An aromatic polycarbonate resin, a preparation method thereof and an application thereof

Abstract

The present invention discloses an aromatic polycarbonate resin, a preparation method thereof and an application thereof, belonging to the technical field of optical resins. It solves the technical problem that the comprehensive properties such as the glass transition temperature and refractive index of polycarbonate in the prior art need to be improved when used as an optical material. The polycarbonate of the present invention comprises repeating units of formula (I) and formula (II). The preparation method of the polycarbonate resin of the present invention includes reacting a dihydroxy compound in formula (a) and formula (b) with a carbonic acid diester compound under the action of a catalyst by means of melt transesterification polycondensation. By introducing a benzene ring and a sulfur element and controlling the position of the benzene ring substituents introduced, the present invention improves the refractive index while increasing the molecular weight and lowering the glass transition temperature, so that the polycarbonate has good comprehensive properties as an optical material.

Description

Technical Field

[0001] The present invention belongs to the technical field of polycarbonate resins, and particularly relates to an aromatic polycarbonate resin, a preparation method thereof, and an application thereof. Background Art

[0002] As a traditional lens material, optical glass has excellent optical properties, dimensional stability, and heat resistance. However, the production cost of optical glass is high, its processability is poor, and the yield is low when used in the manufacture of precision components. Due to its excellent optical properties, polycarbonate resin has been widely used in mobile phone lenses, vehicle-mounted lenses, security lenses, AR / VR and other fields. Polycarbonate resin has the advantages of strong plasticity and low density. When processed into optical components of various portable precision devices, it has better designability and lightweight characteristics, and is gradually replacing optical glass and being more widely used.

[0003] The refractive index of traditional polycarbonate is relatively low and cannot meet the requirements of optical applications. In recent years, through research, domestic and foreign scholars have found that polymers rich in benzene rings, halogen (except F) and other groups have a high refractive index. However, halogens are easily detached and have a greater impact on the environment. Therefore, the existing technical means mainly use monomers rich in benzene rings to polymerize to obtain polycarbonate with a high refractive index. Patent CN115461388B copolymerizes 10,10'-bis(2-hydroxyethoxy)-9,9'-biphenanthrene and 9,9'-bis(4-(2-hydroxyethoxy)phenyl)fluorene (BPEF) in a molar ratio of 1:1 to obtain a polycarbonate with a refractive index of 1.676, an Abbe number of 19, and a glass transition temperature of 154°C. However, with the increase in the number of benzene rings, to a certain extent, the molecular weight of the polymer decreases, and the refractive index of the obtained polycarbonate is not high enough.

[0004] Patent CN112175178B introduces the monomer 2,2'-bis(2-hydroxyethoxy)-6,6'-bis(naphthalen-2-yl)-1,1'-dithionaphthalene to copolymerize with BPEF to obtain a polycarbonate with a refractive index as high as 1.725, a glass transition temperature of 176°C, and a weight average molecular weight of only 13,200. The low molecular weight is due to the too strong rigidity of the molecular chain segments, the weak activity of the chain segments in the reaction, and a large steric hindrance effect, which reduces the polymerization reaction activity. Although the molecular weight is low, the introduction of sulfur elements into the structure rich in benzene rings also has a certain promoting effect on the refractive index. In addition, the high glass transition temperature and the low molecular weight may lead to a decrease in the thermal stability of the material, and it is easy to degrade during the processing and molding process.

[0005] Based on the research of the above-mentioned existing technologies and the understanding of well-known technologies, reducing the glass transition temperature to a certain extent, increasing the processing temperature range, and reducing the influence on the refractive index by copolymerization have important guiding significance for the preparation of high refractive index polycarbonate materials. Therefore, developing polycarbonate resin materials with both high refractive index and high molecular weight to meet the application requirements in high-precision optical instruments is the key research direction in the field of optical polycarbonates. Summary of the Invention

[0006] Aiming at the technical problems that the comprehensive properties such as glass transition temperature and refractive index of polycarbonate are not high when used as an optical material in the prior art, an aromatic polycarbonate resin, a preparation method thereof, and an application thereof are provided.

