JP2002220456A - Method for producing polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polycarbonate excellent in thermal stability substantially free from a residual solvent. SOLUTION: In a method for producing a polycarbonate by solid-phase polymerization using a polycarbonate prepolymer, the method for producing the polycarbonate is specified by that after the polycarbonate prepolymer is crystallized by contacting it with liquid, subcritical or supercritical state carbon dioxide. The polycarbonate is produced by solid-phase polymerization of the prepolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing polycarbonate. More specifically, the present invention relates to a method for producing a polycarbonate having excellent heat stability.

[0002]

2. Description of the Related Art Polycarbonate is used as an engineering plastic in a wide range of industrial fields. The polycarbonate production method includes an interfacial polymerization method in which an aromatic dihydroxy compound such as 2,2-bis (4-hydroxyphenyl) propane is directly reacted with phosgene, and 2,2-bis (4-hydroxyphenyl). ) A melt polymerization method in which an aromatic dihydroxy compound such as propane and a diester carbonate such as diphenyl carbonate are transesterified in a molten state, and an amorphous polycarbonate prepolymer prepared by the melt polymerization method is solidified after crystallization. There is known a solid phase polymerization method in which a polycarbonate is obtained by increasing the molecular weight by phase polymerization.

[0003] In the interfacial polymerization method, toxic phosgene is used in the production process, so there is a problem in safety. In addition, there is a problem in corrosion of production equipment due to methylene chloride, sodium chloride, etc. However, there is a problem that methylene chloride remains and causes deterioration in physical properties. On the other hand, in the melt polymerization method, there is no problem as in the interfacial polymerization method, but in the manufacturing process, in order to distill off the hydroxy compound and the carbonic acid diester in the high-viscosity polycarbonate melt, at a high temperature and under a high vacuum. Requires a long reaction time. Therefore, a special device that can withstand a long-time reaction under high temperature and high vacuum and a particularly powerful stirring device are required as the production device because the product is highly viscous. In addition, the obtained product polycarbonate is not sufficiently stable in quality because it contains a branched structure or a crosslinked structure due to a side reaction accompanying the reaction at a high temperature, and is liable to be colored by a long stay at a high temperature. There's a problem. Furthermore, the polycarbonate obtained by this melt polymerization method has a large content of low molecular weight components such as residual monomers and acetone-soluble components, so that the impact strength is reduced and the mold surface has a fogging or the like during molding. There is a problem of easy adhesion.

Although the solid-state polymerization method can solve the problems of the melt polymerization method, there is a problem in the crystallization step of the amorphous prepolymer when preparing a polycarbonate prepolymer in the production process. . That is, since the amorphous prepolymer obtained here has a melting point lower than the polymerization temperature at which solid-state polymerization is possible, even if an attempt is made to carry out polymerization in the amorphous state, fusion occurs and polymerization is impossible. Therefore, when performing polymerization in a solid state, it is necessary to crystallize this amorphous prepolymer in advance. Regarding the method for crystallizing the prepolymer, for example, in Japanese Patent Application Laid-Open No. Hei 3-223330, after a polycarbonate prepolymer is pulverized, the pulverized material is kept in acetone for a predetermined time to form a porous solid phase polymerization flake. A method for producing polycarbonate by solid-phase polymerization using the flakes has been proposed, but in this case, a solvent recovery system is required, which complicates the production apparatus and leaves residual solvent. There is a problem of doing. In JP-A-9-235368, a poor solvent such as n-heptane is added to a solution of a polycarbonate prepolymer in methylene chloride to precipitate the prepolymer, and then the solvent is removed. A phase polymerization method has been proposed, but also in this case, there is a problem that the production system becomes complicated because a solvent recovery system is required, and the solvent remains.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a polycarbonate which is substantially free from residual solvents and has excellent heat stability.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that in a method for producing polycarbonate by solid-state polymerization of a polycarbonate prepolymer, the polycarbonate prepolymer is converted into a liquid or a sub-polymer. It has been found that the above-mentioned object can be achieved by solid-phase polymerization after contact with carbon dioxide in a critical or supercritical state for crystallization, and the present invention has been completed based on these findings.

That is, the gist of the present invention is as follows. (1) In a method of producing a polycarbonate by increasing the molecular weight of a polycarbonate prepolymer in a solid state,
A method for producing a polycarbonate, comprising subjecting a polycarbonate prepolymer to crystallization by bringing it into contact with liquid, subcritical or supercritical carbon dioxide, followed by solid phase polymerization. (2) The method for producing a polycarbonate according to the above (1), wherein the viscosity average molecular weight of the polycarbonate prepolymer is 2,000 to 20,000. (3) The method for producing a polycarbonate according to the above (1) or (2), wherein the solid phase polymerization is carried out in the presence of a quaternary phosphonium salt catalyst. (4) The method for producing a polycarbonate according to any one of the above (1) to (3), wherein the polycarbonate prepolymer is obtained by a transesterification method between a dihydroxy compound and a carbonic acid diester. (5) The method according to any one of (1) to (4) above, wherein the polycarbonate prepolymer is crystallized by contacting it with carbon dioxide in a liquid, subcritical or supercritical state, and then the carbon dioxide is separated under reduced pressure. Production method of polycarbonate. (6) The above-mentioned (1) to which the carbon dioxide used for crystallization of the polycarbonate prepolymer is recovered and recycled.
(5) The method for producing a polycarbonate according to any of (5).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method for producing a polycarbonate by increasing the molecular weight of a polycarbonate prepolymer in a solid state, by contacting the polycarbonate prepolymer with carbon dioxide in a liquid, subcritical or supercritical state. This is a method for producing a polycarbonate, which comprises subjecting to crystallization followed by solid phase polymerization. Therefore, the method for producing a polycarbonate of the present invention comprises: [1] a step of preparing a polycarbonate prepolymer;
This is a method for producing polycarbonate, comprising a step of crystallizing the prepolymer and a step [3] of increasing the molecular weight by solid phase polymerization.

[0009] The process for preparing the polycarbonate prepolymer is not particularly limited in the polymerization method, and may be a conventional method using an interfacial polymerization reaction, a method using an oxidative carbonylation reaction between a dihydroxy compound and carbon monoxide, a method using a dihydroxy compound. A method capable of producing a polycarbonate prepolymer, such as a method based on the reaction of carbon dioxide with carbon dioxide or a melt polymerization method based on a transesterification reaction may be employed. Here, in the case of producing a polycarbonate prepolymer by an interfacial polymerization method, a non-halogen solvent such as an ether solvent such as tetrahydrofuran or a hydrocarbon solvent such as paraxylene or toluene is used in consideration of the effect on the environment. Alternatively, it is desirable to carry out the interfacial polymerization reaction using a ketone solvent such as methyl ethyl ketone. On the other hand, when a polycarbonate prepolymer is produced by a method of reacting a dihydroxy compound with carbon monoxide or carbon dioxide, it is carried out without a solvent, or with the same care as in the selection of a solvent in the above interfacial polymerization method,
It is desirable to employ a separable method such as using a solid catalyst so that the catalyst component used in the reaction is not mixed into the prepolymer. Furthermore, in the case of the melt polymerization method by transesterification, there is no effect on the environment because no solvent is used, and this is a method suitable for application to the preparation of this polycarbonate prepolymer. When preparing a polycarbonate prepolymer by this melt polymerization method,
As a raw material, a prepolymer is prepared using (a) a dihydroxy compound and (b) a carbonic acid diester, and if necessary, using (c) a terminal terminator, (d) a branching agent, and (e) an antioxidant. And when preparing this prepolymer,
As the polymerization catalyst, (f) a nitrogen-containing organic basic compound is suitably used. Hereinafter, these raw materials and additives will be described in detail.

(A) Dihydroxy compound As the dihydroxy compound used as a raw material in the present invention, there are an aromatic dihydroxy compound and an aliphatic dihydroxy compound. Among them, an aromatic dihydroxy compound is preferable, and when an aliphatic dihydroxy compound is used. Is preferably used as a mixture with an aromatic dihydroxy compound.

