A cycloolefin copolymer based on dicyclopentadiene and a preparation method thereof

Abstract

The present invention provides a cycloolefin copolymer based on dicyclopentadiene and a preparation method thereof. The copolymer has a structure of Formula I; the total number of x accounts for 5 to 40% of the total molar number of all structural units, the total number of y accounts for 20 to 80% of the total molar number of all structural units, and the total number of z accounts for 3 to 40% of the total molar number of all structural units; R1 to R5 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1-6 hydrocarbon group, a phenyl group, a halogen atom, and a substituted or unsubstituted heterocyclic group. The cycloolefin copolymer is mainly a random copolymer of ethylene, dicyclopentadiene, and substituted styrene, and has good thermal-oxidative stability. Compared with the ethylene-dicyclopentadiene copolymer, its strength and toughness are both improved, and its optical properties and the like are maintained. The copolymer can be prepared by terpolymerization of dicyclopentadiene, styrene-based monomers, and ethylene using a rare earth metal complex as the main catalyst and an organic borate as the cocatalyst, etc. The method is simple and is conducive to application.

Description

Technical Field

[0001] The present invention belongs to the technical field of copolymers, and particularly relates to a cycloolefin copolymer based on dicyclopentadiene and a preparation method thereof. Background Art

[0002] Cycloolefin copolymer (COC) is a thermoplastic engineering plastic, generally a copolymer of olefin and cycloolefin obtained by solution polymerization using a single-site catalyst. It has high transparency, low hygroscopicity, good stability and biocompatibility, and has wide applications in the fields of optical devices, packaging, medical devices, etc. At present, the commercially available cycloolefin copolymer that is more widely used is ethylene-norbornene copolymer. Industrially, norbornene is prepared by the Diels-Alder reaction of cyclopentene or dicyclopentadiene with ethylene.

[0003] Dicyclopentadiene is an extract from the C5 fraction of the by-product of ethylene in petroleum cracking. With the continuous expansion of ethylene production capacity in China, the output of the C5 fraction is increasing. However, during the polymerization and storage processes, the cycloolefin copolymer based on dicyclopentadiene is prone to oxidation and crosslinking, so it has not been widely used. Summary of the Invention

[0004] In view of this, the present invention provides a cycloolefin copolymer based on dicyclopentadiene and a preparation method thereof. The cycloolefin copolymer has good thermal-oxidative stability, good optical properties and mechanical properties, etc., and can be simply synthesized using dicyclopentadiene, etc., which will greatly expand the application scope of the cycloolefin copolymer based on dicyclopentadiene.

[0005] The present invention provides a cycloolefin copolymer based on dicyclopentadiene, and this copolymer has a general structural formula of Formula I:

[0006]

[0007] Among them, the total number of x accounts for 5-40% of the total molar number of all structural units, the total number of y accounts for 20-80% of the total molar number of all structural units, and the total number of z accounts for 3-40% of the total molar number of all structural units; R1 to R5 are the same or different groups, each arbitrarily selected from a hydrogen atom, a substituted or unsubstituted C1-6 hydrocarbon group, a phenyl group, a halogen atom, a substituted or unsubstituted heterocyclic group.

[0008] Aiming at the problems existing in the prior art, one of the purposes of the present application is to provide a cycloolefin copolymer with a new structural unit, which has good thermal-oxidative stability without affecting the unique properties of its copolymerized cycloolefins, and it can be copolymerized using dicyclopentadiene, etc., which is beneficial to the application.

[0009] The cycloolefin copolymer described in the embodiments of the present invention is a multi-component copolymer comprising ethylene units, dicyclopentadiene units, and styrene units. The copolymer is a random copolymer, and its structural general formula is shown in Formula I:

[0010]

[0011] In Formula I, the total number of x corresponding to dicyclopentadiene units accounts for 5-40% of the total molar number of all structural units, preferably 6-38%, more preferably 8-38%. y and z correspond to ethylene units and styrene units respectively. The total number of y accounts for 20-80% of the total molar number of all structural units, preferably 22-80%, more preferably 25-80%; the total number of z accounts for 3-40% of the total molar number of all structural units, preferably 4-40%, more preferably 4-38%. In the copolymer, the content of ethylene structural units is 20-80 mol%, the content of dicyclopentadiene structural units is 5 mol% - 40 mol%, and the content of substituted or unsubstituted styrene structural units is 3 mol% to 40 mol%.

