CN115677999B - Polycarbonate and preparation method and application thereof - Google Patents

Abstract

The embodiments of the present application relate to a polycarbonate and a preparation method and application thereof. The polycarbonate of the present application comprises a carbonate group, and the dihydroxy compound forming the carbonate group comprises a dihydroxy compound in which two hydroxyl-containing substituted or unsubstituted aromatic groups are connected by M, and the M forms a ring structure with a divalent _X3 and two other substituted or unsubstituted aromatic groups, and the two hydroxyl-containing substituted or unsubstituted aromatic groups are not connected to each other except the M or are connected to each other via _X4 .

Description

Polycarbonate and its preparation method and application

Technical Field

The embodiments of the present application relate to the technical field of optical materials, and in particular to polycarbonate and a preparation method and application thereof.

Background Art

For example, various terminal consumer electronic products such as tablet computers, laptops, digital cameras, mobile phones, wearable electronic devices, virtual reality devices, etc. require optical products with excellent optical performance in multiple application scenarios, such as camera lens materials, delay sheet materials in mobile phone display screens, etc. High-refractive polycarbonate (PC) optical resins are widely used in the preparation of various optical products due to their advantages such as light weight, impact resistance, high transparency, and easy processing and molding.

On the one hand, the current mainstream camera module manufacturers usually need polycarbonate materials with high refractive index (even refractive index higher than 1.63). However, the higher the refractive index of the polycarbonate material, the more serious the dispersion. Therefore, the Abbe number of the polycarbonate material with high refractive index is often relatively low. In addition, the refractive index is usually increased by increasing the number of aromatic rings in the polycarbonate material, but this leads to residual stress in the material during the injection molding process, resulting in stress birefringence, and ghosting is prone to occur during the imaging process, affecting the optical performance of optical products made of polycarbonate.

Therefore, there is still room for improvement in achieving high refractive index, low dispersion and low birefringence at the same time.

In addition, in the processing and use environment of polycarbonate materials, they usually need to withstand high heat, such as heat from processing and molding and heat generated near light sources, etc. Therefore, in order to ensure the performance stability of polycarbonate materials, polycarbonate materials are often required to have excellent heat resistance.

Summary of the invention

In view of this, a polycarbonate is proposed, which can take into account a high refractive index (for example, it can reach greater than 1.56, or even above 1.63), a low dispersion (for example, it can reach above 17, or even above 19), a high heat resistance and a low birefringence (for example, it can reach below 50nm under d light when the thickness is 1mm).

A method for preparing polycarbonate is also proposed. The method can easily obtain polycarbonate having high refractive index, low dispersion, high heat resistance and low birefringence, and the process is simple and convenient for large-scale production.

A resin composition is also proposed, which can take into account high refractive index, low dispersion, high heat resistance and low birefringence, and has a wide range of uses, for example, it can be used to prepare the above-mentioned various molded products that require at least one of the above-mentioned properties.

Also provided is an optical product and a device including the optical product, wherein the optical product can achieve high refractive index, low dispersion, high heat resistance and low birefringence.

In a first aspect, an embodiment of the present application provides a polycarbonate, wherein the polycarbonate comprises a carbonate group, wherein the dihydroxy compound forming the carbonate group comprises a dihydroxy compound in which two hydroxyl-containing substituted or unsubstituted aromatic groups are connected by M, wherein M forms a cyclic structure with a divalent X ₃ and two other substituted or unsubstituted aromatic groups, and the two hydroxyl-containing substituted or unsubstituted aromatic groups are not connected to each other except the M or are connected to each other via X ₄ ;

M represents a carbon atom, a silicon atom, a germanium atom or a tin atom;

_X3 represents an oxy group, a thiol group, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms, or a carbonyl group;

_X4 represents a direct bond, oxygen, sulfur, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms.

In this case, the polycarbonate of the present application can take into account high refractive index, low dispersion, high heat resistance and low birefringence. Specifically, in the present application, the presence of each aromatic ring structure can increase the refractive index of the polycarbonate, and at the same time, connecting the aromatic ring structures by _X3 and M as a bridging group can not only help to improve the refractive index of the material, but also alleviate the internal birefringence of the material, and effectively reduce dispersion (increase the Abbe number of the polymer).

According to the first aspect, in a first possible implementation manner of the polycarbonate, the cyclic structure is a 6- to 10-membered ring.

In this case, the polycarbonate of the present application can better balance high refractive index, low dispersion, high heat resistance and low birefringence.

According to the first aspect, in the first or second possible implementation of the polycarbonate, the polycarbonate comprises at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II):

In formula (I) and formula (II),

X ₁ and X ₂ each independently represent a substituted or unsubstituted linear or branched alkylene group having 1 to 8 carbon atoms;

X ₃ , X ₄ , and M are the same as above;

R ₁ and R ₂ each independently represent hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, hydroxyl, ester, cyano, amino, thiol, or an atom or atomic group that can replace the above groups;

R ₃ to R ₈ each independently represents hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, hydroxyl, ester, cyano, amino, thiol, or an atom or atomic group that can replace the above groups, and at least two adjacent substituents in R ₃ to R ₈ can be connected to each other to form a ring structure;

a and b are each independently selected from integers of 0 to 5;

p1 and p2 are each independently selected from integers of 1 to 3;

m ₁ and m ₂ are each independently selected from integers of 1-4.

In this case, the polycarbonate of the present application can better balance high refractive index, low dispersion, high heat resistance and low birefringence. Specifically, in the present application, in the structural units shown in formula (I) and formula (II), the presence of the aromatic ring structure can better improve the refractive index of the polycarbonate, and at the same time, connecting the aromatic ring structures by _X3 and M as bridging groups can not only help to improve the refractive index of the material, but also better alleviate the internal birefringence of the material, and at the same time effectively reduce the dispersion (increase the Abbe number of the polymer).

According to the first aspect, in any one of the first to third possible implementations of the polycarbonate, _X3 represents oxygen, sulfur, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted amino group having 1 to 10 carbon atoms, a substituted or unsubstituted silylene group having 1 to 16 carbon atoms and 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group having 1 to 10 carbon atoms, an unsubstituted linear or branched alkylene group having 1 to 6 carbon atoms, or a carbonyl group.

In this case, the polycarbonate of the present application can have a higher refractive index, lower dispersion, high heat resistance, and lower birefringence, and can be obtained more easily.

According to the first aspect, in the third or fourth possible implementation of the polycarbonate, the content of at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II) is greater than 10 mol% relative to the total molar amount of all repeating units of the polycarbonate.

In this case, the polycarbonate of the present application can take into account higher refractive index, lower dispersion, high heat resistance and lower birefringence.

According to the first aspect, in a fifth possible implementation of the polycarbonate, the content of at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II) is less than 80 mol% relative to the total molar amount of all repeating units of the polycarbonate.

In this case, the polycarbonate of the present application can further have low cost.

According to the first aspect, in any one of the first to sixth possible implementations of the polycarbonate, the polycarbonate further comprises at least one structural unit selected from the structural unit represented by formula (III), the structural unit represented by formula (IV), and the structural unit represented by formula (V):

In formula (III), formula (IV) and formula (V),

X ₁ , X ₂ , a, and b are the same as those in formula (I) and formula (II);

Y represents oxygen, sulfur, a sulfoxide group, a sulfone group, a substituted or unsubstituted linear or branched alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 20 carbon atoms, a substituted or unsubstituted fluorenylene group, a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 carbon atoms;

_R9 , _R10 , and _R11 each independently represent hydrogen, hydroxyl, substituted or unsubstituted linear or branched alkyl having 1 to 6 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 10 carbon atoms, substituted or unsubstituted linear or branched alkenyl having 2 to 6 carbon atoms, substituted or unsubstituted linear or branched alkoxy having 1 to 6 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, or substituted or unsubstituted heteroaryl having 2 to 30 carbon atoms;

_R12 represents a substituted or unsubstituted linear or branched alkylene group having 1 to 15 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 15 carbon atoms, or a substituted or unsubstituted linear or branched ether group having 1 to 10 carbon atoms;

Z ₁ and Z ₂ each independently represent oxygen, sulfur, or a direct bond;

m ₃ , m ₄ , and m ₅ are each independently selected from integers of 1-2.

