A low-birefringence, high-heat-resistant cyclic olefin polymer and a method for preparing the same

Abstract

The application discloses a low-birefringence high-heat-resistant cycloolefin polymer and a preparation method thereof. The low-birefringence high-heat-resistant cycloolefin polymer has a structural unit shown in formula I. Compared with a commercially available cycloolefin polymer, the cycloolefin polymer disclosed by the application has a higher glass transition temperature, a lower birefringence, and also has high refractive index and high Abbe number.

Description

Technical Field

[0001] This invention relates to the field of polyolefins, specifically to a low birefringence, high heat-resistant cyclic olefin polymer and its preparation method. Background Technology

[0002] In recent years, due to the rapid development of optoelectronic device manufacturing technology, the requirements for optical lenses have gradually increased. The birefringence of a lens is the phenomenon where light passing through it is split into two beams due to differences in the angle of incidence or polarization state, resulting in two beams with different refractive indices. Reducing the birefringence of a lens can significantly reduce image distortion, deformation, or ghosting caused by birefringence, thereby greatly improving image quality.

[0003] Cycloolefin polymers are amorphous, transparent polymers with sterically hindered cyclic alkane structures in their main molecular chain. Zeon Corporation and Nippon Synthetic Rubber Co., Ltd. of Japan have prepared commercially available products such as ZEONEX, ZEONOR, and ARTON by ring-opening metathesis polymerization of cycloolefins followed by hydrogenation of unsaturated bonds. Due to their excellent properties, including good light transmittance, high refractive index, high Abbe number, low birefringence, and good processability, cycloolefin polymers are widely used in optical components for mobile phones, automotive lenses, and security cameras.

[0004] Although cyclic olefin polymers have become ideal materials for small-sized optical lenses, their molecular chain structure still lacks symmetry, making it impossible to balance and counteract the intermolecular forces in the transverse and longitudinal directions, thus preventing them from achieving "zero birefringence." When used as large-sized optical lenses for AR / VR applications, some optical distortion still exists during imaging, and prolonged use can still cause dizziness and eye fatigue. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, the purpose of this invention is to provide a low birefringence, high heat resistance cyclic olefin polymer and its preparation method. The low birefringence, high heat resistance cyclic olefin polymer of this invention, while reducing birefringence and improving heat resistance, also increases the refractive index of the material to a certain extent and possesses the characteristics of high Abbe number and low hygroscopicity.

[0006] To achieve the above technical effects, the present invention adopts the following solution:

[0007] This invention provides a low birefringence, high heat resistance cyclic olefin polymer, which comprises the structural unit shown in Formula I:

[0008]

[0009] In Formula I, R is a cycloalkyl group, preferably selected from one or more of cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornel, adamantyl, etc., and their substituted structures; R1, R2, R3, and R4 are each independently selected from one or more of H, methyl, ethyl, butyl, hexyl, cyclohexyl, phenyl, etc.; R1 and R4 are bonded to each other to form a ring or are not bonded; L is -CH2-CH2- or -CH=CH-; n is an integer from 0 to 2.

[0010] In some preferred embodiments, the low birefringence, high heat-resistant cyclic olefin polymer of the present invention further comprises the structural unit shown in Formula II:

[0011]

[0012] In Formula II, RC is any one of alkyl groups and cycloalkyl groups, preferably C4-C8 alkyl groups or C5-C8 cycloalkyl groups. 15 Any of the cycloalkyl groups, more preferably C4-C8 alkylene groups, C5-C 15 Any one of the groups containing a cyclopentane structure.

[0013] In some specific embodiments, the low birefringence, high heat-resistant cyclic olefin polymer of the present invention, with the total molar amount of the structural units shown in Formula I and Formula II as 100%, wherein the molar content of the structural units shown in Formula I is 5-100 mol%, for example 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 mol%, and the molar content of the structural units shown in Formula II is 0-95 mol%, for example 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95 mol%.

[0014] In some preferred embodiments, the structural unit represented by Formula I of the present invention is prepared by ring-opening polymerization of the compound represented by Formula I-A under the action of a chain transfer agent:

[0015]

[0016] In Equation I-A, the definitions of R1, R2, R3, R4, n, and R are the same as those in Equation I above;

[0017] Preferably, the compound represented by Formula I-A is selected from at least one of compounds M-1, M-2, M-3, M-4, M-5, M-6, and M-7 having the following structures:

[0018]

[0019] In some preferred embodiments, the structural unit shown in Formula II of the present invention is prepared from a cyclic olefin compound shown in Formula II-A:

[0020]

[0021] The definition of RC is the same as the definition of RC in Equation II above;

[0022] Preferably, the cyclic olefin compound represented by Formula II-A is selected from at least one of cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclooctadiene, norbornene, dicyclopentadiene, and tetracyclododecene.

[0023] In this invention, the low birefringence, high heat-resistant cyclic olefin polymer has a number average molecular weight of 5,000-100,000, for example 5,000, 10,000, 20,000, 30,000, 40,000, 50,000, 60,000, 70,000, 80,000, 90,000, and 100,000.

[0024] In this invention, the low birefringence, high heat-resistant cyclic olefin polymer has a double bond molar content of ≤50%, for example 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 1%, preferably ≤1%.

[0025] In this invention, the low birefringence, high heat-resistant cyclic olefin polymer has a glass transition temperature (Tg) of 120-180℃; a stress birefringence (CR) of 1-5nm; a refractive index (nd) of 1.53-1.60; an Abbe number (νd) of 50-60; and a moisture absorption rate ≤0.1%.

[0026] The present invention also provides a method for preparing the above-mentioned low birefringence, high heat resistance cyclic olefin polymer. The method for preparing olefin polymers is well known to those skilled in the art. The following is only an exemplary description and does not constitute any limitation.