The aromatic dihydroxy compound includes:
General formula (1)

[0012]

Embedded image

[In the formula (1), R ¹ and R ² each independently represent a halogen atom, an alkyl group having 1 to 8 carbon atoms or a phenyl group, and m and n each represent an integer of 0 to 4. .
Z is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, -S-, _{-SO -, - SO 2 -,} - O -, - CO-
Or the following equation (2) or the following equation (3)

[0014]

Embedded image

And a group represented by the formula: ] Are preferably used. Here, in the general formula (1),
The halogen atom represented by R ¹ and R ² may be any of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and the alkyl group having 1 to 8 carbon atoms may be a methyl group, an ethyl group, a -Propyl group, isopropyl group, n
-Butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, cyclohexyl group,
Examples include a heptyl group and an octyl group. The alkylene group having 1 to 8 carbon atoms and the alkylidene group having 2 to 8 carbon atoms represented by Z in the formula include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group,
Examples include a hexylene group, an ethylidene group, and an isopropylidene group. Examples of the cycloalkylene group having 5 to 15 carbon atoms and the cycloalkylidene group having 5 to 15 carbon atoms include a cyclopentylene group, a cyclohexylene group, a cyclopentylidene group, and a cyclohexylidene group.

As the aromatic dihydroxy compound represented by the general formula (1), for example, bis (4-hydroxyphenyl) methane, bis (3-methyl-4-hydroxyphenyl) methane, bis (3-hydroxyphenyl) methane, Chloro-4-hydroxyphenyl) methane, bis (3,5-dibromo-
4-hydroxyphenyl) methane, 1,1-bis (4-
Hydroxyphenyl) phenylmethane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (2
-T-butyl-4-hydroxy-3-methylphenyl)
Ethane, 1,1-bis (2-t-butyl-4-hydroxy-3-methylphenyl) ethane, 1-phenyl-1,
1-bis (3-fluoro-4-hydroxy-3-methylphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (2-methyl-4-hydroxyphenyl) propane, 2,2-bis (3-t-butyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxy) Phenyl) propane, 1,1-bis (2-t-butyl-
4-hydroxy-5-methylphenyl) propane, 2,
2-bis (3-chloro-4-hydroxyphenyl) propane, 2,2-bis (3-fluoro-4-hydroxyphenyl) propane, 2,2-bis (3-bromo-4-hydroxyphenyl) propane, , 2-bis (3,5-
Difluoro-4-hydroxyphenyl) propane, 2,
2-bis (3,5-dichloro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dibromo-4-)
Hydroxyphenyl) propane, 2,2-bis (3-bromo-5-chloro-4-hydroxyphenyl) propane, 2,2-bis (3-phenyl-4-hydroxyphenyl) propane, 2,2-bis (4 -Hydroxyphenyl) butane, 2,2-bis (3-methyl-4-hydroxyphenyl) butane, 1,1-bis (2-butyl-5-
Methyl-4-hydroxyphenyl) butane, 1,1-bis (2-t-butyl-5-methyl-4-hydroxyphenyl) butane, 1,1-bis (2-t-butyl-5-methyl-4- Hydroxyphenyl) isobutane, 1,1-
Bis (2-t-amyl-5-methyl-4-hydroxyphenyl) butane, 2,2-bis (3,5-dichloro-4)
-Hydroxyphenyl) butane, 2,2-bis (3,5
-Dibromo-4-hydroxyphenyl) butane, 4,4
-Bis (4-hydroxyphenyl) heptane, 1,1-
Bis (hydroxyaryl) alkanes such as bis (2-t-butyl-5-methyl-4-hydroxyphenyl) heptane and 2,2-bis (4-hydroxyphenyl) octane; 1,1-bis (4-hydroxy Phenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl)
Cyclohexane, 1,1-bis (3-methyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (3-
Bis (cyclohexyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (3-phenyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,5,5-trimethylcyclohexane (Hydroxyaryl) cycloalkanes;
Bis (4-hydroxyphenyl) ether, bis (3-
Bis (hydroxyaryl) ethers such as methyl-4-hydroxyphenyl) ether; bis (4-hydroxyphenyl) ketones such as 4,4'-dihydroxybenzophenone; bis (4-hydroxyphenyl) sulfide, bis (3- Methyl-4-hydroxyphenyl)
Bis (hydroxyaryl) sulfides such as sulfide; bis (4-hydroxyphenyl) sulfoxide,
Bis (3-methyl-4-hydroxyphenyl) sulfoxide, bis (3-phenyl-4-hydroxyphenyl)
Bis (hydroxyaryl) sulfoxides such as sulfoxide; bis (4hydroxyphenyl) sulfone, bis (3-methyl-4-hydroxyphenyl) sulfone,
Bis (hydroxyaryl) sulfones such as bis (3-phenyl-4-hydroxyphenyl) sulfone;
4'-dihydroxybiphenyl, 2,2'-dimethyl-
4,4'-dihydroxybiphenyl, 3,3'-dimethyl-4,4'-dihydroxybiphenyl, 3,3'-dicyclohexyl-4,4'-dihydroxybiphenyl,
Dihydroxybiphenyls such as 3,3′-difluoro-4,4′-dihydroxybiphenyl; 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene, etc. Bis (4-hydroxyphenyl) fluorenes;
1,4-bis [2- (4-hydroxyphenyl) -2-
Bis [2- (4-hydroxyphenyl) -2-propyl] benzenes such as propyl] benzene and 1,3-bis [2- (4-hydroxyphenyl) -2-propyl] benzene. Among these aromatic dihydroxy compounds represented by the general formula (1), 2,2-bis (4-hydroxyphenyl) propane [hereinafter may be abbreviated as bisphenol A. Is a particularly preferred compound.

The aromatic dihydroxy compound other than the compound represented by the general formula (1) includes, for example, resorcin, 3-methylresorcin, 3-ethylresorcin, 3-propylresorcin, 3-butylresorcin,
3-t-butyl resorcinol, 3-phenyl resorcinol,
3-cumylresorcin, 2,3,4,6-tetrafluororesorcin, 2,3,4,6-tetrabromoresorcin, catechol, hydroquinone, 3-methylhydroquinone, 3-ethylhydroquinone, 3-propylhydroquinone, -Butylhydroquinone, 3-t-butylhydroquinone, 3-phenylhydroquinone, 3-
Cumyl hydroquinone, 2,5-dichlorohydroquinone, 2,3,5,6-tetramethylhydroquinone,
2,3,4,6-tetra-t-butylhydroquinone,
Examples include compounds such as 2,3,5,6-tetrafluorohydroquinone and 2,3,5,6-tetrabromohydroquinone.

Further, ethoxylates or propoxylates of dihydric alcohols and phenols, for example, bis-oxyethyl bisphenol A, bis-oxyethyl-tetrachlorobisphenol A, bis-oxyethyl-tetrachlorohydroquinone and the like can be mentioned. In addition, diesters of dihydroxy compounds such as bisphenol A diacetate, bisphenol A dipropionate, bisphenol A dibutylate, bisphenol A dibenzoate, and bisphenol A bismethyl carbonate, bisphenol A Dicarbonates of dihydroxy compounds such as bisethyl carbonate of bisphenol A and bisphenyl carbonate of bisphenol A, bisphenol A monomethyl carbonate, bisphenol A monoethyl carbonate, bisphenol A monopropyl carbonate, bisphenol A monophenyl carbonate, etc. Monocarbonates of dihydroxy compounds can be mentioned.

