JP2000007777A - Preparation of aromatic-aliphatic copolymer polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin having an excellent impact resistance, an excellent heat resistance, a high Abbe number, a low photoelasticity constant and an excellent color tone by polycondensing the mixture of an aromatic dihydroxy compound, an aliphatic dihydroxy compound and a diester carbonate continuously in a horizontal reaction vessel having specific mixing blades and in a horizontal mixing polymerization vessel. SOLUTION: An aromatic dihydroxy compound of formula I, an aliphatic dihydroxy compound of formula II and a diester carbonate are used. A polymer having a weight average molecular weight of 30,000-60,000 is obtained by polycondensing a melt of the monomer mixture in at least one horizontal mixing polymerization vessel having a vertical rotation axis with mixing blades and then a polycarbonate having a weight average molecular weight of not less than 70,000 is obtained by carrying out the polycondensation further in at least one horizontal polymerization vessel having a horizontal rotation axis with mixing blades which are mutually discontinuous and have L/D of 1-15. In the formulas, X is formula III or IV; R1 and R2 are each hydrogen, a 1-10C alkyl group or a halogen; m and n are each 0-4; and R3 and R4 may bond each other to form a ring; R5 to R8 are each hydrogen or a monovalent 1-10C alkyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing an aromatic-aliphatic polycarbonate having excellent impact resistance, low photoelastic constant, high refractive index and inverse dispersion value, and excellent transparency and heat resistance. More specifically, the present invention relates to a method for producing an aromatic-aliphatic copolymer polycarbonate having a good color tone.

[0002]

2. Description of the Related Art A polycarbonate resin obtained by interfacially polymerizing an aromatic dihydroxy compound such as bisphenol A and phosgene in the presence of an acid binder has excellent mechanical properties such as impact resistance, heat resistance, and transparency. Because of its excellent properties, it is used as an optical material for various lenses, prisms, optical disk substrates, and the like. However, a polycarbonate using only bisphenol A as an aromatic dihydroxy compound has a large photoelastic constant,
Since the melt fluidity is relatively poor, the birefringence of the molded product becomes large, and the Abbe number is 3 although the refractive index is as high as 1.58.
Since it is as low as 0, it has 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 described aromatic-aliphatic copolymerized polycarbonate resin (Japanese Patent Application No. Hei 8-27).
6260). This aromatic-aliphatic copolymer polycarbonate resin has excellent impact resistance and heat resistance,
In addition, since the photoelastic constant is small and the Abbe number is high,
It can be widely used as an optical material. Such an aromatic-aliphatic copolycarbonate 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 diphenyl carbonate and the like. A method in which polycondensation with a carbonic acid diester in a molten state by a transesterification reaction is suitably used.

[0003] In the transesterification reaction, when producing polycarbonate, polycondensation is usually carried out while heating to a temperature of 200 ° C to 330 ° C. However, it is difficult to obtain an excellent product. For this reason, it has been difficult to use the polycarbonate obtained by this method in a field requiring a color tone.

[0004]

SUMMARY OF THE INVENTION The present invention aims to solve the problems associated with the prior art as described above, and provides excellent impact resistance, heat resistance, high Abbe number and low photoelastic constant. It is an object of the present invention to provide a method for producing an aromatic-aliphatic polycarbonate resin having excellent color tone.

[0005]

Means for Solving the Problems The polycarbonate resin of the present invention comprises a structural unit derived from an aromatic dihydroxy compound represented by the following formula (1) and an aliphatic dihydroxy compound represented by the following formula (2). It is characterized by comprising a derived unit and a derived unit derived from carbonic acid diester.

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

Embedded image , And the here, R ₃ and R ₄ are each a hydrogen atom, an alkyl group or a phenyl group having 1 to 10 carbon atoms, and R ₃
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. 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 a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms.)

The inventors of the present invention have conducted intensive studies to achieve the above object. As a result, the color tone of the above-mentioned aromatic-aliphatic copolymerized polycarbonate and the molten Hazen color of the aliphatic dihydroxy compound to be used after being held at a specific temperature for a specific period of time. And found that a resin having a good color tone can be obtained by using an aliphatic dihydroxy compound having a molten Hazen color number equal to or less than a specific value, thereby completing the present invention. Was.