[0012] In the embodiments of the present invention, the structure of the cycloolefin copolymer (COC) includes: the dicyclopentadiene structural repeating unit, the styrene structural repeating unit shown below, and the ethylene structural repeating unit (-CH2-CH2-);

[0013]

[0014] Among them, the styrene unit is a substituted or unsubstituted styrene structure, and R1 to R5 on the benzene ring are the same or different groups, each arbitrarily selected from a hydrogen atom (H), a substituted or unsubstituted C1-6 hydrocarbon group, a phenyl group, a halogen atom (such as fluorine, chlorine, bromine, etc.), and a substituted or unsubstituted heterocyclic group (the heterocycle can be a nitrogen heterocycle, an oxygen heterocycle, etc., and the substituted group can be a group containing any one or more of atoms such as oxygen, sulfur, nitrogen, boron, phosphorus, aluminum, halogen, silicon, etc., and the substitution number and position are not limited).

[0015] Preferably, R1 to R5 are each arbitrarily selected from a hydrogen atom, a substituted or unsubstituted C1-5 hydrocarbon group, a fluorine atom (F), and a substituted or unsubstituted nitrogen heterocyclic group, and the substitution number is generally 1-2; unsubstituted means all are H, and the substituted group can specifically be a p-methylthio group, two para-fluorine atom substitutions, 4-(9,10-dihydro-9,9-dimethylacridine), and 4-(2,4,6-triphenyl-1,3,5-triazine).

[0016] In an embodiment of the present invention, the glass transition temperature of the cycloolefin copolymer is 60 to 220 °C, preferably 62 to 217 °C, more preferably 65 to 215 °C, and further 65 to 210 °C. In the embodiment of the present invention, the glass transition temperature Tg is obtained by testing according to the differential scanning calorimetry (DSC) in accordance with the standard of GB / T 29611-2013.

[0017] In an embodiment of the present invention, the number average molecular weight M of the cycloolefin copolymer n is 20,000 to 600,000, preferably 21,000 to 580,000, more preferably 23,000 to 550,000; the molecular weight distribution (M w / M n ) is 1 to 5, preferably 1.02 to 4.8, and more preferably 1.05 to 4.5.

[0018] The cycloolefin copolymer represented by Formula I in the embodiment of the present invention is a random copolymer structure of ethylene, dicyclopentadiene and styrene-based units, and has good thermal oxygen stability. Compared with the ethylene-dicyclopentadiene copolymer, its strength and toughness are both improved, and at the same time, the optical properties and the like are maintained (for example, the transmittance can reach up to 90%).

[0019] The second object of the present invention is to provide a preparation method of the cycloolefin copolymer based on dicyclopentadiene described above, including:

[0020] Using ethylene, dicyclopentadiene and substituted or unsubstituted styrene as monomers, forming a polymerization reaction system with a reaction medium and introducing a catalyst system to initiate a copolymerization reaction to obtain the cycloolefin copolymer represented by Formula I;

[0021] The groups on the benzene ring of the substituted or unsubstituted styrene are each independently selected from hydrogen, substituted or unsubstituted C1-6 hydrocarbon groups, phenyl groups, halogens, and substituted or unsubstituted heterocyclic groups.

[0022] In an embodiment of the present invention, the catalyst system includes: a rare earth metal complex, an organoboron salt compound and an organoaluminum compound.

[0023] Further, the structural formula of the rare earth metal complex is preferably specifically as follows:

[0024]

[0025] In an embodiment of the present invention, the organoboron salt compound is one or more of [Ph3C][B(C6F5)4], [Ph3C][BPh4], [PhNMe2H][BPh4], [PhNMe2H][B(C6F5)4], BPh3, and B(C6F5)3, selected from one or more of [Ph3C][B(C6F5)4], [PhNMe2H][BPh4], [PhNMe2H][B(C6F5)4], and B(C6F5)3, preferably one or more of trityl tetrakis(pentafluorophenyl)borate [Ph3C][B(C6F5)4], [PhNMe2H][B(C6F5)4], and B(C6F5)3.

