JP2015199950A - Polyester resin for retardation film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin for a retardation film, which has excellent heat resistance and exhibits an excellent balance in birefringence and reverse wavelength dispersion when formed into a sheet or a film, that is, a resin for a retardation film, which has excellent heat resistance, high in-plane retardation, and low wavelength dispersion of in-plane retardation.SOLUTION: A polyester resin for a retardation film is provided, including a diol component (A) and a dicarboxylic acid component (B) as a polymerization component, in which the diol component comprises a 9,9-bis(hydroxy(poly)alkoxyaryl)fluorene component (A1); and the dicarboxylic acid component comprises a dicarboxylic acid component (B1) having a fluorene skeleton.

Description

  The present invention relates to a polyester resin for retardation film and a retardation film using the same.

  The retardation film is used in an STN (super twisted nematic) system of a liquid crystal display device, and is used to solve problems such as color compensation and viewing angle expansion. In particular, a retardation film having reverse wavelength dispersion has functions such as color compensation, widening of a viewing angle, and antireflection of external light, and is used in an image display device and the like.

  As this retardation film, a retardation film made of a polycarbonate resin having a specific fluorene skeleton is known (for example, Patent Document 1). However, the polycarbonate resin has a high glass transition temperature, and it is difficult to form a film by the melt film forming method. Therefore, from the viewpoint of film thickness unevenness, appearance, etc., the retardation film made of the polycarbonate resin is usually formed by the solution casting method. Has been.

  However, since the solution casting method often uses a solvent such as methylene chloride or dichloromethane as a solvent, it has a large environmental load and may cause corrosion of manufacturing equipment. For this reason, it is preferable that a retardation film can be manufactured without using the solution casting method.

  In order to solve such problems, it is known that an aliphatic diol is copolymerized when a polycarbonate resin is synthesized (for example, Patent Documents 2 and 3). However, since the thermal stability is poor, as a result, the molecular weight tends to decrease during melt film formation, and there are also problems such as brittleness and coloring.

  On the other hand, as described above, not only a polycarbonate resin having poor processability, but also a polyester resin, in either a diol component or a dicarboxylic acid component, there is an investigation of a retardation film using a polyester resin using a compound having a fluorene skeleton. (For example, patent document 4 etc.). However, sufficient results have not yet been obtained for the optical properties of the retardation film.

Japanese Patent No. 3325560 International Publication No. 2006/041190 International Publication No. 2010/064721 Japanese Patent No. 4797997

  The resin used for the retardation film exhibits optical properties as a retardation film, and therefore has heat resistance, excellent birefringence when formed into a sheet or film, and increases reverse wavelength dispersion. Is required. In particular, since all common organic materials have positive wavelength dispersion, in order to use it as a retardation film, it was necessary to superimpose two films at an appropriate angle. If a resin with improved dispersibility is used, it is possible to form a retardation film with only one sheet. However, birefringence and inverse wavelength dispersion are in a so-called trade-off relationship in which either of them improves, and it is very difficult to improve both. In general, the in-plane retardation (R550 nm) at a measurement wavelength of 550 nm, which is an index of birefringence, is preferably large, and the in-plane retardation at the measurement wavelength of 450 nm, which is an index of reverse wavelength dispersion, and the in-plane position at a measurement wavelength of 550 nm. The ratio to the phase difference (R450nm / R550nm) is preferably 0.82. However, because of the above trade-off relationship, R550nm is brought close to 140nm and R450nm / R550nm is set to 0.82 for balance. It is considered ideal to be close.

  Therefore, the present invention is a resin for a retardation film that is excellent in heat resistance and has a good balance between birefringence and reverse wavelength dispersion when formed into a sheet or film, that is, excellent in heat resistance and has a high in-plane retardation. An object of the present invention is to provide a resin for retardation film having low in-plane retardation wavelength dispersion.

As a result of intensive research, the inventors of the present invention have solved the above-described problems with a polyester resin having a fluorene skeleton in either the diol component or the dicarboxylic acid component (having a specific fluorene skeleton in the diol component). It has been found that a resin for a retardation film having excellent heat resistance and excellent balance between birefringence and reverse wavelength dispersion when formed into a sheet or film can be obtained. When this polyester resin is used, a retardation film can be obtained by a melt film forming method. The present invention has been completed by further research based on such knowledge. That is, the present invention includes the following configurations.
Item 1. A polyester resin for a retardation film having a diol component (A) and a dicarboxylic acid component (B) as polymerization components,
The diol component includes a 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1), and
The said dicarboxylic acid component is a polyester resin for retardation films containing the dicarboxylic acid component (B1) which has a fluorene skeleton.
Item 2. Item 2. The polyester resin for retardation film according to Item 1, wherein the diol component (A) further includes an aliphatic diol component (A2).
Item 3. Item 3. The polyester resin for retardation film according to Item 1 or 2, wherein the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) content in the diol component (A) is 40 mol% or more. .
Item 4. The total amount of the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) and the aliphatic diol component (A2) in the diol component (A) is 50 mol% based on the entire diol component (A). Item 4. The polyester resin for retardation film according to item 2 or 3, which is as described above.
Item 5. Item 5. The polyester resin for retardation film according to any one of Items 1 to 4, wherein the dicarboxylic acid component (B1) having a fluorene skeleton is a dicarboxylic acid ester-forming derivative component having a fluorene skeleton.
Item 6. Item 6. The polyester resin for retardation film according to any one of Items 1 to 5, wherein the dicarboxylic acid component (B) further includes a non-fluorene aromatic dicarboxylic acid component (B2).
Item 7. Item 7. The polyester resin for retardation film according to Item 6, wherein the non-fluorene aromatic dicarboxylic acid component (B2) is a monocyclic aromatic dicarboxylic acid component.
Item 8. Item 8. The polyester resin for retardation film according to any one of Items 1 to 7, wherein the content of the dicarboxylic acid component (B1) having a fluorene skeleton in the dicarboxylic acid component (B) is 5 mol% or more.
Item 9. Item 9. The polyester resin for retardation film according to any one of Items 1 to 8, wherein the glass transition temperature is 120 to 200 ° C.
Item 10. The retardation film using the polyester resin for retardation films in any one of claim | item 1 -9.
Item 11. Item 11. The method for producing a retardation film according to Item 10, wherein a sheet or film-like material is formed from the polyester resin for retardation film or the resin composition containing the polyester resin for retardation film.
Item 12. Item 12. The method for producing a retardation film according to Item 11, wherein a melt film-forming method is employed when the sheet or film-like material is formed.
Item 13. Item 13. The method for producing a retardation film according to Item 11 or 12, wherein the sheet or film is stretched in at least one direction.
Item 14. Item 11. A circularly polarizing plate or an elliptically polarizing plate comprising the retardation film according to Item 10 or the retardation film obtained by the production method according to any one of Items 11 to 13, and a polarizing plate and / or a reflective polarizing plate.
Item 15. Item 14. An image display device comprising the retardation film according to Item 10 or the retardation film obtained by the production method according to any one of Items 11 to 13.

  According to the present invention, a polyester resin having excellent heat resistance can be provided, and when the polyester resin is formed into a sheet or film, the balance between birefringence and reverse wavelength dispersion is excellent. That is, when the polyester resin of the present invention is formed on a sheet or film, a retardation film having a high in-plane retardation and low in-plane retardation wavelength dispersibility can be obtained. For this reason, the polyester resin of the present invention is particularly useful for a retardation film. If the polyester resin of the present invention is used, a retardation film can be obtained by a melt film-forming method, so that the problem of environmental load and corrosion of manufacturing equipment can also be solved.

  In the present specification, the “dicarboxylic acid component” includes not only dicarboxylic acids but also dicarboxylic acid derivatives such as dicarboxylic acid ester-forming derivatives, unless otherwise specified.

  In this specification, “9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component” means 9,9-bis (hydroxyalkoxyaryl) fluorene component and 9,9-bis (hydroxypolyalkoxyaryl) fluorene. All of the ingredients shall be included. "9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component" includes 9,9-bis (aryl-hydroxyalkoxyaryl) fluorene component and 9,9-bis (aryl-hydroxypolyalkoxyaryl). It does not include 9,9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene components such as fluorene components.

  In the present specification, the in-plane retardation measured in a specific wavelength region is represented by “R wavelength nm”. For example, R550 nm means an in-plane retardation measured at a wavelength of 550 nm.

1. Polyester resin The polyester resin of the present invention is a polyester resin containing a specific diol component (A) and a specific dicarboxylic acid component (B) as polymerization components.

(1) Diol component (A)
In the present invention, the diol component (A) includes at least a 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1). Thereby, while increasing glass transition temperature (Tg) and improving heat resistance, the phase difference film excellent in reverse wavelength dispersion can be provided.

9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1)
The 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) is not particularly limited, but the general formula (1):

Wherein Z ¹ and Z ² are the same or different and are each an aromatic hydrocarbon ring; R ^1a and R ^1b are the same or different and are each a substituted or unsubstituted carboxy group; R ^2a and R ^2b is the same or different and each is a divalent hydrocarbon group; n1 and n2 are the same or different and each is an integer of 0 to 4; m1 and m2 are the same or different and each is an integer of 1 or more. ]
The structural unit derived from the compound shown by these is mentioned.

In the general formula (1), the aromatic hydrocarbon ring represented by the rings Z ¹ and Z ² is not particularly limited, but includes not only a benzene ring but also a condensed polycyclic aromatic hydrocarbon ring [for example, A condensed bicyclic hydrocarbon ring (for example, a C _8-20 condensed bicyclic hydrocarbon ring such as an indene ring or a naphthalene ring, preferably a C _10-16 condensed bicyclic hydrocarbon ring), a condensed tricycle And condensed 2- to 4-cyclic hydrocarbon rings such as an anthracene ring (for example, anthracene ring, phenanthrene ring) and the like. The two rings Z ¹ and Z ² may be the same or different, but are preferably the same ring. As such rings Z ¹ and Z ² , a benzene ring and a naphthalene ring are preferable, and a benzene ring is more preferable, from the viewpoint of heat resistance, birefringence, and workability improvement effect. In the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1), it is preferable to use unsubstituted ones as the rings Z ¹ and Z ² .

