WO2023074576A1

WO2023074576A1 - Polycarbonate resin

Info

Publication number: WO2023074576A1
Application number: PCT/JP2022/039329
Authority: WO
Inventors: 昂志中村; 佳史中村; 寛幸林
Original assignee: 三菱ケミカル株式会社
Priority date: 2021-10-25
Filing date: 2022-10-21
Publication date: 2023-05-04
Also published as: CN117980375A; TW202334276A

Abstract

The present invention relates to: a polycarbonate resin containing a structural unit (A), a structural unit (B), and a structural unit (C); a molded article obtained using the polycarbonate resin; a film; a retardation film; and a method for producing a transparent film. Structural unit (A) is represented by formula (1) and/or formula (2). Structural unit (B) is represented by formula (3). Structural unit (C) is derived from a dihydroxy compound having an acetal ring structure.　[Formula 1] [Formula 2] [Formula 3]

Description

Polycarbonate resin

The present disclosure relates to a polycarbonate resin, a polycarbonate resin molded article, a film, a method for producing a transparent film, and a retardation film.

Demand is increasing for transparent resins used for optical applications such as molded products, optical lenses, optical films, and optical recording media typified by the front panels of televisions and smartphones. Among them, the spread of organic EL displays is remarkable, and various optical films have been developed for the purpose of improving display quality such as improving contrast and coloring, widening the viewing angle, and preventing external light reflection.

A quarter-wave plate is used in organic EL displays to prevent reflection of external light. The retardation film used in the quarter-wave plate suppresses coloring and enables clear black display, so it is possible to obtain ideal retardation characteristics at each wavelength in the visible region, and broadband wavelength dispersion. is required. As an equivalent to this, for example, Patent Document 1 discloses a polycarbonate copolymer having an oligofluorene structural unit and a retardation film using the same. A retardation film exhibiting properties is disclosed. Further, in Patent Document 2, a structure derived from 6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane (hereinafter sometimes abbreviated as SBI) A polycarbonate copolymer containing units and a retardation film using the same are disclosed, which are excellent in heat resistance and optical properties.

JP 2015-212368 A JP 2019-178340 A

In recent years, organic EL displays have come to be used as in-vehicle displays, and the retardation film used in organic EL displays must function without problems even in harsher usage environments than before. is being sought. Specifically, for example, organic EL displays for automobiles are used under high temperature and high humidity, so the retardation film is required to have higher resistance to heat and humidity than conventional ones.
Although some of the polycarbonate copolymers described in Patent Documents 1 and 2 satisfy the required optical properties, they have insufficient moisture and heat resistance, and can be used under higher temperature conditions and higher humidity atmospheres than before. However, the optical characteristics were insufficient. There is also room for improvement in mechanical properties such as toughness and melt processability.

The present disclosure has been made in view of such a background, with excellent optical properties, moist heat resistance and mechanical properties, polycarbonate resin with high melt processability, molded articles obtained using it, films, retardation films, and to provide a method for producing a transparent film.

A first aspect of the present disclosure is a structural unit (A) represented by the following formula (1) and/or the following formula (2),
A structural unit (B) represented by the following formula (3);
and a structural unit (C) derived from a dihydroxy compound having an acetal ring structure.

However, in formula (1), R ¹ to R ³ each independently represent a direct bond or a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms. In formula (1), R ⁴ to R ⁹ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a substituted or unsubstituted acyl group having 2 to 10 carbon atoms, substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms, substituted or unsubstituted amino group, substitution or an unsubstituted vinyl group having 2 to 10 carbon atoms, a substituted or unsubstituted ethynyl group having 2 to 10 carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or cyano represents a group. In formula (1), R ⁴ to R ⁹ may be the same or different, and at least two adjacent groups among R ⁴ to R ⁹ are bonded to each other to form a ring; good too.

However, in formula (2), R ¹ to R ³ each independently represent a direct bond or a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms. In formula (2), R ⁴ to R ⁹ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a substituted or unsubstituted acyl group having 2 to 10 carbon atoms, substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms, substituted or unsubstituted amino group, substitution or an unsubstituted vinyl group having 2 to 10 carbon atoms, a substituted or unsubstituted ethynyl group having 2 to 10 carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or cyano represents a group. In formula (2), R ⁴ to R ⁹ may be the same or different, and at least two adjacent groups among R ⁴ to R ⁹ are bonded to each other to form a ring; good too.

However, in formula (3), R ¹⁰ to R ¹⁷ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms. represents In formula (3), X ¹ represents a direct bond or a divalent hydrocarbon group having 1 to 20 carbon atoms.

A second aspect of the present disclosure resides in a polycarbonate resin molded article composed of the above polycarbonate resin.

A third aspect of the present disclosure is a film composed of the polycarbonate resin.

A fourth aspect of the present disclosure is a retardation film made of the above film.

A fifth aspect of the present disclosure is a circularly polarizing plate including the retardation film.

A sixth aspect of the present disclosure resides in an image display device including the above-described circle changing plate.

A seventh aspect of the present disclosure is a method for producing a transparent film by molding the polycarbonate resin by a melt film-forming method,
A method for producing a transparent film, wherein the polycarbonate resin is molded at a molding temperature of 280° C. or less.

An eighth aspect of the present disclosure is a structural unit (A) represented by the above formula (1) and/or the above formula (2),
and a structural unit (B) represented by the above formula (3),
a glass transition temperature of 120° C. or higher and 160° C. or lower;
The polycarbonate resin has a water absorption of 1.4% or less.

As described above, the polycarbonate resin has a structural unit having a specific oligofluorene structure and a specific copolymer component. Therefore, the polycarbonate resin has excellent optical properties and high moisture and heat resistance. In addition, polycarbonate resins are excellent in mechanical properties such as toughness and in melt processability.
In addition, polycarbonate resin molded articles, films, retardation films, and circular polarizers composed of the polycarbonate resin have high moisture and heat resistance, and are excellent in optical properties and mechanical properties. Further, since the image display device has the circular polarizing plate, it can be suitably used for a flexible display, an in-vehicle display that requires high moisture and heat resistance, and the like.

In the above manufacturing method, the above polycarbonate resin is molded by a melt film forming method at a molding temperature of 280°C or less. As a result, a transparent film having excellent mechanical properties such as toughness and optical properties and having high resistance to moist heat is produced.

Embodiments of the present invention will be described in detail below. is not limited to the contents of As used herein, the term “structural unit” refers to a partial structure sandwiched between adjacent linking groups in a polymer, a polymerizable group present at the terminal portion of the polymer, and the polymerizable reactive group. It refers to a partial structure sandwiched between adjacent linking groups. In addition, when the expression "~" is used in this specification, it is used in the sense of including the numerical values or physical values described before and after it. Numerical values or physical values described as the upper limit and the lower limit are used in the sense of including those values. "%" means "% by weight" unless otherwise specified. Further, "parts by weight" and "parts by mass", and "% by weight" and "% by mass" are substantially synonymous.

In the present disclosure, polycarbonate resin is a concept that includes not only polycarbonate resin but also polyester carbonate resin. A polyester carbonate resin is a polymer containing a portion in which the structural units constituting the polymer are linked not only by carbonate bonds but also by ester bonds.

In this specification, when "~" is used to express numerical values or physical property values before and after it, it is used to include the values before and after it.

A polycarbonate resin is composed of at least a structural unit (A), a structural unit (B) and a structural unit (C), and has a large number of these structural units in the polymer chain. Polycarbonate resin is, for example, a random copolymer. Structural unit (A) is represented by the following formula (1) and/or the following formula (2). That is, the polycarbonate resin has a structural unit represented by the formula (1) and/or a structural unit represented by the formula (2) as the structural unit (A). Structural unit (B) is represented by the following formula (3). Structural unit (C) is a structural unit derived from a dihydroxy compound having an acetal ring structure. An acetal ring structure is also called a cyclic acetal structure.

In formulas (1) and (2), R ¹ to R ³ are each independently a direct bond, a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms. R ⁴ to R ⁹ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, or a substituted or unsubstituted 2 carbon atoms -10 acyl groups, substituted or unsubstituted alkoxy groups having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy groups having 6 to 10 carbon atoms, substituted or unsubstituted amino groups, substituted or unsubstituted carbon atoms 2 to 10 vinyl groups, substituted or unsubstituted ethynyl groups having 2 to 10 carbon atoms, substituted sulfur atoms, substituted silicon atoms, halogen atoms, nitro groups, or cyano groups. R ⁴ to R ⁹ may be the same or different, and at least two adjacent groups among R ⁴ to R ⁹ may combine to form a ring.

In formula (3), R ¹⁰ to R ¹⁷ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms. show. X ¹ represents a direct bond or a divalent hydrocarbon group having 1 to 20 carbon atoms.

[Structure and Raw Materials of Polycarbonate Resin]
<Oligofluorene structural unit>
The polycarbonate resin contains structural units (A) composed of structural units represented by the following formula (1) and/or structural units represented by the following formula (2). Hereinafter, the structural unit may be referred to as "oligofluorene structural unit".

In formulas (1) and (2), R ¹ to R ³ each independently represent a direct bond or a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms. R ⁴ to R ⁹ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, or a substituted or unsubstituted 2 carbon atoms ~10 acyl group, substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms, substituted or unsubstituted amino group, substituted or unsubstituted carbon number 2 to 10 vinyl groups, substituted or unsubstituted ethynyl groups having 2 to 10 carbon atoms, substituted sulfur atoms, substituted silicon atoms, halogen atoms, nitro groups, or cyano groups. However, R ⁴ to R ⁹ may be the same or different, and at least two adjacent groups among R ⁴ to R ⁹ may combine with each other to form a ring. From the viewpoint that the fluorene rings in the polymer are likely to be oriented perpendicularly to the main chain direction and exhibit stronger reverse wavelength dispersion, the polycarbonate resin should contain a structural unit represented by formula (2). is preferred.

As R ¹ and R ² , for example, the following alkylene groups can be employed. Specifically, linear alkylene groups 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, Examples thereof include branched alkylene groups such as 2-dimethylpropylene group and 3-methylpropylene group. Here, the position of the branched chain in R ¹ and R ² is indicated by the number assigned so that the carbon on the fluorene ring side is at the 1st position. R ¹ and R ² are preferably ethylene groups from the viewpoint that the fluorene rings in the polymer are easily oriented perpendicularly to the main chain direction and exhibit stronger reverse wavelength dispersion.

The selection of ^R1 and ^R2 can be related to the development of inverse dispersion wavelength dependence. Polycarbonate resin exhibits the strongest reverse dispersion wavelength dependence in a state in which the fluorene rings are oriented perpendicular to the main chain direction (stretching direction). In order to bring the orientation state of the fluorene rings closer to this state and to express strong reverse dispersion wavelength dependence, it is possible to adopt R ¹ and R ² having 2 to 3 carbon atoms in the main chain of the alkylene group. preferable. When the number of carbon atoms is 1, there are cases where, unexpectedly, reverse dispersion wavelength dependence is not exhibited. This is because, for example, the steric hindrance of the carbonate group and/or the ester group, which are the linking groups of the oligofluorene structural units, fixes the orientation of the fluorene ring in a direction that is not perpendicular to the main chain direction. it is conceivable that. On the other hand, if the number of carbon atoms is too large, the fixation of the orientation of the fluorene ring is weakened, which may result in insufficient reverse dispersion wavelength dependence. Furthermore, the heat resistance of the polycarbonate resin may be lowered.

