WO2012005251A1

WO2012005251A1 - Continuous process for the production of branched polycarbonate

Info

Publication number: WO2012005251A1
Application number: PCT/JP2011/065384
Authority: WO
Inventors: 八谷　広志; 宗明網中
Original assignee: 旭化成ケミカルズ株式会社
Priority date: 2010-07-08
Filing date: 2011-07-05
Publication date: 2012-01-12
Also published as: JPWO2012005251A1; EA022372B1; CN102958976A; TWI492961B; EA201390078A1; JP5284540B2; MY169222A; TW201209075A; KR101458725B1; KR20130041075A; CN102958976B

Abstract

A continuous process for the production of branched polycarbonate, which includes: a step (A) of producing a low-molecular polycarbonate having a number-average molecular weight of 1000 to 10000 from an aromatic dihydroxyl compound and a carbonic diester via transesterification; a step (B) of adding the polyfunctional compound in a liquid state to the low-molecular polycarbonate, and mixing the resulting system; and a step (C) of conducting the polymerization of the mixture successively until the melt index and melt index ratio of the low-molecular polycarbonate reach 10g/10min or less and 14 or more respectively, and thus producing a branched polycarbonate.

Description

Continuous production method of branched polycarbonate

The present invention relates to a continuous production method of a branched polycarbonate by a transesterification method.

Polycarbonate is an engineering plastic with excellent mechanical strength such as transparency, heat resistance and impact strength, and is widely used in industrial applications such as optical discs, electrical and electronic fields, and automobiles. In recent years, large bottles that have been blow-molded to provide drinking water and transport mineral water in specific production areas in countries where water supply facilities are not perfect due to its design and toughness that does not easily break when dropped. Has become widespread.

In order to stably perform blow molding of such a large bottle, a higher melt viscosity and melt tension are required compared to general-purpose polycarbonate. Therefore, it is necessary to increase the melt tension of the polycarbonate by increasing the molecular weight and providing a branched structure in the molecule. In the phosgene method that has been used for a long time as a production method of polycarbonate, this problem has been solved by imparting a branched structure to the polycarbonate by using a polyfunctional compound as a branching agent as disclosed in Patent Document 1. However, since the phosgene method uses highly toxic phosgene and a large amount of chlorinated solvent, the load on the environment is large. Therefore, due to the recent increase in awareness of environmental problems, polycarbonate production methods have shifted to transesterification methods that do not use phosgene or a large amount of chlorinated solvents. However, the industrial continuous production method of the branched polycarbonate by the transesterification method is still in the development stage, and many improvement proposals have been made.

In the transesterification method, a branched polycarbonate can be produced by melt-reacting an aromatic dihydroxy compound, diphenyl carbonate and a polyfunctional compound as a branching agent in the presence of a catalyst. However, it is difficult to industrially obtain a good branched polycarbonate simply by reacting, and the following methods [1] to [3] have been proposed for the improvement.

[1] A method for reducing the Corbeschmitt-type branched structure that naturally occurs in the melting reaction process by using a specific catalyst (Patent Documents 2 to 4), or a method for improving the hue by using a specific catalyst (patents) Document 5), a method using a polyfunctional compound having a specific structure as a branching agent (Patent Documents 6 to 8).

[2] A method of obtaining a branched polycarbonate by adding a branching agent composed of a polyfunctional compound and a transesterification catalyst to the obtained polycarbonate and reacting in an extruder (Patent Documents 9 to 11).

[3] A method of producing a branched polycarbonate by actively generating a branched structure that naturally occurs in the polymerization reaction process without using a branching agent that causes process contamination (Patent Documents 12 and 13).

Japanese Patent Publication No. 47-23918 Japanese Patent Laid-Open No. 5-271400 Japanese Patent Laid-Open No. 5-271402 JP-A-5-295101 Japanese Patent Laid-Open No. 4-89824 JP 2001-302780 A Japanese translation of PCT publication No. 2002-508801 JP 2006-131910 A Japanese Patent Laid-Open No. 02-245023 JP-A-11-209469 JP 2000-290364 A JP 2002-308976 A JP 2004-002831 A

However, although the polycarbonate obtained by the production method [1] has improved hue, it has many fish eyes and is inferior in hot water resistance. In addition, since a branching agent is added together with an aromatic dihydroxy compound and diphenyl carbonate to the process of producing a linear polycarbonate, when switching from a branched polycarbonate to a linear polycarbonate, a linear chain produced later is produced. Fish eyes are generated in polycarbonate. In order to remove this adverse effect, there is a big problem that it takes a lot of time to change the brand, or it is necessary to stop production and clean the production equipment.

In addition, in the production method [2], the branching agent is not added to the polymerization step, so the above problem at the time of switching the brand is solved. However, the obtained branched polycarbonate has a lot of fish eyes and a decrease in hot water resistance is also observed. There is a problem that high-quality polycarbonate cannot be stably produced.

Furthermore, although the production method [3] has the advantage of not adding a branching agent, it is difficult to stably produce a rearrangement reaction, which is a side reaction, and even unnecessary side reactions. Occurs, causing problems such as deterioration of hue, fish eye, and a decrease in hot water resistance, and there is also a problem of loss at the time of brand switching.

The present invention has been made in view of the above circumstances, and can reduce loss at the time of brand switching, and is excellent in hue and hot water resistance, and produces a branched polycarbonate with less fish eyes by a transesterification method. It aims at providing the continuous manufacturing method of a polycarbonate.

The present invention includes (A) a step of producing a low molecular weight polycarbonate having a number average molecular weight of 1000 to 10,000 by an ester exchange method from an aromatic dihydroxy compound and a carbonic acid diester; and (B) a liquid containing a polyfunctional compound in the low molecular weight polycarbonate. A branched polycarbonate comprising: a step of adding and mixing in a state; and (C) a step of continuously producing a branched polycarbonate by performing a polymerization reaction until the melt index of the low molecular weight polycarbonate is 10 g / 10 min or less and the branching index is 14 or more. A continuous manufacturing method is provided. According to this method, it is possible to reduce a loss at the time of brand switching, and it is possible to continuously produce a branched polycarbonate excellent in hue and hot water resistance and having little fish eye by a transesterification method.

In the present invention, the range of ΔT (° C.) defined by the following formula (I) is preferably −20 ° C. to 20 ° C. or less. Thereby, the said effect of this invention is further show | played.
ΔT = T ₂ −T ₁ (I)
[Wherein T ₁ represents the temperature (° C.) of the low molecular weight polycarbonate introduced into the final polymerization vessel in the step (C), and T ₂ represents a branched polycarbonate polymerized by the final polymerization vessel in the step (C). The T ₂ is 285 ° C. or lower. ]

It is preferable that the polyfunctional compound is added to a melt mixer installed in the middle of the pipe between the device for performing the step (A) and the device for performing the step (C) in a state dissolved in a solvent. Thereby, the said effect of this invention is further show | played.

The solvent is at least selected from the group consisting of phenols, carbonic acid diesters, ketones, ethers, mixtures and reactants of aromatic dihydroxy compounds and carbonic acid diesters, and low molecular weight polycarbonates having a number average molecular weight of 5000 or less. One type is preferable. Thereby, the said effect of this invention is further show | played.

The solvent is preferably a depolymerization solvent. Thereby, the said effect of this invention is further show | played. In the present specification, the “depolymerization solvent” refers to a solvent that causes depolymerization of polycarbonate.

Further, the present invention can further include (D) a step of producing a polycarbonate by performing a polymerization reaction until the melt index becomes 100 g / 10 min or less, following the step (A). According to this production method, loss at the time of brand switching can be reduced, and a plurality of types of polycarbonates including branched polycarbonates having excellent hue and hot water resistance and few fish eyes can be produced continuously by a transesterification method. Can do.

Here, the apparatus that performs the process (A) performs the process (C) via a pipe having a branch portion that branches to lead to the apparatus that performs the process (C) and the apparatus that performs the process (D). It is connected with the apparatus and the apparatus which performs (D) process, The said polyfunctional compound may be added to the melt mixer installed in the middle of the piping between a branch part and the apparatus which performs (C) process. it can. Thereby, the said effect of this invention is further show | played.

The present invention also provides a branched polycarbonate produced by the above method. This branched polycarbonate is excellent in hue and hot water resistance and has less fish eyes.

According to the present invention, it is possible to provide a continuous production method of a branched polycarbonate, which can reduce a loss at the time of brand switching, and produce a branched polycarbonate having excellent hue and hot water resistance and less fish eye by a transesterification method. Can do.

It is the schematic of the manufacturing system which manufactures the branched polycarbonate of one Embodiment of this invention. It is the schematic of the manufacturing system which manufactures the multiple types of polycarbonate of one Embodiment of this invention.

Hereinafter, the present invention will be described in detail. In the continuous production method of a branched polycarbonate according to this embodiment, a branched polycarbonate can be produced from an aromatic dihydroxy compound, a carbonic acid diester, and a polyfunctional compound by a transesterification method.

In the present embodiment, the aromatic dihydroxy compound is, for example, a compound represented by HO—Ar—OH. Ar is a divalent aromatic residue, for example, a divalent aromatic residue represented by phenylene, naphthylene, biphenylene, pyridylene, or —Ar ¹ —Y—Ar ² —. Here, Ar ¹ and Ar ² each independently represent a divalent carbocyclic or heterocyclic aromatic group having 5 to 70 carbon atoms, and Y represents a divalent alkylene having 1 to 30 carbon atoms. Indicates a group.

