JP7685404B2 - Alicyclic polycarbonate resin having excellent heat resistance, resin composition, and method for producing same - Google Patents

Description

The present invention relates to an alicyclic polycarbonate resin with excellent heat resistance.

Polycarbonate resin is an engineering plastic with excellent heat resistance, and there is a demand for it to have excellent heat resistance and optical properties as well as being lightweight and low cost. In order to meet such demands, there has been active development of special polycarbonate resins based on aromatic skeletons.

On the other hand, aliphatic, particularly polycarbonate resins having alicyclic structures, are being developed as alternatives to aromatic polycarbonates. Alicyclic polycarbonates tend to have better light resistance and optical properties than polycarbonate resins having aromatic rings such as bisphenol A. For example, Patent Document 1 discloses a polycyclic alicyclic polycarbonate resin that is excellent in transparency, heat resistance, and color tone. Polycarbonates using not only petroleum-derived raw materials but also raw materials derived from biomass such as plants are also being developed. For example, Patent Document 2 discloses a polycarbonate resin using isosorbide, which can be derived from starch, as a raw material.

Among such alicyclic polycarbonate resins, poly(cyclohexene carbonate) having a cyclohexane carbonate structure is the simplest polycarbonate having a saturated six-membered carbon ring corresponding to a benzene ring. It is widely known that poly(cyclohexene carbonate) can be synthesized by the reaction of cyclohexene oxide with carbon dioxide, as shown in Patent Document 3, for example. It is also known that poly(cyclohexene carbonate) can be obtained by ring-opening polymerization of 1,2-cyclohexene carbonate, as described in Patent Document 4 and Non-Patent Document 1.

Patent No. 4774610 Patent No. 6507495 Patent No. 5403537 JP 2019-108547 A

Macromolecules 2014, 47, 4230-4235.

The inventors of the present invention conducted a detailed study of conventional polycarbonate resins, including those described in the above literature, and found that they had insufficient heat resistance.

For example, as described in Patent Document 4 and Non-Patent Document 1, the glass transition temperature of a polycarbonate resin having a cyclic cyclohexane structure in the main chain is higher than that of an aliphatic chain polycarbonate, but is lower than that of a general-purpose aromatic polycarbonate resin having a bisphenol A structure, and there remain issues in terms of heat resistance, such as morphological stability in high-temperature environments.

The present invention was made in consideration of the above problems, and aims to provide an alicyclic polycarbonate resin with excellent heat resistance.

As a result of intensive research into solving the above problems, the inventors discovered that polycarbonate resins having a specific cyclic structure in the main chain have excellent heat resistance, leading to the completion of the present invention.

That is, the present invention is as follows.
[1]
A structural unit represented by the following formula (1):
(In formula (1),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each independently a hydrogen atom, a hydroxyl group, a phosphate group, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, a silylalkoxy group having 1 to 30 carbon atoms, an ester group having 1 to 11 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an unsubstituted linear, branched or cyclic alkyl group having 1 to 10 carbon atoms; or R ¹ to R ¹² may form a cyclic structure together with the carbon element to which they are bonded, and in the cyclic structure, R ¹ to R ¹² are bonded to each other via an alkylene group or a carbonate group;
the alkylene group may be substituted with a hydroxyl group, a phosphate group, an alkoxy group having 1 to 10 carbon atoms, an ester group having 1 to 10 carbon atoms, or an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms;
X is an unsubstituted, mono- or di-substituted methylene group;
n is an integer from 0 to 2.
A polycarbonate resin having the formula:
[2]
[0023] The polycarbonate resin according to [1], in which R ³ , R ⁴ , R ⁵ , R ⁸ , R ⁹ and R ¹⁰ are hydrogen atoms, and n is 0 or 1.
[3]
The polycarbonate resin according to [1] or [2], in which R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are hydrogen atoms, and n is 0 or 1.
[4]
The polycarbonate resin according to any one of [1] to [3], having a polystyrene-equivalent weight average molecular weight (Mw) of 10,000 or more and 500,000 or less, as measured by size exclusion chromatography (SEC).
[5]
The polycarbonate resin according to any one of [1] to [4], having a glass transition temperature (Tg) measured by a differential scanning calorimeter of 125° C. or higher and 200° C. or lower.
[6]
A polycarbonate resin composition comprising the polycarbonate resin according to any one of [1] to [5] and an antioxidant.
[7]
An optical part comprising the polycarbonate resin according to any one of [1] to [5] or the polycarbonate resin composition according to [6].
[8]
Use of the polycarbonate resin according to any one of [1] to [5] or the polycarbonate resin composition according to [6] as a material for optical parts.
[9]
A method for producing the polycarbonate resin according to any one of [1] to [5], comprising reacting a compound represented by the following formula (2):
(In formula (2), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , X, and n are as defined in formula (1).)
The production method includes a polymerization step of ring-opening polymerizing a cyclic carbonate represented by the following formula (1):
[10]
A method for producing the polycarbonate resin according to any one of [1] to [5], comprising reacting a compound represented by the following formula (3):
(In formula (3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , X, and n are as defined in formula (1).)
and a polymerization step of reacting an epoxide represented by the following formula (I) with carbon dioxide to obtain the polycarbonate resin.

The present invention provides an alicyclic polycarbonate resin with excellent heat resistance.

The following provides a detailed description of the embodiment of the present invention (hereinafter, also referred to as the "present embodiment"). Note that the present invention is not limited to the present embodiment, and can be modified in various ways within the scope of the gist of the present invention.

<Polycarbonate resin>
The polycarbonate resin of the present embodiment has a structural unit represented by the following formula (1).

In formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² (hereinafter also referred to as "R ¹ to R ¹² ") are each independently a hydrogen atom, a hydroxyl group, a phosphate group, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, a silylalkoxy group having 1 to 30 carbon atoms, an ester group having 1 to 11 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, or R ¹ to R ¹² may form a cyclic structure together with the carbon element to which they are bonded, and in the cyclic structure, R ¹ to R ¹² are bonded to each other via an alkylene group or a carbonate group, and the alkylene group may be substituted with a hydroxyl group, a phosphate group, an alkoxy group having 1 to 10 carbon atoms, an ester group having 1 to 10 carbon atoms, or an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. X is an unsubstituted, mono- or di-substituted methylene group, and n is an integer of 0 to 2 (preferably 1 or 2, more preferably 1). When n is 0, the carbon atom to which R ⁴ is bonded and the carbon atom to which R ⁹ is bonded in formula (1) are not bonded.

From the viewpoint of more effectively and reliably achieving the effects of the present invention, R ¹ to R ¹² in formula (1) are preferably each independently one or more substituents selected from the group consisting of a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, an ester group having 1 to 11 carbon atoms, an acyl group having 1 to 11 carbon atoms, and an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. From the same viewpoint, R ¹ to R ¹² in formula (1) are more preferably each independently one or more substituents selected from the group consisting of a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, and an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. From the same viewpoint, in formula (1), R ¹ to R ¹² are more preferably each independently one or more substituents selected from the group consisting of a hydrogen atom, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, and an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms.