[0027] For example, a method for preparing a low birefringence, high heat-resistant cyclic olefin polymer involves two steps: polymerization (1) and hydrogenation (2). Taking the structural unit shown in Formula I as an example, its reaction route is illustrated below:

[0028]

[0029] Specifically, a method for preparing the above-mentioned low birefringence, high heat-resistant cyclic olefin polymer includes the following steps:

[0030] (1) Polymerization: The compound shown in Formula I-A, the optional cyclic olefin compound shown in Formula II-A and the chain transfer agent are mixed and polymerized to obtain a polymer intermediate solution;

[0031] (2) Hydrogenation: The polymer intermediate solution obtained in step (1) is subjected to hydrogenation reaction to obtain the cyclic olefin polymer.

[0032] In this invention, step (1) of the polymerization process specifically involves adding the compound represented by formula I-A, the optional cyclic olefin compound represented by formula II-A, the chain transfer agent, and the ring-opening metathesis polymerization catalyst into a solvent to carry out a solution polymerization reaction.

[0033] Wherein, the molar ratio of the compound represented by formula I-A to the cyclic olefin compound represented by formula II-A is (5-100):(95-0), for example (5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100):(95, 90, 80, 70, 60, 50, 40, 30, 20, 10, 0).

[0034] The chain transfer agent is selected from at least one of olefin compounds containing terminal double bonds, preferably at least one of 1-pentene, 1-hexene, 1-heptene, 1-octene, styrene, vinyl ether, etc.

[0035] Preferably, the molar ratio of the chain transfer agent to the compound represented by Formula I-A and optionally the cyclic olefin compound represented by Formula II-A is 1:(50-2000), for example 1:50, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900, 1:1000, 1:2000.

[0036] Among them, there are many types of ring-opening metathesis polymerization catalysts, and conventional selections in the field can be used. This invention does not have any special requirements for them. For example, they can be any one or at least two combinations of multi-component tungsten-based catalysts, Grubbs series catalysts, and Schrock series catalysts, with Grubbs series catalysts being preferred.

[0037] Preferably, the mass ratio of the ring-opening metathesis polymerization catalyst to the compound represented by Formula I-A and optionally the cyclic olefin compound represented by Formula II-A is 1:10000 to 1000000, for example 1:10000, 1:50000, 1:100000, 1:300000, 1:500000, 1:700000, 1:1000000.

[0038] The solvent is selected from at least one of aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, aromatic hydrocarbon solvents, halogenated aromatic hydrocarbon solvents, and ether solvents.

[0039] Preferably, the aliphatic hydrocarbon solvent is selected from at least one of n-hexane and heptane;

[0040] Preferably, the alicyclic hydrocarbon solvent is selected from at least one of cyclopentane, cyclohexane, methylcyclohexane, and dimethylcyclohexane;

[0041] Preferably, the aromatic hydrocarbon solvent is selected from at least one of benzene, toluene, and xylene;

[0042] Preferably, the halogenated aromatic hydrocarbon solvent is selected from at least one of chlorobenzene and dichlorobenzene;

[0043] Preferably, the ether solvent is selected from at least one of diethyl ether and tetrahydrofuran;

[0044] Preferably, the total mass of the compound represented by Formula I-A and the optional cycloolefin compound represented by Formula II-A accounts for 5-70% of the solvent mass, for example 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70%, preferably 5-50%.

[0045] The solution polymerization reaction is carried out at a temperature of 0–200°C, for example, 0, 10, 30, 50, 80, 100, 130, 150, 180, or 200°C, preferably 50–150°C; and for a time of 1–60 min, for example, 1, 10, 20, 30, 40, 50, or 60 min, preferably 1–30 min.

[0046] In this invention, the hydrogenation process in step (2) specifically involves reacting the polymer intermediate solution obtained in step (1) with hydrogen gas under the action of a hydrogenation catalyst.

[0047] The hydrogenation catalyst can be a homogeneous or heterogeneous catalyst, and any conventional selection in the field is acceptable. This invention does not have any special requirements for it.

[0048] Preferably, the heterogeneous catalyst is selected from at least one of metal-supported silica, metal-supported alumina, metal-supported titanium dioxide, skeletal nickel, palladium on carbon catalyst, etc.; wherein the metal is selected from at least one of nickel, palladium, platinum, rhodium, ruthenium;

[0049] Preferably, the amount of the heterogeneous catalyst added is 0.5 to 10% of the mass of the polymer intermediate solution obtained in step (1), for example, 0.5, 1, 3, 5, 7, 9, 10%;

[0050] Preferably, the homogeneous catalyst is selected from at least one of soluble complexes of metals such as nickel, titanium, palladium, platinum, rhodium, and ruthenium, such as the Ziegler hydrogenation catalyst composed of nickel salt-alkylaluminum, the titanium locene-alkyllithium hydrogenation catalyst, and the Ru(X)Cl(CO)L2 type complex catalyst.

[0051] Preferably, the amount of homogeneous catalyst added is 0.001 to 10% of the mass of the polymer intermediate solution obtained in step (1), for example, 0.001, 0.01, 0.1, 0.5, 1, 3, 5, 7, 9, 10%.

[0052] The hydrogenation reaction is carried out under high temperature and high pressure.

[0053] The hydrogenation temperature is 80–200°C, for example, 80, 100, 130, 150, 180, 200°C;

[0054] The amount of hydrogen fed is determined by the charging pressure. The charging pressure is controlled to be 1-7 MPa of the reaction pressure, for example, 1, 2, 3, 4, 5, 6, 7 MPa.

[0055] Preferably, the hydrogenation reaction endpoint is reached when the molar content of double bonds in the obtained low birefringence, high heat-resistant cyclic olefin polymer is ≤50%, for example 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 1%, preferably ≤1%.

[0056] Preferably, step (1) of the present invention further includes terminating the reaction, and step (2) further includes post-treatment processes such as acidification, flocculation, washing, and drying, all of which are conventional operations in the field and are not specifically limited by the present invention.

[0057] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0058] The low birefringence, high heat-resistant cyclic olefin polymer of this invention introduces a symmetrical alicyclic structure, which improves the symmetry of the molecular chain to balance and counteract the intermolecular forces in the transverse and longitudinal directions, further reducing the birefringence of the material. The symmetrical rigid alicyclic structure can also further improve the heat resistance and refractive index of the material. At the same time, this invention does not introduce additional unsaturated bonds and polar groups, thus maintaining the material's high Abbe number and low hygroscopicity. Detailed Implementation

[0059] To better understand the technical solution of the present invention, the content of the present invention will be further described below with reference to the following specific embodiments, but the content of the present invention is not limited to the following embodiments.

