JPH0987378A - Production of polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a process for producing a polycarbonate which does not exhibit coloration and of which all the terminal hydroxyl groups or a part of them have been blocked by using a specific terminal-blocking agent in a melt polymn. process (transesterification). SOLUTION: In a process for producing a polycarbonate by subjecting an arom. dihydroxy compd. and a carbonic diester compd. to transesterification under melting, a ketene compd. represented by formula I (wherein R1 and R2 are each a 1-40C hydrocarbon group) or formula II (wherein R3 is a 2-20C hydrocarbon group) or a ketene dimer represented by formula III is used as a terminal-blocking agent. Precursors for those ketene compds. can also be used. Examples of the precursor are a disubstd. malonic anhydride, a disubstd. acylal, and an α-diketone. The blocking agent is added pref. when the polymn. reaches a desired step when the intrinsic viscosity of a resultant polymer is relatively high, usually in an amt. of 0.1-10mol per mol of the terminal hydroxyl group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polycarbonate by a melt transesterification method, more specifically, an aromatic compound in which some or all of the phenolic hydroxyl groups of the polymer are blocked (capped). The present invention relates to a method for producing polycarbonate.

[0002]

2. Description of the Related Art Polycarbonate is widely used because of its excellent mechanical properties such as impact resistance, heat resistance and transparency. As a method for producing such a polycarbonate, a method in which phosgene is directly reacted with an aromatic dihydroxy compound such as bisphenol A (interfacial polymerization method), or an aromatic dihydroxy compound such as bisphenol A and a diallyl carbonate such as diphenyl carbonate are melted A method of performing a transesterification reaction in the state (melt polymerization method) and the like are known.

Among such production methods, a method of transesterifying an aromatic dihydroxy compound and diallyl carbonate (melt polymerization method) is a halogen compound such as toxic phosgene or methylene chloride as compared with the interfacial polymerization method. It is considered to be promising in the future because it has an advantage that it can be produced at low cost without the problem of using as a solvent.

In the production of a polycarbonate by this melt polymerization method, various end-capping agents are used in order to improve the stability and quality of the polymer such as hue, heat resistance and hydrolysis resistance of the resulting polycarbonate. Encapsulation of the hydrated hydroxyl end groups has been investigated.

Regarding such an end-capping agent, JP-A-2-
In Japanese Patent No. 175723, an aromatic hydroxy compound and a carbonic acid diester are melt-polymerized in the presence of a specific catalyst, and a hydroxyl group end of a polycarbonate obtained is a specific compound (here, phenols having 10 to 40 carbon atoms and carbon number 1).
3 to 16 carbonic acid diesters are exemplified).

However, when the phenols described in the above publication are used as the end capping agent, a considerable amount of time is required for end capping, which is not preferable. Further, when the phenols described in the above publication are used as the end-capping agent in the latter stage of the transesterification reaction, there is a problem that the concentration of the phenols in the reaction system increases and the molecular weight of the polymer decreases.

Further, when the carbonic acid diesters described in the above publication are used as an end-capping agent, if the carbonic acid diesters are added in the initial stage of the transesterification reaction, the reaction rate decreases due to the decrease in the terminal hydroxyl group concentration in the reaction system. Causes productivity to deteriorate.

On the other hand, when the carbonic acid diesters are added in the latter stage of the transesterification reaction, the carbonic acid diesters have a low reactivity and the terminals are not rapidly blocked. Further, the carbonic acid diesters disclosed in the above publications are
Many of them have a higher molecular weight than the carbonic acid diesters used as polymer raw materials, and unreacted carbonic acid diesters and by-produced high molecular weight phenols are likely to remain in the system as residual monomers, resulting in polymer quality. There is a problem of having an adverse effect.