In this case, the polycarbonate of the present application can more balancedly take into account high refractive index, low dispersion, high heat resistance and lower birefringence, and has low cost.

According to the first aspect, in a seventh possible implementation of the polycarbonate, relative to the total molar amount of all repeating units of the polycarbonate, the content of at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II) is 30 to 60 mol%, and the content of at least one structural unit selected from the structural unit represented by formula (III), the structural unit represented by formula (IV), and the structural unit represented by formula (V) is 40 to 85 mol%.

In this case, the polycarbonate of the present application can more balancedly take into account higher refractive index, lower dispersion, high heat resistance and lower birefringence, and has low cost.

According to the first aspect, in any one of the first to eighth possible implementations of the polycarbonate, the weight average molecular weight of the polycarbonate is 10,000 g/mol to 200,000 g/mol.

In this case, the polycarbonate of the present application has higher heat resistance, mechanical properties and excellent processability.

According to the first aspect, in any one of the first to ninth possible implementations of the polycarbonate, the refractive index of the polycarbonate is greater than 1.56.

In this case, the polycarbonate of the present application has a further increased refractive index.

According to the first aspect, in any one of the first to tenth possible implementations of the polycarbonate, the Abbe number of the polycarbonate is greater than 17.

In this case, the polycarbonate of the present application has further reduced dispersion.

According to the first aspect, in any one of the first to eleventh possible implementations of the polycarbonate, the glass transition temperature of the polycarbonate is above 135°C.

In this case, the polycarbonate of the present application has further increased heat resistance.

According to the first aspect, in any one of the first to twelfth possible implementations of the polycarbonate, the birefringence of the polycarbonate under d-light when the thickness is 1 mm is less than 50 nm.

In this case, the polycarbonate of the present application has a further reduced birefringence.

In a second aspect, an embodiment of the present application provides a method for preparing polycarbonate, comprising: subjecting a dihydroxy compound and a carbonate diester compound to transesterification polycondensation under the action of a catalyst to obtain polycarbonate,

The dihydroxy compound includes a dihydroxy compound in which two hydroxyl-containing substituted or unsubstituted aromatic groups are connected by M, wherein M forms a ring structure with a divalent X ₃ and two other substituted or unsubstituted aromatic groups, and the two hydroxyl-containing substituted or unsubstituted aromatic groups are not connected to each other except the M or are connected to each other via X ₄ ;

M represents a carbon atom, a silicon atom, a germanium atom or a tin atom;

_X3 represents an oxy group, a thiol group, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms, or a carbonyl group;

_X4 represents a direct bond, oxygen, sulfur, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms.

In this case, the preparation method of the present application can easily obtain polycarbonate that can take into account high refractive index, low dispersion, high heat resistance and low birefringence, and the process is simple and convenient for large-scale production.

According to the second aspect, in a first possible implementation of the preparation method, the ring structure is a 6- to 10-membered ring.

In this case, the polycarbonate of the present application can better balance high refractive index, low dispersion, high heat resistance and low birefringence.

According to the second aspect, in the first or second possible implementation of the preparation method, it comprises: subjecting at least one dihydroxy compound selected from the dihydroxy compound represented by formula (1) and the dihydroxy compound represented by formula (2) to transesterification polycondensation with a carbonic acid diester compound under the action of a catalyst to obtain a polycarbonate:

In formula (1) and formula (2),

X ₁ and X ₂ each independently represent a substituted or unsubstituted linear or branched alkylene group having 1 to 8 carbon atoms;

X ₃ , X ₄ , and M are the same as above;

R ₁ and R ₂ each independently represent hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, hydroxyl, ester, cyano, amino, thiol, or an atom or atomic group that can replace the above groups;

R ₃ to R ₈ each independently represents hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, hydroxyl, ester, cyano, amino, thiol, or an atom or atomic group that can replace the above groups, and at least two adjacent substituents in R ₃ to R ₈ can be connected to each other to form a ring structure;

a and b are each independently selected from integers of 0 to 5;

p1 and p2 are each independently selected from integers of 1 to 3;

m ₁ and m ₂ are each independently selected from integers of 1-4.

In this case, the polycarbonate of the present application can better balance high refractive index, low dispersion, high heat resistance and low birefringence.

According to the second aspect, in any one of the first to third possible implementations of the preparation method, the preparation method comprises: further subjecting at least one dihydroxy compound selected from the dihydroxy compound represented by formula (3), the dihydroxy compound represented by formula (4), and the dihydroxy compound represented by formula (5) to transesterification polycondensation with a carbonate diester compound:

In formula (3), formula (4) and formula (5),

X ₁ , X ₂ , a, and b are the same as those in formula (1) and formula (2);

Y represents oxygen, sulfur, a sulfoxide group, a sulfone group, a substituted or unsubstituted linear or branched alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 20 carbon atoms, a substituted or unsubstituted fluorenylene group, a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 carbon atoms;

_R9 , _R10 , and _R11 each independently represent hydrogen, hydroxyl, substituted or unsubstituted linear or branched alkyl having 1 to 6 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 10 carbon atoms, substituted or unsubstituted linear or branched alkenyl having 2 to 6 carbon atoms, substituted or unsubstituted linear or branched alkoxy having 1 to 6 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, or substituted or unsubstituted heteroaryl having 2 to 30 carbon atoms;

_R12 represents a substituted or unsubstituted linear or branched alkylene group having 1 to 15 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 15 carbon atoms, or a substituted or unsubstituted linear or branched ether group having 1 to 10 carbon atoms;

Z ₁ and Z ₂ each independently represent oxygen, sulfur, or a direct bond;

m ₃ , m ₄ , and m ₅ are each independently selected from integers of 1-2.

In this case, the preparation method of the present application can obtain polycarbonate that can more balancedly take into account high refractive index, low dispersion, high heat resistance and low birefringence at a lower cost.

According to the second aspect, in any one of the first to fourth possible implementations of the preparation method, the carbonic acid diester compound is at least one selected from diphenyl carbonate, ditolyl carbonate, dichlorophenyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate and dicyclohexyl carbonate.

In this case, the preparation method of the present application can be carried out more smoothly.

According to the second aspect, in any one of the first to fifth possible implementations of the preparation method, the catalyst is an alkaline substance or an ionic liquid catalyst.

In this case, the preparation method of the present application can be carried out more efficiently.

According to the second aspect, in any one of the first to sixth possible implementations of the preparation method, the ester exchange polycondensation is ester exchange melt polycondensation.

In this case, the preparation method of the present application can more easily prepare the desired polycarbonate, is highly environmentally friendly, and is more convenient for large-scale production.

According to the second aspect, in any one of the first to seventh possible implementations of the preparation method, the amount of the carbonic acid diester compound is 0.97 to 1.2 moles relative to 1 mole of the total amount of all dihydroxy compounds.

In this case, the preparation method of the present application can have high environmental friendliness while ensuring easy preparation of the desired polycarbonate, and the production cost is lower.

In a third aspect, an embodiment of the present application provides a resin composition, characterized in that the resin composition comprises a polycarbonate according to any possible implementation of the first to thirteenth aspects of the first aspect or a polycarbonate prepared by a preparation method according to any possible implementation of the first to eighth aspects of the first aspect.

In this case, the resin composition of the present application can take into account high refractive index, low dispersion, high heat resistance and low birefringence, and has a wide range of uses, for example, it can be used to prepare the above-mentioned various molded products that require at least one of the above-mentioned properties.

