JPH1076149A - Stirrer and method for producing polymer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a condensation polymerization product of a high quality saturated and unsaturated polyester or the like by arranging a rotor for feeding a liquid to a liquid outlet side in a vessel to improve self-cleaning property in the liquid outlet side. SOLUTION: The rotor having liquid feed action is mounted at a hatched part X of the liquid outlet side of a stirring device. The rotor having liquid feed action is preferably screw-like and the helical angle α of the screw is preferably 25±10 deg. so that the flow is smoothly changed to improve the self- cleaning property. The stirring device is suitable for stirring a high viscosity solution of the condensation polymerization based polymer. Since the lowering of the resident quantity of the polymer in the vicinity of the liquid outlet port is prevented by this way and the polymer is sufficiently supplied to the stirring rotor and an end plate 7 near the liquid outlet, the self-cleaning property is improved. Then, the generation of air-liquid interface is prevented, the degradation of the polymer and the generation of a gel are eliminated and the high quality polymer is produced.

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 liquid stirring device having a self-cleaning function.
Further, the present invention relates to a method for producing a linear high-viscosity polycondensate such as polyester, polyether, polyamide, polycarbonate, etc., 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 function has been proposed as a device for treating a viscous substance having particularly high adhesiveness.

In such a stirrer having a self-cleaning function, two or more stirring shafts are provided in a container, and the stirrer rotors mounted on these stirrers and the stirrer rotor and the inner wall of the stirrer are maintained while maintaining a small gap. By moving, it is a device that tries to prevent as much as possible the formation of deposits on the inner wall of the container, as a specific device,
For example, a stirrer described in JP-A-63-232828 is known.

That is, the publication discloses a plurality of stirring shafts arranged 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. A stirrer in which 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. Have been.

[0006]

However, this type of apparatus is generally provided with a stirring rotor having only a stirring action which does not have a self-liquid-feeding property because it is necessary to have both the residence time and the self-cleaning property. Since the liquid outlet for the solution to be treated is provided at the bottom of the container, the polymer is discharged at the liquid outlet, and the amount of retained polymer is reduced. Sufficient polymer was not supplied to the end plate, resulting in a decrease in self-cleaning properties.

This tendency is particularly remarkable when a high-viscosity polymer is stirred and mixed. Even when the main body has excellent self-cleaning properties, a boundary between a gas phase and a liquid phase occurs near the liquid outlet, If the polymer easily deteriorates at the interface and the self-cleaning property is insufficient, the cleaning interval of the apparatus must be shortened in order to maintain the product quality, which has been a major factor in increasing the operating cost. .

The main object of the present invention is to solve the problems of the conventional stirring apparatus, and to improve the self-cleaning property at the liquid outlet side, to obtain high-quality saturated and unsaturated polyesters. An object of the present invention is to provide an apparatus capable of producing a polycondensate such as polyether, polyamide, and polycarbonate. Another object of the present invention is to provide a method for producing a polymer at a low operating cost while maintaining the product quality using the apparatus.

[0009]

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
A stirring device comprising a plurality of stirring rotors on each stirring shaft, wherein a rotor having a liquid sending action is disposed at a liquid outlet in the container.

[0010] The present invention is also a method for producing a polymer, characterized in that a polycondensate which has been previously polycondensed is further polymerized by the apparatus of the present invention.

[0011]

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, FIG. 2 is a vertical sectional view of AA ′ in FIG. 1, and FIG. 3 is a transverse sectional view of the device.

(Container) In the stirring device of the present invention, the container 1 is installed substantially horizontally, and the sectional shape of the container 1 is not particularly limited. Preferably, the inner wall of the container 1 has a cocoon-shaped cross section in which two cylindrical walls centered on the stirring shaft 2 and the stirring shaft 3, respectively, are connected.

(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. Each of the stirring shafts 2 and 3 is driven by a drive source (not shown) so as to be rotationally driven in the same rotational direction in the same rotational direction as shown by an arrow in the drawing, or at a different rotational speed in synchronization with each other. Has become.

(Stirring rotor) A plurality of stirring rotors are fixed to each stirring shaft 2 and 3 at predetermined intervals along a plane orthogonal to the stirring shaft. Such a stirring rotor has only a stirring function and does not have a liquid sending function. It is preferable that the stirring rotor be attached to the stirring shaft at an interval of 90 ± 10 degrees around the axis with respect to the stirring shaft and spaced apart in the axial direction.

As shown in FIG. 3, each stirring rotor has a spindle-shaped cross-sectional shape with a bulged central portion and sharp ends, and when the diameter is D, the radius of curvature is preferably D / √2. The shape can be appropriately selected. 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.

As shown in FIG. 3, the stirring rotors fixed to the respective stirring shafts are separated from each other by a slight gap in accordance with the rotation angle position thereof, with the inner wall of the container 1 or the adjacent adjacent stirring rotor. The dimensions are selected so that they can face the stirring rotor fixed to the shaft.

That is, a plurality of (14 in FIG. 1) stirring rotors 4a, 4a are arranged on one stirring shaft 2 at a predetermined interval.
4n 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,... 5n 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, the stirring shaft 3 is similarly provided with a plurality of stirring rotors 5 (the same number as 14 stirring rotors of the stirring shaft 2 in FIG. 1).
a, 5b, 5c,... 5n are fixed.