[0026] Moreover, the organoaluminum compound may be selected from hydrocarbyl-substituted aluminum compounds, including but not limited to diethylaluminum hydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, diphenylaluminum hydride, di-p-tolylaluminum hydride, dibenzylaluminum hydride, phenylethylaluminum, phenyl-n-propylaluminum, p-tolylethylaluminum, p-tolyl-n-propylaluminum, p-tolylisopropylaluminum, benzylethylaluminum, benzyl-n-propylaluminum, benzylisopropylaluminum, ethyldialuminum hydride, butyldialuminum hydride, isobutyldialuminum hydride, octyldialuminum hydride, pentyldialuminum hydride, diethylaluminum ethoxide, dipropylaluminum ethoxide, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, triphenylaluminum, tri-p-tolylaluminum, tribenzylaluminum, ethyldiphenylaluminum, ethyldi-p-tolylaluminum, ethyldibenzylaluminum, diethylphenylaluminum, diethyl-p-tolylaluminum, and diethylbenzylaluminum; preferably one or more of diisobutylaluminum hydride, diethylaluminum hydride, trioctylaluminum, triisobutylaluminum (Al i Bu3), and trimethylaluminum.

[0027] In an embodiment of the present invention, the above catalytic components can be dissolved in a solvent to obtain a catalyst solution. First, dicyclopentadiene, ethylene, substituted or unsubstituted styrene, and a reaction medium are added to a reaction vessel, and then the catalyst solution is added to carry out a copolymerization reaction.

[0028] In addition to dicyclopentadiene and ethylene, the selection of styrene monomers (which can be referred to as the third monomers) in the embodiments of the present invention is very crucial. The groups on the benzene ring are each independently selected from hydrogen, substituted or unsubstituted C1-6 hydrocarbon groups, phenyl groups, halogens, substituted or unsubstituted heterocyclic groups. The specific structures are as described above. For example, unsubstituted styrene, p-methylthio styrene, 2,5-dimethyl styrene, p-fluoro styrene, 4-(9,10-dihydro-9,9-dimethyl acridine) styrene, 4-(2,4,6-triphenyl-1,3,5-triazine) styrene are used. Further, in the embodiments of the present invention, styrene with an electron-withdrawing substituent at the para position is preferably selected, which has the best effect, specifically in terms of polymerization activity. For example, a random copolymer of ethylene-dicyclopentadiene-fluorostyrene can be prepared.

[0029] In a preferred embodiment of the present application, the catalytic system is a combination of the above-mentioned rare earth metal metallocene catalyst / rare earth metal constrained geometry catalyst and a cocatalyst. Among them, the rare earth metal complex is the main catalyst and the organic borate is the cocatalyst. Through coordination catalysis, the copolymerization of ethylene, dicyclopentadiene and styrene monomers is carried out to prepare the cycloolefin copolymer. In some embodiments, the molar ratio of the rare earth complex, the organoaluminum compound and the organic borate in the catalytic system is 1:2:1.

[0030] The reaction medium involved in the embodiments of the present invention is selected from one or more of aliphatic saturated hydrocarbons, aromatic hydrocarbons, aryl halides and cycloalkanes, and can be an alkane and / or a halogenated hydrocarbon. The reaction medium is preferably selected from at least one of pentane, hexane, toluene, xylene, heptane, cyclohexane, cycloheptane, dichloromethane, chlorobenzene, o-dichlorobenzene and dichloroethane. Among them, specific examples of the straight-chain alkane include but are not limited to at least one of pentane, hexane and heptane, and can also be a cycloalkane such as cyclohexane, or an aromatic hydrocarbon such as toluene and xylene. Specific examples of the halogenated hydrocarbon include but are not limited to at least one of dichloromethane, chlorobenzene, o-dichlorobenzene and dichloroethane.

