JPH11349678A - Preparation of aromatic-aliphatic copolymerized polycarbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject resin exhibiting excellent resistance to impact and to heat and having not only a high Abbe number and a low photoelastic constant but also an excellent color tone by polycondensating an aromatic dihydroxy compound and an aliphatic dihydroxy compound having an iron content of not more than a specific value with a carbonic acid diester in a molten state under heat. SOLUTION: An aromatic dihydroxy compound represented by formula I, an aliphatic dihydroxy compound represented by formula II and a carbonic acid diester are subjected to the polycondensation in a molten state under heat, the iron content in the aliphatic dihydroxy compound being restricted to not more than 1 ppm. In formula I, X is represented by formula III; R3 and R4 are each H, a 1-10C alkyl or phenyl and can be bonded together to form a ring; R1 and R2 are the same or different and are each H, a 1-10C alkyl or a halogen; and (m) and (n) are each an integer of 0-4. In formula II, R5 , R6 , R7 and R8 are each H or 1-10C monovalent alkyl.

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 the drawbacks of such bisphenol A-polycarbonate, the present inventors have previously described aromatic-
Aliphatic copolymer polycarbonate resin (Japanese Patent Application No. 8-276)
260). This aromatic-aliphatic copolymerized polycarbonate resin 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. 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. In order to solve this problem, Japanese Patent Application Laid-Open No. Hei 6-179744 proposes to improve the coloring by using a material having a low iron content or a material containing no iron as the material of the reactor.

[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 Wherein R ₃ and R ₄ are each a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a phenyl group, and R ₃ and R ₄
May combine with each other 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. Also,
m and n represent the number of substituents and are integers from 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 a monovalent alkyl group having 1 to 10 carbon atoms.)

The inventors of the present invention have made intensive studies to achieve the above object, and found that there is a correlation between the color tone of the aromatic-aliphatic copolymerized polycarbonate and the iron concentration contained in the aliphatic dihydroxy compound used. The present inventors have found that there is a relationship, and have found that a resin having a good color tone can be obtained by using an aliphatic dihydroxy compound having an iron content of not more than a specific value, thereby completing the present invention.

That is, according to the present invention, an aromatic dihydroxy compound represented by the formula (1), an aliphatic dihydroxy compound represented by the formula (2), and a carbonic acid diester are subjected to polycondensation under heating and melting to obtain an aromatic compound. When producing an aliphatic copolymerized polycarbonate, an aromatic-aliphatic polycarbonate characterized by using an aliphatic dihydroxy compound having an iron content of 1 ppm or less, preferably 0.5 ppm or less, more preferably 0.2 ppm or less. It is a manufacturing method.

[0008]

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). , 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, as the aliphatic dihydroxy compound, a compound having an iron content of 1 ppm or less is used.

The aliphatic dihydroxy compound represented by the above formula (1) is generally produced from an aldehyde represented by the following reaction formula (3) and pentaerythritol by a known acetalization reaction. Here, any strong acid can be used as a catalyst, and sulfuric acid and p-toluenesulfonic acid are preferably used.

Embedded image (Where R ₅ , R ₆ , R ₇ , and R ₈ are a hydrogen atom or a
It is a 10 monovalent alkyl group. The aldehyde in the above formula is easily synthesized from the corresponding aldehyde and formaldehyde by a known method by the reaction of the following reaction formula (4). )

Embedded image (In the above reaction formula (4), R ₅ and R ₆ are a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms.
A hydroxyaldehyde in which the substituents R ₅ and R ₆ are replaced with R ₇ and R ₈ can be synthesized in the same manner. )

As the raw materials and auxiliary raw materials used in these reactions, those which do not substantially contain iron are used, and iron is not contaminated from kettles and pipes during the process. An aliphatic dihydroxy compound having an iron content of 1 ppm or less can be obtained.

