JPH0967433A - Production of polycarbonate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a polycarbonate resin containing extremely small amount of impurities, especially volatile impurities and excellent in heat stability, color phase stability and hydrolysis resistance. SOLUTION: This polycarbonate resin is produced by melting and kneading a polycarbonate using an extruder having a pressure reducing vent. In this process, 0.1-20 pts.wt. of a saturated aliphatic hydrocarbon is added to 100 pts.wt. of the polycarbonate at the kneading port of the extruder and the polycarbonate is kneaded in the presence of the saturated aliphatic hydrocarbon followed by pressure reduction.

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 resin, and more specifically, it has a very low content of impurities, especially volatile impurities, and is excellent in thermal stability and hue stability.
The present invention relates to a method for producing a polycarbonate resin having excellent hydrolysis resistance.

[0002]

2. Description of the Related Art Polycarbonate has excellent mechanical properties such as impact resistance and transparency, and is widely used for various purposes. Known methods for producing polycarbonate include an interfacial method in which a dihydroxy compound and phosgene are directly reacted, and a melting method in which a dihydroxy compound and a carbonic acid diester are subjected to transesterification under heating and reduced pressure.

The production of a polycarbonate resin is usually carried out by kneading and extruding a polymerized polycarbonate, but the final product of the polycarbonate is volatile such as impurities, particularly raw material components and reaction by-products or solvents. There is a problem that impurities remain. Polycarbonate containing such impurities has problems such as a part of which is thermally decomposed during melt molding to lower the molecular weight, lower transparency, and color.

In order to solve such a problem, a method of kneading and extruding a polycarbonate obtained by polymerization under reduced pressure,
A method of kneading and extruding while adding water, and a method of combining these have been proposed. However, the method of kneading and extruding under reduced pressure is insufficient in the effect of reducing volatile impurities having a high boiling point, and the method of adding water may cause hydrolysis of the polycarbonate, and a satisfactory solution has not yet been obtained. is the current situation.

[0005]

An object of the present invention relates to a method for producing a polycarbonate resin, which has an extremely low content of impurities, particularly volatile impurities, and is excellent in heat stability, hue stability and hydrolysis resistance. It is to provide a method for producing a polycarbonate resin.

[0006]

Means for Solving the Problems That is, the present invention relates to a method for producing a polycarbonate resin by melt-kneading polycarbonate using an extruder having a decompression vent port, wherein 100 parts by weight of polycarbonate is added to the kneading part of the extruder. In the method for producing a polycarbonate resin, 0.1 to 20 parts by weight of a saturated aliphatic hydrocarbon is added, and the polycarbonate is kneaded in the presence of the saturated aliphatic hydrocarbon and then subjected to a reduced pressure treatment.

According to the method for producing a polycarbonate resin of the present invention, it is possible to produce a polycarbonate resin having an extremely small content of impurities, particularly volatile impurities, and to obtain heat stability, hue stability and hydrolysis resistance during molding. It is possible to produce a polycarbonate resin having excellent properties.

In the present invention, polycarbonate obtained by various methods can be used as the polycarbonate supplied to the extruder having a vacuum vent port. For example, a known acid acceptor can be used in a solvent such as methylene chloride. , Those produced by the reaction of a dihydric phenol with a carbonate precursor such as phosgene in the presence of a molecular weight modifier, an aromatic dihydroxy compound and an aromatic carbonic acid diester, in the presence of a polymerization catalyst, in a molten state for transesterification ( Some of them are produced by melt polymerization, and the latter is particularly preferable because a large effect can be obtained as compared with the conventional method.