[0007] The technical solution adopted in the present invention is as follows:

[0008] An aromatic polycarbonate resin contains repeating units represented by the following formula (I) and formula (II).

[0009]

[0010] Wherein, based on the total molar amount of the structural units being 100%, the molar content of the structural units represented by formula (I) is 10% - 100%.

[0011] In the preferred aromatic polycarbonate resin of the present invention, based on the total amount of the structural units being 100%, the sum of the molar ratio of the structural units represented by formula (I) and the molar ratio of the structural units represented by formula (II) is 100%, and the molar ratio of the structural units represented by formula (I) and the structural units represented by formula (II) in the polycarbonate resin is (1:9) - (9:1).

[0012] In the preferred aromatic polycarbonate resin of the present invention, the molar ratio of the structural units represented by formula (I) and the structural units represented by formula (II) in the polycarbonate resin is (1:1) - (9:1).

[0013] In the preferred aromatic polycarbonate resin of the present invention, the molar ratio of the structural units represented by formula (I) and the structural units represented by formula (II) in the polycarbonate resin is (7:3) - (9:1).

[0014] The content of the structural units can be detected by conventional methods in the art or calculated according to the feed amount. In the present invention, it is calculated according to the feed amount.

[0015] In the preferred aromatic polycarbonate resin of the present invention, the weight average molecular weight of the polycarbonate is 20,000 - 100,000.

[0016] Preferably, it is 30,000 - 60,000.

[0017] It is further preferably 35,000 - 50,000.

[0018] A method for preparing an aromatic polycarbonate resin, which includes reacting a dihydroxy compound in formula (a) and / or formula (b) with a dicarbonate compound under the action of a catalyst through melt transesterification polycondensation reaction;

[0019]

[0020]

[0021] The dicarbonate compound is selected from at least one of dimethyl carbonate, diphenyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, and dimethylxylene carbonate, and is preferably diphenyl carbonate.

[0022] Preferably, the catalyst is an alkali metal compound or an alkaline earth metal compound.

[0023] In the preferred method for preparing a polycarbonate resin of the present invention, the catalyst is an alkaline earth metal compound, preferably a nano-magnesium oxide catalyst.

[0024] Preferably, the particle size of the nano-magnesium oxide catalyst is 50 nm, and it has a large specific surface area, which can more fully contact with the reaction raw materials to play a catalytic role. In addition, magnesium oxide is insoluble in water and has relatively high melting point and thermal stability, ensuring the full and stable progress of the reaction.

[0025] In the preferred method for preparing a polycarbonate resin of the present invention, the molar ratio of the total amount of the dihydroxy compound in formula (a) and formula (b) to the dicarbonate compound is (0.98 - 1.02):1, preferably (0.98 - 1):1, and more preferably 1:1.

[0026] In the preferred method for preparing a polycarbonate resin of the present invention, the molar ratio of the catalyst to the dicarbonate compound is (0.01 - 0.1):100, preferably (0.01 - 0.05):100.

[0027] In the preferred method for preparing a polycarbonate resin of the present invention, the steps of the reaction include:

[0028] Step 1: Under heating conditions, carry out transesterification reaction under normal pressure or reduced pressure;

[0029] Step 2: Remove the small molecule by-products after the reaction;

[0030] Step 3: Then, under heating and high vacuum, carry out polycondensation reaction to obtain a polycarbonate resin.

[0031] Preferably, the conditions for the transesterification reaction in step 1 are as follows: the temperature is 140 - 240 °C, preferably 160 - 200 °C, the reaction time is 0.5 - 6 hours, preferably 2 - 4 hours; within 0.5 hours thereafter, the pressure is reduced to 100 Torr, and the temperature is raised to 220 °C, and the reaction is carried out for 1 hour.

[0032] Preferably, in step 3, within 0.5 hours after removing the small - molecule by - products, the temperature is raised to 240 °C, and the pressure is gradually reduced to below 1 Torr, and the reaction is carried out under these conditions for 0.5 - 2 hours.

