Optical polycarbonate resin and manufacturing method thereof

Abstract

The invention provides polycarbonate optical resin and a manufacturing method thereof, the influence factor A of the polycarbonate optical resin is 1-1.15, preferably 1.01-1.12, the influence factor A is equal to A0 / A1, A0 is the melt index of 260 DEG C / 2.16 kg staying for 300 seconds, and A1 is the melt index of 260 DEG C / 2.16 kg staying for 1080 seconds. On the basis of keeping a high refractive index, the resin has more excellent thermal stability, yellowing resistance, long-period aging resistance and outstanding optical stability at high and low temperatures.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical resin, in particular to an optical polycarbonate resin and a manufacturing method thereof. BACKGROUND

[0002] In recent years, with the rapid development of electronic information technology, optical lenses are increasingly widely used in mobile intelligent terminals, automotive intelligentization, security monitoring and other fields. As a key component of optical lenses, the performance of lens materials directly affects the imaging quality. At present, optical lenses mainly use two materials: optical glass and optical resin. Compared with optical glass, optical resin has the advantages of easy molding, high production efficiency, light weight, etc., and has gradually become the mainstream material. However, with the development of optical lenses towards lightness, thinness and high imaging quality, the performance requirements of optical resin are continuously improved. Optical lenses can be divided into three categories according to design technology: plastic lenses, glass lenses and glass-plastic hybrid lenses. Plastic lenses have the lowest industrial difficulty and cost, have good mass production capacity, and are often used in daily life such as mobile phone cameras and digital cameras; glass lenses have complex process, good light transmittance and stability, and are often used in professional equipment such as single-lens reflex cameras and high-end scanners. The current market is monopolized by a few international giants; glass-plastic hybrid lenses reduce costs while ensuring product performance and stability, with indicators between plastic lenses and glass lenses, suitable for use in vehicle-mounted, digital cameras, security monitoring and many other fields.

[0003] At present, optical plastic materials mainly include cyclic olefin polymers and optical polycarbonates, and among them, optical polycarbonates have the advantages of high refractive index, easy molding, high production efficiency, etc. Thermoplastic resins formed from bisphenol A are widely used for optical lens applications, but as the use of optical lenses expands, it is necessary to further improve their refractive index.

[0004] In the early days, patent US4810771 proposed a high-refractive polyester resin material that can be used for optical lenses, which is prepared by using 9,9-bis-(4-hydroxyphenyl) fluorene as a monomer, but the refractive index product is difficult to meet the market demand of lenses in the future mobile phones, vehicles, security, VR / AR and other fields. Later, Konica patent JP2001072872 disclosed a thermoplastic resin material and its manufacturing method that can be used for optical lenses, mainly using 2,2-bis-(2-hydroxyethoxy)-1,1-binaphthalene as a polymerization monomer, which can be used to prepare polyester, polycarbonate, polyurethane, sulfone polymer and other optical resin materials, and the refractive index is higher, but the refractive index of the optical resin prepared only from this monomer still cannot meet the current market demand; CN112961336A discloses a polycarbonate resin with stable high refractive index, a preparation method and application, but does not mention the product's yellowing resistance and long-term aging resistance.

[0005] With the expansion of applications such as optical lenses, optical polycarbonate resins need to possess better thermal stability, yellowing resistance, and long-term aging resistance to meet the requirements of use in various extreme environments. Therefore, developing a polycarbonate optical resin that maintains a high refractive index while possessing excellent thermal stability, yellowing resistance, long-term aging resistance, and outstanding optical stability at high and low temperatures has become the focus and challenge of current research. Summary of the Invention

[0006] The purpose of this invention is to provide an optical resin and its manufacturing method. This optical resin, while maintaining a high refractive index, has superior thermal stability, resistance to yellowing, long-term aging resistance, and outstanding optical stability at high and low temperatures (relative haze and relative refractive index). It can meet the requirements for use in optical lenses, and the manufacturing method is simple, showing promise for industrial application.