In the divalent aromatic group (Ar ¹ , Ar ² ), one or more hydrogen atoms bonded to the aromatic ring are other substituents that do not adversely influence the reaction, for example, an alkyl group having 1 to 10 carbon atoms Substituted with a cycloalkyl group having 5 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, a nitro group, etc. May be. Preferable specific examples of the heterocyclic aromatic group include heterocyclic aromatic groups having one or more nitrogen atoms, oxygen atoms or sulfur atoms constituting the ring.
Ar ¹ and Ar ² are each preferably substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted pyridylene, and the like.

The divalent alkylene group Y is, for example, an organic group represented by the following general formula.

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or 5 to 5 carbon atoms constituting the ring) 10 represents a cycloalkyl group, a carbocyclic aromatic group having 5 to 10 carbon atoms constituting the ring, or a carbocyclic aralkyl group having 6 to 10 carbon atoms, k represents an integer of 3 to 11; R ⁵ and R ⁶ are individually selected for each X and independently of each other represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, X represents carbon, and R ¹ , R ² , R ³ , In R ⁴ , R ⁵ , and R ⁶ , one or more hydrogen atoms may be other substituents, for example, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, within a range that does not adversely affect the reaction, Phenyl group, phenoxy group, vinyl group, cyano group, ester group, amide group, nitrite It may be substituted by a group.)

Examples of the divalent aromatic residue Ar having a substituent as described above include those represented by the following general formula.

(Wherein R ⁷ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms constituting the ring, or M and n each represent an integer of 1 to 4, and when m is 2 to 4, each R ⁷ may be the same or different. When n is 2 to 4, each R ⁸ is Each may be the same or different.)

Further, the divalent aromatic residue Ar may be represented by —Ar ¹ —Z—Ar ² —. Ar ¹ and Ar ² are as described above, and Z is a single bond or —O—, —CO—, —S—, —SO ₂ —, —SO—, —COO—, —CON (R ¹ ) —, etc. Represents a divalent group. However, R ¹ is as described above.

As such a bivalent aromatic residue Ar, what is represented by the following general formula is mentioned, for example.

(Wherein R ⁷ , R ⁸ , m and n are as described above.)

The aromatic dihydroxy compound used in this embodiment may be used alone or in combination of two or more. A typical example of the aromatic dihydroxy compound is bisphenol A. When used together with other aromatic dihydroxy compounds, bisphenol A is used in a proportion of 85 mol% or more based on the total amount of the aromatic dihydroxy compounds. It is preferable to use it. These aromatic dihydroxy compounds preferably have a low content of chlorine atoms and alkali or alkaline earth metal, and are preferably not substantially contained if possible.

The carbonic acid diester used in the present embodiment is, for example, a compound represented by the following general formula.

(In the formula, Ar ³ and Ar ⁴ each represent a monovalent aromatic group.)

The monovalent aromatic groups Ar ³ and Ar ⁴ are preferably a phenyl group, a naphthyl group, a biphenyl group, and a pyridyl group. In Ar ³ and Ar ⁴ , one or more hydrogen atoms bonded to the aromatic ring are other substituents that do not adversely influence the reaction, for example, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms , Phenyl group, phenoxy group, vinyl group, cyano group, ester group, amide group, nitro group and the like. Ar ³ and Ar ⁴ may be the same as or different from each other.

More preferable examples of Ar ³ and Ar ⁴ include groups represented by the following formulas.

Representative examples of carbonic acid diesters include substituted or unsubstituted diphenyl carbonates represented by the following general formula.

(Wherein R ⁹ and R ¹⁰ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms constituting the ring, or Represents a phenyl group, p and q represent an integer of 1 to 5, each R ⁹ may be different when p is 2 or more, and each R ¹⁰ may be different when q is 2 or more. .)

Among the carbonic acid diesters, symmetric diaryl carbonates such as unsubstituted diphenyl carbonate and lower alkyl-substituted diphenyl carbonates such as ditolyl carbonate and di-t-butylphenyl carbonate are preferable, and diphenyl carbonate is more preferable. These carbonic acid diesters may be used alone or in combination of two or more. In addition, these carbonic acid diesters preferably have a low content of chlorine atoms and alkali or alkaline earth metals, and preferably do not substantially contain them.

The use ratio (feed ratio) of the aromatic dihydroxy compound and the carbonic acid diester varies depending on the kind of the aromatic dihydroxy compound and the carbonic acid diester used, the target molecular weight, the hydroxyl group terminal ratio, the polymerization conditions, etc., and is not particularly limited. The carbonic acid diester is preferably 0.9 to 2.5 mol, more preferably 0.95 to 2.0 mol, still more preferably 0.98 to 1.5 mol with respect to 1 mol of the aromatic dihydroxy compound. Used. An aromatic monohydroxy compound may be used in combination for terminal conversion and molecular weight adjustment.

The polyfunctional compound used in the present embodiment is a compound having three or more functional groups reactive to the carbonic acid diester in the molecule, and having three or more phenolic hydroxyl groups and / or carboxyl groups. Is preferred. Examples of the polyfunctional compound include 1,1,1-tris (4-hydroxyphenyl) ethane, 4- [4- [1,1-bis (4-hydroxyphenyl) ethyl] -α, α-dimethylbenzyl]. Phenol, 2,2 ′, 2 ″ -tris (4-hydroxyphenyl) diisopropylbenzene, α, α ′, α ″ -tris (4-hydroxyphenyl) triisopropylbenzene, phloroglysin, 4,6-dimethyl-2, 4,6-tri (4-hydroxyphenyl) heptane-2,1,3,5-tri (4-hydroxyphenyl) benzol, 2,2′-bis- [4,4- (4,4′-dihydroxydiphenyl) ) Cyclohexyl] propane, α-methyl-α, α ′, α′-tris (4-hydroxyphenyl) -1,4-diethylbenzene, tri- (4-hydroxyphenyl) phenyl Nylmethane, 2,4-bis (4-hydroxyphenylisopropyl) phenol, 2,6-bis (2-hydroxy-5′-methylbenzyl) -4-methylphenol, 2- (4-hydroxyphenyl) -2- ( 2,4-dihydroxyphenyl) propane, hexa- (4- (4-hydroxyphenylisopropyl) phenyl) terephthalic acid ester, tetra- (4-hydroxyphenyl) methane, tetra- (4- (4-hydroxyphenylisopropyl) phenoxy ) Methane, 1,4-bis (4 ′, 4 ″ -dihydroxy-triphenyl) methylbenzene, 2,4-dihydroxybenzoic acid, trimesic acid, 3,3-bis (3-methyl-4-hydroxyphenyl) -2-Oxo-2,3-dihydroindole, trimesic acid trichloride, α, α ', α'' Tris (4-hydroxyphenol) -1,3,5-triisopropylbenzene, trimellitic acid, 1,3,5-benzenetricarboxylic acid, pyromellitic _{_{acid, C 6 H 5 -Si- (O}} -Si (CH 3 ) ₂ -C ₃ H ₆ -C ₆ H ₄ -OH) ₃ , CH ₃ -Si- (O-Si (CH ₃ ) ₂ -C ₃ H ₆ -C ₆ H ₄ -OH) ₃ Most preferred are 1,1,1-tris (4-hydroxyphenyl) ethane and 4- [4- [1,1-bis (4-hydroxyphenyl) ethyl] -α, α-dimethylbenzyl] phenol.

The amount of the polyfunctional compound used is preferably from 0.1 to 0.95 mol%, more preferably from 0.2 to 0.8 mol%, particularly preferably from 0.1 to 0.9 mol% based on the aromatic dihydroxy compound. 3 to 0.6 mol%. When the amount of the polyfunctional compound used is 0.95 mol% or less, it is difficult for fish eyes to increase, and when it is 0.1 mol% or more, the melt tension can be increased.

The transesterification method is a method in which the above compound is polycondensed in a transesterification reaction in a molten state with heating in the presence or absence of a catalyst, under reduced pressure and / or inert gas flow, and the polymerization. There are no restrictions on the method, apparatus, etc. Examples of the apparatus include a stirred tank reactor, a thin film reactor, a centrifugal thin film evaporation reactor, a surface renewal type biaxial kneading reactor, a biaxial horizontal stirring reactor, a wet wall reactor, and a polymerization while allowing it to fall freely. For example, a perforated plate reactor, a perforated plate reactor with wire that is polymerized while being dropped along the wire, and the like are used. In this embodiment, by combining these, the polycondensation reaction can be advanced stepwise to produce the target polycarbonate. For example, a molten prepolymer having a low molecular weight is produced in a stirred tank reactor, and the obtained molten prepolymer is polymerized while being dropped along a perforated plate reactor and a wire that are polymerized while freely dropping. It is preferred to further polymerize using a wire contact flow polymerizer. In particular, for the polymerization vessel installed after the melt mixer, it is preferable to use a wire contact flow type polymerization vessel excellent in substitution efficiency with little loss after switching. For these production methods, reference can be made, for example, to US Pat. No. 5,589,564. The material of these reactors is not particularly limited, but the material constituting at least the inner wall surface of the reactor is usually selected from stainless steel, nickel, glass and the like.

