JP7680910B2 - Fluorene derivatives and resins, and methods of producing and using the same - Google Patents

Description

The present invention relates to a novel diol compound having a fluorene skeleton, a resin containing this diol compound as a polymerization component, and a method for producing and using the same.

Diol compounds having a fluorene skeleton are often used as optical plastics (or optical resin materials) taking advantage of their optical properties such as high refractive index. In particular, diol compounds having a 9,9-bisarylfluorene skeleton are known to exhibit particularly excellent optical properties due to their cardo structure. For example, Patent Documents 1 to 4 disclose polyester resins and polycarbonate resins that contain diol compounds having a 9,9-bisarylfluorene skeleton as a polymerization component.

Patent Document 5 discloses that a polyester resin containing a diol compound having a specific fluorene skeleton as a polymerization component, although not a 9,9-bisarylfluorene skeleton, exhibits negative birefringence, and that this polyester resin can be used to form a multilayer optical film.

JP 2017-179323 A JP 2018-104691 A JP 2016-69643 A JP 2018-172658 A US Patent Application Publication No. 2012/0170118

In the examples of Patent Documents 1 and 2, polycarbonate resins are prepared that contain, as polymerization components, diol compounds having a 9,9-bisarylfluorene skeleton, such as 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene (BNEF), 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF), and 9,9-bis(6-hydroxy-2-naphthyl)fluorene (BNF).

In addition, in the examples of Patent Documents 3 and 4, polyester resins are prepared that contain the above-mentioned BNEF, BPEF, and 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene (BOPPEF) as polymerization components, as diol compounds having a 9,9-bisarylfluorene skeleton.

Although the resins obtained in the examples of Patent Documents 1 to 4 exhibit a high refractive index, there remains a high demand for optical resin materials with a high refractive index, and depending on the application, this may not be sufficient.

When attempting to form a resin from a monomer having many benzene ring skeletons (or aromatic ring skeletons) in order to achieve an even higher refractive index, the glass transition temperature Tg rises excessively due to the rigidity of the benzene ring skeleton, resulting in a decrease in fluidity (melt fluidity), making injection molding and the like difficult, and a decrease in moldability (handling ability or productivity). In other words, there is a trade-off between a high refractive index and high moldability, and it is not easy to achieve a higher refractive index.
Furthermore, since there is a trade-off between a high refractive index and a low birefringence, a resin having many benzene ring structures introduced therein may easily have an increased birefringence.

In addition, Example 1c of Patent Document 5 describes the preparation of 9,9-bis(3-hydroxypropyl)fluorene by reacting 9,9-bis[2-(ethoxycarbonyl)ethyl]fluorene with lithium aluminum hydride, and further describes the preparation of polyester resins containing this diol compound as a polymerization component in Examples 9, 12, 16, and 18.

However, the diol components used in these examples are not diol compounds with a 9,9-bisarylfluorene skeleton, so the refractive index of the resulting polyester resin is not very high.

The object of the present invention is therefore to provide a novel diol compound capable of forming a resin that exhibits a high refractive index and has excellent moldability (handling ability or productivity), a resin that contains this diol compound as a polymerization component, and a method for producing and using the same.

As a result of intensive research conducted by the inventors to achieve the above object, they discovered that a diol compound having a specific chemical structure in which aryl groups are bonded to the 1-8 positions of a fluorene skeleton and an alkylene group is bonded to the 9,9 positions can unexpectedly form a resin that exhibits a remarkably high refractive index without impairing moldability, despite not having a 9,9-bisarylfluorene skeleton, and thus completed the present invention.

That is, the diol compound of the present invention is represented by the following formula (1).

[In the formula, Y ^1a and Y ^1b each independently represent a monovalent group represented by the following formula (Y1), k1a and k1b each independently represent an integer of 0 to 4, and at least one of k1a and k1b is 1 or more,
R ^2a and R ^2b each independently represent a substituent; m2a and m2b each independently represent an integer of 0 to 4;
k1a + m2a and k1b + m2b are each independently 4 or less;
^Y2a and ^Y2b each independently represent a monovalent group represented by the following formula (Y2).

(wherein ^Z1 represents an arene ring;
^R1 represents a substituent, and m1 represents an integer of 0 or 1 or more.

(In the formula, A ¹ and A ² each independently represent a linear or branched alkylene group, and n 2 represents 0 or an integer of 1 or more).

In the formula (1), Z ¹ may be a C _6-12 arene ring, and k1a and k2b may be integers of about 1 to 2,
A ¹ may be a linear or branched C _1-6 alkylene group;
^A2 may be a linear or branched _C2-4 alkylene group, and n2 may be 0 or an integer of about 1 to 10.

In addition, in the formula (1), ^Z1 may be a benzene ring or a naphthalene ring, k1a and k2b may be 1,
A ¹ may be a linear or branched C _1-4 alkylene group;
n2 may be 0.

The present invention includes a method for producing the diol compound, which includes a reduction step of reducing a compound represented by the following formula (I):

[In the formula, ^Y3a and ^Y3b each independently represent a monovalent group represented by the following formula (Y3),
Y ^1a and Y ^1b , k1a and k1b, R ^2a and R ^2b , and m2a and m2b are the same as those in formula (1).

(In the formula, ^A3 represents a linear or branched alkylene group,
^R3 represents a hydrogen atom or an alkyl group.

The present invention also includes a resin containing a structural unit represented by the following formula (1P):

[In the formula, Y ^2c and Y ^2d each independently represent a divalent group represented by the following formula (Y2c):
Y ^1a and Y ^1b , k1a and k1b , R ^2a and R ^2b , and m2a and m2b are the same as those in formula (1).

(In the formula, A ¹ , A ² and n2 are the same as those in the above formula (1), and A ¹ is bonded to the 9-position of the fluorene ring).

The resin may be a polyester resin containing the first diol unit (A1) represented by the formula (1P) as the diol unit (A). The proportion of the first diol unit (A1) represented by the formula (1P) may be about 5 to 100 mol % based on the total diol unit (A).

The resin may be a polycarbonate resin. In the polycarbonate resin, the diol unit (A) may further include a second diol unit (A2) represented by the following formula (2):

(In the formula, Z ^2a and Z ^2b each independently represent an arene ring,
^R4 represents a substituent; m4 represents an integer of 0 to 8;
^R5a and ^R5b each independently represent a substituent; m5a and m5b each independently represent an integer of 0 or 1 or more;
^A4a and ^A4b each independently represent a linear or branched alkylene group, and n4a and n4b each independently represent an integer of 0 or 1 or more.

In the formula (2), Z ^2a and Z ^2b may be a C _6-10 arene ring, R ^5a and R ^5b may be a hydrocarbon group, and m5a and m5b may be an integer of about 0 to 2,
A ^4a and A ^4b may be a linear or branched C _2-6 alkylene group, and n4a and n4b may be an integer of about 0 to 3.

In the polycarbonate resin, the ratio of the first diol unit (A1) to the second diol unit (A2) may be the former/latter (molar ratio) = approximately 20/80 to 80/20.

The resin may be a polyester carbonate resin. In the polyester carbonate resin, the diol unit (A) may further include the second diol unit (A2). The polyester carbonate resin may further include a first dicarboxylic acid unit (B1) represented by the following formula (4) as the dicarboxylic acid unit (B).

(In the formula, ^R6 represents a substituent, m6 represents an integer of 0 to 8,
A ^6a and A ^6b each independently represent a linear or branched alkylene group.

In the polyester carbonate resin, the ratio of the first diol unit (A1) to the second diol unit (A2) may be the former/the latter (molar ratio) of about 10/90 to 50/50,
The ratio of the dicarboxylic acid unit (B) may be about 0.5 to 0.85 mol per 1 mol of the diol unit (A),
The proportion of the first dicarboxylic acid unit (B1) may be about 50 to 100 mol % based on the total of the dicarboxylic acid units (B).

The resin may be a polyester resin. In the polyester resin, the diol unit (A) may further include a third diol unit (A3) represented by the following formula (3):

(In the formula, ^A5 represents a linear or branched alkylene group, and n5 represents an integer of 1 or more).

The polyester resin may further contain the first dicarboxylic acid unit (B1) as the dicarboxylic acid unit (B). The dicarboxylic acid unit (B) may contain a second dicarboxylic acid unit (B2) represented by the following formula (5).

(Wherein, ^Z3 represents an arene ring;
^R7 represents a substituent, and m7 represents an integer of 0 or 1 or more.

In the polyester resin, the ratio of the first diol unit (A1) to the third diol unit (A3) may be the former/the latter (molar ratio)=about 70/30 to 95/5,
The ratio of the first dicarboxylic acid unit (B1) may be about 0.3 to 1.5 moles per mole of the first diol unit (A1),
The ratio of the first dicarboxylic acid unit (B1) to the second dicarboxylic acid unit (B2) may be the former/latter (molar ratio) of about 50/50 to 90/10.

The present invention also includes a molded article containing the resin. The molded article may be an optical member such as an optical film or an optical lens.

In addition, the present invention may solve the following problems as a secondary objective:

That is, another object of the present invention is to provide a diol compound capable of forming a resin having a good balance of a high refractive index, high moldability, and low birefringence, a resin containing this diol compound as a polymerization component, and a method for producing the same and uses thereof.

A further object of the present invention is to provide a diol compound capable of forming a resin that exhibits a low Abbe number while satisfying a good balance of a high refractive index, high moldability, and low birefringence, and a resin that contains this diol compound as a polymerization component, as well as a method for producing the same and uses thereof.

In this specification and claims, "diol unit" means a constituent unit derived from a diol component, i.e., a unit (or a divalent group) obtained by removing hydrogen atoms from two hydroxyl groups of the corresponding diol, and "diol component" (including compounds exemplified as diol components) may be used synonymously with the corresponding "diol unit."

The term "dicarboxylic acid unit" refers to a structural unit derived from a dicarboxylic acid component, that is, a unit (or a divalent group) obtained by removing OH (hydroxyl group) from two carboxyl groups of the corresponding dicarboxylic acid. The term "dicarboxylic acid component" refers to a dicarboxylic acid as well as a derivative that can be used as a polymerization component, such as an ester-forming derivative, such as a dicarboxylic acid ester, a dicarboxylic acid halide, or a dicarboxylic acid anhydride. Examples of the dicarboxylic acid ester include dicarboxylic acid component alkyl esters, particularly lower alkyl esters, such as C _1-4 alkyl esters, such as methyl esters, ethyl esters, and t-butyl esters. Examples of the dicarboxylic acid halide include dicarboxylic acid chlorides and dicarboxylic acid bromides. The ester-forming derivative may be a monoester (half ester) or a diester. The term "dicarboxylic acid component" (including compounds exemplified as dicarboxylic acid components) may be used synonymously with the corresponding "dicarboxylic acid unit".

In this specification and claims, the number of carbon atoms in a substituent may be designated as _C1 , _C6 , _C10 , etc. For example, an alkyl group having one carbon atom is designated as a " _C1 alkyl" and an aryl group having 6 to 10 carbon atoms is designated as a " _C6-10 aryl."

In addition, in this specification and claims, unless otherwise specified, the terms "low birefringence" and "low birefringence" mean that the absolute value of birefringence is low (i.e., close to 0).

The diol compound having the specific chemical structure of the present invention can form a resin that exhibits a high refractive index and has excellent moldability (handleability or productivity) despite not having a 9,9-bisarylfluorene skeleton. It can also form a resin that not only has a high refractive index and high moldability, but also has low birefringence in a well-balanced manner. It can also form a resin that has a high refractive index, high moldability, low birefringence, and a low Abbe number in a well-balanced manner.

[Diol compound represented by formula (1)]
The novel diol compound (also referred to as the first diol component) of the present invention is represented by the formula (1). In the formula (1), examples of the arene ring (aromatic hydrocarbon ring) represented by ^Z1 in the formula (Y1) representing the monovalent groups ^Y1a and ^Y1b include a monocyclic arene ring such as a benzene ring, a polycyclic arene ring, etc. Examples of the polycyclic arene ring include a condensed polycyclic arene ring (condensed polycyclic aromatic hydrocarbon ring), a ring-assembled arene ring (ring-assembled aromatic hydrocarbon ring), etc.

Examples of the fused polycyclic arene ring include fused bicyclic arene rings, fused tricyclic arene rings, and other fused bi- to tetracyclic arene rings. Examples of the fused bicyclic arene ring include fused bicyclic C _10-16 arene rings, such as a naphthalene ring and an indene ring. Examples of the fused tricyclic arene ring include fused tricyclic C _14-20 arene rings, such as an anthracene ring and a phenanthrene ring. A preferred fused polycyclic arene ring is a fused polycyclic C _10-14 arene ring, such as a naphthalene ring.

Examples of the ring assembly arene ring include biarene rings such as biphenyl ring, phenylnaphthalene ring, binaphthyl ring, etc.; terarene rings such as terphenyl ring, etc. A preferred ring assembly arene ring is a C _12-18 biarene ring such as a biphenyl ring.

In this specification and claims, the term "ring assembly arene ring" refers to two or more ring systems (arene ring systems) directly connected by single bonds or double bonds, and the number of bonds directly connecting the rings is one less than the number of ring systems. For example, as described above, phenylnaphthalene rings and binaphthyl rings are classified as ring assembly arene rings even if they have a fused polycyclic arene ring skeleton, and are clearly distinguished from "fused polycyclic arene rings" such as naphthalene rings (non-ring assembly arene rings).

Preferred ring Z ¹ includes a C _6-14 arene ring, more preferably a C _6-12 arene ring such as a benzene ring, a naphthalene ring or a biphenyl ring, still more preferably a C _6-10 arene ring such as a benzene ring or a naphthalene ring, particularly a naphthalene ring. When Z ¹ is a condensed polycyclic arene ring such as a naphthalene ring, the refractive index can be effectively improved and it is easy to adjust the heat resistance to an appropriate level, which is preferable.

Furthermore, the ring Z ¹ in the monovalent groups Y ^1a and Y ^1b may be substituted at any of the 1-4 and 5-8 positions of the fluorene skeleton, and examples of the position include the 2-, 3- and/or 7-positions. When the substitution numbers k1a and k1b of Y ^1a and Y ^1b are 1, preferred substitution positions (or bonding positions) are symmetrical positions on the paper in the above formula (1), such as the 1,8-positions, 2,7-positions, 3,6-positions and 4,5-positions, and the 2,7-positions are particularly preferred.

The bonding position on ring ^Z1 to the fluorene skeleton may be any position. When ring ^Z1 is a naphthalene ring, it may be either the 1st or 2nd position of the naphthalene ring, but is preferably the 2nd position of the naphthalene ring.

Examples of the substituent represented by ^R1 (non-reactive substituent or non-polymerizable substituent) include a halogen atom, a hydrocarbon group (or group [-R ^h ]), a group [-OR ^h ] (wherein R ^h represents the above-mentioned hydrocarbon group), a group [-SR ^h ] (wherein R ^h represents the above-mentioned hydrocarbon group), an acyl group, a nitro group, a cyano group, and a mono- or di-substituted amino group.

Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

Examples of the hydrocarbon group represented by ^Rh include an alkyl group, a cycloalkyl group, an aryl group, and an aralkyl group.

Examples of the alkyl group include linear or branched _C1-10 alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, s-butyl, and t-butyl groups, and are preferably linear or branched _C1-6 alkyl groups, and more preferably linear or branched _C1-4 alkyl groups.

Examples of the cycloalkyl group include a C _5-10 cycloalkyl group such as a cyclopentyl group and a cyclohexyl group.

Examples of the aryl group include C _6-12 aryl groups such as a phenyl group, an alkylphenyl group, a biphenylyl group, a naphthyl group, etc. Examples of the alkylphenyl group include mono- to tri-C _1-4 alkyl-phenyl groups such as a methylphenyl group (or a tolyl group) and a dimethylphenyl group (or a xylyl group).

Examples of the aralkyl group include a C _6-10 aryl-C _1-4 alkyl group such as a benzyl group or a phenethyl group.

Examples of the group [-OR ^h ] include an alkoxy group, a cycloalkyloxy group, an aryloxy group, and an aralkyloxy group, and specific examples of the group include those corresponding to the examples of the hydrocarbon group R ^h . Examples of the alkoxy group include linear or branched C _1-10 alkoxy groups such as a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, an isobutoxy group, and a t-butoxy group. Examples of the cycloalkyloxy group include a C _5-10 cycloalkyloxy group such as a cyclohexyloxy group. Examples of the aryloxy group include a C _6-10 aryloxy group such as a phenoxy group. Examples of the aralkyloxy group include a C _6-10 aryl-C _1-4 alkyloxy group such as a benzyloxy group.

Examples of the group [-SR ^h ] include alkylthio groups, cycloalkylthio groups, arylthio groups, and aralkylthio groups, and specific examples include groups corresponding to the examples of the hydrocarbon group R ^h . Examples of the alkylthio group include C _1-10 alkylthio groups such as methylthio groups, ethylthio groups, propylthio groups, n-butylthio groups, and t-butylthio groups. Examples of the cycloalkylthio group include C 5-10 cycloalkylthio groups such as cyclohexylthio groups. Examples of the arylthio group include _{C 6-10} arylthio groups such as thiophenoxy groups. Examples of the aralkylthio group include C _6-10 aryl-C _1-4 alkylthio groups such as benzylthio groups.

The acyl group includes a C _1-6 alkyl-carbonyl group such as an acetyl group.

Examples of the mono- or di-substituted amino group include a dialkylamino group, a bis(alkylcarbonyl)amino group, etc. Examples of the dialkylamino group include a di-C _1-4 alkylamino group such as a dimethylamino group. Examples of the bis(alkylcarbonyl)amino group include a bis(C _1-4 alkyl-carbonyl)amino group such as a diacetylamino group.

Representative examples of the group R ¹ include a hydrocarbon group, an alkoxy group, an acyl group, a nitro group, a cyano group, and a substituted amino group. When m1 is 1 or more, preferred examples of the group R ¹ include an alkyl group and an alkoxy group, specifically, a linear or branched C _1-6 alkyl group such as a methyl group, and a linear or branched C _1-4 alkoxy group such as a methoxy group, among which an alkyl group, particularly a C _1-4 alkyl group such as a methyl group, is preferred. When the group R ¹ is an aryl group, the group R ¹ may form the ring assembly arene ring together with the ring Z ¹ .

