JPH0488017A - Production of polycarbonate - Google Patents

Abstract

PURPOSE:To obtain the subject high-molecular weight colorless and transparent polycarbonate suitable for injection molding by carrying out ester interchange reaction using a material having a specific content or below of iron as a material for a reactor. CONSTITUTION:(A) A dihydric hydroxy compound and (B) a bisaryl carbonate are subjected melt polymerization in the presence of an ester interchange catalyst according to an ester interchange method. In the process, a material (e.g. Monel metal) with <=20% iron content is used as a material for a reactor to carry out ester interchange reaction. Thereby, the objective polycarbonate is obtained. Furthermore, the component (A) is preferably a compound expressed by formula I to IV (R1 to R5 are H, 1-8C alkyl or phenyl; X is halogen; n is 0-4; m is 1-4).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing polycarbonate, and more particularly to a method for producing polycarbonate that yields a high molecular weight polycarbonate with little coloring.

BACKGROUND OF THE INVENTION Polycarbonate is a general purpose engineering thermoplastic that has a wide range of uses, particularly for injection molding or as glass sheets in place of window panes.

Conventionally, interfacial polycondensation methods, transesterification methods, and the like have been applied to the production of these polycarbonates.

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, a method for manufacturing polycarbonate by using liquid trichloromethyl chloroformate, which is a dimer of phosgene, instead of toxic phosgene, and carrying out an interfacial polycondensation reaction with a special dihydric phenol has been disclosed. It is disclosed in Publication No. 182336/1983. However, as a special dihydric phenol, 9
, 9-bis(4-hydroxyphenyl)fluorenes. In addition, a method for obtaining polycarbonate from 2,2-bis(4-hydroxyphenyl)propane using triphosgene instead of toxic phosgene is described in Angew, Chem, (Angevante,
922 (1987), German Patent D
Although described in the specification of E3440141, a reaction mechanism in which phosgene is generated has also been proposed.

In the transesterification reaction, a transesterification catalyst is added to diphenyl carbonate and an aromatic dihydroxy compound, and a prepolymer is synthesized while distilling phenol under heating and reduced pressure.Finally, the prepolymer is heated to 290°C or higher under high vacuum. High molecular weight polycarbonate is obtained by distilling phenol out (U.S. Pat. No. 4,345,062), but unlike engineering plastinox, other high molecular weight polycarbonates have extremely high melt viscosity, so the reaction conditions are Requires high temperatures of 290°C or higher,
In addition, high vacuum (10-2 Torr) is required to distill off phenol, which has a high boiling point, making industrialization difficult in terms of equipment.Furthermore, phenol remains in the polycarbonate produced, resulting in poor color and physical properties. It is known to have undesirable effects.

However, since the transesterification method can carry out the reaction by melt polycondensation and is an industrially economical method, various studies have been made. In particular, the influence of the material of the reactor has been suggested from the viewpoint of product coloring. For example, although the material is different from the starting material of the present invention,
It has been proposed to prevent product coloring by using tantalum, nickel or chromium as the reactor material, as disclosed in US Pat. No. 3,830,092.

However, these metals are expensive and impractical to use as reactor materials. Furthermore, the present inventors found that when carbon steel or stainless steel is used as is when producing polycarbonate by the transesterification method in the presence of a transesterification catalyst, the molecular weight cannot be increased and the reproducibility of the molecular weight is poor. Met. Furthermore, the resin was significantly colored.

(Means for Solving the Problems) As a result of intensive research on increasing the molecular weight and coloring of resins, which are one of the problems of the transesterification method conventionally used in the production of carbonate, the present inventors found that the material of the reaction equipment As a result, the present inventors have discovered that a high molecular weight polycarbonate can be obtained by using a material with a low iron content especially in the liquid contact parts, and have completed the present invention.

That is, the present invention provides a method for producing polycarbonate by melt polycondensing a divalent hydroxy compound and a bisaryl carbonate by a transesterification method in the presence of a transesterification catalyst. The present invention provides a polycarbonate manufacturing method for obtaining a high molecular weight, colorless and transparent resin by using materials containing few or almost no components.

Typical examples of transesterification catalysts that can be used in the present invention include (a) catalysts similar to metal-containing catalysts such as lithium borohydride, sodium borohydride, potassium borohydride, rubidium borohydride, Cesium borohydride, beryllium borohydride, magnesium borohydride, calcium borohydride, strontium borohydride, barium borohydride, aluminum borohydride, titanium borohydride, tin borohydride, germanium borohydride, Lithium tetraphenoxy, sodium tetraphenoxy, potassium tetraphenoxy, tetraphenoxylbidium, tetraphenoxycesium, sodium thiosulfate, beryllium oxide, magnesium oxide, tin oxide (IV
), dibutyltin oxide, beryllium hydroxide, magnesium hydroxide, germanium hydroxide, beryllium acetate,
Magnesium acetate, tin (IV) acetate, germanium acetate, lithium carbonate, sodium carbonate, potassium carbonate, beryllium carbonate, magnesium carbonate, tin (IV) carbonate,
Examples include germanium carbonate, tin (IV) nitrate, germanium nitrate, antimony trioxide, bismuth trimethyl carboxylate, and the like.