However, in the case of the above-mentioned commercially available dihydroxy compound, a considerable amount of iron may be contained as an impurity. The present inventors have conducted intensive studies on a method of reducing the iron content in a commercially available product, and after heating and dissolving the aliphatic dihydroxy compound in a solvent, performing hot filtration using a filter having an appropriate pore size. Thereafter, it was found that the aliphatic dihydroxy compound obtained by cooling and recrystallizing the solution did not substantially contain iron.

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 characteristics 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 solvent 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 the 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.

The crude aliphatic dihydroxy compound represented by the above formula (2) is dissolved by heating in a solvent, and then filtered while hot through a filter. The filter pore size is preferably 1 μm or less,
More preferably, it is 0.5 μm or less, more preferably 0.1 μm or less. With a filter having a filter pore size of 1 μm or more, fine foreign matters containing iron cannot be sufficiently removed, and the desired iron content cannot be achieved. As a material of the filter, a material that does not dissolve or swell in a heating solvent is preferable.Acetate, polyether sulfone, polytetrafluoroethylene, nylon, a polyester nonwoven fabric coated with cellulose acetate, polypropylene, filter paper,
It can be appropriately selected from glass fiber filter paper, stainless steel, sintered metal and the like. Several filters can be connected in series in ascending order of pore size. For filtration, either reduced pressure or increased pressure may be used. The hot filtration temperature is set slightly higher than the crystal deposition temperature so that crystals do not precipitate during filtration and clogging of the filter does not occur.

Crystals of the aliphatic dihydroxy compound are precipitated from the hot filtration solution by a cooling operation. The obtained crystals are separated from the solution and the crystals by filtration, and the crystals are rinsed with a solvent if necessary, and the solvent is removed by drying, whereby an aliphatic dihydroxy compound having a low iron content can be obtained. Further, if necessary, a higher purity aliphatic dihydroxy compound can be obtained by performing recrystallization twice or more.

The present invention does not prevent the step of contacting with the adsorbent during the recrystallization step. 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 filtration with the above-mentioned filter, 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 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 is a random, block, alternating copolymer or Since it contains a blend of a structural unit derived from the aromatic dihydroxy compound represented by the above formula (1) and a polycarbonate composed of a structural unit derived from the aliphatic dihydroxy compound represented by the above formula (2), and the like. , Excellent heat resistance and hue, as well as well-balanced refractive index and dispersion properties, and low birefringence.

In the present invention, a structural unit derived from an aromatic dihydroxy compound (hereinafter, referred to as I);
The molar ratio (I / II) of the structural unit (hereinafter, referred to as II) derived from the aliphatic dihydroxy compound is 90 /
It is preferably 10 to 10/90, and more preferably 80/20 to 20/80. That is, the aromatic dihydroxy compound (1) in the polycarbonate
When the molar ratio (I / II) of the structural unit derived from the aliphatic dihydroxy compound (2) is lower than 10/90, the heat resistance is inferior. When the molar ratio is higher than 90/10, the photoelastic constant, water absorption, etc. And the balance between the refractive index and the Abbe number becomes poor, which is not preferable as an optical material.

In the present invention, 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 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 polycarbonate resin used in the present invention preferably has a weight average molecular weight of 30,000 to 200,000, more preferably 50,000 to 1,000,000.
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.

Specific examples of the nitrogen-containing compound include alkyl, aryl, such as tetramethylammonium 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 ^-1 mol, per 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 under a reduced pressure of 1 mmHg or less at a temperature of 200 to 300 ° C. 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 hydrolysis stability, it is preferable to remove or deactivate the catalyst from 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 a 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.

[0045]

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.

[0047]

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

The iron was quantified by ICP emission spectrometry after a predetermined amount of the aliphatic dihydroxy compound was wet-ashed (sulfuric acid and nitric acid) by an automatic wet-ashing apparatus.

