JP2001294657A - Apparatus for producing aromatic polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for efficiently producing a polycarbonate resin containing a small amount of a gel and excellent even ion color tone by a transesterification method. SOLUTION: This apparatus comprises one or more vertical type agitated tanks and one or more horizontal type reactors arranged in series and is used in a method for subjecting an aromatic dihydroxy compound and an aromatic carbonic diester to transesterification and continuously producing the aromatic polycarbonate. A horizontal type uniaxial reactional vessel is equipped with an agitating element comprising end disks 9 and 9' and plural hollow disks 11 arranged between the end disks 9 and 9' connected and fixed at a prescribed interval with agitating blades 13 tilted or curved in the direction opposite to the rotative direction and the central parts of the end disks 9 and 9' supported with rotating shafts 8 and 8' in at least one of the horizontal type reactional vessels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for producing an aromatic polycarbonate, and more particularly to an apparatus for producing an aromatic polycarbonate having an improved gel and color tone by a transesterification method.

[0002]

2. Description of the Related Art Polycarbonates obtained from the interfacial polycondensation of aromatic dihydroxy compounds and phosgene are widely used for various purposes due to their excellent mechanical and thermal properties, but use toxic phosgene. However, the use of methylene chloride as a solvent has many problems such as environmental destruction. In recent years, transesterification methods that do not use methylene chloride or phosgene have been spotlighted, but polycarbonate resins obtained by the transesterification method are subject to long-term heat histories at high temperatures, resulting in many gels and poor color tone. No good was obtained. For this reason, the polycarbonate obtained by the above method cannot be used in a field where quality is required.

[0003] Recently, attempts have been made to produce high-quality polycarbonate by the transesterification method. Among these, various proposals regarding a production apparatus have been made, but at present it is still insufficient. is there.

In particular, various types of reaction vessels have been proposed in order to prevent the deterioration of the gel and color of the polymer in the late polymerization zone where the production of the aromatic monohydroxy compound is reduced. There is not enough.

For example, Japanese Patent Application Laid-Open No. 2-153923 discloses a combination of a thin film evaporator and a horizontal stirring tank. However, the thin film evaporator cannot take a large hold-up and has a low viscosity. As the polymer rises, the polymer adheres to and stays on the rotating shaft, thereby deteriorating the quality of the obtained polymer. In addition, horizontal reactors having a stirring center below the center of the vessel as exemplified are also disclosed in JP-A-2-153924 and JP-A-2-153925. A liquid level is generated in the tank, and the gas phase and the liquid phase are clearly separated inside the reaction tank, and the organic substances attached to the gas phase cannot be scraped off, so that the quality of the polymer becomes poor.

Japanese Patent Application Laid-Open No. 63-23926 discloses that a twin-screw vent-type kneading extruder is used for late-stage polymerization, but it is expensive and insufficient in terms of productivity.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an apparatus for efficiently producing a polycarbonate having a low gel and excellent color tone by a transesterification method, particularly an apparatus suitable for late polymerization. It is in.

[0008]

According to the study of the present inventors, when a polycarbonate is produced by transesterification of an aromatic dihydroxy compound and an aromatic diester carbonate, an aromatic monohydroxy compound formed by a transesterification reaction is produced. It was found that gel and color tone deteriorated in a region where the intrinsic viscosity was 0.1 to 0.3 or more where the amount of the compound decreased.
As a result of investigating the cause in more detail, as the amount of the aromatic monohydroxy compound produced decreases, the polymer tends to adhere to the gas phase of the reaction tank, which grows / degrades due to long-term stagnation and falls into the polymerization liquid. As a result, it was found that the gel and color tone of the obtained polymer deteriorated.

Therefore, it is necessary to use a reaction tank having no dead space which causes stagnation of the polymer in the late polymerization region where the production of the aromatic monohydroxy compound is reduced. Further, from the viewpoint of economy, it is necessary to use a reaction tank having a large hold-up and a high productivity per unit volume.

That is, the present invention relates to a horizontal reactor used for continuously producing an aromatic polycarbonate by transesterifying an aromatic dihydroxy compound and an aromatic carbonic acid diester, comprising an end disk and an end disk. A plurality of hollow disks arranged between the partial disks are connected and fixed at predetermined intervals by stirring blades inclined or curved in a direction opposite to the rotation direction, and
The present invention relates to a horizontal single-shaft reactor for producing aromatic polycarbonate, which has a stirring blade having a structure in which a center portion of an end disc is supported by a rotation shaft and has no rotation shaft inside the stirring blade. .

