A high-refractive cycloolefin copolymer and a method for preparing the same

Abstract

The application provides a high-refraction cycloolefin copolymer and a preparation method thereof, and has a structure of formula I. The cycloolefin copolymer can obtain a cycloolefin copolymer resin with high thermal stability due to high steric hindrance of the cycloolefin monomer. The refractive index of the cycloolefin copolymer resin is greatly improved due to R3 and R4 on the cycloolefin monomer, and is first broken through to above 1.70, while maintaining high light transmittance of 91.0-96.0%, extremely low water absorption (<0.01%), and a glass transition temperature of 219 DEG C. The application prepares the cycloolefin copolymer resin with high activity, adjustable molecular weight and glass transition temperature by adjusting the reaction conditions. The copolymer resin has high refractive index, high light transmittance, heat resistance, low birefringence and moisture absorption, excellent fluidity, moldability and dimensional stability.

Description

Technical Field

[0001] This invention belongs to the field of organic technology, and particularly relates to a high-refractive-index cyclic olefin copolymer and its preparation method. Background Technology

[0002] Cyclic olefin copolymers (COCs) are generally prepared by the addition copolymerization of ethylene or α-olefins with cyclic olefins. They possess excellent properties such as low density, high transparency, good thermal stability, high refractive index, and strong chemical resistance. Since their first synthesis in the 1990s, COCs have become one of the important engineering plastics, applicable in the fields of optics, displays, medicine, and low-dielectric materials. Their development is shifting towards high-end, applicable resin materials.

[0003] Currently, Mitsui Chemicals and Polyplastics of Japan have launched commercially available COCs under the trade names APEL and Topas, respectively. Refractive index is an important indicator of optical materials. Here, COC materials are defined as having a medium refractive index of 1.50-1.55, a high refractive index of 1.60, and an ultra-high refractive index of 1.70. One of the biggest problems with current COCs is their relatively low refractive index compared to other optical materials such as polycarbonate (PC), which severely limits their applications. The refractive index of current COC resins is generally between 1.51 and 1.55, and the availability of cyclic olefin monomers limits further improvements in the refractive index of cyclic olefin resins. Existing authorized patents (ZL202210898013.X) and published Chinese invention patent applications (202310033135.7) have achieved refractive indices of COCs exceeding 1.57 and 1.60, respectively, but a breakthrough to an ultra-high refractive index of 1.70 has not yet been achieved. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a high refractive index cyclic olefin copolymer and a method for preparing the same, wherein the cyclic olefin copolymer has ultra-high refractive index and high light transmittance.

[0005] This invention provides a cyclic olefin copolymer having the structure of Formula I:

[0006]

[0007] 20≥X:Y≥1, 2500≥n≥10, p is 0 or 1;

[0008] R1 and R2 are independently selected from hydrogen or C1 to C10 saturated aliphatic hydrocarbon groups;

[0009] The R3 is selected from hydrogen, diphenylamino, carbazole, diphenyl, fluorenyl, biphenyl, naphthalene, pyrene, anthracene, phenanthrene, acenaphthene, chlorophenanthrene, fluorine, chlorine, bromine, iodine, phenyl and their derivatives;

[0010] R4 is selected from diphenylamino, carbazole, diphenyl, fluorenyl, biphenyl, naphthalene, pyrene, anthracene, phenanthrene, acenaphthene, chlorophenanthrene, chlorophenanthrene, fluorine, chlorine, bromine, iodine, phenyl and their derivatives.

[0011] Preferably, R1 and R2 are independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or hydrogen.

[0012] Preferably, the cyclic olefin copolymer is specifically selected from any one of formulas a to v:

[0013]

[0014]

[0015] Preferably, the cyclic olefin copolymer has a refractive index of 1.6488 to 1.7083, a glass transition temperature of 92°C to 219°C, a weight-average molecular weight of 56 kg / mol to 139 kg / mol, and a molecular weight distribution of 1.9 to 2.5.

