JP7656439B2 - Thermoplastic resin having a binaphthyl structure, and its production method and use - Google Patents

Description

The present invention relates to a thermoplastic resin having a specific dicarboxylic acid component having a 1,1'-binaphthyl skeleton as a polymerization component, as well as a method for producing the same and uses thereof.

In recent years, the development of small or mobile devices such as smartphones and tablet PCs has been remarkable, and the development of devices with higher performance (higher functionality) is progressing. In addition, the spread of social networking services (SNS) has made it easy for individuals to disseminate information, and these devices are often equipped with optical functions such as cameras as well as image display functions. Therefore, as the performance of devices improves, the requirements for optical components are also increasing. For the optical components of these devices, resin materials are often used that are more advantageous than optical glass in terms of light weight, impact resistance (flexibility), moldability (productivity), etc., but existing resin materials may not be able to fully meet the increasing requirements, and there is a demand for the development of new resins with excellent optical properties and heat resistance.

In particular, imaging lens units mounted on small devices or mobile devices with camera functions are required to be smaller in size as the devices themselves become thinner and more multifunctional, while at the same time higher resolution is required as the imaging elements have a higher pixel count. For this reason, imaging lens units are designed with various ideas in the selection of lens configuration, shape, and material, and are optically designed to be small and high in imaging performance while being able to correct various aberrations. In general, imaging lens units are composed of multiple lenses with different Abbe numbers and refractive indexes, and are usually composed of a combination of lenses with high Abbe numbers and lenses with low Abbe numbers. However, since there are only a limited number of resin materials that can be used for optical lenses, there is a limit to the design of a variety of highly effective lens units. Therefore, if resins with various Abbe numbers can be prepared, the range of material selection can be expanded, the degree of freedom in design can be improved, and optimization of imaging lens units can be expected. From this perspective, the development of new optical resin materials is also required.

On the other hand, polyester resins with a 1,1'-binaphthyl structure are attracting attention as resin materials with excellent optical properties and heat resistance.

JP 2001-72872 A (Patent Document 1) discloses a resin containing, as a monomer component, a biaryl compound bonded via a bond axis capable of imparting internal rotational isomerism, and in which at least one of the aryl groups has a π electron count of 4n+6 (n is a natural number) relative to the bond axis. It is described that a resin composition containing such a resin is useful as a resin for forming optical lenses, since it has excellent transparency, small optical anisotropy (birefringence), a high refractive index, and low moisture absorption.

In addition, JP 2017-171885 A (Patent Document 2) discloses a polyester resin containing a structural unit represented by the following formula (1) and/or a structural unit represented by the following formula (2) and a structural unit represented by the following formula (3).

(In the formula, A ¹ is a direct bond or an alkylene group, A ² is an alkylene group, L ₁ is an alkylene group, R ¹ and R ² are substituents, h is 0 or 1, n is an integer of 0 or more, m is an integer of 0 to 2, and k is an integer of 0 to 4.)

(In the formula, ^A3 is an alkylene group, _L2 is an alkylene group, ^R3 and ^R4 are substituents, j is 0 or 1, p is an integer of 0 or more, q is an integer of 0 to 2, and r is an integer of 0 to 4.)

(In the formula, ring Z is an arene ring, ^A4 is an alkylene group, ^R5 and ^R6 are substituents, s is an integer of 0 or more, t is an integer of 0 to 4, and u is an integer of 0 or more).

JP 2001-72872 A JP 2017-171885 A

In the examples of Patent Document 1, various biaryl compounds having a 1,1'-binaphthyl skeleton, for example, dicarboxylic acid components such as 2,2'-bis(chlorocarbonylmethoxy)-1,1'-binaphthyl [compound (1-21)], 2,2'-bis(methoxycarbonylmethoxy)-1,1'-binaphthyl [compound (1-23)], or 4,4'-bis(methoxycarbonylmethoxy)-1,1'-binaphthyl [compound (1-24)], are used as polymerization components (monomer components) to synthesize polyester resins, and the resulting resin is then injection molded to produce an optical lens.

However, the examples in Patent Document 1 do not specifically describe optical properties such as refractive index, birefringence, and Abbe number, or heat resistance.

Patent Document 2 describes that it is possible to achieve both a high refractive index and low birefringence, which are in a trade-off relationship, and further describes that it has a low Abbe number and is excellent in heat resistance, moldability, and mechanical properties. It also describes that, with respect to formula (1), h is preferably 1 from the viewpoint of reactivity, and further describes that the group -[O-(A ² O) _n -L ₁ ] _h -CO- is preferably located at the 2-position (or 2'-position) of the naphthalene ring from the viewpoint of reducing birefringence.

In the examples of Patent Document 2, various polyester resins are prepared using 2,2'-bis(ethoxycarbonylmethoxy)-1,1'-binaphthyl (or BNAC-E) as a polymerization component, and it is described that the obtained polyester resins can achieve both a high refractive index and low birefringence, and are also excellent in heat resistance, mechanical properties, and moldability. It is also described that the Abbe numbers of the polyester resins of Examples 1 to 9, which contain BNAC-E as a polymerization component, were 18.4 to 20.2, and the Tg was 132.5 to 161.1°C.

In Patent Document 2, a polyester resin is obtained that exhibits relatively good properties, such as a low Abbe number, high heat resistance, a high refractive index, and low birefringence, but there is a demand for further improvement of these properties.

The object of the present invention is therefore to provide a thermoplastic resin having a low Abbe number and excellent heat resistance, a method for producing the same and uses thereof, and a monomer compound capable of forming the thermoplastic resin.

As a result of intensive research into achieving the above object, the inventors discovered that when a thermoplastic resin is prepared using a dicarboxylic acid or an ester-forming derivative thereof having a carboxyl group at a specific substitution position of the 1,1'-binaphthyl skeleton as a polymerization component, the resulting polyester resin exhibits a lower Abbe number and high heat resistance, and thus completed the present invention.

That is, the thermoplastic resin of the present invention is a thermoplastic resin containing a dicarboxylic acid unit (A), and the dicarboxylic acid unit (A) contains at least a first dicarboxylic acid unit (A1) represented by the following formula (1):

(In the formula, R ^1a and R ^1b each independently represent a hydrogen atom or a substituent,
R ^2a and R ^2b each independently represent a substituent, and k1 and k2 each independently represent an integer of 0 to 5).

In the formula (1), R ^1a and R ^1b may be an alkoxy group. The first dicarboxylic acid unit (A1) represented by the formula (1) may contain a dicarboxylic acid unit represented by the following formula (1a):

(In the formula, R ^1a and R ^1b , R ^2a and R ^2b , k1 and k2 are the same as in formula (1)).

The dicarboxylic acid unit (A) may contain a second dicarboxylic acid unit (A2) represented by the following formula (2a) or (2b):

(In the formula, R ^4a represents a substituent, m1 represents an integer of 0 to 8,
A ^1a and A ^1b each independently represent a divalent hydrocarbon group which may have a substituent;
R ^4b represents a substituent; m2 represents an integer of 0 to 8;
A ^1c represents a divalent hydrocarbon group which may have a substituent;
m3 represents an integer of 0 to 4).

The ratio of the first dicarboxylic acid unit (A1) to the second dicarboxylic acid unit (A2) may be the former/latter (molar ratio) = approximately 30/70 to 95/5.

The thermoplastic resin may be a polyester resin further containing a diol unit (B). The diol unit (B) may contain at least one diol unit selected from a first diol unit (B1) represented by the following formula (3), a second diol unit (B2) represented by the following formula (4), and a third diol unit (B3) represented by the following formula (5).

(In the formula, ^A2 represents a linear or branched alkylene group, and n represents an integer of 1 or more).

(In the formula, ^Z1 and ^Z2 each independently represent an aromatic hydrocarbon ring;
^R5 represents a substituent; p represents an integer of 0 to 8;
R ^6a and R ^6b each independently represent a substituent; q1 and q2 each independently represent 0 or an integer of 1 or more;
^A3a and ^A3b each independently represent a linear or branched alkylene group, and r1 and r2 each independently represent 0 or an integer of 1 or more.

(In the formula, ^A4 represents a direct bond or an alkylene group,
^A5a and ^A5b each represent a linear or branched alkylene group; s1 and s2 each independently represent 0 or an integer of 1 or more;
R ^7a and R ^7b each independently represent a substituent, and t1 and t2 each independently represent an integer of 0 to 6).

In the formula (3), ^A2 may be a linear or branched _C2-6 alkylene group, and n may be an integer of about 1 to 5;
In the formula (4), Z ¹ and Z ² are monocyclic aromatic hydrocarbon rings or condensed polycyclic aromatic hydrocarbon rings, A ^3a and A ^3b are linear or branched C _2-6 alkylene groups, and r1 and r2 may be integers of about 0 to 10;
In the formula (5), A ⁴ may be a direct bond or a C _1-2 alkylene group, A ^5a and A ^5b may be linear or branched C _2-6 alkylene groups, and s1 and s2 may be integers of about 0 to 10.

The ratio of the first diol unit (B1) may be about 1 mol % or more relative to the total diol unit (B). The ratio of the first diol unit (B1) to the second diol unit (B2) may be the former/latter (molar ratio) of about 1/99 to 50/50. The ratio of the first diol unit (B1) to the third diol unit (B3) may be the former/latter (molar ratio) of about 5/95 to 50/50.

The present invention includes a method for producing the thermoplastic resin by polymerizing a polymerization component that contains at least a first dicarboxylic acid component corresponding to the first dicarboxylic acid unit (A1).

The present invention also includes a compound represented by the following formula (1A):

(In the formula, R ^1a and R ^1b each independently represent a C _1-5 alkoxy group,
R ^3a and R ^3b each independently represent a C _1-5 alkoxy group;
R ^2a and R ^2b , k1 and k2 are the same as in formula (1) above.

Furthermore, the present invention includes an Abbe number reducer represented by the following formula (1B):

(In the formula, R ^3a and R ^3b each independently represent a hydroxyl group, an alkoxy group, or a halogen atom,
R ^1a and R ^1b , R ^2a and R ^2b , k1 and k2 are the same as those in formula (1).

The present invention also includes a resin composition containing a thermoplastic resin and the Abbe number reducer.

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

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

In the present specification and claims, the term "dicarboxylic acid component" is used to mean not only dicarboxylic acid but also its ester-forming derivatives. Examples of the ester-forming derivatives include alkyl esters, acid halides, and acid anhydrides. Examples of the alkyl esters include lower alkyl esters, such as C _1-4 alkyl esters, such as methyl esters, ethyl esters, and t-butyl esters. The ester-forming derivatives may be monoesters (half esters) or diesters.

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 thermoplastic resin that can achieve four properties that are difficult to achieve simultaneously, namely a low Abbe number, a high refractive index, low birefringence, and high heat resistance, at an even higher level in a well-balanced manner, a method for producing the same, uses thereof, and a monomer compound capable of forming the thermoplastic resin.

Yet another object of the present invention is to provide a thermoplastic resin that can be efficiently polymerized to a relatively high molecular weight and has excellent moldability (productivity) despite containing a 1,1'-binaphthyl skeleton that is rigid and bulky and is expected to have reduced polymerization reactivity due to the effects of steric hindrance, a method for producing the same, uses thereof, and a monomer compound capable of forming the thermoplastic resin.

Another object of the present invention is to provide an Abbe number reducer that can reduce the Abbe number of a thermoplastic resin.

In this specification and claims, the number of carbon atoms in a substituent may be indicated as _C1 , _C6 , _C10 , etc. For example, an alkyl group having one carbon atom is indicated as a " _C1 alkyl" and an aryl group having 6 to 10 carbon atoms is indicated 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 thermoplastic resin of the present invention uses a dicarboxylic acid or its ester-forming derivative having a carboxyl group at a specific substitution position of the 1,1'-binaphthyl skeleton as a polymerization component, and therefore can greatly reduce the Abbe number and has excellent heat resistance. In addition, it can achieve four properties that are difficult to achieve simultaneously: low Abbe number, high refractive index, low birefringence, and high heat resistance, at an even higher level and in a well-balanced manner. Furthermore, despite containing a 1,1'-binaphthyl skeleton that is rigid and bulky and is expected to reduce polymerization reactivity due to the influence of steric hindrance, it can be efficiently polymerized to prepare a relatively high molecular weight, and moldability (productivity) can also be improved. In particular, by adjusting the composition ratio to a specific ratio, in addition to the four properties, high moldability (productivity) can also be achieved (or both heat resistance and moldability can be achieved). In addition, the dicarboxylic acid or its ester-forming derivative can also be used as an Abbe number reducer.

[Thermoplastic resin]
The thermoplastic resin may contain at least a first dicarboxylic acid unit (A1) represented by the following formula (1) as the dicarboxylic acid unit (A). Examples of such thermoplastic resins include polyamide-based resins and polyester-based resins, and polyester-based resins are preferred because they have low water absorption and are easy to use as optical members. Examples of polyester-based resins include polyester resins and polyester carbonate resins, and polyester resins are preferred.

(Dicarboxylic acid unit (A))
First Dicarboxylic Acid Unit (A1)

(In the formula, R ^1a and R ^1b each independently represent a hydrogen atom or a substituent,
R ^2a and R ^2b each independently represent a substituent, and k1 and k2 each independently represent an integer of 0 to 5).

When the dicarboxylic acid unit (A) contains the first dicarboxylic acid unit (A1), the Abbe number can be significantly reduced and the heat resistance can be significantly improved. In addition, the first dicarboxylic acid unit (A1) can achieve both a high refractive index and a low birefringence, which are usually in a trade-off relationship, so that the heat resistance and optical properties (low Abbe number, high refractive index, low birefringence) described above can be satisfied in a well-balanced manner. Furthermore, despite containing a rigid and bulky binaphthyl skeleton, the first dicarboxylic acid unit (A1) is surprisingly highly polymerizable, and can effectively improve the moldability, handling (productivity), mechanical strength, etc. of the thermoplastic resin.

In the formula (1), the substituents represented by R ^1a and R ^1b are preferably substituents that are inactive in the polymerization reaction.