The temperature at which the melt polycondensation is carried out in the transesterification reaction is preferably 50 to 320 ° C. As the reaction proceeds, an aromatic monohydroxy compound is produced, and the reaction rate can be increased by removing this from the reaction system. Therefore, nitrogen, argon, helium, carbon dioxide, lower hydrocarbon gas, and other inert gases that do not adversely affect the reaction are introduced, and the resulting aromatic monohydroxy compounds are removed by accompanying these gases. And a method of reacting under reduced pressure are preferably used. The preferred reaction pressure varies depending on the molecular weight of the product, and is preferably 10 mmHg to normal pressure in the early stage of polymerization, preferably 20 mmHg or less, particularly preferably 10 mmHg or less, and particularly preferably 5 mmHg or less in the final polymerization vessel.

Hereinafter, the (A) process, (B) process, and (C) process of this embodiment will be described. Although it demonstrates in detail using FIG. 1, the manufacturing method of this embodiment is not limited to this.

The continuous production method of the branched polycarbonate of the present embodiment includes (A) a step of producing a low molecular weight polycarbonate having a number average molecular weight of 1000 to 10,000 by an ester exchange method from an aromatic dihydroxy compound and a carbonic acid diester, and (B) a low molecular weight. It comprises a step of adding and mixing a polyfunctional compound in a polycarbonate in a liquid state, and (C) a step of performing a polymerization reaction until the melt index (MI) of the low molecular weight polycarbonate is 10 g / 10 min or less and the MIR is 14 or more.

The branched polycarbonate production system shown in FIG. 1 includes a first stirring polymerization step having stirring tank type

first polymerization units

3A and 3B, a second stirring polymerization step having stirring tank type second polymerization unit 3C, and a stirring tank type. A third agitation polymerization step having a third polymerization vessel 3D, a first wire contact flow-down polymerization step having a wire contact flow-down type first polymerization vessel 108A, and a first having a wire contact flow-down second polymerization vessel 108B. It consists of a two-wire contact flow polymerization process.

(A) The process is a process from 3A and 3B to 3C, 3D, and 108A.

Stirrer tank type polymerizers 3A to 3D respectively include polymerization

raw material inlets

1A and 1B or

prepolymer inlets

1C and 1D, vent ports 2A to 2D, outlets 5A to 5D, and stirrers 6A to 6A having anchor type stirring blades. 6D is provided. An aromatic dihydroxy compound and a carbonic acid diester among the polymerization raw materials are charged into the stirring tank type

first polymerization devices

3A and 3B installed in parallel, and the first stirring polymerization process is performed in a batch manner. In general, a polymerization catalyst is added at this stage, but it may be added in a subsequent process. The produced melted

prepolymers

4A and 4B are introduced from the prepolymer inlet 1C into the stirring tank type second polymerization vessel 3C through a transfer pipe. At this time, you may use the transfer pump 8 installed in the middle of the transfer path as needed for the transfer of the melted

prepolymers

4A and 4B. Further, the molten prepolymer 4C which has been polymerized in the second stirring polymerization step is pushed out by a transfer pump 7C provided at the outlet 5C of the stirring tank type second polymerization device 3C, and is stirred through the transfer pipe. 3D is charged from the prepolymer inlet 1D. Thus, the second and third stirred polymerization steps are performed continuously.

The molten prepolymer 4D generated in the third stirring polymerization step is pushed out from the outlet 5D of the stirring tank type third polymerization vessel 3D by the transfer pump 7D and transferred to the wire contact flow type first polymerization vessel 108A through the transfer pipe. The

Next, the first and second wire contact flow type polymerization processes are continuously performed in the wire contact flow type first and

second polymerization reactors

108A and 108B. The first and

second polymerization reactors

108A and 108B, respectively, are provided with

prepolymer inlets

101A and 101B,

perforated plates

102A and 102B, wire guides 103A and 103B,

gas supply ports

104A and 104B, vent

ports

105A, 105B and

outlets

107A and 107B are provided.

Polymerization proceeds while the molten prepolymer 4D charged from the prepolymer inlet 101A flows in contact with the wire, and the molten prepolymer 109A accumulates in the lower part of the wire contact flow type first polymerization vessel 108A. Here, the polymerization reaction proceeds until the number average molecular weight (Mn) of the molten prepolymer 109A becomes 1000 to 10,000. The number average molecular weight is preferably 1500 to 8000, more preferably 2000 to 7000. When Mn is 1000 or more, loss at the time of brand switching can be reduced, and when it is 10000 or less, fish eyes tend to be reduced and a decrease in hot water resistance tends to be suppressed. The molten prepolymer 109A is pushed out from the outlet 107A by the transfer pump 106A, and transferred to the prepolymer inlet 101B of the wire contact flow type second polymerization vessel 108B through the transfer pipe. In this embodiment, the number average molecular weight and the weight average molecular weight can be measured using gel permeation chromatography (GPC).

Step (B) is a step of adding and mixing a polyfunctional compound in a liquid state to the low molecular weight polycarbonate obtained in step (A). In FIG. 1, a transfer pipe from the outlet 107 </ b> A to the prepolymer inlet 101 </ b> B, a melt mixer (line mixer) 110 installed in the middle of the transfer pipe, and a polyfunctional compound input pipe 111 correspond. In this case, the polyfunctional compound is in a liquid state, charged into the melt mixer 110 via the polyfunctional compound charging pipe 111, and mixed with the molten prepolymer 109A transferred from the wire contact flow type first polymerization vessel 108A. The Here, when the depolymerization reaction occurs, the depolymerization reaction may be completed until equilibrium is reached in the melt mixer, or may be completed in a subsequent transfer pipe. Moreover, since there exists process (C) after this, it is not necessary to make it react until depolymerization reaches an equilibrium completely by this process. In order to make the mixing more uniform, a mixing region such as a static mixer can be installed in the transfer pipe.

(B) The process may be in the middle of the outlet 5D and the prepolymer inlet 101A in the system of FIG. 1, for example, or in the middle of the piping between the outlet 5C and the prepolymer inlet 1D. In the step (B) of the present embodiment, the polyfunctional compound is added directly to the transfer pipe without using a melt mixer, and the reaction (solution) is performed by installing a mixing region in the transfer pipe or a static mixer. If a polymerization reaction takes place, the depolymerization reaction may also proceed. Moreover, a kneading apparatus such as a twin screw extruder can be used as the melt mixer. In that case, the polyfunctional compound may be added in a molten state, or in the case of powder, it may be added in a state dissolved in a solvent. In order to reduce fish eyes and improve hot water resistance, the polyfunctional compound is preferably added in a molten state or dissolved in a solvent, and particularly preferably added in a state dissolved in a solvent.

In the present embodiment, the polyfunctional compound can be added to the melt mixer in a state of being dissolved in a solvent. Solvents that dissolve the polyfunctional compound include phenols, aromatic dihydroxy compounds, carbonic acid diesters, ketones, ethers, mixtures and reactants of aromatic dihydroxy compounds and carbonic acid diesters, and low number average molecular weights of 5000 or less. A compound such as a molecular weight polycarbonate is preferably present in the plant. These solvents may be used alone or in combination of two or more. When these compounds are used as a solvent, the fish eyes of the resulting branched polycarbonate are reduced. The reason is not clear, but when these compounds are used as a solvent, depolymerization of the polycarbonate is caused, so that it is presumed that the dispersion of the polyfunctional compound further proceeds. In this case, the molecular weight of the polycarbonate is once reduced by depolymerization, and if the amount of reduction is too large, it is not preferable for production. Therefore, the amount of solvent is adjusted so that the ratio of molecular weight reduction is less than 50%, more preferably less than 30%. Is preferably determined. Moreover, as a solvent which melt | dissolves a polyfunctional compound, it can also add in the state dissolved in general purpose solvents, such as methanol, ethanol, acetone, a methylene chloride.

In the present embodiment, “the polyfunctional compound in a liquid state” means a state where the polyfunctional compound itself is in a molten state and a state where the polyfunctional compound is dissolved in a solvent as described above. Therefore, the temperature at which the polyfunctional compound is in a liquid state can be selected arbitrarily depending on the solvent used.

In the present embodiment, “the polyfunctional compound in a liquid state” may be a state in which the polyfunctional compound is dissolved by reacting with a solvent and / or other components. Here, the other component may be a catalyst that promotes the reaction between the polyfunctional compound and the solvent. Any catalyst can be selected depending on the solvent, and the catalyst used in the polymerization can also be used.

Step (C) is a step for continuing the polymerization reaction of the low molecular weight polycarbonate so that the MI of the polycarbonate is 10 g / 10 min or less and the branching index MIR is 14 or more. In FIG. 1, it corresponds to the wire contact flow type second polymerization vessel 108B. (C) The number of polymerization vessels in step (C) is not particularly limited. However, if the number of polymerization vessels is large, there is a risk that switching time and loss will increase in brand switching, so it is preferable that there is only one polymerization vessel. .

The molten prepolymer 109A charged into the wire contact flow-down type second polymerization vessel 108B, like the wire contact flow-down type first polymerization vessel 108A, is in contact with the wire and polymerization proceeds while flowing down. It accumulates in the lower part in the wire polymerization flow-down type second polymerization vessel 108B. The molten polymer 109B is discharged from the outlet 107B by the discharge pump 106B and recovered as a branched polycarbonate.

The melted prepolymer 109A charged into the wire contact flow type second polymerization vessel 108B depends on the temperature of the polymerization tank, but the higher the amount of the prepolymer supplied, the more polymerized the more high molecular weight polymer is produced. It will be necessary to get time. Therefore, the productivity of high molecular weight polymers is reduced. Also, when the supply of prepolymer is small, quality issues arise as issues other than productivity. If the supply amount is too slow, a part of the prepolymer remaining on the wire may stay and cause fish eyes to increase.

