JPH11335458A - Aromatic-aliphatic copolycarbonate and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject copolycarbonate scarcely containing foreign materials, capable of manifesting excellent impact, heat and weather resistances and transparency, having a high Abbe's number and a low photoelastic constant, further capable of manifesting an excellent color tone and useful for optical lenses, etc., by specifying the numbers of the foreign materials for the particle diameter distribution. SOLUTION: A polycarbonate comprising a constituent unit represented by formula I [X is a group represented by formula II (R3 and R4 are each H, a 1-10C alkyl or the like), O, S or the like; R1 and R2 are each H, an alkyl or the like; (m) and (n) are each 0-4] and a constituent unit represented by formula III (R5 and R8 are each H or a 1-10C alkyl) is regulated so that respective numbers of foreign materials having >=10 μm particle diameter, 1-10 μm particle diameter and 0.5-1 μm particle diameter in 1 g of the copolycarbonate are <=100, <=5,000 and <=1×10<5> . The copolycarbonate is produced by carrying out the melt polycondensation of, e.g. the corresponding aromatic dihydroxy compound with the corresponding aliphatic dihydroxy compound and a carbonic diester in the presence of a basic catalyst by installing a filter before or after a polymerization reactor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a transparent aromatic-aliphatic copolymer polycarbonate having a small amount of foreign matter, high impact resistance, high refractive index and inverse dispersion value, low photoelastic constant and excellent hue. And its manufacturing method. This polycarbonate can be suitably used for optical materials such as various lenses, prisms, optical disk substrates, and optical fibers.

[0002]

2. Description of the Related Art A polycarbonate obtained by interfacial polymerization of an aromatic dihydroxy compound such as bisphenol A and phosgene in the presence of an acid binder is excellent in mechanical properties such as impact resistance, heat resistance and transparency. It is used as an optical material for various lenses, prisms, optical disk substrates, and the like. However, in the polycarbonate using only bisphenol A as the aromatic dihydroxy compound, the photoelastic constant is large and the melt fluidity is relatively poor, so that the birefringence of the molded product becomes large, and the refractive index is as high as 1.58. Abbe number is 30
Therefore, there is a drawback that it does not have sufficient performance to be widely used for applications such as optical recording materials and optical lenses. For the purpose of solving such a drawback of bisphenol A-polycarbonate, the inventors of the present invention have previously proposed aromatic-
Aliphatic copolymer polycarbonate (Japanese Patent Application No. 8-27626)
0) was proposed. This aromatic-aliphatic copolymerized polycarbonate has excellent impact resistance and heat resistance, and furthermore has a small photoelastic constant and a high Abbe number, so that it can be widely used as an optical material. The aromatic-aliphatic copolymerized polycarbonate is difficult to produce by a normal phosgene method, and is a method known as a transesterification method, that is, an aromatic dihydroxy compound and an aliphatic dihydroxy compound, and a carbonate diester such as diphenyl carbonate. Is preferably used in a polycondensation reaction by transesterification in the molten state.

However, when the transesterification reaction is carried out in a normal environment under a normal procedure, foreign substances floating in the environment or foreign substances originally contained in the raw materials are taken into the reaction system, and the final product is produced. It is directly mixed into a certain polycarbonate. In addition, foreign substances floating in the environment are mixed in all processes such as mixing of additives, pelletizing, drying, and bagging. Therefore, lenses, prisms, disks, and the like formed by molding polycarbonate containing a large amount of such foreign substances have a reduced light transmittance, and also have a high haze value. In some cases, foreign matters giving an unpleasant impression in appearance are sometimes found, and improvement has been desired.

When the aromatic-aliphatic copolymerized polycarbonate is produced by a transesterification reaction, a temperature of 200 ° C.
In order to perform polycondensation while heating to a temperature of ~ 300 ° C,
It is difficult to completely avoid the generation of fine gel-like foreign matter due to a side reaction due to a long-term heat history at a high temperature. In addition, it is difficult to completely avoid the generation of fine gel-like foreign matter that is generated in the portion where the resin residence time of the stirring blade of the extruder-type kneader is long during the kneading of the additive. Since such a gel-like foreign matter is also mixed into the polymer of the final product, it causes poor light transmittance, high haze, and poor appearance of the same molded product as described above, and a molded product excellent in quality. Is difficult to obtain.

