JP6534793B2 - Polycarbonate resin and optical film - Google Patents

Description

  The present invention relates to a polycarbonate resin having a low photoelastic constant, good fluidity, excellent thermal stability, and excellent safety, and an optical film having desired wavelength dispersion characteristics.

  Conventionally, polycarbonate resins (hereinafter referred to as PC-A) obtained by reacting a carbonate precursor with 2,2-bis (4-hydroxyphenyl) propane (hereinafter referred to as bisphenol A) have transparency, heat resistance and mechanical properties. Because of their excellent properties and dimensional stability, they have been widely used in many fields as engineering plastics. Furthermore, in recent years, the use of the material as an optical material in the fields of optical disks, films, lenses and the like has been developed making use of its transparency.

  However, when PC-A is used, since it has a high positive birefringence and a high photoelastic constant, optical distortion occurs when used as an optical application, and various problems occur. For example, when it is used for an optical lens, there is a disadvantage that the birefringence of the molded article becomes large. In addition, when used as a retardation film, there is a problem that the change of birefringence due to stress is large and light leakage occurs, and the wavelength that can function as a λ / 4 plate or λ / 2 plate is limited to a specific wavelength. The

  Then, various methods are considered as a countermeasure to the said problem. As one of them, a method of obtaining a polycarbonate resin by reacting a carbonate precursor with 9,9-bis (4-hydroxyphenyl) fluorene has been proposed (Patent Documents 1 and 2). However, 9,9-bis (4-hydroxyphenyl) fluorene has a problem in the safety to the human body, and there is a problem that the skin is covered. Therefore, a polycarbonate resin comprising 9,9-bis (4-hydroxy-3-methylphenyl) fluorene has been proposed (see, for example, Patent Documents 3 and 4). However, in this polycarbonate resin, since the methyl group at the benzylic position is easily oxidized, there is a problem that it is colored at the time of injection molding or bubbles and gel are generated due to decomposition at the time of production in melt film formation. Moreover, the manufacturing method of a 9, 9-bis (4-hydroxyphenyl) fluorenes monomer is proposed (patent document 5). However, because a large amount of solvent is used for purification, there is a problem that it is not preferable to the environment.

  Therefore, polycarbonate resin that has high photoelastic constant, flowability suitable for molding, and excellent thermal stability, and can realize wavelength dispersion suitable for optical applications such as retardation films and protective films of polarizing plates And the optical film which uses it was not yet provided.

Japanese Patent Application Laid-Open No. 63-182336 Japanese Patent Application Laid-Open No. 6-145327 JP-A-11-80529 Patent No. 5119250 gazette Patent No. 4219643

  The object of the present invention is to use an optical application such as a retardation film or a protective film of a polarizing plate when it has a low photoelastic constant, good fluidity, excellent thermal stability, good safety, and a film. It is an object of the present invention to provide a polycarbonate resin capable of expressing wavelength dispersion suitable for the above and an optical film using the same.

As a result of intensive studies, the present inventors made a polycarbonate having a low photoelastic constant and excellent thermal stability by reacting a dihydroxy compound containing a host-guest complex of dihydroxyfluorenes with a carbonate precursor. It was determined that a resin could be obtained. It is common knowledge to those skilled in the art that the resin is generally polymerized using a highly purified raw material, but in the present invention, the polycarbonate is polymerized in a state of excellent safety by polymerizing in the state containing the guest compound which is an impurity. It is surprising that a resin that can be polymerized and that is of superior quality is obtained. By making this resin into a film, it has been found that wavelength dispersion suitable for optical applications such as retardation films and protective films of polarizing plates can be expressed, and the present invention has been completed.
That is, the present invention is as follows.

［式中、Ｒ_１およびＲ_２は夫々メチル基を示し、Ｒ_３およびＲ_４は夫々エチレン基を示し、ｍおよびｎは夫々０を示し、ｐおよびｑは夫々１を示す。］
２．上記１記載の未延伸フィルムの製造方法で得られた未延伸フィルムを延伸する下記式（１）を満たす光学フィルムの製造方法。
Ｒ（４５０）＜Ｒ（５５０）＜Ｒ（６５０） （１）
［但し、Ｒ（４５０）、Ｒ（５５０）およびＲ（６５０）は夫々、波長４５０ｎｍ、５５０ｎｍ、６５０ｎｍにおけるフィルム面内の位相差値を示す。］
３．ポリカーボネート樹脂の重合工程の一つの工程で、その工程の最終真空度が５０ｋＰａ以下２ｋＰａ以上の範囲で、最終樹脂温度が１６０℃以上２５０℃以下の範囲であり、減圧速度２０ｋＰａ／ｍｉｎ以下０．５ｋＰａ／ｍｉｎ以上の範囲である工程を含む上記１記載の未延伸フィルムの製造方法。 1 . A method for producing a polycarbonate resin comprising a repeating unit (A) represented by the following formula (A), which is 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene that derives the repeating unit (A) The specific viscosity measured in a methylene chloride solution at 20 ° C. is characterized by melt polymerization of a dihydroxy component containing a host guest complex with a host compound and acetonitrile or methanol as a guest compound and a carbonic diester in the presence of a polymerization catalyst. The manufacturing method of the unstretched film which obtains the polycarbonate resin which is 0.20 to 1.50, and forms the obtained polycarbonate resin by the solution casting method, the melt extrusion method, the heat press method, or the calendar method.