In this embodiment, in formula (1), R ¹ to R ¹² may be bonded to each other via an alkylene group or a carbonate group (-OC(=O)O- group) to form a cyclic structure, and the alkylene group may be substituted with a hydroxyl group, a phosphate group, an alkoxy group, or an ester group. From the viewpoint of more reliably and effectively achieving the effects of the present invention, when R ¹ to R ¹² are bonded to each other via an alkylene group to form a cyclic structure, the number of carbon atoms in the alkylene group is preferably 1 to 20, more preferably 1 to 15, and even more preferably 1 to 12. Furthermore, from the same viewpoint, the substituent of the alkylene group is preferably a hydroxyl group, an alkoxy group, or an ester group, and more preferably a hydroxyl group or an alkoxy group. From the same viewpoint, when R ¹ to R ¹² form a cyclic structure, the cyclic structure is preferably formed via an unsubstituted alkylene group. Examples of unsubstituted alkylene groups include methylene, ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,3-cyclopentylene, 1,6-hexylene, 1,3-cyclohexylene, and 1,4-cyclohexylene groups.

When R ¹ to R ¹² form a cyclic structure, it is preferable that any two of R ¹ to R ¹² are combined to form a cyclic structure.

The phosphate group in the above formula (1) of this embodiment may be unsubstituted or substituted. That is, it may be a monosubstituted phosphate group or a disubstituted phosphate group. From the viewpoint of more effectively and reliably achieving the effects of the present invention, when the phosphate group is substituted, it is preferable that the substituent is an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. From the same viewpoint, it is preferable that the phosphate group in this embodiment is unsubstituted.

The aryl group having 6 to 20 carbon atoms in the above formula (1) of this embodiment is not particularly limited, but examples thereof include unsubstituted or alkyl-containing aryl groups such as phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, tetramethylphenyl, pentamethylphenyl, ethylphenyl, propylphenyl, and diisopropylphenyl groups, aryl groups having alkoxy groups such as 4-methoxyphenyl and 3,5-dimethoxyphenyl groups, and biphenyl, naphthyl, and anthracenyl groups.

The aralkyl group having 6 to 20 carbon atoms in the above formula (1) of this embodiment is not particularly limited, but examples thereof include unsubstituted or alkyl group-containing aralkyl groups such as benzyl group, 4-methylbenzyl group, and phenethyl group, alkoxy group-containing aralkyl groups such as 4-methoxybenzyl group and 3,5-dimethoxybenzyl group, and diphenylmethyl group, naphthylmethyl group, and anthracenylmethyl group.

In the above formula (1) of this embodiment, the alkoxy group having 1 to 10 carbon atoms is not particularly limited, but examples thereof include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a 2-butoxy group, a tert-butoxy group, a pentyloxy group, a 2-pentyloxy group, a 3-pentyloxy group, a neopentyloxy group, a hexyloxy group, a 2-hexyloxy group, a 3-hexyloxy group, a 2-methylpentyloxy group, a 3-methylpentyloxy group, and a 2-methylpentyloxy group. oxy group, 4-methylpentyloxy group, 2-ethylbrooxy group, heptyloxy group, 2-heptyloxy group, 3-heptyloxy group, 4-heptyloxy group, 2-methylhexyloxy group, 3-methylhexyloxy group, 4-methylhexyloxy group, 5-methylhexyloxy group, 2-ethylpentyloxy group, 3-ethylpentyloxy group, octyloxy group, 2-octyloxy group, 3-octyloxy group, 4-octyloxy group, 2-methyl ethylheptyloxy group, 3-methylheptyloxy group, 4-methylheptyloxy group, 2-ethylhexyloxy group, 3-ethylhexyloxy group, nonanyloxy group, 2-nonanyloxy group, 3-nonanyloxy group, 4-nonanyloxy group, 5-nonanyloxy group, 2-methyloctyloxy group, 3-methyloctyloxy group, 4-methyloctyloxy group, 5-methyloctyloxy group, 2-ethylheptyloxy group, 3-ethylheptyloxy group oxy group, 4-ethylheptyloxy group, decyloxy group, 2-decyloxy group, 3-decyloxy group, 4-decyloxy group, 5-decyloxy group, 2-methylnonanyloxy group, 3-methylnonanyloxy group, 4-methylnonanyloxy group, 5-methylnonanyloxy group, 6-methylnonanyloxy group, 2-ethyloctyloxy group, 3-ethyloctyloxy group, 4-ethyloctyloxy group, and 5-ethyloctyloxy group.

The silyl group having 1 to 30 carbon atoms in the above formula (1) of this embodiment is not particularly limited, but examples thereof include a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, a cyclohexyldimethylsilyl group, a bis(trimethylsiloxy)methylsilyl group, a triphenylsilyl group, a tert-butyldimethylsilyl group, a di-tert-butylisobutylsilyl group, and a tert-butyldiphenylsilyl group.

In the above formula (1) of this embodiment, the silylalkoxy group having 1 to 30 carbon atoms is not particularly limited, but examples thereof include a trimethylsilylmethoxy group, a trimethylsilylethoxy group, a trimethylsilylphenoxy group, a trimethylsilylbenzyloxy group, a triethylsilylmethoxy group, a triethylsilylethoxy group, a triethylsilylphenoxy group, a triethylsilylbenzyloxy group, a triisopropylsilylmethoxy group, a triisopropylsilylethoxy group, a triisopropylsilylphenoxy group, a triisopropylsilylbenzyloxy group, a triphenylsilylmethoxy group, a triphenylsilylethoxy group, a triphenylsilylphenoxy group, a triphenylsilyl These include a tert-butyldimethylsilyl methoxy group, a tert-butyldimethylsilyl ethoxy group, a tert-butyldimethylsilyl phenoxy group, a tert-butyldimethylsilyl benzyloxy group, a di-tert-butylisobutylsilyl methoxy group, a di-tert-butylisobutylsilyl ethoxy group, a di-tert-butylisobutylsilyl phenoxy group, a di-tert-butylisobutylsilyl benzyloxy group, a tert-butyldiphenylsilyl methoxy group, a tert-butyldiphenylsilyl ethoxy group, a tert-butyldiphenylsilyl phenoxy group, and a tert-butyldiphenylsilyl benzyloxy group.

In the above formula (1) of this embodiment, the ester group having 1 to 11 carbon atoms is not particularly limited, but examples thereof include a methyl ester group, an ethyl ester group, a propyl ester group, a butyl ester group, a pentyl ester group, a cyclopentyl ester group, a hexyl ester group, a cyclohexyl ester group, a heptyl ester group, an octyl ester group, a nonanyl ester group, a decyl ester group, a phenyl ester group, a benzyl ester group, a vinyl ester group, and an allyl ester group.

In the above formula (1) of this embodiment, the acyl group having 1 to 11 carbon atoms is not particularly limited, but examples thereof include a formyl group, an acetyl group, a propionyl group, a butyryl group, a valeryl group, and a benzoyl group.

In the above formula (1) of this embodiment, examples of the unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a cyclopentyl group, an n-hexyl group, a cyclohexyl group, an n-heptyl group, a 1-norbornyl group, a 2-norbornyl group, an n-octyl group, a 1-bicyclo[2.2.2]octyl group, a 2-bicyclo[2.2.2]octyl group, an n-nonanyl group, an n-decyl group, a 1-adamantyl group, and a 2-adamantyl group.

In the above formula (1) of this embodiment, the unsubstituted, mono-substituted or di-substituted methylene group represented by X is not particularly limited, but examples thereof include a methylene group, a methylmethylene group, and a dimethylmethylene group.

The polycarbonate resin of this embodiment has the above-mentioned configuration, and therefore exhibits a high glass transition temperature and excellent heat resistance. This is thought to be due to the following factors, but is not limited to these.

Conventional alicyclic polycarbonate resins, such as poly(cyclohexene carbonate), have a cycloalkane skeleton with moderate flexibility. In contrast, the polycarbonate resin of the present embodiment has a structure in which the cycloalkane skeleton is condensed, and therefore the flexibility of the ring skeleton is reduced and it becomes more rigid, which is presumably why excellent heat resistance is exhibited.

