JP6801194B2 - Polycarbonate resin, a method for producing the polycarbonate resin, a method for producing a transparent film made of the polycarbonate resin, and a retardation film. - Google Patents

Description

The present invention relates to a polycarbonate resin having excellent optical properties, heat resistance, melt processability, etc., and a transparent film and a retardation film made of the polycarbonate resin.

In recent years, there has been an increasing demand for transparent resins used in optical applications such as optical lenses, optical films, and optical recording media. Among them, thin flat panel displays (FPDs) represented by liquid crystal displays and organic EL displays are particularly widespread, and improve display quality such as improvement of contrast and coloring, expansion of viewing angle, and prevention of external light reflection. Various optical films have been developed and used for this purpose.

For example, in an organic EL display, a 1/4 wave plate for preventing reflection of external light is used. Since the retardation film used for the 1/4 wave plate suppresses coloring and enables a clear black display, it is possible to obtain ideal retardation characteristics at each wavelength in the visible region, and wideband wavelength dispersion characteristics. Is required. As an equivalent of this, for example, a retardation film is disclosed which comprises a polycarbonate copolymer containing a bisphenol structure having a fluorene ring in a side chain and exhibits reverse wavelength dispersibility in which the retardation becomes smaller as the wavelength becomes shorter (there is a difference film. For example, see Patent Documents 1 and 2).

In addition, conventional polycarbonate resins have mainly used bisphenol A as a monomer, but in recent years, polycarbonate resins containing isosorbide (ISB) as a monomer component have been developed. Polycarbonate resin using ISB is excellent in various properties such as heat resistance and optical properties, and its use in optical applications such as retardation films and glass substitute applications is being studied (see, for example, Patent Documents 3 and 4). ). It is also of interest that ISB is a dihydroxy compound obtained from biomass resources and is a carbon-neutral material that does not contribute to an increase in carbon dioxide emissions even when incinerated.

Inositol is a cyclic polyhydric alcohol obtained from a biomass resource, and is expected to form a polymer by linking it with a compound that reacts with a hydroxy group. Non-Patent Documents 1 and 2 report that polyurethane was synthesized from a derivative of inositol and improved heat resistance was observed.

Japanese Patent No. 3325560 Japanese Patent No. 5119250 Japanese Patent No. 5346449 Japanese Unexamined Patent Publication No. 2012-214666

Journal of Polymer Science Part A 51.3956 (2013) Proceedings of the Society of Polymer Science, 2013, 62, 396-398

In recent years, in the use of optical films such as retardation films, the optical properties and dimensions of the films should not change during processes involving heating during the process of assembling polarizing plates and displays, or under high temperature and high humidity usage environments. , There is a demand for improved heat resistance of the material. In addition to that, there are also demands for further improvement of optical characteristics and quality, cost reduction, improvement of productivity in each process such as film formation, stretching, and lamination, and in order to meet these demands, various characteristics are simultaneously provided. It needs to be excellent. Specifically, heat resistance is improved by improving the glass transition temperature, optical properties such as wavelength dispersibility of phase difference and photoelastic coefficient, mechanical properties such as film toughness, and physical properties such as melt processability. There is a need to develop materials that have an excellent balance at a high level.

An object of the present invention is to solve the above-mentioned various problems and to obtain a polycarbonate resin excellent in various properties such as heat resistance, optical properties, melt processability, a method for producing the polycarbonate resin, and a transparent film made of the polycarbonate resin. It is an object of the present invention to provide a manufacturing method and a retardation film.

As a result of diligent studies to solve the above problems, the present inventors have determined that they contain a specific structure and control the ratio with various copolymerization components to achieve heat resistance, optical properties, melt processability, etc. We have found that a polycarbonate resin having excellent physical properties can be obtained, and have reached the present invention. That is, the gist of the present invention is as follows.

[1] A polycarbonate resin containing at least a structural unit represented by any of the following formulas (1) to (3), and the phase difference (R450) and wavelength of a stretched film made from the resin at a wavelength of 450 nm. A polycarbonate resin having a wavelength dispersion (R450 / R550) value of 0.50 or more and 1.03 or less, which is a ratio to the phase difference (R550) at 550 nm.

(In the above formulas (1) to (3), R ^{1 to} R ⁴ independently represent organic groups having 1 to 30 carbon atoms, even if these organic groups have arbitrary substituents. In addition, any two or more of R ^{1 to} R ⁴ may be bonded to each other to form a ring.)

[2] The polycarbonate resin according to [1], wherein R ¹ and R ² and R ³ and R ^{4 in the} formulas (1) to (3) form a ring with each other by an acetal bond.

[3] The polycarbonate resin according to [1] or [2], wherein the cyclohexane ring in the formulas (1) to (3) is an inositol residue derived from myo-inositol.

[4] The polycarbonate resin according to any one of [1] to [3], which contains at least a structural unit represented by the following formula (4).

[5] The polycarbonate resin according to any one of [1] to [4], wherein the glass transition temperature is 100 ° C. or higher and 180 ° C. or lower.

[6] When the total weight of all the structural units constituting the resin and the weights of the linking groups is 100% by weight, the structural unit represented by any of the above formulas (1) to (3) is 1 weight. The polycarbonate resin according to any one of [1] to [5], which contains% or more and 70% by weight or less.

[7] When the total weight of all the structural units constituting the resin and the weights of the linking groups is 100% by weight, the structural units represented by the following formula (5) are 1% by weight or more and 70% by weight or less. The polycarbonate resin according to any one of [1] to [6] contained.

[8] When the total weight of all the structural units constituting the resin and the linking groups is 100% by weight, at least one structural unit selected from the following formulas (6) to (8) is 1% by weight. The polycarbonate resin according to any one of [1] to [7], which contains 70% by weight or less.

(In the above formula (6), R ^{5 to} R ⁸ are independently hydrogen atoms, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 6 to 20 carbon atoms, respectively. Alternatively, it represents a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 6 to 20 carbon atoms, or , Substituent or unsubstituted, represents an arylene group having 6 to 20 carbon atoms. M and n are independently integers of 0 to 5.)

(In formulas (7) and (8), R ^{9 to} R ¹¹ are alkylene groups having 1 to 4 carbon atoms which may independently have a direct bond and a substituent, and are R ^{12 to} R ^{17 respectively.} Each independently has a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an aryl group having 4 to 10 carbon atoms which may have a substituent, and a substituent. An acyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms which may have a substituent, an aryloxy group having 1 to 10 carbon atoms which may have a substituent, and the like. An acyloxy group having 1 to 10 carbon atoms which may have a substituent, an amino group which may have a substituent, a vinyl group having 1 to 10 carbon atoms which may have a substituent, and a substituent. It is an ethynyl group having 1 to 10 carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group, which may have R ^{12 to} R ¹⁷ . Of these, at least two adjacent groups may be bonded to each other to form a ring.)

[9] When the total weight of all the structural units constituting the resin and the linking groups is 100% by weight, the aliphatic dihydroxy compound, the alicyclic dihydroxy compound, the dihydroxy compound containing an acetal ring, and the oxy The polycarbonate resin according to any one of [1] to [8], which contains 0.1% by weight or more and 50% by weight or less of a structural unit derived from at least one compound selected from alkylene glycol.

[10] When the total weight of all the structural units constituting the resin and the weights of the linking groups is 100% by weight, the aromatic structural units other than the structural units represented by the above formulas (6) to (8). The polycarbonate resin according to any one of [1] to [9], which contains 5% by weight or less of.

[11] The polycarbonate resin according to any one of [1] to [10], wherein the melt viscosity at a measurement temperature of 240 ° C. and a shear rate of 91.2 sec ^-1 is 1000 Pa · s or more and 7000 Pa · s or less.

[12] The residual amount of carbonic acid diester in the resin is 1 wt ppm or more and 300 wt ppm or less, and the content of the monohydroxy compound derived from the carbonic acid diester is 1 wt ppm or more and 1000 wt ppm or less [1]. ] To [11]. The polycarbonate resin according to any one of [11].

[13] A method for producing the polycarbonate resin according to any one of [1] to [12] by a melt polymerization reaction, wherein the maximum temperature of the melt polymerization reaction is 200 ° C. or higher and 260 ° C. or lower. A method for producing a polycarbonate resin.

[14] A transparent film formed by molding the polycarbonate resin according to any one of [1] to [12].

[15] The transparent film according to [14], wherein the polycarbonate resin according to any one of [1] to [12] is molded by a melt film forming method at a molding temperature of 280 ° C. or lower. Manufacturing method.

[16] A retardation film which is a unidirectional or bidirectional stretched film of the transparent film according to [14].

According to the present invention, a polycarbonate resin having excellent various properties such as heat resistance, optical properties, and melt processability, and a transparent film and a retardation film made of the polycarbonate resin are provided.

Hereinafter, embodiments of the present invention will be described in detail, but the description of the constituent elements described below is an example (typical example) of the embodiments of the present invention, and the present invention is described below as long as the gist thereof is not exceeded. Not limited to the content.

In the present invention, the "structural unit" refers to a partial structure sandwiched between adjacent linking groups in the polymer, a polymerization reactive group existing at the terminal portion of the polymer, and adjacent to the polymerization reactive group. A partial structure sandwiched between matching connecting groups.

Further, in the present invention, the carbon number of various substituents refers to the total carbon number including the carbon number of the substituent when the substituent further has a substituent.

Further, in the present invention, the polycarbonate resin includes a polyester carbonate resin. The polyester carbonate resin refers to a polymer in which the structural units constituting the polymer include not only carbonate bonds but also portions linked by ester bonds.

The polycarbonate resin of the present invention is a polycarbonate resin containing at least a structural unit represented by any of the following formulas (1) to (3), and has a phase difference (R450) at a wavelength of 450 nm and a phase difference (R550) at a wavelength of 550 nm. It is a polycarbonate resin having a wavelength dispersion (R450 / R550) value of 0.50 or more and 1.03 or less.

(In the above formulas (1) to (3), R ^{1 to} R ⁴ independently represent organic groups having 1 to 30 carbon atoms, even if these organic groups have arbitrary substituents. In addition, any two or more of R ^{1 to} R ⁴ may be bonded to each other to form a ring.)

[Structure and Raw Material of Polycarbonate Resin of the Present Invention]
(Dihydroxy compound A)
In the polycarbonate resin of the present invention, it is represented by any of the above formulas (1) to (3) when the total weight of all the structural units and the linking groups constituting the polycarbonate resin is 100% by weight. The content of the structural unit is preferably 1% by weight or more and 70% by weight or less. This ratio is more preferably 3% by weight or more and 60% by weight or less, further preferably 5% by weight or more and 50% by weight or less, and particularly preferably 8% by weight or more and 40% by weight or less. The structural units represented by the formulas (1) to (3) may be referred to as a structure (1), a structure (2), and a structure (3), respectively.

If the content of the structures (1) to (3) is larger than the above range, the heat resistance may become excessively high or the obtained resin may become brittle. In addition, therefore, it is necessary to raise the reaction temperature or lengthen the reaction time in order to proceed the polymerization reaction to a sufficient molecular weight, so that the polymer is thermally deteriorated, the color tone is significantly deteriorated, and cross-linking proceeds. There is a risk of gelling. On the other hand, when the content of the structures (1) to (3) is less than the above range, the effect of improving heat resistance, which is a feature of the polycarbonate resin of the present invention, cannot be sufficiently obtained.

In the formulas (1) to (3), R ^{1 to} R ⁴ are organic groups having 1 to 30 carbon atoms which may have independent substituents. Examples of the organic group having 1 to 30 carbon atoms of R ^{1 to} R ⁴ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group and an undecyl group. , Alkyl group such as dodecyl group, cycloalkyl group such as cyclopentyl group, cyclohexyl group, linear or branched chain alkenyl group such as vinyl group, propenyl group, hexenyl group, cyclic alkenyl such as cyclopentenyl group, cyclohexenyl group. Alkinyl group such as group, ethynyl group, methylethynyl group, 1-propionyl group, aryl group such as phenyl group, naphthyl group and toluyl group, alkoxyphenyl group such as methoxyphenyl group, aralkyl group such as benzyl group and phenylethyl group. , Thienyl group, pyridyl group, frill group and other heterocyclic groups. Of these, alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups and the like are preferable from the viewpoint of the stability of the polymer itself, and alkyl groups are preferable from the viewpoint of the optical properties and weather resistance of the polymer, and the balance between heat resistance and mechanical properties. , Cycloalkyl groups are particularly preferred.

