JPH07109347A - 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 an alkaline (earth) metal compound as a catalyst by using a specific phenolic compound. CONSTITUTION:This polycarbonate is obtained by subjecting (A) an aromatic diol compound such as a compound of formula II [A is single bond and bifunctional 1-15C (substituted)hydrocarbon group, 0, S, etc.; X and Y are halogen or 1-6C hydrocarbon group; (p) and (q) are 0-2] and (B) a carbonic acid diester such as a compound of formul-a III (Ar is monofunctional aliphatic group or monofunctional aromatic group) to transesterification reaction in the presence of an alkaline (earth) metal compound as a catalyst by using a phenolic compound of formula I (R1, R2, R4 and R5 are H or 1-4C alkyl; R3 is alkylene).

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, and more specifically, to an aromatic diol compound in the presence of an alkali metal compound and / or an alkaline earth metal compound catalyst. This is a method in which a phenolic compound having a specific structure is used together when reacting with a carbonic acid diester, and a polycarbonate having excellent hue and thermal stability can be obtained.

[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.

For this reason, it is known to use various phosphorus compounds in order to stabilize the reaction system in the polycondensation reaction together with the catalyst in the transesterification reaction, or to use the phosphorus compound and the hindered phenol together. . For example, (1) a method of using a phosphonite compound and a hindered phenol compound in the presence of a quaternary nitrogen compound catalyst (JP-A-61-151236). (2)
A method in which a dialkyl phenylphosphonate is used in the presence of a KBH ₄ catalyst (JP-A-62-158719, JP-A-62-169821). (3) Method of melt polycondensation using an electron-donating phosphorus compound as a catalyst [JP-A-3-5
4223). (4) Transesterification reaction There is a method of using phosphorous acid and a phosphorous acid ester compound in combination in the presence of a metal compound catalyst (JP-A-5-78469). 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]

Means for Solving the Problems The present inventors have made the present invention as a result of extensive 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 using an alkali metal compound and / or an alkaline earth metal compound as a catalyst. In the method, the reaction is carried out in the presence of a phenol compound having a specific structure.

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

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 (2).

[Chemical 2]

(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- , is selected from the group consisting of divalent groups, X and Y are halogen, or a hydrocarbon group having 1 to 6 carbon atoms and are the same or different from each other. Alternatively, p and q are integers from 0 to 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 (3).

[Chemical 3]

(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 (3) 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, preferably 50 mol% or less, more preferably 30 mol% or less of dicarboxylic acid or dicarboxylic acid ester can 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 such a dicarboxylic acid or dicarboxylic acid ester is used in combination with a carbonic acid diester, 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 the range 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 compound containing three phenolic hydroxyl groups is particularly 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-hydroxyary-)
) Oxyindole (= isatin bisphenol),
Examples thereof include 5-chloroisatin bisphenol, 5-bromoisatin bisphenol, trimellitic acid, 1,3,5-benzenetricarboxylic acid and pyromellitic acid.

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.

Specific examples of the alkali metal compound which is a transesterification reaction catalyst used in the present invention include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogencarbonate, potassium hydrogencarbonate, lithium hydrogencarbonate and carbonic acid. Sodium, 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, benzoic acid Potassium, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, hydrogen phosphate 2
Lithium, disodium phenylphosphate, dipotassium phenylphosphate, dilithium phenylphosphate, disodium salt of bisphenol A, dipotassium salt, dilithium salt, sodium salt of phenol, potassium salt, lithium salt, etc. 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 carbonic acid. Calcium, 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 compounds and catalysts of the alkaline earth-earth compounds are 1 × 10 ^-9 to 1 × 10 ^-3 mol, preferably 1 × 10 ³ mol, per mol of the aromatic diol compound.
^-7 to 1 x 10 ^-5 mol is used.

The feature of the present invention resides in that the phenolic compound having the structure represented by the formula 1 is present under the melt polycondensation reaction condition.

The phenolic compound represented by the above formula is specifically 2,2'-methylenebis (4-methyl-6-).
t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 2,
2'-methylenebis (4-propyl-6-t-butylphenol), 2- (2-hydroxy-3,5-dimethylbenzyl) -4-methyl-6-t-butylpheno-
2- (2-hydroxy-3,5-dimethylbenzyl) -4,6-di-t-butylphenol, 2- (2
-Hydroxy-3-methyl-5-ethylbenzyl) -4
-Methyl-6-propylphenol, 2- (2-hydroxy-3-t-butyl-5-ethylbenzyl) -4-
Methyl-6-t-butylphenol, 2,2'-ethylenebis (4-methyl-6-t-butylphenol),
2,2'-ethylenebis (4-ethyl-6-t-butylphenol), 2,2'-ethylenebis (4-propyl-6-t-butylphenol) and the like can be mentioned.