In this specification and claims, "substituents inactive to polymerization reactions" refers to non-polymerizable groups that do not contain polymerizable groups that participate in the formation of bonds on the main chain of a thermoplastic resin, such as ester bonds or amide bonds. In other words, it refers to substituents (non-reactive substituents) excluding ester- or amide-forming substituents such as hydroxyl groups, carboxyl groups, alkoxycarbonyl groups, halocarbonyl groups, acid anhydride groups, and amino groups, and substituents that contain these groups in their chemical structure, such as hydroxy(poly)alkoxy groups and carboxy(poly)alkoxy groups.

The substituents represented by R ^1a and R ^1b are preferably electron-donating groups, since they facilitate the formation of a 1,1'-binaphthyl skeleton and provide excellent productivity.

Examples of the electron-donating group include hydrocarbon groups such as alkyl groups and aryl groups, hydroxyl groups, alkoxy groups, acyloxy groups, and mono- or di-substituted amino groups, and may be electron-donating groups that do not contain hydroxyl groups.

Examples of the alkyl group include C _1-6 alkyl groups such as methyl group, ethyl group, etc. Examples of the aryl group include C _6-12 aryl groups such as phenyl group, etc.

Examples of the alkoxy group include C _1-6 alkoxy groups such as methoxy group, ethoxy group, propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, s-butoxy group, and t-butoxy group. Examples of the acyloxy group include C _2-7 acyloxy groups such as acetoxy group (methylcarbonyloxy group).

Examples of the mono- or di-substituted amino group include mono- or di-alkylamino groups, specifically, mono- or di-C _1-6 alkylamino groups such as a dimethylamino group; mono- or di-C _2-7 acylamino groups, specifically, monoacetylamino group (N-methylcarbonylamino group); and the like.

Preferred groups R ^1a and R ^1b are hydrogen atoms or alkoxy groups, with hydrogen atoms being preferred from the viewpoint of improving polymerization reactivity and suppressing fluctuations in the refractive index and dimensions of the molded article due to water absorption (or improving refractive index stability and dimensional stability), and alkoxy groups such as linear or branched C _1-5 alkoxy groups being particularly preferred from the viewpoint of improving the refractive index stability, dimensional stability, and productivity in a well-balanced manner. Among alkoxy groups, linear or branched C _1-4 alkoxy groups are preferred, linear or branched C _1-3 alkoxy groups are more preferred, and C _1-2 alkoxy groups such as methoxy groups are particularly preferred. The types of R ^1a and R ^1b may be different from each other, but are usually often the same.

R ^2a and R ^2b are preferably substituents that are inactive in a polymerization reaction (non-polymerizable groups), and examples thereof include halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms; hydrocarbon groups (or groups R ^h ) such as alkyl groups, cycloalkyl groups, aryl groups, and aralkyl groups; groups -OR ^h (wherein R h represents the above-mentioned hydrocarbon groups) corresponding to the above-mentioned hydrocarbon groups, such as alkoxy groups, cycloalkyloxy groups, aryloxy groups, and aralkyloxy groups; groups -SR ^h (wherein R ^h represents the above-mentioned hydrocarbon groups) corresponding to the above-mentioned hydrocarbon groups, such as alkylthio groups, cycloalkylthio groups, ^arylthio groups, and aralkylthio groups; acyl groups; nitro groups; cyano groups; and substituted amino groups.

Examples of the alkyl group represented by ^Rh include linear or branched C _{1-10 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, isobutyl, and t-butyl groups, preferably linear or branched C 1-6 alkyl} groups, and more preferably linear or branched C _1-4 alkyl groups.

Examples of the cycloalkyl group represented by ^Rh include a C _5-10 cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, and the like.

Examples of the aryl group represented by ^Rh include C _6-12 aryl groups such as a phenyl group, an alkylphenyl group, a biphenylyl group, and a naphthyl group. Examples of the alkylphenyl group include a methylphenyl group (tolyl group) and a dimethylphenyl group (xylyl group).

Examples of the aralkyl group represented by ^Rh 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 groups corresponding to the above-exemplified hydrocarbon groups R ^h , including preferred embodiments thereof, such as linear or branched C _1-10 alkoxy groups such as a methoxy group, C _5-10 cycloalkyloxy groups such as a cyclohexyloxy group, C _6-10 aryloxy groups such as a phenoxy group, and C _6-10 aryl-C _1-4 alkyloxy groups such as a benzyloxy group.

Examples of the group ^-SRh include groups corresponding to the above-exemplified hydrocarbon groups ^Rh , including preferred embodiments thereof, such as linear or branched C _1-10 alkylthio groups such as a methylthio group, C _5-10 cycloalkylthio groups such as a cyclohexylthio group, C _6-10 arylthio groups such as a thiophenoxy group (phenylthio group), and C _6-10 aryl-C _1-4 alkylthio groups such as a benzylthio group.

Examples of the acyl group include C _1-6 acyl groups such as an acetyl group.

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

Of these substituents, halogen atoms such as bromine atoms are preferred.

The substitution numbers k1 and k2 of R ^2a and R ^2b may be, for example, integers of about 0 to 4, and the preferred ranges are, in the following stepwise order, integers of 0 to 3, integers of 0 to 2, more preferably 0 or 1, and particularly preferably 0. k1 and k2 may be different from each other, but are preferably the same. Furthermore, when k1 is 2, the types of the two R ^2a may be the same or different from each other, and when k2 is 2, the types of the two R ^2b may be the same or different from each other. Furthermore, the types of R ^2a and R ^2b may be the same or different from each other.

The substitution positions of R ^2a and R ^2b are positions other than the bonding positions (2,2' positions) of R ^1a and R ^1b in the 1,1'-binaphthyl skeleton and the bonding position of the carbonyl group [-C(=O)-] forming the main chain of the thermoplastic resin, i.e., any position selected from the 3-8 positions and the 3'-8' positions, and preferably any position selected from the 3-5 positions, the 7-8 positions, the 3'-5' positions, and the 7'-8' positions.

In formula (1), the bonding positions of the two carbonyl groups [-C(=O)-] forming the main chain of the thermoplastic resin may be any of the 5-8 and 5'-8' positions (i.e., the benzene ring opposite the benzene ring directly bonded at the 1,1' position in the 1,1'-binaphthyl skeleton), but are preferably the 5,5', 6,6', or 7,7' positions, and more preferably the 6,6' positions as represented by the following formula (1a).

(In the formula, R ^1a and R ^1b , R ^2a and R ^2b , k1 and k2 are the same as in formula (1) including preferred embodiments).

Representative first dicarboxylic acid components corresponding to the first dicarboxylic acid unit (A1) include dicarboxylic acid components corresponding to a unit in which R ^1a and R ^1b are alkoxy groups, for example, 6,6'-dicarboxy-2,2'-dialkoxy-1,1'-binaphthyl, specifically 6,6'-dicarboxy-2,2'-diC 1-6 alkoxy-1,1'-binaphthyl such as 6,6'-dicarboxy-2,2'-dimethoxy-1,1'-binaphthyl and 6,6'-dicarboxy- _2,2' -diethoxy-1,1'-binaphthyl, and ester-forming derivatives thereof.

The first dicarboxylic acid unit (A1) may be contained alone or in combination of two or more kinds. Among the first dicarboxylic acid units (A1), a constitutional unit derived from 6,6'-dicarboxy-2,2'-diC _1-4 alkoxy-1,1'-binaphthyl such as 6,6'-dicarboxy-2,2'-dimethoxy-1,1'-binaphthyl is preferred from the viewpoint of productivity and the like.

The ratio of the structural units represented by the formula (1a), particularly the ratio of the dicarboxylic acid units corresponding to 6,6'-dicarboxy-2,2'-dialkoxy-1,1'-binaphthyl, can be selected from a range of, for example, 1 mol% or more, specifically, about 10 to 100 mol%, based on the entire first dicarboxylic acid unit (A1). Preferred ranges are, in the following stepwise order, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and more preferably 100 mol%. In other words, it is preferable that the first dicarboxylic acid unit (A1) is substantially formed only from the structural units represented by the formula (1a), particularly only from the dicarboxylic acid units corresponding to 6,6'-dicarboxy-2,2'-dialkoxy-1,1'-binaphthyl.

Second Dicarboxylic Acid Unit (A2)
The dicarboxylic acid unit (A) may or may not contain a second dicarboxylic acid unit (A2) represented by the following formula (2a) or (2b), as necessary.

(In the formula, R ^4a represents a substituent, m1 represents an integer of 0 to 8,
A ^1a and A ^1b each independently represent a divalent hydrocarbon group which may have a substituent;
R ^4b represents a substituent; m2 represents an integer of 0 to 8;
A ^1c represents a divalent hydrocarbon group which may have a substituent;
m3 represents an integer of 0 to 4).

When the second dicarboxylic acid unit (A2) is contained, it is easy to reduce birefringence while maintaining a relatively high refractive index, and even if the polymer has a rigid fluorene skeleton, it tends to be easy to improve polymerization reactivity.

In the formula (2a) or (2b), the substituents represented by R ^4a and R ^4b are preferably substituents that are inactive in a polymerization reaction (non-polymerizable groups), and examples thereof include a cyano group; a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom; and a hydrocarbon group such as an alkyl group or an aryl group.

Examples of the alkyl group include linear or branched _C1-12 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and t-butyl groups, etc. Examples of the aryl group include _C6-10 aryl groups such as phenyl and naphthyl groups.

Of these substituents ^R4a and ^R4b , when the number of substitutions m1 and m2 is 1 or more, a cyano group, a halogen atom, an alkyl group or an aryl group is preferred, an alkyl group or an aryl group is more preferred, and an aryl group is even more preferred. Preferred alkyl groups include linear or branched _C1-8 alkyl groups, more preferably linear or branched _C1-4 alkyl groups such as methyl groups. Preferred aryl groups include _C6-10 aryl groups, more preferably naphthyl groups.

The substitution numbers m1 and m2 may each be an integer of, for example, about 0 to 6, and the preferred ranges are, in the following stepwise order, integers from 0 to 4, integers from 0 to 3, and integers from 0 to 2, with 0 or 1 being more preferred, and 0 being particularly preferred.

In addition, when the substitution numbers m1 and m2 of the groups R ^4a and R ^4b are 2 or more, the types of the two or more groups R ^4a and R ^4b may be the same or different from each other. The bonding positions (substitution positions) of R ^4a and R ^4b are not particularly limited, and examples thereof include the 2-position, 7-position, and 2,7-position of the fluorene ring.

In particular, when the substituents R ^4a and R ^4b are aryl groups such as naphthyl groups, the Abbe number can be reduced. When the substituents R ^4a and R ^4b are aryl groups such as naphthyl groups, m1 and m2 are each, for example, 1 to 6, preferably 1 to 4, more preferably 1 to 3, and even more preferably 2. When m1 and m2 are 2, the substitution positions of the substituents R ^4a and R ^4b are preferably the 2- and 7-positions.

Examples of the hydrocarbon group represented by groups A ^1a , A ^1b and A ^1c include linear or branched alkylene groups, for example, linear or branched C _1-8 alkylene groups such as methylene, ethylene, trimethylene, propylene, 1,2-butanediyl and 2-methylpropane-1,3-diyl groups. Preferred alkylene groups include linear or branched C _1-6 alkylene groups such as methylene, ethylene, trimethylene, propylene and 2-methylpropane-1,3-diyl groups, and more preferably linear or branched C _1-4 alkylene groups.

The substituent that the hydrocarbon group may have is preferably a substituent that is inactive in the polymerization reaction (non-polymerizable group), and examples thereof include aryl groups such as a phenyl group, and cycloalkyl groups such as a cyclohexyl group, etc. The hydrocarbon groups A ^1a , A ^1b , and A ^1c having a substituent may be, for example, a 1-phenylethylene group, a 1-phenylpropane-1,2-diyl group, etc.

The groups A ^1a and A ^1b are preferably linear or branched C _2-4 alkylene groups, particularly linear or branched C _2-3 alkylene groups such as ethylene and propylene groups, and particularly preferably ethylene groups. The group A ^1c is preferably linear or branched C _1-3 alkylene groups such as methylene and ethylene groups. The types of A ^1a and A ^1b may be different from each other, but are preferably the same.

In the formula (2b), the number of repeating methylene groups, m3, is, for example, an integer of about 0 to 3, preferably an integer of 0 to 2, and more preferably 0 or 1.

Representative examples of the second dicarboxylic acid component corresponding to the constitutional unit represented by the formula (2a) include dicarboxylic acid components in which A ^1a and A ^1b correspond to linear or branched C _2-6 alkylene groups, 9,9-bis(carboxy C 2-6 alkyl)fluorenes such as 9,9-bis(2-carboxyethyl)fluorene and 9,9-bis( ₂ -carboxypropyl)fluorene, 9,9-bis(carboxy C _2-6 alkyl)-di C _6-10 arylfluorenes such as 9,9-bis(2-carboxyethyl)-2,7-di(2-naphthyl)fluorene, and ester-forming derivatives thereof.

Representative examples of the second dicarboxylic acid component corresponding to the constitutional unit represented by the formula (2b) include 9-(dicarboxyC _2-8 alkyl)fluorene and ester-forming derivatives thereof, specifically, dicarboxylic acid components in which m3 is 0 and A ^{1c corresponds to a linear or branched C 1-6 alkylene group, such as 9-(1,2-dicarboxyethyl)fluorene and 9-(1,2-dicarboxyethyl)-2,7-di(2-naphthyl)fluorene; and dicarboxylic acid components in which m3 is 1 and A 1c} _{corresponds to a linear or branched C 1-6} ^alkylene _group , such as 9-(2,3-dicarboxypropyl)fluorene and 9-(2,3-dicarboxypropyl)-2,7-di(2-naphthyl)fluorene.

The second dicarboxylic acid unit (A2) derived from these second dicarboxylic acid components (A2) may be contained alone or in combination of two or more. Among these second dicarboxylic acid units (A2), from the viewpoint of easiness in reducing birefringence, it is preferable to contain at least a dicarboxylic acid unit represented by the above formula (2a), and more preferable is a structural unit derived from 9,9-bis(carboxyalkyl)fluorene such as 9,9-bis(carboxyC _2-6 alkyl)fluorene. Among them, it is preferable to contain a structural unit derived from 9,9-bis(carboxyC _2-4 alkyl)fluorene, more preferably 9,9-bis(carboxyC _2-3 alkyl)fluorene such as 9,9-bis(2-carboxyethyl)fluorene and 9,9-bis(2-carboxypropyl)fluorene, and in particular 9,9-bis(2-carboxyethyl)fluorene.

