JP2010132782A - Polycarbonate copolymer, method for producing the same and use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polycarbonate copolymer exhibiting a high moldability, a high refractive index and a low birefringence. <P>SOLUTION: The polycarbonate copolymer comprises (A) a structural unit represented by formula (1) and (B) a structural unit represented by formula (2) in the molar ratio of (A):(B) of 99:1-60:40. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polycarbonate copolymer having a specific structure and a method for producing the same. The present invention also relates to the use of the polycarbonate copolymer.

  Polycarbonate resin obtained by reacting 2,2-bis (4-hydroxyphenyl) propane (common name: bisphenol A) with phosgene or carbonic acid diester is excellent in heat resistance and transparency, and has mechanical properties such as impact resistance. Therefore, it is widely used as an optical material for plastic optical products and optical films such as various lenses, prisms, optical disk substrates, and optical fibers as well as structural materials.

  However, since the conventional aromatic polycarbonate resin is a low fluidity material exhibiting a high photoelastic modulus, there is a problem that the birefringence accompanying the molecular orientation and residual stress during molding is large. Therefore, conventionally, when optical products are produced from aromatic polycarbonate resins, in order to reduce birefringence, a resin having a relatively low molecular weight is used to improve fluidity, and molding is often performed at a high temperature. ing. However, even if this method is used, there is a limit in reducing birefringence when a conventional aromatic polycarbonate resin is used. With the spread of optical material applications in recent years, there is a strong demand for the development of highly fluid materials that exhibit a lower photoelastic coefficient in some optical material fields.

  On the other hand, when an optical material with a high refractive index is used, the lens element can be realized with a surface with a smaller curvature, so that the amount of aberration generated on this surface can be reduced, the number of lenses can be reduced, the lens eccentricity sensitivity can be reduced, and the lens thickness. By reducing this, the lens system can be reduced in size and weight. In addition, when an optical material having a high refractive index is used, the spectacle lens having the same power can be made thinner, and there is an advantage that the appearance is remarkably improved. No commercially available thermoplastic lens material has a refractive index in the D-line exceeding 1.65.

  As an optical resin having a high refractive index and a low birefringence, polycarbonate resin copolymers using bisphenols having a fluorene structure having a high polarizability in the side chain direction have been proposed (Patent Documents 1 and 2).

  Further, homopolycarbonate resins of ether diols having a fluorene structure having a high polarizability in the side chain direction and a phenol skeleton in the straight chain direction, or copolymers of these with bisphenols have been proposed (Patent Literature). 3 and 4).

Furthermore, a copolymer of a bisphenol having a fluorene structure having a high polarizability in the side chain direction and tricyclodecane [5.2.1.0 ^2,6 ] dimethanol has also been proposed (Patent Document 5). .

As described above, various polycarbonate resins have been proposed. However, for use as an optical material (especially a lens material), the refractive index is low, and the moldability and heat resistance are not sufficient, and the desired molding is performed. There was a problem that things could not be obtained or colored.
JP-A-6-25398 JP-A-7-109342 JP-A-10-101787 JP-A-10-101786 JP 2000-169573 A

  An object of the present invention is to solve the above problems, specifically, a polycarbonate copolymer exhibiting high transparency, high heat resistance, high moldability, high refractive index, and low birefringence, and a method for producing the same. It is an issue to provide. Moreover, this invention makes it a subject to provide the optical molding material and optical lens which are produced using the said polycarbonate copolymer.

（式中、Ｒ¹及びＲ²はそれぞれ独立して、水素原子、芳香族基を含んでもよい炭素原子数１〜９の炭化水素基、又はハロゲン原子であり；Ｘはそれぞれ、分岐していてもよい炭素原子数２〜６のアルキレン基、炭素原子数６〜１０のシクロアルキレン基、又は炭素原子数６〜１０のアリーレン基を表し；ｎ及びｍはそれぞれに独立に、１〜５の整数を示す。）で表される構成単位と、
（Ｂ）下記式（２）

