JPH05148353A - Production of polycarbonate - Google Patents

Abstract

PURPOSE:To produce a colorless transparent high-molecular polycarbonate industrially at high efficiency by effecting the melt polycondensation of a dihydroxy compound with a bisaryl carbonate by transesterification. CONSTITUTION:The above transesterification is performed in a reaction apparatus made of a ceramics. A colorless transparent high-molecular polycarbonate can be produced and can find a use where it can fully exhibit its transparency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polycarbonate, and more particularly to a method for producing a polycarbonate which is colorless and transparent and has a high molecular weight.

[0002]

BACKGROUND OF THE INVENTION Polycarbonates are versatile engineering thermoplastics having a wide range of applications, especially for injection molding or as sheet glass alternatives to glazings.

Conventionally, an interfacial polycondensation method, a transesterification method and the like have been applied to the production of these polycarbonates.
The interfacial polycondensation method is generally effective in producing polycarbonate, but has drawbacks such as the use of toxic phosgene and the fact that chlorine ions remain in the polycarbonate produced.

In order to solve these drawbacks, a method for producing a polycarbonate by using an interfacial polycondensation reaction with a special dihydric phenol using liquid trichloromethyl chloroformate which is a dimer of phosgene instead of toxic phosgene. Is disclosed in JP-A-63-182336.

However, there is only a description of 9,9-bis (4-hydroxyphenyl) fluorenes as a special dihydric phenol. Also, triphosgene was used in place of toxic phosgene, and 2,2-bis (4
-Hydroxyphenyl) propane to obtain polycarbonate is described in Angew. Chem. (Angevante.
Chemie) 99.922 (1987), German patent DE3
Although described in the specification of 440141, a reaction mechanism in which phosgene is generated is also proposed.

In the transesterification reaction, a transesterification catalyst is added to diphenyl carbonate and an aromatic dihydroxy compound to synthesize a prepolymer while distilling phenol under heating and reduced pressure, and finally under high vacuum, 290
High-molecular-weight polycarbonate is obtained by distilling phenol by heating above ℃ (US Pat. No. 4,345,062).
However, unlike other engineering plastics, high molecular weight polycarbonate requires a high temperature of 290 ° C. or higher as a reaction condition because it has a very high melt viscosity, and in order to distill off phenol having a high boiling point. Since it requires a high vacuum (10 ^-2 Torr), it is known that industrialization is difficult from the viewpoint of equipment and there are problems in hue and physical properties.

However, the transesterification method has been studied variously because it can perform the reaction by melt polycondensation and is an industrially economical method.
In particular, the influence of the material of the reactor is suggested from the viewpoint of product coloring, and as described in JP-A-55-142025, the polycarbonate obtained is colored when a stainless reactor is used. In many cases, it is difficult to obtain a high molecular weight product, which suggests that it is difficult to produce a product having satisfactory physical properties and hue. Further, although a special catalyst has been found out by studying various catalysts, it was not always satisfactory.
Further, although it is different from the starting material of the present invention, US Pat. No. 4,383,092 also describes the material related to the reactor.

[0008]

Means for Solving the Problems The inventors of the present invention have earnestly studied high molecular weight and resin coloring, which are one of the problems in the transesterification method conventionally used for the production of polycarbonate. As a result, the fact that a colorless and transparent high-molecular-weight polycarbonate can be obtained by using a special material for the liquid contact portion has been completed, and the present invention has been completed.

That is, according to the present invention, in a method for producing a polycarbonate by melt polycondensation of a divalent hydroxy compound and a bisaryl carbonate by a transesterification method in the presence of a transesterification catalyst, ceramics is used as a material of a reactor. A method for producing a polycarbonate for obtaining a high molecular weight colorless transparent resin.

Further details will be described. In the present invention, it has been found that a high-molecular-weight, colorless and transparent polycarbonate can be obtained by using ceramics, particularly preferably nitride-based ceramics, as the material of the reactor or the material of the portion in contact with the polycarbonate reactant.

Typical ceramics used in the present invention include aluminum oxide, magnesium oxide, spinel, beryllium oxide, partially stabilized zirconia, zirconia toughened alumina, cordierite, aluminum titanate, mullite, titanium oxide, Oxide ceramics such as tin oxide, thorium oxide and chromium oxide, nitride ceramics such as silicon nitride, boron nitride, aluminum nitride, titanium nitride, zirconium nitride, hafnium nitride and sialon, and carbides such as silicon carbide, boron carbide and tungsten carbide. Ceramics, chemical stoneware, chemical porcelain, high refractory porcelain, silicate ceramics such as crystallized glass, amorphous carbon, carbon materials such as hexagonal graphite, boride ceramics such as titanium boride, molybdenum silicide Silicide ceramics, etc. Etc. The. Particularly preferably, nitride-based ceramics are mentioned as the material inert to the reaction.

