JPH07109344A - Production of polycarbonate - Google Patents

Abstract

PURPOSE:To obtain a polycarbonate having excellent hue and heat stability by reacting an aromatic diol with a carbonic acid diester in the presence of a specific compound as a transesterification catalyst. CONSTITUTION:This polycarbonate is obtained by reacting (A) an aromatic diol, compound such as a compound of formula II [A is single bond and bifunctional 1-15C (substituted)hydrocarbon group, O, S, etc.; X and Y are halogen or 1-6C hydrocarbon group; (p) and (q) are 0-2] with (B) a carbonic acid diester such as a compound of formula III (Ar is monofunctional aliphatic group or monofunctional aromatic group) in the presence of a benzotriazole (metal salt) containing a group of formula I as a transesterification catalyst.

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 so-called transesterification reaction. More specifically, in the method for producing a polycarbonate by a transesterification reaction between an aromatic diol compound and a carbonic acid diester, the ester This is a method of using benzotriazole or its metal salt as an exchange catalyst, and it is possible to obtain a polycarbonate having excellent hue and thermal stability.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a polycarbonate, a method in which an aromatic diol compound and phosgene are directly reacted (interfacial method) or an aromatic diol compound and a carbonic acid diester are transesterified There is a method [transesterification method]. However, since the interfacial method uses harmful phosgene and methylene chloride which is a halogen-based solvent, the transesterification method has recently been reviewed in consideration of environmental protection.

In the method for producing a polycarbonate by the transesterification method, an alkali metal compound, an alkaline earth metal compound or the like is usually used as a catalyst.
However, in the method using these catalysts, the reaction product is colored during the polycondensation, and there is a problem in the hue and thermal stability of the resulting polycarbonate.

Therefore, a compound having a special structure is used alone as a catalyst in the transesterification reaction,
Alternatively, it is known to be used in combination with alkali metal compounds and the like. For example, (1) a method in which an iminocarboxylic acid or a metal salt thereof is used alone as a catalyst, or is used in combination with an alkali metal compound, an alkaline earth metal compound or the like (JP-A-55-142025), (2) tetraalkyl A method in which a nitrogen-containing basic compound represented by ammonium hydroxide and an alkali metal compound or an alkaline earth metal compound are used in combination (JP-A-2-124934).
No.), (3) a method of melt polycondensation using an electron-donating amine compound represented by a nucleus-substituted pyridine as a catalyst (JP-A-2-212518) and the like. However, even with these methods, it is still difficult to obtain a polycarbonate having excellent hue and thermal stability.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems in the quality of aromatic polycarbonate obtained by the transesterification method, and to improve the hue and thermal stability. An object is to provide an improved method for producing aromatic polycarbonate.

[0006]

The present inventors have made the present invention as a result of earnest studies to solve these problems. That is, the present invention is a method for producing an aromatic polycarbonate by transesterifying an aromatic diol compound and a carbonic acid diester compound, and in the method for producing an aromatic polycarbonate, a benzotriazole or a metal salt thereof is used as a transesterification catalyst. Used in addition to benzotriazo-
And a metal salt thereof and an alkali metal compound and / or an alkaline earth metal compound are used in combination.

According to the method of the present invention, the reactivity is improved and the molecular weight of the obtained polymer is sufficiently high.
A polycarbonate having excellent hue and heat stability immediately after polycondensation and after heating and melting can be obtained economically.

The method for producing a polycarbonate according to the present invention will be specifically described below. Examples of the aromatic diol compounds used in the present invention include compounds represented by the following formula (1).

