JP2001302780A - Branched aromatic polycarbonate and its manufacturing method - Google Patents

Abstract

(57) [Problem] To provide a branched aromatic polycarbonate having improved fluidity under a high load, and further improved hue and retention heat stability, and a method for producing the same. A raw material is provided in the presence of a transesterification catalyst.
In producing an aromatic polycarbonate by reacting a carbonic acid diester with an aromatic dihydroxy compound, as a branching agent, one or more carboxyl groups, carboxylic acid ester groups or halocarbonyl groups in one molecule, and two or more hydroxyl groups The compound having a group is polymerized using not less than 0.01 mol% with respect to the aromatic dihydroxy compound as a raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a branched aromatic polycarbonate having excellent quality and a method for producing the same.
More particularly, the present invention relates to a branched aromatic polycarbonate having improved fluidity under high load, and improved hue and retention stability, and a method for producing the same.

[0002]

2. Description of the Related Art Aromatic polycarbonates are excellent in mechanical properties such as impact resistance, heat resistance, transparency and the like, and are used in various fields in various applications. By the way, generally used aromatic polycarbonates have a linear molecular structure, and polycarbonates having such a molecular structure may be inferior in melt elasticity, melt strength, etc. during melt molding. , Melt elasticity,
Improvement in molding characteristics such as melt strength is desired. As a method for improving the molding properties such as melt elasticity and melt strength of such a polycarbonate, conventionally, by an interfacial polymerization method,
1,1,1- as a branching agent together with bisphenol A
Tris (4-hydroxyphenyl) ethane (THP
E), 1,3,5-tris (4-hydroxyphenyl)
A method of branching a polycarbonate using a polyfunctional compound such as benzene is known (Japanese Patent Publication No. 44-197).
17149, JP-B-47-2918, JP-A-2-55725, JP-A-4-89824, etc.).

However, aromatic polycarbonates are:
Even in the case of a linear structure, a polycarbonate having a high melt viscosity and a branched structure introduced by copolymerization of a polyfunctional compound has a higher melt viscosity and lowers fluidity. As described above, polycarbonates having a high melt viscosity and poor fluidity are difficult to obtain a uniform molded product stably due to limited molding conditions and uneven molding.

In order to solve these problems, various attempts have been made in a melt polymerization method using a carbonic acid diester and an aromatic dihydroxy compound, but the fluidity under a high load has been reduced. In addition, the branching agent is decomposed at a high temperature to cause no effect of branching, further cause coloring, and a satisfactory product cannot be obtained.
JP-A-89824, JP-A-6-136112,
JP-B-7-37517, JP-B-7-116285
Reference).

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problems associated with the prior art as described above, in which the fluidity under high load is improved, and the hue and retention stability are improved. It is another object of the present invention to provide a branched aromatic polycarbonate having improved properties and a method for producing the same.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to find a branched aromatic polycarbonate having excellent hue and excellent melting characteristics such as melt strength.
By using a specific amount of a specific branching agent and producing a branched aromatic polycarbonate, it has been found that fluidity under a high load is improved, and that a hue and retention heat stability are further improved. The present invention has been completed.

That is, the present invention provides a method for producing an aromatic polycarbonate by reacting a carbonic acid diester with an aromatic dihydroxy compound as a raw material in the presence of a transesterification catalyst. A carboxyl group, a carboxylic acid ester group or a halocarbonyl group, and a compound having two or more hydroxyl groups, relative to the starting aromatic dihydroxy compound,
A method for producing a branched aromatic polycarbonate, characterized in that it is polymerized using at least 0.01 mol%. In addition, the present invention is obtained by reacting a carbonic acid diester with an aromatic dihydroxy compound in the presence of a transesterification catalyst, the degree of branching MIR is 15 or more, the hue YI is 3.5 or less,
Retention heat stability YI is 10 or less and MI under high load is 15
The present invention relates to a branched aromatic polycarbonate characterized by the above.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically. The branched aromatic polycarbonate of the present invention uses, as raw materials, a carbonic acid diester and an aromatic dihydroxy compound, and as a branching agent, one or more carboxyl groups, carboxylic acid ester groups or halocarbonyl groups in one molecule, and It can be obtained by subjecting a compound having two or more hydroxyl groups to melt polycondensation in the presence of a transesterification catalyst.

