JPH0649753B2 - Method for producing polycarbonate by melting method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polycarbonate by a transesterification method. More specifically, in a method for producing a polycarbonate by a melt reaction of a bishydroxy compound and a carbonic acid ester, a transesterification reaction is carried out in the presence of a phenol solution of the following formula (I) as a catalyst, and after the reaction, the following formula ( The present invention relates to a method in which a phosphorus compound represented by II) is added and a polycondensation reaction is subsequently performed to easily obtain a tough polycarbonate having excellent thermal stability.

^{_{(R 1 4 NBH 4 (I}} ) ( wherein R ¹ is independently an alkyl group having 1 to 4 carbon atoms, an aryl group, or an aralkyl group having 6 to 10 carbon atoms of 6 to 10 carbon atoms.) (In the formula, R ² represents an alkyl, aralkyl, aryl or alkaryl group having 1 to 25 carbon atoms.) [Prior Art and Problems] Conventionally, phosphorus compounds have been used to obtain a polycarbonate having improved heat resistance. The method of copolymerizing is well known (US Pat. No. 4,054,552).

However, these are mostly related to the polycarbonate obtained by employing the phosgene method, which is subject to toxicity problems and production restrictions, and not to the transesterification method as in the present invention.

[Means for solving problems]

As a result of earnest studies on improvement of heat resistance stability, the present inventors have arrived at a method of producing a polycarbonate having heat resistance stability and excellent toughness by a transesterification reaction very easily.

That is, the present invention is a method for producing a polycarbonate by a melt reaction of a bishydroxy compound and a carbonate ester,
As a catalyst, a compound represented by the following formula (I) is allowed to exist in a phenol solution at a concentration of 10 ^-1 to 10 ^-4 mol% with ^respect to a bishydroxy compound, and an ester conversion reaction is carried out. The present invention relates to a method for producing a polycarbonate by the melting method, which comprises adding a phosphorus compound represented by the formula (4) and then conducting a polycondensation reaction.

(R ¹ ) ₄ NBH ₄ (I) (In the formula, R ¹ independently represents an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 6 to 10 carbon atoms.) (In the formula, R ² represents an alkyl, aralkyl, aryl or alkaryl group having a carbon number of 1 to 25.) Examples of the bishydroxy compound used in the present invention include bisphenol type compounds represented by the following formula. , Used individually or as a mixture.

(Where X is _{- (CH 2) n -,} -CO -, - O -, - S -, - SO
-, - represents a divalent group represented by - SO _2. R ³ and R ⁴ represent hydrogen, methyl group, ethyl group, n-propyl group, 1-propyl group, n-butyl group, 1-butyl group and phenyl group, and R ³ and R ⁴ may be the same kind. Also, they may be of different types. The above m is a positive integer of 4 to 7, and n is a positive integer of 1 to 3. ) Specific examples of the bisphenol type compound include 4,4′-dihydroxydiphenylmethane and 4,4 ′.
-Dihydroxydiphenyl-1,2-ethane, 4,4 '
-Dihydroxy diphenyl-1,1-ethane, 4,
4'-dihydroxydiphenyl-1,1-butane,
4,4'-dihydroxydiphenyl-1,1-isobutane, 4,4'-dihydroxydiphenyl-2,2-
Propane, 4,4'-dihydroxydiphenyl-2,
2'-butane, 4,4'-dihydroxy diphenyl-
2,2-Pentane, 4,4'-dihydroxydiphenyl-2,2- (4-methylpentane), 4,4'-dihydroxydiphenyl-diphenylmethane, 4,4'-
Dihydroxy diphenylphenylmethyl methane,
4,4'-dihydroxydiphenyl-1,1-cyclopentane, 4,4'-dihydroxydiphenyl-1,
1-cyclohexane, 4,4'-dihydroxy diphenyl ether, 4,4'-dihydroxy diphenyl ketone, 4,4'-dihydroxy diphenyl sulfide, 4,4'-dihydroxy diphenyl sulfoxide, 4, 4'-dihydroxy diphenyl sulfone and the like can be mentioned. Furthermore, these divalent phenols are the main components, and some of them are dihydroxybenzene, dihydroxynaphthalene, dihydroxybiphenyl, or aromatic compounds containing two phenolic hydroxyl groups including their substituent derivatives. It may be replaced.