[Chemical 1]

(In the formula, A is a single bond, a substituted or unsubstituted linear, branched or cyclic divalent hydrocarbon group having 1 to 15 carbon atoms, and -O-, -S-, -CO. -, -SO
-, - SO ₂ - those selected from the group consisting of divalent groups represented by, X and Y are halogen, or carbon atoms 1
6 may be the same or different from each other, and p and q are integers of 0-2. )

Specific examples of the aromatic diol compound include bis (4-hydroxyphenyl) methane,
1,1-bis (4-hydroxyphenyl) ethane,
2,2-bis (4-hydroxyphenyl) propane,
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-dibromophenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxy) Phenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl)
Cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxy-3,
3'-dimethyldiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfone,
4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone and the like can be mentioned. Of these, 2,2-bis (4-hydroxyphenyl) propane is particularly preferably used. Further, these aromatic diol compounds can be used alone or in combination.

The carbonic acid diester used in the present invention is a compound represented by the following general formula (2).

[Chemical 2]

(In the formula, Ar is a monovalent aliphatic or monovalent aromatic group, and Ar may be the same or different.)

The carbonic acid diester represented by the above general formula (2) is, for example, diphenyl carbonate or substituted diphenyl carbonate, ditolyl carbonate, dimethyl carbonate, diethyl carbonate. Examples thereof include dibutyl carbonate, dibutyl carbonate, dicyclohexyl carbonate and the like, but diphenyl carbonate and substituted diphenyl carbonate are particularly preferable. You may use these carbonic acid diesters individually or in mixture of 2 or more types.

In addition to the above-mentioned carbonic acid diester, 50 mol% or less, more preferably 30 mol% or less of dicarboxylic acid or dicarboxylic acid ester may be used. As such a dicarboxylic acid or dicarboxylic acid ester, terephthalic acid, isophthalic acid, diphenyl terephthalate, diphenyl isophthalate or the like is used. When these dicarboxylic acids or dicarboxylic acid esters are used in combination with carbonic acid diesters,
A polyester carbonate is obtained.

These carbonic acid diester compounds are generally used in excess with respect to 1 mol of the aromatic diol compound, and 1.01 to 1.30 mol, preferably 1.0.
It is desirable to use it in an amount of 2 to 1.20 mol.

Further, in the present invention, when producing a polycarbonate, a polyfunctional compound having three or more functional groups in one molecule is used together with the aromatic diol compound and the carbonic acid diester as described above. You can also As such a polyfunctional compound, a compound having a phenolic hydroxyl group or a carboxyl group is preferable, and a phenol-containing compound is particularly preferable.
A compound containing three hydroxyl groups is preferable. Specifically, phloroglucin, 2,6-dimethyl-2,4,6-
Tri (4-hydroxyphenyl) heptene-3,4,
6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-2,1,3,5-tri (2-hydroxyphenyl) benzoyl, 1,1,1-tris (4
-Hydroxyphenyl) ethane, 2,6-bis (2-
Hydroxy-5-methylbenzyl) -4-methylphenol, 3,3-bis (4-hydroxyaryl) oxyindole (= isatin bisphenol), 5-chloroisatin bisphenol , 5-bromoisatin bisphenol, trimellitic acid, 1,3,5-benzenetricarboxylic acid, pyromellitic acid and the like.

The polyfunctional compound is used in an amount of usually 0.01 to 3 mol%, preferably 0.05 to 1 mol% based on 1 mol of the aromatic diol compound.

The benzotriazole or its metal salt compound used as a catalyst for the transesterification reaction in the present invention is a compound having a group represented by the following general formula (3) in the molecule.

[Chemical 3]

Specifically, benzotriazole, methylbenzotriazole, ethylbenzotriazole, butylbenzotriazole, 1- (hydroxymethyl) benzotriazole, 1- (2,3- Dihydroxypropyl) benzotriazole, 1- (carboxymethyl) benzotriazole, 1- (1,2-dicarboxyethyl) benzotriazole, benzotriazol-5-carboxylic acid, 1- (hydroxymethyl) methylbenzotri Azoles, 1- (2,3-dihydroxypropyl) methylbenzotriazol, 1- (carboxymethyl) methylbenzotriazol, 1- (1,2-dicarboxyethyl) methylbenzotriazol And the like.