（式中、Ｒ³及びＲ⁴はそれぞれ独立して、水素原子、芳香族基を含んでもよい炭素原子数１〜９の炭化水素基、又はハロゲン原子を表す。）で表される構成単位とを含み、構成単位（Ａ）と構成単位（Ｂ）とのモル比が（Ａ）：（Ｂ）＝９９：１〜６０：４０であるポリカーボネート共重合体、並びに該共重合体を少なくとも含有する組成物からなる光学用成形材料及び光学用レンズが提供される。 In order to solve the above problems, the present invention provides (A) the following formula (1):

(Wherein, R ¹ and R ² are each independently a hydrogen atom, a hydrocarbon group having 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom; Represents an alkylene group having 2 to 6 carbon atoms, a cycloalkylene group having 6 to 10 carbon atoms, or an arylene group having 6 to 10 carbon atoms; n and m are each independently an integer of 1 to 5 A structural unit represented by:
(B) The following formula (2)

(Wherein R ³ and R ⁴ each independently represents a hydrogen atom, a hydrocarbon group having 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom) A polycarbonate copolymer having a molar ratio of the structural unit (A) to the structural unit (B) of (A) :( B) = 99: 1 to 60:40, and at least the copolymer An optical molding material and an optical lens comprising the composition are provided.

  Further, in order to solve the above-mentioned problems, the present invention melt-condenses a compound that gives each of the structural units represented by formula (1) and formula (2) and a carbonic acid diester in the presence of a basic compound catalyst. A method for producing the polycarbonate copolymer.

  According to the present invention, a polycarbonate copolymer exhibiting high transparency, high heat resistance, high moldability, high refractive index, and low birefringence, and a method for producing the same can be provided. Moreover, according to this invention, the optical molding material and optical lens of favorable performance can be provided by utilizing the said polycarbonate copolymer.

  The present invention will be described in detail below. The present invention relates to a polycarbonate copolymer comprising (A) a structural unit represented by the following formula (1) and (B) a structural unit represented by the following formula (2).

In the formula, R ¹ and R ² are each independently a hydrogen atom, a hydrocarbon group having 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom; Represents a good alkylene group having 2 to 6 carbon atoms, a cycloalkylene group having 6 to 10 carbon atoms, or an arylene group having 6 to 10 carbon atoms; n and m each independently represents an integer of 1 to 5; Show.

In the formula, R ³ and R ⁴ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom.

  In this specification, the term “hydrocarbon group” is used for linear, branched and cyclic alkyl groups, alkenyl groups and alkynyl groups. In addition, these hydrocarbon groups “may contain an aromatic group” mean that a hydrogen atom bonded to a carbon atom in these groups is substituted with an aromatic group. . In the present specification, the term “aromatic group” is used for monocyclic and condensed polycyclic aromatic hydrocarbon ring groups and aromatic heterocyclic groups.

Examples of the hydrocarbon group having 1 to 9 carbon atoms represented by R ¹ , R ² , R ³ and R ^{4 in the} formulas (1) and (2) include methyl group, ethyl group, propyl group, isopropyl Group, butyl group, t-butyl group, cyclohexyl group, vinyl group, 2-propenyl group, ethynyl group, and propargyl group are included. These groups may be substituted with an aromatic group. Examples of the hydrocarbon group having 1 to 9 carbon atoms substituted with an aromatic group include a methylphenyl group, an ethylphenyl group, and a phenylpropyl group. 4-t-propylphenyl group, butylphenyl group, 4-t-butylphenyl group, phenylvinyl group, ethynylphenyl group, phenylpropargyl group, and the like. Examples of the halogen atom represented by R ¹ , R ² , R ³ and R ⁴ include a fluorine atom, a chlorine atom and a bromine atom.
R ¹ , R ² , R ³ and R ⁴ are each a hydrogen atom bonded to four carbon atoms constituting a benzene ring or a predetermined substituent, and when a plurality of substituents are present, They may be the same or different from each other. Or R ¹ to R ⁴ is a hydrogen atom, or R ¹ to R ⁴ is a substituent, the substituent is a carbon atom to which the fluorene ring is substituted (1-position) with respect to the 3-position And / or is preferably substituted at the 5-position carbon atom.

In the formula (1), preferred examples of X include ethylene group, propylene group, butylene group, pentylene group, hexylene group, isopropylene group, sec-butylene group, tert-butylene group, cyclohexylene group, and cyclohexane. A putylene group, a cyclooctylene group, a phenylene group, and a naphthylene group are included.
Moreover, in said Formula (1), it is preferable that n and m are 1-2 respectively.