Typical examples of the transesterification catalyst that can be used in the present invention include (a) a catalyst containing a metal-containing catalyst: 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, Tetraphenoxy lithium, tetraphenoxy sodium, tetraphenoxy potassium, tetraphenoxy rubidium, tetraphenoxy cesium, sodium thiosulfate, beryllium oxide, magnesium oxide, tin oxide (tetravalent), dibutyltin oxide, beryllium hydroxide, magnesium hydroxide, hydroxide Germanium, beryllium acetate, magnesium acetate, tin acetate (tetravalent), germanium acetate, lithium carbonate, sodium carbonate, potassium carbonate, beryllium carbonate, magnesium carbonate Um, tin carbonate (tetravalent), carbonate germanium, tin nitrate (tetravalent), germanium nitrate, antimony trioxide, bismuth trimethyl carboxylate.

(B) As a catalyst similar to the electron-donating amine compound, 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, imidazole, 2-methylimidazole,
4-methylimidazole, diazabicyclooctane (D
ABCO) and the like.

Further, (c) carbonic acid, acetic acid, formic acid, nitric acid, nitrous acid, oxalic acid, fluoroboric acid, hydrofluoric acid salt and the like of the above-mentioned electron donating amine compound may be mentioned. (D) As a catalyst similar to the electron-donating phosphorus compound, triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tri-o-dimethoxyphenylphosphine, tri-p -Tolylphosphine, tri-o-tolylphosphine, tributylphosphite, triphenylphosphite, tri-p-tolylphosphite, tri-o-tolylphosphite and the like can be mentioned.

Further, as a catalyst similar to borane complex (e), a complex of borane and the following compounds, that is, ammonia, dimethylamine, trimethylamine, triethylamine, t-butylamine, dimethylaniline, pyridine, dimethylaminopyridine, morpholine, Examples thereof include complexes such as piperazine, pyrrole, tetrahydrofuran, dimethyl sulfide, tri-n-butylphosphine, triphenylphosphine and triphenylphosphite. Particularly preferred transesterification catalysts include electron-donating amine compounds or a combination of electron-donating amine compounds with alkali metal compounds or alkaline earth metal compounds.

Examples of the divalent hydroxy compound used in the present invention include compounds represented by Chemical formulas 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-triphenylethane, 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) -Sec. 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-hydroxyphenyl) -m-diisopropylbenzene,
1,1-bis- (4-hydroxyphenyl) cyclohexane etc. are mentioned. Furthermore, it is also possible to produce a copolycarbonate by combining two or more divalent hydroxy compounds.

Examples of the bisaryl carbonate include diphenyl carbonate, bis (2,4-dichlorophenyl) carbonate, bis (2,4,6-trichlorophenyl) carbonate, bis (2-cyanophenyl) carbonate, and bis (o-carbonate). Nitrophenyl) carbonate,
Examples thereof include ditolyl carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate and the like. Diphenyl carbonate is preferred.

The production method of the present invention comprises 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 above-mentioned transesterification catalysts. Carried out by

The temperature at which this reaction proceeds is from 100 ° C to about 30 ° C.
The range is up to 0 ° C. The reaction temperature is preferably in the range of 130 ° C to 280 ° C. Reaction temperature is 130 ℃
If it is lower than 280 ° C., the reaction rate becomes slow, and if it exceeds 280 ° C., a side reaction easily occurs. The at least one compound selected as a catalyst requires 10 ^-1 mol to 10 ^-5 mol, preferably 10 ^-2 mol to 10 mol, based on the divalent hydroxy compound present in the reaction system. ^-4 mol. When the amount of the catalyst is less than 10 ^-5 mol, the catalytic action is small and the polymerization rate of the polycarbonate is slow, and when the amount of the catalyst is 10 ^-1 mol or more, the rate of remaining in the generated polycarbonate is high, and therefore the polycarbonate is Cause deterioration of physical properties of.

The required amount of bisaryl carbonate is equimolar to the divalent hydroxy compound present in the reaction system. In general, 1 mol of a carbonate compound and 1 mol of a divalent hydroxy compound must react to form a high molecular weight polycarbonate. However, industrially, bisaryl carbonate has conventionally been treated with an excess of 1.00 to 1.10 mol of bisaryl carbonate with respect to the hydroxy compound, which is included as a condition of the present invention.

The present invention also includes the case where the above substances are used as the surface material.

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

[0023]

[Example 1] Aluminum oxide (Al ₂ O ₃ ) was sprayed onto a reaction vessel coated with ceramics to form a coating layer 2, 2.
22.8 g of -bis (4-hydroxyphenyl) propane
(0.1 mol), 2-methylimidazole 0.0164
g (2 × 10 ^-4 mol) and bisphenyl carbonate 2
1.9 g (0.1023 mol) was added and under nitrogen atmosphere 1
After stirring for 1 hour at 80 ° C., the temperature is gradually reduced while heating,
Finally, a polycondensation reaction was carried out at 0.1 Torr and 270 ° C. for 2 hours, and the produced phenol was distilled off to obtain a colorless transparent polycarbonate. When the viscosity average molecular weight (Mv) of the obtained polycarbonate was measured, it was Mv = 30,500. Further, the hue was A ₃₈₀ -A ₅₈₀ = 0.07.