In Japanese Patent Laid-Open No. 6-157739, at least two reactors are used in series to melt-polymerize an aromatic hydroxy compound and a carbonic acid diester, and a specific end-capping agent (here, carbon number 17 is used). To 50 carbonic acid diesters, 13 to 16 carbonic acid diesters, 2 to 5 carbon atoms
0 epoxy compounds and C 10-40 phenols are exemplified) to at least one reactor in which the intrinsic viscosity of the polymer at the reactor inlet is 0.20 dl / g or more. ing.

However, in these end-capping agents,
As in the case of the above-mentioned JP-A-2-175723, there is a drawback that the reactivity of the carbonic acid diester is low and the end capping is not performed promptly. Therefore, it is necessary to add a large amount of the agent in order to rapidly and sufficiently block the hydroxyl group end using these endcapping agents, but addition of a large amount of the agent causes a decrease in the molecular weight of the polymer. It happens and is not preferable.

For the above reasons, it is desired to use a compound having a higher reactivity than the above-mentioned carbonic acid diester and phenols as the polymer end-capping agent.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a method for producing a polycarbonate by a melt polymerization method (transesterification method) for producing a polymer in which some or all of the phenolic hydroxyl groups of the polymer are blocked. The purpose is to do. Further, the present invention, by the melt polymerization method, it is possible to produce a polycarbonate having no coloration and having a part or all of the terminal hydroxyl groups of the polymer blocked, and at the time of molding, polymerization or polymerization, in the molding apparatus, coloring, insolubilization. Another object of the present invention is to provide a method for producing a polycarbonate in which the generation of foreign matter and the decrease in molecular weight are suppressed to a low level.

[0013]

According to the present invention, a specific ketene compound is used as an end-capping agent for a polymer when a polycarbonate is produced by transesterifying an aromatic dihydroxy compound and a carbonic acid diester compound under melting. This solves the above-mentioned problems.

In the present invention, the ketene compound used as the terminal blocking agent is at least one of ketene compounds represented by the following general formula (I) or general formula (II).

[0015]

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[In the formulas (I) and (II), R ¹ and R ² are the same or different and are hydrocarbon groups having 1 to 40 carbon atoms (for example, methyl group, ethyl group, propyl group, n-butyl group, alkyl groups such as t-butyl group and nonyl group, allyl groups such as phenyl group, tolyl group, cumyl group and naphthyl group),
R ³ represents a hydrocarbon group having 2 to 20 carbon atoms (for example, an alkylidene group such as an ethylene group, a propylene group, a pentylene group). ]

Further, in the present invention, a ketene dimer can be used as the terminal blocking agent. This ketene dimer has the following general formula (III)

[0018]

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[In the formula (III), R ¹ and R ² are the above formula (I)
Synonymous with].

The ketene compound used as the terminal blocking agent is dimethyl ketene, diethyl ketene, dipropyl ketene, di-n-butyl ketene, di-t-butyl ketene,
Dialkyl ketene such as dinonyl ketene, n-butyl methyl ketene, t-butyl methyl ketene, ethyl-t-butyl ketene and t-butyl nonyl ketene, diallyl ketene such as diphenyl ketene, ditolyl ketene, dicumyl ketene, phenyl tolyl ketene and phenyl cumyl ketene. , Alkyl butyl ketene such as n-butyl phenyl ketene, t-butyl phenyl ketene and nonyl phenyl ketene, and cycloalkylidene ketene such as cyclopropylidene ketene, cyclopentylidene ketene and cyclohexylidene ketene.

Of these, diphenylketene is particularly preferably used. These ketene compounds can be used alone or in combination of two or more.