[0031] During the copolymerization reaction, the pressure of ethylene in the reaction system can be 1-12 atm, preferably 1-11 atm, more preferably 1-10 atm, such as using 1 atm of ethylene; the monomer concentrations can be 0.01-3.0 mol / L, preferably 0.02-2.7 mol / L, more preferably 0.05-2.5 mol / L. Exemplarily, 20 mmol of dicyclopentadiene, 10-20 mmol of styrene-based monomer and 20 mL of toluene (other reaction media can also be used) can be added to a 75 mL polymerization flask. After being fully purged with nitrogen, 1.0 atm of ethylene is charged into it under vigorous stirring to make it reach a saturated state in the toluene solution; the prepared catalyst solution is taken out of the glove box and quickly added to the polymerization reaction system to initiate catalytic polymerization. During the polymerization process, the monomer and the catalyst are in the same reaction flask. In the examples of this application, the dosage and concentration of the catalyst remain unchanged, and only the monomer concentration is changed. The change in monomer concentration will affect the polymerization activity and the properties of the polymer.

[0032] The conditions of the copolymerization reaction described in the embodiments of the present invention generally include: the temperature of the reaction system can be -20-80 °C, preferably -10-70 °C, more preferably 0-60 °C, and further 30-50 °C; the reaction time is 0.01-12 h, preferably 0.02-11 h, more preferably 0.03-10 h, such as 10 min, 15 min, 20 min, 60 min and longer times, etc. After polymerizing for a certain time, 20 mL of acidified methanol solution can be immediately added to terminate the reaction in the embodiments of the present invention; finally, a large amount of ethanol is added to separate the copolymer, and the polymerization product is vacuum dried at 40-50 °C until the weight of the copolymer does not change, and the cycloolefin copolymer is obtained.

[0033] In summary, this application provides a cycloolefin copolymer with a structure shown in Formula I and a preparation method thereof. It mainly introduces substituted or unsubstituted styrene-based compounds into the ethylene-dicyclopentadiene copolymer molecular chain in a ternary copolymerization manner. The substituted styrene structural units of the present invention are dispersed in the polymer chain, which can separate the dicyclopentadiene structural units and reduce the activity of the remaining double bonds, thereby improving the thermal-oxidative stability of the cycloolefin copolymer based on dicyclopentadiene. In addition, the mechanical strength and elongation at break of the copolymer are both improved, and the optical properties are maintained. At the same time, the preparation method provided by the examples of this application has high activity and wide universality, which greatly expands the application scope of the cycloolefin copolymer based on dicyclopentadiene and has important significance. Description of the Drawings

[0034] Figure 1 For the copolymer sample prepared in Example 1 of the present invention 1 1H NMR spectrum;

[0035] Figure 2 1H NMR spectrum of the copolymer sample prepared in Example 1 of the present invention 13 13C NMR spectrum;

[0036] Figure 3 DSC spectrum of the copolymer sample prepared in Example 1 of the present invention;

[0037] Figure 4 Mechanical property curves of the copolymer samples prepared in Examples 3-5 of the present invention;

[0038] Figure 5 Transmittance curves of the copolymer samples prepared in Examples 3-5 of the present invention. Detailed implementation manners

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0040] To better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the cycloolefin copolymer and its preparation method described in the present invention. The protection scope of the present invention is not limited by the following embodiments.

[0041] Among them, the raw materials used in the following embodiments of the present invention are all commercially available products.

[0042] Example 1

[0043] In a glove box, a rare earth complex of the structure of Formula 1 (10 μmol), Al i Bu3 (20 μmol) and triphenylcarbenium tetrakis(pentafluorophenyl)borate [Ph3C][B(C6F5)4] (10 μmol) were dissolved in 5 mL of toluene to obtain a catalyst solution. 20 mmol of dicyclopentadiene, 20 mmol of p-methylthio styrene and 20 mL of toluene were added to a 75 mL polymerization flask. After being thoroughly purged with nitrogen, 1.0 atm of ethylene was introduced into it under vigorous stirring to make it reach a saturated state in the toluene solution. The above catalyst solution was taken out of the glove box and quickly added to the polymerization reaction system at 40 °C to initiate catalytic polymerization; after 20 min, 20 mL of acidified methanol solution was immediately added to terminate the reaction; finally, a large amount of ethanol was added to separate the copolymer, and the copolymer was dried in vacuo at 40 °C until the weight of the copolymer did not change, obtaining a cycloolefin copolymer.

