JP2901647B2 - Production method of polycarbonate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a high-molecular-weight polycarbonate obtained by melt-polycondensing a dihydric phenol with bisphenyl carbonate in the presence of an electron-donating amine compound catalyst. It is.

(Prior Art and Problems to be Solved by the Invention) The high molecular weight polycarbonate of the present invention has a wide range of applications,
In particular, it is a general-purpose engineering thermoplastic having an application as a glass sheet for injection molding or as a substitute for window glass. The interfacial polycondensation method is generally effective for producing polycarbonate, but has drawbacks such as the use of toxic phosgene and the persistence of chloride ions forming polycarbonate. In order to eliminate these drawbacks, it has been proposed to produce polycarbonate by an interfacial polycondensation reaction with a special dihydric phenol using liquid trichloromethyl chloroformate which is a dimer of phosgene instead of toxic phosgene. -182336.
However, there is only description of 9,9-bis (4-hydroxyphenyl) fluorene which is a special dihydric phenol. It is also known that polycarbonate can be obtained from 2,2-bis (4-hydroxyphenyl) propane using triphosgene instead of toxic phosgene.
W.Chem. (Angewandte, Chemie) 99.922 are described in (1987), a reaction mechanism in which phosgene is generated is also proposed.

(Means for Solving the Problems) The present inventors melt-polycondensate bisphenyl carbonate and a dihydric phenol as compounds for forming a carbonate bond in the presence of an electron-donating amine compound, thereby producing toxic phosgene. It has been found that a high-molecular-weight polycarbonate which is not used and contains essentially no chloride ions can be obtained.

The present invention provides (1) a method for producing a polycarbonate, which comprises melt-polycondensing a dihydric phenol with bisphenylcarbonate in the presence of a catalyst selected from electron-donating amine compounds. (2) The method for producing a polycarbonate according to the above (1), wherein the dihydric phenol is represented by the general formulas (I), (II), (III) and (IV).

(R ₁ , R ₂ , R ₃ and R ₄ are hydrogen or an alkyl group having 1 to 8 carbon atoms containing a straight or branched chain, or a phenyl group, X is a halogen atom and n = 1 to 4, m = 1-4).

Representative examples of the electron donating amine compound that can be used in the present invention include N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 4- (4-methyl-1-piperidinyl) -pyridine, and 4-pyrrolidone. Dinopyridine, 4-aminopyridine, 2-aminopyridine, 2-hydroxypyridine, 2-
Methoxypyridine, 4-methoxypyridine, 4-hydroxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, 2-mercaptoimidazole, 2-aminopyridine, aminoquinoline, imidazole, 2-methylimidazole, 4-methylimidazole, dia Zabicyclooctane (DABCO) and the like.

In addition, typical examples of the dihydric phenol include the following compounds. As bisphenols classified into the 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-triphenylethane, 2,2-bis- (3,5-dibromo-4-hydroxyphenyl) propane and the like. As bisphenols classified into the general formula (II), 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) And propane, 2,2-bis- (4-hydroxy-3-tert-butylphenyl) propane. As bisphenols classified into the general formula (III), 1,1'-bis- (4-hydroxyphenyl) -p-diisopropylbenzene, 1,1'-bis- (4
-Hydroxyphenyl) -m-diisopropylbenzene and the like. As bisphenols classified into the general formula (IV), 1,1-bis (4-hydroxyphenyl)
Cyclohexane is mentioned. Further, general formulas (I),
It is also possible to produce a copolymerized polycarbonate in which two or three or more dihydric phenols selected from (II), (III) and (IV) are combined.

The process of the present invention is carried out by subjecting a dihydric phenol such as bisphenol A to a melt polycondensation reaction with bisphenyl carbonate using a catalyst selected from electron-donating amine compounds.

The temperature at which this reaction proceeds ranges from above 100 ° C to about 300 ° C. Preferably it is in the range of 130 ° C to 280 ° C.
If the temperature is lower than 130 ° C., the reaction rate becomes slow.