That is, the present invention provides an aromatic dihydroxy compound represented by the above formula (1), an aliphatic dihydroxy compound represented by the above formula (2), and a carbonic acid diester by polycondensation under heating and melting. When producing an aliphatic-aliphatic copolymerized polycarbonate, an aliphatic dihydroxy compound having a molten Hazen color number of 40 or less, preferably 20 or less, more preferably 15 or less after holding at 260 ° C. for 5 hours in the air is used. This is a method for producing an aromatic-aliphatic polycarbonate, which is characterized in that it is used.

In the present invention, the melting Hazen color number is J
It is measured by the method described in IS K-4101, and is measured by the melting Hazen color number after the aliphatic dihydroxy compound is completely melted at a specific temperature and held for a specific time after the solution has reached a specific temperature.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing an aromatic-aliphatic polycarbonate according to the present invention will be specifically described.

The polycarbonate according to the present invention comprises a structural unit derived from an aromatic dihydroxy compound represented by the above formula (1) and a structural unit derived from an aliphatic dihydroxy compound represented by the above formula (2) And a structural unit derived from carbonic acid diester.

As the aromatic dihydroxy compound, 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-hydroxy Phenyl) 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'-dihydroxydiphenyl sulfoxide, , 4'-dihydroxy-3,3-dimethyldiphenylsulfoxide, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxy-3,
3'-dimethyldiphenyl sulfone or the like is used.

Of these, in particular, 2,2-bis (4-
Hydroxyphenyl) propane, bisphenol A, or 1,1-bis (4-hydroxyphenyl) cyclohexane is preferred.

As the aliphatic dihydroxy compound, 3,
9-bis (2-hydroxyethyl-2,4,8,10-
Tetraoxaspiro (5.5) 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 are used. Preferably, 3,9-bis (2-hydroxy-1,
1-dimethylethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane is used.

The present invention is characterized in that the aliphatic dihydroxy compound used is purified so that the molten Hazen color number after holding at 260 ° C. for 5 hours in the atmosphere becomes No. 40 or less.

In order to produce such an aliphatic dihydroxy compound that gives a molten Hazen color number equal to or less than a specific value, a purification method such as distillation and recrystallization can be used effectively. A method of heating and dissolving the group dihydroxy compound in a solvent and then cooling it to recrystallize is particularly effective. In this case, it is more effective to include a step of removing a coloring agent by adsorption.

As the recrystallization solvent that can be used in the present invention, it is preferable that the solubility of the aliphatic dihydroxy compound is sufficiently high at a high temperature and sufficiently low at around room temperature. It is more preferable that the coloring component of the resin is removed by the operation. Examples of the solvent having such properties include alcohols, ethers, esters, ketones, and aromatic hydrocarbons.

More specifically, examples of the compound include alcoholic solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-butanol, tert-butanol and 1-butanol.
Pentanol, 2-methyl-1-butanol, isoamyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, caprylic alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, allyl alcohol, crotyl alcohol, propargyl alcohol, Cyclopentanol, cyclohexanol, 2-methoxyethanol, 2
-Ethoxyethanol, 2-butoxyethanol, ethylene glycol and the like.

Examples of ether solvents include diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diisobutyl ether, di-n-amyl ether, diisoamyl ether, methyl butyl ether, methyl-n-amyl ether, methyl isoamyl ether, Ethyl propyl ether, ethyl isopropyl ether, ethyl butyl ether, ethyl isobutyl ether, ethyl-n-amyl ether, ethyl isoamyl ether, diallyl ether, ethyl allyl ether, anisole, phenetole, diphenyl ether,
Examples thereof include dibenzyl ether, tetrahydrofuran, 1,4-dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether.

Examples of the ester solvents include ethyl acetate, isobutyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, and butyl propionate. Isobutyl propionate, n-amyl propionate, isoamyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, n-butyrate
Amyl, isoamyl butyrate, methyl isobutyrate, ethyl isobutyrate, propyl isobutyrate, isopropyl isobutyrate, isobutyl isobutyrate, isoamyl isobutyrate, methyl valerate,
Ethyl valerate, propyl valerate, butyl valerate, n-amyl valerate, isoamyl valerate, methyl isovalerate, ethyl isovalerate, propyl isovalerate, isopropyl isovalerate, isobutyl isovalerate, isovaleric acid Isoamyl, methyl benzoate, ethyl benzoate and the like can be mentioned.