[0044] Example 2

[0045] In a glove box, dissolve the rare earth complex of formula 3 (10 μmol), Al i Bu3 (20 μmol) and triphenylcarbenium tetrakis(pentafluorophenyl)borate [Ph3C][B(C6F5)4] (10 μmol) in 5 mL of toluene to obtain a catalyst solution. Add 20 mmol of dicyclopentadiene, 20 mmol of 2,5-dimethylstyrene and 20 mL of toluene to a 75 mL polymerization flask. After purging thoroughly with nitrogen, charge 1.0 atm of ethylene into it under vigorous stirring to saturate it in the toluene solution. Take out the above catalyst solution from the glove box and quickly add it to the polymerization reaction system at 40 °C to initiate polymerization; after 10 min, immediately add 20 mL of acidified methanol solution to terminate the reaction; finally, add a large amount of ethanol to separate the copolymer, and vacuum dry the copolymer at 40 °C until the weight of the copolymer no longer changes to obtain a cycloolefin copolymer.

[0046] Example 3

[0047] In a glove box, dissolve the rare earth complex of formula 3 (10 μmol), Al i Bu3 (20 μmol) and triphenylcarbenium tetrakis(pentafluorophenyl)borate [Ph3C][B(C6F5)4] (10 μmol) in 5 mL of toluene to obtain a catalyst solution. Add 10 mmol of dicyclopentadiene, 20 mmol of p-fluorostyrene and 20 mL of toluene to a 75 mL polymerization flask. After purging thoroughly with nitrogen, charge 1.0 atm of ethylene into it under vigorous stirring to saturate it in the toluene solution. Take out the above catalyst solution from the glove box and quickly add it to the polymerization reaction system at 40 °C to initiate polymerization; after 10 min, immediately add 20 mL of acidified methanol solution to terminate the reaction; finally, add a large amount of ethanol to separate the copolymer, and vacuum dry the copolymer at 40 °C until the weight of the copolymer no longer changes to obtain a cycloolefin copolymer.

[0048] Example 4

[0049] In a glove box, dissolve the rare earth complex of formula 3 (10 μmol), Al iBu3 (20 μmol) and triphenylcarbenium tetrakis(pentafluorophenyl)borate [Ph3C][B(C6F5)4] (10 μmol) were dissolved in 5 mL of toluene to obtain a catalyst solution. 20 mmol of dicyclopentadiene, 20 mmol of p-fluorostyrene and 20 mL of toluene were added to a 75 mL polymerization flask. After being thoroughly purged with nitrogen, 1.0 atm of ethylene was introduced into it under vigorous stirring to saturate it in the toluene solution. The above catalyst solution was taken out of the glove box and quickly added to the polymerization reaction system at 40 °C to initiate polymerization; after 10 min, 20 mL of acidified methanol solution was immediately added to terminate the reaction; finally, a large amount of ethanol was added to separate the copolymer, and the copolymer was dried under vacuum at 40 °C until the weight of the copolymer no longer changed, obtaining a cycloolefin copolymer.

[0050] Example 5

[0051] In the glove box, a rare earth complex of formula 3 structure (10 μmol), Al i Bu3 (20 μmol) and triphenylcarbenium tetrakis(pentafluorophenyl)borate [Ph3C][B(C6F5)4] (10 μmol) were dissolved in 5 mL of toluene to obtain a catalyst solution. 20 mmol of dicyclopentadiene, 10 mmol of p-fluorostyrene and 20 mL of toluene were added to a 75 mL polymerization flask. After being thoroughly purged with nitrogen, 1.0 atm of ethylene was introduced into it under vigorous stirring to saturate it in the toluene solution. The above catalyst solution was taken out of the glove box and quickly added to the polymerization reaction system at 40 °C to initiate polymerization; after 10 min, 20 mL of acidified methanol solution was immediately added to terminate the reaction; finally, a large amount of ethanol was added to separate the copolymer, and the copolymer was dried under vacuum at 40 °C until the weight of the copolymer no longer changed, obtaining a cycloolefin copolymer.