The horizontal single-shaft reactor of the present invention preferably has a heating jacket divided into a plurality of sections. By doing so, it becomes possible to operate the inlet side at a temperature lower by 10 to 100 ° C. than the outlet side.

The aromatic dihydroxy compound and the aromatic carbonic acid diester are reacted in at least one vertical stirring tank,
A prepolymer having an intrinsic viscosity of 0.1 to 0.3 was prepared. The prepolymer was supplied to a horizontal single-shaft reaction tank, and the intrinsic viscosity was 0.1 to 0.3.
It is preferable that the aromatic polycarbonate having a degree of polymerization of 3 to 0.45 is supplied to a horizontal biaxial reaction tank to obtain an aromatic polycarbonate having a higher polymerization degree.

(Stirring blade) The horizontal single-shaft reactor of the present invention comprises:
Plural hollow discs 1 arranged between end discs 9 and 9 '
1 is a stirring blade 13 inclined or curved in a direction opposite to the rotation direction.
By connecting and fixing at predetermined intervals, the end disc 9
The stirring blade has a structure in which the center of 9 'is supported by the rotation shaft and the rotation shaft does not exist inside the stirring blade.

In the stirring blade, the tip of the stirring blade 13 is parallel to and close to the container body wall 1, the liquid is pumped up by the stirring and rotation by the space formed by the tip part and the container body wall 1, and then free by gravity. The liquid is applied onto the gas phase portion of the container body wall 1 by falling while forming a liquid film, and by the stirring blade 13.
It is preferable to have a structure for updating.

By using the stirring blade having such a structure,
Even if the hold-up is increased, the liquid is pumped up along with the stirring rotation by the space formed by the tip of the stirring blade 13 and the container body wall 1, and then falls while forming a free liquid film due to gravity. As a result, the surface area of the reaction solution is kept large because the solution is applied to the gas phase portion of the container body wall,
As a result, a high reaction rate and high productivity are maintained. Further, as the tip of the stirring blade 13 rotates, the liquid film on the container body wall 1 is constantly scraped off and renewed, so that it is possible to obtain a polymer of good quality without generating a gel or a substance causing a decrease in hue. it can. Furthermore, since the rotating shafts 8 and 8 'do not exist inside the stirring blade, a stagnant portion around the shaft does not occur and the quality of the polymer is improved.

(End Disk 9) The end disk 9 preferably has a large number of openings for the purpose of preventing the liquid from remaining in the end plate portion (side wall portion) of the reactor. As such a shape, for example, a disk having a number of cutouts and a hollow disk having a plurality of support plates extending from the center are used. Of these, a notched disk having an opening 10 is preferable.

(Agitating Blade 13) The agitating blade 13 preferably has a tail 14 extending at a tip thereof in a direction opposite to the rotation direction and maintaining a small gap with the container body wall 1. The tail 14
Has the effect of applying the liquid film to the container body wall and improving the pumpability of the reaction solution.

Hereinafter, an example of the horizontal single-shaft reactor according to the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a specific example of the horizontal single-shaft reaction tank of the present invention. FIG. 2 and FIG.
It is an A-B and B-B arrow view. FIG. 4 shows the stirring blade 13.
The following shows a specific example. FIG. 5 is a front view of the blades 7, 7 '. FIG. 6 is a front view of the end disk 9. FIG. 7 is a front view of the hollow disk 11.

In the figure, 1 is a cylindrical container body wall, 2 is a heating device surrounding the container body wall, 3 and 4 are liquid inlets and outlets, and 5 and 6 are side walls (or end plates) on both sides. Reference numeral 7 denotes a plurality of blades whose inner ends are fixed to a rotation shaft 8 at a position close to the side plate 5 on the entrance 3 side, and which is curved in a direction opposite to the rotation direction R (hereinafter, viewed from the center or the axis). The blade surface F in the direction of the rotation axis is inclined so as to scrape and apply the liquid to the side wall 5. A similar blade 7 'is provided at the other end.

Numerals 9, 9 'are notched disks which are supported by the rotating shafts 8, 8' and are provided inside the blades 7, 7 '. A number of notched openings 10, 10' are provided in the outer peripheral portion. Entrance 3
The liquid distribution from the outlet or to the outlet 4 can be appropriately performed.

Reference numeral 11 denotes a hollow disk arranged and supported at predetermined intervals between the notched disks 9 and 9 'via a stirring blade 13, and 12 denotes an opening of the hollow disk 11.