[Wherein, R ₁ and R ₂ each represent a methyl group, R ₃ and R ₄ each represent an ethylene group, m and n each represent 0, and p and q each represent 1. ]
2 . The manufacturing method of the optical film which satisfy | fills following formula (1) which extends | stretches the unstretched film obtained by the manufacturing method of the unstretched film of said 1 statement.
R (450) <R (550) <R (650) (1)
[Wherein, R (450), R (550) and R (650) indicate retardation values in the film plane at wavelengths of 450 nm, 550 nm, and 650 nm, respectively. ]
3 . The final resin temperature is in the range of 160 ° C. to 250 ° C. in the range of 50 kPa or less and 2 kPa or more in one step of the polymerization process of polycarbonate resin , and the pressure reduction rate is 20 kPa / min or less 0.5 kPa unstretched film production method of the above 1 Symbol placement comprising the steps is / min or more ranges.

The polycarbonate resin of the present invention can have a low photoelastic constant, flowability suitable for molding, and excellent thermal stability by reacting a carbonate precursor with a dihydroxy compound containing a host guest complex dihydroxyfluorene. It became.
Furthermore, the use of the polycarbonate resin of the present invention provides an optical film having a low photoelastic constant and excellent thermal stability and showing wavelength dispersion suitable for optical applications such as retardation films and protective films of polarizing plates. It became possible to Therefore, its industrial effects are outstanding.

Hereinafter, the present invention will be described in detail.
<Polycarbonate resin>
The polycarbonate resin of the present invention contains a repeating unit (A). 10 mol% or more in all the repeating units is preferable, 20 mol% or more is more preferable, and 30 mol% or more of a repeating unit (A) is more preferable.

(Repeating unit (A))
The repeating unit (A) used in the present invention is a repeating unit represented by the above formula (A), wherein R ₁ and R ₂ are hydrogen, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group, an aryl group Preferred is a group, an aralkyl group, an alkenyl group or a halogen group (such as a fluorine atom, a chlorine atom or a bromine atom). More preferably, they are hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, or a halogen group (such as a fluorine atom, a chlorine atom or a bromine atom).

  Specifically as a dihydroxy fluorene which derives the repeating unit represented by Formula (A), 9, 9- bis (4-hydroxyphenyl) fluorene, 9, 9- bis (4-hydroxy 3- methylphenyl) Fluorene, 9,9-bis (4-hydroxy-3-ethylphenyl) fluorene, 9,9-bis (4-hydroxy-3-n-propylphenyl) fluorene, 9,9-bis (4-hydroxy-3-3) Isopropylphenyl) fluorene, 9,9-bis (4-hydroxy-3-n-butylphenyl) fluorene, 9,9-bis (4-hydroxy-3-sec-butylphenyl) fluorene, 9,9-bis (4 -Hydroxy-3-tert-propylphenyl) fluorene, 9,9-bis (4-hydroxy-3-cyclohexylphenyl) fluorene , 9,9-bis (4-hydroxy-3-phenylphenyl) fluorene and the like. Among these, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene and 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene are preferable. Particularly preferred is 9,9-bis (4-hydroxyphenyl) fluorene.

  In the present invention, the guest compound contained in the host-guest complex is not particularly limited as long as it is a compound which forms a host-guest complex using dihydroxyfluorenes as a host compound. It is preferable to form a good host-guest complex with dihydroxyfluorenes and to facilitate distillation in a later polymerization reaction. As such a compound, a low molecular weight compound having a low boiling point and containing a hetero atom such as oxygen or nitrogen or a halogen atom in its structure is desirable. Examples of the above include nitriles such as acetonitrile, propionitrile and benzonitrile, alcohols having 1 to 4 carbon atoms such as methanol, ethanol, propanol, 2-propanol and butanol, and phenols such as phenol, cresol and xylenol. Pyridines, pyridines such as picoline, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, etc., esters such as ethyl acetate, butyl acetate, isoamyl acetate, dichloromethane, chloroform Etc. can be mentioned. Among these, acetonitrile, acetone and methanol are particularly preferable in order to form a good host-guest complex with dihydroxyfluorenes.

  The host-guest complex in the present invention can be obtained by bringing the dihydroxyfluorenes to be the host compound into contact with the guest compound. As an example of this contact method, a method of mixing a reaction mixture in which dihydroxyfluorenes are generated in any process with a guest compound or a solvent containing a guest compound, dihydroxyfluorenes recovered by any method or a crude product thereof, Examples thereof include a method of mixing with a guest compound or a solvent containing a guest compound, and a method of recrystallizing a dihydroxyfluorenes or a crude product thereof in a guest compound or a solvent containing a guest compound. Also, the host-guest complex of dihydroxyfluorenes obtained in this manner usually has a composition with a simple integer ratio such as one guest molecule or two guest molecules to one dihydroxyfluorene molecule. Control of the ratio is also easy.