[0005]

SUMMARY OF THE INVENTION The present invention seeks to solve the problems associated with the prior art as described above.
The aromatic substance having few foreign matters, excellent impact resistance, excellent heat resistance, high Abbe number, low photoelastic constant, and excellent color tone.
An object is to provide an aliphatic polycarbonate and a method for producing the same.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve these problems, and as a result, the following formula (1)
In an aromatic-aliphatic copolymer polycarbonate comprising a structural unit represented by the following formula and a structural unit represented by the following formula (2), the number of foreign substances having a size of 10 μm or more contained in 1 g of the polycarbonate is 100 or less, Size 1μm
By setting the number of foreign substances having a size of not less than 10 μm to 5,000 or less and the number of foreign substances having a size of 0.5 μm to less than 1 μm to 1 × 10 ⁵ or less, light transmittance is excellent, haze is low, and appearance is low. The inventors have found that an excellent aromatic-aliphatic copolymer polycarbonate resin molded article can be obtained, and have reached the present invention.

Embedded image (In the above formula (1), X is

Embedded image Wherein R ₃ and R ₄ are each a hydrogen atom,
An alkyl group having 1 to 10 carbon atoms or a phenyl group,
R ₃ and R ₄ may combine to form a ring. R ₁ and R ₂ are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or halogen, and R ₁ and R ₂ may be the same or different. Further, m and n represent the number of substituents and are integers of 0 to 4. )

Embedded image (In the above formula (2), R ₅ , R ₆ , R ₇ and R ₈ are each a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.)

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the aromatic-aliphatic copolymer polycarbonate and the method for producing the same according to the present invention will be described in detail.

The aromatic-aliphatic copolycarbonate of the present invention is a polycarbonate having excellent light transmittance, low haze value, and gives a molded article excellent in clear feeling and appearance and with little foreign matter.

When the molded article is required to have excellent appearance, clear feeling, and low haze value when visually observed such as a lens or a prism, the aromatic-aliphatic copolymer polycarbonate 1
The amount of foreign matter in g is 1 with the number of foreign matter having a size of 10 μm or more.
00 or less, more preferably 50 or less, and 5000 or less foreign matters having a size of 1 μm or more and less than 10 μm,
More preferably 2,000 or less, 0.5 μm in size
By setting the number of foreign substances having a particle size of 1 μm or less to 1 × 10 ⁵ or less, more preferably 5 × 10 ⁴ or less, the molded article has practically no unpleasant appearance, clear feeling, and low haze value. And can be suitably used.

When the molded article is a disk substrate, optical fiber, or the like, the foreign matter impedes transmission of light and directly causes an information writing error or a transmission error. Is 0 in the number of foreign substances having a size of 10 μm or more, and 1000 or less in the number of foreign substances having a size of 1 μm or more and less than 10 μm.
More preferably, the number is 600 or less, and the number of foreign matters having a size of 0.5 μm or more and less than 1 μm is 5 × 10 ⁴ or less, more preferably 2 × 10 ⁴ or less. Can be reduced to a level that does not cause a practical problem, and the device can be used preferably.

During the production of the aromatic-aliphatic copolymerized polycarbonate, the entire production equipment such as a reactor, an additive kneader, an aqueous layer, and a pelletizer is installed in a clean booth in order to minimize the contamination of foreign substances from the environment. In addition, the rotating device and the worker, which are the sources of foreign matter, take dust-proofing measures so as not to diffuse the foreign matter into the clean booth. Nitrogen used in the reaction is used after removing foreign substances with a gas filter. However, it is preferable that the raw material dissolving tank for charging the powder is installed outside the clean booth. Clean booth cleanliness
Preferably class 1000, more preferably class 10
0.

The aromatic-aliphatic copolycarbonate according to the present invention comprises a structural unit (hereinafter referred to as I) derived from an aromatic dihydroxy compound represented by the above formula (1) and a compound represented by the above formula (2). It is composed of a structural unit (hereinafter referred to as II) derived from an aliphatic dihydroxy compound represented by the formula, is a random, block, or alternating copolymer, has excellent impact resistance and heat resistance, and has physical properties such as a refractive index and an Abbe number. It is an optical material with excellent balance.