In a fourth aspect, an embodiment of the present application provides an optical product, comprising a polycarbonate according to any possible implementation of the first to thirteenth aspects of the first aspect or a polycarbonate prepared by a preparation method according to any possible implementation of the first to eighth aspects of the first aspect.

In this case, the optical product of the present application can have high refractive index, low dispersion, high heat resistance and low birefringence.

According to the fourth aspect, in a first possible implementation of the optical product, the optical product includes an optical lens, an optical film, an optical disc, a light guide plate or a display panel.

In this case, the optical product of the present application can better exert its excellent optical performance.

According to the fourth aspect, in a second possible implementation of the optical product, the optical lens includes a spectacle lens, a camera lens, a sensor lens, a lighting lens, and an imaging lens.

In this case, the optical lens of the present application can better exert its excellent optical performance.

In a fifth aspect, an embodiment of the present application provides a device comprising an optical product according to any one of the first to third possible implementation methods of the first aspect.

In this case, the optical product installed in the device of the present application can take into account high refractive index, low dispersion, high heat resistance and low birefringence, so that the device has excellent optical performance.

According to the fifth aspect, in a first possible implementation of the device, the device includes a device body and a camera module mounted on the device body, and the camera module includes a lens as the optical product.

In this case, the lens of the camera module installed in the device of the present application can take into account high refractive index, low dispersion, high heat resistance and low birefringence, so that the camera module has excellent imaging performance.

DETAILED DESCRIPTION

Various exemplary embodiments, features and aspects of the present application are described in detail below. The word "exemplary" used herein means "used as an example, embodiment or illustrative". Any embodiment described herein as "exemplary" is not necessarily to be interpreted as being superior or better than other embodiments.

In addition, in order to better illustrate the present application, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that the present application can also be implemented without certain specific details. In some instances, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

<First aspect>

In order to solve the above technical problems, the present application provides a polycarbonate, the polycarbonate comprises a carbonate group, the dihydroxy compound forming the carbonate group comprises a dihydroxy compound in which two hydroxyl-containing substituted or unsubstituted aromatic groups are connected by M, the M forms a cyclic structure with a divalent X ₃ and two other substituted or unsubstituted aromatic groups, the two hydroxyl-containing substituted or unsubstituted aromatic groups are not connected to each other except the M or are connected to each other via X ₄ ;

M represents a carbon atom, a silicon atom, a germanium atom or a tin atom;

_X3 represents an oxy group, a thiol group, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms, or a carbonyl group;

_X4 represents a direct bond, oxygen, sulfur, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms.

In this case, the polycarbonate of the present application can take into account high refractive index, low dispersion, high heat resistance and low birefringence. Specifically, in the present application, the presence of each aromatic ring structure can increase the refractive index of the polycarbonate, and at the same time, connecting the aromatic ring structures by _X3 and M as a bridging group can not only help to improve the refractive index of the material, but also alleviate the internal birefringence of the material, and effectively reduce dispersion (increase the Abbe number of the polymer).

In some preferred embodiments, the ring structure formed by M, _X3 and two other substituted or unsubstituted aromatic groups is a 6- to 10-membered ring.

In some preferred embodiments, the polycarbonate of the present application preferably includes at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II):

In formula (I) and formula (II), X ₁ and X ₂ each independently represent a substituted or unsubstituted linear or branched alkylene group having 1 to 8 carbon atoms.

There are no particular restrictions on the substituents of the alkylene groups of _X1 and _X2 , and examples include, but are not limited to, halogen groups such as fluorine, chlorine, and bromine; aryl groups such as phenyl and naphthyl; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthoxy; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl; mercapto; cyano; amino; ester; amide, and the like.

In some preferred embodiments, X ₁ and X ₂ each independently represent preferably a substituted or unsubstituted linear or branched alkylene group having 1 to 5 carbon atoms. In some more preferred embodiments, from the viewpoint of improving the performance stability of the polymer, X ₁ and X ₂ each independently represent more preferably a methylene group, an ethylene group, a n-propylene group, an isopropylene group, an n-butylene group, or a sec-butylene group.

In formula (I) and formula (II), _X3 represents oxygen, sulfur, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms, or a carbonyl group.

In the present application, the terms "imino", "silylene" and "phosphino" are those known in the art. For example, "imino" can be represented by -(NQ) _n1- , wherein R is hydrogen or _alkylene ; "silylene" can be represented by -( _SiQ1Q2 ) _n2- , wherein _Q1 and _Q2 are each independently hydrogen or alkylene; "phosphino" can be represented _by - _{( PQ3Q4Q5} ) _n3- , wherein _Q3 , _Q4 and _Q5 are each independently hydrogen or alkylene.

There are no particular restrictions on the substituents of the imino, silylene and phosphorous groups of X ₃ , including but not limited to: halogen groups such as fluorine, chlorine and bromine; alkyl groups such as methyl, ethyl and propyl; aryl groups such as phenyl and naphthyl; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthyl; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl; mercapto; cyano, etc. There are no particular restrictions on the substituents of the alkylene (straight chain, branched chain and cyclic) of X ₃ , including but not limited to: halogen groups such as fluorine, chlorine and bromine; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthyl; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl; mercapto; cyano; amino; ester group; amide group, etc.

In some preferred embodiments, from the viewpoint that the polycarbonate can have a higher refractive index, lower dispersion, high heat resistance and lower birefringence, and is more easily obtained, _X3 in the present application preferably represents oxygen, sulfur, disulfide, sulfoxide, sulfone, substituted or unsubstituted imino having 1 to 10 carbon atoms, substituted or unsubstituted silylene having 1 to 16 carbon atoms and 1 to 3 silicon atoms, substituted or unsubstituted phosphorous having 1 to 10 carbon atoms, unsubstituted linear or branched alkylene having 1 to 6 carbon atoms, or carbonyl. In some more preferred embodiments, from the viewpoint that the desired effect can be further obtained, _X3 more preferably represents oxygen, sulfur, sulfoxide, sulfone, methylene, ethylene, n-propylene, isopropylene. In some particularly preferred embodiments, _X3 particularly preferably represents sulfur, because it can better improve the optical properties of polycarbonate, such as the refractive index, and reduce the internal stress of the material through the flexibility brought by the sulfur atom, relieve the internal birefringence of the material, and regulate the dispersion to avoid serious dispersion problems of the material.

In formula (II), _X4 represents a direct bond, oxygen, sulfur, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms.

There are no particular restrictions on the substituents of the imino, silylene and phosphorous groups of _X4 , including but not limited to halogen groups such as fluorine, chlorine and bromine; alkyl groups such as methyl, ethyl and propyl; aryl groups such as phenyl and naphthyl; aryl groups such as phenyl and naphthyl; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthyl; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl; mercapto; cyano, etc. There are no particular restrictions on the substituents of the alkylene (straight chain, branched chain and cyclic) of _X4 , including but not limited to halogen groups such as fluorine, chlorine and bromine; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthyl; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl; mercapto; cyano; amino; ester group; amide group, etc.

In some preferred embodiments, _X4 preferably represents a direct bond, sulfur or oxygen, more preferably a direct bond or sulfur. When _X4 is a direct bond, the polymer has better optical properties, and mechanical and heat resistance properties can also be improved. When _X4 is sulfur or oxygen (especially sulfur), the optical properties of the polymer can be further improved, a higher refractive index can be obtained, and a higher Abbe number can also be obtained.

In formula (I) and formula (II), M represents a carbon atom, a silicon atom, a germanium atom or a tin atom.

In some preferred embodiments, from the viewpoint of easier availability, M preferably represents a carbon atom.

In formula (I) and formula (II), R ₁ and R ₂ each independently represent hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, hydroxy, ester, cyano, amino, thiol, or an atom or atomic group which may substitute for the above groups.

