JP2002069168A - Method for producing polycarbonate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate resin having a molecular weight distribution which is close to a monodisperse, and extremely narrow and sharp, whereby particularly, an amount of low molecular weight oligomer is very few and the amount of volatile matter originating from the oligomer in heat-molding is none, and therefore the above polycarbonate is excellent in industrial use. SOLUTION: A polycarbonate oligomer is obtained by reacting a carbonate raw material and a dihydroxy compound. The polycarbonate resin is obtained wherein the oligomer having a viscosity average molecular weight of 5,000 or below, as starting material, is interfacial polycondensed, without end terminator, using an amine having a basicity pKa of 10 or below as hydrochloric acid salt, as a catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polycarbonate resin having a monodispersed molecular weight distribution. The polycarbonate resin produced by the method of the present invention has an extremely narrow molecular weight distribution, and in particular, has extremely low molecular weight oligomers, and almost no volatiles derived from the oligomers during heat molding.

[0002]

2. Description of the Related Art As is well known, polycarbonate resins are widely used in the production of various molded products. For example, the substrate of an optical recording medium such as an optical disk or a magneto-optical disk
It is mainly manufactured by injection molding of polycarbonate resin. Injection molding of such precision products requires
It is required that the amount of volatile oligomers derived from polycarbonate adhere to a stamper or a mold. However, the volatility of the polycarbonate oligomers is closely related to the content thereof, and there was no material whose content could be significantly reduced except for the solvent-extracted product.

[0003] Conventionally, as one method for improving the physical properties of polycarbonate resins, efforts have been made to study a method for producing a polycarbonate resin having a low oligomer content and a narrow molecular weight distribution. For example, Japanese Patent Application Laid-Open No. 55-52321 discloses that a reaction between bisphenol A and phosgene is carried out at a low temperature to produce an oligomer having a narrow molecular weight distribution, which is then used as a terminal stopper (which is synonymous with a terminal capping agent. , Referred to as a terminating agent in the present specification) to produce a polycarbonate resin having a high molecular weight and a narrow molecular weight distribution.

Japanese Patent Application Laid-Open No. 1-278528 discloses that an oligomer is produced by reacting bisphenol A with phosgene in the presence of a terminal stopper,
To produce a polycarbonate resin having a narrow molecular weight distribution by performing polymerization in two steps. JP-A-3-109420 discloses that bisphenol A and phosgene are reacted in a first pipe reactor, a terminal stopper is added to the reaction product solution, and then the reaction product is allowed to flow into a tank reactor via a second pipe reactor. It is described that a polycarbonate oligomer is produced by reacting. According to the publication, a polycarbonate resin having a narrow molecular weight distribution was obtained by adding bisphenol A to this polycarbonate oligomer and performing polymerization in two stages.

[0005] JP-A-6-336522 and JP-A-7-165899 disclose that a prepolymer is produced by reacting bisphenol A with phosgene in the absence of a terminal terminator and then terminating the prepolymer. It is described that a polycarbonate resin having a low oligomer content and a narrow molecular weight distribution can be obtained by adding an agent and performing interfacial polymerization. These publications disclose that a polycarbonate resin having a molecular weight distribution (Mw / Mn) of about 2.0 was obtained.
It seems to contradict that the publication 109109 discloses that the molecular weight distribution is broadened by delaying the addition of the terminal terminator.

Further, Eur. Describes a relationship between the glass transition point and the molecular weight of polycarbonate. Pol
ym. J. vol. 18, P563-567 (198
When Mw / Mn is calculated from the glass transition point described in these publications according to 2), the value is much more than 2 and close to 3. In view of these points, the molecular weight distribution of the polycarbonate resin described in these documents is:
If measured precisely, it seems to be quite wide.

The purpose of the resins described in these documents is to reduce volatiles derived from oligomers generated during heat molding by reducing low molecular weight oligomers. However, not all polymers can completely remove low-molecular-weight oligomers, and a relatively preferred material is one that has been reprecipitated or extracted using a poor solvent (Japanese Unexamined Patent Publication No. 278929, JP-A-64-6020, and JP-A-4-306227), the oligomers of these materials are not completely removed, they are still insufficient, and the solvent used is separated. Because of the necessity of incorporating a process, it was unavoidable that the cost would increase considerably.

As another method for improving the melt fluidity of a polycarbonate resin, a method of sealing the terminal of a polycarbonate molecule with a compound having a long-chain alkyl group such as a long-chain alkylphenol or a long-chain alcohol is also studied. (British Patent No. 965457, U.S. Pat.
240756, JP-A-51-34992 and JP-A-60-203632). Many reports have also been made on condensation catalysts (US Pat. No. 316).
No. 0606, No. 3173891 and No. 318443
No. 1, No. 3,240,756 and No. 3,275,601), all of which are aimed at improving the reaction rate, and also use a terminal terminator in combination.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a process for producing a low-volatile polycarbonate resin having a very narrow molecular weight distribution and containing almost no low-molecular-weight oligomers.

[0010]

The gist of the present invention is to provide a polycarbonate oligomer obtained by reacting a carbonate raw material with a dihydroxy compound and having a viscosity average molecular weight (Mv) of 5,000 or less as calculated by the following formula. The present invention provides a method for producing a polycarbonate resin, comprising: performing an interfacial polycondensation using an oligomer as a starting material and an amine having a basicity having a pKa as a hydrochloride of 10 or less as a catalyst in the absence of a terminal stopper. .

