JP5720092B2 - Method for producing polycarbonate - Google Patents

Description

  The present invention relates to a method for producing a polycarbonate having excellent heat characteristics, color tone, mechanical strength, low refractive index, and excellent optical properties such as a large Abbe number, and more specifically, a dihydroxy compound having a specific structure. The present invention relates to a polycarbonate production process for producing a polycarbonate by transesterifying a diester with a carbonic acid diester, and a method for producing a polycarbonate in which a reaction tank for carrying out the transesterification is brought into contact with an aromatic hydroxy compound.

  In recent years, global warming due to the increase and accumulation of carbon dioxide emissions has been feared to bring about climate change, etc., and carbon neutral plant-derived monomers are used as raw materials even after disposal after use. There is a need to develop polycarbonate. In order to reduce the impact on the global environment, polycarbonate using raw materials obtained from biomass resources is known, and among them, it is possible to obtain polycarbonate by transesterification with diphenyl carbonate using plant-derived monomer isosorbide Is known (see, for example, Patent Document 1). A polycarbonate obtained by copolymerizing isosorbide and bisphenol A is known (see, for example, Patent Document 2), and further, it is known that the rigidity of the polycarbonate is improved by copolymerizing isosorbide and an aliphatic diol. (For example, refer to Patent Document 3). And in the method of producing an aromatic polycarbonate by reacting an aromatic dihydroxy compound and a carbonic acid diester by a transesterification reaction, a method for producing an aromatic polycarbonate using production equipment washed by a specific washing method is known. (For example, see Patent Document 4).

British Patent 1,079,686 JP-A-56-055425 International Publication No. 2004/111106 Pamphlet JP 2002-363276 A

  A polycarbonate obtained by transesterifying a dihydroxy compound having a specific structure represented by the following formula (1) and a carbonic acid diester, represented by a monomer having a heterocyclic structure such as isosorbide, is transparent. , High heat resistance, low refractive index, and low Abbe number, it is expected to be used in applications such as optical compensation films.

(However, a hydrogen atom is not bonded to an oxygen atom in the structural formula (1).)
However, the polycarbonate having such a structure is poor in thermal stability as compared with the conventional aromatic polycarbonate having a bisphenol structure. There was a case of coloring.

  In particular, the reaction tank after the transesterification reaction may cause impurities such as coloring and lowering of the molecular weight to remain and accumulate. Therefore, not only when producing polycarbonates having different repeating structures in the same reaction vessel, but also when producing polycarbonates having the same repeating structures, impurities that degrade physical properties can be removed at regular intervals. preferable.

More specifically, for example, it is preferable that an organic solvent or the like is brought into contact with the reaction vessel before the polycarbonate is produced, and the polycarbonate remaining in the reaction vessel is depolymerized and discharged out of the reaction vessel.
However, as a dihydroxy compound having a specific structure, for example, a polycarbonate resin obtained by using isosorbide has a slower depolymerization rate than a polycarbonate having an aromatic diol skeleton, and therefore, an organic solvent or the like can be used by a conventionally known method. Impurities may not be sufficiently removed even if they are brought into contact with each other. Therefore, when manufacturing polycarbonate using isosorbide again with equipment that manufactured polycarbonate using isosorbide, polycarbonate having a different structure may be used. In the case of production, the polycarbonate produced subsequently may be deteriorated in color tone, deteriorated in physical properties and delayed in polymerization rate.

  An object of the present invention is to provide a method for producing a high-quality polycarbonate by preventing deterioration of physical properties such as color tone and molecular weight of a polycarbonate obtained by transesterifying a dihydroxy compound having a specific structure and a carbonic acid diester. It is in.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have made a reaction tank having a history of use in polycarbonate production before performing the transesterification in the reaction tank. It was found that a polycarbonate having a large Abbe number, a small birefringence, and excellent transparency, thermal stability, and color tone can be produced by bringing the compound into contact with a specific compound and then performing a transesterification reaction. That is, the gist of the present invention resides in the following [1] to [6].

  [1] A polycarbonate production process for producing a polycarbonate by transesterifying a dihydroxy compound having a structure represented by the following structural formula (1) in the molecule with a carbonic acid diester, and the ester exchange before the ester exchange. A process for producing a polycarbonate, comprising a reaction tank treatment step of bringing a reaction tank into contact with an aromatic hydroxy compound.

(However, a hydrogen atom is not bonded to an oxygen atom in the structural formula (1).)
[2] The method for producing a polycarbonate according to [1], further including a reaction vessel pretreatment step in which a reaction vessel and a dihydroxy compound represented by the following general formula (2) are brought into contact before the reaction vessel treatment step.

(In formula (2), X represents a direct bond, an alkylene group having 10 or less carbon atoms, or a divalent group having 10 or less carbon atoms having an ether bond.)
[3] Before the reaction vessel treatment step, there is a reaction vessel treatment step in which a mixed solution of the dihydroxy compound represented by the general formula (2) and the carbonic acid diester is brought into contact with the reaction vessel, [1] or The method for producing a polycarbonate according to [2].

[4] The polystyrene-equivalent number average molecular weight (Mn) of the polycarbonate contained in the treatment liquid withdrawn from the reaction vessel after at least one treatment selected from the reaction vessel treatment step and the reaction vessel pretreatment step is 4000 or less. , [1] to [3] The method for producing a polycarbonate according to any one of [3].
[5] It has the same kind as the polycarbonate manufactured after the reaction vessel treatment step, and has a reaction vessel post-treatment step in which a polycarbonate having a polystyrene-equivalent number average molecular weight (Mn) of 4000 to 18000 is brought into contact with the reaction vessel. [1] The method for producing a polycarbonate according to any one of [4].

  [6] Any of [1] to [5], wherein the dihydroxy compound having a structure represented by Structural Formula (1) in the molecule is a compound having a heterocyclic ring represented by Structural Formula (3) below: A process for producing the polycarbonate according to claim 1.

  According to the method for producing a polycarbonate of the present invention, it is possible to stably produce a polycarbonate having excellent transparency, color tone, heat resistance, moldability, and mechanical strength and excellent optical properties.

DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will be described in detail below. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention. It is not limited to the contents.
The polycarbonate production method of the present invention comprises a polycarbonate production process for producing a polycarbonate by transesterifying a dihydroxy compound having a structure represented by the following structural formula (1) in the molecule with a carbonic acid diester, and the ester exchange. It has a reaction tank treatment step in which a reaction tank for transesterification and an aromatic hydroxy compound are brought into contact with each other before performing.

(However, a hydrogen atom is not bonded to an oxygen atom in the structural formula (1).)
Hereinafter, the dihydroxy compound having a structure represented by the structural formula (1) in the molecule and the carbonic acid diester may be collectively referred to as “raw material monomer”.
<Dihydroxy compound>
The dihydroxy compound having a structure represented by the structural formula (1) in the present invention is not particularly limited as long as it has a structure represented by the structural formula (1) in the molecule. Are 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-methylphenyl) fluorene, 9,9-bis (4 -(2-hydroxyethoxy) -3-isopropylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-isobutylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) ) -3-tert-butylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-cyclohexylphenyl) fluorene, 9,9-bis (4) (2-hydroxyethoxy) -3-phenylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3,5-dimethylphenyl) fluorene, 9,9-bis (4- (2-hydroxy Ethoxy) -3-tert-butyl-6-methylphenyl) fluorene 9,9-bis (4- (3-hydroxy-2,2-dimethylpropoxy) phenyl) fluorene, etc., and has an aromatic group in the side chain, A compound having an ether group bonded to an aromatic group in the main chain, an anhydrosugar alcohol represented by a dihydroxy compound represented by the following structural formula (3), and a cyclic such as spiroglycol represented by the following structural formula (4) The compound which has an ether structure is mentioned, These may be used independently and may be used in combination of 2 or more type.

Among these, the dihydroxy compound represented by the structural formula (3) is particularly preferable, and examples of the dihydroxy compound include isosorbide, isomannide, and isoide which are related to stereoisomers. It may be used in combination, or two or more may be used in combination.
In particular, among these dihydroxy compounds, isosorbide obtained by dehydrating condensation of sorbitol produced from glucose, which is abundant as a plant-derived resource, is easy to obtain and produce, optical characteristics, Most preferable in terms of formability and carbon neutrality.

  As a raw material monomer of the polycarbonate according to the present invention, a structural unit derived from a dihydroxy compound other than the dihydroxy compound according to the present invention (hereinafter may be referred to as “other dihydroxy compound”) may be additionally used. As other dihydroxy compounds, ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5 -Aliphatic dihydroxy compounds such as heptanediol and 1,6-hexanediol, oxyalkylene glycols such as diethylene glycol, triethylene glycol and tetraethylene glycol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclo Xanthodimethanol, tricyclodecane dimethanol, pentacyclopentadecane dimethanol, 2,6-decalin dimethanol, 1,5-decalin dimethanol, 2,3-decalin dimethanol, 2,3-norbornane dimethanol, 2, Alicyclic dihydroxy compounds such as 5-norbornane dimethanol and 1,3-adamantane dimethanol, 2,2-bis (4-hydroxyphenyl) propane (which is the compound name of bisphenol A), 2,2-bis ( 4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-diethylphenyl) propane, 2,2-bis (4-hydroxy- (3,5-diphenyl) phenyl ) Propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, , 2-bis (4-hydroxyphenyl) pentane, 2,4′-dihydroxy-diphenylmethane, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-5-nitrophenyl) methane, 1,1-bis (4 -Hydroxyphenyl) ethane, 3,3-bis (4-hydroxyphenyl) pentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4'-dihydroxydiphenylsulfone, Bis (4-hydroxyphenyl) sulfide, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dichlorodiphenyl ether, 9,9-bis (4- (2-hydroxyethoxy-2-methyl) Phenyl) fluorene, 9,9-bis (4-hydroxyphenyl) ) Bisphenol compounds such as fluorene and 9,9-bis (4-hydroxy-2-methylphenyl) fluorene. Among these, 2,2-bis (4-hydroxyphenyl) propane, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, from the viewpoint of optical properties, availability, and ease of handling, 1,2-cyclohexanedimethanol and tricyclodecane dimethanol are preferred.

  By using these other dihydroxy compounds, it is possible to obtain effects such as improvement in flexibility, improvement in heat resistance, improvement in moldability, etc. of the obtained polycarbonate, but inclusion of structural units derived from other dihydroxy compounds If the ratio is too large, the performance of the original optical characteristics and the heat resistance may be reduced. Therefore, in the present invention, the ratio of the dihydroxy compound of the present invention to the total dihydroxy compound constituting the polycarbonate is preferably 20 mol% or more, more preferably 30 mol% or more, and particularly preferably 50 mol% or more. It is.

<Carbonated diester>
Examples of the carbonic acid diester used in the method for producing a polycarbonate of the present invention include diphenyl carbonate, substituted diphenyl carbonate typified by ditolyl carbonate, dimethyl carbonate, diethyl carbonate, and di-t-butyl carbonate. Particularly preferred are diphenyl carbonate and substituted diphenyl carbonate. These carbonic acid diesters may be used alone or in combination of two or more.

  The carbonic acid diester is preferably used in a molar ratio of 0.90 to 1.10, more preferably in a molar ratio of 0.96 to 1.04, based on all dihydroxy compounds used in the reaction. When this molar ratio is less than 0.90, the terminal OH group of the produced polycarbonate is increased, so that the thermal stability of the polymer is deteriorated or a desired high molecular weight product cannot be obtained. On the other hand, if the molar ratio exceeds 1.10, the rate of the transesterification reaction decreases under the same conditions, and it becomes difficult to produce a polycarbonate having a desired molecular weight. The amount of residual carbonic acid diester in the coalescence increases, and this residual carbonic acid diester may cause odor during molding or in the molded product.