In the conventional method, when MI <5, the productivity tends to decrease, and when MI <4, there is a concern that the fish eye increases in addition to the decrease in productivity.

In the method of the present embodiment, the productivity can be increased and the quality can be improved by supplying a specific amount of prepolymer per wire. In the conventional method, in order to produce a high molecular weight polymer, a supply amount of the prepolymer to the wire contact flow type second polymerization vessel 108B is limited. On the other hand, in the method of the present embodiment, by introducing a prepolymer containing a branching agent, it is possible to obtain an unpredictable effect that the retention on the wire when the wire is dropped increases.

Specifically, the supply amount of the prepolymer to the wire polymerization flow-down type second polymerization vessel 108B which is the final polymerization device is, when an 8 m wire is used, one wire, the amount (kg) per unit time (hour) Is preferably 0.3 to 3.0 kg / (hr · book), more preferably 0.4 to 2.5 kg / (hr · book), and further 0.5 to 2.0 kg / (hr · book). preferable. In addition, the supply amount of the prepolymer to the wire is proportional to the length of the wire.

When the supply amount is less than 0.3 kg / (hr · book), the productivity is deteriorated, and the influence on the product (increased fish eye, etc.) may occur due to the residence of some polymers in the wire. On the other hand, when the supply amount exceeds 3.0 kg / (hr · book), the residence time becomes short and the wire contact time of the prepolymer becomes short, and it becomes difficult to obtain a sufficient molecular weight.

In this embodiment, from the viewpoint of obtaining sufficient MI and MIR, and improving the hue and the number of fish eyes, the reaction temperature through the steps (A) to (C) is preferably 50 to 320 ° C., 100 to 300 ° C is more preferable, 130 to 280 ° C is more preferable, and 150 to 270 ° C is particularly preferable. Of these, the step (C) is preferably 250 to 320 ° C, more preferably 250 to 300 ° C, still more preferably 255 to 280 ° C, and particularly preferably 260 to 270 ° C.

In the present embodiment, the range of ΔT (° C.) defined by the following formula (I) is −20 ° C. to 20 ° C. from the viewpoint of impact strength, hue, and gel generation of the obtained branched polymer. preferable.
ΔT = T ₂ −T ₁ (I)
Here, T ₁ indicates the temperature (° C.) of the low molecular weight polycarbonate introduced into the final polymerization vessel in the step (C), and T ₂ indicates the temperature (° C.) of the branched polycarbonate polymerized by the final polymerization vessel in the step (C). ) And T ₂ is 285 ° C. or lower.

T ₂ is preferably 250 ° C. to 285 ° C., more preferably 260 ° C. to 275 ° C. The “final polymerization vessel” refers to a polymerization vessel that performs the reaction until the MI of the branched polycarbonate becomes 10 g / 10 min or less.

In a general melt polymerization method, the viscosity of the polymer increases as the molecular weight increases in the final polymerization reactor corresponding to step (C) of this embodiment. There is. In the method of the present embodiment, by using a vertical polymerization vessel as the final polymerization vessel, it becomes possible to obtain a branched polycarbonate having extremely high physical properties and quality while having a high viscosity that could not be obtained so far. .

In this embodiment, MI is measured by the method of ASTM D1238 at a temperature of 300 ° C. and a load of 1.2 kg. Similarly, the branching index MIR is obtained by dividing the value measured at 12 kg load by the MI value. In this embodiment, the branched polycarbonate obtained in the step (C) has an MI of 10 g / 10 min or less, preferably 0.5 to 8 g / 10 min, more preferably 1 to 6 g / 10 min, and particularly a large size such as a 5 gallon bottle. When used in a bottle, 2 to 4 g / 10 min is preferable. When it is smaller than this range, the moldability tends to decrease, and when it is larger than 10 g / 10 min, the moldability tends to decrease. The branching index MIR is 14 or more, preferably 15 to 30, more preferably 16 to 25. If it is smaller than 14, improvement in blow moldability is not sufficient, and molding defects and uneven thickness are likely to occur, and if it is larger than 30, molding defects and uneven thickness tend to occur and fish eyes tend to increase. is there.

After the step (C), the obtained branched polycarbonate is usually pelletized, but it may be directly connected to a molding machine to produce a molded product such as a sheet or a bottle. Further, a polymer filter or the like having a filtration accuracy of about 1 to 50 μm may be installed in order to refine or remove the fish eye.

In this embodiment, as another embodiment, a process (D) for producing a polycarbonate by performing a polymerization reaction until the melt index becomes 100 g / 10 min or less can be provided following the process (A). According to such an embodiment, a plurality of types of polycarbonates can be produced. Hereinafter, the aspect provided with (D) process is demonstrated, referring FIG.

FIG. 2 is a schematic view of a production system for producing a plurality of types of polycarbonate. The production system includes a first stirring polymerization step having stirring tank type

first polymerization devices

3A and 3B, a second stirring polymerization step having stirring tank type second polymerization device 3C, and a stirring tank type third polymerization device 3D. , A first wire contact flow-down polymerization process having a wire contact flow-down type first polymerization vessel 108A, and a second wire contact flow-down polymerization method having a wire contact flow-down second polymerization device 108B. The point provided with a process is the same as that of the system shown in FIG. In the method for producing a plurality of types of polycarbonates of the present embodiment, in addition to these, a third wire contact flow-down polymerization process having a wire contact flow-down third polymerizer 108C, transfer pumps 106A and 106D, and a branching unit 120 are provided. Prepare.

(A) The molten prepolymer 109A produced in the step (A) is discharged from the outlet 107A and enters the transfer pipe. This transfer pipe has a branching portion 120 branched so as to lead to the device for performing the step (B) and the device for performing the step (D). The molten prepolymer 109A that has flowed out from the outlet 107A is branched at the branching portion 120, and at each branched downstream, at the transfer pump 106D that is the inlet of the step (B) and / or at the inlet of the step (D). It is pushed out by a certain transfer pump 106A and transferred through a transfer pipe to the prepolymer inlet 101B of the wire contact flow down second polymerizer 108B and / or the prepolymer inlet 101C of the wire contact flow down third polymerizer 108C. .

When the transfer pump 106D is operating, a branched polycarbonate is produced by the steps (A), (B), and (C) as in the above-described embodiment. Here, the transfer piping from the transfer pumps 106D to 101B in FIG. 2, the melt mixer (line mixer) 110 installed in the transfer piping, and the polyfunctional compound input piping 111 correspond to the step (B). The wire contact flow type second polymerization vessel 108B to the outlet 107B correspond to the step (C).

When the transfer pump 106A is operating, the first and third wire contact flow type polymerization processes are continuously performed in the wire contact flow type first and

third polymerization reactors

108A and 108C.

Step (D) corresponds to the process from the transfer pump 106A to the outlet 107C through the wire contact flow type third polymerization vessel 108C. In the step (D), the molten prepolymer 109A transferred through the transfer pipe from the outlet 107A of the wire contact flow type first polymerization vessel 108A by the operation of the transfer pump 106A is converted into the prepolymer of the wire contact flow type third polymerization device 108C. It is transferred to the polymer inlet 101C.

The molten prepolymer 109A charged into the wire contact flow-down type third polymerization vessel 108C, like the wire contact flow-down type first polymerization vessel 108A, is brought into contact with the wire and polymerization proceeds while flowing down. , Accumulated in the lower part of the wire contact flow type third polymerization vessel 108C. The molten polymer 109C is discharged from the outlet 107C by the discharge pump 106C and recovered as polycarbonate.

The polycarbonate obtained in step (D) has an MI of 100 g / 10 min or less, preferably 1 to 90 g / 10 min, more preferably 5 to 80 g / 10 min, and is determined by the brand to be produced. When the MI is within the above range, the mechanical properties and moldability are excellent.

In the production system shown in FIG. 2, a branched polycarbonate is produced in the step (B) and the subsequent (C) step having a melt mixer 110 for introducing a polyfunctional compound, and the polycarbonate is produced in the step (D). it can. By adjusting the operating conditions of the transfer pumps 106A and 106D, it is possible to adjust the amount of the branched polycarbonate produced in the step (B) and the step (C) and the amount of the polycarbonate produced in the step (D). Further, if any one of the transfer pumps 106A and 106D is stopped, only the desired polycarbonate produced in the step (B) and the step (C) or the step (D) can be obtained. In this way, the present embodiment can extremely reduce the loss of brand switching. In FIG. 2, one (A) process includes one (B) process, one (C) process, and one (D) process, but there may be a plurality of each.

In the present embodiment, from the viewpoint of obtaining sufficient MI and MIR, and improving the number of hues and fish eyes, the steps (A), (B), (C) and (D) In any case, the reaction temperature is preferably 50 to 320 ° C, more preferably 100 to 300 ° C, further preferably 130 to 280 ° C, and particularly preferably 150 to 270 ° C. Among these, the steps (C) and (D) are preferably in the range of 250 to 320 ° C, more preferably 250 to 300 ° C, still more preferably 255 to 280 ° C, and particularly preferably 260 to 270 ° C.

In the method of this embodiment, when manufacturing a branched polycarbonate composition containing additives such as stabilizers, antioxidants, dyes and pigments, ultraviolet absorbers, flame retardants, reinforcing agents with glass fibers and fillers, etc. The branched polycarbonate is supplied to the extruder, static mixer, etc. in the molten state from the final reactor in the steps (C) and (D), and the above additives are added, melt kneaded and pelletized. Is preferred.