The aromatic dihydroxy compound used in the melt polymerization is not particularly limited, but for example, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2 2-bis (4
-Hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxy-t-butylphenyl) propane, etc. Bis (hydroxyaryl) alkanes, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1
-Bis (hydroxyaryl) cycloalkanes such as bis (hydroxyphenyl) cyclohexane, 4,4 '
-Dihydroxy aryl ethers such as dihydroxy diphenyl ether, dihydroxy aryl sulfides such as 4,4'-dihydroxy diphenyl sulfide, dihydroxy aryl sulfoxides such as 4,4'-dihydroxy diphenyl sulfoxide, 4,4'-
Dihydroxyaryl sulfones such as dihydroxydiphenyl sulfone are used. Particularly, 2,2-bis (4-hydroxyphenyl) propane is preferable.

Examples of the aromatic carbonic acid diester used in the melt polymerization include optionally substituted esters such as aryl groups having 6 to 10 carbon atoms and aralkyl groups. Specific examples include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, and the like.

The aromatic carbonic acid diester as described above is added in an amount of 1.00 to 1.
It is used in an amount of 30 mol, preferably 1.005 to 1.10 mol.

In the melt polymerization, a polymerization catalyst can be used for accelerating the polymerization rate when producing a polycarbonate by the transesterification reaction between the aromatic dihydroxy compound and the aromatic carbonic acid diester as described above.

Such a polymerization catalyst comprises an alkali metal compound and an alkaline earth metal compound as main components, and a nitrogen-containing basic compound as a secondary component, if necessary.

The alkali metal compounds 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 stearate, potassium stearate, lithium stearate, sodium salt of bisphenol A, potassium salt, lithium salt, sodium benzoate, potassium benzoate, lithium benzoate and the like.

Examples of the alkaline earth metal compound include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate and carbonic acid. Examples thereof include magnesium, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate.

Examples of the nitrogen-containing basic compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylamine, triethylamine, dimethylbenzylamine, triphenylamine and the like.

The above-mentioned polymerization catalysts may be used alone or in combination.

In the case of using an alkali metal compound and / or an alkaline earth metal compound, the amount of these polymerization catalysts used is 1 × 10 ^-7 to 1 per 1 mol of the aromatic dihydroxy compound.
It is selected in the range of x10 ^-4 equivalent, preferably 1 x 10 ^{-6 to} 5 x 10 ^-5 equivalent.

When a nitrogen-containing basic compound is used as a secondary component, 1 × 10 ⁻⁵ to 1 × 10 ⁻³ equivalent, preferably 1 × 10 ⁵ equivalent to 1 mol of the aromatic dihydroxy compound is used.
^{-5 to} 5 x 10 ^-4 equivalents are selected.

When the nitrogen-containing basic compound is used in combination with the alkali metal compound and / or the alkaline earth metal compound, the preferable amount of use corresponds to the sum of the above ranges, and it is 1 per 1 mol of the aromatic dihydroxy compound. × 10
^-7 to 1 x 10 ^-3 equivalent, preferably 1 x 10 ^{-6 to} 5 x 1
^0-4 equivalents are chosen.

In the melt polymerization, other compounds can be used as an auxiliary catalyst if necessary. Examples of such compounds include alkali metal or alkaline earth metal salts of hydroxides of boron and aluminum, quaternary ammonium salts,
Alkali metal and alkaline earth metal alkoxides, alkali metal and alkaline earth metal organic acid salts, zinc compounds, boron compounds, silicon compounds, germanium compounds, organotin compounds, lead compounds, osmium compounds It is possible to use catalysts which are usually used for esterification reaction and transesterification reaction of compounds, antimony compounds, zirconium compounds and the like, but not limited thereto. When using a co-catalyst, only 1 type may be used and 2 or more types may be used in combination.

Melt polymerization is carried out by distilling an aromatic monohydroxy compound produced by stirring under heating in an inert gas atmosphere as is conventionally known. The reaction temperature is usually in the range of 120 to 350 ° C., and in the latter stage of the reaction, the degree of vacuum of the system is increased to 10 to 0.1 Torr to facilitate the distillation of the aromatic monohydroxy compound produced and complete the reaction.

