JP2002126489A - Agitator and polymer production process using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an agitator in which nonuniformity inflow of a liquid is prevented, generation of deteriorated matter due to formation of a gas-liquid interface is prevented, and also self-cleaning properties are sufficiently improved. SOLUTION: This agitator is provided with two agitation axes 2 and 3 which are placed parallel to each other within a cylindrical vessel 1 installed in a substantially horizontal direction and subjected to synchronous rotary driving in the same direction; and a series of plural rotor sets each consisting of two agitation rotors 4a and 4b and another series of plural rotor sets each consisting of two rotors 5a and 5b, which are used for performing agitation action and fitted to the axes 2 and 3 respectively in such a way that the two agitation rotors 4a and 4b (or 5a and 5b) of every set of each of the series are fixed to the axis 2 (or 3) so as to be deviated by 90 deg. from each other around the axis 2 (or 3) and all the rotors 4a and 4b (or 5a and 5b) of each of the series are arranged at prescribed intervals in the axial direction; wherein a liquid supply port 8 for supplying a liquid to the cylindrical vessel 1, when the upstream side of the vessel 1 is viewed from the outside (as shown in the figure), is formed in the end plate or cylinder of the vessel 1 at a position being within the range or -45 deg. to +90 deg. with, as the origin, a point positioned vertically above the center of the agitation axis 2 on the left side when the rotational direction of each of the axes 2 and 3 is counterclockwise (or the agitation axis 3 on the right side when the rotational direction of each of the axes 2 and 3 is clockwise) and also, with the rotational direction of the agitation axis 2 (or 3) as the positive direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD 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 a high-viscosity polycondensate such as saturated and unsaturated polyesters, polyethers, polyamides, polycarbonates and the like using this apparatus.

[0002]

2. Description of the Related Art Generally, a stirrer having a high mixing performance and a high heat transfer performance and a function of positively preventing stagnation of a polymer, that is, a self-cleaning function, is desired as an apparatus for producing a synthetic polymer. There are many.

In particular, in order to produce a polymer often used for 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 device for treating a viscous substance having particularly high adhesiveness.

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 the shafts, and a gap between the stirring rotors and a gap between the stirring rotor and the inner wall of the container are slightly maintained. There is a device that mechanically prevents 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 provided with a plurality of stirring shafts disposed in a container and driven to rotate in synchronization with each other, and a plurality of stirring rotors fixed to the respective stirring shafts to perform a stirring action. The stirring rotor is attached at an interval in the axial direction, and a scraper having a length substantially corresponding to the interval is attached to a tip portion of the stirring rotor in parallel with the stirring shaft.

In this device, a self-cleaning action is performed simultaneously with the stirring action. That is, the tip ridge of each stirring rotor moves close to the inner wall of the container, and the curved peripheral surfaces of the stirring rotor of one stirring shaft and the stirring rotor of the other stirring shaft have their tips close to each other. Moving,
Self-cleaning is performed by the relative movement of the stirring rotor planar side surface and the opposing planar side surface of the stirring rotor in close proximity.

[0007]

However, in a conventional apparatus having such a self-cleaning function,
Usually, a liquid supply port is provided at the bottom of the container, and there is a disadvantage that the flow of the liquid to be treated becomes unstable near the supply port. Therefore, it is difficult to uniformly wet the stirring rotor near the liquid supply port with the supply liquid, and there has been a problem that a gas-liquid interface is generated on the surface of the stirring rotor and a deteriorated product is generated near the interface.

[0008] In particular, this tendency is remarkable when a high-viscosity fluid of a polymer is stirred and mixed, and a boundary between a gas phase and a liquid phase is generated near the supply port, and the polymer is easily deteriorated near the interface, If the self-cleaning property is insufficient, the cleaning interval of the apparatus must be shortened in order to maintain product quality, which has been a major factor in increasing the operating cost.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the conventional stirrer, and to improve the self-cleaning property and to obtain linear saturated and unsaturated polyesters, polyethers and polyamides. An apparatus capable of producing a polycondensate such as polycarbonate and polycarbonate, and a method for continuously producing a high-quality polymer at a low operating cost using the apparatus.