In the method of this embodiment, a polymerization catalyst can be used so that it may be added at the process of the said Example (A). The polymerization catalyst to be used is not particularly limited as long as it is used in this field, but water of alkali metal or alkaline earth metal such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, etc. Oxides: lithium aluminum hydride, sodium borohydride, alkali metal salts, alkaline earth metal salts, quaternary ammonium salts of boron and aluminum hydrides such as tetramethylammonium borohydride; lithium hydride, hydrogen Alkali metal or alkaline earth metal hydrides such as sodium hydride and calcium hydride; Alkali metal or alkaline earth metal alkoxides such as lithium methoxide, sodium ethoxide and calcium methoxide; lithium phenoxide, sodium phenoxide, Magnesium phenoxy Alyloxides of alkali metals or alkaline earth metals such as LiO—Ar—OLi, NaO—Ar—ONa (where Ar is an aryl group); Alkali metals or alkaline earths such as lithium acetate, calcium acetate, sodium benzoate Metal organic acid salts; zinc compounds such as zinc oxide, zinc acetate, zinc phenoxide; boron oxide, boric acid, sodium borate, trimethyl borate, tributyl borate, triphenyl borate, (R ¹ R ² R ³ Ammonium borates represented by R ⁴ ) NB (R ¹ R ² R ³ R ⁴ ), phosphonium borates represented by (R ¹ R ² R ³ R ⁴ ) PB (R ¹ R ² R ³ R ⁴ ) ^{^{^{(wherein, R 1, R 2, R}}} 3, R 4 each independently represent a hydrogen atom, an alkyl group, an alkoxy group having 1 to 10 carbon atoms having 1 to 10 carbon atoms, the ring A cycloalkyl group having 5 to 10 carbon atoms, a carbocyclic aromatic group having 5 to 10 carbon atoms constituting a ring, or a carbocyclic aralkyl group having 6 to 10 carbon atoms). Compounds of boron; silicon compounds such as silicon oxide, sodium silicate, tetraalkyl silicon, tetraaryl silicon, diphenyl-ethyl-ethoxy silicon; germanium such as germanium oxide, germanium tetrachloride, germanium ethoxide, germanium phenoxide Compounds; tin compounds such as tin oxides, organotin compounds, tin compounds bonded to alkoxy groups or aryloxy groups such as tin oxide, dialkyltin oxide, dialkyltin carboxylate, tin acetate, ethyltin tributoxide; lead oxide, lead acetate , Lead carbonate, basic carbonate, lead and organic lead alkoxide or Is a lead compound such as aryloxide; onium compounds such as quaternary ammonium salts, quaternary phosphonium salts and quaternary arsonium salts; antimony compounds such as antimony oxide and antimony acetate; manganese acetate, manganese carbonate, and boron Manganese compounds such as manganese acid; Titanium compounds such as titanium oxide, titanium alkoxide or aryloxide; Catalysts such as zirconium compounds such as zirconium acetate, zirconium oxide, zirconium alkoxide or aryloxide, zirconium acetylacetone it can. When using a catalyst, these catalysts may be used only by 1 type and may be used in combination of 2 or more type. The amount of these catalysts used is usually selected in the range of 10 ⁻⁸ to 1 part by weight, preferably 10 ⁻⁷ to 10 ⁻¹ part by weight, based on 100 parts by weight of the starting aromatic dihydroxy compound.

The branched polycarbonate produced by the method of the present embodiment has a repeating unit represented by the following general formula (1) in the main chain and the branched chain.

The branched polycarbonate produced by the method of the present embodiment is represented by the following general formulas (2), (3) and (4) together with a branched structure (a) derived from a polyfunctional compound directly bonded to the main chain and the branched chain. A branched structure (b) containing at least one selected from the group consisting of branched structures can be contained.

The branched polycarbonate produced by the method of the present embodiment has a branched structure (a) with respect to the amount of the repeating unit represented by the general formula (1) and the following general formulas (2), (3), and (4). The ratio of the total substance amount of the branched structure (b) represented is preferably 0.2 to 1.0 mol%, more preferably 0.3 to 0.9 mol%, More preferably, it is 0.8 mol%. When the amount is more than 1.0 mol%, the fish eye increases and impact resistance and mechanical strength are lowered. When the amount is less than 0.2 mol%, the effect of improving the moldability tends to be reduced. Here, each “substance amount” refers to a substance amount of a component derived from each structure generated when the branched polycarbonate is hydrolyzed.

(In the formula, Ar represents a divalent aromatic residue, and Ar ′ represents a trivalent aromatic residue.)

In the above general formulas (1) and (3), Ar is also synonymous with Ar represented by HO—Ar—OH. Furthermore, Ar ′ in the above general formulas (2), (3) and (4) is bonded to a substituent (eg —COO—) which should be present at the start of branching, so that one more hydrogen atom from Ar. A trivalent aromatic residue from which etc. are removed is shown.

Further, in the branched polycarbonate produced by the method of the present embodiment, the ratio of the substance amount of the branched structure (b) to the total substance amount of the branched structure (a) and the branched structure (b) is 0.1 to 0.00. 6, preferably 0.2 to 0.6, and more preferably 0.3 to 0.6. If it exceeds 0.6, the hot water resistance tends to decrease, and if it is less than 0.1, the MIR is small and the increase in melt tension tends to be small.

Further, the ratio of the substance amount of the branched structure represented by the general formula (2) to the substance amount of the branched structure (b) represented by the general formulas (2) to (4) is 0.5 or more, Preferably it is 0.85 or more, More preferably, it is 0.9 or more. When it is less than 0.5, impact resistance and mechanical strength tend to decrease and fish eyes tend to increase.

In the present specification, the “main chain” refers to a polymer chain formed by condensation of an aromatic dihydroxy compound and a carbonic acid diester used as raw materials by a transesterification reaction. In this case, in the portion branched by the polyfunctional compound (“branched structure (a)”), the branched chain having the longest branched portion is selected from the plurality of branched chains, and this is selected as the main chain. Position as.

In the present specification, the “branched structure (a)” refers to a branched structure branched by a polyfunctional compound. For example, when 1,1,1-tris (4-hydroxyphenyl) ethane is used as the polyfunctional compound, the structure represented by the following formula becomes “branched structure (a)”, and the amount of substance of the branched structure (a) is Quantifies the hydrolyzed 1,1,1-tris (4-hydroxyphenyl) ethane.

In the present specification, the “branched structure (b)” refers to a branched structure that occurs spontaneously with respect to the main chain during the production process of the branched polycarbonate (for example, by Fries rearrangement reaction).

It is preferable that the branched polycarbonate produced according to this embodiment does not substantially contain chlorine atoms. As described in WO 2005/121210 pamphlet, etc., in this transesterification method, a branched polycarbonate is produced from an aromatic dihydroxy compound substantially free of chlorine atoms, a carbonic acid diester, and a polyfunctional compound. In such a case, a branched polycarbonate having a chlorine atom content of 10 ppb or less, preferably 1 ppb or less, can be obtained unless other compounds containing chlorine are added.

The branched polycarbonate produced according to the present embodiment has a thickness of 50 μm and a width of 30 cm, and the number of fish eyes having a size of 300 μm or more is 100 or less in a length of 1 m at an arbitrary location. The number is preferably 80 or less, more preferably 50 or less.

The hue (b ^* value) of the branched polycarbonate produced according to this embodiment is 0 to 3.0, preferably 0 to 2.5, and more preferably 0 to 1.5. When the above range is exceeded, the branched polycarbonate looks yellowish and looks bad. If necessary, the yellowness can be corrected with a colorant such as a bluing agent, but it is necessary to consider transparency.

The hue of the branched polycarbonate produced according to the present embodiment was measured by injection molding a 3.2 mm thick flat plate at a barrel temperature of 300 ° C. and a mold temperature of 90 ° C., and using a CR-400 manufactured by Konica Minolta Co., Ltd. Placed on the calibration plate and measured by the reflection method with a measurement diameter of 8 mm, the difference in b ^* value from the white calibration plate (b ^* value of the flat plate = measured value when the flat plate is placed on the white calibration plate-white calibration plate Measured value).

The branched structures (a) and (b) in the branched polycarbonate produced by the present embodiment can be quantified using reverse phase liquid chromatography after the branched polycarbonate is completely hydrolyzed. Hydrolysis of polycarbonate is performed at room temperature as described in Polymer Degradation and Stability 45 (1994), 127 to 137, and is easy to operate and has no side reactions during the decomposition process. Since it can decompose | disassemble, it is preferable and in this embodiment, it can carry out at room temperature (25 degreeC).

In the continuous production method of the branched polycarbonate according to this embodiment, a colorant, a heat stabilizer, an antioxidant, a weathering agent, an ultraviolet absorber, a release agent, a lubricant, an antistatic agent, a plasticizer, and the like are added as necessary. May be used. Furthermore, these additives and the like may be added while the polycarbonate-based resin after polymerization is in a molten state, or the pellets may be once pelletized and then the additives may be added and remelted and kneaded.

In the transesterification method, it is known that a branched structure (b) as shown in the above general formulas (2) to (4) is spontaneously generated. In the present embodiment, the branched structure may be present in the branched polycarbonate. In that case, you may reduce the usage-amount derived from a polyfunctional compound according to the quantity of the said branched structure (b). In this case, the total amount of the branched structure (a) derived from the functional compound and the branched structure (b) of the above general formulas (2) to (4) naturally generated by the transesterification method is represented by the general formula (1). 0.2 to 1.0 mol%, preferably 0.2 to 0.9 mol%, more preferably 0.3 to 0.8 mol%, based on the amount of the repeating unit substance. . When the amount is more than 1.0 mol%, the fish eye tends to increase. When the amount is less than 0.2 mol%, the MIR tends to be small and the increase in melt tension tends to be small.