As the aliphatic dihydroxy compound, for example, butane-1,4-diol, 2,2-dimethylpropane-1,3-diol, hexane-1,6-diol
Diol, diethylene glycol, triethylene glycol, tetraethylene glycol, octaethylene glycol, dipropylene glycol, N, N-methyldiethanolamine, cyclohexane-1,3-diol,
Cyclohexane-1,4-diol, 1,4-dimethylolcyclohexane, p-xylylene glycol, 2,
2-bis- (4-hydroxycyclohexyl) -propane and the like. Further, similarly to these dihydroxy compounds, compounds having a carboxyl group such as adipic acid, isophthalic acid, and terephthalic acid can also be used.

(B) Carbonic Diester Next, as the carbonic diester, for example, at least one compound selected from diaryl carbonate compounds, dialkyl carbonate compounds and alkylaryl carbonate compounds can be used.

The diaryl carbonate compound represented by the general formula (4)

[0022]

Embedded image [In the formula (4), Ar ¹ and Ar ² each independently represent an aryl group, which may be the same or different. Or a compound represented by the general formula (5)

[0023]

Embedded image [In the formula (5), Ar ³ and Ar ⁴ each independently represent an aryl group, which may be the same or different, and D ¹ is a residue obtained by removing two hydroxyl groups from the aromatic dihydroxy compound. Represents a group. ] It is a compound represented by these.

The dialkyl carbonate compound is represented by the general formula (6)

[0025]

Embedded image [In the formula (6), R ³ and R ⁴ each independently represent a carbon number of 1 to 6;
And a cycloalkyl group having 4 to 7 carbon atoms, which may be the same or different from each other. ]
Or a compound represented by the general formula (7)

[0026]

Embedded image [In the formula (7), R ⁵ and R ⁶ each independently represent a carbon number of 1 to 6;
And a cycloalkyl group having 4 to 7 carbon atoms, which may be the same or different from each other,
² represents a residue obtained by removing two hydroxyl groups from the aromatic dihydroxy compound. ] It is a compound represented by these.

The alkylaryl carbonate compound represented by the general formula (8)

[0028]

Embedded image Wherein (8), Ar ⁵ is an aryl group, R ⁷ is C 1 -C
An alkyl group of 6 to 6 or a cycloalkyl group of 4 to 7 carbon atoms. Or a compound represented by the general formula (9)

[0029]

Embedded image [In the formula (9), Ar ⁶ is an aryl group, and R ⁸ is a group having 1 carbon atom.
It indicates 6 alkyl group or cycloalkyl group having a carbon number of 4 to 7, D ³ represents a residue obtained by removing two hydroxyl groups from the above aromatic dihydroxy compound. ] It is a compound represented by these.

In these general formulas (4) to (9), Ar
Examples of the aryl group represented by ^{1 to} Ar ⁶ include a phenyl group,
Examples thereof include a tolyl group, a xylyl group, a naphthyl group and a cresyl group. Examples of the alkyl group having 1 to 6 carbon atoms or the cycloalkyl group having 4 to 7 carbon atoms represented by R ^{3 to} R ⁸ include a methyl group and an ethyl group. Groups, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, cyclohexyl group and the like.

Examples of the diaryl carbonate compound include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, and bisphenol A bisphenylcarbonate. No. Examples of the dialkyl carbonate compound include diethyl carbonate, dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, and bisphenol A bismethyl carbonate.

Further, as the alkylaryl carbonate compound, for example, methylphenyl carbonate, ethylphenyl carbonate, butylphenyl carbonate, cyclohexylphenyl carbonate, bisphenol A
Methyl phenyl carbonate and the like can be mentioned. These carbonic acid diesters include 1 selected from the above compounds.
Species or two or more compounds can be used, and among them, it is particularly preferable to use diphenyl carbonate.

(C) Terminal terminator Next, examples of the terminal terminator include on-butylphenol, mn-butylphenol, pn-butylphenol, o-isobutylphenol, m-isobutylphenol and p-butylphenol. Isobutylphenol, ot-
Butylphenol, mt-butylphenol, pt
-Butylphenol, on-pentylphenol, m
-N-pentylphenol, pn-pentylphenol, on-hexylphenol, mn-hexylphenol, pn-hexylphenol, o-cyclohexylphenol, m-cyclohexylphenol, p
-Cyclohexylphenol, o-phenylphenol, m-phenylphenol, p-phenylphenol, on-nonylphenol, mn-nonylphenol, pn-nonylphenol, o-cumylphenol, m-cumylphenol, p -Cumylphenol, o
-Naphthylphenol, m-naphthylphenol, p-
Naphthylphenol, 2,6-di-t-butylphenol, 2,5-di-t-butylphenol, 2,4-di-
t-butylphenol, 3,5-di-t-butylphenol, 2,5-dicumylphenol, 3,5-dicumylphenol, p-tert-butylphenol, p-cumylphenol, p-phenylphenol, o, m , Pt
-Octylphenol, o, m, pn-octylphenol, o, m, pt-dodecylphenol, o,
Monohydric phenols such as m, pn-dodecylphenol are exemplified. These compounds may be used alone or in combination of two or more.

Also, among these compounds, 2,6-di-t-butylphenol, 2,5-di-t-butylphenol, 2,4-di-t-butylphenol, 3,5-
Di-t-butylphenol, 2,5-dicumylphenol, 3,5-dicumylphenol, pt-butylphenol, p-cumylphenol, pt-octylphenol, p-phenylphenol, pt-dodecyl Phenol is particularly preferred.

(D) Branching Agent Next, as the branching agent, a polyfunctional organic compound having three or more functional groups is used. For example, a compound having three or more functional groups such as a hydroxyl group, a carboxyl group, an amino group, an imino group, a formyl group, an acid halide group, and a haloformate group in one compound is preferably used.

Examples of such branching agents include phloroglucin, melitic acid, trimellitic acid, trimellitic chloride, trimellitic anhydride, gallic acid, n-propyl gallate, protocatechuic acid, pyromellitic acid, and pyromellitic acid. Acid second anhydride, α-resorcinic acid, β-resorcinic acid, resorcinaldehyde, trimellityl chloride, trimethyltrichloride, 4-chloroformylphthalic anhydride, benzophenonetetracarboxylic acid, 2,
4,4′-trihydroxybenzophenone, 2,2 ′,
4,4′-tetrahydroxybenzophenone, 2,4
4'-trihydroxyphenyl ether, 2,2 ',
4,4′-tetrahydroxyphenyl ether, 2,
4,4′-trihydroxydiphenyl-2-propane,
2,2′-bis (2,4-dihydroxy) propane,
2,2 ′, 4,4′-tetrahydroxydiphenylmethane, 2,4,4′-trihydroxydiphenylmethane,
1- [α-methyl-α- (4′-hydroxyphenyl)
Ethyl] -4- [α ′, α′-bis (4 ″ -hydroxyphenyl) ethyl] benzene, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropyl Benzene, 2,6-bis (2′-hydroxy-
5′-methylbenzyl) -4-methylphenol, 4,
6-dimethyl-2,4,6-tris (4′-hydroxyphenyl) -heptene-2,4,6-dimethyl-2,
4,6-dimethyl-tris (4-hydroxyphenyl)
-Heptane-2,1,3,5-tris (4-hydroxyphenyl) -benzene, 1,1,1-tris (4'-hydroxyphenyl) -ethane, 2,2-bis [4,4-
Bis (4'-hydroxyphenyl) cyclohexyl]-
Propane, 2,6-bis (2′-hydroxy-5′-isopropylbenzyl) -4-isopropylphenol,
Bis [2-hydroxy-3- (2'-hydroxy-5 '
-Methylbenzyl) -5-methylphenyl] methane, bis [2-hydroxy-3- (2'-hydroxy-5'-
Isopropylbenzyl) -5-methylphenyl] methane, tetrakis (4-hydroxyphenyl) methane, tris (4-hydroxyphenyl) phenylmethane,
2 ', 4,7-trihydroxyflavan, 2,4,4-
Trimethyl-2 ′, 4′-dihydroxyphenylisopropyl) benzene, tris (4′-hydroxyaryl) -amyl-s-triazine, 1- [α-methyl-α
-(4'-hydroxyphenyl) ethyl] -3-
[Α ′, α′-bis (4 ″ -hydroxyphenyl) ethyl] benzene, isatin bis (o-cresol), α,
α, α ′, α′-tetrakis (4-hydroxyphenyl) -p-xylene, α, α, α ′, α′-tetrakis (3-methyl-4-hydroxyphenyl) -p-xylene, α, α, α ′, α′-tetrakis (2-methyl-4
-Hydroxyphenyl) -p-xylene, α, α,
α ′, α′-tetrakis (2,5-dimethyl-4-hydroxyphenyl) -p-xylene, α, α, α ′, α ′
-Tetrakis (2,6-dimethyl-4-hydroxyphenyl) -p-xylene, α, α′-dimethyl-α, α,
α ', α'-tetrakis (4-hydroxyphenyl)-
p-xylene and the like. These branching agents are:
Species may be used alone or in combination of two or more.