The number of substitutions m1 may be selected depending on the type of ring Z ¹ , and may be selected from integers of about 0 to 7, with preferred ranges being integers of 0 to 4 and 0 to 2, stepwise as follows, more preferably 0 or 1, particularly 0. When the number of substitutions m1 is 2 or more, the types of the two or more groups R ¹ substituting on ring Z ¹ may be the same or different from each other. The substitution position of group R ¹ is not particularly limited, and may be selected depending on the type of ring Z ¹ .

Representative monovalent groups Y ^1a and Y ^1b represented by formula (Y1) include a phenyl group, a naphthyl group such as a 1-naphthyl group or a 2-naphthyl group, and a biphenylyl group, of which a phenyl group and a naphthyl group are preferred, a naphthyl group is more preferred, and a 2-naphthyl group is particularly preferred.

The substitution numbers k1a and k1b of the monovalent groups Y ^1a and Y ^1b are, for example, integers of about 0 to 3, preferably 0 to 2, more preferably 1 or 2, and particularly preferably 1. k1a and k1b may be different from each other, but are preferably the same. At least one of k1a and k1b is an integer of 1 or more, preferably both are integers of 1 or more, and more preferably both are 1.

In addition, when k1a and k1b are each 1 or more, the types of groups ^Y1a and ^Y1b substituted on different benzene rings among the two benzene rings forming the fluorene skeleton may be different from each other, and are preferably the same. In addition, when k1a and k1b are 2 or more, the types of two or more groups ^Y1a and ^Y1b substituted on the same benzene ring among the two benzene rings may be the same or different from each other.

The substituents (non-reactive or non-polymerizable substituents) represented by R ^2a and R ^2b may be any substituent other than the groups Y ^1a and Y ^1b , and representative groups include hydrocarbon groups such as alkyl groups (excluding aryl groups), halogen atoms such as fluorine atoms, chlorine atoms and bromine atoms, and cyano groups. Examples of the alkyl groups include linear or branched C _1-6 alkyl groups such as methyl groups, ethyl groups and t-butyl groups. When the number of substitutions m2a and m2b is 1 or more, preferred R ^2a and R ^2b are C _1-4 alkyl groups such as methyl groups.

The substitution numbers m2a and m2b of R ^2a and R ^2b are, for example, integers of about 0 to 3, preferably integers of 0 to 2, more preferably 0 or 1, and particularly 0. m2a and m2b may be different from each other, but are preferably the same. When m2a and m2b are each 1 or more, the types of R ^2a and R ^2b substituted on different benzene rings among the two benzene rings forming the fluorene skeleton may be different from each other, but are preferably the same. When m2a and m2b are 2 or more, the types of R ^2a and R ^2b substituted on the same benzene ring among the two benzene rings may be the same or different from each other. The substitution positions of R ^2a and R ^2b are not particularly limited, and they may be substituted at positions other than the substitution positions of the groups Y ^1a and Y ^1b .

The totals k1a+m2a and k1b+m2b of the numbers of substitutions in the two benzene rings forming the fluorene skeleton are, for example, integers from 0 to 4, preferably integers from 1 to 3, more preferably 1 or 2, and even more preferably 1. The totals k1a+m2a and k1b+m2b may be different from each other, but are preferably the same.

In the formula (Y2) showing monovalent groups (or hydroxyl group-containing groups) Y ^2a and Y ^2b bonded to the 9,9-positions of the fluorene skeleton, examples of the linear or branched alkylene group represented by A ¹ include linear or branched C _1-12 alkylene groups such as a methylene group, an ethylene group, a trimethylene group, a propylene group, a 1,2-butanediyl group, and a 2-methylpropane-1,3-diyl group. Preferred alkylene groups are linear or branched C _1-8 alkylene groups, specifically linear or branched C _1-6 alkylene groups such as methylene, ethylene, trimethylene, propylene and 2-methylpropane-1,3-diyl groups, more preferably linear or branched C 1-5 alkylene groups, still more preferably linear or branched C _1-4 alkylene groups, among which linear or branched C _2-4 alkylene _groups are preferred, and particularly trimethylene group is preferred.

Examples of the linear or branched alkylene group represented by ^A2 include linear or branched C2-6 alkylene groups such as ethylene, propylene, trimethylene, 1,2-butanediyl, 1,3-butanediyl, and tetramethylene. Preferred alkylene groups ^A2 are linear or branched _C2-4 alkylene groups, more preferably linear or branched _{C2-3 alkylene} groups, with ethylene and propylene being preferred, and ethylene being particularly preferred.

The repeat number n2 of the oxyalkylene group -(A ² O)- can be selected, for example, from the range of about 0 to 20, and preferred ranges are 0 to 15, 0 to 10, 0 to 8, 0 to 5, 0 to 3, 0 to 2, and 0 to 1, in the following stepwise order, and particularly 0. The repeat number n2 may be an average value (or an arithmetic mean value, or an arithmetic mean value), that is, the average number of moles added, and the range is the same as the range of integers described above, including the preferred embodiments. When n2 is 2 or more, the types of the two or more A ² in the (poly)oxyalkylene group -(A ² O) _n2 - may be different from each other, but are preferably the same.

The total number of repeating numbers n2 in ^Y2a and ^Y2b , i.e., the total number of oxyalkylene groups in one molecule of the diol compound represented by formula (1) (or the average value of the total number of moles added) [hereinafter, also simply referred to as the total number of n2] can be selected, for example, from the range of about 0 to 30, and preferred ranges are, in the following stepwise order, 0 to 20, 0 to 10, 0 to 6, 0 to 4, 0 to 2, more preferably 0 to 1, and particularly preferably 0. The total number of n2 may be an integer or the average value of the total number of moles added.

If the value of n2 or the total number of n2 is too large, the refractive index and heat resistance may decrease.

The total number of n2 can be measured by a conventional method. For example, when a diol compound in which n2 in Y ^2a and Y ^2b of formula (1) is 0 [a compound represented by formula (1A) described later] is subjected to an addition reaction of an alkylene oxide (alkylene carbonate or haloalkanol) to form a (poly)alkyleneoxy group [-(OA ² ) _n1 -], the total number of n2 is calculated as an arithmetic mean or arithmetic mean value from the ratio of the amount of the diol compound (or hydroxyl value) to the amount of the alkylene oxide (alkylene carbonate or haloalkanol) consumed in the reaction, specifically, the method described in JP 2013-53310 A.

Representative examples of the diol compound represented by the formula (1) include a diol compound in which k1a and k1b are 1, Z ¹ is a C _6-12 arene ring such as a benzene ring, a naphthalene ring, or a biphenyl ring, A ¹ is a linear or branched C _1-6 alkylene group, A ² is a linear or branched C _2-4 alkylene group, and n2 is 0 or 1 to 10; preferably, a diol compound in which k1a and k1b are 1, Z ¹ is a benzene ring or a naphthalene ring, A ¹ is a linear or branched C _1-4 alkylene group, A ² is a linear or branched C _2-3 alkylene group such as an ethylene group or a propylene group, and n2 is 0 or 1 to 6; more preferably, a diol compound in which k1a and k1b are 1, Z ¹ is a naphthalene ring, A ¹ is a linear or branched C A diol compound in which A is a _2-4 alkylene group, A ² is an ethylene group, and n2 is 0 or 1; among these, 9,9-bis(3-hydroxypropyl)-dinaphthylfluorenes such as 9,9-bis(3-hydroxypropyl)-di(1-naphthyl)fluorene and 9,9-bis(3-hydroxypropyl)-di(2-naphthyl)fluorene are preferred; and 9,9-bis(3-hydroxypropyl)-2,7-dinaphthylfluorenes such as 9,9-bis(3-hydroxypropyl)-2,7-di(2-naphthyl)fluorene are particularly preferred.

The diol compound represented by formula (1) has a high refractive index, and the refractive index nD at a temperature of 25°C and a wavelength of 589 nm may be, for example, about 1.7 to 1.8, and the preferred ranges are 1.73 to 1.78, 1.74 to 1.77, 1.745 to 1.765, and 1.75 to 1.76, in the following stepwise order.

The melting point of the diol compound represented by formula (1) may be, for example, about 100 to 250°C, and the preferred ranges are 150 to 240°C, 175 to 230°C, and 180 to 225°C, in the following stepwise order.

The 5% mass loss temperature of the diol compound represented by formula (1) may be, for example, about 250 to 500°C, and the preferred ranges are 350 to 450°C, 370 to 420°C, and 380 to 400°C, in the following stepwise order.

In this specification and claims, the refractive index, melting point, and 5% mass loss temperature of the diol compound represented by formula (1) can be measured by the method described in the examples below.

[Method for producing diol compound represented by formula (1)]
The method for producing the diol compound represented by the formula (1) is not particularly limited, but for example, a diol compound in which n2 in ^Y2a and ^Y2b in the formula (1) is 0 [also referred to as a compound represented by formula (1A)] may be prepared according to the following reaction scheme including a reduction step of subjecting a compound represented by the following formula (I) to a reduction reaction.

[In the formula, X ^1a and X ^2a , and X ^1b and X ^2b each independently represent a pair of reactive groups capable of forming a carbon-carbon bond (or a direct bond) by a coupling reaction,
^Y3a and ^Y3b each independently represent the following formula (Y3):

(In the formula, ^A3 represents a linear or branched alkylene group,
^R3 represents a hydrogen atom or an alkyl group.
represents a monovalent group represented by
Y ^1a and Y ^1b , k1a and k1b, R ^2a and R ^2b , m2a and m2b, and Y ^2a and Y ^2b (n2 in Y ^2a and Y ^2b is 0) are the same as those in the formula (1) including preferred embodiments thereof.

(Preparation of Compounds Represented by Formula (I))
The compound represented by formula (I) can be prepared by a coupling reaction (or a cross-coupling reaction) between the compound represented by formula (II) and the compounds represented by formulas (IIIa) and (IIIb).

Examples of coupling reactions include conventional coupling reactions, such as coupling reactions using palladium catalysts (or palladium(0) catalysts) such as the Suzuki-Miyaura coupling reaction, the Migita-Kosugi-Stille coupling reaction, the Negishi coupling reaction, and the Hiyama coupling reaction, and coupling reactions using nickel catalysts (or nickel(0) catalysts) such as the Kumada-Tamao-Corriu coupling reaction. Of these coupling reactions, the Suzuki-Miyaura coupling reaction is preferred.

In the formula (II), X ^1a and X ^1b each independently represent a reactive group capable of forming a carbon-carbon bond (or a direct bond) by a coupling reaction; in the formulas (IIIa) and (IIIb), X ^2a represents a reactive group capable of forming a carbon-carbon bond with X ^1a , and X ^2b represents a reactive group capable of forming a carbon-carbon bond with X ^1b by a coupling reaction. The reactive groups X ^1a and X ^1b , as well as X ^2a and X ^2b , can be appropriately selected according to the type of the coupling reaction. In the case of synthesis by the Suzuki-Miyaura coupling reaction, one of the reactive groups, for example, X ^1a and X ^1b , may be a halogen atom or a fluorinated alkane sulfonyloxy group. Examples of the halogen atom include an iodine atom, a bromine atom, and a chlorine atom. Examples of the fluorinated alkane sulfonyloxy group include a fluorinated C _1-4 alkane sulfonyloxy group such as a trifluoromethanesulfonyloxy group (or a group [-OTf]). These one reactive groups may be used alone or in combination of two or more. Among these one reactive groups, a halogen atom is preferred, an iodine atom or a bromine atom is more preferred, and a bromine atom is even more preferred. In addition, the types of X ^1a and X ^1b may be different from each other, but are preferably the same.

Examples of the other reactive groups X ^2a and X ^2b capable of coupling with the one reactive groups X ^1a and X ^1b in the Suzuki-Miyaura coupling reaction include a boronic acid group (dihydroxyboryl group or group [-B(OH) ₂ ]), a boronic acid ester group, and the like. Examples of the boronic acid ester group include dialkoxyboryl groups such as dimethoxyboryl group, diisopropoxyboryl group, and dibutoxyboryl group; and cyclic boronic acid ester groups such as pinacolatoboryl group (or group [-Bpin]), 1,3,2-dioxaborinane-2-yl group, and 5,5-dimethyl-1,3,2-dioxaborinane-2-yl group. These other reactive groups may be used alone or in combination of two or more kinds. Among the other reactive groups, the group [-B(OH) ₂ ] is preferred. The types of X ^2a and X ^2b may be different from each other, but are preferably the same.

The groups ^X1a and ^X1b , and the groups ^X2a and ^X2b may be any reactive groups as long as they are a pair of reactive groups capable of coupling reaction with each other. ^X1a and ^X1b may be the other reactive group such as a boronic acid group, and ^X2a and ^X2b may be one reactive group such as a halogen atom, but it is preferable that ^X1a and ^X1b are the one reactive group such as a halogen atom, and ^X2a and ^X2b are the other reactive group such as a boronic acid group.

In formula (Y3) showing monovalent groups ^Y3a and ^Y3b , the linear or branched alkylene group ^A3 is an alkylene group having one less carbon atom than ^A1 in formula (1). Representative alkylene groups ^A3 include linear or branched _C1-11 alkylene groups such as methylene, ethylene, trimethylene, propylene, 1,2-butanediyl, and 2-methylpropane-1,3-diyl, and are preferably _C1-5 alkylene, _C1-4 alkylene, and _C1-3 alkylene groups in the following order, with ethylene being particularly preferred.

Examples of the alkyl group represented by ^R3 include linear or branched _C1-6 alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, and t-butyl, preferably _C1-4 alkyl groups, more preferably _C1-3 alkyl groups, and particularly preferably _C1-2 alkyl groups such as methyl. ^R3 may be either a hydrogen atom or an alkyl group, but is preferably an alkyl group.

The compound represented by formula (II) above includes compounds corresponding to preferred embodiments of the diol compound represented by formula (1) above, such as 9,9-bis(alkoxycarbonylalkyl)dihalofluorene.

Examples of the 9,9-bis(alkoxycarbonylalkyl)dihalofluorene include 9,9-bis(C 1-4 alkoxy-carbonyl-C _2-6 alkyl)-dihalofluorenes such as 9,9-bis(2-methoxycarbonylethyl)-2,7-dibromofluorene, 9,9-bis(2-ethoxycarbonylethyl)-2,7-dibromofluorene, and 9,9-bis( _2- methoxycarbonylpropyl)-2,7-dibromofluorene. The 9,9-bis(alkoxycarbonylalkyl)dihalofluorene may be prepared, for example, in accordance with the method described in JP-A-2005-89422. Specifically, the 9-position unsubstituted dihalo-9H-fluorene, such as 2,7-dibromofluorene, may be reacted with an acrylic acid ester, such as methyl acrylate, or a haloacetic acid ester, such as methyl bromoacetate, in the presence of a base catalyst, such as trimethylbenzylammonium hydroxide.

The compound represented by formula (IIIa) and the compound represented by formula (IIIb) are compounds corresponding to the preferred embodiment of the diol compound represented by formula (1), such as phenylboronic acid, 1-naphthylboronic acid, and 2-naphthylboronic acid, with 2-naphthylboronic acid being preferred. The compound represented by formula (IIIa) and the compound represented by formula (IIIb) are preferably the same compound, and commercially available products can be used.

The ratio of the compound represented by formula (II) to the total amount of the compound represented by formula (IIIa) and the compound represented by formula (IIIb) may be, for example, the former/latter (molar ratio) = about 1/2 to 1/10, and the preferred ranges are 1/2.1 to 1/5 and 1/2.2 to 1/3.5 in the following stepwise order.

The coupling reaction may be carried out in the presence of a catalyst. When synthesizing by the Suzuki-Miyaura coupling reaction, the reaction may be carried out in the presence of a palladium catalyst, such as a conventional coupling catalyst, for example, a palladium (0) catalyst or a palladium (II) catalyst.

Examples of the palladium(0) catalyst include palladium(0)-phosphine complexes such as tetrakis(triphenylphosphine)palladium(0) [or Pd(PPh ₃ ) ₄ ] and bis(tri-t-butylphosphine)palladium(0) [or Pd(P(t-Bu) ₃ ) ₂ ].

Examples of the palladium (II) catalyst include palladium (II)-phosphine complexes such as [1,2-bis(diphenylphosphino)ethane]palladium (II) dichloride [or PdCl ₂ (dppe)], [1,3-bis(diphenylphosphino)propane]palladium (II) dichloride [or PdCl ₂ (dppp)], [1,1'-bis(diphenylphosphino)ferrocene]palladium (II) dichloride [or PdCl ₂ (dppf)], bis(triphenylphosphine)palladium (II) dichloride [or PdCl ₂ (PPh ₃ ) ₂ ], and bis(tri-o-tolylphosphine)palladium (II) dichloride [or PdCl ₂ (P(o-tolyl) ₃ ) ₂ ]. When a palladium (II) catalyst is used, the reaction is initiated by reduction to a zero-valent complex by a reducing compound in the reaction system, such as a phosphine, an amine, or an organometallic reagent.

The palladium catalyst may be prepared in situ by adding a catalyst precursor such as tris(dibenzylideneacetone)dipalladium(0) chloroform complex [or Pd ₂ (dba) _{3.CHCl 3} ] and a ligand such as a phosphine or a carbene.

These catalysts can be used alone or in combination of two or more. Among these catalysts, palladium(0)-phosphine complexes such as Pd(PPh ₃ ) ₄ are preferred. The proportion of the catalyst, calculated as metal, may be, for example, about 0.01 to 0.1 moles, preferably 0.03 to 0.07 moles, and more preferably 0.04 to 0.06 moles, per mole of the compound represented by formula (2).

The Suzuki-Miyaura coupling reaction may be carried out in the presence of a base. Examples of bases include metal carbonates or hydrogen carbonates, metal hydroxides, metal fluorides, metal phosphates, metal organic acid salts, and metal alkoxides.

Examples of metal carbonates or bicarbonates include alkali metal carbonates or bicarbonates such as sodium carbonate, potassium carbonate, cesium carbonate, and sodium bicarbonate, as well as thallium (I) carbonate.

Examples of metal hydroxides include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and cesium hydroxide, alkaline earth metal hydroxides such as barium hydroxide, and thallium(I) hydroxide.

Examples of metal fluorides include alkali metal fluorides such as potassium fluoride and cesium fluoride.

Examples of metal phosphates include alkali metal phosphates such as tripotassium phosphate.

Examples of metal organic acid salts include alkali metal acetates such as potassium acetate.