Each stirring rotor has a stirring shaft 2 opposed to each other.
Corresponding to the corresponding stirring rotors, and are attached to the stirring shaft 3 in such a manner that their phases are shifted by about 90 degrees with respect to the corresponding stirring rotors.

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 about the corresponding stirring rotor. It is attached to the stirring shaft in the axial direction shifted by 90 degrees. Further, the side surface of each stirring rotor is opposed to the adjacent stirring rotor with a slight gap in the axial direction.

(Liquid Supply Port, Liquid Outlet) Normally, the liquid supply port 8 is attached to the peripheral wall (shell) 1 near the end plate 6, and its position is not particularly limited. It is more preferable to approach the end plate 7 on the side.

On the other hand, the liquid outlet 9 is usually attached to the lower part of the peripheral wall (shell) 1 of the container 1.

In the stirring apparatus of the present invention, the solution to be treated is introduced into the container 1 from the solution supply port 8, and the stirring shafts 2, 3 are rotationally driven while moving to the outlet side due to the head difference. After being sufficiently stirred by the movement of each stirring rotor, the liquid is taken out from the liquid outlet 9.

(Self-cleaning) In this apparatus, self-cleaning is performed simultaneously with the stirring operation. That is, each part in the container 1 is self-cleaned by the pointed edge line of each stirring rotor moving close to each other. Further, the curved peripheral surfaces of the stirring rotor of one stirring shaft and the stirring rotor of the other stirring shaft are self-cleaned by their tips moving close to each other. Further, the planar side surfaces of the stirring rotor and the planar side surfaces of the stirring rotor opposed thereto move relatively close to each other, so that they are also self-cleaned.

However, even with such a stirrer intended for the self-cleaning function, the polymer is discharged from the liquid outlet 9, and the amount of retained polymer in the vicinity of the liquid outlet 9 is reduced. The near stirring rotor and the end plate on the liquid outlet side have a disadvantage that it is difficult to completely wet with the polymer, a gas-liquid interface is generated, and a degraded substance is generated near the interface, so that the self-cleaning property is significantly reduced. .

According to the present invention, the disadvantage of the conventional stirring device can be solved by disposing a rotor having a liquid sending function on the liquid outlet side.

In the stirring apparatus of the present invention, a rotor having a function of feeding liquid is disposed at the liquid outlet side in the vessel, which has not been installed in this type of apparatus, and reaches the end plate on the liquid outlet side. The greatest feature is that the self-cleaning property of the liquid outlet side rotor and the liquid outlet side end plate is improved by increasing the amount of the polymer. The liquid outlet side refers to a hatched portion indicated by x in FIGS.

That is, in the stirring apparatus of the present invention, the rotor having the liquid feeding action exemplified in FIG. 4 is installed in the hatched portion indicated by x in FIGS. 1 and 2, thereby improving the self-cleaning property of the portion. Things. In the present invention, at least the rotor adjacent to the head plate on the liquid outlet side needs to be a rotor that performs a liquid sending action. FIG. 5 shows an example in which a rotor that actually performs a liquid feeding operation is attached to the liquid outlet side.

Conventionally, since the stirring rotor at the liquid outlet has no liquid sending property, the amount of polymer retained in the stirring rotor at the liquid outlet and the end plate on the liquid outlet side is reduced. Although the self-cleaning was not sufficient, the stirring rotor in this part had a liquid sending function, which increased the amount of polymer retained in the stirring rotor and the end plate, improved the wettability of the polymer, and improved the self-cleaning. It can also maintain the nature.

It is preferable that the rotor that performs the liquid feeding action has a screw (spiral) shape. The screw preferably has a helical angle α of 25 ± 10 degrees as shown in FIG. By using such a helical angle, the flow changes smoothly, and the self-cleaning property is improved.

It is also preferable to provide a notch in a part of the screw. The reason for this is not clear, but it is presumed that if the screw has a notch, the polymer will slip through and promote the kneading effect. It is preferable to provide one or more such notches in one pitch of the screw.
As the notch size, the diameter of the screw is D
When a is preferably projected area in the axial direction of the one notch is less than D ^2/8.

[0032] Such a screw-based rotor having a liquid-feeding action may be formed in an integral shape.
A single-piece screw may be formed by stacking slices in the direction perpendicular to the axis at a thickness h of 0.03 <h / D <0.1, and in the latter case, in a range of 5 to 60 degrees. May be stacked while shifting the phase. By laminating the layers out of phase, a screw having a notch can be formed.

(Scraper) As shown in FIG. 6, when a scraper is provided at the tip of the stirring rotor, the self-cleaning property is further improved. The scraper can be attached to the tip of the stirring rotor in a pseudo-triangular cross section with an outer surface coinciding with the outer peripheral surface of the stirring rotor and parallel to the stirring shaft.