In the above formula (1), preferably, ^R3 , ^R4 , ^R5 , ^R8 , ^R9 , and ^R10 are hydrogen atoms and n is 0 or 1, and more preferably, ^R3 , ^R4 , ^R5 , ^R8 , ^R9 , and ^R10 are hydrogen atoms and n is 1.

In the above formula (1), preferably, ^R1 , ^R2 , ^R3 , ^R4 , ^R5 , ^R8 , ^R9 , ^R10 , ^R11 , and ^R12 are hydrogen atoms and n is 0 or 1, and more preferably, ^R1 , ^R2 , ^R3 , ^R4 , ^R5 , ^R8 , ^R9 , ^R10 , ^R11 , and ^R12 are hydrogen atoms and n is 1.

The polycarbonate resin of the present embodiment may have other structural units in addition to the structural unit represented by formula (1).
Examples of the other structural units include ring-opened cyclic carbonate units. More specifically, examples of the other structural units include structural units represented by the following formula (X1).

In formula (X1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently represent a hydrogen atom, a hydroxyl group, a phosphate group, a vinyl group, an allyl group, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, a silylalkoxy group having 1 to 30 carbon atoms, an ester group having 1 to 11 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, or R ¹ to R ⁸ may form a cyclic structure together with the carbon element to which they are bonded, and in the cyclic structure, R ¹ to R ⁸ are bonded to each other via an alkylene group or a carbonate group. In formula (X1), examples of the phosphate group, the aryl group having 6 to 20 carbon atoms, the aralkyl group having 6 to 20 carbon atoms, the alkoxy group having 1 to 10 carbon atoms, the silyl group having 1 to 30 carbon atoms, the silylalkoxy group having 1 to 30 carbon atoms, the ester group having 1 to 11 carbon atoms, the acyl group having 1 to 11 carbon atoms, and the unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms are the same as those in formula (1).

From the viewpoint of more effectively and reliably achieving the effects of the present invention, in formula (X1), R ¹ to R ⁸ are preferably each independently one or more substituents selected from the group consisting of a hydrogen atom, a hydroxyl group, a vinyl group, an allyl group, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, a silylalkoxy group having 1 to 30 carbon atoms, an ester group having 1 to 11 carbon atoms, an acyl group having 1 to 11 carbon atoms, and an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, or a cyclic structure bonded to each other via an alkylene group or a carbonate group. From the same viewpoint, in formula (X1), R ¹ to R ⁸ are more preferably each independently one or more substituents selected from the group consisting of a hydrogen atom, a hydroxyl group, a vinyl group, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, and a silylalkoxy group having 1 to 30 carbon atoms, or a cyclic structure bonded to each other via an alkylene group or a carbonate group. From the same viewpoint, in formula (X1), R ¹ to R ⁸ are more preferably each independently a cyclic structure bonded to each other via one or more substituents selected from the group consisting of a hydrogen atom, a hydroxyl group, a vinyl group, an alkoxy group having 1 to 10 carbon atoms, and a silylalkoxy group having 1 to 30 carbon atoms, or a carbonate group.

The proportion of the structural unit represented by formula (1) in the polycarbonate resin of this embodiment is not particularly limited. For example, the lower limit of the proportion of the structural unit may be 10 mol%, 20 mol%, 30 mol%, 40 mol%, 50 mol%, 60 mol%, 70 mol%, 80 mol%, or 90 mol%. For example, the upper limit of the proportion of the structural unit may be 100 mol%, 90 mol%, 80 mol%, 70 mol%, 60 mol%, 50 mol%, 40 mol%, 30 mol%, or 20 mol%. The upper and lower limits can be arbitrarily combined to obtain various numerical ranges.

The proportion of the structural unit represented by formula (X1) in the polycarbonate resin of this embodiment is not particularly limited. For example, the lower limit of the proportion of the structural unit may be 0 mol%, 10 mol%, 20 mol%, 30 mol%, 40 mol%, 50 mol%, 60 mol%, 70 mol%, or 80 mol%. For example, the upper limit of the proportion of the structural unit may be 90 mol%, 80 mol%, 70 mol%, 60 mol%, 50 mol%, 40 mol%, 30 mol%, 20 mol%, or 10 mol%. The upper and lower limits can be arbitrarily combined to provide various numerical ranges.

(Terminal structure)
The polycarbonate resin of the present embodiment preferably has the terminal structures represented by R ¹³ and R ¹⁴ in the following formula (1-1).

In formula (1-1), R ¹³ and R ¹⁴ are each independently a hydrogen atom, a hydroxyl group, a phosphate group, an amino group, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, a silylalkoxy group having 1 to 30 carbon atoms, an ester group having 1 to 11 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. In formula (1-1), R ¹ to R ¹² , X, and n are the same as those in formula (1).

In the polycarbonate resin of the present embodiment, R ¹³ and R ¹⁴ in the above formula (1-1) may be bonded to each other to form a cyclic structure, that is, the polycarbonate resin may not have the terminal structure represented by R ¹³ and R ¹⁴ .

In this embodiment, preferred R ¹ to R ¹² in formula (1-1) are the same as those in formula (1). In addition, examples of the phosphate group, the aryl group having 6 to 20 carbon atoms, the aralkyl group having 6 to 20 carbon atoms, the alkoxy group having 1 to 10 carbon atoms, the silyl group having 1 to 30 carbon atoms, the silylalkoxy group having 1 to 30 carbon atoms, the ester group having 1 to 11 carbon atoms, the acyl group having 1 to 11 carbon atoms, the unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, and X in formula (1-1) are also the same as those in formula (1). From the viewpoint of more effectively and reliably exerting the effects of the present invention, in formula (1-1), R ¹³ and R ¹⁴ are preferably each independently one or more substituents selected from the group consisting of a hydrogen atom, a hydroxyl group, an amino group, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, a silylalkoxy group having 1 to 30 carbon atoms, an ester group having 1 to 11 carbon atoms, an acyl group having 1 to 11 carbon atoms, and an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. From the same viewpoint, in formula (1-1), R ¹³ and R ¹⁴ are more preferably each independently one or more substituents selected from the group consisting of a hydrogen atom, a hydroxyl group, an amino group, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, a silylalkoxy group having 1 to 30 carbon atoms, an acyl group having 1 to 11 carbon atoms, and an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. From the same viewpoint, in formula (1-1), R ¹³ and R ¹⁴ are more preferably each independently one or more substituents selected from the group consisting of a hydrogen atom, a hydroxyl group, an amino group, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a silyl group having 1 to 30 carbon atoms, a silylalkoxy group having 1 to 30 carbon atoms, and an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms.

In the polycarbonate resin of this embodiment, the weight average molecular weight (Mw) in terms of polystyrene measured by size exclusion chromatography (SEC) is preferably 10,000 or more and 500,000 or less. The polycarbonate resin of this embodiment is easy to mold when the Mw is within the above range. In addition, such a polycarbonate resin has excellent heat resistance. From the same viewpoint, Mw is more preferably 10,000 or more and 450,000 or less, and even more preferably 10,000 or more and 400,0000 or less. The upper limit of Mw may be 300,000. The weight average molecular weight of the polycarbonate resin measured by size exclusion chromatography can be specifically measured by the method described in the Examples.

In the polycarbonate resin of this embodiment, in order to control the weight average molecular weight (Mw) within the above range, the ratio of the polymerizable monomer and the polymerization initiator may be appropriately adjusted, and the polycarbonate resin may be produced by the production method described below. By controlling the amount of polymerization initiator added to the polymerizable monomer within a specific range, the polymerization reaction tends to proceed with a good conversion rate and the Mw tends to be large.