Specific examples of the ketene dimer used as the end-capping agent include dimers of the above ketene compounds. That is, dimethyl ketene 2
Dimer, diethyl ketene dimer, dipropyl ketene dimer, di-n-butyl ketene dimer, di-t-butyl ketene dimer, dinonyl ketene dimer, n-butyl methyl ketene dimer, t- Butyl methyl ketene dimer, ethyl-
Dialkylketene dimers such as t-butylketene dimer and t-butylnonylketene dimer, diphenylketene dimer, ditolylketene dimer, dicumylketene dimer, phenyltolylketene dimer, phenylcumyl Diallyl ketene dimer such as ketene dimer, n-butylphenyl ketene dimer, t-butylphenyl ketene dimer, alkylallyl ketene dimer such as nonylphenyl ketene dimer, cyclopropylidene ketene Examples thereof include cycloalkylidene ketene dimers such as dimers, cyclopentylidene ketene dimers, and cyclohexylidene ketene dimers.

Of these, diphenyl ketene dimer is particularly preferably used. These ketene dimers can be used alone or in combination of two or more. Further, the ketene and the ketene dimer may be used in combination.

In the present invention, the precursor of the above ketene compound can also be used as the terminal blocking agent. Here, the precursor of a ketene compound means a compound which produces ketene by thermal decomposition.

In the present invention, the precursor of the ketene compound used as the terminal blocking agent is a disubstituted malonic acid anhydride represented by the general formula (IV).

[0026]

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Or a 2-substituted acylal represented by the general formula (V)

[0028]

[Chemical 6]

Or an α-diazoketone represented by the general formula (VI)

[0030]

[Chemical 7]

The compounds represented by [in the above formulas, R ¹ and R ² are the same as those described above] are included.

Specific examples of the 2-substituted malonic anhydride include:
Dialkylmalonic anhydrides such as dimethylmalonic anhydride, diethylmalonic anhydride, dipropylmalonic anhydride, di-n-butylmalonic anhydride, di-t-butylmalonic anhydride and dinonylmalonic anhydride And diarylmalonic acid anhydrides such as diphenylmalonic acid anhydride, ditolylmalonic acid anhydride and dicumylmalonic acid anhydride.

Of these, di-n-butylmalonic acid anhydride and diphenylmalonic acid anhydride are particularly preferably used. These malonic anhydrides can be used alone or in combination of two or more. Also, the above ketene 2
You may use it in combination with a monomer and ketene.

Specific examples of the 2-substituted acylal include dimethyl ketene acylal, diethyl ketene acylal, dipropyl ketene acylal, di-n-butyl ketene acylal, di-t-butyl ketene acylal, and dinonyl ketene acyl. Dialkyl ketene acylals such as lar,
Examples thereof include diallyl ketene acylals such as diphenyl ketene acylal, ditolyl ketene acylal, and dicumyl ketene acylal.

Of these, diphenyl ketene acylal and di-n-butyl ketene acylal are particularly preferably used. These 2-substituted acylals may be used alone or
It can be used in combination of more than one kind. Further, it may be used in combination with the malonic anhydride, ketene dimer or ketene.

Specific examples of α-diazoketones include α-
Diazoethyl methyl ketone, α-diazobutyl propyl ketone, α-diazodibutyl ketone, α-diazobenzyl phenyl ketone, α-diazobenzyl cumyl ketone and the like can be mentioned. Of these, α-diazobenzyl phenyl ketone is particularly preferable. Used. These α-diazoketones can be used alone or in combination of two or more. Further, it may be used in combination with the malonic anhydride, disubstituted acylal, ketene dimer or ketene.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, with respect to the timing of adding the above-mentioned end-capping agent, when the desired polymerization step in which the intrinsic viscosity of the polymer is relatively high is reached, for example, the polycondensation reaction is substantially completed. At this stage, it is preferable to block the ends of the polymer by adding an end capping agent and reacting. As a result, the polymerization of the polycarbonate proceeds rapidly and sufficiently from the stage where the intrinsic viscosity is relatively low to the desired degree of polymerization, and at the time when the desired degree of polymerization is reached, an agent is added to provide a sealing effect. By doing so, the effect of improving the polymer quality such as hue, heat resistance and hydrolysis resistance can be imparted.

In the present invention, the reactor to which the end-capping agent is supplied is not particularly limited, but is preferably added to the reactor in which the polymerization of the polycarbonate has proceeded rapidly and sufficiently and the desired degree of polymerization has been reached. To do.

