JPH06340736A - Method for producing polycarbonate - Google Patents

Abstract

(57) [Summary] [Objective] To provide a polycarbonate excellent in high temperature stability and melt moldability. The present invention relates to an alkyl sulfonic acid ester represented by the following formula (a) when a polycarbonate is produced by melt polycondensation of an aromatic dihydroxy compound and a carbonic acid diester in the presence of a catalyst. [In the formula, R ₁ represents a linear or branched alkyl group having 1 to 20 carbon atoms, and R ₂ represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms. ] Is present, a method for producing a polycarbonate.

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, and more particularly to a method for producing a polycarbonate which is excellent in high temperature stability and melt moldability.

[0002]

2. Description of the Related Art Polycarbonate is excellent in mechanical properties such as impact resistance and transparency and has various uses. Known methods for producing polycarbonate include an interfacial method in which a dihydroxy compound and phosgene are directly reacted, or a melting method in which a dihydroxy compound and a carbonic acid diester are transesterified under heating and reduced pressure.

Of these, the latter has the advantage of being able to produce polycarbonate at a lower cost than the former interface method, and is environmentally preferable because it does not use a solvent such as methylene chloride.

In the conventional method for producing a polycarbonate by a melting method, an alkali metal compound, an alkaline earth metal compound or the like is usually used as a catalyst in an amount of 10 ^-3 to 10 ^-6 mol based on 1 mol of the aromatic dihydroxy compound. Used in. However, the polycarbonate obtained by using such a catalytic amount lacks melt stability, that is,
When the polycarbonate is melt-molded, a part thereof may be thermally decomposed, and there is a problem that the molecular weight is lowered, the coloring is caused, and the transparency is lowered.

Japanese Patent Laid-Open No. 63-51429 proposes a method for producing a polycarbonate having excellent high-temperature stability by using a sulfonate such as phenyl toluenesulfonate. Since it is an aromatic sulfonic acid phenyl ester, the obtained polycarbonate is excellent in high temperature stability but does not contribute to the improvement of melt moldability. For this reason, the advent of a method for producing a polycarbonate having excellent stability at high temperature and excellent melt moldability is desired.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have studied the method for producing such a polycarbonate, and as a result, by adding an organic compound represented by the above formula (a), both high temperature stability and melt moldability are improved. The present invention has been completed by finding that an excellent polycarbonate can be produced.

Therefore, one object of the present invention is to provide a method for producing a polycarbonate which is excellent in stability at high temperature and is excellent in melt moldability. Other objects of the present invention will be apparent from the following description.

[0008]

[Means for Solving the Problems] That is, the present invention relates to an alkylsulfonic acid represented by the following formula (a) when a polycarbonate is produced by melt polycondensation of an aromatic dihydroxy compound and a carbonic acid diester in the presence of a catalyst. ester

[0009]

[Chemical 2]

[In the formula, R ₁ represents a linear or branched alkyl group having 1 to 20 carbon atoms, and R ₂ represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms. ] Is present, a method for producing a polycarbonate.

The aromatic dihydroxy compound used in the present invention is a compound represented by the following formula (b).

[0012]

[Chemical 3]

Where X is

[0014]

[Chemical 4]

R ₅ and R ₆ are the same or different and are a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or 6 to 10 carbon atoms.
Represents an optionally substituted aryl group. Examples of the alkyl group include a methyl group, an ethyl group and a propyl group. A phenyl group is mentioned as an aryl group.

R ₇ is an alkylene group having 3 to 8 carbon atoms. Examples of the alkylene group include a pentylene group and a hexylene group.

R ₃ and R ₄ are the same or different and each represents a halogen atom or an alkyl group having 1 to 5 carbon atoms. Examples of the halogen atom include chlorine and bromine. Examples of the alkyl group include a methyl group and a t-butyl group.

M and n are the same or different and are 0, 1 or 2.

