JPH02166119A - Production of aromatic polycarbonate - Google Patents

Abstract

PURPOSE:To obtain the title polycarbonate by a relatively simple operation without using toxic phosgene by reacting a dialkyl carbonate with a bisphenol A bisacetate and phenyl acetate in the presence of a specified transesterification catalyst. CONSTITUTION:A dialkyl carbonate of the formula: RO-CO-OR (wherein R is a 1-3C alkyl) is reacted with bisphenol A bisacetate and phenyl acetate in the presence of transesterification catalyst selected from an organotitanium (IV) compound (e.g. tetrabuthyl titanate) of the formula: TiX4 (wherein X is an alkoxy), the formula: TiOY2 (wherein Y is an alkyl or an acetylacetone) or the formula: TiX2Y2 and an organotin (IV) compound of the formula: (R')4-xSn(Z)x [wherein Z is -OCOR'' (wherein R'' is a 1-12C alkyl) or -OH; R' is R''; and x is 1-3] or the formula: R'-SnO-R' (wherein R' and R'' are each a 1-12C alkyl, a 6-12C aryl or -OH), e.g. monobutylmonohydroxytin oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention is directed to a novel method for producing aromatic polycarbonate resin. More specifically, the present invention provides a method for producing aromatic polycarbonate that does not use harmful phosgene gas in the polymer production process.

<Prior Art> Aromatic polycarbonate resins are engineering plastics with excellent mechanical and optical properties, and are widely used industrially as parts for electrical and electronic devices and optical disk materials.

Conventionally, as a manufacturing method for aromatic polycarbonate resin,
It is produced by a phosgene method in which raw material bisphenol-A and phosgene gas are directly reacted, or by a transesterification method between bisphenol-A and diallyl carbonate.

However, in the phosgene method, extremely toxic phosgene gas is used as a raw material, and a large amount of hydrochloric acid or common salt is produced as a by-product during the manufacturing process, so it requires an excessive amount of time and equipment to purify the polymer.

On the other hand, the transesterification method using diphenyl carbonate instead of phosgene has the same problems as the phosgene method because the raw material diphenyl carbonate is synthesized from phenol and phosgene.

For these reasons, a method has been proposed for producing aromatic polycarbonates by reacting dialkyl carbonates synthesized from aliphatic alcohols, carbon oxide, and air with bisphenol-A or its derivatives.

For example, JP-A-56-123949 describes a method for producing aromatic polycarbonate by reacting dialkyl carbonate with bisphenol-A-bisacetate.

Further, JP-A-157-2334 proposes a method for producing an aromatic polycarbonate by carrying out a polymerization reaction between a dialkyl carbonate and bisphenol A in the presence of phenol.

<Problems to be Solved by the Invention> In the method described in JP-A-56-123949, dialkyl carbonate and bisphenol-A-
The problem is that aromatic polycarbonate with a high degree of polymerization cannot be obtained because of poor reactivity with bisacetate.

On the other hand, the method proposed in JP-A No. 57-2334 is superior in that a polymer with a high degree of polymerization can be obtained, but the molecular chains of the polymer are branched, resulting in an abnormally high melt viscosity. It has problems such as poor fluidity and unsatisfactory impact resistance in terms of physical properties, and only aromatic polycarbonates with low commercial value have been obtained.

Therefore, an object of the present invention is to produce an aromatic polycarbonate with a high degree of polymerization and excellent impact resistance without using poisonous phosgene gas in the production process.

Means for Solving the Problems> The present inventors have arrived at the present invention as a result of intensive studies to solve the above-mentioned problems in producing aromatic polycarbonate.

That is, the present invention provides transesterification of the general formula RO-CO-OR-- (1 )
(In the formula, R represents an alkyl group having 1 to 3 carbon atoms.

The present invention provides a method for producing an aromatic polycarbonate, which comprises reacting a dialkyl carbonate represented by the following formula with bisphenol-A-bisacetate and phenylacetate.

The organic titanium (■) compound used in the present invention has the general formula TiXm (X represents an alkoxy group), or
Ti0Y2 (Y represents an alkyl group or an acetylacetone group), or TiX2Yp (X represents an alkoxy group, Y represents an alkyl group or an acetylacetone group)
It means an organic titanium (■) compound represented by
Specific examples include tetrabutyl titanate, tetraisopropyl titanate, tetraphenyl titanate, diacetylacetone titanium oxide, diacetylacetone dibutyl titanate, and the like.

Furthermore, the organotin (IV) compound used in the present invention has the general formula (R')a-xSn (Z))i (wherein Z
represents a -OH group. R' and R# are C
It represents a 1-C12 alkyl group, and X is an integer of 1-3. ), or R'-9nO-R" (wherein R'
and R# is a C1-C12 alkyl group, C1-C12
represents an aryl group or a 10H group. ), specifically, bis(tri-n-butyl)tin oxide, di-n-butyl
-butyltin oxide, monobutylmonohydroxytin oxide, di-n-butyltin dilaurate, tetra-n-butyltin, tetramethyltin, and tetraphenyltin.

Among these transesterification catalysts, titanate ester compounds and tin oxide compounds have high catalytic activity and are particularly preferably used. Further, these catalysts can be used alone, or two or more types of catalysts can be used without departing from the object of the present invention.

