Trans-polycyclopentene polymerization catalyst system and its preparation and application

Abstract

This invention discloses a trans-polycyclopentene polymerization catalyst system, comprising a main catalyst, cyclopentene, and an oxygen- or halogen-containing activator. This system is an aged system. The invention also discloses polymerization reactions using this catalytic system. In the catalyst preparation process, the aging of the main catalyst and activator, especially the addition of a small amount of the polymerization monomer cyclopentene during aging, significantly improves the catalyst activity and stability. After aging, the catalyst does not deactivate even after long-term storage at room temperature. Simultaneously, it greatly enhances the catalyst's tolerance to impurities in the polymerization monomer. Furthermore, the monomer added during catalyst preparation can also participate in the polymerization reaction, effectively increasing the monomer concentration in the system, which in turn increases the polymerization conversion rate.

Description

Technical Field

[0001] This invention relates to a catalyst system for the polymerization of trans-polycyclopentene and the preparation and application of trans-polycyclopentene. Background Technology

[0002] Trans-polycyclopentene rubber is produced by ring-opening polymerization of cyclopentene as a monomer under the action of Ziegler-Natta catalyst. It has a low glass transition temperature, high raw rubber strength, crystallization after stretching, excellent resilience and wear resistance of vulcanized rubber, low heat generation, and low rolling resistance, making it very suitable for making heavy-duty vehicle tires and green energy-saving tires.

[0003] When the trans-structure content in trans-polycyclopentene rubber is too low, the rubber does not easily crystallize during stretching, resulting in lower strength. Conversely, if the trans-structure content is too high, the crystallization rate is too fast during stretching. A trans-structure content between 75% and 90% provides the best overall performance. Although trans-polycyclopentene rubber has many advantages, the raw trans-polycyclopentene rubber prepared under current conditions has a high Mooney viscosity, which is detrimental to rubber processing, especially making it difficult to mix evenly with other rubber types and fillers. This limits its application range and hinders the realization of its performance characteristics.

[0004] Early cyclopentene polymerization employed a WCl6-R3Al binary catalytic system, but the polymerization reproducibility was poor. Later, a ternary catalytic system was adopted, with phenols, alcohols, and peroxides being better activators. GB1291185A discloses a method for preparing cyclopentene polymers, comprising: polymerizing cyclopentene in an organic solvent at a temperature of -60 to +60°C in the presence of a group 5b or 6b metal compound and an organoaluminum compound; then adding 0.01-20% (based on the weight of cyclopentene) of an olefin compound, wherein the olefin compound is an acyclic or bicyclic mono-olefin, or an acyclic or polycyclic diene, or a mixture thereof; the polymerization solvent is toluene; and the polymerization reaction is completed in the presence of the olefin compound.

[0005] GB1206079A discloses a method for producing cyclopentene polymers by polymerization of cyclopentene in an inert solvent in the presence of a catalyst. The method includes adding tungsten hexachloride and a peroxide of an alkali metal or alkaline earth metal to a cyclopentene solution in an inert solvent at below 0°C, then adding an organometallic compound of a metal from Groups I to III of the periodic table at a temperature of 30 to -30°C, and collecting the polymer after the polymerization reaction is complete. Toluene is used as the polymerization solvent.

[0006] The Jilin Institute of Applied Chemistry, Chinese Academy of Sciences (Jilin Institute of Applied Chemistry, Chinese Academy of Sciences. Cyclopentene ring-opening polymerization in toluene using WCl6-Et3Al2Cl3-tetrachlorophenol as catalyst [J]. Synthetic Rubber Industry, 1978, 4: 12-18) also reported on the synthesis of trans-polycyclopentene rubber and discovered better polymerization conditions: that is, using the WCl6-Et3Al2Cl3-tetrachlorophenol system, the amount of WCl6 is (2-3)×10 -6 The polymerization parameters were as follows: molar / g monomer ratio, tetrachlorophenol / W molar ratio of 0.5, Al / W molar ratio of 1.0, butene-1 as a molecular weight regulator with a butene-1 / W molar ratio of 2-3, polymerization temperature of 0℃, monomer concentration of 20%, polymerization solvent of toluene, polymerization time of 1-2 hours, and conversion rate greater than 80%. However, the catalysts used in the above synthesis of trans-polycyclopentene rubber have poor stability and are easily deactivated, and the polymerization solvents used are all highly toxic toluene, which is very unfavorable for industrial scale-up. Summary of the Invention

