JP7577962B2 - Aromatic Polycarbonate Resin - Google Patents

Description

The present invention relates to an aromatic polycarbonate resin that contains specific carbonate structural units and thus has high heat resistance capable of withstanding production and use in high-temperature environments, high thermal stability enabling injection molding over a wide temperature range, and a high refractive index, low birefringence, and excellent moldability useful as an optical molding material, as well as an aromatic polycarbonate resin composition containing this aromatic polycarbonate resin, a molded article thereof, and a method for producing the molded article.

Polycarbonate resins are used as optical molding materials because of their excellent transparency, dimensional stability, and mechanical properties. Patent Document 1 discloses a polycarbonate resin that mainly contains repeating units having a 9,9-bisphenylfluorene skeleton as a polycarbonate resin with excellent optical properties. In the examples of Patent Document 1, a polycarbonate resin is prepared using 2,2'-[9H-fluoren-9-ylidenebis(4,1-phenyleneoxy)]-bisethanol [9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (abbreviation: BPEF)] as a polymerization component.
The glass transition temperature of the polycarbonate resin described in Patent Document 1 is relatively high, at about 145° C. However, it may not be applicable to applications (such as vehicle-mounted lenses) that are expected to be manufactured or used in a high-temperature environment.

Patent Document 2 describes, as high refractive optical polycarbonate resins, copolymer polycarbonate resins of 1,1'-bis(4-hydroxyphenyl)-1-phenyl-ethane (bisphenol AP) and 2,2'-bis(4-hydroxyphenyl)-propane (bisphenol A), and copolymer polycarbonate resins of bis(4-hydroxyphenyl)diphenylmethane (bisphenol BP) and bisphenol A. However, although Patent Document 2 describes the refractive index and molding fluidity, it does not describe heat resistance and birefringence, and may not be applicable to applications requiring high heat resistance or low birefringence.

Patent Document 3 discloses a polycarbonate copolymer in which 50 to 95 mol % of the total aromatic dihydroxy component is 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (BCF) and 50 to 5 mol % is a general bisphenol, as a polycarbonate resin with good heat resistance and thermal stability, low birefringence, and excellent transparency. However, Patent Document 3 only describes improvements in heat resistance and thermal stability, and birefringence, and makes no mention of the refractive index, which is important for optical molding materials.

Patent Document 4 discloses a polycarbonate resin that uses 9,9-bis(6-hydroxy-2-naphthyl)fluorene as a diol, as a polycarbonate resin with high heat resistance, high refractive index, and low birefringence. However, Patent Document 4 only describes the heat resistance, refractive index, and birefringence of the stretched film, and does not mention the thermal stability and moldability that are important for optical molding materials.

Patent Document 5 describes an optical member made of a polycarbonate resin containing a structural unit (A) derived from 4,4'-dihydroxytetraphenylmethane and a structural unit (B) derived from 1,1-bis(4-hydroxyphenyl)decane or 4,4'-(m-phenylenediisopropylidene)diphenol in a specified ratio, but does not suggest the effect of introducing the carbonate structural unit (B) of the aromatic polycarbonate resin of the present invention.

Patent Document 6 describes a lens made of a polycarbonate copolymer (I) containing a specified ratio of units (A) derived from 9,9-bis(4-hydroxy-3-methylphenyl)fluorene and units (B) derived from 1,1-bis(4-hydroxyphenyl)decane, but does not include any description suggesting the effect of combining the carbonate structural units (A) and carbonate structural units (B) of the aromatic polycarbonate resin of the present invention.

Patent Document 7 describes an aromatic polycarbonate resin that contains the carbonate structural unit (B) of the aromatic polycarbonate resin of the present invention and has high fluidity, thin-wall moldability, and excellent transparency, impact strength, and bending resistance. However, there is no description of an aromatic polycarbonate resin that contains the carbonate structural unit (A) and carbonate structural unit (B) of the aromatic polycarbonate resin of the present invention, nor any suggestion of the resulting effects on the refractive index and birefringence.

Patent Document 8 describes a flow modifier for thermoplastic resins that contains an aromatic polycarbonate copolymer that contains carbonate structural units (A) and carbonate structural units (B) in a specified ratio, but this aromatic polycarbonate copolymer is a flow modifier for thermoplastic resins, and there is no mention of the aromatic polycarbonate resin of the present invention. Furthermore, Patent Document 8 does not consider the refractive index or birefringence of the resin as an optical molding material.

Japanese Patent Application Publication No. 10-101787 JP 2017-210569 A JP 2004-331688 A JP 2018-104691 A JP 2009-080425 A International Publication No. 2009/028699 International Publication No. 2017/099227 International Publication No. 2017/099233

The object of the present invention is to provide an aromatic polycarbonate resin that has high heat resistance capable of withstanding production and use in high-temperature environments, high thermal stability enabling injection molding over a wide temperature range, and a high refractive index, low birefringence, and excellent moldability that are useful as an optical molding material, as well as an aromatic polycarbonate resin composition and molded article that contain the resin.

Means for Solving the Problems The present inventors have conducted intensive research to solve the above problems and have discovered that an aromatic polycarbonate resin having a specific combination of carbonate structural units has excellent heat resistance, thermal stability, strength, and moldability, as well as a high refractive index and low birefringence, thereby completing the present invention.
That is, the gist of the present invention lies in the following [1] to [17].

[1] An aromatic polycarbonate resin containing a carbonate structural unit (A) represented by the following formula (1) and a carbonate structural unit (B) represented by the following formula (5).

(In formula (1), rings Z ¹ and Z ² each independently represent an aromatic hydrocarbon ring. R ¹ and R ² each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom. a and b each independently represent an integer of 0 or more. When a and b are 2 or more and there are multiple R ^1s and multiple R ^2s , the multiple R ^1s and R ^2s may be the same as or different from each other. At least two groups among the multiple R ^1s and/or R ^2s may be bonded to each other to form a ring. X is a group selected from the group consisting of divalent groups represented by the following formulas (2) to (4). The * marks in formulas (2) to (4) indicate the bonding sites with rings Z ¹ and Z ² in formula (1).)

(In formula (2), R ³ is a hydrogen atom or an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms. R ⁴ is an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, or a halogen atom. c represents an integer of 0 to 5. When c is 2 or more and there are multiple R ^4s , the multiple R ^4s may be the same or different from each other. In addition, at least two groups among the multiple R ^4s may be bonded to each other to form a ring.)

(In formula (3), R ⁵ and R ⁶ each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, or a halogen atom. d and e each independently represent an integer of 0 to 5. When d and e are 2 or more and there are a plurality of R ^5s and R ^6s , the plurality of R ^5s and R ^6s may be the same or different. Furthermore, at least two of the plurality of R ^5s and/or R ^6s may be bonded to each other to form a ring.)

(In formula (4), rings Z ³ and Z ⁴ each independently represent an aromatic hydrocarbon ring. R ⁷ and R ⁸ each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom. f and g each independently represent an integer of 0 or greater. At least two of the multiple R ^7s and/or R ^8s may be bonded to each other to form a ring.)

(In formula (5), R ⁹ and R ¹⁰ each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom. h and i each independently represent an integer of 0 to 4. When h and i are 2 or more and there are a plurality of R ^{9 s} and R ^{10 s} , the plurality of R ^{9 s} and R ^{10 s} may be the same as or different from each other. In addition, at least two groups among the plurality of R ^{9 s} and/or R ^{10 s} may be bonded to each other to form a ring. R ¹¹ and R ¹² each independently represent a hydrogen atom or an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms. However, the total number of carbon atoms of R ¹¹ and R ¹² is 11 or more and 40 or less.)

[2] The aromatic polycarbonate resin according to [1], in which the carbonate structural unit (A) is contained in an amount of 40 mol% or more and less than 100 mol%, when the total number of moles of all carbonate structural units constituting the resin is taken as 100 mol%.

[3] An aromatic polycarbonate resin according to [1] or [2], in which the carbonate structural unit (B) is contained in an amount of more than 0 mol% and not more than 60 mol%, when the total number of moles of all carbonate structural units constituting the resin is taken as 100 mol%.

[4] The aromatic polycarbonate resin according to any one of [1] to [3], wherein in the formula (5), at least one of R ¹¹ and R ¹² has 11 or more carbon atoms.

[5] The aromatic polycarbonate resin according to any one of [1] to [4], wherein in the formula (5), R ¹¹ or R ¹² is a hydrogen atom.

[6] The aromatic polycarbonate resin according to [5], wherein the formula (5) is the following formula (6):

[7] The aromatic polycarbonate resin according to any one of [1] to [6], wherein in the formula (1), rings Z ¹ and Z ² are each independently selected from a benzene ring, a naphthalene ring, and an anthracene ring.

[8] The aromatic polycarbonate resin according to any one of [1] to [7], wherein in the formula (4), rings Z ³ and Z ⁴ are each independently selected from a benzene ring, a naphthalene ring, and an anthracene ring.

[9] The aromatic polycarbonate resin according to any one of [1] to [8], wherein in the formula (1), X is any one selected from the group consisting of divalent groups represented by the following formulas (7) to (9) (the * marks in the formulas (7) to (9) represent bonding sites with the ^rings Z 1 and Z ² in the formula (1). In addition, in the formulas (7) to (9), the benzene ring or the fluorene ring may have a substituent).

[10] The aromatic polycarbonate resin according to any one of [1] to [9], wherein the formula (1) is any one selected from the group consisting of the following formulas (10) to (14):

[11] An aromatic polycarbonate resin according to any one of [1] to [10], having a Tg of 150 to 250°C.

[12] An aromatic polycarbonate resin composition comprising the aromatic polycarbonate resin according to any one of [1] to [11] and at least one additive selected from the group consisting of a heat stabilizer, an antioxidant, an ultraviolet absorber, a brightness enhancer, a dye, a pigment, a release agent, a flow modifier, and an impact resistance improver.

[13] An aromatic polycarbonate resin composition comprising the aromatic polycarbonate resin according to any one of [1] to [11] and other resins.

[14] A molded article obtained using the aromatic polycarbonate resin according to any one of [1] to [11], or the aromatic polycarbonate resin composition according to [12] or 13.

[15] The molded article according to [14], wherein the molded article is an optical component.

[16] The molded body according to [15], wherein the optical component is at least one optical lens selected from the group consisting of an in-vehicle lens, a spectacle lens, a pickup lens, a camera lens, a microarray lens, a projector lens, and a Fresnel lens.

[17] A method for producing a molded article using the aromatic polycarbonate resin according to any one of [1] to [11], or the aromatic polycarbonate resin composition according to [12] or [13], characterized in that the maximum temperature during molding is 300°C or higher.

The aromatic polycarbonate resin of the present invention contains the carbonate structural unit (A) represented by the formula (1) and the carbonate structural unit (B) represented by the formula (5). That is, the aromatic polycarbonate resin of the present invention is a copolymer polycarbonate resin containing the carbonate structural unit (A) represented by the formula (1) and the carbonate structural unit (B) represented by the formula (5).
The aromatic polycarbonate resin of the present invention contains the carbonate structural unit (A), which improves heat resistance, refractive index, and birefringence, and contains the carbonate structural unit (B), which improves strength while maintaining high heat resistance and high refractive index, and improves melt fluidity, which improves moldability and reduces birefringence of molded products. Furthermore, the aromatic polycarbonate resin of the present invention has high thermal stability and can be produced or injection molded at high temperatures because its main skeleton is not a carbonate bond derived from an aliphatic hydroxy compound.

The present invention provides an aromatic polycarbonate resin that has excellent heat resistance, thermal stability, and strength, as well as a high refractive index, low birefringence, and excellent moldability. Therefore, the aromatic polycarbonate resin of the present invention and an aromatic polycarbonate resin composition containing the same can be easily processed into optical components such as lenses by injection molding. These optical components have high heat resistance compared to optical components using conventional polycarbonate resins, while also having a high refractive index and low birefringence, and are therefore useful as high-performance optical components.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples, but the present invention should not be construed as being limited to the embodiments and examples shown below.
In this specification, unless otherwise specified, "to" is used to mean that the numerical values before and after it are included as the lower and upper limits. In addition, the "structural unit" refers to a partial structure sandwiched between adjacent linking groups in a polymer, and a partial structure sandwiched between a polymerization reactive group present at the terminal portion of a polymer and a linking group adjacent to the polymerization reactive group. In addition, the linking group refers to a carbonate bond portion (carbonate group) and an ester bond portion (ester group).

In the present invention, the term "polycarbonate resin" refers to a resin in which the structural units constituting the resin contain a portion (carbonate group) linked by a carbonate bond. The aromatic polycarbonate resin of the present invention may contain any portion (ester group) linked by an ester bond, so long as it does not impair the effects of the present invention. In other words, the aromatic polycarbonate resin of the present invention also includes polyester carbonate resins.