[0010]

SUMMARY OF THE INVENTION The present invention provides two stirring shafts which are disposed in parallel in a substantially horizontally installed cylindrical container and are synchronously driven to rotate in the same direction. With
In a stirrer having a plurality of stirring rotors that are fixed to be shifted by 90 degrees around the axis of each stirring shaft and that are attached to the stirring shaft and are spaced apart in the axial direction and have a stirring action and perform a liquid supply port to the container, When the rotation of the stirring shaft is counterclockwise when the container is viewed from the outside, the starting point is vertically upward from the center of the left stirring shaft, and the rotation direction of the stirring shaft is positive, from -45 degrees to +90 degrees ( (Excluding -45 degrees), placed on the end plate or cylinder of the container corresponding to the range up to -45 degrees, and when the rotation of the stirring shaft is clockwise, the starting point is vertically upward from the center of the stirring shaft on the right side. With the rotation direction as positive, from -45 degrees to +
A stirrer characterized by being installed on a head plate or a cylinder of the container corresponding to a range up to 90 degrees (excluding -45 degrees).

The present invention is also a method for producing a polymer, characterized in that a polycondensate which has been polycondensed in advance is further polymerized by the apparatus of the present invention. In the present invention, the polycarbonate obtained by melt-polymerizing the aromatic dihydroxy compound and the carbonic acid diester is supplied to the stirring device of the present invention, and is further polymerized by melt-stirring under reduced pressure in the device. And a method for producing a polycarbonate.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a specific example of a stirring device of the present invention will be described in detail with reference to the drawings.

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 diagram of a cross section of the apparatus of FIGS. 1 and 2 as viewed from a stirring axis direction.

(Container) In the stirring apparatus of the present invention, the container 1 is installed substantially horizontally, and the inner wall of the container 1 is connected to two cylindrical walls centered on the stirring shaft 2 and the stirring shaft 3, respectively. It has a cocoon-shaped cross section of such a shape. In addition, although the cocoon shape is suitable for the cross-sectional shape of the container 1, it is not limited to this.

(Stirring shaft) In the container 1, there are provided two stirring shafts 2, 3 extending substantially horizontally in the longitudinal direction of the container, and these two stirring shafts 2, 3 are parallel to each other. The stirring shafts 2 and 3 are rotatably driven by a drive source (not shown) in the same rotation direction and at the same rotation speed as indicated by arrows in the drawing.

(Stirring Rotor) A plurality of stirring rotors are fixed to the stirring shafts 2 and 3 at predetermined intervals along a plane orthogonal to the stirring shaft. Each stirring rotor is
As shown in FIGS. 3 to 7, it is formed in a thick plate shape having a spindle-shaped cross section with a bulged central portion and sharp ends at both ends, but the shape can be appropriately selected. Further, the number of stirring rotors fixed to each stirring shaft can be appropriately selected, but it is appropriate to arrange the stirring rotors substantially uniformly over the entire stirring shaft. FIG.
If the diameter of the rotor is D as shown by, the radius of curvature of the rotor is preferably D / √2.

As shown in FIGS. 1, 2, 11, and 12, the stirring rotor fixed to each stirring shaft is separated from the inner wall of the cylinder 1 of the container 1 by a small gap in accordance with the rotation angle position. Alternatively, the dimensions are selected so as to be able to face the stirring rotor fixed to the adjacent and adjacent stirring shaft.

That is, a plurality of (19 in FIG. 1 and FIG. 2) stirring rotors 4 are arranged on one stirring shaft 2 at predetermined intervals.
a, 4b, 4c,... 4s are fixed. These stirring rotors are attached to the stirring shaft 2 along a plane orthogonal to the stirring shaft. These stirring rotors are opposed to the corresponding stirring rotors 5a, 5b, 5c,... 5s fixed to the first cylindrical wall or the other stirring shaft 3 with a slight gap depending on the rotation angle position. Its dimensions are selected to obtain.

On the other hand, a plurality of stirring shafts 3 (FIG. 1,
In FIG. 2, the same number of stirring rotors 5a, 5b, 5c,... 5s as the stirring rotor of the stirring shaft 2 (19 pieces) are fixed. Each stirring rotor is located at the same axial position corresponding to the corresponding stirring rotor of the opposing stirring shaft 2, and is attached to the stirring shaft 3 in such a manner that each phase is shifted by 90 degrees with respect to the corresponding stirring rotor. Have been.

Each of the stirring rotors has a pointed end which can be opposed to the inner wall of the cylinder of the container 1 or the corresponding stirring rotor with a small gap depending on the rotational angle position. Furthermore, the side faces are respectively opposed to adjacent stirring rotors with a slight gap in the axial direction. The stirring rotor fixed to the stirring shaft 2 and the stirring rotor fixed to the stirring shaft 3 are respectively located in the same axial direction corresponding to the other stirring rotor, and each have a phase of 90 with respect to the corresponding stirring rotor. It is attached to the stirring shaft with a staggered shape. Furthermore, the side surface of each stirring rotor is opposed to the adjacent stirring rotor with a slight gap in the axial direction.

