JPS63223036A - Production of polycarbonate resin - Google Patents

Abstract

PURPOSE:To obtain the titled colorless resin having excellent transparency and suitable as a molding material for optical use, by reacting a dihydric phenol with a diaryl carbonate in the presence of a specific ester interchange catalyst. CONSTITUTION:The objective polycarbonate resin can be produced by mixing (A) a dihydric phenol [e.g. bis(4-hydroxyphenyl)methane] with preferably equimolar amount of (B) a diaryl carbonate (e.g. diphenyl carbonate), melting the mixture in an inert gas, adding preferably (C) metallic magnesium or a magnesium compound excluding halide and sulfate (e.g. magnesium oxide) to the molten mixture in an amount of 10<-6>-10<-1>mol.% based on the component A and reacting the components e.g. by raising the temperature to 250-300 deg.C under stirring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in a method for producing polycarbonate by transesterification.

More specifically, one or more metal magnesium or magnesium compounds (excluding halides and sulfates among magnesium compounds) are used as catalysts in the transesterification reaction of dihydric phenol and diaryl carbonate. The present invention relates to a method for producing a characteristic polycarbonate resin.

[Conventional technology and its problems]

Generally, the production of polycarbonate by transesterification of dihydric phenol and diaryl carbonate is carried out in the presence of a transesterification catalyst and in an inert gas such as nitrogen. First, heat the mixture to melt it, and then heat it to a temperature of 200 to 2
When the reaction is carried out at 30° C. and a pressure of 10 to 3 Qm+++)Ig, most of the phenol is distilled off. Further, when the temperature is increased to 270 to 300°C and the pressure is lowered to 1 mmftg or less, most of the phenol is removed and a high molecular weight polycarbonate is obtained.

However, the polycarbonate produced in this way was often colored pale yellow (Comparative Example 3), and it was difficult to obtain polycarbonate without coloring ("Plastic Materials Course ■ Polycarbonate Resin" P, 83 Nikkan Kogyo Shimbunsha) (1979)). Recently, a method has been proposed to reduce the coloring of polycarbonate resin by using iminocarboxylic acids or their metal salts as a catalyst (see Mitsubishi Kasei: Japanese Patent Publication No. 61-39972), but as shown in Comparative Example 2, However, the effect is not satisfactory.

[Means for solving problems]

The present inventors have conducted extensive research in order to find a catalyst that can synthesize a highly transparent polycarbonate resin without coloration in a method for producing polycarbonate resin using a transesterification method. It has been found that coloring of polycarbonate can be almost completely suppressed by reaction using a magnesium compound as a catalyst, excluding sulfate.

That is, in producing polycarbonate resin from dihydric phenol and diaryl carbonate by transesterification reaction, the present invention uses metallic magnesium or a magnesium compound (among magnesium compounds, excluding halides and sulfates) as a transesterification catalyst. 1
The present invention relates to a method for producing polycarbonate resin characterized by using one or more kinds of polycarbonate resins.

According to the production method of the present invention, a polycarbonate resin with excellent transparency and no coloration can be obtained.

[Structure of the invention]

The content of the present invention will be explained in detail below.

The dihydric phenols used in the practice of this invention are known dihydric phenols whose reactive groups are two phenolic hydroxyl groups.

Some of these are represented by general formulas. where A is a divalent hydrocarbon group containing 1 to about 15 carbon atoms: a substituted divalent hydrocarbon group containing 1 to about 15 carbon atoms, and halogen, -s -, -s
a substituent such as -s -, -s -, -5-111II -0- or -〇-, and each selected from the group consisting of hydrogen, an aryl group of 6 to 18 carbon atoms, an alkyl group of 7 to about 14 carbon atoms, an oxyalkyl group of 1 to about 8 carbon atoms, or an oxyaryl group of 6 to 18 carbon atoms. . m is 0 or 1.

Some representative examples of dihydric phenols that may be used in the practice of this invention include bisphenols such as bis(4-
hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane (also known as bisphenol A), 2,2-bis(4-hydroxy-3-
methylphenyl)propane, 4.4-bis(4-hydroxyphenyl)hebutane, 2.2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2.2-bis(4-hydroxy-3,5 -dibromophenyl)propane, etc.; dihydric phenol ethers such as bis(4-hydroxyphenyl)ether, bis(3,5-dichloro-
4-hydroxyphenyl) ether etc. Examples of dihydroxydiphenyl t jib, P'-dihydroxydiphenino to 3.3°-dichloro-4,4゛-dihydroxydiphenyl etc.; dihydroxyarylsulfones such as bis(
4-hydroxyphenyl) sulfone, bis(3,5-dimethyl-4-hydroxyphenyl) sulfone, etc.; dihydroxybenzene, halogen- and alkyl-substituted dihydroxybenzene, e.g., 1,4-dihydroxy-2,5-
dichlorobenzene, 1,4-dihydroxy-3-methylbenzene, etc.; dichlorobenzene, hydroxydiphenyl sulfide and sulfoxide such as bis(4-hydroxyphenyl) sulfide, dichlorobenzene (4-hydroxyphenyl) sulfoxide, bis(3,5-dibromo -4-hydroxyphenyl) sulfoxide and the like. Other dihydric phenols, such as U.S. Pat. No. 2,999,835, 30
Dihydric phenols described in No. 28365 and No. 3153008 are also available. Of course, two or more different dihydric phenols or a combination of dihydric phenols and glycols may also be used. Here, glycol is an aliphatic dihydric alcohol having 2 to 20 carbon atoms.

