JP2000128976A - Production of polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polycarbonate having an excellent color hue by the fusion condensation polymerization using a carbonate diester as a raw material. SOLUTION: A method is provided, for producing a polycarbonate, which comprises the steps of (I) synthesizing a carbonate diester from a monohydroxy compound, a hydroxy compound of an alkali metal, and phosgene, (II) producing a polycarbonate using the carbonate diester by the fusion condensation polymerization, and (III) recovering the monohydroxy compound which is a by-product in step II to reuse it in step I, wherein the monohydroxy compound for the reuse contains anisole at 1-1000 ppm and trimethylamine at 1-100 ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polycarbonate produced by recycling a monohydroxy compound produced as a by-product when a polycarbonate is obtained by a melt condensation polymerization method.

[0002]

2. Description of the Related Art Aromatic dihydroxy compounds, especially so-called polycarbonate resins produced by interfacial polycondensation of bisphenol A and phosgene, are widely used in various applications due to their excellent mechanical and thermal properties. Since toxic phosgene is used, there is a problem in safety, and since methylene chloride is used as a solvent, there is an environmental problem. Therefore, recently, a method for producing a polycarbonate by transesterification without using methylene chloride or phosgene has been spotlighted.

[0003] However, since the polycarbonate resin produced by the transesterification method is produced at a high temperature for a long time, it is susceptible to impurities contained in the raw material, and compared with the polymer obtained by the interfacial polymerization method. There are many problems in producing a stable and good color tone polymer.

[0004] Diphenyl carbonate is preferably used as a raw material of polycarbonate by the melt condensation polymerization method. The method for producing diphenyl carbonate is a method using phosgene, or a method in which phenol and carbon monoxide are directly reacted in the presence of a catalyst. Various methods have been proposed, such as a method for carrying out the method, and phenol is used as a raw material. At that time, from the viewpoint of production cost, usually, after obtaining a polycarbonate by a melt polycondensation method, phenol produced as a by-product is recycled and used, but the phenol to be recycled is not contained in ordinary phenol. Contains impurities derived from additives such as catalysts and stabilizers added during polymerization.

[0005] Further, when diphenyl carbonate is synthesized using this, there is a concern that diphenyl carbonate containing impurities derived from phenol and impurities generated by deterioration may be obtained.

Therefore, when using carbonic acid diester as a raw material for polycarbonate, purification is performed by vacuum distillation, so-called hot water washing performed by contacting with hot water, or a combination thereof in order to remove impurities. . In order to remove impurities in carbonic acid diester to a high degree, it is considered possible to repeat purification many times or use large-scale equipment.However, it is disadvantageous in terms of cost and productivity, and even after purification, carbonic acid can be removed. Impurities are likely to remain in the diester, which may cause coloring of the polycarbonate using the raw material.

[0007]

As a result of intensive studies, (I) a dihydroxy carbonate was synthesized from a monohydroxy compound, a hydroxy compound of an alkali metal and phosgene,
(II) A polycarbonate is produced by a melt condensation polymerization method using the carbonic acid diester, and (III) a monohydroxy compound produced as a by-product in the above-mentioned step (II) is recovered.
In the method for producing a polycarbonate comprising reusing in the step of, it has been found that the monohydroxy compound to be reused contains a specific amount of anisole and / or trimethylamine, which is effective for producing a polycarbonate having an excellent hue. .

[0008]

That is, (I) a carbonate diester is synthesized from a monohydroxy compound, a hydroxy compound of an alkali metal and phosgene, and (II) a polycarbonate is produced by a melt condensation polymerization method using the carbonate diester. (III) In the method for producing a polycarbonate, comprising recovering a monohydroxy compound produced as a by-product in the step (II) and reusing the monohydroxy compound in the step (I), the monohydroxy compound to be reused is 1 ppm or more. 1
Not more than 000 ppm of anisole and / or 1 pp
The present invention relates to a method for producing a polycarbonate, comprising m to 100 ppm of trimethylamine.

That is, after a polycarbonate is obtained by a melt condensation polymerization method using a carbonic acid diester as a raw material, the by-produced monohydroxy compound is not contained in a normal monohydroxy compound, and is not contained in a catalyst or a catalyst added during polymerization. Includes impurities derived from additives such as agents. Examples of the impurities include organic compounds such as trimethylamine, anisole, orthocresol, paracresol, 2-methylbenzofuran, hydroxyacetone, and acetophenone, and various metal salts, but many of them have not been elucidated yet.