The carbonic diester used in the present invention is generally represented by the following general formula (3). Equation (3) (Wherein G and G ′ are an aliphatic group having 1 to 18 carbon atoms or a substituted aliphatic group, or an aromatic group or a substituted aromatic group, and G and G ′ may be the same or different. .)

The diester carbonate represented by the general formula (3) includes, for example, dialkyl carbonate compounds such as dimethyl carbonate, diethyl carbonate and di-t-butyl carbonate, and substituted diphenyl carbonates such as diphenyl carbonate and ditolyl carbonate. Is exemplified. Preferred are diphenyl carbonate and substituted diphenyl carbonate, and particularly preferred is diphenyl carbonate. These carbonic diesters can be used alone or
A mixture of more than one species may be used.

The aromatic dihydroxy compound used in the present invention is represented by the following formula (4). Equation (4)

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Wherein W is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms,
A cycloalkylene group having 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, or -O-, -S-, -CO-, -SO
—, —SO ₂ — selected from the group consisting of divalent groups, wherein Y and Z are a halogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and p and q are 0 to 2 And Y and Z, and p and q may be the same or different. )

Examples of the aromatic dihydroxy compound represented by the above formula (4) include bis (4-hydroxydiphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, and 2,2-bis (4 -Hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3-t-butylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2, Bisphenols such as 2-bis (4-hydroxy-3,5-dibromophenyl) propane, 4,4-bis (4-hydroxyphenyl) heptane and 1,1-bis (4-hydroxyphenyl) cyclohexane; 4,4 ′ −
Biphenols such as dihydroxybiphenyl and 3,3 ', 5,5'-tetramethyl-4,4'-dihydroxybiphenyl; bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfide, bis (4-
Hydroxyphenyl) ether, bis (4-hydroxyphenyl) ketone and the like. Particularly preferably,
2,2-bis (4-hydroxyphenyl) propane (hereinafter abbreviated as bisphenol A) may be mentioned. These aromatic dihydroxy compounds are used alone or as a mixture of two or more.

In producing the aromatic polycarbonate in the present invention, the carbonic acid diester is used in excess with respect to the aromatic dihydroxy compound. That is, it is used in a molar ratio of 1.01 to 1.30, preferably 1.02 to 1.20, based on the aromatic dihydroxy compound. Under the same reaction conditions, as this molar ratio decreases, the reaction rate increases, and the viscosity average molecular weight of the polycarbonate increases.
In addition, when the molar ratio is increased in this range, the reaction rate decreases, and the viscosity average molecular weight decreases. The molar ratio is 1.01
The terminal OH of the polycarbonate obtained when it becomes smaller
Although the amount of the group is increased and the reactivity is increased, the thermal stability, hydrolysis resistance and the like are deteriorated, and are not suitable for ordinary use. If it exceeds 1.30, it becomes difficult to produce an aromatic polycarbonate having a desired molecular weight.

In the present invention, a specific amount of a compound having one or more carboxyl groups, carboxylic acid ester groups or halocarbonyl groups, and two or more hydroxyl groups in one molecule is used. As such compounds, for example, compounds represented by general formulas (1) and (2) can be used.

Equation (1)

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(Wherein at least one of ring A and ring B is
It has a carboxyl group, a carboxylic ester group or a halocarbonyl group. At this time, the ester group is an aliphatic or aromatic group which may be substituted with a halogen atom. X is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, or -O-, -S -, - CO -, - SO -, - SO 2 -
Is selected from the group consisting of divalent groups represented by )

Equation (2)

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(Wherein at least one of ring C, ring D, ring E and ring F has a carboxyl group, a carboxylic ester group or a halocarbonyl group. In this case, the ester group is substituted with a halogen atom. X is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, or an alkyl group having 5 to 15 carbon atoms.
, A cycloalkylidene group having 5 to 15 carbon atoms, or -O-, -S-, -CO-, -SO-,
Selected from the group consisting of divalent groups represented by - -SO _2. )