[Aromatic polycarbonate resin]
The aromatic polycarbonate resin of the present invention contains a carbonate structural unit (A) represented by the above formula (1) (hereinafter simply referred to as "carbonate structural unit (A)") and a carbonate structural unit (B) represented by the above formula (5) (hereinafter simply referred to as "carbonate structural unit (B)". That is, the aromatic polycarbonate resin of the present invention is a copolymer polycarbonate resin containing the carbonate structural unit (A) and the carbonate structural unit (B).

<Carbonate structural unit (A)>
The carbonate structural unit (A) is a structural unit represented by the following formula (1).

(In formula (1), rings Z ¹ and Z ² each independently represent an aromatic hydrocarbon ring. ^{R 1} and R ² each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom. a and b each independently represent an integer of 0 or more. When a and b are 2 or more and there are a plurality of R ^1s and R ^2s , the plurality of R ^1s and R ^2s may be the same as or different from each other. In addition, at least two groups among the plurality of R ^1s and/or R ^2s may be bonded to each other to form a ring. X is a group selected from the group consisting of divalent groups represented by formulas (2) to (4) shown later.)

In the aromatic polycarbonate resin of the present invention, the content ratio of the carbonate structural unit (A) is not particularly limited, but when the total number of moles of all the carbonate structural units constituting the resin is taken as 100 mol%, the carbonate structural unit (A) is preferably 40 mol% or more and less than 100 mol%, more preferably 60 mol% or more and 99.9 mol% or less, even more preferably 72 mol% or more and 99.5 mol% or less, particularly preferably 81 mol% or more and 99 mol% or less, and most preferably 90 mol% or more and 98 mol% or less.

If the content ratio of carbonate structural unit (A) is above the lower limit, the refractive index of the aromatic polycarbonate resin of the present invention is high, which is advantageous when used as an optical molding material. If the content ratio of carbonate structural unit (A) is above the lower limit, the birefringence of the aromatic polycarbonate resin of the present invention is small, which is advantageous when used as an optical molding material. Furthermore, if the content ratio of carbonate structural unit (A) is above the lower limit, the heat resistance, i.e., Tg (glass transition temperature), of the aromatic polycarbonate resin of the present invention is high, which is advantageous when used as a molding material.
On the other hand, when the carbonate structural unit (A) is less than the above upper limit, the aromatic polycarbonate resin of the present invention has high molding flowability, which is advantageous when used as a molding material.

In the formula (1), rings ^Z1 and ^Z2 each independently represent an aromatic hydrocarbon ring. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring. From the viewpoint of improving the flowability of the aromatic polycarbonate resin, rings ^Z1 and ^Z2 each independently preferably represent a benzene ring or a naphthalene ring, and more preferably represent a benzene ring.

R ¹ and R ² are each independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom, provided that at least two groups of R ¹ and/or R ² may be bonded to each other to form a ring.

In the above, the substituent is not particularly limited as long as it does not interfere with the effects of the present invention, but is preferably selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

The unsubstituted or substituted alkyl group having 1 to 10 carbon atoms for R ¹ and R ² may be linear, branched, or cyclic. Examples of the unsubstituted or substituted alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an n-hexyl group, a cyclohexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, and an n-decyl group.

Examples of the unsubstituted or substituted aryl group having 6 to 10 carbon atoms for R ¹ and R ² include unsubstituted phenyl and naphthyl groups. Examples of substituted aryl groups include methylphenyl (tolyl), ethylphenyl, propylphenyl, butylphenyl, dimethylphenyl, and trimethylphenyl groups. From the viewpoint of the thermal stability and heat resistance of the aromatic polycarbonate resin of the present invention, unsubstituted aryl groups are preferred.

Examples of the unsubstituted or substituted acyl group having 1 to 10 carbon atoms for R ¹ and R ² include a methanoyl group, an ethanoyl group, a propanoyl group, a butanoyl group, a pentanoyl group, a hexanoyl group, a heptanoyl group, an octanoyl group, a nonanoyl group, a decanoyl group, a benzoyl group, an acrylyl group, a chloroethanoyl group, a dichloroethanoyl group, a trichloroethanoyl group, a bromoethanoyl group, and a fluoroethanoyl group.

Examples of the oxygen atom having a substituent of ^R1 or ^R2 include a hydroxy group; an alkoxy group such as a methoxy group, an ethoxy group, a propyloxy group, a hexyloxy group, a cyclohexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, a phenoxy group, or a benzyloxy group; and an oxygen atom forming a bridge structure between rings ^Z1 and ^Z2 described later.

Examples of the sulfur atom having a substituent of R ¹ or R ² include a thiol group; alkylthio groups such as a methylthio group, an ethylthio group, a propylthio group, a hexylthio group, a cyclohexylthio group, a heptylthio group, an octylthio group, a nonylthio group, and a decylthio group; arylthio groups such as a phenylthio group and a benzylthio group; a sulfo group; a sulfur atom bridging the ring Z ¹ and the ring Z ² described later, and a sulfonyl group.

Examples of the silicon atom having a substituent of R ¹ or R ² include a silyl group, a monomethylsilyl group, a dimethylsilyl group, a trimethylsilyl group, a triethylsilyl group, and a silicon atom forming a bridge structure between rings Z ¹ and Z ² described below.

Examples of the halogen atom for R ¹ and R ² include a chlorine atom, a bromine atom, and a fluorine atom.

When at least two groups of ^R1 and/or ^R2 are bonded to each other to form a ring, examples include the following.
(1) Adjacent ^R1 and ^R1 are bonded to each other to form a fused ring fused to ring ^Z1 .
(2) Adjacent ^R2 and ^R2 are bonded to each other to form a fused ring fused to ring ^Z2 .
(3) ^R1 and ^R2 are bonded to form a bridge structure between ring ^Z1 and ring ^Z2 .
Specific examples of the above case (3) include a bridged structure linking a carbon atom on ring ^Z1 with a carbon atom on ring ^Z2 via -O-, -S-, _-SO2- , -Si-, _-SiH2- , _-SiMe2- , or _-SiEt2- (Me represents a methyl group, and Et represents an ethyl group).

Of these, R ¹ and R ² are preferably a methyl group, a cyclohexyl group, a phenyl group, or a naphthyl group, more preferably a methyl group, a cyclohexyl group, or a phenyl group, still more preferably a methyl group or a phenyl group, and particularly preferably a methyl group.

Each of a and b independently represents an integer of 0 or more. Of these, each of a and b independently represents an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0.

In the formula (1) representing the carbonate structural unit (A), X is a group selected from the group consisting of divalent groups represented by the following formulas (2) to (4). The marks * in the formulas (2) to (4) indicate the bonding sites with the rings Z ¹ and Z ² in the formula (1).

(In formula (2), R ³ is a hydrogen atom or an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms. R ⁴ is an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, or a halogen atom. c represents an integer of 0 to 5. When c is 2 or more and there are multiple R ^4s , the multiple R ^4s may be the same or different from each other. In addition, at least two groups among the multiple R ^4s may be bonded to each other to form a ring.)

In the above formula (2), R ³ is a hydrogen atom or an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms. The unsubstituted or substituted alkyl group having 1 to 10 carbon atoms may be linear, branched, or cyclic. Examples of the unsubstituted or substituted alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an n-hexyl group, a cyclohexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, and an n-decyl group.

Of these, ^R3 is preferably a hydrogen atom, a methyl group, an ethyl group, or a cyclohexyl group, more preferably a hydrogen atom, a methyl group, or an ethyl group, still more preferably a hydrogen atom or a methyl group, and particularly preferably a methyl group.

^R4 is an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom, provided that at least two groups among ^R4 may be bonded to each other to form a ring.

In the above, the substituent is not particularly limited as long as it does not interfere with the effects of the present invention, but is preferably selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

The unsubstituted or substituted alkyl group having 1 to 10 carbon atoms for ^R4 may be linear, branched, or cyclic. Examples of the unsubstituted or substituted alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an n-hexyl group, a cyclohexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, and an n-decyl group.

Examples of the unsubstituted or substituted aryl group having 6 to 10 carbon atoms for ^R4 include unsubstituted phenyl and naphthyl groups. Examples of substituted aryl groups include methylphenyl (tolyl), ethylphenyl, propylphenyl, butylphenyl, dimethylphenyl, and trimethylphenyl groups. From the viewpoint of the thermal stability and heat resistance of the aromatic polycarbonate resin of the present invention, unsubstituted aryl groups are preferred.

Examples of the unsubstituted or substituted acyl group having 1 to 10 carbon atoms for ^R4 include a methanoyl group, an ethanoyl group, a propanoyl group, a butanoyl group, a pentanoyl group, a hexanoyl group, a heptanoyl group, an octanoyl group, a nonanoyl group, a decanoyl group, a benzoyl group, an acrylyl group, a chloroethanoyl group, a dichloroethanoyl group, a trichloroethanoyl group, a bromoethanoyl group, and a fluoroethanoyl group.

Examples of the oxygen atom having a substituent for ^R4 include a hydroxy group; and an alkoxy group such as a methoxy group, an ethoxy group, a propyloxy group, a hexyloxy group, a cyclohexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, a phenoxy group, or a benzyloxy group.

Examples of the sulfur atom having a substituent for ^R4 include a thiol group; alkylthio groups such as a methylthio group, an ethylthio group, a propylthio group, a hexylthio group, a cyclohexylthio group, a heptylthio group, an octylthio group, a nonylthio group, and a decylthio group; arylthio groups such as a phenylthio group and a benzylthio group; and a sulfo group.

Examples of the silicon atom having a substituent for ^R4 include a silyl group, a monomethylsilyl group, a dimethylsilyl group, a trimethylsilyl group, and a triethylsilyl group.

Examples of the halogen atom for ^R4 include a chlorine atom, a bromine atom, and a fluorine atom.

When at least two groups among R ⁴ are bonded to each other to form a ring, for example, adjacent R ⁴ and R ⁴ are bonded to each other to form a fused ring fused to a benzene ring.

Of these, ^R4 is preferably a methyl group, a cyclohexyl group, a phenyl group, or a naphthyl group, more preferably a methyl group, a cyclohexyl group, or a phenyl group, still more preferably a methyl group or a phenyl group, and particularly preferably a methyl group.

c represents an integer of up to 5. Of these, c is preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0.

(In formula (3), R ⁵ and R ⁶ each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, or a halogen atom. d and e each independently represent an integer of 0 to 5. When d and e are 2 or more and there are a plurality of R ^5s and R ^6s , the plurality of R ^5s and R ^6s may be the same or different. Furthermore, at least two of the plurality of R ^5s and/or R ^6s may be bonded to each other to form a ring.)

In the above formula (3), R ⁵ and R ⁶ are each independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom, provided that at least two groups of R ⁵ and/or R ⁶ may be bonded to each other to form a ring.

In the above, the substituent is not particularly limited as long as it does not interfere with the effects of the present invention, but is preferably selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

The unsubstituted or substituted alkyl group having 1 to 10 carbon atoms for R ⁵ and R ⁶ may be linear, branched or cyclic. Examples of the unsubstituted or substituted alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an n-hexyl group, a cyclohexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group and an n-decyl group.

Examples of the unsubstituted or substituted aryl group having 6 to 10 carbon atoms for R ⁵ and R ⁶ include unsubstituted phenyl and naphthyl groups. Examples of substituted aryl groups include methylphenyl (tolyl), ethylphenyl, propylphenyl, butylphenyl, dimethylphenyl, and trimethylphenyl groups. From the viewpoint of the thermal stability and heat resistance of the aromatic polycarbonate resin of the present invention, unsubstituted aryl groups are preferred.

Examples of the unsubstituted or substituted acyl group having 1 to 10 carbon atoms for ^R5 and ^R6 include a methanoyl group, an ethanoyl group, a propanoyl group, a butanoyl group, a pentanoyl group, a hexanoyl group, a heptanoyl group, an octanoyl group, a nonanoyl group, a decanoyl group, a benzoyl group, an acrylyl group, a chloroethanoyl group, a dichloroethanoyl group, a trichloroethanoyl group, a bromoethanoyl group, and a fluoroethanoyl group.

Examples of the oxygen atom having a substituent of ^R5 or ^R6 include a hydroxy group; an alkoxy group such as a methoxy group, an ethoxy group, a propyloxy group, a hexyloxy group, a cyclohexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, a phenoxy group, or a benzyloxy group; and an oxygen atom forming a bridge structure connecting two benzene rings in the formula (3) described later.