Further, when these organic groups have a substituent, there is no particular limitation as long as it does not significantly impair the excellent physical properties of the polycarbonate resin of the present invention, but the substituent is the above-mentioned organic having 1 to 30 carbon atoms. In addition to the group, an alkoxy group, a hydroxyl group, an amino group, a carboxyl group, an ester group, a halogen atom, a thiol group, a thioether group, an organic silicon group and the like can be mentioned. The organic groups R ^{1 to} R ⁴ may have two or more of these substituents, in which case the two or more substituents may be the same or different.

In R ^{1 to} R ⁴ , two or more of them, preferably two or three, may be bonded to each other to form a ring, and in particular, R ¹ and R ² and R ³ and R ⁴ may be connected to each other. It is preferable that the ring is formed by an acetal bond from the viewpoint of improving the heat resistance of the polycarbonate resin.

In particular, among the structures (1) to (3), the structure (1) is preferable from the viewpoint of heat resistance and optical characteristics of the polycarbonate resin, and in particular, in the above formula (1), R ¹ and R ² ,. It is preferable that R ³ and R ⁴ form a ring with each other by an acetal bond.

As an example of a structure in which R ¹ and R ² , R ³ and R ⁴ form an acetal bond, and a structure in which a ring is formed by an acetal bond, those represented by the following structural formula group are preferable. Of these, cyclohexylidene groups are particularly preferable from the viewpoint of heat resistance and optical properties.

In particular, structural units contained in the polycarbonate resin of the present invention has a structure (1), in the formula (1), R ¹ and R ^2, R ³ and R ⁴ is an acetal bond cyclohexylidene group ring The structure represented by the following formula (4), in which the cyclohexane ring of the main chain is a combination of inositol residues derived from myo-inositol, makes it easy to procure raw materials and has heat resistance. It is preferable from the viewpoint of various physical properties.

The polycarbonate resin of the present invention may have only the structure (1), may have only the structure (2), may have only the structure (3), and may have only the structure (3). It may have any two of 1) to (3), and may have three structures (1) to (3) at the same time. Further, in the structures (1) to (3) of the polycarbonate resin of the present invention, R ^{1 to} R ^{4 in} each structure may be the same or different.

The above structures (1) to (3) are dihydroxy compounds represented by the following formulas (1A), (2A) and (3A) as raw material dihydroxy compounds in the method for producing a polycarbonate resin of the present invention described later, respectively. By using (hereinafter, these may be referred to as "dihydroxy compound A"), it can be introduced into the polycarbonate resin.

(In the above formulas (1A) to (3A), R ^{1 to} R ⁴ are synonymous with the above formulas (1) to (3), respectively.)

In the polycarbonate resin of the present invention, the cyclohexane ring in the structures (1) to (3) is preferably an inositol residue derived from inositol. Specific examples of the inositol include all-cis-inositol, epi-inositol, allo-inositol, muco-inositol, myo-inositol, neo-inositol, chiro-D-inositol, ciro-L-inositol, and sillo-inositol. However, from the viewpoint of easy availability of raw materials, the inositol residue derived from myo-inositol, that is, the structures (1) to (3) in the polycarbonate resin of the present invention are the polycarbonate of the present invention described later. In the method for producing a resin, it is preferable to use myo-inositol and / or a derivative thereof as a raw material dihydroxy compound.

(Dihydroxy compound B)
The polycarbonate resin of the present invention preferably contains a structural unit represented by the following formula (5).

The content of the structural unit represented by the formula (5) is 1% by weight or more and 70% by weight when the total weight of all the structural units constituting the polycarbonate resin and the linking group is 100% by weight. % Or less is preferable. This ratio is more preferably 10% by weight or more and 65% by weight or less, and particularly preferably 20% by weight or more and 60% by weight or less.

When the content of the structural unit represented by the formula (5) is larger than the above range, the heat resistance becomes excessively high, and the mechanical properties and melt processability deteriorate. Further, since the structural unit represented by the above formula (5) has a highly hygroscopic structure, the water absorption rate of the resin becomes high when the content is excessively high, and the optics of the molded product is obtained in a high humidity environment. There is a concern that the physical properties may change, or that deformation or cracking may occur. On the other hand, when the content of the structural unit represented by the formula (5) is less than the above range, the heat resistance becomes insufficient, and the high transmittance, low photoelastic coefficient, etc., which are the features of the polycarbonate resin of the present invention, etc. Optical characteristics cannot be obtained.

Examples of the dihydroxy compound into which the structural unit represented by the formula (5) can be introduced include isosorbide (ISB), isomannide, and isoidet (hereinafter, these are referred to as "dihydroxy compound B", which have a stereoisomeric relationship. There is.). One of these may be used alone, or two or more thereof may be used in combination. Of these, ISB is most preferably used from the viewpoint of availability and polymerization reactivity.

The dihydroxy compound B may contain a stabilizer such as a reducing agent, an antioxidant, an oxygen scavenger, a light stabilizer, an antacid, a pH stabilizer or a heat stabilizer. In particular, since the dihydroxy compound B is easily altered under acidic conditions, it is preferable to contain a basic stabilizer.

Examples of the basic stabilizer include hydroxides, carbonates, phosphates, phosphites, and hypophosphoruss of Group 1 or Group 2 metals in the long-period periodic table (Nomenclature of Inorganic Chemistry IUPAC Recognitions 2005). Acidates, borolates and fatty acid salts; tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, Triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide and Basic ammonium compounds such as butyltriphenylammonium hydroxide; diethylamine, dibutylamine, triethylamine, morpholine, N-methylmorpholine, pyrrolidine, piperidine, 3-amino-1-propanol, ethylenediamine, N-methyldiethanolamine, diethylethanolamine, Diethanolamine, triethanolamine, 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2-dimethyl Aminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline, etc .; amine compounds, and di- (tert-butyl) amine and 2,2,6,6-tetramethylpiperidine, etc. Hindered amine compounds can be mentioned.

The content of these basic stabilizers in the dihydroxy compound B is not particularly limited, but since the dihydroxy compound B is unstable in an acidic state, the pH of the aqueous solution of the dihydroxy compound B containing the above stabilizer is around 7. It is preferable to add a stabilizer so as to be.

If the amount of the stabilizer is too small, the effect of preventing the alteration of the dihydroxy compound B may not be obtained, and if the amount of the stabilizer is too large, the dihydroxy compound B may be denatured. It is preferably 0001% by weight to 0.1% by weight, more preferably 0.001% by weight to 0.05% by weight.

In addition, since dihydroxy compound B easily absorbs moisture and gradually deteriorates due to oxygen, prevent water from being mixed during storage or handling during manufacturing, and use an oxygen scavenger or put it in a nitrogen atmosphere. It is preferable to do so.

(Fluorene-based monomer)
The polycarbonate resin of the present invention may contain a structural unit selected from the structural units represented by the following formulas (6) to (8). Bifunctional monomers containing structural units represented by the following formulas (6) to (8) may be referred to as "fluorene-based monomers". Further, the structural units represented by the following formulas (7) and (8) may be referred to as "oligofluorene structural units".

(In the above formula (6), R ^{5 to} R ⁸ are independently hydrogen atoms, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 6 to 20 carbon atoms, respectively. Alternatively, it represents a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 6 to 20 carbon atoms, or , Substituent or unsubstituted, represents an arylene group having 6 to 20 carbon atoms. M and n are independently integers of 0 to 5.)

(In formulas (7) and (8), R ^{9 to} R ¹¹ are alkylene groups having 1 to 4 carbon atoms which may independently have a direct bond and a substituent, and are R ^{12 to} R ^{17 respectively.} Each independently has a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an aryl group having 4 to 10 carbon atoms which may have a substituent, and a substituent. An acyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms which may have a substituent, an aryloxy group having 1 to 10 carbon atoms which may have a substituent, and the like. An acyloxy group having 1 to 10 carbon atoms which may have a substituent, an amino group which may have a substituent, a vinyl group having 1 to 10 carbon atoms which may have a substituent, and a substituent. It is an ethynyl group having 1 to 10 carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group, which may have R ^{12 to} R ¹⁷ . Of these, at least two adjacent groups may be bonded to each other to form a ring.)

By introducing these structural units, it becomes possible to adjust the wavelength dispersibility (wavelength dependence) of the phase difference. Many polymers have a positive wavelength dispersibility in which the phase difference increases as the wavelength becomes shorter, but the structural units represented by the above equations (6) to (8) have a reverse wavelength in which the phase difference becomes smaller as the wavelength becomes shorter. Since it has dispersibility, it can be adjusted from flat wavelength dispersibility to inverse wavelength dispersibility according to the content of the structural units represented by the formulas (6) to (8).

The manifestation of inverse wavelength dispersion by the structural units represented by the formulas (6) to (8) differs depending on the structure, but in order to obtain the optimum wavelength dispersion characteristics as a retardation film, the formulas (6) to (8) The content of the structural unit represented by 8) is 1% by weight or more and 70% by weight or less when the total weight of all the structural units constituting the polycarbonate resin and the linking group is 100% by weight. It is preferably 3% by weight or more and 60% by weight or less, and particularly preferably 5% by weight or more and 50% by weight or less.

If the content of the structural units represented by the formulas (6) to (8) in the resin is too small, the above effect due to the inclusion of these structural units cannot be sufficiently obtained, but the above formula (6) )-(8) have negative birefringence. Therefore, when the content in the resin is larger than the above range, the birefringence becomes too small and a desired phase difference is obtained. It may not be possible. Further, since the ratio of other copolymerization components is reduced, it may be difficult to adjust the balance of other properties such as heat resistance and mechanical properties.

Specific examples of the dihydroxy compound used for introducing the structural unit represented by the formula (6) include 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene and 9,9-bis. (4-Hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9-bis (4- (2-hydroxypropoxy) phenyl) fluorene, 9,9-bis (4) -(2-Hydroxyethoxy) -3-methylphenyl) fluorene, 9,9-bis (4- (2-hydroxypropoxy) -3-methylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) 4- (2-hydroxyethoxy) ) -3-Isopropyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-isobutylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-tert- Butylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-cyclohexylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-phenylphenyl) fluorene, 9 , 9-bis (4- (2-hydroxyethoxy) -3,5-dimethylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-tert-butyl-6-methylphenyl) fluorene , 9,9-Bis (4- (3-hydroxy-2,2-dimethylpropoxy) phenyl) fluorene and the like.

Among the above dihydroxy compounds, 9,9-bis (4- (2-hydroxyethoxy) phenyl) is excellent in various properties such as heat resistance, optical properties, and mechanical properties, and is easily available. Fluorene and 9,9-bis (4-hydroxy-3-methylphenyl) fluorene are particularly preferred.

In R ⁹ and R ¹⁰ in the formulas (7) and (8), for example, the following alkylene group may be adopted as the "alkylene group having 1 to 4 carbon atoms which may have a substituent". it can.
Linear alkylene group such as methylene group, ethylene group, n-propylene group, n-butylene group; methylmethylene group, dimethylmethylene group, ethylmethylene group, propylmethylene group, (1-methylethyl) methylene group, 1 -Methylethylene group, 2-methylethylene group, 1-ethylethylene group, 2-ethylethylene group, 1-methylpropylene group, 2-methylpropylene group, 1,1-dimethylethylene group, 2,2-dimethylpropylene group , A alkylene group having a branched chain, such as a 3-methylpropylene group. Here, the positions of the branched chains in R ⁹ and R ¹⁰ are indicated by the numbers assigned so that the carbon on the fluorene ring side is at the 1st position.

The choice of R ⁹ and R ¹⁰ has a particularly important effect on the development of inverse wavelength dispersibility. The strongest reverse wavelength dispersibility is exhibited when the fluorene ring in the fluorene-based monomer structure is oriented perpendicular to the main chain direction (stretching direction). In order to bring the orientation state of the fluorene ring closer to the above-mentioned state and to exhibit strong inverse wavelength dispersibility, it is preferable to adopt R ⁹ and R ¹⁰ having 2 to 3 carbon atoms on the main chain of the alkylene group. .. When the number of carbon atoms is 1, the inverse wavelength dispersibility may not be unexpectedly shown. It is considered that this factor is that the orientation of the fluorene ring is fixed in a direction that is not perpendicular to the main chain direction due to steric hindrance of the carbonate group or ester group that is the linking group of the oligofluorene structural unit. .. On the other hand, when the number of carbon atoms is too large, the fixation of the orientation of the fluorene ring is weakened, which may weaken the inverse wavelength dispersibility. In addition, the heat resistance of the resin tends to decrease.