The proportion of the structural units represented by the formula (2a), particularly the proportion of the dicarboxylic acid units corresponding to 9,9-bis(carboxyalkyl)fluorene, can be selected from a range of, for example, 1 mol% or more, specifically, about 10 to 100 mol%, based on the entire second dicarboxylic acid units (A2). Preferred ranges are, in the following stepwise order, 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more, and more preferably 100 mol%. In other words, it is preferable that the second dicarboxylic acid units (A2) are substantially formed only from the structural units represented by the formula (2a), particularly only from the dicarboxylic acid units corresponding to 9,9-bis(carboxyalkyl)fluorene.

Third Dicarboxylic Acid Unit (A3)
In addition, the dicarboxylic acid unit (A) may or may not contain a third dicarboxylic acid unit (A3) different from the first dicarboxylic acid unit (A1) and the second dicarboxylic acid unit (A2), as necessary.

Examples of the third dicarboxylic acid unit (A3) include structural units derived from an aromatic dicarboxylic acid component (excluding the first dicarboxylic acid unit (A1) and the second dicarboxylic acid unit (A2)), an alicyclic dicarboxylic acid component, an aliphatic dicarboxylic acid component, etc.

Examples of the aromatic dicarboxylic acid component include monocyclic aromatic dicarboxylic acids, polycyclic aromatic dicarboxylic acids, and ester-forming derivatives thereof. Examples of the monocyclic aromatic dicarboxylic acids include benzene dicarboxylic acids such as phthalic acid, terephthalic acid, and isophthalic acid; alkyl benzene dicarboxylic acids, specifically, C _1-4 alkyl-benzene dicarboxylic acids such as 4-methylisophthalic acid; and the like.

Examples of polycyclic aromatic dicarboxylic acids include condensed polycyclic aromatic dicarboxylic acids, specifically condensed polycyclic C 10-24 arene-dicarboxylic acids such as naphthalenedicarboxylic acid, anthracene dicarboxylic acid, and phenanthrene dicarboxylic acid, preferably condensed polycyclic C _10-14 arene-dicarboxylic acids; biaryl dicarboxylic acids, specifically bi-C _6-10 aryl-dicarboxylic acids such as 2,2'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and 3,3'-dicarboxy-1,1'-binaphthyl; bis(carboxyalkoxy)bi-C _6-10 aryl, specifically bis(carboxy C 1-4 alkoxy)bi-C _6-10 aryl such as 2,2'-bis(carboxymethoxy)-1,1'-binaphthyl; bis[(carboxyalkoxy)-C _6-10 aryl]alkane, specifically bis[(carboxy C _1-4 alkoxy)bi-C _6-10 aryl]alkane such as bis[2-(carboxymethoxy)-1-naphthyl]methane; diarylalkane dicarboxylic acids, specifically, di(C _6-10 aryl) ketone-dicarboxylic acids such as _4.4' - _{diphenylketone} dicarboxylic acid; diaryl ether dicarboxylic acids, specifically, di(C _6-10 aryl) ether-dicarboxylic acids such as _{4.4' -} diphenylether dicarboxylic acid; diaryl sulfone dicarboxylic acids, specifically, _{di(C 6-10 aryl} ) sulfone-dicarboxylic acids such as 4.4'-diphenylsulfone dicarboxylic acid.

Examples of the naphthalenedicarboxylic acid include 1,2-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid, with 2,3-naphthalenedicarboxylic acid being the most common.

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, bi- 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, bi- or tricycloalkene dicarboxylic acids such as norbornene dicarboxylic acid; and ester-forming derivatives thereof.

Examples of the aliphatic dicarboxylic acid component include alkane dicarboxylic acids, specifically, C _2-18 alkane-dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, decanedicarboxylic acid, and dodecane dicarboxylic 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.

These dicarboxylic acid components can be used alone or in combination of two or more. Among these, as the third dicarboxylic acid unit (A3), benzene dicarboxylic acids such as terephthalic acid and C _2-12 alkane dicarboxylic acids such as dodecane dicarboxylic acid are preferred from the viewpoint of improving moldability.

The total proportion of the first dicarboxylic acid unit (A1) and the second dicarboxylic acid unit (A2) can be selected, for example, from 1 mol% or more, specifically from about 10 to 100 mol%, based on the total dicarboxylic acid unit (A). Preferred ranges are 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, and 95 mol% or more in the following stepwise order. It is particularly preferred that the total proportion is 100 mol%, substantially free of the third dicarboxylic acid unit (A3).

The proportion of the first dicarboxylic acid unit (A1) can be selected from, for example, 1 mol% or more, specifically, about 10 to 100 mol%, based on the total dicarboxylic acid unit (A). Preferred ranges are 20 to 100 mol%, 30 to 100 mol%, 40 to 95 mol%, and 45 to 92 mol% or more in the following stepwise order. From the viewpoint of improving excellent optical properties (low Abbe number, high refractive index, and low birefringence) and heat resistance in a more balanced manner, it is 40 to 80 mol%, preferably 45 to 75 mol%. If the proportion of the first dicarboxylic acid unit (A1) is too small, the Abbe number cannot be sufficiently reduced or the heat resistance cannot be sufficiently improved, so that it may be difficult to achieve a balanced balance between heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence).

The ratio of the first dicarboxylic acid unit (A1) to the second dicarboxylic acid unit (A2) (hereinafter simply referred to as A1/A2) may be selected from the range of, for example, A1/A2 (molar ratio) = about 1/99 to 100/0, and the preferred ranges are as follows, in stages: 10/90 to 99/1, 30/70 to 95/5, 40/60 to 93/7, 45/55 to 92/8, and 50/50 to 90/10. In applications where low birefringence is important, A1/A2 (molar ratio) = 40/60 to 80/20, preferably 45/55 to 70/30, may be used. If the ratio of the first dicarboxylic acid unit (A1) is too small, the glass transition temperature may decrease, resulting in a decrease in heat resistance, or the Abbe number may not be sufficiently reduced, or the refractive index may decrease. On the other hand, if the proportion of the second dicarboxylic acid unit (A2) is too small, birefringence may not be sufficiently reduced.

When the dicarboxylic acid unit (A) is combined with the first diol unit (B1) described below, the molar ratio A1/A2 may be selected from a range of about 40/60 to 100/0, with preferred ranges being 50/50 to 99/1, 60/40 to 98/2, 70/30 to 97/3, 80/20 to 96/4, and 85/15 to 95/5, in the following stepwise order. Combining the dicarboxylic acid unit (A) with the first diol unit (B1) in such a ratio appears to be able to further reduce the Abbe number and greatly improve heat resistance.

When the dicarboxylic acid unit (A) is combined with the second diol unit (B2) described later, the molar ratio A1/A2 may be selected from the range of about 10/90 to 100/0, and preferred ranges are 20/90 to 95/5, 30/70 to 90/10, 35/65 to 85/15, 40/60 to 80/20, and 45/55 to 75/25, in the following stepwise order. When combined with the second diol unit (B2) in such a ratio, it appears that excellent optical properties (low Abbe number, high refractive index, and low birefringence) can be exhibited while the heat resistance can be greatly improved, and the composition is suitable for applications requiring durability in high temperature environments, such as in-vehicle lenses. In particular, when combined with a second diol unit (B2) in which Z ¹ and Z ² in formula (4) are condensed polycyclic aromatic hydrocarbon rings such as naphthalene rings, the molar ratio A1/A2 may be selected from a range of about 30/70 to 70/30, and preferred ranges are 35/65 to 65/35, 40/60 to 60/40, and 45/55 to 55/45 in the following stepwise order. When combined with the second diol unit (B2) in such a ratio, it appears that the refractive index and heat resistance in particular can be further improved while high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) are satisfied in a well-balanced manner. On the other hand, when combined with a second diol unit (B2) in which Z ¹ and Z ² in formula (4) are benzene rings (monocyclic aromatic hydrocarbon rings), the molar ratio A1/A2 may be selected from a range of about 50/50 to 90/10, and preferred ranges are 55/45 to 85/15, 60/40 to 80/20, and 65/35 to 75/25 in the following stepwise order. When combined with the second diol unit (B2) in such a ratio, it appears that birefringence in particular can be more effectively reduced and heat resistance can be greatly improved while high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) are satisfied in a well-balanced manner.

When the dicarboxylic acid unit (A) is combined with the third diol unit (B3) described below, the A1/A2 (molar ratio) may be selected from a range of about 50/50 to 90/10, with preferred ranges being 55/45 to 85/15, 60/40 to 80/20, and 65/35 to 75/25, in the following stepwise order. Combining with the third diol unit (B3) in such a ratio provides a particularly excellent balance of high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence), and also provides good moldability, making this the most preferred ratio.

[Diol unit (B)]
The thermoplastic resin is preferably a polyester resin containing a diol unit (B) in addition to the dicarboxylic acid unit (A). The diol unit (B) is not particularly limited, but preferably contains at least one diol unit selected from the first diol unit (B1) represented by the following formula (3), the second diol unit (B2) represented by the following formula (4), and the third diol unit (B3) represented by the following formula (5), and more preferably contains at least the first diol unit (B1).

First diol unit (B1)

(In the formula, ^A2 represents a linear or branched alkylene group, and n represents an integer of 1 or more).

When the first diol unit (B1) is included, it is easy to increase the molecular weight by increasing the polymerization reactivity, and it is also possible to impart flexibility or toughness to the thermoplastic resin, thereby greatly improving moldability and handling properties.

In the formula (3), examples of the alkylene group represented by ^A2 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 ^A2 are, in the following order, linear or branched _C2-10 alkylene groups, linear or branched _C2-8 alkylene groups, linear or branched _C2-6 alkylene groups, and linear or branched _C2-4 alkylene groups, more preferably linear or branched _C2-3 alkylene groups such as ethylene and propylene, and particularly preferably ethylene.

The repeat number n of the alkyleneoxy group [-(A ² O)-] can be selected, for example, from the range of about 1 to 10, and preferred ranges are 1 to 8, 1 to 6, 1 to 4, 1 to 3, and 1 to 2 in the following stepwise order, with 1 being particularly preferred. The repeat number n may be an average value (arithmetic mean value or arithmetic mean value), and preferred embodiments may be the same as those in the range of integers described above. When n is 2 or more, the types of the two or more alkyleneoxy groups (-A ² O-) may be different from each other, but are usually often the same.

Examples of the first diol component corresponding to the first diol unit (B1) represented by the formula (3) include alkanediols (or alkylene glycols), polyalkanediols (or polyalkylene glycols), etc.

Examples of the alkylene glycol include compounds in which n is 1 and ^A2 corresponds to the alkylene group exemplified in the above 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 aspects are similar to those corresponding to the alkylene group ^A2 .

Examples of the polyalkylene glycol include compounds in which, in the above formula (3), n is 2 or more, preferably 2 to 10, more preferably 2 to 6, and even more preferably 2 to 4, and ^A2 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-linear or branched _C2-6 alkylene glycols, and more preferably di- to tetra-linear or branched _C2-4 alkylene glycols.

The first diol unit (B1) formed from these first diol components may be contained alone or in combination of two or more kinds. A preferred first diol unit (B1) is an alkylene glycol, from the viewpoint of easily maintaining high heat resistance, more preferably a linear or branched C _2-6 alkylene glycol, further preferably a linear or branched C _2-4 alkylene glycol such as ethylene glycol, propylene glycol, 1,4-butanediol, among which a linear or branched C _2-3 alkylene glycol such as ethylene glycol, propylene glycol, and particularly preferably a structural unit derived from ethylene glycol.

Second Diol Unit (B2)
The diol unit (B) may or may not contain a second diol unit (B2) represented by the following formula (4) as necessary. When the diol unit (B2) is contained, the optical properties (low Abbe number, high refractive index, and low birefringence) can be improved in a well-balanced manner while the heat resistance can be further improved, and the composition can be effectively used in applications requiring durability in high-temperature environments, such as in-vehicle lenses.

(In the formula, ^Z1 and ^Z2 each independently represent an aromatic hydrocarbon ring;
^R5 represents a substituent; p represents an integer of 0 to 8;
R ^6a and R ^6b each independently represent a substituent; q1 and q2 each independently represent 0 or an integer of 1 or more;
^A3a and ^A3b each independently represent a linear or branched alkylene group, and r1 and r2 each independently represent 0 or an integer of 1 or more.

While exhibiting excellent optical properties (low Abbe number, high refractive index, and low birefringence), it appears possible to significantly improve heat resistance, making it suitable for applications that require durability in high-temperature environments, such as automotive lenses.

In the formula (4), examples of the aromatic hydrocarbon ring (arene ring) represented by ^Z1 and ^Z2 include a monocyclic arene ring such as a benzene ring, and a polycyclic arene ring. The polycyclic arene ring includes a fused polycyclic aromatic hydrocarbon ring (fused polycyclic arene ring) and a ring-assembled aromatic hydrocarbon ring (ring-assembled arene ring).

Examples of the fused polycyclic arene ring include fused bicyclic arene rings, fused tricyclic arene rings, and other fused bicyclic to tetracyclic arene rings. Examples of the fused bicyclic arene ring include fused bicyclic C _10-16 arene rings such as naphthalene ring and indene ring, and examples of the fused tricyclic arene ring include anthracene ring and phenanthrene ring. Examples of the fused polycyclic arene ring include fused polycyclic C _10-16 arene rings such as naphthalene ring and anthracene ring, and more preferably fused polycyclic C _10-14 arene ring, and particularly preferably naphthalene ring.

Examples of the ring assembly arene ring include a biarene ring (or a biaryl ring) and a terarene ring (or a teraryl ring). Examples of the biarene ring include a biC _6-12 arene ring such as a biphenyl ring, a binaphthyl ring, and a phenylnaphthalene ring. Examples of the phenylnaphthalene ring include a 1-phenylnaphthalene ring and a 2-phenylnaphthalene ring. Examples of the terarene ring include a terC _6-12 arene ring such as a terphenylene ring. Examples of the ring assembly arene ring include a biC _6-10 arene ring, and a biphenyl ring is particularly preferred.