  Preferred examples of the compound giving the structural unit (A) represented by the formula (1) include 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene, 9,9-bis (4- ( 2-hydroxyethoxy) -3-methylphenyl) fluorene and 9,9-bis (4- (2-hydroxyethoxy) -3,5-dimethylphenyl) fluorene. Among these, 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene is particularly preferable.

  Preferred examples of the compound giving the structural unit (B) represented by the formula (2) include 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl). ) Fluorene, 9,9-bis (4-hydroxy-3-ethylphenyl) fluorene and the like. Among these, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene is particularly preferable.

The polycarbonate copolymer of the present invention may contain two or more kinds of the structural unit (A) represented by the formula (1) and / or the structural unit (B) represented by the formula (2). Further, the polycarbonate copolymer of the present invention may contain only the structural unit (A) represented by the formula (1) and the structural unit (B) represented by the formula (2). Other structural units may be included together with (A) and (B). The other structural unit is preferably 15 mol% or less, and more preferably 10 mol% or less in the total structural units. Examples of other structural units include tricyclo (5.2.1.0 ^2,6 ) decane dimethanol, 1,4-cyclohexanedimethanol, 3,9-bis (2-hydroxy-1,1-dimethylethyl). ) -2,4,8,10-tetraoxaspiro (5.5) undecane, aliphatic diols such as isosorbide, or aromatic diols such as 2,2-bis (4-hydroxyphenyl) propane, and terephthal Constituent units formed by copolymerizing dicarboxylic acids such as acid, isophthalic acid, naphthalenedicarboxylic acid or esters thereof are included.

  In the polycarbonate copolymer of the present invention, the molar ratio of the structural unit (A) to the structural unit (B) is preferably (A) :( B) = 99: 1 to 60:40, and (A): (B) = 90: 10-60: 40 is more preferable, and (A) :( B) = 85: 15-65: 35 is more preferable. When the molar ratio of the structural unit (A) is less than 60 mol%, the fluidity is lowered and the moldability is deteriorated. As a result, the birefringence is increased, which is not suitable as an optical material. Further, the mechanical strength of the molded body is lowered. On the other hand, in the polycarbonate having only the structural unit (A) without the structural unit (B), the refractive index decreases and the glass transition temperature (Tg) decreases, that is, the heat resistance decreases. Similarly, it is not suitable as an optical material. Since the polycarbonate copolymer of the present invention contains the structural units (A) and (B) in the above ratio, it is suitable as a material for optical molded articles. In particular, it is excellent as a material for injection molded products that are exposed to relatively high temperatures and require low viscosity when melted. Moreover, since the obtained molded article shows a high refractive index (for example, about 1.65), it is particularly suitable as a material for optical lenses among optical molded articles.

  In addition, the polycarbonate copolymer of the present invention preferably has an intrinsic viscosity in the range of 0.3 to 0.6 when a solution having a concentration of 0.5 g / dl in methylene chloride as a solvent and a temperature of 20 ° C. is measured. The thing of the range of 35-0.55 is more preferable. If a material with an intrinsic viscosity of less than 0.3 is used, there will be a problem with the strength as an optical molded product after molding. On the other hand, if a material with an intrinsic viscosity of more than 0.6 is used, the melt fluidity during molding will be poor. Optical distortion unfavorable for optical molded articles increases. A polycarbonate copolymer having an intrinsic viscosity in the above range is preferable because it exhibits sufficient strength as an optical molding material, has good melt fluidity during molding, and does not cause molding distortion.

Next, the manufacturing method of the polycarbonate copolymer of this invention is demonstrated.
A preferred example of the method for producing a polycarbonate copolymer of the present invention is a mixture comprising a dihydroxy compound that gives structural units (A) and (B) and a carbonic acid diester, a basic compound catalyst, a transesterification catalyst, or both. This is a melt polycondensation method in which a reaction is carried out in the presence of a catalyst.
Examples of the carbonic acid diester include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and dicyclohexyl carbonate. Of these, diphenyl carbonate is particularly preferred. The diphenyl carbonate is preferably used in a ratio of 0.9999 to 0.9000 mol, more preferably 0.9990 to 0.9200, still more preferably 0.9900 to 0, based on 1 mol of the total of dihydroxy compounds. 9400.

