JP2001247671A - Method for producing polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polycarbonate wherein the treating time of a thermal crystallization treatment can be shortened. SOLUTION: Before a substantially amorphous prepolymer in a solid phase having a viscosity average mol.wt. of 2,000-20,000 is converted into a high-mol.- wt. polymer, (1) the prepolymer is crystallized by heating at a temperature equal to or higher than the melting point of the prepolymer before heated; (2) the prepolymer is crystallized by heating under such conditions as to cause the crystallization from the amorphous state to occur; or (3) the prepolymer is crystallized by heating at a temperature in the range of 195-230 deg.C from the early stage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polycarbonate, and more particularly to a method for producing a polycarbonate in which a crystallization step is improved in a solid-state polymerization method.

[0002]

2. Description of the Related Art Polycarbonate is widely used as an excellent engineering plastic in various fields. As a production method, a method of directly reacting an aromatic dihydroxy compound such as bisphenol A with phosgene (interfacial method) or a method of producing bisphenol A method in which an aromatic dihydroxy compound such as A is transesterified with a carbonic acid diester such as diphenyl carbonate in a molten state (melting method), or after partially crystallizing an amorphous prepolymer prepared by a melting method. A method for increasing the molecular weight by solid phase polymerization (solid phase method) is known.

However, in the interfacial method, toxic phosgene must be used, the apparatus is corroded by a chlorine-containing compound such as hydrogen chloride or sodium chloride produced as a by-product, and the removal of methylene chloride mixed in the resin is extremely difficult. There is a problem that chlorine is easily contained in polycarbonate which is difficult to obtain.

[0004] On the other hand, although the melting method solves the above problems in the interfacial method, in this method, a hydroxy compound and finally a carbonic acid diester are distilled off from a high-viscosity polycarbonate melt. It is necessary to carry out the reaction for a long time under high temperature and high vacuum because the degree of polymerization does not increase unless it is performed. Therefore, (1) Special equipment suitable for high temperature and high vacuum and high viscosity of the product A strong stirring device is required, (2) the molecular weight is not sufficiently high with a reactor and a stirrer usually used in the plastics industry, and (3) a branch is caused by a side reaction in order to react at a high temperature. It has various drawbacks, such as that a polymer having good quality is difficult to be obtained due to easy cross-linking, and (4) coloring cannot be avoided due to long-term stay at high temperature. Furthermore, the polycarbonate obtained by this melting method contains a large amount of low molecular weight components such as residual monomers and acetone-soluble components in the produced polymer, which causes problems such as a reduction in impact strength and adhesion to a mold. there were.

Although the solid phase method can solve the problems of the melting method, there is a problem in the crystallization step of the amorphous prepolymer obtained in the prepolymer preparation step. That is, the obtained amorphous prepolymer has a melting point lower than the polymerization temperature at which solid phase polymerization can be performed, and even if the polymerization is attempted in an amorphous state, the prepolymer is fused. Impossible.
Therefore, in order to carry out polymerization in a solid state, a crystallization step for crystallizing an amorphous prepolymer is required. The crystallization method includes a solvent treatment method and a heat treatment method (JP-A-1-158033, JP-A-4-359017). However, the solvent treatment method has a problem that a recovery system is required. Regarding the heat treatment method, the invention described in Japanese Patent Application Laid-Open No. 1-158033 discloses that the prepolymer is crystallized to some extent, and returns to an amorphous state by heat treatment at a temperature higher than the melting temperature of the prepolymer. The heat treatment must be performed at a temperature lower than the melting temperature of the prepolymer (increase with time) until the heat treatment is performed at a relatively low temperature, and the treatment time is long (Example 16 for 15 hours).

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and has as its object to provide a method for producing a polycarbonate including a heat crystallization treatment capable of shortening the treatment time.

[0007]

Means for Solving the Problems As a result of extensive studies, the present inventors have heated the amorphous polycarbonate prepolymer obtained in the prepolymer preparation step at a relatively high temperature from the initial stage to crystallize it. Surprisingly, the inventors have found that the object of the present invention can be effectively achieved by the treatment, and have completed the present invention.

That is, the gist of the present invention is as follows. 1. Prior to increasing the molecular weight of the substantially amorphous polycarbonate prepolymer having a viscosity average molecular weight of 2,000 to 20,000 in the solid state, the prepolymer is heated at a temperature not lower than the melting temperature of the prepolymer before the heat treatment. A method for producing a polycarbonate, comprising crystallization by heat treatment. 2. Prior to increasing the molecular weight of the substantially amorphous polycarbonate prepolymer having a viscosity average molecular weight of 2,000 to 20,000 in the solid state, the prepolymer is heated under heating conditions under which crystallization occurs from the amorphous state. A process for producing a polycarbonate, comprising treating and crystallizing. 3. Prior to increasing the molecular weight of the substantially amorphous polycarbonate prepolymer having a viscosity average molecular weight of 2,000 to 20,000 in the solid state, the prepolymer is heated from an initial stage at a temperature in the range of 195 to 230 ° C. A process for producing a polycarbonate, comprising treating and crystallizing. 4. 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.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a prepolymer preparation step (hereinafter, referred to as a prepolymerization step), a heat crystallization step,
It comprises a solid-state polymerization step and has a feature in the heat crystallization step. (1) Preliminary Polymerization Step The polymerization method is not particularly limited as long as an amorphous prepolymer can be obtained, and a preferable method is a melting method. First, an amorphous polycarbonate prepolymer is prepared by preliminary polymerization. In this melting method, (A)
A prepolymer is prepared using a dihydroxy compound, (B) a carbonic acid diester, and if necessary, a comonomer such as a (C) terminal terminator or (D) a branching agent. At this time, as the polymerization catalyst, at least one selected from (E) a nitrogen-containing organic basic compound and (F) a phosphorus-containing basic compound is preferably used.

First, the components (A) to (D) of the raw material and the components (E) and (F) of the catalyst will be described. (A) Dihydroxy compound The dihydro compound includes an aromatic dihydroxy compound and an aliphatic dihydroxy compound, and an aromatic dihydroxy compound is preferable. Usually, the aliphatic dihydroxy compound is used by being mixed with the aromatic dihydroxy compound. The aromatic dihydroxy compound has the general formula (I)

[0011]

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The compounds represented by the following formulas can be mentioned.
In the general formula (I), R ¹ and R ² each represent a halogen atom of fluorine, chlorine, bromine, or iodine or an alkyl group having 1 to 8 carbon atoms, for example, a methyl group, an ethyl group, an n-
Propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl,
It represents a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, or the like. R ¹ and R ² may be the same or different. The plurality of R ¹ is when R ¹ are a plurality may be the same or different, a plurality of R ² if R ² there are a plurality may be the same or different. m and n are each an integer of 0-4. 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, or -S-, −
SO—, —SO ₂ —, —O—, —CO— bond or formula (II), (II ′)

[0013]

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[0014] The bond represented by Examples of the alkylene group having 1 to 8 carbon atoms and the alkylidene group having 2 to 8 carbon atoms include:
Examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, an ethylidene group, an isopropylidene group and the like. As a cycloalkylene group having 5 to 15 carbon atoms and a cycloalkylidene group having 5 to 15 carbon atoms, Examples thereof include a cyclopentylene group, a cyclohexylene group, a cyclopentylidene group, and a cyclohexylidene group.