In some preferred embodiments, R ₁ and R ₂ each independently represent preferably hydrogen, methyl or phenyl, because, in this case, the mechanical properties of the material can be further adjusted, the refractive index of the material can be further improved, and/or the heat resistance can be further improved.

In formula (I) and formula (II), R ₃ to R ₈ each independently represent hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, hydroxyl, ester, cyano, amino, thiol, or an atom or atomic group that can replace the above groups, and at least two adjacent substituents among R ₃ to R ₈ can be connected to each other to form a ring structure.

In some preferred embodiments, R ₃ to R ₈ each independently represent hydrogen. In other preferred embodiments, R ₃ and R ₄ are connected to form a benzo group and/or R ₇ and R ₈ are connected to form a benzo group, because the introduction of condensed rings can increase the refractive index of the material and improve the heat resistance of the material.

In formula (I) and formula (II), a and b are each independently selected from integers of 0 to 5. In some preferred embodiments, from the viewpoint of better achieving the performance stability of the polymer, a and b are preferably not both 0. In some more preferred embodiments, a and b are each independently 1 or 2.

In formula (I) and formula (II), p1 and p2 are each independently selected from integers of 1 to 3, preferably 1 or 2.

In formula (I) and formula (II), m ₁ and m ₂ are each independently selected from integers of 1 to 4, and are preferably 1 or 2.

In some specific embodiments, the polycarbonate of the present application preferably includes at least one structural unit selected from the structural units represented by formulae (I-1) to (I-16) and (II-1) to (II-12).

In the present application, there is no particular limitation on the content of at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II), and it can be appropriately adjusted according to actual needs.

In some preferred embodiments, from the viewpoint that the polycarbonate can have a higher refractive index, lower dispersion, high heat resistance and lower birefringence, the content of at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II) is preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 30 mol% or more, and particularly preferably 40 mol% or more, relative to the total molar amount of all repeating units of the polycarbonate.

In other preferred embodiments, from the viewpoint that the polycarbonate can have further low cost while ensuring the desired optical properties, the content of at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II) is 80 mol% or less, more preferably 75 mol% or less, further preferably 70 mol% or less, and particularly preferably 65 mol% or less, relative to the total molar amount of all repeating units of the polycarbonate.

In the present application, there is no particular limitation on the specific types of other structural units that the polycarbonate may contain in addition to at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II), and various structural units conventionally known in the art may be used.

In some preferred embodiments, from the viewpoint that the polycarbonate of the present application can more balancedly take into account high refractive index, low dispersion, high heat resistance and low birefringence, and has low cost, as other structural units, the polycarbonate of the present application further includes at least one structural unit selected from the structural unit represented by formula (III), the structural unit represented by formula (IV), and the structural unit represented by formula (V):

In formula (III), Y preferably represents oxygen, sulfur, a sulfoxide group, a sulfone group, a substituted or unsubstituted linear or branched alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 20 carbon atoms, a substituted or unsubstituted fluorenylene group, a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 carbon atoms.

There are no particular restrictions on the substituents of the linear or branched alkylene and cycloalkylene groups of Y, and examples include but are not limited to: halogen groups such as fluorine, chlorine, and bromine; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthoxy; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl groups; mercapto groups; cyano groups; amino groups; ester groups; amide groups, etc. There are no particular restrictions on the substituents of the fluorenylene, arylene, and heteroarylene groups of Y, and examples include but are not limited to: halogen groups such as fluorine, chlorine, and bromine; alkyl groups such as methyl, ethyl, and propyl; aryl groups such as phenyl and naphthyl; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthoxy; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl groups; mercapto groups; cyano groups; amino groups; ester groups; amide groups, etc. Here, the heteroatoms in the "heteroarylene" include but are not limited to nitrogen, sulfur, oxygen, boron, and silicon.

In formula (III), _R9 and _R10 each independently represent preferably hydrogen, hydroxyl, substituted or unsubstituted straight-chain or branched alkyl having 1 to 6 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 10 carbon atoms, substituted or unsubstituted straight-chain or branched alkenyl having 2 to 6 carbon atoms, substituted or unsubstituted straight-chain or branched alkoxy having 1 to 6 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, or substituted or unsubstituted heteroaryl having 2 to 30 carbon atoms.

As substituents of the alkyl (straight chain, branched chain, cyclic), alkenyl, and alkoxy groups for R ₉ and R ₁₀ , there are no particular restrictions, and examples include, but are not limited to, halogen groups such as fluorine, chlorine, and bromine; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthoxy; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl groups; mercapto groups; cyano groups; amino groups; ester groups; amide groups, etc. As substituents of the aryl and heteroaryl groups for R ₉ and R ₁₀ , examples include, but are not limited to, halogen groups such as fluorine, chlorine, and bromine; alkyl groups such as methyl, ethyl, and propyl; aryl groups such as phenyl and naphthyl; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthoxy; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl groups; mercapto groups; cyano groups; amino groups; ester groups; amide groups, etc. Here, the heteroatom in the "heteroaryl" includes nitrogen, sulfur, oxygen, boron, and silicon.

In formula (III), m ₃ and m ₄ are each independently selected from integers of 1-2.

In formula (IV), R ₁₁ each independently represents preferably hydrogen, hydroxyl, a substituted or unsubstituted straight-chain or branched alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted straight-chain or branched alkenyl group having 2 to 6 carbon atoms, a substituted or unsubstituted straight-chain or branched alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms.

As substituents of the alkyl (straight chain, branched chain, cyclic), alkenyl, and alkoxy groups for R ₁₁ , there are no particular restrictions, and examples include, but are not limited to, halogen groups such as fluorine, chlorine, and bromine; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthoxy; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl; mercapto; cyano; amino; ester; amide, etc. As substituents of the aryl and heteroaryl groups for R ₁₁ , examples include, but are not limited to, halogen groups such as fluorine, chlorine, and bromine; alkyl groups such as methyl, ethyl, and propyl; aryl groups such as phenyl and naphthyl; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthoxy; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl; mercapto; cyano; amino; ester; amide, etc. Here, the heteroatom in the "heteroaryl" includes nitrogen, sulfur, oxygen, boron, and silicon.

In formula (IV), m ₅ is preferably independently selected from an integer of 1 to 2.

In formula (V), R ₁₂ preferably represents a substituted or unsubstituted linear or branched alkylene group having 1 to 15 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 15 carbon atoms, or a substituted or unsubstituted linear or branched etherene group having 1 to 10 carbon atoms.

There are no particular restrictions on the substituents for the alkylene group (straight chain, branched chain, cyclic) and ether group of _R12 , and examples include, but are not limited to, halogen groups such as fluorine, chlorine, and bromine; alkoxy groups such as methoxy and ethoxy; aryloxy groups such as phenoxy and naphthoxy; alkenyl groups such as vinyl; alkenyloxy groups such as vinyloxy; hydroxyl; mercapto; cyano; amino; ester; amide, and the like.

In formula (V), Z ₁ and Z ₂ each independently represent oxygen, sulfur, or a direct bond.

In formula (III), formula (IV) and formula (V), X ₁ , X ₂ , a and b are the same as in formula (I) and formula (II).

In the present application, in some preferred embodiments, from the viewpoint that polycarbonate can more balancedly take into account higher refractive index, lower dispersion, high heat resistance and lower birefringence and has low cost, relative to the total molar amount of all repeating units of polycarbonate, the content of at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II) is 30 to 60 mol%, more preferably 35 to 65 mol%, and the content of at least one structural unit selected from the structural unit represented by formula (III), the structural unit represented by formula (IV) and the structural unit represented by formula (V) is preferably 40 to 85 mol%, more preferably 35 to 65 mol%.

In the present application, in some preferred embodiments, the weight average molecular weight of the polycarbonate is preferably 10,000 g/mol to 200,000 g/mol, more preferably 20,000 g/mol to 100,000 g/mol. When the molecular weight is higher than the above range, the processing difficulty of the polycarbonate material increases; when the molecular weight is lower than the above range, the heat resistance and mechanical properties tend to be impaired. The weight average molecular weight is measured based on gel permeation chromatography (GPC).