(Repeating unit (B))
In a preferred embodiment of the polycarbonate resin used in the present invention, the repeating unit (A) and the repeating unit (B) are contained, and the total of the unit (A) and the unit (B) is 70 mol% or more in all repeating units. Is preferable, 80 mol% or more is more preferable, 90 mol% or more is more preferable, and 95 mol% or more is particularly preferable.

  The repeating unit (B) is a carbonate unit (B) derived from an aliphatic diol compound, an alicyclic diol compound or an aromatic dihydroxy compound. Examples of aliphatic diol compounds and alicyclic diol compounds include diol compounds described in WO 2004/111106 and WO 2011/021720, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol and the like. And oxyalkylene glycols.

As the aliphatic diol compound, an aliphatic diol compound having preferably 2 to 30 carbon atoms, more preferably 4 to 20 carbon atoms is used.
As the aliphatic diol compound, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1.9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-n-butyl-2-ethyl- 1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexane glycol, 1,2-octyl glycol, 2-ethyl 1,3-hexanediol, 2,3-diisobutyl-1,3-propanediol, 2,2-diisoamyl-1,3-propanedio Le, 2-methyl-2-propyl-1,3-propanediol.

  Examples of the alicyclic diol compound include cyclohexanediols such as 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1,4-cyclohexanediol, and the like. Cyclohexanedimethanols such as cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, norbornane dimethanols such as 2,3-norbornane dimethanol, 2,5-norbornane dimethanol, tricyclo Decane dimethanol, pentacyclopentadecane dimethanol, 1,3-adamantanediol, 2,2-adamantanediol, decalin dimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 3,9- B (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, isosorbide and the like, cyclohexanedimethanols, 3,9-bis (2- Hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane and isosorbide are preferably used.

As the aromatic dihydroxy compound, 4,4′-biphenol, 1,1-bis (4-hydroxyphenyl) ethane (bisphenol E), 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 2, 2-bis (4-hydroxy-3-methylphenyl) propane (bisphenol C), 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1 1-bis (4-hydroxyphenyl) cyclohexane (bisphenol Z), 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxyphenyl) pentane, α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene (bisphenol M), 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, 1,1-bis (4-hydroxyphenyl) decane, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4 And -hydroxy-3-methylphenyl) fluorene, 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene and the like. Among them, bisphenol A, bisphenol Z, bisphenol C, bisphenol E, and bisphenol M are preferable from the viewpoints of heat resistance and fluidity, and bisphenol A is particularly preferable from the viewpoint of high fluidity and availability.
These aliphatic diol compounds, alicyclic diol compounds and aromatic dihydroxy compounds may be used alone or in combination of two or more.

(composition)
The polycarbonate resin used in the present invention contains the unit (A) and preferably further contains the unit (B). The molar ratio (A / B) of the unit (A) to the unit (B) is preferably 10/90 to 90/10. When the molar ratio (A / B) is in the range of 10/90 to 90/10, a polycarbonate resin having a low photoelastic constant, good fluidity, and excellent thermal stability can be obtained, and has desired wavelength dispersion characteristics. An optical film is obtained. The molar ratio (A / B) of unit (A) to unit (B) is preferably 20/80 to 80/20, more preferably 25/75 to 70/30, particularly preferably 30/70 to 60 / 40 The molar ratio of each repeating unit is measured and calculated by proton NMR of JNM-AL400 manufactured by JEOL.

(Method of producing polycarbonate resin)
The polycarbonate resin of the present invention is produced by a reaction means known per se which produces a normal polycarbonate resin, for example, a method of reacting a diol component with a carbonate precursor such as phosgene or carbonic acid diester. Next, basic means of these manufacturing methods will be briefly described.

In reactions using, for example, phosgene as the carbonate precursor, the reaction is usually carried out in the presence of an acid binder and a solvent. As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used. As the solvent, for example, halogenated hydrocarbons such as methylene chloride and chlorobenzene are used. Also, catalysts such as tertiary amines or quaternary ammonium salts can be used to accelerate the reaction. At that time, the reaction temperature is usually 0 to 40 ° C., and the reaction time is several minutes to 5 hours. The polycarbonate resin of the present invention can use monofunctional phenols usually used as a termination agent in the polymerization reaction. Particularly in the case of reactions using phosgene as the carbonate precursor, monofunctional phenols are commonly used as molecular terminators for molecular weight control, and the resulting aromatic polycarbonate resins are terminally monofunctional phenols Because it is sequestered by the groups based on, it is superior in thermal stability to those not otherwise.
Such monofunctional phenols may be those which are used as end terminators for aromatic polycarbonate resins.

  Transesterification using a carbonic acid diester as a carbonate precursor is carried out by a method in which a predetermined proportion of an aromatic dihydroxy component is heated and stirred with a carbonic acid diester in an inert gas atmosphere to distill off the alcohol or phenol formed. . The reaction temperature varies depending on the boiling point of the alcohol or phenol to be produced and the like, but is usually in the range of 120 to 300 ° C. The reaction is initially completed under reduced pressure to complete the reaction while distilling off the alcohol or phenol formed. Moreover, you may add an end terminator, antioxidant, etc. as needed.