As shown in the formulas (7) and (8), in R ⁹ and R ¹⁰ , one end of the alkylene group is bonded to the fluorene ring and the other end is either an oxygen atom contained in the linking group or a carbonyl carbon. It is combined. From the viewpoint of thermal stability, heat resistance and reverse wavelength dispersibility, it is preferable that the other end of the alkylene group is bonded to the carbonyl carbon. As will be described later, as the monomer having an oligofluorene structure, specifically, a structure of a diol or a diester (hereinafter, the diester also includes a dicarboxylic acid) can be considered, but it is preferable to polymerize using the diester as a raw material. Further, from the viewpoint of facilitating production, it is preferable to use the same alkylene group for R ⁹ and R ¹⁰ .

In R ^11, the "alkylene group having 1 to 4 carbon atoms which may have a substituent" may be employed for example an alkylene group having up.
Linear alkylene group such as methylene group, ethylene group, n-propylene group, n-butylene group; methylmethylene group, dimethylmethylene group, ethylmethylene group, propylmethylene group, (1-methylethyl) methylene group, 1 -Methylethylene group, 2-methylethylene group, 1-ethylethylene group, 2-ethylethylene group, 1-methylpropylene group, 2-methylpropylene group, 1,1-dimethylethylene group, 2,2-dimethylpropylene group , A alkylene group having a branched chain such as a 3-methylpropylene group.

R ¹¹ preferably has 1 to 2 carbon atoms on the main chain of the alkylene group, and particularly preferably 1 carbon atom. When R ¹¹ having too many carbon atoms on the main chain is adopted, the immobilization of the fluorene ring is weakened as in R ⁹ and R ^10, and the inverse wavelength dispersibility is lowered, the photoelastic coefficient is increased, and the heat resistance is lowered. Etc. may be invited. On the other hand, the smaller the number of carbon atoms on the main chain, the better the optical characteristics and heat resistance, but when the 9-positions of the two fluorene rings are directly connected by a direct bond, the thermal stability deteriorates.

The fluorene ring contained in the oligofluorene structural unit has a structure in which all of R ^{12 to} R ¹⁷ are hydrogen atoms, or R ¹² and / or R ¹⁷ is a halogen atom, an acyl group, a nitro group, a cyano group, and a sulfo. It is preferably one selected from the group consisting of groups and one having a configuration in which R ^{13 to} R ¹⁶ are hydrogen atoms. When it has the former configuration, the compound containing the oligofluorene structural unit can be derived from fluorene, which is industrially inexpensive. Further, in the case of having the latter configuration, since the reactivity at the 9-position of the fluorene ring is improved, various induction reactions tend to be applicable in the process of synthesizing the compound containing the oligofluorene structural unit. The fluorene ring is more preferably selected from the constitution in which all of R ^{12 to} R ¹⁷ are hydrogen atoms, or the group in which R ¹² and / or R ¹⁷ consists of a fluorine atom, a chlorine atom, a bromine atom, and a nitro group. It is more preferable that R ^{13 to} R ¹⁶ are hydrogen atoms, and it is particularly preferable that all of R ^{12 to} R ¹⁷ are hydrogen atoms. By adopting the above configuration, the fluorene ratio can be increased, steric hindrance between the fluorene rings is unlikely to occur, and there is a tendency that desired optical characteristics derived from the fluorene ring can be obtained.

Among the divalent oligofluorene structural units represented by the formulas (7) and (8), the preferable structure is specifically represented by the formulas (A1) to (A6) exemplified in the following [A] group. A structure having a skeletal structure can be mentioned.

Examples of the monomer having an oligofluorene structural unit include a specific dihydroxy compound represented by the following formula (7A) and a specific diester represented by the following formula (8A).

(In the above formulas (7A) and (8A), R ^{9 to} R ¹⁷ are synonymous with those in the above formulas (7) and (8), respectively. A ¹ and A ² have a hydrogen atom or a substituent. It is an aliphatic hydrocarbon group having 1 to 18 carbon atoms, or an aromatic hydrocarbon group which may have a substituent, and A ¹ and A ² may be the same or different. Good.)

As the monomer having the divalent oligofluorene structural unit, it is preferable to use the specific diester represented by the formula (8A). The specific diester has relatively better thermal stability than the specific dihydroxy compound represented by the formula (7A), and the fluorene ring in the polymer is oriented in a preferable direction, resulting in stronger inverse wavelength dispersion. Tends to show sex. When the polycarbonate resin contains a structural unit of diester, this resin is referred to as a polyester carbonate resin.

When A ¹ and A ² of the above formula (8A) are hydrogen atoms or aliphatic hydrocarbon groups such as a methyl group and an ethyl group, the polymerization reaction is unlikely to occur under the usual polymerization conditions of polycarbonate. is there. Therefore, it is preferable that A ¹ and A ² of the above formula (8A) are aromatic hydrocarbon groups.

(Monomer with other structural units)
The polycarbonate resin of the present invention may contain a structural unit other than the above-mentioned structural unit (hereinafter, may be referred to as “other structural unit”), and the monomer containing the other structural unit may be used. Examples thereof include aliphatic dihydroxy compounds, alicyclic dihydroxy compounds, dihydroxy compounds containing an acetal ring, oxyalkylene glycols, dihydroxy compounds containing aromatic components, and diester compounds. Among these, an aliphatic dihydroxy compound, an alicyclic dihydroxy compound, a dihydroxy compound containing an acetal ring, an oxyalkylene glycol, and a dihydroxy compound containing an aromatic component are preferable from the viewpoint of increasing the reaction efficiency.

As the aliphatic dihydroxy compound, for example, the following dihydroxy compounds can be used.
Ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, 1,6-hexane Dihydroxy compounds of linear aliphatic hydrocarbons such as diols, 1,9-nonanediols, 1,10-decanediols and 1,12-dodecanediol; dihydroxys of branched aliphatic hydrocarbons such as neopentyl glycols and hexylene glycols. Compound.

As the alicyclic dihydroxy compound, for example, the following dihydroxy compounds can be used.
1,2-Cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, pentacyclopentadecanedimethanol, 2,6-decalin dimethanol, 1,5-decalindi Examples thereof include dihydroxy compounds derived from terpene compounds such as methanol, 2,3-decalin dimethanol, 2,3-norbornan dimethanol, 2,5-norbornan dimethanol, 1,3-adamantan dimethanol, and limonene. Dihydroxy compound which is a primary alcohol of alicyclic hydrocarbon; 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,3-adamantandiol, hydrogenated bisphenol A, 2,2,4,5- Dihydroxy compounds which are secondary alcohols and tertiary alcohols of alicyclic hydrocarbons, which are exemplified by tetramethyl-1,3-cyclobutanediol and the like.

As the dihydroxy compound containing an acetal ring, for example, spiroglycol represented by the following structural formula (9), dioxane glycol represented by the following structural formula (10), or the like can be used.

As the oxyalkylene glycols, for example, the following dihydroxy compounds can be used.
Diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol.

As the dihydroxy compound containing an aromatic component, for example, the following dihydroxy compounds can be used.
2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2 , 2-bis (4-hydroxy-3,5-diethylphenyl) propane, 2,2-bis (4-hydroxy- (3-phenyl) phenyl) propane, 2,2-bis (4-hydroxy- (3,3) 5-diphenyl) phenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2 , 2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) pentane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bis (4-hydroxyphenyl) diphenylmethane , 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 1,1-bis (4-hydroxyphenyl) decane, bis (4-hydroxy-3-nitrophenyl) methane, 3,3-bis ( 4-Hydroxyphenyl) pentane, 1,3-bis (2- (4-hydroxyphenyl) -2-propyl) benzene, 1,3-bis (2- (4-hydroxyphenyl) -2-propyl) benzene, 2 , 2-bis (4-hydroxyphenyl) hexafluoropropane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4'-dihydroxydiphenylsulfone, bis (4-hydroxy) Phenyl) sulfide, bis (4-hydroxy-3-methylphenyl) sulfide, bis (4-hydroxyphenyl) disulfide, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether, etc. Aromatic bisphenol compounds; 2,2-bis (4- (2-hydroxyethoxy) phenyl) propane, 2,2-bis (4- (2-hydroxypropoxy) phenyl) propane, 1,3-bis (2-hydroxy) A dihydroxy compound having an ether group bonded to an aromatic group such as ethoxy) benzene, 4,4'-bis (2-hydroxyethoxy) biphenyl, and bis (4- (2-hydroxyethoxy) phenyl) sulfone.

As the diester compound, for example, the following dicarboxylic acids and the like can be used.
Telephthalic acid, phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 4,4'-diphenoxyetanedicarboxylic acid, 4,4 Aromatic dicarboxylic acids such as'-diphenylsulfonedicarboxylic acid, 2,6-naphthalenedicarboxylic acid; 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, decalin-2,6 -Alicyclic dicarboxylic acid such as dicarboxylic acid; aliphatic dicarboxylic acid such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid and sebacic acid. These dicarboxylic acid components can be used as a raw material for polyester carbonate as the dicarboxylic acid itself, but depending on the production method, a dicarboxylic acid ester such as a methyl ester or a phenyl ester or a dicarboxylic acid such as a dicarboxylic acid halide may be used. A derivative can also be used as a raw material.

From the viewpoint of optical characteristics, it is preferable to use a structural unit that does not contain an aromatic component as the other structural unit mentioned above, but in order to maintain the optical characteristics and balance the heat resistance and mechanical characteristics. In some cases, it may be effective to incorporate an aromatic component into the main chain or side chain of the polymer. In this case, for example, the other structural unit containing an aromatic structure can introduce an aromatic component into the polymer, but these structural units in the polycarbonate resin of the present invention, that is, the above formula ( The content of the aromatic structural unit other than the structural units represented by 6) to (8) is 100% by weight when the total weight of all the structural units constituting the polycarbonate resin and the linking group is 100% by weight. It is preferably 5% by weight or less. If the amount of other structural units containing an aromatic structure is large, there is a concern that the photoelastic coefficient may deteriorate.

Examples of the monomers having the other structural units mentioned above include 1,6-hexanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 1,4-cyclohexanedimethanol, and tricyclode. It is particularly preferable to use candimethanol, spiroglycol, 1,4-cyclohexanedicarboxylic acid, decalin-2,6-dicarboxylic acid (and derivatives thereof). Resins containing structural units derived from these monomers have an excellent balance of optical properties, heat resistance, mechanical properties, and the like.

Since the polymerization reactivity of the diester compound is relatively low, it is more preferable not to use a diester compound other than the diester compound having an oligofluorene structural unit from the viewpoint of increasing the reaction efficiency.

The dihydroxy compound or diester compound for introducing other structural units may be used alone or in combination of two or more, depending on the required performance of the obtained resin. The content of other structural units in the resin is 0.1% by weight or more and 50% by weight or less when the total weight of all the structural units constituting the polycarbonate resin and the linking group is 100% by weight. Is preferable, 1% by weight or more and 45% by weight or less are more preferable, and 3% by weight or more and 40% by weight or less are particularly preferable. Other structural units mainly play a role in adjusting the heat resistance of the resin and imparting flexibility and toughness. Therefore, if the content is too small, the mechanical properties and melt processability of the resin deteriorate, and the content is high. If it is too much, the heat resistance and optical characteristics may deteriorate.

(Carbonate diester)
The linking group of the above structural unit contained in the polycarbonate resin of the present invention is introduced by polymerizing a carbonic acid diester represented by the following formula (11).

(In the formula (11), A ³ and A ⁴ are each aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, or an aromatic optionally substituted hydrocarbon a group, may be the same or different and a ³ and a ^4.)

A ³ and A ⁴ are preferably substituted or unsubstituted aromatic hydrocarbon groups, and more preferably unsubstituted aromatic hydrocarbon groups. Examples of the substituent of the aliphatic hydrocarbon group include an ester group, an ether group, an amide group and a halogen atom, and examples of the substituent of the aromatic hydrocarbon group include an alkyl group such as a methyl group and an ethyl group. Be done.

Examples of the carbonic acid diester represented by the formula (11) include diphenyl carbonate (hereinafter, may be abbreviated as DPC), substituted diphenyl carbonate such as ditril carbonate, dimethyl carbonate, diethyl carbonate and di-tert-. Examples thereof include dialkyl carbonates such as butyl carbonate, but preferred are diphenyl carbonates and substituted diphenyl carbonates, and particularly preferably diphenyl carbonates.

The carbonic acid diester may contain impurities such as chloride ions, and these impurities may inhibit the polymerization reaction or worsen the hue of the obtained resin. Therefore, if necessary, by distillation or the like. It is preferable to use a purified product.