Among these branching agents, 1,1,1-tris (4-hydroxyphenyl) ethane, 1,1,1-tris (4-hydroxy-3-methylphenyl) ethane,
1,1,1-tris (4-hydroxy-3,5-dimethylphenyl) ethane, 1,1,1-tris (3-chloro-4-hydroxyphenyl) ethane, 1,1,1-tris (3 5-dichloro-4-hydroxyphenyl) ethane, 1,1,1-tris (3-bromo-4-hydroxyphenyl) ethane, 1,1,1-tris (3,5-dibromo-4-hydroxyphenyl) ethane , Tris (4-
Hydroxyphenyl) methane, tris (4-hydroxy-3-methylphenyl) methane, tris (4-hydroxyphenyl-3,5-dimethylphenyl) methane, tris (3-chloro-4-hydroxyphenyl) methane, tris (3 , 5-Dichloro-4-hydroxyphenyl) methane, tris (3-bromo-4-hydroxyphenyl)
Methane, tris (3,5-dibromo-4-hydroxyphenyl) methane, α, α′-dimethyl-α, α, α ′,
α′-Tetrakis (4-hydroxyphenyl) -p-xylene and the like are particularly preferred.

(E) Antioxidant Further, as the antioxidant, a phosphorus-based antioxidant is preferable, for example, trialkyl phosphite, tricycloalkyl phosphite, triaryl phosphite,
Monoalkyl diaryl phosphite, trialkyl phosphate, tricycloalkyl phosphate, triaryl phosphate and the like are preferably used.

(F) Nitrogen-Containing Organic Basic Compound Next, as the nitrogen-containing organic basic compound used as a catalyst in the reaction between the dihydroxy compound and the carbonic acid diester, an aliphatic tertiary amine compound or an aromatic tertiary amine compound is used. Examples include amine compounds and nitrogen-containing heterocyclic compounds. Further, the following general formula (10)

[0040]

Embedded image [In the formula (10), R ⁹ represents a hydrocarbon group, and X ¹ represents a halogen atom, a hydroxyl group, an alkyloxy group, an aryloxy group or a monovalent anion-forming group. And a quaternary ammonium salt represented by the formula: Where R
Examples of the hydrocarbon group represented by ⁹ include a methyl group, an ethyl group,
Alkyl groups such as propyl group, butyl group, pentyl group, hexyl group and octyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; aryl groups such as phenyl group, tolyl group, naphthyl group, biphenyl group, and benzyl group Arylalkyl group. These four R ^{9 's} may be the same or different from each other, or two R ^{9' s} may combine to form a ring structure. Examples of the monovalent anion-forming group represented by X ¹ include R′COO—, HCO ₃ —, (R′O)
₂ P (＝ O) O— or —BR ″ ₄ [where R ′ represents an alkyl group or an aryl group, and R ″ represents a hydrogen atom, an alkyl group or an aryl group. ] The group represented by this is mentioned.

Examples of these quaternary ammonium salts include ammonium hydroxide having an alkyl group such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide and trimethylbenzylammonium hydroxide, an aryl group and an araryl group. And basic salts such as tetramethylammonium borohydride, tetrabutylammonium borohydride, tetrabutylammonium tetraphenylborate, and tetramethylammonium tetraphenylborate. Among these nitrogen-containing organic basic compounds, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, tetramethylammonium borohydride, and tetrabutylammonium borohydride are preferable, and tetramethylammonium hydroxide is particularly preferable. This is because these compounds have characteristics of high catalytic activity and easy thermal decomposition, so that they hardly remain in polycarbonate. These nitrogen-containing organic basic compounds may be used alone or in combination of two or more.

[1] Production of Polycarbonate Prepolymer Next, the production method of the polycarbonate prepolymer is as follows.
If necessary, a polycarbonate prepolymer can be prepared while adding an end terminator, a branching agent, an antioxidant, and the like, and treating the mixture under heating to thereby remove the aromatic monohydroxy compound. The prepolymer obtained in the prepolymer production step preferably has a viscosity average molecular weight in the range of 2,000 to 20,000. In this production step, the above-mentioned nitrogen-containing organic basic compound is used as a polymerization catalyst. At the same time as the nitrogen-containing organic basic compound, a phosphorus-containing basic compound of a solid phase polymerization catalyst described later may be added. This phosphorus-containing basic compound is dispersed and remains in the produced polycarbonate prepolymer, and is used as a catalyst in the subsequent solid-phase polymerization.

The production of the polycarbonate prepolymer is preferably carried out without solvent. Examples of the solvent include aromatic compounds such as diphenyl ether, halogenated diphenyl ether, benzophenone, polyphenyl ether, dichlorobenzene and methylnaphthalene. Gases (including supercritical state) such as carbon dioxide, nitrous oxide, and nitrogen; alkanes such as chlorofluorohydrocarbon, ethane, and propane; cyclohexane, tricyclo (5,2,10) decane, cyclooctane, and cyclodecane A solvent inert to the reaction of cycloalkanes or alkenes such as ethylene and propylene may be used.

Next, the ratio of the hydroxy compound and the diester carbonate used as raw materials depends on the type of the compound used, the reaction temperature and the reaction conditions such as the reaction pressure. However, the diester carbonate is based on 1 mol of the dihydroxy compound. And usually 0.9 to 2.5 mol, preferably 0.9
It is used at a ratio of 5 to 2.0 mol, more preferably 0.98 to 1.5 mol. In addition, when a terminal stopping agent that is a monovalent hydroxy compound or a branching agent that is a polyfunctional organic compound having three or more functional groups is used, the terminal stopping agent is based on 1 mol of the dihydroxy compound. Usually 0.001 to 20 mol, preferably 0.0025 to 15
Mol, more preferably 0.005 to 10 mol, and the branching agent is usually 0.001 to 20 mol, preferably 0.002 mol, per 1 mol of the dihydroxy compound.
It is used at a ratio of 5 to 15 mol, more preferably 0.005 to 10 mol.

As for the amount of the catalyst used,
10 moles per mole of the xy compound ^-2-10^-8Mol, yo
More preferably 10^-3-10^-7Preferably using moles
No. The amount of this catalyst used is 10^-8If less than the mole,
Of the catalyst may be insufficient, and 10^-2Mole
Exceeding the limit will result in poor polycarbonate quality and economic inconvenience.
This is not preferable because it may be advantageous.

The reaction temperature, reaction pressure and reaction time vary depending on various conditions such as the kind of the starting compound used, the kind of the catalyst and the amount used thereof, and the molecular weight required for the obtained prepolymer. Is 50 ~
350 ° C., preferably 100 to 320 ° C., more preferably 150 to 280 ° C., and the reaction pressure is 1 Pa to 0.5.
MPa (Gauge), reaction time is 1 minute to 100 hours,
Preferably, it is selected in the range of 2 minutes to 10 hours. In setting these reaction conditions, it is desirable to carry out this reaction at a temperature as low as possible and in a short time so that coloring of the prepolymer can be avoided.