In the present application, in some preferred embodiments, the refractive index of polycarbonate is preferably greater than 1.56. When the refractive index is greater than 1.56, it can better meet the general expectations of the refractive index in the art. In some more preferred embodiments, the refractive index of polycarbonate is more preferably greater than 1.63, and further preferably 1.64 to 1.69. The refractive index of polycarbonate can be obtained by testing according to the ASTM D542 test standard.

In the present application, in some preferred embodiments, the Abbe number of the polycarbonate is preferably greater than 17. When the Abbe number is greater than 17, the dispersion can be further reduced. In some more preferred embodiments, the Abbe number of the polycarbonate is more preferably 17-40, and further preferably 18-26.

In the present application, in some preferred embodiments, the glass transition temperature (Tg) of the polycarbonate is preferably above 135°C, so that the polycarbonate of the present application has further increased heat resistance. In some more preferred embodiments, the glass transition temperature (Tg) of the polycarbonate is further 140-170°C, and further preferably 140-155°C.

In the present application, in some preferred embodiments, the birefringence of polycarbonate under d light (wavelength of 589.3 nm) when the thickness is 1 mm is preferably 50 nm or less, more preferably 40 nm or less. The specific method for measuring the birefringence of polycarbonate is described in the embodiments of the present application.

In the present application, in some preferred embodiments, the transmittance of polycarbonate is preferably above 75%, more preferably above 80%, and further preferably above 85%. The transmittance of polycarbonate can be tested according to ASTM D1003 test standard.

In the present application, in some preferred embodiments, the water absorption rate (24h) of polycarbonate is preferably 0.3% or less, more preferably 0.2% or less, and further preferably 0.15 or less. The transmittance of polycarbonate can be tested according to the ASTM D590 test standard.

<Second Aspect>

The embodiment of the present application also provides a method for preparing polycarbonate, which comprises: subjecting a dihydroxy compound and a carbonate diester compound to transesterification polycondensation under the action of a catalyst to obtain polycarbonate,

The dihydroxy compound includes a dihydroxy compound in which two hydroxyl-containing substituted or unsubstituted aromatic groups are connected by M, wherein M forms a ring structure with a divalent X ₃ and two other substituted or unsubstituted aromatic groups, and the two hydroxyl-containing substituted or unsubstituted aromatic groups are not connected to each other except the M or are connected to each other via X ₄ ;

M represents a carbon atom, a silicon atom, a germanium atom or a tin atom;

_X3 represents an oxy group, a thiol group, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms, or a carbonyl group;

_X4 represents a direct bond, oxygen, sulfur, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms.

The preparation method of the present application can easily obtain polycarbonate that can take into account high refractive index, low dispersion, high heat resistance and low birefringence. The process is simple and convenient for large-scale production.

In some preferred embodiments, the ring structure formed by M, _X3 and two other substituted or unsubstituted aromatic groups is a 6- to 10-membered ring.

In some preferred embodiments, the method for preparing the polycarbonate of the present application preferably comprises subjecting at least one dihydroxy compound selected from the dihydroxy compound represented by formula (1) and the dihydroxy compound represented by formula (2) (hereinafter sometimes referred to as a specific dihydroxy compound) to transesterification polycondensation with a carbonate diester compound under the action of a catalyst to obtain the polycarbonate:

In formula (1) and formula (2), the details of _X1 to _X4 , M, _R1 to _R8 , a, b, p1, p2, _m1 and _m2 are the same as those of formula (I) and formula (II) in the above <First Aspect> and are therefore not described again.

The preparation method of the present application can easily obtain polycarbonate that can take into account high refractive index, low dispersion, high heat resistance and low birefringence. The process is simple and convenient for large-scale production.

In some specific embodiments, at least one dihydroxy compound selected from the monomers represented by formulae (1-1) to (1-16) and (2-1) to (2-12) is preferably used.

In the present application, there is no particular limitation on the usage ratio of the above-mentioned specific dihydroxy compounds in all dihydroxy compounds.

In some preferred embodiments, the amount of the above-mentioned specific dihydroxy compound is preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 30 mol% or more, and particularly preferably 40 mol% or more, relative to the total amount of all dihydroxy compounds.

In other preferred embodiments, the amount of the above-mentioned specific dihydroxy compound, relative to the total amount of all dihydroxy compounds, is preferably 80 mol% or less, more preferably 75 mol% or less, further preferably 70 mol% or less, and particularly preferably 65 mol% or less.

In the present application, there is no particular limitation on the specific types of other dihydroxy compounds that can participate in the polycondensation, and various dihydroxy compounds conventionally known in the art can be used.

In some preferred embodiments, it is preferred that the preparation method of the present application comprises: further subjecting at least one dihydroxy compound selected from the dihydroxy compound represented by formula (3), the dihydroxy compound represented by formula (4), and the dihydroxy compound represented by formula (5) to transesterification polycondensation with a carbonate diester compound:

In formula (3), formula (4) and formula (5), the details of _X1 , _X2 , Y, _Z1 , _Z2 , _R9 , _R10 , _R11 , _R12 , a, b, _m3 , _m4 and _m5 are the same as those of formula (III), formula (IV) and formula (V) in the above <first aspect> and are therefore not described in detail here.

In the present application, there is no particular restriction on the usage ratio of at least one dihydroxy compound selected from the dihydroxy compound represented by formula (3), the dihydroxy compound represented by formula (4), and the dihydroxy compound represented by formula (5) among all dihydroxy compounds.

In some preferred embodiments, from the viewpoint that polycarbonate can more balancedly take into account higher refractive index, lower dispersion, high heat resistance and lower birefringence and has low cost, the amount of the above-mentioned specific dihydroxy compound is preferably 30 to 60 mol%, more preferably 35 to 65 mol%, relative to the total amount of all dihydroxy compounds, and the amount of at least one dihydroxy compound selected from the dihydroxy compound represented by formula (3), the dihydroxy compound represented by formula (4) and the dihydroxy compound represented by formula (5) is preferably 40 to 70 mol%, more preferably 35 to 65 mol%.

In the present application, there is no particular restriction on the carbonic acid diester compounds, and various compounds known in the art can be used. Examples include but are not limited to: diaryl carbonates such as diphenyl carbonate, ditolyl carbonate, and dichlorophenyl carbonate; dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, and dicyclofluorene carbonate, and dialkyl carbonates such as dicyclohexyl carbonate; alkyl aryl esters such as methyl tolyl carbonate, ethyl tolyl carbonate, and the like; carbonates of dihydroxy compounds such as dicarbonates, monocarbonates of dihydroxy compounds, and cyclic carbonates. In some preferred embodiments, from the viewpoint that the preparation method of the present application can be carried out more smoothly, the carbonic acid diester compound is preferably selected from at least one of diphenyl carbonate, ditolyl carbonate, dichlorophenyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and dicyclohexyl carbonate.

In the present application, there is no particular limitation on the catalyst used in the polycondensation reaction, and it can be appropriately selected according to the specific monomer types and the like.

In some preferred embodiments, the catalyst is an alkaline substance or an ionic liquid catalyst. Examples of alkaline substances include but are not limited to: alkali metal compounds such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, etc.; alkaline earth metal compounds such as calcium carbonate, magnesium carbonate, etc.; aliphatic tertiary amines such as trimethylamine, triethylamine, etc.; alicyclic tertiary amines such as N,N'-dimethylcyclohexylamine, N,N'-diethylcyclohexylamine, etc.; aromatic tertiary amines such as N,N'-dimethylaniline, N,N'-diethylaniline, etc.; polyamines such as triethylenediamine, etc.; quaternary ammonium salts such as trimethylbenzylammonium chloride, tetramethylammonium chloride, triethylbenzylammonium chloride, etc.; pyridine; guanine; salts of guanidine, etc. Examples of ionic liquid catalysts include but are not limited to: 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), etc.