Ηsp / C = [η] × (1 + 0.28ηsp) [η] = 1.23 × 10 ⁻⁴ × Mv ^0.83

Wherein ηsp is the specific viscosity of the methylene chloride solution of the polycarbonate resin measured at 20 ° C., and C is the concentration of this methylene chloride solution. The methylene chloride solution has a polycarbonate resin concentration of 0.6 g.
/ Dl. )

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method for producing a polycarbonate resin of the present invention, a polycarbonate oligomer as a starting material is produced by reacting a carbonate material with a dihydroxy compound. Here, the carbonate raw material means a carbonate bond in the polycarbonate main chain by a polymer formation reaction such as a polycondensation reaction or an exchange reaction.

[0014]

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And a representative example of which is phosgene. Examples of the dihydroxy compound include an aliphatic dihydroxy compound and an aromatic dihydroxy compound. Examples of the aromatic dihydroxy compound include an aromatic compound having two phenolic hydroxyl groups. Thus, the polycarbonate resin according to the method of the present invention reacts, for example, an aromatic compound having two phenolic hydroxyl groups typically represented by bisphenol A with phosgene to form an oligomer having an Mv of 5,000 or less. By performing interfacial polycondensation using the oligomer as a starting material in the absence of a terminal stopper and in the presence of an amine catalyst having a pKa as a hydrochloride of 10 or less, such as pyridine hydrochloride or quinoline hydrochloride, Can be manufactured.

The production method will be described in more detail. As the aromatic compound having two phenolic hydroxyl groups, those conventionally known as raw materials for polycarbonate resins, for example, US Pat.
No. 3028365, No. 2999835, No. 3
No. 148172, No. 327601, No. 2991
No. 273, No. 327167, No. 3062781
No. 2,970131 or No. 2999846, German Patent Publication No. 1570703, No. 2
Nos. 063050, 2063052 or 221956, or French Patent 156.
No. 1518 can be used.

Some examples are hydroquinone, resorcin, dihydroxydiphenol, bis (hydroxyphenyl) alkane, bis (hydroxyphenyl) cycloalkane, bis (hydroxyphenyl) sulfide, bis (hydroxyphenyl) ether, bis (hydroxyphenyl) ether, Phenyl) ketone, bis (hydroxyphenyl) sulfone, bis (hydroxyphenyl) sulfoxide, bis (hydroxyphenyl) dialkylbenzene, and derivatives thereof having an alkyl or halogen substituent in the nucleus. Of these, preferred are 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) ) Cyclohexane and 1,1-bis (4-
(Hydroxyphenyl) -3,3,5-trimethylcyclohexane.

It is also possible to use a small amount of a branching agent having three or more functional groups with an aromatic compound having two phenolic hydroxyl groups. Such branching agents are known and include, for example, 2,4-bis (4'-hydroxyphenylisopropyl) phenol, 2,6-bis (2'-hydroxy-5'-methylbenzyl) -4-methylphenol, -(4-hydroxyphenyl) -2- (2,4-
Dihydroxyphenyl) propane, 1,4-bis (4,
4'-dihydroxytriphenylmethyl) benzene,
2,4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride, bis (4'-hydroxyphenyl) -2-oxo-2,3-dihydroxyindole, 3,3-bis (4-hydroxy-3-methylphenyl)- 2-oxo-2,3-dihydroindole and the like. Among them, those having three or more phenolic hydroxyl groups are preferred. The amount of the branching agent used varies depending on the desired degree of branching, but is usually used in an amount of 0.05 to 2 mol% based on the aromatic compound having two phenolic hydroxyl groups. Care must be taken when using a branching agent because the viscosity average molecular weight (Mv) tends to increase.

The oligomer used as a starting material has a viscosity average molecular weight Mv of 5,000 or less, preferably 3 or less.
000, more preferably 2,000 or less. The preferred molecular weight distribution is such that the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 2.2 or less (measured by gel permeation chromatography: in terms of polystyrene), and the viscosity average Molecular weight (M
v) and the number average molecular weight (M
n ') is 1.40 or less (Mv / Mn').
Preferably, (Mw / Mn) is 2 or less, and (Mv / M
n ') is 1.3 or less.

Such oligomers having a narrow molecular weight distribution can be obtained most skillfully when phosgenation is carried out by a continuous method, which corresponds to an environment in which a plurality of reactions having different reaction rates can proceed simultaneously. In this case, the reaction is carried out by mixing an aqueous solution prepared by dissolving an aromatic compound having two phenolic hydroxyl groups and caustic soda in water, and an inert organic solvent to prepare an emulsion, and adding phosgene thereto. It is supplied and reacted to produce an oligomer. The molar ratio of the aromatic compound having two phenolic hydroxyl groups to the caustic soda in the aqueous solution is usually from 1: 1.8 to 3.5, preferably from 1: 2.0 to 3.2. It is preferable to add a small amount of a reducing agent such as hydrosulfite to the aqueous solution. The ratio (volume ratio) of the organic phase to the aqueous phase is 0.1.
2 to 1.0 is preferred.

As the inert organic solvent, one that dissolves phosgene as a raw material and oligomers and polycarbonate resins formed by the reaction under the reaction conditions, but does not mutually dissolve in water is used. Representative inert organic solvents include aliphatic hydrocarbons such as hexane and n-heptane, methylene chloride, chloroform, carbon tetrachloride,
Chlorinated aliphatic hydrocarbons such as dichloroethane, trichloroethane, tetrachloroethane, dichloropropane and 1,2-dichloroethylene, aromatic hydrocarbons such as benzene, toluene and xylene, chlorobenzene, o
-Chlorinated aromatic hydrocarbons such as dichlorobenzene and chlorotoluene, and substituted aromatic hydrocarbons such as nitrobenzene and acetophenone. Among them, chlorinated hydrocarbons such as methylene chloride or chlorobenzene are preferably used. The amount of the oligomer used may be any amount that dissolves the oligomer to be produced, but is usually used such that the concentration of the produced oligomer solution is 10 to 40% by weight, preferably 15 to 30% by weight. These inert organic solvents can be used alone or as a mixture with other solvents.