In the general formula (1), the substituent that is not a (substituted or unsubstituted) carboxy group represented by the groups R ^1a and R ^1b may be a substituent that is not a carboxy group or a derivative group thereof (such as an alkoxycarbonyl group). Although not particularly limited, for example, a hydrocarbon group (alkyl group, cycloalkyl group, aryl group, aralkyl group, etc.), alkoxy group, cycloalkoxy group, aryloxy group, aralkyloxy group, acyl group, halogen atom, nitro group , A cyano group, an amino group, and the like. These substituents may have a substituent or may not have a substituent.

In the general formula (1), the alkyl group represented by the groups R ^1a and R ^1b is preferably a C _1-8 alkyl group, and more preferably a C _1-4 alkyl group. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and a t-butyl group. Examples of the substituent of the alkyl group include a hydrocarbon group (cycloalkyl group, aryl group, aralkyl group, etc.) described later, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, a halogen atom, It may have 1 or 2 such as nitro group, cyano group and the like.

In the general formula (1), the cycloalkyl group represented by the groups R ^1a and R ^1b is preferably a C _5-10 cycloalkyl group, more preferably a C _5-8 cycloalkyl group, and a C _5-6 cycloalkyl group. More preferred are groups. Specifically, a cyclopentyl group, a cyclohexyl group, etc. can be illustrated. Examples of the substituent of this cycloalkyl group include the hydrocarbon groups described above or below (alkyl groups, aryl groups, aralkyl groups, etc.), alkoxy groups, cycloalkoxy groups, aryloxy groups, aralkyloxy groups, acyl groups, halogens. It may have 1 or 2 atoms such as an atom, a nitro group, and a cyano group.

In the general formula (1), the aryl group represented by the groups R ^1a and R ^1b is preferably a C _6-10 aryl group. Specifically, phenyl group, alkylphenyl group (alkyl: those described above; methylphenyl group such as tolyl group, 2-methylphenyl group, 3-methylphenyl group, dimethylphenyl group such as xylyl group, etc.), naphthyl group Etc. can be illustrated. Examples of the substituent for the aryl group include the hydrocarbon groups described above or below (alkyl group, cycloalkyl group, aralkyl group, etc.), alkoxy groups, cycloalkoxy groups, aryloxy groups, aralkyloxy groups, acyl groups, halogens. It may have 1 or 2 atoms such as an atom, a nitro group, and a cyano group.

In the general formula (1), the aralkyl group represented by the groups R ^1a and R ^1b is preferably a C _7-14 aralkyl group having the above aryl group and the above alkyl group. Specific examples include a benzyl group and a phenethyl group. Examples of the substituent of the aralkyl group include a hydrocarbon group (alkyl group, cycloalkyl group, aryl group, etc.), alkoxy group, cycloalkoxy group, aryloxy group, aralkyloxy group, acyl group, halogen atom, nitro group. 1 or 2 such as a cyano group.

In the general formula (1), the alkoxy group represented by the groups R ^1a and R ^1b is preferably a C _1-8 alkoxy group, and more preferably a C _1-6 alkoxy group. Specific examples include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, an isobutoxy group, and a t-butoxy group. Examples of the substituent of the alkoxy group include a hydrocarbon group (alkyl group, cycloalkyl group, aryl group, aralkyl group, etc.), cycloalkoxy group, aryloxy group, aralkyloxy group, acyl group, halogen atom, nitro group. 1 or 2 such as a cyano group.

In the general formula (1), as the cycloalkoxy group represented by the groups R ^1a and R ^1b , a C _5-10 cycloalkoxy group is preferable. Specifically, a cyclohexyloxy group etc. can be illustrated. Examples of the substituent of the cycloalkoxy group include a hydrocarbon group (alkyl group, cycloalkyl group, aryl group, aralkyl group, etc.), alkoxy group, aryloxy group, aralkyloxy group, acyl group, halogen atom, nitro group. 1 or 2 such as a cyano group.

In the general formula (1), the aryloxy group represented by the groups R ^1a and R ^1b is preferably a C _6-10 aryloxy group having the aryl group described above. Specifically, a phenoxy group etc. can be illustrated. Examples of the substituent of the aryloxy group include a hydrocarbon group (alkyl group, cycloalkyl group, aryl group, aralkyl group, etc.), alkoxy group, cycloalkoxy group, aralkyloxy group, acyl group, halogen atom, nitro group. 1 or 2 such as a cyano group.

In the general formula (1), the aralkyloxy group represented by the groups R ^1a and R ^1b is preferably a C _7-14 aralkyloxy group having the aforementioned aryl group and the aforementioned alkyloxy group. Specifically, a benzyloxy group etc. can be illustrated. Examples of the substituent of the aralkyloxy group include a hydrocarbon group (alkyl group, cycloalkyl group, aryl group, aralkyl group, etc.), alkoxy group, cycloalkoxy group, aryloxy group, acyl group, halogen atom, nitro group. 1 or 2 such as a cyano group.

In the general formula (1), the acyl group represented by the groups R ^1a and R ^1b is preferably a C _1-6 acyl group. Specifically, an acetyl group etc. can be illustrated. Examples of the substituent of the acyl group include a hydrocarbon group (alkyl group, cycloalkyl group, aryl group, aralkyl group, etc.), alkoxy group, cycloalkoxy group, aryloxy group, aralkyloxy group, halogen atom, nitro group. 1 or 2 such as a cyano group.

In the general formula (1), examples of the halogen atom represented by the groups R ^1a and R ^1b include a fluorine atom, a chlorine atom, and a bromine atom.

In the general formula (1), the amino groups represented by the groups R ^1a and R ^1b include hydrocarbon groups (alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, etc.), alkoxy groups, cycloalkoxy groups, aryloxy groups. It may have 1 to 2 substituents such as a group, an aralkyloxy group, an acyl group, a halogen atom, a nitro group, and a cyano group. Specific examples of the amino group include an amino group and a dialkylamino group such as a dimethylamino group.

Among these, as the groups R ^1a and R ^1b , the polymerization efficiency and the birefringence improvement effect (particularly the effect of increasing the in-plane retardation) with a dicarboxylic acid component (particularly a dicarboxylic acid component (B1) having a fluorene skeleton) to be described later. ) And the like, it is preferable to employ a compatible substituent.

In addition, when n1 is plural (an integer of 2 to 4), the plural groups R ^1a may be the same or different from each other. Similarly, when n2 is plural (an integer of 2 to 4), the plural groups R ^1b may be the same or different from each other.

Further, the group R ^1a and the group R ^1b substituted on different benzene rings may be the same or different from each other. Further, the bonding position (substitution position) of the groups R ^1a and R ^1b is not particularly limited, and examples thereof include at least one of the 2-position and 7-position of the fluorene ring.

In the general formula (1), n1 and n2 which are the number of substitutions of the groups R ^1a and R ^1b may be the same or different, but each is preferably an integer of 0 to 4, more preferably an integer of 0 to 2, 0 or 1 is more preferable, and 0 is particularly preferable.

In the general formula (1), examples of the divalent hydrocarbon group represented by the groups R ^2a and R ^2b include an aliphatic hydrocarbon group (an alkylene group (or alkylidene group), a cycloalkylene group, an alkylene (or alkylidene). ) -Cycloalkylene group, bi- or tricycloalkylene group, etc.), aromatic hydrocarbon group (arylene group, alkylene (or alkylidene) -arylene group, etc.) and the like.

In the general formula (1), the alkylene group (or alkylidene group) represented by the groups R ^2a and R ^2b is preferably an alkylene group, more preferably a C _1-8 alkylene group, and even more preferably a C _1-4 alkylene group. , C _2-4 alkylene groups are particularly preferred, and C _2-3 alkylene groups are most preferred. Specifically, methylene group, ethylene group, ethylidene group, trimethylene group, propylene group, propylidene group, tetramethylene group, ethylethylene group, butane-2-ylidene group, 1,2-dimethylethylene group, pentamethylene group, Examples include pentane-2,3-diyl group.

In the general formula (1), the cycloalkylene group represented by the groups R ^2a and R ^2b is preferably a C _5-10 cycloalkylene group, and more preferably a C _5-8 cycloalkylene group. Specific examples include a cyclopentylene group, a cyclohexylene group, a methylcyclohexylene group, and a cycloheptylene group.

In the general formula (1), the alkylene (or alkylidene) -cycloalkylene group represented by the groups R ^2a and R ^2b is preferably an alkylene-cycloalkylene group, and a C _1-6 alkylene-C _5-10 cycloalkylene group is More preferred is a C _1-4 alkylene-C _5-8 cycloalkylene group. Specific examples include a methylene-cyclohexylene group, an ethylene-cyclohexylene group, an ethylene-methylcyclohexylene group, and an ethylidene-cyclohexylene group.

In the general formula (1), specific examples of the bi- or tricycloalkylene group represented by the groups R ^2a and R ^2b include a norbornane-diyl group.

In the general formula (1), the arylene group represented by the groups R ^2a and R ^2b is preferably a C _6-10 arylene group. Specific examples include a phenylene group and a naphthalenediyl group.

In the general formula (1), the alkylene (or alkylidene) -arylene group represented by the groups R ^2a and R ^2b is preferably an alkylene-arylene group, more preferably a C _1-6 alkylene-C _6-20 arylene group, A C _1-4 alkylene-C _6-10 arylene group is more preferred, and a C _1-2 alkylene-phenylene group is particularly preferred. Specific examples include a methylene-phenylene group, an ethylene-phenylene group, an ethylene-methylphenylene group, and an ethylidenephenylene group.

Among these, a divalent aliphatic hydrocarbon group, particularly an alkylene group (for example, a C _1-4 alkylene group such as a methylene group or an ethylene group) is preferable.