In the present invention, the molar ratio (I / II) of the structural units derived from the aromatic dihydroxy compound and the aliphatic dihydroxy compound is 90 /.
It is preferably 10 to 10/90, and more preferably 80/20 to 20/80. That is, the molar ratio (I / II) of the structural units derived from the aromatic dihydroxy compound and the aliphatic dihydroxy compound is 10/9.
If it is lower than 0, the heat resistance is inferior, and if it is higher than 90/10, the photoelastic constant, the water absorption and the like increase, and the balance between the refractive index and the Abbe number deteriorates.

In the present invention, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, etc. are used as the carbonic acid diester. . Among these, diphenyl carbonate is particularly preferred. Diphenyl carbonate is used in an amount of 0.97 to 0.9 mol based on a total of 1 mol of the aromatic dihydroxy compound and the aliphatic dihydroxy compound.
It is preferably used in an amount of 1.2 mol, particularly preferably 0.99 to 1.10 mol.

The weight average molecular weight of the aromatic-aliphatic copolymer polycarbonate according to the present invention is 30,000 to 20.
It is preferably 0000, more preferably 5
It is between 0000 and 120,000.

The aromatic-aliphatic copolymer polycarbonate resin is produced by a melt polycondensation method. That is, by-products are produced under heating at normal pressure or reduced pressure using an aromatic dihydroxy compound represented by the following formula (3), an aliphatic dihydroxy compound represented by the following formula (4), a carbonic acid diester and a catalyst. Melt polycondensation is performed while removing.
The reaction is generally carried out in two or more stages.

[0017]

Embedded image (In the above formula (3), X is

Embedded image Wherein R ₃ and R ₄ are each a hydrogen atom,
An alkyl group having 1 to 10 carbon atoms or a phenyl group,
R ₃ and R ₄ may combine to form a ring. R ₁ and R ₂ are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or halogen, respectively, and R ₁ and R ₂ may be the same or different. M and n represent the number of substituents and
4 is an integer. )

Embedded image (In the above formula (4), R ₅ , R ₆ , R ₇ and R ₈ are each a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms.)

Specifically, the first-stage reaction is carried out at 120 to 260
The reaction is carried out at a temperature of 180C, preferably 180 to 240C for 0 to 5 hours, preferably 0.5 to 3 hours. Next, the degree of reaction is increased while increasing the degree of vacuum of the reaction system, and finally the polycondensation reaction is carried out at a temperature of 200 to 300 ° C. under a reduced pressure of 1 mmHg or less. In addition, a vertical reactor, a horizontal reactor, or an appropriate combination thereof is used as a reactor used for performing the above reaction.

As the polymerization catalyst, a basic compound is used. Examples of such a basic compound include an alkali metal compound, an alkaline earth metal compound, a nitrogen-containing compound and the like, and these compounds can be used alone or in combination.

As such an alkali metal compound,
Organic acid salts of inorganic metals, inorganic acid salts, oxides, hydroxides, hydrides, alcoholates and the like are used, and specifically, sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, hydrogen carbonate Sodium, potassium bicarbonate, lithium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, lithium carbonate, sodium acetate,
Potassium acetate, cesium acetate, lithium acetate, sodium stearate, potassium stearate, cesium stearate, lithium stearate, sodium borohydride, lithium borohydride, sodium borohydride, sodium benzoate, potassium benzoate, benzoic acid Cesium, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium phenylphosphate, dipotassium phenylphosphate, dilithium phenylphosphate, disodium salt of bisphenol A, 2 Potassium salts, dicesium salts, dilithium salts, sodium salts of phenol, potassium salts, cesium salts, lithium salts and the like are used.

Further, as the alkaline earth metal compound,
Alkaline earth metal organic acid salts, inorganic acid salts, oxides, hydroxides, hydrides, alcoholates and the like are used, specifically, 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, barium acetate, magnesium acetate, strontium acetate,
Calcium stearate, barium stearate, magnesium stearate, strontium stearate,
Are used.

As the nitrogen-containing compound, quaternary ammonium hydroxides, quaternary ammonium salts, amines and the like are used. Specifically, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutyl Ammonium hydroxides, ammonium hydroxides having alkyl, aryl, allylaryl groups and the like such as trimethylbenzylammonium hydroxide, tertiary amines such as trimethylamine, triethylamine, dimethylbenzylamine and triphenylamine, dimethylamine and diethylamine; Secondary amines such as methylamine, primary amines such as ethylamine, imidazoles such as 2-methylimidazole and 2-phenylimidazole, or ammonia; Basic salts such as tetramethylammonium borohydride, tetrabutylammonium borohydride, tetrabutylammonium tetraphenylborate, tetramethylammonium tetraphenylborate and the like are used.