The oligomer formation reaction is carried out at a temperature of 80 ° C. or lower, preferably 70 ° C. or lower. If the reaction temperature is too high, the side reaction increases and the phosgene specific unit decreases. Conversely, a low reaction temperature is advantageous in terms of reaction control, but the reaction is a large exothermic reaction, so the lower the temperature of the reaction system, the higher the cost of maintaining this temperature. Therefore, in consideration of these points, the reaction is most preferably performed at 10 to 65 ° C.

The oligomer used is one obtained by continuously reacting an aromatic compound having two phenolic hydroxyl groups with phosgene in the presence of water and an organic solvent by an interfacial polycondensation method. Is preferred. When reacted with phosgene in a batch system, the alkalinity changes with the progress of the reaction, and the degree of condensation also changes.At this stage, the oligomer already has a distribution to some extent, and this distribution is the same as the distribution of the polycarbonate polymer. You'll be dragging to the last stage you get. On the other hand, in the case of the continuous method, the obtained oligomer is always placed in the same environment and has a constant molecular weight at that stage, but there is no distribution like the batch method,
It can be said that favorable conditions have been established for the subsequent reactions.

The oligomer produced as described above is then subjected to interfacial polycondensation in the absence of a terminal stopper and in the presence of a specific amine catalyst to obtain a polycarbonate resin. The present invention is characterized by a combination in which the specific polycarbonate oligomer is polycondensed under specific conditions, whereby a polycarbonate resin having an extremely narrow molecular weight distribution and a monodisperse molecular weight distribution can be obtained. .

As a property required for the polycondensation catalyst for obtaining the polycarbonate resin intended in the present invention, an amine having a pKa value of the hydrochloride of 10 or less, preferably 7 or less, more preferably 5.5 or less is used. That is. That is, by using an amine catalyst having a weak basicity, a nucleophilic substitution reaction can be preferentially caused only from the other ionized terminal (phenylene-ONa terminal) without ionizing the chloroformate molecular terminal. . The reaction mechanism is different from that of condensation polymerization when producing conventional polycarbonate resin.
Since the reaction proceeds only by a single reaction, a polycarbonate having a molecular weight distribution according to the Poisson distribution is obtained as a result.

Further, the polycarbonate resin of the present invention is produced by an interfacial polycondensation reaction in which an aqueous phase and an organic phase are present as described later. In this interfacial polycondensation reaction, since the reaction proceeds by a nucleophilic substitution reaction only from the ionized end, the reaction is inevitably a sequential reaction that can only produce growth commensurate with the interface area per volume. The reached molecular weight is also large, and at the stage when the condensed species has disappeared, the chloroformate molecular terminal is hydrolyzed by NaOH in the aqueous phase, and the molecular weight extension stops as an OH terminal. In the case where the interfacial area per volume is small, as a side reaction, a chloroformate terminal which is a molecular terminal for the growth reaction is an N
It undergoes a hydrolysis reaction by aOH, and as a result, it becomes a state in which it cannot grow to a molecular weight higher than that, that is, a molecular weight controlled by an interfacial area. Behind such a reaction,
The growth reaction proceeds at a much faster rate than the hydrolysis reaction.

In the interfacial polycondensation reaction, the appropriate range of the pKa value of the amine catalyst used varies depending on what kind of solvent is used as the organic phase, and it is important to consider the balance with the solubility of the produced polymer. become. For example, unlike methylene chloride, when a non-polar solvent such as carbon tetrachloride is used, the solubility of the resulting polycarbonate is slightly inferior, but the molecular terminals tend to be less ionizable, so even amines having a relatively high basicity can be used. It is possible to maintain a state in which ions are not dissociated. In this case, a slightly higher amine can be used with a pKa value.

There is no such reaction imbalance in the conventional condensation polymerization that occurs during the production of a polycarbonate resin. In the conventional polycondensation, a catalyst having a high pKa value is used, and the chloroformate terminal is also activated in an ion-like manner by the catalyst having a high pKa value, and the reaction activity is almost comparable to the ionized phenylene-ONa terminal. At both molecular terminals, a condensate having a general molecular weight distribution according to Flory's most probable distribution can be obtained, and at the same time, in the absence of a terminal terminator, it becomes an ultrahigh molecular weight product .

It is preferable to use a salt of a nitrogen-containing heterocyclic compound as the amine catalyst satisfying the above conditions in the present invention. For example, pyridine, quinoline, isoquinoline, picoline, acridine, pyrazine, pyridazine, pyrimidine, 2,4,6-trimethyltriazine and the like may be substituted with an alkyl group, an alkoxy group, a halogen atom, etc. A salt of a compound having a saturated nitrogen-containing six-membered ring is used. Further, salts of compounds having an unsaturated nitrogen-containing five-membered ring such as phenothiazine, 2-methylimidazole, benzimidazole, benzotriazole, benzothiazole and the like are also used. Among these nitrogen-containing heterocyclic compounds, it is preferable to use pyridine, quinoline, picoline, imidazoles, pyrazoles, triazoles and the like.

The amount of these catalysts to be added is 0.001 to 0.002 relative to the raw material of the dihydroxy compound having two hydroxyl groups.
1 mol% is preferred. Since the amount of the catalyst is originally required only in an amount corresponding to the droplet boundary area, in a state where a constant boundary area is given, 0.01 to 0.1 mol%, preferably 0.02 to 0.1 mol% is used.
It is about 0.05 mol%. These nitrogen-containing heterocyclic compounds are used in a salt form such as a hydrochloride, a sulfate, a nitrate, and a hydrobromide. In a reaction system, a dissociation equilibrium between a free base form and a salt form is obtained. It is thought that there is.