[0052] Example 6

[0053] In the glove box, a rare earth complex of formula 3 structure (10 μmol), Al iBu3 (20 μmol) and triphenylcarbenium tetrakis(pentafluorophenyl)borate [Ph3C][B(C6F5)4] (10 μmol) were dissolved in 5 mL of toluene to obtain a catalyst solution. 20 mmol of dicyclopentadiene, 10 mmol of 4-(9,10-dihydro-9,9-dimethylacridine)styrene and 20 mL of toluene were added to a 75 mL polymerization flask. After purging thoroughly with nitrogen, 1.0 atm of ethylene was introduced into it under vigorous stirring to saturate it in the toluene solution. The above catalyst solution was taken out of the glove box and quickly added to the polymerization reaction system at 40 °C to initiate the polymerization. After 10 min, 20 mL of acidified methanol solution was immediately added to terminate the reaction. Finally, a large amount of ethanol was added to separate the copolymer, and the copolymer was dried under vacuum at 40 °C until the weight of the copolymer did not change, and a cycloolefin copolymer was obtained.

[0054] Example 7

[0055] In the glove box, a rare earth complex of formula 3 structure (10 μmol), Al i Bu3 (20 μmol) and triphenylcarbenium tetrakis(pentafluorophenyl)borate [Ph3C][B(C6F5)4] (10 μmol) were dissolved in 5 mL of toluene to obtain a catalyst solution. 20 mmol of dicyclopentadiene, 1 mmol of 4-(2,4,6-triphenyl-1,3,5-triazine)styrene and 20 mL of toluene were added to a 75 mL polymerization flask. After purging thoroughly with nitrogen, 1.0 atm of ethylene was introduced into it under vigorous stirring to saturate it in the toluene solution. The above catalyst solution was taken out of the glove box and quickly added to the polymerization reaction system at 40 °C to initiate the polymerization. After 10 min, 20 mL of acidified methanol solution was immediately added to terminate the reaction. Finally, a large amount of ethanol was added to separate the copolymer, and the copolymer was dried under vacuum at 40 °C until the weight of the copolymer did not change, and a cycloolefin copolymer was obtained.

[0056] Example 8

[0057] In the glove box, a rare earth complex of formula 7 structure (10 μmol), Al i3 mmol of Bu3 (20 μmol) and 1 mmol of triphenylcarbonium tetrakis(pentafluorophenyl)borate [Ph3C][B(C6F5)4] (10 μmol) were dissolved in 5 mL of toluene to obtain a catalyst solution. 10 mmol of dicyclopentadiene, 20 mmol of styrene and 20 mL of toluene were added to a 75 mL polymerization flask. After being thoroughly purged with nitrogen, 1.0 atm of ethylene was introduced into it under vigorous stirring to saturate it in the toluene solution. The above catalyst solution was taken out of the glove box and quickly added to the polymerization reaction system at 40 °C to initiate polymerization; after 15 min, 20 mL of acidified methanol solution was immediately added to terminate the reaction; finally, a large amount of ethanol was added to separate the copolymer, and the copolymer was dried in vacuo at 40 °C until the weight of the copolymer did not change, obtaining a cycloolefin copolymer.

[0058] For the contents of each component such as ethylene (E), dicyclopentadiene (DCPD), and para-fluorostyrene (FSt) in the cycloolefin copolymer (styrenic monomers are denoted as St), they were calculated according to the 1 1H NMR spectrum of the copolymer measured at 110 °C in C6D2Cl4, and were calculated using the following formulas respectively:

[0059] f E =(I 0.8-3ppm -20I 5.7ppm -3I 6-7ppm )÷(I 6-7ppm +4I 0.8-3ppm -12I 5.7ppm );

[0060] f DCPD =8I 5.7ppm ÷(I 6-7ppm +4I 0.8-3ppm -12I 5.7ppm );

[0061] f St =4I 6-7ppm ÷(I 6-7ppm +4I 0.8-3ppm -12I 5.7ppm ).

