JP3188062B2 - Aromatic polycarbonate and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aromatic polycarbonate and a method for producing the same. More particularly, the present invention relates to a method for reducing the amount of a free aromatic monohydroxy compound, the amount of a free aromatic dihydroxy compound and the amount of a free aromatic carbonate diester. And a method for producing the same.

[0002]

2. Description of the Related Art Polycarbonate resins obtained from the interfacial polycondensation of bisphenol A and phosgene are widely used in various applications due to their excellent mechanical and thermal properties, but use toxic phosgene. However, the use of methylene chloride as a solvent has many problems such as destruction of the global environment. In recent years, transesterification methods that do not use methylene chloride or phosgene have been spotlighted. This transesterification method is a method in which the reaction proceeds while removing aromatic monohydroxy compounds such as phenol generated by the reaction out of the system. Therefore, it is inevitable that a free aromatic monohydroxy compound remains in the obtained polycarbonate resin, and a polycarbonate molded product represented by an optical disk or the like using this resin has problems such as corrosiveness and toxicity. In addition, since the polycarbonate in the molten state is pelletized as it is as the polymerization liquid, unreacted aromatic dihydroxy compounds and unreacted free aromatic dihydroxy compounds and aromatic carbonates are not extracted out of the system as in the case of the interfacial polycondensation method. Residual diester is inevitable. Such a polycarbonate molded product represented by an optical disk or the like using a resin causes problems such as burning during molding, a decrease in molecular weight, and a decrease in physical properties.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present inventors
Aromatic polycarbonate obtained by the transesterification method has no problems such as corrosiveness, toxicity, burning during molding, molecular weight reduction and physical property reduction, and it is extremely high quality that can be used as a material for information media such as optical disks. As a result of research, it was found that the residual amounts of the free aromatic monohydroxy compound, the aromatic dihydroxy compound, and the aromatic carbonic diester in the aromatic polycarbonate should each be less than a specific amount. Was.

Further, it is extremely difficult to obtain such an aromatic polycarbonate having high quality even after stirring for a long time under a high vacuum under melting conditions after the transesterification reaction. It was also found that decomposition and coloring occurred and deterioration of quality was observed. The inventors of the present invention have conducted a transesterification reaction of the above-mentioned high-quality aromatic polycarbonate, and once solidified and pulverized into a powder having a specific particle size, while holding the powder under high vacuum under heating conditions. Alternatively, it has been found that the composition can be easily obtained by maintaining the composition under an inert gas flow. In addition, it has been found that even when heated in such a powder state, the aromatic polycarbonate is not decomposed or colored, and a desired high-quality aromatic polycarbonate can be obtained.

[0005]

Thus, according to the present invention, an aromatic polycarbonate obtained by reacting an aromatic dihydroxy compound and an aromatic diester under heating and melting is converted into a powder having an average particle size of 2000 μ or less. And under a temperature condition capable of maintaining a powdery state at 80 ° C. or more, and 1 mmHg
(1) a content of a free aromatic monohydroxy compound is 30 ppm or less, (2) a content of a free aromatic dihydroxy compound is 50 ppm or less, And (3) a method for producing an aromatic polycarbonate having a content of free aromatic carbonate diester of 50 ppm or less is provided. Further, according to the present invention, the aromatic dihydroxy compound and the aromatic carbonate diester are reacted under heating and melting. An aromatic polycarbonate obtained, wherein the aromatic polycarbonate has (1) a content of a free aromatic monohydroxy compound of 30 ppm or less, (2) a content of a free aromatic dihydroxy compound of 50 ppm or less, and (3) An aromatic polycarbonate having a content of free aromatic carbonic diester of 50 ppm or less. Boneto is provided.

Hereinafter, the present invention will be described in more detail. The aromatic polycarbonate that is the object of the present invention is obtained by a transesterification reaction between an aromatic dihydroxy compound and an aromatic diester carbonate. At that time, the aromatic dihydroxy compound used as one raw material is represented by the following general formula.