After completion of the reaction between the dihydroxy compound and phosgene, these catalysts have an Mv of 5,000 or less, especially Mv3.
It is preferable to add at any stage after obtaining the oligomer of 000 or less. Before the oligomerization reaction,
Alternatively, addition during the oligomerization reaction is possible, but it tends to be difficult to obtain an oligomer having a narrow molecular weight distribution.

Usually, the reaction mixture obtained in the above oligomer production step is separated into an aqueous phase and an organic phase in which the oligomer is dissolved.
Inert organic solvents are added as needed to give a weight percent. Next, a caustic alkali such as a caustic soda aqueous solution is newly added to the oligomer solution, and the above-mentioned catalyst is added to carry out interfacial polycondensation.

In this case, the ratio of the aqueous phase to the organic phase is usually set to the ratio of the aqueous phase / oil phase (volume ratio) so that the aqueous dispersion phase can be maintained in the oil phase which becomes the continuous phase in the interfacial polycondensation reaction. 0.0
It is adjusted to about 5 to 2, preferably about 0.1 to 1.5, and most preferably about 0.5 to 1.2. If water is low,
Although there is no problem in maintaining the water-dispersed phase, heat generation due to polycondensation makes temperature control difficult, which is not preferable. On the other hand, if the amount of water is too large, it becomes difficult to maintain the water-dispersed phase at the time of stirring of the polycondensation, and there is a possibility that the water is transferred to the oil-dispersed phase. Once the phase transitions to the oil dispersion phase, a large interfacial area cannot be maintained and the molecular weight extension is not maintained, which is not preferable.

The temperature of the interfacial polycondensation reaction varies depending on the organic solvent used.
Done in From the viewpoint of controlling the molecular weight, the lower the temperature, the better. When the temperature is controlled to 20 ° C. or lower, more preferably 10 ° C. or lower, the molecular weight can be easily adjusted. As the temperature increases, a part of the chloroformate terminal, which has been controlled so as not to be ionized, starts to be partially ionized, and a phenomenon occurs in which a monodispersed molecular weight distribution is not obtained. There is no problem because the temperature is too low, but the temperature can be controlled as long as the aqueous phase (alkaline aqueous solution) does not freeze and a temperature of about 10 ° C. or less is sufficient.

After the completion of the polymerization, the organic phase was adjusted to have a chloroformate group content of the polycarbonate resin of 0.1 μeq / g.
Wash with an aqueous solution of caustic soda until the following, then neutralize the alkali by washing with an aqueous acid solution to remove the catalyst, and further wash with water to completely remove the electrolyte. Finally, the organic solvent is removed from the organic phase by evaporating to obtain a polycarbonate resin.

The viscosity average molecular weight (Mv) of the polycarbonate resin thus obtained is usually from 8,000 to 10
It is about 0000. If the molecular weight is too low, the impact resistance of the polycarbonate resin will be poor, and if the molecular weight is too high, the melt fluidity will be poor. The viscosity average molecular weight is 1
000 to 70,000, especially 12,000 to 50,
000 is preferred. This polycarbonate resin has an extremely narrow molecular weight distribution and low volatility as it is produced by the interfacial polycondensation reaction, that is, without performing a treatment for adjusting the molecular weight distribution such as fractional precipitation or extraction and removal of low molecular weight components. Sex can be achieved.

The polycarbonate resin obtained as described above can be used at any stage of the oligomer formation reaction and the polymerization reaction from the oligomer to the polycarbonate resin.
Since the reaction is carried out without using a terminal stopper, the molecular terminal is a hydroxyl group. If a polycarbonate resin having a molecular terminal sealed with a long-chain alkyl group or the like is desired, the above-obtained polycarbonate resin is then reacted with a long-chain alcohol, a long-chain carboxylic acid, or a reactive derivative thereof. Thereby, it is possible to obtain a polycarbonate resin having a terminal capped to a desired degree. However, this molecular terminal modification reaction is limited only after the polymerization has been completed and a monodispersed polycarbonate resin is once generated. When a molecule having a terminated molecular terminal is present during the polymerization reaction, only the reactivity of the molecule is inferior, and as a result, only a product having a wide molecular weight distribution with a tail in a low molecular weight region can be obtained.

The polycarbonate resin of the present invention produced by the above method is usually used in a ratio (Mw) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography.
/ Mn) is 2.2 or less, and the ratio (Mv / Mn ') of the viscosity average molecular weight (Mv) calculated from the following formula to the number average molecular weight (Mn') calculated from the number of molecular terminals is 1: .4
0 or less.

Ηsp / C = [η] × (1 + 0.28ηsp) [η] = 1.23 × 10 ⁻⁴ × Mv ^0.83

Where ηsp is the specific viscosity of the methylene chloride solution of the polycarbonate resin measured at 20 ° C., and C is the concentration of the methylene chloride solution. The methylene chloride solution has a polycarbonate resin concentration of 0.6 g.
/ Dl. )

The polycarbonate resin according to the method of the present invention preferably has a Mw / Mn of 2.0 or less, particularly 1.8 or less. Mv / Mn 'is 1.30 or less, particularly 1.
It is preferably 20 or less. Mw / Mn and Mv / M
Each of n 'is an index indicating the width of the molecular weight distribution, and a smaller value means that the molecular weight distribution is narrower.
As described above, a number of methods for producing a polycarbonate resin having a narrow molecular weight distribution have been conventionally proposed.However, the polycarbonate resin according to the present invention is different from those according to the conventional production methods and has a remarkably narrow molecular weight distribution. have. As a result, there is no substance corresponding to the oligomer volatilized at the time of melt molding, and excellent properties are exhibited as low sublimability at the time of melt molding.