These catalysts are used in an amount of 10 ^-9 to 10 mol per 1 mol of the aromatic dihydroxy compound represented by the above formula (3) and the aliphatic dihydroxy compound represented by the above formula (4) in total.
An amount of 10 ^-3 mol is used, preferably an amount of 10 ^-7 to 10 ^-5 mol.

As the aromatic dihydroxy compound represented by the above formula (3), specifically, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis ( 4-hydroxyphenyl) propane, 2,2-
Bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1 , 1-bis (4-hydroxy-3-
t-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethylphenyl ether, 4,4'-dihydroxyphenyl sulfide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, 4,4'-dihydroxydiphenylsulfoxide,
4,4'-dihydroxy-3,3'-dimethyldiphenylsulfoxide, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone and the like. Among these, in particular 2,2-bis (4-hydroxyphenyl) propane, ie bisphenol A or
1,1-bis (4-hydroxyphenyl) cyclohexane is preferred.

As the aliphatic dihydroxy compound represented by the above formula (4), specifically, (3,9-bis (2-hydroxyethyl) -2,4,8,10-tetraoxaspiro ( Five.
5) Undecane), (3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane), (3,9-bis (2- (Hydroxy-1,1-diethylethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane), (3,9-bis (2-hydroxy-1,1-dipropylethyl) -2,4 , 8,10-tetraoxaspiro (5.5) undecane) and the like. Preferably, (3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane) is used. Preferably, (3,9-bis (2-hydroxyethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane) is used.

Further, as the carbonic diester, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate Are used. Of these, diphenyl carbonate is particularly preferred. The carbonic acid diester is preferably used in an amount of 1.01 to 1.30 mol with respect to a total of 1 mol of the aromatic dihydroxy compound (3) and the aliphatic dihydroxy compound (4).

In the present invention, in order to remove the aromatic dihydroxy compound, the aliphatic dihydroxy compound, the carbonic acid diester, and the foreign matter in the catalyst, which are the raw materials, a filter is connected in the middle of the pipe connecting the raw material dissolving tank and the reactor. It is preferable to perform filtration. A plurality of reactors may be used in succession in the polymerization reactor, and a combination of at least one or more vertical reactors and at least one or more horizontal reactors is suitably used. in this case,
The filtration may be performed at any stage before the final reactor where the viscosity of the reaction solution is relatively low. The absolute filtration accuracy of the filter is preferably 0.5 μm or more and 2 μm or less. If the absolute filtration accuracy exceeds 2 μm, foreign substances in the raw material and the catalyst cannot be sufficiently removed, and foreign substances in the reaction product increase, which is not preferable.

At least one filter is provided. When the filter is clogged, supply of the raw material is stopped and the filter is replaced.However, in the low-viscosity region, there are few stagnation points of the reaction solution in the piping portion when a plurality of filters are arranged in parallel. It is also possible to install two or more filters in parallel and use them alternately.

In the present invention, it is preferable to provide a filter at the outlet of the reactor in order to remove fine gel-like foreign matter generated as a side reaction during the transesterification reaction.
The absolute filtration accuracy of the filter is preferably from 2 μm to 30 μm, more preferably from 2 μm to 20 μm.
m or less.

In the polycarbonate of the present invention, it is preferable to remove or deactivate the catalyst in order to maintain thermal stability and hydrolysis stability. In general, a method of deactivating a transesterification catalyst such as an alkali metal or an alkaline earth metal by adding a known acidic substance is suitably performed. Specific examples of these substances include p
-Aromatic sulfonic acid esters such as toluenesulfonic acid, aromatic sulfonic acid esters such as butyl paratoluenesulfonate, organic halides such as stearic acid chloride, butyric acid chloride, benzoyl chloride, and toluenesulfonic acid chloride; and dimethyl sulfate. Organic halides such as alkyl sulfates and benzyl chloride are preferably used.

After deactivation of the catalyst, low-boiling compounds in the polymer are removed.
A step of devolatilization and removal at a pressure of 0.1 to 1 mmHg and a temperature of 200 to 300 ° C. may be provided. For this purpose, paddle blades, lattice blades,
A horizontal kneader or a thin film evaporator having eyeglasses or the like is preferably used.