Examples of metal alkoxides include alkali metal alkoxides such as sodium methoxide, sodium ethoxide, and potassium t-butoxide.

These bases can be used alone or in combination of two or more. Preferred bases are metal carbonates such as sodium carbonate and potassium carbonate. The ratio of the base to 1 mole of the compound represented by formula (II) may be, for example, about 0.1 to 50 moles, preferably 1 to 10 moles, and more preferably 3 to 7 moles.

The coupling reaction may be carried out in the presence or absence of a phase transfer catalyst. Examples of phase transfer catalysts include tetraalkylammonium halides such as tetrabutylammonium bromide (TBAB) and trioctylmethylammonium chloride. These phase transfer catalysts may be used alone or in combination of two or more.

The coupling reaction may be carried out in the absence or presence of a solvent inert to the reaction. Examples of the solvent include water; alcohols such as methanol and ethanol; ethers such as cyclic ethers and chain ethers; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; nitriles such as acetonitrile and benzonitrile; amides such as N,N-dimethylformamide, dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxides such as dimethyl sulfoxide; and hydrocarbons such as aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons.

Examples of cyclic ethers include dioxane and tetrahydrofuran. Examples of chain ethers include dialkyl ethers such as diethyl ether and diisopropyl ether, and glycol ethers. Examples of glycol ethers include (poly)alkylene glycol monoalkyl ethers such as methyl cellosolve and methyl carbitol, and (poly)alkylene glycol dialkyl ethers such as dimethoxyethane.

Examples of aliphatic hydrocarbons include hexane and dodecane. Examples of alicyclic hydrocarbons include cyclohexane. Examples of aromatic hydrocarbons include toluene and xylene.

These solvents can be used alone or in combination of two or more. Of these solvents, a mixed solvent of water and an aromatic hydrocarbon such as toluene is preferred.

The coupling reaction may be carried out under an inert atmosphere, for example, nitrogen gas or a rare gas such as helium or argon. The reaction temperature is, for example, 50 to 200°C, preferably 60 to 100°C, and more preferably 70 to 80°C. The reaction time may be, for example, about 1 to 24 hours, and is preferably 3 to 12 hours.

After the reaction is completed, the reaction mixture may be separated and purified, if necessary, by conventional separation and purification methods, such as washing, extraction, filtration, dehydration, concentration, decantation, drying, crystallization, reprecipitation, column chromatography, adsorption, or a combination of these.

(Preparation of Compound Represented by Formula (1A) (or Reduction Step))
The diol compound represented by the formula (1A) (a compound in which n2 in ^Y2a and ^Y2b in formula (1) is 0) can be prepared by reducing the compound represented by the formula (I). A conventional reducing agent may be used for the reduction. Examples of the reducing agent include metal hydrides such as metal borohydrides, metal aluminum hydrides, boranes, aluminum hydrides, organosilicon compounds, and organotin compounds.

Examples of the metal borohydrides include alkali metal borohydrides; zinc borohydrides such as zinc borohydride (Zn(BH ₄ ) ₂ ); and the like. Examples of the alkali metal borohydrides include lithium borohydrides such as lithium borohydride (LiBH ₄ ), lithium triethylborohydride (LiBH(C ₂ H ₅ ) ₃ ), lithium tri-s-butylborohydride (LiBH(s-C ₄ H ₉ ) ₃ ), and lithium bis(2,4,6-trimethylphenyl)borohydride (LiBH(Mes) ₂ ); sodium borohydride (NaBH ₄ ), sodium cyanoborohydride (NaBH ₃ CN), sodium trimethoxyborohydride (NaBH(OCH ₃ ) ₃ ), sodium triacetoxyborohydride (NaBH(OCOCH ₃ ) ₃ ), and sodium borohydride sulfide (NaBH ₂ S _{3 ).} ), and potassium borohydrides such as potassium tri-s-butylborohydride (KBH(s-C ₄ H ₉ ) ₃ ).

Examples of the metal aluminum hydrides include alkali metal aluminum hydrides. Examples of the alkali metal aluminum hydrides include lithium aluminum hydrides such as lithium aluminum hydride (LiAlH ₄ ), lithium trimethoxyaluminum hydride (LiAlH(OCH ₃ ) ₃ ), and lithium tri-t-butoxyaluminum hydride (LiAlH(Ot-C ₄ H ₉ ) ₃ ); and sodium aluminum hydrides such as sodium aluminum hydride (NaAlH ₄ ), and sodium bis(2-methoxyethoxy)aluminum hydride ([(CH ₃ OCH ₂ CH ₂ O) ₂ AlH ₂ ]Na).

Examples of boranes include diborane; borane complexes such as borane-tetrahydrofuran complex and borane-dimethylsulfide complex; and 9-borabicyclo[3.3.1]nonane (9-BBN).

Examples of aluminum hydrides include aluminum hydride (AlH ₃ ) and diisobutylaluminum hydride ((iC ₄ H ₉ ) ₂ AlH).

Examples of organosilicon compounds include trialkylsilanes such as triethylsilane, diarylsilanes such as diphenylsilane, and aryldialkylsilanes such as phenyldimethylsilane.

Examples of organotin compounds include trialkylstannanes such as tri-n-butylstannane, dialkylstannanes such as di-n-butylstannane, and diarylstannanes such as diphenylstannane.

These reducing agents may be used alone or in combination of two or more. Preferred reducing agents are metal borohydrides such as alkali metal borohydrides, and more preferably sodium borohydrides such as sodium borohydride (NaBH ₄ ).

The amount of the reducing agent used is, for example, 2 to 10 moles, preferably 2.2 to 5 moles, and more preferably 2.5 to 3.5 moles, per mole of the compound represented by formula (I).

The reducing agent may be used together with other reagents (or activators) depending on the type thereof and the compound represented by formula (I), for example, when sodium borohydrides such as sodium borohydride (NaBH ₄ ) are used as the reducing agent, they may be used together with boron trifluoride ether complexes such as boron trifluoride diethyl ether complex, etc. The ratio of the activator is, for example, 0.1 to 10 mol, preferably 0.5 to 5 mol, and more preferably 0.8 to 1.2 mol relative to 1 mol of the reducing agent.

The reduction reaction may be carried out in the presence or absence of an inert solvent. Examples of the solvent include water; alcohols such as methanol, ethanol, and isopropanol; ethers, specifically, cyclic ethers such as dioxane and tetrahydrofuran (THF), chain ethers such as dialkyl ethers and glycol ethers; and hydrocarbons, specifically, aliphatic hydrocarbons such as hexane and dodecane, alicyclic hydrocarbons such as cyclohexane, and aromatic hydrocarbons such as benzene, toluene, and xylene. Examples of the dialkyl ethers include diethyl ether and diisopropyl ether, and examples of the glycol ethers include (poly)alkylene glycol monoalkyl ethers such as methyl cellosolve and methyl carbitol, and (poly)alkylene glycol dialkyl ethers such as dimethoxyethane.

The solvents may be used alone or in combination of two or more. Preferred solvents are ethers, and cyclic ethers such as THF are more preferred.

The reaction may be carried out under an inert gas atmosphere, for example, nitrogen or a rare gas such as helium or argon. The reaction temperature is, for example, 0 to 50°C, preferably 5 to 35°C. The reaction time is not particularly limited, and is, for example, about 1 to 48 hours, preferably 2 to 12 hours.

After the reaction is complete, the reducing agent may be quenched. Quenching may be performed by adding water, but it may also be gently quenched with acetone beforehand to suppress heat generation.

After the reaction is completed, the reaction mixture may be separated and purified, if necessary, by conventional separation and purification methods, such as washing, extraction, filtration, dehydration, drying, concentration, decantation, recrystallization, reprecipitation, chromatography, or a combination of these methods.

The diol compound represented by the formula (1A) thus obtained may be reacted with an alkylene oxide (alkylene carbonate or haloalkanol) corresponding to the alkylene group ^A2 in a ratio corresponding to the repeating number n2 by a conventional method to prepare the diol compound represented by the formula (1).

[Resin made from diol compound represented by formula (1)]
The resin (polymer or macromolecule) prepared using the diol compound represented by the formula (1) as a raw material is not particularly limited, and may be a heat- or light-curable resin. However, it is preferably a thermoplastic resin in that it is possible to adjust the moldability (fluidity or handleability) and heat resistance in a well-balanced manner.

The thermoplastic resin is not particularly limited as long as it contains at least the diol component (A) as a polymerization component, and examples thereof include polyester-based resins and thermoplastic polyurethane-based resins. From the viewpoint of an excellent balance between optical properties such as a high refractive index, low birefringence, and low Abbe number, and moldability, polyester-based resins are preferred.

The polyester resin may be any resin having at least an ester bond [including a carbonate bond (carbonate bond)] in the main chain skeleton, and examples thereof include polyester resin, polyester carbonate resin, polycarbonate resin, and the like. Among the polyester resins, polycarbonate resin is preferred in terms of excellent strength (or hardness) and good injection moldability; polyester resin is preferred in terms of excellent stretchability (flexibility or toughness) and good film moldability; polyester carbonate resin is preferred in terms of excellent balance between strength and stretchability, and good balance between injection moldability and film moldability; and polyester resin is most preferred in terms of excellent balance between high refractive index, high moldability, low birefringence, and low Abbe number.

Specific constituent units of the resin are sufficient if they contain at least diol units (A), and may further contain dicarboxylic acid units (B), carbonate units (C), etc.

(Diol Unit (A))
First Diol Unit (A1)
The diol unit (A) contains at least the structural unit represented by the formula (1P) as the first diol unit (A1).The structural unit represented by the formula (1P) corresponds to the first diol component represented by the formula (1), so Y1a and ^Y1b , k1a and k1b, ^R2a and ^R2b , m2a and ^m2b in the formula (1P) are the same as those in the formula (1) including preferred embodiments, and ^A1 , ^A2 and n2 in ^Y2c and ^Y2d are the same as ^those in the ^formula (1) including preferred embodiments.

Representative examples of the first diol unit (A1) include the diol units exemplified in the section on the diol compound represented by formula (1), including preferred embodiments. The first diol unit (A1) may be contained alone or in combination of two or more kinds.

In the resin of the present invention containing the first diol unit (A1), the refractive index can be significantly improved while suppressing an excessive increase in the glass transition temperature Tg (while maintaining or reducing Tg), and both a high refractive index and high moldability (fluidity or handleability) can be achieved. That is, in the fluorene ring of the formula (1P), the aryl group-containing group (groups Y ^1a and Y ^1b ), which is likely to increase the refractive index, is substituted at the 1-8 positions of the fluorene ring, instead of the 9 position as in the conventional diol compound having a 9,9-bisarylfluorene skeleton, and the 9 position is substituted with an alkylene group A ¹ instead of an aryl group, so that the above properties can be achieved at a higher level than in the past. In particular, as shown in the examples described later, it was an unexpected result that the first diol unit (A1) can effectively improve the refractive index and furthermore maintain or reduce Tg, even if the chemical structure contains the same number of benzene ring skeletons (aromatic ring skeletons) as in the conventional diol compound having a 9,9-bisarylfluorene skeleton.

The resin of the present invention also has an excellent balance between heat resistance and moldability, since moldability can be improved without significantly impairing heat resistance (without significantly lowering Tg), which is contrary to moldability. Furthermore, the inclusion of the first diol unit (A1) is also useful in that it can effectively reduce birefringence even when it contains many benzene ring skeletons (aromatic ring skeletons), and can also significantly reduce the Abbe number, and these properties can be achieved in a well-balanced manner along with the high refractive index and high moldability.

The proportion of the first diol units (A1) in the resin may be, for example, about 1 mol% or more relative to the total diol units (A), and preferred ranges are 5 to 100 mol%, 10 to 95 mol%, and 20 to 90 mol%, in the following stepwise order. If the proportion of the first diol units (A1) is too low, the refractive index and heat resistance may not be sufficiently improved, and conversely, if it is too high, the birefringence may become too negative, and the absolute value of the birefringence may not be sufficiently reduced.

The diol unit (A) may be composed of only the first diol unit (A1), but may further contain a different diol unit, for example, a second diol unit (A2) represented by the formula (2) or a second diol unit (A3) represented by the formula (3).

Second Diol Unit (A2)
The diol unit (A) may or may not contain the second diol unit (A2) represented by the above formula (2) as necessary. When the second diol unit (A2) is contained, the refractive index and heat resistance can be improved while suppressing an increase in birefringence.

In the formula (2), examples of the arene rings represented by Z ^2a and Z ^2b include the same arene rings as those exemplified for the ring Z ¹ described in the section on the diol compound represented by the formula (1). The types of rings Z ^2a and Z ^2b may be the same or different from each other, and are preferably the same. Among the rings Z ^2a and Z ^2b , C _6-12 arene rings such as benzene rings, naphthalene rings, and biphenyl rings are preferred, C _6-10 arene rings such as benzene rings and naphthalene rings are more preferred, and naphthalene rings are particularly preferred because they are more likely to have a high refractive index and a low Abbe number, and are excellent in balance with low birefringence and heat resistance. The types of Z ^2a and Z ^2b may be different from each other, but are preferably the same.

The substitution positions of rings ^Z2a and ^Z2b bonded to the 9-position of the fluorene ring are not particularly limited. For example, when rings ^Z2a and ^Z2b are naphthalene rings, the substitution positions are the 1- or 2-position, preferably the 2-position, and when rings ^Z2a and ^Z2b are biphenyl rings, the substitution positions are the 2-, 3- or 4-position, preferably the 3-position.

Examples of the substituent represented by ^R4 (non-reactive or non-polymerizable substituent) include hydrocarbon groups such as alkyl and aryl groups; cyano groups; and halogen atoms such as fluorine, chlorine, bromine, and iodine atoms. Examples of the alkyl group include linear or branched C _1-6 alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, and t-butyl groups. Examples of the aryl group include C _6-10 aryl groups such as phenyl groups. When m4 is 1 or more, the group ^R4 is preferably an alkyl group, a cyano group, or a halogen atom, more preferably an alkyl group, and particularly preferably a linear or branched C _1-4 alkyl group such as a methyl group.

The number of substitutions m4 of the group R ⁴ is, for example, an integer of about 0 to 6, and the preferred range is an integer of 0 to 4, an integer of 0 to 2, more preferably 0 or 1, particularly 0, in the following stepwise order. When m4 is 2 or more, the types of the two or more groups R ⁴ may be the same or different from each other. The substitution position of the group R ⁴ is not particularly limited, and examples thereof include 2-7 positions such as 2-position, 3-position and/or 7-position of the fluorene ring, and preferably 2-position or 2,7-position.

Examples of the substituents (non-reactive or non-polymerizable substituents) represented by R ^5a and R ^5b include the same groups as those exemplified as the substituents R ¹ described in the section on the diol compound represented by formula (1) (or the first diol unit (A1)). Representative groups among these groups R ^5a and R ^5b include halogen atoms; hydrocarbon groups such as alkyl groups, cycloalkyl groups, aryl groups, and aralkyl groups; alkoxy groups; acyl groups; nitro groups; cyano groups; and substituted amino groups. When the number of substitutions m5a and m5b is 1 or more, preferred groups R ^5a and R ^5b include alkyl groups, cycloalkyl groups, aryl groups, and alkoxy groups, and more preferred groups include linear or branched C _1-6 alkyl groups such as methyl groups, C _5-8 cycloalkyl groups such as cyclohexyl groups, C _6-14 aryl groups such as phenyl groups, and linear or branched C _1-4 alkoxy groups such as methoxy groups. Among these, alkyl groups and aryl groups are preferred, and particularly, linear or branched _C1-4 alkyl groups such as methyl groups and _C6-10 aryl groups such as phenyl groups are preferred. When the group ^R5a or ^R5b is an aryl group, the group ^R5a or ^R5b may form a ring assembly arene ring together with the ring ^Z3a or ^Z3b .

The numbers of substitutions m5a and m5b of the groups R ^5a and R ^5b can be appropriately selected depending on the types of the rings Z ^2a and Z ^2b , and may be an integer of 0 or more, for example, an integer of about 0 to 8, and the preferred ranges are, in the following stepwise order, integers of 0 to 4 and integers of 0 to 2, with 0 or 1 being more preferable, and 0 being particularly preferable.

The substitution numbers m5a and m5b may be different from each other, but are preferably the same. When the substitution numbers m5a and m5b are 2 or more, the types of the two or more R ^5a and R ^5b substituted on the same rings Z ^2a and Z ^2b may be the same or different from each other. The types of the groups R ^5a and R ^5b may be the same or different from each other. In particular, when m5a and m5b are 1, the rings Z ^2a and Z ^2b may be benzene rings, naphthalene rings or biphenyl rings, and the groups R ^5a and R ^5b may be methyl groups. The substitution positions of the groups R ^5a and R ^5b are not particularly limited as long as they are positions other than the bonding positions between the rings Z ^2a and Z ^2b and the ether bond (-O-) and the 9-position of the fluorene ring, and preferably they are substituted at the ortho position (the carbon atom adjacent to the bonding position of the ether bond) in the rings Z ^2a and Z ^2b with respect to the ether bond (-O-).

Examples of the alkylene groups A ^4a and A ^4b include linear or branched C _2-6 alkylene groups such as ethylene, propylene (1,2-propanediyl), trimethylene, 1,2-butanediyl and tetramethylene groups, and when the repeat numbers n4a and n4b are 1 or more, A ^4a and A ^4b are preferably linear or branched C _2-4 alkylene groups, more preferably C _2-3 alkylene groups such as ethylene and propylene, and particularly preferably ethylene. The types of A ^4a and A ^4b may be the same or different.

The repeat numbers (number of moles added) n4a and n4b of the oxyalkylene groups (-OA ^4a -) and (-OA ^4b -) may each be selected from the range of integers of 0 or more, for example, about 0 to 15, and preferred ranges are the following stepwise ranges of 0 to 10, 0 to 8, 0 to 6, 0 to 4, 0 to 2, and 0 to 1. Furthermore, the repeat numbers n4a and n4b are preferably 1 or more in terms of improving polymerization reactivity, and more preferred ranges are the following stepwise ranges of 1 to 15, 1 to 10, 1 to 8, 1 to 6, 1 to 4, 1 to 3, and 1 to 2, and 1 is particularly preferred.

In this specification and claims, the "repetition number (number of added moles)" may be an average value (arithmetic mean value, additive mean value) or an average number of added moles. The preferred embodiment of the average number of added moles of n4a and n4b is the same as the preferred range (range of integers) described above. If the repetition numbers n4a and n4b are too large, the refractive index and heat resistance may decrease.