As R ³ , for example, the following alkylene groups can be employed. Specifically, linear alkylene groups 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, Examples include branched alkylene groups such as 2-dimethylpropylene group and 3-methylpropylene group. R ³ preferably has 1 to 2 carbon atoms on the main chain of the alkylene group, more preferably 1 carbon atom. If the number of carbon atoms on the main chain is too large, the fixation of the fluorene ring is weakened as in the case of ^R1 and ^R2 , resulting in a decrease in reverse dispersion wavelength dependence, an increase in the photoelastic coefficient, a decrease in heat resistance, etc. may invite. On the other hand, the smaller the number of carbon atoms on the main chain, the better the optical properties and heat resistance.

Substituents for R ¹ to R ³ include, for example, a halogen atom (specifically, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom); an alkoxy group having 1 to 10 carbon atoms such as a methoxy group and an ethoxy group ; acyl group having 1 to 10 carbon atoms such as acetyl group and benzoyl group; acylamino group having 1 to 10 carbon atoms such as acetamide group and benzoylamide group; nitro group; cyano group; -10 aryl groups are included. One to three hydrogen atoms in the aryl group may be substituted with the halogen atom, alkoxy group, acyl group, acylamino group, nitro group, cyano group or the like described above.

As the substituted or unsubstituted alkyl group for R ⁴ to R ⁹ , for example, the following alkyl groups can be employed. Specifically, linear alkyl groups such as methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl, n-decyl; isopropyl group, 2-methylpropyl group , 2,2-dimethylpropyl group and 2-ethylhexyl group; and cyclic alkyl groups such as cyclopropyl group, cyclopentyl group, cyclohexyl group and cyclooctyl group. The number of carbon atoms in the alkyl group is preferably 4 or less, more preferably 2 or less. When the number of carbon atoms is within this range, steric hindrance between fluorene rings is less likely to occur, and desired optical properties derived from the fluorene rings are likely to be obtained. Substituents for the alkyl group include the substituents described above for R ¹ to R ³ .

As the substituted or unsubstituted aryl group for R ⁴ to R ⁹ , for example, the following aryl groups can be employed. Specific examples include aryl groups such as phenyl group, 1-naphthyl group and 2-naphthyl group; heteroaryl groups such as 2-pyridyl group, 2-thienyl group and 2-furyl group. The number of carbon atoms in the aryl group is preferably 8 or less, more preferably 7 or less. When the number of carbon atoms is within this range, steric hindrance between fluorene rings is less likely to occur, and desired optical properties derived from the fluorene rings are likely to be obtained. Substituents for the aryl group include the substituents described above for R ¹ to R ³ .

As the substituted or unsubstituted acyl group for R ⁴ to R ⁹ , for example, the following acyl groups can be employed. Specifically, aliphatic acyl groups such as formyl group, acetyl group, propionyl group, 2-methylpropionyl group, 2,2-dimethylpropionyl group, and 2-ethylhexanoyl group; benzoyl group, 1-naphthylcarbonyl group, Aromatic acyl groups such as 2-naphthylcarbonyl group and 2-furylcarbonyl group can be mentioned. The number of carbon atoms in the acyl group is preferably 4 or less, more preferably 2 or less. When the number of carbon atoms is within this range, steric hindrance between fluorene rings is less likely to occur, and desired optical properties derived from the fluorene rings are likely to be obtained. Substituents for the acyl group include the substituents described above for R ¹ to R ³ .

As the substituted or unsubstituted alkoxy group or aryloxy group for R ⁴ to R ⁹ , for example, the following can be employed. Specific examples include a methoxy group, an ethoxy group, an isopropoxy group, a tert-butoxy group, a trifluoromethoxy group, and a phenoxy group. The number of carbon atoms in the alkoxy group or aryloxy group is preferably 4 or less, more preferably 2 or less. When the number of carbon atoms is within this range, steric hindrance between fluorene rings is less likely to occur, and desired optical properties derived from the fluorene rings are likely to be obtained. Substituents for the alkoxy group or aryloxy group include the substituents described above for R ¹ to R ³ .

As the substituted or unsubstituted amino group for R ⁴ to R ⁹ , for example, the following amino groups can be employed. Specifically, an amino group; N-methylamino group, N,N-dimethylamino group, N-ethylamino group, N,N-diethylamino group, N,N-methylethylamino group, N-propylamino group, N,N-dipropylamino group, N-isopropylamino group, N,N-diisopropylamino group and other aliphatic amino groups; N-phenylamino group, N,N-diphenylamino group and other aromatic amino groups; formamide acylamino groups such as radicals, acetamide group, decanoylamide group, benzoylamide group and chloroacetamide group; alkoxycarbonylamino groups such as benzyloxycarbonylamino group and tert-butyloxycarbonylamino group. The amino group is preferably an N,N-dimethylamino group, an N-ethylamino group, or an N,N-diethylamino group, more preferably an N,N-dimethylamino group. In this case, since the amino group does not have protons with high acidity and the molecular weight of the amino group is small, the fluorene ratio can be increased. Therefore, in addition to improving the thermal stability, it is possible to reduce the amount of the monomer having an oligofluorene structural unit.

Examples of substituted or unsubstituted vinyl or ethynyl groups for R ⁴ to R ⁹ include the following. Specifically, vinyl group, 2-methylvinyl group, 2,2-dimethylvinyl group, 2-phenylvinyl group, 2-acetylvinyl group, ethynyl group, methylethynyl group, tert-butylethynyl group, phenylethynyl group , an acetylethynyl group, and a trimethylsilylethynyl group. The number of carbon atoms in the vinyl group or ethynyl group is preferably 4 or less. When the number of carbon atoms is within this range, steric hindrance between fluorene rings is less likely to occur, and desired optical properties derived from the fluorene rings are likely to be obtained. In addition, the lengthening of the conjugated system of the fluorene ring makes it easier to obtain stronger reverse dispersion wavelength dependence.

As the substituted sulfur atom for R ⁴ to R ⁹ , for example, the following sulfur-containing groups can be employed. Specifically, sulfo group; alkylsulfonyl group such as methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group and isopropylsulfonyl group; arylsulfonyl group such as phenylsulfonyl group and p-tolylsulfonyl group; methylsulfinyl group, ethylsulfinyl alkylsulfinyl groups such as phenylsulfinyl group and p-tolylsulfinyl group; alkylthio groups such as methylthio group and ethylthio group; arylthio groups such as phenylthio group and p-tolylthio group; Alkoxysulfonyl groups such as methoxysulfonyl group and ethoxysulfonyl group; Aryloxysulfonyl groups such as phenoxysulfonyl group; Aminosulfonyl group; N-methylaminosulfonyl group, N-ethylaminosulfonyl group, N-tert-butylaminosulfonyl group alkylsulfonyl groups such as N,N-dimethylaminosulfonyl group and N,N-diethylaminosulfonyl group; and arylaminosulfonyl groups such as N-phenylaminosulfonyl group and N,N-diphenylaminosulfonyl group. The sulfo group may form a salt with lithium, sodium, potassium, magnesium, ammonium or the like. The sulfur-containing group is preferably a methylsulfinyl group, an ethylsulfinyl group, or a phenylsulfinyl group, more preferably a methylsulfinyl group. In this case, the sulfur-containing group does not have protons with high acidity and the molecular weight of the sulfur-containing group is small, so that the fluorene ratio can be increased. Therefore, in addition to improving the thermal stability, it is possible to reduce the amount of the monomer having an oligofluorene structural unit.

As silicon atoms having substituents in R ⁴ to R ⁹ , for example, the following silyl groups can be employed. Specific examples include trialkylsilyl groups such as trimethylsilyl group and triethylsilyl group; and trialkoxysilyl groups such as trimethoxysilyl group and triethoxysilyl group. Trialkylsilyl groups are preferred. This is because it is excellent in stability and handleability.

Further, in R ⁴ to R ⁹ , for example, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom can be employed as the halogen atom. Among these, it is possible to adopt a fluorine atom, a chlorine atom, or a bromine atom from the viewpoint that it is relatively easy to introduce and has a tendency to increase the reactivity of the fluorene 9-position due to its electron-withdrawing property. Preferably, a chlorine atom or a bromine atom is more preferably employed.

Specific examples of the ring formed by binding together at least two adjacent groups among R ⁴ to R ⁹ include substituted fluorene structures shown in the following group [I]. In the following group [I], the wavy line indicates that the bond connecting the 9-position of the fluorene structure to ^R1 and ^R2 or ^R2 and ^R3 is schematically omitted.

In addition to being able to adjust the wavelength dispersion of the polycarbonate resin to a desired range, from the viewpoint of improving the mechanical properties, the structural unit (A ) is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, particularly preferably 7% by mass or more, and 10 % or more is most preferable. In addition to reducing the photoelastic coefficient of the polycarbonate resin, an improvement in the expression of the retardation is expected, and the ratio of the structural unit (A) in the resin can be reduced, thereby widening the range of molecular design. The content of the structural unit (A) is preferably 45% by mass or less, more preferably 40% by mass or less, from the viewpoint of facilitating improvement when the resin is required to be modified. It is more preferably not more than 30% by mass, and particularly preferably not more than 30% by mass. The linking group is specifically a carbonate group or an ester group present at the end of each structural unit. The content of the structural unit (A) is the total content of the structural unit represented by the formula (1) and the structural unit represented by the formula (2). , the content of the other is zero.

Methods for adjusting the ratio of oligofluorene structural units in the resin include, for example, a method of copolymerizing a monomer having an oligofluorene structural unit and another monomer, and a method of copolymerizing a resin containing an oligofluorene structural unit with another resin. A method of blending is mentioned. The content of oligofluorene structural units can be precisely controlled, high transparency can be obtained, and uniform properties can be obtained over the entire surface of the film. method is preferred.

A polycarbonate resin contains a structural unit (B) represented by the following formula (3).