In the present invention, the above-mentioned heat stabilizer,
In addition to the hydrolysis stabilizer, antioxidants, pigments, dyes, reinforcing agents and fillers, ultraviolet absorbers, lubricants, release agents, crystal nucleating agents, plasticizers, flow improvers, antistatic agents, etc. Can be added. Further, for the purpose of further improving the properties of the resin, another polycarbonate resin or a thermoplastic resin may be blended and used.

The kneading of these additives is preferably carried out by directly feeding a resin obtained by polymerization from a reactor to a kneading machine with a gear pump and kneading with a stirring blade such as a screw. After pelletizing the polymer, the additives may be kneaded. At the time of kneading, the resin present in the stagnant portion of the kneader generates a gel-like foreign matter and contaminates the resin. The absolute filtration accuracy of the filter is
Preferably it is 2 μm or more and 50 μm or less, more preferably 5 μm or more and 30 μm or less.

[0034]

According to the present invention, an aromatic-aliphatic copolymer having a small amount of foreign matter, excellent impact resistance, heat resistance, weather resistance and transparency, and having a high Abbe number and a low photoelastic constant and excellent color tone. It is possible to produce a large amount of a polymerized polycarbonate, and it can be supplied to a wide range of optical transparent material fields such as spectacle lenses, prisms, optical disc substrates, and optical fibers that require excellent color tone and a small amount of foreign matter.

[0035]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples. The reactors were all installed in a class 1000 clean booth except for the raw material dissolving tank, and the physical properties were measured by the following methods. (1) Weight average molecular weight Mw: Measured as polystyrene equivalent molecular weight by GPC (Shodex System-11, column temperature 40 ° C.) using chloroform as a solvent. (2) YI (yellow index): The polymer was injection-molded into a disk having a diameter of 45 mm and a thickness of 3 mm, and measured by a color difference meter (Tokyo Denshoku TC-1800MK). (3) Foreign substance measurement: For foreign substances having a size of 0.5 μm or more and 25 μm or less, 1 g of an aromatic-aliphatic copolymer polycarbonate
Was dissolved in 100 ml of methylene chloride and measured using a light scattering particle size sensor. For foreign substances exceeding 25 μm, 1 g of the polycarbonate was dissolved in 100 ml and then filtered under pressure using a 0.22 μm filter.
Foreign matter on the filter was magnified and counted with a stereomicroscope at a magnification of 200 to 500 times.

Example 1 2,2-bis (4-hydroxyphenyl) propane 1
2.56 kg (55 mol), 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-
Tetraoxaspiro (5.5) undecane 16.74k
g (55 mol), 23.8 kg of diphenyl carbonate
(111 mol), sodium hydrogen carbonate 3.3 × 10 −4
Mol was charged into a 50 L raw material dissolving tank,
The mixture was heated to 0 ° C. and dissolved. 0.5 μm
It was transported under pressure to a 50 L reaction tank while passing through a pipe equipped with a filter, and 3.3 ml of a 0.1 mol / L aqueous sodium hydrogen carbonate solution filtered through a 0.45 μm filter was added. This molten material was heated to 180 ° C. in a nitrogen atmosphere and stirred for 30 minutes. Thereafter, the degree of decompression is set to 150 mmH.
g at the same time as 200 ° C at a rate of 60 ° C / hr.
Then, the temperature was raised to perform a transesterification reaction. Furthermore, the temperature was raised to 260 ° C. while distilling off phenol, and the temperature was maintained at that temperature for 10 minutes.
g or less. The reaction was carried out under stirring for a total of 6 hours, and after completion of the reaction, nitrogen was blown into the reactor to return to normal pressure. The polycarbonate produced was taken out by a gear pump while passing through a 20 μm filter provided at the lower part of the reactor, and the cylinder was fed to a kneader equipped with a vent heated to 250 ° C. N-butyl paratoluenesulfonate in the resin is 7
ppm, SH556 (manufactured by Toray Silicone Co., Ltd.) is 3000
ppm, ADK STAB AO-50 200 ppm, ADK STAB 2112 200 ppm, Tinuvin 32
These additive mixed solutions filtered through a 0.45 μm filter were fed simultaneously with the resin into a kneader so that 9 became 1000 ppm, and 30 μm placed at the outlet of the kneader.
The strand was pulled and pelletized while passing through an m filter. Table 1 shows the physical properties of the aromatic-aliphatic copolymerized polycarbonate.