The method of adding the terminal blocking agent is not particularly limited, and it may be added as a solid or liquid as it is, or after being dissolved in various solvents. Further, the end-capping agent may be added in a predetermined amount all at once, or may be added in several divided portions.

Regarding the addition amount of the terminal blocking agent in the present invention, the terminal blocking agent is added to the terminal hydroxyl group of the polymer in the range of 0.
1 to 10 times mol, preferably 0.3 to 5 times mol, and more preferably 0.5 to 2 times mol can be added. Here, the number of moles of terminal hydroxyl groups in a certain amount of the polymer is ¹
It can be determined by 1 H-NMR.

The reaction temperature of the end-capping reaction in the present invention is usually 250 to 36 after adding the end-capping agent to the polymer.
It is suitable to carry out the reaction in the range of 0 ° C., preferably 260 to 340 ° C. At a temperature lower than this range, the polymer does not melt, and at a temperature higher than this range, the polymer decomposes and colors, which is not preferable.

The pressure of the end-capping reaction may be normal pressure,
Reduced pressure conditions are preferred because the reaction proceeds rapidly. It is preferably 100 mmHg or less, more preferably 10 mmHg.
It is less than or equal to mmHg, and more preferably less than or equal to 1 mmHg. The reaction time is usually 1 to 30 minutes, preferably 1 to 2
It is 0 minutes and can be 1 to 15 minutes if desired.

In the present invention, the polymer means a polycarbonate which is a polycondensation product of an aromatic dihydroxy compound and a carbonic acid diester.

Here, the aromatic dihydroxy compound is a compound represented by the following formula (VII).

[0045]

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Where X is

[0047]

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Alternatively, it is a direct bond.

R ⁴ and R ⁵ are the same or different and each is a hydrogen atom, a halogen atom or a hydrocarbon group having 1 to 12 carbon atoms. As the hydrocarbon group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms is preferable. Examples of the halogen atom include chlorine, bromine and iodine.

R ⁶ and R ⁷ are the same or different from each other,
It is a halogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms. Examples of the hydrocarbon group include an aliphatic hydrocarbon group having 1 to 12 carbon atoms and an aromatic hydrocarbon group having 6 to 12 carbon atoms. As a halogen atom, chlorine,
Examples include bromine and iodine.

R ⁸ is an alkylene group having 3 to ⁸ carbon atoms. Examples of the alkylene group include a pentyl group and a hexylene group.

M and n are the same or different and each represents 0 or an integer of 1 to 4.

Specific examples of the aromatic dihydroxy compound include 1,1-bis (4-hydroxy-t-butylphenyl) propane, 2,2-bis (4-hydroxyphenyl) propane and 2,2-bis ( Bis (hydroxyaryl) such as 4-hydroxybromophenyl) propane
Alkanes, 1,1-bis (4-hydroxyphenyl)
Bis (hydroxyaryl) such as cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane
Cycloalkanes, 4,4′-dihydroxydiphenyl ether, dihydroxyaryl ethers such as 4,4′-dihydroxy-3,3′-dimethylphenyl ether, 4,4′-dihydroxydiphenyl sulfide,
Dihydroxyaryl sulfides such as 4,4′-dihydroxy-3,3′-dimethylphenyl sulfide,
4,4'-dihydroxydiphenyl sulfoxide, 4,
Dihydroxyaryl sulfoxides such as 4′-dihydroxy-3,3′-dimethylphenyl sulfoxide,
4,4'-dihydroxydiphenyl sulfone, 4,4 '
-Dihydroxy-3,3'-dimethylphenyl sulfone and other dihydroxy aryl sulfones.

Of these, particularly 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A)
Is preferably used. These aromatic dihydroxyl compounds can be used alone or in combination of two or more.