[0060] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0061] All raw materials used in the examples are conventional raw materials in the art, and the purity specifications used are analytical grade or chemically pure.

[0062] The source information of the raw materials used in the following examples is as follows. Unless otherwise specified, all other raw materials are conventional in the art, and the purity specifications used are analytical grade or chemically pure:

[0063] High-purity hydrogen: 99.999%, Dalian Guangming Special Gases Co., Ltd.;

[0064] Dicyclopentadiene: 98% (GC), Sigma-Aldrich;

[0065] Cyclooctene: 95% (GC), Bailingwei Technology;

[0066] 1-Hexene: 99%, Sigma-Aldrich;

[0067] 1-Octenene: 99%, Bailingwei Technology;

[0068] Cyclopentadienyllithium: 97%, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0069] Norbornene: 98%, TCI;

[0070] Tetracyclododecene: 98%, TCI;

[0071] Chloroadamane: 98%, Shanghai Aladdin;

[0072] Chlorocyclopentane: 98%, Shanghai Aladdin;

[0073] Chlorocyclohexane: 99%, Shanghai Aladdin;

[0074] Cyclohexene: 98%, Shanghai Aladdin;

[0075] Vinylcyclohexane: 98%, Shanghai Aladdin; Grubbs 2nd generation catalyst: 99.95%, Shanghai Aladdin;

[0076] Supported nickel catalyst: Ni@Al2O3, Alfa;

[0077] Nickel acetylacetone: 95%, Shanghai Aladdin;

[0078] Triisobutylaluminum: 1.0M n-hexane solution, Shanghai Aladdin.

[0079] The performance test parameters and corresponding test methods used in the various embodiments of the present invention are as follows:

[0080] The structures of the compounds and polymers synthesized in this invention were determined by a Bruker ARX-400 nuclear magnetic resonance spectrometer, using deuterated chloroform (CDCl3), deuterated benzene (C6D6), and deuterated 1,1,2,2-tetrachloroethane (C2D2Cl4) as solvents, at room temperature or 90°C.

[0081] The molecular weight and molecular weight distribution of the polymer synthesized in this invention were obtained by testing with a PL-GPC220 at 150°C using three PLgel 10μm MIXED-B separation columns in series, with 1,2,4-trichlorobenzene as the solvent.

[0082] The thermal properties (glass transition temperature Tg) of the polymer were measured by a TA Q2000 differential scanning calorimeter in accordance with ISO 11357.

[0083] The refractive index (nd) and Abbe number (vd) of the polymer were measured using an Atago DR-M4 refractometer according to ASTM D542 standard; the birefringence (CR) of the polymer was measured using a Pla WPA-200. The heat distortion temperature (HDT) of the polymer was measured according to ASTM D648 standard.

[0084] The water absorption rate of the polymer was determined by the swelling method. After drying the prepared sample, it was immersed in water at 25°C for 48 hours, then taken out and weighed again to calculate the percentage increase in weight.

[0085] Specific Implementation

[0087] (I) Monomer Preparation:

[0088] Synthesis example-1

[0089]

[0090] In a glove box, 2.1 mol of cyclopentadienyllithium and 1000 ml of n-hexane were added to a 2 L flask and dispersed evenly. Then, 2.1 mol of chlorocyclopentane was added dropwise to the flask. After the addition was complete, the mixture was stirred for 30 min, filtered, and the filtrate was dried to obtain cyclopentylcyclopentadiene. ¹H NMR (400 MHz, CDCl₃): δ = 6.21 (2H), δ = 6.08 (2H), δ = 2.86 (1H), δ = 1.94–1.87 (4H); δ = 1.58 (3H); δ = 1.11 (2H).

[0091] Synthesis example-2

[0092]

[0093] The preparation of cyclohexanecyclopentadiene is the same as that of cyclopentylcyclopentadiene, except that chlorocyclohexane is used instead of chlorocyclopentane. ¹H NMR (400 MHz, CDCl₃): δ = 6.21 (2H), δ = 6.08 (2H), δ = 2.89 (1H), δ = 1.95 (1H); δ = 1.78 (1H); δ = 1.53 (2H); δ = 1.30–1.23 (5H); δ = 1.19 (1H).

[0094] Synthesis example-3

[0095]

[0096] The preparation of adamantylcyclopentadiene is the same as that of cyclopentylcyclopentadiene, except that chloroadamantane is used instead of chlorocyclopentane. ¹H NMR (400 MHz, CDCl₃): δ = 6.20 (2H), δ = 6.06 (2H), δ = 2.80 (1H), δ = 2.01–1.95 (3H); δ = 1.80–1.76 (3H); δ = 1.58 (2H); δ = 1.46 (1H); δ = 1.38–1.39 (3H); δ = 1.01–1.23 (3H).

[0097] Monomer Synthesis Example-1

[0098]

[0099] In a 2L stainless steel high-pressure reactor, 1.9 mol of cyclopentylcyclopentadiene was added. The atmosphere inside the reactor was replaced with nitrogen, and then replaced with an ethylene atmosphere. The ethylene was pressurized to 3 MPa, stirring was started, and the reactor was heated to 180℃. The ethylene pressure was then increased to 5 MPa, and the reaction was carried out for 6 hours. After the reaction was completed, the reactor was cooled to room temperature, and the reactants were purified by column chromatography (ethyl acetate / petroleum ether = 1 / 10) to obtain the corresponding monomers. ¹H NMR (400MHz, CDCl₃): δ=5.83(2H), δ=2.66(2H), δ=1.94–1.82(6H), δ=1.57–1.54(4H); δ=1.35(2H); δ=1.08(2H).