When the polymerization reaction is carried out using both the diester monomer represented by the formula (8A) and the carbonic acid diester represented by the formula (11), A ¹ , A ² of the formula (8A) and the above. When A ³ and A ⁴ of the formula (11) all have the same structure, the components desorbed during the polymerization reaction are the same, and the components can be easily recovered and reused. Further, from the viewpoint of polymerization reactivity and usefulness in reuse, it is particularly preferable that A ^{1 to} A ⁴ are phenyl groups. When A ^{1 to} A ⁴ are phenyl groups, the component eliminated during the polymerization reaction is phenol.

[Production conditions for the polycarbonate resin of the present invention]
The polycarbonate resin of the present invention can be produced by a commonly used polymerization method. For example, it can be produced by a solution polymerization method or an interfacial polymerization method using a phosgene or a carboxylic acid halide, or a melt polymerization method in which a reaction is carried out without using a solvent. Among these production methods, it is preferable to produce by a melt polymerization method which can reduce the environmental load and is excellent in productivity because no solvent or highly toxic compound is used.

In addition, when a solvent is used for polymerization, the solvent may remain in the resin, and the plasticizing effect lowers the glass transition temperature of the resin, which causes quality fluctuations in processing processes such as molding and stretching described later. obtain. In addition, a halogen-based organic solvent such as methylene chloride is often used as the solvent, but when the halogen-based solvent remains in the resin, when a molded product using this resin is incorporated into an electronic device or the like, the metal part It can also cause corrosion. Since the resin obtained by the melt polymerization method does not contain a solvent, it is also advantageous for stabilizing the processing process and product quality.

When a polycarbonate resin is produced by a melt polymerization method, a monomer having the above-mentioned structural unit, a carbonic acid diester, and a polymerization catalyst are mixed, and a transesterification reaction (also referred to as a polycondensation reaction) is carried out under melting. The reaction rate is increased while removing the desorbed components from the system. At the end of the polymerization, the reaction proceeds to the desired molecular weight under high temperature and high vacuum conditions. When the reaction is completed, the molten resin is extracted from the reactor to obtain the polycarbonate resin of the present invention.

In the polycondensation reaction, the reaction rate and the molecular weight of the obtained resin can be controlled by strictly adjusting the molar ratio of the total dihydroxy compound and the total diester compound used in the reaction. In the case of the polycarbonate resin, the molar ratio of the carbonic acid diester to the total dihydroxy compound is preferably adjusted to 0.90 to 1.10, more preferably 0.96 to 1.05, and 0.98 to 1 It is particularly preferable to adjust to .03. In the case of the polyester carbonate resin, the molar ratio of the total amount of the carbonic acid diester and the total diester compound to the total dihydroxy compound is preferably adjusted to 0.99 to 1.10, and is adjusted to 0.96 to 1.05. It is more preferable, and it is particularly preferable to adjust it to 0.98 to 1.03.

If the molar ratio deviates significantly from the top and bottom, a resin having a desired molecular weight cannot be produced. Further, if the molar ratio becomes too small, the hydroxy group terminals of the produced resin may increase, and the thermal stability of the resin may deteriorate. In addition, a large amount of unreacted dihydroxy compound remains in the resin, which may cause stains on the molding machine or poor appearance of the molded product in the subsequent molding process. On the other hand, if the molar ratio becomes too large, the rate of transesterification reaction decreases under the same conditions, and the residual amount of carbonic acid diester or diester compound in the produced resin increases, and this residual low molecular weight component becomes Similarly, it may cause problems in the molding process.

The melt polymerization method is usually carried out in a multi-step process of two or more steps. The polycondensation reaction may be carried out in two or more steps by sequentially changing the conditions using one polymerization reactor, or by using two or more reactors and changing each condition in two or more steps. However, from the viewpoint of production efficiency, it is carried out using two or more, preferably three or more reactors. The polycondensation reaction may be a batch type, a continuous type, or a combination of a batch type and a continuous type, but a continuous type is preferable from the viewpoint of production efficiency and quality stability.

In the polycondensation reaction, it is important to appropriately control the balance between temperature and pressure in the reaction system. If either the temperature or the pressure is changed too quickly, unreacted monomers may be distilled out of the reaction system. As a result, the molar ratio of the dihydroxy compound and the diester compound changes, and a resin having a desired molecular weight may not be obtained.

Further, the polymerization rate of the polycondensation reaction is controlled by the balance between the hydroxy group terminal and the ester group terminal or the carbonate group terminal. Therefore, especially in the case of continuous polymerization, if the balance of the terminal groups fluctuates due to the distillation of the unreacted monomer, it becomes difficult to control the polymerization rate to be constant, and the molecular weight of the obtained resin may fluctuate greatly. There is. Since the molecular weight of the resin correlates with the melt viscosity, the melt viscosity fluctuates when the obtained resin is molded, which may cause problems such as the inability to obtain a molded product having uniform dimensions.

Further, when the unreacted monomer is distilled off, not only the balance of the terminal groups but also the copolymerization composition of the resin deviates from the desired composition, which may affect the mechanical properties and optical properties. In the retardation film obtained from the polycarbonate resin of the present invention, the wavelength dispersibility of the retardation is controlled by the ratio of the fluorene-based monomer in the resin and other copolymerization components. Therefore, if the ratio collapses during polymerization, the design is made. There is a risk that the desired optical characteristics will not be obtained.

Hereinafter, the steps of the melt polycondensation reaction include a step of consuming a monomer to produce an oligomer (first stage reaction) and a step of advancing the polymerization to a desired molecular weight to produce a polymer (second stage reaction). Reaction) will be described separately.

Specifically, the following conditions can be adopted as the reaction conditions in the first stage reaction. That is, the internal temperature of the polymerization reactor is usually in the range of 130 ° C. or higher, preferably 150 ° C. or higher, more preferably 170 ° C. or higher, and usually 250 ° C. or lower, preferably 240 ° C. or lower, more preferably 230 ° C. or lower. Set. The pressure of the polymerization reactor (hereinafter, the pressure represents an absolute pressure) is usually 70 kPa or less, preferably 50 kPa or less, more preferably 30 kPa or less, and usually 1 kPa or more, preferably 3 kPa or more, more preferably. Set in the range of 5 kPa or more. The reaction time is usually set in the range of 0.1 hours or more, preferably 0.5 hours or more, and usually 10 hours or less, preferably 5 hours or less, more preferably 3 hours or less.

The first-stage reaction is carried out while distilling the generated monohydroxy compound derived from the diester compound out of the reaction system. For example, when diphenyl carbonate is used as the carbonic acid diester, the monohydroxy compound distilled out of the reaction system in the first stage reaction is phenol.

In the first-stage reaction, the lower the reaction pressure, the more the polymerization reaction can be promoted, but on the other hand, the amount of unreacted monomer distilled out increases. It is effective to use a reactor equipped with a reflux condenser in order to suppress the distillation of unreacted monomers and promote the reaction by reducing the pressure. In particular, it is preferable to use a reflux condenser at the beginning of the reaction when there are many unreacted monomers.

In the second-stage reaction, the pressure of the reaction system is gradually lowered from the pressure of the first stage, and the continuously generated monohydroxy compound is removed from the reaction system, and finally the pressure of the reaction system is reduced to 5 kPa or less. It is preferably 3 kPa or less, more preferably 1 kPa or less. The internal temperature is usually set in the range of 210 ° C. or higher, preferably 220 ° C. or higher, and usually 260 ° C. or lower, preferably 255 ° C. or lower. The reaction time is usually 0.1 hours or more, preferably 0.5 hours or more, more preferably 1 hour or more, and usually 10 hours or less, preferably 5 hours or less, more preferably 3 hours or less. Set. In order to suppress side reactions such as coloring, thermal deterioration and cross-linking and obtain a resin having good hue and thermal stability, the maximum internal temperature in all reaction stages is set to 260 ° C. or lower, preferably 255 ° C. or lower, more preferably. Should be 250 ° C or lower. In particular, the dihydroxy compound A used in the present invention may be decomposed to generate a branched component when the polymerization reaction is carried out at an excessively high temperature, and the produced polymer may be crosslinked or gelled. When gel is generated, the mechanical properties of the obtained resin may be deteriorated, and when used in optical applications, it becomes a foreign substance and deteriorates the appearance quality of the product.

Transesterification reaction catalysts that can be used during polymerization (hereinafter, may be simply referred to as "catalysts" or "polymerization catalysts") are extremely dependent on the reaction rate, the color tone and thermal stability of the resin obtained by polycondensation. It can have a big impact. The catalyst is not limited as long as it can satisfy the transparency, hue, heat resistance, thermal stability, and mechanical strength of the produced resin, but is limited to Group 1 or Group 2 (hereinafter referred to as Group 1) in the long periodic table. , Simply referred to as "Group 1" and "Group 2"), and examples thereof include basic compounds such as metal compounds, basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds. Preferably, at least one metal compound selected from the group consisting of metals of Group 2 of the Long Periodic Table and lithium is used.

As the Group 1 metal compound, for example, the following compounds can be adopted, but other Group 1 metal compounds can also be adopted.
Sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, cesium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate, sodium acetate, potassium acetate, Lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium boron hydride, potassium borohydride, lithium borohydride, cesium hydride, sodium tetraphenylborate, tetraphenyl Potassium borate, lithium tetraphenylborate, cesium tetraphenylborate, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, disodium hydrogen phosphate, disodium hydrogen phosphate, dilithium hydrogen phosphate, Disodium hydrogen phosphate, disodium phenylphosphate, dipotassium phenylphosphate, dilithium phenylphosphate, dicesium phenylphosphate, sodium, potassium, lithium, alcolate of cesium, phenolate, disodium salt of bisphenol A , 2 potassium salt, 2 lithium salt, 2 cesium salt.
Of these, it is preferable to use a lithium compound from the viewpoint of polymerization activity and the hue of the obtained resin.

As the Group 2 metal compound, for example, the following compounds can be adopted, but other Group 2 metal compounds can also be adopted.
Calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, strontium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, Magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate.
Of these, it is preferable to use a magnesium compound, a calcium compound, and a barium compound, and from the viewpoint of polymerization activity and the hue of the obtained resin, it is more preferable to use a magnesium compound and / or a calcium compound, and it is more preferable to use a calcium compound. Most preferred.

It is also possible to use a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, and an amine compound in combination with the above-mentioned Group 1 metal compound and / or Group 2 metal compound. However, it is particularly preferable to use at least one metal compound selected from the group consisting of metals and lithium of Group 2 of the Long Periodic Table.

The amount of the polymerization catalyst used is usually 0.1 μmol to 300 μmol, preferably 0.5 μmol to 100 μmol, per 1 mol of the total dihydroxy compound used for the polymerization. When at least one metal compound selected from the group consisting of metals of Group 2 of the Long Periodic Table and lithium is used as the polymerization catalyst, particularly when a magnesium compound and / or a calcium compound is used, the amount of metal is used. The polymerization catalyst is usually 0.1 μmol or more, preferably 0.3 μmol or more, particularly preferably 0.5 μmol or more, per 1 mol of the total dihydroxy compound. The amount of the polymerization catalyst used is preferably 30 μmol or less, preferably 20 μmol or less, and particularly preferably 10 μmol or less as the amount of metal.

When a polyester carbonate resin is produced by using a diester compound as a monomer, a titanium compound, a tin compound, a germanium compound, an antimony compound, a zirconium compound, and a lead are used in combination with or without the basic compound. Esther exchange catalysts such as compounds, osmium compounds, zinc compounds and manganese compounds can also be used. The amount of these transesterification catalysts used is usually in the range of 1 μmol to 1 mmol, preferably in the range of 5 μmol to 800 μmol, and particularly preferably in the range of 1 μmol to 1 mmol as the metal amount with respect to 1 mol of the total dihydroxy compound used in the reaction. It is in the range of 10 μmol to 500 μmol.

If the amount of catalyst is too small, the polymerization rate becomes slow, so that the polymerization temperature must be raised by that amount in order to obtain a resin having a desired molecular weight. Therefore, there is a high possibility that the hue of the obtained resin will deteriorate, and the unreacted raw material may volatilize during the polymerization, the molar ratio of the dihydroxy compound and the diester compound may collapse, and the desired molecular weight may not be reached. There is. On the other hand, if the amount of the polymerization catalyst used is too large, unfavorable side reactions may occur, resulting in deterioration of the hue of the obtained resin and coloring or decomposition of the resin during molding.