In the above formula (3), R ¹⁰ to R ¹⁷ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms. show. X ¹ represents a direct bond or a divalent hydrocarbon group having 1 to 20 carbon atoms. Here, when X ¹ in formula (3) is a divalent hydrocarbon group having 1 to 20 carbon atoms, the hydrocarbon group is a substituted or unsubstituted chain alkylene group having 1 to 20 carbon atoms, a substituted or It is preferably an unsubstituted cyclic alkylene group having 6 to 20 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a fluorenylene group having 13 to 20 carbon atoms. In this case, effects such as improvement in heat resistance and reduction in water absorption can be obtained.
Examples of chain alkylene groups and cyclic alkylene groups include -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -CH(Ph)-, and -C(CH ₃ )Ph- , —CPh ₂ —, 1,2-ethylene group, 1,3-propylene group, 1,4-butylene group, 1,1-cyclopropylene group, 1,1-cyclobutylene group, 1,1-cyclopentylene group, 1,1-cyclohexylene group, 3,3,5-trimethyl-1,1-cyclohexylene group, 1,1-cyclododecylene group, 1,2-cyclopropylene group, 1,2-cyclobutylene group, 1 ,2-cyclopentylene group, 1,2-cyclohexylene group, 1,3-cyclobutylene group, 1,3-cyclopentylene group, 1,3-cyclohexylene group, 1,4-cyclohexylene group, etc. mentioned. Here, Ph is an unsubstituted phenyl group.
Arylene groups include 1,2-phenylene groups, 1,3-phenylene groups and 1,4-phenylene groups.
The fluorenylene group includes a 9,9-fluorenylene group.
Further, when X ₁ is a divalent hydrocarbon group having 1 to 20 carbon atoms, the bonding positions on the benzene ring in the above formula (3) are 2,2′-position, 2,3′-position, 2,4 It may be at the '-position, 3,3'-position, 3,4'-position or 4,4'-position, preferably 4,4'-position. In this case, mechanical properties are further improved.
On the other hand, when X ¹ is a direct bond, the biphenyl skeleton in the above formula (3) is 2,2′-biphenyl skeleton, 2,3′-biphenyl skeleton, 2,4′-biphenyl skeleton, 3,3′- A biphenyl skeleton, a 3,4'-biphenyl skeleton, or a 4,4'-biphenyl skeleton may be used, but the 4,4'-biphenyl skeleton is preferred.
From the viewpoint of further improving the heat-and-moisture resistance of the polycarbonate resin, X ₁ in formula (3) is even more preferably -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, - CH(Ph)—, —C(CH ₃ )Ph—, —CPh ₂ —, 9,9-fluorenylene group, 1,1-cyclohexylene group, 3,3,5-trimethyl-1,1-cyclohexylene group , 1,1-cyclododecylene group.
In formula (3) above, R ¹⁰ to R ¹⁷ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group.
The substituted or unsubstituted alkyl group having 1 to 20 carbon atoms may be linear, branched or cyclic, and may have a substituent such as a phenyl group. things are mentioned.
For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, cyclopentyl group, n-hexyl group, isohexyl group, cyclohexyl group, n-heptyl group, cycloheptyl group, methylcyclohexyl group, n-octyl group, cyclooctyl group, n-nonyl group, 3,3,5-trimethylcyclohexyl group, n- decyl group, cyclodecyl group, n-undecyl group, n-dodecyl group, cyclododecyl group, benzyl group, methylbenzyl group, dimethylbenzyl group, trimethylbenzyl group, naphthylmethyl group, phenethyl group, 2-phenylisopropyl group and the like. .
Examples of substituted or unsubstituted aryl groups include phenyl, o-tolyl, m-tolyl, p-tolyl, ethylphenyl, styryl, xylyl, n-propylphenyl, isopropylphenyl, A phenyl group and a naphthyl group which may have a substituent such as an alkyl group, such as a mesityl group, an ethynylphenyl group, a naphthyl group and a vinylnaphthyl group.
R ¹⁰ to R ¹⁷ are still more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, particularly preferably a hydrogen atom or a methyl group.

Examples of the dihydroxy compound from which the structural unit (B) is derived (that is, the dihydroxy compound that constitutes the structural unit (B)) include 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-(3,5-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, 4,4'-(cyclododecane-1,1-diyl)diphenol, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4'-(cyclododecane-1 Aromatic bisphenol compounds such as ,1-diyl)diphenol, 4,4'-(α-methylbenzylidene)bisphenol; 2,2-bis(4-(2-hydroxyethoxy)phenyl)propane, 2,2-bis( Dihydroxy compounds having an ether group bonded to an aromatic group such as 4-(2-hydroxypropoxy)phenyl)propane, 4,4′-bis(2-hydroxyethoxy)biphenyl; 9,9-bis(4-(2 -hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxy propoxy)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)-3-isopropylphenyl)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) dihydroxy compounds having a fluorene ring such as -3-tert-butyl-6-methylphenyl)fluorene and 9,9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene. Preferably, the dihydroxy compound from which the structural unit (B) is derived is 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4, 4'-(cyclododecane-1,1-diyl)diphenol, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4'-(cyclododecane-1,1-diyl)diphenol, 4,4'-(α-methylbenzylidene)bisphenol and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene.

Particularly suitable specific examples of the structural unit (B) are represented by the following formulas (6) to (11). Structural unit (B) preferably contains at least one selected from the group consisting of the following formulas (6) to (11), and at least one selected from the group consisting of the following formulas (8) to (11) It is more preferable to contain the following formula (8) and/or the following formula (9) is particularly preferable, and the following formula (8) is most preferable. In this case, even if the content of the structural unit (B) in the polycarbonate resin is small, the heat resistance of the resin can be improved and the water absorption can be reduced. That is, the heat resistance can be efficiently improved and the water absorption can be efficiently reduced. Furthermore, in this case, the photoelastic coefficient of the polycarbonate resin can be reduced, and the mechanical properties of the polymer are also improved.

From the viewpoint that the heat resistance of the polycarbonate resin can be increased, the water absorption rate can be reduced, and the mechanical properties can be improved, the structural unit (B) relative to the total amount of 100% by mass of all the structural units and linking groups that constitute the polycarbonate resin The content of is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, even more preferably 20% by mass or more, and 25 % by mass or more is most preferred. Further, from the viewpoint that the photoelastic coefficient of the polycarbonate resin can be reduced, the content of the structural unit (B) is preferably 50% by mass or less, more preferably 45% by mass or less, and 40% by mass. % or less, and particularly preferably 35 mass % or less.

The polycarbonate resin contains a structural unit (C) derived from a dihydroxy compound having an acetal ring structure. As the dihydroxy compound having an acetal ring structure, for example, dioxane glycol represented by the following formula (13) and/or spiroglycol represented by the formula (14) can be used.

Structural unit (C) is preferably a structural unit derived from spiroglycol represented by formula (14). In this case, the heat resistance of the polycarbonate resin can be enhanced and the photoelastic coefficient can be reduced.

From the viewpoint that the balance of physical properties such as heat resistance and optical properties can be adjusted without greatly impairing the excellent properties of the polycarbonate resin, the total amount of all structural units and linking groups constituting the polycarbonate resin is 100% by mass. The content of the structural unit (C) for the is particularly preferred. From the same viewpoint, the content of the structural unit (C) is preferably 75% by mass or less, more preferably 70% by mass or less, even more preferably 65% by mass or less, and 60% by mass or less. % by mass or less is particularly preferred.

Furthermore, the polycarbonate resin may contain a structural unit (D) derived from at least one compound selected from the group consisting of an aliphatic dihydroxy compound, an alicyclic dihydroxy compound, an oxyalkylene glycol, and a dihydroxy compound having a heterocyclic structure. . Structural unit (D) means a structural unit other than structural units (A) to (C), and does not include an acetal ring structure even if it has a heterocyclic ring structure. From the viewpoint of further improving the mechanical properties of the polycarbonate resin, the structural unit (D) is selected from the group consisting of aliphatic dihydroxy compounds, alicyclic dihydroxy compounds, and dihydroxy compounds having a heterocyclic structure other than an acetal ring structure. It is preferably a structural unit derived from at least one compound.

Examples of aliphatic dihydroxy compounds include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2 -pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5- Hexanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecane Linear aliphatic dihydroxy compounds such as diols, neopentyl glycol, 2-ethyl-1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, hydrogenated dilinoleyl glycol, hydrogenated dihydroxy Examples include branched chain aliphatic dihydroxy compounds such as rail glycol. Among these, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1 ,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol and other linear aliphatic dihydroxy compounds are available and easy to handle. preferable.

Examples of alicyclic dihydroxy compounds include the following dihydroxy compounds. Specifically, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, pentacyclopentadecanedimethanol, 2,6-decanedimethanol, 1 ,5-decalindimethanol, 2,3-decalindimethanol, 2,3-norbornanedimethanol, 2,5-norbornanedimethanol, 1,3-adamantanedimethanol, dihydroxy compounds derived from terpene compounds such as limonene 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,3-adamantanediol, hydrogenated bisphenol A, 2,2, Examples include dihydroxy compounds that are secondary alcohols or tertiary alcohols of alicyclic hydrocarbons, such as 4,4-tetramethyl-1,3-cyclobutanediol.

As oxyalkylene glycols, for example, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. can be used.

Examples of dihydroxy compounds having a heterocyclic structure include dihydroxy compounds represented by the following formula (12).

Examples of dihydroxy compounds represented by the above formula (12) include isosorbide, isomannide, and isoidet, which are related to stereoisomers. Among these dihydroxy compounds (12), isosorbide, which is abundant as a resource, is easily available, and is obtained by dehydration condensation of sorbitol produced from various starches, is easy to obtain and easy to produce. It is most preferred from the aspect of moldability. These dihydroxy compounds (12) may be used singly or in combination of two or more.

Structural unit (D) is preferably a structural unit derived from the compound of formula (12). In this case, effects such as development of high heat resistance and favorable polymerization reactivity can be obtained.

Further, from the viewpoint of easily balancing heat resistance, optical properties, mechanical properties, and polymerization reactivity, the structural unit (C) is a structural unit derived from the compound of formula (14), and the structural unit (D) is a structural unit of the formula It is preferably a structural unit derived from the compound (12). The structural unit derived from the compound represented by formula (14) is represented by the following formula (4), and the structural unit derived from the compound represented by formula (12) is represented by the following formula (5) .

At least one compound selected from the group consisting of the aliphatic dihydroxy compounds, alicyclic dihydroxy compounds, oxyalkylene glycols, and dihydroxy compounds having a heterocyclic structure includes 1,6-hexanediol, 2,2,4 ,4-tetramethyl-1,3-cyclobutanediol, 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, isosorbide, dioxane glycol and spiroglycol are preferred, and isosorbide and spiroglycol are particularly preferred. Polycarbonate resins containing structural units derived from these monomers have an even better balance of optical properties, heat resistance, mechanical properties, and the like.

From the viewpoint that the balance of physical properties such as heat resistance and optical properties can be adjusted without greatly impairing the excellent properties of the polycarbonate resin, the total amount of all structural units and linking groups constituting the polycarbonate resin is 100% by mass. The total content of the structural unit (C) and the structural unit (D) is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more , 35% by mass or more. From the same viewpoint, the total content of the structural unit (C) and the structural unit (D) is preferably 80% by mass or less, more preferably 75% by mass or less, and 70% by mass or less. More preferably, the content is particularly preferably 65% by mass or less.

<Carbonic acid diester>
The linking group of the structural unit contained in the polycarbonate resin is introduced by polymerizing a diester carbonate represented by the following formula (15).

In formula (15), R ¹⁸ and R ¹⁹ are each an optionally substituted aliphatic hydrocarbon group having 1 to 18 carbon atoms, or an optionally substituted C 6 to 10 and R ¹⁸ and R ¹⁹ may be the same or different.

R ¹⁸ and R ¹⁹ are preferably substituted or unsubstituted aromatic hydrocarbon groups, more preferably unsubstituted aromatic hydrocarbon groups. Examples of substituents for the aliphatic hydrocarbon group include ester groups, ether groups, amide groups and halogen atoms, and examples of substituents for the aromatic hydrocarbon group include alkyl groups such as methyl and ethyl. be done.

Examples of the diester carbonate represented by the formula (15) include diphenyl carbonate (hereinafter sometimes abbreviated as DPC), substituted diphenyl carbonate such as ditolyl carbonate, dimethyl carbonate, diethyl carbonate and di-tert- Dialkyl carbonates such as butyl carbonate are exemplified, but diphenyl carbonate and substituted diphenyl carbonate are preferred, and diphenyl carbonate is particularly preferred.

Carbonic acid diesters may contain impurities such as chloride ions, and these impurities may inhibit the polymerization reaction or deteriorate the hue of the resulting resin. It is preferred to use purified ones.