The amount of catalyst used in the present invention is as follows:
-diacetate) 0,001 to 100 parts by weight
5. 0! Amount part, preferably 0.01 to 1. Part by weight of O is suitable; if it is less than 0.001 part by weight, the catalyst activity is insufficient and a polymer with a high degree of polymerization cannot be obtained;
If the amount is more than 1 part by weight, the polymer may gel or become significantly colored, so it cannot be used.

Specific examples of the dialkyl carbonate represented by the general formula (I) used in the present invention include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, and the like. Among them,
From the viewpoint of polymerizability, dimethyl carbonate or diethyl carbonate is preferred, and dimethyl carbonate is particularly preferably used.

The addition amount of the dialkyl carbonate represented by the general formula (1) is suitably 1 to 5 mol per 1 mol of bisphenol-A-diacetate.

If the amount of dialkyl carbonate added is less than 1 mole, a polymer with a high degree of polymerization cannot be obtained. Furthermore, if the amount is 5 moles or more, the amount of recovered by-products increases, which is an economical problem.

The bisphenol-A-diacetate used in the present invention is a compound represented by the following structural formula. , without departing from the purpose of the present invention.

The phenylacetate used in the present invention can be used even if it contains phenol in part, and the amount of phenylacetate added is preferably 1 to 5 mol per 1 mol of dialkyl carbonate. If the amount of phenylacetate added is less than 1 mole, a polymer with a high degree of polymerization cannot be obtained, and if it is more than 5 moles, there is a problem in economic efficiency.

<Example> Next, the present invention will be explained with reference to Examples and Comparative Examples.

Example 1 70 g of bisphenol-A-diacetate,
38.3 g of dimethyl carbonate.

127.3 g of phenylacetate) and 0.070 g of tetrabutyl titanate were charged and stirred.

After replacing the inside of the reaction vessel with nitrogen, 10 kg/cm2
Pressure was applied. After raising the temperature to 220°C and reacting for 2 hours, the temperature was further raised to 240°C and transesterification was performed for 2 hours, and methyl acetate was distilled out from the top of the distillation column.

Subsequently, the reaction vessel was cooled and the contents were transferred to a vacuum polymerization apparatus equipped with a glass stirrer. While stirring the vacuum polymerization apparatus, the temperature was raised to 220° C. over 3 hours, and at the same time the pressure was gradually lowered to 1 mmHg. 220℃, lmmHg
The reaction was carried out for 1 hour, during which time excess dimethyl carbonate, phenylacetate and phenol were distilled off.

Furthermore, the reaction temperature was raised to 290° C. over 5 hours under reduced pressure, and the reaction was carried out at 290° C. for 2 hours to complete the polymerization.

η+nh of the obtained polycarbonate polymer is 0.6
1 (measured using tetrahydrofuran as a solvent and a 0.5% polymer solution at 25°C), and was transparent and pale yellow in color.

Next, when the IR spectrum of the obtained polymer was measured, it was found to be 1780ew-'1160cm-'75
An absorption peak peculiar to aromatic polycarbonate was observed at 0ewi-'690cm-'.

Also, at 260℃ 1.27(!11X6.35ew+X
O.

A square plate of 32 (up to) t was press-molded and its notched Izo impact strength was measured according to ASTM D-256, and it was found to be 72 kg-cm/cm, which is the same value as that of a polymer polymerized by the phosgene method.

Comparative Example 1 The same operations as in Example 1 were performed except that phenylacetate was not used in Example 1.

The obtained polymer had a ηlnh of 0.13, and a high polymer that could be used as a molding material was not obtained.

From this, it is clear that the manufacturing method of the present invention is superior.

Example 2 The same operation as in Example 1 was carried out, except that 0.043 g of motuputyl monohydroxytin oxide was used instead of tetrabutyl titanate as a catalyst.

The resulting polymer is a thin electrically conductive polymer with ηInh
was 0.52.

In addition, when the notched isot impact strength of this polymer was measured in the same manner as in Example 1, it was found to be 60 kg-cm/cm.
showed an excellent value.

Comparative Example 2 The same operation as in Example 1 was performed except that 0.06 g of antimony dioxide was used instead of tetrabutyl titanate as a catalyst.

The obtained reaction product was a viscous liquid, and the polymerization reaction did not proceed at all.

From this, it is clear that the catalyst of the present invention has high catalytic activity.

Example 3 The same operation as in Example 1 was performed except that 50.3 g of diethyl carbonate was used as the dialkyl carbonate.

The resulting polymer had a ηlnh of 0.56 and a notched eyelet impact strength of 73 kg-cm/cm.

Comparative Example 3 The same operations as in Example 2 were performed except that 88.0 g of phenol was used instead of the phenylacetate used in Example 2.

The resulting polymer had a ηlnh of 0.39 and a notched Izot impact strength of 28 kg-cm/cm.

From this, the effect of improving polymerizability by the phenylacetate of the present invention is clear.

<Effects of the Invention> When aromatic polycarbonate is produced according to the present invention, aromatic polycarbonate can be produced economically with relatively simple operations and equipment without using highly toxic phosgene gas.

Claims (1)

[Claims] In the presence of a transesterification catalyst selected from the group of organotitanium(IV) compounds and organotin(IV) compounds,
O-OR...(I) (In the formula, R represents an alkyl group having 1 to 3 carbon atoms.) A dialkyl carbonate represented by O-OR...(I) is reacted with bisphenol-A-bisacetate and phenyl acetate. A method for producing aromatic polycarbonate.