The stirring blades 13 are fixed to the outer periphery of the hollow disk 11 at regular intervals and are formed of a plate-like body that connects the hollow disks 11 to each other. As shown in FIGS. It is inclined in the direction and its tip is close to the main body wall 1, and has a function of scraping up the liquid in the space S formed by the stirring blade 13 and the main body wall 1 and applying the liquid to the main body wall 1.

Further, at the tips of the stirring blades 13, there are provided tails 14 which extend in the direction opposite to the rotation direction R in the vicinity of the body wall 1 in order to effectively carry out the coating distribution operation. It is preferable that the tail 14 does not protrude as much as possible from the surface on the rotation direction R side of the stirring blade 13. FIGS. 4A, 4B and 4C show examples of such a tail 14.

Further, the tail fin 14 may be provided in the entire chamber formed by the hollow disk 11 along the axial direction as in this embodiment, or may be provided in a part depending on the degree of the polymerization reaction.

The hollow disk 11, the stirring blade 13, the tail 1
4 and the body wall 1 are preferably 10 mm or less, and more preferably 5 to 8 mm, the gap between the entrance-side blade 7 and the side wall 5 is 3 mm or less, and the exit-side blade 7 ′ and the side wall. The gap with 5 ′ is preferably 10 mm or less. Further, the blades 7, 7 'may be combined with the cutout discs 9, 9' to be integrated.

When the continuous polymerization of polycarbonate is carried out using the apparatus having the above-described structure, the liquid is continuously injected from the inlet 3 and the hollow disk 11, the stirring blade 13 and the like are gradually rotated by a motor, preferably at 1 to 15 rpm. It is rotated to the number of rotations. The supplied reaction liquid is applied and renewed inside the side wall 5 of the entrance by the stirring blade 7 while the stirring blade 1
3 or the gasket wall 1
Apply and update. Further, the liquid material falls while forming a film shape by these, flows into the next chamber through the opening 12 of the hollow disk 11, and is sequentially sent to the liquid outlet 4 by repeating the same operation.

When the continuous polymerization of the polycarbonate is carried out according to the present invention in this way, not only the reaction is carried out in a very short time, but also the wall of the gas phase portion not immersed in the reaction solution is coated and renewed with the reaction solution. Therefore, there is an advantage that a high-quality polymer can be obtained for a long period of time without generating thermal degradation products on the wall surface.

In the present invention, when the horizontal uniaxial reaction vessel is used with a wide degree of polymerization, it is preferable to divide the heating jacket into a plurality of sections and to operate the inlet side at a lower temperature than the outlet side. The temperature difference in such a case is 10 to 100 ° C, preferably 10 to 50 ° C.

The aromatic dihydroxy compound used in the present invention is not particularly limited. For example, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2 2-bis (4
-Hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxy-t-butylphenyl) propane and the like Bis (hydroxyaryl) alkanes, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1
Bis (hydroxyaryl) cycloalkanes such as bis (hydroxyphenyl) cyclohexane, 4,4 ′
Dihydroxy aryl ethers such as dihydroxy diphenyl ether, dihydroxy aryl sulfides such as 4,4'-dihydroxy diphenyl sulfide, dihydroxy aryl sulfoxides such as 4,4'-dihydroxy diphenyl sulfoxide, 4,4'-
Dihydroxyaryl sulfones such as dihydroxydiphenyl sulfone are used. Particularly, 2,2-bis (4-hydroxyphenyl) propane is preferable.

Examples of the aromatic carbonate diester used in the present invention include esters such as an aryl group and an aralkyl group having 6 to 10 carbon atoms which may be substituted. Specifically, diphenyl carbonate, ditolyl carbonate,
Bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate and the like can be mentioned.

In producing the polycarbonate in the present invention, the above-mentioned aromatic diester carbonate is used in an amount of 1.00 to 1.30 mol, preferably 1.005 to 1.10 mol, per 1 mol of the aromatic dihydroxy compound. Used in amounts.

In the present invention, a polymerization catalyst may be used to increase the polymerization rate when producing a polycarbonate by the transesterification reaction between the aromatic dihydroxy compound and the aromatic carbonic acid diester as described above.

As the polymerization catalyst, an alkali metal compound,
Examples thereof include alkaline earth metal compounds and nitrogen-containing basic compounds.