Furthermore, the two repeat numbers n4a and n4b may be the same or different. When n4a and n4b are 2 or more, the types of the two or more oxyalkylene groups (-OA ^4a -) and (-OA ^4b -) may be the same or different.

The substitution positions of the groups [-O-(A ^4a O) _n4a -] and [-O-(A ^4b O) _n4b -] (also referred to as ether-containing groups) on the rings Z ^2a and Z ^2b are not particularly limited as long as they are substituted at appropriate positions on the rings Z ^2a and Z ^2b , respectively. When the rings Z ^2a and Z ^2b are benzene rings, the substitution position of the ether-containing group is preferably the 2-, 3- or 4-position, particularly the 3- or 4-position, and particularly the 4-position, of the phenyl group bonded to the 9-position of the fluorene ring. When rings Z ^2a and Z ^2b are naphthalene rings, the ether-containing group is preferably substituted at any one of the 5- to 8-positions of the naphthyl group bonded to the 9-position of the fluorene ring, for example, at the 1- or 2-position of the naphthalene ring relative to the 9-position of the fluorene ring (substitution in a 1-naphthyl or 2-naphthyl relationship), and is preferably substituted in a 1,5- or 2,6-position relationship, particularly 2,6-position relationship, relative to this substitution position. When rings Z ^2a and Z ^2b are ring-assembly arene rings, the substitution position of the ether-containing group is not particularly limited, and may be substituted, for example, on the arene ring bonded to the 9-position of the fluorene ring or on the arene ring adjacent to this arene ring. For example, when rings ^Z2a and ^Z2b are biphenyl rings (or rings ^Z2a and ^Z2b are benzene rings, m5a and m5b are 1, and ^R5a and ^R5b are phenyl groups), the 3- or 4-position of the biphenyl ring, preferably the 3-position, may be bonded to the 9-position of the fluorene ring, and when the 3-position of the biphenyl ring is bonded to the 9-position of the fluorene ring, the substitution position of the ether-containing group is, for example, the 2-, 4-, 5-, 6-, 2'-, 3'- or 4'-position of the biphenyl ring, preferably the 6- or 4'-position, and particularly preferably the 6-position.

Examples of the second diol component corresponding to the second diol unit (A2) include 9,9-bis(hydroxyaryl)fluorenes in which n4a and n4b are 0 in the above formula (2); and 9,9-bis[hydroxy(poly)alkoxyaryl]fluorenes in which n4a and n4b are 1 or more, for example, about 1 to 10.

In this specification and claims, unless otherwise specified, the term "(poly)alkoxy" is used to include both alkoxy groups and polyalkoxy groups.

Examples of 9,9-bis(hydroxyaryl)fluorenes include 9,9-bis(hydroxyphenyl)fluorene, 9,9-bis(alkyl-hydroxyphenyl)fluorene, 9,9-bis(aryl-hydroxyphenyl)fluorene, and 9,9-bis(hydroxynaphthyl)fluorene.

Examples of 9,9-bis(hydroxyphenyl)fluorene include 9,9-bis(4-hydroxyphenyl)fluorene.

Examples of the 9,9-bis(alkyl-hydroxyphenyl)fluorene include 9,9-bis[(mono- or di-)C _1-4 alkyl-hydroxyphenyl]fluorenes such as 9,9-bis(4-hydroxy-3-methylphenyl)fluorene and 9,9-bis(4-hydroxy-3,5-dimethylphenyl)fluorene.

Examples of the 9,9-bis(aryl-hydroxyphenyl)fluorene include 9,9-bis(C _6-10 aryl-hydroxyphenyl)fluorenes such as 9,9-bis(4-hydroxy-3-phenylphenyl)fluorene.

Examples of 9,9-bis(hydroxynaphthyl)fluorene include 9,9-bis(6-hydroxy-2-naphthyl)fluorene and 9,9-bis(5-hydroxy-1-naphthyl)fluorene.

Examples of 9,9-bis[hydroxy(poly)alkoxyaryl]fluorenes include 9,9-bis[hydroxy(poly)alkoxyphenyl]fluorene, 9,9-bis[alkyl-hydroxy(poly)alkoxyphenyl]fluorene, 9,9-bis[aryl-hydroxy(poly)alkoxyphenyl]fluorene, and 9,9-bis[hydroxy(poly)alkoxynaphthyl]fluorene.

Examples of the 9,9-bis[hydroxy(poly)alkoxyphenyl]fluorene include 9,9-bis[hydroxy(mono- to deca)C _2-4 alkoxy-phenyl]fluorenes such as 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxypropoxy)phenyl]fluorene, and 9,9-bis[4-(2-(2-hydroxyethoxy)ethoxy)phenyl]fluorene.

Examples of the 9,9-bis[alkyl-hydroxy(poly)alkoxyphenyl]fluorene include 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-hydroxypropoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-(2-hydroxyethoxy)ethoxy)-3-methylphenyl]fluorene, and 9,9-bis[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]fluorene, and other 9,9-bis[(mono or di)C _1-4 alkyl-hydroxy(mono to deca)C _2-4 alkoxy-phenyl]fluorenes.

Examples of the 9,9-bis[aryl-hydroxy(poly)alkoxyphenyl]fluorene include 9,9-bis[C 6-10 aryl-hydroxy(mono- to deca)C 2-4 alkoxy-phenyl]fluorenes such as 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-(2-hydroxypropoxy)-3- _phenylphenyl )fluorene, and 9,9-bis[4-(2-(2-hydroxyethoxy)ethoxy) _-3 -phenylphenyl]fluorene.

Examples of the 9,9-bis[hydroxy(poly)alkoxynaphthyl]fluorene include 9,9-bis[hydroxy(mono- to deca)C 2-4 alkoxy-naphthyl]fluorenes such as 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene, 9,9-bis[6-(2-hydroxypropoxy)-2-naphthyl]fluorene, 9,9-bis[6-(2-(2-hydroxyethoxy)ethoxy)-2-naphthyl]fluorene, and 9,9-bis[5-(2-hydroxyethoxy) _-1 -naphthyl]fluorene.

These second diol units (A2) may be contained alone or in combination of two or more kinds. Of the second diol units (A2), preferred are 9,9-bis[hydroxy(poly) _alkoxyaryl ]fluorenes such as _9,9 -bis[hydroxy(mono- to hexa)C2-4alkoxyC6-10aryl]fluorene; more preferred are 9,9-bis[hydroxy(mono- or di) _{C2-4alkoxyC6-10aryl} ]fluorene; and even more preferred are 9,9-bis[hydroxyC2-3alkoxy- _C6-10aryl ]fluorene such as 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene, and 9,9-bis[6-(2-hydroxyethoxy) _-2 -naphthyl]fluorene. _6-12 aryl]fluorene, and in particular, a structural unit derived from 9,9-bis[hydroxy C _2-3 alkoxynaphthyl]fluorene such as 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene is preferred because of its excellent balance of high refractive index, low birefringence, and high heat resistance.

Third Diol Unit (A3)
The diol unit (A) may or may not contain the third diol unit (A3) represented by the above formula (3) as necessary. When the third diol unit (A3) is contained, the polymerization reactivity is increased and the molecular weight is easily increased. In addition, the excessive increase in the glass transition temperature may be suppressed, and the moldability and handling properties may be improved.

In the formula (3), examples of the alkylene group represented by ^A5 include linear or branched _C2-12 alkylene groups such as ethylene, propylene, trimethylene, 1,2-butanediyl, 1,3-butanediyl, tetramethylene, 1,5-pentanediyl, 1,6-hexanediyl, 1,8-octanediyl, and 1,10-decanediyl. Preferred alkylene groups ^A5 are, in the following order, linear or branched _C2-10 alkylene groups, _C2-8 alkylene groups, _C2-6 alkylene groups, and _C2-4 alkylene groups, more preferably _C2-3 alkylene groups such as ethylene and propylene, and particularly preferably ethylene.

The repeat number n5 can be selected, for example, from the range of about 1 to 10, and preferred ranges are 1 to 6, 1 to 4, and 1 to 2 in the following stepwise order, with 1 being particularly preferred. The repeat number n5 may be an average value (arithmetic mean value or additive mean value), and preferred aspects are the same as those of the range of integers described above. When n5 is 2 or more, the types of the two or more oxyalkylene groups (-A ⁵ O-) may be different from each other, but are preferably the same.

Examples of the third diol component corresponding to the third diol unit (A3) include alkanediols (or alkylene glycols), polyalkanediols (or polyalkylene glycols), etc.

Examples of the alkylene glycol include compounds in which n5 is 1 and ^A5 corresponds to the alkylene group exemplified in formula (3), specifically, linear or branched C2-12 alkylene glycols such as ethylene glycol, propylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, tetramethylene glycol (or 1,4-butanediol), 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, and _1,10 -decanediol, and preferred embodiments are similar to those corresponding to the alkylene group ^A5 .

The polyalkylene glycol is a compound in which n5 in the above formula (3) is 2 or more, for example, about 2 to 10, and ^A5 corresponds to the above-mentioned alkylene group, specifically, di- to deca-linear or branched _C2-12 alkylene glycols such as diethylene glycol, dipropylene glycol, and triethylene glycol, preferably di- to hexa- _C2-6 alkylene glycol, and more preferably di- to tetra- _C2-4 alkylene glycol.

These third diol units (A3) may be contained alone or in combination of two or more. A preferred third diol unit (A3) is an alkylene glycol, from the viewpoint of difficulty in significantly reducing the refractive index, more preferably a linear or branched C _2-6 alkylene glycol such as ethylene glycol or 1,5-pentanediol, still more preferably a C _2-4 alkylene glycol such as ethylene glycol, propylene glycol, or 1,4-butanediol, among which a C _2-3 alkylene glycol such as ethylene glycol or propylene glycol, and particularly preferably a structural unit derived from ethylene glycol.

Fourth Diol Unit (A4)
The diol unit (A) may or may not contain a fourth diol unit (A4) different from the first to third diol units (A1) to (A3) as necessary.

Examples of the fourth diol unit (A4) include alicyclic diols, aromatic diols (excluding the first diol unit (A1) and the second diol unit (A2)), and structural units derived from alkylene oxide (alkylene carbonate or haloalkanol) adducts of these diol components.

Examples of alicyclic diols include cycloalkane diols such as cyclohexanediol; bis(hydroxyalkyl)cycloalkanes such as cyclohexanedimethanol; and hydrogenated aromatic diols such as hydrogenated bisphenol A, which are listed below.

Examples of aromatic diols include dihydroxyarenes such as hydroquinone and resorcinol; aromatic aliphatic diols such as benzenedimethanol; bisphenols such as bisphenol A, bisphenol F, bisphenol AD, bisphenol C, bisphenol G, and bisphenol S; and biphenols such as p,p'-biphenol.

Examples of the alkylene oxide (corresponding alkylene carbonate or haloalkanol) adduct of these diol components include a _C2-4 alkylene oxide adduct, preferably a _C2-3 alkylene oxide adduct such as an ethylene oxide adduct or a propylene oxide adduct, and the number of moles added is not particularly limited. Specific examples include an adduct in which about 2 to 10 moles of ethylene oxide are added to 1 mole of a diol such as bisphenol A.

The diol unit (A) may contain these fourth diol units (A4) alone or in combination of two or more. The proportion of the fourth diol unit (A4) may be selected from the range of, for example, 50 mol% or less (0 to 50 mol%), specifically about 0.1 to 30 mol%, based on the total diol unit (A). Preferred ranges are 20 mol% or less, 10 mol% or less, and 5 mol% or less in the following stepwise order, and it is preferable that the fourth diol unit (A4) is not substantially contained.

(Dicarboxylic acid unit (B))
The resin may or may not contain dicarboxylic acid units (B) as required, which can be combined with diol units (A) to form the polyester or polyester carbonate resins.

First Dicarboxylic Acid Unit (B1)
The dicarboxylic acid unit (B) does not necessarily contain the first dicarboxylic acid unit (B1) represented by the above formula (4), but may contain it as necessary. When the first dicarboxylic acid unit (B1) is contained, it is easy to reduce the birefringence (or adjust it to the negative (-) side) while maintaining a relatively high refractive index.

In the formula (4), the substituent represented by ^R6 (non-reactive substituent or non-polymerizable substituent) and the number of substitutions m6 thereof are the same as the substituents, ranges, and substitution positions exemplified as ^R4 and m4 in the formula (2) in the section on the second diol unit (A2), including preferred embodiments thereof.

Examples of the linear or branched alkylene group represented by A ^6a and A ^6b include the same alkylene groups as those exemplified as A ¹ in the section on the diol compound represented by formula (1), and are preferably C _1-6 alkylene groups such as methylene, ethylene, trimethylene, propylene, and 2-methylpropane-1,3-diyl, more preferably C _1-4 alkylene groups, and even more preferably C _2-4 alkylene groups, and among these, C _2-3 alkylene groups such as ethylene and propylene are preferred, and in particular ethylene groups are preferred. The types of A ^6a and A ^6b may be different from each other, but are preferably the same.

Examples of the first dicarboxylic acid component for forming the first dicarboxylic acid unit (B1) include 9,9-bis(carboxy C _2-6 alkyl)fluorenes such as 9,9-bis(2-carboxyethyl)fluorene and 9,9-bis(2-carboxypropyl)fluorene, and ester-forming derivatives thereof. A preferred first dicarboxylic acid unit (B1) is 9,9-bis(carboxy C _2-4 alkyl)fluorene, more preferably 9,9-bis(carboxy C _2-3 alkyl)fluorenes such as 9,9-bis(2-carboxyethyl)fluorene and 9,9-bis(2-carboxypropyl)fluorene, and particularly preferably contains a structural unit derived from 9,9-bis(2-carboxyethyl)fluorene. These first dicarboxylic acid units (B1) may be used alone or in combination of two or more.

Second Dicarboxylic Acid Unit (B2)
The dicarboxylic acid unit (B) does not necessarily contain the second dicarboxylic acid unit (B2) represented by the above formula (5), but may contain it as necessary. When the second dicarboxylic acid unit (B2) is contained, the birefringence can be adjusted to the plus (+) side (or positive side) while maintaining a relatively high refractive index and glass transition temperature.

In the formula (5), examples of the arene ring represented by ring ^Z3 include the same arene rings as ring ^Z1 described in the section on the diol compound represented by formula (1). Preferred examples of ring ^Z3 include _C6-12 arene rings such as a benzene ring, a naphthalene ring, and a biphenyl ring, and more preferred are _C6-10 arene rings such as a benzene ring and a naphthalene ring, with a naphthalene ring being particularly preferred from the viewpoint of easiness in improving the refractive index.

The substituent represented by ^R7 (non-reactive or non-polymerizable substituent) is the same as the substituent exemplified as ^R1 described in the section on the diol compound represented by formula (1), including preferred embodiments. When ^R7 is an aryl group, ^R7 may form a ring assembly arene ring together with ring ^Z3 .

The number of substitutions m7 of ^R7 can be selected according to the type of ring ^Z3 , and is, for example, an integer of about 0 to 6, preferably an integer of 0 to 4, an integer of 0 to 2, more preferably 0 or 1, particularly 0, in a stepwise manner. When m7 is 2 or more, the types of the two or more groups ^R7 may be the same or different from each other. In addition, the substitution position of the group ^R7 is not particularly limited, and it is sufficient that it is substituted at a position other than the bonding position between the two carbonyl groups [-C(=O)-] and ring ^Z3 .

The substitution positions of the two carbonyl groups [-C(=O)-] are not particularly limited, and for example, when ring ^Z3 is a benzene ring, the two carbonyl groups [-C(=O)-] may be substituted at the o-position, m-position or p-position, and among these, it is preferable that they are substituted at the m-position or p-position, and particularly preferably at the p-position. When ring ^Z3 is a naphthalene ring, the two carbonyl groups [-C(=O)-] are often substituted at any of the 1-8 positions, for example, in a naphthyl group in which one carbonyl group is substituted at the 1- or 2-position, the other carbonyl group is substituted at the 5- or 8-position, and preferably at the 1,5 or 2,6 positions, and particularly preferably at the 2,6 positions. When ring ^Z3 is a biphenyl ring, the two carbonyl groups [-C(=O)-] may be substituted in any positional relationship, but are preferably substituted on different benzene rings, more preferably at the 2,2'-positions, 3,3'-positions or 4,4'-positions, particularly preferably at the 2,2'-positions or 4,4'-positions.

Representative examples of the second dicarboxylic acid component corresponding to the second dicarboxylic acid unit (B2) include benzenedicarboxylic acids corresponding to the unit in which ring ^Z3 in the formula (5) is a benzene ring; polycyclic arenedicarboxylic acids corresponding to the unit in which ring ^Z3 is a polycyclic arene ring; and ester-forming derivatives thereof.

Examples of benzene dicarboxylic acids include benzene dicarboxylic acid, alkyl benzene dicarboxylic acid, etc. Examples of benzene dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, etc. Examples of alkyl benzene dicarboxylic acids include C _1-4 alkyl-benzene dicarboxylic acids such as 5-methylisophthalic acid, etc.

Examples of polycyclic arene dicarboxylic acids include condensed polycyclic arene dicarboxylic acids and ring-assembled arene dicarboxylic acids.

Examples of the condensed polycyclic arene dicarboxylic acid include naphthalene dicarboxylic acids such as 1,2-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, and 2,6-naphthalene dicarboxylic acid; anthracene dicarboxylic acid; and condensed polycyclic C _10-24 arene-dicarboxylic acids such as phenanthrene dicarboxylic acid. A preferred condensed polycyclic arene dicarboxylic acid is a condensed polycyclic C _10-14 arene-dicarboxylic acid.

Examples of the ring-assembled arene dicarboxylic acids include biC _6-10 arene-dicarboxylic acids such as 2,2'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, and 4,4'-biphenyldicarboxylic acid, with biphenyldicarboxylic acid being preferred.

The second dicarboxylic acid unit (B2) derived from these second dicarboxylic acid components may be used alone or in combination of two or more. Among these second dicarboxylic acid units (B2), units derived from benzene dicarboxylic acid components such as isophthalic acid and terephthalic acid, and biphenyl dicarboxylic acid components such as 2,2'-biphenyl dicarboxylic acid may be used. However, from the viewpoint of easiness in improving the refractive index and heat resistance, condensed polycyclic arene dicarboxylic acid components such as condensed polycyclic C _10-14 arene-dicarboxylic acid are preferred, and more preferably dicarboxylic acid units derived from naphthalene dicarboxylic acid, particularly 2,6-naphthalene dicarboxylic acid.