The carbonic acid diester used in the present invention includes diphenyl carbonate, bis (p-chlorophenyl) carbonate, bis (p-nitrophenyl) carbonate, bis (o-nitrophenyl) carbonate, bis (o-chlorophenyl). ) Carbonates, diallyl carbonates with unsubstituted and nuclear substituents such as ditolyl carbonate.

The polymerization catalyst used in the present invention is represented by the following formula (I), wherein R ¹ is an alkyl group having 1 to 4 carbon atoms (for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl). Group) or an aryl or aralkyl group having 6 to 10 carbon atoms (eg phenyl, benzyl group). Particularly preferred is when all R ¹ are the same and are methyl.

(R ¹ ) ₄ NBH ₄ (I) (wherein R ¹ independently represents an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 6 to 10 carbon atoms). The compound of formula (I) used as a catalyst is added to the system as a phenol solution. The preferred concentration is 0.06 to 60 mg / cc phenolic compound. The addition amount of the catalyst compound is 10 ^-1 to 10 ^-4 mol% with respect to the bishydroxy compound.

The phosphorus compound used in the present invention is represented by the following formula (II), wherein R ² is an alkyl, aralkyl, aryl or alkaryl group having 1 to 25 carbon atoms (eg methyl,
Ethyl, propyl, butyl, phenyl, benzyl and tolyl groups). Particularly preferred is an ethyl group. The preferred amount used is 10 to 5000 pp in the reaction system.
This is the amount that gives the concentration of m. More preferable range is 100 to
It is 1000 ppm.

(In the formula, R ² represents an alkyl, aralkyl, aryl or alkaryl group having 1 to 25 carbon atoms.) Further, when this phosphorus compound is allowed to coexist from the initial stage of the reaction and reacted, a tough polymer is obtained. However, it must be added after the completion of the transesterification reaction. The transesterification reaction referred to here is a step of producing a monovalent phenol from a divalent phenol and a carbonic acid diester to give an initial condensate, which is about 95% of the theoretical amount of the produced monovalent phenol. It means the period until% is distilled.

The transesterification reaction is initiated by allowing a catalytic amount of a phenol solution of the compound represented by the formula (I) as a transesterification catalyst to be present in a bishydroxy compound or a carbonic acid ester, and heating at 150 to 180 ° C. in a nitrogen atmosphere.

As the reaction proceeds, an aromatic or aliphatic monooxy compound is produced, so the temperature is gradually raised to 200 to 22.
The temperature is raised to 0 ° C., and at the same time, the pressure of the reaction system is also reduced from 760 mmHg to 100 to 20 mmHg, and the produced monooxy compound is distilled off from the system. Distillation of monooxy compounds, which is close to the theoretical amount, is completed in about 2 hours. At this point, a predetermined amount of the phosphorus compound is added, and then the temperature is raised to further increase the degree of vacuum in the system to proceed the polycondensation reaction, and finally to 270
To 290 ℃, pressure less than a few mmHg, preferably 1mm
The polycondensation reaction is completed by maintaining the content at Hg or less, and a high molecular weight polymer can be obtained.

The theoretical ratio of carbonic acid ester to bishydroxy compound in the reaction should be such that a high molecular weight polymer can be obtained in an equimolar amount. It is preferable to use a slightly excess amount of the carbonic acid ester in excess of the theoretical amount in order to cause the bishydroxy compound, which is liable to occur, to rapidly undergo the initial condensation reaction with the carbonic acid ester to obtain an intermediate which is relatively stable against thermal decomposition and to proceed the reaction.