(b) Catalysts similar to electron-donating amine compounds include:
N,N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 4-aminopyridine, 2-aminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 4-hydroxypyridine, 2
-dimethylaminoimidazole, 2-methoxyimidazole, 2-mercaptoimidazole, aminoquinoline,
Examples include imidazole, 2-methylimidazole, 4-methylimidazole, diazabicyclooctane (DABCO), and the like.

Further, (c) carbonic acid, acetic acid, formic acid, nitric acid, nitrous acid, oxalic acid, fluoroboric acid, hydrofluoride, etc. of the above-mentioned electron-donating amine compounds can be mentioned.

(d) As a catalyst similar to an electron-donating phosphorus compound, triethylphosphine, tri-n-propylphosphine,
triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tri-〇-dimethoxyphenylphosphine, tri-p-tolylphosphine, tri-〇-)lylphosphine, tributylphosphine,
Examples include triphenyl phosphite, tri-p-tolyl phosphite, tri-o-tolyl phosphite, and the like.

Furthermore, (e) catalysts similar to borane complexes include complexes of borane and the following compounds, namely ammonia, dimethylamine, trimethylamine, triethylamine, t-
Butylamine, dimethylaniline, pyridine, dimethylaminopyridine, morpholine, piperazine, pyrrole,
Tetrahydrofuran, dimethyl sulfide, tri-n-
Examples include complexes of butylphosphine, triphenylphosphine, triphenylphosphite, and the like.

Furthermore, examples of the divalent hydroxy compound used in the present invention include compounds represented by the following general formulas (I) to (IV).

(In the formula, R1, R2, Ra, R4, and R5 each represent a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a phenyl group, X represents a halogen atom, and n = 0 to 4. m = 1 to 4.) Specifically, 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-dibromo-4-hydroxyphenyl)propane, 2,2-bis-(4-hydroxy-3-methylphenyl)propane, 2,2-bis-(
4-hydroxy-3-isopropylphenyl)propane, 2,2-bis-(4-hydroxy-3-see, butylphenyl)propane, 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)propane , 2.2-bis-(4-hydroxy-3-tert-butylphenyl)propane, 1.1'-bis-(4-hydroxyphenyl)-p-diisopropylbenzene, 1,1'-bis-(4- Examples include hydroxyphenyl)-m-diisopropylbenzene, 1,1-bis-(4-hydroxyphenyl)cyclohexane, and the like. Furthermore, it is also possible to produce a copolymerized polycarbonate by combining two or more of these divalent hydroxy compounds.

The production method of the present invention is carried out by subjecting a divalent hydroxy compound such as bisphenol A to a melt polycondensation reaction with a bisaryl carbonate such as bisphenyl carbonate using at least one of the transesterification catalysts shown above. Ru.

The temperature at which this reaction proceeds ranges from 100°C to about 300'C. The reaction temperature is preferably 130
It ranges from °C to 280 °C. Reaction temperature is 130°
When it is less than C, the reaction rate becomes slow, and when it exceeds 28o0C, side reactions tend to occur.

At least one compound selected as a catalyst has a 10-
1 mole to 10-5 mole is required, preferably 1 mole.
The amount ranges from 0-2 mol to 10-4 mol. Catalyst amount is 10-5
If the amount is less than 1 mol, the catalytic effect will be low and the polymerization rate of the polycarbonate will be slow, and if the amount is 10 -1 mol or more, the proportion of polycarbonate remaining as a catalyst will be high, leading to a decrease in the physical properties of the polycarbonate.

Further, the required amount of bisaryl carbonate is equivalent to the molar amount of the divalent hydroxy compound 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 a divalent hydroxy compound must react. If bisaryl carbonate is used, 2 moles of hydroxy compound are produced by the reaction. These 2 moles of hydroxy compound are distilled out of the reaction system. However, industrially, bisaryl carbonate has traditionally been used at a ratio of 1 to 1 for hydroxy compounds.
．． 00 to 1.10 moles of bisaryl carbonate excess, which is included as a condition of the present invention.

Although the mechanism of the production method of the present invention is not necessarily clear, when a material containing a large amount of iron is used in the reaction equipment, especially in the wetted parts, the interaction between the iron component and the transesterification catalyst, and the reaction system By promoting thermal decomposition and side reactions at high temperatures due to interaction with
It is thought that the increase in molecular weight is suppressed or the resin is colored. The material of the reactor used in the present invention has an iron content of 20% or less, and includes, for example, Monel, Hastelloy, Inconel, and the like. In particular, Monel (
Ni-Cu alloy) is preferred. The present invention also includes laminated materials or plated materials using the above substances as surface materials.