As such a compound, specifically,
Examples include compounds of the following formula:

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[0021]

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[0022]

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[0023]

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[0024]

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Of these, formulas (5) to (14) are particularly preferably used. Such a polyfunctional compound is used in an amount of 0.01 mol% based on the aromatic dihydroxy compound as a raw material.
As described above, it is usually 1 mol% or less, preferably 0.05 to 0.1 mol%.
8 mol%, particularly preferably 0.1 to 0.6 mol%, is added and used. These may be used alone or in combination of two or more. When the above compound is used, the fluidity under a high load is extremely good, and the hue and the retention heat stability are excellent, as compared with a branched polymer having the same degree of branching. This is probably because the compound functions as a branching agent, and the carboxyl group, carboxylic acid ester group and / or halocarbonyl group in the compound forms an ester bond by polymerization.

When an aromatic polycarbonate is produced by the transesterification method, a transesterification catalyst is usually used. As the transesterification catalyst used in the present invention, an alkali metal compound and / or an alkaline earth metal compound are mainly used, and a basic boron compound,
It is also possible to use a basic compound such as a basic phosphorus compound, a basic ammonium compound or an amine compound in combination. These catalysts may be used alone,
Two or more kinds may be used in combination.

The amount of the catalyst used is in the range of 1 × 10 ^-9 to 1 × 10 ^-3 mol per mol of the aromatic dihydroxy compound. Particularly, the alkali metal compound having good physical properties and good handling is used. and / or 1 × 10 over ^8-1 per mole of the aromatic dihydroxy compound with an alkaline earth compound
× 10 ^-5 mol, and preferably in the range of 2 × 10 over ⁸ to 8 × 10 ^-6 mol. If the amount is less than this, the polymerization activity required for producing a polycarbonate having a predetermined molecular weight and a terminal hydroxyl group cannot be obtained. If the amount is more than this, the polymer hue deteriorates and the number of branches increases.

Examples of the alkali metal compound include sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, cesium hydrogen carbonate, sodium carbonate, potassium carbonate, and carbonate. Lithium, cesium carbonate, sodium acetate, potassium acetate, lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium borohydride, potassium borohydride, lithium borohydride, hydrogenated Cesium boron, sodium borohydride, potassium borohydride, lithium borohydride, cesium borohydride, sodium benzoate, potassium benzoate, lithium benzoate,
Cesium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, dicesium hydrogen phosphate, disodium phenylphosphate, dipotassium phenylphosphate, dipotassium phenylphosphate, dilithium phenylphosphate, phenylphosphate 2 Cesium, sodium, potassium, lithium, cesium alcoholate, phenolate, bisphenol A
Disodium salt, dipotassium salt, dilithium salt, dicesium salt and the like.

Further, as the alkaline earth metal compound,
For example, calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium bicarbonate, barium bicarbonate, magnesium bicarbonate, strontium bicarbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, acetic acid Examples include barium, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate and the like.

Specific examples of the basic boron compound include tetramethyl boron, tetraethyl boron, tetrapropyl boron, tetrabutyl boron, trimethylethyl boron, trimethylbenzyl boron, trimethylphenyl boron, triethylmethyl boron, triethylbenzyl boron, triethylphenyl Hydroxides such as boron, tributylbenzylboron, tributylphenylboron, tetraphenylboron, benzyltriphenylboron, methyltriphenylboron, butyltriphenylboron and the like can be mentioned.

Examples of the basic phosphorus compound include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphine, and the like.
Alternatively, quaternary phosphonium salts and the like can be mentioned.

Examples of the basic ammonium compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide,
Trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltrimoxide Examples include phenylammonium hydroxide, methyltriphenylammonium hydroxide, and butyltriphenylammonium hydroxide.

Examples of the amine compound include 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine,
2-hydroxypyridine, 2-methoxypyridine, 4-
Methoxypyridine, 2-dimethylaminoimidazole,
Examples include 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline and the like.