As the diaryl carbonate used in carrying out the present invention, those represented by the following general formula are used.

In the formula, Art and Ar2 may be the same or different. A "1, Ar2 is phenyl or alkylphenyl with a substituent such as methyl, ethyl, or propyl group, or phenoxyphenyl or aryl group with alkoxyphenynobephenoxy group having a substituent such as methoxy, ethoxy, or propoxy group. Represents arylphenyl having a substituent, or halogenated phenyl having a chlorine or bromine substituent.

Examples of the magnesium compound used in carrying out the present invention include magnesium oxide, magnesium hydroxide, alkylmagnesium, magnesium formate, magnesium acetate, magnesium carbonate, magnesium phosphate, magnesium hydride, phenoxymagnesium, and magnesium oxalate. Among these magnesium compounds and metallic magnesium, magnesium oxide, magnesium hydroxide, magnesium formate, and metallic magnesium are preferred.

In addition, since magnesium halides increase coloration, and magnesium sulfate has very low activity,
Each is not suitable as a catalyst (Comparative Example 1.4).

The amount of magnesium metal or magnesium compound used as a catalyst is about 10-6 to 10-1 mol%, preferably 10-4 to 10-2 mol%, based on the effective amount of bisphenol for a normal transesterification reaction. Ru. If the amount is too small, the catalytic effect will not be sufficient, and if the amount is too large, the coloring prevention effect will be reduced.

In order to produce polycarbonate resin by the method of the present invention, the conventionally known production method based on the transesterification reaction of dihydric phenol and diaryl carbonate can be applied almost as is.

For example, an equimolar mixture of bisphenol A and diphenyl carbonate, or a mixture using a slight excess of diphenyl carbonate, is heated and melted in air excluding oxygen or in an inert gas such as nitrogen, and metal magnesium and halides are melted. , a catalyst selected from magnesium compounds excluding sulfate groups is added. While stirring, the temperature is gradually raised to 250-300°C (preferably 260°C).
~280°C). On the other hand, the pressure is also gradually lowered and finally reduced to 1 mmHg or less, and the reaction is completed until a predetermined melt viscosity is reached.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained in detail with reference to Examples, but the present invention is not limited to these Examples.

Note that parts used in the examples are based on weight.

The methods for measuring the items used to evaluate the polycarbonate obtained according to the present invention are as follows.

(1) Evaluation method of viscosity average molecular weight: Intrinsic viscosity of methylene chloride solution at 20°C [η:l
(d/g) was measured using an Ubbelohde viscosity tube, and the viscosity average molecular weight was calculated using the following formula.

Iη] = 1.11X10-'(Mv)'-" (2)
Coloring evaluation method: A solution dissolved in methylene chloride at a concentration of 100 g/R was placed in a cell with an optical path length of 100 mm, and the absorbance at a wavelength of 350 nm to 600 nm was measured using a spectrophotometer. From the value of absorbance in nm 580 n
Coloring was evaluated by subtracting the absorbance value of m. The smaller the number, the less coloring.

Example 1 Bisphenol A183 was added to a reactor equipped with a stirrer and replaced with nitrogen.
and 180 parts of diphenyl carbonate, and heated to 160°C.
After melting, magnesium hydroxide was added as a catalyst in an amount of 1×10 −3 mol % based on bisphenol A to start the reaction. The temperature was gradually raised to 270° C. over 3 hours and 30 minutes, and the reaction system pressure was reduced to 1QnnmHg to distill off the produced phenol. Continue to heat at 270°C for 2 hours.
The reaction was carried out at 15 to 0.10 mmHg to obtain a polymer.

The obtained polymer was free from coloration, had excellent transparency, and had a viscosity average molecular weight of 20,400.

The results of evaluation of the coloring of the obtained polymers are shown in Table 1 and FIG.

Example 2 Bisphenol A183 was added to a reactor equipped with a stirrer and replaced with nitrogen.
and 180 parts of diphenyl carbonate, and heated to 160°C.
After melting, magnesium oxide was added as a catalyst in 1X10-'' mol% based on bisphenol A, and the reaction was started.The temperature was gradually raised to 270°C over 4 hours, and the reaction system pressure was reduced to 1QmmHg. The phenol that
The reaction was carried out at 0 mmHg to obtain a polymer, which had no coloration, excellent transparency, and a viscosity average molecular weight of 17.
It was 700.