The types of Z ¹ and Z ² may be the same or different from each other, and are preferably the same. Among Z ¹ and Z ² , C _6-12 arene rings such as benzene rings, naphthalene rings, and biphenyl rings are preferred, and C _6-10 arene rings such as benzene rings and naphthalene rings are more preferred. In addition, from the viewpoint of being able to further improve the refractive index and heat resistance while satisfying high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) in a well-balanced manner, it is more preferable that Z ¹ and Z ² are condensed polycyclic arene rings such as naphthalene rings, while from the viewpoint of being able to more effectively reduce birefringence and greatly improve heat resistance while satisfying high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) in a well-balanced manner, it is more preferable that Z ¹ and Z ² are benzene rings.

The substitution positions of ^Z1 and ^Z2 bonded to the 9-position of the fluorene ring are not particularly limited. For example, when ^Z1 and ^Z2 are benzene rings, they may be any positions. When ^Z1 and ^Z2 are naphthalene rings, they are either the 1- or 2-position, preferably the 2-position. When ^Z1 and ^Z2 are biphenyl rings, they are either the 2-, 3- or 4-position, preferably the 3-position.

The substituent represented by ^R5 is preferably a substituent that is inactive in the polymerization reaction (non-polymerizable group), and examples thereof include the same substituents as the groups ^R4a and ^R4b described in the sections on formulas (2a) and (2b), including preferred embodiments thereof.

The number of substitutions p of ^R5 is the same as m1 and m2 described in the sections for formulae (2a) and (2b), including preferred embodiments, and is particularly preferably 0.

When the number of substitutions p is 2 or more, the types of the two or more groups ^R5 may be the same or different from each other. The bonding positions (substitution positions) of the group ^R5 on the two benzene rings constituting the fluorene ring are not particularly limited, and examples thereof include the 2-position, 7-position, and 2,7-position of the fluorene ring.

The substituents represented by R ^6a and R ^6b are preferably substituents inactive to polymerization reactions (non-polymerizable groups), and examples thereof include the same groups as those exemplified as the substituents R ^2a and R ^2b in the section on formula (1) above. Representative examples of R ^6a and R ^6b 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 q1 and q2 is 1 or more, preferred examples of R ^6a and R ^6b include alkyl groups, cycloalkyl groups, aryl groups, and alkoxy groups, and more preferred examples of R 6a and R 6b 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 in particular, linear or branched _C1-4 alkyl groups such as methyl groups and _C6-10 aryl groups such as phenyl groups are preferred. When the groups ^R6a and ^R6b are aryl groups, ^R6a and ^R6b may form the ring assembly arene ring together with the rings ^Z1 and ^Z2 , respectively.

The number of substitutions q1 and q2 of R ^6a and R ^6b may be an integer of 0 or more, and may be appropriately selected according to the type of rings Z ¹ and Z ^2. For example, it may be an integer of about 0 to 8. The preferred ranges are, in the following stepwise order, integers of 0 to 6, integers of 0 to 4, integers of 0 to 3, and integers of 0 to 2, with 0 or 1 being more preferred, and 0 being particularly preferred. q1 and q2 may be different from each other, but are preferably the same. Also, when q1 and q2 are 2 or more, the types of R ^6a and R ^6b that are 2 or more may be the same or different from each other. Also, the types of R ^6a and R ^6b may be the same or different from each other. In particular, when q1 and q2 are 1, Z ¹ and Z ² may be benzene rings, naphthalene rings, or biphenyl rings, and R ^6a and R ^6b may be methyl groups. The substitution positions of R ^6a and R ^6b are not particularly limited as long as they are substituted at a position other than the bonding position between Z ¹ and Z ² and the ether bond (-O-) forming the main chain and the 9-position of the fluorene ring. For example, they may be substituted at the ortho position (the carbon atom adjacent to the bonding position of the ether bond) with respect to the ether bond (-O-) in Z ¹ and Z ² .

Examples of the alkylene groups A ^3a and A ^3b include linear or branched C _2-6 alkylene groups such as ethylene group, propylene group (1,2-propanediyl group), trimethylene group, 1,2-butanediyl group, and tetramethylene group, and are preferably linear or branched C _2-4 alkylene groups, more preferably linear or branched C _2-3 alkylene groups such as ethylene group and propylene group, and particularly preferably ethylene group.

The repeat numbers (number of added moles) r1 and r2 of the alkyleneoxy groups [-(A ^3a O)-] and [-(A ^3b O)-] may each be 0 or more, and may be selected from a range of about 0 to 15, for example. Preferred ranges are 0 to 10, 0 to 8, 0 to 6, 0 to 4, 0 to 2, and 0 to 1, in the following stepwise order. Furthermore, when the repeat numbers r1 and r2 are 1 or more, the polymerization reactivity is easily improved, and they may be selected from a range of about 1 to 15, for example. Preferred ranges are 1 to 10, 1 to 8, 1 to 6, 1 to 4, 1 to 3, and 1 to 2, in the following stepwise order, and 1 is particularly preferred. In this specification and claims, the "repeat number (number of added moles)" may be an average value (arithmetic mean value, arithmetic mean value) or an average number of added moles, and the preferred embodiment may be the same as the preferred integer range described above. If r1 and r2 are too large, the heat resistance and refractive index may be reduced. In addition, r1 and r2 may be the same or different. When r1 and r2 are 2 or more, the types of the two or more alkyleneoxy groups [-(A ^3a O)-] and [-(A ^3b O)-] may be different from each other, but are preferably the same. In addition, the types of A ^3a and A ^3b may be the same or different from each other.

The positions of substitution of the groups [-O-(A ^3a O) _r1 -] and [-O-(A ^3b O) _r2 -] (i.e., the ether bond forming the main chain) on the rings Z ¹ and Z ² are not particularly limited as long as they are substituted at appropriate positions on Z ¹ and Z ^2. When Z 1 and Z 2 are benzene rings, the positions of substitution of the groups [-O-(A ^3a O) _r1 -] and [-O-(A ^3b O) _r2 -] on the rings Z ^{1 and} Z ² are preferably any one of ^the 2-, 3- or 4-positions, among which the 3- or 4-position, and particularly the 4-position, of the phenyl group bonded to the 9-position of the fluorene ring. Furthermore, when Z ¹ and Z ² are naphthalene rings, they are often substituted at any one of the 5- to 8-positions of the naphthyl group bonded to the 9-position of the fluorene ring, and for example, the 1- or 2-position of the naphthalene ring is substituted with respect to the 9-position of the fluorene ring (substitution in a 1-naphthyl or 2-naphthyl relationship), and it is preferable that the substitution is in a 1,5-position or 2,6-position relationship, particularly 2,6-position relationship, with respect to this substitution position. Furthermore, when Z ¹ and Z ² are ring assembly arene rings, the substitution positions of the groups [-O-(A ^3a O) _r1 -] and [-O-(A ^3b O) _r2 -] are not particularly limited, and for example, they may be substituted on the arene ring bonded to the 9-position of the fluorene or on the arene ring adjacent to this arene ring. For example, when Z ¹ and Z ² are biphenyl rings (or Z ¹ and Z ² are benzene rings, q1 and q2 are 1, and R ^6a and R ^6b 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, and when the 3-position of the biphenyl ring is bonded to the 9-position of the fluorene, the substitution position of the group [-O-(A ^3a O) _r1 -] or [-O-(A ^3b O) _r2 -] may be, for example, any of 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 (B2) include 9,9-bis(hydroxyaryl)fluorenes in which r1 and r2 are 0 in the above formula (4); and 9,9-bis[hydroxy(poly)alkoxyaryl]fluorenes in which r1 and r2 are 1 or more, for example, about 1 to 10. In this specification and claims, unless otherwise specified, "(poly)alkoxy" is used to mean both an alkoxy group and a polyalkoxy group.

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, 9,9-bis(4-hydroxy-3-isopropylphenyl)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-(2-hydroxyethoxy)ethoxy)phenyl]fluorene, and 9,9-bis[4-(2-hydroxypropoxy)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-(2-hydroxyethoxy)ethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]fluorene, and 9,9-bis[4-(2-hydroxypropoxy)-3-methylphenyl]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-(2-hydroxyethoxy)ethoxy)-3- _phenylphenyl ]fluorene, and 9,9-bis(4-( _2- hydroxypropoxy)-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[5-(2-hydroxyethoxy)-1-naphthyl]fluorene, 9,9-bis[6-(2-(2-hydroxyethoxy)ethoxy)-2-naphthyl]fluorene, and 9,9-bis[6-( _{2-hydroxypropoxy)-2} -naphthyl]fluorene.

These second diol units (B2) may be contained alone or in combination of two or more kinds. Preferred second diol units (B2) are 9,9-bis[hydroxy(poly) _alkoxyaryl ]fluorenes such as 9,9-bis[hydroxy(mono- to penta) _{C2-4alkoxyC6-10aryl} ]fluorene, more preferably 9,9-bis[hydroxyC2-4alkoxyC6-10aryl]fluorene-derived structural units. Among them, _9,9 -bis[hydroxyC2-4alkoxyC6-10aryl]fluorene such as 9,9-bis[4-( ₂ -hydroxyethoxy)phenyl]fluorene is preferred from the viewpoint of achieving a good balance between heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) and further improving the refractive index and heat resistance in particular. A structural unit derived from a 9,9-bis[hydroxy C _2-3 alkoxy-phenyl]fluorene is more preferred, and a structural unit derived from a 9,9-bis[hydroxy C 2-3 alkoxy-naphthyl]fluorene such as 9,9-bis[6-(2-hydroxyethoxy)-2 _- naphthyl]fluorene is even more preferred, since it can more effectively reduce birefringence and greatly improve heat resistance while satisfying high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) in a well-balanced manner.

Third Diol Unit (B3)
The diol unit (B) may or may not contain a third diol unit (B3) represented by the following formula (5) as necessary. When the diol unit (B3) is contained, not only is the balance between high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) particularly excellent, but also an excessive increase in glass transition temperature can be suppressed to achieve both heat resistance and moldability, which is preferable.

(In the formula, ^A4 represents a direct bond (single bond) or an alkylene group,
^A5a and ^A5b each represent a linear or branched alkylene group; s1 and s2 each independently represent 0 or an integer of 1 or more;
R ^7a and R ^7b each independently represent a substituent, and t1 and t2 each independently represent an integer of 0 to 6).

In the formula (5), examples of the alkylene group represented by ^A4 include linear or branched _C1-4 alkylene groups such as a methylene group, an ethylene group, a propylene group, a trimethylene group, a 1,2-butanediyl group, a tetramethylene group, etc. Preferred examples of ^A4 are, from the viewpoint of optical properties such as a high refractive index, a low Abbe number, and a low birefringence, a direct bond or a _C1-2 alkylene group such as a methylene group, and a direct bond (single bond) is particularly preferred.

The alkylene group represented by A ^5a and A ^5b is, for example, the same as the alkylene group A ^3a and A ^3b exemplified in the above formula (4), including preferred embodiments thereof.

The repeat numbers s1 and s2 of the alkyleneoxy groups [-(A ^5a O)-] and [-(A ^5b O)-] may be 0 or more, and may be selected from a range of, for example, about 0 to 15, with preferred ranges being 0 to 10, 0 to 8, 0 to 6, 0 to 4, 0 to 2, and 0 to 1, in the following stepwise order. The repeat numbers s1 and s2 are preferably 1 or more, in view of high polymerization reactivity, excellent optical properties such as high refractive index, low Abbe number, and low birefringence, and excellent heat resistance, and furthermore, suppression of coloring, and preferred ranges are 1 to 15, 1 to 10, 1 to 8, 1 to 6, 1 to 4, 1 to 3, and 1 to 2, in the following stepwise order, and particularly preferably 1. The repeat numbers s1 and s2 may be the average number of moles added, and preferred embodiments are the same as the preferred integer ranges described above. If the repeat numbers s1 and s2 are too large, there is a risk of a decrease in heat resistance and refractive index. In addition, s1 and s2 may be the same or different. When s1 and s2 are 2 or more, the types of the two or more alkyleneoxy groups [-(A ^5a O)-] and [-(A ^5b O)-] may be the same or different. In addition, the types of A ^5a and A ^5b may be different from each other, but are preferably the same.

The substitution positions of the (poly)oxyalkylene groups [-O-(A ^5a O) _s1 -] and [-O-(A ^5b O) _s2 -] forming the main chain of the thermoplastic resin may be any of the 2- to 4-positions relative to the 1-position of the two naphthalene ring skeletons bonded to A ⁴ , with the 2-position being preferred in terms of reducing birefringence. For example, when A ⁴ is a direct bond (single bond), the substitution positions may be any of the 2- to 4-positions or the 2'- to 4'-positions of the 1,1'-binaphthyl skeleton, with the 2,2'-positions being preferred in terms of reducing birefringence.

R ^7a and R ^7b are preferably substituents that are inactive in the polymerization reaction (non-polymerizable groups), and examples thereof include the same groups as those exemplified as the groups R ^2a and R ^2b in the section on formula (1), including preferred embodiments thereof.

The substitution numbers t1 and t2 of R ^7a and R ^7b may be, for example, integers of about 0 to 5, and preferred ranges are, in the following stepwise order, integers of 0 to 4, integers of 0 to 3, integers of 0 to 2, and integers of 0 to 1, preferably 0. t1 and t2 may be the same or different from each other. Furthermore, the types of R ^7a and R ^7b may be the same or different from each other. When t1 and t2 are 2 or more, the types of R ^7a and R ^7b that are 2 or more may be the same or different from each other.

The substitution positions of R ^7a and R ^7b are not particularly limited as long as they are positions other than the substitution positions of A ⁴ and the (poly)oxyalkylene groups [-O-(OA ^5a ) _s1 -] and [-O-(OA ^5b ) _s2 -] in the two naphthalene ring skeletons, and are preferably the 3rd to 8th positions relative to the 1st position of the two naphthalene ring skeletons bonding to A ^4. For example, when A ⁴ is a direct bond (single bond), it is preferably the 3rd to 8th positions or the 3' to 8' positions of the 1,1'-binaphthyl skeleton.