In this method for producing a polycarbonate resin, the molecular weight can be adjusted by, for example, adjusting the amount of the polycondensation catalyst used and the interfacial area during interfacial polycondensation. In order to change the droplet boundary area in interfacial polycondensation, the load power by stirring is usually selected from the range of about 1 to 100 kw / m ³ . In this range, the viscosity average molecular weight Mv is 5,000 to 5,000.
50,000 can be manufactured stably.

Here, in the batch reaction, the load power due to the stirring is defined as [P / V] obtained by dividing the required power (P) by the volume (V) of the interfacial polycondensation reaction solution. Is defined as the product of the product of the required power (P) and the residence time (θT) in the reactor divided by the flow rate of the reaction liquid (q) [P × θT / q].
If the load power due to stirring is too large, the molecular weight becomes too large, and the solution viscosity becomes extremely high, making stirring difficult.
On the other hand, if it is too low, only a low molecular weight which is unsuitable for polycarbonate is produced, which is not preferable. Therefore,
A preferable range of the load power is 5 to 50 kw / m ^3.
It is about. More preferably, it is about 7 to 20 kw / m ³ .

Since the load power P / V by stirring in the batch reaction is defined by the following equation, the stirring rotation speed n can be determined based on this. The same applies to a continuous reaction if the residence time (θT) and the flow rate (q) of the reaction solution are used instead of the volume (V) of the reaction solution.

P / V = (Np × n ³ × d ⁵ × ρ) / V

Here, P: required power (kw) V: volume of reaction liquid (m ³ ) Np: mechanical constant n: stirring speed (rps) d: blade diameter of stirring blade (m) ρ: density of reaction liquid (kg / m ³⁾

The polycarbonate resin produced by the method of the present invention can be processed into various molded products by injection molding, extrusion molding or the like, similarly to the conventional polycarbonate resin. Such processed products include films, yarns,
Examples include materials such as plates, parts such as lighting equipment and optical equipment, and substrates for optical disks and magneto-optical disks. In the production of these molded products, a stabilizer, a mold release agent, a flame retardant, an antistatic agent, a filler, a fiber, an impact strength modifier and the like may be added to the polycarbonate resin by a conventional method.

[0048]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples. In the following examples, gel permeation chromatography, quantitative determination of terminal groups and evaluation of melt fluidity were performed as follows. (1) Gel permeation chromatography (GP
C); Apparatus; Tosoh Corporation product, HLC-8020 column; TSK 5000HL as filler
X, 4000HLX, 3000HLX and 2000HL
Four columns (diameter: 7.8 mmφ, length: 300 mm) filled with X (both manufactured by Tosoh Corporation) were used.

Detector; Refractometer Eluent; Tetrahydrofuran calibration curve; Standard polystyrene (molecular weight;
761 (Mw / Mn ≦ 1.14), 2000 (Mw / M
n ≦ 1.20), 4000 (Mw / Mn ≦ 1.06),
9000 (Mw / Mn ≦ 1.04), 17500 (Mw
/Mn≦1.03), 50,000 (Mw / Mn ≦ 1.0)
3) 233,000 (Mw / Mn ≦ 1.05), 600
000 (Mw / Mn ≦ 1.05) and 900,000 (M
w / Mn ≦ 1.05).

Operation: Mw and Mn were determined in terms of polystyrene from the chart obtained by detecting the difference in refractive index, and Mw / Mn was calculated. The baseline at this time is
When the apparatus was completely stable, the base before the rising of the high molecular weight was faithfully extended as it was, and the calculation was performed by connecting the point of returning to the original baseline on the low molecular weight side. In addition, the above-mentioned standard polystyrene was measured, and it was confirmed that all were within the standard.

(2) Quantification of terminal groups: The terminals of the polycarbonate resin produced without using a terminal stopper and the remaining terminals not terminated by the terminator are all OH groups. The terminal OH group was quantified by coloring with titanium tetrachloride under acetic acid acidity and measuring the absorbance at a wavelength of 480 nm. The number average molecular weight (Mn ') was calculated as follows.

Mn ′ = 10 ⁶ / (number of terminal groups (μeq /
g) x 1/2)

When a terminal stopper is used in the polymerization, all the terminal stoppers are bonded to the terminals.
The total of the number of terminal OH groups obtained in the above measurement and the number of terminated terminal groups calculated from the amount of the terminator added was defined as the number of terminal groups.
In addition, the polycarbonate resin polymerized in the presence of the terminating agent by a preliminary experiment is subjected to alkaline hydrolysis, the amount of the bound terminating agent is quantified, and the used terminating agent is all bound to the molecular terminal. It was confirmed.

(3) Decomposition and measurement of volatiles 20 g of polycarbonate pellets were placed under vacuum (1 mmH
g) Seal the glass, and only the pellet part is 20 at 350 ° C.
Heated for a minute. The air-cooled glass gas phase (150
(C-50C) only dissolved in tetrahydrofuran (THF). The solution was measured by liquid chromatography (LC) (conditions: THF / water (1
/ 1) Gradient from solvent to THF 100%, detector: UV 270 nm, measurement model: Shimadzu LC-9A, manufactured by Shimadzu Corporation. Compounds developed by the LC were identified by LC-MS. Among the identified compounds, among the linear oligomers sandwiching bisphenol A (BPA), a highly sublimable monomer (PBP of the following formula), a PB terminated only at one end (the following formula) and a terminator The amounts of the condensed C-PTBP (the following formula) were compared. The degree of influence of each oligomer differs depending on the molding temperature, and each oligomer has sublimability and contaminates a mold and a stamper.