In the polycarbonate resin of this embodiment, the glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) is preferably 125°C or higher and 200°C or lower. If the Tg is 125°C or higher, the shape tends to be better maintained even in a relatively high temperature usage environment, and the heat resistance is excellent. Also, if the Tg is 200°C or lower, the moldability tends to be better. From the same viewpoint, the glass transition temperature of the polycarbonate resin of this embodiment is more preferably 125°C or higher and 195°C or lower, and even more preferably 125°C or higher and 190°C or lower. Specifically, the glass transition temperature of the polycarbonate resin can be measured by the method described in the examples.

In order to control the glass transition temperature Tg of the polycarbonate resin of this embodiment within the above preferred range, R ¹ to R ¹² in formula (1) may be appropriately selected, and the cyclic carbonate may be produced by the production method described below.

The polycarbonate resin of the present embodiment has a structural unit represented by formula (1) and therefore exhibits low birefringence.
In the polycarbonate resin of this embodiment, the absolute value of the photoelastic coefficient is preferably 10×10 ⁻¹² Pa ⁻¹ or less. Since the absolute value of the photoelastic coefficient is within the above range, the phase difference change when strain is applied to the polycarbonate resin can be suppressed, so that the polycarbonate resin tends to exhibit even lower birefringence. From the same viewpoint, the absolute value of the photoelastic coefficient of the polycarbonate resin of this embodiment is more preferably 8×10 ⁻¹² Pa ⁻¹ or less, and even more preferably 5×10 ⁻¹² Pa ⁻¹ or less. In addition, the lower limit of the absolute value of the photoelastic coefficient is not particularly limited, and may be 0 Pa ⁻¹ . The photoelastic coefficient of the polycarbonate resin can be specifically measured by the method described in the Examples. The test piece used in measuring the photoelastic coefficient of the polycarbonate resin of this embodiment is molded into a film at 150° C. or more and 300° C. or less. In addition, the film thickness of the film to be prepared is preferably 10 μm or more and 1000 μm or less.

In the polycarbonate resin of this embodiment, in order to control the absolute value of the photoelastic coefficient within the above-mentioned preferred range, R ¹ to R ¹² in formula (1) may be appropriately selected, and the polycarbonate resin may be produced by the production method described below. In particular, when the above-mentioned preferred R ¹ to R ¹² are selected, the absolute value of the photoelastic coefficient tends to be small.

In the polycarbonate resin of this embodiment, the absolute value of the in-plane retardation of the 100% uniaxially stretched film is preferably 100 nm or less in terms of a thickness of 100 μm. By having the absolute value of the in-plane retardation within the above range, there is a tendency that the manifestation of birefringence of the polycarbonate resin caused by the orientation of the molecules contained in the polymer chain can be further suppressed. From the same viewpoint, in the polycarbonate resin of this embodiment, the absolute value of the in-plane retardation of the 100% uniaxially stretched film is more preferably 80 nm or less in terms of a thickness of 100 μm, and even more preferably 60 nm or less in terms of a thickness of 100 μm. In addition, the lower limit of the absolute value of the in-plane retardation is not particularly limited, and may be 0 nm in terms of a thickness of 100 μm. Specifically, the in-plane retardation of the polycarbonate resin can be measured by the method described in the examples. A 100% uniaxially stretched film of polycarbonate resin refers to a film obtained by forming polycarbonate resin into a film shape using a method such as casting or vacuum hot pressing, and then stretching the polycarbonate resin 100% in a uniaxial direction under a temperature condition equal to or higher than the glass transition temperature. The film before stretching is formed at 150°C or higher and 300°C or lower, and the thickness of the film to be produced is preferably 10 μm or higher and 1000 μm or lower.

In the polycarbonate resin of this embodiment, in order to control the absolute value of the in-plane retardation within the above-mentioned preferred range, R ¹ to R ¹² in formula (1) may be appropriately selected, and the polycarbonate resin may be produced by the production method described below. In particular, when the above-mentioned preferred R ¹ to R ¹² are selected, the absolute value of the in-plane retardation tends to be small.

<Polycarbonate resin composition>
The polycarbonate resin composition of the present embodiment contains the above-mentioned polycarbonate resin and an antioxidant.

The polycarbonate resin composition of this embodiment contains an antioxidant, which can further prevent deterioration due to heat and shear during molding processing, and therefore the heat resistance of the polycarbonate resin composition can be further improved. In addition, the polycarbonate resin composition of this embodiment contains an antioxidant, which can further prevent the polycarbonate resin from being oxidized during use, and therefore the light resistance of the polycarbonate resin composition can be further improved.

The antioxidant in the polycarbonate resin composition of this embodiment is not particularly limited, but examples include hindered phenol-based antioxidants and phosphorus-based antioxidants.

Examples of hindered phenol-based antioxidants include, but are not limited to, Irganox 1010 (Irganox 1010: pentaerythritol tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]), Irganox 1076 (Irganox 1076: octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate), and Irganox 1330 (Irganox 1330: 3,3',3'',5,5',5''-hexa-t-butyl-a,a',a''-(mesitylene-2,4,6-triyl)tri-p-cresol), Irganox 3114 (Irganox 3114: 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione), Irganox 3125 (Irganox 3125), Adekastab AO-60 (pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]), Adekastab AO-80 (3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane), Cyanox 1790, Sumilizer GA-80, Sumilizer GS Examples of such acrylates include GS: 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, and Sumilizer GM (2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate). These may be used alone or in combination of two or more.

Phosphorus-based antioxidants are not particularly limited, but examples thereof include Irgafos 168 (Irgafos 168: tris(2,4-di-t-butylphenyl)phosphite), Irgafos 12 (Irgafos 12: tris[2-[[2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]ethyl]amine), ADKSTAB HP-10 (ADKSTAB HP-10: 2,2'-methylenebis(4,6-di-tert-butylphenyl)octylphosphite), ADKSTAB PEP36 (ADKSTAB PEP36: bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite), and ADKSTAB PEP36A (ADKSTAB PEP36A: bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite), Sumilizer GP (6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenz[d,f][1,3,2]dioxaphosphepine), and GSY P101 (tetrakis(2,4-di-t-butyl-5-methylphenyl)4,4'-biphenylene diphosphonite). These may be used alone or in combination of two or more.

The polycarbonate resin in the polycarbonate resin composition of this embodiment is the same as the polycarbonate resin described above, and the preferred aspects are also the same.

From the viewpoint of more effectively and reliably achieving the effects of the present invention, the content of the polycarbonate resin in the polycarbonate resin composition of this embodiment is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and less than 100% by mass, and even more preferably 65% by mass or more and less than 100% by mass, based on the entire resin composition.

From the viewpoint of further preventing deterioration due to heat and shear during molding, the content of the antioxidant in the polycarbonate resin composition of this embodiment is preferably 0.001% by mass or more and 1% by mass or less, more preferably 0.003% by mass or more and 1% by mass or less, and even more preferably 0.005% by mass or more and 1% by mass or less, based on the entire resin composition.

<Optical components>
The optical component of the present embodiment contains the above-mentioned polycarbonate resin or the above-mentioned polycarbonate resin composition.