[Physical properties of polycarbonate resin]
The polycarbonate resin preferably has the physical properties described below.

(Glass-transition temperature)
The glass transition temperature of the polycarbonate resin is preferably 120° C. or higher, more preferably 125° C. or higher, and even more preferably 130° C. or higher. When the glass transition temperature is at least the above lower limit, sufficient heat resistance can be obtained. Also, the glass transition temperature of the polycarbonate resin is preferably 160° C. or lower, more preferably 155° C. or lower, and even more preferably 150° C. or lower. When the glass transition temperature is equal to or lower than the above upper limit, the melt processability is improved. The glass transition temperature of the polycarbonate resin can be measured by the method described in Examples. The glass transition temperature of the polycarbonate resin can be appropriately adjusted, for example, by changing the types and ratios of the structural units that constitute the resin.

(water absorption rate)
The water absorption of the polycarbonate resin is preferably 1.4% or less, more preferably 1.3% or less, still more preferably 1.2% or less, particularly preferably 1.1% or less, and most preferably 1%. .0% or less. When the water absorption is equal to or less than the above upper limit, the dimensional change rate in a moist heat environment is sufficiently reduced. Therefore, when a retardation film made of a polycarbonate resin is incorporated in a display device, for example, the change in display characteristics over time can be suppressed. The water absorption of the polycarbonate resin can be measured by the method described below. The water absorption rate of the polycarbonate resin can be appropriately adjusted, for example, by changing the type and ratio of structural units constituting the resin.

(photoelastic coefficient)
The viscosity of the polycarbonate resin is preferably 25×10 ⁻¹² Pa or less, more preferably 22×10 ⁻¹² Pa or less, still more preferably 19×10 ⁻¹² Pa or less, even more preferably 16×10 ⁻¹² Pa or less, and 15 ×10 ⁻¹² Pa or less is particularly preferable, and 14×10 ⁻¹² Pa or less is most preferable. When the photoelastic coefficient is equal to or less than the above upper limit, sufficient environmental reliability (visibility does not change depending on usage environment) can be obtained when the polycarbonate resin is used as a retardation film. This property is particularly important for large display devices, flexible displays, and when used in high-temperature and high-humidity environments.
In the polycarbonate resin, by reducing the content of the structural unit (A) represented by the formula (1) or (2) and the structural unit (B) represented by the formula (3), photoelastic It becomes possible to keep the coefficient lower.

[Conditions for manufacturing polycarbonate resin]
A polycarbonate resin can be produced by a generally used polymerization method. For example, it can be produced using a solution polymerization method or an interfacial polymerization method using phosgene or a carboxylic acid halide, or a melt polymerization method in which a reaction is performed without using a solvent. Among these production methods, the melt polymerization method is preferable because it does not use a solvent or a highly toxic compound, so that the environmental load can be reduced and the productivity is excellent.

When a solvent is used for polymerization, the solvent may remain in the polycarbonate resin, and its plasticizing effect lowers the glass transition temperature of the polycarbonate resin. obtain. Halogen-based organic solvents such as methylene chloride are often used as solvents. It can also cause corrosion of parts. Since the polycarbonate resin obtained by the melt polymerization method does not contain a solvent, it is advantageous in terms of processing steps and stabilization of product quality.

When producing a polycarbonate resin by a melt polymerization method, a monomer having the structural unit described above, a diester carbonate, 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 out of the system. At the end of the polymerization, the reaction proceeds to the target molecular weight under high temperature and high vacuum conditions. After the reaction is complete, the molten polycarbonate resin is withdrawn from the reactor. Thus, a polycarbonate resin is obtained.

In the polycondensation reaction, the reaction rate and the molecular weight of the resulting polycarbonate resin can be controlled by strictly adjusting the molar ratio of all dihydroxy compounds and all diester compounds used in the reaction. In the case of polycarbonate resin, the molar ratio of diester carbonate to all dihydroxy compounds is preferably adjusted to 0.90 to 1.10, more preferably 0.96 to 1.08, and more preferably 0.98 to 1 Adjustment to 0.06 is particularly preferred. In the case of polyester carbonate resin, the molar ratio of the total amount of carbonic acid diester and all diester compounds to all dihydroxy compounds is preferably adjusted to 0.90 to 1.10, and adjusted to 0.96 to 1.08. is more preferable, and adjusting to 0.98 to 1.06 is particularly preferable.

If the above molar ratio deviates significantly up or down, it will not be possible to produce a resin with the desired molecular weight. On the other hand, if the above molar ratio is too small, the number of terminal hydroxy groups in the produced resin increases, and the thermal stability of the resin may deteriorate. In addition, a large amount of unreacted dihydroxy compound remains in the polycarbonate resin, which may cause contamination of the molding machine and poor appearance of the molded product in the subsequent molding process. On the other hand, if the above molar ratio is too large, the speed of the transesterification reaction will decrease under the same conditions, or the residual amount of carbonic acid diesters and diester compounds in the produced polycarbonate resin will increase. Residual low molecular weight components can also lead to problems in the molding process.

The melt polymerization method is usually carried out in a multistage process of two or more stages. The polycondensation reaction may be carried out in two or more stages by using one polymerization reactor and sequentially changing the conditions, or by using two or more reactors and changing the respective conditions to perform two or more stages. 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 batch type, continuous type, or a combination of batch type and continuous type, but the continuous type is preferred 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 distill out of the reaction system. As a result, the molar ratio of the dihydroxy compound and the diester compound changes, and a polycarbonate resin with a desired molecular weight may not be obtained.
Moreover, the polymerization rate of the polycondensation reaction is controlled by the balance between the hydroxyl group terminal and the ester group terminal or carbonate group terminal. Therefore, especially in the case of continuous polymerization, if the balance of terminal groups fluctuates due to distillation of unreacted monomers, it becomes difficult to control the polymerization rate to be constant, and fluctuations in the molecular weight of the resulting polycarbonate resin increase. There is a risk. Since the molecular weight of the polycarbonate resin correlates with the melt viscosity, the melt viscosity may fluctuate during molding of the obtained polycarbonate resin, which may lead to problems such as the inability to obtain molded articles with uniform dimensions.

Furthermore, if unreacted monomers are distilled, not only the terminal group balance but also the copolymerization composition of the polycarbonate resin deviates from the desired composition, which may affect the mechanical properties and optical properties. In the retardation film, the wavelength dispersion of the retardation is controlled by the ratio of the fluorene-based monomer and other copolymer components in the polycarbonate resin. There is a risk that it will not be possible.

The process of the melt polycondensation reaction will be described below by dividing it into a step of consuming monomers to produce oligomers and a step of allowing polymerization to proceed to a desired molecular weight to produce polymers.
Specifically, the following conditions can be employed as reaction conditions in the first stage reaction. That is, the internal temperature of the polymerization reactor is usually 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. In addition, the pressure in the polymerization reactor is usually 70 kPa or less (hereinafter, pressure represents absolute pressure), 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. Also, the reaction time is set in the range of usually 0.1 hour or longer, preferably 0.5 hour or longer, and usually 10 hours or shorter, preferably 5 hours or shorter, more preferably 3 hours or shorter.

The first-stage reaction is carried out while distilling off 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 is, the more the polymerization reaction can be promoted, but on the other hand, the amount of unreacted monomer is increased. In order to simultaneously suppress the distillation of unreacted monomers and promote the reaction by reducing the pressure, it is effective to use a reactor equipped with a reflux condenser. In particular, it is preferable to use a reflux condenser at the initial stage of the reaction when there is a large amount of 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 subsequently generated monohydroxy compound is removed from the reaction system, while the pressure of the reaction system is finally reduced to 5 kPa or less. It is preferably 3 kPa or less, more preferably 1 kPa or less. The internal temperature is set in the range of usually 210° C. or higher, preferably 220° C. or higher, and usually 270° C. or lower, preferably 260° C. or lower. The reaction time is usually 0.1 hour or more, preferably 0.5 hour 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 coloration and heat deterioration and obtain a polycarbonate resin with good hue and heat stability, the maximum temperature of the internal temperature in all reaction stages is 270° C. or less, preferably 265° C. or less, more preferably 260° C. or less. do it.

The transesterification reaction catalyst (hereinafter sometimes simply referred to as catalyst or polymerization catalyst) that can be used during polymerization has a very large effect on the reaction rate and the color tone and thermal stability of the polycarbonate resin obtained by polycondensation. obtain. The catalyst to be used is not limited as long as it can satisfy the transparency, hue, heat resistance, thermal stability, and mechanical strength of the polycarbonate resin produced. group (hereinafter simply referred to as “group 1” and “group 2”) metal compounds, basic boron compounds, basic phosphorus compounds, basic ammonium compounds, basic compounds such as amine compounds. Preferably, at least one metal compound selected from the group consisting of metals of Group 2 of the long period periodic table and lithium is used.

As the above Group 1 metal compound, for example, the following compounds can be adopted, but it is also possible to adopt Group 1 metal compounds other than these. 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 borohydride, potassium borohydride, lithium borohydride, cesium borohydride, sodium tetraphenylborate, tetraphenyl potassium borate, lithium tetraphenylborate, cesium tetraphenylborate, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, Dicesium hydrogen phosphate, disodium phenyl phosphate, dipotassium phenyl phosphate, dilithium phenyl phosphate, diso cesium phenyl phosphate, alcoholates of sodium, potassium, lithium, cesium, phenolates, disodium salts of bisphenol A , 2 potassium salts, 2 lithium salts, 2 cesium salts. Among these, it is preferable to use a lithium compound from the viewpoint of the polymerization activity and the hue of the resulting polycarbonate resin.

As the Group 2 metal compound, for example, the following compounds can be adopted, but Group 2 metal compounds other than these can also be adopted. Calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium 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. Among these, it is preferable to use a magnesium compound, a calcium compound, and a barium compound. From the viewpoint of the polymerization activity and the hue of the resulting polycarbonate resin, it is more preferable to use a magnesium compound and/or a calcium compound, and a calcium compound is used. is most preferred.

In addition to the above Group 1 metal compound and/or Group 2 metal compound, it is also possible to use a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, an amine compound, etc. However, it is particularly preferable to use at least one metal compound selected from the group consisting of metals of Group 2 of the long period periodic table and lithium.
The amount of the polymerization catalyst used is generally 0.1 μmol to 300 μmol, preferably 0.5 μmol to 100 μmol, per 1 mol of all dihydroxy compounds used in the polymerization. When using at least one metal compound selected from the group consisting of metals of Group 2 of the long period periodic table and lithium as the polymerization catalyst, especially when using a magnesium compound and / or a calcium compound, the amount of metal is The above polymerization catalyst is usually used in an amount of 1.0 μmol or more, preferably 5.0 μmol or more, particularly preferably 10 μmol or more per 1 mol of the total dihydroxy compound. The amount of the polymerization catalyst used is generally 300 μmol or less, preferably 200 μmol or less, and particularly preferably 100 μmol or less.

Further, when a diester compound is used as a monomer to produce a polyester carbonate resin, a titanium compound, a tin compound, a germanium compound, an antimony compound, a zirconium compound, and lead are used in combination with or without the basic compound. Compounds, osmium compounds, zinc compounds, manganese compounds, and other transesterification catalysts can also be used. The amount of these transesterification catalysts to be used is usually in the range of 1 μmol to 1 mmol, preferably in the range of 5 μmol to 800 μmol, particularly preferably in the range of 5 μmol to 800 μmol, in terms of metal amount, per 1 mol of the total dihydroxy compounds used in the reaction. 10 μmol to 500 μmol.