[0007] In previous research on the synthesis of trans-polycyclopentene rubber, the inventors discovered that catalyst aging had a positive effect on its catalytic efficiency. Further research unexpectedly revealed that adding a portion of cyclopentene during catalyst aging significantly improved catalyst activity and stability. The aged catalyst remained active even after prolonged storage at room temperature, and its tolerance to impurities in the monomers was greatly enhanced. Furthermore, the monomers added during catalyst preparation could participate in later polymerization reactions, effectively increasing the monomer concentration in the system. This increased monomer concentration, in turn, improved the polymerization conversion rate, leading to this invention.

[0008] Furthermore, the inventors of this application have discovered that by adding a small amount of branched monoolefin as a molecular weight regulator to a traditional linear monoolefin molecular weight regulator, the molecular weight distribution of trans-polycyclopentene can be broadened, thereby reducing the Mooney viscosity of trans-polycyclopentene rubber, which has high raw rubber strength and is difficult to process, and making it easier to process.

[0009] The inventors also discovered that by using this invention, the polymerization process using low-toxicity straight-chain alkanes or cycloalkanes as polymerization solvents can achieve the same or even better results as using more toxic aromatic hydrocarbons as polymerization solvents.

[0010] As one aspect of the present invention, a trans-polycyclopentene polymerization catalyst system is disclosed, the system comprising a main catalyst, cyclopentene, and an oxygen- or halogen-containing activator, the system being an aged system.

[0011] As another aspect of the present invention, a method for preparing the above-mentioned trans-polycyclopentene polymerization catalyst system is provided: under an inert atmosphere and with stirring, a main catalyst solution is mixed with cyclopentene and an activator solution. The cyclopentene can be added directly to the main catalyst solution followed by aging with the activator, or it can be added after the main catalyst and activator have been mixed and aged.

[0012] As another aspect of the present invention, the application of the above-described trans-polycyclopentene polymerization catalyst system in the trans-polycyclopentene polymerization reaction is involved.

[0013] As another aspect of the present invention, a method for the polymerization of trans-polycyclopentene is provided, comprising:

[0014] Under inert atmosphere and stirring conditions, the above-mentioned trans-polycyclopentene polymerization catalyst system, polymerization solvent, cyclopentene monomer, and molecular weight regulator were added to the reactor, stirred evenly, and then the organoaluminum solution was slowly added.

[0015] In one specific embodiment, the aging conditions include: an aging temperature of -20 to 80°C and an aging time of 5 to 180 minutes, preferably an aging temperature of 10 to 60°C and an aging time of 10 to 90 minutes.

[0016] In one specific embodiment, relative to 1 mole of the main catalyst component, the amount of cyclopentene is 0.2-5 moles, preferably 0.5-2 moles, and cyclopentene can be added in the form of a solution or a pure substance; the amount of the oxygen- or halogen-containing activator is 0.1-5 moles, preferably 0.5-3 moles; the amount of the molecular weight regulator is 0.2-20 moles, preferably 1.0-10 moles; and the amount of the organoaluminum is 1-10 moles, preferably 2-6 moles.

[0017] In one specific embodiment, the main catalyst component is selected from one or more of tungsten halides, tungsten oxyhalides, tungsten alkoxyhalides, molybdenum halides, molybdenum oxyhalides, and molybdenum alkoxyhalides; preferably, the main catalyst component is selected from one or more of WCl6, WBr6, WCl2, WBr2, WOCl4, WOBr4, MoCl5, and MoBr5.

[0018] In one specific embodiment, the oxygen- or halogen-containing activator is selected from one or more polyhalogenated phenols; preferably, the polyhalogenated phenol is selected from one or more of trichlorophenol, tetrachlorophenol, pentachlorophenol, dichlorophenol, dibromophenol, tribromophenol, diiodophenol, and triiodophenol, and particularly preferably, the polyhalogenated phenol is trichlorophenol.

