Cycloolefin polymer as well as preparation method and application thereof

Abstract

The invention relates to the field of cycloolefin polymers, in particular to a cycloolefin polymer and a preparation method and application thereof.According to the cycloolefin polymer, structural units shown in a formula I, a formula II and a formula III jointly act at a specific molar ratio, so that the cycloolefin polymer has excellent optical performance, thermal stability and flexibility; especially, an elastomer unit with a cyclohexyl side group is introduced to a norbornene and derivative unit main chain, and a flexible aliphatic alkyl unit is introduced to a norbornene and derivative unit side chain multi-ring, so that the rigidity and flexibility adjustable range of the COP polymer is wide, the material flexibility is improved through the elastomer unit, and the rigidity and flexibility of the COP polymer are improved. And the internal stress of the material during molding is reduced, the brittleness is improved, the COP polymer is endowed with excellent mechanical properties, and meanwhile, the excellent optical properties and thermal stability of the cycloolefin polymer are also maintained.

Description

Technical Field

[0001] The present invention relates to the field of cycloolefin polymers, and in particular to a cycloolefin polymer and a preparation method and application thereof. Background Art

[0002] Cyclic Olefin Polymer (COP) is an amorphous transparent polymer material with a highly sterically hindered cyclic alkane structure. It has excellent properties such as high transparency, high refractive index, low birefringence, high Abbe number, high heat resistance, chemical resistance, dimensional stability, and low hygroscopicity. It is widely used in optical lenses, optical films, polarizers, medical, biopharmaceutical packaging and other fields.

[0003] COP is prepared from norbornene monomers through ring-opening heterositu polymerization and subsequent hydrogenation. During the COP synthesis process, the ring structure of norbornene is destroyed, resulting in a 1:1 ratio of alternating five-membered ring structures and ethylene segments, achieving a sequence distribution of cycloolefins and α-olefins. This structure can achieve good optical properties. However, the molar ratio of the cyclic monomers in COP is 50%, and the proportion of rigid groups is high. As a result, the material has high internal stress after molding, which affects mechanical properties. Moreover, the rigidity-flexibility ratio on the main chain is fixed and cannot be adjusted. In addition, to improve the refractive index and heat resistance of COP materials, polycyclic or fused ring structures with large steric hindrance are often used on the side chains. However, this can lead to excessive rigidity, poor toughness, brittleness after molding, and difficulty in processing. Therefore, improving the flexibility of COP and resolving processing challenges remain the main direction of material improvement. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the cycloolefin polymers in the prior art that cannot achieve both high flexibility and excellent mechanical properties, high transparency and high heat resistance, thereby providing a cycloolefin polymer and its preparation method and application.

[0005] To this end, the present application provides a cycloolefin polymer, which comprises structural units shown in the following formulas I, II and III:

[0006]

[0007] In Formula I, R1, R2, R7, and R8 are each independently selected from any one of hydrogen, substituted or unsubstituted C1-C20 linear or branched alkyl, and substituted or unsubstituted C3-C20 cycloalkyl; "substituted" means that the H atom in the alkyl or cycloalkyl group is replaced by a halogen atom or a C1-C6 linear or branched alkyl group;

[0008] In Formula II, n is 0, 1 or 2; R3, R4, R5, and R6 are each independently selected from at least one of halogen, unsubstituted or halogenated C1-C20 linear or branched alkyl, unsubstituted or halogenated C3-C20 cycloalkyl, and C6-C20 aryl; R3 and R4 are bonded to each other to form a ring or are not bonded; "substituted" means that the H atom in the alkyl or cycloalkyl group is replaced by a halogen atom or a C1-C6 linear or branched alkyl group;

[0009] In formula III, the value of p is an integer from 2 to 8;

[0010] The molar ratio of the structural unit represented by formula I, the structural unit represented by formula II and the structural unit represented by formula III is 5-95:5-95:0.5-50.

[0011] Furthermore, the cycloolefin polymer satisfies one or more of the following AC:

[0012] A, R1, R2, R7, and R8 are each independently selected from hydrogen or a C1-C6 straight or branched chain alkyl group;

[0013] B, R3, and R4 are selected from hydrogen, C1-C6 straight or branched chain alkyl;

[0014] C, R5, and R6 are selected from hydrogen.