[0016] This invention provides a method for preparing the high-refractive-index cyclic olefin copolymer described above, comprising the following steps:

[0017] In an inert solvent, a cyclic olefin monomer having the structure of formula II and ethylene or α-olefin are polymerized in the presence of a metallocene catalyst to obtain a cyclic olefin copolymer having the structure of formula I.

[0018]

[0019] The R3 is selected from hydrogen, diphenylamino, carbazole, diphenyl, fluorenyl, biphenyl, naphthalene, pyrene, anthracene, phenanthrene, acenaphthene, chlorophenanthrene, fluorine, chlorine, bromine, iodine, phenyl and their derivatives;

[0020] R4 is selected from diphenylamino, carbazole, diphenyl, fluorenyl, biphenyl, naphthalene, pyrene, anthracene, phenanthrene, acenaphthene, chlorophenanthrene, chlorophenanthrene, fluorine, chlorine, bromine, iodine, phenyl and their derivatives.

[0021] Preferably, the α-olefin is propylene, 1-butene, isobutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, or 2-ethyl-1-butene.

[0022] Preferably, the metallocene catalyst is selected from non-bridged zirconium dichloride catalysts, isopropylidene-bridged indene zirconium dichloride catalysts, isopropylidene-bridged fluorene zirconium dichloride catalysts, isopropylidene-bridged tert-butylfluorene zirconium dichloride catalysts, diphenyl-bridged fluorene zirconium dichloride catalysts, dimethylsilyl-bridged fluorene zirconium dichloride catalysts, dimethylsilyl-bridged tert-butylamine titanium dichloride catalysts, or dimethylsilyl-bridged fluorene tert-butylamine titanium dichloride catalysts.

[0023] Preferably, the cyclic olefin monomer having the structure of Formula II is selected from any one of Formulas 1 to 22:

[0024]

[0025] Preferably, the molar ratio of the metallocene catalyst to the cyclic olefin monomer having the structure of formula II is 1:50 to 2500;

[0026] The molar ratio of the ethylene or α-olefin to the cyclic olefin monomer having the structure of Formula II is (0.5–25):1.

[0027] Preferably, the polymerization reaction is carried out at a temperature of 30–140°C for a time of 5–240 min.

[0028] This invention provides a high-refractive-index cyclic olefin copolymer with the structure of Formula I. Due to the high steric hindrance of the cyclic olefin monomers, the cyclic olefin copolymer resin exhibits high thermal stability. Furthermore, the introduction of R3 and R4 groups into the cyclic olefin copolymer increases its refractive index. This invention prepares a highly reactive cyclic olefin copolymer resin with adjustable molecular weight and glass transition temperature by adjusting the reaction conditions. This copolymer resin, while possessing a high refractive index, also exhibits high light transmittance, heat resistance, low birefringence and hygroscopicity, excellent flowability, moldability, and dimensional stability. Attached Figure Description

[0029] Figure 1 NMR of the binary cyclic olefin copolymer of Example 10 of the present invention 13 C-NMR spectrum;

[0030] Figure 2 NMR of the binary cyclic olefin copolymer of Example 12 of the present invention 1 H-NMR spectrum;

[0031] Figure 3 This is a DSC curve of the binary cyclic olefin copolymer of Example 17 of the present invention;

[0032] Figure 4 This is a TGA curve of the binary cyclic olefin copolymer of Example 18 of the present invention;

[0033] Figure 5 This is a comparison chart of the refractive indices of the binary cyclic olefin copolymers of Examples 9, 13, and 17 of the present invention;

[0034] Figure 6 This is a visible light transmittance curve of the binary cyclic olefin copolymer of Example 14 of the present invention. Detailed Implementation

[0035] This invention provides a high-refractive-index cyclic olefin copolymer having the structure of Formula I:

[0036]

[0037] 20≥X:Y≥1, 2500≥n≥10, p is 0 or 1;

[0038] R1 and R2 are independently selected from hydrogen or C1 to C10 saturated aliphatic hydrocarbon groups;

[0039] R3 is selected from hydrogen, diphenylamino, carbazole, diphenyl, fluorenyl, biphenyl, naphthalene, pyrene, anthracene, phenanthrene, acenaphthene, chlorophenanthrene, fluorine, chlorine, bromine, iodine, phenyl and their derivatives; R4 is selected from diphenylamino, carbazole, diphenyl, fluorenyl, biphenyl, naphthalene, pyrene, anthracene, phenanthrene, acenaphthene, chlorophenanthrene, fluorine, chlorine, bromine, iodine, phenyl and their derivatives.