[0007] To achieve the above objectives, in one respect, the present invention provides a polycarbonate optical resin comprising repeating units derived from the general formula (1):

[0008]

[0009] In general formula (1), R1 and R2 are independently hydrogen atoms, alkyl with 1 to 20 carbon atoms, alkoxy with 1 to 20 carbon atoms, cycloalkyl with 5 to 20 carbon atoms, cycloalkoxy with 5 to 20 carbon atoms, aryl with 6 to 20 carbon atoms, or aryloxy with 6 to 20 carbon atoms.

[0010] Examples of alkyl groups include methyl, ethyl, propyl, butyl, pentyl, and hexyl; examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentoxy, or hexoxy; examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and dicyclopentyl; examples of aryl groups include phenyl, tolyl, naphthyl, xylyl, etc.

[0011] The influence factor A of the polycarbonate optical resin is 1 to 1.15, preferably 1.01 to 1.12, wherein the influence factor A = A0 / A1, A0 is the melt index at 260℃ / 2.16kg for 300 seconds, and A1 is the melt index at 260℃ / 2.16kg for 1080 seconds.

[0012] The optical stability coefficient B of the polycarbonate optical resin is 1 to 2.5, preferably 1 to 2.0. The optical stability coefficient B = B1 / B0, where B0 represents the YI value of a 3mm specimen injected into an injection molding machine at 240°C, and B1 is the YI value of a 3mm specimen injected into an injection molding machine after the melt has been in the injection molding machine for 20 minutes under the same injection molding process as B0.

[0013] The polycarbonate optical resin has a weight-average molecular weight of 10,000 to 60,000 g / mol, preferably 20,000 to 40,000 g / mol;

[0014] The molecular weight distribution of the polycarbonate optical resin is ≤3, preferably ≤2.5, and more preferably ≤2;

[0015] The optical polycarbonate molecular chain end groups include one or more of phenoxy, toluoxy, chlorophenoxy, methyl, ethyl, butyl, cyclohexyl, and hydroxyl, preferably phenoxy and / or hydroxyl.

[0016] The polycarbonate optical resin has a refractive index nD of 1.6380 to 1.6410 at 23°C and a wavelength of 589 nm, and an Abbe number not higher than 25.

[0017] On the other hand, the present invention provides a method for manufacturing polycarbonate optical resin, wherein the method involves a melt transesterification reaction of a dihydroxy compound represented by formula (2) with a diester. This method can be employed as a continuous process or a batch process.

[0018]

[0019] In the general formula (2), R1 and R2 are independently hydrogen atoms, alkyl with 1 to 20 carbon atoms, alkoxy with 1 to 20 carbon atoms, cycloalkyl with 5 to 20 carbon atoms, cycloalkoxy with 5 to 20 carbon atoms, aryl with 6 to 20 carbon atoms, or aryloxy with 6 to 20 carbon atoms.

[0020] Examples of alkyl groups include methyl, ethyl, propyl, butyl, pentyl, and hexyl; examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentoxy, or hexoxy; examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and dicyclopentyl; examples of aryl groups include phenyl, tolyl, naphthyl, xylyl, etc.

[0021] Examples of the dihydroxy compounds include 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 9,9-bis(4-hydroxy-3-ethylphenyl)fluorene, 9,9-bis(4-hydroxy-3-n-propylphenyl)fluorene, 9,9-bis(4-hydroxy-3-isopropylphenyl)fluorene, 9,9-bis(4-hydroxy-3-n-butylphenyl)fluorene, 9,9-bis(4-hydroxy-3-sec-butylphenyl)fluorene, and 9,9 -Di(4-hydroxy-3-tert-butylphenyl)fluorene, 9,9-di(4-hydroxy-3-cyclohexylphenyl)fluorene, 9,9-di(4-hydroxy-2-phenylphenyl)fluorene, 9,9-di(4-hydroxy-3-phenylphenyl)fluorene, 9,9-di[4-hydroxy-3-(3-methylphenyl)phenyl]fluorene and other derived units, more preferably 9,9-di(4-hydroxy-3-phenylphenyl)fluorene and 9,9-di(4-hydroxy-3-methylphenyl)fluorene;

[0022] The preferred dicarbonate is diphenyl carbonate, dimethyl carbonate, bis(chlorophenyl) carbonate, m-cresol carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, and more preferably diphenyl carbonate.