[0019] In one specific embodiment, the molecular weight regulator is selected from one or more linear monoolefins having 2 to 10 carbon atoms and a mixture of one or more branched monoolefins having 2 to 10 carbon atoms; preferably, the linear monoolefin molecular weight regulator is selected from one or more of 1-butene, 2-butene, 1-hexene and 1-octene, and the branched monoolefin is selected from 2-methyl-2-butene and 2-methyl-butene.

[0020] In one specific embodiment, the molar ratio of the straight-chain monoolefin to the branched monoolefin is 1:0.1 to 10, preferably 1:0.5 to 5.

[0021] In one specific embodiment, the organoaluminum compound is an alkylaluminum and / or an alkylaluminum halide; preferably, the alkylaluminum is selected from one or more of triisobutylaluminum and triethylaluminum; the alkylaluminum halide is selected from one or more of diethylaluminum chloride, diethylaluminum chloride, dibutylaluminum chloride, dibutylaluminum chloride, diethylaluminum bromodiethylaluminum, diethylaluminum bromodiethylaluminum, dibutylaluminum bromodiethylaluminum, and dibutylaluminum bromodiethylaluminum.

[0022] In one specific embodiment, the amount of the main catalyst component is 0.5 × 10⁻⁶ per gram of the polymerization monomer. -6 ~8×10 -6 mol, preferably 1.0 × 10⁻⁶ -6 ~3.5×10 -6 mol.

[0023] In one specific embodiment, the polymerization reaction conditions include: a reaction temperature of -40 to 50°C, a reaction pressure of 0.01 to 1 MPa, a polymerization time of 0.5 to 6 hours after adding organoaluminum, and a monomer concentration of 10 to 60% by weight in the reaction mixture; preferably, the polymerization reaction conditions include: a reaction temperature of -20 to 30°C, a reaction pressure of 0.05 to 0.5 MPa, a polymerization time of 1 to 4 hours after adding organoaluminum, and a monomer concentration of 15 to 40% by weight in the reaction mixture.

[0024] Preferably, in one specific embodiment, the solvent for dissolving the main catalyst, cyclopentene, and activator is selected from one or more of toluene, xylene, and benzene; the polymerization solvent is selected from one or more of n-pentane, n-hexane, n-heptane, n-octane, cyclopentane, and cyclohexane.

[0025] As another aspect of the present invention, it relates to the application of trans-polycyclopentene prepared by the above method in tire manufacturing, such as its use as rubber products, for example, as tire tread compound, tire shoulder compound, tire sidewall compound, etc.

[0026] The method of the present invention is characterized in that the catalyst and the method for preparing trans-polycyclopentene are not only suitable for the polymerization of high-purity cyclopentene monomers, but also suitable for the polymerization of cyclopentene containing a certain amount of impurities, wherein the monomers contain 20-60 ppm water, 100-2000 ppm cyclopentadiene, and 100-500 ppm isoprene.

[0027] According to the method of the present invention, the trans polycyclopentene rubber has a trans structure content of 65% to 95%, a number average molecular weight of 60,000 to 1,500,000, a molecular weight distribution of 1.5 to 6.0, a glass transition temperature of less than -90°C, a gel content of less than 2.0% by mass, and a Mooney viscosity of 30 to 120.

[0028] More preferably, the trans-polycyclopentene rubber has a trans structure content of 75% to 90%, a number average molecular weight of 100,000 to 600,000, a molecular weight distribution of 1.9 to 4.0, a glass transition temperature of less than -92°C, a gel content of less than 1.0% by mass, and a Mooney viscosity of 40 to 100.