<Transesterification>
In the method for producing a polycarbonate according to the present invention, the polycarbonate is produced by transesterifying the dihydroxy compound having a structure represented by the structural formula (1) in the molecule with the carbonic acid diester. This process of producing a polycarbonate by transesterification is called a polycarbonate production process.

  In the polycarbonate production process, it is preferable to use a polymerization catalyst (a transesterification catalyst) in order to advance the transesterification reaction efficiently. Here, an alkali metal compound and / or an alkaline earth metal compound is used as the polymerization catalyst. A basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, or an amine compound can be used in combination with an alkali metal compound and / or an alkaline earth metal compound. It is particularly preferred to use only metal compounds and / or alkaline earth metal compounds.

  Examples of the alkali metal compound used as the polymerization catalyst include sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, cesium hydrogen carbonate, sodium carbonate, potassium carbonate. , Lithium carbonate, cesium carbonate, sodium acetate, potassium acetate, lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium borohydride, potassium borohydride, lithium borohydride, Cesium borohydride, sodium phenyl borohydride, potassium phenyl borohydride, lithium phenyl borohydride, cesium phenyl borohydride, sodium benzoate, potassium benzoate, lithium benzoate, benzoic acid Cium, 2 sodium hydrogen phosphate, 2 potassium hydrogen phosphate, 2 lithium hydrogen phosphate, 2 cesium hydrogen phosphate, 2 sodium phenyl phosphate, 2 potassium phenyl phosphate, 2 lithium phenyl phosphate, 2 cesium phenyl phosphate, Sodium, potassium, lithium, cesium alcoholate, phenolate, disodium salt of bisphenol A, 2 potassium salt, 2 lithium salt, 2 cesium salt and the like.

Examples of the alkaline earth metal compound include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, Examples thereof include magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate. In this specification, the terms “alkali metal” and “alkaline earth metal” are respectively referred to as “first” in the long-period periodic table (Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005).
Synonymous with “Group metal” and “Group 2 metal”.

These alkali metal compounds and / or alkaline earth metal compounds may be used alone or in combination of two or more.
Specific examples of basic boron compounds used in combination with alkali metal compounds and / or alkaline earth metal compounds include tetramethyl boron, tetraethyl boron, tetrapropyl boron, tetrabutyl boron, trimethylethyl boron, trimethylbenzyl boron, trimethyl Sodium salt such as phenyl boron, triethylmethyl boron, triethylbenzyl boron, triethylphenyl boron, tributylbenzyl boron, tributylphenyl boron, tetraphenyl boron, benzyltriphenyl boron, methyltriphenyl boron, butyltriphenyl boron, potassium salt, lithium Examples thereof include salts, calcium salts, barium salts, magnesium salts, and strontium salts.

Examples of the basic phosphorus compound include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphine, and quaternary phosphonium salts.
Examples of the basic ammonium compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, Triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide Sid, butyl triphenyl ammonium hydroxide, and the like.

  Examples of the amine compound include 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2 -Dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline and the like.

These basic compounds may be used alone or in combination of two or more.
When an alkali metal compound and / or an alkaline earth metal compound is used as the polymerization catalyst, the amount used is usually 0.1 μmol to 25 μmol as a metal conversion amount with respect to 1 mol of all dihydroxy compounds used in the reaction, Preferably it is 0.5 micromol-20 micromol, More preferably, it exists in the range of 0.5 micromol-15 micromol. If the amount of the polymerization catalyst used is too small, the polymerization activity necessary to produce a polycarbonate having a desired molecular weight cannot be obtained. On the other hand, if the amount of the polymerization catalyst used is too large, the hue of the resulting polycarbonate deteriorates, By-products are generated and fluidity is lowered and gel is generated more frequently, making it difficult to produce polycarbonate having the target quality.

In the present invention, the dihydroxy compound, for example, the dihydroxy compound represented by the structural formula (3) may be supplied as a solid, heated and supplied in a molten state, or supplied as an aqueous solution. Also good.
On the other hand, alicyclic dihydroxy compounds and other dihydroxy compounds may be supplied as solids, heated and supplied in a molten state, or supplied as an aqueous solution if soluble in water. May be.

When these raw material dihydroxy compounds are supplied in a molten state or in an aqueous solution, there is an advantage that they can be easily measured and transported when industrially produced.
In the present invention, the dihydroxy compound, for example, the dihydroxy compound represented by the structural formula (3), the alicyclic dihydroxy compound, and another dihydroxy compound used as necessary is reacted with a carbonic acid diester in the presence of a polymerization catalyst. The method is usually performed in a multistage process of two or more stages. Specifically, the first stage reaction is carried out at a temperature of 140 to 220 ° C., preferably 150 to 200 ° C. for 0.1 to 10 hours, preferably 0.5 to 3 hours. From the second stage onward, the reaction temperature is raised while gradually reducing the pressure of the reaction system from the pressure of the first stage, and at the same time, the phenol generated at the same time is removed from the reaction system. Is 200 Pa or less and a polycondensation reaction is performed under the temperature range of 210-280 degreeC.

  In the pressure reduction in this polycondensation reaction, it is important to control the balance between temperature and pressure in the reaction system. In particular, if either one of the temperature and the pressure is changed too quickly, unreacted monomers are distilled out, the molar ratio of the dihydroxy compound and the carbonic acid diester may be changed, and the degree of polymerization may be lowered. For example, when isosorbide and 1,4-cyclohexanedimethanol are used as the dihydroxy compound, 1,4-cyclohexanedimethanol is used when the molar ratio of 1,4-cyclohexanedimethanol to the total dihydroxy compound is 50 mol% or more. Since methanol easily distills out as a monomer, the reaction is carried out under a reduced pressure of about 13 kPa while the temperature is increased at a rate of temperature increase of 40 ° C. or less per hour, and further up to about 6.67 kPa. When the polycondensation reaction is performed at a temperature of 200 ° C. to 250 ° C. at a pressure of 200 Pa or less at a temperature rising rate of 40 ° C. or less per hour under the pressure of This is preferable because an elevated polycarbonate is obtained.