Third Dicarboxylic Acid Unit (B3)
The dicarboxylic acid unit (B) may or may not contain a third dicarboxylic acid unit (B3) different from the first dicarboxylic acid unit (B1) and the second dicarboxylic acid unit (B2), as necessary.

Examples of the third dicarboxylic acid unit (B3) include structural units derived from an aliphatic dicarboxylic acid component, an alicyclic dicarboxylic acid component, an aromatic dicarboxylic acid component (excluding the first dicarboxylic acid unit (B1) and the second dicarboxylic acid unit (B2)), etc.

Examples of the aliphatic dicarboxylic acid component include alkane dicarboxylic acids, specifically, C _2-12 alkane-dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and decanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids, specifically, C _2-10 alkene-dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, and ester-forming derivatives thereof.

Examples of the alicyclic dicarboxylic acid component include cycloalkane dicarboxylic acids, specifically, C _5-10 cycloalkane-dicarboxylic acids such as 1,4-cyclohexane dicarboxylic acid; bridged cyclic cycloalkane dicarboxylic acids, specifically, di- or tricycloalkane dicarboxylic acids such as decalin dicarboxylic acid, norbornane dicarboxylic acid, adamantane dicarboxylic acid, tricyclodecane dicarboxylic acid; cycloalkene dicarboxylic acids, specifically, C _5-10 cycloalkene-dicarboxylic acids such as cyclohexene dicarboxylic acid; bridged cyclic cycloalkene dicarboxylic acids, specifically, di- or tricycloalkene dicarboxylic acids such as norbornene dicarboxylic acid; and ester-forming derivatives thereof.

Examples of the aromatic dicarboxylic acid component include diarylalkanedicarboxylic acids, specifically, diC _6-10 aryl C _1-6 alkane-dicarboxylic acids such as 4,4'-diphenylmethanedicarboxylic acid; diarylketonedicarboxylic acids, specifically, di(C _6-10 aryl)ketone-dicarboxylic acids such as 4.4'-diphenylketonedicarboxylic acid; and ester-forming derivatives thereof.

These third dicarboxylic acid units (B3) may be used alone or in combination of two or more. The proportion of the third dicarboxylic acid units (B3) may be selected from the range of, for example, 50 mol% or less, specifically, about 0 to 30 mol%, based on the total dicarboxylic acid units (B). Preferred ranges are 20 mol% or less, 10 mol% or less, and 5 mol% or less in the following stepwise order, and it is preferable that the third dicarboxylic acid units (B3) are substantially not included.

(Carbonate Unit (C))
The resin may or may not contain carbonate units (C) as required, which can be combined with diol units (A) to form the polycarbonate or polyester carbonate resin.

The carbonate component (or carbonate bond forming component) for forming the carbonate unit (C) may be any compound capable of forming a carbonate bond by reaction with a compound (polymerization component) having a hydroxyl group such as the diol component (A). Representative carbonate components include, for example, phosgenes such as phosgene and triphosgene, and carbonate diesters such as diphenyl carbonate. From the viewpoint of safety, etc., carbonate diesters such as diphenyl carbonate are preferred. The carbonate components may be used alone or in combination of two or more.

In this specification and claims, the term "carbonate unit" refers to a structural unit derived from the carbonate component (carbonate bond forming component), i.e., a carbonyl group [-C(=O)-]. In other words, this carbonate unit (carbonyl group) bonds with a structural unit corresponding to the compound (polymerization component) having a hydroxyl group, such as a diol unit (A), to form a carbonate bond together with the terminal oxygen atoms (oxygen atoms derived from hydroxyl groups) of two adjacent structural units.

(Other structural units (D))
The resin does not need to contain any other structural unit (D) different from the diol unit (A), the dicarboxylic acid unit (B), and the carbonate unit (C). However, if necessary, the resin may contain such a structural unit (D) within a range that does not impair the effects of the present invention.

Other structural units (D) include, for example, structural units derived from hydroxyalkanoic acids and corresponding lactones, and polyfunctional polymerization components having three or more carboxyl groups and/or hydroxyl groups.

Examples of the hydroxyalkanoic acids and corresponding lactones include hydroxyalkanoic acids such as lactic acid, 3-hydroxybutyric acid, and 6-hydroxyhexanoic acid; lactones corresponding to hydroxyalkanoic acids such as ε-caprolactone, etc.

Examples of the polyfunctional polymerization component include polyfunctional polymerization components having a total of three or more carboxyl groups and/or hydroxyl groups, such as trivalent or higher polycarboxylic acids such as trimellitic acid and pyromellitic acid, and trivalent or higher polyhydric alcohols such as glycerin and pentaerythritol.

Such other structural units (D) may be included alone or in combination of two or more. The proportion of the other structural units (D) relative to the total amount of structural units (total amount of diol units (A), dicarboxylic acid units (B), carbonate units (C) and other structural units (D)) is, for example, 50 mol% or less (0 to 50 mol%), with preferred ranges being 30 mol% or less, 10 mol% or less, and 5 mol% or less in the following stepwise order, and it is usually preferable that the other structural units (D) are not substantially included. The proportion may be, for example, about 0.01 to 1 mol%.

(Preferable composition of polyester resin)
The resin of the present invention is preferably a polyester-based resin described in the following (1) to (3), since it can simultaneously achieve a high refractive index and high moldability at a high level and further has an excellent balance of low birefringence, heat resistance, and low Abbe number.

(1) Polycarbonate Resin The polycarbonate resin of the present invention is formed from a constituent unit containing the diol unit (A) containing at least the first diol unit (A1) and the carbonate unit (C). In addition, the polycarbonate resin preferably further contains a second diol unit (A2) as the diol unit (A).

Preferred units in the first diol unit (A1) and the second diol unit (A2) are the same as those in the preferred embodiments described above. Particularly preferred combinations of structural units forming a polycarbonate resin include a combination of a structural unit derived from 9,9-bis(hydroxyC _2-4 alkyl)-dinaphthylfluorene such as 9,9-bis(3-hydroxypropyl)-2,7-di(2-naphthyl)fluorene as the first diol unit (A1) and a structural unit derived from 9,9-bis[hydroxyC 2-4 alkoxy-naphthyl]fluorene such as 9,9-bis[6-(2-hydroxyethoxy)-2 _- naphthyl]fluorene as the second diol unit (A2).

The proportion of the first diol unit (A1) in the polycarbonate resin may be selected from the range of, for example, about 1 to 100 mol% relative to the total diol unit (A), and the preferred ranges are 10 to 90 mol%, 20 to 80 mol%, 30 to 70 mol%, 40 to 60 mol%, and 45 to 55 mol%, in the following stepwise order. In addition, in terms of an excellent balance of high moldability, high refractive index, low Abbe number, and low birefringence, the preferred ranges of the proportions are 50 to 80 mol%, 53 to 70 mol%, and 55 to 65 mol%, in the following stepwise order. If the proportion of the first diol unit (A1) is too small, the refractive index and heat resistance may not be sufficiently improved, and conversely, if it is too large, the birefringence may become large on the negative (minus) side, and the absolute value of the birefringence may not be sufficiently reduced.

The total proportion of the first diol unit (A1) and the second diol unit (A2) may be selected, for example, from a range of about 1 to 100 mol% relative to the total diol unit (A). Preferred ranges are, in the following stepwise order, 10 mol% or more, 30 mol% or more, 50 mol% or more, 70 mol% or more, 90 mol% or more, and substantially 100 mol% is preferred. If the total proportion is too small, the refractive index and moldability may not be sufficiently improved.

When the second diol unit (A2) is contained, the ratio A1/A2 of the first diol unit (A1) to the second diol unit (A2) may be selected, for example, from a range of about 1/99 to 99/1 (molar ratio) of the former/latter, and preferred ranges are 10/90 to 90/10, 20/80 to 80/20, 30/70 to 70/30, 40/60 to 60/40, and 45/55 to 55/45 in the following stepwise manner. The ratio A1/A2 is also preferably 50/50 to 90/10, 60/40 to 85/15, and 70/30 to 80/20 in the following stepwise manner. Furthermore, in terms of achieving an excellent balance between high moldability, high refractive index, low Abbe number, and low birefringence, the preferred ranges of the ratio A1/A2 are 50/50 to 80/20, 53/47 to 70/30, and 55/45 to 65/35, in the following stepwise order. If the ratio of the first diol unit (A1) is too small, the refractive index may not be sufficiently improved, the Tg may be too high, resulting in reduced moldability, and the Abbe number may not be reduced. If the ratio of the second diol unit (A2) is too small, the birefringence may not be reduced, and heat resistance may be reduced.

The ratio of diol units (A) to carbonate units (C) in the polycarbonate resin is the former/latter (molar ratio) = 1/0.8 to 1/1.2, preferably 1/0.9 to 1/1.1, and more preferably approximately equimolar.

The total proportion of the diol unit (A) and the carbonate unit (C) may be selected, for example, from the range of about 50 to 100 mol% relative to all the constituent units forming the polycarbonate resin, and is preferably 70 mol% or more, more preferably 90 mol% or more, and is particularly preferably substantially 100 mol%.

(2) Polyester carbonate resin The polyester carbonate resin of the present invention is formed from structural units including the diol unit (A) containing at least the first diol unit (A1), the dicarboxylic acid unit (B), and the carbonate unit (C). A preferred polyester carbonate resin further contains the second diol unit (A2) as the diol unit (A), and contains the first dicarboxylic acid unit (B1) as the dicarboxylic acid unit (B).

The preferred units in the first and second diol units (A1), (A2) and the first dicarboxylic acid unit (B1) are the same as those in the preferred embodiments described above. Particularly preferred combinations of structural units forming the polyester carbonate resin include a combination of a structural unit derived from 9,9-bis(hydroxyC _2-4 alkyl)-dinaphthylfluorene such as 9,9-bis(3-hydroxypropyl)-2,7-di(2-naphthyl)fluorene as the first diol unit (A1), a structural unit derived from 9,9-bis[hydroxyC _2-4 alkoxy-naphthyl]fluorene such as 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene as the second diol unit (A2), and a structural unit derived from 9,9-bis(carboxyC _2-4 alkyl)fluorene such as 9,9-bis(2-carboxyethyl)fluorene as the first dicarboxylic acid unit (B1).

The proportion of the first diol unit (A1) in the polyester carbonate resin may be selected, for example, from the range of about 1 to 100 mol% relative to the total diol unit (A), with preferred ranges being 5 to 60 mol%, 10 to 50 mol%, 20 to 45 mol%, and 25 to 40 mol%, in the following stepwise order. If the proportion of the first diol unit (A1) is too low, the refractive index and heat resistance may not be sufficiently improved, and conversely, if it is too high, the birefringence may become too negative, and the absolute value of the birefringence may not be sufficiently reduced.

The total proportion of the first diol unit (A1) and the second diol unit (A2) may be selected, for example, from a range of about 1 to 100 mol% relative to the total diol unit (A). Preferred ranges are, in the following stepwise order, 10 mol% or more, 30 mol% or more, 50 mol% or more, 70 mol% or more, 90 mol% or more, and substantially 100 mol% is preferred. If the total proportion is too small, the refractive index and moldability may not be sufficiently improved.

When the second diol unit (A2) is contained, the ratio A1/A2 of the first diol unit (A1) to the second diol unit (A2) may be selected, for example, from the range of about 1/99 to 99/1 (molar ratio) of the former/latter, and the preferred ranges are 5/95 to 60/40, 10/90 to 50/50, 20/80 to 45/55, and 25/75 to 40/60 in the following stepwise order. If the ratio of the first diol unit (A1) is too small, the refractive index may not be sufficiently improved, the Tg may be too high, resulting in reduced moldability, and the Abbe number may not be reduced. If the ratio of the second diol unit (A2) is too small, the birefringence may not be reduced, the heat resistance may be reduced, and the molecular weight may not be sufficiently improved.

When the first dicarboxylic acid unit (B1) is contained, the proportion of the first dicarboxylic acid unit (B1) may be selected, for example, from the range of about 1 to 100 mol% based on the total dicarboxylic acid unit (B), and preferred ranges are 10 to 100 mol%, 30 to 100 mol%, 50 to 100 mol%, 70 to 100 mol%, and 90 to 100 mol%, with substantially 100 mol% being preferred. If the proportion of the first dicarboxylic acid unit (B1) is too small, there is a risk that the birefringence cannot be sufficiently reduced.

The ratio of diol units (A) to the total amount of dicarboxylic acid units (B) and carbonate units (C) in the polyester carbonate resin is the former/latter (molar ratio) = 1/0.8 to 1/1.2, preferably 1/0.9 to 1/1.1, and more preferably approximately equimolar.

The ratio of dicarboxylic acid units (B) may be selected from the range of, for example, about 0.01 to 0.99 moles per mole of diol units (A), and preferred ranges are 0.1 to 0.9 moles, 0.5 to 0.85 moles, 0.55 to 0.8 moles, and 0.6 to 0.75 moles in the following stepwise order. If the ratio of dicarboxylic acid units (B) is too high or too low, it may not be possible to achieve a good balance of properties such as high refractive index, high moldability, low birefringence, low Abbe number, and heat resistance. If the ratio of dicarboxylic acid units (B) is too high, the strength (or hardness) may decrease, resulting in a decrease in injection moldability, and if it is too low, the flexibility (or toughness) may decrease, resulting in a decrease in film moldability.

The total proportion of the diol units (A), dicarboxylic acid units (B) and carbonate units (C) may be selected, for example, from a range of about 50 to 100 mol% relative to the total constituent units forming the polyester carbonate resin, and is preferably 70 mol% or more, more preferably 90 mol% or more, and is particularly preferably substantially 100 mol%.

(3) Polyester resin The polyester resin of the present invention is formed of a structural unit containing a diol unit (A) containing at least the first diol unit (A1) and the dicarboxylic acid unit (B). A preferred polyester resin further contains the third diol unit (A3) as the diol unit (A) and the first dicarboxylic acid unit (B1) as the dicarboxylic acid unit (B). The diol unit (A) may further contain the second diol unit (A2) in addition to the first diol unit (A1) and the third diol unit (A3). A more preferred polyester resin further contains the second dicarboxylic acid unit (B2) in addition to the units (A1), (A3) and (B1).

The preferred units in the first and third diol units (A1) and (A3) and the first and second dicarboxylic acid units (B1) and (B2) are the same as those in the preferred embodiments described above. A more preferred combination of structural units forming the polyester resin is a combination of a structural unit derived from 9,9-bis(hydroxyC _2-4 alkyl)-dinaphthylfluorene such as 9,9-bis(3-hydroxypropyl)-2,7-di(2-naphthyl)fluorene as the first diol unit (A1), a structural unit derived from C _2-4 alkylene glycol such as ethylene glycol as the third diol unit (A3), and a structural unit derived from 9,9-bis(carboxyC _2-4 alkyl)fluorene such as 9,9-bis(2-carboxyethyl)fluorene as the first dicarboxylic acid unit (B1). Particularly preferred combinations include those which further contain a structural unit derived from a naphthalenedicarboxylic acid, such as 2,6-naphthalenedicarboxylic acid, as the second dicarboxylic acid unit (B2) in addition to the above combinations.

When the diol unit (A) contains a diol unit (A2), the diol unit (A2) is preferably a structural unit (A2) in which Z ^2a and Z ^2b are naphthalene rings in the above formula (2), and particularly preferably a structural unit derived from 9,9-bis[hydroxyC _2-4 alkoxy-naphthyl]fluorene such as 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene. When the diol unit (A) contains the diol unit (A2), more preferred combinations of structural units forming the polyester resin are a combination of a structural unit derived from 9,9-bis(hydroxy C _2-4 alkyl)-dinaphthylfluorene such as 9,9-bis(3-hydroxypropyl)-2,7-di(2-naphthyl)fluorene as the first diol unit (A1); a structural unit derived from 9,9-bis[hydroxy C _2-4 alkoxy-naphthyl]fluorene as the second diol unit (A2); a structural unit derived from a C _2-4 alkylene glycol such as ethylene glycol as the third diol unit (A3); and a structural unit derived from 9,9-bis(carboxy C _2-4 alkyl)fluorene such as 9,9-bis(2-carboxyethyl)fluorene as the first dicarboxylic acid unit (B1). Particularly preferred combinations include those which further contain a structural unit derived from a naphthalenedicarboxylic acid, such as 2,6-naphthalenedicarboxylic acid, as the second dicarboxylic acid unit (B2) in addition to the above combinations.

The proportion of the first diol unit (A1) in the polyester resin may be selected from the range of, for example, about 1 to 100 mol% relative to the total diol unit (A), and preferred ranges are 10 to 99 mol%, 30 to 99 mol%, 50 to 99 mol%, 60 to 97 mol%, 70 to 95 mol%, 75 to 92 mol%, and 80 to 90 mol%, in the following stepwise order. If the proportion of the first diol unit (A1) is too low, the refractive index and heat resistance may not be sufficiently improved, and conversely, if it is too high, the birefringence may become large on the negative (minus) side, and the absolute value of the birefringence may not be sufficiently reduced.

When the diol unit (A) contains the diol unit (A1) and the diol unit (A3), the total proportion of the first diol unit (A1) and the third diol unit (A3) may be selected, for example, from a range of about 1 to 100 mol% relative to the total diol unit (A). Preferred ranges are, in the following stepwise order, 10 mol% or more, 30 mol% or more, 50 mol% or more, 70 mol% or more, 90 mol% or more, and substantially 100 mol% is preferred. If the total proportion is too small, the refractive index and moldability may not be sufficiently improved.

When the diol unit (A) contains the diol unit (A1), the diol unit (A2) and the diol unit (A3), the total proportion of the first diol unit (A1), the second diol unit (A2) and the third diol unit (A3) may be selected, for example, from a range of about 1 to 100 mol% relative to the total diol unit (A). Preferred ranges are 10 mol% or more, 30 mol% or more, 50 mol% or more, 70 mol% or more, 90 mol% or more in the following stepwise order, with substantially 100 mol% being preferred. If the total proportion is too small, the refractive index and moldability may not be sufficiently improved.