[0029] This invention overcomes the shortcomings of existing technologies, such as poor catalyst stability, low catalyst activity and polymerization conversion rate, and poor catalyst tolerance to impurities in the monomers. In particular, the synthesized trans-polycyclopentene rubber raw rubber has high Mooney viscosity and is difficult to process. This invention provides a method for preparing trans-polycyclopentene. In the catalyst preparation process, the aging of the main catalyst and activator, especially the addition of a small amount of the monomer cyclopentene during aging, significantly improves the catalyst activity and stability. After aging, the catalyst does not deactivate even after long-term storage at room temperature. Simultaneously, it greatly enhances the catalyst's tolerance to impurities in the monomers. Furthermore, the monomer added during catalyst preparation can also participate in the polymerization reaction, effectively increasing the monomer concentration in the system, which in turn improves the polymerization conversion rate. Moreover, using this invention, the polymerization process with low-toxicity straight-chain alkanes or cycloalkanes as polymerization solvents can achieve the same or even better results than using more toxic aromatic hydrocarbons as polymerization solvents. Furthermore, experiments have shown that by adding a small amount of branched monoolefin as a molecular weight regulator to traditional linear monoolefin molecular weight regulators, the molecular weight distribution of trans-polycyclopentene can be broadened, thereby making the processing of trans-polycyclopentene rubber, which has high raw rubber strength and is difficult to process, easier. Therefore, this invention has very good economic value and important practical significance.

[0030] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0031] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0032] The testing method involved in this invention is as follows:

[0033] 1. The microstructure of the polymer was determined using a commercially available Bruker AVANCE400 superconducting nuclear magnetic resonance spectrometer (NMR spectrometer). 1 The determination was performed by ¹H-NMR using deuterated chloroform (CDCl₃) as the solvent at 25°C, and calibrated by TMS.

[0034] 2. The number-average molecular weight and molecular weight distribution index of the polymer were determined using a Shimadzu LC-10AVP gel permeation chromatography (GPC) system at 25°C, with tetrahydrofuran as the mobile phase and a flow rate of 1.0 ml / min.

[0035] 3. The glass transition temperature was determined using a TA Instruments MDSC2910 differential scanning calorimeter (DSC) with a modulation period of 60 seconds, a modulation amplitude of ±1.5℃, a heating rate of 10℃ / min, nitrogen protection, and a flow rate of 50mL / min.

[0036] 4. The polymerization conversion rate is calculated from the weight of the obtained polymer. The calculation formula is (W1-W2) / W1×100%, where W1 is the weight of the polymerized monomer and W2 is the weight of the obtained polymer.

[0037] 5. The method for testing the gel content is to place the polymer in a stainless steel mesh, immerse it in toluene for a certain period of time, and measure the percentage of the portion that is insoluble in toluene, which is the gel content.

[0038] Preparation Examples 1-8 and Comparative Examples 1-3 are used to illustrate the catalyst solution and its preparation method.

[0039] Preparation Example 1

[0040] 100 mL of a 0.05 M WCl6 toluene solution was added to a reaction system fully purged with purified nitrogen. Then, under stirring, 10 mL of a 0.5 M cyclopentene toluene solution and 150 mL of a 0.05 M trichlorophenol toluene solution were added. The system temperature was maintained at 30 °C. The resulting mixture was aged for another 60 minutes under stirring. The solution color changed from dark blue to purplish-red, yielding catalyst solution A. The molar ratio of the main catalyst component, cyclopentene, and oxygen- or halogen-containing activator in this catalyst solution was 1.0:1.0:1.5.

[0041] Preparation Example 2

[0042] 100 mL of a 0.05 M WOCl4 toluene solution was added to a reaction system fully purged with purified nitrogen. Then, 5 mL of a 0.5 M cyclopentene toluene solution and 300 mL of a 0.05 M tetrachlorophenol toluene solution were added under stirring. The system temperature was maintained at 10 °C. The resulting mixture was aged for another 90 minutes under stirring. The solution color changed from dark blue to purplish-red, yielding catalyst solution B. The molar ratio of the main catalyst component, cyclopentene, and oxygen- or halogen-containing activator in this catalyst solution was 1.0:0.5:3.0.

[0043] Preparation Example 3

[0044] 100 mL of a 0.05 M WBr6 toluene solution was added to a reaction system fully purged with purified nitrogen. Then, under stirring, 0.82 mL (10 mmol) of cyclopentene and 50 mL of a 0.05 M tribromophenol toluene solution were added. The system temperature was maintained at 60 °C. The resulting mixture was aged for another 10 minutes under stirring, and the solution color was observed to change from dark blue to purplish-red, yielding catalyst solution C. The molar ratio of the main catalyst component, cyclopentene, and oxygen- or halogen-containing activator in this catalyst solution was 1.0:2.0:0.5.