When typical bisphenol A is used as the aromatic dihydroxy compound, the above general formulas (2) to (4) become the following formulas (9) to (11).

These branched structures can be quantified using reverse-phase liquid chromatography after complete hydrolysis of the branched polycarbonate. In the branched polycarbonate produced according to the present embodiment, the ratio of the amount of the branched structure (b) to the total amount of the branched structure (a) and the branched structure (b) is 0.1 to 0.6. The ratio of the substance amount of the branched structure represented by the general formula (2) to the substance amount of the branched structure (b) is 0.85 or more, and more preferably 0.9 or more.

Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the following Example.

Evaluation of each item was measured by the following method.
(1) Molecular weight (1-a) Number average molecular weight: Gel permeation chromatography (HLC-8320GPC manufactured by Tosoh Corporation, TSK-GEL Super Multipore HZ-M, 2 RI detectors), eluent tetrahydrofuran, Measurement was performed at a temperature of 40 ° C. Molecular weight was calculated | required using the conversion molecular weight calibration curve by the following Formula from the calibration curve of a standard monodisperse polystyrene (Varian's EasiVial).
M _PC = 0.3591 M _PS ^1.0388
_{(Wherein, M PC} molecular weight of the _{polycarbonate,} the _{M PS} is the molecular weight of polystyrene.)
(1-b) Weight average molecular weight: Gel permeation chromatography (HLC-8320GPC manufactured by Tosoh Corporation, two TSK-GEL Super Multipore HZ-M, RI detector), eluent = tetrahydrofuran, injection amount = 5 microliters , Measurement temperature = 40 ° C., detector = RI detector.
Preparation of measurement sample = 10 mg of branched polycarbonate was dissolved in 10 ml of methylene chloride. The molecular weight was determined from a calibration curve of standard monodisperse polystyrene (EasiVial (RED, YELLOW, GREEN) Varian) using a converted molecular weight calibration curve according to the following equation.
M _PC = 0.3591 M _PS ^1.0388
( _MPC is the molecular weight of polycarbonate, and _MPS is the molecular weight of polystyrene.)

(2) MI, MIR: MI (melt index) was measured by the method of ASTM D1238 at a temperature of 300 ° C. and a load of 1.2 kg. The MIR (branch index) was obtained by dividing the value measured with a 12 kg load by the MI value by the same method.

(3) Hue: A 15 cm × 15 cm × 3.2 mm thick plate was injection molded at a barrel temperature of 300 ° C. and a mold temperature of 90 ° C., and b ^* with a standard white plate using CR-400 manufactured by Konica Minolta ^. The difference (Δb ^* ) from the value was determined.

(4) Fisheye: Film molding machine (manufactured by Tanabe Plastic Machinery Co., Ltd., 30 mmφ single screw extruder, screw rotation speed 100 rpm, discharge rate 10 kg / hr, barrel temperature 280 ° C., T die temperature 260 ° C., roll temperature 120 ° C.) A film having a thickness of 50 μm and a width of 30 cm was formed, and the number of fish eyes having a size of 300 μm or more in an arbitrary length of 1 m was visually counted.

(5) Time to complete the grade change: After the branched polycarbonate is produced, the supply of the polyfunctional compound is stopped and the production is switched to the production of the polycarbonate with MI of 10 g / 10 min. The time until the measured value became 1 or less was determined.

(6) Amount of branched structure: After dissolving 55 mg of polycarbonate in 2 ml of tetrahydrofuran, 0.5 ml of 5 N potassium hydroxide methanol solution was added and stirred at 25 ° C. for 2 hours for complete hydrolysis. Thereafter, 0.3 ml of concentrated hydrochloric acid was added, and measurement was performed by reversed-phase liquid chromatography (LC-1100, manufactured by Agilent). Reverse-phase liquid chromatography uses an Inertsil ODS-3 column (manufactured by GL Science), a mixed eluent consisting of methanol and 0.1% aqueous phosphoric acid as the eluent, a column oven at 40 ° C., methanol / 0.1. % Phosphoric acid aqueous solution ratio was measured under the condition of starting from 20/80 and grading to 100/0, and the detection was quantified using a UV detector having a wavelength of 300 nm.

(7) Hot water resistance: The flat plate molded in (3) above was taken out after being immersed in hot water at 95 ° C. for 300 hours, and left in a constant temperature and humidity chamber maintained at 23 ° C. and 50 RH%. After 24 hours, the occurrence of craze was visually confirmed. A: No crazing, B: 1-9 occurrences, C: 10 occurrences or more.

(8) Impact resistance strength Using an injection blow molding machine ASB-650EXHS manufactured by Nissei ASB, at a barrel temperature of 295 ° C, a mold temperature core of 60 ° C, and a cavity of 30 ° C, a 5 gallon water bottle (diameter approximately 25 cm, height About 50 cm) was injection blow molded.
(8-a) Bottle strength: The water bottle formed as described above is filled with water, and the same bottle is dropped from four heights of 1.5 m above, below, diagonally above, and diagonally below to check for cracks. Evaluated. (A: no crack, C: crack)
(8-b) Charpy strength: In accordance with ISO 306, a test piece was prepared by injection molding at a barrel temperature of 300 ° C. and a mold temperature of 90 ° C., and tested with a notch.

<Example 1>
A branched polycarbonate was produced using the production system shown in FIG. Stirrer tank type

first polymerizers

3A and 3B are equipped with

stirrers

6A and 6B having an internal volume of 100 liters and anchor type stirring blades. The stirring tank type second polymerization vessel 3C and the stirring tank type third polymerization vessel 3D are equipped with

stirrers

6C and 6D having a volume of 50 liters and having anchor type stirring blades. The wire contact flow type first and

second polymerization vessels

108A and 108B have a porous plate 102A having five holes, a porous plate 102B having three holes, and SUS316L wire-shaped

guides

103A and 103B having a diameter of 1 mm and a length of 8 m. To do. Stirrer tank type

1st polymerization devices

3A and 3B are used by switching alternately, and after stirrer tank type 2nd polymerization device 3C, they are used continuously.

80 kg of a polymerization raw material consisting of bisphenol A as an aromatic dihydroxy compound and diphenyl carbonate (a molar ratio of bisphenol A of 1.06) as a carbonic acid diester, and a disodium salt of bisphenol A as a catalyst (in terms of sodium atoms, in the polymerization raw material) 75 wt ppb) with respect to bisphenol A was charged into the stirring tank type first polymerization vessel 3A from the polymerization raw material inlet 1A. The reaction temperature was 180 ° C., the reaction pressure was atmospheric pressure, and the nitrogen gas flow rate was 1 liter / hr. After 4 hours, the outlet 5A was opened, and the molten prepolymer 4A was supplied to the stirred tank type second polymerization vessel 3C at a flow rate of 7 liter / hr.

Thereafter, the stirring tank type first polymerization vessel 3B was operated in the same manner as the stirring tank type first polymerization vessel 3A to obtain a molten prepolymer 4B. After the stirring tank type first polymerizer 3A is emptied, the outlet 5A of the stirring tank type first polymerizer 3A is closed, the outlet 5B of the stirring tank type first polymerizer 3B is opened, and the molten prepolymer 4B is supplied at a flow rate of 7 It was supplied from the stirring tank type first polymerization device 3B to the stirring tank type second polymerization device 3C at a rate of 1 liter / hr. By repeating this, the

molten prepolymers

4A and 4B were continuously supplied to the stirred tank type second polymerization vessel 3C alternately.

The stirring tank type second polymerization vessel 3C was maintained at a reaction temperature of 230 ° C. and a reaction pressure of 13.0 kPa to obtain a molten prepolymer 4C. After the volume of the molten prepolymer 4C reached 20 liters, a part of the molten prepolymer 4C was continuously withdrawn and supplied to the stirring tank type third polymerizer 3D so as to keep the internal volume of 20 liters constant.

The stirring tank type third polymerization vessel 3D was maintained at a reaction temperature of 265 ° C. and a reaction pressure of 2.6 kPa to obtain a molten prepolymer 4D. After the volume of the molten prepolymer 4D reached 20 liters, a part of the molten prepolymer 4D was withdrawn and continuously supplied to the wire contact flow type first polymerizer 108A so as to keep the internal volume of 20 liters constant.

The wire contact flow type first polymerization vessel 108A was maintained at a reaction temperature of 265 ° C. and a reaction pressure of 400 Pa to obtain a molten prepolymer 109A. After the volume of the molten prepolymer 109A reaches 10 liters, a part of the molten prepolymer 109A is withdrawn so as to keep the volume of 10 liters, and continuously passed through the line mixer 110 to the wire contact flow type second polymerizer 108B. Supplied. The number average molecular weight of the molten prepolymer 109A was 7500.

A polyfunctional compound (polyfunctional compound) in which polyfunctional compound 1,1,1-tris (4-hydroxyphenyl) ethane and phenol as a solvent are uniformly dissolved in a line mixer 110 maintained at a temperature of 265 ° C. and a rotational speed of 15 rpm /Phenol=1/1.5 is mixed at a temperature of 180 ° C. from the pipe 111 in such an amount that the polyfunctional compound has a molar ratio of 0.004 with respect to the bisphenol A skeleton in the molten prepolymer 109A. did. The number average molecular weight of the molten prepolymer immediately before entering the wire contact flow type second polymerization vessel 108B was measured and found to be 4000.