[0023] In one specific embodiment, the preparation method includes at least the following steps:

[0024] Step 1): The dihydroxy compound shown in formula (2) is reacted with a mixture of carbonate diester, catalyst, antioxidant and heat stabilizer at 150-200°C and 70-101 kPa for 0.5-2 h.

[0025] Step 2): Based on Step 1), the reactants are reacted at 190–220°C and 40–70 kPa for 0.5–3 h with a stirring rate of 10–200 rpm.

[0026] Step 3): Based on Step 2), add dicarbonate raw material and react at 210-240℃ and 1-50 kPa for 0.5-3 hours with a stirring rate of 10-200 rpm.

[0027] Step 4): Further react at 220-240℃ and 100-600 Pa for 0.5-3 hours with a stirring rate of 10-200 rpm. After the reaction is completed, nitrogen gas is introduced to restore normal pressure, and the polycarbonate resin is discharged.

[0028] In step 1), the molar ratio of carbonate diester to dihydroxy compound is 1.01 to 1.1:1, preferably 1.02 to 1.06:1;

[0029] The stirring rate in step 1) is 10-200 rpm, preferably 30-100 rpm;

[0030] In step 1), the reactants undergo external circulation reaction, with a circulation frequency of 2 to 20 times / min, preferably 5 to 10 times / min.

[0031] The reaction described in this invention is as follows Figure 1 The reaction is carried out in the apparatus shown, which includes a reactor body, an external circulation outlet, an external circulation inlet, and a melt pump. The external circulation outlet and external circulation inlet are connected by an external circulation pipe. The melt pump is used for the circulation of the melt. The external circulation pipe is preferably equipped with heat tracing or insulation to ensure that the temperature inside the external circulation pipe is consistent with that of the reactor body.

[0032] The catalyst is an alkaline compound catalyst, preferably an alkali metal compound or an alkaline earth metal compound. Examples of alkali metal compounds include organic acid salts, inorganic salts, oxides, hydroxides, hydrides, or alkoxides of alkali metals. Examples include: sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, sodium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, lithium carbonate, sodium acetate, potassium acetate, cesium acetate, lithium acetate, sodium stearate, potassium stearate, cesium stearate, lithium stearate, sodium borohydride, sodium borophenylide, sodium benzoate, potassium benzoate, cesium benzoate, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium phenyl phosphate, disodium salt, dipotassium salt, dicesium salt, or dilithium salt of bisphenol A, sodium salt, potassium salt, cesium salt, or lithium salt of phenol, etc.

[0033] Examples of alkaline earth metal compounds include organic acid salts, inorganic salts, oxides, hydroxides, hydrides, and alkoxides. Specifically, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium bicarbonate, calcium bicarbonate, strontium bicarbonate, barium bicarbonate, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, magnesium acetate, calcium acetate, strontium acetate, barium acetate, magnesium stearate, calcium stearate, calcium benzoate, and magnesium phenyl phosphate are examples.

[0034] The catalyst content in the polycarbonate resin is preferably 1*10 molar amounts relative to the total molar amount of the dihydroxy compound, where 1 molar amount of catalyst is 1*10. -7 ~10 -4 mol;

[0035] The antioxidant is selected from triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. One or more of the following: benzylbenzyl, N,N-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrogenated cinnamamide), 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate diethyl ester, tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, and 3,9-bis{1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro(5,5)undecane;

[0036] The antioxidant content in the polycarbonate resin is preferably 0.001 to 0.3 parts by weight relative to 100 parts by weight of the polycarbonate resin;