[0100] Monomer Synthesis Example-2

[0101]

[0102] The preparation of monomer M-2 was the same as that of monomer M-1, except that cyclohexylcyclopentadiene was used instead of cyclopentylcyclopentadiene. ¹H NMR (400MHz, CDCl₃): δ=5.83(2H), δ=2.66(2H), δ=2.34(1H), δ=1.85-1.78(2H); δ=1.57-1.50(4H); δ=1.35-1.23(7H); δ=1.17(2H).

[0103] Monomer Synthesis Example-3

[0104]

[0105] The preparation of monomer M-3 was the same as that of monomer M-1, except that adamantylcyclopentadiene was used instead of cyclopentylcyclopentadiene. ¹H NMR (400 MHz, CDCl₃): δ = 5.86 (2H), δ = 2.78–2.75 (2H), δ = 2.01–1.94 (3H), δ = 1.80–1.74 (3H); δ = 1.58–1.55 (4H); δ = 1.44 (2H); δ = 1.37–1.36 (5H); δ = 1.29–0.83 (5H).

[0106] Monomer Synthesis Example-4

[0107]

[0108] In a 2L stainless steel high-pressure reactor, 1.9 mol of cyclohexylcyclopentadiene and 3.5 mol of vinylcyclohexane were added, the atmosphere inside the reactor was replaced with nitrogen, stirring was started, and the mixture was heated to 180℃ for 6 hours. After the reaction was completed, the reactor was cooled to room temperature, and the reactants were purified by column chromatography (ethyl acetate / petroleum ether = 1 / 10) to obtain the corresponding monomers.

[0109] 1H NMR (400MHz, CDCl3): δ=5.43(2H), δ=2.36(1H), δ=2.02-1.97(1H), δ=1.68-1.12(26H).

[0110] Monomer Synthesis Example-5

[0111]

[0112] The synthesis was consistent with that of M-4, except that cyclohexene was used instead of vinylcyclohexane. ¹H NMR (400MHz, CDCl₃): δ=5.43(2H), δ=2.36-2.30(3H), δ=2.02(2H), δ=1.78-1.71(2H); δ=1.50(4H); δ=1.34-1.23(7H); δ=1.17-1.02(6H).

[0113] Monomer Synthesis Example-6

[0114]

[0115] The synthesis was consistent with that of M-4, except that adamantylcyclopentadiene replaced cyclohexylcyclopentadiene, and cyclohexene replaced vinylcyclohexane. ¹H NMR (400MHz, CDCl₃): δ=5.43(2H), δ=2.44-2.41(2H), δ=2.03-1.94(5H), δ=1.80-1.74(3H); δ=1.56-1.53(5H); δ=1.44-1.23(8H); δ=1.09-0.83(7H).

[0116] Monomer Synthesis Example-7

[0117]

[0118] The synthesis was consistent with that of M-6, except that norbornene was used instead of cyclohexene. ¹H NMR (400MHz, CDCl₃): δ=5.50(2H), δ=2.50-2.47(2H), δ=2.05-1.71(10H), δ=1.61-1.46(3H); δ=1.44-0.77(15H).

[0119] (II) Polymer Preparation

[0120] Example 1

[0121] HPM-1 preparation

[0122]

[0123] (1-1) Preparation of ring-opening polymers (PM-1)

[0124] In a glove box, 2.12 g of dicyclopentadiene, 6.42 g of tetracyclododecene, and 3.90 g of monomer M-1 were dissolved in 44 g of xylene, followed by the addition of 50.2 mg of 1-hexene. The solution was then added to a 250 ml flask equipped with a magnetic stir bar, and stirring and heating were initiated. When the temperature reached 40 °C, 0.3 mg of Grubbs' second-generation catalyst was added to the flask to begin polymerization. After 30 min of polymerization, 1 g of ethanol was added to terminate the polymerization at the active site. The total volume of the reaction solution was 50 g. The weight-average molecular weight (Mw) of the obtained ring-opening polymer was 1.3 × 10⁻⁶. 4 The conversion rate of monomer to polymer is >99%.

[0125] (1-2) Hydrogenation of ring-opening polymers (HPM-1)

[0126] Weigh 25.8 mg (100 μmol) of nickel acetylacetonate in a glove box and disperse it in 5 g of xylene. Take 0.4 g (0.5 mmol) of triisobutylaluminum and inject it into the nickel acetylacetonate. React for 2 min to prepare a hydrogenation catalyst.

[0127] Weigh 40g of the ring-opening polymer reaction solution from (1-1), dilute it with 40g of xylene, and transfer it to a pre-dried stainless steel reactor. Replace the reactor atmosphere three times sequentially with nitrogen and then with hydrogen. Inject 3g of the prepared hydrogenation catalyst into the reactor, pressurize it to 4MPa with hydrogen, start stirring, and heat to 80℃. After 4 hours of reaction, the hydrogenation reaction endpoint is reached when the double bond content in the product decreases to 1%, yielding the corresponding hydrogenated polymer solution. After cooling, centrifuge the solution, pour the supernatant into acidified ethanol, and wash three times for flocculation. Wash the precipitated polymer three times with deionized water and dry it in a vacuum oven. The resulting hydrogenated polymer, namely polymer (HPM-1), has a weight-average molecular weight (Mw) of 1.5 × 10⁻⁶. 4 The residual amount of double bonds is less than 1%.

[0128] (1-3) Preparation of hydrogenated polymer membranes

[0129] Take 2g of the cyclic olefin polymer obtained in step (1-2) and dissolve it in 10ml of xylene. Pour the resulting polymer solution into a clean mold and evaporate the solvent to obtain the corresponding polymer film.

[0130] The glass transition temperature (Tg), stress birefringence (CR), refractive index (nd), and Abbe number (νd) of the cyclic olefin polymer HPM-1 obtained by the aforementioned method are shown in Table 1.