[0045] Preparation Example 4

[0046] 100 mL of a 0.05 M WCl6 toluene solution was added to a fully purged reaction system. Then, 150 mL of a 0.05 M trichlorophenol toluene solution was added with stirring. The system temperature was maintained at 30 °C. The resulting mixture was aged for another 30 minutes with stirring, observing the solution color change from dark blue to purplish-red. Then, 10 mL of a 0.5 M cyclopentene toluene solution was added, and the mixture was aged for another 30 minutes with stirring. The solution color remained purplish-red, yielding catalyst solution D. The molar ratio of the main catalyst component, cyclopentene, and oxygen- or halogen-containing activator in this catalyst solution was 1.0:1.0:1.5.

[0047] Preparation Example 5

[0048] The catalyst solution prepared in Example 1 was left at room temperature and protected from light for six months. The catalyst solution remained a purplish-red transparent solution, and no precipitation occurred. Catalyst solution E was obtained.

[0049] Preparation of Comparative Example 1

[0050] The preparation method was followed as in Example 1, except that no cyclopentene was added to the toluene solution, ultimately yielding catalyst solution F. After being left at room temperature in the dark for 5 days, the purplish-red color of the catalyst solution lightened, and a small amount of precipitate formed.

[0051] Preparation of Comparative Example 2

[0052] The preparation method of Example 1 was followed, except that the toluene solution of trichlorophenol was not added, ultimately yielding catalyst solution G. After being placed at room temperature in the dark for two days, the catalyst solution changed from a transparent deep blue solution to a turbid light blue solution with a small amount of precipitate forming.

[0053] Preparation of Comparative Example 3

[0054] The polymerization was carried out according to the method of Preparation Example 1, except that the catalyst was not aged; instead, the active component, cyclopentene, and an oxygen- or halogen-containing activator were directly added to the polymerization reaction system to carry out the polymerization reaction, following existing techniques. The catalyst used was H.

[0055] Example 1

[0056] In a 2L reactor fully purged with purified nitrogen, 128g of purified cyclopentene (the cyclopentene used was a reagent-grade product with a purity greater than 99%, which was soaked in 5A molecular sieve and activated alumina for more than two weeks and bubbled with high-purity nitrogen to remove oxygen before use, with a water content of less than 10ppm, a cyclopentadiene content of less than 10ppm, and an isoprene content of less than 10ppm), 512g of purified hexane, and the catalyst solution prepared in Preparation Example 1 were added. The mixture was stirred evenly and the temperature of the reactants was kept at 0°C. Then, under stirring conditions, 0.5M of 1-butene hexane solution and 0.5M of 2-methyl-2-butene hexane solution were added, followed by the slow addition of 0.5M of triisobutylaluminum hexane solution. The reaction was continued for 3.0h. After the reaction was completed, 12.8 mL of an ethanol solution containing 10% 2,6-di-tert-butyl-4-methylphenol was added to the reactor to terminate the polymerization reaction. The amount of 2,6-di-tert-butyl-4-methylphenol was 0.5% by weight based on the amount of monomer. The gel was then discharged and coagulated with ethanol. The resulting polymer was dried to constant weight in a vacuum oven at 60°C. The catalyst dosage was 2.5 × 10⁻⁶. -6 The monomer concentration was 20 mol / g, and the molar ratio of each component added was W: cyclopentene: trichlorophenol: 1-butene: 2-methyl-2-butene: triisobutylaluminum = 1.0: 1.0: 1.5: 1.0: 3.0: 4.0.

[0057] The polymerization results are shown in Table 1.

[0058] Example 2

[0059] The process was essentially a repeat of Example 1, except that the catalyst used was the same as that used in Preparation Example 2, and the amount of catalyst was 3.5 × 10⁻⁶. -6The monomer concentration was 15% by weight (mol / g), with 1-octene replacing 1-butene and diisobutylaluminum chloride replacing triisobutylaluminum. The molar ratio of each component was W:cyclopentene:trichlorophenol:1-octene:2-methyl-2-butene:diisobutylaluminum chloride = 1.0:0.5:3.0:6.0:4.0:2.0, and the polymerization temperature was -20℃. The polymerization results are shown in Table 1.