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)
After completely dissolving 800 g in 10 liters of methanol at a temperature of 60 ° C., the solution was filtered while hot through a PTFE membrane filter (TCF010 manufactured by Advantech) having a pore size of 0.1 μm. The obtained solution was cooled to room temperature to obtain spiroglycol crystals. The crystals were separated by filtration, rinsed with approximately the same volume of methanol as the crystals, and then dried in a vacuum drier.
The crystals were dried at ℃ to obtain 560 g of crystals. The iron content in the obtained spiroglycol was 0.2 ppm. 2,2.8 g of 2,2-bis (4-hydroxyphenyl) propane
(0.10 mol), purified spiroglycol 3 obtained above
0.4 g (0.10 mol), diphenyl carbonate 4
3.3 g (0.202 mol), sodium bicarbonate 6.
0 × 10 −7 moles is 300 with stirrer and distilling device
The flask was placed in a four-neck flask, heated to 180 ° C. under a nitrogen atmosphere, and stirred for 30 minutes. Thereafter, the degree of decompression was set to 150 mm
Hg and at the same time, 200 ° C at a rate of 60 ° C / hr.
The temperature was raised to ° C., and a transesterification reaction was performed. further,
The temperature was raised to 260 ° C. while distilling off phenol, and the temperature was maintained at that temperature for 10 minutes.
Hg or less. 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 2 800 g of a commercially available spiroglycol was completely dissolved in 10 liters of methanol at a temperature of 60 ° C.
5 μm polyester nonwoven fabric coated with cellulose acetate (Advantech TC
(YE-HS). The resulting solution was cooled to room temperature to obtain spiroglycol crystals. The crystals were separated from the solution using a Nutsche, rinsed with approximately the same volume of methanol as the crystals, and dried at 60 ° C. using a vacuum drier to obtain 560 g of spiroglycol. The iron content in the obtained spiroglycol was 0.5 ppm. 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 3 800 g of commercially available spiroglycol was dissolved in 10 liters of 2-ethoxyethanol at 90 ° C.
Hot filtration was performed through a μm SUS316L filter (manufactured by TSFS Japan). The resulting solution was cooled to room temperature to obtain spiroglycol crystals. The resulting solution was cooled to room temperature to obtain spiroglycol crystals. The crystals were separated from the solution using Nutsche, and 2-
After rinsing with ethoxyethanol, the product was dried at 60 ° C. using a vacuum drier to obtain 720 g of spiroglycol. The iron content in the obtained spiroglycol was 0.30.
ppm. 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. The iron content in the obtained spiroglycol was 0.3
It was 0 ppm. 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 same operation as in Example 1 was performed, except that commercially available spiroglycol having an iron content of 2.1 ppm was used as it was. The obtained polycarbonate had a very poor color tone.

Comparative Example 2 800 g of a commercially available spiroglycol was dissolved in 10 liters of methanol at 60 ° C., and then a cotton wind cartridge filter having a pore size of 1 μm (Advantech T
Hot filtration was performed through CW-1). The resulting solution was cooled to room temperature to obtain spiroglycol crystals. The crystals were separated from the solvent using a Nutsche, rinsed with approximately the same volume of methanol as the crystals, and dried at 60 ° C. using a vacuum drier to obtain 560 g of spiroglycol. The iron content in the obtained spiroglycol was 1.4 ppm. Except that this 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.

The physical properties shown in Table 1 are 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).

[0057]

[Table 1]

[0058]

[Table 2]

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takayasu Fujimori 22nd Wadai, Tsukuba, Ibaraki Pref.

Claims (4)

[Claims] 1. An aromatic-aliphatic copolymer obtained by polycondensing 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. In the method for producing a polycarbonate, the iron content in the aliphatic dihydroxy compound is 1 pp.
m or less, and a method for producing an aromatic-aliphatic copolymerized polycarbonate. 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, and R ₃ and R ₄
May combine with each other 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. Also,
m and n represent the number of substituents and are integers from 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 aroma according to claim 1, wherein the aliphatic dihydroxy compound is obtained by heating and dissolving the crude aliphatic dihydroxy compound in a solvent, followed by hot filtration and recrystallization from the filtrate. For producing an aliphatic-aliphatic copolymerized polycarbonate. 4. The process 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.