[0037] The heat stabilizer is preferably a phosphorus-based heat stabilizer, such as phosphorous acid, phosphoric acid, phosphonic acid, phosphonic acid, and their esters. Specifically, examples include: triphenyl phosphite, tri(nonylphenyl) phosphite, tri(2,4-di-tert-butylphenyl) phosphite, tri(2,6-di-tert-butylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, tri(octadecyl) phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, bis(nonylphenyl)pentaerythritol diphosphite, bis(2,4- Diisopropylphenylphenyl) pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, di(octadecyl) pentaerythritol diphosphite, tributyl phosphate, triethyl phosphate, trimethyl phosphate, triphenyl phosphate, diphenyl mono-o-biphenyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, dimethyl phenylphosphonate, diethyl phenylphosphonate, dipropyl phenylphosphonate, tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyl diphosphonate, tetra(2,4-di-tert-butylphenyl)-4,3'-biphenyl diphosphonate, tetra(2,4-di-tert-butylphenyl)-3,3'-biphenyl diphosphonate, bis(2,4-di-tert-butylphenyl)-4-phenyl-phenyl phosphonate and bis(2,4-di-tert-butylphenyl)-3-phenyl-phenyl phosphonate, etc.;

[0038] The content of the heat stabilizer in the polycarbonate resin is preferably 0.001 to 0.3 parts by weight relative to 100 parts by weight of the polycarbonate resin;

[0039] Step 3) The reactants after the addition of diester carbonate are subjected to external circulation reaction, with a circulation rate of 2 to 20 times / min, preferably 5 to 10 times / min;

[0040] The molar ratio of the added diester in step 3) to the dihydroxy compound in step (1) is 0.001 to 0.1.

[0041] The beneficial effects of this invention are as follows:

[0042] The optical resin of this invention, while maintaining a high refractive index, has superior thermal stability, resistance to yellowing, long-term aging resistance, and outstanding optical stability at high and low temperatures (relative haze and relative refractive index). It can be used in optical lenses, infrared camera lenses, biometric camera lenses, and other fields. Optical lenses using the optical resin of this invention have excellent long-term optical stability and broad application prospects. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the external circulation reactor, where 1 is the reactor body, 2 is the external circulation outlet, and 3 is the external circulation inlet. Detailed Implementation

[0044] The present invention will now be described in conjunction with specific embodiments. It should be noted that the embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial improvements and adjustments made to the present invention based on its content are within the scope of protection of the present invention.

[0045] (1) Weight-average molecular weight (Mw): Gel permeation chromatography (GPC) was used with dichloromethane as the developing solvent. A standard curve was prepared using standard polystyrene with a known molecular weight (molecular weight distribution close to 1). Based on the standard curve, Mw and molecular weight distribution were calculated from the retention time of GPC.

[0046] (2) Impact Factor: The impact factor A is defined as A0 / A1, where A0 is the melt index at 260℃ / 2.16kg for 300 seconds and A1 is the melt index at 260℃ / 2.16kg for 1080 seconds.

[0047] (3) Optical stability coefficient: The optical stability coefficient B is defined as B1 / B0, where B0 represents the YI value of a 3mm specimen injected into the injection molding machine at 240℃, and B1 is the YI value of a 3mm specimen injected into the injection molding machine after the melt has stayed in the injection molding machine for 20 minutes under the same injection molding process as B0.

[0048] YI value test: The YI value of the test piece was obtained by testing with an UltraScan PRO colorimeter. The powder was injection molded into a 3mm thick test piece using a Haitian MA900II1260 injection molding machine.

[0049] (4) Relative refractive index test: For a 1 mm thick film made of the optical resin prepared in the examples, the refractive index (nD1) of the optical resin of the present invention at 23 °C and a wavelength of 589 nm was measured using an Abbe refractometer according to the method of JIS-K-7142.

[0050] -40℃ Relative Refractive Index: Place three samples for refractive index testing in a -40℃ refrigerator for 12 hours. After taking them out, quickly test the refractive index (complete the test within 2 minutes). Take the average value of the three samples. The refractive index is nD2. -40℃ Relative Refractive Index = |nD1-nD2| / nD1*100%.

[0051] Relative refractive index at 80℃: Place three samples for refractive index testing in an 80℃ oven for 12 hours, remove them and quickly test the refractive index (complete the test within 2 minutes). Take the average value of the three samples. The refractive index is nD3. Relative refractive index at 80℃ = |nD1-nD3| / nD1*100%.

[0052] (5) Relative haze: Haze was tested according to ASTM D1003 standard. The specimen thickness was 3 mm, and the haze of the specimen at 23℃ was V0.