Examples of ketone solvents include acetone, methyl ethyl ketone, isopropyl methyl ketone, butyl methyl ketone, isobutyl methyl ketone, pinacolone, diethyl ketone, butyrone, diisopropyl ketone, methyl vinyl ketone, mesityl oxide, methyl heptenone,
Examples thereof include cyclobutanone and cyclohexanone.

Examples of the aromatic hydrocarbon compound include benzene, toluene, xylene, mesitylene and the like.

Of these, particularly preferred recrystallization solvents are alcohols, and more preferred are alcohols having 1 to 10 carbon atoms. Further, two or more of the above solvents may be used as a mixture.

Recrystallization can be carried out by a known method, and recrystallization may be carried out two or more times depending on the purity of the raw material and the like. The crystals obtained by recrystallization are filtered, washed, dried by an appropriate method, and used as a resin raw material.

By including a step of contacting with an adsorbent during the recrystallization step, the number of molten Hazen colors can be further improved. That is, the aliphatic dihydroxy compound is dissolved in a solvent and then brought into contact with the adsorbent. As a method thereof, a batch method in which an adsorbent is added to a solution and stirring is performed, and a flow method in which the solution is passed through an adsorbent layer packed in a column are suitably performed.

As the adsorbent, activated carbon, alumina, silica, zeolite and the like are preferably used, and activated carbon is particularly preferred.

After the adsorbent is completely removed from the solution subjected to the adsorption treatment by a method such as filtration, crystals of the aliphatic dihydroxy compound are obtained by the above-mentioned ordinary recrystallization.

The polycarbonate resin according to the present invention comprises:
It comprises a structural unit derived from the aromatic dihydroxy compound represented by the above formula (1) and a structural unit derived from the aliphatic dihydroxy compound represented by the above formula (2), and is random, block, or alternating. A copolymer or a polycarbonate comprising a structural unit derived from an aromatic dihydroxy compound represented by the above formula (1);
Since it contains a blend of a polycarbonate comprising a structural unit derived from the aliphatic dihydroxy compound represented by the above formula (2), it has excellent heat resistance, hue, and balanced refractive index and dispersion characteristics. And a characteristic that the birefringence is low.

In the present invention, a structural unit derived from an aromatic dihydroxy compound (hereinafter referred to as I) and a structural unit derived from an aliphatic dihydroxy compound (hereinafter referred to as I)
I) is 90/10 to 1
0/90, preferably 80/90.
/ 20 to 20/80 are preferred. That is, the molar ratio of the structural units derived from the aromatic dihydroxy compound and the aliphatic dihydroxy compound in the polycarbonate (I / I
When I) is lower than 10/90, the heat resistance becomes poor,
If it is higher than 90/10, the photoelastic constant, the water absorption and the like will be high, and the balance between the refractive index and the Abbe number will be poor, which is not preferable as an optical material.

In the present invention, as the carbonic acid diester, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate and the like are used. . 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 polycarbonate resin used in the present invention is preferably 30,000 to 200,000, more preferably 50,000 to 1
20,000.

In the method for producing a polycarbonate according to the present invention, a basic compound is used as a catalyst. Examples of such a basic compound include an alkali metal and / or alkaline earth compound, a nitrogen-containing compound, and the like.

Examples of such compounds include organic acids such as alkali metals and alkaline earth compounds, inorganic salts, oxides, hydroxides, hydrides or alkoxides, quaternary ammonium hydroxides and salts thereof, amines and the like. Are preferably used, and these compounds can be used alone or in combination.

As such an alkali metal compound,
Specifically, sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, sodium hydrogen carbonate, 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, sodium borohydride, sodium benzoate, potassium benzoate, cesium benzoate, lithium benzoate, disodium hydrogen phosphate , Dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium phenylphosphate, disodium salt of bisphenol A, 2 potassium salt, 2 cesium salt, 2 lithium salt, phenol sodium salt, potassium salt, cesium salt, lithium Salts and the like are used.