The method of measuring the viscosity average molecular weight is 2
The intrinsic viscosity [η] of the methylene chloride solution at 0 ° C. was measured using an Ubbelohde viscometer, and the viscosity average molecular weight (Mv) was calculated using the following formula. [Η] = 1.11 × 10 ⁻⁴ (Mv) ^{0.82 Further} , the hue was evaluated by using a 10% methylene chloride solution of polycarbonate with a UV measuring device at 380 nm and 580 n.
The difference in absorbance in the wavelength region of m was measured and displayed, and the larger the value, the more the coloring.

[0025]

Example 2 Using a reaction vessel coated with ceramics by spraying boron nitride (BN), 0.0061 g (5 × 10 ⁻⁵ mol) of 4-dimethylaminopyridine was used as an ester exchange catalyst instead of 2-methylimidazole. )
The same reaction as in Example 1 was carried out except that was used to obtain a polycarbonate. The viscosity average molecular weight (Mv) of the obtained polycarbonate was Mv = 34,000. Further, the hue was A _{38 0} -A ₅₈₀ = 0.06.

[0026]

Example 3 Using a reaction vessel coated with ceramics by spraying silicon carbide (SiC), a reaction was carried out with the same formulation as in Example 2. When the viscosity average molecular weight (Mv) of the obtained polycarbonate is measured, Mv = 30,9
It was 00. Further, the hue is A ₃₈₀ −A ₅₈₀ = 0.1
It was 0.

[0027]

Example 4 Using a reaction vessel coated with ceramics by spraying zirconium oxide (ZrO ₂ ), a reaction was carried out with the same formulation as in Example 2. When the viscosity average molecular weight (Mv) of the obtained polycarbonate is measured, Mv =
It was 31,500. Also, the hue is A ₃₈₀ -A ₅₈₀
= 0.09.

[0028]

Example 5 Using a reaction vessel coated with ceramics by spraying silicon nitride (Si ₃ N ₄ ), a reaction was carried out with the same formulation as in Example 2. When the viscosity average molecular weight (Mv) of the obtained polycarbonate is measured, Mv = 3
It was 5,600. Further, the hue is A ₃₈₀ −A ₅₈₀ =
It was 0.05.

[0029]

Example 6 The same method as in Example 2 except that 0.0061 g (5 × 10 ⁻⁵ mol) of 4-dimethylaminopyridine and 0.00049 g (10 ⁻⁶ mol) of potassium acetate were used together as the transesterification catalyst. I went. When the viscosity average molecular weight (Mv) of the obtained polycarbonate is measured, Mv =
It was 38,500. In addition, hue, A ₃₈₀ -A _{58 0}
= 0.06.

[0030]

[Comparative Example 1] Stainless steel (SUS316: Fe 67
%, Cr 18%, Ni 12%, Mo 25%, C
0.06%) was used for the reaction in the same manner as in Example 2 to obtain a polycarbonate. When the viscosity average molecular weight (Mv) of the obtained polycarbonate is measured, it is M
v = 18,000. The hue is A ₃₈₀ -A
₅₈₀ = 0.319.

[0031]

Comparative Example 2 Stainless steel (SUS304: Fe 74
%, Cr 18%, Ni 8%, C 0.06%) was used to carry out the reaction in the same manner as in Example 2 to obtain a polycarbonate. When the viscosity average molecular weight (Mv) of the obtained polycarbonate was measured, it was Mv = 17,000. Moreover, the hue was A ₃₈₀ −A ₅₈₀ = 0.354.

[0032]

Comparative Example 3 A reaction vessel made of carbon steel (SS-41) was used to carry out the reaction in the same manner as in Example 2 to obtain a polycarbonate. When the viscosity average molecular weight (Mv) of the obtained polycarbonate was measured, it was Mv = 14,300. Moreover, the hue was A ₃₈₀ −A ₅₈₀ = 0.429.

[0033]

According to the present invention, a colorless and transparent polycarbonate having a high molecular weight and no coloration can be obtained.

Claims (5)

[Claims] 1. A method for producing a polycarbonate by melt-polycondensing a divalent hydroxy compound and a bisaryl carbonate by a transesterification method in the presence of a transesterification catalyst, wherein a transesterification reaction is carried out by using ceramics as a material of a reaction apparatus. A method for producing a polycarbonate, which comprises: 2. A composition according to claim 1, wherein in the method for producing a polycarbonate by melt polycondensation of a divalent hydroxy compound and a bisaryl carbonate by a transesterification method in the presence of a transesterification catalyst, the material which comes into contact with the reactant is a composition. A method for producing a polycarbonate, comprising: 3. The method for producing a polycarbonate according to claim 1, wherein the ceramic is a nitride. 4. The method for producing a polycarbonate according to claim 1, wherein the transesterification catalyst comprises an electron-donating amine compound or an electron-donating amine compound in combination with an alkali metal compound or an alkaline earth metal compound. 5. A divalent hydroxy compound is represented by the following chemical formulas 1, 2, 3
The method for producing a polycarbonate according to claim 1, wherein the compound is represented by 4 or 4. [Chemical 1] [Chemical 2] [Chemical 3] [Chemical 4] (R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each a hydrogen atom,
Represents 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 and m = 1-4. )