It is preferable that the manufacturing method of polycarbonate resin of this invention is a manufacturing method including A process shown below and B process.
Step A has a final degree of vacuum of 50 kPa or less and 2 kPa or more, and a final resin temperature of 160 ° C. or more and 250 ° C. or less, and the number of moles of remaining monomer is 1 mol% based on the number of moles of all diols charged. In this step, the ester is transesterified to 30 mol% or less. The final vacuum degree is more preferably in the range of 35 kPa or less and 1 kPa or more. The pressure reduction rate is preferably 20 kPa / min or less and 0.5 kPa / min or more. The heating rate is preferably 0.1 ° C./min or less and 5 ° C./min or more. When the pressure is reduced at 20 kPa / min or less or the temperature is raised at 5 ° C./min or more, bumping of the guest compound which is a low-boiling substance hardly occurs, and the production stability is excellent. The final resin temperature is more preferably in the range of 180 ° C to 240 ° C. Above 160 ° C., the reaction is easy to proceed and the productivity is good. In this step, the host-guest complex is preferably decomposed to make the amount of guest compound 0 mol% or more and 20 mol% or less with respect to the amount of host guest compound. By shifting to the next step when the amount of the guest compound is 30% or less, bumping hardly occurs during the polymerization, and the production stability is excellent.

  Step B is a step of transesterifying the specific viscosity of the polycarbonate resin to 0.2 or more and 0.6 or less at a final degree of vacuum of less than 4 kPa and a final resin temperature of 235 ° C. or more and 300 ° C. or less. In step B, the polycarbonate resin polymerized in step A is further polymerized. If the final degree of vacuum is less than 1 kPa, the produced phenols hardly remain in the system, and the hue of the resin and the decomposition reaction are suppressed, which is preferable. The final vacuum degree is more preferably 0.5 kPa or less. When the temperature is 235 ° C. or higher, the melt viscosity does not become too high, and problems such as a decrease in yield and inability to discharge can hardly occur. In addition, it is presumed that at 300 ° C. or less, the oligomers of the remaining monomers are difficult to be decomposed and gelation is difficult to occur. The final resin temperature is more preferably in the range of 240 ° C. or more and 280 ° C. or less, and still more preferably in the range of 245 ° C. or more and 275 ° C. or less. The specific viscosity of the polycarbonate resin is more preferably transesterified to 0.25 or more and 0.5 or less. The temperature is preferably gradually heated from the temperature of step A so that the final temperature is not exceeded halfway. The amount of guest compound in the resin is preferably 0.1 mol% or less based on the amount of host guest compound.

  As a carbonic diester used for the said transesterification, ester, such as a C6-C12 aryl group which may be substituted, an aralkyl group, etc. are mentioned. Specifically, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate and the like are exemplified. Among them, diphenyl carbonate is particularly preferred. The amount of diphenyl carbonate used is preferably 0.97 to 1.10 mol, more preferably 1.00 to 1.06 mol, per 1 mol in total of the dihydroxy compound.

In the melt polymerization method, a polymerization catalyst can be used to accelerate the polymerization rate, and examples of such a polymerization catalyst include alkali metal compounds, alkaline earth metal compounds, nitrogen-containing compounds, metal compounds and the like.
As such compounds, organic acid salts, inorganic salts, oxides, hydroxides, hydrides, alkoxides, quaternary ammonium hydroxides and the like of alkali metals and alkaline earth metals are preferably used, and these compounds are It can be used alone or in combination.

  Specific examples of the alkali metal compound include sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, sodium hydrogencarbonate, sodium carbonate, potassium carbonate, cesium carbonate, lithium carbonate, sodium acetate, sodium acetate, potassium acetate Cesium, lithium acetate, sodium stearate, potassium stearate, cesium stearate, lithium stearate, sodium borohydride, sodium benzoate, potassium benzoate, cesium benzoate, lithium benzoate, disodium hydrogen phosphate, phosphoric acid Dipotassium hydrogen, dilithium hydrogen phosphate, disodium phenylphosphate, disodium salt of bisphenol A, dipotassium salt of dipotassium, disodium cesium salt, dilithium salt, sodium salt of phenol, potassium salt, cesium salt, lithium salt etc. It is shown.

  Specific examples of the alkaline earth metal compound include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, magnesium diacetate, calcium diacetate, and diacetic acid. Strontium, barium diacetate and the like are exemplified.

  Specific examples of nitrogen-containing compounds include alkyls such as tetramethyl ammonium hydroxide, tetraethyl ammonium hydroxide, tetrapropyl ammonium hydroxide, tetrabutyl ammonium hydroxide, trimethyl benzyl ammonium hydroxide, etc., quaternary ammonium having an aryl group, etc. Hydroxides are exemplified. Also, tertiary amines such as triethylamine, dimethylbenzylamine and triphenylamine, and imidazoles such as 2-methylimidazole, 2-phenylimidazole and benzimidazole are exemplified. In addition, bases such as ammonia, tetramethyl ammonium borohydride, tetrabutyl ammonium borohydride, tetrabutyl ammonium tetraphenyl borate, tetraphenyl ammonium tetraphenyl borate and the like or basic salts are exemplified.