As a reactor used in this prepolymer production step, a conventionally known polymerization reactor can be used. This reaction step may be performed in one step or may be performed by dividing into more steps. When a plurality of reactors are used, the reactors can be connected in series or in parallel. The prepolymer may be manufactured by a batch method, a continuous method, or a method using both of them. Then, in this prepolymer production step, an aromatic monohydroxy compound in a form in which a hydroxyl group is bonded to an aryl group of diaryl carbonate is generated as the reaction proceeds. The reaction rate can be increased by removing the generated aromatic monohydroxy compound out of the reaction system. Therefore, at the same time as stirring the contents of the reactor, an inert gas such as nitrogen gas, argon gas, helium gas or carbon dioxide or a lower hydrocarbon gas is introduced, and the generated aromatic monohydroxy compound is introduced into the introduced gas. It is preferable to remove the water by accompanying it. Further, the aromatic monohydroxy compound may be removed by reducing the pressure in the reactor, and further, the aromatic monohydroxy compound may be removed by reducing the pressure in the reactor and introducing the inert gas. You may. In the polycarbonate prepolymer thus obtained, there are those in which the chemical structures of the molecular chain terminals are phenyl carbonate and those having a hydroxyl group, and these phenyl carbonate terminal: hydroxyl terminal is 1: 1. １ ： 1: 0.1, preferably those having the same ratio of 1: 0.6-1: 0.25.

[2] Crystallization of Polycarbonate Prepolymer Next, the polycarbonate prepolymer thus obtained is brought into contact with carbon dioxide in a liquid, subcritical or supercritical state to crystallize it. The carbon dioxide in a subcritical or supercritical state is separated by vaporization under reduced pressure. As a method of mixing liquid, subcritical or supercritical carbon dioxide with the polycarbonate prepolymer, for example, while the molten polycarbonate prepolymer is flowing through the line mixer, Liquefied carbon dioxide is injected into the upstream pipe, and the polycarbonate prepolymer and liquefied carbon dioxide can be mixed in a line mixer. Further, while stirring the solid state polycarbonate prepolymer in the stirring tank, liquid, subcritical or supercritical carbon dioxide may be injected and mixed therein.

When mixing the polycarbonate prepolymer with carbon dioxide in a liquid or subcritical or supercritical state, if it is carried out in the presence of oxygen, undesired quality problems such as coloring may occur. It is important to sufficiently replace oxygen in the apparatus and the production apparatus with an inert gas. Examples of the inert gas include carbon dioxide gas, nitrogen gas, and argon gas. Among them, using carbon dioxide gas,
It is economical to circulate and use it in the production apparatus together with the carbon dioxide gas recovered after vaporization in the crystallization step.

The mixing ratio of the polycarbonate prepolymer and carbon dioxide in a liquid, subcritical or supercritical state is expressed by the mass ratio of the former: the latter = 1: 0.0
05 to 1: 100, preferably 1: 0.01 to 1:50
It is. The contact time between the polycarbonate prepolymer and liquid, subcritical or supercritical carbon dioxide is 0.5 to 300 minutes, preferably 1 to 180 minutes. The mixture of the polycarbonate prepolymer and the liquid, subcritical or supercritical carbon dioxide which have been mixed in this way is introduced into, for example, a flash drum, and the polycarbonate prepolymer is vaporized by flashing under reduced pressure. Separate from polymer. By mixing the polycarbonate prepolymer and liquid, carbon dioxide in a subcritical or supercritical state in this way,
Crystallinity of polycarbonate prepolymer is 5-50%
Thus, a polycarbonate prepolymer substantially free of a solvent is obtained.

[3] Solid-phase polymerization of crystallized polycarbonate prepolymer Next, the step of solid-phase polymerization of the crystallized polycarbonate prepolymer to increase the molecular weight is performed without using a catalyst or using a polymerization catalyst. The polymerization is carried out using a phosphorus-containing basic compound, preferably a quaternary phosphonium salt. This polymerization catalyst may be added in the step of preparing the polycarbonate prepolymer, or may be added in the crystallization step. This solid-phase polymerization step includes a method in a solid state and a method in a swollen solid state. Either method may be used, but the method in the solid state using an inert gas is a residual method. It is preferable because the amount of the solvent is small and it is easy to obtain a polycarbonate having excellent thermal stability.

The quaternary phosphonium salt used in the solid phase polymerization is not particularly limited, but may be, for example, the following general formula (11) or (12)

[0053]

Embedded image [In the formulas (11) and (12), R ¹⁰ represents an organic group, and four R ^{10 s} may be the same or different from each other, and two R ^10s may combine to form a ring structure. Good. Also,
X ² represents a halogen atom, a hydroxyl group, an alkyloxy group, an aryloxy group or a monovalent anion-forming group;
Y ¹ represents a divalent anion-forming group. ] Can be used.

In the above formulas (11) and (12), the organic group represented by R ¹⁰ is, for example, a methyl group,
Alkyl groups such as ethyl group, propyl group, butyl group, pentyl group, hexyl group and octyl group, cycloalkyl groups such as cyclohexyl group, aryl groups such as phenyl group, tolyl group, naphthyl group, biphenyl group, and benzyl group And arylalkyl groups. Also, X ²
The monovalent anion-forming group represented by R'COO
—, HCO ₃ —, (R′O) ₂ P (＝ O) O— or —
BR ″ ₄ [where R ′ represents an alkyl group or an aryl group, and R ″ represents a hydrogen atom, an alkyl group or an aryl group. And the divalent anion-forming group represented by Y ¹ includes —CO ₃ — and the like.

Such quaternary phosphonium salts include:
For example, tetraphenylphosphonium hydroxide, tetranaphthylphosphonium hydroxide, tetra (chlorophenyl) phosphonium hydroxide, tetra (biphenyl) phosphonium hydroxide, tetratolylphosphonium hydroxide, tetramethylphosphonium hydroxide, tetraethylphosphonium hydroxide, tetrabutylphosphonium Tetra (aryl) phosphonium hydroxides such as hydroxides and tetra (alkyl) phosphonium hydroxides, as well as tetramethylphosphonium tetraphenylborate, tetraphenylphosphonium bromide, tetraphenylphosphonium phenolate, tetraphenylphosphonium tetraphenylborate, methyl Triphenylphosphonium tetraphenylborate Benzyltriphenylphosphonium tetraphenylborate, biphenyltriphenylphosphonium tetraphenylborate, tetratolylphosphonium tetraphenylborate, tetraphenylphosphonium phenolate, tetra (pt-butylphenyl) phosphonium diphenyl phosphate, triphenylbutylphosphonium phenolate, triphenyl Phenylbutylphosphonium tetraphenylborate and the like.

Among these quaternary phosphonium salts, phosphonium salts having an alkyl group, specifically, tetramethylphosphonium methyltriphenylborate, tetraethylphosphoniumethyltriphenylborate, tetrapropylphosphoniumpropyltriphenylborate, tetrabutylphosphoniumbutyl Triphenyl borate, tetrabutyl phosphonium tetraphenyl borate, tetraethyl phosphonium tetraphenyl borate, trimethyl ethyl phosphonium trimethyl phenyl borate, trimethyl benzyl phosphonium benzyl triphenyl borate, etc., have high catalytic activity, are easily thermally decomposed and remain in polycarbonate. It is particularly preferably used because it is difficult.

Further, tetraalkylphosphonium salts such as tetramethylphosphonium hydroxide, tetraethylphosphonium hydroxide and tetrabutylphosphonium hydroxide have relatively low decomposition temperatures, so that they are easily decomposed and contained as impurities in the product polycarbonate. Less likely to remain. In addition, since these compounds have a small number of carbon atoms, it is possible to reduce the basic unit in the production of polycarbonate, which is preferable in terms of cost.

In addition to the compounds represented by the above general formulas (11) and (12), for example, bis-tetraphenylphosphonium salt of 2,2-bis (4-hydroxyphenyl) propane, ethylenebis (triphenyl) Phosphonium) dibromide, trimethylenebis (triphenylphosphonium) -bis (tetraphenylborate), and the like.