[0131] Example 2

[0132] HPM-2 preparation

[0133]

[0134] (2-1) Preparation of ring-opening polymers (PM-2)

[0135] In a glove box, 0.79 g of dicyclopentadiene, 3.53 g of tetracyclododecene, and 2.12 g of monomer M-2 were dissolved in 44 g of cyclohexane. Then, 26.8 mg of 1-hexene was added. The solution was poured into a 250 ml flask equipped with a magnetic stir bar, and stirring and heating were started. When the temperature reached 40 °C, 0.3 mg of Grubbs second-generation catalyst was added to the flask to begin polymerization. After 30 min of polymerization, 1 g of ethanol was added to terminate the polymerization at the active site. The total volume of the reaction solution was 50 g. The weight-average molecular weight (Mw) of the obtained ring-opening polymer was 2.7 × 10⁻⁶. 4The conversion rate of monomer to polymer is >99%.

[0136] (2-2) Hydrogenation of ring-opening polymers (HPM-2)

[0137] Weigh 40g of the ring-opening polymer reaction solution from (2-1) and transfer it to a pre-dried stainless steel reactor. Add 2g of supported nickel catalyst to the reactor, seal the reactor, and then purge the atmosphere inside the reactor three times sequentially with nitrogen and hydrogen, respectively. Pressurize the reactor to 4MPa with hydrogen, start stirring, and heat to 130℃. After 4 hours of reaction, the hydrogenation reaction endpoint is reached when the double bond content in the product decreases to 1%, yielding the corresponding hydrogenated polymer solution. After cooling, centrifuge the solution, pour the supernatant into acidified ethanol, and wash three times for flocculation. Wash the precipitated polymer three times with deionized water and dry it in a vacuum oven. The resulting hydrogenated polymer, namely polymer (HPM-2), has a weight-average molecular weight Mw of 2.8 × 10⁻⁶. 4 The residual amount of double bonds is less than 1%.

[0138] (2-3) Preparation of hydrogenated polymer membranes

[0139] Take 2g of the hydrogenated polymer obtained in step (2-2) and dissolve it in 10ml of xylene. Pour the resulting polymer solution into a clean mold and evaporate the solvent to obtain the corresponding hydrogenated polymer film.

[0140] The glass transition temperature (Tg), stress birefringence (CR), refractive index (nd), and Abbe number (νd) of the hydrogenated polymer HPM-2 obtained by the above method are shown in Table 1.

[0141] Example 3

[0142] HPM-3 preparation

[0143]

[0144] (3-1) Preparation of ring-opening polymers (PM-3)

[0145] In a glove box, 2.16 g of dicyclopentadiene, 2.56 g of tetracyclododecene, and 1.83 g of monomer M-3 were dissolved in 33 g of xylene, followed by the addition of 67.2 mg of 1-hexene. The solution was then added to a 250 ml flask equipped with a magnetic stir bar, and stirring and heating were initiated. When the temperature reached 40 °C, 0.3 mg of Grubbs second-generation catalyst was added to the flask to begin polymerization. After 30 min of polymerization, 1 g of ethanol was added to terminate the polymerization at the active site. The total volume of the reaction solution was 40 g. The weight-average molecular weight (Mw) of the obtained ring-opening polymer was 1.1 × 10⁻⁶. 4 The conversion rate of monomer to polymer is >99%.

[0146] (3-2) Hydrogenation of ring-opening polymers (HPM-3)

[0147] Weigh 25.8 mg (100 μmol) of nickel acetylacetonate in a glove box and disperse it in 5 g of xylene. Take 0.4 g (0.5 mmol) of triisobutylaluminum and inject it into the nickel acetylacetonate. React for 2 min to prepare a hydrogenation catalyst.

[0148] Weigh 30g of the ring-opening polymer reaction solution from (3-1), dilute it with 10g of xylene, and transfer it to a pre-dried stainless steel reactor. Replace the reactor atmosphere three times sequentially with nitrogen and then with hydrogen. Inject 1g of the prepared hydrogenation catalyst into the reactor, pressurize it to 4MPa with hydrogen, start stirring, and heat to 80℃. After 4 hours of reaction, the hydrogenation reaction endpoint is reached when the double bond content in the product decreases to 1%, yielding the corresponding hydrogenated polymer solution. After cooling, pour the reaction solution into acidified ethanol, wash it three times for flocculation, wash the precipitated polymer three times with deionized water, and dry it in a vacuum oven. The resulting hydrogenated polymer, namely polymer (HPM-3), has a weight-average molecular weight Mw of 1.1 × 10⁻⁶. 4 The residual amount of double bonds is less than 1%.

[0149] (3-3) Preparation of hydrogenated polymer membranes

[0150] Take 2g of the hydrogenated polymer obtained in step (3-2) and dissolve it in 10ml of xylene. Pour the resulting polymer solution into a clean mold and evaporate the solvent to obtain the corresponding hydrogenated polymer film.

[0151] The glass transition temperature (Tg), stress birefringence (CR), refractive index (nd), and Abbe number (νd) of the hydrogenated polymer HPM-3 obtained by the above method are shown in Table 1.

[0152] Example 4

[0153] HPM-4 preparation

[0154]

[0155] (4-1) Preparation of ring-opening polymers (PM-4)

[0156] In a glove box, 0.19 g of norbornene, 0.32 g of tetracyclododecene, and 9.30 g of monomer M-4 were dissolved in 32 g of xylene. Then, 16.8 mg of 1-hexene was added. The solution was poured into a 250 ml flask equipped with a magnetic stir bar, and stirring and heating were started. When the temperature reached 40 °C, 0.3 mg of Grubbs second-generation catalyst was added to the flask to begin polymerization. After 30 min of polymerization, 1 g of ethanol was added to terminate the polymerization at the active site. The total volume of the reaction solution was 40 g. The weight-average molecular weight (Mw) of the obtained ring-opening polymer was 5.4 × 10⁻⁶. 4 The conversion rate of monomer to polymer is >99%.

[0157] (4-2) Hydrogenation of ring-opening polymers (HPM-4)

[0158] Weigh 25.8 μmol (100 μmol) of nickel acetylacetonate in a glove box and disperse it in 5 g of xylene. Take 0.4 g (0.5 mmol) of triisobutylaluminum and inject it into the nickel acetylacetonate. React for 2 min to prepare a hydrogenation catalyst.