[0010] Among them, anisole contained in the circulating monohydroxy compound, which is a raw material of carbonic acid diester, is 1 p
It has been found that when the content is from pm to 1000 ppm or the content of trimethylamine is from 1 ppm to 100 ppm, it is effective for producing a polycarbonate having an excellent hue in a cycle of producing a polycarbonate by a melt condensation polymerization method using the same.

Further, the circulating monohydroxy compound contains 1 ppm to 1000 ppm of anisole and 1 ppm to 100 pp of trimethylamine.
m or less was found to be more preferable for the production of polycarbonate having excellent hue.

Although the mechanism is not clear, a specific amount of anisole and / or trimethylamine is contained in the monohydroxy compound which is a raw material of the carbonic acid diester, so that deterioration which is likely to occur in the circulating monohydroxy compound can be suppressed. It is assumed that the compound is stabilized and the generation of impurities that are difficult to purify and remove from the carbonic acid diester is suppressed, so that the hue of the obtained polycarbonate is improved.

On the other hand, anisole in the monohydroxy compound is 1000 ppm, or trimethylamine is 100 ppm.
If it exceeds pm, the hue of the polycarbonate obtained thereby decreases, which is not preferred. The mechanism is not clear, but for distilling carbonic acid diester, or
For the melt condensation polymerization of polycarbonate, 1000 ppm in the raw material monohydroxy compound when held in a molten state
The presence of more than anisole or more than 100 ppm of trimethylamine is presumed to produce impurities that cause the coloring of the polycarbonate. In addition, anisole 1 ppm or less in the raw material monohydroxy compound,
When the content of trimethylamine was 1 ppm or less, almost no effect was observed.

[0014] Anisole is 1 ppm or more and 1000 ppm
In order to obtain a monohydroxy compound containing 1 ppm or more and 100 ppm or less of trimethylamine, the monohydroxy compound produced as a by-product in the production of polycarbonate by melt condensation polymerization is recovered, and is not subjected to purification. Is also good.

As a method for purifying a monohydroxy compound produced as a by-product when producing polycarbonate by melt condensation polymerization, a commonly used method may be used, and a vacuum distillation method is preferred.

Specific examples of the monohydroxy compound include phenol, cresol, xylenol, chlorophenol, naphthyl alcohol, biphenyl alcohol and the like, and phenol is preferably used.

Specific examples of the carbonic acid diester include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl)
Carbonates.

As is conventionally known, an alkali metal salt of a monohydroxy compound is prepared from a monohydroxy compound and an alkali metal hydroxy compound in an organic solvent / water two-phase system, and further reacted with phosgene to form a diester carbonate. Can be manufactured.

When the carbonic acid diester is used as a raw material for polycarbonate, purification is carried out to remove impurities. As a purification method, there are vacuum distillation, so-called hot water washing performed by contact with hot water, or a combination thereof. For example, a method commonly used in the related art may be used.

The polycarbonate referred to in the present invention is produced by a transesterification reaction between an aromatic dihydroxy compound and a carbonic acid diester compound.

Here, the aromatic dihydroxy compound has the following formula (1)

[0022]

Embedded image

Is a compound represented by the formula:

In the above formula (1), Ra and Rb are the same or different and each represents a hydrogen atom, a halogen atom or a carbon atom of 1 to 1;
2 hydrocarbon groups. As the hydrocarbon group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms is preferable. Examples of the halogen atom include chlorine, bromine and iodine. m and n are the same or different and are 1 to 4.

Re is an alkylene group having 3 to 8 carbon atoms. Examples of the alkylene group include a pentylene group and a hexylene group.

In the formula, Rc and Rd are the same or different and are a halogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms. Examples of the hydrocarbon group include an aliphatic hydrocarbon group having 1 to 12 carbon atoms and an aromatic hydrocarbon group having 6 to 12 carbon atoms. As a halogen atom, chlorine,
Bromine, iodine and the like can be mentioned.

