JPH0446927A - Production of polycarbonate - Google Patents

Abstract

PURPOSE:To obtain a high-molecular weight, chloride-ion-free, colorless transparent polycarbonate without using any toxic phosgene by melt-polycondensing a bisphenol with biphenyl carbonate in the presence of an electron-donating amine compound catalyst and KBH4. CONSTITUTION:A bisphenol [e.g. a compound of formula I, II, III or IV (wherein R1 to R4 are each H, 1-8 C alkyl or phenyl; X is halogen; (n) = 0-4; and (m) = 1-4)] is melt-polycondensed with biphenyl carbonate in the presence of an electron-donating amine compound (e.g. 2-methylimidazole or 4- diethylaminopyridine) and potassium borohydride (KBH4). In this way, a high- molecular weight, substantially chloride ion-free, colorless transparent polycarbonate can be obtained without using any toxic phosgene.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention involves melt polycondensation of dihydric phenol and bisphenyl carbonate, etc. in the presence of an electron-donating amine compound catalyst and potassium borohydride (KBH4). The present invention relates to a method for producing the high molecular weight polycarbonate obtained.

PRIOR ART AND PROBLEMS TO BE SOLVED BY THE INVENTION The high molecular weight polycarbonates of the present invention have a wide range of uses, particularly for injection molding or as glass sheets in place of window panes. It is a general-purpose engineering thermoplastic. Although the interfacial polycondensation method is generally effective for producing polycarbonate, it has drawbacks such as the use of toxic phosgene and the fact that chlorine ions remain in the polycarbonate produced. In order to eliminate these drawbacks, it was proposed in 1983 that polycarbonate could be produced by an interfacial polycondensation reaction between liquid trichloromethyl chloroformate, which is a dimer of phosgene, and a special dihydric phenol instead of toxic phosgene. -182336.

However, there is only a description of 9,9-bis(4-hydroxyphenyl)fluorenes, which are special dihydric phenols. Also, obtaining polycarbonate from 2,2-bis(4-hydroxyphenyl)propane using triphosgene instead of the toxic phosgene has been reported by Angew, Chem, (Angevante, Hemi-).
Bile.

922 (1987), a reaction mechanism in which phosgene is generated has also been proposed.

Furthermore, JP-A-60-51719 proposes a method for producing polycarbonate using a catalyst consisting of a combination of a nitrogen-containing basic compound and a boron compound.
If this catalyst is used, a relatively light-colored polycarbonate can be obtained, but this catalyst has a problem of low polymerization activity.

Furthermore, it has been disclosed in Japanese Patent Application Laid-Open No. 2002-11112 that polycarbonate can be produced by melt polycondensing an aromatic organic hydroxyl compound and a carbonic acid diester using a catalyst consisting of a nitrogen-containing basic compound and an alkali metal compound or an alkaline earth metal compound. −
No. 124934. However, as nitrogen-containing basic compounds, tetraalkylammonium hydroxides, ammonium hydroxides having alkyl, aryl, aralyl groups, etc., tertiary amines,
There are only descriptions of basic salts such as secondary amines, -class amines, tetraalkylborohydrides, and tetraalkylammonium tetraarylborates.

(Means for Solving the Problems) The present inventors used bisphenyl carbonate and divalent phenyl as compounds that generate carbonate bonds to form an electron-donating amine compound and potassium borohydride (KBH4).
The inventors have discovered that a high molecular weight polycarbonate that does not use toxic phosgene and is essentially free of chlorine ions can be obtained by melt polycondensation in the presence of.

The present invention provides (1) a method for producing polycarbonate, which is characterized by subjecting dihydric phenol and bisphenyl carbonate to melt polycondensation in the presence of a catalyst selected from electron-donating amine compounds and potassium borohydride (KBH4); . (2) Dihydric phenol has general formula (I), (II),
(III) A method for producing the polycarbonate described in (1) above, which is represented by (IV).

(R1, R2, R3, R4 are hydrogen, a linear or branched alkyl group having 1 to 8 carbon atoms, or a phenyl group; X is a halogen atom; n=0 to 4; m=1 to 4) It is related to. , (3) A method for producing the polycarbonate copolymer described in (1) or (2) above.

Representative examples of electron-donating amine compounds that can be used in the present invention include N,N-dimethyl-4-aminopyridine, 4-
diethylaminopyridine, 4-pyrrolidinopyridine, 4
-Aminopyridine, 2-aminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 4-hydroxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, 2-mercaptoimidazole 2-aminopyridine Aminoquinoline ,
Henzimidazole, imidazole.

2-methylimidazole 4-methylimidazole diazabicyclooctane (DABCO), 1,8-diaza-bicyclo[5,4,0]-7-undecene (DBU
) etc.

Moreover, the following compounds are mentioned as typical examples of dihydric phenols. As a bisphenol classified into general formula (I), 2,2-bis-(4-hydroxyphenyl)
Propane, 2,2-bis-(4-hydroxyphenyl)
Butane, 2,2-bis-(4-hydroxyphenyl)-
4-methylpentane, 2,2-bis-(4-hydroxyphenyl)octane, 4,4'-dihydroxy-2,2
,2-)liphenylethane, 2,2-bis-(3,5-
Examples include dibromo-4-hydroxyphenyl)propane. Bisphenols classified into general formula (II) include 2,2-bis-(4-hydroxy-3-methylphenyl)propane, 2,2-bis-(4-hydroxy-3-isopropylphenyl)propane, 2, 2-
Bis-(4-hydroxy-3-sec, butylphenyl)propane, 2,2-bis-(3,5-dimethyl-4-
hydroxyphenyl)propane, 2,2-bis-(4,
Examples include hydroxy-3-tert-butylphenyl)propane. Bisphenols classified as general formula (III) include 1.1'-bis-(4-hydroxyphenyl)-p-diisopropylbenzene, i,
Examples include i'-bis-(4-hydroxyphenyl)-m-diisopropylbenzene. As a bisphenol classified into general formula (IV), 1,1-bis-(4
-hydroxyphenyl)cyclohexane.