Examples of the carbonic acid diester compounds include diaryl carbonates such as diphenyl carbonate and ditolyl carbonate, dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, and alkyl aryl carbonates such as phenylmethyl carbonate and ethylphenyl carbonate. it can.

Of these, diphenyl carbonate is particularly preferably used. These aromatic dihydroxyl compounds can be used alone or in combination of two or more. These carbonic acid diester compounds are in excess, preferably 1.
It is desirable to use 01 to 1.20 mol.

In the present invention, a catalyst for promoting the transesterification reaction may be used. Specific examples of such a catalyst include hydroxides, alcoholates and phenolates of alkali metals or alkaline earth metals, alkali (earth) metal salts of organic or inorganic acids, and elements of Group 14 elements on the periodic table of elements. Examples thereof include alkali (earth) metal salts of oxo acids or ate complexes, and nitrogen-containing basic compounds.

These compounds can be used in an amount of 10 ^-8 mol to 10 ^-1 mol, preferably 10 ^-7 mol to 10 ^-2 mol, per 1 mol of the aromatic dihydroxyl compound.

These catalysts can be used alone or in combination of two or more kinds. When these catalysts are used in combination, the timing and method of addition may be individually determined according to the purpose, such as adding one catalyst compound at the start of polymerization and adding another catalyst compound during the polymerization. I don't care.

In addition to these catalysts, as a co-catalyst, aluminum, germanium, tin, etc.
The alkoxides and oxides of the 3 to 14 group elements can be used in combination.

These cocatalysts are used in an amount of 0.001 mol to 100 times mol, preferably 0.
It can be used in an amount of 01 to 50 times.

Further, in the present invention, it is preferable to add various stabilizers in a molten state at least once before the start of polymerization, during the polymerization, and after the completion of the polymerization. Examples of the stabilizer include a sulfur-containing acidic compound and / or a derivative formed from the acidic compound, a phenolic stabilizer,
Examples thereof include thioether stabilizers, phosphorus stabilizers, hindered amine stabilizers, epoxy stabilizers, salicylic acid ultraviolet absorbers, and benzotriazole ultraviolet absorbers. These stabilizers can be used alone or in combination of two or more.

The melt polycondensation reaction between the aromatic dihydroxy compound and the carbonic acid diester can be carried out under the same conditions as the conventionally known ordinary method.

Specifically, the first-step reaction was carried out at 80 to 25
Aromatic at a temperature of 0 ° C., preferably 100 to 230 ° C., more preferably 120 to 190 ° C., for 0.5 to 5 hours, preferably 1 to 4 hours, more preferably 1.5 to 3 hours. The dihydroxy compound and diallyl carbonate are reacted. Then, the reaction temperature is raised while raising the vacuum system of the reaction system to carry out the reaction between the aromatic dihydroxy compound and diallyl carbonate, and finally, under reduced pressure of 5 mmHg or less, preferably 1 mmHg or less, 240 to 3
At 20 ° C., a polycondensation reaction between the aromatic dihydroxy compound and diallyl carbonate is performed.

The polycondensation reaction as described above may be carried out continuously or batchwise. Further, the polymerization apparatus used for carrying out the above reaction may be of a tank type, a tube type or a tower type.

The reaction product polycarbonate obtained as described above usually has an intrinsic viscosity [η] of 0.
1 to 1.0, more preferably 0.2 to 0.8.

In the present invention, the polycarbonate obtained as described above is used in the usual range of heat resistance, ultraviolet absorber, release agent, colorant, antistatic agent, lubricant, anti-reflective agent, as long as the object of the present invention is not impaired. A clouding agent, a natural oil, a synthetic oil, a wax, an organic filler, an inorganic filler or the like may be added.

[0068]

According to the present invention, by the melt polymerization method (transesterification method), it is possible to produce a polycarbonate which is not colored and in which a part or all of the polymer terminal hydroxyl groups are blocked. Further, it is possible to suppress burns, coloring, insolubilization, generation of foreign matters, and decrease in molecular weight at a low level during molding or in a device.