  Further, for example, when the molar ratio of 1,4-cyclohexanedimethanol is less than 50 mol%, particularly when the molar ratio is 30 mol% or less, the total amount of 1,4-cyclohexane dimethanol is 1,4-cyclohexane dimethanol. Compared with the case where the molar ratio of methanol is 50 mol% or more, the viscosity rises rapidly. For example, the temperature is raised to 40 ° C. or less per hour until the pressure in the reaction system is reduced to about 13 kPa. The reaction is carried out while increasing at a rate, and further, the reaction is carried out at a pressure of up to about 6.67 kPa while the temperature is increased at a rate of temperature rise of 40 ° C. or more per hour, preferably 50 ° C. or more per hour. When a polycondensation reaction is finally performed at a temperature of 220 ° C. to 290 ° C. under a reduced pressure of 200 Pa or less, a polycarbonate having a sufficiently increased degree of polymerization is obtained. There.

The type of reaction may be any of batch type, continuous type, or a combination of batch type and continuous type.
In the method of the present invention, when a polycarbonate is produced by a melt polymerization method, a phosphoric acid compound, a phosphorous acid compound, or a metal salt thereof can be added during polymerization for the purpose of preventing coloring.

  As the phosphoric acid compound, one or more of trialkyl phosphates such as trimethyl phosphate and triethyl phosphate are preferably used. These are preferably added in an amount of 0.0001 mol% or more and 0.005 mol% or less, and more preferably 0.0003 mol% or more and 0.003 mol% or less, based on all dihydroxy compounds used in the reaction. If the addition amount of the phosphorus compound is less than the above lower limit, the effect of preventing coloring is small, and if it is more than the above upper limit, it may cause haze to increase, or conversely promote coloring or reduce heat resistance. is there.

When adding a phosphorous acid compound, the heat stabilizer shown below can be selected arbitrarily and used. In particular, trimethyl phosphite, triethyl phosphite, trisnonylphenyl phosphite, trimethyl phosphate, tris (2,4-di-tert-butyl 0-phenyl) phosphite, bis (2,4-di-tert-butylphenyl) ) One or more of pentaerythritol diphosphites can be suitably used. These phosphorous acid compounds are preferably added in an amount of 0.0001 mol% or more and 0.005 mol% or less, and 0.0003 mol% or more and 0.003 mol% or less with respect to all dihydroxy compounds used in the reaction. It is preferable. If the amount of the phosphite compound is less than the above lower limit, the effect of preventing coloring is small, and if it is more than the above upper limit, it may cause haze to increase, or conversely promote coloring or reduce heat resistance. Sometimes.

  The phosphoric acid compound and the phosphorous acid compound or their metal salts can be added in combination. In this case, the addition amount is the total amount of the phosphoric acid compound and the phosphorous acid compound or their metal salts, as described above. The total content of dihydroxy compounds is preferably 0.0001 mol% or more and 0.005 mol% or less, and more preferably 0.0003 mol% or more and 0.003 mol% or less. If the amount added is less than the above lower limit, the effect of preventing coloring is small, and if it is more than the above upper limit, haze may be increased, or conversely, coloring may be promoted or heat resistance may be lowered.

In addition, as a metal salt of a phosphoric acid compound and a phosphorous acid compound, these alkali metal salts and zinc salts are preferable, and zinc salts are particularly preferable. Among these zinc phosphate salts, long-chain alkyl zinc phosphate salts are preferable.
The polycarbonate thus produced can be blended with a heat stabilizer in order to prevent a decrease in molecular weight or a deterioration in hue at the time of molding or the like.

  Examples of such heat stabilizers include phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid and esters thereof. Specific examples include triphenyl phosphite, tris (nonylphenyl) phosphite, tris. (2,4-di-tert-butylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, mono Butyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2-methylene bis (4,6- G-t rt-butylphenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tributyl phosphate, Triethyl phosphate, trimethyl phosphate, triphenyl phosphate, diphenyl monoorthoxenyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, 4,4′-biphenylenediphosphinic acid tetrakis (2,4-di-tert-butylphenyl), benzenephosphone Examples thereof include dimethyl acid, diethyl benzenephosphonate, and dipropyl benzenephosphonate. Among them, trisnonylphenyl phosphite, trimethyl phosphate, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2 , 6-Di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, dimethyl benzenephosphonate and the like are preferably used.

These heat stabilizers may be used alone or in combination of two or more.
Such a heat stabilizer can be further added in addition to the addition amount added at the time of melt polymerization. That is, after blending an appropriate amount of a phosphorous acid compound or phosphoric acid compound to obtain a polycarbonate, and further blending a phosphorous acid compound by a blending method described later, an increase in haze during polymerization, coloring, and By avoiding a decrease in heat resistance, more heat stabilizers can be blended, and hue deterioration can be prevented.

The blending amount of these heat stabilizers is preferably 0.0001 to 1 part by weight, more preferably 0.0005 to 0.5 part by weight, and 0.001 to 0.2 part by weight when polycarbonate is 100 parts by weight. Part is more preferred.
The polycarbonate of the present invention can be blended with an antioxidant generally known for the purpose of antioxidant.

  Examples of the antioxidant include pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-laurylthiopropionate), glycerol-3-stearylthiopropionate, triethylene glycol-bis [ 3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] , Pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1 , 3,5-trimethyl-2,4 6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, N, N-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 3, 5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 4,4′-biphenylenediphosphinic acid tetrakis (2, 4-di-tert-butylphenyl), 3,9-bis {1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2 , 4,8,10-tetraoxaspiro (5,5) undecane and the like.

These antioxidants may be used alone or in combination of two or more.
The blending amount of these antioxidants is preferably 0.0001 to 0.5 parts by weight when the polycarbonate is 100 parts by weight.
<Reactor treatment process>
One of the features of the present invention is to have a step of bringing the reaction vessel for carrying out the transesterification into contact with the aromatic hydroxy compound before carrying out the transesterification in the polycarbonate production step, and this step is called a reaction vessel treatment step. .