If the amount of catalyst is too small, the polymerization rate will be slow, so the polymerization temperature will have to be raised accordingly in order to obtain a polycarbonate resin with a desired molecular weight. For this reason, the hue of the resulting polycarbonate resin is likely to deteriorate, and unreacted raw materials volatilize during polymerization, resulting in a loss of the molar ratio of the dihydroxy compound and the diester compound, which may prevent the desired molecular weight from being reached. have a nature. On the other hand, if the amount of the polymerization catalyst used is too large, undesirable side reactions may occur concurrently, resulting in deterioration of the hue of the resulting polycarbonate resin and coloration or decomposition of the polycarbonate resin during molding.

Among the Group 1 metals, sodium, potassium, and cesium may adversely affect the hue if contained in polycarbonate resin in large amounts. These metals may be mixed not only from the catalyst used, but also from raw materials and reactors. Regardless of the source, the total amount of these metal compounds in the polycarbonate resin is preferably 2 μmol or less, preferably 1 μmol or less, and more preferably 0.5 μmol or less per 1 mol of all the dihydroxy compounds.

After the polycarbonate resin is polymerized as described above, it can usually be solidified by cooling and pelletized with a rotary cutter or the like. The pelletization method is not limited, but may be a method of withdrawing in a molten state from the final-stage polymerization reactor, cooling and solidifying in the form of strands and pelletizing, a method of uniaxially or in a molten state from the final-stage polymerization reactor. A method in which polycarbonate resin is supplied to a twin-screw extruder, melt-extruded, and then solidified by cooling to form pellets. For example, the polycarbonate resin is supplied again to a single-screw or twin-screw extruder after being made into a single-screw or twin-screw extruder, melt-extruded, and then solidified by cooling to form pellets.

Since the polycarbonate resin is suitable for optical applications, it is preferable that the content of foreign matter in the polycarbonate resin is small. In order to remove foreign matters such as scorch and gel in the polycarbonate resin obtained by melt polycondensation, it is preferable to perform filtration using a filter. Above all, after the polycarbonate resin is melt-extruded with the above-mentioned vented twin-screw extruder in order to remove residual monomers, by-product phenol, etc. by devolatilizing under reduced pressure and to mix additives such as heat stabilizers and release agents. , preferably through a filter.

As for the shape of this filter, a known shape such as a candle type, pleated type, leaf disc type, etc. can be used. The mesh size of the filter is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 20 μm or less, as a filtration accuracy of 99%. When it is desired to particularly reduce foreign matter, the filter mesh size is preferably 10 μm or less. 99% filtration accuracy is preferably 1 μm or more. The opening of the filter mentioned here is determined in accordance with ISO16889.

The polycarbonate resin filtered by the above filter is extruded from the die head in the form of a strand, cooled and solidified, and pelletized with a rotary cutter or the like. is preferably performed in a clean room with a higher degree of cleanliness than Class 7, more preferably Class 6, defined in JISB 9920:2002, in order to prevent contamination from outside air.

When pelletizing, it is preferable to use a cooling method such as air cooling or water cooling. It is desirable to prevent redeposition of foreign matter. When water cooling is used, it is desirable to use water from which metals have been removed with an ion exchange resin or the like, and foreign matter has been removed from the water with a water filter. The mesh size of the water filter to be used is preferably 10 to 0.45 μm as filtration accuracy for 99% removal.

[Additive]
In polycarbonate resins, heat stabilizers, antioxidants, catalyst deactivators, ultraviolet absorbers, light stabilizers, mold release agents, dyes and pigments, impact modifiers, and electrifiers are added to the extent that the objects of the present invention are not impaired. Inhibitors, glidants, lubricants, plasticizers, compatibilizers, nucleating agents, flame retardants, inorganic fillers, blowing agents, and the like can also be included.

(Heat stabilizer)
If necessary, the polycarbonate resin may be blended with a heat stabilizer in order to prevent a decrease in molecular weight and a deterioration in hue during melt processing. Such heat stabilizers include commonly known hindered phenol heat stabilizers and/or phosphorus heat stabilizers.

As the hindered phenol compound, for example, the following compounds can be employed. 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- Preference is given to using butyl-4'-hydroxyphenyl)propionate, 1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene.

As the phosphorus compound, for example, the following phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid, esters thereof, and the like can be used, but phosphorus compounds other than these compounds can also be used. It is possible. triphenylphosphite, tris(nonylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tridecylphosphite, trioctylphosphite, trioctadecylphosphite, didecylmonophenylphosphite , dioctylmonophenylphosphite, diisopropylmonophenylphosphite, monobutyldiphenylphosphite, monodecyldiphenylphosphite, monooctyldiphenylphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol Diphosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite, bis(nonylphenyl)pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)penta Erythritol diphosphite, distearyl pentaerythritol diphosphite, tributyl phosphate, triethyl phosphate, trimethyl phosphate, triphenyl phosphate, diphenyl monoorthoxenyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, 4,4'-biphenylenediphosphinic acid Tetrakis(2,4-di-tert-butylphenyl), dimethyl benzenephosphonate, diethyl benzenephosphonate, dipropyl benzenephosphonate. These heat stabilizers may be used alone or in combination of two or more.

Such a heat stabilizer may be added to the reaction solution during melt polymerization, or may be added to the polycarbonate resin using an extruder and kneaded. When a film is formed by a 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 polycarbonate resin in advance using an extruder. Alternatively, it may be used in the form of pellets or the like.
The blending amount of these heat stabilizers is preferably 0.0001 parts by mass or more, more preferably 0.0005 parts by mass or more, further preferably 0.001 parts by mass or more, when the polycarbonate resin is 100 parts by mass. , is preferably 3.0 parts by mass or less, more preferably 2.5 parts by mass or less, and even more preferably 2.0 parts by mass or less.

(Catalyst deactivator)
Color tone and thermal stability can be improved by adding an acidic compound to the polycarbonate resin to neutralize and deactivate the catalyst used in the polymerization reaction. 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. It is preferable to use a phosphorus-based compound containing a partial structure represented by.

Phosphorus compounds represented by formula (16) or (17) above include phosphoric acid, phosphorous acid, phosphonic acid, hypophosphorous acid, polyphosphoric acid, phosphonic acid esters, acidic phosphate esters, and the like. Among the above, phosphorous acid, phosphonic acid, and phosphonic acid esters are more effective in deactivating the catalyst and suppressing coloration, and phosphorous acid is particularly preferred. Phosphonic acids include phosphonic acid (phosphorous acid), methylphosphonic acid, ethylphosphonic acid, vinylphosphonic acid, decylphosphonic acid, phenylphosphonic acid, benzylphosphonic acid, aminomethylphosphonic acid, methylenediphosphonic acid, 1-hydroxyethane- 1,1-diphosphonic acid, 4-methoxyphenylphosphonic acid, nitrilotris (methylenephosphonic acid), propylphosphonic anhydride and the like.

Phosphonates include dimethyl phosphonate, diethyl phosphonate, bis(2-ethylhexyl) phosphonate, dilauryl phosphonate, dioleyl phosphonate, diphenyl phosphonate, dibenzyl phosphonate, dimethyl methylphosphonate, diphenyl methylphosphonate, and 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, diethylphosphonoacetate, ethyl diethylphosphonoacetate, tert-butyl diethylphosphonoacetate, diethyl (4-chlorobenzyl)phosphonate, diethyl cyanophosphonate, diethyl cyanomethylphosphonate, 3,5 -di-tert-butyl-4-hydroxybenzylphosphonate diethyl, diethylphosphonoacetaldehyde diethylacetal, (methylthiomethyl)phosphonate diethyl and the like.

Acidic phosphates include dimethyl phosphate, diethyl phosphate, divinyl phosphate, dipropyl phosphate, dibutyl phosphate, bis(butoxyethyl) phosphate, bis(2-ethylhexyl) phosphate, diisotridecyl phosphate, phosphoric acid Phosphate diesters such as dioleyl, distearyl phosphate, diphenyl phosphate and dibenzyl phosphate, mixtures of diesters and monoesters, diethyl chlorophosphate, zinc stearyl phosphate and the like.

One of these may be used alone, or two or more of them may be mixed and used in any combination and ratio.
If the amount of the phosphorus-based compound added to the polycarbonate resin is too small, the effect of deactivating the catalyst and suppressing coloration is insufficient. In the durability test, the polycarbonate resin tends to be colored. The amount of the phosphorus-based compound to be added corresponds to the amount of the catalyst used in the polymerization reaction. The amount of phosphorus atoms in the phosphorus-based compound is preferably 0.5 to 5 times mol, more preferably 0.7 to 4 times mol, relative to 1 mol of the metal of the catalyst used in the polymerization reaction. It is preferably 0.8-fold mol or more and 3-fold mol or less is particularly preferable.

(polymer alloy)
Aromatic polycarbonates, aromatic polyesters, aliphatic polyesters, polyamides, polystyrenes, polyolefins, acrylics, amorphous polyolefins, ABS, AS, polylactic acid, and polybutylene succinate are used for the purpose of modifying properties such as mechanical properties and solvent resistance. A polymer alloy may be obtained by kneading one or more of synthetic resins such as phosphates, rubbers, elastomers, etc. with the polycarbonate resin.

The above-mentioned additives and modifiers are produced by mixing the above-mentioned components with the polycarbonate resin at the same time or in any order using a mixer such as a tumbler, a V-type blender, a Nauta mixer, a Banbury mixer, a kneading roll, and an extruder. However, kneading with an extruder, particularly a twin-screw extruder, is preferable from the viewpoint of improving dispersibility.

[Method for producing retardation film]
(Method for producing unstretched film)
As a method for forming an unstretched film using a polycarbonate resin, there is a casting method in which the polycarbonate resin is dissolved in a solvent and then cast, and then the solvent is removed. A melt film-forming method can be employed. Specific examples of the melt film-forming method include a melt extrusion method using a T-die, a calendar molding method, a hot press method, a co-extrusion method, a co-melting method, a multi-layer extrusion method, an inflation molding method, and the like. The method of forming the unstretched film is not particularly limited, but since the casting method may cause problems due to the residual solvent, the melt film forming method is preferable, and in particular, the T-die is used because of the ease of the subsequent stretching process. A hot melt extrusion method is preferred.

When an unstretched film is formed by a melt film-forming method, the forming 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, there is a possibility that defects due to the generation of foreign matter or air bubbles in the resulting film will increase, or that the film will be colored. However, if the molding temperature is too low, the melt viscosity of the polycarbonate resin will be too high, making it difficult to mold the original film and making it difficult to produce an unstretched film with a uniform thickness. is usually 200°C, preferably 210°C, more preferably 220°C. Here, the molding temperature of the unstretched film is the temperature at the time of molding in the melt film-forming method, and is usually the value obtained by measuring the temperature of the polycarbonate resin at the outlet of the die for extruding the molten polycarbonate resin.