[0060] Example 3

[0061] The polymerization reaction was essentially a repeat of Example 1, except that the catalyst used was the same as that used in Example 3. The catalyst dosage was 1.0 × 10⁻⁶ mol / g monomer, the monomer concentration was 30% by weight, 1-butene was replaced with 2-butene, 2-methyl-butene was replaced with 2-methyl-2-butene, and triethylaluminum was replaced with triisobutylaluminum. The molar ratio of each component was W:cyclopentene:trichlorophenol:1-butene:2-methyl-butene:triethylaluminum = 1.0:2.0:0.5:0.5:0.5:6.0, and the polymerization temperature was 10 °C. The polymerization results are shown in Table 1.

[0062] Example 4

[0063] The process was essentially a repeat of Example 1, except that the catalyst used was the same as that used in Preparation Example 4, and the amount of catalyst was 1.5 × 10⁻⁶. -6 The monomer concentration was 40% by weight (mol / g), with dibromoethylaluminum replacing triisobutylaluminum. The molar ratio of each component was W:cyclopentene:trichlorophenol:1-butene:2-methyl-2-butene:dibromoethylaluminum = 1.0:1.0:1.5:0.5:2.5:3.0, and the polymerization temperature was 20℃. The polymerization results are shown in Table 1.

[0064] Example 5

[0065] The process was essentially a repeat of Example 1, except that the catalyst dosage was 3.5 × 10⁻⁶. -6 The monomer concentration was 20% by weight, and the molar ratio of each component added was W: cyclopentene: trichlorophenol: 1-butene: 2-methyl-2-butene: triisobutylaluminum = 1.0: 1.0: 2.5: 2.0: 1.0: 6.0. The polymerization results are shown in Table 1.

[0066] Example 6

[0067] The process was essentially a repeat of Example 1, except that the catalyst dosage was 1.0 × 10⁻⁶. -6 The monomer concentration was 20% by weight, and the molar ratio of each component added was W: cyclopentene: trichlorophenol: 1-butene: 2-methyl-2-butene: triisobutylaluminum = 1.0: 1.0: 1.5: 0.5: 5.0: 2.0. The polymerization results are shown in Table 1.

[0068] Example 7

[0069] The process was essentially a repeat of Example 1, except that the catalyst used was the same as that used in Preparation Example 5, and the amount of catalyst was 2.5 × 10⁻⁶. -6 The monomer concentration was 50% by weight, and the molar ratio of each component added was W: cyclopentene: trichlorophenol: 1-butene: 2-methyl-2-butene: triisobutylaluminum = 1.0: 1.0: 1.5: 1.0: 0.5: 5.0. The polymerization results are shown in Table 1.

[0070] Comparative Example 1

[0071] The reaction was basically the same as in Example 1, except that the catalyst used was the same as that used in Comparative Example 1. The polymerization results are shown in Table 1.

[0072] Comparative Example 2

[0073] The reaction was basically the same as in Example 1, except that the catalyst used was the same as that used in Comparative Example 2. The polymerization results are shown in Table 1.

[0074] Comparative Example 3

[0075] The reaction was basically the same as Example 1, except that the toluene solution of the main catalyst, cyclopentene and trichlorophenol used in step (1) was added directly to the reaction system without aging, which is the catalyst used to prepare Comparative Example 3. The polymerization results are shown in Table 1.

[0076] Comparative Example 4

[0077] The process was basically the same as Example 1, except that a hexane solution of 2-methyl-2-butene was not added in step (2). The polymerization results are shown in Table 1.

[0078] As can be seen from Examples 1-5, Comparative Examples 1-4, and Table 1, the catalyst of this invention exhibits good stability, high catalyst activity, and high polymerization conversion rate. The resulting trans-polycyclopentene rubber has a suitable trans-structure content, low gel content, and low glass transition temperature. In particular, the composite use of linear and branched monoolefin molecular weight regulators allows for the adjustment of the polymer's molecular weight and its distribution, making the Mooney viscosity of the product controllable. This is beneficial for the processing and application of trans-polycyclopentene rubber, thereby enhancing its performance and characteristics. In contrast, the comparative examples either have poor catalyst stability and low polymerization conversion rate, or the resulting products have a narrow molecular weight distribution and high Mooney viscosity, which are detrimental to the processing and application of the products.