In the present invention, the polycarbonate supplied to the extruder having a pressure reducing vent may be in any form, for example, powder state, pellet state, and molten state. In the case of polycarbonate obtained by interfacial polymerization, Is a powder, and in the case of a polycarbonate obtained by melt polymerization, it is generally supplied in a molten state. The intrinsic viscosity of polycarbonate is preferably 0.3 or more.

The polycarbonate as described above is kneaded and extruded to produce a polycarbonate resin having a low content of volatile impurities, but a stabilizer may be added in advance. Particularly in the case of a polycarbonate obtained by melt polymerization containing a polymerization catalyst, it is preferable to add a stabilizer to improve the heat resistance.

Known stabilizers are effectively used as such stabilizers, and among these, ammonium salts of sulfonic acids, phosphonium salts of sulfonic acids, and esters of sulfonic acids are preferable.

An ester of dodecylbenzene sulfonic acid,
It is also possible to use an ammonium salt, a phosphonium salt, an ester of paratoluenesulfonic acid, an ammonium salt, a phosphonium salt, an ester of benzenesulfonic acid, an ammonium salt or a phosphonium salt.

Particularly preferred are dodecylbenzenesulfonic acid tetrabutylphosphonium salt and paratoluenesulfonic acid tetrabutylammonium salt.

As sulfonic acid esters, methyl benzene sulfonate, ethyl benzene sulfonate, butyl benzene sulfonate, octyl benzene sulfonate, phenyl benzene sulfonate, methyl paratoluene sulfonate, ethyl paratoluene sulfonate, paratoluene sulfonate Butyl, octyl p-toluenesulfonate, phenyl p-toluenesulfonate and the like are preferably used.

The amount of the stabilizer added to the polycarbonate obtained by melt polymerization is 0.5 to 50 moles per 1 mole of the main polycondensation catalyst selected from alkali metal compounds and alkaline earth metal compounds, preferably 0.5-1
It is used in a proportion of 0 mol, more preferably in a proportion of 0.8 to 5 mol. This is usually 0.
It is equivalent to use at a rate of 01 to 500 ppm.

In the present invention, the polycarbonate thus obtained is fed to an extruder having a vacuum vent port, and the kneading part of the extruder is filled with 0.1 parts of saturated aliphatic hydrocarbon per 100 parts by weight of the polycarbonate. ˜20 parts by weight is added, and the polycarbonate is kneaded in the presence of a saturated aliphatic hydrocarbon and then subjected to a reduced pressure treatment.

The extruder has a unit processing zone consisting of a kneading section, a sealing section and a depressurizing section. The number of unit processing zones may be one, but it is preferable to have a plurality.

A paddle type stirring blade is installed in the kneading section to knead the polycarbonate. The saturated aliphatic hydrocarbon addition port is preferably installed upstream in the traveling direction of the polycarbonate in the kneading section.

The seal portion is located between the kneading portion and the depressurizing portion and has a function of maintaining the depressurized state of the depressurizing portion.

A vent port is installed in the decompression unit, and the decompression unit is kept decompressed by a vacuum pump or the like.

The saturated aliphatic hydrocarbon is added in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the polycarbonate resin. If the amount of saturated aliphatic hydrocarbon added is less than 0.1 parts by weight, the removal of volatile impurities will be insufficient, while if it exceeds 20 parts by weight, impurities will be removed relative to the amount of saturated aliphatic hydrocarbon added. It is economically disadvantageous because the effect does not increase.

When a plurality of unit treatment zones are provided, it is preferable that the amount of saturated aliphatic hydrocarbon added in each zone be within the above range.

The saturated aliphatic hydrocarbon has a boiling point of 30 to 270 ° C., preferably 50 to 200 ° C. at room temperature and atmospheric pressure.
More preferably, one having a temperature of 50 to 150 ° C. is used.