The polycarbonate resin or the polycarbonate resin composition contained in the optical component of this embodiment has a small photoelastic coefficient and an in-plane retardation due to molecular orientation, so the optical component of this embodiment is less likely to exhibit stress birefringence and orientation birefringence. Therefore, the optical component of this embodiment tends to be able to suppress birefringence during use. Furthermore, the polycarbonate resin or the polycarbonate resin composition contained in the optical component of this embodiment has excellent heat resistance as described above, so the optical component of this embodiment is less likely to deteriorate over time and can be used for a longer period of time than conventional optical components.

The optical components in this embodiment are not particularly limited, but examples include optical lenses such as cameras, telescopes, microscopes, projectors, and vehicle-mounted lenses, as well as optical films such as diffusion plates, light guide plates, polarizing plates, and retardation films. The optical components in this embodiment are obtained by appropriately processing the above polycarbonate resin or the above polycarbonate resin composition, such as molding, so as to have a shape suitable for the application.

<Production method 1 of polycarbonate resin>
The method for producing a polycarbonate resin according to the present embodiment includes a step of ring-opening polymerizing a cyclic carbonate (A1) represented by the following formula (2).

In formula (2), ^R1 , ^R2 , ^R3 , ^R4 , ^R5 , ^R6 , ^R7 , ^R8 , ^R9 , ^R10 , ^R11 , ^R12 , X, and n are as explained in relation to formula (1).

In the method for producing a polycarbonate resin of this embodiment, the cyclic carbonate (A1) used in the ring-opening polymerization may be one type of cyclic carbonate alone, or any two or more types of cyclic carbonates having different R ¹ to R ¹² may be used in combination.

In the method for producing a polycarbonate resin of this embodiment, the cyclic carbonate (A1) includes cyclic carbonates (B1) to (B8) represented by the following formulas (2-1) to (2-8).

In formulas (2-1) to (2-8), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , X, and n are as explained in relation to formula (1). The stereochemistry around the asymmetric carbon marked with * may be either R or S.

From the viewpoint of more effectively and reliably achieving the effects of the present invention, it is preferable to increase the proportion of cyclic carbonates represented by (B1) to (B2) and (B5) to (B6) in which the carbonate groups form a 1,2-trans structure in the cyclic carbonate (A1) used in the ring-opening polymerization.

In the method for producing a polycarbonate resin of this embodiment, in addition to the cyclic carbonate (A1), other cyclic carbonates may be used.
An example of the other cyclic carbonate is a cyclic carbonate (A2) represented by the formula (X2).

In formula (X2), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ are as explained in relation to formula (X1). In the method for producing a polycarbonate resin of this embodiment, as the cyclic carbonate (A2) used in the ring-opening polymerization, one type of cyclic carbonate may be used alone, or any two or more types of cyclic carbonates having different R ¹ to R ⁸ may be used in combination.

(Polymerization initiator)
The polymerization initiator for ring-opening polymerization of the cyclic carbonates (A1) and (A2) is not particularly limited, but examples thereof include acid catalysts, base catalysts, and enzyme catalysts. The base catalyst is not particularly limited, but examples thereof include alkyl metals, metal alkoxides, metal amides, metal organic acid salts, cyclic amines such as cyclic monoamines and cyclic diamines (particularly, cyclic diamine compounds having an amidine skeleton), triamine compounds having a guanidine skeleton, and heterocyclic compounds containing a nitrogen atom. The alkyl metal is not particularly limited, but examples thereof include organic lithium such as methyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, and phenyl lithium, methyl magnesium halide, ethyl magnesium halide, propyl magnesium halide, phenyl magnesium halide, trimethyl aluminum, and triethyl aluminum. Among them, methyl lithium, n-butyl lithium, or sec-butyl lithium is preferably used. The metal ion in the metal alkoxide is not particularly limited, but examples thereof include alkali metals and alkaline earth metal ions, and preferably alkali metals. Examples of the alkoxide ion include, but are not limited to, methoxide, ethoxide, propoxide, butoxide, phenoxide, and benzyl oxide. Phenoxide and benzyl oxide may have a substituent on the aromatic ring. Examples of the metal amide include, but are not limited to, lithium amide, sodium amide, potassium amide, lithium bis(trimethylsilyl)amide, sodium bis(trimethylsilyl)amide, and potassium bis(trimethylsilyl)amide. Examples of the organic acid ion in the metal organic acid salt include, but are not limited to, a carboxylate ion having 1 to 10 carbon atoms. Examples of the metal in the metal organic acid salt include, but are not limited to, lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, and tin. Examples of the base catalyst include, but are not limited to, an organic base. The organic base is not particularly limited, but examples thereof include 1,4-diazabicyclo-[2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), diphenylguanidine (DPG), N,N-dimethyl-4-aminopyridine (DMAP), imidazole, pyrimidine, purine, and phosphazene base. From the viewpoint of more effectively and reliably exerting the effects of the present invention, the polymerization initiator of the present embodiment is preferably an alkyl metal, a metal alkoxide, or a metal amide, and more preferably a metal alkoxide or a metal amide.

In the polymerization step of the method for producing a polycarbonate resin according to the present embodiment, the amount of the polymerization initiator used may be adjusted appropriately according to the target molecular weight of the polycarbonate resin. From the viewpoint of controlling the weight average molecular weight (Mw) of the polycarbonate resin to a range of 10,000 to 500,000, the amount of the polymerization initiator used is preferably 0.0001 mol% to 4 mol%, more preferably 0.0001 mol% to 2 mol%, and even more preferably 0.0001 mol% to 1 mol% in terms of the amount of substance relative to the cyclic carbonate (A1) which is a ring-opening polymerizable monomer. In addition, the above polymerization initiators may be used alone or in combination of two or more kinds.

(Polymerization terminator)
From the viewpoint of controlling the average molecular weight of the resulting polycarbonate resin, a polymerization terminator may be used in addition to the polymerization initiator. The polymerization terminator is not particularly limited, but examples thereof include inorganic acids and organic acids such as hydrochloric acid, sulfuric acid, nitric acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, phosphoric acid, metaphosphoric acid, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, citric acid, ascorbic acid, gluconic acid, oxalic acid, tartaric acid, Meldrum's acid, and benzoic acid.

(Additives)
From the viewpoint of controlling the molecular weight of the resulting polymer and from the viewpoint of expressing various properties by controlling the terminal structure, additives may be used in addition to the above polymerization initiator. The additives are not particularly limited, but examples thereof include monoalcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, nonanol, decanol, dodecanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, 5-norbornene-2-methanol, 1-adamantanol, 2-adamantanol, trimethylsilylmethanol, phenol, benzyl alcohol, and p-methylbenzyl alcohol, dialcohols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexanediol, nonanediol, tetramethylene glycol, and polyethylene glycol, polyhydric alcohols such as glycerol, sorbitol, xylitol, ribitol, erythritol, and triethanolamine, and methyl lactate and ethyl lactate. The above additives may be used alone or in combination of two or more.

(Reaction temperature)
In the method for producing a polycarbonate resin of this embodiment, the reaction temperature in the polymerization step is not particularly limited as long as it is within a range in which the polycarbonate resin of this embodiment can be produced, but is preferably from 0° C. to 150° C., more preferably from 0° C. to 130° C., and even more preferably from 0° C. to 120° C. If the reaction temperature in the polymerization step is within the above range, it becomes easier to control the weight average molecular weight of the obtained polycarbonate resin to a range of from 10,000 to 500,000.