[0079] Example 8

[0080] The process was essentially a repeat of Example 1, except that the cyclopentene monomer used was a C5 separated product containing 60 ppm water, less than 10 ppm cyclopentadiene, and less than 10 ppm isoprene. The polymerization results are shown in Table 2.

[0081] Example 9

[0082] The process was essentially a repeat of Example 1, except that the polymerizable monomer cyclopentene used was a C5 separated product, containing less than 10 ppm water, 2000 ppm cyclopentadiene, and less than 10 ppm isoprene. The polymerization results are shown in Table 2.

[0083] Example 10

[0084] The process was essentially a repeat of Example 1, except that the cyclopentene monomer used was a C5 separated product, containing less than 10 ppm water, less than 10 ppm cyclopentadiene, and 500 ppm isoprene. The polymerization results are shown in Table 2.

[0085] Example 11

[0086] The process was essentially a repeat of Example 1, except that the polymerizable monomer cyclopentene was a hydrogenated cyclopentadiene product containing 20 ppm water, 100 ppm cyclopentadiene, and 100 ppm isoprene. The polymerization results are shown in Table 2.

[0087] Comparative Example 5

[0088] The process was essentially a repeat of Example 1, except that the catalyst used was the same as that used in Comparative Example 1, and the polymerizable monomer cyclopentene was a hydrogenated cyclopentadiene product containing 60 ppm water, less than 10 ppm cyclopentadiene, and less than 10 ppm isoprene. The polymerization results are shown in Table 2.

[0089] Comparative Example 6

[0090] The process was essentially a repeat of Example 1, except that the catalyst used was the same as that used in Comparative Example 2, and the polymerizable monomer cyclopentene was a hydrogenated cyclopentadiene product containing less than 10 ppm of water, 2000 ppm of cyclopentadiene, and less than 10 ppm of isoprene. The polymerization results are shown in Table 2.

[0091] Comparative Example 7

[0092] The process was essentially a repeat of Example 1, except that the catalyst used was the same as that used in Comparative Example 3, and the polymerizable monomer cyclopentene was a hydrogenated cyclopentadiene product containing less than 10 ppm of water, less than 10 ppm of cyclopentadiene, and 500 ppm of isoprene. The polymerization results are shown in Table 2.

[0093] Comparative Example 8

[0094] The reaction was basically repeated in Example 1, except that the toluene solution of the main catalyst, cyclopentene and trichlorophenol used in step (1) was added directly to the reaction system without aging. The polymerization monomer cyclopentene was a hydrogenated product of cyclopentadiene, which contained 20 ppm water, 100 ppm cyclopentadiene and 100 ppm isoprene. The polymerization results are shown in Table 2.

[0095] As can be seen from Examples 1 and 7-10, the catalyst of this invention has very good activity and stability, and its tolerance to impurities in the system is excellent, making it highly practical. Moreover, the presence of impurities in the system has little impact on the structure and performance of the final product. In contrast, the comparative catalyst has poor activity and stability, low polymerization conversion rate, and the resulting product has a relatively narrow molecular weight distribution and high Mooney viscosity, which is not conducive to product processing and application.

[0096] Comparative Example 9

[0097] The process was essentially a repeat of Example 1, except that the polymerization solvent was toluene. The resulting polymerization conversion rate was 82.0%, and the polymer structure was: Mn = 390000, Mw / Mn = 1.98, trans-structure content 73.5%, gel content 1.5%, glass transition temperature -93.2℃, and ML... (1+4) 100℃ The value is 110.

[0098] Table 1.

[0099]

[0100] Table 2

[0101]

[0102] As can be seen from Example 1 and Comparative Example 9, using the low-toxicity straight-chain alkane n-hexane as the polymerization solvent results in a polymerization conversion rate comparable to that of using the more toxic toluene as the polymerization solvent. The polymer exhibits a similar or higher content of trans structures, lower gel content, similar or lower glass transition temperature, more suitable Mooney viscosity, and better overall performance. Low-toxicity straight-chain alkanes can completely replace the more toxic toluene as a polymerization solvent.