The transesterification is generally carried out in two or more stages. Specifically, the first-stage reaction is performed under a reduced pressure of 9.3 × 10 ^{4 to} 1.33 × 10 ³ Pa.
The reaction is carried out at a temperature of 20 to 260 ° C, preferably 180 to 240 ° C for 0.1 to 5 hours, preferably 0.1 to 3 hours. Next, the reaction temperature was increased while increasing the degree of pressure reduction of the reaction system, and finally 240 to 32 under a reduced pressure of 133 Pa or less.
The polycondensation reaction is carried out at a temperature of 0 ° C. The type of reaction may be any of a batch type, a continuous type or a combination of a batch type and a continuous type, and the apparatus used may be any of a tank type, a tube type and a column type.

In the aromatic polycarbonate produced by the above method, low molecular weight compounds such as a raw material monomer, a catalyst and an aromatic hydroxy compound and an aromatic polycarbonate oligomer which are by-produced in a transesterification reaction remain. Among them, the raw material monomer and the aromatic hydroxy compound have a large residual amount, and adversely affect physical properties such as heat aging resistance and hydrolysis resistance. In the present invention, it is preferable to remove them, and specific examples include continuous devolatilization with a vent-type extruder. At this time, the basic transesterification catalyst remaining in the resin is neutralized with an acidic compound in advance and deactivated, thereby suppressing side reactions during devolatilization and efficiently removing the raw material monomer and the aromatic hydroxy compound. can do.

In the present invention, the acidic compound or its precursor to be added is not particularly limited, and any compound can be used as long as it has an effect of neutralizing the basic transesterification catalyst used in the polycondensation reaction. Specifically, hydrochloric acid, nitric acid, boric acid, sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, hypophosphorous acid,
Polyphosphoric acid, adipic acid, ascorbic acid, aspartic acid, azelaic acid, adenosine phosphate, benzoic acid, formic acid, valeric acid, citric acid, glycolic acid, glutamic acid,
Glutaric acid, cinnamic acid, succinic acid, acetic acid, tartaric acid, oxalic acid, p-toluenesulfinic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, nicotinic acid, picric acid, picolinic acid, phthalic acid, terephthalic acid, propionic acid Benzenesulfinic acid, benzenesulfonic acid, malonic acid, maleic acid and the like, and Bronsted acids and esters thereof. These may be used alone or in combination of two or more. Among these acidic compounds or precursors thereof, a sulfonic acid compound or an ester compound thereof, for example, p-toluenesulfonic acid, methyl p-toluenesulfonate, butyl p-toluenesulfonate and the like are particularly preferable.

The amount of the acidic compound or the precursor thereof is 0.1 to 50 times, preferably 0.5 to 50 times the neutralization amount of the basic transesterification catalyst used in the polycondensation reaction.
It is added in a range of up to 30 times mol. As the timing of adding the acidic compound or its precursor, if it is after the polycondensation reaction,
There are no particular restrictions on the method of addition, depending on the properties of the acidic compound or its precursor and desired conditions, a method of direct addition, a method of dissolving in an appropriate solvent, and a method of adding pellets or flakes. Any method such as a method using a master batch may be used.

The twin screw extruder used in the present invention includes:
In the intermeshing type twin screw extruder, the rotation direction may be the same direction rotation or different direction rotation. In particular, those having a vent portion after the acidic compound addition portion are preferable. Although the number of vents is not limited, a multistage vent of 2 to 10 stages is usually used.
In the extruder, if necessary, additives such as a stabilizer, an ultraviolet absorber, a release agent, and a coloring agent may be added and kneaded with the resin.

According to the present invention, the degree of branching MIR is 15 or more, preferably 15 to 30,
Branching having a hue YI of 3.5 or less, preferably 1.5 to 3.5, a retention heat stability YI of 10 or less, preferably 4 to 10, and a high load MI of 15 or more, preferably 15 to 50. Aromatic polycarbonate can be easily produced. The branched aromatic polycarbonate produced by the present invention is processed and injection-molded by extrusion, and particularly, blow-molded hollow parts and large-sized parts requiring materials having high melt strength and excellent shape retention characteristics of extruded products. Suitable for panel applications.