Examples of the aromatic dihydroxy compound represented by the above general formula (I) include bis (4-hydroxyphenyl) methane; bis (3-methyl-4-hydroxyphenyl) methane; and bis (3-chloro-4). -Hydroxyphenyl) methane; bis (3,5-dibromo-4-hydroxyphenyl) methane; 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 (commonly known as bisphenol A); 2,2-bis (3-methyl-4-hydroxyphenyl) propane; 2,2-bis (2-methyl-4-hydroxyphenyl) propane;
2,2-bis (3,5-dimethyl-4-hydroxyphenyl) 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; 2,2 -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 (4-hydroxyphenyl) butane; 2,2-bis (4-hydroxyphenyl) octane; 2,2 -Bis (4-hydroxyphenyl) phenylmethane; 2,2-bis (4-hydroxy-1-methylphenyl) propane; 1,1-bis (4
-Hydroxy-t-butylphenyl) propane; 2,2
-Bis (4-hydroxy-3-bromophenyl) propane; 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane; 2,2-bis (4-hydroxy-
3-chlorophenyl) propane; 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane;
2-bis (4-hydroxy-3,5-dibromophenyl) propane; 2,2-bis (3-bromo-4-hydroxy-5-chlorophenyl) propane; 2,2-bis (3-phenyl-4-hydroxy Phenyl) propane;
2,2-bis (4-hydroxyphenyl) butane; 2,
2-bis (3-methyl-4-hydroxyphenyl) butane; 1,1-bis (2-butyl-4-hydroxy-5-
1,1-bis (2-t-butyl-4-hydroxy-5-methylphenyl) butane;
1,1-bis (2-t-butyl-4-hydroxy-5-
Methylphenyl) isobutane; 1,1-bis (2-t-
Amyl-4-hydroxy-5-methylphenyl) 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 (2-t
-Butyl-4-hydroxy-5-methylphenyl) heptane; 2,2-bis (4-hydroxyphenyl) octane; bis (hydroxyaryl) alkanes such as 1,1- (4-hydroxyphenyl) ethane; 1-bis (4-hydroxyphenyl) cyclopentane; 1,1-
Bis (4-hydroxyphenyl) cyclohexane; 1,
1-bis (3-methyl-4-hydroxyphenyl) cyclohexane; 1,1-bis (3-cyclohexyl-4-)
1,1-bis (3-phenyl-4-hydroxyphenyl) cyclohexane; 1,1-bis (4-hydroxyphenyl) -3,
Bis (hydroxyaryl) cycloalkanes such as 5,5-trimethylcyclohexane; bis (4-hydroxyphenyl) ether; bis (hydroxyaryl) ethers such as bis (4-hydroxy-3-methylphenyl) ether; 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;
4,4'-dihydroxy-2,2'-dimethylbiphenyl;4,4'-dihydroxy-3,3'-dimethylbiphenyl;4,4'-dihydroxy-3,3'-dicyclohexylbiphenyl;
And dihydroxybiphenyls such as 3,3'-difluoro-4,4'-dihydroxybiphenyl.

Examples of the aromatic dihydroxy compound other than the general formula (I) include dihydroxybenzenes, halogen- and alkyl-substituted dihydroxybenzenes.
For example, resorcin, 3-methyl resorcin, 3-ethyl resorcin, 3-propyl resorcin, 3-butyl resorcin, 3-t-butyl resorcin, 3-phenyl resorcin, 3-cumyl resorcin; 2,3,4,6- Tetrafluororesorcin; 2,3,4,6-tetrabromoresorcin; catechol, hydroquinone, 3-methylhydroquinone, 3-ethylhydroquinone, 3-propylhydroquinone, 3-butylhydroquinone, 3
-T-butylhydroquinone, 3-phenylhydroquinone, 3-cumylhydroquinone; 2,5-dichlorohydroquinone; 2,3,5,6-tetramethylhydroquinone; 2,3,4,6-tetra-t-butylhydroquinone 2,3,5,6-tetrafluorohydroquinone; and 2,3,5,6-tetrabromohydroquinone.

Next, there are various aliphatic dihydroxy compounds. For example, butane-1,4-diol; 2,2-dimethylpropane-1,3-diol;
Hexane-1,6-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 ethoxy of a dihydric alcohol or phenol Or propoxylation products such as bis-oxyethyl-bisphenol A; bis-oxyethyl-tetrachlorobisphenol A or bis-oxyethyl-tetrachlorohydroquinone.
In the preferred production method of the present invention, one or more of the above compounds are appropriately selected and used as the dihydroxy compound as the component (A), and among these, bisphenol A which is an aromatic dihydroxy compound is used. Is preferred.

Further, diesters of dihydroxy compounds, dicarbonates of dihydroxy compounds, monocarbonates of dihydroxy compounds and the like can also be used. That is, examples of diesters of dihydroxy compounds include diacetate of bisphenol A, dipropionate of bisphenol A, dibutylate of bisphenol A, and dibenzoate of bisphenol A.

Examples of dicarbonates of dihydroxy compounds include bismethyl carbonate of bisphenol A, bisethyl carbonate of bisphenol A, and bisphenyl carbonate of bisphenol A. Examples of monocarbonates of the dihydroxy compound include bisphenol A monomethyl carbonate, bisphenol A monoethyl carbonate, bisphenol A monopropyl carbonate, and bisphenol A monophenyl carbonate.