(Scraper) In the apparatus shown in FIGS. 1 to 3, each stirring rotor is not provided with a scraper.
As in the apparatus shown in FIG. 13, a scraper may be provided at the tip of each stirring rotor, and it is often preferable to use a scraper. When a scraper is provided at the tip of the stirring rotor, the self-cleaning property can be further improved.

The scraper is preferably attached to the tip of the stirring rotor in parallel with the stirring shaft. Its shape is
It is preferable that the outer surface coincides with the outer peripheral surface of the stirring rotor to form a pseudo-triangular cross section as shown by 12 in FIG. Further, it is preferable that the length 13 of the scraper is substantially equal to the interval between the stirring rotors as shown in FIG.

(Liquid Outlet) Usually, the liquid outlet 9 is often attached to the lower part of the cylinder 10 of the container 1.

(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 its position is selected as follows.

In the present invention, the liquid supply port 8 to the container 1
Is provided at a position shown by oblique lines in FIGS. FIG. 4-
FIG. 7 is a schematic diagram illustrating the position of the liquid supply port when the stirring device of the present invention is viewed from the outside.

In the stirring apparatus of the present invention, the solution to be treated is introduced into the vessel 1 through a liquid supply port provided in the end plate 6 or the cylinder 10 and provided in a hatched area in FIGS.
When the stirring shafts 2 and 3 are rotated and driven, the respective stirring rotors move and are sufficiently stirred, and then taken out from the liquid outlet 9.

The most characteristic feature of the stirring apparatus of the present invention is that a liquid supply port is provided at a specific position where a solution supply port is not provided in the conventional apparatus.

That is, when the container is viewed from the outside,
As shown in FIGS. 4 and 5, when the rotation of the stirring shaft is counterclockwise, the liquid supply port 8 is defined as a starting point vertically 11 from the center of the left stirring shaft 2 and the rotation direction of the stirring shaft is defined as positive. , -4
The end plate 6 of the container corresponding to the range of 5 degrees to +90 degrees (FIG.
On the cylinder 10 (shown in FIG. 5).

When the rotation of the stirring shaft is clockwise as shown in FIGS. 6 and 7, the liquid supply port 8 starts from vertically above the center of the right stirring shaft. The most characteristic feature is that the container is installed in the range projected on the end plate 6 (shown in FIG. 6) or the cylinder 10 (shown in FIG. 7) of the container, which corresponds to the range of -45 degrees to +90 degrees. Is what you do. 8 and 9 are vertical sectional views of the device showing the liquid supply port 8. FIG.

The present invention relates to a horizontal type stirring apparatus having a structure shown in FIG.
It is based on the finding that the second quadrant indicated by 0 has the lowest solution retention amount inside the stirrer.

That is, as shown in FIG. 10, a horizontal stirrer generally has its rotation direction corrected starting from a point on a cylinder vertically above the stirring shaft mainly due to the influence of gravity and the rotational movement of the stirring rotor. Then, in the second quadrant shown in FIG. 10 which is above the horizontal plane passing through the center of the stirring shaft of the cylinder of the device, the solution retention amount inside the stirring device is reduced most. This is based on the finding that the non-uniformity of the staying amount in the inside can be eliminated.

In the conventional apparatus, when the rotation direction of the stirring shaft is counterclockwise, if the xy coordinate system is taken as shown in FIG. 10, the range of y ≧ 0 (the first quadrant and the second quadrant) is obtained. y <
In the range of 0 (quadrants III and IV), the amount of retained polymer is smaller when y ≧ 0 due to the influence of gravity.
Further, the range of x ≧ 0 (the quadrants I and IV) and x <0
When compared with the range (quadrants II and III), the rotation direction is counterclockwise, so that the range x <0 (the
Quadrants I and III) have low polymer retention.

Therefore, in the coordinate system shown in FIG.
Since the amount of retained polymer in the range of ≧ 0 and x <0 (quadrant II) was the smallest, self-cleaning properties could not be maintained.