In some more preferred embodiments, the catalyst is preferably at least one selected from triethylamine, tri-n-butylamine, N,N-dimethylaniline, triethylenediamine, triisopropylamine, tetrabutylammonium fluoride (TBAF), tetrabutylammonium chloride (TBAC), tetrabutylammonium bromide (TBAB), tetrabutylammonium iodide (TBAI), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), pyridine, sodium hydroxide, lithium hydroxide, cesium carbonate, potassium carbonate, potassium bicarbonate, sodium carbonate, lithium carbonate, calcium carbonate and magnesium carbonate.

In the present application, there is no particular limitation on the method for implementing the transesterification polycondensation, and various methods known in the art may be used, such as interfacial polycondensation, solution polycondensation, melt polycondensation, etc. In some preferred embodiments, the transesterification polycondensation is preferably performed by melt polycondensation.

In the present application, there is no particular restriction on the polymerization conditions of the melt polycondensation, which can be appropriately adjusted according to actual needs. In some specific embodiments, the polycondensation temperature is usually 100 to 320°C; the polycondensation time is usually 10 minutes to 6 hours; the polycondensation pressure is usually reduced pressure or normal pressure. In other specific embodiments, the atmosphere of the polycondensation reaction is preferably an inert gas atmosphere, such as a nitrogen atmosphere, a helium atmosphere, etc. In other specific embodiments, the melt polycondensation reaction can be carried out while removing by-products.

In the present application, in the melt polycondensation, all carbonic acid diester compounds and all dihydroxy compounds can be mixed together, or they can be mixed by any method in a batch or continuous manner. When the batch method is used, the order of mixing the components is arbitrary, and an appropriate order can be set arbitrarily.

In the present application, the melt polycondensation may be performed in a single stage or in multiple stages.

In addition, in some specific embodiments, a catalyst deactivator may be used as needed in the melt polycondensation. As the catalyst deactivator, any compound that neutralizes the transesterification catalyst may be used, for example, a sulfur-containing acidic compound and its derivatives.

In the present application, there is no particular restriction on the feeding ratio of various dihydroxy compounds and carbonic acid diester compounds. In some preferred embodiments, from the viewpoint that the preparation method of the present application can be easily prepared while being highly environmentally friendly and having lower production costs, the amount of the carbonic acid diester compound is 0.97 to 1.2 moles relative to 1 mole of the total amount of all dihydroxy compounds.

<Third Aspect>

An embodiment of the present application also provides a resin composition, comprising the above-mentioned polycarbonate of the present application, that is, the polycarbonate described in <First Aspect> or the polycarbonate obtained by the manufacturing method described in <Second Aspect>.

In the present application, the resin composition may also optionally include additives, examples of which include but are not limited to: antioxidants, plasticizers, anti-aging agents, heat stabilizers, fillers, dyes, light stabilizers, ultraviolet absorbers, flame retardants, antistatic agents, release agents, antibacterial agents. These additives may be used alone or in any combination of two or more. The amount of the additive may be added in appropriate amounts as required.

In the present application, the resin composition may also optionally include other polymers, which may be other optical resins different from the embodiments of the present application. The other optical resins may specifically be other polycarbonates different from the embodiments of the present application, or non-polycarbonate optical resins. The content of other optical resins may be added in appropriate amounts as needed.

In the present application, in some specific embodiments, relative to the total mass of the resin composition, the content of the above-mentioned polycarbonate in the present application is preferably 60 mass% or more, more preferably 70 mass% or more, further preferably 80% or more, and particularly preferably 90% or more.

<Fourth Aspect>

The embodiment of the present application also provides an optical product, which includes the above-mentioned polycarbonate of the present application, that is, the polycarbonate described in <First Aspect> or the polycarbonate obtained by the manufacturing method described in <Second Aspect>. In some specific embodiments, the optical product of the present application is preferably made of the above-mentioned resin composition of the present application. In other specific embodiments, the optical product of the present application is preferably made only of the above-mentioned resin composition of the present application.

There is no particular limitation on the molding method of the optical product of the present application, and the polycarbonate or the resin composition can be processed into an optical product by various known molding methods. The optical product can be partially processed with the polycarbonate or the resin composition, or the entire optical product can be processed with the polycarbonate or the resin composition.

In the present application, examples of optical products include but are not limited to: optical lenses, optical films, optical disks, light guide plates or display panels.

Specific examples of optical lenses include, but are not limited to, eyeglass lenses, camera lenses, sensor lenses, lighting lenses, imaging lenses, etc. Among them, specific examples of eyeglass lenses include, but are not limited to, myopia glasses lenses, reading glasses lenses, sunglass lenses, contact lens correction lenses, goggles lenses, etc.; specific examples of camera lenses include, but are not limited to, mobile phone camera lenses, laptop computer camera lenses, desktop camera lenses, car camera lenses, etc.; specific examples of sensor lenses include, but are not limited to, motion detector lenses, proximity sensor lenses, gesture control lenses, infrared sensor lenses, etc.; specific examples of lighting lenses include, but are not limited to, indoor lighting lenses, outdoor lighting lenses, vehicle headlight lenses, vehicle fog light lenses, vehicle rear light lenses, vehicle running light lenses, vehicle fog light lenses, vehicle interior lenses, light emitting diode (LED) lenses or organic light emitting diode (OLED) lenses, etc.; specific examples of imaging lenses include, but are not limited to, scanner lenses, projector lenses, telescope lenses, microscope lenses, magnifying glass lenses, etc.

Specific examples of optical films include but are not limited to light guide films, reflective films, anti-reflection films, diffusion films, filter films, polarizing films, spectroscopic films, and phase films, etc. Optical films can be used in display fields, lighting fields, etc., for example, films for liquid crystal substrates.

<Fifth Aspect>

The present application also provides a device, including the above optical product of the present application. Examples of the device include but are not limited to mobile terminals, glasses, cameras, vehicles (such as cars, motorcycles, trains, etc.), lighting equipment (such as table lamps, ceiling lamps, street lamps, etc.), imaging equipment (such as microscopes, telescopes, projectors, scanners, etc.), etc. Among them, the mobile terminal can specifically include various handheld devices with wireless communication functions (such as mobile phones, tablet computers, mobile notebooks, netbooks, etc.), wearable devices (such as smart watches, etc.), or other processing devices connected to wireless modems, as well as various forms of user equipment (UE), mobile stations (MS), terminal devices, etc.

In some preferred embodiments, the device includes a device body and a camera module mounted on the device body, and the camera module includes a lens as the above-mentioned optical product of the present application. In some more specific embodiments, the device is a mobile terminal, and the mobile terminal includes a camera module, and the camera module includes a camera lens as the above-mentioned optical product of the present application. In some other specific embodiments, the device is a vehicle, and the vehicle includes a camera module, and the camera module includes a camera lens as the above-mentioned optical product of the present application.

<Example>

The embodiments of the present application are described in more detail below, but the present application is not limited to the following embodiments.

The measurement method of each parameter is described below.

(Refractive Index)

In the present application, the refractive index of polycarbonate can be obtained by testing according to the ASTM D542 test standard. Specifically, the refractive index of the polymer is tested by an Abbe refractometer, model DR-M2, and the test wavelength is D light (wavelength is 589.3nm).

(Abbe number)

In the present application, the Abbe number of polycarbonate is calculated by measuring the refractive index of the polymer at different wavelengths (D light, wavelength is 589.3 nm; F light, wavelength is 486.1 nm, C light, wavelength is 656.3) and then by v _d =(n _D -1)/(n _F -n _C ).

(Glass transition temperature Tg)

In the present application, the glass transition temperature of polycarbonate is tested by DSC measuring instrument (model: DSC 214Polyma) in the temperature range of 40-200°C at a rate of 10°C/min, and the inflection point is selected as the glass transition temperature (Tg) of the polymer.