[0015] Furthermore, the structural unit represented by Formula I has one of the following structures:

[0016] Furthermore, the structural unit represented by Formula II has one of the following structures:

[0017]

[0018] Furthermore, the structural unit represented by formula III has one of the following structures:

[0019]

[0020] Furthermore, the cycloolefin polymer satisfies one or more of the following AC:

[0021] A, the molar ratio of the structural unit represented by formula I, the structural unit represented by formula II and the structural unit represented by formula III is 30-50:30-55:10-30, more preferably 30-50:45-55:12-20;

[0022] B. The cycloolefin polymer has a weight average molecular weight of 5,000 to 50,000 and a molecular weight distribution of 1.5 to 3.0;

[0023] C. The double bond molar content of the cycloolefin polymer is ≤10%, preferably ≤1%.

[0024] The present invention also provides a method for preparing any of the above-mentioned cycloolefin polymers, comprising the steps of:

[0025] Step S1: subjecting a monomer composition comprising monomers represented by Formula A, Formula B, and Formula C to a ring-opening polymerization reaction in the presence of a catalyst and a chain transfer agent to obtain a copolymer:

[0026] Step S2: hydrogenating the copolymer in the presence of a hydrogenation catalyst to obtain a cycloolefin polymer;

[0027]

[0028] In formula A, R1, R2, R7, and R8 are as defined above;

[0029] In formula B, n, R3, R4, R5, and R6 are as defined above;

[0030] In formula C, It represents a straight-linked alkyl group of 3 to 9 carbon atoms.

[0031] Furthermore, the monomer represented by formula A has at least one of the following structures:

[0032]

[0033] Furthermore, the monomer represented by formula B has at least one of the following structures:

[0034]

[0035] Furthermore, the monomer represented by formula C has at least one of the following structures:

[0036]

[0037]

[0038] Furthermore, in step S1, the monomers represented by formula A, formula B and formula C are mixed with a chain transfer agent and an inert solvent, and then mixed with a polymerization catalyst solution to perform a ring-opening polymerization reaction;

[0039] Optionally, the inert solvent is selected from at least one of n-hexane, heptane, cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, benzene, toluene, and xylene;

[0040] Optionally, the mass percentage of the monomer composition to the total mass of the solvent and the monomer composition is 5 to 60%, preferably 15 to 40%;

[0041] Optionally, the mass percentage concentration of the polymerization catalyst solution is 0.01 to 0.05%.

[0042] Furthermore, the preparation method satisfies one or more of the following AC:

[0043] A. The chain transfer agent is selected from at least one of 1-hexene, 1-octene, styrene, and vinyl ether; and / or the ratio of the mass of the chain transfer agent to the total mass of the monomer composition is 1:50-5000;

[0044] B. The catalyst for the ring-opening polymerization reaction is selected from one or more of a tungsten-based catalyst, a Grubbs series catalyst, and a Schrock series catalyst; and / or the ratio of the mass of the catalyst for the ring-opening polymerization reaction to the total mass of the monomer composition is 1:10,000-100,000;

[0045] C. The temperature of the ring-opening polymerization reaction is 0 to 200° C., preferably 50 to 150° C.; the time is 1 to 60 minutes, preferably 1 to 20 minutes.

[0046] Furthermore, the preparation method satisfies one or more of the following AC:

[0047] A. The hydrogenation catalyst comprises a homogeneous catalyst and / or a heterogeneous catalyst;

[0048] Preferably, the heterogeneous catalyst is selected from at least one of metal-supported silica, metal-supported alumina, metal-supported titanium oxide, skeletal nickel, and palladium-carbon catalyst; wherein the metal is selected from at least one of nickel, palladium, platinum, rhodium, and ruthenium; more preferably, it is at least one of palladium-carbon catalyst and nickel-supported silica;

[0049] Preferably, the amount of the heterogeneous catalyst added is 0.25 to 10% of the mass of the reaction solution during the hydrogenation reaction;

[0050] Preferably, the homogeneous catalyst is selected from at least one of soluble complexes of nickel, titanium, palladium, platinum, rhodium, and ruthenium metals; more preferably, it is a nickel acetylacetonate catalyst;

[0051] Preferably, the mass of the metal in the homogeneous catalyst is 0.001 to 10% of the mass of the reaction liquid during the hydrogenation reaction;

[0052] B. The hydrogenation reaction temperature is 80-200°C, the pressure is 1-7 MPa, and the time is 1-10 h;

[0053] In step C and S2, the copolymer solution is mixed with a solvent and a hydrogenation catalyst and then subjected to a hydrogenation reaction to obtain a cycloolefin polymer.

