Ethylene / alpha-olefin copolymerization modifier and its homogeneous catalytic system

Abstract

The application discloses an ethylene / alpha-olefin copolymerization modification aid and a homogeneous catalytic system thereof, and belongs to the field of olefin polymerization. The catalytic system is composed of the following components: component A is a main catalyst component; component B is a cocatalyst component; component C is an ultradry solvent component; and component D is a copolymerization modification aid component. The active centers of the copolymerization modification aid component D and the main catalyst component A exist in the form of coordination complexation, supramolecular assembly or electrostatic adsorption. The copolymerization modification aid component D can significantly reduce the amount of the cocatalyst component B. In particular, the copolymerization modification aid component D can slow down the poisoning inactivation rate of the main catalyst component A, prolong the catalytic life of the main catalyst component A, strengthen the activated reduction degree of the metal active center element M of the main catalyst, improve the high-temperature thermal stability of the catalytic system, realize stable heat release of the polymerization reaction and mass transfer directional regulation of ethylene and alpha-olefin comonomers, and has excellent technical and economic benefits.

Description

TECHNICAL FIELD

[0001] The present technology relates to the field of olefin polymerization and catalysts, in particular to an ethylene / alpha-olefin copolymerization modifier and its homogeneous catalyst system. The catalyst system in the present invention is particularly suitable for olefin copolymerization, which has good polymerization activity and high temperature thermal stability in copolymerization, stable polymerization kinetics, and can significantly reduce the amount of cocatalyst. In particular, the introduced copolymerization modifier can effectively "coat" the active centers of the main catalyst, making the metal active center elements of the homogeneous catalyst system more easily reduced, producing new reduced valence active centers, while also regulating the polymerization mass transfer process of the comonomer, weakening the attack of small molecules and toxic substances on the active center, and playing a role in slowing down the deactivation of the ethylene / alpha-olefin copolymerization homogeneous catalyst and extending the service life of the main catalyst. BACKGROUND

[0002] Polyolefin elastomer (POE) is a kind of polyolefin material produced by random copolymerization of ethylene and high-carbon alpha-olefin catalyzed by metallocene catalyst. In the POE chain segment structure, the polyethylene chain crystalline region acts as a physical crosslinking point for the resin phase, while the alpha-olefin plays a role in weakening the polyethylene chain crystalline region. The polyethylene chain crystalline region makes the product have typical plastic properties, while the alpha-olefin makes the product have the properties of elastomer, so the product POE has both plasticity and elasticity. At present, the high-temperature solution polymerization process is the main production method of polyolefin elastomer. On the one hand, high polymerization temperature is beneficial to reducing the viscosity of the material in the reactor, ensuring good heat transfer and mass transfer in the reactor; on the other hand, high-temperature solution polymerization is beneficial to accurately controlling the molecular chain structure of the polymerization product.

[0003] Metallocene catalysts need to use expensive, completely dependent on imports and severely insufficient in production capacity methylaluminoxane (MAO) or modified methylaluminoxane (MMAO) as a decontaminant and cocatalyst for the polymerization system in the production of high-end polyolefins. Therefore, how to improve the activity of the main catalyst and reduce the amount of cocatalyst is crucial to reducing production costs and overcoming the "neck" problem of aluminoxane. In addition, although the polymerization activity and comonomer insertion ability of traditional constrained geometry metallocene (CGC) catalysts are strong, the catalysts have a short service life and are easily poisoned and deactivated. Chinese patent CN201010577990 discloses a preparation method of a constrained geometry metallocene chromium catalyst. The catalyst system uses alkylaluminoxane, alkylaluminum, halogenated alkylaluminum or their mixture as a cocatalyst, and no longer needs to use a large amount of methylaluminoxane or expensive [Ph3C] + [B(PhF5)4] 4-, greatly reducing the cost of the metallocene catalyst system. However, the above-mentioned catalyst system has a short catalytic life and a low comonomer insertion rate when used for olefin polymerization. Chinese Patent CN2019109097920 discloses a new type of metallocene catalyst system. Although the catalyst system has high copolymerization activity and long catalyst life, the catalyst needs to use expensive MAO as a cocatalyst during the olefin polymerization process, greatly increasing the cost of the metallocene catalyst system.