(solvent)
In the method for producing a polycarbonate resin according to the present embodiment, a solvent may or may not be used. The solvent is not particularly limited, but examples thereof include ether-based solvents such as diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,4-dioxane, cyclopentyl methyl ether, tert-butyl methyl ether, and propylene glycol monomethyl ether acetate, halogen-based solvents such as methylene chloride, chloroform, dichloromethane, dichloroethane, and trichloroethane, saturated hydrocarbon-based solvents such as hexane, heptane, octane, nonane, cyclohexane, and methylcyclohexane, aromatic hydrocarbon-based solvents such as toluene, xylene, o-xylene, m-xylene, p-xylene, and cresol, and ketone-based solvents such as acetone, 2-butanone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone, and methyl isobutyl ketone.

<Production method 2 of polycarbonate resin>
The polycarbonate resin of the present embodiment can also be produced by reacting an epoxide (C1) represented by the following formula (3) with carbon dioxide.

In formula (3), ^R1 , ^R2 , ^R3 , ^R4 , ^R5 , ^R6 , ^R7 , ^R8 , ^R9 , ^R10 , ^R11 , ^R12 , X, and n are as explained in relation to formula (1).

In the method for producing a polycarbonate resin of this embodiment, the epoxide compound (C1) used may be one type of epoxide compound alone, or any two or more types of epoxide compounds having different R ¹ to R ¹² may be used in combination.

In the method for producing a polycarbonate resin according to the present embodiment, in addition to the epoxide (C1), other epoxides may be used. Examples of other epoxides include the epoxide (C2) represented by the formula (X3).

In formula (X3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ are as explained in relation to formula (X1). In the method for producing a polycarbonate resin of this embodiment, the epoxide (C2) used may be one type of epoxide alone, or any two or more types of epoxides having different R ¹ to R ⁸ may be used in combination.

In the method for producing a polycarbonate resin of this embodiment, the epoxide compound (C1) includes epoxides (D1) to (D4) represented by the following formulas (3-1) to (3-4).

In formulas (3-1) to (3-4), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , X, and n are as explained in relation to formula (1). The stereochemistry around the asymmetric carbon marked with * may be either R or S.

The present invention will be explained in more detail using examples and comparative examples, but the present invention is not limited to these examples in any way.

In this specification, the physical properties of polycarbonate resin were measured as follows.

( ^1H -NMR measurement)
^{The 1H} -NMR spectrum of the polycarbonate resin was obtained by performing NMR measurement as follows using a JEOL NMR device (product name: ECZ400S) and a TFH probe. The reference peak of the deuterated solvent was set to 7.26 ppm when chloroform-d was used, and the measurement was performed with 32 integrations.

(Measurement of molecular weight)
A solution in which tetrahydrofuran was added at a ratio of 2.0 g to 0.02 g of polycarbonate resin was used as a measurement sample, and the weight average molecular weight of the polycarbonate resin was measured using a high-speed GPC device (manufactured by Tosoh Corporation, product name "HLC-8420GPC"). As the column, TSK guard columns SuperH-H, TSKgel SuperHM-H, TSKgel SuperHM-H, TSKgel SuperH2000, and TSKgel SuperH1000 (all product names manufactured by Tosoh Corporation) manufactured by Tosoh Corporation were connected in series and used. The column temperature was 40°C, and tetrahydrofuran was used as the mobile phase, and analysis was performed at a rate of 0.60 mL/min. An RI detector was used as the detector. A calibration curve was prepared using polystyrene standard samples (molecular weights: 2520000, 1240000, 552000, 277000, 130000, 66000, 34800, 19700, 8680, 3470, 1306, 370) manufactured by Polymer Standards Service as standard samples. Based on the calibration curve thus prepared, the number average molecular weight and weight average molecular weight of the polycarbonate resin were determined.

(Measurement of Glass Transition Temperature)
About 5 mg of the polycarbonate resin obtained in the examples and comparative examples described below was used as a measurement sample, and the glass transition temperature was measured using a differential scanning calorimeter (product name "DSC8500") manufactured by PerkinElmer Japan Co., Ltd. under the condition of a nitrogen gas flow rate of 20 mL/min. More specifically, for example, the sample of Example 1 was held at 40°C for 3 minutes, and then the sample was heated for the first time from 40°C to 210°C at 20°C/min to completely melt the sample. Then, the temperature was lowered from 210°C to 40°C at 50°C/min, and the sample was held at 40°C for 5 minutes. Next, the intersection (midpoint glass transition temperature) of the step-like change part curve of the DSC curve drawn during the second heating from 40°C to 200°C at 10°C/min and the straight line equidistant in the vertical axis direction from the extension line of each tangent was taken as the glass transition temperature (Tg). The glass transition temperatures of the samples of the other examples and comparative examples were also measured in the same manner. It can be said that the higher the glass transition temperature, the more excellent the heat resistance.

(Preparation of Unstretched and Stretched Samples)
First, an unstretched sample of polycarbonate resin was prepared using a vacuum compression molding machine. Specifically, it was prepared as follows. A polycarbonate resin was placed in a polyimide frame having a thickness of 25 to 150 μm, and sandwiched between two polyimide films, two aluminum plates, and two iron plates to obtain a laminate. At this time, the laminate was laminated so that the laminate was stacked in the following order: iron plate, aluminum plate, polyimide film, polyimide frame, polyimide film, aluminum plate, iron plate. The above laminate was set in a vacuum compression molding machine (manufactured by Shinto Metal Industries, SFV-30 type) and preheated for 10 minutes at a predetermined temperature shown in Table 1 under reduced pressure (10 kPa), and then compressed for 5 minutes at the above-mentioned predetermined temperature under a press pressure of 1 to 10 MPa while maintaining the reduced pressure condition. After releasing the vacuum and the press pressure, the compressed laminate was transferred to a cooling compression molding machine (AYS-10 model, manufactured by Shinto Metal Industries Co., Ltd.) and cooled and solidified to obtain a pressed film having a thickness of 20 to 250 μm. The obtained pressed film was aged for 24 hours in a constant temperature and humidity room at 23° C. and a humidity of 50%, to obtain an unstretched sample.

Next, the unstretched sample was cut to a width of 20-30 mm and a length of 50 mm, and placed in a tensile test fixture. The tensile test fixture was set in a Shimadzu Corporation test machine (product name: Autograph AG-5kNXPlus) connected to a thermostatic bath (product name: TCR1W-200T), and uniaxial free stretching was performed under the following conditions. The stretching conditions were chuck distance of 30 mm, stretching temperature of Tg+20°C, stretching speed of 500 mm/min, and stretch ratio of 100%. After uniaxial free stretching, the sample was immediately taken out to room temperature and cooled, and then aged for 24 hours in a thermostatic and humidity-controlled room at 23°C and 50% humidity to obtain a stretched film with a thickness of 10-200 μm. Several stretched films were produced using the above procedure. The thickness of each film was then measured using a thickness gauge ("Digimatic Thickness Gauge" manufactured by Mitutoyo Corporation).