The obtained polymer is a known antioxidant, ultraviolet absorber, kaolin, silica, mica, talc, titanium dioxide, alumina, glass fiber, carbon fiber or the like filler or reinforcing material according to the purpose, dyeing for coloring. Extrusion molding as a film or sheet, using release agents such as pigments, ester waxes, hydrocarbon waxes, amide waxes, and flame retardants such as octabromodiphenyl and tetrabromobisphenol polycarbonates. Or for injection molding.

The produced polymer obtained by the production method of the present invention does not require a purification step such as washing and can be put into a molding machine as it is to be a molded product, and has heat stability higher than that of a polymer obtained by a conventional melting method. It is expected that it will exhibit excellent performance for various applications such as housings, automobile parts, home electric appliance parts, etc., since it has excellent toughness and further has toughness without lowering the molecular weight.

〔Example〕

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In Examples and Comparative Examples, all units are by weight unless otherwise specified.

Example 1 228 g of bisphenol A, diphenyl carbonate 2
19 g (molar ratio 1.025) was charged into a 1-volume reactor equipped with a stirrer, and after purging with nitrogen, it was melted at 150 to 160 ° C. Next, as a catalyst, 1 ml of a 0.1 mol / concentration phenol solution of (CH ₃ ) ₄ NBH ₄ was added (10 ^-2 mol% relative to bisphenol A), and the temperature was gradually raised to 220 ° C in about 3 hours. did. At the same time pressure from 100mmHg to 2
It was lowered to 0 mmHg and about 180 ml of phenol was distilled off. After the addition of 0.1 ml of diethyl phenylphosphonate, the temperature was raised and the pressure was reduced to 270 ° C. and 0.5 mmHg for about 2 hours. The reaction was continued for another hour under these conditions to obtain a polycarbonate. This polycarbonate was almost colorless and transparent, and the intrinsic viscosity [η] of the methylene chloride solution at 20 ° C was 0.555.

Further, the thermal decomposition behavior was measured with a differential thermogravimetric analyzer (manufactured by Rigaku Denki Co., Ltd.) as an evaluation of heat resistance. The temperature at which the weight loss reached 3% (T ₃ ) was 445 ° C, and the temperature at which the weight loss reached 5% (T ₅ ) was 467 ° C.

These results are summarized in Table 1 together with other examples and comparative examples.

Example 2 In Example 1, dimethyl phenylphosphonate was used in place of diethyl phenylphosphonate as the phosphorus compound,
The same operation was performed.

The hue, intrinsic viscosity and thermal decomposition behavior of the obtained polymer were measured by thermogravimetric analysis and are shown in Table 1.

Example 3 The same operation as in Example 1 was carried out by using diphenyl phenylphosphonate instead of diethyl phenylphosphonate as the phosphorus compound.

The hue, intrinsic viscosity and thermal decomposition behavior of the obtained polymer were measured by thermogravimetric analysis and are shown in Table 1.

Comparative Example 1 20 methylene chloride solution of a polymer obtained by polymerizing phenylphosphonic acid in place of diethyl phenylphosphonate as a phosphorus compound in Example 1
The intrinsic viscosity [η] at 0 ° C was 0.350. Other physical properties are shown in Table 1.

Comparative Example 2 The intrinsic viscosity [η] at 20 ° C. of a methylene chloride solution of a polymer obtained by performing the same operation as in Example 1 except that diethyl phenylphosphonate was added at the same time as the raw material monomer was 0. It was .375. Other physical properties are shown in Table 1.

Claims (1)

[Claims] 1. A method for producing a polycarbonate by a melt reaction of a bishydroxy compound and a carbonic acid ester,
A compound represented by the following formula (I) as a catalyst is allowed to exist as a phenol solution in a concentration of 10 ^-1 to 10 ^-4 mol% with ^respect to a bishydroxy compound, and an ester conversion reaction is carried out. A method for producing a polycarbonate by the melting method, which comprises adding the phosphorus compound represented by II) and then conducting a polycondensation reaction. (R ¹ ) ₄ NBH ₄ (I) (In the formula, R ¹ independently represents an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 6 to 10 carbon atoms.) (In the formula, R ² represents an alkyl, aralkyl, aryl or alkaryl group having 1 to 25 carbon atoms.)