[0055]

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[0056]

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[0057]

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On the other hand, when the terminator is phenol, diphenyl carbonate (DPC) and phenyl-terminated P
B and PBP are targeted. This compound also shows sublimability,
It has been found that it adheres to molds and stampers during molding and affects products.

[0059]

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(In the above formulas, PhO- is a phenol residue, tBuPhO- is a t-butylphenol residue, and O-BPA-O is a bisphenol A residue.)

Examples 1 to 3 Bisphenol A was dissolved at 35 ° C. in an aqueous solution of caustic soda in which hydrosulfite was dissolved and then cooled to 25 ° C. and methylene chloride cooled to 5 ° C.
The mixture is continuously supplied to a stainless steel pipe having an inner diameter of 6 mm and mixed, and the mixture is emulsified by passing through a homomixer (a product of Tokushu Kika Co., Ltd., TK homomic line flow LF-500 type) to obtain an emulsion. A liquid was prepared. The feed rate to the pipe is 16.31 kg / h of bisphenol A, and caustic soda 5.
93 kg / h, water 101.1 kg / h, hydrosulfite 0.018 kg / h, and methylene chloride 68.0
kg / h.

The resulting emulsion was allowed to flow through a 6 mm inner diameter pipe and into a Teflon (registered trademark) pipe reactor having an inner diameter of 6 mm and a length of 34 m. Liquefied phosgene, which was simultaneously cooled to 0 ° C., was supplied to the pipe reactor at a rate of 7.5 kg / hour to cause a reaction to produce an oligomer. The flow rate in the pipe reactor is 1.7 m / sec. As phosgene, activated carbon (product of Taihei Chemical Co., Ltd .: product name: Yashikol S, true density: 2.50 cm) was placed in a cylindrical container having a diameter of 55 mm and a height of 500 mm.
1 g / ml, porosity 40%, specific surface area 1200 m ² /
g, pore volume 0.86 ml / g)
Purified phosgene cooled to -5 ° C was passed through at SV = 3.

In the pipe reactor, the temperature rose to 60 ° C., but was 35 ° C. at the outlet due to external cooling. The reaction mixture was separated by standing and separated into an aqueous phase and an oil phase. The chloroformate concentration of the obtained oligomer was 0.1.
49N, OH terminal concentration was 0.22N, oligomer concentration was 27%, and Mv was 1,000. 4 from the obtained oil phase
1 kg was fractionated and charged into a 200 liter inner volume reactor with a Faudler blade (stirring blade diameter: 0.25 m). Next, 25 kg of methylene chloride and 45 kg of water were added thereto, and the mixture was cooled to 3 ° C. while stirring under a nitrogen atmosphere.
And 5.82 kg of a 25% aqueous solution of caustic soda were added, and the stirring load power (rotational speed 5.
The polymerization reaction was carried out with stirring at 5 to 6.3 rps and a mechanical constant of Np = 5) to produce a polycarbonate resin.
At this time, the internal temperature of the polymerization rose to 11 ° C.

To the reaction mixture were added 50 kg of methylene chloride and 14 kg of water, and the mixture was stirred at room temperature for 20 minutes and allowed to stand to separate an aqueous phase and an organic phase. After adding 40 kg of 0.1 N hydrochloric acid to the organic phase and stirring for 15 minutes, the aqueous phase and the organic phase were separated by standing still. 40 kg of pure water in this organic phase
Was added, and the mixture was stirred for 15 minutes, then allowed to stand, and the washing operation of separating into an aqueous phase and an oil phase was repeated three times. As a result, chlorine ions were no longer detected in the aqueous phase, so the washing operation was stopped.
The methylene chloride is evaporated off from the organic phase with a kneader,
The obtained powder was dried to obtain a polycarbonate resin.
Table 1 shows the polymerization conditions and the physical properties of the obtained polycarbonate resin.

Example 4 340 g of the oligomer solution obtained in Example 1 was fractionated,
1 g of a homomixer (diameter of stirring blade: 0.029 m), 180 g of methylene chloride and 360 g of water were charged. After cooling to 3 ° C. while stirring under a nitrogen atmosphere, 40 g of a catalyst described in Table 1 and a 25% aqueous solution of caustic soda were added. For 60 minutes, the stirring load power (rotational speed 158 rps,
The polymerization reaction was carried out with stirring at a mechanical constant (Np = 0.8) to produce a polycarbonate resin. At this time, the internal temperature of the polymerization rose to 15 ° C. The subsequent washing (the amount used is proportional to the volume), pulverization, and drying operations were the same as those in Example 1.

Example 5 The amount of the nitrogen-containing catalyst used in Example 3 was 0.02 mol%.
Was reduced to 0.015 mol%, and the same operation as in Example 3 was performed. The results show that as shown in Table 1, the average molecular weight is increased and the molecular weight distribution is further sharpened.

Example 6 The solvent used for the oligomer solution of Example 3 was changed to carbon tetrachloride instead of methylene chloride, the oligomer concentration at the time of polycondensation was 1%, and 2-aminoethanol (pKa =
The same operation as in Example 3 was performed except that 9.52) was used. The results are shown in Table 1.

Comparative Example 1 In the step of forming an oligomer from bisphenol A and phosgene, the procedure of Example 1 was repeated except that para-t-butylphenol was used as a terminal stopper and triethylamine having a pKa of 10.72 was used as a catalyst. A polycarbonate resin was produced in exactly the same manner as in Example 2. Table 1 shows the polymerization conditions and the physical properties of the obtained polycarbonate resin.