The electron-donating amine compound used as a catalyst is 10 ^-1 mol to 10 ^-5 mol based on the dihydric phenol present in the reaction system.
A mole is required, but preferably from 10 ^-2 to 10 ^-4 mole. When the amount is less than 10 ^-5 mol, the catalytic action is small, and the polymerization rate of the polycarbonate is slow. When the amount is 10 ^-1 mol or more, the rate of remaining in the polycarbonate produced as a catalyst becomes high, which leads to deterioration of the physical properties of the polycarbonate.

The required amount of bisphenyl carbonate is equivalent to the dihydric phenol present in the reaction system in an equimolar amount. Generally, in order to produce a high molecular polycarbonate, one mole of a carbonate compound and one mole of a dihydric phenol must react. When using bisphenyl carbonate,
Two moles of phenol are formed by the reaction. These two
Molar phenol is distilled out of the reaction system.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

(Example) Example 1 22.8 g of 2,2-bis (4-hydroxyphenyl) propane
(0.1 mol) and 0.164 g of 2-methylimidazole (2 × 10
^-3 mol), 21.4 g (01 mol) of bisphenyl carbonate
After stirring at 180 ° C for 1 hour under nitrogen, the temperature is gradually increased while gradually reducing the pressure, and finally, the phenol produced by the polycondensation reaction at 0.1 ^Torr and 270 ° C for 1 hour is distilled off to remove colorless and transparent. Polycarbonate was obtained. The measured viscosity average molecular weight was v = 29,000. The glass transition point is 150 ℃
Met.

The viscosity average molecular weight was measured by measuring the intrinsic viscosity [η] of the methylene chloride solution at 20 ° C. using an Ubbelohde viscometer, and calculating the viscosity average molecular weight v using the following equation.

[Η] = 1.11 × 10 ⁻⁴ (v) ^0.82 Example 2 0.0122 g (1) of 4-dimethylaminopyridine instead of 2-methylimidazole under the same conditions as in Example 1.
× 10 ^-4 mol), and the mixture was stirred under nitrogen for 2 hours, and subjected to a polycondensation reaction in the same manner as in Example 1 to obtain a colorless and transparent polycarbonate. When the viscosity average molecular weight is measured, v = 2
It was 8,000. Further, the glass transition temperature was 150 ° C.

Example 3 11.4 g of 2,2-bis (4-hydroxyphenyl) propane
(0.05 mol, 50 mol% in the dihydric phenol component), 2,2-bis (4-hydroxy-3-tert-butylphenyl)
17.0 g of propane (0.05 mol, 50 mol% in the dihydric phenol component), 0.068 g (10 ^-3 mol) of imidazole, and 21.4 g (0.1 mol) of bisphenyl carbonate were stirred under nitrogen for 2 hours. A polycondensation reaction was performed in the same manner to obtain a colorless and transparent polycarbonate. The viscosity average molecular weight v of this polycarbonate was 25,000, and the glass transition temperature was 128 ° C.

Comparative Example The same treatment was carried out using pyridine instead of 2-methylimidazole under exactly the same conditions as in Example 1; however, the viscosity average molecular weight v of the obtained polycarbonate was 4,000, and the form of the polycarbonate was not obtained. However, the molecular weight was not suitable for practical use.

(Effect of the Invention) From dihydric phenol and bisphenyl carbonate,
By using an electron-donating amine compound as a catalyst, a colorless and transparent polycarbonate having substantially no chloride ions and having a high molecular weight could be obtained without using toxic phosgene.

Claims (3)

(57) [Claims] 1. A process for producing a polycarbonate, comprising subjecting a dihydric phenol and bisphenyl carbonate to melt polycondensation in the presence of a catalyst selected from an electron-donating amine compound, and distilling off the resulting phenol. 2. A dihydric phenol having the following formula (I) or (I)
The method for producing a polycarbonate according to claim 1, which is a compound represented by (I), (III) or (IV). (R ₁ , R ₂ , R ₃ , and R ₄ are hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms, or a phenyl group, X is a halogen atom, and n = 1 to 4, m = 1-4) 3. The method according to claim 1, wherein the dihydric phenol is of the formula (I), (II) or (II).
The method for producing a polycarbonate according to claim 2, wherein two or more kinds selected from the group consisting of I) and (IV) are used.