(Measurement of in-plane retardation and orientation birefringence)
The 100% uniaxially stretched film was used to measure the in-plane retardation and orientation birefringence as follows. First, for each stretched film, the absolute value of the in-plane retardation at a wavelength of 587 nm was measured using a retardation measuring device manufactured by Oji Scientific Instruments (product name "KOBRA-WR"). Then, the orientation birefringence was calculated using the obtained absolute value of the in-plane retardation and the thickness of each stretched film. The absolute value of the in-plane retardation converted into a thickness of 100 μm was calculated using the obtained orientation birefringence. Note that the orientation birefringence, the absolute value of the in-plane retardation, the absolute value of the in-plane retardation converted into a thickness of 100 μm, and the thickness of the stretched film satisfy the following formulas (A), (B), and (C).
Δn=nx-ny (A)
Re = Δn × d (B)
Re ₁₀₀ (nm) = Δn×1.0×10 ⁵ (C)
(Δn: orientation birefringence, nx: refractive index in the stretching direction, ny: refractive index in the sample plane perpendicular to the stretching direction, Re: absolute value of in-plane retardation, Re ₁₀₀ : absolute value of in-plane retardation converted to a thickness of 100 μm, d: thickness of the stretched film)

(Measurement of photoelastic coefficient)
The unstretched sample obtained above was cut into a width of 6 mm and a length of 50 mm, and the photoelastic coefficient was measured as follows. For details of the measurement method, refer to Polymer Engineering and Science 1999, 39, 2349-2357. Specifically, it is as follows. The above sample was placed in a film tensioning device (manufactured by Imoto Manufacturing Co., Ltd.) installed in a temperature and humidity constant room at 23°C and 50% humidity so that the chuck distance was 20 mm. Next, the birefringence measuring device (manufactured by Otsuka Electronics, product name "RETS-100") was placed so that the light path of the birefringence measuring device was located at the center of the above sample. The birefringence of the test piece was measured at a wavelength of 550 nm while applying a stretching stress with a chuck distance of 40 mm and a chuck movement speed of 0.1 mm/min. From the relationship between the measured birefringence and tensile stress, the photoelastic coefficient (Pa ^-1 ) was calculated using the least squares method. For the calculation, data in which the tensile stress σ was 2.5 MPa≦σ≦10 MPa was used. The birefringence, tensile stress, and photoelastic coefficient satisfy the following formulas (D) and (E).
Δn=nx-ny (D)
C = Δn / σ (E)
(Δn: birefringence, nx: refractive index in the stretching direction, ny: refractive index in the direction perpendicular to the stretching direction within the sample plane, C: photoelastic coefficient, σ: stretching stress)

(Measurement of refractive index)
Using the unstretched sample obtained above, the refractive index was measured using a Metricon Prism Coupler (Model 2010) in a constant temperature and humidity environment of 23° C. The refractive index was measured at the following three wavelengths (532.0 nm, 632.8 nm, and 824.0 nm), and the refractive index at a wavelength of 632.8 nm is shown in Table 1 as a representative value.

[Synthesis Example 1]
(4,5-epoxy-tricyclo[ ^6.2.1.02.7 ]undecane)
Under an argon atmosphere, tricyclo[6.2.1.0 ^2.7 ]undec-4-ene (24.1 g, 162.4 mmol), sodium hydrogen carbonate (14.7 g, 175.4 mmol), and chloroform (770 mL) were added to a 2 L four-neck flask, and the mixture was stirred with a mechanical stirrer using a stirring blade. The reaction solution was cooled by immersing it in an ice bath. m-Chloroperbenzoic acid (45.6 g, 185.2 mmol) was added in three portions. After the addition was completed, the mixture was gradually warmed to room temperature while still immersed in ice water. After stirring for 19 hours, the reaction solution was filtered under reduced pressure, and the residue was rinsed with chloroform (500 mL x 3). The filtrate was washed with saturated aqueous sodium thiosulfate solution (500 mL), saturated aqueous sodium hydrogen carbonate solution (500 mL), and saturated saline solution (500 mL), and dried over sodium sulfate. The dried organic layer was concentrated using an evaporator. The resulting concentrate was subjected to column chromatography using 318 g of aminosilica gel to obtain the target product as a colorless transparent liquid (25.6 g).

[Synthesis Example 2]
(4,5-dihydroxy-tricyclo[ ^6.2.1.02.7 ]undecane)
In a 500 mL four-neck flask, 4,5-epoxy-tricyclo[6.2.1.0 ^2.7 ]undecane (25.2 g, 6.09 mmol), ion-exchanged water (250 mL), and a stirrer were placed and stirred with a magnetic stirrer. The reaction solution was immersed in an oil bath and heated to an external temperature of 100°C. After stirring for 18 hours, the reaction solution was concentrated under reduced pressure using an evaporator and azeotroped three times with acetonitrile to obtain the target product as a white solid (25.0 g).

[Synthesis Example 3]
(4,5-carbonato-tricyclo[ ^6.2.1.02.7 ]undecane (TCUC))
Under argon flow, 4,5-dihydroxy-tricyclo[6.2.1.0 ^2.7 ]undecane (20.0 g, 110.0 mmol) and dehydrated tetrahydrofuran (200 mL) were added to a 500 mL four-neck flask, and the mixture was stirred with a mechanical stirrer using a stirring blade. The reaction solution was cooled by immersing it in a salt ice bath. Ethyl chloroformate (23.8 g, 219.1 mmol) was slowly added. Triethylamine (29.9 g, 295.8 mmol) was diluted in dehydrated toluene (65 mL) and slowly dropped using a dropping funnel. After stirring at room temperature for 18 hours, 40 g of silica gel was filled into a Kiriyama funnel, and the reaction solution was slowly poured into it. After passing the liquid through the funnel, the filter cake was rinsed with tetrahydrofuran/toluene (2/1) (200 mL x 5), and the filtrate was concentrated using an evaporator. The obtained concentrate was dissolved in chloroform (250 mL), ion-exchanged water (250 mL) was added and stirred, and the organic layer was collected. The collected organic layer was washed with ion-exchanged water (250 mL), and the washed organic layer was dried with magnesium sulfate and filtered. The filtrate was concentrated with an evaporator. The obtained concentrate was dissolved again in chloroform (46 mL) and slowly dropped into ice-cooled heptane (460 mL). After stirring for 30 minutes, the precipitated solid was collected by vacuum filtration and dried under reduced pressure at 40° C. for 48 hours to obtain the target product as a white solid (15.1 g).

[Example 1]
4,5-carbonato-tricyclo[6.2.1.0 ^2.7 ]undecane (hereinafter also referred to as TCUC) (2.65 g, 12.8 mmol) was weighed out into a 50 mL three-neck flask, and the flask was replaced with nitrogen. After adding dehydrated m-xylene (11.2 g) into the flask, the flask was immersed in an oil bath and heated to 60°C, and the monomer was completely dissolved by stirring using a magnetic stirrer. Separately, potassium tert-butoxide solution (1.0 M, 0.30 mL, 0.30 mmol) was weighed out into a dried 30 mL Schlenk flask and diluted with dehydrated m-xylene (2.70 mL) to prepare an initiator solution. While stirring the monomer solution, 0.98 mL of the prepared initiator solution was added, and the mixture was stirred at 60°C for 3 hours. 0.0213 g of acetic acid was added to stop the reaction (polymerization solution). A portion of the polymerization solution was sampled and diluted with chloroform-d to measure the ¹ H-NMR spectrum. The monomer conversion was calculated to be 95% from the integrated intensity ratio of the peak derived from the monomer at 3.9 to 4.1 ppm and the peak derived from the polymer at 4.5 to 5.1 ppm.

Next, to evaluate the methanol insoluble matter, a reprecipitation operation was performed as follows. 10.3 g of the polymerization liquid was sampled and diluted with 41.0 g of chloroform. The diluted liquid was added to 516 g of methanol to precipitate the polymer. The precipitated polymer was collected by vacuum filtration and washed with 35.5 g of methanol. The obtained polymer was vacuum dried at 40°C for 6 hours to obtain a polymer. The Mw of the obtained homopolymer was 20,000 and the glass transition temperature was 166°C.

[Example 2]
Except for changing the amount of the polymerization initiator to 0.10 mol %, the polymerization reaction was carried out in the same manner as in Example 1. The resulting homopolymer had an Mw of 136,000 and a glass transition temperature of 166° C.