The aromatic dihydroxy compound includes:
Specific examples include the following compounds. That is, bis (hydroxy) such as 1,1-bis (4-hydroxy-t-butylphenyl) propane, 2,2-bis (4-hydroxyphenyl) propane, and 2,2-bis (4-hydroxybromophenyl) propane Aryl)
Alkanes, 1,1-bis (4-hydroxyphenyl)
Bis (hydroxyaryl) such as cyclopentane and 1,1-bis (4-hydroxyphenyl) cyclohexane
Dihydroxyaryl ethers such as cycloalkanes, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethylphenyl ether, 4,4'-dihydroxydiphenyl sulfide,
Dihydroxyaryl sulfides such as 4,4'-dihydroxy-3,3'-dimethylphenyl sulfide;
4,4'-dihydroxydiphenylsulfoxide, 4,
Dihydroxyarylsulfoxides such as 4'-dihydroxy-3,3'-dimethylphenylsulfoxide;
4,4'-dihydroxydiphenyl sulfone, 4,4 '
And dihydroxyarylsulfones such as -dihydroxy-3,3'-dimethylphenylsulfone.

Of these, in particular, 2,2-bis (4-
(Hydroxyphenyl) propane (bisphenol A) is preferably used. These aromatic dihydroxyl compounds can be used alone or in combination.

These aromatic dihydroxyl compounds can be used alone or in combination. Also, it is desirable to use the carbonate diester compound in an excess amount, preferably 1.01 to 1.20 mol, per 1 mol of the aromatic dihydroxy compound.

In the production of polycarbonate, the transesterification catalyst includes quaternary ammonium salts or quaternary phosphonium salts and / or alkali metal salts,
Alternatively, it is preferable to use a quaternary ammonium salt, a quaternary phosphonium salt and / or an alkaline earth metal salt for producing a polycarbonate having an excellent hue, which is the object of the present invention.

As these catalysts, alkali metal compounds and nitrogen-containing basic compounds are preferably used. Alkali metal compounds include alkali metal hydroxides, hydrocarbons, carbonates, acetates, nitrates, nitrites, sulfites, cyanates, thiocyanates, stearates, borohydrides, benzoates Acid salts, hydrogen phosphates, bisphenol salts, and phenol salts.

Specific examples include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, sodium carbonate,
Potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, sodium nitrate, potassium nitrate, lithium nitrate, sodium nitrite, potassium nitrite, lithium nitrite, sodium sulfite, potassium sulfite, lithium sulfite, sodium cyanate, potassium cyanate , Lithium cyanate, sodium thiocyanate,
Potassium thiocyanate, lithium thiocyanate, sodium stearate, potassium stearate, lithium stearate, sodium borohydride, lithium borohydride, potassium borohydride, sodium borohydride, sodium benzoate, potassium benzoate, benzoic acid Examples include lithium, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium salt, dipotassium salt, dilithium salt of bisphenol A, and sodium, potassium, and lithium salts of phenol.

In the present invention, if desired, the alkali metal compound of the catalyst is disclosed in Japanese Unexamined Patent Publication No.
An alkali metal salt of an ate complex of an element belonging to Group 14 of the periodic table or an alkali metal salt of an oxo acid of an element belonging to Group 14 of the periodic table described in JP-A-268091 can be used. Here, the elements of Group 14 of the periodic table refer to silicon, germanium, and tin. It is preferable to use these alkali metal compounds as a transesterification catalyst in order to achieve the object of the present invention.

The amount of the alkali metal compound used is 1 × 10 ^{−8 to} 5 × per mole of the aromatic dihydroxy compound.
It can be used in the range of 10 ^-6 mol. If the amount is out of the above range, the effect of suppressing the generation of foreign substances may be reduced, and the more preferable amount is 1 × 10 ⁻⁸ to 2 × 10 ⁻⁷ mol.

Examples of quaternary phosphonium salts include, for example, tetramethylphosphonium hydroxide (Me ₄ PO
H), benzyltrimethylphosphonium hydroxide (φ-CH ₂ (Me) ₃ POH), phosphonium hydroxides having an alkyl, aryl, alkylaryl group or the like such as hexadecyltrimethylphosphonium hydroxide, or tetramethylphosphonium borohydride (Me ₄ PBH ₄ ) and basic salts such as tetramethylphosphonium tetraphenylborate (Me ₄ PBPh ₄ ).

Examples of the nitrogen-containing basic compound include ammonium hydroxides having an alkyl, aryl, or araryl group such as tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide, and hexadecyltrimethylammonium hydroxide;
Examples include tertiary amines such as trimethylamine, dimethylbenzylamine and hexadecyldimethylamine, and basic salts such as tetramethylammonium borohydride and tetramethylammonium tetraphenylborate.