When the third diol unit (A3) is included, the ratio A1/A3 of the first diol unit (A1) to the third diol unit (A3) may be selected, for example, from the range of about the former/latter (molar ratio) = 1/99 to 99.9/0.1, and the preferred ranges are 50/50 to 99/1, 60/40 to 97/3, 70/30 to 95/5, 75/25 to 92/8, and 80/20 to 90/10 in the following stepwise order. If the ratio of the first diol unit (A1) is too small, the refractive index may not be sufficiently improved, the Tg may be too high, and moldability may be reduced, and the Abbe number may not be reduced. If the ratio of the third diol unit (A3) is too small, the molecular weight may not be sufficiently improved, and moldability may be reduced.

When the second diol unit (A2) [particularly, in the above formula (2), ^Z2a and ^Z2b are naphthalene rings in the structural unit (A2)] are included, the ratio A1/A2 of the first diol unit (A1) to the second diol unit (A2) may be selected, for example, from the range of about 1/99 to 99.9/0.1 (molar ratio) of the former/latter, and the preferred ranges are 1/99 to 70/30, 3/97 to 50/50, 5/95 to 40/60, and 10/90 to 30/70 in the following stepwise manner. If the ratio of the first diol unit (A1) is too small, the refractive index may not be sufficiently improved or the Abbe number may not be reduced. If the ratio of the second diol unit (A2) is too small, the birefringence may not be reduced or the molecular weight may not be sufficiently improved, and moldability may be reduced.

The total proportion of the first dicarboxylic acid unit (B1) and the second dicarboxylic acid unit (B2) may be selected, for example, from a range of about 1 to 100 mol% relative to the total dicarboxylic acid unit (B), with preferred ranges being 10 mol% or more, 30 mol% or more, 50 mol% or more, 70 mol% or more, 90 mol% or more, in the following stepwise order, with substantially 100 mol% being preferred. If the total proportion is too low, it may not be possible to achieve a good balance of properties such as a high refractive index, high moldability, low birefringence, low Abbe number, and heat resistance.

When the first dicarboxylic acid unit (B1) is contained, the proportion of the first dicarboxylic acid unit (B1) may be selected from the range of, for example, about 1 to 100 mol% relative to the total dicarboxylic acid unit (B), and preferred ranges are 50 to 100 mol%, 60 to 95 mol%, 70 to 90 mol%, and 75 to 85 mol% in the following stepwise order. Furthermore, in terms of an excellent balance of high moldability, high refractive index, low Abbe number, and low birefringence, the preferred ranges of the proportion are 40 to 100 mol%, 50 to 90 mol%, and 60 to 80 mol% in the following stepwise order. If the proportion of the first dicarboxylic acid unit (B1) is too small, there is a risk that the birefringence cannot be sufficiently reduced.

When the second dicarboxylic acid unit (B2) is contained, the proportion of the second dicarboxylic acid unit (B2) may be selected, for example, from the range of about 1 to 100 mol% based on the total dicarboxylic acid unit (B), and the preferred ranges are 3 to 90 mol%, 5 to 70 mol%, 10 to 50 mol%, and 20 to 40 mol%, in the following stepwise order.

When both the first and second dicarboxylic acid units (B1) and (B2) are included, the ratio B1/B2 of the first dicarboxylic acid unit (B1) to the second dicarboxylic acid unit (B2) may be selected, for example, from a range of about 1/99 to 99/1 (molar ratio) of the former/latter, and preferred ranges are 50/50 to 99/1, 60/40 to 95/5, 70/30 to 90/10, and 75/25 to 85/15 in the following stepwise order. Furthermore, in terms of an excellent balance of high moldability, high refractive index, low Abbe number, and low birefringence, preferred ranges of the ratio B1/B2 are 40/60 to 95/5, 50/50 to 90/10, and 60/40 to 80/20 in the following stepwise order. If the ratio of the first dicarboxylic acid unit (B1) is too small, there is a risk that the birefringence cannot be sufficiently reduced. If the proportion of the second dicarboxylic acid unit (B2) is too small, the refractive index, Abbe number, and heat resistance may decrease, and the birefringence may not be sufficiently reduced.

The ratio of diol units (A1) to dicarboxylic acid units (B1) in the polyester resin may be selected, for example, from a range of about 1/0.1 to 1/10 (molar ratio) of the former/latter, with preferred ranges being 1/0.2 to 1/8, 1/0.25 to 2, 1/0.3 to 1/1.5, 1/0.5 to 1/1, and 1/0.7 to 1/0.9, in the following stepwise order.

The ratio of diol units (A) to dicarboxylic acid units (B) in the polyester resin is the former/latter (molar ratio) = 1/0.8 to 1/1.2, preferably 1/0.9 to 1/1.1, and more preferably approximately equimolar.

The total proportion of the diol units (A) and the dicarboxylic acid units (B) may be selected, for example, from a range of about 50 to 100 mol% relative to all the constituent units forming the polyester resin, and is preferably 70 mol% or more, more preferably 90 mol% or more, and is particularly preferably substantially 100 mol%.

[Method of producing resin]
The method for producing the resin is not particularly limited except for using the diol component (A) containing the first diol component (A1), and a conventional method can be used depending on the type of resin or other polymerization components (copolymerization components), etc. For example, in the case of a polyester resin, it may be produced by reacting a diol component (A) corresponding to each of the diol units described above with a polymerization component containing a dicarboxylic acid component (B) and/or a carbonate component (C) corresponding to each of the dicarboxylic acid units described above.

Specifically, when the resin contains carbonate units (C), particularly when the resin is a polycarbonate resin, the diol component (A) is reacted (polymerized or condensed) with the carbonate component (C) by, for example, the phosgene method (solvent method) or the ester exchange method (melt method). Of these methods, the ester exchange method is preferred because it does not require a solvent.

In the transesterification method, the ratio of the carbonate diester is, for example, 0.8 to 1.5 moles, preferably 0.9 to 1.2 moles, per mole of the diol component.

The transesterification reaction may be carried out in the presence of a catalyst. Examples of the catalyst include various catalysts used in transesterification reactions, such as nitrogen-containing compounds and metal compounds.

Examples of nitrogen-containing compounds include quaternary ammonium hydroxides (e.g., tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide; trialkyl-aralkylammonium hydroxides such as trimethylbenzylammonium hydroxide); tertiary amines (trialkylamines such as trimethylamine and triethylamine; dimethyl-aralkylamines such as dimethylbenzylamine; triarylamines such as triphenylamine); and the like.

Examples of metals contained in the metal compound include alkali metals such as sodium, alkaline earth metals such as magnesium, calcium, and barium, transition metals such as manganese, zinc, cadmium, lead, cobalt, and titanium, metals in Group 13 of the periodic table such as aluminum, metals in Group 14 of the periodic table such as germanium, and metals in Group 15 of the periodic table such as antimony. Specific metal compounds include, for example, alkoxides of the above metals, organic acid salts such as acetates and propionates, inorganic acid salts such as borates and carbonates, oxides, hydroxides, and the like.

These catalysts can be used alone or in combination of two or more. Among these catalysts, nitrogen-containing compounds such as quaternary ammonium hydroxides are preferred, and among these, tetraalkylammonium hydroxides such as tetramethylammonium hydroxide are preferred. The amount of catalyst used is, for example, 0.01×10 ⁻⁴ to 100×10 ⁻⁴ mol, preferably 0.1×10 ⁻⁴ to 40×10 ⁻⁴ mol, per mol of the diol component.

The reaction may also be carried out in the presence of additives, such as antioxidants, heat stabilizers, and other stabilizers, if necessary.

The reaction can be carried out in an inert gas atmosphere such as nitrogen gas or a rare gas such as helium or argon. The reaction can also be carried out under reduced pressure, for example, at about 1×10 ² to 1×10 ⁴ Pa. The reaction temperature can be selected depending on the polymerization method, and for example, the reaction temperature in the transesterification method is, for example, 150 to 320° C., preferably 200 to 310° C., and more preferably 250 to 300° C. In particular, when diphenyl carbonate is used as the carbonate diester, it is effective to carry out polycondensation while distilling off phenol at high temperature and reduced pressure.

On the other hand, when the dicarboxylic acid unit (B) is contained, particularly when the resin is a polyester resin or a polyester carbonate resin, it can be prepared by, for example, a melt polymerization method such as an ester exchange method or a direct polymerization method, a solution polymerization method, or an interfacial polymerization method, and the melt polymerization method is preferred. The reaction may be carried out in the presence or absence of a solvent depending on the polymerization method.

The ratio of diol component (A) to dicarboxylic acid component (B) used (or the ratio of diol component (A) to dicarboxylic acid component (B)) is, for example, 1/1.2 to 1/0.8, preferably 1/1.1 to 1/0.9, but it does not necessarily have to be in this range. At least one component selected from diol component (A) and dicarboxylic acid component (B) may be used in excess of the planned introduction ratio. For example, a third diol component (A3) such as ethylene glycol that can be distilled from the reaction system may be used in excess of the ratio (or the ratio) introduced into the resin. In addition, when carbonate component (C) is used, the ratio of the total amount of dicarboxylic acid component (B) and carbonate component (C) to diol component (A) used is, for example, 1/1.2 to 1/0.8, preferably 1/1.1 to 1/0.9, former/latter (molar ratio). In addition, taking into consideration volatilization and decomposition during the reaction, the carbonate component (C) may be used in a slight excess over the planned introduction ratio, and the carbonate component (C) may be used in an excess of, for example, 0.1 to 5 mol %, preferably 2 to 3 mol %, over the total amount of dicarboxylic acid units (B) and carbonate units (C) (total amount planned to be introduced into the resin).

The reaction may be carried out in the presence of a catalyst. As the catalyst, a conventional esterification catalyst, for example, a metal catalyst, etc., can be used. As the metal catalyst, for example, a metal compound containing an alkali metal such as sodium; an alkaline earth metal such as magnesium, calcium, barium; a transition metal such as titanium, manganese, cobalt; a metal of Group 12 of the periodic table such as zinc, cadmium; a metal of Group 13 of the periodic table such as aluminum; a metal of Group 14 of the periodic table such as germanium, lead; a metal of Group 15 of the periodic table such as antimony, etc., is used. As the metal compound, for example, an alkoxide; an organic acid salt such as acetate or propionate; an inorganic acid salt such as borate or carbonate; an oxide, etc., or a hydrate thereof may be used. Representative metal compounds include, for example, germanium compounds such as germanium dioxide, germanium hydroxide, germanium oxalate, germanium tetraethoxide, and germanium-n-butoxide; antimony compounds such as antimony trioxide, antimony acetate, and antimony ethylene glycolate; titanium compounds such as tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate (titanium (IV) tetrabutoxide), titanium oxalate, and potassium titanium oxalate; manganese compounds such as manganese acetate tetrahydrate; and calcium compounds such as calcium acetate monohydrate.

These catalysts can be used alone or in combination of two or more. When using a plurality of catalysts, each catalyst can be added according to the progress of the reaction. Among these catalysts, manganese acetate tetrahydrate, calcium acetate monohydrate, germanium dioxide, titanium (IV) tetrabutoxide, etc. are preferred. The amount of the catalyst used is, for example, 0.01×10 ⁻⁴ to 100×10 ⁻⁴ mol, preferably 0.1×10 ⁻⁴ to 40×10 ⁻⁴ mol, per mol of the dicarboxylic acid component (A).

The reaction may be carried out in the presence of a stabilizer such as a heat stabilizer or an antioxidant, if necessary. Usually, a heat stabilizer is often used, and examples of the heat stabilizer include phosphorus compounds such as trimethyl phosphate, triethyl phosphate, triphenyl phosphate, dibutyl phosphate (dibutyl phosphate or dibutyl phosphate), phosphorous acid, trimethyl phosphite, and triethyl phosphite. Of these, dibutyl phosphate is often used. The amount of the heat stabilizer used is, for example, 0.01×10 ⁻⁴ to 100×10 ⁻⁴ moles, preferably 0.1×10 ⁻⁴ to 40×10 ⁻⁴ moles, per mole of the dicarboxylic acid component (A).

The reaction is usually carried out in an atmosphere of an inert gas, for example, nitrogen gas; or a rare gas such as helium or argon. The reaction can also be carried out under reduced pressure, for example, about 1×10 ² to 1×10 ⁴ Pa. Usually, the transesterification reaction is often carried out under an atmosphere of an inert gas such as nitrogen gas, and the polycondensation reaction is often carried out under reduced pressure. The reaction temperature can be selected depending on the polymerization method, and for example, the reaction temperature in the melt polymerization method is 150 to 320° C., preferably 180 to 310° C., and more preferably 200 to 300° C.

[Resin characteristics]
The resin of the present invention contains the first diol unit (A1), and therefore has a high refractive index and high moldability. In addition to the above properties, the resin can also have other properties such as low birefringence, low Abbe number, and high heat resistance in a well-balanced manner.

The glass transition temperature Tg of the resin may be, for example, about 100 to 250°C, preferably 110 to 200°C, more preferably 120 to 180°C, and particularly preferably 130 to 170°C.

When the resin is a polycarbonate resin, the Tg is, for example, 120 to 200°C, preferably 140 to 180°C, more preferably 160 to 175°C, and particularly preferably 165 to 170°C.

When the resin is a polyester carbonate resin, the Tg is, for example, 120 to 190°C, preferably 140 to 175°C, more preferably 150 to 170°C, and particularly preferably 155 to 165°C.

When the resin is a polyester resin, the Tg is, for example, 100 to 170°C, preferably 125 to 160°C, more preferably 130 to 150°C, and particularly preferably 135 to 145°C.

If the Tg is too high, molding such as injection molding must be performed at high temperatures, which not only reduces moldability (fluidity or productivity), but also causes deterioration or discoloration of the resulting molded product due to an increase in molding temperature, and may require a special mold for cooling to suppress distortion in the molded product and prevent a decrease in surface smoothness. On the other hand, if the Tg is too low, the heat resistance may decrease, making the product more susceptible to deterioration or discoloration (or coloration) during molding and/or use, or the resulting molded product may deform in a high-temperature environment, making it impossible to use the resin in applications requiring high heat resistance (or thermal stability), such as optical lenses for vehicles. However, the resin of the present invention has an excellent balance between moldability and heat resistance, as described in the section on the first diol unit (A1), and can be easily adjusted to the above Tg range.

In addition, while prioritizing moldability often results in a lower refractive index, the present invention achieves a good balance between high moldability and a high refractive index. Therefore, the refractive index nD of the resin may be, for example, about 1.67 to 1.74 at a temperature of 20°C and a wavelength of 589 nm, preferably 1.68 to 1.73, more preferably 1.69 to 1.72, and especially 1.7 to 1.71. In addition, for high refractive index applications, the nD of the resin is preferably 1.7 to 1.74, more preferably 1.705 to 1.73, and especially 1.71 to 1.72.

When the resin is a polycarbonate resin, the nD may be, for example, about 1.69 to 1.72, preferably 1.695 to 1.715, and more preferably 1.7 to 1.71. In addition, for high refractive index applications, the nD of the polycarbonate resin is preferably 1.7 to 1.74, more preferably 1.705 to 1.73, and particularly preferably 1.71 to 1.72.

When the resin is a polyester carbonate resin, nD may be, for example, about 1.67 to 1.71, preferably 1.675 to 1.695, and more preferably 1.68 to 1.69.

When the resin is a polyester resin, nD may be, for example, about 1.685 to 1.715, preferably 1.69 to 1.71, and more preferably 1.695 to 1.705.

In the resin of the present invention containing the first diol unit (A1), the Abbe number can be efficiently reduced. Therefore, the Abbe number of the resin at a temperature of 20°C is, for example, 20 or less, preferably 18 or less, more preferably 10 to 17, and even more preferably 12.5 to 16.

When the resin is a polycarbonate resin, the Abbe number is, for example, 17 or less, preferably 12 to 16, more preferably 12.5 to 15, and particularly preferably 13 to 14.

When the resin is a polyester carbonate resin, the Abbe number is, for example, 18 or less, preferably 15 to 17, and more preferably 15.5 to 16.5.

When the resin is a polyester resin, the Abbe number is, for example, 16 or less, preferably 11 to 15, more preferably 12 to 14, and particularly preferably 12.5 to 13.

The resin of the present invention, which exhibits such a low Abbe number, can be effectively used in applications where an even lower Abbe number is required, such as optical components in various cameras, specifically, camera lenses that use a combination of concave and convex lenses. In the optical systems of various cameras, a concave lens with a low Abbe number is used to reduce (or cancel) the chromatic aberration (bleed) that occurs in a convex lens, so the optical systems are usually constructed by combining multiple concave and convex lenses, but the resin of the present invention can fully meet the low Abbe number required for the concave lens.

In addition, since the resin of the present invention contains the first diol unit (A1), birefringence can be efficiently reduced. The birefringence of the resin may be evaluated by the birefringence of a stretched film (3-fold stretched birefringence) obtained by uniaxially stretching a film formed from the resin alone at a stretching temperature of glass transition temperature Tg+10°C, a stretching speed of 25 mm/min, and a stretching ratio of 3 times. The absolute value of the 3-fold stretched birefringence of the stretched film can be selected, for example, from a range of 100×10 ⁻⁴ or less at a measurement temperature of 20°C and a wavelength of 600 nm, and the preferred ranges are 70×10 ⁻⁴ or less, 50×10 ⁻⁴ or less, 25×10 ⁻⁴ or less, 20×10 ⁻⁴ or less, and 10×10 ⁻⁴ or less, stepwise as follows, and more preferably 0 to 5×10 ⁻⁴ .

The weight-average molecular weight Mw of the resin can be measured by gel permeation chromatography (GPC) or the like, and can be selected from a range of, for example, about 10,000 to 1,000,000 in terms of standard polystyrene, preferably 20,000 to 100,000, more preferably 30,000 to 80,000, and particularly preferably 35,000 to 50,000. If the weight-average molecular weight Mw is too low, there is a risk of reduced moldability (productivity) and heat resistance. However, in the present invention, even if the weight-average molecular weight Mw is low, the moldability and other properties are excellent, and are particularly excellent in the case of polyester resins.

When the resin is a polycarbonate resin, the Mw is, for example, 10,000 to 100,000, preferably 20,000 to 80,000, more preferably 30,000 to 60,000, and particularly preferably 40,000 to 50,000.

When the resin is a polyester carbonate resin, the Mw is, for example, 10,000 to 100,000, preferably 20,000 to 80,000, more preferably 30,000 to 60,000, and particularly preferably 40,000 to 50,000.