Any method can be selected as a method for bringing the reaction vessel for transesterification into contact with the aromatic hydroxy compound. Specifically, for example, the aromatic hydroxy compound is sprinkled or sprayed into the reaction vessel. A method, a method of retaining (accumulating) a certain amount or more of the aromatic hydroxy compound in the reaction tank, or a method combining them can be employed.
Moreover, when holding an aromatic hydroxy compound in a reaction tank, it is also preferable to stir. The stirring speed in this case is arbitrary, but the stirring Reynolds number is preferably 20 or more, more preferably 50 or more, and particularly preferably 100 or more.

The time required for the reaction vessel treatment step can be arbitrarily selected, but is usually 0.5 hours to 10 hours, more preferably 1 hour to 8 hours, and particularly preferably 3 hours to 6 hours. Below time.
Further, the temperature (liquid temperature) in the reaction vessel during the reaction vessel treatment step can be arbitrarily selected as long as the solution in the reaction vessel does not boil and does not solidify, but is usually 150 ° C. or more and 300 ° C. It is 170 degrees C or less, More preferably, it is 170 degree | times or more and 280 degrees C or less, Most preferably, it is 190 degree | times or more and 250 degrees C or less.

The aromatic hydroxy compound used in the reaction vessel treatment step is discharged after the treatment step. As a discharge method, in addition to a method of opening a valve provided in the reaction vessel, a discharge pipe or tube is placed in the reaction vessel. It may be inserted into and extracted using a pump or the like. Furthermore, the inside of the reaction vessel can be kept under reduced pressure and discharged. In addition, after discharging | emitting an aromatic hydroxy compound, you may make it contact with an aromatic hydroxy compound again, and may repeat a reaction tank process process in multiple times.

As the aromatic hydroxy compound, any aromatic compound having a hydroxy group may be used, and the number of hydroxy groups may be one or plural. Is preferably one, that is, an aromatic monohydroxy compound in that it can be efficiently depolymerized.
The aromatic ring may be a single ring or a large number of condensed rings, but a polycarbonate produced by preventing the polymer compound from remaining in the reaction vessel by lowering the molecular weight. Are preferably low in number, and more preferably have 3 or less rings, and particularly preferably monocyclic ones. Used.

The aromatic ring may have a substituent other than a hydroxy group, specifically, for example, an alkyl group which may have a branch having 1 to 12 carbon atoms, or a branch having 1 to 12 carbon atoms. Examples thereof include a carboxy group which may have, an alkoxy group which may have 1 to 12 carbon atoms, a nitro group, an amino group and a halogen atom.
In particular, even if the aromatic hydroxy compound remains in the reaction tank after the reaction tank treatment step, the aromatic hydroxy compound to be used is produced by the transesterification reaction in order to prevent any influence on the transesterification reaction. The same ones are preferably used. Specifically, for example, when diphenyl carbonate is used as the carbonic acid diester, phenol is produced by transesterification. In such a case, phenol is suitably used as the aromatic hydroxy compound. Also, the aromatic hydroxy compound having a lower molecular weight is preferable, and phenol is preferably used also from the viewpoint that the used aromatic hydroxy compound can be easily discharged out of the reaction tank by an operation such as temperature increase or reduced pressure. It is done.

<Reaction tank pretreatment process>
Furthermore, in this invention, you may have the process of making the reaction tank which transesterifies and the dihydroxy compound represented by following General formula (2) contact before the said reaction tank processing process, It is called a reaction tank pretreatment process.

  An arbitrary method can be selected as a method for bringing the reaction vessel for transesterification into contact with the dihydroxy compound represented by the general formula (2). Specifically, for example, the general formula (2) in the reaction vessel can be selected. A method of sprinkling or spraying the dihydroxy compound represented by the formula, a method of holding (collecting) a certain amount or more of the dihydroxy compound represented by the general formula (2) in the reaction tank, or a method combining them is adopted. can do.

Moreover, when holding an aromatic hydroxy compound in a reaction tank, it is also preferable to stir. The stirring speed in this case is arbitrary, but the stirring Reynolds number is preferably 10 or more, more preferably 50 or more, and particularly preferably 100 or more.
The time required for the reaction vessel treatment step can be arbitrarily selected, but is usually 0.2 hours or more and 10 hours or less, more preferably 0.5 hours or more and 7 hours or less, and particularly preferably 1 hour. It is 5 hours or less.

Further, the temperature (liquid temperature) in the reaction vessel during the reaction vessel treatment step can be arbitrarily selected as long as the solution in the reaction vessel does not boil and does not solidify, but is usually 150 ° C. or more and 300 ° C. It is 170 degrees C or less, More preferably, it is 170 degree | times or more and 280 degrees C or less, Most preferably, it is 180 degree | times or more and 250 degrees C or less.
The dihydroxy compound represented by the general formula (2) used in the reaction tank treatment step is discharged after the treatment step. As a discharge method, in addition to a method of opening a valve provided in the tank, a discharge pipe is used. Alternatively, the tube may be inserted into the reaction vessel and extracted using a pump or the like. Furthermore, the inside of the reaction vessel can be kept under reduced pressure and discharged. In addition, after discharging | emitting the dihydroxy compound represented by General formula (2), you may make it contact again with the dihydroxy compound represented by General formula (2), and may repeat a reaction tank process process in multiple times.

In the general formula (2), X represents a direct bond, an alkylene group having 10 or less carbon atoms, or a divalent group having 10 or less carbon atoms having an ether bond, and the dihydroxy group represented by the general formula (2) remaining after contact. The number of carbon atoms is preferably 5 or less, more preferably 3 or less, in that it is easy to remove the compound from the reaction vessel.
Specific examples of the dihydroxy compound represented by the general formula (2) include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, and polyethylene glycol.

  When the reaction vessel is brought into contact with the dihydroxy compound represented by the general formula (2), depolymerization of the polycarbonate remaining in the reaction vessel proceeds. However, if these depolymerized products and the dihydroxy compound represented by the general formula (2) remain in the reaction tank, the residue reacts with the carbonic acid diester compound in the production of the polycarbonate carried out after the contact to produce the polycarbonate. In doing so, it may be incorporated into the structure of the polycarbonate. Therefore, in order to remove the aliphatic dihydroxy compound remaining after the contact from the reaction tank, the inside of the reaction tank is depressurized, heated in a gas stream such as nitrogen, or the vapor pressure is low and represented by the general formula (2). It is preferable to remove the residue by mixing and extracting with another solvent having high compatibility with the dihydroxy compound.