The wire contact flow type second polymerization vessel 108B was maintained at a reaction temperature of 265 ° C. and a reaction pressure of 118 Pa to obtain a branched polycarbonate. After the volume of the branched polycarbonate reached 10 liters, it was continuously extracted as a strand from the outlet 107B using the discharge pump 106B so as to maintain the capacity of 10 liters, and was cooled and cut to obtain a pellet-like branched polycarbonate. Table 1 shows the evaluation results of the obtained branched polycarbonate. In Tables 1 to 3, T ₁ represents the temperature (° C.) of the low molecular weight polycarbonate introduced into the final polymerization vessel, and T ₂ represents the temperature (° C.) of the branched polycarbonate polymerized in the final polymerization vessel. ΔT was 0 ° C.

<Example 2>
The solvent of Example 1 was changed to a solution in which acetone and phenol were uniformly dissolved (mixed at a weight ratio of polyfunctional compound / acetone / phenol = 1 / 2.5 / 0.1). The uniformly dissolved solution was supplied to the line mixer 110 from the pipe 111 at a temperature of 40 ° C. The wire contact flow type first polymerization vessel 108A was maintained at a reaction temperature of 265 ° C. and a reaction pressure of 790 Pa to obtain a molten prepolymer 109A. The number average molecular weight of the molten prepolymer 109A was 5500. It was 4200 when the number average molecular weight of the melted prepolymer immediately before entering the wire contact flow type second polymerization vessel 108B was measured. In addition, the supply rate of the melted prepolymer in the step (A) was adjusted so that the flow rate of the melted prepolymer per wire in the final polymerization vessel became the value shown in Table 1. Except for these changes, the same procedure as in Example 1 was performed. Table 1 shows the evaluation results of the obtained branched polycarbonate. ΔT was 0 ° C.

<Example 3>
The solvent of Example 2 was changed to a prepolymer having a number average molecular weight of 2500. The weight mixing ratio of the branching agent and the prepolymer was 1: 2. The uniformly dissolved solution was supplied from the pipe 111 to the line mixer 110 at a temperature of 180 ° C. The number average molecular weight of the molten prepolymer 109A was 5700. The number average molecular weight of the molten prepolymer immediately before entering the wire contact flow type second polymerization vessel 108B was 4900. In addition, the supply rate of the melted prepolymer in the step (A) was adjusted so that the flow rate of the melted prepolymer per wire in the final polymerization vessel became the value shown in Table 1. Except for these changes, the same procedure as in Example 2 was performed. Table 1 shows the evaluation results of the obtained branched polycarbonate. ΔT was 0 ° C.

<Example 4>
The solvent of Example 2 was changed to diphenyl carbonate (DPC) and bisphenol A (BPA). The uniformly dissolved solution was supplied from the pipe 111 to the line mixer 110 at a temperature of 180 ° C. The weight mixing ratio of the branching agent, DPC and BPA was 1.5: 0.5: 1. Further, disodium salt of bisphenol A (75 weight ppb with respect to bisphenol A in the polymerization raw material in terms of sodium atom) was added as a catalyst. The number average molecular weight of the molten prepolymer 109A was 5700. It was 4200 when the number average molecular weight of the molten prepolymer immediately before entering the wire contact flow type second polymerization vessel 108B was measured. In addition, the supply rate of the melted prepolymer in the step (A) was adjusted so that the flow rate of the melted prepolymer per wire in the final polymerization vessel became the value shown in Table 1. Except for these changes, the same procedure as in Example 2 was performed. Table 1 shows the evaluation results of the obtained branched polycarbonate. ΔT was 0 ° C.

<Example 5>
The solvent of Example 2 was changed to DPC. The weight mixing ratio of the branching agent and DPC was 1: 0.67. The uniformly dissolved solution was supplied from the pipe 111 to the line mixer 110 at a temperature of 180 ° C. The number average molecular weight of the molten prepolymer 109A was 5700. The number average molecular weight of the molten prepolymer immediately before entering the wire contact flow type second polymerization vessel 108B was 4000. In addition, the supply rate of the melted prepolymer in the step (A) was adjusted so that the flow rate of the melted prepolymer per wire in the final polymerization vessel became the value shown in Table 1. Except for these changes, the same procedure as in Example 2 was performed. Table 1 shows the evaluation results of the obtained branched polycarbonate. ΔT was 0 ° C.

<Example 6>
Acetone was used as a solvent for the polyfunctional compound, and it was charged into the stirred tank type third polymerization vessel 3D instead of being charged into the line mixer 110. In addition, the supply rate of the melted prepolymer in the step (A) was adjusted so that the flow rate of the melted prepolymer per wire in the final polymerization vessel became the value shown in Table 1. Except for these changes, the same procedure as in Example 2 was performed. Although some MI fluctuation was observed, a branched polycarbonate could be produced stably. Table 1 shows the evaluation results of the obtained branched polycarbonate. ΔT was 0 ° C.

<Example 7>
The polyfunctional compound of Example 2 was 4- [4- [1,1-bis (4-hydroxyphenyl) ethyl] -α, α-dimethylbenzyl] phenol and the solvent was changed to acetone. The wire contact flow type first polymerization vessel 108A was maintained at a reaction temperature of 265 ° C. and a reaction pressure of 1000 Pa to obtain a molten prepolymer 109A. In addition, the supply rate of the melted prepolymer in the step (A) was adjusted so that the flow rate of the melted prepolymer per wire in the final polymerization vessel became the value shown in Table 1. Except for these changes, the same procedure as in Example 2 was performed. The evaluation results of the obtained branched polycarbonate are shown in Table 2. ΔT was −0.2 ° C.

<Example 8>
Phenol was used as a solvent (mixed at a weight ratio of polyfunctional compound / phenol = 6/4), and a twin screw extruder with a vent (Ikegai) was placed behind the outlet 107B of the wire contact flow down type second polymerizer in FIG. PCM 30 mm, L / D30, temperature 265 ° C.) installed by Steel Co., Ltd. Line mixer with polyfunctional compound 1,1,1-tris (4-hydroxyphenyl) ethane (molar ratio 0.004 with respect to bisphenol A skeleton) The same procedure as in Example 2 was performed except that powder was fed from the vent port of the above twin screw extruder without feeding from 110. The evaluation results of the obtained branched polycarbonate are shown in Table 2. In addition, the supply rate of the melted prepolymer in the step (A) was adjusted so that the flow rate of the melted prepolymer per wire in the final polymerization vessel became the value shown in Table 1. ΔT was 25 ° C.

<Comparative Example 1>
A double-screw extruder with a vent (PCM 30 mm, L / D30, temperature 265 ° C., manufactured by Ikegai Steel Co., Ltd.) is installed behind the outlet 107B of the wire contact flow-down type second polymerizer of FIG. Except that 1-tris (4-hydroxyphenyl) ethane (molar ratio of 0.004 with respect to bisphenol A skeleton) was not supplied from the line mixer 110 but was charged in powder form from the vent port of the above twin screw extruder. Was carried out in the same manner as in Example 2. The evaluation results of the obtained branched polycarbonate are shown in Table 3. In addition, the supply rate of the melted prepolymer in the step (A) was adjusted so that the flow rate of the melted prepolymer per wire in the final polymerization vessel became the value shown in Table 1. ΔT was 0 ° C.

<Comparative Example 2>
In FIG. 1, the line mixer 110 was replaced with a vented single screw extruder, the pipe from 107A was connected to the supply port of the single screw extruder, and the outlet of the single screw extruder was connected to the pipe to 101B. Except that polyfunctional compound 1,1,1-tris (4-hydroxyphenyl) ethane (molar ratio 0.004 with respect to bisphenol A skeleton) was charged in powder form from the vent port of the single screw extruder Performed as in Example 2. The evaluation results of the obtained branched polycarbonate are shown in Table 3. In addition, the supply rate of the melted prepolymer in the step (A) was adjusted so that the flow rate of the melted prepolymer per wire in the final polymerization vessel became the value shown in Table 1. ΔT was 0 ° C.

<Comparative Example 3>
In FIG. 1, the line mixer 110 is replaced with a vented twin screw extruder (Ikegai Steel Co., Ltd., PCM 30 mm, L / D30, temperature 265 ° C.), and the pipe from 107A is connected to the supply port of the twin screw extruder. The exit of the extruder was connected to the feed port of a horizontal polymerization reactor (not shown). The polyfunctional compound 1,1,1-tris (4-hydroxyphenyl) ethane (molar ratio 0.004 with respect to the bisphenol A skeleton) was charged at room temperature from the vent port of the above twin screw extruder. Further, the final polymerization was carried out by installing a horizontal polymerization reactor instead of the polymerization vessel 108B as the final polymerization device connected to the twin screw extruder. The temperature of the horizontal polymerization reactor was set to 320 ° C. Except for these changes, the same procedure as in Example 2 was performed. The evaluation results of the obtained branched polycarbonate are shown in Table 3. ΔT was 30 ° C.

<Comparative example 4>
In FIG. 1, the line mixer 110 is replaced with a vented twin screw extruder (Ikegai Steel Co., Ltd., PCM 30 mm, L / D 30, temperature 265 ° C.), and the pipe from 107A is connected to the supply port of the twin screw extruder. The exit of the extruder was connected to the feed port of a horizontal polymerization reactor (not shown). Polyfunctional compound 1,1,1-tris (4-hydroxyphenyl) ethane (molar ratio 0.004 with respect to bisphenol A skeleton) and DPC were charged at normal temperature from the vent port of the above twin screw extruder. The weight ratio of branching agent to DPC was 1: 0.6. Further, the final polymerization apparatus connected to the twin-screw extruder was installed with a horizontal polymerization reaction volatilizer instead of the polymerization apparatus 108B to carry out final polymerization. The temperature of the horizontal polymerization reactor was set to 320 ° C. Except for these changes, the same procedure as in Example 2 was performed. The evaluation results of the obtained branched polycarbonate are shown in Table 3. ΔT was 25 ° C.