(B) Dicarbonate Various types are used. For example, it is at least one compound selected from diaryl carbonate compounds, dialkyl carbonate compounds and alkylaryl carbonate compounds. The diaryl carbonate compound used as one of the components (B) has the general formula (III)

[0021]

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Wherein Ar ¹ and Ar ² each represent an aryl group, which may be the same or different, or a compound represented by the general formula (IV)

[0023]

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(Wherein, Ar ³ and Ar ⁴ each represent an aryl group, which may be the same or different, and D ¹ represents a residue obtained by removing two hydroxyl groups from the aromatic dihydroxy compound. ). The dialkyl carbonate compound is represented by the general formula (V)

[0025]

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(Wherein R ³ and R ⁴ each have 1 carbon atom)
Represents an alkyl group having from 6 to 6 or a cycloalkyl group having from 4 to 7 carbon atoms, which may be the same or different. Or a compound represented by the general formula (VI)

[0027]

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Wherein R ⁵ and R ⁶ each have 1 carbon atom
And a cycloalkyl group having 4 to 7 carbon atoms, which may be the same or different, and D ² represents a hydroxyl group 2 from the aromatic dihydroxy compound.
The residue excluding the number is shown. ). The alkylaryl carbonate compound is represented by the general formula (VII)

[0029]

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(Wherein, Ar ⁵ represents an aryl group, R ⁷ represents an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 4 to 7 carbon atoms), or a compound represented by the general formula (VII)
I)

[0031]

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(Wherein, Ar ⁶ is an aryl group, R ⁸ is an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 4 to 7 carbon atoms, and D ³ is a group obtained by removing two hydroxyl groups from the aromatic dihydroxy compound. The compound is a compound represented by the following formula:

Here, as the diaryl carbonate compound,
For example, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, bisphenol A bisphenyl carbonate and the like can be mentioned. Examples of the dialkyl carbonate compound include diethyl carbonate, dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, and bisphenol A bismethyl carbonate.

Examples of the alkylaryl carbonate compound include methyl phenyl carbonate, ethyl phenyl carbonate, butyl phenyl carbonate, cyclohexyl phenyl carbonate, and bisphenol A methyl phenyl carbonate. In the present invention, one or more of the above compounds are appropriately selected and used as the diester carbonate (B), and among these, diphenyl carbonate is preferably used.

(C) Terminal terminator Examples of the terminal terminator include on-butylphenol; mn-butylphenol; pn-butylphenol; o-isobutylphenol; m-isobutylphenol; o-t-butylphenol; mt-butylphenol; pt-butylphenol; on-pentylphenol; mn-pentylphenol; pn-pentylphenol;
n-hexylphenol; mn-hexylphenol; pn-hexylphenol; o-cyclohexylphenol; m-cyclohexylphenol; p-cyclohexylphenol; o-phenylphenol;
Phenylphenol; p-phenylphenol; on
-Nonylphenol; mn-nonylphenol; p-
n-nonylphenol; o-cumylphenol; m-cumylphenol; p-cumylphenol; o-naphthylphenol; m-naphthylphenol; p-naphthylphenol; 2,6-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 And the like. These may be used alone or in combination of two or more. Among these, in particular, 2,6-di-t-butylphenol; 2,5-di-t-butylphenol; 2,4-di-butylphenol
3,5-dicumylphenol; 3,5-dicumylphenol; pt-butylphenol; p-cumylphenol; pt-octylphenol; Phenylphenol is preferred.

(D) Comonomer such as a branching agent As the comonomer, a compound having a functional group 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 can be used. Among them, a polyfunctional organic compound having three or more functional groups is used as the branching agent. Specifically, 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, for example, phloroglucin; melitic acid; trimellitic acid Trimellitic anhydride; trimellitic anhydride; gallic acid; n-propyl gallate; protocatechuic acid; pyromellitic acid; pyromellitic dianhydride; α-resorcinic acid; β-resorcinic acid; Chloride; trimethyl trichloride; 4-chloroformyl phthalic 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-triisopropylbenzene; 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 can be mentioned. These branching agents may be used alone or in combination of two or more.

Among them, 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-
Tris (4-hydroxy-3-methylphenyl) 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 preferred. Also, as other comonomers,
Examples thereof include 1,4-butanediol, terephthalic acid, and polydimethylsiloxane having a hydroxyl group at a terminal.

(E) Nitrogen-Containing Organic Basic Compound The nitrogen-containing organic basic compound is not particularly limited, and examples thereof include an aliphatic tertiary amine compound, an aromatic tertiary amine compound, and a nitrogen-containing heterocyclic compound. No. further,
Formula _{^{(IX) (NR 9 4)}} + (X 1) - quaternary ammonium salt represented by · · · (IX) can be mentioned.

In the above formula (IX), R ⁹ is an organic group, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a cyclohexyl group, a cycloalkyl group; Examples thereof include an aryl group such as a phenyl group, a tolyl group, a naphthyl group, and a biphenyl group, and an arylalkyl group such as a benzyl group. The four R ^{9 's} may be the same or different, and two R ^{9' s} may combine to form a ring structure. X ¹ is a halogen atom, a hydroxyl group, an alkyloxy group, an aryloxy group, R′COO, HCO ₃ , (R ′
O) shows the ₂ P (= O) O or BR '' ₄ 1 monovalent anion forming group capable of such. Here, R 'represents a hydrocarbon group such as an alkyl group or an aryl group, and two R'Os may be the same or different. R '' represents a hydrogen atom or a hydrocarbon group such as an alkyl group or an aryl group,
The four R ″ s may be the same or different.

As such a quaternary ammonium salt,
For example, ammonium hydroxides having an alkyl group, an aryl group, an araryl group and the like, such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, trimethylbenzylammonium hydroxide, tetramethylammonium borohydride, tetrabutylammonium Examples include basic salts such as borohydride, tetrabutylammonium tetraphenylborate, and tetramethylammonium tetraphenylborate.

Among these nitrogen-containing organic basic compounds,
Quaternary ammonium salts represented by the above general formula (IX), such as tetramethylammonium hydroxide and tetrabutylammonium, have high catalytic activity, are easily thermally decomposed, and do not easily remain in the polymer. Hydroxide, tetramethylammonium borohydride and tetrabutylammonium borohydride are preferred, and tetramethylammonium hydroxide is particularly preferred. Such a nitrogen-containing organic basic compound may be used alone or in combination of two or more.

(F) Phosphorus-Containing Basic Compound The phosphorus-containing basic compound is not particularly limited, but a quaternary phosphonium salt compound is preferably used. The quaternary phosphonium salt is not particularly limited, there are various things, but for example the general formula (X) or _{^{(XI) (PR 10 4)}} + (X 2) - ·· (X) (PR 10 4) ^{+ ₂} (Y ^{1) 2-} compounds represented by · · · (XI) is preferably used.

In the above general formula (X) or (XI), R
Reference numeral ¹⁰ denotes an organic group. Examples of the organic group include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a cyclohexyl group, a cycloalkyl group, a phenyl group, and a tolyl group. Groups, naphthyl groups, aryl groups such as biphenyl groups, and arylalkyl groups such as benzyl groups. Four R ¹⁰ may be the same with or different from each other, or may form a ring structure by bonding two R ^10. X
² can be mentioned those similar to the X ^1. Y ¹
Represents a group capable of forming a divalent anion such as CO ₃ .

