JP3083739B2 - Stirrer and method for producing polycarbonate using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a stirring device. More specifically, the present invention relates to a stirrer suitable for producing polycarbonate and the like and a method for producing polycarbonate.

[0002]

2. Description of the Related Art In general, for the production of polymers, an apparatus having a high mixing performance and a high heat transfer performance and a function of positively preventing stagnation of the polymer is often desired.

Particularly, in the production of polycarbonate often used for optical applications, if a part of the polymer remains in the apparatus, it deteriorates and becomes a decisive problem in quality, and the function of preventing the stagnation of the polymer is extremely important.

In general, in a horizontal stirring device, a polymer easily penetrates between the rotating shaft of the shaft sealing portion and the inner wall of the shaft sealing nozzle, and the sealing mechanism at the portion is a method using a gland packing, an oil seal, or a mechanical method. A method using a seal is well known.

[0005]

However, in this type of conventional apparatus, it was difficult to prevent the stagnation of the polymer in the shaft sealing portion. Especially when handling a high-temperature polymer such as a stirrer for polycarbonate production, the types of gland packing that can be used are limited, and the ability to follow the deflection of the rotating shaft is poor. , Which stays, deteriorates and flows back into the device, causing quality problems or
This caused many troubles due to seizure with the rotating shaft.

On the other hand, the method using an oil seal or a mechanical seal has no adaptability to a high temperature.
It is necessary to install a cooling zone in the shaft sealing nozzle part, the retention of the polymer between the rotation axis of the part and the nozzle inner wall,
It was extremely difficult to prevent deterioration. For the above-mentioned reasons, in the production of polycarbonate, the washing interval of the stirring device has to be shortened in order to maintain the product quality, resulting in an increase in operating costs.

The present invention solves the problem of the method for producing polycarbonate and the like in the conventional stirring device, and can prevent the polymer from staying in the shaft sealing portion of the device and backflow into the device. It is an object to provide a stirring device. Another object of the present invention is to provide an apparatus capable of continuously producing polycarbonate while maintaining product quality at a low operating cost, and a method for producing polycarbonate using the apparatus.

[0008]

That is, the present invention relates to a horizontal stirring device having a single-shaft or multi-shaft rotary shaft, wherein two types of screw-shaped grooves having different conveying directions are provided on the rotary shaft in the shaft sealing portion. And a stirrer provided with a pipe so that liquid can be extracted from the boundary between these grooves.
The present invention also includes a method for producing a polycarbonate using the above-described stirring device.

Hereinafter, the stirring apparatus of the present invention will be described in detail with reference to specific examples.

FIGS. 1 and 2 show a stirrer according to the present invention. FIG. 1 is a longitudinal sectional view and FIG. 2 is a transverse sectional view.

In the present invention, the container is indicated by 1 in the figure. The inner wall of the container 1 has a shape in which two cylindrical walls centered on the rotation shafts 2 and 3 are connected, but the shape is not particularly limited. The polymer inlet is indicated by 4 in the figure, and the polymer outlet is indicated by 5 in the figure.

A plurality of rotation axes are indicated by 2 and 3 in the figure. The number of rotation axes can be appropriately selected. In the figure, two rotating shafts 2 and 3 are supported by bearings in parallel with each other, and each rotating shaft 2 and 3 is driven by a driving source (not shown).
As shown by arrows in the drawing, the motors are driven to rotate in the same rotational direction and at the same rotational speed in synchronization with each other.

In the figure, 6 to 45 are stirring rotors,
The container mirrors are indicated by 54 and 55 in the figure. Shaft seal nozzles installed in the container mirror are indicated by 46 to 49 in the figure.

Here, screw-shaped grooves provided on the two types of rotating shafts having different transport directions are indicated by reference numerals 56 to 63 in the figure, and 60 to 63 in the figure indicate that the polymer is directed outward when viewed from the inside of the container. It has a function of transporting the polymer, and 56 to 59 in the figure have a function of transporting the polymer inward as viewed from the inside of the container. As shown in the figure, these two types of screw-shaped grooves are provided with a screw groove having an outward transfer function inside as viewed from the inside of the container, and a screw groove having an inward transfer function outside as viewed from inside the container. .

Further, polymer vent pipes 50 to 53 are provided at the boundary between the two types of screws.

In such a stirring device, the polymer introduced from the inlet 4 is carried out from the outlet 5. On the other hand, the polymer near the inlet of the shaft sealing nozzle portion inside the container is transported into the shaft sealing nozzle portion by the outward screw groove provided on the rotating shaft, and then, by the inward screw groove, in the opposite direction to the transport direction. Upon receiving the force, the fluid is continuously discharged from the polymer outlet pipes 50 to 53 provided at the boundary between the two screw grooves.