[0062] For the cycloolefin copolymer prepared in the examples of the present invention, its glass transition temperature was detected by differential scanning calorimetry (DSC) according to the standard of GB / T 29611-2013 "Determination of glass transition temperature of raw rubber - Differential scanning calorimetry (DSC)".

[0063] For polymers such as ethylene-fluorostyrene prepared in the examples of the present invention, using polystyrene as the standard substance, gel permeation chromatography (GPC) was carried out at 40 °C with THF as the mobile phase to test its number average molecular weight (M n ) and molecular weight distribution (Mw / M n )。The Polymer dispersity index (PDI) is the polymer dispersity index, which is used to describe the polymer molecular weight distribution.

[0064] Determination of the tensile strength and elongation at break of the copolymer: The tensile strength and elongation at break of the copolymer were determined by a universal mechanical tester according to GB / T 528-1998.

[0065] The relevant test results are as follows: The structural characterization results of the obtained product are shown in Figure 1 、 Figure 2 , Figure 1 is the 1 1H NMR spectrum of the sample, Figure 2 and 13 is the

[0066] And Figure 3 is the DSC spectrum of the copolymer sample described above. For specific results, see Table 1.

[0067] Table 1 Preparation conditions and related properties of the products of the examples of the present invention

[0068]

[0069] The cycloolefin copolymer based on dicyclopentadiene prepared in the examples of the present invention has a glass transition temperature of 65-210 °C and a molecular weight distribution of 1.05-4.5.

[0070] Figure 4 is the mechanical property curve of the copolymer samples prepared in Examples 3-5 of the present invention. In Example 3, the tensile strength is 40.1 Mpa and the elongation at break is 6.6%. In Example 4, the tensile strength is 41.0 Mpa and the elongation at break is 9.9%. In Example 5, the tensile strength is 42.5 Mpa and the elongation at break is 8.2%. Figure 5 is the transmittance curve of the copolymer samples prepared in Examples 3-5. In the wavelength range of 400-800 nm, the transmittance is above 80%, and the highest can reach 90%.

[0071] Taking the rare earth complex 3 as the catalytic system as an example, when the third monomer is styrene, almost no product can be obtained after polymerization for ten minutes. However, when 4-(9,10-dihydro-9,9-dimethylacridine)styrene is used as the third monomer, 3.24 g of product can be obtained in 10 minutes (Example 6), greatly improving the polymerization activity. The rare earth complex 3 catalyzes the copolymerization of ethylene and dicyclopentadiene to obtain an alternating copolymer, which has poor stability and will crosslink even when heated in air or stored at room temperature. For the terpolymer obtained by using the rare earth complex 3 in the present invention, the styrene-based monomer is uniformly dispersed in the polymer chain, and the double bond is inertized through steric hindrance and p-π conjugation, so that the obtained terpolymer has good thermal-oxidative stability.

[0072] As can be seen from the above examples, the cycloolefin copolymer based on dicyclopentadiene provided by the present invention has high thermal-oxidative stability. The mechanical strength and elongation at break of the copolymer are both improved, and good optical properties are maintained. At the same time, the preparation method provided in this application has high activity and wide universality, which greatly expands the application scope of the cycloolefin copolymer based on dicyclopentadiene.