Examples of the metal compound include zinc aluminum compounds, germanium compounds, organic tin compounds, antimony compounds, manganese compounds, titanium compounds, and zirconium compounds. These compounds may be used alone or in combination of two or more.
The amount of these polymerization catalysts used is preferably 1 × 10 ⁻⁹ to 1 × 10 ⁻² equivalents, preferably 1 × 10 ⁻⁸ to 1 × 10 ⁻⁵ equivalents, more preferably 1 × to 1 mole of the diol component. It is chosen in the range of 10 ⁻⁷ to 1 × 10 ⁻³ equivalents.

  A catalyst deactivator can also be added later in the reaction. As a catalyst deactivator to be used, known catalyst deactivators are effectively used, and among them, ammonium salts and phosphonium salts of sulfonic acid are preferable. Further, salts of dodecylbenzenesulfonic acid such as tetrabutylphosphonium salt of dodecylbenzenesulfonic acid and salts of p-toluenesulfonic acid such as tetrabutylammonium salt of p-toluenesulfonic acid are preferable.

  Further, as esters of sulfonic acid, specifically, methyl benzene sulfonate, ethyl benzene sulfonate, butyl benzene sulfonate, octyl benzene sulfonate, phenyl benzene sulfonate, methyl para-toluene sulfonate, ethyl para-toluene sulfonate, para-toluene Examples thereof include butyl sulfonate, octyl p-toluenesulfonate, and phenyl p-toluenesulfonate. Among them, tetrabutylphosphonium salt of dodecylbenzenesulfonic acid is particularly preferable.

  When at least one polymerization catalyst selected from alkali metal compounds and / or alkaline earth metal compounds is used, the amount of these catalyst deactivators used is preferably 0.5 to 50 moles per mole of the catalyst. It can be used in a proportion, more preferably in a proportion of 0.5 to 10 mol, still more preferably in a proportion of 0.8 to 5 mol.

(Specific viscosity: _{SP SP} )
The specific viscosity (η _SP ) of the polycarbonate resin of the present invention is in the range of 0.20 to 1.50. A strength etc. improve that it is 0.20 or more, and a molding process characteristic is excellent in it being 1.50 or less. Preferably, it is in the range of 0.25 to 1.20, and particularly preferably in the range of 0.30 to 1.00.
The specific viscosity referred to in the present invention was determined from a solution of 0.7 g of a polycarbonate resin dissolved in 100 ml of methylene chloride at 20 ° C. using an Ostwald viscometer.
Specific viscosity (η _SP ) = (t−t ₀ ) / t ₀
[T ₀ is the second drop of methylene chloride, t is the second drop of the sample solution]

  The specific viscosity of the polycarbonate resin of the present invention can be measured in the following manner. That is, the polycarbonate resin is dissolved in 20 to 30 times its weight of methylene chloride, and the soluble matter is collected by Celite filtration, and then the solution is removed and sufficiently dried to obtain a solid of methylene chloride soluble matter. The specific viscosity at 20 ° C. of a solution of 0.7 g of the solid dissolved in 100 ml of methylene chloride is determined using an Ostwald viscometer.

(Glass transition temperature: Tg)
The glass transition temperature (Tg) of the polycarbonate resin of the present invention is preferably in the range of 130 to 220 ° C, more preferably 140 to 200 ° C, and particularly preferably 140 to 160 ° C. Heat resistance stability becomes favorable for Tg to be more than a lower limit, and when using as a retardation film, change of retardation value hardly occurs, and it is preferable. In addition, in the range where the Tg does not exceed the upper limit, it is preferable because a high temperature is not necessary for the stretching of the film, and a special processing facility different from the conventional one is not required. The Tg is estimated to be lower due to the introduction of the alkyl group. Tg is measured at a temperature rising rate of 20 ° C./min using a Model 2910 DSC manufactured by TA Instruments Japan Co., Ltd.

(Photoelastic constant)
The absolute value of the photoelastic constant of the polycarbonate resin of the present invention is preferably 50 × 10 ⁻¹² Pa ⁻¹ or less, more preferably 45 × 10 ⁻¹² Pa ⁻¹ or less, still more preferably 40 × 10 ⁻¹² Pa ^{−1. Or} less, particularly preferably 30 × 10 ⁻¹² Pa ⁻¹ or less, and most preferably 20 × 10 ⁻¹² Pa ⁻¹ or less. When the absolute value exceeds 50 × 10 ⁻¹² Pa ⁻¹ , birefringence due to stress is large, and light leakage may occur when used for a retardation film or the like. A photoelastic constant measures an unstretched film using JASCO Ltd. make Spectroellipsometer M-220.

(Additive)
In the polycarbonate resin of the present invention, a heat stabilizer, a plasticizer, a light stabilizer, a polymeric metal deactivator, a flame retardant, a lubricant, an antistatic agent, a surfactant, an antibacterial agent, and the like according to the use and necessity. Additives such as UV absorbers and mold release agents can be blended.