Comparative Example 2 The oligomer obtained in Example 1 was used in the polycondensation stage in the presence of para-t-butylphenol, pKa = 10.
A polycarbonate resin was produced in exactly the same manner as in Example 2 except that triethylamine No. 72 was used as a catalyst. Table 1 shows the polymerization conditions and the physical properties of the obtained polycarbonate resin.

Comparative Example 3 In the step of forming an oligomer from bisphenol A and phosgene, no terminal stopper was present and pKa = 1.
The operation was carried out exactly as in Example 2, except that 0.72 of triethylamine was used as the catalyst. The viscosity rapidly increased from the middle of the polymerization, and the reaction was terminated in a state where the reactant was wound around the stirring blade. An analyzable polycarbonate resin could not be obtained.

Comparative Example 4 (Additional Examination of JP-A-56-129930) Pure water: 40 in a 1 L separable flask (with a jacket)
0 g, methylene chloride 600 ml, bisphenol A15
0.4 g and 0.6 g of 3-methylpyridazine were charged and the jacket temperature was set to 7 ° C. and the internal temperature was set to 15 ° C. while stirring with stirring load power (rotational speed 19 rps, mechanical constant Np = 5) shown in Table 1. And cooled. Thereafter, phosgene was added to 1.
At the same time as feeding at a flow rate of 8 g / min, 25% NaO
H was added to control the pH to 9. This condition was maintained for 30 minutes, after which the phosgene feed was stopped once and the pH was raised to 11. At this time, the temperature rose to 27 ° C. Phosgene was fed again at a flow rate of 1.8 g / min for 10 minutes while maintaining the pH at 11 while adding NaOH. After 10 minutes, the phosgene feed was stopped, the pH was raised to 13, and phosgene was again added to 1.8.
The pH was maintained at 13 while feeding at a flow rate of g / min.
Maintained for minutes. Thereafter, the addition of phosgene and NaOH was stopped, and the stirring was stopped. The reaction solution was a viscous emulsion. After dilution with methylene chloride, the solution was washed with acid, washed with water and washed with water, and the Mv of the dried product was 15,400. The GPC measurement result was Mw / Mn: 3.60. Various deposits such as linear dimers were observed on the inner surface of the flask.

Comparative Example 5 The oligomer solution passed through the pipe reactor was introduced into the next reaction tank (oligomerization tank) having a stirrer having an inner volume of 50 liters, and 1.23 kg / h of sodium hydroxide was added thereto. By stirring at 30 ° C. and oligomerizing, the unreacted sodium salt of bisphenol A (BPA-Na) present in the aqueous phase is completely consumed, and at the same time, the alkali in the aqueous phase is consumed, and After elongating the molecular weight, the aqueous phase and the oil phase were allowed to stand and separated to obtain a methylene chloride solution of the oligomer. At this time, the chloroformate concentration of the oligomer was 0.062 N, the OH group was 0.048 N,
The oligomer concentration was 26.5% and the Mv was 7000. The same operation as in Example 2 was performed except that the terminal stopper and the catalyst described in Table 1 were added to this oil phase. Mw / M is 2.6
It was 5.

Comparative Example 6 (Repeat of Example 4 in US Pat. No. 3,269,985) Bisphenol A-bischloroformate oligomer (Mv = 2000): 35 while stirring a mixture of 50 ml of pyridine and 2 ml of water in a 1 liter flask. A mixed solution of 200 ml of chlorobenzene in which 0.3 g was dissolved and 50 ml of pyridine was added dropwise. This reaction was slightly heated (40 ° C.) and cooled to room temperature to promote the dissolution of bischloroformate. The product was precipitated with isopropyl alcohol, filtered and dried. The molecular weight (Mv) of the obtained polycarbonate was 9,200, and Mw / Mn = 2.35.

Comparative Example 7 (Repeated test of Example 5 of US Pat. No. 3,437,639) 22.8 g of bisphenol A, 40 ml of dry pyridine,
The mixed solution of 100 ml of dry THF was stirred and set at 25 to 30 ° C. in a water bath. To this, phosgene 10.
0 g was added over 15 minutes. While stirring the mixture for 5 minutes, an additional 0.5 g of phosgene was added over 5 minutes. Thereafter, the mixture was further diluted with THF and passed with hydrochloric acid gas. The polycarbonate solution was precipitated by slowly adding the polymer solution into acetone with stirring. The molecular weight (Mv) of the obtained polycarbonate was 10800, M
w / Mn was 2.59.

Comparative Examples 6 and 7 are examples of solution polymerization using pyridine as a solvent. It is understood that a product having a sharp molecular weight distribution cannot be obtained only by using pyridine. Such a catalyst is used in interfacial polycondensation to produce a large difference in the reactivity of the molecular terminals, and can be produced only when a terminal stopper is not present at that time. With the conventional method as shown, the molecular weight distribution was broad.

[0076]

[Table 1]

[0077]

[Table 2]

[0078]

The polycarbonate resin obtained by the method of the present invention is remarkably different from the polycarbonate resin obtained by the conventional production method because a specific pKa value such as pyridine hydrochloride is used as an interfacial polycondensation catalyst. This is derived from the use of the amine compound of No. 1 and no use of a terminal stopper. In the past, as a method for producing a polycarbonate resin, there was also a method by solution polymerization using pyridine as a solvent (US Pat. Nos. 3,275,601 and 32,699).
No. 85, No. 3437639, No. 3804722 and No. 3428600). This polymerization method is intended for dissolving bisphenol as a raw material and for trapping hydrochloric acid generated by the reaction. Since a cyclic compound is used as a solvent, there is no effect of activating only one terminal at the time of condensation, and in each case, only those having a molecular weight distribution close to the most probable distribution can be obtained.