[0033] The preferred method for preparing the polycarbonate resin of the present invention further includes step 4: post - treatment.

[0034] The steps of the post - treatment include: after the reaction is completed, N2 is introduced to return the pressure in the reaction flask to normal pressure. The product is dissolved using a first solvent such as dichloromethane, and after dissolution, it is slowly poured into a beaker containing a second solvent such as absolute ethanol, and stirred to precipitate the product. After washing with ethanol, it is dried under vacuum.

[0035] An application of a polycarbonate resin or a polycarbonate resin prepared by the above - mentioned method in optical materials.

[0036] The glass transition temperature of the polycarbonate material in the present invention is 122 - 165 °C, preferably 135 - 160 °C, more preferably 145 - 160 °C.

[0037] The refractive index nD of the polycarbonate resin in the present invention is 1.652 - 1.745, preferably 1.673 - 1.735, more preferably 1.694 - 1.735.

[0038] The Abbe number v of the polycarbonate resin in the present invention is 18 - 24, preferably 18 - 21, more preferably 19 - 20.

[0039] The light transmittance of the polycarbonate resin in the present invention is 86 - 89%, preferably 86% - 88%, more preferably 87 - 88%.

[0040] The monomer with a dithiophene structure has a relatively large aryl group, which increases the molecular rigidity and has a relatively high glass transition temperature. By introducing the monomer structure of linear TDP containing a benzene ring and sulfur, the molecular rigidity of the copolymer can be reduced, and the glass transition temperature can be lowered within a controllable range; compared with dithiophene, the linear TDP structure has a relatively reducing effect on the refractive index, but the introduction of a small amount of TDP can lower the glass transition temperature without much reduction in the refractive index, facilitating the processing and molding of polymer materials. The Abbe number is related to the dispersion of the material, and the introduction of sulfur can reduce the dispersion. Therefore, when selecting monomers to adjust the glass transition temperature and refractive index, the selection of TDP has certain advantages.

[0041] In addition, in terms of the weight-average molecular weight, due to the position of the benzene ring substituents, which affects the molecular weight, the present invention preferably uses hydroxy-phenanthrene to synthesize the bisthiophenanthrene structure, ensuring a relatively high weight-average molecular weight. Then, in combination with the linear TDP structure, the glass transition temperature is reduced, avoiding processing brittleness while ensuring good fluidity and endowing it with excellent formability.

[0042] The polycarbonate resin provided by the present invention has the advantages of both high refractive index and high molecular weight, meeting the application requirements as an optical resin in the field of optical components.

[0043] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0044] 1. For the polycarbonate resin of the present invention, by introducing a benzene ring and sulfur elements and by adjusting the position of the benzene ring substituents, the refractive index and the molecular weight are increased while the glass transition temperature is decreased, endowing the polycarbonate with good comprehensive properties as an optical material.

[0045] 2. The present invention successfully prepares a polycarbonate resin suitable for optical materials by using special dihydroxy compounds and dicarbonate compounds and conducting synthesis control under the action of a unique nano-magnesium oxide catalyst.

[0046] 3. The present invention uses a self-made dihydroxy compound with a biphenanthrene structure as the raw material for generating the polycarbonate resin, and selects a suitable catalyst, nano-magnesium oxide, and various combinations of preparation parameters to successfully prepare a polycarbonate resin with good comprehensive properties. Detailed Embodiments

[0047] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present application, rather than all of them.

[0048] The raw materials used in the present invention are as follows:

[0049] 9-Hydroxy-phenanthrene was purchased from Zhengzhou Alpha Chemical Co., Ltd.; 10,10'-Dihydroxy-9,9'-biphenanthrene was purchased from Shanghai Huifu Biopharmaceutical Technology Co., Ltd.; 4,4'-Dihydroxydiphenyl sulfide was purchased from Shanghai Macklin Biochemical Co., Ltd.; Diphenyl carbonate was purchased from Ningbo Zhejiang Iron Dafeng Chemical Co., Ltd. 10,10'-Bis(2-hydroxyethoxy)-9,9'-biphenanthrene and 10,10'-Bis(2-hydroxyethoxy)-9,9'-bisthiophenanthrene were synthesized in-house.