However, according to the present invention, FIGS.
As described in detail above, looking at the head plate from the outside of the container, when the rotation of the shaft is counterclockwise, the starting point is the vertical upper part 11 of the stirring shaft on the left side of the head plate 6 of the container, and the rotation direction is positive. 4
Within the range of 5 ° to 90 °, when the rotation of the shaft is clockwise, the starting point is the vertical upper part 11 of the stirring shaft on the right side of the end plate 6 of the container, and when the rotation direction is positive, the rotation is −45 ° to 90 °. By providing the liquid supply port 8 within the range, the stirring rotor near the liquid supply port, which has been difficult to wet up to now, can be sufficiently wetted.

Since the non-uniform solution stagnation in the vicinity of the liquid supply port in the apparatus is eliminated, the liquid is filled evenly in the apparatus, and the vicinity of the liquid supply port in which there has been no reliable solution. The self-cleaning property of the stirring rotor has been improved,
Even if the operation is continued for a long time, it is possible to produce a high-quality polymer free of polymer deterioration and generation of a gel or the like.

In this case, the position of the liquid supply port 8 is preferably as close to the end plate 6 as possible. Preferably, the structure in which the solution to be treated can be directly supplied to the stirring rotor near the end plate 6 is more self-cleaning. Good nature.

(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.

That is, the present invention provides a method for producing a polymer, characterized in that a polycondensate which 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, polycarbonates, and the like.

The present invention can be applied to the melt polymerization of aromatic polycarbonate among the above-mentioned saturated and unsaturated polymers. That is, the present invention provides a polycarbonate obtained by melt-polymerizing an aromatic dihydroxy compound and a carbonic acid diester, preferably having an intrinsic viscosity [η] of 0.2 to 0.3.
A method of producing a polycarbonate having a higher degree of polymerization by further melt-polymerizing about 5 polycarbonates under reduced pressure by the above-mentioned stirring device.

Examples of the aromatic dihydroxy compound used herein include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, and 2,2-bis (4-hydroxyphenyl). Phenyl)
Octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxy-t-
Bis (hydroxyaryl) alkanes such as butylphenyl) propane; bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclopentane and 1,1-bis (hydroxyphenyl) cyclohexane; Dihydroxyaryl ethers such as 4,4'-dihydroxydiphenyl ether, dihydroxyaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, dihydroxyaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulphoxide, and 4,4'- Dihydroxyaryl sulfones such as dihydroxydiphenyl sulfone are used. Particularly, 2,2-bis (4-hydroxyphenyl) propane is preferable.

Examples of the carbonic acid diester include optionally substituted esters such as an aryl group having 6 to 10 carbon atoms and an aralkyl group. Specific examples include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, and the like.

The melt polymerization reaction between the aromatic dihydroxy compound and the carbonic acid diester is carried out by distilling the aromatic monohydroxy compound formed by stirring under heating in an inert gas atmosphere as is conventionally known. Will be The reaction temperature is usually in the range of 120 to 350 ° C., and in the late stage of the reaction, the degree of reduced pressure of the system is increased to 1 to 0.1 Torr to facilitate the distillation of the aromatic monohydroxy compound produced, thereby increasing the intrinsic viscosity [η]. Is about 0.2 to 0.35.

Here, the intrinsic viscosity [η] is 0.7
g / dl in a methylene chloride solution measured with an Ubbelohde viscometer.

In the method of the present invention, the polycarbonate thus produced having a melt viscosity of about several thousands poise is further supplied in a molten state to the above-mentioned stirring device, and is continuously polymerized by stirring and mixing in the device. As a result, the degree of polymerization is increased to a melt viscosity of 20,000 to 30,000 poise, and a polycarbonate having good optical properties [η] of about 0.3 to 0.7 is produced.

In the latter polymerization step, the reaction temperature (set temperature in the vessel) is 120 to 350 ° C., preferably 170 to 350 ° C.
300 ° C., pressure 10 to 0.1 Torr, preferably 1
To 0.1 Torr, reaction time (residence time in the apparatus)
Is preferably employed for about 30 to 120 minutes.

[0046]

According to the apparatus of the present invention, the non-uniform stagnation of the solution in the vicinity of the liquid supply port is prevented, the solution is evenly filled in the apparatus, and the generation of degraded products due to the generation of the gas-liquid interface is prevented. Suppressed and sufficient self-cleaning property is realized.

According to the apparatus of the present invention, a sufficient self-cleaning property is realized. As a result, even if the apparatus is operated for a long time, the polymer is not deteriorated and no gel is generated. Manufacturing becomes possible, and the cleaning cycle of the apparatus can be lengthened.