[0040]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples unless it exceeds the gist. The percentages and parts in the examples are% by weight or parts by weight unless otherwise specified. The physical properties of the polycarbonates obtained in the examples and comparative examples were measured as follows.

(1) Viscosity average molecular weight (Mv): 6 g / l
Was measured for intrinsic viscosity using a Ubbelohde viscometer, and the viscosity average molecular weight was determined by the following equation.

[0042]

[Η] = 1.23 × 10 ⁻⁴ (Mv) ^0.83

(2) Hue (YI): Tristimulus value XYZ, which is an absolute value of color, of a 3 mm-thick press sheet was measured with a color tester (SC-1-CH manufactured by Suga Test Instruments Co., Ltd.).
Was measured, and the YI value as an index of yellowness was calculated by the following relational expression. YI = (100 / Y) × (1.28 × X−1.06 ×
Z) The larger the YI value, the more colored.

(3) Degree of branching (MIR): The weight (g) of a sample extruded for 10 minutes under a load of 21.6 kg and 2.16 kg at 260 ° C. is measured and expressed as a ratio between the two. The larger the value, the greater the degree of branching.

(4) Retention heat stability test (heat-resistant hue YI) A color tester (SC-1 manufactured by Suga Test Instruments Co., Ltd.) was manufactured at 360 ° C. for 10 minutes with the fifth shot.
CH) by the transmission method.

Example 1 Under a nitrogen gas atmosphere, diphenyl carbonate, bisphenol A and a branching agent were used.
Compound A (see formula 6) shown in Table 1 was used for each of the compounds (205.0).
Mol / h, 197.1 mol / h and 0.59 mol (0.3 mol% based on 1 mol of bisphenol A) were continuously fed to a raw material mixing tank prepared at 140 ° C. under a nitrogen atmosphere. The solution was sent. The prepared raw material mixture is continuously supplied through a raw material introduction pipe into a first vertical stirring polymerization tank having a volume of 100 L controlled at 220 ° C. and 1.33 × 10 ⁴ Pa, and the average residence time becomes 60 minutes. Thus, the liquid level was kept constant while controlling the opening of the valve provided in the polymer discharge line at the bottom of the tank. Simultaneously with the start of the supply of the above mixture, a 2% by weight aqueous cesium carbonate solution was continuously supplied as a catalyst at a flow rate of 3.2 ml / hour (1 × 10 ⁻⁶ mol per mol of bisphenol A).

The polymerization liquid discharged from the bottom of the tank is continuously
The second and third vertical polymerization tanks having a capacity of 100 L and the horizontal polymerization tank having a fourth capacity of 150 L are sequentially and continuously supplied,
It was withdrawn from the polymer outlet at the bottom of the fourth polymerization tank. Next, in a molten state, this polymer is fed into a twin-screw extruder, and kneaded continuously with butyl p-toluenesulfonate (10 times the molar amount of cesium carbonate used as a catalyst). Into a strand, and cut with a cutter to obtain a pellet. The reaction conditions in the second to fourth polymerization tanks are respectively set in the second polymerization tank (240 ° C., 2.00 × 10 ^3).
Pa, 75 rpm), third polymerization tank (270 ° C., 66.7)
Pa, 75 rpm), fourth polymerization tank (280 ° C., 66.7)
(Pa, 10 rpm), conditions were set to high temperature, high vacuum, and low stirring speed as the reaction progressed. During the reaction, the liquid level was controlled so that the average residence time in the second to fourth polymerization tanks was 60 minutes, and at the same time, phenol by-produced was distilled off. A polycarbonate having a viscosity average molecular weight of 24100 was obtained, and this was injection molded into a test piece having a thickness of 3 mm, and the hue (YI) was measured. Furthermore, the measurement of the degree of branching (MIR) at 260 ° C. and the retention heat stability test (heat-resistant hue YI) were performed. Table 1 shows the results.