Examples of the metal salts of benzotriazoles include alkali metals such as sodium and potassium, alkaline earth metals such as magnesium, calcium and barium, zinc, cadmium, copper, tin, lead, manganese and cobalt. , And metal salts such as nickel.

The amount of the benzotriazole or its metal salt used is sufficient as long as it substantially prevents the deterioration of the hue of the polymer during the transesterification reaction. The amount used is generally in the range of 1 × 10 ⁻⁹ to 1 × 10 ⁻³ mol, preferably 1 × 10 ⁻⁷ to 1 × 10 ⁻⁵ mol, based on 1 mol of the aromatic diol compound. To be

Specific examples of the alkali metal compound which is the transesterification reaction catalyst used in the present invention include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogencarbonate, potassium hydrogencarbonate and lithium hydrogencarbonate. , Sodium carbonate, potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, sodium stearate, potassium stearate, lithium stearate, sodium borohydride, lithium borohydride, sodium phenyl borohydride, sodium benzoate, 2 of potassium benzoate, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium phenylphosphate, dipotassium phenylphosphate, dilithium phenylphosphate, bisphenol A 2 Nato Umushio, dipotassium salt, dilithium salt, phenol - sodium salt of Le, potassium salt, lithium salt or the like is used.

Specific 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 and calcium carbonate. , Barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate and the like are used.

These alkali metal compound and alkaline earth metal compound catalysts are used in an amount of 1 × 10 ^-9 to 1 × 10 ^-3 mol, preferably 1 × 10 ^-7 to 1 mol of the aromatic diol compound.
It is used in the range of 1 × 10 ⁻⁵ mol.

In the present invention, the above-mentioned benzotriazo-
It is not particularly limited as long as it is during the transesterification reaction step of addition period 1 of the silane or its metal salt, but it is necessary to add it to the reaction system by the time the reaction step of the highest temperature is reached. When used alone, it is simply added from the initial stage of the reaction, that is, at the same time as the starting monomer, an aromatic diol compound and a carbonic acid diester compound are added and mixed, but when used in combination with an alkali metal compound or a certain borrowed earth metal compound. Can be added at the same time as these exchange reaction metal compound catalysts, ie, alkali metal compounds or alkaline earth metal compounds.

The transesterification reaction in the present invention can be carried out by a known melt polycondensation method of aromatic polycarbonate except that a benzotriazole or a metal salt compound thereof is used as a catalyst. That is, melt polycondensation is carried out using the above-mentioned raw materials while removing by-products by transesterification under heating / normal pressure or reduced pressure, but the reaction is generally carried out in two or more multi-step processes. It

Specifically, the first step reaction is carried out in the range of 120 to 2
The reaction is carried out at a temperature of 60 ° C., preferably 180 to 240 ° C. for 0 to 5 hours, preferably 0.5 to 3 hours under a relatively gentle reduced pressure. Then, the reaction temperature is raised while increasing the degree of vacuum of the reaction system to cause the reaction between the aromatic diol compound and the carbonic acid diester, and finally, under a reduced pressure of 1 mmHg or less, 24
The polycondensation reaction is performed at a temperature of 0 to 320 ° C. The reaction between the aromatic diol compound and the carbonic acid diester may be carried out continuously or batchwise. The reactor used for carrying out the above reaction may be of a tank type, a tube type or a column type.

[0028]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. The polycarbonate obtained was evaluated by the following method.

(1) Molecular Weight The intrinsic viscosity [η] at 20 ° C. in methylene chloride was measured using an Ubbelohde viscometer and determined from the following formula. [Η] = 1.11 × 10 ⁻⁴ (Mv) ^0.83

(2) Hue 4 g of the polycarbonate obtained was added to 25 ml of methylene chloride.
It was dissolved in and was visually evaluated with an APHA standard solution. (The smaller the value, the better the hue)

(3) Terminal OH Content Colorimetric determination was carried out by the titanium tetrachloride / acetic acid method (Makromol Chem. 88 215 (1965)).