[0007]

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(Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, W is a bond, 6 alkylidene groups, alkylene groups having 1 to 6 carbon atoms, 3 carbon atoms
-8-cycloalkylidene group, C3-C8 cycloalkylene group, phenyl-substituted C1-C6 alkylene group, oxygen atom, sulfone bond, sulfide bond or sulfoxide bond)

Specific examples of the aromatic dihydroxy compound represented by the above general formula include, for example, bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, and 2,2-bis (4 -Hydroxy-3
-Methylphenyl) propane, 4,4-bis (4-hydroxyphenyl) heptane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5 -Dibromophenyl) propane, bis (4-hydroxyphenyl oxide), bis (3,5-dichloro-4-hydroxyphenyl) oxide, p, p'-dihydroxydiphenyl, 3,3'-dichloro-4,4'- Dihydroxydiphenyl, bis (4-
Hydroxyphenyl) sulfone, bis (3,5-dimethyl-4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfide and bis (4-hydroxyphenyl) sulfoxide.

Further, other than the compounds represented by the above general formula, for example, dihydroxybenzene, resorcinol, hydroquinone, 1,4-dihydroxy-2,5-dichlorobenzene and 1,4-dihydroxy-3-methylbenzene are also aromatic dihydroxybenzenes. It can be used as a compound. Among the above-mentioned aromatic dihydroxy compounds, 2,2-bis (4-hydroxyphenyl) propane is particularly preferred. On the other hand, as another raw material, an aromatic carbonic diester, for example, diphenyl carbonate,
Dinaphthyl carbonate and bis (diphenyl) carbonate are mentioned. Of these, diphenyl carbonate is particularly preferred.

In the transesterification reaction for obtaining an aromatic polycarbonate, the aromatic dihydroxy compound and the aromatic carbonic diester are usually stirred while heating under an inert gas atmosphere to distill off the aromatic monohydroxy compound formed. Done in a way. A polymerization catalyst can be used to increase the polymerization rate. Examples of the polymerization catalyst include hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide and potassium hydroxide; alkali metal salts, alkaline earth metal salts and quaternary ammonium salts of hydroxides of boron and aluminum. Alkoxides of alkali metals and alkaline earth metals; organic acid salts of alkali metals and alkaline earth metals; zinc compounds; boron compounds; silicon compounds; germanium compounds; organotin compounds; Catalysts usually used for esterification and transesterification such as compounds, antimony compounds, manganese compounds, titanium compounds, and zirconium compounds can be used, but are not limited thereto. When using a catalyst, only one type may be used or two or more types may be used in combination.
These catalysts are used in an amount of 0.0001 to 1% by weight, preferably 0.000% by weight, based on the aromatic dihydroxy compound used as the starting material.
It is selected in the range of 5 to 0.5% by weight, more preferably 0.001 to 0.1% by weight.

The present invention is characterized in that the amount of free aromatic monohydroxy compound, the amount of free aromatic dihydroxy compound, By reducing the amount of free aromatic carbonic diester, it is possible to reduce the problems of corrosiveness and toxicity due to aromatic polycarbonate, burning during molding, reduction in molecular weight, and reduction in physical properties of molded products. As a physical method, the obtained aromatic polycarbonate is crushed with a grinder in a size of 2,000 μm or less, preferably 1000 μm or less, and practically 200 μm to 1000 μm.
μ and pulverized into a treatment tank maintained at a temperature of 80 ° C. or more and a temperature condition capable of maintaining the powder state.
The following is a method of treating for several hours in a high vacuum or a method of flowing an inert gas. Preferred temperatures are in the range from 80 ° C to 5 ° C below the glass transition temperature.

The amount of the free aromatic monohydroxy compound in the aromatic polycarbonate of the present invention is 30 ppm or less, preferably 10 ppm or less, more preferably 5 ppm or less.
In the following, it is preferable that the content is 1 ppm or less in a polycarbonate in which corrosiveness is a problem such as an optical disc application, and it is preferable that a polycarbonate in which a toxicity is a problem such as a food use essentially contains no free aromatic monohydroxy compound. .

The amount of the free aromatic dihydroxy compound in the aromatic polycarbonate of the present invention is 50 ppm or less, preferably 10 ppm or less, more preferably 5 pp.
m or less.