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 hydroxy (Aryl or alkyl) phosphonium hydroxides such as tetramethylphosphonium tetraphenylborate, tetraphenylphosphonium bromide, tetraphenylphosphonium phenolate, tetraphenylphosphonium tetraphenylborate, methyltriphenylphosphonium tetraphenylborate, benzyl Triphenylphosphonium La tetraphenylborate, biphenyl triphenylphosphonium tetraphenylborate, tetra-tolyl phosphonium tetraphenylborate, tetraphenylphosphonium phenolate, tetra (p-t
-Butylphenyl) phosphonium diphenyl phosphate, triphenylbutylphosphonium phenolate, triphenylbutylphosphonium tetraphenylborate and the like.

Among these quaternary phosphonium salts, phosphonium salts having an alkyl group, specifically tetramethylphosphonium, are preferred because of their high catalytic activity, easy thermal decomposition, and low persistence in the polymer. Methyl triphenyl borate, tetraethyl phosphonium ethyl triphenyl borate, tetrapropyl phosphonium propyl triphenyl borate, tetrabutyl phosphonium butyl triphenyl borate, tetrabutyl phosphonium tetraphenyl borate, tetraethyl phosphonium tetraphenyl borate, trimethyl ethyl phosphonium trimethyl phenyl borate, trimethyl benzyl Phosphonium benzyl triphenyl borate and the like are preferred.

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

In addition to the compounds represented by the above general formula (X) or (XI), for example, bis-tetraphenylphosphonium salt of 2,2-bis (4-hydroxyphenyl) propane, ethylenebis (triphenylphosphonium) ) Dibromide, trimethylenebis (triphenylphosphonium) -bis (tetraphenylborate) and the like.

Further, a quaternary phosphonium salt having an aryl group and / or a branched alkyl group can also be used. For example, the general formula _{^{(XII) (R 11 n PR}} 12 4-n) + (X 3) - ···· (XII) or the general formula _{^{(XIII) (R 11 n PR}} 12 4-n) + 2 ( Y ² ) The compound represented by ^2- (XIII) is used.

In the above general formula (XII) or (XIII),
n represents an integer of 1 to 4, and R ¹¹ represents at least one selected from an aryl group and a branched alkyl group. The branched alkyl group has a structure of “R ₃ C—”, wherein R is selected from hydrogen, an alkyl group, an alkyl group having a substituent, an aryl group, and an aryl group having a substituent. It is at least one, and at least two of the three Rs may combine to form a ring structure. However, this excludes the case where two are hydrogen at the same time. 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. When n is 2 or more, R may be the same or different. R ¹² represents an alkyl group, an alkyl group having a substituent, an aryl group, or an aryl group having a substituent. X ³ is a halogen atom, a hydroxyl group, an alkyloxy group, an aryloxy group, R′COO, HCO ₃ ,
A group capable of forming a monovalent anion such as (R′O) ₂ P (＝ O) O or BR ″ ₄ is shown. Here, R ′ represents a hydrocarbon group such as an alkyl group or an aryl group, and two R′O
They may be the same or different. R ″ represents a hydrogen atom or a hydrocarbon group such as an alkyl group or an aryl group, and the four R ″ s may be the same or different. Y ² represents a group capable of forming a divalent anion such as CO ₃ .

Such quaternary phosphonium salts include:
For example, tetra (aryl or alkyl) phosphonium hydroxy such as tetraphenylphosphonium hydroxide, tetranaphthylphosphonium hydroxide, tetra (chlorophenyl) phosphonium hydroxide, tetra (biphenyl) phosphonium hydroxide, tetratolylphosphonium hydroxide and tetrahexylphosphonium hydroxide Compounds, methyltriphenylphosphonium hydroxide, ethyltriphenylphosphonium hydroxide, propyltriphenylphosphonium hydroxide, butyltriphenylphosphonium hydroxide,
Octyltriphenylphosphonium hydroxide, tetradecyltriphenylphosphonium hydroxide, benzyltriphenylphosphonium hydroxide, ethoxybenzyltriphenylphosphonium hydroxide, methoxymethyltriphenylphosphonium hydroxide, acetoxymethyltriphenylphosphonium hydroxide, phenacyltriphenyl Phosphonium hydroxide, chloromethyltriphenylphosphonium hydroxide, bromomethyltriphenylphosphonium hydroxide, biphenyltriphenylphosphonium hydroxide, naphthyltriphenylphosphonium hydroxide,
Mono (aryl or alkyl) triphenylphosphonium hydroxy such as chlorophenyltriphenylphosphonium hydroxide, phenoxyphenyltriphenylphosphonium hydroxide, methoxyphenyltriphenylphosphonium hydroxide, acetoxyphenyltriphenylphosphonium hydroxide, naphthylphenyltriphenylphosphonium hydroxide Do,

Phenyltrimethylphosphonium hydroxide, biphenyltrimethylphosphonium hydroxide, phenyltrihexylphosphonium hydroxide,
Mono (aryl) trialkylphosphonium hydroxides such as biphenyltrihexylphosphonium hydroxide; diaryldialkylphosphonium hydroxides such as dimethyldiphenylphosphonium hydroxide, diethyldiphenylphosphonium hydroxide and di (biphenyl) diphenylphosphonium hydroxide; and Are tetraaryl phosphonium tetraphenyl borates such as tetraphenyl phosphonium tetraphenyl borate, tetranaphthyl phosphonium tetraphenyl borate, tetra (chlorophenyl) phosphonium tetraphenyl borate, tetra (biphenyl) phosphonium 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, octyl triphenyl phosphonium tetraphenyl borate, tetradecyl triphenyl phosphonium tetraphenyl Borate, benzyltriphenylphosphonium tetraphenylborate, ethoxybenzyltriphenylphosphonium tetraphenylborate, methoxymethyltriphenylphosphonium tetraphenylborate, acetoxymethyltriphenylphosphonium tetraphenylborate, phenacyltriphenylphosphonium tetraphenylborate, chloromethyltriborate E sulfonyl phosphonium tetraphenylborate, bromomethyltriphenylphosphonium tetraphenylborate, biphenyl triphenylphosphonium tetraphenylborate, naphthyltrimethoxysilane Li tetraphenylborate, chlorophenyl triphenylphosphonium tetraphenylborate,
Mono (aryl or alkyl) triphenylphosphonium tetraphenylborate such as phenoxyphenyltriphenylphosphonium tetraphenylborate, acetoxyphenyltriphenylphosphonium tetraphenylborate, naphthylphenyltriphenylphosphonium tetraphenylborate, phenyltrimethylphosphonium tetraphenylborate, biphenyl Monoaryl trialkyl phosphonium tetraphenyl borates such as trimethyl phosphonium tetraphenyl borate, phenyl trihexyl phosphonium tetraphenyl borate, biphenyl trihexyl phosphonium tetraphenyl borate, dimethyl diphenyl phosphonium tetraphenyl borate, diethyl diphenyl phosphonium tetraphenyl Rate, 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 instead of the above hydroxides and tetraphenylborates. The above quaternary phosphonium salts using a halogen atom such as a carbonyloxy group, chloride and bromide are mentioned.