[Example 3]
After replacing the atmosphere in a 50 mL separable flask equipped with a stirring blade with nitrogen, a m-xylene solution of TCUC (49.8 g; 20 wt% TCUC, 47.7 mmol) previously dehydrated using molecular sieves 4A was weighed and added, and the flask was immersed in a water bath to adjust the internal temperature to 25°C. Separately, a potassium tert-butoxide solution (1.0 M, 0.49 mL, 0.49 mmol) and benzyl alcohol (0.11 g, 0.98 mmol) were weighed into a dried 30 mL Schlenk flask, and the solution was diluted with dehydrated m-xylene (4.30 mL) to prepare an initiator solution. While stirring the monomer solution, 0.18 mL of the prepared initiator solution was added, and the mixture was stirred at 25°C for 5 minutes. Acetic acid (0.0087 g) was added to terminate the reaction (polymerization solution).

Next, to evaluate the methanol insoluble matter, a reprecipitation operation was performed as follows. 47.4 g of the polymerization liquid was sampled and added to 185.4 g of acetone to precipitate the polymer. After removing 200.4 g of the supernatant by decantation, 46.7 g of chloroform was added to redissolve the precipitated polymer. This polymer solution was added to 241.5 g of methanol to reprecipitate the polymer. The polymer was recovered by decantation and reduced pressure filtration, and washed with 35.5 g of methanol. The obtained polymer was vacuum dried at 100°C for 4 hours to obtain a polymer. The Mw of the obtained homopolymer was 184,000, and the glass transition temperature was 168°C.

[Example 4]
A polymerization reaction was carried out in the same manner as in Example 1, except that 9 mol % of TCUC and 91 mol % of trans-cyclohexene carbonate (hereinafter also referred to as t-CHC) were used as monomers and the amount of the polymerization initiator was 0.20 mol %. The Mw of the obtained copolymer was 51,000 and the glass transition temperature was 128° C.

[Example 5]
A polymerization reaction was carried out in the same manner as in Example 4, except that 20 mol % of TCUC and 80 mol % of t-CHC were used as monomers and the amount of the polymerization initiator was 0.10 mol %. The Mw of the obtained copolymer was 73,000 and the glass transition temperature was 138° C.

[Example 6]
After replacing the atmosphere in a 50 mL separable flask equipped with a stirring blade with nitrogen, a m-xylene solution of TCUC (28.3 g; 20 wt% TCUC, 27.1 mmol), t-CHC (3.89 g, 27.4 mmol), and dehydrated m-xylene (15.7 g) that had been previously dehydrated using molecular sieves 4A were weighed and added, and the flask was immersed in a water bath to adjust the internal temperature to 25°C. Separately, a potassium tert-butoxide solution (1.0 M, 0.30 mL, 0.30 mmol) was weighed into a dried 30 mL Schlenk flask and diluted with dehydrated m-xylene (2.70 mL) to prepare an initiator solution. While stirring the monomer solution, 0.52 mL of the prepared initiator solution was added, and the mixture was stirred at 25°C for 40 minutes. Acetic acid (0.00157 g) was added to stop the reaction (polymerization solution).

Next, to evaluate the methanol insoluble matter, a reprecipitation operation was performed as follows. 40.7 g of the polymerization liquid was sampled and diluted with 154.2 g of chloroform. The diluted liquid was added to 941 g of methanol to precipitate the polymer. The precipitated polymer was recovered by decantation and reduced pressure filtration, and washed three times with 261.9 g of methanol. The obtained polymer was vacuum dried at 100°C for 5 hours to obtain a polymer. The Mw of the obtained copolymer was 124,000, and the glass transition temperature was 150°C.

[Example 7]
A polymerization reaction was carried out in the same manner as in Example 6, except that a dehydrated m-xylene solution of TCUC (38.8 g; 20 wt% TCUC, 37.2 mmol), t-CHC (1.37 g, 9.64 mmol), and dehydrated m-xylene (5.18 g) were used. The Mw of the obtained copolymer was 85,000, and the glass transition temperature was 166°C.

[Comparative Example 1]
t-CHC (10.1 g, 70.8 mmol) was added to a 50 mL separable flask, and the atmosphere in the flask was replaced with nitrogen. m-Xylene (40.1 g) was added to the flask, and the flask was immersed in an oil bath and heated to an internal temperature of 60° C. while stirring with a mechanical stirrer and a stirring blade to completely dissolve the monomer. Separately, potassium tert-butoxide solution (1.0 M, 0.37 mL, 0.37 mmol) and benzyl alcohol (0.0796 g, 0.74 mmol) were weighed into a dried 30 mL Schlenk flask and diluted with 3.3 mL of m-xylene to prepare an initiator solution. While stirring the monomer solution, 0.26 mL of the prepared initiator solution was added at once, and the mixture was stirred at 60° C. for 3 hours. 0.0072 g of acetic acid was added to stop the reaction (polymerization solution).
Subsequently, in order to evaluate the methanol insoluble matter, a reprecipitation operation was carried out as follows. 0.59 g of the polymerization liquid was sampled and diluted by adding 1.51 g of m-xylene. The diluted liquid was added to 21.1 g of methanol to precipitate a polymer. The precipitated polymer was recovered by filtration under reduced pressure, and the obtained polymer was vacuum dried at 130° C. for 2 hours to obtain a homopolymer. The Mw of the obtained polymer was 68,000, and the glass transition temperature was 120° C.

The physical properties of the polycarbonate resins obtained in the examples and comparative examples are shown in Table 1.

Table 1 shows that the polycarbonate resin of the Example has a higher glass transition temperature than the polycarbonate resin of the Comparative Example, and therefore has high dimensional stability in a high-temperature environment and excellent heat resistance. Table 1 also shows that the polycarbonate resin of the Example has a small photoelastic coefficient and low birefringence.

The polycarbonate resin, polycarbonate resin composition, and optical molded articles containing them of the present invention have industrial applicability in the fields of various optical materials such as optical lens materials, optical devices, materials for optical components, and display materials.

Claims (9)

A structural unit represented by the following formula (1):
(In formula (1),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are hydrogen atoms;
X is an unsubstituted, mono- or di-substituted methylene group;
n is an integer from 0 to 2.
A polycarbonate resin having the formula: The polycarbonate resin according to claim 1 , wherein n is 0 or 1. 3. The polycarbonate resin according to claim 1, which has a weight average molecular weight (Mw) in terms of polystyrene measured by size exclusion chromatography (SEC) of 10,000 or more and 500,000 or less . The polycarbonate resin according to any one of claims 1 to 3 , which has a glass transition temperature (Tg) measured by a differential scanning calorimeter of 125°C or more and 200°C or less. A polycarbonate resin composition comprising the polycarbonate resin according to any one of claims 1 to 4 and an antioxidant. An optical part comprising the polycarbonate resin according to any one of claims 1 to 4 or the polycarbonate resin composition according to claim 5 . Use of the polycarbonate resin according to any one of claims 1 to 4 or the polycarbonate resin composition according to claim 5 as a material for optical parts. A method for producing the polycarbonate resin according to any one of claims 1 to 4 , comprising reacting a compound represented by the following formula (2):
(In formula (2), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , X, and n are as defined in formula (1).)
The production method includes a polymerization step of ring-opening polymerizing a cyclic carbonate represented by the following formula (1): A method for producing the polycarbonate resin according to any one of claims 1 to 4 , comprising reacting a compound represented by the following formula (3):
(In formula (3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , X, and n are as defined in formula (1).)
and a polymerization step of reacting an epoxide represented by the following formula (I) with carbon dioxide to obtain the polycarbonate resin.