When the resin is a polyester resin, the Mw is, for example, 10,000 to 100,000, preferably 30,000 to 80,000, more preferably 50,000 to 75,000, and particularly preferably 60,000 to 70,000.

In this specification and claims, the glass transition temperature Tg, refractive index nD, Abbe number, 3-fold stretch birefringence, and weight average molecular weight Mw can be measured by the method described in the examples below.

[Molded body]
The molded article of the present invention may contain at least the resin, and has excellent optical properties such as high refractive index, low birefringence, and low Abbe number, as well as a good balance of various properties such as high moldability and high heat resistance, and can be used as an optical member such as an optical film (or optical sheet) or an optical lens. Such a molded article may contain conventional additives. Examples of the additives include fillers or reinforcing agents, colorants such as dyes and pigments, conductive agents, flame retardants, plasticizers, lubricants, release agents, antistatic agents, dispersants, flow control agents, leveling agents, defoamers, surface modifiers, hydrolysis inhibitors, carbon materials, stabilizers, and stress reducing agents. Examples of the stabilizers include antioxidants, ultraviolet absorbers, and heat stabilizers. Examples of the stress reducing agents include silicone oils, silicone rubbers, various plastic powders, and various engineering plastic powders. These additives may be used alone or in combination of two or more.

Molded bodies can be manufactured using, for example, injection molding, injection compression molding, extrusion molding, transfer molding, blow molding, pressure molding, casting molding, etc.

The shape of the molded body is not particularly limited, and examples include one-dimensional structures such as lines, fibers (or fibres) and threads, two-dimensional structures such as films, sheets and plates, and three-dimensional structures such as concave or convex lenses, rods and hollow (tubular) shapes.

In particular, the resin of the present invention is useful for forming optical films because it has various excellent optical properties. Therefore, the present invention also includes films (optical films or optical sheets) formed from the resin.

The average thickness of such a film can be selected from a range of about 1 to 1000 μm depending on the application, for example, 1 to 200 μm, preferably 5 to 150 μm, and more preferably 10 to 120 μm.

Such films (optical films) can be produced by forming (or molding) the resin using a conventional film-forming method, such as a casting method (solvent casting method), melt extrusion method, or calendar method.

The film may be a stretched film. The film of the present invention can maintain low birefringence even if it is a stretched film. Such a stretched film may be either a uniaxially stretched film or a biaxially stretched film.

In the case of uniaxial or biaxial stretching, the stretching ratio is, for example, 1.1 to 10 times, preferably 1.2 to 5 times, and more preferably 1.5 to 3 times, in each direction. In the case of biaxial stretching, it may be equal stretching, for example, stretching about 1.5 to 5 times in both the longitudinal and transverse directions, or it may be uneven stretching, for example, stretching about 1.1 to 4 times in the longitudinal direction and about 2 to 6 times in the transverse direction. In the case of uniaxial stretching, it may be longitudinal stretching, for example, stretching about 2.5 to 8 times in the longitudinal direction, and transverse stretching, for example, stretching about 1.2 to 5 times in the transverse direction.

The average thickness of the stretched film is, for example, 1 to 150 μm, preferably 3 to 120 μm, and more preferably 5 to 100 μm.

Such a stretched film can be obtained by stretching the film (or unstretched film) after film formation. There are no particular limitations on the stretching method, and in the case of uniaxial stretching, either a wet stretching method or a dry stretching method may be used, and in the case of biaxial stretching, either a tenter method (flat method) or a tube method may be used, although the tenter method, which has excellent uniformity in the stretched thickness, is preferred.

The molded article may also be joined or adhered to another substrate, and the type or material of the substrate is not particularly limited, and may be, for example, a substrate having a one-dimensional, two-dimensional, or three-dimensional shape formed from a resin material, a ceramic material, a metal material, or the like. For example, if the molded article is in the form of a film, it may be combined with a substrate having a two-dimensional shape such as a film to form a laminate or laminate film.

Typical examples of the substrate having a two-dimensional shape include ceramic substrates such as glass substrates, resin films, etc., with transparent substrates being preferred. Examples of the resin forming the resin film include polyolefin resins such as linear olefin resins and cyclic olefin resins (or cycloolefin resins); (meth)acrylic resins; styrene resins; polyester resins such as polyalkylene arylate resins, polyarylate resins, and polycarbonate resins; and polyamide resins. In particular, the substrate may be used by laminating it with a resin film formed from a cycloolefin resin, polyamide resin, or the like.

The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. Details of the evaluation method are shown below.

[Evaluation method]
(HPLC)
The HPLC purity [area %] of the sample was calculated by high performance (or fast) liquid chromatography (HPLC) based on the following measurement equipment and conditions.

Equipment: Hitachi High-Technologies Corporation "L-2000"
Column: "Cadenza CL-C18 (3 μm) 3.0 × 250 mm" manufactured by Imtakt Co., Ltd.
Guard column: "GCCD0S" manufactured by Imtakt Co., Ltd.
Detector: L-2420 UV-VIS detector ( _D2 lamp, 254 nm)
Mobile phase: acetonitrile/distilled water (volume ratio) = 90/10 (Kanto Chemical Co., Ltd., LC grade)
Flow rate: 0.5mL/min

(FD-MS)
Mass spectrometry (MS) was performed using the following measuring device and conditions.

Equipment used: “JMS-T200GC” manufactured by JEOL Ltd.
Ionization method: FD (field desorption)
Emitter: Carbon Emitter current: 0-50mA (25mA/min).

(Melting Point)
Measurement was performed using a differential scanning calorimeter ("EXSTAR DSC6200" manufactured by SII NanoTechnology, Inc.) under conditions of a nitrogen atmosphere, a measurement temperature of 30 to 220° C., and a temperature rise rate of 10° C./min. From the obtained DSC chart (DSC curve), the peak top temperature of the endothermic peak due to melting was determined as the melting point.

(5% mass loss temperature)
Using a thermogravimetry-differential thermal analyzer (TG-DTA) ("TG/DTA6200" manufactured by SII NanoTechnology Inc.), the temperature at which the mass of the sample decreased by 5% by mass was measured under conditions of a nitrogen atmosphere and a heating rate of 10° C./min.

( ^1H -NMR)
The sample was dissolved in a deuterated solvent (CDCl ₃ or DMSO-d ₆ ) containing tetramethylsilane as an internal standard substance, and the ¹ H-NMR spectrum was measured using a nuclear magnetic resonance apparatus ("AVANCE III HD" manufactured by BRUKER).

In addition, in the case of preparing a resin (polymer), the integral values of the peaks derived from each monomer used in the polymerization were calculated for the obtained spectrum, and the proportion of each monomer component (structural unit) introduced into the resin (polymer composition ratio) was calculated.

(Glass transition temperature Tg)
The measurement was performed using a differential scanning calorimeter ("EXSTAR6000 DSC6220 ASD-2" manufactured by SII NanoTechnology Inc.) in a nitrogen gas atmosphere at a temperature increase rate of 10° C./min.

(molecular weight)
The sample was dissolved in chloroform, and the weight average molecular weight Mw in terms of standard polystyrene was determined using gel permeation chromatography ("HLC-8320GPC" manufactured by Tosoh Corporation).

(Refractive index nD)
The refractive indexes of DNFDP-m and DNFPO prepared in Example 1 were measured at a temperature of 25° C. and a wavelength of 589 nm (D line) using a refractometer (DR-M2 (circulating thermostatic bath 60-C3) manufactured by Atago Co., Ltd.). The refractive index was calculated by extrapolating the concentration to 100% by mass on a calibration curve (approximation line) prepared by dissolving a sample in dimethyl sulfoxide to prepare solutions with concentrations of 6.05% by mass, 10.94% by mass, and 30.30% by mass and measuring the refractive index of the obtained solutions.

The refractive index of the resin sample was measured as follows. The sample was heat pressed at 200-240°C to form a film with a thickness of 200-300 μm. This film was cut into strips measuring 20-30 mm in length and 10 mm in width to obtain test pieces. The refractive index nD of the obtained test pieces at 589 nm (D line) was measured using a multi-wavelength Abbe refractometer (DR-M4 (circulating thermostatic bath 60-C3) manufactured by Atago Co., Ltd.) at a measurement temperature of 20°C and diiodomethane as the contact liquid.

(Abbe number)
Using the test piece for measuring the refractive index nD at 589 nm (D line), the refractive indexes nF and nC were measured in the same manner as for the refractive index nD, except that the measurement wavelengths were changed to 486 nm (F line) and 656 nm (C line). The Abbe number was calculated from the refractive indexes nF, nD, and nC at the respective wavelengths by the following formula.

(Abbe number) = (nD-1)/(nF-nC).

(Birefringence (three-times stretched birefringence))
The sample was hot pressed at 200 to 240 ° C. to form a film having a thickness of 200 to 600 μm. This film was cut into a rectangular shape of 10 mm wide x 50 mm long, and uniaxially stretched in the longitudinal direction at a temperature of glass transition temperature Tg + 10 ° C. at 25 mm / min so that the stretch ratio was 3 times (so that the longitudinal 50 mm became 150 mm) to obtain a test piece. The retardation of the obtained test piece was measured by the parallel Nicol rotation method using a retardation film / optical material inspection device (manufactured by Otsuka Electronics Co., Ltd. "RETS-100") under conditions of a measurement temperature of 20 ° C. and a measurement wavelength of 600 nm, and the value was divided by the thickness of the measurement site to calculate the birefringence (or 3-fold stretched birefringence).

[Resin raw materials]
(Diol component)
DNFPO: 2,7-di(2-naphthyl)-9,9-fluorenedipropanol [or 2,7-di(2-naphthyl)-9,9-bis(3-hydroxypropyl)fluorene], synthesized according to Example 1 described later. BNEF: 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene, synthesized according to Synthesis Example 1 described in JP-A-2018-59074. BPEF: 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, manufactured by Osaka Gas Chemicals Co., Ltd. BINOL-2EO: 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthyl, synthesized according to Synthesis Example 2 described in JP-A-2018-59074. EG: Ethylene glycol (carbonate bond forming component)
DPC: Diphenyl carbonate (dicarboxylic acid component)
FDP-m: 9,9-bis(2-methoxycarbonylethyl)fluorene [or dimethyl ester of 9,9-bis(2-carboxyethyl)fluorene], synthesized in the same manner as in Example 1 of JP2005-89422A, except that methyl acrylate [37.9 g (0.44 mol)] was used instead of t-butyl acrylate. DMT: dimethyl terephthalate. DMN: 2,6-bis(methoxycarbonyl)naphthalene.

[Example 1]
(Preparation of DBrFDP-m)
2,7-Dibromo-9,9-bis(2-methoxycarbonylethyl)fluorene (DBrFDP-m) was synthesized in the same manner as in Example 1 described in JP 2005-89422 A, except that 37.9 g (0.44 mol) of methyl acrylate was used instead of t-butyl acrylate and 54.7 g (0.17 mol) of 2,7-dibromo-9H-fluorene was used instead of fluorene.

(Preparation of DNFDP-m)
In a reactor, 192.3 g (0.39 mol) of DBrFDP-m, 200 g (1.2 mol) of 2-naphthylboronic acid, 4.3 L of dimethoxyethane, and 1 L of 2M aqueous sodium carbonate solution were charged, and 22.4 g (19.4 mmol) of tetrakis(triphenylphosphine)palladium(0) [or Pd(PPh ₃ ) ₄ ] was added under a nitrogen stream, and the mixture was heated under reflux at an internal temperature of 71 to 78° C. for 5 hours to cause a reaction. After cooling to room temperature, 2.0 L of toluene and 500 mL of ion-exchanged water were added, and the mixture was washed by extracting the mixture by separation 5 times. The organic layer changed from deep orange to brown. Insoluble matter was filtered and concentrated to obtain 305 g of brown crude crystals. The obtained crude crystals were dissolved by heating in a mixture of 1.5 kg of ethyl acetate and 300 g of isopropyl alcohol (IPA), cooled to 10°C or less with ice water, and stirred for 1 hour to precipitate crystals. The precipitated crystals were filtered and dried under reduced pressure to obtain 130 g of gray-brown crystals. The obtained gray-brown crystals were purified by column chromatography (silica gel carrier, developing solvent chloroform:ethyl acetate (volume ratio) = 4:1), recrystallized with methanol, and dried under reduced pressure to obtain 116 g of 9,9-bis(2-methoxycarbonylethyl)-2,7-di(2-naphthyl)fluorene (DNFDP-m) represented by the following formula (white crystals, yield 54.9%, HPLC purity 99.4 area%). The results of ¹ H-NMR and FD-MS are shown below.

¹ H-NMR (CDCl ₃ , 300 MHz): δ (ppm) 1.7 (t, 4H), 2.6 (t, 4H), 3.4 (s, 6H), 7.5 (m, 4H), 7.7-8.0 (m, 14H), 8.1 (s, 2H)

FD-MS: m/z 590 (M+).

The refractive index nD of DNFDP-m was 1.845, the melting point was 191°C, and the 5% mass loss temperature was 390°C.

(Preparation of DNFPO)
Under a nitrogen atmosphere, DNFDP-m (1.2 kg, 2.03 mol) and tetrahydrofuran (THF, 9.78 kg) were added to a 20 L separable flask, and the flask was cooled to 10 ° C. or less in an ice-water bath. Sodium borohydride (230 g, 6.08 mol) was gradually added to the resulting solution over 13 minutes, and then boron trifluoride-ether complex (856 g, 6.09 mol) was added dropwise over 45 minutes, and the mixture was then heated to room temperature and stirred for 4 hours. The mixture was cooled in an ice-water bath, and then acetone (1.0 kg, 17.2 mol) was added dropwise over 1 hour, after which the solvent was removed by vacuum concentration. Then, 12 kg of chloroform, 1.0 kg of ion-exchanged water, and 3.0 kg of ice were added, and the aqueous layer was removed. Furthermore, 4.0 kg of ion-exchanged water was added, and the aqueous layer was removed twice (washed twice with ion-exchanged water) to remove only the organic layer. The resulting solution was concentrated under reduced pressure to obtain 1.0 kg of DNFPO represented by the following formula, i.e., 2,7-di(2-naphthyl)-9,9-(3-hydroxypropyl)fluorene (white solid, yield 92.1%, HPLC purity 99% by area). The results of ¹ H-NMR and FD-MS are shown below.

¹ H-NMR (DMSO-d ₆ , 300 MHz): δ (ppm) 0.9 (m, 4H)
, 2.2 (m, 4H), 3.2 (t, 4H), 4.2 (t, 2H), 7.5-8.4 (m, 20H).

FD-MS: m/z 535 (M+).

The refractive index nD of DNFPO was 1.756, the melting points were 186°C and 220°C, and the 5% mass loss temperature was 392°C.

[Polycarbonate resin]
[Example 2]
0.50 mol of DNFPO and 0.50 mol of BPEF were added as diol components, 1.05 mol of DPC as a carbonate component (carbonate bond forming component), and 2×10 ⁻⁴ mol of tetramethylammonium hydroxide as an ester exchange catalyst, and gradually heated and melted under stirring in a nitrogen gas atmosphere. After heating to 250° C., the pressure was reduced stepwise to 10,000 Pa. Phenol was removed while gradually heating and reducing the pressure until it reached 270° C. and 130 Pa or less. After reaching a predetermined stirring torque, the contents were removed from the reactor to obtain a polycarbonate resin. 50 mol% of the diol units constituting the obtained polycarbonate resin were derived from DNFPO and 50 mol% were derived from BPEF.

[Example 3]
A polycarbonate resin was obtained in the same manner as in Example 2, except that 0.30 mol of DNFPO and 0.70 mol of BPEF were used as the diol components, and 1.05 mol of DPC was used as the carbonate component. 30 mol % of the diol units constituting the obtained polycarbonate resin were derived from DNFPO, and 70 mol % were derived from BPEF.

[Comparative Example 1]
A polycarbonate resin was obtained in the same manner as in Example 2, except that 1.00 mol of BPEF was used as the diol component and 1.05 mol of DPC was used as the carbonate component. 100 mol % of the diol units constituting the obtained polycarbonate resin were derived from BPEF.

[Example 4]
A polycarbonate resin was obtained in the same manner as in Example 2, except that 0.50 mol of DNFPO and 0.50 mol of BNEF were used as the diol components, and 1.05 mol of DPC was used as the carbonate component. 50 mol % of the diol units constituting the obtained polycarbonate resin were derived from DNFPO and 50 mol % were derived from BNEF.

[Example 5]
A polycarbonate resin was obtained in the same manner as in Example 2, except that 0.60 mol of DNFPO and 0.40 mol of BNEF were used as the diol components, and 1.05 mol of DPC was used as the carbonate component. 60 mol % of the diol units constituting the obtained polycarbonate resin were derived from DNFPO and 40 mol % were derived from BNEF.

[Comparative Example 2]
A polycarbonate resin was obtained in the same manner as in Example 2, except that 1.00 mol of BNEF was used as the diol component and 1.05 mol of DPC was used as the carbonate component. 100 mol % of the diol units constituting the obtained polycarbonate resin were derived from BNEF.

The charge ratios for the examples and comparative examples in which polycarbonate resin was prepared are shown in Table 1, and the evaluation results are shown in Table 2.

As is clear from Table 2, the polycarbonate resins obtained in the Examples were able to significantly improve the refractive index without excessively increasing the Tg compared to the corresponding Comparative Examples, and were able to achieve both high moldability and refractive index. Note that even an increase in the refractive index of about 0.01 is considered to be advantageous, and this can be considered a remarkable effect. Furthermore, in the Examples, the Abbe number was significantly reduced compared to the Comparative Examples, and the absolute value of the 3-fold stretch birefringence was reduced or kept low. Among these, Examples 4 to 5, and especially Example 5, were able to achieve a good balance of high moldability, high refractive index, low Abbe number, and low birefringence at a higher level.

[Polyester carbonate resin]
[Example 6]
As diol components, DNFPO 0.30 mol and BNEF 0.30 mol, DPC 0.21 mol as carbonate component, FDP-m 0.40 mol as dicarboxylic acid component, titanium (IV) tetrabutoxide (2.7 mg (8 μmol)) as a catalyst for transesterification and polycondensation reaction was charged, and after heating and stirring at 210 ° C. for 1 hour under a nitrogen gas atmosphere, the mixture was gradually heated to 240 ° C. and stirred to carry out transesterification. After removing the alcohol component and phenol component generated by the transesterification reaction, the temperature was gradually raised to 290 ° C. and 130 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached. After the reaction was completed, the contents were removed from the reactor to obtain a polyester carbonate resin. Of the diol units constituting the obtained polyester carbonate resin, 50 mol % were derived from DNFPO and 50 mol % were derived from BNEF, and of the carbonate units and dicarboxylic acid units constituting the resin, 33 mol % were derived from DPC and 67 mol % were derived from FDP-m.