Further, in addition to the compound represented by the general formula (XII), those having a divalent counter anion represented by the general formula (XIII), for example, bis (tetraphenylphosphonium) carbonate, bis ( Quaternary phosphonium salts such as biphenyltriphenylphosphonium) carbonate, and further, for example, bis-tetraphenylphosphonium salt of 2,2-bis (4-hydroxyphenyl) propane, ethylenebis (triphenylphosphonium) dibromide, trimethylenebis ( Triphenylphosphonium)
And bis (tetraphenyl borate).

Further, a compound represented by formula (XIV) or (XV) is also used. _{^{((R 13 -Ph) n -PPh}} (4-n)) + (X 4) - ··· (XIV) ((R 13 -Ph) n -PPh (4-n)) 2 + (Y 3) ² -... (XV) wherein R ¹³ represents an organic group, which may be the same or different, and X ⁴ represents a halogen atom, a hydroxyl group, an alkyloxy group, an aryloxy group, an alkylcarbonyloxy group , Arylcarbonyloxy group, HCO ₃ or BR
₄ (R represents a hydrogen atom or a hydrocarbon group, and four Rs may be the same or different), Ph represents a phenyl group, Y ³ represents CO ₃ , and n represents 1 to 4 Indicates an integer. ]

Specific examples of such a quaternary phosphonium compound include, for example, tetraphenylphosphonium hydroxide, biphenyltriphenylphosphonium hydroxide, methoxyphenyltriphenylphosphonium hydroxide, phenoxyphenyltriphenylphosphonium hydroxide, naphthylphenyltriphenyl Phosphonium hydroxide, tetraphenylphosphonium tetraphenylborate, biphenyltriphenylphosphonium tetraphenylborate, methoxyphenyltriphenylphosphonium tetraphenylborate, phenoxyphenyltriphenylphosphonium tetraphenylborate, naphthylphenyltriphenylphosphonium tetraphenylborate, tetraphenylphosphonium phenoxide , Biff Nyltriphenylphosphonium phenoxide, methoxyphenyltriphenylphosphonium phenoxide, phenoxyphenyltriphenylphosphonium phenoxide, naphthylphenyltriphenylphosphonium phenoxide, tetraphenylphosphonium chloride, biphenyltriphenylphosphonium chloride, methoxyphenyltriphenylphosphonium chloride, phenoxyphenyltriphenylphosphonium Chloride or naphthylphenyltriphenylphosphonium chloride. Of these quaternary phosphonium salts, tetraphenylphosphonium tetraphenylborate is preferably used in view of the balance between the catalytic effect and the quality of the obtained polycarbonate.

Specific examples of the quaternary phosphonium salt containing a branched alkyl group include isopropyltrimethylphosphonium; isopropyltriethylphosphonium; isopropyltributylphosphonium; isopropyltriphenylphosphonium; tetraisopropylphosphonium; cyclohexyltriethylphosphonium; cyclohexyltrimethylphosphonium; cyclohexyltributyl Phosphonium; cyclohexyltriphenylphosphonium; tetracyclohexylphosphonium; 1,1,1-
Triphenylmethyltrimethylphosphonium; 1,1,
1-triphenylmethyltriethylphosphonium; 1,
1,1-triphenylmethyltributylphosphonium;
1,1,1-triphenylmethyltriphenylphosphonium and the like can be mentioned.

Specific examples of X ⁴ relating to the counter anion include:
Hydroxide; borohydride; tetraphenylborate; acetate; propionate;
Chloride; hydrocarbonate and the like.

Specific examples of Y ³ include carbonate and the like. Specific examples of the salt composed of a quaternary phosphonium (cation) containing a branched alkyl group and X or Y (anion) include various combinations of the above specific examples, and isopropyltrimethylphosphonium hydroxide Cyclohexyltriphenylphosphonium chloride; 1,1,1
-Triphenylmethyltriethylphosphonium acetate; bis (isopropyltriethylphosphonium) carbonate;

Among these quaternary phosphonium salts containing a branched alkyl group, cyclohexyltriphenylphosphonium tetraphenylborate and cyclopentyltriphenylphosphonium tetraphenylborate are particularly preferred because of their excellent balance between the catalytic effect and the quality of the polycarbonate obtained. 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.

It is preferable that these quaternary phosphonium salts contain as little metal impurities as possible.
In particular, those having a content of an alkali metal or alkaline earth metal compound of 50 ppm or less are preferable.

Specific preferred prepolymerization procedures and conditions will be described. By treating the (A) dihydroxy compound and (B) carbonate diester and, if necessary, a comonomer such as a (C) terminal terminator or (D) a branching agent with heating, the aromatic monohydroxy compound is eliminated. A prepolymer can be prepared. At this time, as the polymerization catalyst, at least one selected from a nitrogen-containing organic basic compound and a phosphorus-containing basic compound is preferably used. The viscosity average molecular weight of the prepolymer produced in this prepolymerization step is preferably selected from the range of 2,000 to 20,000. This prepolymerization reaction is preferably carried out in a molten state. In this case, for example, diphenyl ether, halogenated diphenyl ether, benzophenone,
Aromatic compounds such as polyphenyl ether, dichlorobenzene, methylnaphthalene, carbon dioxide, nitrous oxide,
Gases (including supercritical state) such as nitrogen, alkanes such as chlorofluorohydrocarbons, ethane and propane, cycloalkanes such as cyclohexane, tricyclo (5,2,10) decane, cyclooctane and cyclodecane, ethylene and propylene Although a solvent inert to the reaction such as an alkene may be used, the reaction may be performed without a solvent. The use ratio (preparation ratio) of the dihydroxy compound and the carbonic acid diester varies depending on the type used, the reaction temperature, the reaction pressure, and other reaction conditions. 9-2.5 mol,
Preferably 0.95 to 2.0 mol, more preferably 0.1 to 2.0 mol.
It is used in a ratio of 98 to 1.5 mol. In the case of using a terminal stopping agent which is a monovalent hydroxy compound or a branching agent which is a polyfunctional organic compound having three or more functional groups, the former is usually 0 to 1 mol of the dihydroxy compound. 0.001 to 20 mol, preferably 0.1 to 20 mol.
0025 to 15 mol, more preferably 0.005 to 10
It is used in a molar ratio, and the latter is also usually 0.001 to 20 mol, preferably 0.0025 to 15 mol, more preferably 0.0 to 1 mol per 1 mol of the dihydroxy compound.
It is used in a ratio of 05 to 10 mol.