Specifically, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl)
Ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane ,
2,2-bis (4-hydroxy-3-methylphenyl)
Propane, 1,1-bis (4-hydroxy-t-butylphenyl) propane, 2,2-bis (4-hydroxy-)
Bis (hydroxyaryl) alkanes such as 3-bromophenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cyclo such as 1,1-bis (4-hydroxyphenyl) cyclohexane Alkanes, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3
Dihydroxy aryl ethers such as 3'-dimethylphenyl ether, 4,4'-dihydroxydiphenyl sulfide, dihydroxy diaryl sulfides such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, 4,4'-dihydroxy Dihydroxy diaryl sulfoxides such as diphenyl sulfoxide, 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfoxide, 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone, etc. The dihydroxy diaryl sulfones and the like are used. Of these, 2,2-bis (4-hydroxyphenyl) propane is particularly preferable.

The carbonic acid diester used in the present invention includes optionally substituted aryl having 6 to 10 carbon atoms,
Araalkyl, C1-C5 alkyl, C3-C8
Examples thereof include cycloalkyl and other esters.

Specific examples include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate and dicyclohexyl carbonate. Used. Of these, diphenyl carbonate is particularly preferable.

These carbonic acid diesters may contain dicarboxylic acid or dicarboxylic acid ester. The dicarboxylic acid or dicarboxylic acid ester is not particularly limited in carbon number, and specifically,
Examples thereof include terephthalic acid, isophthalic acid, diphenyl terephthalate, and diphenyl isophthalate.

When the above-mentioned dicarboxylic acid or dicarboxylic acid ester is used in combination with carbonic acid diester,
Although a polyester polycarbonate can be obtained, the method for producing the polycarbonate of the present invention also includes the method for producing the polyester polycarbonate.

The amount of the carbonic acid diester used is 80 to 300 mol%, preferably 90 to 280 mol%, particularly preferably 1 based on the aromatic dihydroxy compound (b).
It is preferably used in the range of 0 to 250 mol%.

The alkyl sulfonate used in the present invention is represented by the following formula (a):

[0026]

[Chemical 5]

In the formula, R ₁ is a linear or branched alkyl group having 1 to 20 carbon atoms. Preferably, the carbon number is 1 to
10 linear or branched alkyl groups. R
₂ is a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms. 1 carbon atom as an alkyl group
Those of 10 are preferable.

Specifically, phenyl methyl sulfonate,
Phenyl ethyl sulfonate, phenyl n-propyl sulfonate, phenyl i-propyl sulfonate, phenyl n-butyl sulfonate, phenyl i-butyl sulfonate,
Phenyl t-butyl sulfonate, phenyl n-pentyl sulfonate, phenyl i-pentyl sulfonate, phenyl neopentyl sulfonate and the like are used.

The amount of the alkyl sulfonic acid ester represented by the formula (a) used is 10 ^-6 to 10 ^-1 mol%, preferably 1 based on the aromatic dihydroxy compound.
It can be used in the range of 0 ^-5 to 10 ^-2 mol%. Outside of the above range, there are problems that the physical properties of the obtained polycarbonate are adversely affected and that a high-molecular weight polycarbonate cannot be obtained. The timing of addition of the alkyl sulfonate is not limited to batch charging at the start of the reaction, and addition to the reaction or sequential addition may be preferably performed.

The catalyst used in the present invention is not particularly limited as long as it can accelerate the polymerization reaction. For example, (i) the alkali metal compound may be sodium hydroxide, potassium hydroxide, Lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, 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, potassium benzoate, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium salt of bisphenol A, dipotassium salt, dilithiate Arm salts, the sodium salt of phenol, potassium salt, and lithium salt.

(Ii) As the alkaline earth metal compound,
Specifically, calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, acetic acid. Examples thereof include calcium, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate.