Also, if foreign matter is present in the film, it will be recognized as a defect such as light leakage when used as a polarizing plate. In order to remove foreign substances in the polycarbonate resin, it is preferable to attach a polymer filter to the end of the extruder, filter the polycarbonate resin, and then extrude it through a die to form a film. At that time, it is necessary to connect the extruder, polymer filter, and die with pipes to transfer the molten polycarbonate resin. It is important to. In addition, the transporting and winding processes of the extruded film are performed in a clean room, and the utmost care is required to prevent foreign substances from adhering to the film.

The thickness of the unstretched film is determined according to the design of the thickness of the retardation film after stretching and the stretching conditions such as the stretching ratio. Therefore, it is usually 30 μm or more, preferably 40 μm or more, more preferably 50 μm or more, and is usually 200 μm or less, preferably 160 μm or less, more preferably 120 μm or less. In addition, if the unstretched film has thickness unevenness, the retardation unevenness of the retardation film is caused, so the thickness of the part used as the retardation film is preferably a set thickness ± 3 μm or less, and a set thickness ± 2 μm or less. It is more preferable that there is a thickness, and it is particularly preferable that the thickness is ±1 μm or less.

The length of the unstretched film in the longitudinal direction is preferably 500 m or longer, more preferably 1000 m or longer, and particularly preferably 1500 m or longer. From the viewpoint of productivity and quality, it is preferable to stretch continuously when manufacturing a retardation film. If the length is too short, the amount of product that can be obtained after conditioning will decrease. In this specification, the term "long" means that the dimension in the longitudinal direction is sufficiently larger than the width direction of the film, and the film can be substantially 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 at least ten times greater 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 greater than the above upper limit, light scattering may occur, which may cause depolarization, for example, when laminated with a polarizer. Although the lower limit of the internal haze is not specified, it is usually 0.1%. To measure the internal haze, a transparent film with adhesive, which had been measured in advance, was attached to both sides of the unstretched film, and the sample in which the influence of external haze was removed was used. The internal haze value is obtained by subtracting the haze value from the measured value of the above sample.

(Method for producing retardation film)
A retardation film can be obtained by stretching orienting the unstretched film. As a stretching method, known methods such as vertical uniaxial stretching, horizontal uniaxial stretching using a tenter or the like, simultaneous biaxial stretching combining them, and sequential biaxial stretching can be used. Stretching may be performed in batch mode, but continuous stretching is preferred in terms of productivity. Further, the continuous method can provide a retardation film with less variation in retardation in the film plane than the batch method.

The stretching temperature is 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 polycarbonate resin used as the raw material. More preferably, it is within the range of (Tg-5°C) to (Tg+15°C). The draw ratio is determined by the desired retardation value, and is 1.2 to 4 times, more preferably 1.5 to 3.5 times, and still more preferably 2 to 3 times in both the longitudinal and lateral directions. . 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 break or wrinkle during drawing.

The stretching rate is also appropriately selected depending on the purpose, but the strain rate represented by the following formula is usually 50 to 2000%/min, preferably 100 to 1500%/min, more preferably 200 to 1000%/min, especially Preferably, it can be selected to be 250-500%/min. An excessively high drawing speed may cause breakage during drawing, or increase the variation in optical properties due to long-term use under high-temperature conditions. On the other hand, if the drawing speed is too low, not only is the productivity lowered, but the draw ratio must be excessively increased to obtain the desired retardation.
Strain rate (%/min) = {stretching rate (mm/min)/raw film length (mm)} x 100

After stretching the film, if necessary, heat setting treatment may be performed in a heating furnace, or relaxation treatment may be performed by controlling the width of the tenter or adjusting the peripheral speed of the rolls. The temperature of the heat setting treatment is in the range of 60° C. to (Tg), preferably 70° C. to (Tg−5° C.) relative to the glass transition temperature (Tg) of the polycarbonate 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 and the desired retardation may be greatly reduced. Further, when a relaxation step is provided, the stress generated in the stretched film can be removed by shrinking it to 95% to 99% of the width of the film expanded by stretching. The treatment temperature applied to the film at this time is the same as the heat setting treatment temperature. By performing the heat setting treatment and the relaxation process as described above, it is possible to suppress fluctuations in optical properties due to long-term use under high-temperature conditions.

A retardation film can be produced by appropriately selecting and adjusting the processing conditions in such a stretching process. The retardation film preferably has an in-plane birefringence (Δn) at a wavelength of 550 nm of 0.001 or more, more preferably 0.0012 or more, and particularly preferably 0.0015 or more. Since the retardation is proportional to the thickness (d) and birefringence (Δn) of the film, by setting the birefringence in the above specific range, it is possible to express the desired retardation with a thin film, and the thin film A film compatible with the equipment can be easily produced. In order to develop high birefringence, the degree of orientation of the polymer molecules must be increased by lowering the stretching temperature, increasing the stretching ratio, etc. However, under such stretching conditions, the film tends to break. , the more excellent the toughness of the polycarbonate resin to be used, the more advantageous. Specifically, the higher the toughness of the film, for example, the more it is possible to suppress breakage at the clip portion during the film stretching process. Moreover, when the toughness is high, the film can be folded, bent back, and wound up, and can be applied to foldable applications, bendable applications, and winding applications. Specifically, the film is suitable as a member of a flexible display.

The retardation film preferably has a thickness of 110 μm or less, although it depends on the design value of the retardation. Further, the thickness of the retardation film is more preferably 105 μm or less, still more preferably 100 μm or less, and particularly preferably 95 μm or less. On the other hand, if the thickness is excessively thin, the film becomes difficult to handle, wrinkles occur during production, or breakage occurs. Therefore, the lower limit of the thickness of the retardation film is preferably 10 μm, more preferably 15 μm. is.

In the retardation film, the value of wavelength dispersion (R450/R550), which 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, is 0.60 or more and 1.00 or less. It is preferably 0.70 or more and 0.95 or less, and particularly preferably 0.80 or more and 0.90 or less. If the value of the wavelength dispersion is within this range, it is possible to obtain an ideal retardation characteristic over a wide wavelength range in the visible region. For example, by producing a retardation film having such wavelength dependence as a quarter-wave plate and bonding it to a polarizing plate, a circularly polarizing plate or the like can be produced, and a polarizing plate with less wavelength dependence of hue. and a display device. On the other hand, if the above ratio is out of this range, the wavelength dependence of the hue increases, optical compensation is not performed at all wavelengths in the visible region, and coloration and contrast are affected by light passing through the polarizing plate and the display device. Problems, such as a fall, arise.

The retardation film becomes a circularly polarizing plate by laminating it with a known polarizing film and cutting it into desired dimensions. Such a circularly polarizing plate is, for example, for viewing angle compensation of various displays (liquid crystal display device, organic EL display device, plasma display device, FED field emission display device, SED surface electric field display device), antireflection of external light, color It can be used for compensation, conversion of linearly polarized light into circularly polarized light, and the like.

Examples of polycarbonate copolymers are shown below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Various production conditions and values of evaluation results in the following examples have the meaning as preferable upper or lower limit values in the embodiments of the present invention, and the preferable range is the above upper or lower limit value and the following It may be a range defined by the value of the example or a combination of the values of the examples.
In addition, the measurement method and evaluation method of each physical property and characteristic are as follows.

(A) Glass transition temperature The glass transition temperature of the resin was measured 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 200° C. at a temperature elevation rate of 20° C./min under a nitrogen stream of 50 mL/min. After holding 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 again raised to 200° C. at a rate of 20° C./min. From the DSC data obtained in the second temperature increase, 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 becomes maximum. The extrapolated glass transition start temperature, which is the temperature at the intersection of , was determined and taken as the glass transition temperature.

(B) Measurement of water absorption Polycarbonate resin pellets were dried at a temperature of 100° C. for 12 hours or more under a reduced pressure of 200 Pa or less. Next, about 4 g of the dried pellets are placed on the top and bottom of the sample using a small heat press (AH-2003C AH-1TC, AS ONE Co., Ltd.), using spacers of 14 cm in length, 14 cm in width, and 0.1 mm in thickness. A film was laid, preheated at a temperature of 200 to 230° C. for 3 minutes, pressurized at a pressure of 7 MPa for 5 minutes, taken out together with the spacer, and cooled to prepare a film.

The obtained film was cut into a square of 100 mm long and 100 mm wide to prepare a sample. This sample was dried at a glass transition temperature of −10° C. for 24 hours or more under a reduced pressure of 200 Pa or less. The mass of the sample after drying was weighed to 0.1 mg, and this value was defined as the dry mass. Next, the dried sample was immersed in desalted water adjusted to 23° C. for 72 hours or more. After immersion, the sample was taken out of the water, and the water on the surface was wiped off with a clean and dry cloth or filter paper. The water absorption mass was measured within 1 minute after being removed from the water. Water absorption was determined using Equation 1.
(Water absorption mass - dry mass)/dry mass x 100 = water absorption rate (%) Equation 1

(C) Reduced Viscosity of Resin The above resin was dissolved in methylene chloride to prepare a resin solution having a concentration of 0.6 g/dL. Measurement was performed at a temperature of 20.0° C.±0.1° C. using an Ubbelohde viscosity tube manufactured by Moritomo Rika Kogyo Co., Ltd., and the passage time _t0 of the solvent and the passage time t of the solution were measured. Using the obtained values of _t0 and t, the relative viscosity η _rel was determined by the following equation (I), and the relative viscosity η _rel thus obtained was used to determine the specific viscosity η _sp by the following equation (ii). .
η _rel =t/t ₀ (I)
η _sp =(η−η ₀ )/η ₀ =η _rel −1 (ii)
Thereafter, the obtained specific viscosity η _sp was divided by the concentration c (g/dL) to obtain the reduced viscosity η _sp /c. The higher this value, the larger the molecular weight.

<Evaluation of unstretched film>
(D) Molding of Unstretched Film Polycarbonate resin pellets were dried at a temperature of 100° C. for 12 hours or more under a reduced pressure of 200 Pa or less. Next, about 4 g of the dried pellets are placed on the top and bottom of the sample using a small heat press (AH-2003C AH-1TC, AS ONE Co., Ltd.), using spacers of 14 cm in length, 14 cm in width, and 0.1 mm in thickness. A film was laid, preheated at a temperature of 200 to 230° C. for 3 minutes, pressurized at a pressure of 7 MPa for 5 minutes, taken out together with the spacer, and cooled to prepare an unstretched film.

(E) Measurement of photoelastic coefficient A device combining a birefringence measuring device consisting of a He—Ne laser, a polarizer, a compensator, an analyzer, and a photodetector and a vibration type viscoelasticity measuring device (DVE-3 manufactured by Rheology). was measured using (For details, see Journal of the Japanese Society of Rheology, Vol. 19, p93-97 (1991).)
A test piece having a length of 20 mm and a width of 5 mm was cut out from the above unstretched film, fixed to a viscoelasticity measuring device, and the storage elastic modulus E′ was measured at a room temperature of 25° C. and 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 (photodiode), and passed through a lock-in amplifier to obtain a waveform with an angular frequency of ω or 2ω. A phase difference was determined, and a distortion optical coefficient O' was determined. At this time, the directions of the polarizer and the analyzer were orthogonal to each other, and adjusted to form an angle of π/4 with respect to the stretching 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'
In the following examples and comparative examples, those with a photoelastic coefficient of 19 × 10 ^-12 Pa ^-1 or less were evaluated as having small changes in optical properties due to expansion and contraction of the film due to changes in the usage environment. bottom.