  Examples of the basic compound catalyst include alkali metal compounds and / or alkaline earth metal compounds, nitrogen-containing compounds, and the like. More specifically, organic acid salts, inorganic salts, oxides, hydroxides, hydrides and alkoxides such as alkali metal and alkaline earth metal compounds; quaternary ammonium hydroxides and salts thereof; and amines; etc. Is preferred. These compounds can be used alone or in combination of two or more.

  Examples of alkali metal compounds that can be used as basic compound catalysts include sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, sodium 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, sodium borohydride, sodium benzoate, potassium benzoate, cesium benzoate, benzoic acid Lithium, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium phenyl phosphate, disodium salt of bisphenol A, 2 potassium salt, 2 cesium salt, 2 lithium salt, phenol sodium Umushio, potassium salts, cesium salts and lithium salts, and the like.

  Examples of alkaline earth metal compounds that can be used as basic compound catalysts include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium bicarbonate, calcium bicarbonate, strontium bicarbonate, barium bicarbonate, Magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, magnesium acetate, calcium acetate, strontium acetate, barium acetate, magnesium stearate, calcium stearate, calcium benzoate, magnesium phenyl phosphate and the like are included.

  Examples of nitrogen-containing compounds that can be used as basic compound catalysts include alkyls such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylbenzylammonium hydroxide, aryl, Quaternary ammonium hydroxides having a group, etc., tertiary amines such as triethylamine, dimethylbenzylamine and triphenylamine, secondary amines such as diethylamine and dibutylamine, primary amines such as propylamine and butylamine, 2 -Imidazoles such as methylimidazole, 2-phenylimidazole, benzimidazole, or ammonia, tetramethylammonium borohydride, tetrabutylammonium B hydride, tetrabutylammonium tetraphenylborate, include basic or basic salts such as tetraphenyl ammonium tetraphenylborate.

As the transesterification catalyst, a salt of zinc, tin, zirconium or lead is preferably used. These may be used alone or in combination of two or more.
Specific examples of the transesterification catalyst include zinc acetate, zinc benzoate, zinc 2-ethylhexanoate, tin (II) chloride, tin (IV) chloride, tin (II) acetate, tin (IV) acetate, dibutyltin dilaurate, Dibutyltin oxide, dibutyltin dimethoxide, zirconium acetylacetonate, zirconium oxyacetate, zirconium tetrabutoxide, lead acetate (II), lead acetate (IV) and the like are included.

These catalysts are preferably used in a ratio of 10 ⁻⁹ to 10 ⁻³ mol, more preferably 10 ⁻⁷ to 10 ⁻⁴ mol, relative to a total of 1 mol of the dihydroxy compound.

In the melt polycondensation method, the transesterification of the raw material proceeds in the presence of the catalyst under conditions of normal pressure or reduced pressure under heating, and melt polycondensation is performed while removing by-products. The reaction is generally carried out in a multistage process of two or more stages.
Specifically, the first stage reaction is performed at a temperature of about 120 to 220 ° C., preferably about 160 to 200 ° C., at a pressure of about normal pressure to about 200 Torr, for about 0.1 to 5 hours, preferably The reaction is carried out for about 0.5 to 3 hours. Next, the temperature is gradually raised to 230 to 260 ° C. which is the final temperature over 1 to 3 hours, and the pressure is gradually reduced to 1 Torr or less which is the final pressure, and the reaction is continued. Finally, the polycondensation reaction proceeds at a temperature of about 230 to 260 ° C. under a reduced pressure of 1 Torr or less. When a predetermined viscosity is reached, the pressure is restored with nitrogen and the reaction is terminated. The reaction time of 1 Torr or less is about 0.1 to 2 hours, and the total reaction time is usually about 1 to 6 hours, preferably about 2 to 5 hours.

  The reaction may be carried out continuously or batchwise. The reaction apparatus used when performing the reaction is equipped with paddle blades, lattice blades, glasses blades, etc. It may be a horizontal type or an extruder type equipped with a screw, and it is preferable to use a reactor in which these are appropriately combined in consideration of the viscosity of the polymer.