[0040] In this invention, R1 and R2 are independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or hydrogen.

[0041] In this invention, 1.3≤X:Y≤19.5, more preferably 1.5≤X:Y≤19.

[0042] The cyclic olefin copolymers described in this invention are specifically selected from any one of formulas a to v:

[0043]

[0044]

[0045] The cyclic olefin copolymer described in this invention has a refractive index of 1.6488–1.7083, a glass transition temperature of 92°C–219°C, and a molecular weight distribution of 1.9–2.5. The weight-average molecular weight of the cyclic olefin copolymer is 56 kg / mol–139 kg / mol, preferably 70–129 kg / mol. The cyclic olefin copolymer provided by this invention improves the steric hindrance of the cyclic olefin monomer, resulting in a cyclic olefin copolymer resin with high thermal stability. Furthermore, the introduction of R3 and R4 groups onto the cyclic olefin monomer increases the refractive index of the cyclic olefin copolymer resin.

[0046] The structural formula of the cyclic olefin copolymer prepared using cyclic olefin monomer 1 is as follows:

[0047]

[0048] The structural formula of the cyclic olefin copolymer prepared using cyclic olefin monomer 3 is as follows:

[0049]

[0050] The structural formula of the cyclic olefin copolymer prepared using cyclic olefin monomer 4:

[0051]

[0052] The structural formula of the cyclic olefin copolymer prepared using cyclic olefin monomer 8:

[0053]

[0054] The structural formula of the cyclic olefin copolymer prepared using cyclic olefin monomer 11 is as follows:

[0055]

[0056] The structural formula of the cyclic olefin copolymer prepared using cyclic olefin monomer 13 is as follows:

[0057]

[0058] The structural formula of the cyclic olefin copolymer prepared using cyclic olefin monomer 17:

[0059]

[0060] This invention provides a method for preparing the high-refractive-index cyclic olefin copolymer described above, comprising the following steps:

[0061] In an inert solvent, a cyclic olefin monomer having the structure of formula II and ethylene or α-olefin are polymerized in the presence of a metallocene catalyst to obtain a cyclic olefin copolymer having the structure of formula I.

[0062]

[0063] R3 is selected from hydrogen, diphenylamino, carbazole, diphenyl, fluorenyl, biphenyl, naphthalene, pyrene, anthracene, phenanthrene, acenaphthene, chlorophenanthrene, fluorine, chlorine, bromine, iodine, phenyl and their derivatives; R4 is selected from diphenylamino, carbazole, diphenyl, fluorenyl, biphenyl, naphthalene, pyrene, anthracene, phenanthrene, acenaphthene, chlorophenanthrene, fluorine, chlorine, bromine, iodine, phenyl and their derivatives.

[0064] This invention utilizes cyclic olefin monomers with Formula II structure as sterically hindered cyclic olefin monomers containing high refractive index groups. During copolymerization with ethylene or α-olefins, these monomers exhibit chain rigidity and high refractive index, resulting in cyclic olefin copolymers with high glass transition temperatures and refractive indices, demonstrating significant practical value. Experimental results show that the insertion rate of cyclic olefin monomers with Formula II structure in the cyclic olefin copolymers provided by this invention is adjustable between 14.3 mol% and 31.7 mol%, and their glass transition temperature can reach 219 °C. When the glass transition temperature of the cyclic olefin copolymer is 176 °C, its refractive index is 1.7016, yielding a series of novel high-glass transition temperature, ultra-high refractive index, high-performance cyclic olefin copolymer resins.

[0065] The cyclic olefin monomer having the structure of Formula II described in this invention is preferably any one of Formulas 1 to 22:

[0066]

[0067] This invention does not impose any special restrictions on the source of the cyclic olefin monomers having the structure of Formula II described above; they can be commercially available products or prepared in-house using methods well known to those skilled in the art. This invention also does not impose any special restrictions on the preparation method of the cyclic olefin monomers having the structure of Formula II.