Representative examples of the third diol unit (B3) include units derived from (or corresponding to) a third diol component such as dihydroxy-1,1'-binaphthyls in which ^A4 is a direct bond (single bond). Examples of the dihydroxy-1,1'-binaphthyls include dihydroxy-1,1'-binaphthyls such as 2,2'-dihydroxy-1,1'-binaphthyl;bis[hydroxy(poly)alkoxy]-1,1'-binaphthyl; and the like.

Examples of bis[hydroxy(poly)alkoxy]-1,1'-binaphthyl include 2,2'-bis[hydroxy(mono- to deca)C _2-4 alkoxy]-1,1'-binaphthyl such as 2,2'-bis(2-hydroxyethoxy)-1,1'-binaphthyl, 2,2'-bis(2-hydroxypropoxy)-1,1'-binaphthyl, and 2,2'-bis[2-(2-hydroxyethoxy)ethoxy]-1,1'-binaphthyl.

These third diol units (B3) may be contained alone or in combination of two or more. Among these third diol units (B3), from the viewpoints of not only polymerization reactivity but also excellent optical properties such as a high refractive index, a low Abbe number, and a low birefringence, heat resistance, and suppression of coloration, 2,2'-bis[hydroxy(mono- to deca)C _2-4 alkoxy]-1,1'-binaphthyl is preferred, among which 2,2'-bis[hydroxy(mono- to hexa)C 2-4 alkoxy]-1,1'-binaphthyl is more preferred, and 2,2'-bis[hydroxy(mono- to tri)C _2-3 alkoxy]-1,1'-binaphthyl is particularly preferred, and a structural unit derived from 2,2'-bis[hydroxy(mono- to tri)C _2-3 alkoxy]-1,1'-binaphthyl such as 2,2'-bis(2 _- hydroxyethoxy)-1,1'-binaphthyl is particularly preferred.

Fourth Diol Unit (B4)
The diol unit (B) may not necessarily be contained, but may or may not contain a fourth diol unit (B4) different from the first diol unit (B1), the second diol unit (B2) and the third diol unit (B3) as necessary.

Examples of the fourth diol unit (B4) include alicyclic diols, aromatic diols (excluding the second diol unit (B2) and the third diol unit (B3)), and structural units derived from alkylene oxide (or alkylene carbonate, 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 (or corresponding alkylene carbonate, 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 bisphenol A.

The diol unit (B) may contain these fourth diol units (B4) alone or in combination of two or more.

The total proportion of the first diol unit (B1), the second diol unit (B2) and the third diol unit (B3) can be selected from a range of, for example, 1 mol% or more, specifically about 10 to 100 mol%, based on the total diol unit (B). Preferred ranges are 30 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, 95 mol% or more in the following stepwise order, and it is particularly preferred that the total is 100 mol%, substantially free of the fourth diol unit (B4).

The ratio of the first diol unit (B1) is, for example, about 1 mol% or more, preferably 5 to 100 mol%, based on the total diol unit (B). In order to lower the Abbe number and greatly improve heat resistance, it may be about 50 to 100 mol%, and the preferred ranges are 70 to 100 mol%, 90 to 100 mol%, 95 to 100 mol%, and particularly 100 mol%, in the following stepwise order. On the other hand, in order to further improve high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) while maintaining a good balance when combined with the second diol unit (B2) and/or the third diol unit (B3), the ratio of the first diol unit (B1) may be, for example, 1 to 50 mol%, based on the total diol unit (B), and the preferred ranges are 3 to 45 mol%, 5 to 40 mol%, 8 to 35 mol%, and 10 to 30 mol%, in the following stepwise order.

The ratio of the first diol unit (B1) to the second diol unit (B2) (hereinafter also referred to as B1/B2) may be selected, for example, from a range of about B1/B2 (molar ratio) = 1/99 to 100/0, and preferred ranges are 5/95 to 50/50, 8/92 to 40/60, and 10/90 to 35/65 in the following stepwise order. If the ratio of the first diol unit (B1) is too small, the polymerization reactivity and moldability (productivity) may decrease, while if the ratio of the second diol unit (B2) is too small, the heat resistance may not be sufficiently improved, and the composition may not be usable in applications requiring durability in high-temperature environments, such as in-vehicle lenses. In particular, when ^Z1 and ^Z2 in the formula (4) contain a second diol unit (B2) which is a condensed polycyclic aromatic hydrocarbon ring such as a naphthalene ring, the B1/B2 (molar ratio) may be selected from a range of about 1/99 to 30/70, and preferred ranges are 5/95 to 25/75, 8/92 to 20/80, and 10/90 to 15/85 in the following stepwise order. With such a ratio, it appears that it is possible to further improve the refractive index and heat resistance in particular while satisfying high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) in a well-balanced manner. On the other hand, when Z ¹ and Z ² in the formula (4) contain a second diol unit (B2) that is a benzene ring (monocyclic aromatic hydrocarbon ring), the B1/B2 (molar ratio) may be selected from a range of about 5/95 to 50/50, and preferred ranges are 10/90 to 45/55, 20/80 to 40/60, and 25/75 to 35/65 in the following stepwise order, and in applications where low birefringence is important, it is preferably 10/90 to 40/60, and more preferably 15/85 to 35/75. With such a ratio, it appears that birefringence in particular can be more effectively reduced and heat resistance can be greatly improved while high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) are well balanced.

The ratio of the first diol unit (B1) to the third diol unit (B3) (hereinafter also referred to as B1/B3) may be selected, for example, from a range of about B1/B3 (molar ratio) = 1/99 to 100/0, and preferred ranges are 5/95 to 50/50, 10/90 to 40/60, 15/85 to 35/65, and 20/80 to 30/70 in the following stepwise order. If the ratio of the first diol unit (B1) is too low, the polymerization reactivity and moldability (productivity) may decrease, while if the ratio of the third diol unit (B3) is too low, not only is it difficult to improve high heat resistance and optical properties (low Abbe number, high refractive index, and low birefringence) in a balanced manner, but it may also be difficult to suppress an excessive increase in the glass transition temperature and achieve both heat resistance and moldability.

The thermoplastic resin may or may not contain other structural units (C) different from the dicarboxylic acid units (A) and the diol units (B) as necessary, provided that the effects of the present invention are not impaired. Examples of other structural units (C) include structural units derived from hydroxyalkanoic acids and lactones, polyfunctional polymerization components having three or more polymerizable groups (carboxyl groups and/or hydroxyl groups), carbonate bond-forming components, etc.

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

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

The carbonate bond forming component may be any compound capable of forming a carbonate bond by reacting with two diol components. In other words, the constituent unit derived from the carbonate bond forming component means a carbonyl group [-C(=O)-], and forms a carbonate bond together with the terminal oxygen atoms of the two diol units bonded adjacent to this carbonyl group. Representative carbonate bond forming components include, for example, phosgenes such as phosgene and triphosgene, and carbonate diesters such as diphenyl carbonate.

The proportion of such other structural units (C) is, for example, 50 mol% or less relative to the total amount of structural units (total amount of dicarboxylic acid units (A), diol units (B) and other structural units (C)), and preferred ranges are 0-30 mol%, 0-15 mol%, 0-10 mol%, 0.01-1 mol% in the following stepwise order, and it is preferable that the other structural units (C) are not substantially contained.

[Production method]
(Method for Producing the First Dicarboxylic Acid Component)
The first dicarboxylic acid component may be a commercially available product, but the first dicarboxylic acid component represented by the following formula (1A) is a novel compound and may be prepared, for example, according to the following reaction scheme.

(In the formula, R ^1a and R ^1b each independently represent a C _1-5 alkoxy group,
R ^3a and R ^3b each independently represent a C _1-5 alkoxy group;
R ^2a and R ^2b , k1 and k2 are the same as those in formula (1) above, including preferred embodiments.

In the above reaction scheme, 6-hydroxy-2-naphthoic acids (or 2-hydroxy-6-naphthoic acids) are used and reacted in the following order: esterification reaction, coupling reaction (oxidative coupling reaction), and etherification reaction to prepare the dicarboxylic acid component represented by formula (1A).

(i) Esterification Reaction of 6-hydroxy-2-naphthoic Acids In the esterification reaction, 6-hydroxy-2-naphthoic acids are reacted with alcohols corresponding to the alkoxy groups represented by R ^3a and R ^3b to synthesize 6-hydroxy-2-naphthoic acid esters.

Examples of the 6-hydroxy-2-naphthoic acid include 6-hydroxy-2-naphthoic acid which may have a substituent represented by R ^2a and R ^2b described in the formula (1) above, and 6-hydroxy-2-naphthoic acid is preferred. Note that R ^2a and R ^2b , as well as k1 and k2, are each preferably the same as each other, that is, it is preferred to use one type of 6-hydroxy-2-naphthoic acid.

Examples of alcohols corresponding to the alkoxy groups R ^3a and R ^3b include linear or branched C _1-5 alcohols such as methanol, _ethanol , isopropanol, etc., preferably linear or branched C 1-3 alcohols, more preferably C _1-2 alcohols such as methanol, etc. It is preferable that R ^3a and R ^3b are the same, that is, one type of alcohol is used.

The proportion of the alcohols used is, for example, 50 to 500 parts by mass, preferably 100 to 400 parts by mass, and more preferably 200 to 300 parts by mass, per 100 parts by mass of 6-hydroxy-2-naphthoic acids.

The esterification reaction may be carried out in the presence of a conventional esterification catalyst. Examples of the esterification catalyst include acid catalysts, base catalysts, and metal catalysts such as metal alkoxides, specifically titanium (IV) alkoxides such as titanium (IV) tetraisopropoxide. Of these catalysts, acid catalysts are preferably used.

The acid catalyst is not particularly limited, and examples thereof include inorganic acids; organic acids; Lewis acids such as boron trifluoride etherate and tin tetrachloride; and solid acid catalysts such as cation exchange resins. These acid catalysts may be used alone or in combination of two or more. These acid catalysts may also be hydrates.

Examples of the inorganic acid include strong acids, specifically sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, etc.; and homo- or heteropoly acids, specifically tungstophosphoric acid, molybdophosphoric acid, tungstosilicic acid, molybdosilicic acid, etc.

Examples of the organic acid include sulfonic acids, specifically, alkanesulfonic acids such as methanesulfonic acid and ethanesulfonic acid, fluorinated alkanesulfonic acids such as trifluoromethanesulfonic acid, and arenesulfonic acids such as p-toluenesulfonic acid. As the acid catalyst, inorganic acids, for example, sulfuric acid such as concentrated sulfuric acid, are often used.

The proportion of the esterification catalyst used is, for example, 5 to 50 parts by mass, preferably 10 to 40 parts by mass, and more preferably 20 to 30 parts by mass, per 100 parts by mass of 6-hydroxy-2-naphthoic acids.

The reaction temperature is, for example, 50 to 150°C, preferably 60 to 100°C. The reaction may be carried out at reflux temperature. The reaction time may be, for example, about 1 to 24 hours.

The reaction can be carried out in air or in an inert atmosphere such as nitrogen gas or a rare gas with stirring, and may be carried out under normal pressure, elevated pressure, or reduced pressure.

After the reaction is completed, the 6-hydroxy-2-naphthoic acid esters produced may be separated and purified by conventional methods, such as neutralization, washing, dehydration, filtration, adsorption, concentration, extraction, crystallization, reprecipitation, centrifugation, column chromatography, or a combination of these methods.

(ii) Oxidative Coupling Reaction of 6-Hydroxy-2-naphthoic Acid Esters In the coupling reaction, 6-hydroxy-2-naphthoic acid esters obtained in the above-mentioned esterification reaction are used to synthesize 6,6'-bis(alkoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyls.

As described above, R ^2a and R ^2b , k1 and k2, and R ^3a and R ^3b are preferably the same as each other, and the 6-hydroxy-2-naphthoic acid ester used in the coupling reaction is preferably one type of compound (the same compound).

The coupling reaction is often carried out in the presence of a catalyst, and examples of the catalyst include copper salts. Examples of copper salts include copper halides such as copper chloride (I), copper chloride (II), copper bromide (I), copper bromide (II), and copper iodide (I); and copper carboxylates such as copper formate (II) and copper acetate (II). These catalysts can be used alone or in combination of two or more. Of these catalysts, copper halides are preferred, copper halides (I) are more preferred, and copper chloride (I) is particularly preferred.

The ratio of catalyst may be, for example, about 0.005 to 1 mole per mole of 6-hydroxy-2-naphthoic acid esters, and the preferred ranges are 0.01 to 0.8 moles, 0.05 to 0.6 moles, 0.1 to 0.5 moles, 0.2 to 0.4 moles, 0.25 to 0.35 moles, and 0.27 to 0.33 moles in the following stepwise order.

The reaction may be carried out in the presence of a solvent. The solvent is preferably a polar solvent having a nitrogen atom, such as amides, ureas, anilines, morpholines, and pyridines.

Examples of amides include N,N-substituted amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylpropioamide, N-methylacetanilide, and N-methyl-2-pyrrolidone.

Examples of ureas include tetraalkylureas such as tetramethylurea and tetraethylurea.

Examples of anilines include N,N-substituted anilines such as N,N-dimethylaniline and N,N-dimethyl-methoxyaniline.

Examples of morpholines include morpholine and N-methylmorpholine.

Examples of pyridines include pyridine and 2-methylpyridine.

These solvents can be used alone or in combination of two or more. Among these solvents, amides such as N,N-dimethylformamide are preferred in terms of solubility.

The proportion of the solvent used is not particularly limited and may be, for example, about 10 to 5,000 parts by mass per 100 parts by mass of the 6-hydroxy-2-naphthoic acid esters. Preferred ranges are 15 to 3,000 parts by mass, 20 to 1,000 parts by mass, 30 to 500 parts by mass, 50 to 150 parts by mass, 70 to 130 parts by mass, 80 to 120 parts by mass, and 90 to 110 parts by mass, in the following stepwise order.

The reaction temperature is, for example, 40 to 120°C, preferably 60 to 80°C. The reaction time may be, for example, about 1 to 48 hours, preferably 12 to 36 hours.

The reaction can be carried out in air or in an inert atmosphere such as nitrogen gas or a rare gas with stirring, and may be carried out under normal pressure, pressure, or reduced pressure. When copper(I) chloride is used as the catalyst, it is preferable to carry out the reaction while bubbling air or oxygen gas at, for example, 1 to 20 L/min, preferably 2 to 10 L/min, since the catalytic activity is regenerated by the oxygen, allowing the amount of catalyst to be reduced.