[0159] Weigh 20g of the ring-opening polymer reaction solution from (4-1), dilute it with 20g of xylene, and transfer it to a pre-dried stainless steel reactor. Replace the reactor atmosphere three times sequentially with nitrogen and then with hydrogen. Inject 2g of the prepared hydrogenation catalyst into the reactor, pressurize it to 4MPa with hydrogen, start stirring, and heat to 80℃. After 4 hours of reaction, the hydrogenation reaction endpoint is reached when the double bond content in the product decreases to 1%, yielding the corresponding hydrogenated polymer solution. After cooling, pour the reaction solution into acidified ethanol, wash it three times for flocculation, wash the precipitated polymer three times with deionized water, and dry it in a vacuum oven. The resulting hydrogenated polymer, namely polymer (HPM-4), has a weight-average molecular weight Mw of 5.5 × 10⁻⁶. 4 The residual amount of double bonds is less than 1%.

[0160] (4-3) Preparation of hydrogenated polymer membranes

[0161] Take 2g of the hydrogenated polymer obtained in step (4-2) and dissolve it in 10ml of xylene. Pour the resulting polymer solution into a clean mold and evaporate the solvent to obtain the corresponding hydrogenated polymer film.

[0162] The glass transition temperature (Tg), stress birefringence (CR), refractive index (nd), and Abbe number (νd) of the hydrogenated polymer HPM-4 obtained by the above method are shown in Table 1.

[0163] Example 5

[0164] HPM-5 preparation

[0165]

[0166] (5-1) Preparation of ring-opening polymers (PM-5)

[0167] In a glove box, 2.11 g of dicyclopentadiene, 2.24 g of tetracyclododecene, and 2.51 g of monomer M-5 were dissolved in 33 g of cyclohexane. Then, 16.8 mg of 1-hexene was added. The solution was poured into a 250 ml flask equipped with a magnetic stir bar, and stirring and heating were started. When the temperature reached 40 °C, 0.3 mg (4 μmol) of Grubbs second-generation catalyst was added to the flask to begin polymerization. After 30 min of polymerization, 1 g of ethanol was added to terminate the polymerization at the active site. The total volume of the reaction solution was 40 g. The weight-average molecular weight (Mw) of the obtained ring-opening polymer was 4.3 × 10⁻⁶. 4 The conversion rate of monomer to polymer is >99%.

[0168] (5-2) Hydrogenation of ring-opening polymers (HPM-5)

[0169] Weigh 25.8 μmol (100 μmol) of nickel acetylacetone in a glove box and disperse it in 5 g of decahydronaphthalene. Take 0.4 g (0.5 mmol) of triisobutylaluminum and inject it into the nickel acetylacetone. React for 2 min to prepare a hydrogenation catalyst.

[0170] Weigh 20g of the ring-opening polymer reaction solution from (5-1), dilute it with 20g of cyclohexane, and transfer it to a pre-dried stainless steel reactor. Replace the reactor atmosphere three times sequentially with nitrogen and then with hydrogen. Inject 2g of the prepared hydrogenation catalyst into the reactor, pressurize it to 4MPa with hydrogen, start stirring, and heat to 80℃. After 4 hours of reaction, the hydrogenation reaction endpoint is reached when the double bond content in the product decreases to 1%, yielding the corresponding hydrogenated polymer solution. After cooling, pour the reaction solution into acidified ethanol, wash it three times for flocculation, wash the precipitated polymer three times with deionized water, and dry it in a vacuum oven. The resulting hydrogenated polymer, namely polymer (HPM-5), has a weight-average molecular weight (Mw) of 4.5 × 10⁻⁶. 4 The residual amount of double bonds is less than 1%.

[0171] (5-3) Preparation of hydrogenated polymer membranes

[0172] Take 2g of the hydrogenated polymer obtained in step (5-2) and dissolve it in 10ml of xylene. Pour the resulting polymer solution into a clean mold and evaporate the solvent to obtain the corresponding hydrogenated polymer film.

[0173] The results of glass transition temperature (Tg), stress birefringence (CR), refractive index (nd), and Abbe number (νd) of the hydrogenated polymer HPM-5 obtained by the above method are shown in Table 1.

[0174] Example 6

[0175] HPM-6 preparation

[0176]

[0177] (6-1) Preparation of ring-opening polymers (PM-5)

[0178] In a glove box, 2.64 g of dicyclopentadiene, 2.56 g of tetracyclododecene, and 1.13 g of monomer M-6 were dissolved in 53 g of cyclohexane. Then, 1.8 mg of 1-hexene was added. The solution was poured into a 250 ml flask equipped with a magnetic stir bar, and stirring and heating were started. When the temperature reached 40 °C, 0.3 mg (4 μmol) of Grubbs second-generation catalyst was added to the flask to begin polymerization. After 30 min of polymerization, 1 g of ethanol was added to terminate the polymerization at the active site. The total volume of the reaction solution was 60 g. The weight-average molecular weight (Mw) of the obtained ring-opening polymer was 41.8 × 10⁻⁶. 4 The conversion rate of monomer to polymer is >99%.

[0179] (6-2) Hydrogenation of ring-opening polymers (HPM-5)

[0180] Weigh 25.8 μmol (100 μmol) of nickel acetylacetone in a glove box and disperse it in 5 g of decahydronaphthalene. Take 0.4 g (0.5 mmol) of triisobutylaluminum and inject it into the nickel acetylacetone. React for 2 min to prepare a hydrogenation catalyst.

[0181] Weigh 20g of the ring-opening polymer reaction solution from (6-1), dilute it with 20g of cyclohexane, and transfer it to a pre-dried stainless steel reactor. Replace the reactor atmosphere three times sequentially with nitrogen and then with hydrogen. Inject 2g of the prepared hydrogenation catalyst into the reactor, pressurize it to 4MPa with hydrogen, start stirring, and heat to 80℃. After 4 hours of reaction, the hydrogenation reaction endpoint is reached when the double bond content in the product decreases to 1%, yielding the corresponding hydrogenated polymer solution. After cooling, pour the reaction solution into acidified ethanol, wash it three times for flocculation, wash the precipitated polymer three times with deionized water, and dry it in a vacuum oven. The resulting hydrogenated polymer, namely polymer (HPM-6), has a weight-average molecular weight (Mw) of 45.8 × 10⁻⁶. 4 The residual amount of double bonds is less than 1%.