<Comparative Example 5>
In Example 2, the polyfunctional compound and the solvent were not added. In order to produce a polymer having MI = 3, the supply amount to the final polymerization vessel 108B was extremely reduced, and the supply amount per wire was set to 0.2 kg / hr. By increasing the residence time at 103B, a polymer with MI = 3 was produced, but a polymer with a lot of fish eyes was obtained. The productivity was also considerably worse than that in Example 2.

<Example 9>
A branched polycarbonate was produced using the production system shown in FIG. Stirrer tank type

first polymerizers

3A and 3B are equipped with

stirrers

second polymerization vessels

guides

103A and 103B having a diameter of 1 mm and a length of 8 m. To do. Stirred tank type

first polymerizers

3A and 3B are used by switching alternately, and the stirred tank type second polymerizer 3C and thereafter are used continuously.

80 kg of polymerization raw material consisting of bisphenol A as an aromatic dihydroxy compound and diphenyl carbonate as carbonic acid diester (molar ratio of bisphenol A: 1.07), disodium salt of bisphenol A as a catalyst (bisphenol in the polymerization raw material in terms of sodium atom) 50 weight ppb) with respect to A was charged into the stirred tank type first polymerization vessel 3A. The reaction temperature was 185 ° C., the reaction pressure was atmospheric pressure, and the nitrogen gas flow rate was 1 liter / hr. After 4 hours, the outlet 5A is opened, and the molten prepolymer 4A is fed to the stirred tank type second polymerization device 3C at a flow rate such that the flow rate of the molten prepolymer per wire in the final polymerization vessel becomes the value shown in Table 2. Supplied.

Thereafter, the stirring tank type first polymerization vessel 3B was operated in the same manner as the stirring tank type first polymerization vessel 3A to obtain a molten prepolymer 4B. After the stirring tank type first polymerizer 3A is emptied, the outlet 5A of the stirring tank type first polymerizer 3A is closed and the outlet 5B of the stirring tank type first polymerizer 3B is opened, and the molten prepolymer 4B is finally The molten prepolymer per wire in the polymerization vessel was supplied from the stirring vessel type first polymerization vessel 3B to the stirring vessel type second polymerization vessel 3C at such a flow rate that the value shown in Table 2 was obtained. By repeating this, the

molten prepolymers

The stirring tank type second polymerization vessel 3C was maintained at a reaction temperature of 232 ° C. and a reaction pressure of 12.8 kPa, thereby obtaining a molten prepolymer 4C. After the volume of the molten prepolymer 4C reached 20 liters, a part of the molten prepolymer 4C was continuously withdrawn and supplied to the stirring tank type third polymerizer 3D so as to keep the internal volume of 20 liters constant.

The stirring tank type third polymerization vessel 3D was maintained at a reaction temperature of 266 ° C. and a reaction pressure of 2.5 kPa, thereby obtaining a molten prepolymer 4D. After the volume of the molten prepolymer 4D reached 20 liters, a part of the molten prepolymer 4D was withdrawn and continuously supplied to the wire contact flow type first polymerizer 108A so as to keep the internal volume of 20 liters constant.

The wire contact flow type first polymerization vessel 108A was maintained at a reaction temperature of 266 ° C. and a reaction pressure of 770 Pa to obtain a molten prepolymer 109A. After the volume of the molten prepolymer 109A reached 10 liters, a part of the molten prepolymer 109A was extracted so as to keep the volume of 10 liters. The number average molecular weight of the molten prepolymer 109A was 5000. The melted prepolymer 109A extracted is continuously supplied to the wire contact flow type second polymerization vessel 108B via the line mixer 110, and ½ quantity is supplied to the wire contact flow type third triple. Continuously supplied to the combiner 108C.

Polyfunctional compound 1,1,1-tris (4-hydroxyphenyl) ethane and phenol as a solvent are uniformly dissolved at a weight ratio of 6: 4 in a line mixer 110 maintained at a temperature of 266 ° C. and a rotation speed of 15 rpm. The solution thus obtained was supplied from the pipe 111 at a temperature of 185 ° C. in such an amount that the polyfunctional compound had a molar ratio of 0.003 with respect to the bisphenol A skeleton in the molten prepolymer 109A. It was 4400 when the number average molecular weight of the molten prepolymer immediately before entering the wire contact flow type second polymerization vessel 108B was measured.

The wire contact flow type second polymerization vessel 108B was maintained at a reaction temperature of 266 ° C. and a reaction pressure of 122 Pa to obtain a branched polycarbonate. After the volume of the branched polycarbonate reached 10 liters, the discharge pump 106B was used to continuously extract the strands from the outlet 107B as a strand so as to maintain the capacity of 10 liters. The evaluation results of the obtained branched polycarbonate are shown in Table 3.

The wire contact flow type third polymerization vessel 108C was maintained at a reaction temperature of 266 ° C. and a reaction pressure of 135 Pa to obtain a polycarbonate. After the polycarbonate volume reaches 10 liters, the discharge pump 106C is used to continuously extract the strands from the outlet 107C as a strand so as to maintain the capacity of 10 liters. A pellet-like linear polycarbonate having an eye measurement value of 0 was obtained. After 50 hours of continuous operation, the flow ratio of 106A and 106D is changed to 50:50, so that the production ratio of branched polycarbonate and linear polycarbonate is changed, and the production volume is controlled without loss of brand switching. Were produced at the same time. The evaluation results of the obtained branched polycarbonate are shown in Table 2.

The production method of the present invention is a method for producing a branched polycarbonate with a transesterification method that can reduce loss at the time of brand switching, is excellent in hue and hot water resistance, and has little fish eye, has a large MIR, and is used for extrusion. And a branched polycarbonate excellent in blow moldability can be provided.

1A, 1B: Polymerization raw material inlet, 1C, 1D: Prepolymer inlet, 2A, 2B, 2C, 2D, 105A, 105B, 105C ... Vent port, 3A, 3B ... Stirred tank type first polymerizer, 3C ... Stirring Tank type second polymerizer, 3D ... Stirred tank type third polymerizer, 4A, 4B, 4C, 4D, 109A ... Molten prepolymer, 5A, 5B, 5C, 5D, 107A, 107B, 107C ... Outlet, 6A, 6B, 6C, 6D ... stirrer, 7C, 7D, 8, 106A ... transfer pump, 101A, 101B, 101C ... prepolymer inlet, 102A, 102B, 102C ... perforated plate, 103A, 103B, 103C ... wire guide,

104A

104B, 104C ... Gas supply port, 106B, 106C ... Discharge pump, 108A ... Wire contact flow-down type first polymerizer, 108B ... Wire contact Downflow type second polymerizer, 108C ... wire-contacting downflow type third polymerization vessel, 109B, 109C ... molten polymer, 110 ... melting mixer (line mixer), 111 ... polyfunctional compound introduction pipe, 120 ... bifurcation.

Claims

(A) a step of producing a low molecular weight polycarbonate having a number average molecular weight of 1000 to 10,000 by an ester exchange method from an aromatic dihydroxy compound and a carbonic acid diester;
(B) adding and mixing a polyfunctional compound in a liquid state to the low molecular weight polycarbonate;
(C) a step of continuously producing a branched polycarbonate by performing a polymerization reaction until the melt index of the low molecular weight polycarbonate is 10 g / 10 min or less and the branching index is 14 or more;
A method for continuously producing a branched polycarbonate comprising
The method according to claim 1, wherein the range of ΔT (° C) defined by the following formula (I) is -20 ° C to 20 ° C or less.
ΔT = T 2 −T 1 (I)
[Wherein T 1 represents the temperature (° C.) of the low molecular weight polycarbonate introduced into the final polymerization vessel in the step (C), and T 2 represents a branched polycarbonate polymerized by the final polymerization vessel in the step (C). The T 2 is 285 ° C. or lower. ]
The said polyfunctional compound is added to the melt mixer installed in the middle of piping between the apparatus which performs the said (A) process, and the apparatus which performs the said (C) process in the state melt | dissolved in the solvent. The method according to 1 or 2.
The solvent is at least one selected from the group consisting of phenols, carbonic acid diesters, ketones, ethers, mixtures and reactants of aromatic dihydroxy compounds and carbonic acid diesters, and low molecular weight polycarbonates having a number average molecular weight of 5000 or less. The method of claim 3, wherein
The method according to any one of claims 1 to 4, wherein the solvent is a depolymerization solvent.
The method according to any one of claims 1 to 5, further comprising a step of producing a polycarbonate by carrying out a polymerization reaction until the melt index becomes 100 g / 10 min or less following the step (A).
The apparatus for performing the step (A) performs the step (C) via a pipe having a branch portion branched so as to lead to the apparatus for performing the step (C) and the apparatus for performing the step (D). Connected to a device for performing and the device for performing the step (D),
The said polyfunctional compound is a method of Claim 6 added to the melt mixer installed in the middle of piping between the said branch part and the apparatus which performs the said (C) process.
A branched polycarbonate produced by the method according to any one of claims 1 to 7.