[0054] The present invention also provides the use of any of the above-mentioned cycloolefin polymers or the cycloolefin polymers prepared by any of the above-mentioned preparation methods in optical materials, electronic materials, packaging materials or medical materials.

[0055] The technical solution of the present invention has the following advantages:

[0056] 1. The present invention provides a cycloolefin polymer, comprising structural units represented by the following formulas I, II, and III, wherein the molar ratio of the structural unit represented by formula I, the structural unit represented by formula II, and the structural unit represented by formula III is 5-95:5-95:0.5-50. By combining the structural units represented by formulas I, II, and III at a specific molar ratio, the cycloolefin polymer achieves excellent optical properties, thermal stability, and flexibility. In particular, by introducing an elastomer unit with a cyclohexyl side group into the main chain of norbornene and its derivative units, and introducing a flexible aliphatic alkyl unit into the polycyclic side chains of norbornene and its derivative units, the COP polymer achieves a wide range of adjustable rigidity and flexibility. The elastomer unit improves the material's flexibility, reduces the internal stress of the material during molding, improves brittleness, and imparts excellent mechanical properties to the COP polymer while maintaining the excellent optical properties and thermal stability of the cycloolefin polymer.

[0057] 2. In the cycloolefin polymer provided by the present invention, the molar ratio of the structural unit represented by Formula I, the structural unit represented by Formula II, and the structural unit represented by Formula III is 30-50:30-55:10-30. By controlling the molar ratio of the structural units represented by Formula I, Formula II, and Formula III within the above range, especially preferably controlling the molar ratio of the three to be 30-50:45-55:12-20, the flexibility and mechanical properties of the cycloolefin polymer can be further improved. DETAILED DESCRIPTION

[0058] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0059] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0060] In the following specific implementations of the present invention, the performance evaluation method involved is as follows:

[0061] 1. Glass transition temperature (Tg) The Tg of cycloolefin polymers was measured by differential scanning calorimetry (NETZSCH DSC 204F1) under nitrogen protection, with a heating rate of 10°C / min and two cycles from room temperature to 230°C.

[0062] 2. Thermal decomposition temperature (Td, 5%)

[0063] The Td, 5% of the cycloolefin polymer was measured by thermogravimetric analysis (TGA) according to standard ISO 11358-1:2022.

[0064] 3. Weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)

[0065] Gel permeation chromatography (GPC) testing was performed using a Shimadzu liquid chromatograph (LC 20AD feed system with RID10A detector) and a GPC detection system consisting of a Tosoh GPC column (model TSKgel GMHHR). The column temperature was 120°C, o-dichlorobenzene was used as the eluent, the flow rate was 1.0 mL / min, and the concentration of the polymer solution was 1 mg / mL.

[0066] 4. Tensile strength, tensile modulus, and chain breaking elongation

[0067] Tested according to standard GB / T 1701-2001.

[0068] 5. Flexural strength and flexural modulus

[0069] Tested according to standard GB / T 37781-2019.

[0070] 6. Impact strength

[0071] The Izod notched impact strength was tested according to the method in standard ASTM D256.

[0072] 7. Transmittance in the visible light region

[0073] The hydrogenated cycloolefin polymer to be tested was made into a 50 mm×50 mm×3 mm film and measured using an ultraviolet spectrophotometer (U-3900, manufactured by Hitachi Ltd.). The average transmittance of the film in the wavelength range of 380-780 nm was calculated.

[0074] Example 1

[0075] This embodiment provides a cycloolefin polymer comprising structural units in a molar ratio of 0.30:0.55:0.15.