Further, quaternary phosphonium salts having an aryl group and / or a branched alkyl group can also be used. For example, general formulas (13) and (14)

[0060]

Embedded image [In the formulas (13) and (14), R ¹¹ represents at least one group selected from an aryl group or a branched alkyl group, and R ¹² represents an alkyl group, an alkyl group having a substituent, an aryl group or a substituted 2 shows an aryl group having a group. X ³ has the same meaning as X ² and Y ² has the same meaning as Y ^1, and n represents an integer of 1 to 4. ] Are preferably used.

Here, the branched alkyl group represented by R ¹¹ in the general formulas (13) and (14) has a chemical structure represented by R ₃ C—, where R is a hydrogen atom, an alkyl group, At least one group selected from an alkyl group having a substituent, an aryl group and an aryl group having a substituent, and at least two groups are bonded to each other except when two of three Rs are hydrogen atoms. To form a ring structure. Examples thereof include a branched alkyl group such as a cycloalkyl group, an isopropyl group, and a t-butyl group, and an arylalkyl group such as a benzyl group.

Such quaternary phosphonium salts include:
For example, tetra (aryl) phosphonium hydroxides such as tetraphenylphosphonium hydroxide, tetranaphthylphosphonium hydroxide, tetra (chlorophenyl) phosphonium hydroxide, tetra (biphenyl) phosphonium hydroxide, tetratolylphosphonium hydroxide and tetrahexylphosphonium hydroxide And tetra (alkyl) phosphonium hydroxides, methyltriphenylphosphonium hydroxide, ethyltriphenylphosphonium hydroxide,
Propyltriphenylphosphonium hydroxide, butyltriphenylphosphonium hydroxide, octyltriphenylphosphonium hydroxide, tetradecyltriphenylphosphonium hydroxide, benzyltriphenylphosphonium hydroxide, ethoxybenzyltriphenylphosphonium hydroxide, methoxymethyltriphenylphosphonium hydroxy , Acetoxymethyltriphenylphosphonium hydroxide, phenacyltriphenylphosphonium hydroxide, chloromethyltriphenylphosphonium hydroxide, bromomethyltriphenylphosphonium hydroxide, biphenyltriphenylphosphonium hydroxide, naphthyltriphenylphosphonium hydroxide, chlorophenyltrioxide Phenylphospho Mono (aryl) triphenylphosphonium hydroxides such as sodium hydroxide, phenoxyphenyltriphenylphosphonium hydroxide, methoxyphenyltriphenylphosphonium hydroxide, acetoxyphenyltriphenylphosphonium hydroxide, naphthylphenyltriphenylphosphonium hydroxide and mono ( Alkyl) triphenylphosphonium hydroxides, phenyltrimethylphosphonium hydroxide, biphenyltrimethylphosphonium hydroxide, phenyltrihexylphosphonium hydroxide, mono (aryl) trialkylphosphonium hydroxides such as biphenyltrihexylphosphonium hydroxide, dimethyldiphenyl Phosphonium hydroxide, diethyldiphenyl Diaryldialkylphosphonium hydroxides such as suphonium hydroxide and di (biphenyl) diphenylphosphonium hydroxide, tetraphenylphosphonium tetraphenylborate, tetranaphthylphosphonium tetraphenylborate, tetra (chlorophenyl) phosphonium tetraphenylborate, tetra (biphenyl) phosphonium Tetraaryl phosphonium tetraphenyl borates such as tetraphenyl borate, tetratolyl phosphonium tetraphenyl borate, methyl triphenyl phosphonium tetraphenyl borate, ethyl triphenyl phosphonium tetraphenyl borate, propyl triphenyl phosphonium tetraphenyl borate, butyl triphenyl phosphonium tetraphenyl Borate, Octyltriphenylphosphonium tetraphenylborate, tetradecyltriphenylphosphonium tetraphenylborate, benzyltriphenylphosphonium tetraphenylborate, ethoxybenzyltriphenylphosphonium tetraphenylborate, methoxymethyltriphenylphosphonium tetraphenylborate, acetoxymethyltriphenylphosphonium tetraphenyl Borate, phenacyl triphenyl phosphonium tetraphenyl borate, chloromethyl triphenyl phosphonium tetraphenyl borate, bromomethyl triphenyl phosphonium tetraphenyl borate, biphenyl triphenyl phosphonium tetraphenyl borate, naphthyl triphenyl phosphonium tetraphenyl borate, chlorophenyl Mono (aryl) triphenylphosphonium tetraphenylborate and mono (alkyl) such as triphenylphosphonium tetraphenylborate, phenoxyphenyltriphenylphosphonium tetraphenylborate, acetoxyphenyltriphenylphosphonium tetraphenylborate and naphthylphenyltriphenylphosphonium tetraphenylborate ) Triarylphosphonium tetraphenylborate, phenyltrimethylphosphonium tetraphenylborate, biphenyltrimethylphosphonium tetraphenylborate, phenyltrihexylphosphonium tetraphenylborate, monoaryltrialkylphosphonium tetraphenylborate such as biphenyltrihexylphosphonium tetraphenylborate Over preparative include dimethyl diphenyl phosphonium tetraphenylborate, diethyl diphenyl phosphonium tetraphenylborate, di (biphenyl) diaryl dialkyl phosphonium tetraphenylborate such as diphenyl phosphonium tetraphenylborate and the like.

As the counter anion, an aryloxy group such as phenoxide, an alkyloxy group such as methoxide or ethoxide, an alkylcarbonyloxy group such as acetate or the like, or an aryloxy group such as benzoate, in place of the above hydroxide or tetraphenylborate. Examples include quaternary phosphonium salts having a halogen atom such as a carbonyloxy group, chloride, and bromide.

In addition to the compounds represented by the above general formula (13), compounds having a divalent counter anion represented by the general formula (14), for example, bis (tetraphenylphosphonium) carbonate, Quaternary phosphonium salts such as (biphenyltriphenylphosphonium) carbonate, bis-tetraphenylphosphonium salts of 2,2-bis (4-hydroxyphenyl) propane, ethylenebis (triphenylphosphonium) dibromide, trimethylenebis (triphenyl Phosphonium) -bis (tetraphenyl borate) and the like.

Further, the following general formulas (15) and (16)

[0066]

Embedded image [Formula (15), in (16), R ¹³ represents an organic group, X ⁴
Represents a halogen atom, a hydroxyl group, an alkyloxy group, an aryloxy group, an alkylcarbonyloxy group, an arylcarbonyloxy group, HCO ₃ — or —BR ₄ (where R
Represents a hydrogen atom or a hydrocarbon group, and the four Rs may be the same or different from each other. ). Ph represents a phenyl group; Y ³ represents —CO ₃ —;
Indicates an integer of 4. ] The compound represented by this is mentioned.

Specific examples of such a quaternary phosphonium compound include, for example, tetraphenylphosphonium hydroxide, biphenyltriphenylphosphonium hydroxide, methoxyphenyltriphenylphosphonium hydroxide, phenoxyphenyltriphenylphosphonium hydroxide, naphthylphenyltrihydroxide. Phenylphosphonium hydroxide, tetraphenylphosphonium tetraphenylborate, biphenyltriphenylphosphonium tetraphenylborate, methoxyphenyltriphenylphosphonium tetraphenylborate, phenoxyphenyltriphenylphosphonium tetraphenylborate, naphthylphenyltriphenylphosphonium tetraphenylborate, tetraphenylphosphonium Phenoxide, bi Phenyl triphenyl phosphonium phenoxide, methoxy phenyl triphenyl phosphonium phenoxide, phenoxy phenyl triphenyl phosphonium phenoxide, naphthyl phenyl triphenyl phosphonium phenoxide, tetraphenyl phosphonium chloride, biphenyl triphenyl phosphonium chloride, methoxy phenyl triphenyl phosphonium chloride, phenoxy phenyl triphenyl phosphonium Chloride or naphthylphenyltriphenylphosphonium chloride. Among these quaternary phosphonium salts, tetraphenylphosphonium tetraphenyl borate is preferably used because of its high catalytic activity and little remaining as impurities in the obtained polycarbonate.