The results of evaluation of the coloring of the obtained polymers are shown in Table 1 and FIG.

Example 3 Bisphenol A183 was added to a reactor equipped with a stirrer and replaced with nitrogen.
and 180 parts of diphenyl carbonate, and heated to 160°C.
After melting, magnesium formate was added as a catalyst in an amount of 0-3 mol % based on bisphenol A, and the reaction was started. The temperature was gradually raised to 270° C. over 4 hours and 50 minutes, and the reaction system pressure was also reduced to IQ mmHg to distill off the produced phenol.

Continued at 270℃ for 2 hours 0.15-0.10+nmH
g to obtain a polymer. The obtained polymer was free from coloration, had excellent transparency, and had a viscosity average molecular weight of 14,500.

The results of evaluation of the coloring of the obtained polymers are shown in Table 1 and FIG.

Example 4 Bisphenol A183 was added to a reactor equipped with a stirrer and replaced with nitrogen.
and 180 parts of diphenyl carbonate, and heated to 160°C.
After melting, 2.9 x 10-3 mol% of magnesium metal was added to bisphenol A as a catalyst to start the reaction. The temperature was gradually raised to 270°C over 4 hours, and the reaction system pressure was reduced to 1QmmHg to distill off the produced phenol.

Continue to 0.15-0.10mmHg at 270℃ for 2 hours
The reaction was carried out to obtain a polymer. The obtained polymer was free from coloration, had excellent transparency, and had a viscosity average molecular weight of 16,500.

The results of evaluation of the coloring of the obtained polymers are shown in Table 1 and FIG.

In Examples 1 to 4 showing the implementation details of the present invention, the value of As5o As8a indicating coloration (the value obtained by subtracting the absorbance value at 580 nm from the value of absorbance at 380 nm) was 0.087 at maximum and 0.073 at minimum. It has become.

Comparative Example 1 Bisphenol A183 was added to a reactor equipped with a stirrer and replaced with nitrogen.
and 180 parts of diphenyl carbonate, and heated to 160°C.
After melting, magnesium chloride was added as a catalyst in an amount of 0-' mole % based on bisphenol A, and the reaction was started. The temperature was gradually raised to 270° C. over 3 hours, and the reaction system pressure was reduced to 1 Q mmHg to distill off the produced phenol. Continue to heat at 270°C for 2 hours at 0.15~0.
A polymer was obtained by reacting at 10+nmHg. The viscosity average molecular weight of the obtained polymer was 20,300.

The results of evaluation of the coloring of the obtained polymers are shown in Table 1 and FIG.

Comparative Example 2 In place of the catalyst of Comparative Example 1, 2) IJ7 trisodium triacetate based on bisphenol A I
The reaction was carried out in the same manner as in Comparative Example 1 except for the addition.

The results of evaluation of the coloring of the obtained polymers are shown in Table 1 and FIG.

Comparative Example 3 Bisphenol A183 was added to a reactor equipped with a stirrer and replaced with nitrogen.
and 180 parts of diphenyl carbonate, and heated to 160°C.
After melting, sodium hydroxide was added as a catalyst in an amount of 1X10-3 mol % based on bisphenol A to start the reaction. The temperature was gradually raised to 270°C over 3 hours, and the reaction system pressure was reduced to 1QmmHg to distill off the produced phenol. 0.15~0 for 40 minutes at 270℃
．． The reaction was carried out at 10 mmHg to obtain a polymer. The viscosity average molecular weight of the obtained polymer was 15,500.

In Comparative Examples 1, 2, and 3, the value of A38[I A3110 is larger than that of the example of the present invention.

Comparative Example 4 Bisphenol A183 was added to a reactor equipped with a stirrer and replaced with nitrogen.
and 180 parts of diphenyl carbonate, and heated to 160°C.
After melting, magnesium sulfate is added as a catalyst in an amount of 4×10 −3 mol % based on bisphenol A to start the reaction. Even when the pressure was reduced to 50 Torr and the temperature was raised to 220° C., very little phenol was distilled out, and the reaction was discontinued.

Table 1 [Effects of the Invention] From FIG. 1, it can be seen that the slopes of the absorbance curves of Examples 1 to 4 are smaller than the slopes of the absorbance curves of Comparative Examples 1 to 3. From this, it can be seen that the polycarbonate resin obtained in the example has less coloring.

The polycarbonate resin obtained from the present invention is a polycarbonate resin with excellent transparency and non-coloring properties.
It is particularly useful as an optical molding material.

[Brief explanation of the drawing]

FIG. 1 illustrates absorbance curves in the range of 350 nm to 600 nm in the coloring evaluation tests of Examples 1 to 4 and Comparative Examples 1 to 30.

Claims (1)

[Claims] In producing polycarbonate from dihydric phenol and diaryl carbonate by transesterification,
As a transesterification catalyst, metallic magnesium or
A method for producing a polycarbonate resin, which comprises using one or more magnesium compounds (excluding halides and sulfates among magnesium compounds).