Example 2 In Example 1, the total reaction time was 5 hours, the filter at the bottom of the reactor was 10 μm, and the cylinder temperature of the kneader was 2
The same operation as in Example 1 was performed except that the temperature of the filter set at 60 ° C. and the outlet of the kneader was changed to 10 μm. Table 1 shows the physical properties of the aromatic-aliphatic copolymerized polycarbonate.
Shown in

Example 3 In Example 1, the temperature of the resin was raised to 265 ° C., the filter at the lower part of the reactor was 10 μm, the cylinder temperature of the kneader was 265 ° C., and the filter installed at the outlet of the kneader was 20 μm.
Except having changed to, the same operation as in Example 1 was performed.
Table 1 shows the physical properties of the aromatic-aliphatic copolymerized polycarbonate.

Comparative Example 1 The same operation as in Example 1 was carried out except that the molten raw material was not filtered, no filter was provided at the lower part of the reactor, and no filter was provided at the kneader outlet. Table 1 shows the physical properties of the aromatic-aliphatic copolymerized polycarbonate.

[0040]

[Table 1]

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Kakuda 22nd Wadai, Tsukuba, Ibaraki Pref. Mitsubishi Gas Chemical Company, Ltd.

Claims (5)

[Claims] 1. The number of foreign substances having a size of 10 μm or more in 1 g of an aromatic-aliphatic copolymer polycarbonate comprising a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2) is 100: Pieces or less, size 1 μm or more and 10
An aromatic-aliphatic copolymer polycarbonate, wherein the number of foreign substances having a size of less than μm is 5000 or less, and the number of foreign substances having a size of 0.5 μm or more and less than 1 μm is 1 × 10 ⁵ or less. Embedded image (In the above formula (1), X is Wherein R ₃ and R ₄ are each a hydrogen atom,
An alkyl group having 1 to 10 carbon atoms or a phenyl group,
R ₃ and R ₄ may combine to form a ring. R ₁ and R ₂ are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or halogen, and R ₁ and R ₂ may be the same or different. Further, m and n represent the number of substituents and are integers of 0 to 4. ) (In the above formula (2), R ₅ , R ₆ , R ₇ and R ₈ are each a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.) 2. In a polymerization reactor, an aromatic dihydroxy compound represented by the following formula (3), an aliphatic dihydroxy compound represented by the following formula (4) and a carbonic acid diester are melted in the presence of a basic catalyst. The method for producing an aromatic-aliphatic copolymer polycarbonate according to claim 1, wherein in the method for producing a polycarbonate by condensation, at least one filter is provided before and / or after the polymerization reactor. Embedded image (In the above formula (3), X is Wherein R ₃ and R ₄ are each a hydrogen atom,
An alkyl group having 1 to 10 carbon atoms or a phenyl group,
R ₃ and R ₄ may combine to form a ring. R ₁ and R ₂ are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or halogen, respectively, and R ₁ and R ₂ may be the same or different. M and n represent the number of substituents and
4 is an integer. ) (In the above formula (4), R ₅ , R ₆ , R ₇ and R ₈ are each a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms.) 3. In a polymerization reactor, an aromatic dihydroxy compound represented by formula (3) according to claim 2 and a compound represented by formula (4)
In the method for producing a polycarbonate by melt-polycondensation of an aliphatic dihydroxy compound and a carbonic acid diester represented by the following, in the presence of a basic catalyst, kneading an additive, at least before and / or after the polymerization reactor Install one filter and at least one filter behind the additive kneader.
The method for producing an aromatic-aliphatic copolymer polycarbonate according to claim 1, wherein a base filter is provided. 4. The filter installed before the reactor has an absolute filtration accuracy of 0.5 μm to 2 μm, and the filter installed behind the reactor has an absolute filtration accuracy of 2 μm to 3 μm.
The method for producing an aromatic-aliphatic copolymer polycarbonate according to claim 2 or 3, wherein the absolute filtration accuracy of a filter provided behind the additive kneader is 2 µm or more and 50 µm or less. 5. An impact-resistant plastic lens comprising the aromatic-aliphatic copolycarbonate according to claim 1.