[0068] The present invention prepares cyclic olefin copolymers in an inert solvent; the inert solvent is preferably a straight-chain hydrocarbon compound, a cyclic hydrocarbon compound, or an aromatic hydrocarbon compound, more preferably a benzene compound; in a specific embodiment, the inert solvent is toluene.

[0069] The copolymerization reaction described in this invention is carried out in the presence of a metallocene catalyst; the metallocene catalyst is preferably selected from the following: a non-bridged zirconium dichloride catalyst (Cat1), an isopropylidene-bridged indene zirconium dichloride catalyst (Cat2), an isopropylidene-bridged fluorene zirconium dichloride catalyst (Cat3), an isopropylidene-bridged tert-butylfluorene zirconium dichloride catalyst (Cat4), a diphenyl-bridged fluorene zirconium dichloride catalyst (Cat5), a dimethylsilyl-bridged fluorene zirconium dichloride catalyst (Cat6), a dimethylsilyl-bridged tert-butylamine titanium dichloride catalyst (Cat7), or a dimethylsilyl-bridged tert-butylamine titanium dichloride catalyst (Cat8). The structural formulas of catalysts Cat1 to Cat8 are as follows:

[0070]

[0071] This invention employs an inert solvent to first dissolve a cyclic olefin monomer having the structure of Formula II and a catalyst, respectively, to obtain a cyclic olefin monomer solution and a catalyst solution having the structure of Formula II. The cyclic olefin monomer solution having the structure of Formula II, the catalyst solution, and ethylene or an α-olefin are then added to the inert solvent to carry out a copolymerization reaction. In this invention, the α-olefin is preferably propylene, 1-butene, isobutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, or 2-ethyl-1-butene, and more preferably ethylene, propylene, 1-butene, isobutene, 1-pentene, 3-methyl-1-butene, 1-hexene, or 3-methyl-1-pentene. In specific embodiments, the α-olefin is propylene or hexene.

[0072] In this invention, the molar ratio of the metallocene catalyst to the cyclic olefin monomer having the structure of formula II is 1:50 to 2500; preferably 1:100 to 2000. The molar ratio of the ethylene or α-olefin to the cyclic olefin monomer having the structure of formula II is (0.5 to 25):1, preferably (1 to 20):1.

[0073] In this invention, when the ethylene or α-olefin is ethylene, since ethylene is in a gaseous state, the reaction solution is preferably filled with ethylene gas, and ethylene gas is continuously introduced into the reactor to maintain the ethylene pressure preferably from 1 atmosphere to 10 atmospheres, more preferably from 1 atmosphere to 4 atmospheres, and most preferably 1 atmosphere.

[0074] In this invention, during the polymerization reaction, the cyclic olefin monomer with Formula II has a relatively large steric hindrance, resulting in a cyclic olefin copolymer with a high glass transition temperature at a relatively low cyclic olefin monomer insertion rate. The introduction of the cyclic olefin monomer with Formula II into the cyclic olefin copolymer increases the refractive index of the resulting cyclic olefin copolymer material. Furthermore, this invention uses a metallocene catalyst as the main catalyst. During the polymerization reaction, this main catalyst exhibits excellent copolymerization catalytic ability, promoting the copolymerization reaction of the cyclic olefin monomer with Formula II with ethylene or α-olefins, thereby giving the polymerization reaction of this invention high reactivity. The polymerization reaction temperature in this invention is 30–140°C, and the time is 5–240 min.