(F) Film toughness (bending test)
An unstretched film having a thickness of 100 to 200 μm was produced by the method described above, and a rectangular test piece having a length of 40 mm and a width of 10 mm was produced from this film. The distance between the joint surfaces on the left and right sides of the vise was set to 40 mm, and both ends of the test piece were fixed within the joint surfaces. Next, the gap between the left and right joint surfaces is narrowed at a speed of 2 mm/second or less, and the entire film bent in a substantially U-shape is moved to the joint surface while preventing the film from protruding outside the joint surface of the vise. It was compressed inside. If the test piece breaks into 2 pieces (or 3 pieces or more) at the bent portion until the joint surfaces are in complete contact, "cracked" is indicated, and the test piece is still in contact with the joint surfaces. When it was bent without cracking, it was evaluated as "no cracking". The test was repeated 5 times for the same type of film, and if it was "cracked" three or more times, it was "x: brittle fracture", and if it was "cracked" twice or less, it was "○. : no brittle fracture", and those that did not brittle fracture were evaluated as having excellent toughness.

(G) moist heat resistance test (pressure cooker (PCT) test)
The above-mentioned unstretched film is steamed under the conditions of 110 ° C., 0.15 Mpa, 100% RH, 24 hours using a laboratory autoclave (LSX-300) manufactured by Tomy Seiko Co., Ltd. Before and after the test. The change in the shape of the film and the presence or absence of whitening were confirmed.
<Evaluation>
〇: No opaque part at all, or only partly opaque ×: Entirely opaque

<Evaluation of Retardation Film>
(H) Stretching of film A film piece having a width of 50 mm and a length of 125 mm is cut out from the unstretched film, and a batch type biaxial stretching device (Biaxial stretching device BIX-277-AL manufactured by Island Industry Co., Ltd.) is used to stretch the resin glass. The above film piece was uniaxially stretched at the free end at a stretching temperature of transition temperature +15°C, a stretching speed of 300%/min and a stretching ratio of 1.5 times to obtain a stretched film.

(I) Retardation, wavelength dispersion, and birefringence of the stretched film Cut out the central portion of the stretched film obtained by the above method to have a width of 4 cm and a length of 4 cm, and use a retardation measuring device KOBRA-WPR manufactured by Oji Scientific Instruments Co., Ltd. was used to measure the retardation at measurement wavelengths of 450, 500, 550, 590 and 630 nm, and the wavelength dispersion was measured. The wavelength dispersion was indicated by the ratio (R450/R550) of the phase differences R450 and R550 measured at 450 nm and 550 nm. When R450/R550 is greater than 1, the chromatic dispersion is positive, and when it is less than 1, the chromatic dispersion is reversed. When used as a quarter-wave plate, the ideal value of R450/R550 is 0.818 (450/550=0.818).

Also, using the retardation R550 of 550 nm and the thickness of the stretched film, the birefringence Δn can be obtained from the following equation. Birefringence=R550 [nm]/(film thickness [mm]×10 ⁶ ) A larger value of birefringence indicates a higher degree of orientation of the polymer. Also, the larger the birefringence value, the thinner the film thickness for obtaining the desired retardation value.

[raw materials used]
The abbreviations of the compounds used in the following Examples and Production Examples and the manufacturers are as follows.

[monomer]
・SPG: Spiroglycol (manufactured by Mitsubishi Gas Chemical Company, Inc.)
・ISB: Isosorbide (manufactured by Rocket Fleuret)
・ PEG-1000: polyethylene glycol (manufactured by Sanyo Kasei Co., Ltd.)
・ BP-TMC: 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (manufactured by Honshu Chemical Co., Ltd.)
・BisP-CDE: 4,4′-(cyclododecane-1,1-diyl)diphenol (manufactured by Honshu Chemical Co., Ltd.)
・ BCF: 9,9-bis (4-hydroxy-2-methylphenyl) fluorene (manufactured by Honshu Chemical Co., Ltd.)
・ BisP-AP: 4,4'-(α-methylbenzylidene) bisphenol (manufactured by Honshu Chemical Co., Ltd.)
・ BHEPF: 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (manufactured by Honshu Chemical Co., Ltd.)

· SBI: 6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane Synthesized according to the method described in paragraph number [0264] of JP-A-2014-114281.

BPFM: Bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane Synthesized by the method described in paragraph number [0596] of JP-A-2015-25111.

・DPC: diphenyl carbonate (manufactured by Mitsubishi Chemical Corporation)

[Example 1]
Each raw material was prepared so that the content of each structural unit was the value shown in Table 1. Specifically, first, BP-TMC 30.20 parts by mass (0.097 mol), SPG 37.77 parts by mass (0.124 mol), BPFM 39.47 parts by mass (0.062 mol), DPC 35.41 parts by mass (0.165 mol), and 1.17×10 ⁻² parts by mass (6.64×10 ⁻⁵ mol) of calcium acetate monohydrate as a catalyst were put into a reaction vessel, and the inside of the reactor was replaced with nitrogen under reduced pressure. . The raw materials were dissolved under a nitrogen atmosphere with stirring at 150° C. for about 10 minutes. 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 and maintained at 13.3 kPa for 30 minutes, and the generated phenol was discharged out of the reaction system. Next, as the second step of the reaction, the temperature of the heating medium was raised to 260° C. over 15 minutes while the pressure was reduced to 0.10 kPa or less over 15 minutes, and the generated phenol was discharged out of the reaction system. After reaching a predetermined stirring torque, the pressure was restored to normal pressure with nitrogen to stop the reaction, the polyester carbonate produced was extruded into water, and the strand was cut to obtain pellets. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3. Table 1 shows the charge of raw materials in units of mol %, and Table 2 shows the charge of raw materials in mass %.

[Example 2]
BP-TMC 30.20 parts by mass (0.097 mol), SPG 39.50 parts by mass (0.130 mol), BPFM 36.65 parts by mass (0.057 mol), DPC 37.60 parts by mass (0.176 mol), Polyester carbonate pellets were obtained in the same manner as in Example 1, except that 1.20×10 ⁻² parts by mass (6.81×10 ⁻⁵ mol) of calcium acetate monohydrate was used as a catalyst. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 3]
BP-TMC 30.20 parts by mass (0.097 mol), SPG 41.23 parts by mass (0.135 mol), BPFM 33.83 parts by mass (0.053 mol), DPC 39.79 parts by mass (0.186 mol), Polyester carbonate pellets were obtained in the same manner as in Example 1, except that 1.23×10 ⁻² parts by mass (6.98×10 ⁻⁵ mol) of calcium acetate monohydrate was used as a catalyst. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. Evaluation results are shown in Tables 1 to 3.

[Example 4]
BP-TMC 30.20 parts by mass (0.097 mol), SPG 42.96 parts by mass (0.141 mol), BPFM 31.01 parts by mass (0.048 mol), DPC 41.98 parts by mass (0.196 mol), Polyester carbonate pellets were obtained in the same manner as in Example 1, except that 1.26×10 ⁻² parts by mass (7.15×10 ⁻⁵ mol) of calcium acetate monohydrate was used as a catalyst. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 5]
BP-TMC 30.20 parts by mass (0.097 mol), SPG 44.69 parts by mass (0.147 mol), BPFM 28.19 parts by mass (0.044 mol), DPC 44.17 parts by mass (0.206 mol), Polyester carbonate pellets were obtained in the same manner as in Example 1, except that 1.29×10 ⁻² parts by mass (7.32×10 ⁻⁵ mol) of calcium acetate monohydrate was used as a catalyst. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 6]
BisP-AP 30.21 parts by mass (0.104 mol), SPG 40.19 parts by mass (0.132 mol), BPFM 35.24 parts by mass (0.055 mol), DPC 40.06 parts by mass (0.187 mol), Polyester carbonate pellets were obtained in the same manner as in Example 1, except that 1.25×10 ⁻² parts by mass (7.08×10 ⁻⁵ mol) of calcium acetate monohydrate was used as a catalyst. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 7]
BisP-CDE 30.17 parts by mass (0.086 mol), SPG 43.26 parts by mass (0.142 mol), BPFM 31.01 parts by mass (0.048 mol), DPC 39.64 parts by mass (0.185 mol), Polyester carbonate pellets were obtained in the same manner as in Example 1, except that 1.20×10 ⁻² parts by mass (6.83×10 ⁻⁵ mol) of calcium acetate monohydrate was used as a catalyst. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 8]
BisP-CDE 30.17 parts by mass (0.086 mol), SPG 40.67 parts by mass (0.134 mol), BPFM 35.24 parts by mass (0.055 mol), DPC 36.35 parts by mass (0.170 mol), Polyester carbonate pellets were obtained in the same manner as in Example 1, except that 1.16×10 ⁻² parts by mass (6.58×10 ⁻⁵ mol) of calcium acetate monohydrate was used as a catalyst. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 9]
BP-TMC 20.13 parts by mass (0.065 mol), SPG 52.15 parts by mass (0.171 mol), BPFM 20.13 parts by mass (0.051 mol), DPC 41.02 parts by mass (0.191 mol), Polyester carbonate pellets were obtained in the same manner as in Example 1, except that 1.25×10 ⁻² parts by mass (7.09×10 ⁻⁵ mol) of calcium acetate monohydrate was used as a catalyst. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 10]
BP-TMC 20.13 parts by mass (0.065 mol), SPG 41.14 parts by mass (0.135 mol), ISB 10.14 parts by mass (0.069 mol), BPFM 32.42 parts by mass (0.051 mol), Using 48.31 parts by mass (0.226 mol) of DPC and 1.42×10 ⁻² parts by mass (8.08×10 ⁻⁵ mol) of calcium acetate monohydrate as a catalyst, heat was used as the second step of the reaction. Polyester carbonate pellets were obtained in the same manner as in Example 1, except that the medium temperature was raised to 245° C. over 15 minutes. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 11]
BP-TMC 10.06 parts by mass (0.032 mol), SPG 35.12 parts by mass (0.115 mol), ISB 25.35 parts by mass (0.173 mol), BPFM 31.72 parts by mass (0.049 mol), Using 58.91 parts by mass (0.275 mol) of DPC and 1.70×10 ⁻² parts by mass (9.64×10 −5 mol) of calcium acetate monohydrate as a catalyst, a heating medium was used in the second step of the reaction. Polyester carbonate pellets were obtained in the same manner as in Example 1, except that the temperature was raised to 250° C. over 15 minutes. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 12]
BP-TMC 15.10 parts by mass (0.049 mol), SPG 52.97 parts by mass (0.174 mol), ISB 5.07 parts by mass (0.035 mol), BPFM 30.31 parts by mass (0.047 mol), Using 46.37 parts by mass (0.216 mol) of DPC and 1.36×10 ⁻² parts by mass (7.72×10 −5 mol) of calcium acetate monohydrate as a catalyst, a heat medium was used in the second step of the reaction. Polyester carbonate pellets were obtained in the same manner as in Example 1, except that the temperature was raised to 250° C. over 15 minutes. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 13]
BisP-CDE 20.11 parts by mass (0.057 mol), SPG 41.35 parts by mass (0.136 mol), ISB 10.14 parts by mass (0.069 mol), BPFM 32.42 parts by mass (0.051 mol), Using 46.75 parts by mass (0.218 mol) of DPC and 1.39×10 ⁻² parts by mass (7.87×10 −5 mol) of calcium acetate monohydrate as a catalyst, a heating medium was used in the second step of the reaction. Polyester carbonate pellets were obtained in the same manner as in Example 1, except that the temperature was raised to 250° C. over 15 minutes. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Example 14]
BisP-CDE 10.06 parts by mass (0.029 mol), SPG 36.52 parts by mass (0.120 mol), ISB 25.35 parts by mass (0.173 mol), BPFM 29.60 parts by mass (0.046 mol), Using 59.76 parts by mass (0.279 mol) of DPC and 1.70×10 ⁻² parts by mass (9.66×10 −5 mol) of calcium acetate monohydrate as a catalyst, a heating medium was used in the second step of the reaction. Polyester carbonate pellets were obtained in the same manner as in Example 1, except that the temperature was raised to 250° C. over 15 minutes. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. The results are shown in Tables 1-3.