After the reaction is completed, the resulting 6,6'-bis(alkoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyls may be separated and purified by conventional methods, such as neutralization, washing, dehydration, filtration, adsorption, concentration, extraction, crystallization, reprecipitation, centrifugation, column chromatography, or a combination of these methods.

(iii) 6,6'-bis(alkoxycarbonyl)-2,2'-dihydroxy-1,1
In the etherification reaction, 6,6'-bis(alkoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyls are reacted with an etherifying agent corresponding to the alkoxy groups R ^1a and R ^1b to etherify the hydroxyl groups at the 2- and 2-positions of the 1,1'-binaphthyl skeleton.

Examples of the etherifying agent corresponding to the alkoxy groups R ^1a and R ^1b include alkyl halides, dialkyl sulfates, etc. Examples of the alkyl halides include alkyl iodides, alkyl bromides, alkyl chlorides, etc., and preferably C _1-5 alkyl iodides such as methyl iodide. Examples of the dialkyl sulfates include C _1-5 alkyl sulfates such as dimethyl sulfate, etc.

These etherifying agents can be used alone or in combination of two or more. Among these alkylating agents, alkyl halides are preferred, and C _1-5 alkyl iodides such as methyl iodide are more preferred. Since the alkoxy groups R ^1a and R ^1b are preferably the same, the corresponding etherifying agents are also preferably one type of compound (the same compound).

The proportion of the etherification agent used may be, for example, about 2 to 10 moles per mole of 6,6'-bis(alkoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyls, and the preferred ranges are 2.1 to 8 moles, 2.2 to 5 moles, 2.3 to 4 moles, 2.5 to 3.5 moles, 2.7 to 3.3 moles, and 2.8 to 3.2 moles, in the following stepwise order.

The etherification reaction may be carried out in the presence of a base, and examples of the base include metal hydroxides, metal carbonates, and metal hydrogen carbonates. Examples of the metal hydroxides include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. Examples of the metal carbonates include alkali metal carbonates such as sodium carbonate and potassium carbonate. Examples of the metal hydrogen carbonates include alkali metal hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate.

These bases can be used alone or in combination of two or more. Of these bases, metal carbonates are preferred, and alkali metal carbonates such as potassium carbonate are more preferred.

The ratio of the base may be, for example, about 2 to 10 moles per mole of 6,6'-bis(alkoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyls, and the preferred ranges are 2.1 to 8 moles, 2.2 to 6 moles, 2.3 to 5 moles, 2.5 to 4 moles, 2.7 to 3.8 moles, 3 to 3.6 moles, and 3.2 to 3.4 moles in the following stepwise order.

The reaction may be carried out in the presence of a solvent, and examples of the solvent include nitriles such as acetonitrile; amides such as N,N-dimethylformamide, N,N-diethylformamide, and N,N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide; and hydrocarbons, specifically, aliphatic or alicyclic hydrocarbons such as hexane, and aromatic hydrocarbons such as benzene and toluene.

These solvents can be used alone or in combination of two or more. Of these solvents, amides such as N,N-dimethylformamide are preferred. The proportion of the solvent used is not particularly limited, and may be, for example, about 10 to 5000 parts by mass per 100 parts by mass of 6,6'-bis(alkoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyls, with preferred ranges being 50 to 3000 parts by mass, 80 to 2000 parts by mass, 100 to 1000 parts by mass, 200 to 800 parts by mass, 300 to 700 parts by mass, 400 to 600 parts by mass, and 450 to 550 parts by mass, in the following stepwise order.

The reaction temperature is, for example, 40 to 120°C, preferably 60 to 80°C. The reaction time may be, for example, about 1 to 48 hours, preferably 12 to 36 hours.

The reaction can be carried out in air or in an inert atmosphere such as nitrogen gas or a rare gas with stirring, and may be carried out under normal pressure, pressure, or reduced pressure. When copper(I) chloride is used as the catalyst, it is preferable to carry out the reaction while bubbling air or oxygen gas at, for example, 1 to 20 L/min, preferably 2 to 10 L/min, since the catalytic activity is regenerated by the oxygen, allowing the amount of catalyst to be reduced.

After the reaction is completed, the resulting 6,6'-bis(alkoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyls may be separated and purified by conventional methods, such as neutralization, washing, dehydration, filtration, adsorption, concentration, extraction, crystallization, reprecipitation, centrifugation, column chromatography, or a combination of these methods.

(Polycondensation of Thermoplastic Resin)
The method for producing the thermoplastic resin is not particularly limited except that the dicarboxylic acid component (A) containing the first dicarboxylic acid component (A1) is used as a polymerization component, and a conventional method can be used depending on the type of resin and other polymerization components (copolymerization components). For example, in the case of a polyester resin such as a polyester resin, the dicarboxylic acid component (A) corresponding to each of the above-mentioned dicarboxylic acid units and the diol component (B) corresponding to the above-mentioned diol units can be reacted to produce the thermoplastic resin, and the thermoplastic resin can be prepared by a conventional method, specifically, 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 dicarboxylic acid component (A) to diol component (B) used (or the ratio of diol used) is usually, for example, 1/1.2 to 1/0.8, preferably 1/1.1 to 1/0.9 (molar ratio), but this range is not necessarily required. At least one component selected from each dicarboxylic acid component (A) and each diol component (B) may be used in excess of the planned introduction ratio. For example, the first diol component (B1), such as ethylene glycol, which can be distilled from the reaction system, may be used in excess of the ratio (or the introduction ratio) introduced into the polyester 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, alkoxide; organic acid salt such as acetate, propionate; inorganic acid salt such as borate, carbonate; metal 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 such stabilizers include phosphorus compounds such as trimethyl phosphate, triethyl phosphate, triphenyl phosphate, dibutyl phosphate (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 250 to 310° C., and more preferably 280 to 300° C.

[Characteristics and uses of thermoplastic resins]
(Characteristics)
Since the thermoplastic resin contains the first dicarboxylic acid unit (A1), the refractive index can be improved without excessively increasing the low birefringence, and in particular, the Abbe number can be significantly reduced and the heat resistance is excellent, compared to a thermoplastic resin formed using a dicarboxylic acid component having a conventional 1,1'-binaphthyl skeleton, for example, a dicarboxylic acid component having a carboxyl group at the 2,2'-position via a methoxy group or the like. That is, a high refractive index and a low birefringence, which are usually in a trade-off relationship, can be simultaneously achieved, and the optical properties (low Abbe number, high refractive index, low birefringence) and heat resistance can be improved in a well-balanced manner.

The refractive index nD of the thermoplastic resin can be selected, for example, from a range of about 1.6 to 1.75 at a temperature of 20°C and a wavelength of 589 nm, and is preferably in the following stepwise order: 1.64 to 1.72, 1.66 to 1.71, 1.665 to 1.7, 1.67 to 1.695, 1.675 to 1.69, and more preferably 1.68 to 1.685.

The Abbe number of the thermoplastic resin is, for example, 19 or less at a temperature of 20°C, and the preferred ranges are 18.5 or less, 18 or less, 17.5 or less, and 17 or less in the following stepwise order. As described above, since the thermoplastic resin can effectively reduce the Abbe number, it can be effectively used in applications where a low Abbe number is required, such as optical components in various cameras, such as 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 (blurring) that occurs in the convex lens, and is usually composed of a combination of multiple concave and convex lenses, and the thermoplastic resin can fully meet the low Abbe number required for the concave lens. The lower limit of the Abbe number may be, for example, 15 or more, 15.5 or more, 16 or more, or 16.5 or more.

The birefringence of a thermoplastic resin may be evaluated by the birefringence (triple birefringence) of a stretched film obtained by uniaxially stretching a film formed from a thermoplastic 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 triple birefringence of the stretched film can be selected from a range of, for example, 75×10 ⁻⁴ or less at a measurement temperature of 20°C and a wavelength of 600 nm, and the preferred ranges are 60×10 ⁻⁴ or less, 50×10 ⁻⁴ or less, 40×10 ⁻⁴ or less, 30×10 ⁻⁴ or less, 25×10 ⁻⁴ or less, 20×10 ⁻⁴ or less, 15×10 ⁻⁴ or less, and 10×10 ⁻⁴ or less in the following stepwise manner. The lower limit of the absolute value of the triple birefringence may be, for example, 0 or more, or 0.1×10 ⁻⁴ or more.

The glass transition temperature Tg of the thermoplastic resin can be selected, for example, from a range of about 120 to 280 ° C., and the preferred ranges are 150 to 250 ° C., 160 to 240 ° C., 170 to 230 ° C., 180 to 220 ° C., 185 to 215 ° C., 190 to 210 ° C., and more preferably 195 to 205 ° C. If the glass transition temperature Tg is too low, the heat resistance decreases, and the resin may be easily discolored (or stained) during production and/or use, or may deform in a high-temperature environment after being molded into a specified shape. Therefore, it may not be usable in applications requiring high heat resistance or thermal stability, such as optical lenses for automobiles. In addition, if the glass transition temperature Tg is too high, the moldability decreases, and it may be difficult to form a smooth surface of a molded body such as an optical lens when molding the molded body by a method such as injection molding. Therefore, from the viewpoint of achieving both high heat resistance and high moldability, the glass transition temperature Tg is preferably 150 to 170°C, and more preferably 160 to 170°C.

Although thermoplastic resins have a rigid and bulky binaphthyl skeleton, they unexpectedly have high polymerization reactivity and therefore excellent moldability (productivity). The weight-average molecular weight Mw of polyester resins 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 polystyrene equivalent, with preferred ranges being 15,000 to 150,000, 20,000 to 100,000, preferably 25,000 to 80,000, 30,000 to 70,000, 40,000 to 65,000, and 50,000 to 60,000, in the following stepwise order. If the weight-average molecular weight Mw is too low, moldability (productivity) may be easily reduced.

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

(Molded body)
The molded article contains at least the thermoplastic resin and has excellent optical properties (low Abbe number, high refractive index, low birefringence, etc.) and heat resistance, and can be used as an optical member such as an optical film (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, 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, thermoplastic resins are useful for forming optical films because they have a variety of excellent optical properties. Therefore, the present invention also includes films (optical films or optical sheets) formed from the thermoplastic resins.

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 thermoplastic resin using a conventional film-forming method, such as a casting method (solvent casting method), a melt extrusion method, or a calendar method.

The film may be unstretched or stretched, and even stretched films can maintain low birefringence. Such stretched films may be either uniaxially stretched or biaxially stretched.

The stretching ratio in each direction in uniaxial or biaxial stretching is, for example, 1.1 to 10 times, preferably 1.2 to 8 times, and more preferably 1.5 to 6 times. In the case of biaxial stretching, it may be equal stretching, for example, 1.5 to 5 times stretching in both the longitudinal and transverse directions, or uneven stretching, for example, 1.1 to 4 times stretching in the longitudinal direction and 2 to 6 times stretching in the transverse direction. In the case of uniaxial stretching, it may be longitudinal stretching, for example, 2.5 to 8 times stretching in the longitudinal direction, and transverse stretching, for example, 1.2 to 5 times stretching 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 the wet stretching method or the dry stretching method may be used, and in the case of biaxial stretching, either the tenter method (flat method) or the tube method may be used, with the tenter method being preferred because of its excellent uniformity in stretched thickness.

[Abbe number reducer]
The Abbe number reducing agent is represented by the following formula (1B).

(In the formula, R ^3a and R ^3b each independently represent a hydroxyl group, an alkoxy group, or a halogen atom,
R ^1a and R ^1b , R ^2a and R ^2b , k1 and k2 are the same as those in formula (1), including preferred embodiments.

Examples of the alkoxy groups of R ^3a and R ^3b include C _1-5 alkoxy groups such as methoxy, ethoxy, and t-butoxy, and examples of the halogen atom include chlorine and bromine. The bonding positions of the group [-C(=O)-R ^3a ] and the group [-C(=O)-R ^3b ] are the same as the bonding positions of the two carbonyl groups [-C(=O)-] in the above formula (1), including preferred embodiments.

The Abbe number reducer is suitable for use as an Abbe number reducer for resins, particularly thermoplastic resins, and when blended with a thermoplastic resin, it can not only reduce the Abbe number of the thermoplastic resin, but also improve the refractive index and moldability of the thermoplastic resin.

Examples of thermoplastic resins 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.

These thermoplastic resins can be used alone or in combination. Of these, cyclic olefin resins, polymethyl methacrylate resins, polyester resins, and polycarbonate resins are preferred, with cyclic olefin resins being particularly preferred.

The proportion of the Abbe number reducer is, for example, 0.1 to 100 parts by mass, preferably 1 to 50 parts by mass, more preferably 3 to 30 parts by mass, and even more preferably 5 to 20 parts by mass, relative to 100 parts by mass of the thermoplastic resin.

The molded article formed from the resin composition containing the Abbe number reducer and the thermoplastic resin is similar to the molded article formed from the thermoplastic resin containing the dicarboxylic acid unit (A) in terms of the conventional additives contained in the molded article, the molding method, and the shape, including preferred embodiments.

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 items and raw materials are shown below.

[Evaluation method]
(HPLC)
The HPLC (high performance or high performance liquid chromatograph) was performed using a Shimadzu Corporation "LC-2010CHT" apparatus and a Tosoh Corporation "ODS-80TM" column, dissolving the sample in acetonitrile, and the HPLC purity [area %] was calculated. The detailed measurement conditions are shown in Table 1.

( ^1H -NMR)
The sample was dissolved in deuterated chloroform 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).

For the resin samples, the integral values of the peaks derived from each monomer used in the polymerization were calculated based on the obtained spectrum, and the proportion of each monomer component (structural unit) introduced into the polymer (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 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 polystyrene was determined using gel permeation chromatography ("HLC-8320GPC" manufactured by Tosoh Corporation).

(Refractive index nD)
The sample was heat-pressed at 200 to 240° C. to form a film having a thickness of 200 to 300 μm. This film was cut into a rectangular shape having a length of 20 to 30 mm and a width of 10 mm to obtain a test piece. The refractive index nD of the obtained test piece at 589 nm (D line) was measured using a multi-wavelength Abbe refractometer (manufactured by Atago Co., Ltd., "DR-M4 (circulating thermostatic bath 60-C3)") at a measurement temperature of 20° C. and using diiodomethane as a 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 (stretched 3 times))
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 × 50 mm, and uniaxially stretched at a stretch ratio of 3 times at 25 mm / min under a temperature condition of glass transition temperature Tg + 10 ° C. to obtain a test piece. The retardation of the obtained test piece was measured by a parallel Nicol rotation method using a phase difference 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 triple birefringence).