Examples 2-3 A polymer was produced in the same manner as in Example 1 except that the branching agents (compounds B and C) shown in Table 1 were used. Table 1 shows the results.

Comparative Example 1 In Example 1, 1,1,1-tris (4-hydroxyphenyl) was used as a branching agent.
A polymer was produced in the same manner as in Example 1 except that ethane (THPE) was used. Table 1 shows the results.

Comparative Example 2 A polymer was produced in the same manner as in Example 1 except that 1,3,5-tris (4-hydroxyphenyl) benzene (THPB) was used as a branching agent. . Table 1 shows the results.

Comparative Example 3 A polymer was produced in the same manner as in Example 1 except that no branching agent was used. Table 1 shows the results.

Table 1 shows that the aromatic polycarbonate obtained by the method of the present invention has improved fluidity and moldability by using a branching agent. Further, the degree of branching (MIR) is comparable to that of an aromatic polycarbonate obtained by a method using a conventional branching agent, but the hue YI,
It can be seen that the retention heat stability (heat resistance hue YI) and the MI under high load are remarkably excellent.

[0053]

[Table 1]

* 1: Compound A = compound of formula (6)

Embedded image * 2: Compound B = compound of formula (10)

Embedded image * 3: Compound C = compound of formula (12)

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According to the present invention, a branched aromatic polycarbonate having improved fluidity under high load, and improved hue and retention heat stability can be produced. Therefore, it is suitable for extrusion processing and injection molding, particularly for use in hollow parts and large panels by blow molding, which require a material having high melt strength and excellent shape retention characteristics of extrudates.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J029 AA09 AB01 AB04 AC01 AC02 AD10 AE01 BB10A BB10B BB12A BB13A BB13B BB18 BD09A BE05A BE07 BF14A BG06X BH02 DB07 DB13 HC03 HC04A HC05A HC05B

Claims (5)

[Claims] (1) As a raw material in the presence of a transesterification catalyst,
In producing an aromatic polycarbonate by reacting a carbonic acid diester with an aromatic dihydroxy compound, as a branching agent, one or more carboxyl groups, carboxylic acid ester groups and / or halocarbonyl groups, and two or more A method for producing a branched aromatic polycarbonate, comprising polymerizing a compound having a hydroxyl group of at least 0.01 mol% with respect to an aromatic dihydroxy compound as a raw material. 2. The method for producing a branched aromatic polycarbonate according to claim 1, wherein the branching agent is a compound represented by the formula (1). Formula (1) (In the formula, at least one of the ring A and the ring B has a carboxyl group, a carboxylic ester group or a halocarbonyl group, and the ester group is an aliphatic or aromatic group which may be substituted with a halogen atom. X is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, and a carbon atom having 5 to 5 carbon atoms.
15 cycloalkylidene groups or -O-, -S-,-
CO -, - SO -, - SO 2 - is selected from the group consisting of divalent groups represented by. ) 3. The method for producing a branched aromatic polycarbonate according to claim 1, wherein the branching agent is a compound represented by the formula (2). Formula (2) (Wherein at least one of C ring, D ring, E ring, and F ring is
It has a carboxyl group, a carboxylic ester group or a halocarbonyl group, and the ester group is an aliphatic or aromatic group which may be substituted with a halogen atom. X is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, or -O-,-.
S -, - CO -, - SO -, - SO 2 - is selected from the group consisting of divalent groups represented by the two X's may be the same or different. ) 4. In the above reaction, it is preferable to use a catalyst containing 1 × 10 ⁻⁸ to 1 × 10 ⁻⁵ mol of an alkali metal and / or an alkaline earth metal per 1 mol of an aromatic dihydroxy compound as a raw material. A method for producing a branched aromatic polycarbonate according to any one of claims 1 to 3. 5. A compound obtained by reacting a carbonic acid diester with an aromatic dihydroxy compound in the presence of a transesterification catalyst,
A branched aromatic polycarbonate having a branching degree MIR of 15 or more, a hue YI of 3.5 or less, a retention heat stability YI of 10 or less, and a high load MI of 15 or more.