Examples of the sulfur atom having a substituent of ^R5 or ^R6 include a thiol group; alkylthio groups such as a methylthio group, an ethylthio group, a propylthio group, a hexylthio group, a cyclohexylthio group, a heptylthio group, an octylthio group, a nonylthio group, and a decylthio group; arylthio groups such as a phenylthio group and a benzylthio group; a sulfo group; and a sulfur atom forming a crosslinking structure connecting two benzene rings in the formula (3) described later, and a sulfonyl group.

Examples of the silicon atom having a substituent of ^R5 or ^R6 include a silyl group, a monomethylsilyl group, a dimethylsilyl group, a trimethylsilyl group, a triethylsilyl group; and a silicon atom forming a cross-linked structure connecting two benzene rings in the formula (3) described later.

Examples of the halogen atom for R ⁵ and R ⁶ include a chlorine atom, a bromine atom, and a fluorine atom.

When at least two groups of ^R5 and/or ^R6 are bonded to each other to form a ring, examples include the following.
(1) Adjacent ^R5 and ^R5 are bonded to each other to form a fused ring fused to a benzene ring.
(2) Adjacent ^R6 and ^R6 are bonded to each other to form a fused ring fused to a benzene ring.
(3) ^R5 and ^R6 combine to form a bridge structure connecting the two benzene rings in formula (3).
Specific examples of the above case (3) include crosslinked structures linking carbon atoms on two benzene rings together, such as -O-, -S-, -SO ₂ -, -Si-, -SiH ₂ -, -SiMe ₂ -, or -SiEt ₂ -.

Of these, R ⁵ and R ⁶ are preferably a methyl group, a cyclohexyl group, a phenyl group, or a naphthyl group, more preferably a methyl group, a cyclohexyl group, or a phenyl group, further preferably a methyl group or a phenyl group, and particularly preferably a methyl group.

d and e each independently represent an integer from 0 to 5. Of these, d and e each independently preferably represent an integer from 0 to 2, more preferably 0 or 1, and even more preferably 0.

(In formula (4), rings Z ³ and Z ⁴ each independently represent an aromatic hydrocarbon ring. R ⁷ and R ⁸ each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom. f and g each independently represent an integer of 0 or greater. At least two of the multiple R ^7s and/or R ^8s may be bonded to each other to form a ring.)

In the above formula (4), rings ^Z3 and ^Z4 each independently represent an aromatic hydrocarbon ring. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring. From the viewpoint of improving the flowability of the aromatic polycarbonate resin, rings ^Z3 and ^Z4 each independently preferably represent a benzene ring or a naphthalene ring, and more preferably represent a benzene ring.

R ⁷ and R ⁸ are each independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom, provided that at least two groups of R ⁷ and/or R ⁸ may be bonded to each other to form a ring.

In the above, the substituent is not particularly limited as long as it does not interfere with the effects of the present invention, but is preferably selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

The unsubstituted or substituted alkyl group having 1 to 10 carbon atoms for R ⁷ and R ⁸ may be linear, branched or cyclic. Examples of the unsubstituted or substituted alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an n-hexyl group, a cyclohexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group and an n-decyl group.

Examples of the unsubstituted or substituted aryl group having 6 to 10 carbon atoms for R ⁷ and R ⁸ include unsubstituted phenyl and naphthyl groups. Examples of substituted aryl groups include methylphenyl (tolyl), ethylphenyl, propylphenyl, butylphenyl, dimethylphenyl, and trimethylphenyl groups. From the viewpoint of the thermal stability and heat resistance of the aromatic polycarbonate resin of the present invention, unsubstituted aryl groups are preferred.

Examples of the unsubstituted or substituted acyl group having 1 to 10 carbon atoms for R ⁷ and R ⁸ include a methanoyl group, an ethanoyl group, a propanoyl group, a butanoyl group, a pentanoyl group, a hexanoyl group, a heptanoyl group, an octanoyl group, a nonanoyl group, a decanoyl group, a benzoyl group, an acrylyl group, a chloroethanoyl group, a dichloroethanoyl group, a trichloroethanoyl group, a bromoethanoyl group, and a fluoroethanoyl group.

Examples of the oxygen atom having a substituent of ^R7 or ^R8 include a hydroxy group; an alkoxy group such as a methoxy group, an ethoxy group, a propyloxy group, a hexyloxy group, a cyclohexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, a phenoxy group, or a benzyloxy group; and an oxygen atom forming a bridge structure between the ring ^Z3 and the ring ^R4 described later.

Examples of the sulfur atom having a substituent of ^R7 or ^R8 include a thiol group; alkylthio groups such as a methylthio group, an ethylthio group, a propylthio group, a hexylthio group, a cyclohexylthio group, a heptylthio group, an octylthio group, a nonylthio group, and a decylthio group; arylthio groups such as a phenylthio group and a benzylthio group; a sulfo group; and a sulfur atom bridging the ring ^Z3 and the ring ^R4 described later, and a sulfonyl group.

Examples of the silicon atom having a substituent of R ⁷ or R ⁸ include a silyl group, a monomethylsilyl group, a dimethylsilyl group, a trimethylsilyl group, a triethylsilyl group; and a silicon atom forming a bridge structure between the ring Z ³ and the ring R ⁴ described below.

Examples of the halogen atom for R ⁷ and R ⁸ include a chlorine atom, a bromine atom, and a fluorine atom.

When at least two groups of ^R7 and/or ^R8 are bonded to each other to form a ring, examples include the following.
(1) Adjacent ^R7 and ^R7 are bonded to each other to form a fused ring fused to ring ^Z3 .
(2) Adjacent ^R8 and ^R8 are bonded to each other to form a fused ring fused to ring ^Z4 .
(3) ^R7 and ^R8 are bonded to form a bridge structure between ring ^Z3 and ring ^Z4 .
Specific examples of the above case (3) include a bridge structure in which a carbon atom on ring ^Z3 and a carbon atom on ring ^Z4 are linked by -O-, -S-, -SO ₂ -, -Si-, -SiH ₂ -, -SiMe ₂ -, or -SiEt ₂ -.

Of these, R ⁷ and R ⁸ are preferably a methyl group, a cyclohexyl group, a phenyl group, or a naphthyl group, more preferably a methyl group, a cyclohexyl group, or a phenyl group, still more preferably a methyl group or a phenyl group, and particularly preferably a methyl group.

Each of f and g independently represents an integer of 0 or more. Of these, each of f and g independently represents an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0.

From this viewpoint, X in the formula (1) is preferably any one selected from the group consisting of divalent groups represented by the following formulas (7) to (9) (the marks * in the formulas (7) to (9) indicate the bonding sites with the rings Z ¹ and Z ² in the formula (1). In addition, in the formulas (7) to (9), the benzene ring or the fluorene ring may have a substituent).

X is preferably a divalent group represented by the formula (2). When X is a divalent group represented by the formula (2), the aromatic polycarbonate resin of the present invention has little coloration, which is advantageous for using the resin as a raw material for a molding material.

Specific examples of more preferred carbonate structural units (A) include structural units represented by the following formulas (10) to (14), of which structural units represented by formulas (10), (11), (12), and (14) are more preferred, and structural units represented by formula (10) are even more preferred.

The carbonate structural unit (A) in the aromatic polycarbonate resin of the present invention is obtained by polymerization using an aromatic dihydroxy compound as a raw material and a carbonate-forming compound or carbonate ester described below.

The aromatic dihydroxy compound used as the raw material may be, for example, an aromatic dihydroxy compound represented by the following formula (15).

(In formula (15), the definitions and preferred examples of Z ¹ , Z ² , R ¹ , R ² , X, a and b are the same as those in formula (1).)

Specific examples of aromatic dihydroxy compounds necessary to form the carbonate structural unit (A) include, but are not limited to, aromatic dihydroxy compounds represented by the following formulas (16) to (19). Among these, aromatic dihydroxy compounds represented by formulas (16) and (17) are more preferred because they tend to improve the thermal stability of the resin, but aromatic dihydroxy compounds represented by formulas (18) and (19) may be included in any proportion.

(In formulas (16) to (19), the definitions and preferred examples of R ¹ , R ² , X, a and b are the same as those in formula (1).)

From this viewpoint, specific examples of the aromatic dihydroxy compound necessary for forming the more preferable carbonate structural unit (A) are as follows:
1,1-bis(4-hydroxyphenyl)-1-phenylethane,
1,1-bis(4-hydroxy-3-methylphenyl)-1-phenylethane,
1,1-bis(4-hydroxy-3-phenylphenyl)-1-phenylethane,
bis(4-hydroxyphenyl)diphenylmethane,
Bis(4-hydroxy-3-methylphenyl)diphenylmethane,
Bis(4-hydroxy-3-phenylphenyl)diphenylmethane,
bis(4-hydroxyphenyl)phenylmethane,
9,9-bis(4-hydroxyphenyl)fluorene,
9,9-bis(4-hydroxy-3-methylphenyl)fluorene,
9,9-bis(4-hydroxy-3-ethylphenyl)fluorene,
9,9-bis(4-hydroxy-2-methylphenyl)fluorene,
6,6'-(9H-fluorene-9,9-diyl)bis(2-naphthol).

These aromatic dihydroxy compounds may be used alone or in combination of two or more.

Among the aromatic dihydroxy compounds for forming the carbonate structural unit (A), 1,1-bis(4-hydroxyphenyl)-1-phenylethane (hereinafter abbreviated as BisAP), bis(4-hydroxyphenyl)diphenylmethane (hereinafter abbreviated as BisBP), 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinafter abbreviated as BCF), and 6,6'-(9H-fluorene-9,9-diyl)bis(2-naphthol) (hereinafter abbreviated as BNF) are preferable.
If the aromatic dihydroxy compound used as the raw material of the carbonate structural unit (A) is selected from BisAP, BisBP, BCF, and BNF, the balance between the ease of use of the aromatic dihydroxy compound in terms of both safety and cost and the refractive index of the resulting aromatic polycarbonate resin is good. Furthermore, since the aromatic polycarbonate resin is less colored, BisAP, BisBP, and BCF are more preferable, and BisAP is particularly preferable.

<Carbonate structural unit (B)>
The carbonate structural unit (B) is a structural unit represented by the following formula (5).

(In formula (5), R ⁹ and R ¹⁰ each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom. h and i each independently represent an integer of 0 to 4. When h and i are 2 or more and there are a plurality of R ^{9 s} and R ^{10 s} , the plurality of R ^{9 s} and R ^{10 s} may be the same as or different from each other. In addition, at least two groups among the plurality of R ^{9 s} and/or R ^{10 s} may be bonded to each other to form a ring. R ¹¹ and R ¹² each independently represent a hydrogen atom or an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms. However, the total number of carbon atoms of R ¹¹ and R ¹² is 11 or more and 40 or less.)

In the aromatic polycarbonate resin of the present invention, the content ratio of the carbonate structural unit (B) is not particularly limited, but when the total number of moles of all the carbonate structural units constituting the resin is taken as 100 mol%, the content of the carbonate structural unit (B) is preferably more than 0 mol% and not more than 60 mol%, more preferably 0.1 mol% to 40 mol%, even more preferably 0.5 mol% to 28 mol%, particularly preferably 1 mol% to 19 mol%, and most preferably 2 mol% to 10 mol%.

If the content ratio of the carbonate structural unit (B) is below the upper limit, the refractive index of the aromatic polycarbonate resin of the present invention is high, which is advantageous when used as an optical molding material. If the content ratio of the carbonate structural unit (B) is below the upper limit, the birefringence of the aromatic polycarbonate resin of the present invention is small, which is advantageous when used as an optical molding material. Furthermore, if the content ratio of the carbonate structural unit (B) is below the upper limit, the heat resistance, i.e., Tg, of the aromatic polycarbonate resin of the present invention is high, which is advantageous when used as a molding material.
On the other hand, when the content of the carbonate structural unit (B) is more than the above lower limit, the aromatic polycarbonate resin of the present invention has high molding flowability, which is advantageous when used as a molding material.

In the formula (5), R ¹¹ and R ¹² each independently represent a hydrogen atom or an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, provided that the total number of carbon atoms in R ¹¹ and R ¹² is 11 or more and 40 or less.

In the aromatic polycarbonate resin of the present invention, it is essential that the carbonate structural unit (B) has, in R ¹¹ and R ¹² , a long-chain aliphatic chain substituent whose total carbon number is 11 to 40. By containing a carbonate structural unit (B) having such a long-chain aliphatic chain substituent, the Tg of the aromatic polycarbonate resin of the present invention can be adjusted so as not to be too high, and further the melt fluidity of the resin can be improved and the birefringence of the molding material can be reduced.
When the total number of carbon atoms of R ¹¹ and R ¹² is 11 or more, the effect of adjusting Tg and the effect of improving melt fluidity per carbonate structural unit (B) are high, the amount of carbonate structural unit (B) introduced into the aromatic polycarbonate resin of the present invention can be reduced, and the high heat resistance and high refractive index of the resin derived from the carbonate structural unit (A) can be maintained.