Specific examples of the quaternary phosphonium salt containing a branched alkyl group include, for example, isopropyltrimethylphosphonium, isopropyltriethylphosphonium, isopropyltributylphosphonium, isopropyltriphenylphosphonium, tetraisopropylphosphonium, cyclohexyltriethylphosphonium,
Cyclohexyltrimethylphosphonium, cyclohexyltributylphosphonium, cyclohexyltriphenylphosphonium, tetracyclohexylphosphonium,
1,1,1-triphenylmethyltrimethylphosphonium, 1,1,1-triphenylmethyltriethylphosphonium, 1,1,1-triphenylmethyltributylphosphonium, 1,1,1-triphenylmethyltriphenylphosphonium and the like No.

Further, specific examples of X ⁴ relating to the counter anion in the compound represented by the above formula (15) include hydroxide, borohydride, tetraphenyl borate, acetate, propionate, fluoride, chloride, hydrocarbonate and the like. Can be mentioned. Specific examples of Y ^{3 in} the compound represented by the above formula (16) include carbonate and the like.

Specific examples of the salt comprising a quaternary phosphonium (cation) containing a branched alkyl group and X or Y (anion) include various ones from combinations of the above specific examples. Examples include phosphonium hydroxide, cyclohexyltriphenylphosphonium chloride, 1,1,1-triphenylmethyltriethylphosphonium acetate, and bis (isopropyltriethylphosphonium) carbonate. Among these compounds, cyclohexyltriphenylphosphonium tetraphenylborate and cyclopentyltriphenylphosphonium tetraphenylborate are preferably used.

Further, tetramethylphosphonium acetate, tetraethylphosphonium acetate, tetrapropylphosphonium acetate, tetrabutylphosphonium acetate, tetrapentylphosphonium acetate, tetrahexylphosphonium acetate, tetraheptylphosphonium acetate, tetraoctylphosphonium acetate, tetradecylphosphonium acetate, Tetradodecylphosphonium acetate, tetratolylphosphonium acetate, tetraphenylphosphonium acetate, tetramethylphosphonium benzoate, tetraethylphosphonium benzoate, tetrapropylphosphonium benzoate, tetraphenylphosphonium benzoate, tetramethylphosphonium formate, tetra Tylphosphonium formate, tetrapropylphosphonium formate, tetraphenylphosphonium formate, tetramethylphosphonium propionate, tetraethylphosphonium propionate, tetrapropylphosphonium propionate, tetramethylphosphonium butyrate, tetraethylphosphonium butyrate, tetrapropyl Carboxylates such as phosphonium butyrate can also be mentioned.

Next, when performing the solid-phase polymerization of the polycarbonate prepolymer using the quaternary phosphonium salt as a catalyst, a quaternary phosphonium salt having a low content of metal impurities is preferable, particularly an alkali metal compound and an alkali metal compound. The content of the earth metal compound is 50ppm
Or less, preferably 30 ppm or less, more preferably 1 ppm or less.
Those having a concentration of 0 ppm or less are preferably used. And
The use ratio of this catalyst is preferably 10 ^-2 to 10 ^-8 mol per 1 mol of the dihydroxy compound as the raw material.
If the use ratio of this catalyst is less than 10 ^-8 mol, the catalytic activity in the latter stage of the reaction may be insufficient, and if it exceeds 10 ^-2 mol, the quality of the polycarbonate may be deteriorated or economically disadvantageous. Because there is.

When the solid phase polymerization is carried out in a solid state of the polycarbonate prepolymer, a polymerization reaction is carried out by using the quaternary phosphonium salt as a catalyst on the solid polycarbonate prepolymer subjected to the crystallization treatment. . In this step, the aromatic monohydroxy compound, diaryl carbonate, or both, which are by-produced by the polymerization reaction, are extracted out of the system to promote the reaction. Therefore, an inert gas such as carbon dioxide gas, nitrogen gas, argon gas, and helium gas, or a hydrocarbon gas or poor solvent vapor that can be completely removed is introduced into the reaction system, and aromatic gas is caused to accompany these gases. A method of removing a hydroxy compound or the like, a method of performing a polymerization reaction under reduced pressure, or a method using both of them can be employed. It is desirable that the accompanying gas be introduced by heating to a temperature close to the reaction temperature. When a hydrocarbon gas or a poor solvent vapor is used, a hydrocarbon having a low solubility of polycarbonate, having no involvement in the reaction, and having a low boiling point and a completely removable carbon number of 4 to 18 is preferable. .

The shape of the crystallized prepolymer for carrying out the solid-state polymerization reaction is not particularly limited, but is preferably in the form of powder, granules, pellets, beads or the like. . As for the method of adding the catalyst to the crystallized prepolymer, as described above, the catalyst may be added in the prepolymer production step, and the remaining one may be used as it is or may be added in the crystallization step. .

Regarding the reaction temperature and the reaction time for carrying out this solid-state polymerization reaction, the chemical structure and molecular weight of the crystallized prepolymer, the crystallinity, the particle shape, the type and amount of the catalyst, and the amount of the product polycarbonate Although it depends on the required characteristics and the like, the reaction temperature is preferably not lower than the glass transition temperature of the product polycarbonate and in a range in which the crystallized prepolymer during the solid phase polymerization is maintained in a solid state without melting. More preferably, the temperature is at least 50 ° C. lower than the melting temperature of the crystallized prepolymer and lower than the melting temperature. For example, as raw material 2,
In the case of a crystallized prepolymer prepared using 2-bis (4-hydroxyphenyl) propane and diphenyl carbonate, 150-260 ° C, preferably 180-2 ° C.
45 ° C. It is also preferable to increase the solid-state polymerization temperature in accordance with the increase in the melting temperature of the crystallized prepolymer during the solid-state polymerization. On the other hand, regarding the reaction time,
The period is from minutes to 100 hours, preferably from 0.1 to 50 hours.
Furthermore, in order to uniformly heat the crystallized prepolymer in the course of the polymerization in this polymerization step, and to extract by-products more effectively, stirring the contents of the reactor or rotating the reactor, Alternatively, a method of causing the contents to flow by a heated gas may be employed.

The polycarbonate of the product thus obtained has a viscosity average molecular weight of 10,000 to
It is 40,000, and has a molecular weight equivalent to that of polycarbonate generally used industrially. Further, the crystallinity of this product polycarbonate is higher than that of the prepolymer used as the raw material. And since this product polycarbonate is obtained as a powder of crystalline polycarbonate, the powder may be supplied to an extruder without cooling and may be pelletized, or may be directly supplied to a molding machine to be molded. You may.

When various additives are blended,
The additive powder may be mixed, a liquid of the additive may be sprayed, or a gas may be absorbed. Further, additives may be mixed with an extruder during pelletization of polycarbonate. There are no particular restrictions on the additives that can be added to the polycarbonate of this product, and commonly used additives such as plasticizers, pigments, lubricants, mold release agents, stabilizers, and inorganic fillers are used. Can also be used. This polycarbonate can be used as a resin composition by blending with a polymer such as polyolefin, polystyrene, polyester, polysulfonate, polyamide, polyphenylene ether, or polyacrylate. In this case, as the compounding resin, polyphenylene ether or polyether nitrile having a functional group such as a hydroxyl group, a carbonyl group, or an amino group at a molecular chain terminal, a terminal-modified polysiloxane compound, a modified polypropylene, a modified polystyrene, or the like is used. Solubility is improved and effective.