  The alkylene (or alkylidene) -cycloalkylene group and the alkylene (alkylidene) -arylene group are -Ra-Rb- (wherein Ra is bonded to the 9th position of the hydroxy group or fluorene in the general formula (1)). An alkylene group or an alkylidene group, and Rb represents a cycloalkylene group or an arylene group).

In addition, when m1 is plural (an integer of 2 or more), the plural groups R ^2a may be the same or different from each other. Similarly, when m2 is plural (an integer of 2 or more), the plural groups R ^2b may be the same or different from each other.

Further, the group R ^2a and the group R ^2b may be the same or different from each other.

In the general formula (1), m1 and m2 which are the repeating numbers of OR ^2a and OR ^2b may be the same or different, but each is preferably an integer of 1 or more, more preferably an integer of 1 to 10, An integer of 6 is more preferred, an integer of 1-4 is particularly preferred, an integer of 1-2 is more preferred, and 1 is most preferred.

In the general formula (1), the substitution positions of the —O— (R ^2a O) _m1 —H group and the —O— (R ^2b O) _m2 —H group are not particularly limited, and the rings Z ¹ and Z ^It only has to be substituted at an appropriate substitution position of ² . For example, the —O— (R ^2a O) _m1 —H group and the —O— (R ^2b O) _m2 —H group are in positions 2 to 6 of the benzene ring when the rings Z ¹ and Z ² are benzene rings. It may be substituted, and is preferably substituted at the 4-position. In addition, the —O— (R ^2a O) _m1 —H group and the —O— (R ^2b O) _m2 —H group are a condensed polycyclic ring when the rings Z ¹ and Z ² are condensed polycyclic hydrocarbon rings. In the formula hydrocarbon ring, it is often substituted at least with a hydrocarbon ring different from the hydrocarbon ring bonded to the 9th position of fluorene (for example, the 5th and 6th positions of the naphthalene ring).

The compound represented by the general formula (1) includes a compound in which n1 and n2 are 0. Such compounds, in the general formula (1), are both benzene rings ^{Z 1} and ^{Z 2,} m1 and m2 is at both 1 9,9-bis (hydroxyalkoxy phenyl) fluorene; ^{Z 1} and 9,9-bis (hydroxypolyalkoxyphenyl) fluorene in which both Z ² are benzene rings and m 1 and m 2 are 2 or more; both Z ¹ and Z ² are naphthalene rings, and both m 1 and m 2 are 1 There may be mentioned 9,9-bis (hydroxyalkoxynaphthyl) fluorene.

Examples of 9,9-bis (hydroxyalkoxyphenyl) fluorene include 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene and 9,9-bis [4- (2-hydroxypropoxy) phenyl]. 9,9-bis (hydroxyC _2-4 alkoxyphenyl) fluorene such as fluorene and the like can be mentioned.

As 9,9-bis (hydroxypolyalkoxyphenyl) fluorene, for example, 9,9-bis (hydroxydialkoxyphenyl) fluorene and the like are preferable, for example, 9,9-bis {4- [2- (2-hydroxy) ethoxy) ethoxy] 9,9-bis _{(hydroxy-di-C 2-4} alkoxyphenyl) fluorene phenyl} fluorene, and the like.

Examples of 9,9-bis (hydroxyalkoxynaphthyl) fluorene include 9,9-bis [6- (2-hydroxyethoxy) -2-naphthyl] fluorene and 9,9-bis [6- (2-hydroxypropoxy). ) -2-naphthyl] fluorene such as 9,9-bis (hydroxy _{C 2-4} alkoxy naphthyl), and fluorene and the like.

Among these, as the compound represented by the general formula (1), 9,9-bis (hydroxyalkoxyphenyl) fluorene is particularly preferable, and 9,9-bis (hydroxyC _2-4 alkoxyphenyl) fluorene is more preferable. 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene and the like are more preferable. That is, as the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1), a structural unit derived from 9,9-bis (hydroxyalkoxyphenyl) fluorene is preferable, and 9,9-bis (hydroxyC _2). The structural unit derived from _-4 alkoxyphenyl) fluorene is more preferable, and the structural unit derived from 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene is more preferable.

  In the diol component (A) of the polyester resin of the present invention, the content of the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) is heat resistant with a glass transition temperature (Tg) in a more appropriate range. From the viewpoint of improving the properties and processability, and obtaining a retardation film having more excellent reverse wavelength dispersion, the amount is preferably 40 mol% or more, more preferably 50 to 98 mol%, based on the entire diol component (A). Preferably, 60 to 95 mol% is more preferable, 70 to 90 mol% is particularly preferable, and 75 to 83 mol% is most preferable.

Aliphatic diol component (A2)
The diol component (A) of the polyester resin of the present invention may be composed only of the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1), but the aliphatic diol component (A2) May be included. By including the aliphatic diol component (A2), it is possible to improve the processability and more efficiently polymerize the polyester resin while maintaining heat resistance, birefringence and reverse wavelength dispersion. This aliphatic diol component (A2) can also be a solvent for the synthesis of the polyester resin of the present invention.

  Examples of the aliphatic diol component (A2) include a chain aliphatic diol component (alkane diol component, polyalkane diol component, etc.), an alicyclic diol component (cycloalkane diol component, di (hydroxyalkyl) cyclohexane. Alkane component, isosorbide component, etc.).

As the alkanediol, a C _2-10 alkanediol is preferable, a C _2-6 alkanediol is more preferable, and a C _2-4 alkanediol is further preferable. Specifically, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 1,4-pentanediol, 1,5-pentanediol, 1,3-pentanediol, neopentyl glycol and the like can be mentioned.

The polyalkanediol is preferably di- or tri-C _2-4 alkanediol. Specific examples include diethylene glycol, dipropylene glycol, and triethylene glycol.

As the cycloalkanediol, C _5-8 cycloalkanediol is preferable. Specifically, cyclohexanediol etc. are mentioned.

As the di (hydroxyalkyl) cycloalkane, di (hydroxyC _1-4 alkyl) C _5-8 cycloalkane is preferable. Specific examples include cyclohexanedimethanol.

  These aliphatic diol components (A2) may be used alone or in combination of two or more.

Among these, as the aliphatic diol component (A2), from the viewpoint of further improving the processability and more efficiently performing polymerization of the polyester resin while maintaining heat resistance, birefringence and reverse wavelength dispersion more. In particular, low molecular weight aliphatic diol components (chain aliphatic diol components) such as alkane diols (particularly C _2-4 alkane diols such as ethylene glycol) can be suitably used.

  In the diol component (A) of the polyester resin of the present invention, the content of the aliphatic diol component (A2) further improves processability while maintaining heat resistance, birefringence and reverse wavelength dispersibility. From the viewpoint that the polymerization of the resin can be performed more efficiently, it is 60 mol% or less, preferably 2 to 50 mol%, more preferably 5 to 40 mol%, and still more preferably based on the entire diol component (A). It can be 10 to 30 mol%, particularly preferably 17 to 25 mol%.

  The ratio of the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) and the aliphatic diol component (A2) is, for example, the former / the latter (molar ratio) = 40/60 to 100/0. Preferably, 50/50 to 98/2 is more preferable, 60/40 to 95/5 is still more preferable, 70/30 to 90/10 is particularly preferable, and 75/25 to 83/17 is most preferable. Thereby, processability can be improved more and polymerization of a polyester resin can be performed more efficiently, maintaining heat resistance, birefringence, and reverse wavelength dispersion more.

  In the diol component (A), the total amount of the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) and the aliphatic diol component (A2) is heat resistance, birefringence and reverse wavelength dispersion. Is more preferably 50 mol% or more (50 to 100 mol%) with respect to the entire diol component (A), from the viewpoint of further improving processability and more efficiently polymerizing the polyester resin, while maintaining 60%. More preferably mol% or more (60-100 mol%), more preferably 70 mol% or more (70-100 mol%), particularly preferably 80 mol% or more (80-100 mol%), 90 mol% or more (90 ~ 100 mol%) is most preferred.

In the other diol component diol component (A), as long as the effects of the present invention are not impaired, the other diol component (9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) and aliphatic A diol component not belonging to the category of the diol component (A2) may be included.

  Examples of such other diol components include 9,9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene component (A3) and aromatic diol component (A4). These other diol components may be used alone or in combination of two or more.

  The 9,9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene component (A3) is not particularly limited, but is typically represented by the general formula (2):

[Wherein Z ¹ , Z ² , R ^1a , R ^1b , R ^2a , R ^2b , n1, n2, m1 and m2 are the same as above; R ^3a and R ^3b are the same or different and each has a substituent. Aryl groups which may be substituted; k1 and k2 are the same or different and each is an integer of 1 or more. ]
The structural unit derived from the compound shown by these is mentioned.

In the general formula (2), Z ¹ , Z ² , R ^1a , R ^1b , R ^2a , R ^2b , n1, n2, m1 and m2 are the same as described above. The same applies to preferred embodiments.

In the general formula (2), the aryl group represented by the groups R ^3a and R ^3b is preferably a C _6-10 aryl group. Specifically, phenyl group, alkylphenyl group (alkyl: those described above; methylphenyl group such as tolyl group, 2-methylphenyl group, 3-methylphenyl group, dimethylphenyl group such as xylyl group, etc.), naphthyl group Etc. can be illustrated. Examples of the substituent for the aryl group include the hydrocarbon groups described above or below (alkyl group, cycloalkyl group, aralkyl group, etc.), alkoxy groups, cycloalkoxy groups, aryloxy groups, aralkyloxy groups, acyl groups, halogens. It may have 1 or 2 atoms such as an atom, a nitro group, and a cyano group.

In addition, when k1 is plural (an integer of 2 or more), the plural groups R ^3a may be the same or different from each other. Similarly, when k2 is plural (an integer of 2 or more), the plural groups R ^3b may be the same or different from each other.

The group R ^3a and the group R ^3b may be the same or different from each other.

In the general formula (2), k1 and k2 which are the number of substitutions of the groups R ^3a and R ^3b may be the same or different, but each is preferably an integer of 1 or more, more preferably an integer of 1 to 8; An integer of -4 is more preferable, an integer of 1-3 is particularly preferable, an integer of 1-2 is more preferable, and 1 is most preferable.