The nitrogen-containing basic compound is preferably used in such a ratio that the amount of ammonium nitrogen atoms in the nitrogen-containing basic compound is 1 × 10 −5 to 1 × 10 −3 equivalent per mole of the aromatic dihydroxy compound. A more preferable ratio is a ratio that is 2 × 10 ^{−5 to} 7 × 10 ⁻⁴ equivalents with respect to the same standard. A particularly desirable ratio is 5 × 10 ⁻⁵ to 5 with respect to the same standard.
× 10 ⁻⁴ equivalent.

In the manufacturing method disclosed in the present invention, for example, Japanese Patent Application Laid-Open No. H10-364 filed by the inventors
It is preferable to use a terminal blocking agent described in No. 97 to block the hydroxyl terminal of the polymer, and it is preferable to add a deactivator which deactivates the catalytic activity during or at the end of the polymerization.

As the catalyst deactivator, any known agent can be used, and preferably, a sulfonic acid compound such as an organic sulfonic acid salt, an organic sulfonic acid ester, an organic sulfonic acid anhydride, or an organic sulfonic acid betaine is preferable. .

As the catalyst deactivator, sulfonates are particularly preferred. Among them, JP-A-8-599 is particularly preferable.
The organic phosphonium salt or organic ammonium salt of sulfonic acid described in No. 75 is preferably used.

These catalyst deactivators are used in an amount of 0.01 to 500 ppm, preferably 0.01 to 30 ppm, based on the polymer.
0 ppm can be used.

In the production method disclosed in the present invention, a stabilizer such as a phosphite may be added within the scope of the present invention.

There are no particular restrictions on the specific methods such as the type, amount, timing and method of addition of these agents, and it is preferable to use those disclosed in the present invention for the material of the apparatus for performing these operations. .

The polymerization of polycarbonate (molten ester exchange reaction between a dihydroxy compound and a carbonic acid diester compound) can be carried out under the same conditions as those of a conventionally known ordinary method.

Specifically, the first-stage reaction is carried out at 80 to 25
At a temperature of 0 ° C., preferably 100 to 230 ° C., more preferably 120 to 190 ° C., for 0.5 to 5 hours, preferably 1 to 4 hours, more preferably 1.5 to 3 hours, under reduced pressure, the dihydroxy compound And a carbonic acid diester compound. Then, the reaction temperature is increased while increasing the degree of vacuum of the reaction system to carry out the reaction between the dihydroxy compound and the carbonic acid diester compound, and finally the dihydroxy compound is heated at 240 to 320 ° C. under a reduced pressure of 5 mmHg or less, preferably 1 mmHg or less. With a carbonic acid diester compound. The type of the apparatus for the polycondensation reaction is not particularly limited.

[0046]

According to the present invention, in a method for obtaining a polycarbonate by transesterification between an aromatic dihydroxy compound and a carbonic acid diester compound, a specific compound is contained in a recycled monohydroxy compound by-produced by the reaction for obtaining a polycarbonate. And a polycarbonate having an excellent hue can be produced.

[0047]

[Example 1] [Synthesis of diphenyl carbonate] trimethylamine 1
Phenol 11 containing 0 ppm and 5 ppm anisole obtained by recycling in a melt condensation polymerization method
8 parts by weight, a 48.6% aqueous sodium hydroxide solution and 330.8 parts by weight of ion-exchanged water were charged into a reactor equipped with a stirring blade, a condenser and a gas injection tube, and cooled to 20 ° C. in a water bath. 64 parts by weight of phosgene gas was blown into the reaction tank over 40 minutes with stirring. During this time, the reactor was cooled with a water bath to maintain the internal temperature at 30 ° C. After the phosgene gas was blown in, stirring was continued at room temperature for 3 hours to complete the reaction.
The resulting diphenyl carbonate was collected by filtration, washed three times with 400 parts by weight of ion-exchanged water, and dried under reduced pressure at 50 ° C. for 10 hours. 128 parts by weight of diphenyl carbonate having a melting point of 80 to 81 ° C. were obtained.

Using this, a vacuum distillation apparatus provided with a distillation column, a condenser, and a vacuum suction unit was used.
Distillation and purification were carried out at 0 torr to obtain 115 parts by weight of purified diphenyl carbonate.

[Synthesis of polycarbonate] 115 parts by weight of the purified diphenyl carbonate and 123 parts by weight of bisphenol A obtained above, 1.5 × 10 ^-4 parts by weight of disodium salt of bisphenol A as a transesterification catalyst, and tetramethylammonium Hydroxide4.
9 × 10 ^-2 parts by weight of a stirrer, distillation column, condenser,
After charging into a reaction vessel equipped with a vacuum suction unit and purging with nitrogen,
Melted at 140 ° C. After stirring for 30 minutes, raise the internal temperature to 180 ° C.
And reacted at an internal pressure of 100 torr for 20 minutes.
The phenol formed was distilled off.