On the other hand, the total carbon number of R ¹¹ and R ¹² of the carbonate structural unit (B) is 40 or less. If the long chain aliphatic chain substituent of R ¹¹ and R ¹² is too long, the heat resistance and mechanical strength are significantly reduced, and the crystallization property of the long chain aliphatic chain substituent increases, which is undesirable because it may impair the transparency of the aromatic polycarbonate resin of the present invention. From this viewpoint, the total carbon number of R ¹¹ and R ¹² is preferably 38 or less, more preferably 30 or less, even more preferably 20 or less, even more preferably 15 or less, even more preferably 13 or less, and particularly preferably 11 or less.
That is, the total number of carbon atoms of R ¹¹ and R ¹² is preferably 11.

In the carbonate structural unit (B), it is preferable that one of R ¹¹ and R ¹² is a hydrogen atom and the other is an alkyl group having 11 to 40 carbon atoms, and it is more preferable that one is a hydrogen atom and the other is an alkyl group having 11 to 19 carbon atoms. When one of R ¹¹ and R ¹² is a hydrogen atom, the flow improving effect and the birefringence reducing effect are more easily obtained, and an extreme decrease in heat resistance can be prevented.

The above-mentioned alkyl group having 11 to 19 carbon atoms includes linear and branched alkyl groups, and alkyl groups having a partial ring structure. Among them, linear and branched alkyl groups are preferred because they can more effectively increase the fluidity of the aromatic polycarbonate resin of the present invention.

Specific examples of linear alkyl groups include n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, and n-nonadecyl groups, with n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, and n-hexadecyl being preferred, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, and n-pentadecyl being more preferred, n-undecyl, n-dodecyl, n-tridecyl, and n-tetradecyl being even more preferred, n-undecyl, n-dodecyl, n-tridecyl, and n-tetradecyl being even more preferred, n-undecyl, n-dodecyl, n-tridecyl, and n-tetradecyl being particularly preferred, and n-undecyl being the most preferred. By having such an alkyl group, the aromatic polycarbonate resin of the present invention can improve melt fluidity while maintaining its high heat resistance, high refractive index, and mechanical strength, and can more effectively reduce the birefringence of the molded product.

Specific examples of the branched alkyl group include a methyldecyl group, a methylundecyl group, a methyldodecyl group, a methyltridecyl group, a methyltetradecyl group, a methylpentadecyl group, a methylhexadecyl group, a methylheptadecyl group, a methyloctadecyl group, a dimethylnonyl group, a dimethyldecyl group, a dimethylundecyl group, a dimethyldodecyl group, a dimethyltridecyl group, a dimethyltetradecyl group, a dimethylpentadecyl group, a dimethylhexadecyl group, a dimethylheptadecyl group, a trimethyloctyl group, a trimethylnonyl group, a trimethyldecyl group, a trimethylundecyl group, a trimethyldodecyl group, a trimethyltridecyl group, a trimethyltetradecyl group, a trimethyl ... Examples of the aryl group include butyl groups, trimethylhexadecyl groups, ethylnonyl groups, ethyldecyl groups, ethylundecyl groups, ethyldodecyl groups, ethyltridecyl groups, ethyltetradecyl groups, ethylpentadecyl groups, ethylhexadecyl groups, ethylheptadecyl groups, propyloctyl groups, propylnonyl groups, propyldecyl groups, propylundecyl groups, propyldodecyl groups, propyltridecyl groups, propyltetradecyl groups, propylpentadecyl groups, propylhexadecyl groups, butylheptyl groups, butyloctyl groups, butylnonyl groups, butyldecyl groups, butylundecyl groups, butyldodecyl groups, butyltridecyl groups, butyltetradecyl groups, and butylpentadecyl groups.
In the above examples of branched alkyl groups, the branching position is optional.

R ⁹ and R ¹⁰ are each independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom, provided that at least two groups of R ⁹ and/or R ¹⁰ may be bonded to each other to form a ring.

In the above, the substituent is not particularly limited as long as it does not interfere with the effects of the present invention, but is preferably selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

The unsubstituted or substituted alkyl group having 1 to 10 carbon atoms for R ⁹ and R ¹⁰ may be linear, branched or cyclic. Examples of the unsubstituted or substituted alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an n-hexyl group, a cyclohexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group and an n-decyl group.

Examples of the unsubstituted or substituted aryl group having 6 to 10 carbon atoms for R ⁹ and R ¹⁰ include unsubstituted phenyl and naphthyl groups. Substituted groups include methylphenyl (tolyl), ethylphenyl, propylphenyl, butylphenyl, dimethylphenyl, and trimethylphenyl groups. From the viewpoint of the thermal stability and heat resistance of the aromatic polycarbonate resin of the present invention, unsubstituted groups are preferred.

Examples of the unsubstituted or substituted acyl group having 1 to 10 carbon atoms for R ⁹ and R ¹⁰ include a methanoyl group, an ethanoyl group, a propanoyl group, a butanoyl group, a pentanoyl group, a hexanoyl group, a heptanoyl group, an octanoyl group, a nonanoyl group, a decanoyl group, a benzoyl group, an acrylyl group, a chloroethanoyl group, a dichloroethanoyl group, a trichloroethanoyl group, a bromoethanoyl group, and a fluoroethanoyl group.

Examples of the oxygen atom having a substituent of R ⁹ or R ¹⁰ include a hydroxy group; an alkoxy group such as a methoxy group, an ethoxy group, a propyloxy group, a hexyloxy group, a cyclohexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, a phenoxy group, or a benzyloxy group; and an oxygen atom forming a bridge structure connecting two benzene rings in the formula (5) described later.

Examples of the sulfur atom having a substituent of R ⁹ or R ¹⁰ include a thiol group; alkylthio groups such as a methylthio group, an ethylthio group, a propylthio group, a hexylthio group, a cyclohexylthio group, a heptylthio group, an octylthio group, a nonylthio group, and a decylthio group; arylthio groups such as a phenylthio group and a benzylthio group; a sulfo group; and a sulfur atom forming a crosslinking structure connecting two benzene rings in the formula (5) described later, and a sulfonyl group.

Examples of the silicon atom having a substituent of R ⁹ or R ¹⁰ include a silyl group, a monomethylsilyl group, a dimethylsilyl group, a trimethylsilyl group, a triethylsilyl group; and a silicon atom forming a cross-linked structure connecting two benzene rings in the formula (5) described later.

Examples of the halogen atom for R ⁹ and R ¹⁰ include a chlorine atom, a bromine atom, and a fluorine atom.

When at least two groups of R ⁹ and/or R ¹⁰ are bonded to each other to form a ring, examples include the following.
(1) Adjacent R ⁹ and R ⁹ are bonded to each other to form a fused ring fused to a benzene ring.
(2) Adjacent R ¹⁰ and R ¹⁰ are bonded to each other to form a fused ring fused to a benzene ring.
(3) R ⁹ and R ¹⁰ combine to form a bridge structure connecting the two benzene rings in formula (5).
Specific examples of the above case (3) include crosslinked structures linking carbon atoms on two benzene rings together, such as -O-, -S-, -SO ₂ -, -Si-, -SiH ₂ -, -SiMe ₂ -, or -SiEt ₂ -.

Of these, R ⁹ and R ¹⁰ are preferably a methyl group, a cyclohexyl group, a phenyl group, or a naphthyl group, more preferably a methyl group, a cyclohexyl group, or a phenyl group, still more preferably a methyl group or a phenyl group, and particularly preferably a methyl group.

Each of h and i independently represents an integer from 0 to 4. Of these, each of h and i independently represents an integer from 0 to 2, more preferably 0 or 1, and even more preferably 0.

Specific examples of such carbonate structural units (B) include structural units represented by the following formulas (20) to (27). Among these, structural units represented by formulas (20) to (26) are preferred, structural units represented by formulas (20) to (25) are more preferred, structural units represented by formulas (20) to (24) are even more preferred, structural units represented by formulas (20) to (23) are particularly preferred, and structural units represented by formula (20) are most preferred.

Specific examples of more preferred carbonate structure (B) include structural units represented by the following formulae (6), (28) to (34), because they improve the thermal stability of the aromatic polycarbonate resin of the present invention. Among these, structural units represented by formulae (6), (28) to (32) are preferred, structural units represented by formulae (6), (28) to (31) are more preferred, structural units represented by formulae (6), (28) to (30) are even more preferred, structural units represented by formulae (6), (28), and (29) are particularly preferred, and structural units represented by formula (6) are most preferred.

The carbonate structural unit (B) in the aromatic polycarbonate resin of the present invention is obtained by polymerization using an aromatic dihydroxy compound as a raw material and a carbonate-forming compound or carbonate ester described below.

The aromatic dihydroxy compound used as the raw material may be, for example, an aromatic dihydroxy compound represented by the following formula (35).

(In formula (35), the definitions and preferred examples of R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , h and i are the same as those in formula (5).)

More preferred specific examples of the aromatic dihydroxy compound necessary for forming the carbonate structural unit (B) include the following.
1,1-bis(4-hydroxyphenyl)dodecane,
1,1-bis(2-hydroxyphenyl)dodecane,
1-(2-hydroxyphenyl)-1-(4-hydroxyphenyl)dodecane,
1,1-bis(4-hydroxyphenyl)tridecane,
1,1-bis(2-hydroxyphenyl)tridecane,
1-(2-hydroxyphenyl)-1-(4-hydroxyphenyl)tridecane,
1,1-bis(4-hydroxyphenyl)tetradecane,
1,1-bis(2-hydroxyphenyl)tetradecane,
1-(2-hydroxyphenyl)-1-(4-hydroxyphenyl)tetradecane,
1,1-bis(4-hydroxyphenyl)pentadecane,
1,1-bis(2-hydroxyphenyl)pentadecane,
1-(2-hydroxyphenyl)-1-(4-hydroxyphenyl)pentadecane,
1,1-bis(4-hydroxyphenyl)hexadecane,
1,1-bis(2-hydroxyphenyl)hexadecane,
1-(2-hydroxyphenyl)-1-(4-hydroxyphenyl)hexadecane,
1,1-bis(4-hydroxyphenyl)heptadecane,
1,1-bis(2-hydroxyphenyl)heptadecane,
1-(2-hydroxyphenyl)-1-(4-hydroxyphenyl)heptadecane,
1,1-bis(4-hydroxyphenyl)octadecane,
1,1-bis(2-hydroxyphenyl)octadecane,
1-(2-hydroxyphenyl)-1-(4-hydroxyphenyl)octadecane,
1,1-bis(4-hydroxyphenyl)nonadecane,
1,1-bis(2-hydroxyphenyl)nonadecane,
1-(2-hydroxyphenyl)-1-(4-hydroxyphenyl)nonadecane,

1,1-bis(3-methyl-4-hydroxyphenyl)dodecane,
1,1-bis(2-hydroxy-3-methylphenyl)dodecane,
1-(2-hydroxy-3-methyl-phenyl)-1-(3-methyl-4-hydroxyphenyl)dodecane,
1,1-bis(3-methyl-4-hydroxyphenyl)tridecane,
1,1-bis(2-hydroxy-3-methylphenyl)tridecane,
1-(2-hydroxy-3-methyl-phenyl)-1-(3-methyl-4-hydroxyphenyl)tridecane,
1,1-bis(3-methyl-4-hydroxyphenyl)tetradecane,
1,1-bis(2-hydroxy-3-methylphenyl)tetradecane,
1-(2-hydroxy-3-methyl-phenyl)-1-(3-methyl-4-hydroxyphenyl)tetradecane,
1,1-bis(3-methyl-4-hydroxyphenyl)pentadecane,
1,1-bis(2-hydroxy-3-methylphenyl)pentadecane,
1-(2-hydroxy-3-methyl-phenyl)-1-(3-methyl-4-hydroxyphenyl)pentadecane,
1,1-bis(3-methyl-4-hydroxyphenyl)hexadecane,
1,1-bis(2-hydroxy-3-methylphenyl)hexadecane,
1-(2-hydroxy-3-methyl-phenyl)-1-(3-methyl-4-hydroxyphenyl)hexadecane,
1,1-bis(3-methyl-4-hydroxyphenyl)heptadecane,
1,1-bis(2-hydroxy-3-methylphenyl)heptadecane,
1-(2-hydroxy-3-methyl-phenyl)-1-(3-methyl-4-hydroxyphenyl)heptadecane,
1,1-bis(3-methyl-4-hydroxyphenyl)octadecane,
1,1-bis(2-hydroxy-3-methylphenyl)octadecane,
1-(2-hydroxy-3-methyl-phenyl)-1-(3-methyl-4-hydroxyphenyl)octadecane,