As such a saturated aliphatic hydrocarbon,
2-methylbutane, pentane, 2,2-dimethylbutane, 2,3-dimethylbutane, hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4- Dimethyl pentane, 3,3-dimethyl pentane, heptane, 2-methylhexane, 3-methylhexane, 2,2,3-trimethylbutane, 2,2-dimethylhexane, 2,5-dimethylhexane, 3,4- Dimethylhexane, hexamethylethane, 2-methylheptane, 4-methylheptane,
Octane, 2,2,4-trimethylpentane, 2,3
4-trimethylpentane, nonane, decane, undecane, dodecane, tridecane, tetradecane, 1-pentadecane and the like can be mentioned.

In the present invention, the time for kneading the polycarbonate in the presence of the saturated aliphatic hydrocarbon is defined by the average residence time of the polycarbonate in the kneading section. In the case of an extruder having a plurality of unit processing zones, which is expressed as the sum thereof, it is preferably 0.1 to 100 seconds. If the time for kneading in the presence of a saturated aliphatic hydrocarbon is shorter than this, the effect of removing impurities is reduced, which is not preferable. On the other hand, if the length is longer than this, there is no particular problem in terms of quality, but the production amount decreases.

The temperature condition during kneading of polycarbonate is 2
It is carried out at a temperature of 00 ° C to 350 ° C, preferably 220 ° C to 300 ° C. When the temperature of the polycarbonate resin is lower than 200 ° C, it is difficult to knead the saturated aliphatic hydrocarbon and the polycarbonate resin, whereas when the temperature exceeds 350 ° C, the polycarbonate resin is thermally decomposed, which is not preferable.

In the depressurizing section, the volatile impurities existing in the saturated aliphatic hydrocarbon and the polycarbonate added in the kneading section are depressurized by a vacuum pump or the like and removed. As the reduced pressure treatment condition, 0.1 to 700 mmHg, preferably 1 to 500 mmHg is used.

The residence time of the polycarbonate in the decompression section of the unit processing zone is about 0.1 to 10 seconds.

By such a reduced pressure treatment, while preventing the conventional hydrolysis of the polycarbonate resin, impurities remaining in the polycarbonate final product, particularly raw material components and reaction by-products or volatile impurities such as a solvent Can be effectively removed.

Further, even if the added stabilizer contains a volatile compound or a thermal decomposition product is produced by thermal decomposition, it can be simultaneously removed by a reduced pressure treatment.

In the present invention, a polycarbonate resin having an extremely low content of impurities, particularly volatile impurities, can be produced, and a polycarbonate resin excellent in heat stability during molding, hue stability and hydrolysis resistance can be obtained. It can be manufactured. In addition, the quality of the polycarbonate molded product thus produced is significantly improved.

The shape of the polycarbonate supplied to the extruder is not particularly limited. For example, after adding the stabilizer shown above, while the polycarbonate is in a molten state, these may be fed to an extruder and continuously subjected to a reduced pressure treatment. Further, the above-mentioned stabilizer-added polycarbonate may be pelletized once and then remelted and supplied. In the latter, since the stabilizers shown above are already contained, thermal stability at the time of melting, hue stability, hydrolysis resistance, etc. are improved, and even if re-melting, the thermal decomposition of the polycarbonate is particularly high. It is suppressed and the molecular weight does not easily decrease. Further, the polycarbonate is less likely to cause problems such as deterioration in transparency and coloring.

In the present invention, the polycarbonate to which the above-mentioned stabilizer has been added is fed to the extruder, saturated aliphatic hydrocarbons are added to the kneading section, and then pelletized under reduced pressure.

[0048]

According to the present invention, the reaction product polycarbonate is fed to an extruder having a reduced pressure vent port,
Impurities, especially volatile, are added to the kneading part by adding 0.1 to 20 parts by weight of saturated aliphatic hydrocarbon to 100 parts by weight of polycarbonate, kneading in the presence of saturated aliphatic hydrocarbon, and then reducing the pressure. A polycarbonate resin having an extremely low content of impurities can be produced, and a polycarbonate resin having excellent heat stability during molding, hue stability, and hydrolysis resistance can be produced.