Among the above compounds, 2,2 'is particularly preferable.
-Methylenebis (4-methyl-6-t-butylpheno-
,), 2,2′-methylenebis (4-ethyl-6-t)
-Butylphenol), 2,2'-methylenebis (4
-Propyl-6-t-butylphenol), 2,2 '
-Ethylenebis (4-methyl-6-t-butylpheno-
, 2,2′-ethylenebis (4-ethyl-6-t)
-Butylphenol) and the like are preferred. These pheno
These ru-based compounds may be used alone or in admixture of two or more.

The phenol used in the method of the present invention
The amount of the ru-based compound 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 1 × 10 ⁻⁷ to 1 × 10 ⁻² mol, based on 1 mol of an aromatic diol compound,
It is preferably used in an amount of 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mol.

In the present invention, the above phenol compound may be added at any reaction step in the transesterification reaction step, but it may be added to the reaction system before the reaction step at the maximum temperature is reached. is necessary. For convenience, it can be used from the initial stage of the reaction, that is, by adding and mixing it together with the starting monomer such as the aromatic diol compound, the carbonic acid diester compound and the transesterification reaction catalyst.

The transesterification reaction in the present invention can be carried out by a known melt polycondensation method of aromatic polycarbonate except that a phenol compound having a specific structure is added during the reaction. That is, using the above raw materials, melt polycondensation is carried out while removing by-products generated by the transesterification reaction under heating / normal pressure or reduced pressure to the outside of the system, but the reaction is generally carried out in two or more steps. It is carried out in multiple steps.

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), calcium hydroxide 7.5 × 10 ^-7
Mol, 2,2'-methylenebis (4-methyl-6-t-
(Butylphenol) 7.5 × 10 ⁻⁵ mol was placed in a reactor equipped with a 1 L stirrer and a distillation device, and was placed under a nitrogen atmosphere.
After holding at 180 ℃ for 0.5 hours, decompression degree is 100mm
At the same time as Hg, the temperature was raised to 280 ° C. at a rate of 25 ° C./hr. The degree of reduced pressure in the reaction vessel was set to 50 mmHg about 1 hour after the start of the temperature rise, and the degree of reduced pressure was set to 1 mmHg or less 1 hour later, and the reaction was carried out under stirring for about 6 hours in total. As a result, the obtained polycarbonate had Mv = 23600, terminal OH = 0.013% by weight,
The degree of coloring was small with APHA15 before melting and APHA20 after melting, 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 kinds and amounts of the alkali metal compound and the phenol compound were used as shown in Table 1. The results are shown in Table-1.

Comparative Examples 1 to 3 The procedure of Example 1 was repeated except that the phenol compound was not used and the amount of the alkali metal compound or the alkaline earth metal compound was used as shown in Table 2. did. The results are shown in Table-2.

[0035]

According to the method of the present invention, a phenol compound having a specific structure is allowed to coexist with a transesterification catalyst such as an alkali metal compound or an alkaline earth metal compound during polycondensation. A polycarbonate having excellent hue and heat stability can be obtained, which is an industrially extremely effective method.

[Table 1] Table-1

In the table, APHA after melting; under nitrogen stream 32
Evaluation of hue after heating at 0 ° C. for 1 hour The phenol compounds A, B, C and D are the following compounds. A; 2,2'-methylenebis (4-ethyl-6-t-
Butylphenol) B; 2,2'-methylenebis (4-propyl-6-t)
-Butylphenol) C; 2,2'-ethylenebis (4-methyl-6-t-)
Butylphenol) D; 2,2'-ethylenebis (4-ethyl-6-t-)
Butylphenol)

[Table 2] Table-2

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Atsushi Hirashima 22 Wadai, Tsukuba, Ibaraki Mitsubishi Gas Chemical Co., Ltd.

Claims (2)

[Claims] 1. A method for producing polycarbonate by transesterification between an aromatic diol compound and a carbonic acid diester, wherein a) an alkali metal compound and / or an alkaline earth metal compound is used as a catalyst, and b). A method for producing a polycarbonate, which comprises using a phenol compound represented by the following formula (1) in combination. [Chemical 1] _{(R 1, R 2, R} 4, R 5 represents an alkyl group or hydrogen having 1 to 4 carbon atoms, it may be the same or different, R ₃
Represents an alkylene group. ) 2. An alkali metal compound or an alkaline earth metal compound is added in an amount of 1 × 1 to 1 mol of the aromatic diol compound.
The method according to claim 1, wherein 0 ^-9 to 1 x 10 ^-3 mol and 1 x 10 ^-7 to 1 x 10 ^-2 mol of the phenol compound represented by the formula (1) are used.