(Iii) Specific examples of the quaternary ammonium hydride compound include tetramethylammonium hydroxide (Me ₄ NOH), tetraethylammonium hydroxide (Et ₄ NOH), and tetrabutylammonium hydroxide (Bu ₄ NOH). ), Trimethylbenzyl ammonium hydroxide, and the like.

These catalysts may be used either individually or in combination of two or more.

The amount of the above catalyst used is in the range of 10 ^-6 to 10 mol%, preferably 10 ^-5 to 1 mol%, particularly preferably 10 ^-4 to 10 ^-1 mol% based on the aromatic dihydroxy compound. Can be used in. If you deviate from the above usage range,
There are problems that the physical properties of the obtained polycarbonate are adversely affected, and the polycondensation reaction does not proceed sufficiently to obtain a high-molecular weight polycarbonate.

The polycondensation reaction between the aromatic dihydroxy compound and the carbonic acid diester can be carried out under the same conditions as the conventionally known polycondensation reaction conditions between the aromatic dihydroxy compound and the carbonic acid diester. In the first stage reaction is 80 to 250 ° C., preferably 100 to 240
0-5 at a temperature of 120-230 ° C, more preferably 120-230 ° C.
Time, preferably 0 to 4 hours, more preferably 0.2
Both are reacted at atmospheric pressure for 5 to 3 hours. Then, the reaction temperature is raised while reducing the pressure of the reaction system to carry out the reaction between the aromatic dihydroxy compound and the carbonic acid diester, and finally 1 m.
A polycondensation reaction between an aromatic dihydroxy compound and a carbonic acid diester is carried out at a temperature of 200 to 320 ° C. under a reduced pressure of mHg or less.

The reaction between the aromatic dihydroxy compound and the carbonic acid diester as described above 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.

[0037]

INDUSTRIAL APPLICABILITY According to the present invention, when an aromatic dihydroxy compound and a carbonic acid diester are melt-polycondensed in the presence of a catalyst to produce a polycarbonate, the use of the above alkyl sulfonic acid ester provides excellent stability at high temperature.
Moreover, it is possible to produce a polycarbonate having excellent melt moldability.

The present invention is described below with reference to examples, but the present invention is not limited to these examples.

[0039]

Examples 1 and 2, Comparative Examples 1 and 2 2,2-bis (4
-Hydroxyphenyl) propane 137 g (0.6 mol), diphenyl carbonate 135 g (0.63 mol), a predetermined amount of catalyst and a predetermined amount of sulfonate were added and dissolved by stirring at 180 ° C. for 30 minutes under N ₂ atmosphere. .

Next, the reaction was carried out at the same temperature under a reduced pressure of 100 mmHg for 30 minutes, and further under a reduced pressure of 30 mmHg for 30 minutes. This is heated to 290 ° C., 0.5 mmHg
The reaction was performed for 60 minutes under reduced pressure. The polymer obtained and the IV and MFR after heat aging are shown in Table 1.

IV, MFR and heat aging in Table 1 were tested in the following manner. IV: Measured at 20 ° C. in methylene chloride. Heat aging: Heat aged at 320 ° C. for 15 minutes. MFR: Based on the method of JIS K-7210.

As a comparison, a test was conducted without using a sulfonate ester (Comparative Example 1), but it was found that the MFR increased after heat aging and the high temperature stability was poor.
Moreover, although the thing using an aryl sulfonic acid ester was performed (Comparative Example 2), it was found that the MFR value in the initial physical properties was small and the melt moldability was poor.

[0043]

[Table 1]

Claims (1)

[Claims] 1. When producing a polycarbonate by melt polycondensation of an aromatic dihydroxy compound and a carbonic acid diester in the presence of a catalyst, an alkyl sulfonic acid ester represented by the following formula (a): [In the formula, R ₁ represents a linear or branched alkyl group having 1 to 20 carbon atoms, and R ₂ represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms. ] The manufacturing method of the polycarbonate characterized by making it exist.