Among the Group 1 metals, sodium, potassium, and cesium may adversely affect the hue if they are contained in a large amount in the resin. Then, these metals may be mixed not only from the catalyst used but also from the raw material or the reactor. Regardless of the source, the total amount of these metal compounds in the resin is preferably 2 μmol or less, preferably 1 μmol or less, and more preferably 0.5 μmol or less per 1 mol of the total dihydroxy compound.

The polycarbonate resin of the present invention can be polymerized as described above, then usually cooled and solidified, and pelletized with a rotary cutter or the like. The method of pelletization is not limited, but a method of extracting the polycarbonate resin from the final stage polymerization reactor in a molten state and cooling and solidifying it in the form of strands to pelletize it, or a method of pelletizing from the final stage polymerization reactor in a molten state. Polycarbonate resin is supplied to a uniaxial or biaxial extruder and melt-extruded, then cooled and solidified to be pelletized, or the polycarbonate resin is extracted from the final stage polymerization reactor in a molten state and in the form of strands. Examples thereof include a method in which the polycarbonate resin is supplied to a uniaxial or biaxial reactor again after being cooled and solidified to be pelletized, melt-extruded, and then cooled and solidified to be pelletized.

[Preferable physical properties of the polycarbonate resin of the present invention]
The molecular weight of the polycarbonate resin of the present invention thus obtained can be expressed by the reduced viscosity. If the reducing viscosity of the resin is too low, the mechanical strength of the obtained molded product may be reduced. Therefore, the reduced viscosity is usually 0.20 dL / g or more, and preferably 0.25 dL / g or more. On the other hand, if the reducing viscosity of the resin is too large, the fluidity during molding tends to decrease, and the productivity and moldability tend to decrease. Therefore, the reduced viscosity is usually 0.80 dL / g or less, preferably 0.70 dL / g or less, and more preferably 0.60 dL / g or less. The reduced viscosity is measured by using methylene chloride as a solvent, precisely adjusting the sample concentration to 0.6 g / dL, and using an Ubbelohde viscous meter at a temperature of 20.0 ° C. ± 0.1 ° C.

Since the reduced viscosity correlates with the melt viscosity of the resin, usually, the stirring power of the polymerization reactor, the discharge pressure of the gear pump that transfers the molten resin, and the like can be used as an index of operation management. That is, when the indicated value of the above-mentioned operating equipment reaches the target value, the polymerization reaction is stopped by returning the pressure of the reactor to normal pressure or extracting the resin from the reactor.

The melt viscosity of the polycarbonate resin of the present invention is preferably 1000 Pa · s or more and 7,000 Pa · s or less under the measurement conditions of a temperature of 240 ° C. and a shear rate of 91.2 sec ^-1 . The melt viscosity is more preferably 1500 Pa · s or more and 6500 Pa · s or less, and particularly preferably 2000 Pa · s or more and 6000 Pa · s or less. The melt viscosity is measured using a capillary rheometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.). When the melt viscosity is within the above range, it has sufficient mechanical properties, and melt processing becomes possible in a temperature range in which thermal deterioration of the resin can be suppressed.

The glass transition temperature of the polycarbonate resin of the present invention is preferably 100 ° C. or higher and 180 ° C. or lower. The glass transition temperature is more preferably 120 ° C. or higher and 175 ° C. or lower, and particularly preferably 130 ° C. or higher and 170 ° C. or lower. The glass transition temperature of the polycarbonate resin can be adjusted by the copolymerization ratio of the structural unit and other structural units used in the present invention. If the glass transition temperature is excessively low, the heat resistance tends to deteriorate, and the reliability of various physical properties (optical properties, mechanical properties, dimensions, etc.) of the molded product under the usage environment may deteriorate. On the other hand, if the glass transition temperature is excessively high, the resin may become brittle, the melt processability may deteriorate, the dimensional accuracy of the molded product may deteriorate, or the transparency may be impaired.

Specific methods for measuring the reduced viscosity, melt viscosity, and glass transition temperature of the polycarbonate resin of the present invention are as described in the section of Examples described later.

When a diester compound is used in the polycondensation reaction, an unreacted diester compound or a by-produced monohydroxy compound remains in the resin, so that it volatilizes during the melt processing and becomes an odor, which deteriorates the working environment or forms. It may contaminate the machine and spoil the appearance of the molded product. When diphenyl carbonate (DPC), which is a particularly useful carbonic acid diester, is used, the by-produced phenol has a relatively high boiling point, is not sufficiently removed by the reaction under reduced pressure, and tends to remain in the resin.

The carbonic acid diester-derived monohydroxy compound contained in the polycarbonate resin of the present invention is preferably 1000% by weight or less, more preferably 700% by weight or less, and particularly preferably 500% by weight or less. The residual amount of carbonic acid diester in the polycarbonate resin of the present invention is preferably 300 wt ppm or less, more preferably 200 wt ppm or less, and particularly preferably 150 wt ppm or less. It should be noted that the smaller the content of the monohydroxy compound and the carbonic acid diester is, the better in order to solve the above problem, but it is difficult to make the residual amount in the resin zero by the melt polymerization method, and for removal. Requires excessive effort. Usually, by reducing the contents of the monohydroxy compound and the carbonic acid diester to 1 wt ppm each, the above-mentioned problem can be sufficiently suppressed.

In order to reduce low molecular weight components such as carbonic acid diester-derived monohydroxy compounds and carbonic acid diesters remaining in the resin, the resin should be devolatilized with an extruder and the pressure at the end of polymerization should be 3 kPa or less. It is effective to set it to 2 kPa or less, more preferably 1 kPa or less.

When lowering the pressure at the end of polymerization, if the reaction pressure is lowered too much, the molecular weight may rise sharply, making it difficult to control the reaction. Therefore, the terminal group concentration of the resin should be excessive at the end of the hydroxy group or ester. It is preferable to carry out the production in which the base terminal is excessive and the terminal group balance is biased. The end group balance can be adjusted by the molar ratio of the total dihydroxy compound and the total diester compound charged.

The specific measurement method of the content of the monohydroxy compound derived from the carbonic acid diester of the polycarbonate resin of the present invention and the residual amount of the carbonic acid diester is as described in the section of Examples described later.

The polycarbonate resin of the present invention preferably has a refractive index (n _D ) at the sodium d line (589 nm) of 1.48 to 1.56. Further, the refractive index (n _D ) is more preferably 1.49 to 1.55, and particularly preferably 1.50 to 1.54. The smaller the refractive index, the more the surface reflection of the retardation film can be suppressed, the total light transmittance can be improved, and the optical compensation effect can be enhanced. When the polycarbonate resin of the present invention contains an aromatic structural unit in order to impart reverse wavelength dispersibility, the refractive index is higher than that of the polycarbonate resin composed only of the aliphatic structural unit, but the aromatic By minimizing the content of the group structural unit, the refractive index can be kept within the above range.

The photoelastic coefficient of the polycarbonate resin of the present invention is preferably 30 × 10 ^-12 Pa ^-1 or less, more preferably 20 × 10 ^-12 Pa ^-1 or less, and 15 × 10 ^-12 Pa ^-1 or less. Is particularly preferable. If the photoelastic coefficient is excessively large, when the retardation film is attached to the polarizing plate, the image quality may deteriorate such that the periphery of the screen becomes white and blurred. This problem is particularly noticeable when used in large display devices and flexible displays. The photoelastic coefficient of the polycarbonate resin of the present invention is preferably 7 × 10 ^-12 Pa ^-1 or more from the viewpoint of increasing the degree of freedom in controlling other physical properties of the polycarbonate resin.

The polycarbonate resin of the present invention is composed of a structural unit represented by any of the above formulas (1) to (3) and an aliphatic structural unit, and other aromatic structural units are not used. As described above, the photoelastic coefficient can be kept low.

Further, the polycarbonate resin of the present invention has a wavelength dispersion (R450 / R550) value which is a ratio of a phase difference (R450) at a wavelength of 450 nm and a phase difference (R550) at a wavelength of 550 nm of a stretched film made from the resin. Is 0.50 or more and 1.03 or less. This wavelength dispersion (R450 / R550) will be described in the section on retardation film.

Specific measurement methods for the refractive index (n _D ), photoelastic coefficient, and wavelength dispersion (R450 / R550) of the polycarbonate resin of the present invention are as described in the section of Examples described later.

[Additive]
The polycarbonate resin of the present invention contains commonly used heat stabilizers, antioxidants, catalyst deactivators, ultraviolet absorbers, light stabilizers, mold release agents, dye pigments, and impact improvements as long as the object of the present invention is not impaired. Agents, antistatic agents, lubricants, lubricants, plasticizers, compatibilizers, nucleating agents, flame retardants, inorganic fillers, foaming agents and the like may be included.

(Heat stabilizer)
If necessary, a heat stabilizer can be added to the polycarbonate resin of the present invention in order to prevent a decrease in molecular weight and a deterioration in hue during melt processing and the like. Examples of such a heat stabilizer include commonly known hindered phenol-based heat stabilizers and / or phosphorus-based heat stabilizers.

As the hindered phenolic compound, for example, the following compounds can be adopted.
2,6-Di-tert-butylphenol, 2,4-di-tert-butylphenol, 2-tert-butyl-4-methoxyphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di- tert-Butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,5-di-tert-butylhydroquinone, n-octadecyl-3- (3', 5'-di- tert-Butyl-4'-hydroxyphenyl) propionate, 2-tert-butyl-6- (3'-tert-butyl-5'-methyl-2'-hydroxybenzyl) -4-methylphenyl acrylate, 2,2' -Methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (6-cyclohexyl-4-methylphenol), 2,2'-ethylidene-bis- (2,4) -Di-tert-butylphenol), tetrakis- [methylene-3- (3', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] -methane, 1,3,5-trimethyl-2,4 , 6-Tris- (3,5-di-tert-butyl-4-hydroxybenzyl) benzene and the like. Among them, tetrakis- [methylene-3- (3', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] -methane, n-octadecyl-3- (3', 5'-di-tert-). It is preferable to use butyl-4'-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris- (3,5-di-tert-butyl-4-hydroxybenzyl) benzene.

As the phosphorus-based compound, for example, phosphorous acid, phosphoric acid, phosphonic acid, phosphonic acid, and esters thereof shown below can be adopted, but phosphorus-based compounds other than these compounds may also be adopted. It is possible.
Triphenylphosphine, tris (nonylphenyl) phosphine, tris (2,4-di-tert-butylphenyl) phosphite, tridecylphosphine, trioctylphosphine, trioctadecylphosphine, didecylmonophenylphosphine , Dioctylmonophenylphosphine, diisopropylmonophenylphosphine, monobutyldiphenylphosphine, monodecyldiphenylphosphine, monooctyldiphenylphosphine, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol Diphosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octylphosphine, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) penta Erislitol diphosphate, distearylpentaerythritol diphosphite, tributyl phosphate, triethyl phosphate, trimethyl phosphate, triphenyl phosphate, diphenyl monoorthoxenyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, 4,4'-biphenylenediphosphine Tetrakiss (2,4-di-tert-butylphenyl), dimethyl benzenephosphonate, diethyl benzenephosphonate, dipropyl benzenephosphonate.

One of these heat stabilizers may be used alone, or two or more thereof may be used in combination.

Such a heat stabilizer may be added to the reaction solution at the time of melt polymerization, or may be added to the resin using an extruder and kneaded. When a film is formed by the melt extrusion method, the heat stabilizer or the like may be added to the extruder to form the film, or the heat stabilizer or the like may be added to the resin in advance using an extruder. , Pellets or the like may be used.

When the resin is 100 parts by weight, the amount of these heat stabilizers is preferably 0.0001 parts by weight or more, more preferably 0.0005 parts by weight or more, further preferably 0.001 parts by weight or more, and further. It is preferably 1 part by weight or less, more preferably 0.5 part by weight or less, and further preferably 0.2 part by weight or less.

(Catalyst deactivator)
By adding an acidic compound to the polycarbonate resin of the present invention in order to neutralize and inactivate the catalyst used in the polymerization reaction, the color tone and thermal stability can be improved. As the acidic compound used as the catalyst deactivator, a compound having a carboxylic acid group, a phosphoric acid group, a sulfonic acid group, or an ester thereof can be used, and in particular, the following formula (12) or (13) It is preferable to use a phosphorus-based compound containing a partial structure represented by.

Examples of the phosphorus-based compound represented by the formula (12) or (13) include phosphoric acid, phosphorous acid, phosphonic acid, hypophosphoric acid, polyphosphoric acid, phosphonic acid ester, acidic phosphoric acid ester and the like. Among the above, phosphorous acid, phosphonic acid, and phosphonic acid ester are more excellent in the effects of catalytic deactivation and color suppression, and phosphorous acid is particularly preferable.