The apparatus of the present invention is useful for stirring and mixing a solution having a high viscosity of 100 poise or more and producing a polymer, and is suitable for use in a later stage of polymerization.

[0049]

Next, an example of producing an aromatic polycarbonate which is a kind of polycondensation polymer using the stirring apparatus of the present invention will be described. The measurement of the intrinsic viscosity [η] in the examples is as described above.

Example 1 Bisphenol A and diphenyl carbonate were melt-polymerized, and the obtained polycarbonate having an intrinsic viscosity [η] of 0.35 was placed horizontally in a molten state as shown in FIGS. The mixture was supplied to a stirring device having a cocoon-shaped cross section. Using an apparatus having a liquid supply port 8 shown in FIG.
The polymerization reaction was allowed to proceed at 270 ° C. under reduced pressure.

After the completion of the reaction, the polymer 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.

After completion of the above experiment, the inside of the container of the stirring device was disassembled and inspected. As a result, it was confirmed that there was no stain such as polymer deterioration 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 sectional view taken along the line A-A ′ of FIG. 1;

FIG. 3 is a schematic view of a cross section of the apparatus shown in FIGS. 1 and 2 as viewed from a stirring axis direction.

FIG. 4 is a schematic diagram showing a position of a liquid supply port.

FIG. 5 is a schematic diagram showing a position of a liquid supply port.

FIG. 6 is a schematic diagram showing a 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 a position of a liquid supply port.

FIG. 9 is a schematic diagram showing a position of a liquid supply port.

FIG. 10 is a schematic view of a liquid retention distribution in a cross section of the apparatus.

FIG. 11 is a horizontal sectional view of a specific example of the stirring device of the present invention having a scraper.

FIG. 12 is a schematic cross-sectional view taken along line A-A ′ of FIG. 11;

FIG. 13 is a schematic view of a cross section of the device shown in FIGS. 11 and 12 viewed from the direction of the stirring axis.

[Explanation of symbols]

 1: Container 2, 3: Stirring shaft 4a-4s, 5a-5s: Stirring rotor 6, 7, End plate 8: Liquid supply port 9: Liquid outlet 10: Cylinder 11: Vertically up 12: Scraper 13: Length of scraper

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toru Sawaki 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi Prefecture Teijin Co., Ltd. Inside the Iwakuni Research Center (72) Inventor Tsuyoshi Muraoka 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi Prefecture Teijin Shares 4G035 AB39 AE13 AE19 4G037 DA15 EA03 4G078 AA02 AB11 BA01 BA07 BA09 CA02 CA09 CA12 CA17 DA16 DB03 EA10 4J029 AA09 AB04 BB11 BD10 BF03 BH02 KE05 LA07 LA08 LA10 LA11

Claims (5)

[Claims] 1. Two stirring shafts arranged in parallel in a substantially horizontally installed cylindrical container and synchronously driven to rotate in the same direction are provided side by side. In a stirrer having a plurality of stirring rotors which are fixed at 90 degrees around an axis and are attached to an agitating shaft at an interval in an axial direction and have a stirring action, a liquid supply port to the container is provided outside the container. When the rotation of the stirring shaft is counterclockwise as viewed from above, the starting point is vertically upward from the center of the left stirring shaft, and the rotation direction of the stirring shaft is positive and the rotation direction of the stirring shaft is -45 degrees to +90 degrees (-45 degrees).
(Excluding degrees) on the end plate or cylinder of the container corresponding to the range up to the right, and when the rotation of the stirring shaft is clockwise, start from the center vertically above the stirring shaft on the right and start the rotation direction of the stirring shaft. A stirrer characterized by being installed on a head plate or a cylinder of the container corresponding to a range from -45 degrees to +90 degrees (excluding -45 degrees) as positive. 2. The stirrer according to claim 1, wherein the stirring rotor has a spindle-shaped cross-sectional shape with a bulged central portion and sharp ends, and a radius of curvature is D / √2 when the diameter is D. 3. The stirring device according to claim 1, wherein an outer surface of the stirring rotor has a pseudo-triangular cross section at the tip end thereof, and a scraper is attached in parallel with the stirring shaft. 4. A method for producing a polymer, wherein a polycondensate that has been polycondensed in advance is further polymerized by the apparatus according to claim 1. 5. A polycarbonate obtained by melt-polymerizing 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 melt-stirred under reduced pressure by the device. A process for producing a polycarbonate.