[0050] 1. Preparation of 10,10'-Bis(2-hydroxyethoxy)-9,9'-biphenanthrene

[0051] The synthesis route is as follows:

[0052]

[0053] Add 0.1 mol of 10,10'-dihydroxy-9,9'-biphenanthrene and 0.3 mol of ethylene carbonate into a reaction flask, add 1.4 g of potassium carbonate as a catalyst, 100 ml of xylene, and 30 ml of N,N-dimethylformamide (abbreviated as DMF) as reaction solvents. The reaction temperature is 130 °C. After heating under reflux for 2 h, the content of 10,10'-dihydroxy-9,9'-biphenanthrene analyzed by HPLC is less than 0.1% (its conversion rate reaches 99.9%), and the reaction is stopped. Cool down to 50 °C, add deionized water, stir for 30 min, let it stand for liquid separation, collect the xylene phase, then perform hot filtration, collect the filtrate, stir and cool for crystallization to obtain 10,10'-bis(2-hydroxyethoxy)-9,9'-biphenanthrene.

[0054] The NMR results of the target product 10,10'-bis(2-hydroxyethoxy)-9,9'-biphenanthrene are as follows: 1H-NMR (300 MHz, DMSO) δ×10 -6 : 9.08 (dd, 2H), 8.98 (dd, 2H), 8.17 (dd, 2H), 8.11 (dd, 2H), 7.70 (m, 2H), 7.68 (m, 2H), 7.62 (m, 4H), 4.13 (t, 4H), 3.81 (t, 4H), 1.56 (d, 2H).

[0055] 2. Preparation of 10,10'-bis(2-hydroxyethoxy)-9,9'-bithiophenanthrene

[0056] The synthesis route is as follows:

[0057]

[0058] (1) Add 0.1 mol of 9-hydroxyphenanthrene into a four-necked flask equipped with a mechanical stirrer, thermometer, constant pressure dropping funnel, and condenser reflux tube. At the same time, add 50 ml of a mixed solution of toluene and ethyl acetate with a mass ratio of 2:3, and stir to dissolve it. Control the system temperature at 15 °C, then slowly dropwise add 0.05 mol of sulfur dichloride. After the addition, maintain the reaction at 15 °C for 3 h, then raise the temperature to 120 °C, concentrate the reaction solution to remove most of the solvent, place the reaction solution in a refrigerator (-15 °C) to precipitate a solid, filter the solid, recrystallize and purify it with absolute ethanol, and then filter and dry to obtain 10,10'-dihydroxy-9,9'-bithiophenanthrene;

[0059] (2) Add 0.1 mol of 10,10'-dihydroxy-9,9'-bi(thiophene) and 0.3 mol of ethylene carbonate into a reaction flask, add 1.4 g of potassium carbonate as a catalyst, 100 ml of xylene, and 30 ml of DMF as reaction solvents. The reaction temperature is 130 °C. After heating under reflux for 2 h, analyze the content of 10,10'-dihydroxy-9,9'-bi(thiophene) by HPLC and find that it is less than 0.1% (its conversion rate reaches 99.9%), then stop the reaction. Cool down to 50 °C, add deionized water, stir for 30 min, let it stand for liquid separation, collect the xylene phase, then perform hot filtration, collect the filtrate, stir and cool for crystallization to obtain 10,10'-bis(2-hydroxyethoxy)-9,9'-bi(thiophene).

[0060] The NMR results of the target product 10,10'-bis(2-hydroxyethoxy)-9,9'-bi(thiophene) are as follows: 1H-NMR (300 MHz, DMSO) δ×10 -6 : 8.98 (dd, 4H), 8.11 (dd, 4H), 7.68 (m, 4H), 7.62 (m, 4H), 4.13 (t, 4H), 3.81 (t, 4H), 1.56 (d, 2H).