[0049]

EXAMPLES The present invention will be described below with reference to examples. The ppm in the examples is ppm by weight unless otherwise specified. In the following examples, the physical properties of polycarbonate were measured as follows. Intrinsic viscosity is 0.7
A g / dl methylene chloride solution was measured using an Ubbelohde viscometer. The pellet color was measured with a color difference meter manufactured by Nippon Denshoku Industries. Residual impurities in polycarbonate resin,
The amount of phenol, the amount of bisphenol A, and the amount of diphenyl carbonate were measured by high performance liquid chromatography manufactured by Tosoh.

[Examples 1 to 8] Diphenyl carbonate was charged in a melting tank equipped with a stirrer at a ratio of 1.05 mol to 1 mol of 2,2-bis (4-hydroxyphenyl) propane, and after nitrogen substitution. Melted at 150 ° C.

Then, the molten mixture was transferred to a vertical stirring tank equipped with a rectification column, and 2 × 10 ^-6 equivalent of bisphenol A di was added to 1 mol of 2,2-bis (4-hydroxyphenyl) propane. Sodium salt and 1 × 10 ⁻⁴ equivalent of tetramethylammonium hydroxide were added, and the reaction temperature was 1
While maintaining the reaction pressure at 100 ° C and the reaction pressure at 80 ° C, the produced phenol was removed from the rectification column to carry out the reaction, and then the initial temperature polymerization was performed at 200 ° C and the reaction pressure of 30 mmHg.

Then, the polymer after the initial polymerization was supplied to a vertical stirring tank having no rectification column maintained at 270 ° C. and 1 mmHg to produce a polycarbonate with an intrinsic viscosity of 0.35 as a target.

Next, dodecylbenzenesulfonic acid tetrabutylphosphonium salt as a stabilizer was added to the molten resin in an amount of 20 ppm with respect to the polycarbonate, and the whole amount was pelletized after mixing for 0.5 hours under reduced pressure.

The intrinsic viscosity of the obtained pellets is 0.34
8, the hue b value is 0.1, the phenol content is 18
0 ppm, bisphenol A content was 100 ppm, and diphenyl carbonate content was 220 ppm.

The obtained polycarbonate was subjected to a table using a 30 mm 3-stage vented 3-stage addition twin-screw extruder (unit treatment zone number = 3) and heptane as a saturated aliphatic hydrocarbon. The mixture was extruded under reduced pressure under the kneading and extrusion conditions shown in 1 to 3, and pelletized. Tables 1 to 3 show the measurement results of the residual phenol amount, bisphenol A amount, diphenyl carbonate amount, intrinsic viscosity, and hue b value in the obtained polycarbonate resin.

Example 9 The same procedure as in Examples 1 to 8 was repeated except that the amount of tetrabutylammonium paratoluenesulfonate shown in Table 4 was used as a stabilizer and kneading was carried out under the kneading conditions shown in Table 4. A polycarbonate resin was produced.
The amount of residual phenol in the obtained polycarbonate resin,
Table 4 shows the measurement results of the amount of bisphenol A, the amount of diphenyl carbonate, the intrinsic viscosity, and the hue b value.

Example 10 Polycarbonate resins were prepared in the same manner as in Examples 1 to 8 except that butyl paratoluenesulfonate in the amount shown in Table 5 was used as a stabilizer and kneading was carried out under the kneading conditions shown in Table 5. Manufactured. Residual phenol amount in the obtained polycarbonate resin, bisphenol A
Table 5 shows the measurement results of the amount, the amount of diphenyl carbonate, the intrinsic viscosity, and the hue b value.