Further, as the alkaline earth metal compound,
Specifically, magnesium hydroxide, calcium hydroxide,
Strontium hydroxide, barium hydroxide, magnesium bicarbonate, calcium bicarbonate, strontium bicarbonate, barium bicarbonate, magnesium acetate, calcium acetate, strontium acetate, barium acetate, magnesium stearate, calcium stearate, calcium benzoate, phenyl phosphate Magnesium or the like is used.

Examples of the nitrogen-containing compound include alkyl, aryl, tetraalkylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide and trimethylbenzylammonium hydroxide. Ammonium hydroxides having an araryl group and the like, tertiary amines such as triethylamine, dimethylbenzylamine and triphenylamine, secondary amines such as diethylamine and dibutylamine, primary amines such as propylamine and butylamine,
Imidazoles such as 2-methylimidazole and 2-phenylimidazole, or basic salts such as ammonia, tetramethylammonium borohydride, tetrabutylammonium tetraphenylborate, and tetraphenylammonium tetraphenylborate are used.

These catalysts are used in an amount of 10 ^-9 to 10 ^-3 mol, preferably 10 ^-7 to 1 based on 1 mol of the total of the aromatic dihydroxy compound and the aliphatic dihydroxy compound.
Used in an amount of 0 ^-5 mol.

The transesterification according to the present invention can be carried out by a known melt polycondensation method. That is, melt polycondensation is carried out using the above-mentioned raw materials and a catalyst while removing by-products by transesterification under heating or normal pressure or reduced pressure. The reaction is generally carried out in two or more stages.

Specifically, the first-stage reaction is carried out at 120 to 2
The reaction is carried out at a temperature of 60 ° C, preferably 180 to 240 ° C, for 0 to 5 hours, preferably 0.5 to 3 hours. Next, the reaction temperature is increased while increasing the degree of vacuum of the reaction system, and the reaction of the aromatic dihydroxy compound, the aliphatic dihydroxy compound and the carbonic acid diester is carried out. Finally, the reaction is carried out at a temperature of 200 to 300 ° C. under a reduced pressure of 1 mmHg or less. Perform a condensation reaction. Such a reaction may be carried out continuously or batchwise. The reaction apparatus used for performing the above reaction may be a tank type or an extruder type.

In order to maintain heat stability and hydrolytic stability, it is preferable to remove or deactivate the catalyst of the polycarbonate obtained at the end of the polymerization of the present invention. The method of deactivating a transesterification catalyst such as an alkali metal or an alkaline earth metal by the above method is preferably carried out. As these substances, specifically, aromatic sulfonic acids such as p-toluenesulfonic acid, butyl p-toluenesulfonate, aromatic sulfonic acid esters such as hexyl p-toluenesulfonic acid,
Organic halides such as stearic acid chloride, butyric acid chloride, benzoyl chloride, p-toluenesulfonic acid chloride, alkyl sulfates such as dimethyl sulfate, organic halides such as benzyl chloride, and inorganic acids such as boric acid and phosphoric acid are preferable. Used for

After deactivation of the catalyst, a step of degassing and removing low boiling compounds in the polymer at a pressure of 0.1 to 1 mmHg and a temperature of 200 to 300 ° C. may be provided. A horizontal apparatus equipped with a stirring blade having excellent surface renewability, such as a wing or an eyeglass wing, or a thin film evaporator is suitably used.

Further, in the present invention, the above-mentioned heat stabilizer,
In addition to hydrolysis stabilizers, antioxidants, pigments, dyes, reinforcing agents and fillers, ultraviolet absorbers, lubricants, release agents, crystal nucleating agents, plasticizers, flow improvers, antistatic agents, etc. Can be added.

Each of these additives can be mixed with the polycarbonate resin by a conventionally known method. For example, a method in which each component is dispersed and mixed by a high-speed mixer represented by a turnbull mixer, a Henschel mixer, a ribbon blender, or a super mixer, and then melt-kneaded by an extruder, a Banbury mixer, a roll, or the like is appropriately selected.

[0043]

The polycarbonate resin of the present invention has improved refractive index, dispersion balance and photoelastic constant while maintaining the excellent properties of polycarbonate such as impact resistance and heat resistance. , Prisms, optical disc substrates, and other plastic optical materials.

Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples.