[0061] Example 1

[0062] An aromatic polycarbonate resin contains repeating units

[0063] The molar ratio of the two is 1:9, and the preparation method is as follows:

[0064] Add 0.003 mol of 10,10'-bis(2-hydroxyethoxy)-9,9'-bi(thiophene) (hereinafter referred to as "BHEBPSN" for short), 0.027 mol of 4,4'-dihydroxydiphenyl sulfide (hereinafter referred to as "TDP" for short), 0.03 mol of diphenyl carbonate (hereinafter referred to as "DPC" for short), and the catalyst nano-magnesium oxide 8×10 -6mol was added to a 50 ml three-necked round-bottom flask. N2 was introduced to displace the air in the system, keeping the reaction flask at atmospheric pressure, and the reaction raw materials were heated under a N2 atmosphere to melt them. The reaction temperature was gradually raised from room temperature to the range of 140 - 160 °C, and the reaction raw materials were completely melted into a colorless transparent liquid. Then the temperature was further raised to 180 °C and maintained for 2 hours. Subsequently, the pressure was slowly reduced to 100 Torr within 0.5 hours, and the temperature was gradually raised to 220 °C, and the reaction continued for 1 hour. Finally, the temperature was raised to 240 °C, and the pressure was reduced to below 1 Torr within 0.5 hours, and the reaction continued for 0.5 hours. After the reaction ended, N2 was introduced to restore the pressure in the reaction flask to atmospheric pressure. After cooling, the product in the reaction flask was dissolved in dichloromethane, and then slowly poured into a beaker containing anhydrous ethanol, and stirred to precipitate the product. After washing with ethanol, it was dried in vacuo at 100 °C for 8 hours to obtain the polycarbonate resin.

[0065] Example 2

[0066] An aromatic polycarbonate resin containing repeating units The molar ratio of the two is 3:7, and the preparation method is as follows:

[0067] The raw material ratio was adjusted to 0.009 mol of BHEBPSN, 0.021 mol of TDP, 0.03 mol of DPC, and 8×10 -6 mol of catalyst nano-magnesium oxide, which was added to a 50 ml three-necked round-bottom flask. N2 was introduced to displace the air in the system, keeping the reaction flask at atmospheric pressure, and the reaction raw materials were heated under a N2 atmosphere to melt them. The subsequent process was the same as that in Example 1.

[0068] Example 3

[0069] An aromatic polycarbonate resin containing repeating units The molar ratio of the two is 5:5, and the preparation method is as follows:

[0070] The raw material ratio was adjusted to 0.015 mol of BHEBPSN, 0.015 mol of TDP, 0.03 mol of DPC, and 8×10 -6 mol of catalyst nano-magnesium oxide, which was added to a 50 ml three-necked round-bottom flask. N2 was introduced to displace the air in the system, keeping the reaction flask at atmospheric pressure, and the reaction raw materials were heated under a N2 atmosphere to melt them. The subsequent process was the same as that in Example 1.

[0071] Example 4

[0072] An aromatic polycarbonate resin containing repeating units The molar ratio is 7:3, and the preparation method is as follows:

[0073] Adjust the raw material ratio to 0.021 mol of BHEBPSN, 0.009 mol of TDP, 0.03 mol of DPC, and 8×10 -6 mol of the catalyst nano-magnesium oxide, and add them to a 50 ml three-necked round-bottom flask. Pass N2 to displace the air in the system, keep the reaction flask at atmospheric pressure, and heat it under a N2 atmosphere to melt the reaction raw materials. The subsequent process is the same as that in Example 1.

[0074] Example 5

[0075] An aromatic polycarbonate resin containing repeating units with a molar ratio of 9:1, and the preparation method is as follows:

[0076] Adjust the raw material ratio to 0.027 mol of BHEBPSN, 0.003 mol of TDP, 0.03 mol of DPC, and 8×10 -6 mol of the catalyst nano-magnesium oxide, and add them to a 50 ml three-necked round-bottom flask. Pass N2 to displace the air in the system, keep the reaction flask at atmospheric pressure, and heat it under a N2 atmosphere to melt the reaction raw materials. The subsequent process is the same as that in Example 1.