[0076] The preparation method is as follows: the entire continuous polymerization system is fully nitrogen-purged, 10 kg of a mixed monomer solution (total concentration of the mixed monomer is 30 wt % and the solvent is cyclohexane) is added to a monomer configuration tank, wherein the mixed monomer is composed of dicyclopentadiene (compound D-1, CAS No. 77-73-6), tetracyclododecene (compound T-3, CAS No. 21635-90-5), and 3-phenylcyclododecene (compound M-3, CAS No. 71445-74-4) in a molar ratio of 0.30:0.55:0.15. Then, 2.5 g of a chain transfer agent, 1-hexene, is added to the monomer configuration tank, and the mixture is stirred and mixed to obtain a mixed monomer solution. 0.5 kg of a polymerization catalyst solution (Grubbs second-generation catalyst, the solvent is cyclohexane) with a concentration of 0.03 wt % is added to a catalyst feed tank. The monomer solution was continuously supplied at a rate of 17.8 kg / hr and the polymerization catalyst solution was continuously supplied at a rate of 0.9 kg / hr into a 2 L continuous reactor, and a ring-opening polymerization reaction was carried out at 90°C with stirring for a residence time of 5 min to obtain a copolymer solution, which was designated as HDTM-1 copolymer solution. The conversion rate of the monomer to the polymer was >99%, and the HDTM-1 copolymer solution was continuously discharged into a polymerization product tank for collection.

[0077] 10.5 kg of the obtained HDTM-1 copolymer solution was added to a 30 L hydrogenation reactor, 4.5 kg of cyclohexane solvent was added, and 0.075 kg of hydrogenation catalyst (10% Pd / C) was added. The solution was hydrogenated at a hydrogen pressure of 5 MPa and 190°C for 4 h. After the solution was collected, the catalyst was removed by filtration, the solvent was removed by flash evaporation, and the cycloolefin polymer particles were extruded and pelletized. The obtained polymer had a weight average molecular weight Mw of 2.0 × 10 4 , molecular weight distribution is 2.1, and the double bond residual rate is <1%.

[0078] The obtained cycloolefin polymer particles were subjected to performance testing according to the aforementioned testing method, and the performance data thereof are shown in Table 1.

[0079] Example 2

[0080] This embodiment provides a cycloolefin polymer comprising structural units in a molar ratio of 0.43:0.45:0.12.

[0081] The preparation method is as follows: the entire continuous polymerization system is fully purged with nitrogen, 10 kg of a mixed monomer solution (total monomer concentration of 30 wt % in cyclohexane) is added to a monomer preparation tank, wherein the mixed monomer solution is composed of dicyclopentadiene, 2-butyltetracyclododecene (compound T-4, CAS No. 1146980-03-1), and 3-phenylcyclononacarbonyl (compound M-5, CAS No. 40001-70-5) in a molar ratio of 0.43:0.45:0.12. 2.0 g of a chain transfer agent, 1-hexene, is then added to the monomer preparation tank and stirred to mix uniformly to obtain a monomer solution. 0.5 kg of a polymerization catalyst solution (Grubbs second-generation catalyst, cyclohexane) containing 0.03 wt % is added to a catalyst feed tank. The monomer solution was continuously supplied at a rate of 10.2 kg / hr and the polymerization catalyst solution was continuously supplied at a rate of 0.6 kg / hr into a 2 L continuous reactor. Ring-opening polymerization was carried out at 90° C. with stirring for a residence time of 8 min to obtain a copolymer solution, designated as HDTM-2 copolymer solution. The conversion rate of monomer to polymer was >99%. The HDTM-2 copolymer solution was continuously discharged into a polymerization product tank for collection.

[0082] 10.5 kg of the obtained HDTM-2 copolymer solution was added to a 30 L hydrogenation reactor, 4.5 kg of cyclohexane solvent was added, and 0.15 kg of hydrogenation catalyst (10% Pd / C) was added. The solution was hydrogenated at a hydrogen pressure of 4 MPa and 180°C for 3 h. After the reaction, the solution was collected and filtered to remove the catalyst. The solvent was then flashed off and extruded and pelletized to obtain cycloolefin polymer particles. The obtained polymer had a weight average molecular weight Mw of 2.5×10 4 , molecular weight distribution is 2.0, and the residual double bond rate is <1%.