[0045]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

Example 1 Commercially available 3,3'-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane (hereinafter referred to as spiroglycol)
800 g was completely dissolved in 10 liters of methanol at a temperature of 60 ° C., and then cooled to room temperature to recrystallize spiroglycol. The crystals were separated by filtration, rinsed with approximately the same volume of methanol as the crystals, and then dried at 60 ° C. in a vacuum drier to obtain 560 g of crystals. The melted Hazen color number of the crystal after holding at 260 ° C. for 5 hours in the atmosphere was 35. 2,2-
Bis (4-hydroxyphenyl) propane 22.8 g
(0.10 mol) and the above purified spiroglycol 30.4
g (0.10 mol) and 43.3 of diphenyl carbonate
g (0.202 mol) with sodium bicarbonate 6.0 ×
10 ^-7 mol was placed in a 300 cc four-necked flask equipped with a stirrer and a distilling apparatus, and heated to 180 ° C. under a nitrogen atmosphere.
Stir for 30 minutes. Thereafter, the degree of pressure reduction was adjusted to 150 mmHg, and at the same time, the temperature was raised to 200 ° C. at a rate of 60 ° C./hr to perform a transesterification reaction. Further, the temperature was raised to 260 ° C. while distilling off phenol, and the temperature was maintained at that temperature for 10 minutes, and the degree of reduced pressure was reduced to 1 mmHg or less over 1 hour. The reaction was carried out under stirring for a total of 6 hours. After the reaction was completed, nitrogen was blown into the reactor to return to normal pressure, and the produced polycarbonate was taken out. Table 1 shows the physical properties of this polycarbonate.

Example 2 As a solvent for recrystallization of spiroglycol, isobutanol was used in place of methanol, and spiroglycol 800 was used.
g was completely dissolved in 10 L of isobutanol at 90 ° C., then cooled to room temperature and recrystallized. After the crystals were separated by filtration, the crystals were washed with approximately the same volume of isobutanol as the crystals.
And dried under vacuum to obtain 700 g of spiroglycol crystals. 260 ° C., 5
The melted Hazen color number after holding for a time was 35. Except that this purified spiro glycol was used, the same operation as in Example 1 was performed to obtain a bisphenol A-spiro glycol copolymerized polycarbonate. Table 1 shows the physical properties of the obtained polycarbonate.

Example 3 Using 2-ethoxyethanol instead of methanol as a solvent for recrystallizing spiroglycol, 800 g of spiroglycol was completely dissolved in 10 liters of 2-ethoxyethanol at 90 ° C., and then cooled to room temperature. Recrystallization was performed. After the crystals were separated by filtration, the crystals were washed with 2-ethoxyethanol having almost the same volume as the crystals, and dried at 80 ° C. under vacuum to obtain 720 g of spiroglycol crystals. The melted Hazen color number of the obtained spiroglycol after holding at 260 ° C. for 5 hours in the atmosphere was 30. Except that this purified spiro glycol was used, the same operation as in Example 1 was performed to obtain a bisphenol A-spiro glycol copolymerized polycarbonate. Table 1 shows the physical properties of the obtained polycarbonate.

Example 4 800 g of spiroglycol was added to 2-ethoxyethanol 1
A solution completely dissolved in 0 liter at 90 ° C.
After passing through a commercially available activated carbon cartridge filter (TCC-W1 manufactured by Advantech Toyo Co., Ltd.), the mixture was cooled to room temperature to recrystallize spiroglycol. After filtering off the crystals, the cake was rinsed with approximately the same volume of 2-ethoxyethanol, and dried at 80 ° C. with a vacuum drier to obtain 720 g of crystals. 260 ° C. in the atmosphere of the obtained spiroglycol,
The melted Hazen color number after holding for 5 hours was 15. Except that this purified spiro glycol was used, the same operation as in Example 1 was performed to obtain a bisphenol A-spiro glycol copolymerized polycarbonate. Table 1 shows the physical properties of the obtained polycarbonate.

Comparative Example 1 The procedure of Example 1 was repeated, except that commercially available spiroglycol was used without purification. The melted Hazen color number of the spiroglycol after holding at 260 ° C. for 5 hours in the atmosphere was 150. The obtained polycarbonate had a very poor color tone.