  In the reaction vessel pretreatment step, it is preferable to use a carbonic acid diester together with the dihydroxy compound represented by the general formula (2) in order to enhance the depolymerization effect. In this case, the depolymerization of the polycarbonate remaining in the reaction vessel proceeds more effectively. However, if these depolymerized products, dihydroxy compounds represented by the general formula (2), carbonic acid diesters, etc. remain in the reaction tank, the molar ratio of the dihydroxy compound and the carbonic acid diester is produced during the production of the polycarbonate after contact. However, there is a possibility that a polycarbonate having a target molecular weight cannot be obtained because it deviates from the intended raw material input amount. Therefore, in order to remove the dihydroxy compound and carbonic acid diester remaining after the contact from the reaction tank, the inside of the reaction tank is depressurized, heated in a gas stream such as nitrogen, or the vapor pressure is low and compatible with the aliphatic dihydroxy compound. It is preferable to remove the residue by mixing with another solvent having a high viscosity.

<Polycarbonate discharged after contact>
In the polycarbonate production method according to the present invention, when the reaction vessel treatment step and the reaction vessel pretreatment step are performed, the depolymerization of the polycarbonate remaining in the reaction vessel proceeds to produce a lower molecular weight polycarbonate. Therefore, after the reaction vessel treatment step and the reaction vessel pretreatment step, polycarbonate is present in the liquid withdrawn from the reaction vessel, but the polystyrene-equivalent number average molecular weight (hereinafter, abbreviated as Mn) of the polycarbonate. ) Is desirably 4000 or less, more preferably 3000 or less, and particularly preferably 2500 or less. When the Mn of the polycarbonate is 4000 or more, the polycarbonate may remain in the reaction vessel even after the reaction vessel treatment step and the reaction vessel pretreatment step, which may cause deterioration of the color tone of the polycarbonate to be produced.

<Other processing>
In the polycarbonate production method of the present invention, the polycarbonate is produced after the reaction vessel treatment step, but it is preferable that the reaction vessel is brought into contact with the polycarbonate after the reaction vessel treatment step and before the polycarbonate production.
In this case, it is preferable to use a polycarbonate having a polystyrene-equivalent number average molecular weight (Mn) of 4000 to 18000, more preferably 6000 to 14000.

Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples.
In the following, the physical properties and characteristics of the polycarbonate resin and the polycarbonate resin composition were evaluated by the following methods.
・ Viscosity average molecular weight (Mv)
The intrinsic viscosity [η] at 20 ° C. in methylene chloride was measured using an Ubbelohde viscometer, and the viscosity average molecular weight (Mv) was determined from the following formula.
[Η] = 1.23 × 10 ⁻⁴ (Mv) ^0.83
-Number average molecular weight (Mn), weight average molecular weight (Mw)
It measured on condition of the following using gel permeation chromatography (GPC).
Equipment: Tosoh Corporation product, HLC-8020
Columns: Four columns (diameter: 7.8 mm, length: 300 mm) packed with TSK 5000HLX, 4000HLX, 3000HLX, and 2000HLX (all manufactured by Tosoh Corporation) were used as fillers.
Detector: Refractometer Eluent: Tetrahydrofuran Calibration curve: Standard polystyrene (Molecular weight; 761 (Mw / Mn ≦ 1.14), 2000 (Mw / Mn ≦ 1.20), 4000 (Mw / M) Mn ≦ 1.06), 9000 (Mw / Mn ≦ 1.04), 17500 (Mw / Mn ≦ 1.03), 50000 (Mw / Mn ≦ 1.03), 233000 (Mw / Mn ≦ 1.05) , 600,000 (Mw / Mn ≦ 1.05) and 900000 (Mw / Mn ≦ 1.05).
Operation: Mw and Mn were determined in terms of polystyrene from the chart obtained by detecting the difference in refractive index.
(2) Hue measurement Using a colorimetric color difference meter (Nippon Denshoku Industries Co., Ltd. ZE-2000), the tristimulus value of the color was measured by the C light source transmission method. An index (YI) value was calculated.

Yellow index (YI) = 100 × (1.28X−1.06Z) / Y
<Distillation of isosorbide>
Here, the distillation method of isosorbide used for the production of the heterocyclic ring-containing polycarbonate resins A and B is as follows.
After isosorbide was added to the distillation vessel, the pressure was gradually reduced and then warmed to dissolve at an internal temperature of about 100 ° C. Thereafter, distillation started at an internal temperature of 160 ° C. The pressure at this time was 133-266 Pa. After the initial distillation, distillation was performed at an internal temperature of 160 to 170 ° C., a tower top temperature of 150 to 157 ° C., and 133 Pa. After completion of distillation, argon was added to return to normal pressure. The obtained distilled product was cooled and pulverized under an argon stream to obtain distilled and purified isosorbide. This product was sealed and stored at room temperature with AGELESS (Mitsubishi Gas Chemical Co., Ltd.) enclosed in an aluminum laminate bag under a nitrogen stream.

(Example 1 to Example 6)
(Production of heterocycle-containing polycarbonate A-1)
(Reference Example 1)
4077 g of distilled isosorbide, 2347 g of tricyclodecane dimethanol (hereinafter abbreviated as “TCDDM”), 8538 g of diphenyl carbonate, and 5.09 ml of an aqueous cesium carbonate solution adjusted to 9.8 × 10 ⁻⁶ mol / ml as a catalyst. In a nitrogen atmosphere, as a first step of the reaction, the heating bath temperature was heated to 150 ° C., and the raw materials were dissolved while stirring as necessary (about 15 minutes). .