The amount of the catalyst is preferably 10 ^-2 to 10 ^-8 mol, more preferably 10 ^-3 to 10 ^-7 mol, per 1 mol of the hydroxy compound as the component (A). If the amount of the catalyst is less than 10 ^-8 mol, the catalytic activity in the initial ^stage of the reaction may be insufficient, and if it exceeds 10 ^-2 mol, the quality of the polycarbonate may be degraded or economically disadvantageous. Absent.

The reaction temperature, reaction pressure and reaction time vary depending on the kind and amount of the raw materials and catalyst used, the required molecular weight of the obtained prepolymer, other reaction conditions, etc., but are preferably 50 to 350 ° C., more preferably 100-320
° C, more preferably at a temperature of 150 to 280 ° C, preferably at a pressure of 1.33 x 10 Pa to 0.5 MPa (Gauge), preferably for 1 minute to 100 hours, more preferably for 2 hours.
It is selected in the range of minutes to 10 hours.

In order not to color the prepolymer, it is desirable to carry out the prepolymerization reaction at a temperature as low as possible and in a short time. As the reactor used in such a prepolymer production step, any conventionally known polymerization reactor may be used. The reaction step may be performed in one step or may be performed by dividing into more steps. In addition, one or more reactors can be used by connecting them in series or in parallel. For this production, any of a batch method, a continuous method, and a method using a combination thereof may be used.

The terminal ratio of the prepolymer produced by this step is preferably phenyl carbonate terminal: hydroxyl terminal = 100: 100 to 100: 10, more preferably 100: 60 to 100: 25. When the terminal ratio is out of the above range, the ultimate molecular weight reached is limited, and it may be difficult to increase the molecular weight in solid-state polymerization.

In this prepolymerization reaction, as the reaction proceeds, an aromatic monohydroxy compound, which is a compound in which a hydroxyl group is bonded to an aryl group based on diaryl carbonate, is produced, and this is sent out of the reaction system. Since the removal speed is increased, the effective stirring is performed, and at the same time, an inert gas such as nitrogen, argon, helium, carbon dioxide or the like, or a lower hydrocarbon gas is introduced to generate the gas. A method of removing an aromatic monohydroxy compound by accompanying these gases, a method of performing a reaction under reduced pressure, a method of using these in combination, and the like are preferably used.

(2) Heat Crystallization Step This step is a feature of the present invention. The first invention relates to a viscosity average molecular weight of 2,000 to 20,000 obtained by prepolymerization.
The heat treatment is performed on a substantially amorphous polycarbonate prepolymer having a temperature of not less than the melting temperature of the prepolymer before the heat treatment.

The second invention is to heat a substantially amorphous polycarbonate prepolymer having a viscosity-average molecular weight of 2,000 to 20,000 obtained by prepolymerization under heating conditions under which crystallization occurs from an amorphous state. To be processed.

The third invention is to prepare a substantially amorphous polycarbonate prepolymer having a viscosity average molecular weight of 2,000 to 20,000 obtained by prepolymerization from an initial stage by 19
The heat treatment is performed in the range of 5 to 230 ° C.

In the first invention, if the heat treatment is performed at a temperature lower than the melting temperature of the prepolymer before the heat treatment, crystallization takes a long time, which is not preferable. Although the melting temperature of the amorphous prepolymer can be measured by DSC, there are some prepolymers whose melting temperature is not clearly observed. In that case, the second invention and the third invention become important.

In Japanese Patent Application Laid-Open No. 1-158033, the heat treatment is carried out in a state where crystals are present from the beginning to the end, whereas in the second invention, the heat treatment is first started in a molten state (amorphous state) first. That is, heat treatment can be performed at a relatively high temperature.

In the third invention, the temperature in the initial stage is 19
If the temperature is lower than 5 ° C., crystallization takes a long time. If the temperature is higher than 230 ° C., the crystal will melt even if crystallized, and a crystallized prepolymer will not be finally obtained. Also, 195-2
In the range of 30 ° C., the heat treatment may be performed at a constant temperature or while the temperature is being increased.

The fact that the melting temperature of the prepolymer rises with the progress of the heat treatment can be said in the first to third inventions as a whole. At a certain point, this melting temperature becomes higher than the heating temperature. It is presumed that the actual crystallization starts from. At that point, the phenomena is that the prepolymer becomes opaque and the whole becomes white.

The heating crystallization treatment is not preferable in the air or the like from the viewpoint of quality such as coloring, so that it is preferable to perform the heating crystallization treatment in an atmosphere of an inert gas such as nitrogen. In the present invention, when the crystallization is performed under the above conditions, the degree of crystallinity becomes 25 to 40% within one hour, and when the crystallized prepolymer is subjected to solid-state polymerization, the molecular weight is high and the yellow index is excellent. Is obtained. Granulation into a shape suitable for the solid phase polymerization step following the heat crystallization treatment is effective in improving the operability in the subsequent step.

(3) Solid phase polymerization step In the method for producing the polycarbonate of the present invention,
After preparing the amorphous polycarbonate prepolymer, it is heated and crystallized, and the prepolymer is subjected to solid-phase polymerization to increase the molecular weight, preferably using a quaternary phosphonium salt as a polymerization catalyst. As the solid phase polymerization, there is a method of performing polymerization in a solid state and a swollen solid state.

The quaternary phosphonium salt used as the above-mentioned catalyst is the same as described above, and its amount is preferably 10 ^-2 to 10 ^-8 mol per 1 mol of the dihydroxy compound of the component (A). If the amount 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, which is not preferable.

Polymerization in Solid State The solid prepolymer in the above-mentioned heated and crystallized state is further subjected to a polymerization reaction using a quaternary phosphonium salt as a catalyst. In this step, the reaction is promoted by extracting the aromatic monohydroxy compound, diaryl carbonate or both, which are by-produced by the reaction, out of the system. To do this, nitrogen, argon, helium,
By introducing an inert gas such as carbon dioxide or a hydrocarbon gas or a poor solvent vapor, a method of removing the gas accompanying these gases, a method of performing a reaction under reduced pressure, or a method of using these in combination is preferable. Used. When introducing entraining gases, it is desirable to heat these gases to a temperature near the reaction temperature.