<Optical molded article>
An optical molded article can be formed from the polycarbonate resin of the present invention. Such an optical molded article is molded by any method such as, for example, an injection molding method, a compression molding method, an extrusion molding method, and a solution casting method. The polycarbonate resin of the present invention can be advantageously used particularly as an optical film because it has a low photoelastic constant and can achieve desired wavelength dispersion by stretching. Of course, the polycarbonate resin of the present invention has a low photoelastic constant and is also excellent in moldability, so optical disc substrates, optical lenses, liquid crystal panels, optical cards, sheets, optical fibers, connectors, evaporated plastic reflectors, displays, etc. It can also be advantageously used as an optical molding suitable for structural materials or functional material applications of optical parts. In particular, it is suitably used as an optical lens.

<Optical film>
Specifically, the optical film made of the polycarbonate resin of the present invention is used as a retardation film, a plastic substrate film, a polarizing plate protective film, an antireflective film, a brightness enhancement film, a protective film of an optical disk, a diffusion film, etc. Among them, preferred are a retardation film, a polarizing plate protective film and an antireflection film.
Examples of the method for producing an optical film include known methods such as a solution cast method, a melt extrusion method, a heat press method, and a calendar method. Among them, the solution casting method and the melt extrusion method are preferable, and in particular, the melt extrusion method is particularly preferable from the viewpoint of productivity.

  In the melt extrusion method, a method of feeding the resin to an extrusion cooling roll using a T-die is preferably used. The melt extrusion temperature at this time is determined from the molecular weight, Tg, melt flow characteristics, etc. of the polycarbonate resin, and is in the range of 180 to 350 ° C., and more preferably in the range of 200 ° C. to 320 ° C. When the temperature is lower than 180 ° C., the viscosity becomes high, and the orientation of the polymer and the stress strain tend to remain, which is not preferable. If the temperature is higher than 350 ° C., problems such as thermal deterioration, coloring, and die lines (strips) from the T die tend to occur.

  Further, since the polycarbonate resin of the present invention has good solubility in organic solvents, a solution casting method can also be applied. In the case of the solution casting method, methylene chloride, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, dioxolane, dioxane and the like are suitably used as the solvent. The amount of residual solvent in the film obtained by the solution casting method is preferably 2% by weight or less, more preferably 1% by weight or less. When the amount of residual solvent exceeds 2% by weight, the decrease in the glass transition temperature of the film becomes remarkable, which is not preferable in terms of heat resistance.

  As thickness of the unstretched film which uses the polycarbonate of this invention, the range of 30-400 micrometers is preferable, More preferably, it is the range of 40-300 micrometers. When the unstretched film is further stretched to form a retardation film, the thickness is in the range of 20 to 200 μm, more preferably 20 to 150 μm, although it is related to the target retardation value. Within this range, it is easy to obtain a desired retardation value by stretching, and film formation is also easy and preferable. The unstretched film is suitably used as a polarizing plate protective film or a transmission layer film for an optical disc.

  The unstretched film using the polycarbonate of the present invention becomes a retardation film by stretching and orientation. The machine axis direction in which the film is formed is referred to as a film forming direction or a longitudinal direction, and a direction perpendicular to the film forming direction and the thickness direction of the film is referred to as a lateral direction or a width direction. As a stretching method, known methods such as longitudinal uniaxial stretching, transverse uniaxial stretching using a tenter, simultaneous biaxial stretching combining them, sequential biaxial stretching and the like can be used. Moreover, although carrying out continuously is preferable from the point of productivity, you may carry out by a batch system. The stretching temperature is preferably in the range of (Tg-20 ° C.) to (Tg + 50 ° C.), more preferably in the range of (Tg-10 ° C.) to (Tg + 30 ° C.) relative to the glass transition temperature (Tg) of the polycarbonate resin. is there. Within this temperature range, molecular motion of the polymer is appropriate, relaxation by stretching hardly occurs, orientation control becomes easy, and a desired in-plane retardation can be easily obtained. When the stretching temperature is low, the phase difference tends to be easily developed.

The stretching ratio is determined by the target retardation value, but it is 1.05 to 5 times, more preferably 1.1 to 4 times in length and width respectively. This stretching may be performed in one step or in multiple steps. In addition, said Tg in the case of extending | stretching the unstretched film obtained by the solution casting method means the glass transition temperature containing the trace amount solvent in this unstretched film.
The thickness of the film after stretching is preferably in the range of 20 to 200 μm, more preferably 20 to 150 μm. Within this range, it is easy to obtain a desired retardation value by stretching, and film formation is also easy and preferable.

(Wavelength dispersion)
By stretching the unstretched film using the polycarbonate resin of the present invention, it has a feature that in the visible light region of wavelength 400 to 800 nm, the in-plane retardation of the film decreases as the wavelength becomes shorter. That is, the following equation (1)
R (450) <R (550) <R (650) (1)
Meet. However, R (450), R (550) and R (650) indicate the in-plane retardation value at wavelengths of 450 nm, 550 nm and 650 nm, respectively.

Here, the in-plane retardation value R is defined by the following equation, and is a characteristic that represents a delay in phase between the X direction of light transmitted in the direction perpendicular to the film and the Y direction perpendicular thereto.
_{R = (n x -n y)} × d
However, n _x is the refractive index in the main stretching direction in the film plane, n _y is the refractive index in the direction perpendicular to the main stretching direction in the film plane, and d is the thickness of the film. Here, the main stretching direction means a stretching direction in the case of uniaxial stretching, and a direction of stretching so as to increase the degree of orientation in the case of biaxial stretching, and in terms of chemical structure, the polymer main chain Indicates the orientation direction.