From these solution method techniques, the interfacial polycondensation method has become the mainstream of the polycarbonate resin production method, but triethylamine is a catalyst commonly used for the production of polycarbonate resin. When the oligomer is polymerized using only triethylamine as a catalyst, the polymerization reaction proceeds excessively in the absence of a terminal stopper, and a gel-like ultrahigh molecular weight polycarbonate resin is produced. Therefore, in the production of a conventional polycarbonate resin, the use of a terminal stopper was indispensable. However, when polymerization is carried out in the presence of a terminating agent, the end-capped molecules do not grow, so that the growth of the molecules varies, and the molecular weight distribution inevitably has a considerable width. . However, when a nitrogen-containing heterocyclic compound such as pyridine hydrochloride is used as a catalyst, the reaction can be easily controlled without the presence of a terminal blocking agent, and the growth of the molecules is uniform since the molecular terminals are not blocked. It is considered that the molecular weight distribution is inevitably narrowed.

Originally, such a polymer having a sharp molecular weight distribution cannot be obtained as long as the bifunctional monomers have the same reactivity, and all of them are ideal polymers according to Flory's theory and have Mw / Mn = 2.0. It just becomes. The mechanism by which such a polymer having a sharp molecular weight distribution can be obtained is an environment in which one end of a molecule has an extremely different reactivity from the other end, and the reaction can proceed only from one direction. This is considered to be due to the fact that the condensation reaction of the polycarbonate catalyzed by pyridine shown in Examples satisfies this condition. That is, a weakly basic catalyst such as pyridine cannot be activated until the chloroformate terminal at the molecular terminal is ionized, and the reaction proceeds only from the ionized phenylene-ONa terminal. Accordingly, the obtained polymer is close to monodisperse, but when there is no reaction partner, the hydrolysis of the chloroformate terminal which originally proceeds at the same time progresses and stops as an OH terminal.

Therefore, when the interfacial area per unit volume of interfacial polycondensation is large, the monomer supply is abundant, so that the molecular weight is increased. On the other hand, when the interfacial area per unit volume is small,
The hydrolysis reaction at the terminal of the chloroformate molecule takes precedence over the condensation reaction, resulting in a state where it can grow only to a certain molecular weight. As can be seen from Table 1 above, the molecular weight (Mv) increases according to the stirring rotation speed (emulsion boundary area) during the interfacial polycondensation reaction.

[0082]

According to the method of the present invention, a polycarbonate resin having a molecular weight distribution close to monodispersion can be provided. In particular, since the polycarbonate resin obtained by the present invention has an extremely narrow and sharp molecular weight distribution, the amount of low-molecular-weight oligomers is extremely small, and there is no volatile matter derived from the oligomers during heat molding. It is excellent.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshimitsu Inoue 1-1 Kurosaki Castle Stone, Yawatanishi-ku, Kitakyushu City, Fukuoka Prefecture Inside the Kurosaki Office of Mitsubishi Chemical Corporation (72) Inventor Kenji Tsuruhara 1st Kurosaki Castle Stone, Yawata-Nishi-ku, Kitakyushu City, Fukuoka Prefecture No. 1 Mitsubishi Chemical Corporation Kurosaki Office F-term (reference) 4J029 AA09 AD01 BB04A BB05A BB12A BB13A BB13B BD09A BD09C BE04 BF13 BH02 DB07 DB11 DB13 FC33 FC35 HA01 HC01 JC221 JC261 JC281 KC01 KE11

Claims (6)

[Claims] 1. A polycarbonate oligomer obtained by reacting a carbonate raw material with a dihydroxy compound, having a viscosity average molecular weight (Mv) of 5 as calculated by the following formula:
Producing a polycarbonate resin, wherein an interfacial polycondensation is carried out using an oligomer having a basicity of not more than 000 as a starting material and a pKa as a hydrochloride salt of 10 or less in the absence of a terminal terminator as a catalyst. Law. ηsp / C = [η] × (1 + 0.28ηsp) [η] = 1.23 × 10 ⁻⁴ × Mv ^0.83 (wherein, ηsp is a specific viscosity measured at 20 ° C. of a methylene chloride solution of polycarbonate; Is the concentration of this methylene chloride solution. A methylene chloride solution having a polycarbonate concentration of 0.6 g / dl is used.) 2. A weight average molecular weight (Mw) and a number average molecular weight (Mn) of a polycarbonate resin (measured by gel permeation chromatography: in terms of polystyrene).
2. The method for producing a polycarbonate resin according to claim 1, wherein the ratio (Mw / Mn) of the polycarbonate resin is 2.2 or less. 3. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the polycarbonate oligomer as a starting material is 2.2 or less, and the viscosity average molecular weight (Mv) and the molecular terminal The polycarbonate according to claim 1 or 2, wherein the ratio (Mv / Mn ') to the number average molecular weight (Mn') calculated from the number is 1.40 or less and the molecular terminal is not blocked. Method of manufacturing resin. 4. A polycarbonate oligomer as a starting material is produced by an interfacial polycondensation method in the presence of water and an organic solvent.
The method for producing a polycarbonate resin according to any one of claims 1 to 3, wherein the polycarbonate resin is obtained by continuously reacting an aromatic compound having a divalent phenolic hydroxyl group with phosgene. 5. The amount of the amine catalyst added is from 0.001 to 1 mol% based on the dihydroxy compound.
A method for producing the polycarbonate resin according to any one of the preceding claims. 6. The polycarbonate resin according to claim 1, wherein the stirring is performed with a stirring load power of 1 to 100 kW / m ^{3 in} order to change the droplet boundary area in the interfacial polycondensation. Manufacturing method.