Examples of the alkali metal compound include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, and lithium acetate. , Sodium stearate, potassium stearate, lithium stearate, sodium salt, potassium salt, lithium salt of bisphenol A, sodium benzoate, potassium benzoate, lithium benzoate and the like.

Examples of the alkaline earth metal compound include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, and carbonate. Examples include magnesium, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate and the like.

Examples of the nitrogen-containing basic compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylamine, triethylamine, dimethylbenzylamine, triphenylamine and the like.

Other polymerization catalysts include alkali metal and alkaline earth metal salts of hydroxides of boron and aluminum, quaternary ammonium salts, alkoxides of alkali metals and alkaline earth metals, alkali metals and alkaline earth metals. Metal organic acid salts, zinc compounds, boron compounds,
Catalysts usually used for esterification and transesterification such as silicon compounds, germanium compounds, organotin compounds, lead compounds, osnium compounds, antimony compounds, and zirconium compounds can be used. However, the present invention is not limited to this. When a catalyst is used, only one type may be used, or two or more types may be used in combination.

These catalysts are used in an amount of 0.000001 to 1% by weight, preferably 0.00001 to 0.5% by weight, more preferably 0.00001 to 0.1% by weight, based on the aromatic dihydroxy compound as the raw material. Is selected in the range.

In the transesterification reaction between the aromatic dihydroxy compound and the aromatic carbonic acid diester of the present invention, the aromatic monohydroxy compound produced by stirring under heating in an inert gas atmosphere is distilled off as is conventionally known. It is done by letting it go out. 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 1 to 0.1 Torr.
The reaction is completed by facilitating the distillation of the aromatic monohydroxy compound produced.

[0041]

According to the present invention, when a polycarbonate resin is produced, by using a specific reactor, a polycarbonate having a small amount of gel and a good hue can be produced by a transesterification reaction.

[0042]

The present invention will be described below in detail with reference to examples. The percentages and parts in the examples are by weight unless otherwise specified.
Or parts by weight. In the following examples, physical properties and the like of polycarbonate were measured as follows.

Intrinsic viscosity: A 0.7 g / dl methylene chloride solution was measured using an Ubbelohde viscometer.

Pellet color: Measured with a color difference meter manufactured by Nippon Denshoku Industries.

[Example 1] Diphenyl carbonate was charged into a melting tank equipped with a stirrer at a ratio of 1.01 mol to 1 mol of 2,2-bis (4-hydroxyphenyl) propane. Dissolve and add the molten mixture to 1
It was transferred to a raw material storage tank maintained at 50 ° C.

Next, a rectification column was provided, and the internal temperature was set to 180 ° C.
While continuously supplying the molten mixture at a rate of 60 kg / hour to a vertical stirrer whose internal pressure is maintained at 30 Torr,
Bisphenol A disodium salt (equivalent to 0.000012 parts by weight) was continuously supplied in an amount of 0.00002 equivalent to 1 mol of 2,2-bis (4-hydroxyphenyl) propane as a polymerization catalyst, and the resulting phenol was subjected to a rectification column. The reaction was performed with more removal.

The obtained reaction product was continuously supplied to a vertical stirrer equipped with another rectification column maintaining the internal temperature at 250 ° C. and the internal pressure at 10 Torr to further react while distilling phenol. And the obtained reaction product was continuously extracted using a gear pump. As a result, a prepolymer having an intrinsic viscosity of 0.20 was obtained.

Next, the prepolymer was heated at an internal temperature of 270 ° C.
The internal pressure is maintained at 1 Torr, and continuously supplied to the horizontal single-screw reaction tank according to the present invention, and the generated phenol is removed from the system and further polymerized to continuously obtain a polycarbonate having an intrinsic viscosity of 0.40. Was. The average residence time during this time was 0.5 hours, and the pellet color of the obtained polycarbonate was L = 64.3, b = -0.1 and 0.5
100μ insoluble in methylene chloride present in Kg
The following microgels (referred to as microgels) were as good as 4 pieces.

Example 2 2-bis (4
-Hydroxyphenyl) propane per mole of 0.00
0002 equivalents of bisphenol A disodium salt (0.
0000012 parts by weight) and 0.0001 equivalent of tetramethylammonium hydride (0.00004
The same operation as in Example 1 was carried out except for using
A polycarbonate having [η] = 0.39 was obtained. The average residence time during this period was 1 hour, the pellet color of the obtained polycarbonate was L = 63.8, b = 0.2, and there was one microgel.