1,1-bis(3-methyl-4-hydroxyphenyl)nonadecane,
1,1-bis(2-hydroxy-3-methylphenyl)nonadecane,
1-(2-hydroxy-3-methyl-phenyl)-1-(3-methyl-4-hydroxyphenyl)nonadecane,
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)dodecane,
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)tridecane,
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)tetradecane,
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)pentadecane,
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)hexadecane,
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)heptadecane,
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)octadecane,
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)nonadecane,
1,1-bis(3-ethyl-4-hydroxyphenyl)dodecane,
1,1-bis(3-ethyl-4-hydroxyphenyl)tridecane,
1,1-bis(3-ethyl-4-hydroxyphenyl)tetradecane,
1,1-bis(3-ethyl-4-hydroxyphenyl)pentadecane,
1,1-bis(3-ethyl-4-hydroxyphenyl)hexadecane,
1,1-bis(3-ethyl-4-hydroxyphenyl)heptadecane,
1,1-bis(3-ethyl-4-hydroxyphenyl)octadecane,
1,1-bis(3-ethyl-4-hydroxyphenyl)nonadecane,
1,1-bis(3-propyl-4-hydroxyphenyl)dodecane,
1,1-bis(3-propyl-4-hydroxyphenyl)tridecane,
1,1-bis(3-propyl-4-hydroxyphenyl)tetradecane,
1,1-bis(3-propyl-4-hydroxyphenyl)pentadecane,
1,1-bis(3-propyl-4-hydroxyphenyl)hexadecane,
1,1-bis(3-propyl-4-hydroxyphenyl)heptadecane,
1,1-bis(3-propyl-4-hydroxyphenyl)octadecane,
1,1-bis(3-propyl-4-hydroxyphenyl)nonadecane,

1,1-bis(3-butyl-4-hydroxyphenyl)dodecane,
1,1-bis(3-butyl-4-hydroxyphenyl)tridecane,
1,1-bis(3-butyl-4-hydroxyphenyl)tetradecane,
1,1-bis(3-butyl-4-hydroxyphenyl)pentadecane,
1,1-bis(3-butyl-4-hydroxyphenyl)hexadecane,
1,1-bis(3-butyl-4-hydroxyphenyl)heptadecane,
1,1-bis(3-butyl-4-hydroxyphenyl)octadecane,
1,1-bis(3-butyl-4-hydroxyphenyl)nonadecane,
1,1-bis(3-nonyl-4-hydroxyphenyl)dodecane,
1,1-bis(3-nonyl-4-hydroxyphenyl)tridecane,
1,1-bis(3-nonyl-4-hydroxyphenyl)tetradecane,
1,1-bis(3-nonyl-4-hydroxyphenyl)pentadecane,
1,1-bis(3-nonyl-4-hydroxyphenyl)hexadecane,
1,1-bis(3-nonyl-4-hydroxyphenyl)heptadecane,
1,1-bis(3-nonyl-4-hydroxyphenyl)octadecane,
1,1-bis(3-nonyl-4-hydroxyphenyl)nonadecane.

These aromatic dihydroxy compounds may be used alone or in combination of two or more.

As the aromatic dihydroxy compound necessary for forming the carbonate structural unit (B) of the aromatic polycarbonate resin of the present invention, from the viewpoints of the thermal stability of the aromatic polycarbonate resin and the ease of availability of the aromatic dihydroxy compound, the following aromatic dihydroxy compounds are particularly preferred:
1,1-bis(4-hydroxyphenyl)dodecane,
1,1-bis(4-hydroxyphenyl)tridecane,
1,1-bis(4-hydroxyphenyl)tetradecane,
1,1-bis(4-hydroxyphenyl)pentadecane,
1,1-bis(4-hydroxyphenyl)hexadecane,
1,1-bis(4-hydroxyphenyl)heptadecane,
1,1-bis(4-hydroxyphenyl)nonadecane,
is preferred,
1,1-bis(4-hydroxyphenyl)dodecane,
1,1-bis(4-hydroxyphenyl)tridecane,
1,1-bis(4-hydroxyphenyl)tetradecane,
1,1-bis(4-hydroxyphenyl)pentadecane,
1,1-bis(4-hydroxyphenyl)hexadecane,
is more preferred,
1,1-bis(4-hydroxyphenyl)dodecane,
1,1-bis(4-hydroxyphenyl)tridecane,
1,1-bis(4-hydroxyphenyl)tetradecane,
1,1-bis(4-hydroxyphenyl)pentadecane,
is more preferred,
1,1-bis(4-hydroxyphenyl)dodecane,
1,1-bis(4-hydroxyphenyl)tridecane,
1,1-bis(4-hydroxyphenyl)tetradecane,
is particularly preferred,
1,1-bis(4-hydroxyphenyl)dodecane is most preferred.

<Other structural units>
The aromatic polycarbonate resin of the present invention may contain structural units other than the carbonate structural unit (A) and the carbonate structural unit (B) (hereinafter, these may be referred to as "other structural units"), and examples of monomers that form the other structural units in the resin include dihydroxy compounds and diester compounds containing an aromatic component. Among these, dihydroxy compounds containing an aromatic component are preferred from the viewpoint of increasing the reaction efficiency.

(Dihydroxy Compounds Containing Aromatic Components)
As the dihydroxy compound containing an aromatic component, for example, the following dihydroxy compounds can be used.
2,2-bis(4-hydroxyphenyl)propane,
2,2-bis(3-methyl-4-hydroxyphenyl)propane,
2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane,
2,2-bis(4-hydroxy-3,5-diethylphenyl)propane,
2,2-bis(4-hydroxy-(3-phenyl)phenyl)propane,
2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane,
2,2-bis(4-hydroxy-3,5-dibromophenyl)propane,
bis(4-hydroxyphenyl)methane,
1,1-bis(4-hydroxyphenyl)ethane,
2,2-bis(4-hydroxyphenyl)butane,
2,2-bis(4-hydroxyphenyl)pentane,
1,1-bis(4-hydroxyphenyl)-2-ethylhexane,
1,1-bis(4-hydroxyphenyl)decane,
bis(4-hydroxy-3-nitrophenyl)methane,
3,3-bis(4-hydroxyphenyl)pentane,
1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene,
1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene,
2,2-bis(4-hydroxyphenyl)hexafluoropropane,
1,1-bis(4-hydroxyphenyl)cyclohexane,
bis(4-hydroxyphenyl)sulfone,
2,4'-dihydroxydiphenyl sulfone,
bis(4-hydroxyphenyl)sulfide,
Bis(4-hydroxy-3-methylphenyl)sulfide,
bis(4-hydroxyphenyl)disulfide,
4,4'-dihydroxydiphenyl ether,
4,4'-dihydroxy-3,3'-dichlorodiphenyl ether,
6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane,
7,7'-dimethyl-6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane,
Aromatic bisphenol compounds such as 9,9-bis(2-hydroxynaphthyl)fluorene;
2,2-bis(4-(2-hydroxyethoxy)phenyl)propane,
2,2-bis(4-(2-hydroxypropoxy)phenyl)propane,
1,3-bis(2-hydroxyethoxy)benzene,
4,4'-bis(2-hydroxyethoxy)biphenyl,
Bis(4-(2-hydroxyethoxy)phenyl)sulfone,
9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene,
9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene,
Dihydroxy compounds having an ether group bonded to an aromatic group, such as 9,9-bis(2-(2-hydroxyethoxy)naphthyl)fluorene:

However, since dihydroxy compounds having an ether group bonded to an aromatic group and carbonate structural units derived from carbonate-forming compounds or carbonate esters described below reduce the thermal stability of the resin, it is preferable to use a smaller amount of dihydroxy compounds having an ether group bonded to an aromatic group.

As a dihydroxy compound containing an aromatic component that forms other structural units, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) is preferred in terms of the balance between heat resistance and raw material cost.

(Diester Compound)
As the diester compound, for example, the following dicarboxylic acids can be used.
Aromatic dicarboxylic acids such as terephthalic acid, phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid;
Alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and decalin-2,6-dicarboxylic acid; aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid;
In addition, these dicarboxylic acid components can be used as raw materials for polyester carbonate as dicarboxylic acid itself, but depending on the production method, dicarboxylic acid esters such as methyl esters and phenyl esters, and dicarboxylic acid derivatives such as dicarboxylic acid halides can also be used as raw materials. Since the polymerization reactivity of diester compounds is relatively low, from the viewpoint of increasing the reaction efficiency, it is preferable to use less other diester compounds, except for carbonate esters and diester compounds having an oligofluorene structure unit.

The dihydroxy compounds and diester compounds for forming the other structural units may be used alone or in combination of two or more depending on the required performance of the resulting resin. The content of the other structural units in the resin is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 20% by mass or less, when the total mass of all structural units and linking groups constituting the aromatic polycarbonate resin is taken as 100% by mass. The other structural units mainly play a role in adjusting the heat resistance of the resin and imparting flexibility and toughness, but if the content is too high, there is a risk of deterioration in heat resistance and optical properties.

<Characteristics of aromatic polycarbonate resin>
The aromatic polycarbonate resin of the present invention contains the carbonate structural unit (A) in an appropriate ratio, thereby improving heat resistance, improving refractive index, and reducing birefringence, and contains the carbonate structural unit (B) in an appropriate ratio, thereby improving melt fluidity and reducing birefringence of molded products while maintaining high heat resistance and high refractive index. Furthermore, since the aromatic polycarbonate resin of the present invention does not have a carbonate bond derived from an aliphatic hydroxy compound as its main skeleton, it has high thermal stability and can be produced or injection molded at high temperatures.

The aromatic polycarbonate resin of the present invention has a high glass transition temperature (Tg) and is excellent in heat resistance. The Tg of the aromatic polycarbonate resin is preferably 150°C or higher, more preferably 160°C or higher.

On the other hand, from the viewpoint of ensuring good moldability, the Tg of the aromatic polycarbonate resin of the present invention is preferably 250°C or less, more preferably 230°C or less, and even more preferably 200°C or less.

The aromatic polycarbonate resin of the present invention contains carbonate structural units (A) and carbonate structural units (B) in the above-mentioned preferred ranges, so that the glass transition temperature can be easily adjusted to a range that achieves both high heat resistance and good moldability. Therefore, the aromatic polycarbonate resin of the present invention is also suitable for applications that are expected to be exposed to high-temperature environments, such as in-vehicle optical lenses.

The glass transition temperature (Tg) of the aromatic polycarbonate resin is measured by the method described in the Examples section below.

The aromatic polycarbonate resin of the present invention preferably has a melt viscosity of 20 to 1000 Pa·s, more preferably 40 to 500 Pa·s, as measured using a capillary rheometer at 300° C. and 1216 s ⁻¹ in accordance with JIS K 7199 (1999 edition). When the melt viscosity is equal to or higher than the lower limit, the mechanical properties of the molded article made of the aromatic polycarbonate resin of the present invention are good. When the melt viscosity is equal to or lower than the upper limit, the flowability and moldability of the aromatic polycarbonate resin of the present invention are good, and the birefringence of the obtained molded article tends to be reduced.

The melt viscosity of the aromatic polycarbonate resin is measured by the method described in the Examples section below.

The molecular weight of the aromatic polycarbonate resin of the present invention is preferably 5,000 to 50,000, in terms of viscosity average molecular weight (Mv) calculated from the solution viscosity. If the viscosity average molecular weight is equal to or greater than the lower limit, the mechanical properties of the molded article made of the aromatic polycarbonate resin of the present invention will be good. If the viscosity average molecular weight is equal to or less than the upper limit, the flowability and moldability of the aromatic polycarbonate resin of the present invention will tend to be good. From this perspective, the viscosity average molecular weight (Mv) of the aromatic polycarbonate resin of the present invention is more preferably 6,000 to 30,000.

The viscosity average molecular weight (Mv) of the aromatic polycarbonate resin of the present invention means a value calculated from the Schnell viscosity formula, i.e., η = 1.23 × 10 ^-4 Mv ^0.83 , by determining the intrinsic viscosity (limiting viscosity) [η] (unit: dL/g) at a temperature of 20°C using methylene chloride as a solvent and an Ubbelohde viscometer. The intrinsic viscosity (limiting viscosity) [η] is a value calculated from ^{the following formula} , by measuring the specific viscosity [η _sp ] at each solution concentration [C] (g/dL).