[0069]

The present invention will be described in more detail based on the following examples and comparative examples, but the present invention is not limited to these examples. In addition, "parts" in the examples represent parts by weight unless otherwise specified.

In the present invention, the physical properties were measured by the following methods. (I) Intrinsic viscosity [η]: Measured with a Ubbelohde viscometer at 20 ° C. in methylene chloride. (Ii) Terminal hydroxyl group concentration: 0.02 g of the sample was adjusted to 0.
Dissolve in 4 ml of chloroform and ¹ H-NMR at 20 ° C.
(EX-270 manufactured by JEOL Ltd.) was used to measure the terminal hydroxyl group, and the terminal hydroxyl group concentration was measured by the following formula. Terminal hydroxyl concentration (%) = (terminal hydroxyl concentration / total number of terminals)
× 100

[Examples 1 to 6] Bisphenol A228
Parts, 220 parts of diphenyl carbonate and bisphenol A sodium salt as a catalyst and tetramethylammonium hydroxide (2 μmol and 100 μmol, respectively relative to bisphenol A) were charged into a reaction vessel equipped with a stirrer, a distiller and a decompressor, and replaced with nitrogen. After doing
It melted at 140 degrees. After stirring for 30 minutes, the internal temperature was raised to 180 ° C., the reaction was carried out at 100 mmHg for 30 minutes, and the produced phenol was distilled off.

Further, the temperature was gradually reduced while raising the temperature to 200 ° C., and the reaction was carried out while distilling phenol off at 50 mmHg for 30 minutes.

Thereafter, the temperature was gradually raised to 220 mm and 30 mmHg, and the pressure was reduced.
° C, 10 mmHg, 260 ° C, 1 mmHg, 270 ° C
In the same procedure as above, the temperature was raised and the pressure was reduced to 1 mmHg or less to continue the reaction.

Finally, polymerization was carried out at the same temperature and the same pressure for 1 hour,
When the intrinsic viscosity of the polycarbonate resin reached about 0.35, a part of the polymer was sampled and the type and amount of the terminal blocking agent shown in Tables 1 and 2 were added. Then 270 ° C 1
The reaction was continued for 5 minutes at mmHg or less to carry out an end-capping reaction. The concentration of terminal hydroxyl groups of the polymer collected before adding the terminal blocking agent and the polycarbonate obtained after the terminal blocking reaction was measured.

The physical properties of these polycarbonate resins are shown in Tables 1 and 2 below.

[0076]

[Table 1]

[0077]

[Table 2]

[Comparative Examples 1 and 2] In carrying out melt polymerization of polycarbonate in the same manner as in Examples 1 to 6, an experiment was conducted in exactly the same manner except that the types and amounts shown in Table 3 were used as the terminal blocking agent. Was repeated.

The results are shown in Table 3.

[0080]

[Table 3]

Comparing Tables 1 and 2 with Table 3, in the case of the present invention (Examples 1 to 6), compared with the case of using the conventionally known end capping agent (Comparative Examples 1 and 2), It is understood that the concentration of the terminal hydroxyl group is greatly reduced and the polymer is stabilized.

Claims (2)

[Claims] 1. A method for producing a polycarbonate by transesterifying an aromatic dihydroxy compound and a carbonic acid diester compound under melting, which is represented by the following general formula (I) or general formula (II) as a terminal blocking agent. Ketene compound Alternatively, a ketene dimer represented by the general formula (III): [In each formula, R ¹ and R ² are the same or different and have 1 carbon atom
~ 40 hydrocarbon groups. R ³ is a hydrocarbon group having 2 to 20 carbon atoms. ] The manufacturing method of the polycarbonate characterized by using these. 2. A method for producing a polycarbonate by melt transesterification of an aromatic dihydroxy compound and a carbonic acid diester compound, wherein the ketene compound precursor according to claim 1 is used as an end-capping agent. Method for producing polycarbonate.