Thus, it is possible to prevent the polymer from staying, deteriorating and flowing backward between the inner wall of the shaft sealing nozzle and the rotating shaft.

The screw groove is the same as that of a conventionally known screw extruder or screw feeder, and the number of spirals is preferably 3 or more.

FIG. 3 shows a detailed view of the inside of the shaft sealing portion. The inner diameter D of the shaft sealing portion is 150 mm, the groove width W is 15 mm, and the groove height H is
8mm, spiral width e = 6mm, clearance δ = 2m
m, helix angle α = 35 degrees, helix number = 3, rotation number = 3r
pm, polymer viscosity = about 4c when 3000 poise
The polymer can be delivered at c / min.

The size of each part of the screw groove, such as clearance, should be narrower when a low-viscosity polymer is stirred, and slightly larger when a high-viscosity polymer is used. Therefore, the clearance of the screw groove on the liquid inlet side is preferably narrower than that on the liquid outlet side.

Incidentally, the screw mechanism of the shaft sealing portion of the present invention comprises:
The apparatus is not limited to the one installed in the apparatus having the shape shown in FIGS. 1 and 2, but may be installed in a conventionally known single-shaft or multi-shaft horizontal stirring apparatus.

The polycarbonate supplied to the stirring device of the present invention preferably has an intrinsic viscosity [η] of 0.24 to 0.35. The final intrinsic viscosity [η] of the polycarbonate produced by the stirrer of the present invention is 0.4 to 0.5. The intrinsic viscosity [η] is measured with a 0.7 g / dl methylene chloride solution using an Ubbelohde viscometer.

The present invention encompasses a method for producing a polycarbonate resin, wherein the polycarbonate obtained by melt-polymerizing an aromatic dihydroxy compound and a carbonic acid diester is further polymerized by the above apparatus.

The aromatic dihydroxy compound is not particularly restricted but includes, for example, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4- Hydroxyphenyl)
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,
Examples thereof include dihydroxyaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, dihydroxyaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide, and dihydroxyaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone. 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 generated aromatic monohydroxy compound 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, and the aromatic monohydroxy compound produced is distilled to obtain polycarbonate.

The present invention is characterized in that the polycarbonate produced by such a method is further polymerized by the above apparatus.

[0028]

As described above, in the shaft seal portion of the stirring device, the rotating shaft provided with two types of screw-shaped grooves having different transport directions is driven and rotated, so that the polymer that has entered the relevant portion is retained, deteriorated, and deteriorated. Without letting it flow back
It can be forced to flow and discharged to the outside.

[0029]

EXAMPLES Bisphenol A and diphenyl carbonate were melt-polymerized to obtain an intrinsic viscosity [η] of 0.3.
5 is supplied to the stirring device of the present invention,
When a polycarbonate resin having a final intrinsic viscosity [η] of 0.5 was produced, a polycarbonate having a good hue was reduced to about 1%.
It could be manufactured continuously for 000 hours.

[0030]

According to the present invention, as described above in detail with reference to the embodiments, the intrusion between the rotating shaft of the shaft sealing portion of the horizontal stirring device and the inner wall of the nozzle, which has been a problem in the past, has occurred. Polymer can be satisfactorily discharged to the outside without stagnation, preventing polymer degradation at the site and backflow into the device, and maintaining product quality without increasing operating costs. This has a remarkable effect that a polymer can be produced continuously and stably. The device of the invention is suitable for polycarbonate.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a specific example of a stirring device of the present invention.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is a detailed view of the inside of a shaft sealing portion.

[Explanation of symbols]

 1: Container 2, 3: Rotating shaft 4: Liquid inlet 5: Liquid outlet 6-45: Stirring rotor 46-49: Shaft sealing part 50-53: Polymer outlet tube 54, 55: Mirror part 56-59: Screw groove part 60 to 63: screw groove D: inner diameter of shaft seal W: groove width H: groove height e: spiral width δ: clearance α: spiral angle

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-304460 (JP, A) JP-A-48-94053 (JP, A) JP-A-47-18058 (JP, A) JP-A 8- 128535 (JP, A) JP 4742583 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01F 7/08

Claims (2)

(57) [Claims] In a horizontal stirring device having a single-shaft or multi-shaft rotary shaft, two types of screw-shaped grooves having different conveying directions are provided on a rotary shaft in a shaft sealing portion, and a boundary between these grooves is provided. A stirrer equipped with a tube so that liquid can be drawn out. 2. A method for producing a polycarbonate, comprising subjecting a polycarbonate obtained by melt-polymerizing an aromatic dihydroxy compound and a carbonic acid diester to further polymerizing by using the apparatus according to claim 1.