[Example 7]
A polyester carbonate resin was obtained in the same manner as in Example 6, except that 0.20 mol of DNFPO and 0.40 mol of BNEF were used as the diol components, 0.21 mol of DPC as the carbonate component, and 0.40 mol of FDP-m as the dicarboxylic acid component were used. 33 mol% of the diol units constituting the obtained polyester carbonate resin were derived from DNFPO and 67 mol% were derived from BNEF, and 33 mol% of the carbonate units and dicarboxylic acid units constituting the resin were derived from DPC and 67 mol% were derived from FDP-m.

[Comparative Example 3]
A polyester carbonate resin was obtained in the same manner as in Example 6, except that 0.60 mol of BNEF was used as the diol component, 0.21 mol of DPC was used as the carbonate component, and 0.40 mol of FDP-m was used as the dicarboxylic acid component. 100 mol% of the diol units constituting the obtained polyester carbonate resin were derived from BNEF, and 33 mol% of the carbonate units and dicarboxylic acid units constituting the resin were derived from DPC and 67 mol% were derived from FDP-m.

The feed ratios for the examples and comparative examples in which polyester carbonate resins were prepared are shown in Table 3, and the evaluation results are shown in Table 4.

As is clear from Table 4, the polyester carbonate resin obtained in the Examples was able to greatly improve the refractive index without excessively increasing the Tg, and was able to achieve both high moldability and refractive index, compared to the corresponding Comparative Examples. Furthermore, in the Examples, the Abbe number was also greatly reduced, and the absolute value of the birefringence after 3-fold stretching was also reduced, compared to the Comparative Examples. In particular, in Example 7, high moldability, high refractive index, low Abbe number, and low birefringence were achieved in a well-balanced manner at a higher level.

[Polyester resin]
[Example 8]
As diol components, 0.75 mol of DNFPO and 2.25 mol of EG, as dicarboxylic acid components, 1 mol of FDP-m, as catalysts for transesterification and polycondensation reactions, titanium (IV) tetrabutoxide (1.4 mg (4 μmol)), as a heat stabilizer, dibutyl phosphate (8.4 mg (40 μmol)) were charged, and the mixture was gradually heated to 245 ° C. under a nitrogen gas atmosphere, stirred, and transesterification reaction was carried out. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually raised to 280 ° C. and 130 Pa, the pressure was reduced, and while removing EG, a polycondensation reaction was carried out until a predetermined stirring torque was reached. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin. 75 mol% of the diol units constituting the obtained polyester resin were derived from DNFPO, 25 mol% were derived from EG, and 100 mol% of the dicarboxylic acid units constituting the resin were derived from FDP-m.

[Comparative Example 4]
A polyester resin was obtained in the same manner as in Example 8, except that 0.75 mol of BNEF and 2.25 mol of EG were used as the diol components, and 1 mol of FDP-m was used as the dicarboxylic acid component. 75 mol% of the diol units constituting the obtained polyester resin were derived from BNEF, 25 mol% were derived from EG, and 100 mol% of the dicarboxylic acid units constituting the resin were derived from FDP-m.

[Comparative Example 5]
A polyester resin was obtained in the same manner as in Example 8, except that 0.80 mol of BNEF and 2.20 mol of EG were used as the diol components, and 1 mol of DMN was used as the dicarboxylic acid component. 80 mol % of the diol units constituting the obtained polyester resin were derived from BNEF, 20 mol % were derived from EG, and 100 mol % of the dicarboxylic acid units constituting the resin were derived from DMN.

[Example 9]
A polyester resin was obtained in the same manner as in Example 8, except that 0.85 mol of DNFPO and 2.15 mol of EG were used as the diol components, and 0.70 mol of FDP-m and 0.30 mol of DMN were used as the dicarboxylic acid components. 85 mol% of the diol units constituting the obtained polyester resin were derived from DNFPO and 15 mol% were derived from EG, and 70 mol% of the dicarboxylic acid units constituting the resin were derived from FDP-m and 30 mol% were derived from DMN.

[Comparative Example 6]
A polyester resin was obtained in the same manner as in Example 8, except that 0.85 mol of BPEF and 2.15 mol of EG were used as the diol components, and 0.70 mol of FDP-m and 0.30 mol of DMN were used as the dicarboxylic acid components. 85 mol% of the diol units constituting the obtained polyester resin were derived from BPEF and 15 mol% were derived from EG, and 70 mol% of the dicarboxylic acid units constituting the resin were derived from FDP-m and 30 mol% were derived from DMN.

[Example 10]
A polyester resin was obtained in the same manner as in Example 8, except that 0.7 mol of DNFPO and 2.3 mol of EG were used as the diol components, and 1 mol of DMT was used as the dicarboxylic acid component. 70 mol % of the diol units constituting the obtained polyester resin were derived from DNFPO, 30 mol % were derived from EG, and 100 mol % of the dicarboxylic acid units constituting the resin were derived from DMT.

[Comparative Example 7]
A polyester resin was obtained in the same manner as in Example 8, except that 0.7 mol of BPEF and 2.3 mol of EG were used as the diol components, and 1 mol of DMT was used as the dicarboxylic acid component. 70 mol % of the diol units constituting the obtained polyester resin were derived from BPEF and 30 mol % were derived from EG, and 100 mol % of the dicarboxylic acid units constituting the resin were derived from DMT.

[Example 11]
A polyester resin was obtained in the same manner as in Example 8, except that 0.4 mol of DNFPO, 0.4 mol of BNEF, and 2.2 mol of EG were used as the diol components, and 0.50 mol of FDP-m and 0.50 mol of DMN were used as the dicarboxylic acid components. 40 mol% of the diol units constituting the obtained polyester resin were derived from DNFPO, 40 mol% were derived from BNEF, and 20 mol% were derived from EG, and 50 mol% of the dicarboxylic acid units constituting the resin were derived from FDP-m and 50 mol% were derived from DMN.

[Comparative Example 8]
A polyester resin was obtained in the same manner as in Example 8, except that 0.4 mol of BNEF, 0.4 mol of BINOL-2EO, and 2.2 mol of EG were used as the diol components, and 0.50 mol of FDP-m and 0.50 mol of DMN were used as the dicarboxylic acid components. 40 mol% of the diol units constituting the obtained polyester resin were derived from BNEF, 40 mol% were derived from BINOL-2EO, and 20 mol% were derived from EG, and 50 mol% of the dicarboxylic acid units constituting the resin were derived from FDP-m and 50 mol% were derived from DMN.

[Example 12]
A polyester resin was obtained in the same manner as in Example 8, except that 0.15 mol of DNFPO, 0.6 mol of BNEF, and 2.25 mol of EG were used as the diol components, and 1 mol of FDP-m was used as the dicarboxylic acid component. 15 mol% of the diol units constituting the obtained polyester resin were derived from DNFPO, 60 mol% were derived from BNEF, and 25 mol% were derived from EG, and 100 mol% of the dicarboxylic acid units constituting the resin were derived from FDP-m.

The feed ratios for the polyester resins prepared in the examples and comparative examples are shown in Table 5, and the evaluation results are shown in Table 6.

As is clear from Table 6, the polyester resins obtained in the Examples were able to significantly improve the refractive index without excessively increasing the Tg compared to the corresponding Comparative Examples, and were able to achieve both high moldability and refractive index. Furthermore, in the Examples, the Abbe number was significantly reduced compared to the Comparative Examples, and the absolute value of the 3-fold stretched birefringence was reduced or kept low. In particular, in Example 9, high moldability, high refractive index, low Abbe number, and low birefringence were achieved at a higher level in a well-balanced manner.

In a comparison between Example 11 and Comparative Example 8, a high refractive index was achieved by using DNFPO instead of BINOL-2EO. In Example 12, by using BNEF as the second diol unit (A2), a high refractive index and low birefringence were achieved, although the refractive index was slightly lower than in Example 9.

In addition, the polyester resins of the examples are easier to handle than polycarbonate resins and polyester carbonate resins, likely due to their better mechanical properties, such as flexibility (toughness), and when molded into lenses, films, etc., they have particularly high moldability (or productivity) compared to polycarbonate resins and polyester carbonate resins.

The diol compound of the present invention can be used as a resin raw material (or monomer) for forming a resin that exhibits excellent optical properties such as a high refractive index and high moldability. Therefore, the resin obtained by using the diol compound of the present invention as a raw material can be used for various purposes by taking advantage of the above properties, such as coating agents or coating films, specifically, paints, inks, protective films for electronic devices and liquid crystal components, etc.; adhesives, pressure sensitive adhesives; resin fillers; electric and electronic materials or electric and electronic parts (electric and electronic devices), specifically, antistatic agents, carrier transport agents, light emitting bodies, organic photoreceptors, thermal recording materials, photochromic materials, hologram recording materials, charging trays, conductive sheets, optical disks, inkjet printers, digital paper, color filters, organic EL elements, organic semiconductor lasers, dye-sensitized solar cells, sensors, EMI shielding films, etc.; mechanical materials or mechanical parts (equipment), specifically, automotive materials or parts, aerospace-related materials or parts, sliding members, etc.

The resin of the present invention can be particularly effectively used as an optical component. Representative optical components include optical films (optical sheets) such as films for liquid crystals and films for organic electroluminescence (EL); optical lenses such as lenses for glasses and lenses for cameras; prisms, holograms, optical fibers, etc.

Examples of optical films include polarizing films, polarizing elements and polarizing plate protective films that constitute polarizing films, diffusion plates (films), prism sheets, light guide plates, brightness enhancing films, near-infrared absorbing films, reflective films, anti-reflection (AR) films, reflection reducing (LR) films, anti-glare (AG) films, transparent conductive (ITO) films, anisotropic conductive films (ACF), electromagnetic shielding (EMI) films, films for electrode substrates, films for color filter substrates, barrier films, color filter layers, black matrix layers, adhesive layers or release layers between optical films, etc. These optical films can be effectively used as optical films for displays such as liquid crystal displays (LCDs), organic electroluminescent displays (OLEDs), plasma displays (PDPs), field emission displays (FEDs), and electronic paper, and specific devices or apparatuses include televisions; personal computers (PCs) such as desktop PCs, notebook PCs, and tablet PCs; smartphones, mobile phones; car navigation systems; and devices or apparatuses equipped with flat panel displays (FPDs) such as touch panels.

Examples of optical lenses include eyeglass lenses, contact lenses, camera lenses, VTR zoom lenses, pickup lenses, Fresnel lenses, solar concentrating lenses, objective lenses, and rod lens arrays. In particular, optical lenses are suitable for use in lenses that require a low Abbe number, such as camera lenses. Typical devices or equipment that can be equipped with such optical lenses include small or mobile devices with camera functions, such as smartphones, mobile phones, and digital cameras; and in-vehicle cameras, such as drive recorders and backup cameras (rear cameras).

Claims (19)

The following formula (1)

[In the formula, Y ^1a and Y ^1b each independently represent the following formula (Y1):

(wherein ^Z1 represents an arene ring;
^R1 represents a substituent, and m1 represents an integer of 0 or 1 or more.
k1a and k1b each independently represent an integer of 0 to 4, and at least one of k1a and k1b is 1 or more;
R ^2a and R ^2b each independently represent a substituent; m2a and m2b each independently represent an integer of 0 to 4;
k1a + m2a and k1b + m2b are each independently 4 or less;
^Y2a and ^Y2b each independently represent the following formula (Y2):

(In the formula, ^A1 and ^A2 each independently represent a linear or branched alkylene group, and n2 represents 0 or an integer of 1 or more.)
It represents a monovalent group represented by the following formula:
A method for producing a diol compound represented by the following formula:
The following formula (I)

[In the formula, Y3a ^and Y3b ^each independently represent the following formula (Y3):

(In the formula, A3 ^represents a linear or branched alkylene group,
R3 represents a hydrogen atom or an alkyl group ^.
represents a monovalent group represented by
Y ^1a and Y ^1b , k1a and k1b, R ^2a and R ^2b , and m2a and m2b are the same as those in formula (1).
A method for producing a diol compound, comprising a reduction step of reducing a compound represented by the following formula : In the formula (1), Z ¹ is a C _6-12 arene ring, k1a and k2b are integers of 1 to 2,
A ¹ is a linear or branched C _1-6 alkylene group;
The process according to claim 1, wherein ^A2 is a linear or branched _C2-4 alkylene group, and n2 is 0 or an integer of 1 to 10. In the formula (1), ^Z1 is a benzene ring or a naphthalene ring, k1a and k2b are each 1;
A ¹ is a linear or branched C _1-4 alkylene group;
The method according to claim 1 or 2, wherein n2 is 0. As the diol unit (A), a diol unit represented by the following formula (1P)

[In the formula, Y ^2c and Y ^2d each independently represent the following formula (Y2c):

(In the formula, A ¹ represents a trimethylene group, n2 represents 0 , A ² is the same as in formula (1) of claim 1, ^{and A 1} is bonded to the 9-position of the fluorene ring.)
represents a divalent group represented by
Y ^1a and Y ^1b , k1a and k1b, R ^2a and R ^2b , and m2a and m2b are the same as those in formula (1) of claim 1.
and a first diol unit (A1) represented by the following formula (2):

(In the formula, Z ^2a and Z ^2b each independently represent an arene ring,
R4 represents a substituent; m4 represents an integer of 0 to 8 ^;
R5a and R5b ^each independently represent a substituent; m5a and m5b each independently represent an integer of 0 or 1 or more ^;
A4a and ^A4b each independently represent a linear or branched alkylene group, ^and n4a and n4b each independently represent an integer of 0 or 1 or more.
and a second diol unit (A2) represented by the following formula: In the formula (2), Z ^2a and Z ^2b C _6-10 is an arene ring,
R ^5a and R ^5b is a hydrocarbon group, m5a and m5b are integers of 0 to 2,
A ^4a and A ^4b is linear or branched C _2-6 5. The polycarbonate resin according to claim 4, wherein n4a and n4b are each an alkylene group, and n4a and n4b are each an integer of 0 to 3. 6. The polycarbonate resin according to claim 4 , wherein the proportion of the first diol unit (A1) represented by the formula (1P) is 5 to 100 mol % based on the total diol units (A). The polycarbonate resin according to any one of claims 4 to 6, wherein a ratio of the first diol unit (A1) to the second diol unit (A2) is the former/the latter (molar ratio) = 20/80 to 80/20. As the diol unit (A), a diol unit represented by the following formula (1P)

[In the formula, Y ^2c and Y ^2d each independently represent the following formula (Y2c):

(In the formula, A ¹ , A ² and n2 are the same as those in the formula (1) of claim 1, and A ¹ is bonded to the 9-position of the fluorene ring.)
represents a divalent group represented by
Y ^1a and Y ^1b , k1a and k1b, R ^2a and R ^2b , and m2a and m2b are the same as those in formula (1) of claim 1.
The polyester carbonate resin contains a first diol unit (A1) represented by the following formula : 9. The polyester carbonate resin according to claim 8, wherein the proportion of the first diol unit (A1) represented by the formula (1P) is 5 to 100 mol % based on the total diol units (A). The polyester carbonate resin according to claim 8 or 9 , wherein the diol unit (A) further comprises the second diol unit (A2) according to claim 4 or 5 . As the dicarboxylic acid unit (B),

(In the formula, ^R6 represents a substituent, m6 represents an integer of 0 to 8,
A ^6a and A ^6b each independently represent a linear or branched alkylene group. The polyester carbonate resin according to any one of claims 8 to 10, further comprising a first dicarboxylic acid unit (B1) represented by the following formula : the diol unit (A) further contains the second diol unit (A2) according to claim 4 or 5, and the ratio of the first diol unit (A1) to the second diol unit (A2) (molar ratio) is 10/90 to 50/50;
the ratio of the dicarboxylic acid unit (B) is 0.5 to 0.85 mol per 1 mol of the diol unit (A),
12. The polyester carbonate resin according to claim 11 , wherein the proportion of the first dicarboxylic acid units (B1) is 50 to 100 mol % based on the total of the dicarboxylic acid units (B). As the diol unit (A), a diol unit represented by the following formula (1P)

[In the formula, Y ^2c and Y ^2d each independently represent the following formula (Y2c):

(In the formula, A ¹ , A ² and n2 are the same as those in the formula (1) of claim 1, and A ¹ is bonded to the 9-position of the fluorene ring.)
represents a divalent group represented by
Y ^1a and Y ^1b , k1a and k1b, R ^2a and R ^2b , and m2a and m2b are the same as those in formula (1) of claim 1.
and as the dicarboxylic acid unit (B), the first dicarboxylic acid unit (B1) according to claim 11 . The diol unit (A) is represented by the following formula (3):

(In the formula, ^A5 represents a linear or branched alkylene group, and n5 represents an integer of 1 or more.)
The polyester resin according to claim 13 , further comprising a third diol unit (A3) represented by: The dicarboxylic acid unit (B) is represented by the following formula (5):

(Wherein, ^Z3 represents an arene ring;
^R7 represents a substituent, and m7 represents an integer of 0 or 1 or more.
The polyester resin according to claim 13 or 14 , further comprising a second dicarboxylic acid unit (B2) represented by the following formula: The diol unit (A) further comprises a third diol unit (A3) according to claim 14,
a molar ratio of the first diol unit (A1) to the third diol unit (A3) is the former/the latter=70/30 to 95/5,
the ratio of the first dicarboxylic acid unit (B1) is 0.3 to 1.5 moles per mole of the first diol unit (A1);
The dicarboxylic acid unit (B) further comprises a second dicarboxylic acid unit (B2) according to claim 15,
The polyester resin according to any one of claims 13 to 15, wherein a ratio of the first dicarboxylic acid unit (B1) to the second dicarboxylic acid unit (B2) is the former/the latter (molar ratio) = 50/50 to 90/10. A molded article comprising the polycarbonate resin according to any one of claims 4 to 7 , the polyester carbonate resin according to any one of claims 8 to 12, or the polyester resin according to any one of claims 13 to 16 . The molded article according to claim 17 , which is an optical member. The molded article according to claim 17 or 18 , which is an optical film or an optical lens.