Incidentally, in the general formula (2), the substitution position of the group R ^3a and R ^3b are not particularly limited, as long as the replaced with appropriate substitution position of the ring Z ¹ and Z ^2. For example, when the rings Z ¹ and Z ² are benzene rings, the groups R ^3a and R ^3b may be substituted at the 2-6 positions of the benzene ring and may be substituted at the 3-position or 5-position. preferable. In addition, when the rings Z ¹ and Z ² are condensed polycyclic hydrocarbon rings, the groups R ^3a and R ^3b are different from the hydrocarbon ring bonded to the 9-position of fluorene in the condensed polycyclic hydrocarbon ring. In most cases (for example, the 5-position, the 7-position, the 8-position, etc. of the naphthalene ring).

Typical 9,9-bis (aryl-hydroxy (poly) alkoxyaryl) fluorene (A3) (or a compound represented by the general formula (2)) includes, for example, a compound in which n1 and n2 are 0. It is. As such a compound, 9,9-bis (aryl-hydroxyalkoxyphenyl) fluorene in which Z ¹ and Z ² are both benzene rings and m 1 and m ² are both ¹ in the general formula (2); Examples include 9,9-bis (aryl-hydroxypolyalkoxyphenyl) fluorene, wherein ¹ and Z ² are both benzene rings, and both m1 and m2 are 2 or more.

Examples of 9,9-bis (aryl-hydroxyalkoxyphenyl) fluorene include 9,9-bis [4- (2-hydroxyethoxy) -3-phenylphenyl] fluorene and 9,9-bis [4- (2 9,9-bis (mono- or di-C _6-10 aryl-hydroxy C _2-4 alkoxyphenyl) fluorene such as -hydroxypropoxy) -3-phenylphenyl] fluorene.

As 9,9-bis (aryl-hydroxypolyalkoxyphenyl) fluorene, for example, 9,9-bis (aryl-hydroxydialkoxyphenyl) fluorene is preferable, and for example, 9,9-bis {4- [2- And 9,9-bis (mono or diC _6-10 aryl-hydroxydiC _2-4 alkoxyphenyl) fluorene such as (2-hydroxyethoxy) ethoxy] -3-phenylphenyl} fluorene.

Of these, 9,9-bis (aryl-hydroxyalkoxyphenyl) fluorene is particularly preferable as the compound represented by the general formula (2), and 9,9-bis (C _6-10 aryl-hydroxy C ₂ -2) is preferable. _4- alkoxyphenyl) fluorene is more preferable, and 9,9-bis [4- (2-hydroxyethoxy) -3-phenylphenyl] fluorene is more preferable. That is, as the 9,9-bis (aryl-hydroxy (poly) alkoxyphenyl) fluorene component (A3), a structural unit derived from 9,9-bis (aryl-hydroxyalkoxyphenyl) fluorene is preferable, and 9,9-bis A structural unit derived from (C _6-10 aryl- _{hydroxyC 2-4} alkoxyphenyl) fluorene is more preferable, and a structural unit derived from 9,9-bis [4- (2-hydroxyethoxy) -3-phenylphenyl] fluorene is Further preferred.

  The aromatic diol component (A4) is not particularly limited, but is a dihydroxyarene component, an araliphatic diol component, a biphenol / bisphenol component, a 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) and 9 , 9-bis (aryl-hydroxy (poly) alkoxyphenyl) fluorene component (A3) diol component having a fluorene skeleton that does not belong to the category.

  Examples of dihydroxyarene include hydroquinone and resorcinol.

Examples of the araliphatic diol include di (hydroxy C _1-4 alkyl) C _6-10 arenes such as 1,4-benzenedimethanol and 1,3-benzenedimethanol.

Examples of biphenol and bisphenol include biphenol and bis (hydroxyphenyl) C _1-10 alkane such as bisphenol A.

As a diol having a fluorene skeleton that does not belong to the category of 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) and 9,9-bis (aryl-hydroxy (poly) alkoxyphenyl) fluorene component (A3) Is preferably 9,9-bis (alkyl-hydroxyalkoxyaryl) fluorene, specifically, 9,9-bis [4- (2-hydroxyethoxy) -3-methylphenyl] fluorene, 9,9-bis such as 9-bis [4- (2-hydroxypropoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3,5-dimethylphenyl] fluorene (mono- or _{di-C 1-4} alkyl - hydroxy _{C 2-4} alkoxyphenyl) fluorene), and the like .

  These other diol components (9,9-bis (aryl-hydroxy (poly) alkoxyphenyl) fluorene component (A3) and aromatic diol component (A4)) may be used alone or in combination of two or more. May be used.

  When other diol components are included, the content of the other diol components further improves processability while maintaining heat resistance, birefringence and reverse wavelength dispersibility, and makes it possible to more efficiently polymerize the polyester resin. To 50 mol% or less (0 to 50 mol%), more preferably 40 mol% or less (0 to 40 mol%), and more preferably 30 mol% or less (0 to 30 mol%) based on the entire diol component (A). %) Is more preferable, 20 mol% or less (0 to 20 mol%) is particularly preferable, and 10 mol% or less (0 to 10 mol%) is most preferable.

  If necessary, in addition to the diol component (A), a small amount of an alkane polyol component such as glycerin, trimethylolpropane, trimethylolethane, pentaerythritol may be used as a polyol component having three or more hydroxy groups. Good. When these polyol components having three or more hydroxy groups are used, they are 10 mol% or less (for example, 0.1 to 8 mol%, preferably, based on the total amount of the diol component (A) and the polyol component. Can be about 0.2 to 5 mol%).

(2) Dicarboxylic acid component (B)
In the present invention, the dicarboxylic acid component (B) includes at least a dicarboxylic acid component (B1) having a fluorene skeleton. Thereby, the retardation film excellent in reverse wavelength dispersion can be provided, maintaining a glass transition temperature (Tg) and maintaining heat resistance and workability.

Dicarboxylic acid component having a fluorene skeleton (B1)
The dicarboxylic acid component (B1) having a fluorene skeleton includes both a dicarboxylic acid component having a fluorene skeleton and a dicarboxylic acid ester-forming derivative component having a fluorene skeleton.

  The ester-forming derivative is not particularly limited, and examples thereof include esters, acid halides, and acid anhydrides.

As an ester, for example, an alkyl ester is preferable, a C _1-4 alkyl ester is more preferable, and a C _1-2 alkyl ester is more preferable. Specific examples include methyl esters and ethyl esters.

  As an acid halide, an acid chloride etc. can be illustrated, for example.

  The ester-forming derivative may be a monoester (half ester) -forming derivative or a diester-forming derivative.

  The dicarboxylic acid component having such a fluorene skeleton can be appropriately selected according to the method for producing the polyester resin to be obtained. However, when the melt polymerization method is employed, the dicarboxylic acid having a fluorene skeleton, the fluorene skeleton In many cases, a dicarboxylic acid ester or the like (particularly a dicarboxylic acid ester having a fluorene skeleton) is used (the same applies hereinafter).

  The dicarboxylic acid having a fluorene skeleton may be a compound in which two carboxy group-containing groups are substituted on two benzene rings constituting fluorene, such as fluorene carboxylic acid (2,7-dicarboxyfluorene and the like). However, usually, a compound in which two carboxy group-containing groups are substituted at the 9-position of fluorene can be suitably used.

  When such a compound is used in combination with the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1), the glass transition temperature (Tg) and the birefringence are further maintained, while the reverse A retardation film having better wavelength dispersion can be provided.

  Specifically, the compound in which two carboxy group-containing groups are substituted at the 9-position of the fluorene is represented by the general formula (3):

[Wherein R ^4a and R ^4b are the same or different and each is a (substituted or unsubstituted) substituent that is not a carboxy group; R ^5a and R ^5b are the same or different and are each a divalent hydrocarbon group; j2 is the same or different and is an integer of 0 to 4, respectively. ]
The compound shown by these is preferable.

  That is, the dicarboxylic acid component (B1) having a fluorene skeleton is preferably a compound represented by the general formula (3) or a structural unit derived from an ester, acid halide or acid anhydride thereof.

In general formula (3), R ^4a and R ^4b may be any substituents that are not (substituted or unsubstituted) carboxy groups, but the same as R ^1a and R ^1b can be used. .

The groups R ^4a and R ^4b are compatible with the diol component (particularly 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1)) in consideration of the polymerization efficiency, the effect of improving the reverse wavelength dispersion, and the like. It is preferable to employ a good substituent.

In addition, when j1 is plural (an integer of 2 to 4), the plural groups R ^4a may be the same or different from each other. Similarly, when j2 is plural (an integer of 2 to 4), the plural groups R ^4b may be the same or different from each other.

Further, the groups R ^4a and R ^4b substituted on different benzene rings may be the same or different from each other. In addition, the bonding position (substitution position) of the groups R ^4a and R ^4b is not particularly limited, and examples thereof include at least one of the 2nd and 7th positions of the fluorene ring.

In the general formula (3), j1 and j2 which are the number of substitutions of the groups R ^4a and R ^4b may be the same or different, but each is preferably an integer of 0 to 4, more preferably an integer of 0 to 2, 0 or 1 is more preferable, and 0 is particularly preferable.

In the general formula (3), R ^5a and R ^5b may be any divalent hydrocarbon group, but the same as R ^2a and R ^2b can be used. The same applies to preferred embodiments.

Further, the group R ^5a and the group R ^5b may be the same or different from each other.

Incidentally, in the general formula ^(3), the substitution position of -R 5a COOH group and ^-R 5b COOH group is not particularly limited, as long as the replaced with appropriate substitution position of the ring ^{Z 1} and ^{Z 2.} For example, when the rings Z ¹ and Z ² are benzene rings, the —R ^5a COOH group and the —R ^5b COOH group may be substituted at the 2-6 position of the benzene ring, and are substituted at the 4 position. Is preferred. The —R ^5a COOH group and the —R ^5b COOH group are a carbon atom bonded to the 9th position of fluorene in the condensed polycyclic hydrocarbon ring when the rings Z ¹ and Z ² are condensed polycyclic hydrocarbon rings. In many cases, at least a hydrocarbon ring other than the hydrogen ring is substituted (for example, the 5-position, 6-position, etc. of the naphthalene ring).