[0075] After the polymerization reaction is completed, the present invention preferably performs post-treatment on the reaction solution obtained from the polymerization reaction. Specifically, the present invention can mix the reaction solution with an ethanol solution of hydrochloric acid to terminate the growth of the polymerization chain and obtain the reaction product; the reaction product is then subjected to solid-liquid separation and dried to obtain a cyclic olefin copolymer. The present invention does not have any particular limitation on the method of terminating the polymerization chain growth; the above-mentioned method of mixing the reaction solution with an ethanol solution of hydrochloric acid can be used, wherein the volume fraction of the ethanol solution of hydrochloric acid is preferably 5% to 15%. The present invention preferably uses filtration to separate the reaction product into solid and liquid components, and washes the filtered product; the washing reagent is preferably acetone, and the washing is preferably performed twice. The present invention does not have any particular limitation on the drying method; any drying technique well known to those skilled in the art can be used. In the present invention, the drying is vacuum drying, the vacuum drying temperature is 50℃ to 80℃, and the vacuum drying time is preferably 16 to 24 hours.

[0076] The present invention performs structural identification and performance testing on the above-mentioned cyclic olefin copolymers, and the specific process is as follows:

[0077] This invention uses nuclear magnetic resonance spectroscopy to determine the molecular structure of the copolymer; differential thermal analysis to determine the melting temperature or glass transition temperature of the polymer; and gel permeation chromatography to determine the molecular weight and molecular weight distribution index of the polymer.

[0078] Among them, nuclear magnetic resonance spectroscopy refers to the polymer's 1 H and 13 C10 NMR spectra were measured at 25°C using a Varian Unity-400 NMR spectrometer, with TMS as the internal standard and deuterated chloroform as the solvent (high temperature 110°C, deuterated tetrachloroethane as the solvent). Differential thermal analysis (DSC) was performed to determine the glass transition temperature of the polymer using a Perkin-Elmer Pyris 1 DSC differential scanning calorimeter, with a heating / cooling rate of 20°C / min and two scans. Thermogravimetric analysis (TGA) was performed using a Perkin-Elmer Pyris 1 instrument. Refractive index was measured at 20°C using an Abbe refractometer (DR-M4, Atago Co., Ltd., Tokyo, Japan) without contact liquid. Transmittance was measured using a Shimadzu UV-3600 UV-Vis-NIR spectrophotometer, with wavelengths ranging from 400 to 800 nm. Gel permeation chromatography (GPC) refers to the determination of the molecular weight and molecular weight distribution index of polymers using a Waters 1525 gel permeation chromatograph; an RI-Laser detector is used, trichlorobenzene is used as the solvent, the test temperature is 150℃, the flow rate is 1.0 mL / min, and PL EasiCal PS-1 is used as the standard.

[0079] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, of a high-refractive-index cyclic olefin copolymer and its preparation method, should not be construed as limiting the scope of protection of the present invention.

[0080] Example 1

[0081] Preparation process of cyclic olefin monomer 1:

[0082]

[0083] 9-Bromophenanthrene (20.0 g, 77.7 mmol), norbornadiene (21.5 g, 233.3 mmol), sodium formate (26.0 g, 382.3 mmol), and bis(triphenylphosphine)palladium dichloride (1.5 g, 2.1 mmol) were added to a toluene (300 mL) solution. The mixture was stirred at 120 °C for approximately 24 hours. The solvent was removed by rotary evaporation, and the crude product was purified by silica gel chromatography, eluting with a 0-30% ethyl acetate / hexane gradient to give a white solid cyclic olefin monomer 1 (13.7 g, 65%).

[0084] MRI 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 8.75 (m, 1H), 8.66 (m, 1H), 8.12 (m, 1H), 7.86 (m, 1H), 7.69--7.56 (m, 5 H),6.41(m,1H),6.32(m,1H),3.30(m,2H),3.04(m,1H),1.96(m,1H),1.83–-1.81(m,1H),1.72-1.63(m,2H).

[0085] Example 2

[0086] Preparation process of cyclic olefin monomer 3:

[0087]

[0088] 1-Bromopyrene (20.0 g, 71.1 mmol), norbornadiene (21.5 g, 233.3 mmol), sodium formate (26.0 g, 382.3 mmol), and bis(triphenylphosphine)palladium dichloride (1.5 g, 2.1 mmol) were added to a toluene (300 mL) solution. The mixture was stirred at 120 °C for approximately 24 hours. The solvent was removed by rotary evaporation, and the crude product was purified by silica gel chromatography, eluting with a 0-30% ethyl acetate / hexane gradient to give a white solid cyclic olefin monomer 3 (12.1 g, 58%).