(Method for Producing Polymer) The stirring apparatus of the present invention is an apparatus suitable for stirring a high-viscosity solution of a polycondensation polymer, and includes, for example, saturated and unsaturated polyesters, polyethers, polyamides, and polycarbonates. Suitable for manufacturing. Therefore, the present invention includes a method for producing a polymer, characterized in that a polycondensate that has been previously polycondensed is further polymerized by the apparatus of the present invention.

As specific examples of the saturated and unsaturated polymers,
The present invention is also applicable to melt polymerization of such a polymer. Therefore, the present invention provides a polycarbonate obtained by melt-polymerizing an aromatic dihydroxy compound and a carbonic acid diester, preferably a polycarbonate having an intrinsic viscosity [η] of about 0.2 to 0.35, under reduced pressure by the above-described stirring device. A method for producing a polycarbonate having a higher degree of polymerization by further polymerizing under the following conditions is included.

As the aromatic dihydroxy compound used herein, for example, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 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, 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 / d
1 measured with a Ubbelohde viscometer using 1 methylene chloride solution.

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 the mixture is continuously stirred and mixed in the device to continuously polymerize. 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.

[0041]

According to the present invention, the provision of the rotor having a liquid sending function on the liquid outlet side prevents a decrease in the amount of retained polymer in the vicinity of the liquid outlet. And a self-cleaning property is improved. Therefore, generation of a gas-liquid interface is prevented, and even if the operation is continued for a long time, there is no deterioration of the polymer and no gel is generated, so that a high quality polymer can be produced. Further, it is possible to lengthen the cleaning cycle of the apparatus.

Further, according to the method of the present invention, it is possible to continuously produce a polymer while maintaining product quality at a low operating cost. The stirring 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.

[0043]

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 in a cocoon shape as shown in FIG. The mixture was supplied to a stirrer having a cross section, and the polymerization reaction was allowed to proceed at a temperature of 270 ° C. under reduced pressure. With this apparatus and conditions, 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 deteriorated polymer, and that a good self-cleaning function was maintained.

Example 2 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 in a cocoon shape as shown in FIG. The mixture was supplied to a stirrer having a cross section, and the polymerization reaction was allowed to proceed at a temperature of 270 ° C. under reduced pressure. With this apparatus and conditions, a polycarbonate having a final intrinsic viscosity [η] of 0.5 and a favorable hue could be continuously produced for about 800 hours.

Example 3 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 in a cocoon shape as shown in FIG. The mixture was supplied to a stirrer having a cross section, and the polymerization reaction was allowed to proceed at a temperature of 270 ° C. under reduced pressure. With this apparatus and conditions, a polycarbonate having a final intrinsic viscosity [η] of 0.5 and a good hue could be continuously produced for about 700 hours.

After the 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 degraded polymer 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 the stirring device of the present invention.

FIG. 2 is a schematic cross-sectional view taken along the line A-A 'of FIG.

FIG. 3 is a cross-sectional view of FIG.

FIG. 4 is a specific example of a stirring rotor that performs a liquid feeding operation.

FIG. 5 is a specific example of a stirring device to which the stirring rotor of FIG. 4 is attached.

FIG. 6 is a cross-sectional view of a stirring device provided with a scraper on a stirring rotor that performs a stirring action.

FIG. 7 is a cross-sectional view of an apparatus equipped with a stirring rotor having a liquid feeding action, in which a screw having a thickness is stacked at a predetermined phase around a stirring shaft.

8 is a cross-sectional view of the device of FIG.

[Explanation of symbols]

 1: Container 2, 3: Stirring shaft 4a-4n, 5a-5n: Stirring rotor 6, 7, End plate 8: Liquid supply port 9: Liquid outlet x: Liquid outlet side

Continued on the front page (72) Inventor Takeshi Muraoka 2-1 Hinodecho, Iwakuni-shi, Yamaguchi Prefecture Teijin Limited Iwakuni Research Center

Claims (8)

[Claims] 1. Two stirring shafts arranged in parallel and synchronously driven to rotate in the same direction are provided side by side in a cylindrical container placed substantially horizontally. A stirring device comprising a plurality of stirring rotors, wherein a rotor having a function of feeding liquid is disposed on a liquid outlet side in the container. 2. The apparatus according to claim 1, wherein the rotor that performs the liquid feeding action is a screw (spiral). 3. The apparatus according to claim 2, wherein the screw has a helical angle α of about 25 ° ± 10 °. 4. A stirring rotor is provided around the stirring shaft at 90 ±
2. The apparatus according to claim 1, wherein the apparatus is attached to the stirring shaft at an axial distance of 10 degrees. 5. The stirring rotor according to claim 1, wherein the agitating rotor has a spindle-shaped cross-sectional shape in which a central portion is bulged and both ends are sharp, and a radius of curvature is D / √2 when a diameter is D. Equipment. 6. The apparatus according to claim 1, wherein a scraper having a pseudo-triangular cross section whose outer surface coincides with an outer peripheral surface of the stirring rotor is attached to a tip end of the stirring rotor in parallel with the stirring shaft. 7. A method for producing a polymer, comprising polymerizing a polycondensate which has been polycondensed in advance by the apparatus according to claim 1. Description: 8. 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 6, and melt-stirred under reduced pressure in the device. A process for producing a polycarbonate.