Examples of the dicarboxylic acid having a fluorene skeleton represented by the general formula (3) include compounds in which the groups R ^5a and R ^5b are divalent aliphatic hydrocarbon groups. For example, 9,9-bis (carboxyalkyl) fluorene, 9,9-bis (carboxycycloalkyl) fluorene and the like can be mentioned.

As the 9,9-bis (carboxyalkyl) fluorene, 9,9-bis (carboxyC _1-6 alkyl) fluorene is preferable. Specifically, 9,9-bis (carboxymethyl) fluorene, 9,9-bis (2-carboxyethyl) fluorene, 9,9-bis (1-carboxyethyl) fluorene, 9,9-bis (1- Carboxypropyl) fluorene, 9,9-bis (2-carboxypropyl) fluorene, 9,9-bis (2-carboxy-1-methylethyl) fluorene, 9,9-bis (2-carboxy-1-methylpropyl) Examples include fluorene, 9,9-bis (2-carboxybutyl) fluorene, 9,9-bis (2-carboxy-1-methylbutyl) fluorene, 9,9-bis (5-carboxypentyl) fluorene, and the like.

As the 9,9-bis (carboxycycloalkyl) fluorene, 9,9-bis (carboxyC _5-8 cycloalkyl) fluorene is preferable. Specific examples include 9,9-bis (carboxycyclohexyl) fluorene.

  These compounds represented by the general formula (3) may be used alone or in combination of two or more.

Of these, 9,9-bis (carboxyalkyl) fluorene is preferable, and 9,9-bis (carboxyC _1-4 alkyl) fluorene is more preferable. That is, as the dicarboxylic acid component (B1) having a fluorene skeleton, 9,9-bis (carboxyalkyl) fluorene, or a structural unit derived from an ester, acid halide, or acid anhydride thereof is preferable, and 9,9-bis ( A structural unit derived from carboxy C _1-4 alkyl) fluorene, or an ester, acid halide, or acid anhydride thereof is more preferable.

  In the dicarboxylic acid component (B) possessed by the polyester resin of the present invention, the content of the dicarboxylic acid component (B1) having a fluorene skeleton is due to the reverse wavelength dispersion while maintaining the glass transition temperature (Tg) and birefringence more. From the viewpoint of obtaining an excellent retardation film, it is preferably 5 mol% or more, more preferably 7 to 50 mol%, still more preferably 8 to 40 mol%, more preferably 10 to 30 mol based on the entire dicarboxylic acid component (B). % Is particularly preferable, and 12 to 20 mol% is most preferable. In order to further improve the birefringence (in-plane retardation), the content of the dicarboxylic acid component (B1) having a fluorene skeleton is 8 to 18 mol% with respect to the entire dicarboxylic acid component (B). It is preferable to do it, and it is more preferable to set it as 12-17 mol%. In order to further improve the reverse wavelength dispersion (to further reduce the in-plane retardation wavelength dispersion), the content of the dicarboxylic acid component (B1) having a fluorene skeleton is added to the entire dicarboxylic acid component (B). On the other hand, it is preferable to set it as 13-27 mol%, and it is more preferable to set it as 18-23 mol%.

Non-fluorene aromatic dicarboxylic acid component (B2)
In the present invention, the dicarboxylic acid component (B) may contain a non-fluorene aromatic dicarboxylic acid component (B2) in addition to the dicarboxylic acid component (B1) having a fluorene skeleton. In this way, by combining the dicarboxylic acid component (B1) having a fluorene skeleton and the non-fluorene aromatic dicarboxylic acid component (B2), the glass transition temperature (Tg) is increased to improve the processability and the polymerization efficiency of the polyester resin. While maintaining the heat resistance, it is possible to further improve the heat resistance, maintain the reverse wavelength dispersion, and further improve the birefringence.

  Examples of the non-fluorene aromatic dicarboxylic acid component (B2) include a monocyclic aromatic dicarboxylic acid component and a non-fluorene polycyclic aromatic dicarboxylic acid component.

  Examples of the monocyclic aromatic dicarboxylic acid component include a structural unit derived from a monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof (the ester-forming derivative is as described above).

As the monocyclic aromatic dicarboxylic acid, C _6-10 arene dicarboxylic acid is preferable. Specifically, terephthalic acid, alkyl terephthalic acid (C _1-4 alkyl terephthalic acid such as 5-methyl terephthalic acid) isophthalic acid, alkyl isophthalic acid (C _1-4 alkyl isophthalic acid such as 4-methyl isophthalic acid), etc. Can be illustrated.

  Among these monocyclic aromatic dicarboxylic acids, from the viewpoint of further increasing the glass transition temperature (Tg) to further improve the heat resistance and further improve the birefringence, a symmetric monocyclic aromatic dicarboxylic acid. Alternatively, as the ester-forming derivative thereof, terephthalic acid and / or an ester-forming derivative thereof is preferable.

  On the other hand, an asymmetric monocyclic aromatic dicarboxylic acid is preferable from the viewpoint of further reducing the glass transition temperature (Tg) to improve the workability and the polymerization efficiency of the polyester resin and to maintain the reverse wavelength dispersibility. Further, by combining the asymmetric monocyclic aromatic dicarboxylic acid with the dicarboxylic acid component (B1) having a fluorene skeleton, the hygroscopic property of the polyester resin can be further suppressed.

Examples of such asymmetric monocyclic aromatic dicarboxylic acids include phthalic acid, isophthalic acid, alkylisophthalic acid ( _C1-4 alkylisophthalic acid such as 4-methylisophthalic acid), alkyl terephthalic acid (5-methylterephthalic acid) C _1-4 alkyl terephthalic acid) and the like.

  These asymmetric monocyclic aromatic dicarboxylic acids may be used alone or in combination of two or more.

  Examples of the non-fluorene polycyclic aromatic dicarboxylic acid component include a structural unit derived from non-fluorene polycyclic aromatic dicarboxylic acid or an ester-forming derivative thereof (the ester-forming derivative is as described above).

  The non-fluorene polycyclic aromatic dicarboxylic acid is not particularly limited as long as it is a dicarboxylic acid that does not have a fluorene skeleton as the polycyclic aromatic skeleton, and examples thereof include condensed polycyclic aromatic dicarboxylic acids, arylarene dicarboxylic acids, Examples thereof include diarylalkane dicarboxylic acid and diaryl ketone dicarboxylic acid.

Examples of the condensed polycyclic aromatic dicarboxylic acid include 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, and 2,6-naphthalene. Naphthalenedicarboxylic acid having two carboxyl groups in different rings such as dicarboxylic acid; naphthalenedicarboxylic acid having two carboxyl groups in the same ring such as 1,2-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid; anthracene dicarboxylic acid Condensed polycyclic C _10-24 arene-dicarboxylic acid such as acid and phenanthrene dicarboxylic acid (especially condensed polycyclic C _10-16 arene-dicarboxylic acid, and further condensed polycyclic C _10-14 arene-dicarboxylic acid), etc. Can be illustrated.

The arylarene dicarboxylic acid is preferably a C _6-10 aryl C _6-10 arene dicarboxylic acid, and examples thereof include biphenyl dicarboxylic acids such as 2,2′-biphenyl dicarboxylic acid and 4,4′-biphenyl dicarboxylic acid. .

  As the diarylalkane dicarboxylic acid, diC6-10 aryl C1-6 alkane-dicarboxylic acid is preferable, and diphenyl C1-4 alkane-dicarboxylic acid is more preferable. Specific examples include diphenylalkanedicarboxylic acids such as 4,4'-diphenylmethanedicarboxylic acid.

The diaryl ketone dicarboxylic acid is preferably diC _6-10 aryl ketone-dicarboxylic acid, and specific examples thereof include diphenyl ketone dicarboxylic acid such as 4,4′-diphenyl ketone dicarboxylic acid.

  These non-fluorene polycyclic aromatic dicarboxylic acids may be used alone or in combination of two or more.

  Among these non-fluorene polycyclic aromatic dicarboxylic acid components, in particular, the glass transition temperature (Tg) is raised to improve the heat resistance while maintaining the processability and the polymerization efficiency of the polyester resin, and the reverse wavelength dispersion From the viewpoint of maintaining the properties and improving the birefringence, condensed polycyclic aromatic dicarboxylic acids are preferable, and naphthalenedicarboxylic acid is more preferable.

  In addition, you may combine said monocyclic aromatic dicarboxylic acid and non-fluorene polycyclic aromatic dicarboxylic acid.

  When the dicarboxylic acid component (B1) having a fluorene skeleton and the non-fluorene aromatic dicarboxylic acid component (B2) are used in combination, the content of the non-fluorene aromatic dicarboxylic acid component (B2) is more than the glass transition temperature (Tg). From the viewpoint of further improving heat resistance while maintaining processability and polymerization efficiency of the polyester resin, and increasing reverse birefringence and further improving birefringence, the dicarboxylic acid component (B) as a whole 95 mol% or less, more preferably 50 to 93 mol%, still more preferably 60 to 92 mol%, particularly preferably 70 to 90 mol%, and most preferably 80 to 88 mol%.

  In addition, a symmetric monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof is used as the non-fluorene aromatic dicarboxylic acid component (B2) (configuration derived from a symmetric monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof) When the unit is included), the content of the symmetric monocyclic aromatic dicarboxylic acid or its ester-forming derivative increases the glass transition temperature (Tg) to maintain processability and the polymerization efficiency of the polyester resin. However, from the viewpoint of further improving heat resistance, maintaining reverse wavelength dispersion, and further improving birefringence (particularly in-plane retardation), 62 to 75 mol% is preferable, and 67 to 72 mol% is more preferable. .