Comparative Example 2 Using 2-ethoxyethyl acetate instead of methanol as a recrystallization solvent for spiroglycol, 800 g of spiroglycol was completely dissolved in 10 L of 2-ethoxyethylacetate at 90 ° C., and then cooled to room temperature. Then, recrystallization was performed. After the crystals were separated by filtration, the crystals were washed with 2-ethoxyethyl acetate having substantially the same volume as the crystals, and dried at 80 ° C. under vacuum to obtain 700 g of spiroglycol crystals. The melted Hazen color number of the obtained spiroglycol after holding at 260 ° C. for 5 hours in the atmosphere was 50. Except that this purified spiro glycol was used, the same operation as in Example 1 was performed to obtain a bisphenol A-spiro glycol copolymerized polycarbonate. Table 1 shows the physical properties of the obtained polycarbonate, which was colored pale yellow.

Comparative Example 3 As a solvent for recrystallization of spiroglycol, diacetone alcohol was used in place of methanol, and 800 g of spiroglycol was completely dissolved in 10 liters of diacetone alcohol at 90 ° C., and then cooled to room temperature and recrystallized. Was done.
After the crystals were separated by filtration, the crystals were washed with diacetone alcohol having substantially the same volume as the crystals, and dried at 80 ° C. under vacuum to obtain 700 g of spiroglycol crystals. The melted Hazen color number of the obtained spiroglycol after holding at 260 ° C. for 5 hours in the atmosphere was 60. Except that this purified spiro glycol was used, the same operation as in Example 1 was performed to obtain a bisphenol A-spiro glycol copolymerized polycarbonate.
The physical properties of the obtained polycarbonate are shown in Table 1, and were colored yellow.

The physical properties in Table 1 were measured by the following methods.

(1) Molecular weight: GPC (Shodex G
It was measured as a polystyrene-equivalent molecular weight (weight average molecular weight: Mw) using PC system 11). Chloroform was used as a developing solvent. (2) Resin YI: The obtained resin was press-molded into a disc having a thickness of 40 mmφ and a thickness of 3 mm, and a color difference meter (Tokyo Denshoku TC-18)
00MK2) to measure the YI value (yellowness).

[0055]

[Table 1]

[0056]

[Table 2]

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takayasu Fujimori 22nd Wadai, Tsukuba-shi, Ibaraki F-term in Mitsubishi Gas Chemical Company, R & D Co., Ltd. (reference) BF30 BG08X BH02 BH07 HA01 HC04A HC05A KA01 KA03 KE05

Claims (6)

[Claims] 1. An aromatic-aliphatic polycondensation of an aromatic dihydroxy compound represented by the following formula (1), an aliphatic dihydroxy compound represented by the following formula (2), and a carbonic acid diester under heating and melting: A method for producing an aromatic-aliphatic copolymer polycarbonate, which comprises using an aliphatic dihydroxy compound having a molten Hazen color number of 40 or less after holding at 260 ° C. for 5 hours in the atmosphere. Embedded image (In the above formula (1), X is Wherein R ₃ and R ₄ are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a phenyl group, respectively, and R ₃ and R ₄ may combine to form a ring. R ₁ and R ₂ is a hydrogen atom, an alkyl group or a halogen having 1 to 10 carbon atoms, R ₁
And R ₂ may be the same or different. Also, m and n
Represents the number of substituents and is an integer of 0 to 4. ) (In the above formula (2), 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.) 2. The method according to claim 1, wherein the aliphatic dihydroxy compound is 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,
The method for producing an aromatic-aliphatic copolymer polycarbonate according to claim 1, which is 4,8,10-tetraoxaspiro (5.5) undecane. 3. The process for producing an aromatic-aliphatic copolymer polycarbonate according to claim 1, wherein the aliphatic dihydroxy compound is obtained by refining a crude aliphatic dihydroxy compound by recrystallization. 4. The method for producing an aromatic-aliphatic copolymer polycarbonate according to claim 3, wherein the solvent used for recrystallization is an alcohol having 1 to 10 carbon atoms. 5. The method for producing an aromatic-aliphatic copolymerized polycarbonate according to claim 3, further comprising the step of contacting with an adsorbent during the recrystallization operation. 6. The method for producing an aromatic-aliphatic copolymer polycarbonate according to claim 5, wherein the adsorbent is activated carbon.