liquid supply port in the apparatus is eliminated, the liquid is filled in the apparatus without unevenness. The self-cleaning property is improved, and it becomes possible to produce a high-quality polymer that is free from polymer deterioration and gel generation even if it is operated for a long time.
[0036]
In this case, the position of the liquid supply port 8 is better as it is closer to the end plate 6. Preferably, the self-cleaning property is better when the solution to be processed is directly supplied to the stirring rotor in the vicinity of the end plate 6. .
[0037]
(Method for producing polycondensation polymer)
The present invention also provides a method for continuously producing a polymer while maintaining product quality at a low operating cost.
[0038]
That is, the present invention provides a method for producing a polymer, characterized in that a polycondensate that has been polycondensed in advance is further polymerized by the apparatus of the present invention. Examples of the polycondensate include saturated and unsaturated polyesters, polyethers, polyamides, and polycarbonates.
[0039]
The present invention can be applied to the melt polymerization of aromatic polycarbonates among the above-mentioned saturated and unsaturated polymers. That is, the present invention relates to a polycarbonate obtained by melt polymerization of an aromatic dihydroxy compound and a carbonic acid diester, preferably a polycarbonate having an intrinsic viscosity [η] of about 0.2 to 0.35 by using the above stirring device. A process for producing a polycarbonate having a higher degree of polymerization by further melt polymerization under the following conditions.
[0040]
Examples of the aromatic dihydroxy compound used here include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, and 2,2-bis (4-hydroxyphenyl) octane. Bis (hydroxyaryl) such as bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxy-t-butylphenyl) propane ) Alkanes, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (hydroxyphenyl) cyclohexane, 4,4′-dihydroxydiphenyl ether, etc. Dihydroxy aryl ethers, 4,4'-dihydroxydiphenyl Dihydroxyaryl sulfides such as Rufido, 4,4'-dihydroxy aryl sulfoxides such dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy aryl sulfones, such as dihydroxy diphenyl sulfone and the like are used. In particular, 2,2-bis (4-hydroxyphenyl) propane is preferred.
[0041]
Examples of the carbonic acid diester include esters such as an aryl group having 6 to 10 carbon atoms and an aralkyl group which may be substituted. Specific examples include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, and the like.
[0042]
The melt polymerization reaction of an aromatic dihydroxy compound and a carbonic acid diester is performed by distilling off an aromatic monohydroxy compound produced by stirring while heating in an inert gas atmosphere as is conventionally known. The reaction temperature is usually in the range of 120 to 350 ° C., and in the latter stage of the reaction, the aromatic monohydroxy compound produced by increasing the degree of vacuum of the system to 1 to 0.1 Torr is easily distilled, and the intrinsic viscosity [η] Gives a polycarbonate of about 0.2 to 0.35.
[0043]
Here, the intrinsic viscosity [η] is measured with a Ubbelohde viscometer using a 0.7 g / dl methylene chloride solution.
[0044]
In the method of the present invention, the polycarbonate having a melt viscosity of about several thousand poises thus produced is further supplied to the above stirring device in a molten state, and stirring and mixing are continuously carried out in the device to continuously polymerize 20,000. The degree of polymerization is increased to a melt viscosity of ˜30,000 poise, and a polycarbonate having a good optical property [η] of about 0.3 to 0.7 is produced.
[0045]
In this latter polymerization step, the reaction temperature (set temperature in the container) is 120 to 350 ° C., preferably 170 to 300 ° C., the pressure is 10 to 0.1 Torr, preferably 1 to 0.1 Torr, and the reaction time (inside the apparatus) The residence time is preferably about 30 to 120 minutes.
[0046]
【The invention's effect】
According to the apparatus of the present invention, the non-uniformity of the stagnation of the solution in the vicinity of the liquid supply port is prevented, the apparatus is filled with the solution evenly, and the generation of a deteriorated product due to the generation of the gas-liquid interface is suppressed, so that sufficient self Cleanability is realized.
[0047]
In addition, according to the apparatus of the present invention, sufficient self-cleaning performance is realized, so that high-viscosity and high-quality polymer can be produced without polymer deterioration and gel generation even if the operation is continued for a long time. In addition, the cleaning cycle of the apparatus can be lengthened.
[0048]
The apparatus of the present invention is useful in the case of producing a polymer by stirring and mixing a solution having a high viscosity of 100 poise or more, and is suitable for use in a later stage of polymerization.
[0049]
【Example】
Next, the example which manufactures the aromatic polycarbonate which is 1 type of a polycondensation type polymer using the stirring apparatus of this invention is demonstrated. The measurement of the intrinsic viscosity [η] in the examples is as described above.
[0050]
[Example 1]
Bisphenol A and diphenyl carbonate are melt-polymerized, and the resulting polycarbonate having an intrinsic viscosity [η] of 0.35 is supplied in a molten state to a vertical cross-section stirrer shown in FIGS. did. Using the apparatus having the liquid supply port 8 shown in FIG. 3, the polymerization reaction was allowed to proceed at a temperature of 270 ° C. under reduced pressure.
[0051]
Then, the polymer after completion of the reaction was taken out from the liquid outlet 9. In this way, a polycarbonate having a final intrinsic viscosity [η] of 0.5 and a good hue could be continuously produced for about 700 hours.
[0052]
When the inside of the container of the stirring device was disassembled and inspected after completion of the experiment, it was confirmed that there was no dirt such as polymer degradation products and that a good self-cleaning function was maintained.
[Brief description of the drawings]
FIG. 1 is a horizontal sectional view of a specific example of a stirring device of the present invention.
FIG. 2 is a schematic cross-sectional view taken along the line AA ′ of FIG.
FIG. 3 is a schematic cross-sectional view of the apparatus shown in FIGS. 1 and 2 when viewed from the stirring axis direction.
FIG. 4 is a schematic diagram showing the position of a liquid supply port.
FIG. 5 is a schematic diagram showing the position of a liquid supply port.
FIG. 6 is a schematic diagram showing the position of a liquid supply port.
FIG. 7 is a schematic diagram showing the position of a liquid supply port.
FIG. 8 is a schematic diagram showing the position of a liquid supply port.
FIG. 9 is a schematic diagram showing the position of a liquid supply port.
FIG. 10 is a schematic view of a liquid retention distribution in the apparatus cross section.
FIG. 11 is a horizontal sectional view of a specific example of the stirring device of the present invention having a scraper.
12 is a schematic cross-sectional view taken along the line AA ′ of FIG. 11. FIG.
13 is a schematic cross-sectional view of the apparatus shown in FIGS. 11 and 12 as viewed from the stirring axis direction. FIG.
[Explanation of symbols]
1: Container 2, 3: Stirring shafts 4a-4s, 5a-5s: Stirring rotor 6, 7: End plate 8: Liquid supply port 9: Liquid outlet 10: Cylinder 11: Vertically upward 12: Scraper 13: Length of scraper