  On the other hand, an asymmetric monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof is used as the non-fluorene aromatic dicarboxylic acid component (B2) (configuration derived from an asymmetric monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof) When the unit is included), the content of the asymmetric monocyclic aromatic dicarboxylic acid or its ester-forming derivative increases the glass transition temperature (Tg) to maintain the processability and the polymerization efficiency of the polyester resin. However, from the viewpoints of further improving heat resistance, maintaining reverse wavelength dispersion and further improving birefringence, 82 to 92 mol% is preferable, and 83 to 87 mol% is more preferable.

  The ratio of the dicarboxylic acid component (B1) having a fluorene skeleton and the non-fluorene aromatic dicarboxylic acid component (B2) is preferably the former / the latter (molar ratio) = 5 / 95-100 / 0, and 7 / 93-50 / 50 is more preferable, 8/92 to 40/60 is more preferable, 10/90 to 30/70 is particularly preferable, and 12/88 to 20/80 is most preferable. In addition, a symmetric monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof is used as the non-fluorene aromatic dicarboxylic acid component (B2) (configuration derived from a symmetric monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof) In the case of including a unit), the ratio of the dicarboxylic acid component (B1) having a fluorene skeleton to the symmetric monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof is the former / the latter (molar ratio) = 25 / 75-38 / 62 is preferable and 28 / 72-33 / 67 is more preferable. Also, an asymmetric monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof is used as the non-fluorene aromatic dicarboxylic acid component (B2) (configuration derived from an asymmetric monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof) In the case of including a unit), the ratio of the dicarboxylic acid component (B1) having a fluorene skeleton to the asymmetric monocyclic aromatic dicarboxylic acid or an ester-forming derivative thereof is the former / the latter (molar ratio) = 8 / 92-18 / 82 is preferable and 13 / 87-17 / 83 is more preferable.

Other dicarboxylic acid component The dicarboxylic acid component (B) may further contain other dicarboxylic acid components as long as the effects of the present invention are not impaired.

  Other dicarboxylic acid components (dicarboxylic acid components not belonging to the category of dicarboxylic acid component (B1) having a fluorene skeleton and non-fluorene aromatic dicarboxylic acid component (B2)) include, for example, aliphatic dicarboxylic acid components (B3), An alicyclic dicarboxylic acid component (B4) etc. are mentioned.

The aliphatic dicarboxylic acid is preferably an alkanedicarboxylic acid, and examples thereof include C _2-12 alkanedicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and decanedicarboxylic acid.

Examples of the alicyclic dicarboxylic acid include cycloalkane dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid (particularly C _5-10 cycloalkane-dicarboxylic acid), decalin dicarboxylic acid, norbornane dicarboxylic acid, adamantane dicarboxylic acid, and tricyclohexane. Examples thereof include di- or tricycloalkane dicarboxylic acids such as decanedicarboxylic acid.

  That is, as other dicarboxylic acid components, structural units derived from these dicarboxylic acids or ester-forming derivatives thereof can be used. In addition, these other dicarboxylic acid components may be used alone or in combination of two or more.

  When other dicarboxylic acid components are included in the dicarboxylic acid component (B), the ratio of the other dicarboxylic acid components increases the glass transition temperature (Tg) and maintains heat resistance while maintaining processability and polymerization efficiency of the polyester resin. From the viewpoint of further improving the dispersion, maintaining the reverse wavelength dispersion, and further improving the birefringence, it is preferably 30 mol% or less, more preferably 0.1 to 25 mol%, based on the entire dicarboxylic acid component (B). Preferably, 0.2 to 20 mol% is more preferable, 0.3 to 15 mol% is particularly preferable, 0.4 to 10 mol% or less is further preferable, and 0.5 to 5 mol% is most preferable.

  The dicarboxylic acid component (B) may be used in combination with other acid components (carboxylic acid components) as long as the effects of the present invention are not impaired. Examples of such an acid component include an unsaturated carboxylic acid component, a polycarboxylic acid component having 3 or more carboxyl groups, and the like.

Examples of the unsaturated carboxylic acid include unsaturated aliphatic dicarboxylic acids (C _2-10 alkene-dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid), and unsaturated alicyclic dicarboxylic acids (particularly cycloalkene dicarboxylic acids). (C _5-10 cycloalkene-dicarboxylic acid such as cyclohexene dicarboxylic acid), di- or tricycloalkene dicarboxylic acid (such as norbornene dicarboxylic acid)) and the like. Moreover, these ester-forming derivatives can also be used suitably.

  Examples of the polycarboxylic acid having 3 or more carboxyl groups include aromatic polycarboxylic acids such as trimellitic acid and pyromellitic acid.

  These other acid components may be used alone or in combination of two or more.

  In addition, when using another acid component, 10 mol% or less is preferable with respect to the total amount of a dicarboxylic acid component (B) and another acid component, and the ratio of another acid component is 0.1-8 mol%. More preferably, 0.2-5 mol% is further more preferable.

(3) Characteristics of polyester resin and production method The polyester resin of the present invention comprises the diol component (A) and the dicarboxylic acid component (B) as polymerization components (or the diol component (A) and the dicarboxylic acid component (B). ) Is a polyester resin polymerized) and is excellent in various properties (particularly optical properties, thermal properties, processability, etc.). Specifically, the polyester resin of the present invention has a combination of a specific diol component (derived structural unit) and a specific dicarboxylic acid component (derived structural unit), thereby having high heat resistance and a sheet. Or, when formed into a film, it is excellent in the balance between birefringence and reverse wavelength dispersion (in particular, high in-plane retardation and low in-plane retardation wavelength dispersion). In addition, the polyester resin of the present invention can have high processability and can also have excellent polymerization efficiency.

  In such a polyester resin of the present invention, the glass transition temperature (Tg) is further increased to further improve the heat resistance while maintaining the processability and the polymerization efficiency of the polyester resin, while maintaining the reverse wavelength dispersibility. From the viewpoint of further improving refraction, the diol component (A) is 20 to 80 mol% (particularly 30 to 70 mol%, more preferably 40 to 60 mol%), and the dicarboxylic acid component (B) is 20 to 80 mol% ( In particular, it is preferable to contain 30 to 70 mol%, further 40 to 60 mol%).

  The glass transition temperature (Tg) of the polyester resin of this invention is 120-200 degreeC, for example, Preferably it is 121-180 degreeC, More preferably, it is 122-160 degreeC, More preferably, it is 123-150 degreeC, Most preferably, it is 124-140. It can be set to 125 ° C, more preferably 125 to 135 ° C. Thereby, the heat resistance and workability of the polyester resin of the present invention can be further improved. The glass transition temperature is measured with a differential scanning calorimeter.

  The weight average molecular weight of the polyester resin of the present invention is, for example, about 5,000 to 500,000, preferably 7,000 to 300,000, more preferably 8,000 to 200,000, further preferably 10,000 to 150,000, particularly preferably 12,000 to 100,000, and most preferably 13,000. 70,000. In addition, a weight average molecular weight shall be measured with a GPC measuring apparatus.

  The polyester resin of the present invention can be produced by reacting (polymerizing or condensing) the diol corresponding to the diol component (A) and the dicarboxylic acid corresponding to the dicarboxylic acid component (B) or an ester-forming derivative thereof. . The polymerization method (manufacturing method) can be appropriately selected according to the type of diol, dicarboxylic acid and the like to be used, and is a conventional method such as a melt polymerization method (a method of polymerizing a diol and a dicarboxylic acid under melt mixing). Examples thereof include a solution polymerization method and an interfacial polymerization method. Of these, the melt polymerization method is preferred from the viewpoint of cost.

  Also, a diol corresponding to the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) in the diol component (A) in the reaction, a diol corresponding to the aliphatic diol component (A2), etc., a dicarboxylic acid component Use of dicarboxylic acid corresponding to dicarboxylic acid component (B1) having a fluorene skeleton in (B) or an ester-forming derivative thereof, dicarboxylic acid corresponding to non-fluorene aromatic dicarboxylic acid component (B2) or an ester-forming derivative thereof The amount (use ratio) can be selected from a range similar to the range described in the item of each component, but if necessary, at least one component may be used in excess. For example, in the diol component (A), the diol corresponding to the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) exceeds the desired ratio of the diol corresponding to the aliphatic diol component (A2). May be used for In addition, the reaction can be appropriately performed in the presence or absence of a solvent depending on the polymerization method.

The reaction can usually be performed in the presence of a catalyst. The catalyst is not particularly limited, and various catalysts used for producing a polyester resin, such as a metal catalyst, can be used. Examples of the metal catalyst include alkali metals such as sodium; alkaline earth metals such as magnesium, calcium and barium; transition metals such as manganese, zinc, cadmium, lead and cobalt; periodic table group 13 metals such as aluminum; germanium A metal compound containing a periodic table group 14 metal such as antimony; a periodic table group 15 metal such as antimony can be suitably used. Examples of the metal compound include the above-described metal alkoxides; organic acid salts such as acetates and propionates; inorganic acid salts such as borates and carbonates; metal oxides and the like. These catalysts may be used alone or in combination of two or more. The amount of these catalysts used is, for example, 1.0 × 10 ^{−6 to} 1.0 × 10 ⁻² mol, preferably 1.0 with respect to 1 mol of the total amount of dicarboxylic acid corresponding to the dicarboxylic acid component (B). It may be about x10 ^{−3 to} 4.0 × 10 ⁻³ mol.

  In the present invention, as described above, since the aliphatic diol component (A2) can also be a reaction solvent, the reaction solvent may not be used, but a reaction solvent may be used. Reaction solvents include aliphatic hydrocarbons (hexane, cyclohexane, heptane, etc.), aliphatic halogenated hydrocarbons (dichloromethane, chloroform, carbon tetrachloride, dichloroethane, etc.), aromatic hydrocarbons (benzene, toluene, xylene) , Chlorobenzene, etc.), ethers (diethyl ether, dibutyl ether, dimethoxyethane (DME), cyclopentyl methyl ether (CPME), tert-butyl methyl ether, tetrahydrofuran, dioxane, etc.), esters (ethyl acetate, ethyl propionate, etc.) Acid amides (dimethylformamide (DMF), dimethylacetamide (DMA), N-methylpyrrolidone (1-methyl-2-pyrrolidinone) (NMP), nitriles (acetonitrile, propionitrile, etc.), dimethyls Sulfoxide (DMSO) and the like. They may be used in combination of at least one kind alone or two kinds.