[0083] The obtained cycloolefin polymer particles were subjected to performance testing according to the aforementioned testing method, and the performance data thereof are shown in Table 1.

[0084] Example 3

[0085] This embodiment provides a cycloolefin polymer comprising structural units in a molar ratio of 0.35:0.45:0.2

[0086] The preparation method is as follows: The entire continuous polymerization system is fully purged with nitrogen. 10 kg of a mixed monomer solution (total monomer concentration of 30 wt%, solvent: cyclohexane) is added to a monomer preparation tank. The mixed monomer solution consists of 2-ethyldicyclopentadiene (compound D-9, CAS No. 3034768-82-3), 2-butyltetracyclododecene (compound T-4, CAS No. 1146980-03-1), and 3-phenylcyclooctene (compound M-1, CAS No. 7287-13-0), with a molar ratio of 0.35:0.45:0.2. Then, 3.0 g of a chain transfer agent, 1-hexene, is added to the monomer preparation tank and stirred to mix thoroughly to obtain a monomer solution. 0.5 kg of a 0.03 wt% polymerization catalyst solution (Grubbs second-generation catalyst, solvent: cyclohexane) is added to a catalyst feed tank. The monomer solution was continuously supplied into a 2L continuous reactor at a rate of 29.7 kg / hr and the polymerization catalyst solution was continuously supplied at a rate of 1.5 kg / hr. Ring-opening polymerization was carried out at 100°C with stirring for a residence time of 3 minutes. The copolymer solution was continuously discharged into a polymerization product tank for collection. The conversion rate of the monomer to the polymer was >99%. The obtained copolymer was designated as HDTM-3.

[0087] 10.5 kg of the obtained copolymer HDTM-3 solution was added to a 30 L hydrogenation reactor, 6.5 kg of cyclohexane solvent was added, and an aged nickel acetylacetonate catalyst (2000 ppm in terms of Ni) was added. The mixture was hydrogenated at a hydrogen pressure of 5 MPa and 160°C for 3 h, and then the mixture was collected. After removing the catalyst, the solvent was removed by flash evaporation, and then extruded and pelletized to obtain cycloolefin polymer particles. The obtained polymer had a weight average molecular weight Mw of 1.6×10 4 , molecular weight distribution is 2.2, and the double bond residual rate is <1%.

[0088] The obtained cycloolefin polymer particles were subjected to performance testing according to the aforementioned testing method, and the performance data thereof are shown in Table 1.

[0089] Example 4

[0090] This embodiment provides a cycloolefin polymer comprising structural units in a molar ratio of 0.35:0.45:0.2

[0091] The preparation method is as follows: the entire continuous polymerization system is fully purged with nitrogen. 10 kg of a mixed monomer solution (total monomer concentration of 30 wt % in cyclohexane) is added to a monomer configuration tank. The mixed monomer solution consists of dicyclopentadiene, 2-butyltetracyclododecene, and 3-phenylcyclooctane in a molar ratio of 0.35:0.45:0.2. 3 g of 1-hexene, a chain transfer agent, is then added to the monomer configuration tank and stirred to mix uniformly to obtain a mixed monomer solution. 0.5 kg of a 0.03 wt % polymerization catalyst solution (Grubbs second-generation catalyst, cyclohexane) is added to a catalyst feed tank. 29.7 kg / hr of monomer solution and 1.5 kg / hr of polymerization catalyst solution are continuously fed into a 2L continuous reactor. Ring-opening polymerization is carried out at 100° C. with stirring for 3 minutes. The copolymer solution continuously flows out into a polymerization product tank for collection. The conversion of monomer to polymer is >99%. The resulting copolymer is designated HDTM-4.