  After completion of the polymerization reaction, the catalyst is removed or deactivated in order to maintain thermal stability and hydrolysis stability. In general, a method of deactivating the catalyst by adding an acidic substance is performed. Examples of acidic substances that can be used include aromatic sulfonic acids such as p-toluenesulfonic acid; aromatic sulfonic acid esters such as butyl p-toluenesulfonate and hexyl p-toluenesulfonate; tetrabutyl dodecylbenzenesulfonate. Aromatic sulfonates such as phosphonium salts; organic halides such as stearic acid chloride, benzoyl chloride, p-toluenesulfonic acid chloride; alkyl sulfuric acids such as dimethyl sulfate; organic halides such as benzyl chloride;

  After the catalyst is deactivated, a step of devolatilizing and removing the low boiling point compound in the polymer at a pressure of 0.1 to 1 mmHg and a temperature of 200 to 350 ° C may be performed. In this step, a horizontal apparatus equipped with a stirring blade having excellent surface renewability, such as a paddle blade, a lattice blade, or a glasses blade, or a thin film evaporator is preferably used.

  The polycarbonate copolymer of the present invention includes an antioxidant, a pigment, a dye, a reinforcing agent and a filler, an ultraviolet absorber, a lubricant, a mold release agent, a crystal nucleus, in addition to the above heat stabilizer and hydrolysis stabilizer. An agent, a plasticizer, a fluidity improver, an antistatic agent, an antibacterial agent and the like can be added and used depending on the application.

  The polycarbonate copolymer of the present invention is molded into a desired shape by various molding methods and used for various applications. As described above, the polycarbonate copolymer of the present invention is suitable for various molding methods because of its excellent heat resistance and low viscosity upon melting. In particular, it is suitable for the injection molding method. Moreover, since it has low birefringence and exhibits a high refractive index (about 1.65), it is suitable as a material for optical molded products, particularly optical lenses.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In addition, the measured value was measured using the following method or apparatus.
1) Glass transition temperature (Tg): Measured at 10 ° C./min using a SEIKOSSC 5200 differential thermal scanning calorimeter (DSC).
2) Refractive index: Polycarbonate resin was press-molded into a 3 mm thick × 8 mm × 8 mm rectangular parallelepiped and measured with a refractometer manufactured by ATAGO.
3) Total light transmittance: The resin was press-molded into a 3 mm thick × 8 mm × 8 mm rectangular parallelepiped, and measured with a total light transmittance meter (MODEL1001DP manufactured by Nippon Denshoku Industries Co., Ltd.).
4) Birefringence: The birefringence of the biconvex lens produced as follows was measured with an ellipsometer manufactured by JASCO Corporation.
5) Intrinsic viscosity [η]: A solution having a concentration of 0.5 g / dl using methylene chloride as a solvent was measured at a temperature of 20 ° C.

[Example 1]
9,9-bis (4-hydroxy-3-methylphenyl) fluorene 4.15 kg (9.45 mol), 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene 6.22 kg (14.18) Mol), 5.24 kg (24.46 mol) of diphenyl carbonate, and 0.030 g (3.70 × 10 ⁻⁴ mol) of sodium hydrogen carbonate were placed in a 50 liter reactor equipped with a stirrer and a distiller, and a nitrogen atmosphere Under 760 Torr, the mixture was heated to 215 ° C. over 1 hour and stirred. Thereafter, the degree of vacuum was adjusted to 150 Torr over 15 minutes, and the transesterification reaction was carried out by maintaining for 20 minutes under the conditions of 215 ° C. and 150 Torr. Further, the temperature was raised to 250 ° C. at a rate of 37.5 ° C./hr, and held at 250 ° C. and 150 Torr for 10 minutes. Thereafter, the pressure was adjusted to 120 Torr over 10 minutes and held at 250 ° C. and 120 Torr for 70 minutes. Thereafter, the pressure was adjusted to 100 Torr over 10 minutes and held at 250 ° C. and 100 Torr for 10 minutes. The polymerization reaction was further carried out with stirring for 10 minutes under conditions of 250 ° C. and 1 Torr or less at 1 Torr or less over 40 minutes. After completion of the reaction, nitrogen was blown into the reactor to increase the pressure, and the produced polycarbonate resin was extracted while being pelletized.
10.0 kg of this polycarbonate resin was vacuum-dried at 100 ° C. for 24 hours, 500 ppm of Irganox 1010 manufactured by Ciba Specialty Chemicals and 500 ppm of Poem M300 manufactured by Riken Vitamin Co. were added to the resin, and kneaded at 260 ° C. by an extruder. And pelletized to obtain pellets. The intrinsic viscosity of this pellet was 0.41. Table 1 summarizes the measurement results of the physical properties of the obtained pellets.
The pellets were vacuum dried at 100 ° C. for 24 hours, and then injection molded at a cylinder temperature of 265 ° C. and a mold temperature of 120 ° C. to obtain a biconvex lens having a diameter of 7.9 mm. The birefringence of the convex lens was measured and found to be 109 nm, confirming that the lens had a small birefringence.