  Moreover, you may perform reaction in presence of additives, such as stabilizers (an antioxidant, a heat stabilizer, etc.) as needed. At this time, as the type of additives such as stabilizers (antioxidants, heat stabilizers, etc.), additives usually used when synthesizing polyester resins can be used, and stabilizers (antioxidants) The amount of an additive such as a heat stabilizer or the like may be a normal amount used when a polyester resin is synthesized.

The reaction can usually be performed in an inert gas (nitrogen, helium, argon, etc.) atmosphere. The reaction can also be performed under reduced pressure (for example, about 1 × 10 ² to 1 × 10 ⁴ Pa). The reaction temperature can be appropriately selected according to the polymerization method. For example, the reaction temperature in the melt polymerization method can be set to 150 to 300 ° C, preferably 180 to 290 ° C, and more preferably about 200 to 280 ° C. The reaction time is not particularly limited as long as the polyester resin of the present invention can be obtained. In addition, the polyester resin of the present invention can have a relatively low viscosity because a specific dicarboxylic acid component (B) including a dicarboxylic acid component (B1) having a fluorene skeleton is used as a polymerization component. Easy to manufacture. In addition, melt polymerization may be performed under reduced pressure in order to remove by-product water and the like, but even under such reduced pressure, the polyester resin reflecting the preparation is efficiently reflected without distilling. Can be obtained.

(4) Molded body (retardation film)
As described above, the polyester resin of the present invention has high heat resistance and a balance between birefringence and reverse wavelength dispersion when formed into a sheet or film (in particular, high in-plane retardation and low in-plane level). Excellent in retardation wavelength dispersion. The polyester resin of the present invention can also have high processability. For this reason, the polyester resin of the present invention is particularly useful as a retardation film. The shape of the retardation film of the present invention is not particularly limited as long as it is a sheet or film.

  Such a retardation film of the present invention is not particularly limited as long as it is obtained using the polyester resin of the present invention, and may be formed only from the polyester resin of the present invention, or the polyester resin of the present invention. It may be formed from the resin composition containing. In addition to the polyester resin of the present invention, such a resin composition includes various additives (for example, fillers or reinforcing agents; coloring agents such as dyes and pigments; conductive agents; flame retardants; plasticizers; lubricants; antioxidants; Stabilizers such as UV absorbers and heat stabilizers; mold release agents; antistatic agents; dispersants; flow regulators; leveling agents; antifoaming agents; surface modifiers; silicone oil, silicone rubber, various plastic powders, various types 1 type or 2 types or more, such as low stress agents, such as engineering plastic powder; heat resistance improving agents, such as a sulfur compound and polysilane; carbon materials, etc.).

  The retardation film of the present invention is obtained by using the polyester resin or a resin organism containing the polyester resin in the form of a sheet or film using a conventional film forming method, casting method (solvent casting method), melt film forming method, calendar method, and the like. It can be manufactured by forming a film (or molding) on an object. Of these, the melt film-forming method is preferable from the viewpoints of environmental load suppression and manufacturing facility corrosion suppression.

  The thickness of the retardation film of the present invention thus obtained can be 1-1000 μm, preferably 5-800 μm, more preferably 10-600 μm, and even more preferably 100-400 μm.

  The retardation film of the present invention may be a stretched film. Since the polyester resin of the present invention has high processability, a stretched film can be easily produced. The retardation film of the present invention has birefringence (particularly in-plane retardation) and reverse wavelength dispersion (particularly in-plane retardation wavelength). Since both are excellent in (dispersibility), even if the retardation film of the present invention is a stretched film, birefringence and reverse wavelength dispersibility can be maintained at a high level. In particular, by using the retardation film of the present invention as a stretched film, the reverse wavelength dispersion (particularly in-plane retardation wavelength dispersion) is maintained at a high level, and the birefringence (particularly in-plane retardation) is superior. A retardation film can be obtained. Such a stretched film may be either a uniaxially stretched film or a biaxially stretched film.

  In the case where the retardation film of the present invention is used as a stretched film, the stretching temperature is preferably set appropriately so as to obtain desired characteristics, and varies depending on the glass transition temperature of the polyester resin of the present invention. Temperature-Glass transition temperature of polyester resin + 20 ° C, preferably Glass transition temperature of polyester resin + 3 ° C-Glass transition temperature of polyester resin + 10 ° C, more preferably Glass transition temperature of polyester resin + 4 ° C-Glass transition temperature of polyester resin + 8 The glass transition temperature of the polyester resin + 5 ° C to the glass transition temperature of the polyester resin + 7 ° C can be more preferable. Thereby, the birefringence and reverse wavelength dispersion of the retardation film of the present invention can be made closer to ideal values.

  In the case where the retardation film of the present invention is used as a stretched film, the stretching ratio is preferably set as appropriate so as to obtain desired characteristics. Specifically, the stretching ratio is 1 in each direction in uniaxial stretching or biaxial stretching. 0.1 to 10 times, preferably 1.2 to 8 times, more preferably 1.5 to 6 times, still more preferably 1.7 to 5 times, and particularly preferably 2 to 4 times. In addition, when employ | adopting biaxial stretching, it may be equal stretching (for example, 1.5 to 5 times stretching in both the longitudinal and transverse directions), and uneven stretching (for example, 1.1 to 4 times in the longitudinal direction and 2 in the lateral direction). -6 times stretching). In the case of uniaxial stretching, longitudinal stretching (for example, 2.5 to 8 times stretching in the longitudinal direction) or lateral stretching (for example, 1.2 to 5 times stretching in the transverse direction) may be used. Thereby, the birefringence and reverse wavelength dispersion of the retardation film of the present invention can be made closer to ideal values.

  When the retardation film of the present invention is a stretched film, the thickness may be 1 to 500 μm, preferably 2 to 400 μm, more preferably 3 to 300 μm, and still more preferably 30 to 200 μm.

  Such a stretched film can be obtained by subjecting the retardation film (or unstretched retardation film) formed by the melt film-forming method or the like as described above to a stretching treatment. The stretching method is not particularly limited. In the case of uniaxial stretching, either a wet stretching method or a dry stretching method may be used. In the case of biaxial stretching, a tenter method (also called a flat method) is a tube method. However, a tenter method having excellent stretch thickness uniformity is preferred.

  The retardation film of the present invention thus obtained has an in-plane retardation (R550 nm) when measured at a wavelength of 550 nm as one of birefringence indices, and is preferably 50 to 1000 nm in terms of thickness 100 μm, preferably May be 60 to 800 nm, more preferably 80 to 600 nm, still more preferably 100 to 500 nm, and particularly preferably 120 to 400 nm. This in-plane retardation is measured with a retardation measuring device.

  The retardation film of the present invention thus obtained is an in-plane retardation when measured at a wavelength of 550 nm and an in-plane retardation when measured at a wavelength of 550 nm, as one of the indicators of reverse wavelength dispersion. (R450nm / R550nm) is 0.65 to 1.000, preferably 0.70 to 0.995, more preferably 0.75 to 0.990, still more preferably 0.80 to 0.980, Particularly preferably, it may be 0.82 to 0.975. This in-plane retardation dispersion is measured with a retardation measuring device.

(5) Circularly polarizing plate, elliptically polarizing plate, and image display device The retardation film of the present invention may be bonded to a polarizing plate via an adhesive layer, an adhesive layer, etc. as necessary to form a circularly polarizing plate or an elliptically polarizing plate. It is also possible to improve the wet heat durability or improve the solvent resistance by coating some material on the retardation film. In this case, unlike the conventional retardation film, it is not necessary to use the retardation film of the present invention as a laminated film, and while using only one sheet, it converts linearly polarized light into circularly polarized light for broadband light. Or circularly polarized light can be converted into linearly polarized light. At this time, the adhesive layer, the adhesive layer, and the like can be formed by a conventionally known method using a conventionally used material.

  The retardation film of the present invention can also be used for image display devices such as organic EL display devices. This image display device is not particularly limited except that it comprises the retardation film of the present invention (particularly the above-mentioned circularly polarizing plate or elliptically polarizing plate), and requires members such as a power source, a backlight unit, and an operation unit. Depending on the situation. In the image display device of the present invention, when the retardation film of the present invention is used as an element for converting circularly polarized light into linearly polarized light, good linearly polarized light can be obtained in a wide band, and an organic EL device having excellent image quality, etc. An image display device can be obtained.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

  In addition, the measurement and evaluation of the characteristic of a polyester resin or retardation film were performed with the following method.

[Glass-transition temperature]
Using a differential scanning calorimeter (Seiko Instruments Co., Ltd., DSC 6220), the sample was placed in an aluminum pan and the glass transition temperature (Tg) was measured in the range of 30 to 220 ° C.

[Birefringence (in-plane retardation; R550 nm)]
Using a retardation measuring device RETS-100 manufactured by Otsuka Electronics Co., Ltd., birefringence (in-plane retardation: R550 nm) was measured with monochromatic light of 550 nm.

  Specifically, the polyester resin of each Example was press-molded at 160 to 240 ° C. to obtain a film having a thickness of 100 to 400 μm, and then cut into a 15 × 50 mm strip to obtain a test specimen for measurement. . Then, the test piece for measurement was measured at a temperature of glass transition temperature (Tg) + 4 ° C., glass transition temperature (Tg) + 5 ° C., glass transition temperature (Tg) + 6 ° C., or glass transition temperature (Tg) + 10 ° C. at 25 mm / min. The film was stretched 2.5 times or 3 times to obtain a retardation film (stretched film) of the present invention. The birefringence (retardation) of these films was measured using the above apparatus, and the in-plane retardation (R550 nm) was measured by converting the film thickness to 100 μm.