[0092] 10.5 kg of the obtained copolymer HDTM-4 solution was added to a 30 L hydrogenation reactor, 4.5 kg of cyclohexane solvent was added, and aged nickel acetylacetonate catalyst (2000 ppm in terms of Ni) was added. The mixture was hydrogenated at a hydrogen pressure of 6 MPa and 130 ° C for 4 hours and then extracted. After removing the catalyst, the solvent was flash evaporated and extruded and pelletized to obtain cycloolefin polymer particles. The obtained polymer had a weight average molecular weight Mw of 1.5×10 4 , molecular weight distribution is 2.3, and the residual double bond rate is <1%.

[0093] The obtained cycloolefin polymer particles were subjected to performance testing according to the aforementioned testing method, and the performance data thereof are shown in Table 1.

[0094] Example 5

[0095] This embodiment provides a cycloolefin polymer comprising structural units A-1 (

[0096]

[0097] The preparation method is as follows: the entire continuous polymerization system is fully nitrogen-purged, and 10 kg of a mixed monomer solution (the total concentration of the mixed monomer is 30 wt % and the solvent is cyclohexane) is added to a monomer configuration tank. The mixed monomer is composed of dicyclopentadiene, tetracyclododecene, and 3-phenylcyclooctane in a molar ratio of 0.35:0.45:0.2. Then, 3.0 g of a chain transfer agent, 1-hexene, is added to the monomer configuration tank and stirred to mix uniformly to obtain the mixed monomer solution. 0.5 kg of a polymerization catalyst solution (Grubbs second-generation catalyst, the solvent is cyclohexane) is added to a catalyst feed tank. 17.8 kg / hr of monomer solution and 0.9 kg / hr of polymerization catalyst solution are continuously supplied to a 2L continuous reactor. Ring-opening polymerization is carried out at 120°C under stirring for 5 minutes. The copolymer solution continuously flows out and is collected in a polymer product tank. The conversion of monomer to polymer is >99%. The resulting copolymer is designated HDTM-5.

[0098] 10.5 kg of the obtained copolymer HDTM-5 solution was added to a 30 L hydrogenation reactor, 4.5 kg of cyclohexane solvent was added, and 0.15 kg of hydrogenation catalyst (60% Ni / SiO2) was added. The mixture was hydrogenated at a hydrogen pressure of 6 MPa and 190°C for 4 hours. After removal of the catalyst, the solvent was removed by flash evaporation and then extruded and pelletized to obtain cycloolefin polymer particles. The obtained polymer had a weight average molecular weight Mw of 1.4×10 4 , molecular weight distribution is 2.1, and the double bond residual rate is <1%.

[0099] Example 6

[0100] This embodiment provides a cycloolefin polymer and a preparation method thereof, which is basically the same as Example 5, except that the molar ratio of dicyclopentadiene, tetracyclododecene, and 3-phenylcyclooctane in the mixed monomer is adjusted to 0.35:0.55:0.10, and other operations and parameters remain unchanged to prepare a cycloolefin polymer.

[0101] Example 7

[0102] This embodiment provides a cycloolefin polymer and a preparation method thereof, which is basically the same as Example 5, except that the molar ratio of dicyclopentadiene, tetracyclododecene, and 3-phenylcyclooctane in the mixed monomer is adjusted to 0.35:0.35:0.30, and other operations and parameters remain unchanged to prepare a cycloolefin polymer.

[0103] Example 8

[0104] This embodiment provides a cycloolefin polymer and a preparation method thereof, which is basically the same as Example 5, except that the molar ratio of dicyclopentadiene, tetracyclododecene, and 3-phenylcyclooctane in the mixed monomer is adjusted to 0.45:0.35:0.2, and other operations and parameters remain unchanged to prepare a cycloolefin polymer.

[0105] Comparative Example 1

[0106] The preparation method was similar to that in Example 1, except that the mixed monomers consisted of dicyclopentadiene and tetracyclododecene in a molar ratio of 0.3:0.55. Other operations and parameters remained unchanged to obtain a cycloolefin polymer. The performance test results are shown in Table 1.

[0107] Comparative Example 2

[0108] The preparation method was similar to that in Example 2, except that the mixed monomers consisted of dicyclopentadiene and 2-butyltetracyclododecene in a molar ratio of 0.43:0.45. Other operations and parameters remained unchanged to obtain a cycloolefin polymer. The performance test results are shown in Table 1.