Phosphonates include phosphonic acid (phosphoric acid), methylphosphonic acid, ethylphosphonic acid, vinylphosphonic acid, decylphosphonic acid, phenylphosphonic acid, benzylphosphonic acid, aminomethylphosphonic acid, methylenediphosphonic acid, 1-hydroxyethane- Examples thereof include 1,1-diphosphonic acid, 4-methoxyphenylphosphonic acid, nitrilotris (methylenephosphonic acid), and propylphosphonic acid anhydride.

Phosphonate esters include dimethyl phosphonate, diethyl phosphonate, bis (2-ethylhexyl) phosphonate, dilauryl phosphonate, diorail phosphonate, diphenyl phosphonate, dibenzyl phosphonate, dimethyl methylphosphonate, diphenyl methylphosphonate, ethylphosphonic acid. Diethyl, diethyl benzylphosphonate, dimethyl phenylphosphonate, diethyl phenylphosphonate, dipropyl phenylphosphonate, diethyl (methoxymethyl) phosphonate, diethyl vinylphosphonate, diethyl hydroxymethylphosphonate, dimethyl (2-hydroxyethyl) phosphonate, Diethyl p-methylbenzylphosphonate, diethylphosphonoacetic acid, ethyl diethylphosphonoacetate, tert-butyl diethylphosphonoacetate, diethyl (4-chlorobenzyl) phosphonate, diethyl cyanophosphonate, diethyl cyanomethylphosphonate, 3,5 Examples thereof include -di-tert-butyl-4-hydroxybenzylphosphonate diethyl, diethylphosphonoacetaldehyde diethylacetal, and (methylthiomethyl) phosphonate diethyl.

Examples of acidic phosphoric acid esters include dimethyl phosphate, diethyl phosphate, divinyl phosphate, dipropyl phosphate, dibutyl phosphate, bis (butoxyethyl) phosphate, bis (2-ethylhexyl) phosphate, diisotridecyl phosphate, and phosphoric acid. Phosphate diesters such as dioleyl, distearyl phosphate, diphenyl phosphate, dibenzyl phosphate, or a mixture of diester and monoester, diethyl chlorophosphate, stearyl phosphate zinc salt and the like can be mentioned.

One of these may be used alone, or two or more thereof may be mixed and used in any combination and ratio.

If the amount of the phosphorus compound added to the resin is too small, the effect of catalyst deactivation and color suppression is insufficient, and if it is too large, the resin may be colored, or the durability test especially under high temperature and high humidity. In, the resin is easily colored. The amount of the phosphorus compound added corresponds to the amount of the catalyst used in the polymerization reaction. The amount of the phosphorus atom in the phosphorus compound is preferably 0.5 times mol or more and 5 times mol or less, and further 0.7 times mol or more and 4 times mol or less with respect to 1 mol of the catalyst metal used in the polymerization reaction. It is preferable, and particularly preferably 0.8 times mol or more and 3 times mol or less.

(Polymer alloy)
The polycarbonate resin of the present invention has aromatic polycarbonate, aromatic polyester, aliphatic polyester, polyamide, polystyrene, polyolefin, acrylic, amorphous polyolefin, ABS, AS, for the purpose of modifying properties such as mechanical properties and solvent resistance. It may be a polymer alloy prepared by kneading one or more kinds of synthetic resin such as polylactic acid and polybutylene succinate and rubber and the like.

The above-mentioned additives and modifiers are prepared by adding the above-mentioned components to the resin used in the present invention at the same time or in an arbitrary order by a mixer such as a tumbler, a V-type blender, a Nauter mixer, a Banbury mixer, a kneading roll, or an extruder. Although it can be produced by mixing, kneading with an extruder, particularly a twin-screw extruder, is preferable from the viewpoint of improving dispersibility.

[Transparent film and retardation film]
The transparent film of the present invention is formed by molding the polycarbonate resin of the present invention.
Further, the retardation film of the present invention is formed by stretching the transparent film of the present invention in at least one direction.
Hereinafter, the transparent film of the present invention may be referred to as an "unstretched film".

(Manufacturing method of unstretched film)
As a method for forming an unstretched film using the polycarbonate resin of the present invention, a casting method in which the resin is dissolved in a solvent and cast, and then the solvent is removed, or a resin is melted without using a solvent. A melt film forming method for forming a film can be adopted. Specific examples of the melt film forming method include a melt extrusion method using a T-die, a calender molding method, a hot press method, a coextrusion method, a comelt method, a multi-layer extrusion method, and an inflation molding method. The method for forming the unstretched film is not particularly limited, but the casting method may cause problems due to the residual solvent. Therefore, the melt film forming method, particularly the T-die is used because of the ease of subsequent stretching treatment. The melt extrusion method used is preferable.

When the unstretched film is molded by the melt film forming method, the molding temperature is preferably 280 ° C. or lower, more preferably 270 ° C. or lower, and particularly preferably 265 ° C. or lower. If the molding temperature is too high, defects due to the generation of foreign matter and bubbles in the obtained film may increase, and the film may be colored. However, if the molding temperature is too low, the melt viscosity of the resin becomes too high, which makes it difficult to mold the raw film, and it may be difficult to produce an unstretched film having a uniform thickness. The lower limit is usually 200 ° C. or higher, preferably 210 ° C. or higher, and more preferably 220 ° C. or higher. In the present invention, the molding temperature is the temperature at the time of molding in the melt film forming method, and is a value obtained by measuring the resin temperature at the die outlet for extruding the molten resin.

Further, if a foreign substance is present in the film, it is recognized as a defect such as light leakage when used as a polarizing plate. In order to remove foreign substances in the resin, a method in which a polymer filter is attached after the extruder, the resin is filtered, and then extruded from a die to form a film is preferable. At that time, it is necessary to connect the extruder, polymer filter, and die with piping and transfer the molten resin, but in order to suppress thermal deterioration in the piping as much as possible, arrange each equipment so that the residence time is the shortest. This is very important. In addition, the process of transporting and winding the film after extrusion is performed in a clean room, and the utmost care is required to prevent foreign matter from adhering to the film.

The thickness of the unstretched film is determined according to the design of the film thickness of the retardation film after stretching and the stretching conditions such as the stretching ratio. However, if it is too thick, thickness unevenness is likely to occur, and if it is too thin, it is likely to occur during transportation or stretching. It is usually 30 μm or more, preferably 40 μm or more, more preferably 50 μm or more, and usually 200 μm or less, preferably 160 μm or less, still more preferably 120 μm or less, because it may cause breakage. Further, if the unstretched film has thickness unevenness, the retardation unevenness of the retardation film is caused. Therefore, the thickness of the portion used as the retardation film is preferably ± 3 μm or less, and the set thickness is ± 2 μm or less. It is more preferable that the thickness is ± 1 μm or less.

The length of the unstretched film in the longitudinal direction is preferably 500 m or more, more preferably 1000 m or more, and particularly preferably 1500 m or more. From the viewpoint of productivity and quality, when producing the retardation film of the present invention, it is preferable to continuously stretch the film, but usually, it is necessary to adjust the conditions in order to adjust to a predetermined retardation at the start of stretching. If the length of the film is too short, the amount of products that can be obtained after adjusting the conditions will decrease. In the present specification, the term "long" means that the dimension of the film in the longitudinal direction is sufficiently larger than that in the width direction of the film, and that the film can be wound in the longitudinal direction to form a coil. means. More specifically, it means that the dimension in the longitudinal direction of the film is 10 times or more larger than the dimension in the width direction.

The unstretched film obtained as described above preferably has an internal haze of 3% or less, more preferably 2% or less, and particularly preferably 1% or less. If the internal haze of the unstretched film is larger than the upper limit value, light scattering may occur, which may cause depolarization when laminated with a polarizer, for example. The lower limit of the internal haze is not specified, but is usually 0.1% or more. For the measurement of internal haze, a transparent film with adhesive that had been measured for haze in advance was attached to both sides of the unstretched film, and a sample with the influence of external haze removed was used. The value obtained by subtracting the haze value from the measured value of the sample is used as the internal haze value.

Further, the b * value of the unstretched film is preferably 3 or less. If the b * value of the film is too large, problems such as coloring will occur. The b * value is more preferably 2 or less, and particularly preferably 1 or less. The b * value is measured using a spectrophotometer CM-2600d manufactured by Konica Minolta Co., Ltd.

Regardless of the thickness of the unstretched film, the total light transmittance of the film itself is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more. When the total light transmittance is equal to or higher than the above lower limit, a film with less coloring can be obtained, and when bonded to a polarizing plate, a circular polarizing plate having high degree of polarization and transmittance is obtained, which is high when used in an image display device. It is possible to realize display quality. The upper limit of the total light transmittance of the unstretched film is not particularly limited, but is usually 99% or less.
A specific method for measuring the total light transmittance of the unstretched film is as described in the section of Examples described later.

(Manufacturing method of retardation film)
A retardation film can be obtained by stretching and orienting the unstretched film in at least one direction. As the stretching method, known methods such as longitudinal uniaxial stretching, horizontal uniaxial stretching using a tenter or the like, simultaneous biaxial stretching combining them, and sequential biaxial stretching can be used. The stretching may be carried out in batch, but continuous stretching is preferable in terms of productivity. Further, as compared with the batch type, a continuous retardation film can be obtained with less variation in the phase difference in the film plane.

The stretching temperature is usually in the range of (Tg-20 ° C.) to (Tg + 30 ° C.), preferably (Tg-10 ° C.) to (Tg + 20 ° C.), with respect to the glass transition temperature (Tg) of the resin used as the raw material. More preferably, it is in the range of (Tg-5 ° C.) to (Tg + 15 ° C.). The draw ratio is determined by the target phase difference value, but is 1.2 times to 4 times, more preferably 1.5 times to 3.5 times, and further preferably 2 times to 3 times, respectively, in the vertical direction and the horizontal direction. .. If the draw ratio is too small, the effective range in which the desired degree of orientation and orientation angle can be obtained is narrowed. On the other hand, if the draw ratio is too large, the film may be broken or wrinkled during stretching.

The stretching speed is also appropriately selected depending on the intended purpose, but the strain rate represented by the following formula is usually 50% to 2000%, preferably 100% to 1500%, more preferably 200% to 1000%, and particularly preferably 250. It can be selected to be% to 500%. If the stretching speed is excessively high, it may cause breakage during stretching, or the optical characteristics may fluctuate greatly due to long-term use under high temperature conditions. Further, if the stretching speed is excessively low, not only the productivity is lowered, but also the stretching ratio may have to be excessively increased in order to obtain a desired phase difference.
Strain rate (% / min) = {stretching rate (mm / min) /
Raw film length (mm)} x 100

After stretching the film, heat fixing treatment may be performed in a heating furnace, if necessary, or a relaxation step may be performed by controlling the width of the tenter or adjusting the peripheral speed of the roll. The temperature of the heat fixing treatment is usually in the range of 60 ° C. to (Tg), preferably 70 ° C. to (Tg-5 ° C.) with respect to the glass transition temperature (Tg) of the resin used for the unstretched film. If the heat treatment temperature is too high, the orientation of the molecules obtained by stretching may be disturbed, which may greatly reduce the desired phase difference. Further, when the relaxation step is provided, the stress generated in the stretched film can be removed by shrinking the width of the film expanded by stretching to 95% to 99%. The treatment temperature applied to the film at this time is the same as the heat fixing treatment temperature. By performing the heat fixing treatment and the relaxation step as described above, it is possible to suppress fluctuations in optical characteristics due to long-term use under high temperature conditions.

The retardation film of the present invention can be produced by appropriately selecting and adjusting the processing conditions in such a stretching step.

A specific method for measuring the birefringence (Δn) of the retardation film is as described in the section of Examples described later.

The retardation film of the present invention preferably has a thickness of 70 μm or less, although it depends on the design value of the retardation. The thickness of the retardation film is more preferably 60 μm or less, further preferably 55 μm or less, and particularly preferably 50 μm or less. On the other hand, if the thickness is excessively thin, it becomes difficult to handle the film, and wrinkles or breakage occur during production. Therefore, the lower limit of the thickness of the retardation film of the present invention is preferably 10 μm or more. More preferably, it is 15 μm or more.