The refractive index ( _nD ) of the aromatic polycarbonate resin of the present invention at a wavelength of 589 nm and a temperature of 20°C is, for example, 1.600 or more, preferably 1.600 or more and 1.700 or less, and more preferably 1.610 or more and 1.680 or less. If the refractive index is 1.600 or more, the added value of the resin is high when used as an optical material such as a lens. In order to obtain an aromatic polycarbonate resin having a refractive index exceeding 1.700, it is necessary to form a structural unit having a high refractive index other than the carbonate structural unit (A) and the carbonate structural unit (B) in the aromatic polycarbonate resin of the present invention, and there is a risk that the Tg of the resin becomes excessively high, the thermal stability of the resin decreases, or mold contamination increases.

The Abbe number (ν _D ) of the aromatic polycarbonate resin of the present invention at a temperature of 20° C. is, for example, 35.0 or less, preferably 15.0 or more and 35.0 or less, and more preferably 16.0 or more and 32.0 or less. If the Abbe number is small, the aromatic polycarbonate resin is useful as a material for an aberration correcting low Abbe number concave lens to be used in combination with a high Abbe number convex lens such as a COP (cycloolefin polymer).

Here, the refractive index is rounded off to the fourth decimal place, and the Abbe number is rounded off to the first decimal place. The refractive index and Abbe number of aromatic polycarbonate resin are measured by the method described in the Examples section below.

The 5% thermal weight loss temperature (Td) of the aromatic polycarbonate resin of the present invention is preferably 350°C or higher, more preferably 400°C or higher, and even more preferably 410°C or higher. The higher the 5% thermal weight loss temperature, the higher the thermal stability and the higher the endurance for use at high temperatures. In addition, the manufacturing temperature can be increased, allowing for a wider range of control during manufacturing, making manufacturing easier. On the other hand, the lower the 5% thermal weight loss temperature, the lower the thermal stability and the more difficult it is to use at high temperatures. In addition, the narrower the allowable range of control during manufacturing, making manufacturing more difficult. There is no particular limit to the upper limit of the 5% thermal weight loss temperature.

The 5% thermal weight loss temperature of aromatic polycarbonate resin is measured by the method described in the Examples section below.

[Method for producing aromatic polycarbonate resin]
The aromatic polycarbonate resin of the present invention can be produced by a conventionally known polymerization method, and the polymerization method is not particularly limited.Examples of the polymerization method include interfacial polymerization method, melt transesterification method, pyridine method, ring-opening polymerization method of cyclic carbonate compound, solid-phase transesterification method of prepolymer, etc.The following will specifically explain the particularly suitable method among these methods.

<Interfacial Polymerization Method>
In the interfacial polymerization method, a dihydroxy compound as a raw material and a carbonate-forming compound are reacted in the presence of an organic solvent inert to the reaction and an aqueous alkali solution, usually at a pH of 9 or more, and then interfacial polymerization is carried out in the presence of a polymerization catalyst to obtain a polycarbonate resin. Note that a molecular weight regulator (terminal terminator) may be present in the reaction system as necessary, and an antioxidant may be present to prevent oxidation of the dihydroxy compound as a raw material.

The organic solvent inert to the reaction is not particularly limited, but examples thereof include chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane, chloroform, monochlorobenzene, and dichlorobenzene; aromatic hydrocarbons such as benzene, toluene, and xylene; and the like. Note that one type of organic solvent may be used, or two or more types may be used in any combination and ratio.

The alkaline compound contained in the alkaline aqueous solution is not particularly limited, but examples thereof include alkali metal compounds and alkaline earth metal compounds such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and sodium hydrogen carbonate. Among these, sodium hydroxide and potassium hydroxide are preferred. The alkaline compounds may be used alone or in any combination and ratio of two or more.

There is no limit to the concentration of the alkaline compound in the alkaline aqueous solution, but the alkaline compound concentration is usually 5 to 10 mass % in order to control the pH of the alkaline aqueous solution to 10 to 12. In addition, for example, when blowing in phosgene, in order to control the pH of the aqueous phase to 10 to 12, preferably 10 to 11, it is preferable that the molar ratio of the raw material dihydroxy compound to the alkaline compound is usually 1:1.9 or more, preferably 1:2.0 or more, and usually 1:3.2 or less, preferably 1:2.5 or less.

By using a dihydroxy compound containing both the aromatic dihydroxy compound necessary to form the aforementioned carbonate structural unit (A) and the aromatic dihydroxy compound necessary to form the carbonate structural unit (B) as the raw dihydroxy compound, the aromatic polycarbonate resin of the present invention having the carbonate structural unit (A) and the carbonate structural unit (B) can be produced.

As the carbonate-forming compound, carbonyl halides are preferably used, and among these, phosgene is preferably used, and the method using phosgene is specifically called the phosgene method.

The polymerization catalyst is not particularly limited, but examples thereof include aliphatic tertiary amines such as trimethylamine, triethylamine, tributylamine, tripropylamine, and trihexylamine; alicyclic tertiary amines such as N,N'-dimethylcyclohexylamine and N,N'-diethylcyclohexylamine; aromatic tertiary amines such as N,N'-dimethylaniline and N,N'-diethylaniline; quaternary ammonium salts such as trimethylbenzylammonium chloride, tetramethylammonium chloride, and triethylbenzylammonium chloride; pyridine; guanine; salts of guanidine; and the like. Note that one type of polymerization catalyst may be used, or two or more types may be used in any combination and ratio.

The molecular weight regulator is not particularly limited, but examples thereof include aromatic alcohols having a monohydric phenolic hydroxyl group; aliphatic alcohols such as methanol and butanol; mercaptans; and phthalic acid imide, with aromatic alcohols being preferred.

Specific examples of such aromatic alcohols include phenol, o-n-butylphenol, m-n-butylphenol, p-n-butylphenol, o-isobutylphenol, m-isobutylphenol, p-isobutylphenol, o-t-butylphenol, m-t-butylphenol, p-t-butylphenol, o-n-pentylphenol, m-n-pentylphenol, p-n-pentylphenol, o-n-hexylphenol, m-n-hexylphenol, p-n-hexylphenol, p-t-octylphenol, o-cyclohexylphenol, m-cyclohexylphenol, p-cyclohexylphenol, o-phenylphenol, m-phenylphenol, p-phenylphenol, o-n-nonylphenol, m-n-nonylphenol, p -n-nonylphenol, o-cumylphenol, m-cumylphenol, p-cumylphenol, o-naphthylphenol, m-naphthylphenol, p-naphthylphenol, 2,5-di-t-butylphenol, 2,4-di-t-butylphenol, 3,5-di-t-butylphenol, 2,5-dicumylphenol, 3,5-dicumylphenol, p-cresol, bromophenol, tribromophenol, monoalkylphenol having a linear or branched alkyl group having an average carbon number of 12 to 35 at the ortho, meta or para position, 9-(4-hydroxyphenyl)-9-(4-methoxyphenyl)fluorene, 9-(4-hydroxy-3-methylphenyl)-9-(4-methoxy-3-methylphenyl)fluorene, 4-(1-adamantyl)phenol, etc. Among these, p-t-butylphenol, p-phenylphenol and p-cumylphenol are preferably used.

The molecular weight regulator may be used alone or in any combination and ratio of two or more kinds.

The amount of molecular weight regulator used is not particularly limited, but is, for example, usually 0.5 mol or more, preferably 1 mol or more, and usually 50 mol or less, preferably 30 mol or less, per 100 mol of the raw material dihydroxy compound. By using an amount of molecular weight regulator within this range, the thermal stability and hydrolysis resistance of the aromatic polycarbonate resin can be improved.

Antioxidants are not particularly limited, but examples include hindered phenol-based antioxidants. Specific examples thereof include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 3,3',3",5,5',5"-hexa-tert-butyl-a,a',a"-(mesitylene-2,4,6- triyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, etc.

Among these, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate are preferred. Commercially available products of such phenolic antioxidants include "Irganox 1010" and "Irganox 1076" manufactured by BASF, and "Adekastab AO-50" and "Adekastab AO-60" manufactured by ADEKA.

Other examples of antioxidants include phosphite antioxidants. Specific examples include tris(2,4-di-tert-butylphenyl)phosphite, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 2,2'-methylenebis(4,6-di-tert-butylphenyl)2-ethylphenylphosphite, tris(nonylphenyl)phosphite, tetra(C12-C15 alkyl)-4,4'-isopropylidenediphenyldiphosphite, 2-ethylhexyldiphenylphosphite, isodecyldiphenylphosphite, triisodecylphosphite, triphenylphosphite, and the like.

Among these, tris(2,4-di-tert-butylphenyl)phosphite and 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane are preferred. Commercially available products of such phosphite antioxidants include "Irgafos 168" manufactured by BASF, and "Adeka STAB 2112" and "Adeka STAB PEP-36" manufactured by ADEKA.

The antioxidant may be used alone or in any combination of two or more in any ratio.

The amount of antioxidant used is not particularly limited, but is, for example, usually 0.001 parts by mass or more, preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and usually 1 part by mass or less, preferably 0.5 parts by mass or less, per 100 parts by mass of the raw dihydroxy compound. If the amount of antioxidant used is less than the lower limit of the above range, the antioxidant effect may be insufficient, and if the amount of antioxidant used exceeds the upper limit of the above range, gas may be easily generated during injection molding.

In the reaction, the order of mixing the reaction substrate (reaction raw material), reaction solvent (organic solvent), catalyst, additives, etc. is arbitrary as long as the desired aromatic polycarbonate resin can be obtained, and an appropriate order may be set arbitrarily. For example, when phosgene is used as the carbonate-forming compound, the molecular weight modifier can be mixed at any time between the reaction of the raw material dihydroxy compound with phosgene (phosgenation) and the start of the polymerization reaction.
The reaction temperature is not particularly limited, but is usually 0 to 40° C., and the reaction time is not particularly limited, but is usually several minutes (eg, 10 minutes) to several hours (eg, 6 hours).

<Melt transesterification method>
In the melt transesterification method, for example, a transesterification reaction is carried out between a carbonate ester and a raw material dihydroxy compound.
The dihydroxy compound as the raw material is the same as that in the interfacial polymerization method. The monomers necessary for forming the other structural units are also the same as those in the interfacial polymerization method.

The carbonate ester may be, for example, a compound represented by the following formula (I), and examples thereof include aryl carbonates, dialkyl carbonates, biscarbonates of dihydroxy compounds, monocarbonates of dihydroxy compounds, and carbonates of dihydroxy compounds such as cyclic carbonates.

(In formula (I), R ²¹ and R ²² each independently represent an alkyl group, an aryl group, or an arylalkyl group having 1 to 30 carbon atoms, which may have a substituent.)

Hereinafter, when ^R21 and ^R22 are an alkyl group or an arylalkyl group, they are referred to as a dialkyl carbonate, and when they are an aryl group, they are referred to as a diaryl carbonate. In particular, from the viewpoint of reactivity with aromatic dihydroxy compounds, it is preferable that ^R21 and ^R22 are both aryl groups, and the carbonate ester is more preferably a diaryl carbonate represented by the following formula (II).

(In formula (II), R ²³ and R ²⁴ each independently represent a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 1 to 20 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and p and q each independently represent an integer of 0 to 5.)

Specific examples of such carbonate esters include dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, and di-t-butyl carbonate, diphenyl carbonate (hereinafter sometimes abbreviated as "DPC"), bis(4-methylphenyl)carbonate, bis(4-chlorophenyl)carbonate, bis(4-fluorophenyl)carbonate, bis(2-chlorophenyl)carbonate, bis(2,4-difluorophenyl)carbonate, bis(4-nitrophenyl)carbonate, bis(2-nitrophenyl)carbonate, bis(methylsalicylphenyl)carbonate, and diaryl carbonates (which may have a substituent) such as ditolyl carbonate, with diphenyl carbonate being preferred.

These carbonate esters can be used alone or in combination of two or more.

The carbonate ester may be replaced with a diester compound such as a dicarboxylic acid or a dicarboxylate ester, in which case a polyester carbonate is obtained. Since the polymerization reactivity of diester compounds is relatively low, it is preferable to use fewer other diester compounds from the viewpoint of increasing the reaction efficiency. The substitution ratio of the carbonate ester with the diester compound is preferably 50 mol % or less, more preferably 30 mol % or less. Representative diester compounds are as described above.