[0109] Comparative Example 3

[0110] The preparation method was similar to that in Example 1, except that the mixed monomer consisted of tetracyclododecene and 3-phenylcyclododecene in a molar ratio of 0.55:0.15. Other operations and parameters remained unchanged to obtain a cycloolefin polymer. The performance test results are shown in Table 1.

[0111] Comparative Example 4

[0112] The preparation method was prepared by referring to Example 5, except that the molar ratio of dicyclopentadiene, tetracyclododecene, and 3-phenylcyclooctane in the mixed monomers was adjusted to 0.15:0.25:0.6, and other operations and parameters remained unchanged. A polymer was obtained, and the performance test results are shown in Table 1.

[0113] In addition, the performance of two brands of cycloolefin polymers, ZEONEX K26R, an optical material, and ZEONEX 690R, a medical material, both of which are currently mainstream commercial products on the market, were also tested under the same conditions. The results are shown in Table 1.

[0114] Table 1 Physical properties of polymers prepared in the examples of the present invention and comparative examples and properties of commercially available cycloolefin polymers

[0115]

[0116] The cycloolefin polymers prepared in each embodiment of the present invention have significantly improved flexibility compared to commercially available cycloolefin polymers and cycloolefin polymers prepared in comparative examples. The method of the present invention not only imparts excellent mechanical properties to the COP polymer, but also maintains the excellent optical properties and thermal stability of the cycloolefin polymer. The prepared cycloolefin polymers can be widely used in optical lenses, optical films, polarizers, medical treatment, biopharmaceutical packaging materials and other fields.

[0117] Compared with Examples 6-8, Example 5 controls the molar ratio of the three monomers within the preferred range so that the ratio of the molar numbers of the structural unit represented by Formula I, the structural unit represented by Formula II and the structural unit represented by Formula III is within the preferred range, and the high-flexibility cycloolefin polymer obtained in Example 5 has better comprehensive performance.

[0118] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A cycloolefin polymer, characterized in that The cycloolefin polymer comprises structural units shown in the following formulas I, II and III: In Formula I, R1, R2, R7, and R8 are each independently selected from any one of hydrogen, substituted or unsubstituted C1-C20 linear or branched alkyl, and substituted or unsubstituted C3-C20 cycloalkyl; "substituted" means that the H atom in the alkyl or cycloalkyl group is replaced by a halogen atom or a C1-C6 linear or branched alkyl group; In Formula II, n is 0, 1 or 2; R3, R4, R5, and R6 are each independently selected from halogen, unsubstituted or halogenated C1-C20 linear or branched alkyl, unsubstituted or halogenated C3-C20 cycloalkyl, or C6-C20 aryl; R3 and R4 are bonded to each other to form a ring or are not bonded; "substituted" means that the H atom in the alkyl or cycloalkyl group is replaced by a halogen atom or a C1-C6 linear or branched alkyl group; In formula III, p is an integer from 2 to 8; The molar ratio of the structural unit represented by formula I, the structural unit represented by formula II and the structural unit represented by formula III is 5-95:5-95:0.5-50.

2. The cycloolefin polymer according to claim 1, wherein The cycloolefin polymer satisfies one or more of the following AC: A, R1, R2, R7, and R8 are each independently selected from hydrogen or a C1-C6 straight or branched chain alkyl group; B, R3, and R4 are selected from hydrogen, C1-C6 straight or branched chain alkyl; C, R5, and R6 are selected from hydrogen.

3. The cycloolefin polymer according to claim 1 or 2, characterized in that The structural unit shown in Formula I has one of the following structures: ； And / or, the structural unit represented by formula II has one of the following structures: ； And / or, the structural unit represented by formula III has one of the following structures: 。 4. The cycloolefin polymer according to any one of claims 1 to 3, characterized in that The cycloolefin polymer satisfies one or more of the following AC: A, the molar ratio of the structural unit represented by formula I, the structural unit represented by formula II and the structural unit represented by formula III is 30-50:30-55:10-30, more preferably 30-50:45-55:12-20; B. The cycloolefin polymer has a weight average molecular weight of 5,000 to 50,000 and a molecular weight distribution of 1.5 to 3.0; C. The double bond molar content of the cycloolefin polymer is ≤10%, preferably ≤1%.