The retardation film of the present invention, which is a stretched film produced by using the polycarbonate resin of the present invention, has a wavelength that is the ratio of the retardation (R450) measured at a wavelength of 450 nm to the retardation (R550) measured at a wavelength of 550 nm. The value of the dispersion (R450 / R550) is 0.50 or more and 1.03 or less. In applications where flat wavelength dispersion is preferably used, the value of wavelength dispersion (R450 / R550) is more preferably 0.98 or more and 1.02 or less, and more preferably 0.99 or more and 1.01 or less. It is particularly preferable to have. When used for a 1/4 wave plate, the value of wavelength dispersion (R450 / R550) is more preferably 0.70 or more and 0.96 or less, and more preferably 0.75 or more and 0.94 or less. It is more preferable, and it is particularly preferable that it is 0.78 or more and 0.92 or less.

When the value of the wavelength dispersion (R450 / R550) is in this range, ideal phase difference characteristics can be obtained in a wide wavelength range in the visible region. For example, by producing a retardation film having such wavelength dependence as a 1/4 wave plate and bonding it with a polarizing plate, a circular polarizing plate or the like can be produced, and polarized light having less wavelength dependence of hue can be produced. It is possible to realize a board and a display device. On the other hand, when the wavelength dispersion (R450 / R550) is out of this range, the wavelength dependence of the hue becomes large, optical compensation is not performed at all wavelengths in the visible region, and light passes through the polarizing plate and the display device. This causes problems such as coloring and deterioration of contrast.

[Use]
The use of the transparent film of the present invention is not particularly limited, but the phase difference used in various liquid crystal display devices, mobile devices, etc., by taking advantage of its excellent physical properties such as heat resistance, optical properties, and melt processability. It is suitable for optical films such as films.

For example, the retardation film of the present invention obtained by stretching the transparent film of the present invention is laminated and laminated with a known polarizing film and cut to a desired size to form a circular polarizing plate. Such circular polarizing plates are used, for example, for viewing angle compensation of various displays (liquid crystal display device, organic EL display device, plasma display device, FED electric field emission display device, SED surface electric field display device), for preventing reflection of external light, and for color. It can be used for compensation, conversion of linearly polarized light to circular polarization, etc.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded. The characteristics of the resin, transparent film (unstretched film) and retardation film of the present invention were evaluated by the following methods. The characteristic evaluation method is not limited to the following methods, and can be appropriately selected by those skilled in the art.

(1) Measurement of Reducing Viscosity A resin sample was dissolved in methylene chloride to accurately prepare a resin solution having a concentration of 0.6 g / dL. Using a Ubbelohde viscous tube manufactured by Moriyu Rika Kogyo Co., Ltd., the measurement was carried out at a temperature of 20.0 ° C. ± 0.1 ° C., and the solvent passage time t ₀ and the solution passage time t were measured. Using the obtained values of t ₀ and t, the relative viscosity η _ll was obtained by the following formula (i), and further, the specific viscosity η _sp was obtained by the following formula (ii) using the obtained relative viscosity η _ll . ..
η _rel = t / t ₀ (i)
η _sp = (η − η ₀ ) / η ₀ = η _rel -1 (ii)
Then, the obtained specific viscosity η _sp was divided by the concentration c [g / dL] to obtain the reduced viscosity η _sp / c.

(2) Measurement of melt viscosity A pellet-shaped resin sample was vacuum-dried at 90 ° C. for 5 hours or more. The dried pellets were measured with a capillary rheometer manufactured by Toyo Seiki Seisakusho Co., Ltd. Measurement temperature was 240 ° C., measured melt viscosity between shear rate 9.12~1824sec ^-1, using a value of melt viscosity at 91.2sec ^-1. The orifice having a die diameter of φ1 mm × 10 mm L was used.

(3) Measurement of glass transition temperature (Tg) The measurement was performed using a differential scanning calorimeter DSC6220 manufactured by SII Nanotechnology. About 10 mg of a resin sample was placed in an aluminum pan manufactured by the same company, sealed, and heated from 30 ° C. to 250 ° C. at a heating rate of 20 ° C./min under a nitrogen stream of 50 mL / min. After maintaining the temperature for 3 minutes, it was cooled to 30 ° C. at a rate of 20 ° C./min. The temperature was maintained at 30 ° C. for 3 minutes, and the temperature was raised again to 200 ° C. at a rate of 20 ° C./min. From the DSC data obtained by the second temperature rise, a straight line extending the baseline on the low temperature side to the high temperature side and a tangent line drawn at the point where the slope of the curve of the stepwise change part of the glass transition is maximized. The temperature at which the outer glass transition started, which is the temperature at the intersection of the above, was determined and used as the glass transition temperature. A resin having a high glass transition temperature is excellent in terms of heat resistance.

(4) Measurement of the content of monohydroxy compound and carbonic acid diester in the polycarbonate resin About 1 g of the resin sample is precisely weighed, dissolved in 5 mL of methylene chloride to make a solution, and then acetone is added so that the total amount becomes 25 mL. Was reprecipitated. Then, the treatment liquid was measured by liquid chromatography.
The equipment and conditions used are as follows.
・ Equipment: Shimadzu Corporation System controller: CBM-20A
Pump: LC-10AD
Column oven: CTO-10ASvp
Detector: SPD-M20A
Analytical column: Cadenza CD-18 4.6 mmφ x 250 mm
Oven temperature: 60 ° C
-Detection wavelength: 220 nm
-Eluent: Solution A: 0.1% aqueous phosphoric acid solution, Solution B: acetonitrile A / B = 50/50 (vol%) to A / B = 0/100 (vol%) in 10 minutes, gradient, A / Hold for 5 minutes at B = 0/100 (vol%) ・ Flow rate: 1 mL / min
・ Sample injection amount: 10 μL
The content of each compound in the resin was calculated by preparing a solution in which the concentration was changed for each compound, measuring under the same conditions as the above liquid chromatography to prepare a calibration curve, and using the absolute calibration curve method. ..

(5) Molding of unstretched film Resin pellets that have been vacuum dried at 90 ° C for 5 hours or more are subjected to a single-screw extruder manufactured by Isuzu Kakoki Co., Ltd. (screw diameter 25 mm, cylinder set temperature: 220 ° C to 260 ° C). It was extruded from a T-die (width 200 mm, set temperature: 200 to 260 ° C.). The extruded film was rolled with a winder while being cooled by a chill roll (set temperature: 120 to 170 ° C.) to prepare an unstretched film having a film thickness of 100 μm. The set temperature was adjusted within the range of the set temperature according to the glass transition temperature and the melt viscosity of the resin to be molded.

(6) Measurement of Refractive Index A rectangular test piece having a length of 40 mm and a width of 8 mm was cut out from the unstretched film prepared by the above method and used as a measurement sample. Using an interference filter of a wavelength 589 nm (sodium d line), a refractive index was measured _{(n D)} by Co. Atago manufactured multi-wavelength Abbe refractometer DR-M4 / 1550. The measurement was carried out at 20 ° C. using monobromonaphthalene as the interface liquid.

(7) Measurement of Total Light Transmittance The total light transmittance of the unstretched film produced by the above method was measured using a turbidity meter COH400 manufactured by Nippon Denshoku Kogyo Co., Ltd. A film having a high total light transmittance is excellent in terms of transparency.

(8) Measurement of photoelasticity coefficient A device that combines a birefringence measuring device consisting of a He-Ne laser, a polarizer, a compensator, an analyzer, and a photodetector and a viscoelastic measuring device (DVE-3 manufactured by Leology). (For details, refer to Journal of the Japanese Society of Leology, Vol. 19, p93-97 (1991)). A resin having a low photoelastic coefficient has little influence on the optical characteristics of the shape change of the film due to a temperature change or a humidity change, and is excellent in terms of performance stability to the environment.

A sample having a width of 5 mm and a length of 20 mm was cut out from the unstretched film produced by the above method, fixed to a viscoelasticity measuring device, and the storage elastic modulus E'was measured at a room temperature of 25 ° C. at a frequency of 96 Hz. At the same time, the emitted laser light is passed through a polarizer, a sample, a compensator, and an analyzer in this order, picked up by a photodetector (photon), and passed through a lock-in amplifier with respect to the amplitude and distortion of a waveform with an angular frequency of ω or 2ω. The phase difference was obtained, and the strain optical coefficient O'was obtained. At this time, the directions of the polarizer and the analyzer were adjusted so as to be orthogonal to each other and to form an angle of π / 4 with respect to the extension direction of the sample. The photoelastic coefficient C was obtained from the following equation using the storage elastic modulus E'and the strain optical coefficient O'.
C = O'/ E'

(9) Measurement of Birefringence (Δn) and Wavelength Dispersion (R450 / R550) A film piece having a width of 50 mm and a length of 125 mm was cut out from the unstretched film produced by the above method. Using a batch type biaxial stretching device (biaxial stretching device BIX-277-AL manufactured by Island Industry Co., Ltd.), the glass transition temperature of the resin + 15 ° C. stretching temperature, 300% / min stretching rate, and 1.5 times. The free-end uniaxial stretching of the film piece was carried out at a stretching ratio to obtain a retardation film. The central portion of the stretched film obtained by the above method is cut out to a width of 4 cm and a length of 4 cm, and the measurement wavelengths 450, 500, 550, 590 are measured using the phase difference measuring device KOBRA-WPR manufactured by Oji Measuring Instruments Co., Ltd. The phase difference was measured at 630 nm, and the wavelength dispersibility was measured. The wavelength dispersibility was shown by the ratio of the phase difference R450 to R550 (R450 / R550) measured at 450 nm and 550 nm. When R450 / R550 is larger than 1, the wavelength dispersion is positive, and when it is less than 1, the wavelength dispersion is inverse. When used as a 1/4 wave plate, the ideal value of R450 / R550 is 0.818 (450/550 = 0.818).

Further, the birefringence Δn was obtained from the retardation R550 at 550 nm and the film thickness of the stretched film from the following equation.
Birefringence = R550 [nm] / (film thickness [mm] × ¹⁰ 6)
In this measurement, if Δn has a positive value, it can be used as a retardation film.

[Example of Monomer Synthesis]
<Synthesis example 1>
DL-2, 3: 5,6-di-O-cyclohexylidene-myo-inositol (hereinafter abbreviated as "DCMI")
After nitrogen substitution of a 500 mL reaction vessel equipped with a Dimroth condenser, 30 g (167 mmol) of myo-inositol, 200 mL of DMF, 863 mg of p-toluenesulfonic acid monohydrate, and 75 mL of dimethoxycyclohexane were added, and the mixture was stirred at 100 ° C. for 3 hours. After cooling to 40 ° C., 2.5 mL of triethylamine was added, and DMF as a reaction solvent was distilled off under reduced pressure. Then, 250 mL of ethyl acetate was added, and the solution was separated with 300 mL of a 5% sodium carbonate aqueous solution, and then washed once with 300 mL of ion-exchanged water. The obtained organic phase was distilled off under reduced pressure, crystallization was carried out with 50 mL of ethyl acetate / 70 mL of n-hexane, and the obtained white precipitate was filtered. Then, crystallization was performed again with 50 mL of ethyl acetate / 70 mL of n-hexane. The obtained solid was vacuum dried at 60 ° C. for 5 hours to obtain 9.8 g (yield 17.2%) of DCMI, which is the target compound.

[Synthesis Example 2]
Bis [9- (2-phenoxycarbonylethyl) fluorene-9-yl] methane (hereinafter abbreviated as "BPFM")
BPFM was synthesized by the method described in WO2014-061677.

[Polycarbonate resin synthesis example and characteristic evaluation]
The abbreviations and the like of the compounds used in the following examples and comparative examples are as follows.
-DCMI: DL-2, 3: 5,6-di-O-cyclohexylidene-myo-inositol-ISB: Isosorbide (manufactured by Rocket Foil, trade name: POLYSORB)
CHDM: 1,4-Cyclohexanedimethanol (cis, trans mixture, manufactured by SK Chemical Co., Ltd.)
・ BPA: 2,2-bis [4-hydroxyphenyl] propane (manufactured by Mitsubishi Chemical Corporation)
-BHEPF: 9,9-bis [4- (2-hydroxyethoxy) phenyl] -fluorene (manufactured by Osaka Gas Chemical Co., Ltd.)
・ BisZ: 1,1-bis (4-hydroxyphenyl) cyclohexane (manufactured by Honshu Chemical Industry Co., Ltd.)
-BPFM: Bis [9- (2-phenoxycarbonylethyl) fluorene-9-yl] Methane-DPC: Diphenyl carbonate (manufactured by Mitsubishi Chemical Corporation)

The structural formula of each raw material compound is shown below.