[Comparative Example 1]
SBI 25.16 parts by mass (0.082 mol), SPG 56.62 parts by mass (0.186 mol), BPFM 16.92 parts by mass (0.026 mol), DPC 52.82 parts by mass (0.247 mol), and a catalyst Pellets of polyester carbonate were obtained in the same manner as in Example 1, except that 1.41×10 ⁻² parts by mass (8.03×10 ⁻⁵ mol) of calcium acetate monohydrate was used as. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. Tables 1 to 2 and 4 show the results.

[Comparative Example 2]
SBI 20.13 parts by mass (0.065 mol), SPG 48.91 parts by mass (0.161 mol), ISB 10.14 parts by mass (0.069 mol), BPFM 19.74 parts by mass (0.031 mol), DPC 58 .25 parts by mass (0.272 mol) and 1.56×10 ⁻² parts by mass (8.86×10 ⁻⁵ mol) of calcium acetate monohydrate as a catalyst, and a heat medium Polycarbonate pellets were obtained in the same manner as in Example 1, except that the temperature was raised to 250° C. over 15 minutes. Using the obtained polycarbonate pellets, the various evaluations described above were carried out. Tables 1 to 2 and 4 show the results.

[Comparative Example 3]
SPG 30.20 parts by mass (0.099 mol), ISB 39.94 parts by mass (0.273 mol), BPFM 30.31 parts by mass (0.047 mol), DPC 69.67 parts by mass (0.325 mol), and a catalyst Pellets of polyester carbonate were obtained in the same manner as in Example 10, except that 9.84×10 ⁻⁴ parts by mass (5.59×10 ⁻⁶ mol) of calcium acetate monohydrate was used. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. Tables 1 to 2 and 4 show the results.

[Comparative Example 4]
ISB 26.72 parts by mass (0.183 mol), PEG1000 # 0.99 parts by mass (0.001 mol), BHEPF 63.74 parts by mass (0.145 mol), DPC 70.24 parts by mass (0.328 mol), and Polycarbonate pellets were obtained in the same manner as in Comparative Example 3, except that 8.69×10 ⁻⁴ parts by mass (4.93×10 ⁻⁶ mol) of calcium acetate monohydrate was used as a catalyst. Using the obtained polycarbonate pellets, the various evaluations described above were carried out. Tables 1 to 2 and 4 show the results.

[Comparative Example 5]
BP-TMC 10.07 parts by mass (0.032 mol), ISB 54.13 parts by mass (0.370 mol), BPFM 38.06 parts by mass (0.059 mol), DPC 74.43 parts by mass (0.347 mol), And 1.06×10 −3 parts by mass (6.04×10 ⁻⁶ mol) of calcium acetate monohydrate as a catalyst, and the temperature of the heating medium was raised to 250° C. over 15 minutes in the second step of the reaction. Polycarbonate pellets were obtained in the same manner as in Example 1 except that the mixture was heated. Using the obtained polycarbonate pellets, the various evaluations described above were carried out. Tables 1 to 2 and 4 show the results.

[Comparative Example 6]
BP-TMC 24.16 parts by mass (0.078 mol), ISB 28.45 parts by mass (0.195 mol), BPFM 30.45 parts by mass (0.048 mol), DPC 49.70 parts by mass (0.232 mol), And 1.44×10 −3 parts by mass (8.18×10 ⁻⁶ mol) of calcium acetate monohydrate as a catalyst, and the temperature of the heating medium was raised to 250° C. over 15 minutes in the second step of the reaction. Polycarbonate pellets were obtained in the same manner as in Example 1 except that the mixture was heated. The polycarbonate obtained in this comparative example was brittle, and it was not possible to produce a film molded article, so evaluation using a film molded article could not be performed.

[Comparative Example 7]
BCF 38.18 parts by mass (0.101 mol), SPG 54.56 parts by mass (0.179 mol), DPC 62.40 parts by mass (0.291 mol), and calcium acetate monohydrate 2.47 × 10 as a catalyst Pellets of polyester carbonate were obtained in the same manner as in Example 1 except that -2 parts by mass (1.40×10 ⁻⁴ mol) were used. Using the obtained polyester carbonate pellets, the various evaluations described above were carried out. Tables 1 to 2 and 4 show the results.

As is clear from Tables 1 to 3, the polycarbonate resins of Examples 1 to 14 containing structural units (A), structural units (B), and structural units (C) are excellent in heat and humidity resistance and optical properties. On the other hand, as is clear from Tables 1, 2 and 4, the polycarbonate resins of Comparative Examples 1 to 3, which do not contain the structural unit (B), have low wet heat resistance or toughness. Also, the polycarbonate resin of Comparative Example 4 containing no structural unit (A), structural unit (B), or structural unit (C) is inferior in optical properties. Comparative Example 5, which does not contain the structural unit (C), is not suitable for use as a retardation film under high humidity and heat because of its high water absorption rate and large dimensional change rate. Poor melt processability due to high viscosity. Moreover, Comparative Example 6, which does not contain the structural unit (C), cannot be formed into a film, and has poor formability. Moreover, Comparative Example 7, which does not contain the structural unit (A), has low toughness.

Claims

a structural unit (A) represented by the following formula (1) and/or the following formula (2);
A structural unit (B) represented by the following formula (3);
and a structural unit (C) derived from a dihydroxy compound having an acetal ring structure.

(In formula (1) above, R 1 to R 3 each independently represent a direct bond or a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, and R 4 to R 9 each independently, a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a substituted or unsubstituted acyl group having 2 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms, substituted or unsubstituted amino group, substituted or unsubstituted vinyl group having 2 to 10 carbon atoms, substitution or an unsubstituted ethynyl group having 2 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 ; may be present or different, and at least two adjacent groups among R 4 to R 9 may be bonded to each other to form a ring.)

(In formula (2) above, R 1 to R 3 each independently represent a direct bond or a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, and R 4 to R 9 each independently, a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a substituted or unsubstituted acyl group having 2 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms, substituted or unsubstituted amino group, substituted or unsubstituted vinyl group having 2 to 10 carbon atoms, substitution or an unsubstituted ethynyl group having 2 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 ; may be present or different, and at least two adjacent groups among R 4 to R 9 may be bonded to each other to form a ring.)

(where, in the above formula (3), R 10 to R 17 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted represents an aryl group, and X 1 represents a direct bond or a divalent hydrocarbon group having 1 to 20 carbon atoms.)
R 10 to R 17 in the above formula (3) are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms is a group, and X 1 is a substituted or unsubstituted 1 to 20 chain alkylene group, a substituted or unsubstituted cyclic alkylene group having 6 to 20 carbon atoms, an arylene group having 6 to 20 carbon atoms, or The polycarbonate resin according to claim 1, which is a fluorenylene group having 13 to 20 carbon atoms.
The content of the structural unit (A) is 1% by mass or more and 45% by mass or less with respect to the total 100% by mass of the content of all structural units and linking groups constituting the polycarbonate resin, or 2. The polycarbonate resin according to 2 above.
Claims 1 to 5, wherein the content of the structural unit (B) is 5% by mass or more and 50% by mass or less with respect to the total 100% by mass of the content of all structural units and linking groups constituting the polycarbonate resin. 4. The polycarbonate resin according to any one of 3.
The content of the structural unit (C) is 15% by mass or more and 75% by mass or less with respect to the total 100% by mass of the content of all structural units and linking groups constituting the polycarbonate resin, claims 1 to 5. The polycarbonate resin according to any one of 4.
Furthermore, claims 1 to 5, comprising a structural unit (D) derived from at least one compound selected from the group consisting of aliphatic dihydroxy compounds, alicyclic dihydroxy compounds, oxyalkylene glycols and dihydroxy compounds having a heterocyclic structure. Polycarbonate resin according to any one of.
The total content of the structural unit (C) and the structural unit (D) is 20% by mass or more and 80% by mass with respect to the total 100% by mass of the content of all structural units and linking groups constituting the polycarbonate resin. % or less, the polycarbonate resin according to claim 6.
8. The structural unit according to claim 6 or 7, wherein the structural unit (C) is a structural unit represented by the following formula (4), and the structural unit (D) is a structural unit represented by the following formula (5). Polycarbonate resin.
The polycarbonate resin according to any one of claims 1 to 8, wherein the polycarbonate resin has a glass transition temperature of 120°C or higher and 160°C or lower.
The polycarbonate resin according to any one of claims 1 to 9, wherein the polycarbonate resin has a water absorption rate of 1.4% or less.
A polycarbonate resin molded article composed of the polycarbonate resin according to any one of claims 1 to 10.
A film composed of the polycarbonate resin according to any one of claims 1 to 10.
A retardation film made of the film according to claim 12.
14. The retardation film according to claim 13, wherein the film has a wavelength dispersion value, which is a ratio of a retardation R450 at a wavelength of 450 nm to a retardation R550 at a wavelength of 550 nm, of 0.60 or more and 1.00 or less.
A circularly polarizing plate, comprising the retardation film according to claim 13 or 14.
An image display device comprising the circularly polarizing plate according to claim 15.
A method for producing a transparent film by molding the polycarbonate resin according to any one of claims 1 to 10 by a melt film forming method,
A method for producing a transparent film, wherein the polycarbonate resin is molded at a molding temperature of 280° C. or less.
a structural unit (A) represented by the following formula (1) and/or the following formula (2);
and a structural unit (B) represented by the following formula (3),
a glass transition temperature of 120° C. or higher and 160° C. or lower;
A polycarbonate resin having a water absorption of 1.4% or less.

(In formula (1) above, R 1 to R 3 each independently represent a direct bond or a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, and R 4 to R 9 each independently, a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a substituted or unsubstituted acyl group having 2 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms, substituted or unsubstituted amino group, substituted or unsubstituted vinyl group having 2 to 10 carbon atoms, substitution or an unsubstituted ethynyl group having 2 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 ; may be present or different, and at least two adjacent groups among R 4 to R 9 may be bonded to each other to form a ring.)

(In formula (2) above, R 1 to R 3 each independently represent a direct bond or a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, and R 4 to R 9 each independently, a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a substituted or unsubstituted acyl group having 2 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms, substituted or unsubstituted amino group, substituted or unsubstituted vinyl group having 2 to 10 carbon atoms, substitution or an unsubstituted ethynyl group having 2 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 ; may be present or different, and at least two adjacent groups among R 4 to R 9 may be bonded to each other to form a ring.)

(where, in the above formula (3), R 10 to R 17 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted represents an aryl group, and X 1 represents a direct bond or a divalent hydrocarbon group having 1 to 20 carbon atoms.)