Subsequently, the pressure was reduced from normal pressure to 13.3 kPa over 40 minutes, and the generated phenol was extracted out of the reaction vessel while increasing the heating bath temperature to 190 ° C. over 40 minutes.
After maintaining the entire reaction vessel at 190 ° C. for 15 minutes, as a second step, the heating bath temperature was increased to 240 ° C. over 30 minutes. Ten minutes after entering the temperature rise, the pressure in the reaction vessel was reduced to 0.200 kPa or less over 30 minutes, and the generated phenol was distilled off. After reaching a predetermined stirring torque, the reaction was stopped, and molten polycarbonate was extracted from the reaction vessel outlet.

(Reference Example 2)
6700 g of bisphenol A, 6570 g of diphenyl carbonate, and 1.50 ml of an aqueous cesium carbonate solution adjusted to 9.8 × 10 ⁻⁶ mol / ml as a catalyst were placed in a reaction vessel, and the first stage of the reaction was performed in a nitrogen atmosphere. As a process, the heating tank temperature was heated to 220 ° C., and the raw materials were dissolved while stirring as necessary (about 15 minutes).

Next, while reducing the pressure from normal pressure to 13.3 kPa over 60 minutes, the generated phenol was extracted out of the reaction vessel.
After holding the entire reaction vessel at 220 ° C. for 60 minutes, as a second step, the heating bath temperature was increased to 280 ° C. over 20 minutes. Ten minutes after entering the temperature rise, the pressure in the reaction vessel was reduced to 0.200 kPa or less over 40 minutes, and the generated phenol was distilled off. After 150 minutes, a predetermined stirring torque was reached, the reaction was stopped, and molten polycarbonate was extracted from the outlet of the reaction vessel.

( Reference Example 3 )
After the production of polycarbonate in the same manner as in Reference Example 1, 4000 g of dissolved phenol was put into a reaction vessel, the heating bath temperature was heated to 220 ° C. in a nitrogen atmosphere, and the stirring Reynolds number was about 120 as necessary. Stirring under the following stirring conditions. After 60 minutes, the heating tank temperature was heated to 250 ° C., stirred for 120 minutes under stirring conditions where the stirring Reynolds number was about 120, and then the pressure in the reaction vessel was reduced to 4.4 kPa over 30 minutes, It extracted out of the reaction container. After the stirring was stopped, the depolymerized polycarbonate oligomer was extracted from the reaction vessel outlet.

Next, a polycarbonate was produced in the same manner as in Reference Example 2. The viscosity average molecular weight (Mv), yellow index (YI), and number average molecular weight (Mn) of the polycarbonate oligomer were measured by the above methods. The results are shown in Table 1.
( Reference Example 4 )
In the same manner as in Reference Example 1, after producing polycarbonate, 6000 g of ethylene glycol was added, and the heating bath temperature was heated to 200 ° C. in a nitrogen atmosphere, and the stirring conditions under which the stirring Reynolds number was about 120 as necessary. Stir with. After 120 minutes, the pressure in the reaction vessel was reduced to 4.4 kPa over 30 minutes, and ethylene glycol was extracted out of the reaction vessel. After the stirring was stopped, the depolymerized polycarbonate oligomer was extracted from the reaction vessel outlet. After completion of the extraction, 4000 g of dissolved phenol was put into a reaction vessel, heated in a nitrogen atmosphere to a heating bath temperature of 220 ° C., and stirred as necessary under stirring conditions with a stirring Reynolds number of about 120. . After 60 minutes, the heating tank temperature was heated to 250 ° C. and stirred for 120 minutes under stirring conditions where the stirring Reynolds number was about 120, and then the pressure in the reaction vessel was reduced to 4.4 kPa over 30 minutes to react phenol. It was pulled out of the container. After the stirring was stopped, the depolymerized polycarbonate oligomer was extracted from the reaction vessel outlet.

Next, a polycarbonate was produced in the same manner as in Reference Example 2. Table 1 shows various physical property values measured in the same manner as in Example 1.
( Reference Example 5 )
After producing the polycarbonate in the same manner as in Reference Example 1, 5400 g of triethylene glycol was charged into the reaction vessel, and the heating tank temperature was heated to 240 ° C. in a nitrogen atmosphere, and the stirring Reynolds number was about 120 as necessary. Stirring under the following stirring conditions. After 50 minutes, the heating bath temperature was heated to 300 ° C. and stirred for 120 minutes under stirring conditions where the stirring Reynolds number was about 120. Thereafter, the pressure in the reaction vessel was reduced to 4.4 kPa over 30 minutes, Ethylene glycol was extracted out of the reaction vessel. After the stirring was stopped, the depolymerized polycarbonate oligomer was extracted from the reaction vessel outlet. After completion of the extraction, 4000 g of dissolved phenol was put into a reaction vessel, heated in a nitrogen atmosphere to a heating bath temperature of 220 ° C., and stirred as necessary under stirring conditions with a stirring Reynolds number of about 120. . After 60 minutes, the heating tank temperature was heated to 250 ° C. and stirred for 120 minutes under stirring conditions where the stirring Reynolds number was about 120, and then the pressure in the reaction vessel was reduced to 4.4 kPa over 30 minutes to react phenol. It was pulled out of the container. After the stirring was stopped, the depolymerized polycarbonate oligomer was extracted from the reaction vessel outlet.

Next, a polycarbonate was produced in the same manner as in Reference Example 2. Table 1 shows various physical property values measured in the same manner as in Example 1.
Example 4
After the production of polycarbonate in the same manner as in Reference Example 1, 4500 g of bisphenol A and 4222 g of diphenyl carbonate were added, the heating bath temperature was heated to 260 ° C. in a nitrogen atmosphere, and the stirring Reynolds number was about 120 as necessary. Stir under conditions. After the stirring was stopped, the depolymerized polycarbonate oligomer was extracted from the reaction vessel outlet. After completion of the extraction, 4000 g of dissolved phenol was put into a reaction vessel, heated in a nitrogen atmosphere to a heating bath temperature of 220 ° C., and stirred as necessary under stirring conditions with a stirring Reynolds number of about 120. . After 60 minutes, the heating tank temperature was heated to 250 ° C. and stirred for 120 minutes under stirring conditions where the stirring Reynolds number was about 120, and then the pressure in the reaction vessel was reduced to 4.4 kPa over 30 minutes to react phenol. It was pulled out of the container. After the stirring was stopped, the depolymerized polycarbonate oligomer was extracted from the reaction vessel outlet.