As the conditions of the poor solvent, the solubility of the polycarbonate in the solvent is 0.1% by mass or less under the following reaction conditions, and the straight-chain or branched-chain carbon atoms having 4 to 18 carbon atoms are less likely to be involved in the reaction. Or a unsaturated hydrocarbon compound having 4 to 18 carbon atoms and a low degree is preferred. If the boiling point exceeds 250 ° C., it becomes difficult to remove the residual solvent, and the quality may deteriorate, which is not preferable.

The shape of the crystallized prepolymer in the case of carrying out the solid-state polymerization reaction is not particularly limited, but is preferably in the form of powder, granule, pellet, bead or the like.

As a reaction catalyst in this solid-phase polymerization, a quaternary phosphonium salt and other catalysts are used, if necessary, but the remaining catalyst added in the prepolymer production step and used as it is is used as it is. Alternatively, the catalyst may be added again in a powder, liquid or gaseous state.

The reaction temperature Tp (° C.) and reaction time for carrying out the solid-state polymerization reaction are determined by the type (chemical structure, molecular weight, etc.) and shape of the crystallized prepolymer, and the presence or absence of a catalyst in the crystallized prepolymer. , The type or amount, the type or amount of the catalyst added as required, the degree of crystallization of the crystallized prepolymer or the difference in the melting temperature Tm (° C.), the required degree of polymerization of the target aromatic polycarbonate, or Although it depends on other reaction conditions and the like, it is preferably a glass transition temperature of the intended aromatic polycarbonate or higher, and a temperature in a range in which the crystallized prepolymer during the solid-state polymerization is kept in a solid state without melting, more preferably By heating at a temperature in the range represented by the following formula Tm-50 ≦ Tp <Tm for about 1 minute to 100 hours, more preferably about 0.1 to 50 hours, Phase polymerization reaction is carried out.

For example, when producing polycarbonate from bisphenol A and diphenyl carbonate, such a temperature range is preferably about 150 to 260 ° C., particularly preferably about 180 to 245 ° C.

In the polymerization step, in order to apply heat to the polymer being polymerized as uniformly as possible or to favorably remove by-products, stirring is performed, the reactor itself is rotated, or heated gas is used. Is preferably used.

In general, the viscosity average molecular weight of industrially useful polycarbonates is about 10,000 to 40,000. By carrying out the above solid phase polymerization step, a polycarbonate having such a polymerization degree can be easily obtained. Can be

Since the crystallinity of the polycarbonate obtained by the solid-state polymerization of the crystallized prepolymer is usually higher than that of the original prepolymer, the method of the present invention usually employs the crystallinity. A polycarbonate powder is obtained. Without cooling the crystalline polycarbonate powder, it can be directly introduced into an extruder and pelletized,
It can also be introduced directly into a molding machine without cooling and molded. The ratio between the pre-polymerization and the solid-phase polymerization that contribute to the polymerization may be changed in a wide range.

Polymerization in Swelled Solid State This is a method in which the prepolymer obtained in the prepolymerization step is heated and crystallized, and then further polymerized by solid state polymerization in a state swollen by a swelling gas described later. This production method is a method for producing a polycarbonate by a transesterification reaction. In the case of devolatilizing or extracting and removing a low-molecular compound such as phenol as a by-product, a polymer (prepolymer) in a swelling state by a swelling gas is used. It is an application that devolatilization or extraction and removal of low-molecular compounds have a higher mass transfer rate and higher efficiency than devolatilization or extraction and removal from high-viscosity molten polymers and crystallized solids. .

The swelling solvent used here is a single swelling solvent capable of swelling polycarbonate under the following reaction conditions:
A mixture of these single swelling solvents, or a mixture of a single swelling solvent or a mixture thereof with a poor solvent of polycarbonate as a single or several kinds of mixtures is shown. The swelling state in this step refers to a state in which the prepolymer flakes, which are the reaction raw materials, are increased volumetrically or by weight above the thermal swelling value within the range of the reaction conditions shown below,
The swelling solvent is a single compound having a boiling point of completely vaporizing under the following reaction conditions, or a single compound having a vapor pressure of usually 6.7 kPa or more, or a mixture thereof,
Simultaneously, it refers to one that can form the above-mentioned swollen state.

The swelling solvent is not particularly limited as long as it satisfies the above swelling conditions. For example, the solubility parameter usually ranges from 16 to 84 (J / cm ³ ) ^1/2 ,
Preferably, an aromatic compound or an oxygen-containing compound in the range of 30 to 60 (J / cm ³ ) ^1/2 is applicable. Specific swelling solvents include, for example, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, propylbenzene and dipropylbenzene; ethers such as tetrahydrofuran and dioxane; ketones such as methylethylketone and methylisobutylketone. Is mentioned. Among these, a single compound of an aromatic hydrocarbon having 6 to 20 carbon atoms or a mixture thereof is preferable.

The conditions of the poor solvent mixed with the swelling solvent are as follows: under the following reaction conditions, the solubility of the polycarbonate in the solvent is 0.1% by mass or less, and the linear or branched solvent is less likely to be involved in the reaction. A saturated hydrocarbon compound having 4 to 18 carbon atoms having a chain, or an unsaturated hydrocarbon compound having 4 to 18 carbon atoms and a low degree is preferred. If the boiling point of both the swelling solvent and the poor solvent exceeds 250 ° C., it becomes difficult to remove the residual solvent, and the quality may deteriorate, which is not preferable. When a mixture of such a poor solvent and a swelling solvent is used, the swelling solvent may be contained in the mixed solvent in an amount of 1% by mass or more, and preferably 5% by mass or more in the mixed solvent. To exist.

In the swelling solid phase polymerization step, the reaction is preferably carried out at a temperature of 100 to 240 ° C., at a pressure during the reaction of preferably 1.33 to 490 kPa (Gauge), particularly preferably at atmospheric pressure. If the reaction temperature is lower than the above range, the transesterification reaction does not proceed, and under the high temperature condition where the reaction temperature exceeds the melting point of the prepolymer, the solid state cannot be maintained, and phenomena such as fusion between particles occur. Properties are significantly reduced. Therefore, the reaction temperature must be lower than the melting point.

As a reaction catalyst in the swelling solid phase polymerization step, a quaternary phosphonium salt and other catalysts may be used, if necessary. Alternatively, the catalyst may be added again in a powder, liquid or gaseous state.

The swelling solvent gas may be supplied to the reactor in a liquid state and vaporized in the reactor, or may be supplied to the reactor after being vaporized by a heat exchanger or the like in advance. The flow rate of the swelling solvent gas may be 1 × 10 ⁻³ cm / s or more, and preferably 1 × 10 ⁻³ cm / s or more. Also,
As a gas supply amount, it is preferable to supply a gas of 0.5 liter (standard state) / hr or more per 1 g of the prepolymer to the reactor. The flow rate of the swelling solvent gas is closely related to the reaction rate, and acts as a heat medium simultaneously with the phenol removal effect. Therefore, the reaction rate increases as the gas flow rate increases. There is no particular limitation on the reactor used for such swelling solid-state polymerization.