[0182] (6-3) Preparation of hydrogenated polymer membranes

[0183] Take 2g of the hydrogenated polymer obtained in step (6-2) and dissolve it in 10ml of xylene. Pour the resulting polymer solution into a clean mold and evaporate the solvent to obtain the corresponding hydrogenated polymer film.

[0184] The results of glass transition temperature (Tg), stress birefringence (CR), refractive index (nd), and Abbe number (νd) of the hydrogenated polymer HPM-6 obtained by the above method are shown in Table 1.

[0185] Example 7

[0186] HPM-7 preparation

[0187]

[0188] (7-1) Preparation of ring-opening polymers (PM-7)

[0189] In a glove box, 2.64 g of dicyclopentadiene, 2.89 g of tetracyclododecene, and 0.59 g of monomer M-7 were dissolved in 30 g of cyclohexane. Then, 57.1 mg of 1-hexene was added. The solution was poured into a 250 ml flask equipped with a magnetic stir bar, and stirring and heating were started. When the temperature reached 40 °C, 0.3 mg (4 μmol) of Grubbs second-generation catalyst was added to the flask to begin polymerization. After 30 min of polymerization, 1 g of ethanol was added to terminate the polymerization at the active site. The total volume of the reaction solution was 40 g. The weight-average molecular weight (Mw) of the obtained ring-opening polymer was 1.3 × 10⁻⁶. 4 The conversion rate of monomer to polymer is >99%.

[0190] (7-2) Hydrogenation of ring-opening polymers (HPM-7)

[0191] Weigh 25.8 μmol (100 μmol) of nickel acetylacetone in a glove box and disperse it in 5 g of decahydronaphthalene. Take 0.4 g (0.5 mmol) of triisobutylaluminum and inject it into the nickel acetylacetone. React for 2 min to prepare a hydrogenation catalyst.

[0192] Weigh 20g of the ring-opening polymer reaction solution from (5-1), dilute it with 20g of cyclohexane, and transfer it to a pre-dried stainless steel reactor. Replace the reactor atmosphere three times sequentially with nitrogen and then with hydrogen. Inject 2g of the prepared hydrogenation catalyst into the reactor, pressurize it to 4MPa with hydrogen, start stirring, and heat to 80℃. After 4 hours of reaction, the hydrogenation reaction endpoint is reached when the double bond content in the product decreases to 1%, yielding the corresponding hydrogenated polymer solution. After cooling, pour the reaction solution into acidified ethanol, wash it three times for flocculation, wash the precipitated polymer three times with deionized water, and dry it in a vacuum oven. The resulting hydrogenated polymer, namely polymer (HPM-7), has a weight-average molecular weight (Mw) of 1.5 × 10⁻⁶. 4 The residual amount of double bonds is less than 1%.

[0193] (7-3) Preparation of hydrogenated polymer membranes

[0194] Take 2g of the hydrogenated polymer obtained in step (7-2) and dissolve it in 10ml of xylene. Pour the resulting polymer solution into a clean mold and evaporate the solvent to obtain the corresponding hydrogenated polymer film.

[0195] The results of glass transition temperature (Tg), stress birefringence (CR), refractive index (nd), and Abbe number (νd) of the hydrogenated polymer HPM-7 obtained by the above method are shown in Table 1.

[0196] Comparative Example 1

[0197] The preparation method of Example 1 was followed, except that monomer M-1 was replaced with an equal amount of norbornene, while other operations and parameters remained unchanged. The polymer was obtained and the performance test results are shown in Table 1.

[0198] Comparative Example 2

[0199] The preparation method of Example 3 was used, except that monomer M-3 was replaced with an equal amount of norbornene, while other operations and parameters remained unchanged. The polymer was obtained and the performance test results are shown in Table 1.

[0200] Comparative Example 3

[0201] The preparation method of Example 5 was followed, except that monomer M-5 was replaced with an equal amount of dicyclopentadiene, while other operations and parameters remained unchanged. The polymer was obtained, and the performance test results are shown in Table 1.

[0202] In addition, the performance of three cyclic olefin polymers, namely ZEONEX K26R and ZEONEX 690R from ZEON and ARTON F4520 from JSR, which are currently the mainstream commercial products on the market, was also tested under the same conditions. The results are shown in Table 1.

[0203] Table 1. Properties of polymers prepared in the embodiments and comparative examples of the present invention and properties of commercially available cyclic olefin polymers.

[0204]

[0205] Compared to mainstream commercially available cyclic olefin polymers and comparative examples, the cyclic olefin polymers provided by this invention exhibit significantly reduced birefringence, significantly increased glass transition temperature and heat distortion temperature, while also maintaining refractive index, high Abbe number, and low hygroscopicity. According to this invention, compositions that can be advantageously used as materials for optical elements, and molded articles that can be advantageously used as optical elements, are provided.

Claims

1. A low birefringence, high heat-resistant cyclic olefin polymer, characterized in that, It includes the structural unit shown in Equation I below: Formula I In Formula I, R is selected from one of cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and adamantyl; R1, R2, R3, and R4 are each independently selected from one of H, methyl, ethyl, butyl, hexyl, and cyclohexyl, and R1 and R4 are bonded to each other to form a ring or are not bonded; L is -CH2-CH2- or -CH=CH-; n is an integer from 0 to 2; It also includes the structural unit shown in Equation II: Formula II In Equation II, RC is C5-C 15 It contains cyclopentane-containing structural groups.

2. The low birefringence, high heat-resistant cyclic olefin polymer according to claim 1, characterized in that, Taking the total molar amount of the structural units shown in Formula I and Formula II as 100%, the molar content of the structural units shown in Formula I is 5-100 mol, the molar content of the structural units shown in Formula II is 0-95 mol, the molar content of the structural units shown in Formula I does not include 100 mol, and the molar content of the structural units shown in Formula II does not include 0 mol.