[Example 2]
9,9-bis (4-hydroxy-3-methylphenyl) fluorene 2.68 kg (7.09 mol), 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene 7.25 kg (16.54) Mol), 5.24 kg (24.46 mol) of diphenyl carbonate, and 0.030 g (3.70 × 10 ⁻⁴ mol) of sodium hydrogen carbonate were used for polymerization in the same manner as in Example 1.
10.0 kg of this polycarbonate resin was vacuum-dried at 100 ° C. for 24 hours, 500 ppm of Irganox 1010 manufactured by Ciba Specialty Chemicals and 500 ppm of Poem M300 manufactured by Riken Vitamin Co. were added to the resin, and kneaded at 260 ° C. by an extruder. And pelletized to obtain pellets. The intrinsic viscosity of this pellet was 0.45. Table 1 summarizes the measurement results of the physical properties of the obtained pellets.
The pellets were vacuum-dried at 100 ° C. for 24 hours and then injection molded at a cylinder temperature of 255 ° C. and a mold temperature of 115 ° C. to obtain a biconvex lens having a diameter of 7.9 mm. When the birefringence of the convex lens was measured, it was 56 nm, and it was confirmed that the lens was extremely low in birefringence.

[Example 3]
9,9-bis (4-hydroxy-3-methylphenyl) fluorene 1.37 kg (3.62 mol), 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene 9.00 kg (20.52) Mol), 5.35 kg (24.91 mol) of diphenyl carbonate, and 0.030 g (3.70 × 10 ⁻⁴ mol) of sodium bicarbonate were used for polymerization in the same manner as in Example 1.
10.0 kg of this polycarbonate resin was vacuum-dried at 100 ° C. for 24 hours, 500 ppm of Irganox 1010 manufactured by Ciba Specialty Chemicals and 500 ppm of Poem M300 manufactured by Riken Vitamin Co. were added to the resin, and kneaded at 260 ° C. by an extruder. And pelletized to obtain pellets. The intrinsic viscosity of this pellet was 0.49. Table 1 summarizes the measurement results of the physical properties of the obtained pellets.
The pellets were vacuum dried at 100 ° C. for 24 hours, and then injection molded at a cylinder temperature of 250 ° C. and a mold temperature of 105 ° C. to obtain a biconvex lens having a diameter of 7.9 mm. When the birefringence of the convex lens was measured, it was 32 nm, and it was confirmed that the lens was extremely low in birefringence.

[Comparative Example 1]
9,9-bis (4-hydroxy-3-methylphenyl) fluorene 1.37 kg (3.62 mol), 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene 9.00 kg (20.52) Mol) and 5.35 kg (24.91 mol) of diphenyl carbonate, and polymerization was carried out in the same manner as in Example 1.
10.0 kg of this polycarbonate resin was vacuum-dried at 100 ° C. for 24 hours, 500 ppm of Irganox 1010 manufactured by Ciba Specialty Chemicals and 500 ppm of Poem M300 manufactured by Riken Vitamin Co. were added to the resin, and kneaded at 260 ° C. by an extruder. And pelletized to obtain pellets. The intrinsic viscosity of this pellet was 0.36. The measured values of the physical properties of the obtained pellets are shown in Table 1. This pellet had a high refractive index of 1.657.
The pellets were vacuum-dried at 100 ° C. for 24 hours and then injection-molded at a cylinder temperature of 270 ° C. and a mold temperature of 125 ° C., but the melt viscosity was high and a sufficiently shaped lens could not be obtained.