[0078]

[Example 1]

(1) Preparation of Polycarbonate Prepolymer In a nickel steel autoclave with an internal volume of 1 liter and equipped with a stirrer, 228 g (1.0 mol) of 2,2-bis (4-hydroxyphenyl) propane as a hydroxy compound was added.
225 g of diphenyl carbonate as carbonic acid diester
(1.15 mol), and a concentration of tetramethylammonium hydroxide as a catalyst for producing a prepolymer of 20.
0.23 ml (0.5 mmol) of a 0.2% by mass aqueous solution and 0.0066 g of tetraphenylphosphonium tetraphenylborate (0.
01 mmol) and the atmosphere was replaced with nitrogen gas five times.

Next, the mixture in the autoclave was heated to 190 ° C. and reacted in a nitrogen gas atmosphere for 30 minutes. Then, the temperature was gradually increased to 235 ° C., and at the same time, the degree of vacuum was increased to 8.00 kPa to react for 60 minutes. Further, the temperature was gradually increased to 270 ° C., and at the same time, the degree of vacuum was increased to 1.33 kPa. The reaction was performed for 120 minutes. Next, the vacuum was reduced to 0.
After raising the pressure to 133 kPa and reacting for 30 minutes, the degree of vacuum was raised to 0.0665 kPa and the reaction was further performed for 30 minutes. After the completion of the reaction, a part of the produced prepolymer was taken out of the autoclave as a physical property measurement sample. The viscosity average molecular weight of the obtained polycarbonate prepolymer was 8,600, and the terminal fraction of hydroxyl group terminals determined by ¹ H-NMR measurement was 30 mol%.

(2) Crystallization of Polycarbonate Prepolymer Subsequently, about 3 kg of liquefied carbon dioxide was injected into the autoclave containing the prepolymer, and the mixture was stirred at 150 ° C. for 30 minutes. Thereafter, carbon dioxide was extracted from the outlet of the autoclave. At this time, carbon dioxide was recovered as a gas.

The crystallinity of the crystallized polycarbonate prepolymer obtained here was measured by measuring the endothermic enthalpy at the melting point with a differential scanning calorimeter. For the endothermic enthalpy of this crystallization, refer to the literature [Polymer Letters, 8645].
(1970)] value, which is an endothermic enthalpy at the time of 100% crystallization of 109.7 J / g. The measurement by the differential scanning calorimeter was performed with a sample amount of 10 mg and a heating rate of 40 ° C./min from 50 ° C. to 300 ° C. As a result, it was confirmed that the crystallinity of the crystallized polycarbonate prepolymer was 25%.

(3) Solid State Polymerization of Crystallized Polycarbonate Prepolymer Next, 15 g of the powder of the crystallized polycarbonate prepolymer obtained above was charged with 58 mm in diameter and 170 mm in length.
Into a stainless steel tubular reactor of
While flowing at a flow rate of milliliters / minute,
The product polycarbonate was obtained by raising the temperature to 40 ° C. and performing solid-state polymerization for 2 hours. The viscosity average molecular weight of the product polycarbonate obtained here was 22,900, and the content of the residual solvent in the product polycarbonate was measured to be 0 ppm. The content of the residual solvent was measured by extracting the product polycarbonate by heating with toluene, and measuring the extract by gas chromatography absolute calibration curve method.

(4) Evaluation of Thermal Stability of Product Polycarbonate To evaluate the thermal stability of product polycarbonate, the yellow index (shown by YI in Table 1) of the polycarbonate obtained in (3) above. Of the polycarbonate at 340 ° C.
The difference from the measured value after heat treatment for 0 minute ((ΔY in Table 1)
Indicated by I. ) Was used as an index of thermal stability. The yellow index was measured by taking an 8% by mass methylene chloride solution of polycarbonate in a quartz cell having a height of 57 mm and using a color meter SM-3 manufactured by Suga Test Instruments Co., Ltd. The above results are summarized in Table 1.

Example 2 Example 2 was carried out in the same manner as in Example 1 except that the crystallization time in (2) of Example 1 was changed to 60 minutes. Table 1 shows the physical properties and evaluation results of the polycarbonate prepolymer and the product polycarbonate.

Example 3 Example 3 was the same as Example 1 except that the crystallization time in (2) of Example 1 was changed to 120 minutes. Table 1 shows the physical properties and evaluation results of the polycarbonate prepolymer and the product polycarbonate.

Example 4 A polycarbonate prepolymer was prepared in the same manner as in (1) of Example 1, and the obtained polycarbonate prepolymer was extracted in a molten state, and then cooled to room temperature and solidified. Next, the obtained solid polycarbonate prepolymer was crushed,
After passing through a sieve of × 4 mm, 300 g of the polycarbonate prepolymer solid particles having passed through the sieve were put into a tubular reaction tube having a capacity of 500 ml and capable of introducing liquefied carbon dioxide. Then, liquefied carbon dioxide was introduced into the reaction tube, and the reaction tube was sealed. Thereafter, the temperature of the reaction tube was raised to 150 ° C., and crystallization treatment was performed at this temperature for 60 minutes. The thus obtained polycarbonate prepolymer was whitened, and it could be visually confirmed that it was crystallized. Using the crystalline polycarbonate prepolymer obtained here, solid-phase polymerization was performed in the same manner as in (3) of Example 1. Table 1 shows the physical properties and evaluation results of the polycarbonate prepolymer and the product polycarbonate.

Comparative Example 1 (1) Preparation of Polycarbonate Prepolymer A polycarbonate prepolymer was prepared in the same manner as in Example 1, (1). The viscosity average molecular weight of the obtained polycarbonate prepolymer was 8,300, and the terminal fraction of hydroxyl group terminals was 32 mol%.

(2) Crystallization of the polycarbonate prepolymer The polycarbonate prepolymer 3 obtained in the above (1)
0 g was dissolved in 100 ml of methylene chloride at room temperature, 30 ml of acetone was added as a poor solvent, and the solvent was removed with an evaporator to obtain 29 g of a crystallized polycarbonate prepolymer. The crystallinity of the crystallized polycarbonate prepolymer obtained here was 29%.

(3) Solid-phase polymerization of the crystallized polycarbonate prepolymer The solid-phase polymerization of the crystallized polycarbonate prepolymer obtained in the above (2) was carried out in the same manner as in Example 1, (3) except that the product was used. Polycarbonate was obtained. When the content of the residual solvent in this product polycarbonate was measured, it was confirmed that it contained 100 ppm of methylene chloride.

(4) Evaluation of Thermal Stability of Product Polycarbonate Evaluation of thermal stability of product polycarbonate was performed in the same manner as (4) of Example 1 except that the product polycarbonate obtained in (3) was used. did. Table 1 shows the above results.

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[Table 1]

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According to the present invention, it is possible to provide a method for producing a polycarbonate which is substantially free of residual solvent and has excellent heat stability.

Claims (6)

[Claims] Claims: 1. A method for producing a polycarbonate by converting a polycarbonate prepolymer into a high molecular weight in a solid state, wherein the polycarbonate prepolymer is crystallized by contacting it with carbon dioxide in a liquid, subcritical or supercritical state. A method for producing a polycarbonate, comprising solid-state polymerization. 2. The method for producing a polycarbonate according to claim 1, wherein the viscosity average molecular weight of the polycarbonate prepolymer is 2,000 to 20,000. 3. The process for producing a polycarbonate according to claim 1, wherein the solid phase polymerization is carried out in the presence of a quaternary phosphonium salt catalyst. 4. The method for producing a polycarbonate according to claim 1, wherein the polycarbonate prepolymer is obtained by a transesterification method between a dihydroxy compound and a carbonic acid diester. 5. The method of claim 1, wherein the polycarbonate prepolymer is a liquid,
The method for producing a polycarbonate according to any one of claims 1 to 4, wherein the crystallization is performed by contacting with carbon dioxide in a subcritical or supercritical state, and then carbon dioxide is separated by reducing the pressure. 6. The carbon dioxide used for crystallization of the polycarbonate prepolymer is recovered and recycled.
A method for producing a polycarbonate according to any one of claims 1 to 5.