[0073] The description of the above examples is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0074] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a cycloolefin copolymer, characterized in that, Comprising: Using ethylene, dicyclopentadiene and substituted styrene as monomers, forming a polymerization reaction system with a reaction medium and introducing a catalyst system to initiate a copolymerization reaction to obtain a cycloolefin copolymer shown in Formula I; The substituted styrene is 4-(9,10-dihydro-9,9-dimethylacridine)styrene; Formula I; Wherein, the total number of x accounts for 8-38% of the total molar number of all structural units; the total number of y accounts for 25-80% of the total molar number of all structural units; the total number of z accounts for 3-40% of the total molar number of all structural units; R1 to R5 are the same or different groups, respectively selected from a hydrogen atom, a 9,10-dihydro-9,9-dimethylacridine group; The glass transition temperature of the cycloolefin copolymer is 60-220 °C; the number average molecular weight of the cycloolefin copolymer is 23,000-550,000; the molecular weight distribution of the cycloolefin copolymer is 1.05-4.5; The catalyst system includes: a rare earth metal complex, an organoborate compound and an organoaluminum compound; the structural formula of the rare earth metal complex is specifically as follows: 。 2. The method for preparing a cycloolefin copolymer according to claim 1, wherein The organoborate compound is one or more of [Ph3C][B(C6F5)4], [Ph3C][BPh4], [PhNMe2H][BPh4], [PhNMe2H][B(C6F5)4], BPh3 and B(C6F5)3; the organoaluminum compound is selected from hydrocarbyl-substituted aluminum compounds.

3. The method for preparing a cycloolefin copolymer according to claim 2, characterized in that, The organoaluminum compound is selected from one or more of diethylaluminum hydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, diphenylaluminum hydride, di-p-tolylaluminum hydride, dibenzylaluminum hydride, phenylethylaluminum hydride, phenyl-n-propylaluminum hydride, p-tolylethylaluminum hydride, p-tolyl-n-propylaluminum hydride, p-tolylisopropylaluminum hydride, benzylethylaluminum hydride, benzyl-n-propylaluminum hydride, benzylisopropylaluminum hydride, ethyldialuminum hydride, butyldialuminum hydride, isobutyldialuminum hydride, octyldialuminum hydride, pentyldialuminum hydride, diethylaluminum ethoxide, dipropylaluminum ethoxide, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, triphenylaluminum, tri-p-tolylaluminum, tribenzylaluminum, ethyldiphenylaluminum, ethyldi-p-tolylaluminum, ethyldibenzylaluminum, diethylphenylaluminum, diethylp-tolylaluminum and diethylbenzylaluminum.

4. The method for preparing a cycloolefin copolymer according to claim 3, wherein The organoaluminum compound is one or more of diisobutylaluminum hydride, diethylaluminum hydride, trioctylaluminum, triisobutylaluminum and trimethylaluminum.

5. The method for preparing a cycloolefin copolymer according to claim 1, characterized in that, During the copolymerization reaction process, the pressure of ethylene in the polymerization reaction system is 1-12 atm; the monomer concentrations are respectively 0.01-3.0 mol / L.

6. The method for preparing a cycloolefin copolymer according to claim 5, wherein During the copolymerization reaction process, the pressure of ethylene in the polymerization reaction system is 1-11 atm; the monomer concentrations are respectively 0.02-2.7 mol / L.

7. The method for preparing a cycloolefin copolymer according to claim 6, wherein During the copolymerization reaction process, the pressure of ethylene in the polymerization reaction system is 1-10 atm; the monomer concentrations are respectively 0.05-2.5 mol / L.

8. The method for preparing a cycloolefin copolymer according to claim 1, characterized in that, The temperature of the copolymerization reaction is -20-80 °C; the time is 0.01-12 h.

9. The method for preparing a cycloolefin copolymer according to claim 8, wherein The temperature of the copolymerization reaction is -10~70 °C; the time is 0.02~11 h.

10. The method for preparing a cycloolefin copolymer according to claim 9, wherein, The temperature of the copolymerization reaction is 0~60 °C; the time is 0.03~10 h.

11. The method for preparing a cycloolefin copolymer according to claim 1, wherein The reaction medium is selected from one or more of aliphatic saturated hydrocarbons, aromatic hydrocarbons, aryl halides and cycloalkanes.

12. The method for preparing a cycloolefin copolymer according to claim 11, wherein The reaction medium is selected from at least one of pentane, hexane, toluene, xylene, heptane, cyclohexane, cycloheptane, dichloromethane, chlorobenzene, o-dichlorobenzene and dichloroethane.

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