[0103] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention. Furthermore, it should be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. In addition, various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the spirit of the present invention, they should also be considered as the content disclosed by the present invention.

Claims

1. A method for polymerizing trans-polycyclopentene, characterized in that, include: Under inert atmosphere and stirring conditions, the trans-polycyclopentene polymerization catalyst system, polymerization solvent, cyclopentene monomer, and molecular weight regulator are added to the reactor, stirred evenly, and then the organoaluminum solution is slowly added. The trans-polycyclopentene polymerization catalyst system contains a main catalyst, cyclopentene, and an oxygen- or halogen-containing activator, and the system is an aged system. The polymerization solvent is selected from one or more of n-pentane, n-hexane, n-heptane, n-octane, cyclopentane, and cyclohexane; The molecular weight regulator is a mixture of straight-chain monoolefins and branched monoolefins; the straight-chain monoolefin is selected from one or more of 1-butene, 2-butene, 1-hexene and 1-octene, and the branched monoolefin is selected from 2-methyl-2-butene and 2-methyl-butene.

2. The method according to claim 1, characterized in that, The amount of the molecular weight regulator is 0.2 to 20 moles relative to 1 mole of the main catalyst, and the amount of the organoaluminum is 1 to 10 moles.

3. The method according to claim 2, characterized in that, The amount of the molecular weight regulator is 1.0 to 10 moles relative to 1 mole of the main catalyst, and the amount of the organoaluminum is 2 to 6 moles.

4. The method according to claim 1, characterized in that, The molar ratio of the straight-chain monoolefin to the branched monoolefin is 1:0.1 to 10.

5. The method according to claim 4, characterized in that, The molar ratio of the straight-chain monoolefin to the branched monoolefin is 1:0.5 to 5.

6. The method according to claim 1, characterized in that, The organoaluminum is an alkylaluminum and / or an alkylaluminum halide; the alkylaluminum is selected from one or more of triisobutylaluminum and triethylaluminum; the alkylaluminum halide is selected from one or more of diethylaluminum chloride, diethylaluminum chloride, dibutylaluminum chloride, dibutylaluminum chloride, diethyl ...

7. The method according to claim 1, characterized in that, For each gram of the cyclopentene monomer, the amount of the main catalyst is 0.5 × 10⁻⁶. -6 ~8×10 -6 mol.

8. The method according to claim 7, characterized in that, For each gram of the cyclopentene monomer, the amount of the main catalyst is 1.0 × 10⁻⁶. -6 ~3.5×10 -6 mol.

9. The method according to claim 1, characterized in that, The aging process involves an aging temperature of -20 to 80°C and an aging time of 5 to 180 minutes.

10. The method of claim 9, characterized in that, The aging process involves an aging temperature of 10-60℃ and an aging time of 10-90 minutes.

11. The method according to claim 1, characterized in that, In the trans-polycyclopentene polymerization catalyst system: relative to 1 molar part of the main catalyst, the amount of cyclopentene is 0.2-5 molar parts, and the amount of the oxygen- or halogen-containing activator is 0.1-5 molar parts.

12. The method of claim 11, characterized in that, In the trans-polycyclopentene polymerization catalyst system: relative to 1 mole of the main catalyst, the amount of cyclopentene is 0.5-2 moles, and the amount of the oxygen- or halogen-containing activator is 0.5-3 moles; the cyclopentene is added in the form of a solution or a pure substance.

13. The method according to claim 1, characterized in that, The main catalyst is selected from one or more of tungsten halides, tungsten oxyhalides, tungsten alkoxy compounds, molybdenum halides, molybdenum oxyhalides, and molybdenum alkoxy compounds.

14. The method of claim 13, characterized in that, The main catalyst is selected from one or more of WCl6, WBr6, WCl2, WBr2, WOCl4, WOBr4, MoCl5, and MoBr5.

15. The method according to claim 1, characterized in that, The oxygen- or halogen-containing activator is selected from one or more of trichlorophenol, tetrachlorophenol, pentachlorophenol, dichlorophenol, dibromophenol, tribromophenol, diiodophenol, and triiodophenol.

16. The method of claim 15, characterized in that, The oxygen- or halogen-containing activator is trichlorophenol.

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