[0053] -40℃ relative haze: Place three samples for refractive index testing in a -40℃ refrigerator for 12 hours. After taking them out, quickly test the haze (complete the test within 2 minutes). Take the average value of the three samples, and the haze is V1. -40℃ relative haze = |V1-V0| / V0*100%.

[0054] Relative haze at 80℃: Place three samples for refractive index testing in an 80℃ refrigerator for 12 hours. After taking them out, quickly test the haze (complete the test within 2 minutes). Take the average value of the three samples. The haze is V2. Relative haze at 80℃ = |V2-V0| / V0*100%.

[0055] (6) Tensile strength retention rate: The tensile strength was tested according to ASTM D638 standard. The initial value was recorded as X0. After the tensile specimen was placed at 85% ℃ and 85% humidity for 1000h, it was taken out and the tensile strength was tested as X1. Retention rate = (X0-X1) / X0*100%.

[0056] (7) Abbe number: For the 0.1 mm thick polycarbonate resin film prepared in the examples, the refractive index at wavelengths of 486 nm, 589 nm and 656 nm at 23 °C was measured using an Abbe refractometer. The Abbe number ν was then calculated using the following formula: ν = (nD - 1) / (nF - nC), where nD is the refractive index of the material at a wavelength of 589.3 nm, nF is the refractive index of the material at a wavelength of 486.1 nm and nC is the refractive index of the material at a wavelength of 656.3 nm.

[0057] The raw materials used in the embodiments and comparative examples of this invention are all commercially available products, and their sources are as follows:

[0058] 9,9-Bis(4-hydroxyphenyl)fluorene (BPEF) was purchased from Jiangsu Yongxing Chemical; DPC was purchased from Aladdin Reagent; antioxidants and catalysts were both purchased from Aladdin.

[0059] Example 1

[0060] Add 75 kg of 9,9-bis(4-hydroxyphenyl)fluorene (BPEF), 36.63 kg of diphenyl carbonate (DPC), 160 g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1010), 160 g of pentaerythritol diphosphite (PEP36), and 0.14 g of sodium bicarbonate solid to a 300 L polymerization reactor equipped with a stirrer. Purge the reactor with nitrogen four times, each time reducing the nitrogen pressure to 0.1 MPa and then restoring it to atmospheric pressure. Start heating and raise the temperature. Once the temperature reaches 120 °C, start stirring at a speed of 50 rpm. After reaching 90℃, the control system pressure was set to 80 kPa, and the melt pump was started simultaneously with a flow rate of 8.96 kg / min (first stage cycle count: 5 times). After 1.5 hours of reaction, the temperature was increased to 210℃, the pressure decreased to 50 kPa, and the stirring speed was set to 50 rpm for an additional 0.5 hours. Then, 1.1 kg of DPC was added to the system, the temperature was increased to 220℃, the pressure decreased to 35 kPa, and the pump flow rate was set to 44.8 kg / min (second stage cycle count: 10 times) for a reaction time of 1 hour. Finally, the temperature was increased to 230℃, the pressure decreased to 200 Pa, and the reaction time was 1.5 hours to terminate the reaction. After the reaction, nitrogen was introduced into the system to restore atmospheric pressure, and the resulting optical resin was removed for performance evaluation.

[0061] The preparation methods of Examples 2-6 and Comparative Examples 1-4 are the same as those of Example 1. The types and quality of antioxidant catalysts are the same as those of Example 1. The difference is the feeding ratio and the number of cycles, as detailed in Table 1 below:

[0062] Table 1

[0063]

[0064]

[0065] The test data for the examples and comparative examples are shown in Table 2 below:

[0066] Table 2

[0067] The data comparison above shows that the optical resin of the present invention, while maintaining a high refractive index, has superior thermal stability, yellowing resistance, long-term aging resistance, and outstanding optical stability (relative haze and relative refractive index) at high and low temperatures.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A polycarbonate optical resin comprising a repeating unit derived from the general formula (1): ###0001### wherein R1 and R2 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkoxy group having 5 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aryloxy group having 6 to 20 carbon atoms; the polycarbonate optical resin has an influence factor A of 1 to 1.15, preferably 1.01 to 1.12, wherein the influence factor A = A0 / A1, A0 is a melt index at 260°C / 2.16 kg for 300 seconds, and A1 is a melt index at 260°C / 2.16 kg for 1080 seconds. The polycarbonate optical resin has an optical stability factor B of 1 to 2.5, preferably 1 to 2.0, wherein the optical stability factor B = B1 / B0, B0 is a YI value of a 3 mm test piece molded in an injection molding machine at 240°C, and B1 is a YI value of a 3 mm test piece molded in the same molding process as B0 after the melt is left in the injection molding machine for 20 minutes.