[0089] MRI 1H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 8.30 (m, 1H), 8.18--8.09 (m, 4H), 8.04-7.97 (m, 4H), 6.44 (m, 1H), 6.35(m,1H),3.62(m,1H),3.33(m,1H),3.08(m,1H),2.08(m,1H),1.85(m,1H),1.80(m,1H),1.67(m,1H).

[0090] Example 3

[0091] Preparation process of cycloolefin monomer 4:

[0092]

[0093] 2-Bromo-9,9'-–spirobi[9H-fluorene] (20.0 g, 50.6 mmol), norbornadiene (21.5 g, 233.3 mmol), sodium formate (26.0 g, 382.3 mmol), and bis(triphenylphosphine)palladium dichloride (1.5 g, 2.1 mmol) were added to a toluene (300 mL) solution. The mixture was stirred at 120 °C for approximately 24 hours. The solvent was removed by rotary evaporation, and the crude product was purified by silica gel chromatography, eluting with a 0–30% ethyl acetate / hexane gradient to give a white solid cyclic olefin monomer 4 (16.3 g, 79%).

[0094] MRI 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 7.85-7.75 (m, 4H), 7.39-7.30 (m, 4H), 7.12-7.04 (m, 3H), 6.74-76.62 (m, 4H), 6.1 2(m,1H),6.07(m,1H),2.85(s,1H),2.72(s,1H),2.54(m,1H),1.62-1.58(m,1H),1.47(m,1H),1.39(m,1H),1.30(m,1H).

[0095] Example 4

[0096] Preparation process of cycloolefin monomer 8:

[0097]

[0098] 9-Iodophenanthrene (22.8 g, 75.0 mmol), 9-boronic acid phenanthrene (21.6 g, 97.5 mmol), norbornadiene (21.5 g, 233.3 mmol), potassium carbonate (27.0 g, 195.0 mmol), and bis(triphenylphosphine)palladium dichloride (1.5 g, 2.1 mmol) were added to a tetrahydrofuran (300 ml) solution. The mixture was stirred at 60 °C for approximately 24 hours. The solvent was removed by rotary evaporation, and the crude product was purified by silica gel chromatography, eluting with a 0-30% ethyl acetate / hexane gradient to give a white solid cyclic olefin monomer 8.

[0099] Example 5

[0100] Preparation process of cycloolefin monomer 11:

[0101]

[0102] 2-Iodo-9,9'-–spirodi[9H-fluorene] (22.8 g, 75.0 mmol), 2-boronic acid-9,9'-–spirodi[9H-fluorene] (21.6 g, 97.5 mmol), norbornadiene (21.5 g, 233.3 mmol), potassium carbonate (27.0 g, 195.0 mmol), and bis(triphenylphosphine)palladium dichloride (1.5 g, 2.1 mmol) were added to a tetrahydrofuran (300 ml) solution. The mixture was stirred at 60 °C for approximately 24 hours. The solvent was removed by rotary evaporation, and the crude product was purified by silica gel chromatography, eluting with a 0-30% ethyl acetate / hexane gradient to give a white solid cyclic olefin monomer 11.

[0103] Example 6

[0104] Preparation process of cycloolefin monomer 13:

[0105]

[0106] 5-norbornene-2,3-dibromo (15.4 g, 61.3 mmol), carbazole (10.0 g, 59.8 mmol), and anhydrous potassium carbonate (24.0 g, 173.6 mmol) were added to N,N-dimethylformamide (300 mL). The mixture was heated to reflux and stirred for approximately 24 hours. After removing the solvent, the crude product was purified by silica gel chromatography, eluting with a 0-30% ethyl acetate / hexane gradient to give a pale yellow solid monomer 13.