(Melt Flow Rate MFR)
In accordance with JIS K7210, the measurement was performed under conditions of a temperature of 280° C. and a load of 16 kg in Comparative Example 1. In Comparative Example 2 and Example 17, the measurement was performed under conditions of a temperature of 280° C. and a load of 2.16 kg.

[Raw materials]
(Dicarboxylic acid component)
BNAC-E: 2,2'-bis(ethoxycarbonylmethoxy)-1,1'-binaphthyl, synthesized according to Synthesis Example 4 described in JP2018-59074A 2,3-BMN-m: 3,3'-bis(methoxycarbonyl)-2,2'-dimethoxy-1,1'-binaphthyl, synthesized according to Synthesis Example 1 described below 2,6-BMN-m: 6,6'-bis(methoxycarbonyl)-2,2'-dimethoxy-1,1'-binaphthyl, synthesized according to Example 1 described below FDP-m: 9,9-bis(2-methoxycarbonylethyl)fluorene [or 9,9-bis(2-carboxyethyl)fluorene or dimethyl ester of fluorene-9,9-dipropionic acid], synthesized in the same manner as in Example 1 of JP-A-2005-89422, except that methyl acrylate [37.9 g (0.44 mol)] was used instead of t-butyl acrylate. 2-DNFDP-m: 9,9-bis(2-methoxycarbonylethyl)-2,7-di(2-naphthyl)fluorene, synthesized according to Example 1B of WO2020-213470. DDA-m: dimethyl 1,12-dodecanedioate. DMT: dimethyl terephthalate.

(Carbonate bond forming components)
DPC: diphenyl carbonate

(Diol component)
BPEF: 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, manufactured by Osaka Gas Chemicals Co., Ltd. BNEF: 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene, synthesized according to Synthesis Example 1 described in JP-A-2018-59074 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 1,5-PDO: 1,5-pentanediol

[Synthesis Example 1] Preparation of 2,3-BMN-m While mixing and stirring 3-hydroxy-2-naphthoic acid (14.0 kg, 74.4 mol) and methanol (36.3 kg), concentrated sulfuric acid (3.65 kg, 36.5 mol) was added dropwise so that the temperature of the reaction solution (mixture) was 20 ° C. or less, and the mixture was reacted while refluxing and dehydrating for 21 hours, and then methanol was distilled off under reduced pressure. Methyl isobutyl ketone (hereinafter also referred to as MIBK; 37.0 kg) and ion-exchanged water (14.0 kg) were added (added) to dissolve the reaction mixture, and after performing an analysis operation, the organic layer was washed with water until the pH became 7. The obtained organic layer was concentrated, and then methanol (42.0 kg) was added so that the temperature of the reaction solution (concentrated organic layer) was 50 ° C. or less, and cooling crystallization was performed. After crystals were precipitated at 45 ° C., the mixture was gradually cooled and held at 10 ° C. or less for 1 hour, and the precipitated crystals were filtered. The filtered crystals were rinsed with methanol and then dried under reduced pressure to obtain 12.7 kg of methyl 3-hydroxy-2-naphthoate (yield 84%, HPLC purity 99.6 area %).

Then, the obtained methyl 3-hydroxy-2-naphthoate (12.5 kg, 61.8 mol), N,N-dimethylformamide (12.5 kg), and copper(I) chloride (1.32 kg, 13.3 mol) were dissolved (mixed) at 70°C, and the reaction was carried out at 70°C for 20 hours while bubbling air at a rate of 5 L/min. After confirming the disappearance of the raw materials by HPLC, ion-exchanged water (25.0 kg) was added, and the precipitated crystals were filtered. The filtered crystals were rinsed with ion-exchanged water and then with methanol, and then dried under reduced pressure to obtain 12.4 kg of 3,3'-bis(methoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyl (yield 99%, HPLC purity 99.6 area%).

Next, 12.4 kg of the resulting 3,3'-bis(methoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyl, potassium carbonate (14.1 kg, 102 mol), and N,N-dimethylformamide (26.0 kg) were mixed and stirred, while methyl iodide (13.2 kg, 93.0 mol) was added dropwise so that the temperature of the reaction solution was 20°C or less. After that, the mixture was stirred at 40°C for 12 hours, and after confirming the disappearance of the raw materials by HPLC, MIBK (25.8 kg) and ion-exchanged water (12.9 kg) were charged (added), and unnecessary materials (insoluble materials) were appropriately filtered and washed with water. The organic layer was washed with 1N hydrochloric acid (25.8 kg), ion-exchanged water (12.9 kg), and 0.5% by mass aqueous sodium hydroxide solution (12.9 kg) in that order, and then washed twice with ion-exchanged water (12.9 kg) until the pH of the aqueous layer reached 7. The resulting organic layer was concentrated, and 2-propanol (19.0 kg) was added so that the temperature of the reaction solution (concentrated organic layer) was 80°C or less, and then cooling and crystallization were performed. After confirming crystal precipitation at around 45°C, the mixture was gradually cooled and held at 10°C or less for 1 hour. The precipitated crystals were filtered, rinsed twice with 2-propanol cooled to 10°C or less, and then dried under reduced pressure to obtain 11.8 kg of crystals of 2,3-BMN-m represented by the following formula (yield 89%, HPLC purity 99.7% area%).

[Example 1] Preparation of 2,6-BMN-m 6-Hydroxy-2-naphthoic acid (10.0 kg, 53.1 mol) and dehydrated methanol (26.0 kg) were mixed and stirred, and 98% by mass concentrated sulfuric acid (2.6 kg) was dropped so that the temperature of the reaction solution (mixture) was 25 ° C. or less. The mixture was reacted while refluxing and dehydrating for 10.5 hours, and then methanol was distilled off under reduced pressure. MIBK (42.0 kg) was charged (added) thereto to dissolve the reaction mixture, and the organic layer was washed with water until the pH became 7. The obtained organic layer was concentrated, and then methanol (30.0 kg) was added and dissolved at 75 ° C., followed by cooling and crystallization. After crystals were precipitated at 45 ° C., the mixture was gradually cooled and held at 10 ° C. or less for 1 hour, and the precipitated crystals were filtered. The filtered crystals were rinsed by pouring cold methanol into them, and then dried under reduced pressure at 60° C. to obtain 8.47 kg of methyl 6-hydroxy-2-naphthoate (yield 78.8%, HPLC purity 98.5 area %).

Next, the obtained 6-hydroxy-2-naphthoic acid methyl ester (4.0 kg, 19.8 mol), N,N-dimethylformamide (4.0 kg), and copper(I) chloride (588.0 g, 5.9 mol, added in three portions) were dissolved (mixed) at 70°C, and the reaction was carried out at 70°C for 23.5 hours while bubbling air at a rate of 2 to 10 L/min. After confirming the disappearance of the raw materials by HPLC, ion-exchanged water (4.0 kg) was added, and the precipitated crystals were filtered. The filtered crystals were rinsed (rinsed) at room temperature with ion-exchanged water and then methanol, and the crystals were taken out. After that, a series of operations, that is, the series of operations of adding methanol to the taken out crystals, heating and stirring at 50°C, filtering, and rinsing with 50°C methanol, was carried out multiple times. Then, 1N hydrochloric acid (12.0 kg) was added, stirred at room temperature, and filtered. The resulting crystals were rinsed with ion-exchanged water and then with methanol, and then dried under reduced pressure at 60°C to obtain 2.83 kg of 6,6'-bis(methoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyl (yield 71.1%, HPLC purity 98.1% area%).

Next, the obtained 6,6'-bis(methoxycarbonyl)-2,2'-dihydroxy-1,1'-binaphthyl (1.4 kg, 3.5 mol), potassium carbonate (1.6 kg, 11.5 mol), and dehydrated N,N-dimethylformamide (7.0 kg, added in two portions) were mixed and stirred, while methyl iodide (1.5 kg, 10.4 mol) was added dropwise. After that, the mixture was stirred at 40°C for 6 hours, and after the disappearance of the raw materials was confirmed by HPLC, MIBK (25.8 kg) and ion-exchanged water (7.0 kg) were charged (added), and the precipitated crystals were filtered and rinsed with ion-exchanged water. Next, a series of operations, that is, the crystals were dispersed in 1N hydrochloric acid (4.9 kg) and ion-exchanged water (4.9 kg) at 50°C, washed, filtered, and rinsed with ion-exchanged water at 50°C, were carried out twice. Furthermore, the crystals were dispersed in ion-exchanged water (10.0 kg) at 50°C, washed, filtered, rinsed several times with a mixture of ion-exchanged water/methanol (volume ratio 50/50), and further rinsed several times with methanol. The obtained crystals were dried under reduced pressure at 60°C to obtain 1.44 kg (yield 96%, HPLC purity 99.0 area%) of 6,6'-bis(methoxycarbonyl)-2,2'-dimethoxy-1,1'-binaphthyl (crude 2,6-BMN-m) as a crude product.

Then, the obtained crude 2,6-BMN-m (700 g) was dissolved in tetrahydrofuran (THF, 8.9 kg) by heating at about 65°C, concentrated and adsorbed on silica gel (2.1 kg), and purified by column development using a solvent in which solvent A and solvent B were mixed in the solvent ratio (volume ratio) shown in Table 2, in accordance with the addition order, amount, and number of times shown in Table 2 below.

The resulting solution was then concentrated, dispersed in methanol (2.1 kg) at room temperature and washed, and then dried under reduced pressure at 60° C. to obtain 650 g (yield 93%, HPLC purity 99.8% by area) of crystals of 2,6-BMN-m represented by the following formula. The results of ¹ H-NMR are shown below.

¹ H-NMR (CDCl ₃ , 300 MHz): δ (ppm) 3.8 (s, 6H), 3.9 (s, 6H), 7.1 (d, 2H), 7.5 (d, 2H), 7.8 (dd, 2H), 8.1 (d, 2H), 8.6 (s, 2H).

<Preparation of Thermoplastic Resin>
[Comparative Example 1]
A polyester resin was prepared according to Example 5 described in JP 2017-171885 A (Patent Document 2).