For the drying and pelletizing steps of the polycarbonate having a high molecular weight, conventional methods can be used, and there is no particular limitation. When mixing the additives, it is preferable to apply the additive powder directly to the flakes before or after drying, or to spray the liquid and absorb the gas, but it is also possible to mix with an extruder during pelletization. . The mixing ratio between the inert gas and the swelling solvent may be such that the mixing solvent gas contains at least 1% by volume of the swelling solvent, and preferably 5% by volume or more of the swelling solvent is mixed with the mixed solvent. It is better to let it.

In the polycarbonate according to the present invention, well-known additives such as a plasticizer, a pigment, a lubricant, a release agent, a stabilizer, and an inorganic filler can be blended and used. This polycarbonate is made of polyolefin, polystyrene, polyester, polysulfonate,
It can be blended with polymers such as polyamide, polyphenylene ether and polyacrylate. In particular, it is effective to use in combination with polyphenylene ether, polyether nitrile, terminal-modified polysiloxane compound, modified polypropylene, modified polystyrene or the like having OH group, COOH group, NH ₂ group or the like at the terminal.

[0097]

Next, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Example 1 Bisphenol A (BPA) 228 was placed in a 1-liter autoclave made of nickel steel with a stirrer.
g (1.0 mol), diphenyl carbonate (DPC)
246 g (1.15 mol), tetramethylammonium hydroxide (TMAH) aqueous solution 0.23 ml (0.5 mmol), tetraphenylphosphonium tetraphenylborate (TPTB) 0.0066 g
(0.01 mmol), and the atmosphere was replaced with argon five times. Thereafter, the mixture was heated to 190 ° C. and reacted for 30 minutes under an argon atmosphere. Next, the temperature was gradually increased to 23.
At the same time as the temperature was raised to 5 ° C., the degree of vacuum was increased to 8.00 kPa, and the reaction was carried out for 60 minutes.
At the same time as the temperature was raised to ° C., the degree of vacuum was increased to 1.33 kPa, and the reaction was performed for 120 minutes. Next, while maintaining the temperature at 270 ° C., the degree of vacuum was increased to 0.133 kPa, and the reaction was carried out for 30 minutes.
Allowed to react for minutes. After the completion of the reaction, the inside of the reactor was returned to atmospheric pressure with argon, and the content of the prepolymer was taken out.
The viscosity average molecular weight of this prepolymer was 8,600, the terminal fraction of hydroxyl groups was 30 mol%, and the melting temperature was 156 ° C.

When the prepolymer thus obtained was put in a hot air drier kept at 200 ° C. under a nitrogen stream, the prepolymer was once melted and kept in a fluid state, and became opaque after about 10 minutes. The whole was white and crystallized. After keeping the state for a total of 45 minutes, it was pulverized to obtain a crystalline prepolymer. The crystallinity of this prepolymer is 33
%Met. 15 g of this powder is 58 mm in diameter and 17 in length.
0 mm SUS tube, nitrogen gas was flowed at a rate of 100 ml / min, and the temperature was raised from room temperature to 240 ° C.
Polycarbonate was obtained by performing solid-state polymerization for a period of time. The results are shown in Table 1.

[Examples 2 to 4] Using the prepolymer obtained in Example 1, heating crystallization and solid phase polymerization were carried out under the conditions shown in Table 1. The results are shown in Table 1.

The hydroxyl group terminal fraction of the prepolymer, the crystallinity of the prepolymer after the crystallization treatment, and the YI (yellow index) were measured in the following manner. (1) using CD ₂ Cl ₂ as hydroxyl-terminated fraction solvent, ¹ H-NMR (400
MHz, 128 times of integration), Ha and He were obtained from the obtained chart, and were calculated by the following formula. OH terminal fraction = (Ha / 2) / (Ha / 2 + He / 2) (where Ha is O of the benzene ring in the terminal phenyl group)
The integration ratio of the peaks derived from two hydrogens in the ortho position with respect to the H group is shown, and He is the integration ratio of the peaks derived from two hydrogens in the meta position with respect to the COO of the benzene ring in the terminal phenyl carbonate group. Is shown. (2) Crystallinity The endothermic enthalpy at the melting point was measured by DSC measurement, and the literature value (Polymer Letter, 8, 64) was used.
5 (1970)) and an endothermic enthalpy of 100% crystallization of 109.7 J / g. In addition, DSC
The measurement was carried out by using DSC7 manufactured by Perkin Elmer Inc. with a sample amount of 10 mg while heating at a rate of 40 ° C./min from 50 ° C. to 300 ° C. (3) A solution of 8% by mass of YI polycarbonate in methylene chloride was added to
It was taken in a 7 mm quartz cell and measured using a color meter SM-3 manufactured by Suga Test Instruments Co., Ltd.

[0101]

[Table 1]

[0102]

[Table 2]

[0103]

According to the present invention, the amorphous polycarbonate prepolymer obtained by the prepolymerization is heated at a relatively high temperature from the initial stage to carry out the crystallization treatment, whereby the crystallization time can be reduced. A production method can be provided, which is industrially extremely advantageous.

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4J029 AA09 AB05 AC01 AD01 BA05 BB04A BB04B BB05A BB06A BB10A BB10B BB12A BB12B BB12C BB13A BB13B BB16A BD03A BD04A BD07A BD09A BD09B BDB08 BF10B BD08 DB13 JC091 JC581 JC731 KF02

Claims (4)

[Claims] 1. A viscosity average molecular weight of 2,000 to 20,000.
Prior to increasing the molecular weight of the substantially amorphous polycarbonate prepolymer to a solid state, the prepolymer is subjected to heat treatment at a temperature equal to or higher than the melting temperature of the prepolymer before heat treatment to crystallize. A method for producing a polycarbonate. 2. A viscosity average molecular weight of 2,000 to 20,000.
Prior to increasing the molecular weight of the substantially amorphous polycarbonate prepolymer in the solid state to 0, the prepolymer is crystallized by heat treatment under heating conditions under which crystallization occurs from the amorphous state. Production method of polycarbonate. 3. A viscosity average molecular weight of 2,000 to 20,000.
0, prior to increasing the molecular weight of the substantially amorphous polycarbonate prepolymer in a solid state, the prepolymer is crystallized by heat treatment from an initial stage at a temperature in the range of 195 to 230 ° C. Production method of polycarbonate. 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.