[0077] Example 6

[0078] An aromatic polycarbonate resin containing repeating units The preparation method is as follows:

[0079] Add 0.03 mol of BHEBPSN, 0.03 mol of DPC and 8×10 -6 mol of the catalyst nano-magnesium oxide to a 50 ml three-necked round-bottom flask. Pass N2 to displace the air in the system, keep the reaction flask at atmospheric pressure, and heat it under a N2 atmosphere to melt the reaction raw materials. The subsequent process is the same as that in Example 1.

[0080] Comparative Example 1

[0081] An aromatic polycarbonate resin containing repeating units The preparation method is as follows:

[0082] Add 0.03 mol of TDP, 0.03 mol of DPC and 8×10 -6 mol of the catalyst nano-magnesium oxide to a 50 ml three-necked round-bottom flask. Pass N2 to displace the air in the system, keep the reaction flask at atmospheric pressure, and heat it under a N2 atmosphere to melt the reaction raw materials. The subsequent process is the same as that in Example 1.

[0083] Comparative Example 2

[0084] An aromatic polycarbonate resin containing repeating units The molar ratio of the two is 1:1, and the preparation method is as follows:

[0085] 0.015 mol of 10,10'-bis(2-hydroxyethoxy)-9,9'-biphenanthrene (hereinafter referred to as "BHEBPN" for short), 0.015 mol of TDP, 0.03 mol of DPC, and 8×10 -6 mol of nano-magnesium oxide were placed in a 50 ml three-necked round-bottom flask. The air in the system was displaced by passing N2, and the reaction flask was kept at normal pressure and heated under a N2 atmosphere to melt the reaction raw materials. The subsequent process was the same as that in Example 1.

[0086] The methods for preparing samples and testing performance involved in the examples and comparative examples of the present invention are as follows:

[0087] 1. Samples and preparation methods for performance evaluation

[0088] (1) Film

[0089] 5 g of the obtained polycarbonate was dissolved in 40 ml of dichloromethane. After complete dissolution, it was coated on a small film coater. The film thickness was set to 0.02 mm on the coater. At room temperature, after the solvent evaporated, the film sample was taken off and placed for 2 hours to obtain sample (a) for optical property detection.

[0090] (2) Molded sheet

[0091] The molded sheet was prepared by an injection molding method as sample (b). The temperature of the injection molding machine was segmented between 220 - 265 °C, the mold temperature was 120 - 140 °C, and the mold parameters were a sheet thickness of 1 mm, a length of 2 cm, and a width of 1 cm.

[0092] 2. Performance evaluation indicators and testing methods

[0093] (1) Glass transition temperature (Tg)

[0094] The prepared aromatic polycarbonate was subjected to DSC measurement using a TA DSC 2920 instrument in a nitrogen atmosphere (50 mL / min) at a temperature change rate of 10 °C / min.

[0095] (2) Weight-average molecular weight (Mw)

[0096] The weight-average molecular weight (Mw) of the prepared aromatic polycarbonate was measured at 35 °C using a Waters 1515 pump and a 2414 refractive index detector with two chromatographic columns (PLgel 5 mm Mixed-C 300 - 7.5 mm). Chloroform was used as the eluent at a flow rate of 1 mL / min, and polystyrene standards were used for calibration.

[0097] (3) Refractive index (nD)

[0098] The refractive index of sample (b) was measured at room temperature at a wavelength of 589 nm on an Abbe refractometer (WYA(2WAJ)).

[0099] (4) Abbe number (v)

[0100] According to the measurement method of refractive index in (3), the refractive indices nC, nD and nF at wavelengths of 486 nm, 589 nm and 656 nm were measured at room temperature respectively, and the Abbe number was calculated using the formula v = (nD - 1) / (nF - nC).

[0101] (5) Transmittance

[0102] The transmittance of sample (a) was tested using a transmittance / haze meter ( -810) for the test.

[0103] The experimental results of the polymer samples prepared in the examples and comparative examples of the present invention are listed in Table 1.