Example 1 2,2-bis (4-hydroxyphenyl) propane 11
4 g (0.50 mol), diphenyl carbonate 118
g (0.55 mol) and 7.5 × 10 ⁻⁷ mol of a potassium salt of methylbenzotriazole were placed in a 1 L reactor equipped with a stirrer and a distillation device, and the mixture was stirred at 180 ° C. under a nitrogen atmosphere for 0.5 at 0.5 ° C. After holding for a time, the degree of pressure reduction was set to 100 mmHg, and at the same time, the temperature was raised to 280 ° C. at a rate of 25 ° C./hr.
Approximately 1 hour after the start of heating, the degree of pressure reduction in the reaction vessel is set to
mmHg, and after 1 hour, decompression degree is 1m
The reaction was performed with stirring at a pressure of mHg or less for a total of about 6 hours. As a result, the obtained polycarbonate had Mv = 2420.
0, terminal OH = 0.012% by weight, APHA1 before melting
5. After melting, the degree of coloring was small with APHA20, and the hue and thermal stability were good.

Examples 2 to 5 The same procedure as in Example 1 was carried out except that the types and amounts of benzotriazoles or their metal salts and alkali metal compounds were used as shown in Table 1. The results are shown in Table-1.

Comparative Examples 1 to 3 The same as Example 1 except that the benzotriazoles or metal salts thereof were not used, only the alkali metal compound was used and the kind and amount thereof were as shown in Table 2. Carried out by the method. The results are shown in Table-2.

[0035]

According to the method of the present invention, by using benzotriazole or its metal salt as a catalyst during polycondensation, a polycarbonate having excellent hue and thermal stability is obtained.
This is a very effective method industrially.

[Table 1]

In the table, APHA after melting; under nitrogen stream 32
Evaluation of hue after heating for 1 hour at 0 ° C. Benzotriazoles A, B, C, and D are as follows. A: methylbenzotriazole B; 1- (hydroxymethyl) benzotriazole C; sodium salt of 1- (carboxymethyl) benzotriazole D; 1- (2,3-dihydroxypropyl) benzotriazole

[Table 2]

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[Procedure amendment]

[Submission date] April 1, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025] In the present invention, the addition timing of the benzotriazoles, or a metal salt is not particularly limited as long as the ester interchange reaction step, in the reaction step
It is necessary to add it to the reaction system before the maximum temperature is reached . When used alone, it is simply added from the initial stage of the reaction, that is, at the same time as the raw material monomer, aromatic diol compound and carbonic acid diester compound, but when used in combination with an alkali metal compound or alkaline earth metal compound, these esters are used. The exchange reaction metal compound catalyst, that is, the alkali metal compound or the alkaline earth metal compound, can be added at the same time.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masayuki Nakajima 22 Wadai, Tsukuba, Ibaraki Prefecture Mitsubishi Gas Chemical Co., Ltd.

Claims (4)

[Claims] 1. A method for producing a polycarbonate by a transesterification reaction between an aromatic diol compound and a carbonic acid diester, wherein a benzotriazole or a metal salt thereof is used as a transesterification catalyst. Production method 2. Benzotriazole or its metal salt is added in an amount of 1 × 10 ⁻⁹ to 1 to 1 mol of the aromatic diol compound.
Method according to claim 1, characterized in that ^{x10 -3} mol is used. 3. A method for producing a polycarbonate by a transesterification reaction between an aromatic diol compound and a carbonic acid diester, wherein a benzotriazole, or a metal salt thereof and an alkali metal compound and / or an alkali are used as a catalyst. A method for producing a polycarbonate, which comprises using an earth metal compound. 4. A benzotriazole or a metal salt thereof is added in an amount of 1 × 10 ⁻⁹ to 1 with respect to 1 mol of an aromatic diol compound.
4. The method according to claim 3, wherein 1 × 10 ⁻⁹ to 1 × 10 ⁻³ mol of × 10 ⁻³ mol, alkali metal compound and / or alkaline earth metal compound is used.