[Comparative Example 2]
9,9-bis (4-hydroxy-3-methylphenyl) fluorene 1.37 kg (3.62 mol), 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene 9.00 kg (20.52) Mol) and 5.35 kg (24.91 mol) of diphenyl carbonate, and polymerization was carried out in the same manner as in Example 1.
10.0 kg of this polycarbonate resin was vacuum-dried at 100 ° C. for 24 hours, 500 ppm of Irganox 1010 manufactured by Ciba Specialty Chemicals and 500 ppm of Poem M300 manufactured by Riken Vitamin Co. were added to the resin, and kneaded at 260 ° C. by an extruder. And pelletized to obtain pellets. The intrinsic viscosity of this pellet was 0.51. The measured values of the physical properties of the obtained pellets are shown in Table 1. The pellet had a refractive index of 1.644 and was below 1.65.
The pellets were vacuum dried at 100 ° C. for 24 hours, and then injection molded at a cylinder temperature of 250 ° C. and a mold temperature of 105 ° C. to obtain a biconvex lens having a diameter of 7.9 mm. The birefringence of the convex lens was measured and found to be 28 nm, confirming that the lens was extremely low in birefringence.

[Comparative Example 3]
As a polycarbonate resin composed of bisphenol A, Iupilon H-4000 (manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was used. The measured values of the physical properties of the pellets are shown in Table 1. This pellet had a refractive index of 1.583 and was low.
The pellets were vacuum-dried at a temperature of 100 ° C. for 24 hours and then injection molded at a cylinder temperature of 255 ° C. and a mold temperature of 95 ° C. to obtain a convex lens having a diameter of 6.4 mm. When the birefringence of the convex lens was measured, it was 1280 nm, and it was found that the lens had a large birefringence and a large optical distortion.

  From the results shown in the above table, a molded article having a high refractive index (about 1.65), high heat resistance and low birefringence can be obtained by injection molding by using the polycarbonate copolymer of the example of the present invention. It can be understood that the obtained molded product exhibits good characteristics as an optical molded product.

Claims (8)

(A) The following formula (1)

(Wherein, R ¹ and R ² are each independently a hydrogen atom, a hydrocarbon group having 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom; Represents an alkylene group having 2 to 6 carbon atoms, a cycloalkylene group having 6 to 10 carbon atoms, or an arylene group having 6 to 10 carbon atoms; n and m are each independently an integer of 1 to 5 A structural unit represented by:
(B) The following formula (2)

(Wherein R ³ and R ⁴ each independently represents a hydrogen atom, a hydrocarbon group having 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom) And a molar ratio of the structural unit (A) to the structural unit (B) is (A) :( B) = 99: 1 to 60:40. The polycarbonate copolymer according to claim 1, wherein the molar ratio of the structural unit (A) to the structural unit (B) is (A) :( B) = 85: 15 to 65:35. The structural unit (A) is a structural unit derived from 9,9-bis (4- (2-hydroxyethoxyphenyl) fluorene, and the structural unit (B) is 9,9-bis (4-hydroxy-3-methyl). The polycarbonate copolymer according to claim 1 or 2, which is a structural unit derived from (phenyl) fluorene. The polycarbonate copolymer according to any one of claims 1 to 3, wherein an intrinsic viscosity measured at 20 ° C of a methylene chloride solution having a concentration of 0.5 g / dl is 0.3 to 0.6. The polycarbonate copolymer according to any one of claims 1 to 4, which has a refractive index of 1.64 or more. 6. The method according to claim 1, comprising melt polycondensation of the compound that gives each of the structural units represented by formula (1) and formula (2) with a carbonic acid diester in the presence of a basic compound catalyst. A process for producing a polycarbonate copolymer as described in 1. above. An optical molding material comprising a composition containing at least the polycarbonate copolymer according to any one of claims 1 to 5. The optical lens which consists of a composition at least containing the polycarbonate copolymer of any one of Claims 1-5.