5. The method for preparing a cycloolefin polymer according to any one of claims 1 to 4, characterized in that: The steps include: Step S1: subjecting a monomer composition comprising monomers represented by Formula A, Formula B, and Formula C to a ring-opening polymerization reaction in the presence of a catalyst and a chain transfer agent to obtain a copolymer: Step S2: hydrogenating the copolymer in the presence of a hydrogenation catalyst to obtain a cycloolefin polymer; In formula A, R1, R2, R7, and R8 are as defined in any one of claims 1 to 4; In formula B, n, R3, R4, R5, and R6 are as defined in any one of claims 1 to 4; In formula C, It represents a straight-linked alkyl group of 3 to 9 carbon atoms.

6. The method for preparing a cycloolefin polymer according to claim 5, wherein The monomer represented by formula A has at least one of the following structures: ； And / or, the monomer represented by formula B has at least one of the following structures: ； And / or, the monomer represented by formula C has at least one of the following structures: 。 7. The method for preparing a cycloolefin polymer according to claim 5 or 6, wherein: In step S1, the monomers represented by formula A, formula B and formula C are mixed with a chain transfer agent and an inert solvent, and then mixed with a polymerization catalyst solution to perform a ring-opening polymerization reaction; Optionally, the inert solvent is selected from at least one of n-hexane, heptane, cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, benzene, toluene, and xylene; Optionally, the mass percentage of the monomer composition to the total mass of the solvent and the monomer composition is 5 to 60%, preferably 15 to 40%; Optionally, the mass percentage concentration of the polymerization catalyst solution is 0.01 to 0.05%.

8. The method for preparing a cycloolefin polymer according to any one of claims 5 to 7, characterized in that: The preparation method satisfies one or more of the following AC: A. The chain transfer agent is selected from at least one of 1-hexene, 1-octene, styrene, and vinyl ether; and / or the ratio of the mass of the chain transfer agent to the total mass of the monomer composition is 1:50-5000; B. The catalyst for the ring-opening polymerization reaction is selected from one or more of a tungsten-based catalyst, a Grubbs series catalyst, and a Schrock series catalyst; and / or the ratio of the mass of the catalyst for the ring-opening polymerization reaction to the total mass of the monomer composition is 1:10,000-100,000; C. The temperature of the ring-opening polymerization reaction is 0 to 200° C., preferably 50 to 150° C.; the time is 1 to 60 minutes, preferably 1 to 20 minutes.

9. The method for preparing a cycloolefin polymer according to any one of claims 5 to 8, characterized in that: The preparation method satisfies one or more of the following AC: A. The hydrogenation catalyst comprises a homogeneous catalyst and / or a heterogeneous catalyst; Preferably, the heterogeneous catalyst is selected from at least one of metal-supported silica, metal-supported alumina, metal-supported titanium oxide, skeletal nickel, and palladium-carbon catalyst; wherein the metal is selected from at least one of nickel, palladium, platinum, rhodium, and ruthenium; more preferably, it is at least one of palladium-carbon catalyst and nickel-supported silica; Preferably, the amount of the heterogeneous catalyst added is 0.25 to 10% of the mass of the reaction solution during the hydrogenation reaction; Preferably, the homogeneous catalyst is selected from at least one of soluble complexes of nickel, titanium, palladium, platinum, rhodium, and ruthenium metals; more preferably, it is a nickel acetylacetonate catalyst; Preferably, the mass of the metal in the homogeneous catalyst is 0.001 to 10% of the mass of the reaction liquid during the hydrogenation reaction; B. The hydrogenation reaction temperature is 80-200°C, the pressure is 1-7 MPa, and the time is 1-10 h; In step C and S2, the copolymer solution is mixed with a solvent and a hydrogenation catalyst and then subjected to a hydrogenation reaction to obtain a cycloolefin polymer.

10. Use of the cycloolefin polymer according to any one of claims 1 to 4 or the cycloolefin polymer prepared by the preparation method according to any one of claims 5 to 9 in optical materials, electronic materials, packaging materials or medical materials.

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