The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

(Example) Example 1 Monel 400 (Ni 66.5%, Cu 31.5%, F
22.8 g (0.1 mol) of 2,2-bis(4-hydroxyphenyl)propane, 0.164 g (2X 10' mol) of 2-methylimidazole and 21 .9g (0,102
After stirring at 180°C for 1 hour under a nitrogen atmosphere, the temperature was gradually increased while reducing the pressure until the final temperature was 0.1T.
A polycondensation reaction was carried out at 270° C. for 2 hours, and the produced phenol was distilled off to obtain a colorless and transparent polycarbonate.

When the viscosity average molecular weight (Mv) of the obtained polycarbonate was measured, Wiv=28. ooo Tea Tsuta. The hue was A38O-A580=0.110.

Here, the viscosity average molecular weight is measured by measuring the intrinsic viscosity [Tl] of a methylene chloride solution at 20°C using an Ubbelohde viscometer, and using the following formula to calculate the viscosity average molecular weight (M
v) was calculated.

-14=[11]=1.11X10-'(Mv)0-"2Also,
Hue evaluation was performed by measuring and displaying the difference in absorbance in the wavelength range of 380 μm and 580 pm using a UV measurement device using a 10% methylene chloride solution of polycarbonate.
The larger the value, the more colored it is.

Example 2 The same procedure as in Example 1 was carried out, except that a reaction vessel made of Monel 400 was used and 0.0122 g (I x 10'mol) of 4-dimethylaminopyridine was used as the transesterification catalyst instead of 2-methylimidazole. The reaction was carried out to obtain polycarbonate.

The viscosity average molecular weight (Mv) of the obtained polycarbonate was measured and found to be 30,800. Further, the hue was A38O-A580=0.108.

Example 3 Inconel 600 (Ni 76%, Cr 15.5%,
Polycarbonate was obtained by carrying out a reaction in the same manner as in Example 2 using a reaction vessel made of Fe8%).

The viscosity average molecular weight (Mv) of the obtained polycarbonate was measured and found to be 29,700. Further, the hue was A38O-A580=0.110.

Example 4 Hastelloy B-2 (Ni 68%, Cr28%, Fe4
Polycarbonate was obtained by carrying out a reaction in the same manner as in Example 2 using a reaction vessel made by %).

The viscosity average molecular weight (Mv) of the obtained polycarbonate was measured and found to be Mv = 28,900. Also,
The hue was A38O-A580=0.105.

Comparative Example 1 Using a reaction vessel made of stainless steel (SUS316, iron content: 67%), a reaction was carried out in the same manner as in Example 2 to obtain polycarbonate.

The viscosity average molecular weight (Mv) of the obtained polycarbonate was measured and found to be 18,000. Further, the hue was A38O-A580=0.319.

Comparative Example 2 Using a reaction vessel made of stainless steel (SUS304, iron content: 74%), a reaction was carried out in the same manner as in Example 2 to obtain polycarbonate.

The viscosity average molecular weight (Mv) of the obtained polycarbonate was measured and found to be 21,400. Moreover, the hue was A380-A380=0.276.

Comparative Example 3 Using a reaction vessel made of carbon steel (88-41), a reaction was carried out in the same manner as in Example 2 to obtain polycarbonate.

The viscosity average molecular weight (Mv) of the obtained polycarbonate was measured and found to be 14,300. Further, the hue was A380-A380: 0.283.

(Effects of the Invention) According to the present invention, a colorless and transparent polycarbonate having a high molecular weight and no coloring can be obtained.

Patent applicant Daicel Chemical Industries, Ltd. procedural amendment (
Spontaneous) Q. 26, 1991 1990 Patent Application No. 204394/2, Title of invention: Process for manufacturing polycarbonate 3, Relationship with the case of the person making the amendment Patent applicant address: 1 Teppo-cho, Sakai City, Osaka Prefecture [Detailed Description of the Invention Column] 5. Contents of Amendment (1) Specification, page 13, line 17 [... Inconel etc. are listed. Next to J [Others include glass lining, ceramics, etc. Here, ceramics refers to heat-resistant nonmetallic inorganic materials such as oxides, carbides, nitrides, and sulfides. ” to join.

Island visitor (77ゝ8, '11

Claims (2)

[Claims] (1) A method for producing polycarbonate by melt polycondensing a divalent hydroxy compound and a bisaryl carbonate by a transesterification method in the presence of a transesterification catalyst, using a material containing 20% or less iron as the material for the reaction equipment. A method for producing polycarbonate characterized by carrying out a transesterification reaction. (2) The divalent hydroxy compound has the following general formula (I), (
The method for producing polycarbonate according to claim 1, which is a compound represented by II), (III) or (IV). ▲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) (In the formula, R_1, R_2, R_3, R_4, and R_5 each represent a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a phenyl group, X represents a halogen atom, and n=0 ~4, m=1~4.)