[Comparative Examples 1 to 4] Polymerization was carried out in Examples 1 to 8 and the polycarbonate to which the stabilizer was added was the same 30 m.
In the kneading extrusion conditions shown in Tables 6 and 7, using a three-stage vented three-stage vented twin-screw extruder (unit treatment zone number = 3) and using heptane as a saturated aliphatic hydrocarbon. It was vacuum treated and pelletized. Tables 6 and 7 show the measurement results of the amount of residual phenol, the amount of bisphenol A, the amount of diphenyl carbonate, the intrinsic viscosity, and the hue b value in the obtained polycarbonate resin.

[Comparative Example 5] Polymerization was carried out in Examples 1 to 8,
Using a polycarbonate with a stabilizer added, using the same 30 mm three-stage vented three-stage addition twin screw extruder (unit treatment zone number = 3), using water instead of saturated aliphatic hydrocarbon, The mixture was extruded under reduced pressure under the kneading and extrusion conditions shown in Table 8 and pelletized. Table 8 shows the measurement results of the residual phenol amount, bisphenol A amount, diphenyl carbonate amount, intrinsic viscosity, and hue b value in the obtained polycarbonate resin.

[Comparative Example 6] Polymerization was carried out in Examples 1 to 8,
The polycarbonate to which the stabilizer is added is shown in Table 9 using the same 30 mm 3-stage vented 3-stage twin-screw extruder (unit treatment zone number = 3) without addition of saturated aliphatic hydrocarbon. The mixture was kneaded and extruded under reduced pressure to be pelletized. Table 9 shows the measurement results of the residual phenol amount, bisphenol A amount, diphenyl carbonate amount, intrinsic viscosity, and hue b value in the obtained polycarbonate resin.

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

[Table 3]

[0064]

[Table 4]

[0065]

[Table 5]

[0066]

[Table 6]

[0067]

[Table 7]

[0068]

[Table 8]

[0069]

[Table 9]

Claims (8)

[Claims] 1. A method for producing a polycarbonate resin by melt-kneading a polycarbonate using an extruder having a vacuum vent port, wherein a saturated aliphatic hydrocarbon is added to the kneading part of the extruder at 0.1 parts by weight per 100 parts by weight of the polycarbonate. ~
A method for producing a polycarbonate resin, which comprises adding 20 parts by weight, kneading a polycarbonate in the presence of a saturated aliphatic hydrocarbon, and then subjecting it to a reduced pressure treatment. 2. The method according to claim 1, wherein the saturated aliphatic hydrocarbon has a boiling point of 30 to 270 ° C. at room temperature and atmospheric pressure. 3. The method according to claim 1, wherein the polycarbonate is a polycarbonate obtained by melt-polymerizing an aromatic dihydroxy compound and an aromatic carbonic acid diester. 4. The alkali metal compound and / or the alkaline earth metal compound and the nitrogen-containing basic compound in a proportion of 1 × 10 ⁻⁷ to 1 × 10 ⁻³ equivalent of the polycarbonate with respect to 1 mol of the aromatic dihydroxy compound. 2. A polycarbonate obtained by melt-polymerizing in the presence of a polymerization catalyst consisting of 1) and a stabilizer added in a proportion of 0.01 to 500 ppm.
The manufacturing method according to any one of to 3. 5. The method according to claim 4, wherein at least one selected from the group consisting of ammonium salts of sulfonic acid, phosphonium salts of sulfonic acid and esters of sulfonic acid is used as the stabilizer. . 6. The production method according to claim 4, wherein at least one selected from the group consisting of dodecylbenzenesulfonic acid ester, ammonium salt, and phosphonium salt is used as a stabilizer. 7. The stabilizer is at least one selected from the group consisting of esters of paratoluene sulfonic acid, ammonium salts, phosphonium salts, esters of benzene sulfonic acid, ammonium salts and phosphonium salts. The manufacturing method according to claim 4. 8. Kneading of polycarbonate at a temperature of 200
8. Kneading in the presence of a saturated aliphatic hydrocarbon at .about.350.degree. C. for 0.1 to 100 seconds, and then treating under a reduced pressure of 0.1 to 700 mmHg. The manufacturing method described.