[Reference Example 1]
In the reactor, 2,3-BMN-m (10.76 g (25 mmol)) as a dicarboxylic acid component, FDP-m (8.46 g (25 mmol)), BNEF (24.24 g (45 mmol)) as a diol component, EG (6.51 g (105 mmol)), titanium (IV) tetrabutoxide (5.1 mg (15 μmol)), calcium acetate monohydrate (4.4 mg (25 μmol)) as a catalyst for transesterification and polycondensation reaction were charged, and the mixture was gradually heated to 250 ° C. under a nitrogen atmosphere, stirred, and transesterification reaction was carried out. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (15.8 mg (75 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 285 ° C. and 150 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 2]
In the reactor, 2,6-BMN-m (8.61 g (20 mmol)) and FDP-m (6.77 g (20 mmol)) were charged as dicarboxylic acid components, BNEF (19.38 g (36 mmol)) as diol components, EG (5.22 g (84 mmol)), and titanium (IV) tetrabutoxide (2.7 mg (8 μmol)) as a catalyst for transesterification and polycondensation reactions were charged, and the mixture was gradually heated to 250 ° C. under a nitrogen atmosphere, stirred, and transesterification was performed. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (12.6 mg (60 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 285 ° C. and 120 Pa, the pressure was reduced, and the polycondensation reaction was performed until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 3]
Into a reactor, 2,6-BMN-m (46.49 g (108 mmol)) as a dicarboxylic acid component, FDP-m (4.07 g (12 mmol)), EG (22.36 g (360 mmol)) as a diol component, and titanium (IV) tetrabutoxide (10.2 mg (30 μmol)) as a catalyst for transesterification and polycondensation reaction were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually raised to 295 ° C. and 170 Pa, the pressure was reduced, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 4]
Into the reactor, 2,6-BMN-m (36.16 g (84 mmol)) as a dicarboxylic acid component, FDP-m (12.18 g (36 mmol)), EG (22.36 g (360 mmol)) as a diol component, and titanium (IV) tetrabutoxide (6.8 mg (20 μmol)) as a catalyst for transesterification and polycondensation reaction were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (4.2 mg (20 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 290 ° C. and 170 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 5]
Into the reactor, 2,6-BMN-m (25.83 g (60 mmol)) as a dicarboxylic acid component, FDP-m (20.29 g (60 mmol)), EG (22.36 g (360 mmol)) as a diol component, and titanium (IV) tetrabutoxide (4.1 mg (12 μmol)) as a catalyst for transesterification and polycondensation reaction were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (4.2 mg (20 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 284 ° C. and 140 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 6]
Into the reactor, 2,6-BMN-m (24.11 g (56 mmol)) as a dicarboxylic acid component, FDP-m (8.13 g (24 mmol)), BINOL-2EO (20.97 g (56 mmol)) as a diol component, EG (16.41 g (264 mmol)), titanium (IV) tetrabutoxide (6.8 mg (20 μmol)) as a catalyst for transesterification and polycondensation reaction were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere, stirred, and transesterification reaction was carried out. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (4.2 mg (20 μmol)) was added as a heat stabilizer, and 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 while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 7]
In the reactor, 2,6-BMN-m (24.11 g (56 mmol)) and FDP-m (8.13 g (24 mmol)) were charged as dicarboxylic acid components, BPEF (24.56 g (56 mmol)) as diol components, EG (16.40 g (264 mmol)), and titanium (IV) tetrabutoxide (3.4 mg (10 μmol)) as a catalyst for transesterification and polycondensation reactions were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (6.7 mg (32 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 286 ° C. and 170 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 8]
Into the reactor, 2,6-BMN-m (21.52 g (50 mmol)) and 2-DNFDP-m (29.54 g (50 mmol)) were charged as dicarboxylic acid components, EG (18.62 g (300 mmol)) as a diol component, and titanium (IV) tetrabutoxide (6.8 mg (20 μmol)) was charged as a catalyst for transesterification and polycondensation reactions, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (5.3 mg (25 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 279 ° C. and 130 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 9]
Into the reactor, 2,6-BMN-m (12.91 g (30 mmol)) and 2-DNFDP-m (41.35 g (70 mmol)) were charged as dicarboxylic acid components, EG (18.62 g (300 mmol)) as a diol component, and titanium (IV) tetrabutoxide (6.8 mg (20 μmol)) was charged as a catalyst for transesterification and polycondensation reactions, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (5.3 mg (25 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 279 ° C. and 130 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 10]
In the reactor, 2,6-BMN-m (21.52 g (50 mmol)) as dicarboxylic acid components, FDP-m (10.15 g (30 mmol)), DDA-m (5.17 g (20 mmol)), BPEF (30.7 g (70 mmol)) as diol components, EG (14.28 g (230 mmol)), titanium (IV) tetrabutoxide (4.3 mg (12.5 μmol)) as a catalyst for transesterification and polycondensation reaction were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere, stirred, and transesterification reaction was carried out. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (12.6 mg (60 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 278 ° C. and 220 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 11]
Into the reactor, 2,6-BMN-m (24.11 g (56 mmol)) and FDP-m (8.12 g (24 mmol)) were charged as dicarboxylic acid components, BPEF (10.52 g (24 mmol)) and 1,5-PDO (2.50 g (24 mmol)) as diol components, EG (11.92 g (192 mmol)), and titanium (IV) tetrabutoxide (2.7 mg (8 μmol)) as a catalyst for transesterification and polycondensation reaction were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere and stirred to carry out transesterification. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (8.4 mg (40 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 282 ° C. and 150 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 12]
In the reactor, 2,6-BMN-m (25.83 g (60 mmol)) and FDP-m (13.54 g (40 mmol)) were charged as dicarboxylic acid components, BPEF (17.54 g (40 mmol)) as diol components, EG (16.14 g (260 mmol)), and titanium (IV) tetrabutoxide (3.4 mg (10 μmol)) as a catalyst for transesterification and polycondensation reactions were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (10.5 mg (50 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 282 ° C. and 170 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 13]
In the reactor, 2,6-BMN-m (19.37 g (45 mmol)) and FDP-m (18.61 g (55 mmol)) were charged as dicarboxylic acid components, BPEF (36.40 g (83 mmol)) as diol components, EG (13.47 g (217 mmol)), and titanium (IV) tetrabutoxide (3.4 mg (10 μmol)) as a catalyst for transesterification and polycondensation reactions were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (10.5 mg (50 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 278 ° C. and 140 Pa, the pressure was reduced, and the polycondensation reaction was carried out until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 14]
In the reactor, 2,6-BMN-m (10.76 g (25 mmol)) and FDP-m (25.38 g (75 mmol)) were charged as dicarboxylic acid components, BPEF (6.58 g (15 mmol)), BNEF (37.70 g (70 mmol)), and EG (13.35 g (215 mmol)) were charged as diol components, and titanium (IV) tetrabutoxide (3.4 mg (10 μmol)) was charged as a catalyst for transesterification and polycondensation reactions, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere and stirred to perform a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, dibutyl phosphate (8.4 mg (40 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 276 ° C. and 120 Pa, the pressure was reduced, and the polycondensation reaction was performed until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 15]
In the reactor, 2,6-BMN-m (8.61 g (20 mmol)), FDP-m (3.38 g (10 mmol)), DMT (13.59 g (70 mmol)) as dicarboxylic acid components, BPEF (39.47 g (90 mmol)) as diol components, EG (13.03 g (210 mmol)), calcium acetate dihydrate (14.1 mg (80 μmol)) titanium (IV) tetrabutoxide (5.1 mg (15 μmol)) as catalysts for transesterification and polycondensation reactions were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere, stirred, and transesterification was performed. After removing the alcohol component generated by the transesterification reaction, dibutyl phosphate (9.5 mg (45 μmol)) was added as a heat stabilizer, and the temperature was gradually raised to 269 ° C. and 130 Pa, the pressure was reduced, and the polycondensation reaction was performed until a predetermined stirring torque was reached while removing EG. After the reaction was completed, the contents were removed from the reactor to obtain a polyester resin.

[Example 16] Polyester carbonate In a reactor, 2,6-BMN-m (15.5 g (36 mmol)) as a dicarboxylic acid component, DPC (18.77 g (87.6 mmol)) as a carbonate bond forming component, BPEF (31.57 g (72 mmol)), BINOL-2EO (13.48 g (36 mmol)), 1,5-PDO (1.25 g (12 mmol)) as a diol component, titanium (IV) tetrabutoxide (6.1 mg (18 μmol)) as a catalyst for transesterification and polycondensation reaction were charged, and the mixture was gradually heated to 240 ° C. under a nitrogen atmosphere, stirred, and transesterification reaction was carried out. After removing the alcohol component and phenol component generated by the transesterification reaction, the temperature was gradually raised to 269 ° 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.

The charge ratios for the Comparative Examples, Reference Examples, and Examples are shown in Table 3, and the evaluation results for each of the obtained polyester resins, i.e., the polymer composition ratio (the ratio of constituent units derived from each polymerization component used in the preparation) and each physical property value, are shown in Tables 4 and 5.

As is clear from Tables 3 to 5, compared to the comparative examples, the polyester resins obtained in the examples exhibited high refractive indexes and low Abbe numbers without excessively increasing birefringence, and also exhibited relatively high Tg.

Comparative Example 1, Reference Example 1, and Example 2 are examples prepared by varying the type of dicarboxylic acid component having a binaphthyl skeleton. Compared with Comparative Example 1 (BNAC-E) and Reference Example 1 (2,3-BMN-m), which form the main chain at the 2,2' or 3,3' positions of the binaphthyl skeleton, Example 2 (2,6-BMN-m), which forms the main chain at the 6,6' positions, is able to achieve a high refractive index, low Abbe number, and high Tg while maintaining low birefringence, and it was found that 2,6-BMN-m is a particularly effective dicarboxylic acid component for achieving a good balance between these four properties. It was an unexpected result that each property could be significantly improved by changing the substitution position on the binaphthyl skeleton.

The polyester resin of the embodiment satisfies the four characteristics (high refractive index, low Abbe number, low birefringence, and high Tg) in a relatively balanced manner, and since it is possible to prepare a resin with a low Abbe number in particular, it can be effectively used as an optical lens. In other words, it is possible to expand the options for optical lens materials with a low Abbe number, and to improve the design freedom of lens units formed from multiple lenses.

Of these examples, Examples 2, 3, and 7 have particularly high Tg and are preferred for use as highly heat-resistant lenses for vehicles, with Example 2 being particularly preferred in terms of high refractive index and low birefringence, and Example 7 being even more preferred in terms of extremely low birefringence. Furthermore, Example 6 is even more preferred in terms of a particularly excellent balance of the four properties and excellent moldability (or productivity). Furthermore, Examples 12 to 14 are preferred in terms of a particularly excellent balance of the four properties and low birefringence, with Example 13 being particularly preferred.

[Reference Example 2]
The physical properties and optical properties of ARTON F4520 (manufactured by JSR Corporation) as a cyclic olefin resin were measured.

[Reference Example 3]
The procedure was carried out in accordance with Example 13 described in WO2016-147847. That is, 450 g of ARTON F4520 pellets and 50 g of BNEF as a fluorene compound were kneaded using a twin-screw extruder to obtain a resin composition.

[Example 17]
90 g of ARTON F4520 pellets and 10 g of 2,6-BMN-m were kneaded using a twin-screw extruder to obtain a resin composition.

As is clear from the results in Table 6, the resin composition of Example 17 had higher fluidity and a reduced Abbe number compared to the reference example.

The thermoplastic resin and resin composition of the present invention exhibit high heat resistance, and therefore can be suitably used not only as heat-resistant members, but also in various applications requiring heat resistance. For example, they may be used in coating agents or coating films, specifically, paints, inks, protective films for electronic devices and liquid crystal members, 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, heat sensitive 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, and the like; mechanical materials or mechanical parts (equipment), specifically, automotive materials or parts, aerospace-related materials or parts, sliding members, and the like.

In addition to high heat resistance, thermoplastic resins and resin compositions also have a good balance of optical properties, such as a high refractive index, low Abbe number, and low birefringence, making them effective for use as optical components.

Typical optical components include optical films (optical sheets) such as films for liquid crystal displays and films for organic electroluminescence displays; optical lenses such as lenses for glasses and cameras; prisms, holograms, optical fibers, etc.

Examples of optical films include polarizing films, polarizing elements and polarizing plate protective films that constitute polarizing films, phase difference films, alignment films, viewing angle expansion (compensation) films, diffusion plates (films), prism sheets, light guide plates, brightness enhancement films, near-infrared absorbing films, reflective films, anti-reflection (AR) films, reflection reduction (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, and adhesive or release layers between optical films. 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. 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. Thermoplastic resins can effectively reduce the Abbe number, and are therefore suitable for use in lenses that require a low Abbe number, such as camera lenses. Typical devices or equipment in which such optical lenses are mounted 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). Thermoplastic resins in particular have high heat resistance, and are therefore suitable for use in applications where use in high-temperature environments, such as in-vehicle optical lenses, is anticipated.

Claims (16)

A thermoplastic resin containing a dicarboxylic acid unit (A), wherein the dicarboxylic acid unit (A) is at least one selected from the group consisting of a carboxylic acid unit represented by the following formula (1):

(In the formula, R ^1a and R ^1b each independently represent a hydrogen atom or a substituent,
R ^2a and R ^2b each independently represent a substituent, and k1 and k2 each independently represent an integer of 0 to 5.
The first dicarboxylic acid unit (A1) is represented by the following formula (1a):

(In the formula, R ^1a and R ^1b , R ^2a and R ^2b , k1 and k2 are the same as in formula (1).)
A thermoplastic resin containing a dicarboxylic acid unit represented by the formula : The thermoplastic resin according to claim 1, wherein in formula (1), R ^1a and R ^1b are alkoxy groups. The dicarboxylic acid unit (A) is represented by the following formula (2a) or (2b):

(In the formula, R ^4a represents a substituent, m1 represents an integer of 0 to 8,
A ^1a and A ^1b each independently represent a divalent hydrocarbon group which may have a substituent;
R ^4b represents a substituent; m2 represents an integer of 0 to 8;
A ^1c represents a divalent hydrocarbon group which may have a substituent;
m3 represents an integer of 0 to 4.
The thermoplastic resin according to claim 1 or 2 , which contains a second dicarboxylic acid unit (A2) represented by the following formula: 4. The thermoplastic resin according to claim 3 , wherein the ratio of the first dicarboxylic acid unit (A1) to the second dicarboxylic acid unit (A2) is the former/the latter (molar ratio)=30/70 to 95/5. the thermoplastic resin is a polyester resin further containing a diol unit (B);
The diol unit (B) is represented by the following formula (3):

(wherein ^A2 represents a linear or branched alkylene group, and n represents an integer of 1 or more), a first diol unit (B1) represented by the following formula (4):

(In the formula, ^Z1 and ^Z2 each independently represent an aromatic hydrocarbon ring;
^R5 represents a substituent; p represents an integer of 0 to 8;
R ^6a and R ^6b each independently represent a substituent; q1 and q2 each independently represent 0 or an integer of 1 or more;
^A3a and ^A3b each independently represent a linear or branched alkylene group, and r1 and r2 each independently represent an integer of 0 or 1 or more.
and a second diol unit (B2) represented by the following formula (5):

(In the formula, ^A4 represents a direct bond or an alkylene group,
^A5a and ^A5b each represent a linear or branched alkylene group; s1 and s2 each independently represent 0 or an integer of 1 or more;
R ^7a and R ^7b each independently represent a substituent, and t1 and t2 each independently represent an integer of 0 to 6.
The thermoplastic resin according to any one of claims 1 to 4 , further comprising at least one diol unit selected from the third diol units (B3) represented by: In formula (3), ^A2 is a linear or branched _C2-6 alkylene group, n is an integer of 1 to 5,
In formula (4), Z ¹ and Z ² are monocyclic aromatic hydrocarbon rings or condensed polycyclic aromatic hydrocarbon rings, A ^3a and A ^3b are linear or branched C _2-6 alkylene groups, and r1 and r2 are integers of 0 to 10;
The thermoplastic resin according to claim 5, wherein, in formula (5), A ⁴ is a direct bond or a C _1-2 alkylene group, A ^5a and A ^5b are linear or branched C _2-6 alkylene groups, and s1 and s2 are integers of 0 to 10 . 7. The thermoplastic resin according to claim 5 , wherein the proportion of the first diol units (B1) is 1 mol % or more based on the total diol units (B). The thermoplastic resin according to any one of claims 5 to 7 , wherein a ratio of the first diol unit (B1) to the second diol unit (B2) (molar ratio) is from 1/99 to 50/50. The thermoplastic resin according to any one of claims 5 to 8 , wherein a ratio of the first diol unit (B1) to the third diol unit (B3) is the former/the latter (molar ratio) = 5/95 to 50/50. A method for producing the thermoplastic resin according to any one of claims 1 to 9 , comprising polymerizing a polymerization component containing at least a first dicarboxylic acid component corresponding to the first dicarboxylic acid unit (A1). The following formula (1A)

(In the formula, R ^1a and R ^1b each independently represent a C _1-5 alkoxy group,
R ^2a and R ^2b each independently represent a substituent; k1 and k2 each independently represent an integer of 0 to 5;
R ^3a and R ^3b each independently represent a C _1-5 alkoxy group.
A compound represented by the formula: The following formula (1B)

(In the formula, R ^1a and R ^1b each independently represent a hydrogen atom or a substituent,
R ^2a and R ^2b each independently represent a substituent; k1 and k2 each independently represent an integer of 0 to 5;
^R3a and ^R3b each independently represent a hydroxyl group, an alkoxy group, or a halogen atom.
An Abbe number reducer represented by the formula: A resin composition comprising a thermoplastic resin and the Abbe number reducing agent according to claim 12 . A molded article comprising the thermoplastic resin according to any one of claims 1 to 9 or the resin composition according to claim 13 . The molded article according to claim 14 , which is an optical member. The molded article according to claim 14 or 15 , which is an optical film or an optical lens.