Then, while the internal temperature was raised to 200 ° C., the pressure was gradually reduced, and the reaction was carried out at 50 torr for 20 minutes while distilling off phenol. 220 ° C, 30 torr, 240 ° C, 10 torr, 270 ° C, 10 torr
The temperature is increased and reduced to rr, and finally 270
The reaction was performed at 2 ° C. for 1 hour at 1 ° C.

Using the resulting polymer, intrinsic viscosity (ηsp / C) measured in methylene chloride at 20 ° C.
Was 0.50 dl / g. In addition, a 3 mmt injection molded plate was prepared as a polymer hue, and a color color reference made by Nippon Denshoku Industries Co., Ltd. was used.
It was 1.3 as a result of having measured the b value as a thing which showed the yellowness of the polymer with Meter ND-1001DP.

Example 2 Trimethylamine 20 ppm
A polymer was obtained in the same manner as in Example 1 except that phenol obtained by recycling in a melt condensation polymerization method was used. The intrinsic viscosity of the resulting polymer (η
sp / C) is 0.50 dl / g, and the b value is 1.4.
Met.

Example 3 A polymer was obtained in the same manner as in Example 1 except that phenol containing 15 ppm of anisole and obtained by recycling in a melt condensation polymerization method was used. The intrinsic viscosity of the resulting polymer (ηsp /
C) was 0.49 dl / g, and the b value was 1.5.

Comparative Example 1 Trimethylamine 50 ppm
A polymer was obtained in the same manner as in Example 1 except that phenol containing 34 ppm of anisole and obtained by recycling in a melt condensation polymerization method was used. The intrinsic viscosity (ηsp / C) of the resulting polymer is 0.48 dl
/ G, and the b value was 2.5.

Comparative Example 2 A polymer was obtained in the same manner as in Example 1 except that phenol containing 5 ppm of trimethylamine and 0.1 ppm of anisole and obtained by recycling in a melt condensation polymerization method was used. The intrinsic viscosity (ηsp / C) of the resulting polymer is 0.49 dl
/ G, and the b value was 2.0.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Wataru Funakoshi 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi Prefecture Teijin Co., Ltd. Inside the Iwakuni Research Center (72) Inventor Katsushi Sasaki 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi Prefecture Teijin Shares AJ1029 AA10 AB04 AC01 AD01 BB13A HC02 HC05A HC05B JA091 JA121 JA161 JA201 JA261 JA301 JB131 JB143 JB171 JB201 JC033 JC091 JC631 JD06 JF021 JF031 JF041 KA02 KB04 K01

Claims (5)

[Claims] 1. A diester carbonate is synthesized from (I) a monohydroxy compound, a hydroxy compound of an alkali metal and phosgene, and (II) a polycarbonate is produced by a melt condensation polymerization method using the diester carbonate. )) To collect the by-product monohydroxy compound,
The method for producing a polycarbonate which is reused in the step (I), wherein the monohydroxy compound to be reused contains 1 to 1000 ppm of anisole. 2. (I) A diester carbonate is synthesized from a monohydroxy compound, a hydroxy compound of an alkali metal and phosgene, and (II) a polycarbonate is produced by a melt polycondensation method using the diester carbonate. )) To collect the by-product monohydroxy compound,
A method for producing a polycarbonate which is reused in the step (I), wherein the monohydroxy compound to be reused contains 1 to 100 ppm of trimethylamine. 3. A method for preparing a polycarbonate from a monohydroxy compound, a hydroxy compound of an alkali metal and phosgene from a monohydroxy compound, a phosgene, and (II) a polycarbonate by melt condensation polymerization using the carbonate diester. )) To collect the by-product monohydroxy compound,
The method for producing a polycarbonate which is reused in the step (I), wherein the monohydroxy compound to be reused contains 1 to 1000 ppm of anisole and 1 to 100 ppm of trimethylamine. Production method. 4. The method for producing a polycarbonate according to claim 1, wherein the monohydroxy compound is phenol. 5. The catalyst used in the melt condensation polymerization method is a quaternary ammonium salt or a quaternary phosphonium salt and / or an alkali metal salt, or a quaternary ammonium salt or a quaternary phosphonium salt and / or an alkaline earth. The method for producing a polycarbonate according to any one of claims 1 to 4, which is a metal salt.