3. The low birefringence, high heat-resistant cyclic olefin polymer according to claim 1, characterized in that, The structural unit shown in Formula I is prepared from the compound shown in Formula I-A: Formula I-A In Equation I-A, the definitions of R, R1, R2, R3, and n are the same as those in Equation I above.

4. The low birefringence, high heat-resistant cyclic olefin polymer according to claim 3, characterized in that, The compound represented by Formula I-A is selected from at least one of the following compounds: M-1, M-2, M-3, M-4, M-5, M-6, and M-7, having the following structures: 。 5. The low birefringence, high heat-resistant cyclic olefin polymer according to claim 3, characterized in that, The structural unit shown in Formula II is prepared from the cyclic olefin compound shown in Formula II-A: Formula II-A The definition of RC is the same as that of RC in Equation II above.

6. The low birefringence, high heat-resistant cyclic olefin polymer according to claim 5, characterized in that, The cyclic olefin compounds represented by Formula II-A are selected from at least one of norbornene, dicyclopentadiene, and tetracyclododecene.

7. The low birefringence, high heat-resistant cyclic olefin polymer according to any one of claims 1-6, characterized in that, The number average molecular weight is 5,000-100,000; and / or, the molar content of double bonds is ≤50%.

8. The low birefringence, high heat-resistant cyclic olefin polymer according to claim 7, characterized in that, The molar content of double bonds is ≤1%.

9. A method for preparing a low birefringence, high heat-resistant cyclic olefin polymer according to any one of claims 5-8, characterized in that the step... include: (1) Polymerization: The compound shown in Formula I-A is mixed with the cyclic olefin compound shown in Formula II-A and the chain transfer agent to carry out a polymerization reaction to obtain a polymer intermediate; (2) Hydrogenation: The polymer intermediate obtained in step (1) is subjected to hydrogenation reaction to obtain the low birefringence, high heat resistance cyclic olefin polymer.

10. The preparation method according to claim 9, characterized in that, Step (1) The polymerization process is as follows: the compound shown in Formula I-A, the cyclic olefin compound shown in Formula II-A, the chain transfer agent, and the ring-opening metathesis polymerization catalyst are added to the solvent to carry out solution polymerization reaction.

11. The preparation method according to claim 10, characterized in that, The molar ratio of the compound shown in Formula I-A to the cyclic olefin compound shown in Formula II-A is (5-100):(95-0), wherein the molar ratio of the compound shown in Formula I-A to the cyclic olefin compound shown in Formula II-A does not include 100:

0.

12. The preparation method according to claim 10, characterized in that, The chain transfer agent is selected from at least one of terminal double-bond olefin compounds.

13. The preparation method according to claim 12, characterized in that, The chain transfer agent is selected from at least one of 1-pentene, 1-hexene, 1-heptene, 1-octene, styrene, and vinyl ether.

14. The preparation method according to claim 13, characterized in that, The molar ratio of the chain transfer agent to the compound shown in Formula I-A and the cyclic olefin compound shown in Formula II-A is 1:(50-2000).

15. The preparation method according to claim 10, characterized in that, The ring-opening metasomatic polymerization catalyst is any one or a combination of at least two of the following: multi-component tungsten-based catalysts, Grubbs series catalysts, and Schrock series catalysts.

16. The preparation method according to claim 15, characterized in that, The mass ratio of the ring-opening metathesis polymerization catalyst to the compound shown in Formula I-A and the cyclic olefin compound shown in Formula II-A is 1:10000 to 1000000.

17. The preparation method according to claim 10, characterized in that, The solvent is selected from at least one of aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, aromatic hydrocarbon solvents, halogenated aromatic hydrocarbon solvents, and ether solvents. Specifically, the aliphatic hydrocarbon solvent is selected from at least one of n-hexane and heptane; the alicyclic hydrocarbon solvent is selected from at least one of cyclopentane, cyclohexane, methylcyclohexane, and dimethylcyclohexane; the aromatic hydrocarbon solvent is selected from at least one of benzene, toluene, and xylene; the halogenated aromatic hydrocarbon solvent is selected from at least one of chlorobenzene and dichlorobenzene; and the ether solvent is selected from at least one of diethyl ether and tetrahydrofuran.

18. The preparation method according to claim 17, characterized in that, The total mass of the compounds represented by Formula I-A and the cyclic olefin compounds represented by Formula II-A accounts for 5% to 70% of the solvent mass.

19. The preparation method according to claim 18, characterized in that, The total mass of the compounds represented by Formula I-A and the cyclic olefin compounds represented by Formula II-A accounts for 5% to 50% of the solvent mass.

20. The preparation method according to claim 10, characterized in that, The solution polymerization reaction is carried out at a temperature of 0-200℃ for a time of 1-60 min.

21. The preparation method according to claim 20, characterized in that, The solution polymerization reaction is carried out at a temperature of 50-150℃ for a time of 1-30 minutes.

22. The preparation method according to claim 9, characterized in that, The hydrogenation process in step (2) is as follows: the polymer intermediate obtained in step (1) is hydrogenated with hydrogen under the action of a hydrogenation catalyst.

23. The preparation method according to claim 22, characterized in that, The hydrogenation catalyst in step (2) includes a homogeneous or heterogeneous catalyst. The heterogeneous catalyst is selected from at least one of metal-supported silica, metal-supported alumina, metal-supported titanium oxide, skeletal nickel, and palladium on carbon catalyst. The metal is selected from at least one of nickel, palladium, platinum, rhodium, and ruthenium. The homogeneous catalyst is selected from at least one of soluble complexes of nickel, titanium, palladium, platinum, rhodium, and ruthenium metals.

24. The preparation method according to claim 23, characterized in that, The amount of the heterogeneous catalyst added is 0.5 to 10% of the mass of the polymer intermediate solution obtained in step (1); And / or, the amount of the homogeneous catalyst added is 0.001 to 10% of the mass of the polymer intermediate solution obtained in step (1).

25. The preparation method according to claim 22, characterized in that, The hydrogenation reaction is carried out at a temperature of 80–200°C; the amount of hydrogen fed is determined by the charging pressure, which is controlled to be 1–7 MPa.

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