(Birefringence)

In this application, the birefringence of the polycarbonate material is tested by a stress birefringence instrument (model WYL-4), the test light is d light (wavelength 589.3nm), the test range is a circle with a diameter of 1mm at the center of the injection molded part (diameter 10mm, thickness 1mm), and the maximum value is selected as the birefringence of the material.

(Transmittance)

In the present application, the transmittance of polycarbonate can be tested according to the ASTM D1003 test standard.

(Water absorption (24h))

In this application, the 24h water absorption rate is tested by the weight method. The dried injection molded part (60*60*2mm) is immersed in water at 23°C for 24 hours. The masses before and after immersion are weighed as _w1 and _w2 respectively. The water absorption rate is calculated by ( _w2 - _w1 )/ _w1 .

(Weight average molecular weight)

In this application, the weight-average molecular weight was tested by gel permeation chromatography (Shimadzu), the mobile phase was a dimethylformamide (DMF) solution of LiBr with a solubility of 0.01 mol/L, the mobile phase flow rate was 1 mL/min, and polystyrene (PS) was selected as the standard.

Example 1

Under nitrogen atmosphere, 0.1mol optical monomer 1 (structure as follows), 0.1mol diphenyl carbonate (optical monomer 1: diphenyl carbonate = 1:1, molar ratio) were added to a 250mL three-necked glass flask equipped with mechanical stirring, heated to 150°C, and 5× ^10-4 mol of sodium bicarbonate were added, and the ester exchange reaction was carried out under normal pressure for 0.5h to synthesize the prepolymer; then the reaction temperature was slowly increased to 240°C, the vacuum degree was slowly increased to 100Pa, and the reaction was continued for 0.5h to finally obtain polycarbonate with a weight average molecular weight of 38kg/mol. The prepared polymer had a transmittance of 89%, a refractive index of 1.635, an Abbe number of 24.5, a birefringence of 30nm, a glass transition temperature Tg of 143°C, and a 24h water absorption of 0.10%.

Example 2

In a nitrogen atmosphere, 0.1 mol of optical monomer 2 (structure as follows) and 0.1 mol of diphenyl carbonate (optical monomer 2: diphenyl carbonate = 1:1, molar ratio) were added to a 250 mL three-necked glass flask equipped with a mechanical stirrer, heated to 150°C, and 5×10 ^-4 mol of sodium bicarbonate were added. The ester exchange reaction was carried out under normal pressure for 0.5 h to synthesize the prepolymer; then the reaction temperature was slowly increased to 240°C, the vacuum degree was slowly increased to 100 Pa, and the reaction was continued for 0.5 h to finally obtain polycarbonate with a weight average molecular weight of 42 kg/mol. The prepared polymer had a transmittance of 88%, a refractive index of 1.656, an Abbe number of 22, a birefringence of 45 nm, a glass transition temperature Tg of 147°C, and a 24 h water absorption of 0.11%.

Example 3

Under nitrogen atmosphere, 0.1mol optical monomer 3 (structure as follows), 0.1mol diphenyl carbonate (optical monomer 3: diphenyl carbonate = 1:1, molar ratio) were added to a 250mL three-necked glass flask equipped with mechanical stirring, heated to 150°C, and 5× ^10-4 mol of sodium bicarbonate were added, and the ester exchange reaction was carried out under normal pressure for 0.5h to synthesize the prepolymer; then the reaction temperature was slowly increased to 240°C, the vacuum degree was slowly increased to 100Pa, and the reaction was continued for 0.5h to finally obtain polycarbonate with a weight average molecular weight of 37kg/mol. The prepared polymer had a transmittance of 88%, a refractive index of 1.685, an Abbe number of 19, a birefringence of 50nm, a glass transition temperature Tg of 180°C, and a 24h water absorption of 0.08%.

Example 4

Under nitrogen atmosphere, 0.1 mol of optical monomer 4 (structure as follows) and 0.1 mol of diphenyl carbonate (optical monomer 4: diphenyl carbonate = 1:1, molar ratio) were added to a 250 mL three-necked glass flask equipped with mechanical stirring, heated to 150°C, and 5×10 ^-4 mol of sodium bicarbonate were added. The ester exchange reaction was carried out under normal pressure for 0.5 h to synthesize the prepolymer; then the reaction temperature was slowly increased to 240°C, the vacuum degree was slowly increased to 100 Pa, and the reaction was continued for 0.5 h to finally obtain polycarbonate with a weight average molecular weight of 41 kg/mol. The prepared polymer had a transmittance of 89%, a refractive index of 1.643, an Abbe number of 19, a birefringence of 40 nm, a glass transition temperature Tg of 147°C, and a 24 h water absorption of 0.11%.

Example 5

Under nitrogen atmosphere, 0.05mol optical monomer 2, 0.05mol 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF), 0.1mol diphenyl carbonate (optical monomer 2: BPEF: diphenyl carbonate = 0.5:0.5:1, molar ratio) were added to a 250mL three-necked glass flask equipped with mechanical stirring, heated to 150°C, and 5×10-4mol sodium bicarbonate was added. The ester exchange reaction was carried out under normal pressure for 0.5h to synthesize the prepolymer; then the reaction temperature was slowly increased to 240°C, the vacuum degree was slowly increased to 100Pa, and the reaction was continued for 0.5h to finally obtain polycarbonate with a weight average molecular weight of 44kg/mol. The prepared polymer had a transmittance of 89%, a refractive index of 1.648, an Abbe number of 23, a birefringence of 48nm, a glass transition temperature Tg of 146°C, and a 24h water absorption of 0.10%.

Comparative Example 1

Under nitrogen atmosphere, 0.1mol of optical monomer 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF, structure as follows), 0.1mol of diphenyl carbonate (BPEF: diphenyl carbonate = 1:1, molar ratio) were added to a 250mL three-necked glass flask equipped with mechanical stirring, heated to 150℃, and 5× ^10-4mol of sodium bicarbonate were added. The ester exchange reaction was carried out under normal pressure for 0.5h to synthesize the prepolymer; then the reaction temperature was slowly increased to 240℃, the vacuum degree was slowly increased to 100Pa, and the reaction was continued for 0.5h to finally obtain polycarbonate. The prepared polymer has a transmittance of 88%, a refractive index of 1.639, an Abbe number of 22.5, a birefringence of 65nm, a glass transition temperature Tg of 146℃, and a 24h water absorption of 0.09%.

Claims (24)