[0107] Example 7

[0108] Preparation process of cycloolefin monomer 17:

[0109]

[0110] 1-Bromopyrene (20.0 g, 71.1 mmol), tetracyclododecadiene (36.9 g, 233.3 mmol), sodium formate (26.0 g, 382.3 mmol), and bis(triphenylphosphine)palladium dichloride (1.5 g, 2.1 mmol) were added to a toluene (300 mL) solution. The mixture was stirred at 120 °C for approximately 24 hours. The solvent was removed by rotary evaporation, and the crude product was purified by silica gel chromatography, eluting with a 0-30% ethyl acetate / hexane gradient to give a white solid cyclic olefin monomer 17.

[0111] Example 8

[0112] Preparation of cyclic olefin copolymer C:

[0113]

[0114] First, a 75 mL glass pressure reactor connected to the gas pipeline was vacuum dried at 110 °C for 1 h. Then, under an inert atmosphere, 8 mL of toluene and 2.94 g of the cyclic olefin monomer 3 prepared in Example 2 were added to the reactor. Next, 5.0 μmol of Cat3 (isopropylidene-bridged fluorene-containing zirconium dichloride catalyst) was dissolved in 2 mL of toluene and injected into the polymerization system via a syringe. Ethylene was introduced under rapid stirring (750 rpm) and maintained at 1 bar. After 10 min, the pressure reactor was emptied, and 200 mL of hydrochloric acid-ethanol was added to quench the polymerization reaction. The polymer was filtered and dried to constant weight in a vacuum oven, yielding 2.14 g of polymer. The insertion ratio of the cyclic olefin monomer in the obtained polymer represents X:Y, and the molecular weight of the obtained polymer represents n.

[0115] Examples 9-30

[0116] The effect of the type and concentration of cyclic olefin monomers on the copolymerization of ethylene and cyclic olefin monomers catalyzed by metallocene catalysts:

[0117] First, a 75 mL glass pressure reactor connected to the gas pipeline was vacuum dried at 100 °C for at least 1 h. Then, under an inert atmosphere, 8 mL of toluene and a specific amount of a specific type of cyclic olefin monomer were added to the reactor. Next, 5.0 μmol of Cat3 (isopropylidene-bridged zirconium dichloride catalyst) was dissolved in 2 mL of toluene and injected into the polymerization system via a syringe. Ethylene was introduced and maintained at 1 bar under rapid stirring (750 rpm), keeping the polymerization temperature at 70 °C. After a specific time, the pressure reactor was emptied, 200 mL of hydrochloric acid-ethanol was added to quench the polymerization reaction, the polymer was filtered, and dried to constant weight in a vacuum oven. Specific reaction conditions and results are shown in Table 1.

[0118] Table 1

[0119]

[0120]

[0121] Note: All data are based on results from at least two parallel experiments (unless otherwise stated). Activity: in gmol -1 h -1 Unit: M w M w / M n These represent weight-average molecular weight and polymer dispersibility index, respectively, determined by GPC in 1,2,4-trichlorobenzene at 150°C, relative to a polystyrene standard. A comparison of refractive index data for Examples 9, 13, and 17 is shown in the figure below. Figure 5 As shown, Figure 5 The refractive index of the cyclic olefin copolymer in Example 9 can reach 1.7014; the visible light transmittance curve of Example 14 is shown below. Figure 6 As shown. Figure 6 This indicates that its transmittance in the visible light region is >93%.

[0122] As shown in Table 1, decreasing the concentration of the cyclic olefin monomer gradually reduces the cyclic olefin monomer insertion rate and the glass transition temperature of the polymer. When the polymerization time is 10 minutes and the concentration of cyclic olefin monomer 1 is 0.4 M, a binary cyclic olefin copolymer with a weight-average molecular weight of 129,000 and a glass transition temperature of 145 °C can be obtained.

[0123] The thermal and optical properties of the copolymers from Examples 9, 10, 11, 13, 14, 17, 18, 21, 22, 23, 27, 29, and Comparative Examples 1 and 2 were tested, as shown in Table 2.

[0124] Table 2

[0125]

[0126]

[0127] Note: All data are based on results from at least two parallel experiments (unless otherwise stated). Activity: in gmol -1 h -1 Unit: M w M w / M n : weight-average molecular weight and polymer dispersibility index, respectively, determined by GPC in 1,2,4-trichlorobenzene at 150°C, relative to polystyrene standards.