[Reverse wavelength dispersion (in-plane retardation wavelength dispersion; R450 nm / R550 nm)]
The in-plane retardation 450 nm was measured in the same manner as the in-plane retardation (R550 nm) except that the measurement wavelength was 450 nm. Thereafter, the inverse wavelength dispersion (in-plane retardation wavelength dispersion; R450 nm / R550 nm) was calculated from the obtained values of R550 nm and R450 nm.

Example 1
9,9-di (2-methoxy) as in Example 1 of JP-A-2005-089422, except that t-butyl acrylate was changed to methyl acrylate (37.9 g, 0.44 mol). Carbonylethyl) fluorene (9,9-di (2-carboxyethyl) fluorene or dimethyl ester of fluorene-9,9-dipropionic acid; hereinafter referred to as FDPM) was synthesized.

In a reactor, FDPM 0.10 mol, dimethyl isophthalate (hereinafter referred to as DMI) 0.90 mol, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene (manufactured by Osaka Gas Chemical Co., Ltd., the following) BPEF) 0.80 mol, ethylene glycol (hereinafter referred to as EG) 2.20 mol, manganese acetate tetrahydrate 2 × 10 ⁻⁴ mol and calcium acetate monohydrate 8 × 10 as the transesterification catalyst ^-4 mol was added and gradually heated and melted with stirring, and the temperature was raised to 230 ° C. Then, trimethyl phosphate 1.4 × 10 ^-3 mol and germanium oxide 2.0 × 10 ^-3 mol were added, and 270 ° C, 0 The ethylene glycol was removed while gradually raising the temperature and reducing the pressure until it reached 13 kPa or less. After reaching a predetermined stirring torque, the contents were taken out of the reactor to obtain polyester resin pellets. In addition, since 2 mol of EG is discharged out of the system during the polymerization, the content of the constituent unit derived from EG constituting the polyester resin is 0.2 mol.

  When the obtained pellet was analyzed by NMR, 10 mol% of the dicarboxylic acid component introduced into the polyester resin was derived from FDPM and 90 mol% was derived from DMI. Moreover, 80 mol% of the diol component introduced into the polyester resin was derived from BPEF, and 20 mol% was derived from EG.

  The obtained polyester resin had a glass transition temperature (Tg) of 129 ° C. and a weight average molecular weight of 38000. This polyester resin had an in-plane retardation (R550 nm) of 122 nm and an in-plane retardation wavelength dispersion (R450 nm / R550 nm) of 0.994 when stretched three times at a glass transition temperature (Tg) + 10 ° C. It was.

Example 2
Polyester resin pellets were obtained in the same manner as in Example 1 except that the addition amount (number of moles) of FDPM and DMI was changed to FDPM 0.15 mol and DMI 0.85 mol.

  When the obtained pellet was analyzed by NMR, 15 mol% of the dicarboxylic acid component introduced into the polyester resin was derived from FDPM and 85 mol% was derived from DMI. Moreover, 80 mol% of the diol component introduced into the polyester resin was derived from BPEF, and 20 mol% was derived from EG.

  The polyester resin obtained had a glass transition temperature (Tg) of 128 ° C. and a weight average molecular weight of 40,400. This polyester resin had an in-plane retardation (R550 nm) of 154 nm and an in-plane retardation wavelength dispersion (R450 nm / R550 nm) of 0.974 when stretched 3 times at a glass transition temperature (Tg) + 10 ° C. It was.

Example 3
Polyester resin pellets were obtained in the same manner as in Example 1 except that the addition amount (number of moles) of FDPM and DMI was changed to 0.20 mol of FDPM and 0.80 mol of DMI.

  When the obtained pellet was analyzed by NMR, 20 mol% of the dicarboxylic acid component introduced into the polyester resin was derived from FDPM, and 80 mol% was derived from DMI. Moreover, 80 mol% of the diol component introduced into the polyester resin was derived from BPEF, and 20 mol% was derived from EG.

  The obtained polyester resin had a glass transition temperature (Tg) of 125 ° C. and a weight average molecular weight of 34100. This polyester resin had an in-plane retardation (R550 nm) of 60 nm and an in-plane retardation wavelength dispersion (R450 nm / R550 nm) of 0.935 when stretched three times at a glass transition temperature (Tg) + 10 ° C. It was.

Example 4
Polyester resin pellets were obtained in the same manner as in Example 1 except that the addition amount (number of moles) of FDPM, DMI and dimethyl terephthalate (hereinafter referred to as DMT) was changed to FDPM 0.30 mol and DMT 0.70 mol. .

  When the obtained pellet was analyzed by NMR, 30 mol% of the dicarboxylic acid component introduced into the polyester resin was derived from FDPM, and 70 mol% was derived from DMT. Moreover, 80 mol% of the diol component introduced into the polyester resin was derived from BPEF, and 20 mol% was derived from EG.

  The resulting polyester resin had a glass transition temperature (Tg) of 137 ° C. and a weight average molecular weight of 38,300. This polyester resin had an in-plane retardation (R550 nm) of 94 nm and an in-plane retardation wavelength dispersion (R450 nm / R550 nm) of 0.982 when stretched three times at a glass transition temperature (Tg) + 10 ° C. It was.

Example 5
Polyester resin pellets were obtained in the same manner as in Example 1 except that the addition amounts (number of moles) of FDPM, DMI and DMT were changed to FDPM 0.35 mol and DMT 0.65 mol.

  When the obtained pellet was analyzed by NMR, 35 mol% of the dicarboxylic acid component introduced into the polyester resin was derived from FDPM, and 65 mol% was derived from DMT. Moreover, 80 mol% of the diol component introduced into the polyester resin was derived from BPEF, and 20 mol% was derived from EG.

  The obtained polyester resin had a glass transition temperature (Tg) of 136 ° C. and a weight average molecular weight of 39800. About this polyester resin, the in-plane phase difference (R550nm) at the time of extending | stretching at the temperature of glass transition temperature (Tg) +4 degreeC was 64 nm by 2.5 time extending | stretching. With respect to this polyester resin, the in-plane retardation (R550 nm) when stretched at a temperature of glass transition temperature (Tg) + 5 ° C. was 69 nm by 2.5 times stretching and 74 nm by 3 times stretching. With respect to this polyester resin, the in-plane retardation (R550 nm) when stretched at a temperature of glass transition temperature (Tg) + 6 ° C. was 74 nm by 2.5 times stretching and 86 nm by 3 times stretching. About this polyester resin, the in-plane phase difference (R550nm) at the time of extending | stretching at the temperature of glass transition temperature (Tg) +10 degreeC was 72 nm. With respect to this polyester resin, the in-plane retardation wavelength dispersibility (R450 nm / R550 nm) when stretched at a temperature of glass transition temperature (Tg) + 4 ° C. was 0.776 when stretched 2.5 times. With respect to this polyester resin, the in-plane retardation wavelength dispersion (R450 nm / R550 nm) when stretched at a glass transition temperature (Tg) + 5 ° C. is 0.671 by 2.5 times stretching and 0.582 by 3 times stretching. Met. With respect to this polyester resin, the in-plane retardation wavelength dispersibility (R450 nm / R550 nm) when stretched at a glass transition temperature (Tg) + 6 ° C. is 0.832 by 2.5 times stretching and 0.645 by 3 times stretching. Met. This polyester resin had an in-plane retardation wavelength dispersibility (R450 nm / R550 nm) of 0.947 when stretched three times at a temperature of glass transition temperature (Tg) + 10 ° C.

  The results are shown in Tables 1 and 2.

Claims (15)

A polyester resin for a retardation film having a diol component (A) and a dicarboxylic acid component (B) as polymerization components,
The diol component (A) includes a 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1), and
The dicarboxylic acid component (B) is a polyester resin for a retardation film containing a dicarboxylic acid component (B1) having a fluorene skeleton. The said diol component (A) is a polyester resin for retardation films of Claim 1 which contains an aliphatic diol component (A2) further. The polyester for retardation films according to claim 1 or 2, wherein the content of the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) in the diol component (A) is 40 mol% or more. resin. The total amount of the 9,9-bis (hydroxy (poly) alkoxyaryl) fluorene component (A1) and the aliphatic diol component (A2) in the diol component (A) is 50 mol% based on the entire diol component (A). The polyester resin for retardation films according to claim 2 or 3, which is as described above. The polyester resin for retardation films according to any one of claims 1 to 4, wherein the dicarboxylic acid component (B1) having a fluorene skeleton is a dicarboxylic acid ester-forming derivative component having a fluorene skeleton. The said dicarboxylic acid component (B) is a polyester resin for retardation films in any one of Claims 1-5 containing a non-fluorene aromatic dicarboxylic acid component (B2) further. The polyester resin for retardation films according to claim 6, wherein the non-fluorene aromatic dicarboxylic acid component (B2) is a monocyclic aromatic dicarboxylic acid component. The polyester resin for retardation films according to any one of claims 1 to 7, wherein the content of the dicarboxylic acid component (B1) having a fluorene skeleton in the dicarboxylic acid component (B) is 5 mol% or more. The polyester resin for retardation films according to claim 1, wherein the glass transition temperature is 120 to 200 ° C. The retardation film using the polyester resin for retardation films in any one of Claims 1-9. The method for producing a retardation film according to claim 10, wherein a sheet or a film-like material is formed using the polyester resin for retardation film or the resin composition containing the polyester resin for retardation film. . The method for producing a retardation film according to claim 11, wherein a melt film-forming method is adopted when the sheet or the film-like material is formed. The method for producing a retardation film according to claim 11, wherein the sheet or film-like material is stretched in at least one direction. The retardation film of Claim 10, or the retardation film obtained by the manufacturing method in any one of Claims 11-13, and a circularly-polarizing plate or elliptically polarizing plate provided with a polarizing plate and / or a reflective polarizing plate. Board. An image display apparatus provided with the retardation film of Claim 10, or the retardation film obtained by the manufacturing method in any one of Claims 11-13.