Comparative Example The same operation as in Example 1 was carried out except that the horizontal uniaxial reaction tank having a gas phase portion was used in place of the horizontal uniaxial reaction tank of Example 1, and the intrinsic viscosity was 0.39. Was obtained. The average residence time during this period was 1 hour, and the pellet color of the obtained polycarbonate was L =
62.3, b = 1.2 and 20 microgels were inferior in quality.

[Brief description of the drawings]

FIG. 1 shows a cross-sectional view of a horizontal single-shaft reaction tank used in the present invention.

FIG. 2 is a view of the horizontal uniaxial reaction tank of FIG.

FIG. 3 is a view of the horizontal single-shaft reaction tank of FIG.

FIG. 4 shows a specific example of a stirring blade 13;

FIG. 5 shows a front view of the blades 7 and 7 ′.

6 shows a front view of the end disk 9. FIG.

FIG. 7 shows a front view of the hollow disk 11;

[Description of Signs] 1: Container body wall 2: Heating device 3: Liquid inlet 4: Liquid outlet 5: Side wall 6: Side wall 7, 7 ': Blade 8, 8': Rotating shaft 9, 9 ': Notched disk 10, 10 ': notch opening 11: hollow disk 12: opening of hollow disk 13: stirring blade 14: tail blade F: blade surface S: space formed by stirring blade 13 and vessel wall 1 R: Direction of rotation

Continued on the front page (72) Inventor Katsushi Sasaki 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi Prefecture Inside the Iwakuni Research Center, Teijin Co., Ltd. (72) Inventor Go Muraoka 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi Prefecture Teijin Research Inc. F-term in the center (reference) 4J029 AA09 AB04 AD01 BB12A BB13 BB13A BD03A BF14A BH02 HC05A KE02 KE07 LA10

Claims (9)

[Claims] 1. A horizontal reactor used for continuously producing an aromatic polycarbonate by transesterifying an aromatic dihydroxy compound and an aromatic carbonic diester, comprising: an end disk; and an end disk. A structure in which a plurality of hollow disks disposed therebetween are connected and fixed at predetermined intervals by stirring blades inclined or curved in the direction opposite to the rotation direction, and the center of the end disks is supported by a rotating shaft. A horizontal single-shaft reactor for producing an aromatic polycarbonate, having a stirring blade and having a structure in which a rotating shaft does not exist inside the stirring blade. 2. A horizontal single-screw reactor, wherein a tip of a stirring blade is parallel to and close to a container body wall, and a liquid is pumped with stirring rotation by a space formed by the tip part and the container body wall,
Next, it falls while forming a free liquid film by gravity, and
The production apparatus according to claim 1, wherein the production apparatus is a horizontal reaction vessel having a stirring blade for applying and renewing a liquid to a gas phase portion of a container body wall by a stirring blade. 3. The manufacturing apparatus according to claim 1, wherein the end disk is a notched disk having an opening. 4. The stirring blade according to any one of claims 1 to 3, wherein the stirring blade has a tail extending at a tip thereof in a direction opposite to the rotation direction and holding a small gap with the container body wall. Manufacturing apparatus according to the above. 5. A plurality of blades each having an inner end fixed to a rotating shaft at a position close to the inlet side wall and at a position close to the outlet side wall, and viewed from the axial center with respect to the rotational direction. The manufacturing apparatus according to any one of claims 1 to 4, wherein the plurality of blades that are curved in the opposite direction and extend from the rotation shaft toward the outer peripheral portion of the disk are provided. 6. A blade surface of a plurality of blades, the inner ends of which are fixed to a rotation shaft, and which extend in a direction curved in a direction opposite to the rotation direction,
The manufacturing apparatus according to claim 5, wherein the side wall is inclined so as to apply the liquid by scraping the side wall. 7. The manufacturing apparatus according to claim 6, wherein the blade and the end disk are combined and integrated. 8. The horizontal uniaxial reaction vessel has a plurality of divided heating jackets, and the inlet side jacket is maintained at a temperature lower by 10 to 100 ° C. than the outlet side jacket. The manufacturing apparatus according to claim 1. 9. A liquid supplied to a horizontal single-screw reactor is prepared by reacting an aromatic dihydroxy compound and an aromatic carbonic acid diester in at least one vertical stirring tank, and having an intrinsic viscosity of 0.1 to 0.1. 9. The prepolymer of claim 3, wherein the liquid withdrawn from the horizontal uniaxial reactor is a polycarbonate having an intrinsic viscosity of 0.3 to 0.45.
The manufacturing apparatus according to any one of the above.