With respect to 73.070 parts by weight of isosorbide, 109.140 parts by weight of diphenyl carbonate and 2.0 × 10 ⁻¹ parts by weight of cesium carbonate as a catalyst were put into a reaction vessel, and the first reaction was conducted in a nitrogen atmosphere. As a step, the heating bath temperature was heated to 150 ° C., and the raw materials were dissolved while stirring as necessary (about 15 minutes).
Next, the pressure was reduced from normal pressure to 13.3 kPa over 40 minutes, and the generated phenol was extracted out of the reaction vessel while raising the heating bath temperature to 190 ° C. over 40 minutes.

Next, a polycarbonate was produced in the same manner as in Reference Example 2. Table 1 shows various physical property values measured in the same manner as in Example 1.
( Reference Example 6 )
After the production of polycarbonate in the same manner as in Reference Example 1, 4000 g of dissolved phenol was put into a reaction vessel, the heating bath temperature was heated to 150 ° C. in a nitrogen atmosphere, and the stirring Reynolds number was about 120 as necessary. Stirring under the following stirring conditions. After 20 minutes, the heating tank temperature was heated to 170 ° C. and stirred for 60 minutes under stirring conditions where the Reynolds number was about 120, and then the pressure in the reaction vessel was reduced to 4.4 kPa over 30 minutes to react phenol. It was pulled out of the container. After the stirring was stopped, the depolymerized polycarbonate oligomer was extracted from the reaction vessel outlet.

Next, a polycarbonate was produced in the same manner as in Reference Example 2. Table 1 shows various physical property values measured in the same manner as in Example 1.
(Example 6)
After washing in the same manner as in Example 1, 6700 g of bisphenol A, 6570 g of diphenyl carbonate, and 1.50 ml of an aqueous cesium carbonate solution adjusted to 9.8 × 10 ⁻⁶ mol / ml as a catalyst were put into a reaction vessel, In a nitrogen atmosphere, as a first step of the reaction, the heating bath temperature was heated to 220 ° C., and the raw materials were dissolved while stirring as necessary (about 15 minutes).

Next, while reducing the pressure from normal pressure to 13.3 kPa over 60 minutes, the generated phenol was extracted out of the reaction vessel.
After holding the entire reaction vessel at 220 ° C. for 60 minutes, as a second step, the heating bath temperature was increased to 280 ° C. over 20 minutes. Ten minutes after entering the temperature rise, the pressure in the reaction vessel was reduced to 0.200 kPa or less over 40 minutes, and the generated phenol was distilled off. After 100 minutes, the reaction was stopped, and molten polycarbonate (polystyrene equivalent number average molecular weight (Mn) 14300) was extracted from the reaction vessel outlet.

Next, a polycarbonate was produced in the same manner as in Reference Example 2. Table 1 shows various physical property values measured in the same manner as in Example 1. Table 1 shows various physical property values measured in the same manner as in Example 1.
(Comparative Example 1)
After producing a polycarbonate in the same manner as in Reference Example 1, a polycarbonate was produced in the same manner as in Reference Example 2. Table 1 shows various physical property values measured in the same manner as in Example 1.

(Comparative Example 2)
After the production of polycarbonate in the same manner as in Reference Example 1, 5400 g of triethylene glycol was charged into the reaction vessel, the heating bath temperature was heated to 240 ° C. in a nitrogen atmosphere, and the stirring Reynolds number was about 120 if necessary. The mixture was stirred under the following stirring conditions. After 50 minutes, the heating bath temperature was heated to 300 ° C. and stirred for 120 minutes, and then the pressure in the reaction vessel was reduced to 4.4 kPa over 30 minutes, and triethylene glycol was extracted out of the reaction vessel. After the stirring was stopped, the depolymerized polycarbonate oligomer was extracted from the reaction vessel outlet.

  Next, a polycarbonate resin was produced in the same manner as in Reference Example 2. Table 1 shows various physical property values measured in the same manner as in Example 1.

  From the above results, it can be seen that by performing the reaction vessel treatment step of the present invention, an excellent polycarbonate having excellent mechanical properties due to its high molecular weight, little coloration and high transparency can be produced.

Claims (4)

A polycarbonate production process for producing a polycarbonate by transesterifying a compound having a heterocyclic ring represented by the following structural formula (3) and a carbonic acid diester;
A reaction vessel treatment step in which the reaction vessel used in the production process is brought into contact with the aromatic hydroxy compound before transesterification in the reaction vessel ; and
A polycarbonate and the same kind of manufacturing after the reactor step, and characterized in that a polystyrene-reduced number-average molecular weight (Mn) has a polycarbonate 6 000-18000, the reaction vessel after-treatment step of contacting a reaction vessel To
A method for producing polycarbonate.

2. The production of polycarbonate according to claim 1, further comprising a reaction vessel pretreatment step of bringing a reaction vessel into contact with a dihydroxy compound represented by the following general formula (2) before the reaction vessel treatment step. Method.

(In formula (2), X represents a direct bond, an alkylene group having 10 or less carbon atoms, or a divalent group having 10 or less carbon atoms having an ether bond.)   Before the reaction vessel treatment step, it has a reaction vessel pretreatment step of bringing a mixed solution of the dihydroxy compound represented by the general formula (2) and the carbonic acid diester into contact with the reaction vessel. The manufacturing method of the polycarbonate of Claim 1 or Claim 2.   The polystyrene-equivalent number average molecular weight (Mn) of the polycarbonate contained in the treatment liquid withdrawn from the reaction vessel after at least one treatment selected from the reaction vessel treatment step and the reaction vessel pretreatment step is 4000 or less. The method for producing a polycarbonate according to any one of claims 1 to 3.