Claims (5)

Two stirring shafts that are arranged in parallel in a cylindrical container installed substantially horizontally and are synchronously driven to rotate in the same direction are provided side by side, and 90 degrees around each stirring shaft. In a stirrer equipped with a plurality of stirrer rotors that are fixedly shifted and spaced apart in the axial direction and attached to the stirrer shaft, and that has a stirring action, when the liquid supply port to the container is viewed from the outside When the rotation of the stirring shaft is counterclockwise, the starting point is vertically upward from the center of the left stirring shaft, the rotation direction of the stirring shaft is positive, and −45 degrees to +90 degrees (however, −45 degrees and x = 0 Except x = 0, the center of the line connecting the centers of the two stirring axes is 0, the line connecting the centers of the two stirring axes is the x coordinate, and the line perpendicular to the x coordinate is the y coordinate was placed on the container of the end plate corresponding to the range of up to at a) point x = 0 of the coordinate system, the time the rotation of the stirring shaft When around from the center of the right side of the stirring shaft starting from the vertically upward, the direction of rotation of the stirring shaft as positive, excluding the + 90 ° -45 ° (but -45 ° and x = 0, x = 0 is two The point of x = 0 in the xy coordinate system where the line connecting the centers of the two stirring axes is 0, the line connecting the centers of the two stirring axes is the x coordinate, and the straight line perpendicular to the x coordinate is the y coordinate. A stirrer provided on the end plate of the container corresponding to the range up to ( a ).   2. The stirring device according to claim 1, wherein the stirring rotor has a spindle-shaped cross-sectional shape in which the central portion is swollen and both ends are sharp, and when the diameter is D, the radius of curvature is D / √2.   2. The stirring device according to claim 1, wherein a scraper is attached to the tip of the stirring rotor so that an outer surface thereof coincides with an outer peripheral surface of the stirring rotor to form a pseudo-triangular cross section, and a scraper is attached in parallel to the stirring shaft.   A method for producing a polymer, wherein the polycondensate previously polycondensed is further polymerized by the apparatus according to any one of claims 1 to 3.   A polycarbonate obtained by melt polymerization of an aromatic dihydroxy compound and a carbonic acid diester is supplied to the stirring device according to any one of claims 1 to 4, and further melted and stirred under reduced pressure in the device. A method for producing a polycarbonate, comprising polymerizing.

Images