2. The polycarbonate optical resin according to claim 1, wherein The polycarbonate optical resin has a weight average molecular weight of 10,000 to 60,000 g / mol, preferably 20,000 to 40,000 g / mol; and / or, the polycarbonate optical resin has a molecular weight distribution of ≤ 3, preferably ≤ 2.5, more preferably ≤ 2.

3. The polycarbonate optical resin according to claim 1 or 2, wherein The manufacturing method is a melt transesterification reaction of a dihydroxy compound represented by the general formula (2) with a carbonic acid diester, ###0002### wherein R1 and R2 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, a cycloalkoxy group having 5 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aryloxy group having 6 to 20 carbon atoms. The dihydroxy compound is selected from one or more of 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 9,9-bis(4-hydroxy-3-ethylphenyl)fluorene, 9,9-bis(4-hydroxy-3-n-propylphenyl)fluorene, 9,9-bis(4-hydroxy-3-isopropylphenyl)fluorene, 9,9-bis(4-hydroxy-3-n-butylphenyl)fluorene, 9,9-bis(4-hydroxy-3-sec-butylphenyl)fluorene, 9,9-bis(4-hydroxy-3-tert-butylphenyl)fluorene, 9,9-bis(4-hydroxy-3-cyclohexylphenyl)fluorene, 9,9-bis(4-hydroxy-2-phenylphenyl)fluorene, 9,9-bis(4-hydroxy-3-phenylphenyl)fluorene, 9,9-bis[4-hydroxy-3-(3-methylphenyl)phenyl]fluorene, preferably 9,9-bis(4-hydroxy-3-phenylphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene.

4. The method for producing a polycarbonate optical resin according to any one of claims 1 to 3, wherein The carbonic acid diester is selected from one or more of diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, m-cresyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, preferably diphenyl carbonate. The manufacturing method comprises at least the following steps, 5. The production method according to claim 4, wherein ​ 6. The production method according to claim 4 or 5, characterized by, ​ 7. The production method according to any one of claims 4 to 6, wherein ​ Step 1): the mixture of dihydroxy compound shown in formula (2), carbonic acid diester, catalyst, antioxidant and thermal stability agent is reacted at 150-200℃ under pressure of 70kpa-101kpa for 0.5-2h; Step 2): on the basis of step 1), the reactants are reacted at 190-220℃ under pressure of 40-70kpa for 0.5-3h with stirring rate of 10-200rpm; Step 3): on the basis of step 2), carbonic acid diester raw material is added and reacted at 210-240℃ under pressure of 1-50kpa for 0.5-3h with stirring rate of 10-200rpm; Step 4): further reacted at 220-240℃ under pressure of 100-600pa for 0.5-3h with stirring rate of 10-200rpm, and after the reaction, nitrogen is introduced to restore normal pressure, and the product is discharged to obtain polycarbonate resin.

8. The production method according to claim 7, wherein In step 1), the molar ratio of carbonic acid diester to dihydroxy compound is 1.01-1.1:1, preferably 1.02-1.06:1; and / or, the stirring rate in step 1) is 10-200rpm, preferably 30-100rpm; and / or, the reactant in step 1) is subjected to external circulation reaction, and the circulation frequency is 2-20 times / min, preferably 5-10 times / min.

9. The production method according to claim 7 or 8, characterized by, After the addition of carbonic acid diester in step 3), the reactant is subjected to external circulation reaction, and the circulation frequency is 2-20 times / min, preferably 5-10 times / min; and / or, the molar ratio of the added carbonic acid diester in step 3) to the dihydroxy compound in step (1) is 0.001-0.1.

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