The amount of the free aromatic carbonic diester in the aromatic polycarbonate resin of the present invention is 50 ppm or less, preferably 10 ppm or less, more preferably 5 pp or less.
m or less. Since free aromatic carbonic diester generates phenol by hydrolysis, it is preferably 1 ppm or less for polycarbonates having a problem of corrosiveness such as optical disc applications, and free aromatic carbonates for polycarbonates having a problem of toxicity such as foods. Preferably, it is essentially free of diesters.

The amount of free aromatic monohydroxy compound, free aromatic dihydroxy compound and free aromatic carbonic diester can be controlled by the physical treatment time of the aromatic polycarbonate according to the present invention. Polycarbonates can also be produced. The aromatic polycarbonate thus obtained has a very small amount of free aromatic monohydroxy compound, free aromatic dihydroxy compound and free aromatic carbonate diester, and therefore has corrosiveness, toxicity, burning during molding, molecular weight reduction, molding. Shows characteristics with less problem of deterioration of physical properties of the product.

[0017]

EXAMPLES In the following examples, "%" and "parts" are "% by weight" or "parts by weight" unless otherwise specified. The viscosity average molecular weight is 0.7 g
/ Dl methylene chloride solution was measured for intrinsic viscosity using an Ubbelohde viscometer, and the viscosity average molecular weight was determined by the following equation. [Η] = 1.23 × 10 ⁻⁴ M ^0.83 The quantitative determination of the free aromatic monohydroxy compound, free aromatic dihydroxy compound and free aromatic carbonic acid diester of the aromatic polycarbonate was carried out by gas chromatography.

Example 1 In a reactor equipped with a stirrer and a distillation column, 1370 parts of 2,2-bis (4-hydroxyphenol) propane, 1350 parts of diphenyl carbonate, and bisphenol A as a catalyst were used.
0.016 parts of disodium salt was charged and the atmosphere was replaced with nitrogen. The mixture was heated to 160 ° C. and dissolved with stirring. Then, the degree of decompression was set to 30 mmHg and 200
C., and most of the phenol was distilled off in 1 hour. Then, the temperature was raised to 290 ° C., and the reaction was carried out at a reduced pressure of 1 mmHg for 0.5 hour to obtain a polycarbonate resin having a viscosity average molecular weight of 22,500. Its free phenol content was 10 ppm. Next, the pellets were pulverized to a shape of 500 μm, and 10 kg of the pulverized polycarbonate was charged into a treatment tank at 135 ° C. through which 50 L of dry nitrogen could flow per minute, and treated for 20 hours. No free phenol was detected in this, free 2,2-bis (4-hydroxyphenyl) propane was 10 ppm, and free diphenyl carbonate was 0.4 ppm.

Reference Example 1 Before the flow of dry nitrogen at 135 ° C., the polycarbonate contained 70 ppm of free phenol, 75 ppm of free 2,2-bis (4-hydroxyphenol) propane, and 90 ppm of free diphenyl carbonate.

[0020]

According to the present invention, a high-quality fragrance having reduced problems of toxicity, corrosiveness, burning during molding, reduction in molecular weight, and deterioration in physical properties of a molded product is obtained from an aromatic polycarbonate produced by a transesterification method. A group polycarbonate can be supplied.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-151304 (JP, A) JP-A-3-68627 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 64/00-64/42

Claims (2)

(57) [Claims] 1. An aromatic polycarbonate obtained by reacting an aromatic dihydroxy compound and an aromatic carbonic diester under heat and melting, in the form of powder having an average particle size of 2000 μ or less and maintaining the powder at 80 ° C. or more. (1) The content of the free aromatic monohydroxy compound is 30.
ppm or less, (2) the content of the free aromatic dihydroxy compound is 50 p
pm or less, and (3) the content of free aromatic carbonic diester is 50 ppm
The following method for producing an aromatic polycarbonate. 2. A aromatic polycarbonate obtained by an aromatic dihydroxy compound and an aromatic carbonic acid diester heat melting is lower reaction aromatic polycarbonate, the content of (1) free aromatic monohydroxy compound 30
ppm or less, (2) the content of the free aromatic dihydroxy compound is 50 p
pm or less, and (3) the content of free aromatic carbonic diester is 50 ppm
An aromatic polycarbonate characterized by the following.