[0104] Table 1. Parameters and performance test data of examples and comparative examples

[0105]

[0106] As can be seen from Table 1:

[0107] 1. In Examples 1-6 of the present invention, the refractive index of polycarbonate increases with the increase of the molar content of BHEBPSN, and the glass transition temperature also rises with the increase of the molar content of BHEBPSN, but the molecular weight gradually decreases. This may be due to the relatively large molecular volume of BHEBPSN, resulting in a certain reduction in polymerization activity and a decrease in the number of linking units, thus leading to a decrease in molecular weight.

[0108] 2. As can be seen from Example 6, when only BHEBPSN is contained, the refractive index of the prepared polycarbonate is higher, but its molecular weight is slightly lower, the weight-average molecular weight just exceeds 30,000, and the transmittance is also relatively slightly lower. Generally speaking, the comprehensive performance of Examples 3-5 is better, especially Example 5.

[0109] 3. As can be seen from Example 3 and Comparative Example 2, when BHEBPSN is replaced with BHEBPN, its weight-average molecular weight, glass transition temperature and transmittance are basically unchanged. From the perspective of refractive index, the polycarbonate with BHEBPSN structure is higher than that with BHEBPN structure, indicating that the present invention further improves the refractive index by introducing sulfur into the binaphthyl structure on the premise of ensuring almost no change in molecular weight, glass transition temperature and transmittance.

[0110] As can be seen from the above results, the present invention coordinates in multiple aspects such as the number of benzene rings, substitution positions, and introduction of sulfur, and obtains a polycarbonate resin with high comprehensive properties in terms of weight-average molecular weight, glass transition temperature, refractive index, Abbe number, and light transmittance, which can be applied in the optical field.

[0111] The above-described embodiments merely represent the specific implementation manners of the present application, and the description thereof is relatively specific and detailed. However, it should not be construed as a limitation to the protection scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the technical solution of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application.

Claims

1. An aromatic polycarbonate resin, characterized in that, containing repeating units represented by the following formula (I) and formula (II), （I） (II) wherein, based on the total molar amount of the structural units represented by formula (I) and formula (II) being 100%, the molar content of the structural units represented by formula (I) is 10% - 100%.

2. The polycarbonate resin according to claim 1, wherein: In the polycarbonate resin, the molar ratio of the structural units represented by formula (I) to the structural units represented by formula (II) is (1:9) - (9:1).

3. The polycarbonate resin according to claim 1, wherein: In the polycarbonate resin, the molar ratio of the structural units represented by formula (I) to the structural units represented by formula (II) is (1:1) - (9:1).

4. The polycarbonate resin according to claim 1, wherein: In the polycarbonate resin, the molar ratio of the structural units represented by formula (I) to the structural units represented by formula (II) is (7:3) - (9:1).

5. The polycarbonate resin according to any one of claims 1 to 4, characterized in that: The polycarbonate has a weight-average molecular weight of 30,000 - 60,000.

6. A method for preparing a polycarbonate resin according to any one of claims 1 - 5, comprising reacting a dihydroxy compound in formula (a) with a carbonic acid diester compound under the action of a catalyst by melt transesterification polycondensation reaction, or reacting a dihydroxy compound in formula (a) and formula (b) with a carbonic acid diester compound under the action of a catalyst by melt transesterification polycondensation reaction; （a） （b） The carbonic acid diester compound is selected from at least one of dimethyl carbonate, diphenyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, and dimethylxylene carbonate; the catalyst is an alkali metal compound or an alkaline earth metal compound.

7. The method for preparing a polycarbonate resin according to claim 6, characterized in that: The catalyst is a nano-magnesium oxide catalyst.

8. The method for preparing a polycarbonate resin according to claim 6 or 7, characterized in that: The molar ratio of the total amount of the dihydroxy compounds in formula (a) and formula (b) to the carbonic acid diester compound is (0.98 - 1.02):

1.

9. The method for preparing a polycarbonate resin according to claim 6 or 7, characterized in that: The molar ratio of the catalyst to the carbonic acid diester compound is (0.01 - 0.05):

100.

10. An application of the polycarbonate resin according to any one of claims 1 - 5 or the polycarbonate resin prepared by the preparation method according to any one of claims 6 - 9 in optical materials.

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