The ratio of the raw dihydroxy compound and the carbonate ester is arbitrary as long as the desired aromatic polycarbonate resin is obtained, but it is preferable to use these carbonate esters in excess of the raw dihydroxy compound when polymerizing with the dihydroxy compound. That is, the amount of carbonate ester used is preferably 1.01 to 1.30 times (molar ratio) the amount of the raw dihydroxy compound, and more preferably 1.02 to 1.20 times (molar ratio). If this molar ratio is too small, the terminal OH groups of the resulting aromatic polycarbonate resin will increase, and the thermal stability of the resin will tend to deteriorate. On the other hand, if this molar ratio is too large, the reaction rate of the ester exchange will decrease, making it difficult to produce an aromatic polycarbonate resin having the desired molecular weight, or the amount of carbonate ester remaining in the resin will increase, which may cause an odor during molding processing or when the resin is made into a molded product.

When producing an aromatic polycarbonate resin by the melt transesterification method, a transesterification catalyst is usually used. The transesterification catalyst is not particularly limited, and any conventionally known catalyst can be used. For example, it is preferable to use an alkali metal compound and/or an alkaline earth metal compound. In addition, a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, or an amine compound may be used as an auxiliary. Note that one type of transesterification catalyst may be used, or two or more types may be used in any combination and ratio.

In the melt transesterification method, the reaction temperature is not particularly limited, but is usually 100 to 320°C. The pressure during the reaction is not particularly limited, but is usually reduced pressure of 2 mmHg or less. The specific operation is to carry out the melt polycondensation reaction under the above conditions while removing by-products.

Here, the aromatic polycarbonate resin of the present invention is significantly affected by thermal history and oxidation in the presence of an alkaline catalyst, leading to a deterioration in color. Therefore, it is preferable to set the reaction temperature at 320°C or lower, and to select reduced pressure conditions with a lower limit of about 0.05 mmHg to prevent oxygen from leaking from the equipment due to excessive reduced pressure.

The reaction can be carried out in either a batch or continuous manner. When the reaction is carried out in a batch manner, the order in which the reaction substrate, reaction solvent, catalyst, additives, etc. are mixed can be any order as long as the desired aromatic polycarbonate resin is obtained, and any appropriate order can be set.

In the melt transesterification method, a catalyst deactivator may be used as necessary. Any compound that neutralizes the transesterification catalyst may be used as the catalyst deactivator. Examples include sulfur-containing acidic compounds and their derivatives, phosphorus-containing acidic compounds and their derivatives, etc. One type of catalyst deactivator may be used, or two or more types may be used in any combination and ratio.

The amount of catalyst deactivator used is not particularly limited, but is usually 0.5 equivalents or more, preferably 1 equivalent or more, more preferably 3 equivalents or more, and usually 50 equivalents or less, preferably 10 equivalents or less, more preferably 8 equivalents or less, relative to the transesterification catalyst. The amount of catalyst deactivator used is usually 1 ppm or more, 100 ppm or less, and preferably 50 ppm or less, relative to the aromatic polycarbonate resin.

[Aromatic polycarbonate resin composition]
The aromatic polycarbonate resin composition of the present invention is a mixture of the aromatic polycarbonate resin of the present invention and known additives and/or resins other than the aromatic polycarbonate resin of the present invention (hereinafter sometimes referred to as "other resins").

As the additive, any known additive can be used without particular limitation as long as it does not impair the excellent physical properties of the aromatic polycarbonate resin of the present invention. Examples of the additive include the various additives exemplified as additives that may be contained in the molded product of the present invention described below, and particularly, at least one selected from the group consisting of heat stabilizers, antioxidants, ultraviolet absorbers, brightness enhancers, dyes, pigments, mold release agents, flow modifiers, and impact resistance improvers.

Furthermore, the aromatic polycarbonate resin composition of the present invention may contain other resins as necessary, in addition to the aromatic polycarbonate resin of the present invention, as long as the desired physical properties are not significantly impaired. Examples of other resins include polycarbonate resins other than the aromatic polycarbonate resin of the present invention, and resins other than polycarbonate resins. Examples of polycarbonate resins other than the aromatic polycarbonate resin of the present invention include, but are not limited to, polycarbonate resins derived from bisphenol A. As such polycarbonate resins, polycarbonate resins derived from bisphenol A are preferable because they have relatively high heat resistance and refractive index and are inexpensive. Examples of resins other than polycarbonate resin include thermoplastic polyester resins such as polyethylene terephthalate resin, polytrimethylene terephthalate, and polybutylene terephthalate resin; styrene resins such as polystyrene resin, high impact polystyrene resin (HIPS), acrylonitrile-styrene copolymer (AS resin), acrylonitrile-styrene-acrylic rubber copolymer (ASA resin), and acrylonitrile-ethylene propylene rubber-styrene copolymer (AES resin); polyolefin resins such as polyethylene resin and polypropylene resin; polyamide resin; polyimide resin; polyetherimide resin; polyurethane resin; polyphenylene ether resin; polyphenylene sulfide resin; polysulfone resin; and polymethacrylate resin.

The other resins may be contained in one type or in any combination and ratio of two or more types.

[Molded body]
The molded article of the present invention can be produced by molding a material containing the aromatic polycarbonate resin of the present invention or the aromatic polycarbonate resin composition of the present invention.

The shape of the molded product of the present invention is not particularly limited, and examples include one-dimensional structures (e.g., linear, thread-like, etc.), two-dimensional structures (e.g., film-like, sheet-like, plate-like, etc.), and three-dimensional structures (e.g., concave or convex lens-like, rod-like, hollow (tubular), etc.).

The molded article of the present invention may contain various additives [for example, fillers or reinforcing agents, colorants (for example, dyes and pigments), conductive agents, flame retardants, plasticizers, lubricants, stabilizers (for example, antioxidants, ultraviolet absorbers, heat stabilizers), release agents, antistatic agents, dispersants, flow control agents, leveling agents, defoamers, surface modifiers, stress reducing agents (for example, silicone oils, silicone rubbers, various plastic powders, various engineering plastic powders, etc.), carbon materials, etc.]. These additives may be used alone or in combination of two or more.

The molded article of the present invention can be manufactured using, for example, injection molding, injection compression molding, extrusion molding, transfer molding, blow molding, pressure molding, casting molding, etc.

When the molded article of the present invention is produced by such a molding method, the maximum temperature during molding is preferably 300°C or higher. If the maximum temperature during molding is 300°C or higher, the fluidity during molding can be increased, and a molded article with even lower birefringence can be obtained. That is, the aromatic polycarbonate resin of the present invention has excellent heat resistance and can be used for molding in a wide temperature range, particularly injection molding, so that the birefringence can be further reduced by molding at such high temperatures. From the viewpoint of reducing birefringence, the maximum temperature during molding is more preferably 310°C or higher, and even more preferably 340°C or higher. However, if the molding temperature is excessively high, the resin may undergo thermal decomposition during molding, so the maximum temperature during molding is preferably 400°C or lower.

The molded article of the present invention has excellent heat resistance and optical properties (high refractive index, low birefringence, etc.), and can be used as optical components such as optical films, optical lenses, and optical sheets.

In particular, the aromatic polycarbonate resin of the present invention is suitable for injection molding like conventional polycarbonate lenses, and is therefore useful for forming optical lenses. Examples of optical lenses include, but are not limited to, in-vehicle lenses, eyeglass lenses, pickup lenses, camera lenses, microarray lenses, projector lenses, and Fresnel lenses. In particular, the aromatic polycarbonate resin of the present invention has high heat resistance, and is therefore suitable for use in applications where use in high-temperature environments is expected, such as in-vehicle optical lenses.

The present invention will be described in more detail below with reference to synthesis examples and examples, but the present invention is not limited to the following examples.

The physical properties of the aromatic polycarbonate resins produced in the following examples and comparative examples were evaluated by the following methods.

(1) Melt Viscosity at 300° C., 1216 s ⁻¹ Measurement was carried out using a Capillograph 1B manufactured by Toyo Seiki Seisakusho Co., Ltd., in accordance with JIS K 7199, under conditions of 300° C., 1216 s ⁻¹ , and an orifice of 1 mmφ×10 mm.

(2) Specific viscosity [η _sp ]/viscosity average molecular weight (Mv)
The polycarbonate resin was dissolved in methylene chloride (concentration: 6.0 g/L), and the specific viscosity [η _sp ] was measured using an Ubbelohde viscosity gauge (manufactured by Moritomo Rika Kogyo Co., Ltd.). The viscosity (intrinsic viscosity) [η] (unit: dL/g) was measured, and the viscosity average molecular weight (Mv) was calculated from Schnell's viscosity formula (the following formula).
η=1.23×10 ⁻⁴ Mv ⁰ . ⁸³

(3) Glass transition temperature (Tg)
Using a differential scanning calorimeter DSC6220 manufactured by SII Nanotechnology, about 10 mg of the sample was heated at a heating rate of 20°C/min to measure the calorific value, and the extrapolated glass transition onset temperature was determined according to JIS K7121, which is the temperature at the intersection of a straight line extending the low-temperature side baseline to the high-temperature side and a tangent drawn at the point where the gradient of the curve of the stepwise change in the glass transition is maximum. The extrapolated glass transition temperature was designated as the glass transition temperature (Tg).

(4) 5% thermogravimetric reduction temperature (Td)
Using a TG/DTA7200 manufactured by SII Nanotechnology, approximately 10 mg of the sample was placed in a container, and measurements were taken from 30°C to 500°C at a heating rate of 10°C/min under a nitrogen atmosphere (nitrogen flow rate 50 ml/min). The temperature (Td) at which the weight decreased by % was determined.

(5) Refractive index (n _D ), Abbe number (ν _D )
About 4 g of the resin sample, which had been vacuum-dried at 100°C for 2 hours, was pressed in a heat press at a heat press temperature of 200-250°C, preheated for 1-3 minutes, and pressurized at a pressure of 20 MPa for 1 minute using a spacer with a width of 8 cm, length of 8 cm, and thickness of 0.5 mm, and then removed from the heat press at room temperature to produce a film with a thickness of 100-300 μm. A rectangular test piece with a length of 40 mm and a width of 8 mm was cut out from this film and used as a measurement sample. A multi-wavelength Abbe refractometer (DRM4/1550 manufactured by Atago Co., Ltd.) was used to measure the refractive indexes, n _C , n _D , and n _F of each wavelength using interference filters with wavelengths of 656 nm (C line), 589 nm (D line), and 486 nm (F line). The measurement was performed at 20°C using monobromonaphthalene as the interface liquid.
The Abbe number _νD was calculated by the following formula:
ν _D = (1-n _D )/(n _C -n _F )

(6) Test piece preparation method Using a small injection molding machine (Shinko Selvic C, Mobile), dumbbell-shaped resin plates with a total length of 75 mm, a parallel portion length of 30 mm, a parallel portion width of 5 mm, a thickness of 2 mm, and a gripping portion width of 10 mm were molded under the conditions of the cylinder temperature and the mold temperature shown in Tables 1A and 1B to obtain test pieces.

(7) Strength Evaluation The test specimens prepared by the above (6) Test Specimen Preparation Method were manually folded 90° at a position 37.5 mm from the end, i.e., at the center in the length direction. When five test specimens were folded 90°, the percentage of specimens that cracked was recorded in the form of a fraction.
In cases where a test specimen could not be molded using the above (6) Test specimen preparation method, this was indicated.

(8) Color Tone Evaluation The color tone of the test piece prepared in the above (6) Test Piece Preparation Method was visually observed and evaluated according to the following criteria.
◯: Transparent, with almost no coloring observed Δ: Transparent, but with obvious coloring observed ×: Opaque If a test specimen could not be molded by the above (6) Test Specimen Preparation Method, this was indicated.

(7) Birefringence The test piece prepared in the above (6) Test Piece Preparation Method was sandwiched between two polarizers in a crossed Nicol state at the angle at which the polarized color appears most strongly, and the test piece was placed on an observation table and irradiated with white light from behind. The polarized color appearing on the test piece was then visually observed, and the degree of birefringence was evaluated according to the following criteria.
⊚: No polarized color is seen, or polarized color is seen only in the 5 mm wide parallel portion, resulting in one color. ◯: Polarized color is seen only in the 5 mm wide parallel portion, resulting in two colors. △: Polarized color is seen only in the 5 mm wide parallel portion, resulting in three or more colors. ×: Polarized color is seen over the entire test piece. If a test piece could not be molded using the test piece preparation method (6) above, this was indicated.

[Synthesis Example 1: Synthesis of 1,1-bis(4-hydroxyphenyl)dodecane (hereinafter abbreviated as "BP12A")]
BP12A was synthesized by the method described in Example 1 of JP2019-085399A.

[Synthesis Example 2: Synthesis of 1,1-bis(4-hydroxyphenyl)decane (hereinafter abbreviated as "BP10A")]
BP10A was synthesized by the method described in <Synthesis Example 2> of WO 2017/099227.