Furthermore, general formulas (I) and (II).

It is also possible to produce a copolymerized polycarbonate in which two or more dihydric phenols selected from (III) and (IV) are combined.

The process of the invention is carried out by melt polycondensation reaction of a dihydric phenol such as bisphenol A with bisphenyl carbonate using a catalyst selected from electron-donating amine compounds and potassium borohydride (KBH4). .

The temperature at which this reaction proceeds ranges from over 100°C to approximately 300°C.
The range is up to C. Preferably from 130°C to 280°C
°C range. If the temperature is less than 130°C, the reaction rate will be slow, and if it exceeds 300°C, side reactions will likely occur.

The electron-donating amine compound used as a catalyst is 10-1 to 1 mole based on the dihydric phenol present in the reaction system.
0-5 mol is required, preferably 10-2 to 10-4 mol. If it is less than 10-5 mol, the catalytic effect will be low and the polymerization rate of polycarbonate will be slow.
If the amount is 0-1 mol or more, the proportion remaining as a catalyst in the polycarbonate produced will be high, leading to deterioration of the physical properties of the polycarbonate.

Furthermore, potassium borohydride is present in the reaction system with 2
10-2 to 10-7 mol is required, preferably 10-3 to 10-6 mol, based on the hydric phenol.
It is a mole. If it is less than 10-7 mol, the catalytic action will be low and the degree of polymerization of the polycarbonate will not reach the desired degree,
If the amount is 10 −2 mol or more, the proportion remaining as a catalyst in the polycarbonate produced becomes high, leading to deterioration of the physical properties of the polycarbonate.

Further, the required amount of bisaryl carbonate is equivalent to the molar amount of dihydric phenol present in the reaction system. Generally, in order to produce a high molecular weight polycarbonate, 1 mole of a carbonate compound and 1 mole of dihydric phenol must react. If bisphenyl carbonate is used, 2 moles of phenol are produced by the reaction. These 2 moles of phenol are distilled out of the reaction system.

The present invention will be described below with reference to Examples, but the present invention includes:
The invention is not limited to these examples.

(Example) Example 1 2.2-bis(4-hydroxyphenyl)propane 22
．． 8 g (0.1 mol) and 0.1 2-methylimidazole
Add 64 g (2X 10' mol), 0.00539 (I X 10' mol) of potassium borohydride, and 21.4 g (0.1 mol) of bisphenyl carbonate and stir at 180°C for 1 hour under nitrogen. After that, the temperature was gradually increased while reducing the pressure, and finally the temperature was 0.1Toff, 270°C,
The polycondensation reaction was carried out for 1 hour, and the produced phenol was distilled off to obtain a colorless and transparent polycarbonate. The viscosity average molecular weight was measured and found to be Mv=26,000. Further, the glass transition temperature was 150°C.

The viscosity average molecular weight was measured by measuring the intrinsic viscosity [r1] of a methylsin chloride solution at 20°C using an Ubbelohde viscometer, and calculating the viscosity average molecular weight Mv using the following formula.

[11] = 1.11X10-'(f'7v)O-82 Example 2 Under exactly the same conditions as Example 1, 0.0122 g of 4-dimethylaminopyridine was used instead of 2-methylimidazole.
(I A condensation reaction was performed to obtain a colorless and transparent polycarbonate. When the viscosity average molecular weight was measured, it was found that Mv=28,000. Further, the glass transition temperature was 150°C.

Example 3 2.2-bis(4-hydroxyphenyl)propane 11
．． 4g (50 mol%), 2.2-bis(4-hydroxy, 3-tert-butylphenyl)propane 17.0g
(50 mol%).

0.0122 g of 4-dimethylaminopyridine (I
10'mol) and potassium borohydride 0.000539
g (I x 10' mol) under nitrogen for 2 hours,
A polycarbonate reaction was carried out in the same manner as in Example 1 to obtain a colorless and transparent polycarbonate. This polycarbonate has a viscosity average molecular weight Mv = 25,000 and a glass transition temperature of 1
It was 28°C.

Comparative Example The same treatment was carried out under exactly the same conditions as in Example 3, using pyridine instead of 4-dimethylaminopyridine, and adding 0.00054 g (I x 10'mol) of potassium borohydride. The obtained polycarbonate had a viscosity average molecular weight Mv of 8,000, and although it had the form of polycarbonate, it had a low molecular weight that was not suitable for practical use.

(Effects of the Invention) By using an electron-donating amine compound and potassium borohydride as a catalyst, it was possible to obtain a high-molecular-weight, colorless and transparent polycarbonate that substantially does not contain chlorine ions without using toxic phosgene.

Claims (2)

[Claims] (1) A method for producing polycarbonate, which comprises melt polycondensing dihydric phenol and biphenyl carbonate in the presence of a catalyst selected from electron-donating amine compounds and potassium borohydride (KBH_4). (2) Divalent phenols are (I), (II), (I
II) and (IV), the method for producing polycarbonate according to claim 1. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼( IV) (R_1, R_2, R_3, R_4 are hydrogen or have 1 carbon number
~8 linear or branched alkyl group, or phenyl group, where X is a halogen atom, n = 0 to 4, m = 1 to 4)
(3) A method for producing a polycarbonate copolymer according to claim 1 or 2.