[Example 1]
DCMI 18.58 parts by weight (0.055 mol), ISB 42.45 parts by weight (0.2908 mol), CHDM 25.42 parts by weight (0.176 mol), DPC 112.79 parts by weight (0.527 mol), and catalyst As a result, 4.59 × 10 ^-4 parts by weight (2.61 × ^10-6 mol) of calcium acetate monohydrate was charged into the reactor, and the inside of the reactor was replaced with nitrogen under reduced pressure. The raw material was dissolved with stirring at 150 ° C. for about 10 minutes in a nitrogen atmosphere. As the first step of the reaction, the temperature was raised to 220 ° C. over 30 minutes, and the reaction was carried out at normal pressure for 60 minutes. Then, the pressure was reduced from normal pressure to 13.3 kPa over 90 minutes, held at 13.3 kPa for 30 minutes, and the generated phenol was extracted from the reaction system. Then, as the second step of the reaction, the heat medium temperature was raised to 240 ° C. over 15 minutes, the pressure was reduced to 0.10 kPa or less over 15 minutes, and the generated phenol was extracted from the reaction system. After reaching a predetermined stirring torque, the pressure was restored to normal pressure with nitrogen to stop the reaction, the produced polycarbonate resin was extruded into water, and the strands were cut to obtain pellets. The above-mentioned various evaluations were carried out using the obtained polycarbonate resin pellets. The evaluation results are shown in Table 1.

The wavelength dispersion of this polycarbonate resin showed flat characteristics. Compared with Comparative Example 1, it was possible to improve the heat resistance (glass transition temperature) at the same time while having a low refractive index, a low photoelastic coefficient, and a high total light transmittance.

<Reference example 1>
When the polymerization reaction was carried out in the same manner as in Example 1 except that the final polymerization temperature was changed to 270 ° C., the resin was wound around the stirring shaft at the end of the reaction, and the molten resin could not be extracted. When methylene chloride was added to the resin collected in a small amount, it was found that an insoluble component was generated and the polymer was gelled. It is considered that the structures (1) to (3) of the present invention are decomposed to form a crosslinked component when the reaction is carried out at an excessively high temperature.

<Comparative example 1>
ISB 42.45 parts by weight (0.290 mol), BPA 17.96 parts by weight (0.079 mol), CHDM 25.42 parts by weight (0.176 mol), DPC 119.17 parts by weight (0.556 mol), and catalyst The polymerization reaction was carried out in the same manner as in Example 1 except that 9.61 × 10 ^-4 parts by weight (5.45 × 10 ^-6 mol) of calcium acetate monohydrate was used as a mixture to obtain pellets of polycarbonate resin. The above-mentioned various evaluations were carried out using the obtained polycarbonate resin pellets. The evaluation results are shown in Table 1.

<Example 2>
DCMI 10.06 parts by weight (0.030 mol), ISB 60.17 parts by weight (0.412 mol), BPFM 27.49 parts by weight (0.043 mol), DPC 85.34 parts by weight (0.398 mol), and catalyst As a result, 1.55 × 10 ^-3 parts by weight (8.83 × 10 ^-6 mol) of calcium acetate monohydrate was used, and the polymerization reaction was carried out in the same manner as in Example 1 except that the final polymerization temperature was 250 ° C. Pellets of polycarbonate resin were obtained. The above-mentioned various evaluations were carried out using the obtained polycarbonate resin pellets. The evaluation results are shown in Table 2.

The wavelength dispersion of this polycarbonate resin showed reverse wavelength dispersion. Compared with Comparative Examples 2 and 3, the heat resistance (glass transition temperature) could be improved at the same time while having a low refractive index, a low photoelastic coefficient, and a high total light transmittance.

<Comparative example 2>
ISB 64.27 parts by weight (0.440 mol), BPFM 36.51 parts by weight (0.057 mol), DPC 81.52 parts by weight (0.381 mol), and calcium acetate monohydrate 7.75 × 10 as catalyst ^A polymerization reaction was carried out in the same manner as in Example 2 except that ^-4 parts by weight (4.40 × 10 ^-6 mol) was used to obtain pellets of polyester carbonate resin. The above-mentioned various evaluations were performed using the obtained pellets of the polyester carbonate resin. The evaluation results are shown in Table 2.

<Comparative example 3>
ISB 45.42 parts by weight (0.311 mol), BPFM 36.65 parts by weight (0.057 mol), BisZ 20.15 parts by weight (0.075 mol), DPC 70.41 parts by weight (0.329 mol), and catalyst The polymerization reaction was carried out in the same manner as in Example 2 except that 6.80 × 10 ^-4 parts by weight (3.86 × 10 ^-6 mol) of calcium acetate monohydrate was used as a mixture to obtain pellets of polyester carbonate resin. .. The above-mentioned various evaluations were performed using the obtained pellets of the polyester carbonate resin. The evaluation results are shown in Table 2.

<Example 3>
DCMI 9.29 parts by weight (0.027 mol), ISB 22.92 parts by weight (0.157 mol), BHEPF 59.47 parts by weight (0.136 mol), DPC 68.50 parts by weight (0.320 mol), and catalyst The polymerization reaction was carried out in the same manner as in Example 2 except that 1.69 × 10 ^-3 parts by weight (9.59 × 10 ^-6 mol) of calcium acetate monohydrate was used as a polycarbonate resin pellet. The above-mentioned various evaluations were carried out using the obtained polycarbonate resin pellets. The evaluation results are shown in Table 2.

The wavelength dispersion of this polycarbonate resin showed reverse wavelength dispersion. Compared with Comparative Examples 4 and 5, the heat resistance (glass transition temperature) could be improved at the same time while having a low refractive index, a low photoelastic coefficient, and a high total light transmittance.

<Comparative example 4>
ISB 31.41 parts by weight (0.215 mol), BHEPF 59.47 parts by weight (0.136 mol), DPC 75.85 (0.354 mol), and calcium acetate monohydrate 1.24 × 10 ^-3 as a catalyst. A polymerization reaction was carried out in the same manner as in Example 2 except that parts by weight (7.01 × ^10-6 mol) were used to obtain pellets of polycarbonate resin. The above-mentioned various evaluations were carried out using the obtained polycarbonate resin pellets. The evaluation results are shown in Table 2.

<Comparative example 5>
BHEPF 80.49 parts by mass (0.184 mol), BPA 13.23 parts by mass (0.058 mol), DPC 53.29 parts by mass (0.249 mol), and calcium acetate monohydrate 2.13 × 10 as a catalyst ^{Using -3} parts by mass (1.21 × ^10-5 mol), the polymerization reaction was carried out in the same manner as in Example 2 except that the final polymerization temperature was set to 260 ° C. to obtain pellets of polycarbonate resin. The above-mentioned various evaluations were carried out using the obtained polycarbonate resin pellets. The evaluation results are shown in Table 2.

Claims (15)

A polycarbonate resin containing at least a structural unit represented by any of the following formulas (1) to (3) and a structural unit represented by the following formula (5).
When the total weight of all the structural units constituting the resin and the linking group is 100% by weight, the structural unit represented by any of the following formulas (1) to (3) is 1% by weight or more. Contains 70% by weight or less and 1% by weight or more and 70% by weight or less of the structural unit represented by the following formula (5).
The value of the wavelength dispersion (R450 / R550), which is the ratio of the phase difference (R450) at a wavelength of 450 nm and the phase difference (R550) at a wavelength of 550 nm, of the stretched film made from the resin is 0.50 or more, 1.03. The following polycarbonate resin.

(In the above formulas (1) to (3), R ^{1 to} R ⁴ independently represent organic groups having 1 to 30 carbon atoms, and R ¹ and R ² and R ³ and R ⁴ are acetals of each other. A ring is formed by the bond. These organic groups may have any substituents.)

The polycarbonate resin according to claim 1, wherein the cyclohexane ring in the formulas (1) to (3) is an inositol residue derived from myo-inositol. The polycarbonate resin according to claim 1 or 2, which contains at least a structural unit represented by the following formula (4).

The polycarbonate resin according to any one of claims 1 to 3, wherein the glass transition temperature is 100 ° C. or higher and 180 ° C. or lower. When the total weight of all the structural units constituting the resin and the weight of the linking group is 100% by weight, at least one structural unit selected from the following formulas (6) to ( 7 ) is 1% by weight or more, 70. The polycarbonate resin according to any one of claims 1 to 4, which contains less than% by weight.

(In the above formula (6), R ^{5 to} R ⁸ are independently hydrogen atoms, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 6 to 20 carbon atoms, respectively. Alternatively, it represents a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and X is a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 6 to 20 carbon atoms, or , Substituent or unsubstituted, represents an arylene group having 6 to 20 carbon atoms. M and n are independently integers of 0 to 5.)

(In the formula (7 ) , R ^{9 to} R ¹¹ are alkylene groups having 1 to 4 carbon atoms which may independently have a direct bond and a substituent, and R ^{12 to} R ¹⁷ are independent of each other. May have a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an aryl group having 4 to 10 carbon atoms which may have a substituent, and a substituent. It has an acyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms which may have a substituent, an aryloxy group having 1 to 10 carbon atoms which may have a substituent, and a substituent. It has an acyloxy group having 1 to 10 carbon atoms, an amino group which may have a substituent, a vinyl group having 1 to 10 carbon atoms which may have a substituent, and a substituent. good ethynyl group having 1 to 10 carbon atoms, a sulfur atom having a substituent group, the silicon atom having a substituent group, a halogen atom, a nitro group, or a cyano group. However, at least adjacent ones of R ¹² to R ¹⁷ The two groups may be bonded to each other to form a ring.) When the total weight of all the structural units constituting the resin and the weights of the linking groups is 100% by weight, the aromatic structural units other than the structural units represented by the above formulas (6) to ( 7 ) are 5 weights. The polycarbonate resin according to claim 5, which contains less than or equal to%. When the total weight of all the structural units constituting the resin and the weight of the linking group is 100% by weight, at least one structural unit selected from the following formula (8) is contained in an amount of 1% by weight or more and 70% by weight or less. The polycarbonate resin according to any one of claims 1 to 4, which is a polyester carbonate resin.

(In equation (8), R ⁹ ~ R ¹¹ Is an alkylene group having 1 to 4 carbon atoms which may have a direct bond and a substituent, respectively, and R ¹² ~ R ¹⁷ Each independently has a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an aryl group having 4 to 10 carbon atoms which may have a substituent, and a substituent. An acyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms which may have a substituent, an aryloxy group having 1 to 10 carbon atoms which may have a substituent, and the like. Aryloxy groups having 1 to 10 carbon atoms which may have a substituent, amino groups which may have a substituent, vinyl groups having 1 to 10 carbon atoms which may have a substituent, and substituents. It is an ethynyl group having 1 to 10 carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group. However, R ¹² ~ R ¹⁷ Of these, at least two adjacent groups may be bonded to each other to form a ring. ) When the total weight of all the structural units constituting the resin and the linking group is 100% by weight, it contains 5% by weight or less of aromatic structural units other than the structural unit represented by the above formula (8). The polycarbonate resin according to claim 7. From aliphatic dihydroxy compounds, alicyclic dihydroxy compounds, dihydroxy compounds containing acetal rings, and oxyalkylene glycol when the total weight of all structural units and linking groups constituting the resin is 100% by weight. The polycarbonate resin according to any one of claims 1 to 8 , which contains 0.1% by weight or more and 50% by weight or less of a structural unit derived from at least one selected compound. The polycarbonate resin according to any one of claims 1 to 9 , wherein the melt viscosity at a measurement temperature of 240 ° C. and a shear rate of 91.2 sec ^-1 is 1000 Pa · s or more and 7000 Pa · s or less. Claims 1 to 10 in which the residual amount of carbonic acid diester in the resin is 1 wt ppm or more and 300 wt ppm or less, and the content of the monohydroxy compound derived from the carbonic acid diester is 1 wt ppm or more and 1000 wt ppm or less. The polycarbonate resin according to any one of the above items. The method for producing a polycarbonate resin according to any one of claims 1 to 11 by a melt polymerization reaction, wherein the maximum temperature of the melt polymerization reaction is 200 ° C. or higher and 260 ° C. or lower. Resin manufacturing method. A transparent film obtained by molding the polycarbonate resin according to any one of claims 1 to 11 . The method for producing a transparent film according to claim 13 , wherein the polycarbonate resin according to any one of claims 1 to 9 is molded by a melt film forming method at a molding temperature of 280 ° C. or lower. .. A retardation film which is a unidirectional or bidirectional stretched film of the transparent film according to claim 13 .