The following film (I) is mentioned as a preferable wavelength-dispersibility range of the optical film which uses polycarbonate resin of this invention.
(Film (I))
The film (I) is a film showing so-called reverse wavelength dispersion satisfying the following formulas (2) and (3).
0 <R (450) / R (550) <1.00 (2)
1.01 <R (650) / R (550) <2.00 (3)
The film (I) more preferably satisfies the following formulas (2-1) and (3-1).
0.60 <R (450) / R (550) <1 (2-1)
1.01 <R (650) / R (550) <1.40 (3-1)
More preferably, the following formulas (2-2) and (3-2) are satisfied.
0.65 <R (450) / R (550) <0.92 (2-2)
1.01 <R (650) / R (550) <1.30 (3-2)
Particularly preferably, the following formulas (2-3) and (3-3) are satisfied.
0.70 <R (450) / R (550) <0.91 (2-3)
1.03 <R (650) / R (550) <1.20 (3-3)

The film (I) is an unstretched film formed using the polycarbonate resin of the present invention produced at a molar ratio (A / B) of the repeating unit (A) to the repeating unit (B) in the range of 10/90 to 60/40. It is obtained by stretching a film.
The film (I) exhibits reverse wavelength dispersion, so that it is suitably used as a retardation film of a liquid crystal display device, an organic EL display device or the like without laminating. In such applications, it is desirable that 100 nm <R (550) <180 nm in the case of λ / 4 plate and 220 nm <R (550) <330 nm in the case of λ / 2 plate.

  The present invention will be described in detail by way of examples, but the present invention is not limited thereto. In the examples, "parts" means "parts by weight". The resin used and the evaluation method used in the examples are as follows.

1. Polymer composition ratio (NMR)
The polymer composition ratio (molar ratio) was measured by proton NMR of JNM-AL400 manufactured by JEOL.

2. Specific viscosity measurement It measured using the Ostwald viscometer from the solution which melt | dissolved 0.7 g of polycarbonate resin in 100 ml of methylene chlorides at 20 degreeC.
Specific viscosity (η _SP ) = (t−t ₀ ) / t ₀
[T ₀ is the second drop of methylene chloride, t is the second drop of the sample solution]

3. Glass transition temperature measurement Using a thermal analysis system DSC-2910 manufactured by TA Instruments Co., Ltd. using 8 mg of a polycarbonate resin, in a nitrogen atmosphere (nitrogen flow rate: 40 ml / min) according to JIS K7121 The temperature rise rate was measured under the condition of 20 ° C./min.

4. Pellet b value The b value of the pellet was measured using model Z-1001DP manufactured by Nippon Denshoku Co., Ltd.

5. Measurement of Photoelastic Constant The unstretched film was cut out to a size of 50 mm in the film forming direction and 10 mm in the width direction perpendicular thereto, and the sample was used to measure the photoelastic constant. It measured using JASCO Ltd. Spectroellipsometer M-220.

6. Retardation, wavelength dispersion measurement The stretched optical film was measured using JASCO Ltd. make Spectroellipsometer M-220.

7. The film material of the number of gel thickness 50μm with a color 3D laser microscope, the diameter of the major axis present in 500 mm × 1000 mm was obtained by converting the number of gels having the above interference fringe 300μm in the film 1 m ^2. The number of gels is preferably 15 pieces / m ² or less, more preferably 10 pieces / m ² or less, and particularly preferably 6 pieces / m ² or less.

8. Skin rash If the skin rash occurred in the experimenter at the time of polymer polymerization, it was x, and if it did not occur, it was ○.

[Reference Example 1]
In a reaction kettle equipped with a reflux condenser, a dropping funnel and a thermometer, 360 parts of fluorenone, 1318 parts of phenol and 4 parts of β-mercaptopropionic acid were charged, and heated and stirred at 55 ° C. for melting. While maintaining the reaction temperature at 55 ° C., 270 parts of 35% hydrochloric acid was added dropwise over 2 hours, and the mixture was further stirred at 55 ° C. for 6 hours to carry out a condensation reaction. After 270 parts of water was added to the reaction solution, hydrochloric acid was distilled off under reduced pressure together with part of phenol. To the distillation residue, 1000 parts of acetonitrile was added, and the mixture was cooled to room temperature while stirring to precipitate bisphenol fluorene-acetonitrile host guest complex crystals. The obtained crystals were filtered by suction, thoroughly washed with acetonitrile, and then dried at room temperature under reduced pressure to obtain 516 parts of dihydroxyfluorene-acetonitrile host guest complex crystals. The crystals were analyzed by gas chromatography, and the content of acetonitrile was 10.5% by weight, and the molecule was one molecule of bisphenol fluorene ((9,9-bis (4-hydroxyphenyl) fluorene), hereinafter abbreviated as BPFL). And a complex containing one molecule of acetonitrile.