1. A polycarbonate, characterized in that the polycarbonate contains a carbonate group, and the dihydroxy compound forming the carbonate group includes a dihydroxy compound in which two hydroxyl-containing substituted or unsubstituted aromatic groups are connected by M, wherein M forms a ring structure with a divalent _X3 and two other substituted or unsubstituted aromatic groups, and the two hydroxyl-containing substituted or unsubstituted aromatic groups are not connected to each other except the M or are connected to each other via _X4 ; M represents a carbon atom, a silicon atom, a germanium atom or a tin atom; X ₃ represents a thiol group; _X4 represents a direct bond, oxygen, sulfur, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms. 2. The polycarbonate according to claim 1, characterized in that the polycarbonate comprises at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II): In formula (I) and formula (II), X ₁ and X ₂ each independently represent a substituted or unsubstituted linear or branched alkylene group having 1 to 8 carbon atoms; X ₃ , X ₄ , and M are the same as above; R ₁ and R ₂ each independently represent hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, hydroxy, ester, cyano, amino, thiol, or an atom or atomic group that can replace the above groups; R ₃ to R ₈ each independently represent hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, hydroxyl, ester, cyano, amino, thiol, or an atom or atomic group that can replace the above groups, and at least two adjacent substituents in R ₃ to R ₈ can be connected to each other to form a ring structure; a and b are each independently selected from integers of 0 to 5; p1 and p2 are each independently selected from integers of 1 to 3; m ₁ and m ₂ are each independently selected from integers of 1-4. 3. The polycarbonate according to claim 2, characterized in that the content of at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II) is 10 mol% or more relative to the total molar amount of all repeating units of the polycarbonate. 4. The polycarbonate according to claim 3 is characterized in that the content of at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II) is less than 80 mol% relative to the total molar amount of all repeating units of the polycarbonate. 5. The polycarbonate according to claim 1 or 2, characterized in that the polycarbonate further comprises at least one structural unit selected from the group consisting of a structural unit represented by formula (III), a structural unit represented by formula (IV), and a structural unit represented by formula (V): In formula (III), formula (IV) and formula (V), X ₁ , X ₂ , a, and b are the same as those in formula (I) and formula (II); Y represents oxygen, sulfur, a sulfoxide group, a sulfone group, a substituted or unsubstituted linear or branched alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 20 carbon atoms, a substituted or unsubstituted fluorenylene group, a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 carbon atoms; _R9 , _R10 , and _R11 each independently represent hydrogen, hydroxyl, substituted or unsubstituted linear or branched alkyl having 1 to 6 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 10 carbon atoms, substituted or unsubstituted linear or branched alkenyl having 2 to 6 carbon atoms, substituted or unsubstituted linear or branched alkoxy having 1 to 6 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, or substituted or unsubstituted heteroaryl having 2 to 30 carbon atoms; _R12 represents a substituted or unsubstituted linear or branched alkylene group having 1 to 15 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 15 carbon atoms, or a substituted or unsubstituted linear or branched ether group having 1 to 10 carbon atoms; Z ₁ and Z ₂ each independently represent oxygen, sulfur, or a direct bond; m ₃ , m ₄ , and m ₅ are each independently selected from integers of 1-2. 6. The polycarbonate according to claim 5 is characterized in that, relative to the total molar amount of all repeating units of the polycarbonate, the content of at least one structural unit selected from the structural unit represented by formula (I) and the structural unit represented by formula (II) is 30 to 60 mol%, and the content of at least one structural unit selected from the structural unit represented by formula (III), the structural unit represented by formula (IV), and the structural unit represented by formula (V) is 40 to 85 mol%. 7 . The polycarbonate according to claim 1 , wherein the weight average molecular weight of the polycarbonate is 10,000 g/mol to 200,000 g/mol. 8. The polycarbonate according to claim 1 or 2, characterized in that the refractive index of the polycarbonate is greater than 1.56. 9 . The polycarbonate according to claim 1 , wherein the polycarbonate has an Abbe number of 17 or more. 10 . The polycarbonate according to claim 1 or 2 , wherein the polycarbonate has a glass transition temperature of 135° C. or higher. 11 . The polycarbonate according to claim 1 or 2 , wherein the birefringence of the polycarbonate under d-light is 50 nm or less when the thickness is 1 mm. 12. A method for preparing polycarbonate, comprising: subjecting a dihydroxy compound and a carbonic acid diester compound to transesterification polycondensation under the action of a catalyst to obtain polycarbonate, The dihydroxy compound includes a dihydroxy compound in which two hydroxyl-containing substituted or unsubstituted aromatic groups are connected by M, wherein M forms a ring structure with a divalent X ₃ and two other substituted or unsubstituted aromatic groups, and the two hydroxyl-containing substituted or unsubstituted aromatic groups are not connected to each other except the M or are connected to each other via X ₄ ; M represents a carbon atom, a silicon atom, a germanium atom or a tin atom; X ₃ represents a thiol group; _X4 represents a direct bond, oxygen, sulfur, a disulfide group, a sulfoxide group, a sulfone group, a substituted or unsubstituted imino group, a substituted or unsubstituted silylene group having 1 to 3 silicon atoms, a substituted or unsubstituted phosphorous group, a substituted or unsubstituted linear or branched alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms. 13. The preparation method according to claim 12, characterized in that it comprises: subjecting at least one dihydroxy compound selected from the dihydroxy compound represented by formula (1) and the dihydroxy compound represented by formula (2) to transesterification polycondensation with a carbonate diester compound under the action of a catalyst to obtain a polycarbonate: In formula (1) and formula (2), X ₁ and X ₂ each independently represent a substituted or unsubstituted linear or branched alkylene group having 1 to 8 carbon atoms; X ₃ , X ₄ , and M are the same as above; R ₁ and R ₂ each independently represent hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, hydroxy, ester, cyano, amino, thiol, or an atom or atomic group that can replace the above groups; R ₃ to R ₈ each independently represent hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, hydroxyl, ester, cyano, amino, thiol, or an atom or atomic group that can replace the above groups, and at least two adjacent substituents in R ₃ to R ₈ can be connected to each other to form a ring structure; a and b are each independently selected from integers of 0 to 5; p1 and p2 are each independently selected from integers of 1 to 3; m ₁ and m ₂ are each independently selected from integers of 1-4. 14. The preparation method according to claim 12 or 13, characterized in that it comprises: further subjecting at least one dihydroxy compound selected from the group consisting of the dihydroxy compound represented by formula (3), the dihydroxy compound represented by formula (4), and the dihydroxy compound represented by formula (5) to transesterification polycondensation with a carbonic acid diester compound: In formula (3), formula (4) and formula (5), X ₁ , X ₂ , a, and b are the same as those in formula (1) and formula (2); Y represents oxygen, sulfur, a sulfoxide group, a sulfone group, a substituted or unsubstituted linear or branched alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 20 carbon atoms, a substituted or unsubstituted fluorenylene group, a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 carbon atoms; _R9 , _R10 , and _R11 each independently represent hydrogen, hydroxyl, substituted or unsubstituted linear or branched alkyl having 1 to 6 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 10 carbon atoms, substituted or unsubstituted linear or branched alkenyl having 2 to 6 carbon atoms, substituted or unsubstituted linear or branched alkoxy having 1 to 6 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, or substituted or unsubstituted heteroaryl having 2 to 30 carbon atoms; _R12 represents a substituted or unsubstituted linear or branched alkylene group having 1 to 15 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 15 carbon atoms, or a substituted or unsubstituted linear or branched ether group having 1 to 10 carbon atoms; Z ₁ and Z ₂ each independently represent oxygen, sulfur, or a direct bond; m ₃ , m ₄ , and m ₅ are each independently selected from integers of 1-2. 15. The preparation method according to claim 12 or 13, characterized in that the carbonic acid diester compound is at least one selected from diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate and dicyclohexyl carbonate. 16. The preparation method according to claim 12 or 13, characterized in that the catalyst is an alkaline substance or an ionic liquid catalyst. 17. The preparation method according to claim 12 or 13, characterized in that the transesterification polycondensation is transesterification melt polycondensation. 18. The preparation method according to claim 12 or 13, characterized in that the amount of the carbonic acid diester compound is 0.97 to 1.2 moles relative to 1 mole of the total amount of all dihydroxy compounds. 19. A resin composition, characterized in that the resin composition comprises the polycarbonate according to any one of claims 1 to 11 or the polycarbonate prepared by the preparation method according to any one of claims 12 to 18. 20. An optical product, characterized in that the optical product comprises the polycarbonate according to any one of claims 1 to 11 or the polycarbonate prepared by the preparation method according to any one of claims 12 to 18. 21. The optical product according to claim 20, characterized in that the optical product comprises an optical lens, an optical film, an optical disc, a light guide plate or a display panel. 22. The optical product according to claim 21, wherein the optical lens comprises a spectacle lens, a camera lens, a sensor lens, a lighting lens, or an imaging lens. 23. A device, characterized in that it comprises the optical product according to any one of claims 20 to 22. 24. The device according to claim 23 is characterized in that the device comprises a device body and a camera module assembled on the device body, and the camera module comprises a lens as the optical product.