[Synthesis Examples and Property Evaluation of Aromatic Polycarbonate Resins]
The abbreviations of the compounds used in the following Examples and Comparative Examples are as follows.
BisAP: 1,1-bis(4-hydroxyphenyl)-1-phenylethane (Tokyo Chemical Industry Co., Ltd.)
BisBP: bis(4-hydroxyphenyl)diphenylmethane (Tokyo Chemical Industry Co., Ltd.)
BCF: 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (manufactured by Osaka Gas Chemicals Co., Ltd.)
BNF: 6,6'-(9H-fluorene-9,9-diyl)bis(2-naphthol) (manufactured by BLD Pharmatech)
BP12A: 1,1-bis(4-hydroxyphenyl)dodecane BPA: 2,2-bis[4-hydroxyphenyl]propane (manufactured by Mitsubishi Chemical Corporation)
BP10A: 1,1-bis(4-hydroxyphenyl)decane BPEF: 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (Osaka Gas Chemicals Co., Ltd.)
DPC: Diphenyl carbonate (manufactured by Mitsubishi Chemical Corporation)
PTSB: catalyst deactivator, butyl paratoluenesulfonate (Tokyo Chemical Industry Co., Ltd.)
Adeka STAB 2112: Antioxidant, Adeka STAB 2112 (manufactured by ADEKA CORPORATION)
Irg1076: Antioxidant, Irganox 1076 (manufactured by BASF)

[Example 1]
A raw material mixture was prepared by adding 97.0 mol % of BisAP, 3.0 mol % of BP12A, 103.5 mol % of DPC, and a 0.4 mass % aqueous solution of cesium carbonate as a catalyst to a glass reactor equipped with a reactor stirrer, a reactor heating device, and a reactor pressure adjusting device, when the total amount of the raw material dihydroxy compounds was 100 mol %.

Next, the pressure inside the glass reactor was reduced to about 50 Pa (0.38 Torr), and then the pressure was returned to atmospheric pressure with nitrogen, and this operation was repeated three times to replace the inside of the reactor with nitrogen. After nitrogen replacement, the temperature outside the reactor was set to 220°C, and the temperature inside the reactor was gradually raised to dissolve the mixture. Then, the stirrer was rotated at 100 rpm. Then, while distilling off the phenol by-product of the oligomerization reaction of the dihydroxy compound and DPC that takes place inside the reactor, the pressure inside the reactor was reduced from 101.3 kPa (760 Torr) to 13.3 kPa (100 Torr) in absolute pressure over 40 minutes.

Then, the pressure inside the reactor was kept at 13.3 kPa, and the transesterification reaction was carried out for 80 minutes while further distilling off the phenol. After that, the temperature outside the reactor was raised to 250°C, and the pressure inside the reactor was reduced from 13.3 kPa (100 Torr) to 399 Pa (3 Torr) absolute pressure over 40 minutes, and the distilled phenol was removed from the system. Furthermore, the temperature outside the reactor was raised to 290°C, and the absolute pressure inside the reactor was reduced to 30 Pa (approximately 0.2 Torr), and the polycondensation reaction was carried out. The polycondensation reaction was terminated when the reactor agitator reached a predetermined stirring power.

Next, the pressure inside the reactor was restored to 101.3 kPa absolute pressure with nitrogen, and then the gauge pressure was increased to 0.2 MPa. The aromatic polycarbonate resin was extracted in the form of strands from the bottom of the reactor to obtain strands of aromatic polycarbonate resin. Then, a rotary cutter was used to obtain pellets of aromatic polycarbonate resin A.
The aromatic polycarbonate resin A was subjected to the above-mentioned procedures for each evaluation, and the results are shown in Table 1A.

[Examples 2 to 8, Comparative Examples 1 to 4]
An aromatic polycarbonate resin was obtained in the same manner as in Example 1, except that the raw materials and conditions of the melt polymerization were as shown in Tables 1A and 1B. The aromatic polycarbonate resin was evaluated according to the above procedures. The results are shown in Tables 1A and 1B.

[Examples 9 and 10]
For the resin C obtained in Example 3, a test piece was prepared by the above-mentioned method under the conditions of the cylinder temperature and the mold temperature shown in Table 2, and birefringence was evaluated. The results are shown in Table 2 together with the results of Example 3.

[Example 11]
Resin C obtained in Example 3 and additive components PTSB, ADK STAB 2112, and Irg1076 were blended and mixed in the ratios (parts by mass) shown in Table 3 below, and then fed to a Japan Steel Works (TEX30HSS) equipped with one vent, kneaded under conditions of a screw rotation speed of 160 rpm, a discharge rate of 15 kg/h, and a barrel temperature of 290°C, and the molten resin extruded in a strand shape was quenched in a water tank and pelletized using a pelletizer to obtain pellets of aromatic polycarbonate resin composition M. The birefringence of this polycarbonate resin composition M was evaluated by the above method. The results are shown in Table 3 together with the results of Example 3.

[Discussion of evaluation results]
It is seen that the aromatic polycarbonate resins A to H of Examples 1 to 8 are excellent in heat resistance, thermal stability and strength. Furthermore, they have excellent optical properties such as high _nD and small birefringence of the molded article.

As shown in Examples 9 and 10, the aromatic polycarbonate resin of the present invention can be injection molded at temperatures lower than 350°C, but a higher molding temperature is preferred from the viewpoint of birefringence.

As shown in Example 11, the aromatic polycarbonate resin of the present invention can be kneaded with additive components to form an aromatic polycarbonate resin composition, which can be injection molded and has low birefringence.

On the other hand, resin I of Comparative Example 1 has high Tg and Td, but does not contain the dihydroxy compound BP12A that forms the carbonate structural unit (B), and therefore has low strength.

In Comparative Example 2, Tg and Td are high, but _nD is low and the birefringence of the molded body is large. Since the optical properties are poor, it is disadvantageous as a material for optical components. In Comparative Example 2, unlike Example 1, the diol monomer BP12A forming the carbonate structural unit (B) is not used, and the composition ratio of BisAP forming the carbonate structural unit (A) is low, so the birefringence of the molded body is large. It is expected that the strength will decrease if the composition ratio of BisAP is increased in an attempt to increase _nD .

Resin K of Comparative Example 3 has the same Tg and Td as resin F of Example 6, but has a low _nD and a large birefringence of the molded body. It is disadvantageous as a material for optical components because of its inferior optical properties. Unlike Example 6, Comparative Example 3 uses BP10A instead of BP12A as the dihydroxy compound forming the carbonate structural unit (B), and has a low composition ratio of the dihydroxy compound BisBP forming the carbonate structural unit (A), so that the birefringence of the molded body is large. It is expected that the strength will decrease if the composition ratio of BisBP is increased in an attempt to increase _nD .

Comparative Example 4 has high _nD and small birefringence, but low Tg and Td, and is poor in heat resistance and thermal stability. Therefore, it cannot be used as a material for molded products that require high heat resistance. In addition, injection molding at a cylinder temperature of 350°C cannot be performed, and moldability is poor. This is because, unlike Resins A to H in Examples 1 to 8, the main skeleton is a carbonate bond derived from an aliphatic hydroxy compound, and the thermal stability is poor.

From the above, it can be seen that the aromatic polycarbonate resin and aromatic polycarbonate resin composition of the present invention have high heat resistance and thermal stability, as well as excellent optical properties such as a high refractive index and low birefringence, and further have excellent moldability, compared to the resins of the comparative examples.

The aromatic polycarbonate resin of the present invention has excellent optical properties such as a high refractive index and low birefringence while having high heat resistance and thermal stability, and further has excellent moldability.
Therefore, the aromatic polycarbonate resin of the present invention and the aromatic polycarbonate resin composition containing the same can be easily processed into optical members by a method such as injection molding, etc. These optical members have high heat resistance, a high refractive index, and low birefringence, and are therefore superior to optical members using conventional polycarbonate resins such as polycarbonate resins derived from bisphenol A.

Examples of such optical members include optical lenses, optical films, optical sheets, etc. Examples of optical lenses include in-vehicle lenses, eyeglass lenses, pickup lenses, camera lenses, microarray lenses, projector lenses, Fresnel lenses, etc. In particular, the aromatic polycarbonate resin of the present invention has high heat resistance and can be suitably used as a material for optical members that are expected to be used in high-temperature environments, such as in-vehicle lenses.

Claims (16)

An aromatic polycarbonate resin containing a carbonate structural unit (A) represented by the following formula (1) and a carbonate structural unit (B) represented by the following formula (5), and having a viscosity average molecular weight (Mv) of 5,000 to 17,200 .

(In formula (1), rings Z ¹ and Z ² each independently represent an aromatic hydrocarbon ring. R ¹ and R ² each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom. a and b each independently represent an integer of 0 or more. When a and b are 2 or more and there are multiple R ^1s and multiple R ^2s , the multiple R ^1s and R ^2s may be the same as or different from each other. At least two groups among the multiple R ^1s and/or R ^2s may be bonded to each other to form a ring. X is a group selected from the group consisting of divalent groups represented by the following formula (2) . The * mark in formula (2) indicates a bonding portion with rings Z ¹ and Z ² in formula (1).)

(In formula (2), R ³ is a hydrogen atom or an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms. R ⁴ is an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, or a halogen atom. c represents an integer of 0 to 5. When c is 2 or more and there are multiple R ^4s , the multiple R ^4s may be the same or different from each other. In addition, at least two groups among the multiple R ^4s may be bonded to each other to form a ring. )

(In formula (5), R ⁹ and R ¹⁰ each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted acyl group having 1 to 10 carbon atoms, an oxygen atom having a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, or a halogen atom. h and i each independently represent an integer of 0 to 4. When h and i are 2 or more and there are a plurality of R ^{9 s} and R ^{10 s} , the plurality of R ^{9 s} and R ^{10 s} may be the same as or different from each other. In addition, at least two groups among the plurality of R ^{9 s} and/or R ^{10 s} may be bonded to each other to form a ring. R ¹¹ and R ¹² each independently represent a hydrogen atom or an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms. However, the total number of carbon atoms of R ¹¹ and R ¹² is 11 or more and 40 or less.) The aromatic polycarbonate resin according to claim 1, in which the carbonate structural unit (A) is contained in an amount of 40 mol % or more and less than 100 mol % when the total number of moles of all carbonate structural units constituting the resin is 100 mol %. The aromatic polycarbonate resin according to claim 1 or 2, in which the carbonate structural unit (B) is contained in an amount of more than 0 mol% and not more than 60 mol% when the total number of moles of all carbonate structural units constituting the resin is taken as 100 mol%. The aromatic polycarbonate resin according to any one of claims 1 to 3, wherein in the formula (5), at least one of R ¹¹ and R ¹² has 11 or more carbon atoms. The aromatic polycarbonate resin according to any one of claims 1 to 4, wherein in the formula (5), R ¹¹ or R ¹² is a hydrogen atom. The aromatic polycarbonate resin according to claim 5, wherein the formula (5) is the following formula (6):

7. The aromatic polycarbonate resin according to claim 1, wherein in the formula (1), rings Z ¹ and Z ² are each independently selected from a benzene ring, a naphthalene ring, and an anthracene ring. The aromatic polycarbonate resin according to any one of claims 1 to 7, wherein in the formula (1), X is any one selected from the group consisting of divalent groups represented by the following formula (7) : (the * mark in the formula (7) indicates a bond to the rings ^Z1 and ^Z2 in the formula (1); and in the formula ( 7 ) , the benzene ring may have a substituent).

The aromatic polycarbonate resin according to any one of claims 1 to 8 , wherein the formula (1) is the following formula (10 ) :

The aromatic polycarbonate resin according to any one of claims 1 to 9 , having a Tg of 150 to 250°C. An aromatic polycarbonate resin composition comprising the aromatic polycarbonate resin according to any one of claims 1 to 10 and at least one additive selected from the group consisting of a heat stabilizer, an antioxidant, an ultraviolet absorber, a brightness enhancer, a dye, a pigment, a release agent, a flow modifier and an impact resistance improver. 11. An aromatic polycarbonate resin composition comprising the aromatic polycarbonate resin according to any one of claims 1 to 10 and another resin. A molded article obtained by using the aromatic polycarbonate resin according to any one of claims 1 to 10 , or the aromatic polycarbonate resin composition according to claim 11 or 12 . The molded article according to claim 13 , which is an optical component. The molded article according to claim 14 , wherein the optical member is at least one optical lens selected from the group consisting of an in-vehicle lens, a spectacle lens, a pickup lens, a camera lens, a microarray lens, a projector lens, and a Fresnel lens. A method for producing a molded article using the aromatic polycarbonate resin according to any one of claims 1 to 10 , or the aromatic polycarbonate resin composition according to claim 11 or 12 , characterized in that the maximum temperature during molding is 300°C or higher.