[Reference Example 2]
The same operation as in Example 1 was carried out except that 1000 parts of methanol was added instead of acetonitrile in Reference Example 1, and 469 parts by weight of a BPFL.methanol host guest complex crystal was obtained. The crystals were analyzed by gas chromatography to find that the content of methanol was 4.4% by weight, and the complex contained one molecule of methanol relative to two molecules of BPFL.

[Reference Example 3]
9,9-bis (4-hydroxy-3-methylphenyl) fluorene is carried out in the same manner as in Example 1 except that 1512 parts of cresol in place of phenol and 1000 parts of acetone in place of acetonitrile are added instead of phenol. (Hereinafter abbreviated as “BCF”) 469 parts by weight of a methanol host guest complex crystal was obtained. The crystals were analyzed by gas chromatography. The acetone content was 24.4% by weight, and the complex contained 2 acetone molecules to 1 BCF molecule.

Example 1
<Manufacture of polycarbonate resin>
456 parts of BPFL obtained in Reference Example 1, commercially available 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane (hereinafter SPG) ), 750 parts of diphenyl carbonate, and 1.6 × 10 ^-4 parts of sodium hydroxide as a catalyst were heated and melted at 180 ° C. in a nitrogen atmosphere. Thereafter, the degree of pressure reduction was adjusted to 20 kPa at a pressure reduction rate of 4 kPa / min. Thereafter, the temperature was raised to 240 ° C. at a rate of 30 ° C./hr, and adjusted to 8 kPa at a pressure reduction rate of 4 kPa / min. As a result of analyzing the host-guest complex at that time by NMR, it was 1 mol% or less. Thereafter, the temperature was raised to 270 ° C. at a rate of 30 ° C./hr, and the degree of vacuum was adjusted to 1133 Pa or less over 1 hour. The reaction was carried out under stirring for a total of 4.5 hours, discharged from the bottom of the reaction vessel under nitrogen pressure, and cut with a pelletizer while cooling in a water bath to obtain pellets. The specific viscosity, glass transition temperature and thermal decomposition temperature of the pellet were measured and listed in Table 1.

<Production of optical film>
Next, attach a T-die with a width of 150 mm and a lip width of 500 μm and a film take-up device to Technobell Co., Ltd. 15 mmφ twin-screw extruder, and film-cast the obtained polycarbonate resin at 280 ° C. I got a film. The photoelastic coefficient and the number of gels of the obtained unstretched film were evaluated. Furthermore, uniaxial stretching was performed at 2.0 times at Tg + 10 ° C., and wavelength dispersion was measured. The results are shown in Table 1.

Example 2
The same operation as in Example 1 was carried out and evaluated except that the BPFL 427 part obtained in Reference Example 2 was used. The results are listed in Table 1.

[Example 3]
The same operation as in Example 1 was carried out and evaluated except that the BCF 544 part obtained in Reference Example 3 was used. The results are listed in Table 1.

Example 4
The same operation as in Example 1 was carried out and evaluated except that 402 parts of BPFL and 346 parts of 1,4-cyclohexanedimethanol (hereinafter abbreviated as CHDM) obtained in Reference Example 1 were used. The results are listed in Table 1.

[Example 5]
The same operation as in Example 1 was carried out and evaluated except that 711 parts of BPFL and 367 parts of bisphenol A (hereinafter abbreviated as BPA) obtained in Reference Example 1 were used. The results are listed in Table 1.

Comparative Example 1
The same operation as in Example 1 was carried out and evaluated except that 441 parts of commercially available BCF were used. The results are listed in Table 1.

Comparative Example 2
The same operation as in Example 1 was carried out and evaluated except that commercially available BPFL 408 was used. The results are listed in Table 1.

  The polycarbonate resin of the present invention is useful as a retardation film for liquid crystal display devices and organic EL display devices.

Claims (3)

A method for producing a polycarbonate resin comprising a repeating unit (A) represented by the following formula (A), which is 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene that derives the repeating unit (A) The specific viscosity measured in a methylene chloride solution at 20 ° C. is characterized by melt polymerization of a dihydroxy component containing a host guest complex with a host compound and acetonitrile or methanol as a guest compound and a carbonic diester in the presence of a polymerization catalyst. The manufacturing method of the unstretched film which obtains the polycarbonate resin which is 0.20 to 1.50, and forms the obtained polycarbonate resin by the solution casting method, the melt extrusion method, the heat press method, or the calendar method.

[Wherein, R ₁ and R ₂ each represent a methyl group, R ₃ and R ₄ each represent an ethylene group, m and n each represent 0, and p and q each represent 1. ] The manufacturing method of the optical film which satisfy | fills following formula (1) which extends | stretches the unstretched film obtained by the manufacturing method of the unstretched film of Claim 1 .
R (450) <R (550) <R (650) (1)
[Wherein, R (450), R (550) and R (650) indicate retardation values in the film plane at wavelengths of 450 nm, 550 nm, and 650 nm, respectively. ] The final resin temperature is in the range of 160 ° C. to 250 ° C. in the range of 50 kPa or less and 2 kPa or more in one step of the polymerization process of polycarbonate resin , and the pressure reduction rate is 20 kPa / min or less 0.5 kPa method for producing a non-stretched film according to claim 1 Symbol placement including / a min or more ranges process.