[0128] As shown in Table 2, the type and insertion rate of the cyclic olefin monomer affect the optical and thermal properties of the obtained cyclic olefin copolymer. When the insertion rate of cyclic olefin monomer 3 is 31.7 mol%, a binary cyclic olefin copolymer with a weight-average molecular weight of 56,000, a glass transition temperature of 176 °C, and a refractive index of 1.7016 can be obtained.

[0129] As can be seen from the above embodiments, this invention uses cyclic olefin monomers with the structure of Formula II and ethylene or α-olefins as polymerization monomers in an inert solvent, and carries out a polymerization reaction in the presence of a catalyst to obtain cyclic olefin copolymers with the structure of Formula I. This invention uses cyclic olefin monomers with the structure of Formula II and classic metallocene catalysts, and obtains a series of binary cyclic olefin copolymers by adjusting the reaction conditions. The polymerization reaction has high activity, the molecular weight and glass transition temperature of the obtained cyclic olefin copolymers are controllable, and the Formula II structure in the polymer has a certain insertion rate. The cyclic olefin copolymers provided by this invention improve the steric hindrance of the cyclic olefin monomers, resulting in cyclic olefin copolymer resins with high thermal stability. Because R3 and R4 in the Formula II structure are introduced onto the cyclic olefin monomers, the refractive index of the cyclic olefin copolymer resin can be increased. This invention prepares highly active cyclic olefin resins with controllable molecular weight and glass transition temperature by adjusting the reaction conditions. Experimental results show that the cyclic olefin copolymer resin with the structure of formula II has an insertion rate of 14.3 mol%–31.7 mol%, a refractive index of 1.6488–1.7083, a glass transition temperature of 92℃–219℃, a weight-average molecular weight of 56 kg / mol–139 kg / mol, a molecular weight distribution of 1.9–2.5, a visible light transmittance of 91.0%–96.0%, birefringence <0.0009 or no birefringence, and a water absorption rate of <0.01%. The copolymerization reaction exhibits high reactivity, with a reactivity of 1.48–2.81 × 10⁻⁶. 6 g mol -1 h -1 .

[0130] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-refractive-index cyclic olefin copolymer, characterized in that, It has any of the following structures: ； 20≥X:Y≥1,2500≥n≥10。 2. The high refractive index cyclic olefin copolymer according to claim 1, characterized in that, The cyclic olefin copolymer has a refractive index of 1.6488~1.7083, a glass transition temperature of 92℃~219℃, a weight-average molecular weight of 56kg / mol~139kg / mol, and a molecular weight distribution of 1.9~2.

5.

3. A method for preparing the high refractive index cyclic olefin copolymer according to any one of claims 1 to 2, comprising the following steps: In an inert solvent, cyclic olefin monomer 3 and ethylene, propylene or hexene are polymerized in the presence of a metallocene catalyst to obtain cyclic olefin copolymers having any of the following structures; ； 。 4. The preparation method according to claim 3, characterized in that, The metallocene catalyst is selected from non-bridged zirconium dichloride catalysts, isopropylidene-bridged indene zirconium dichloride catalysts, isopropylidene-bridged fluorene zirconium dichloride catalysts, isopropylidene-bridged tert-butylfluorene zirconium dichloride catalysts, diphenyl-bridged fluorene zirconium dichloride catalysts, dimethylsilyl-bridged fluorene zirconium dichloride catalysts, dimethylsilyl-bridged tert-butylamine titanium dichloride catalysts, or dimethylsilyl-bridged fluorene tert-butylamine titanium dichloride catalysts.

5. The preparation method according to claim 3, characterized in that, The molar ratio of the metallocene catalyst to the cyclic olefin monomer 3 is 1:50~2500; The molar ratio of the ethylene, propylene, or hexene to the cycloolefin monomer 3 is (0.5~25):

1.

6. The preparation method according to claim 3, characterized in that, The polymerization reaction is carried out at a temperature of 30~140℃ for a time of 5~240 min.

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