[0004] In summary, the ethylene / alpha-olefin high-temperature solution polymerization process still has some deficiencies in the catalyst: (1) the single active center metallocene catalyst has high activity, but the catalyst life is short and is easily poisoned and deactivated; (2) the comonomer insertion rate in the polymerization product is low; (3) the amount of cocatalyst used is large and expensive alkyl aluminoxane or modified alkyl aluminoxane is used, greatly increasing the production cost and the ash content of the product, and reducing the economic benefit of the product. SUMMARY

[0005] In view of the deficiencies of the existing catalyst, the applicant found through research that introducing a copolymerization modification additive into the reaction system can obtain a catalyst system with high activity and long life. The catalyst system not only greatly reduces the amount of cocatalyst used, changes the polymerization kinetics of ethylene / alpha-olefin copolymerization, makes the metal active center element of the homogeneous catalyst system more easily reduced, produces new reduced valence active centers, and improves the high-temperature thermal stability of the catalyst system. In addition, the catalyst system can regulate the mass transfer process of ethylene and alpha-olefin in the copolymerization reaction, solve the problem of easy poisoning and deactivation of traditional metallocene catalyst systems, and prolong the catalyst life.

[0006] One of the purposes of the present application is to provide an ethylene / alpha-olefin copolymerization modification additive. The ethylene / alpha-olefin copolymerization modification additive is selected from one or more of a silicon halide organic compound, a siloxane organic compound, an ether compound, a silazane compound, a silane coupling agent, and a fluorosilane compound. The main structure of the ethylene / alpha-olefin copolymerization modification additive is one or more of a cage type, a semi-cage type, a cone type, and a ladder structure. The organic group in the long-chain molecular chain of the ethylene / alpha-olefin copolymerization modification additive is selected from C 10 -C 300 alkyl, C 10 -C 300 cycloalkyl, C 10 -C 300 unsaturated hydrocarbon group, C 10 -C 300 aryl, C 10 -C 300 aralkyl, C 10 -C 300 aliphatic hydrocarbon group, C10 -C 300 alkoxy, C 10 -C 300 alicyclic group, C 10 -C 300 alicyclic alkoxy and C 10 -C 300 aryloxy or C 10 -C 300 aliphatic hydrocarbon group, C 10 -C 300 alkoxy, C 10 -C 300 alicyclic group, C 10 -C 300 alicyclic alkoxy, C 10 -C 300 aryloxy or C 10 -C 300 aromatic hydrocarbon group, the number of long-chain molecular chains in the copolymerization modification aid component D is between 1-20.

[0007] The ethylene / alpha-olefin copolymerization modification aid can be complexed with the active center of the main catalyst, changing the density and distribution of the active center, thereby creating different polymerization microenvironments for ethylene / alpha-olefin copolymerization and realizing directional control of the mass transfer of the comonomer. On the other hand, the aid has long chains that can play a role in encapsulating the catalyst, "covering" the active center and hindering the attack of small molecules and toxic substances on the active center, slowing down the toxic effect and prolonging the service life of the catalyst. In addition, another advantage of the present application is that a homogeneous ethylene / alpha-olefin copolymerization catalyst system capable of significantly reducing the amount of expensive cocatalyst is constructed. The copolymerization modification aid can reduce the amount of cocatalyst by 25%-95%, which can bring excellent economic benefits.

[0008] The present application provides a homogeneous catalyst system for ethylene / alpha-olefin copolymerization, which comprises the following components: a main catalyst component A, a cocatalyst component B, an ultra-dry solvent component C, and a copolymerization modification aid component D (i.e. the aforementioned ethylene / alpha-olefin copolymerization modification aid); wherein the copolymerization modification aid component D is selected from one or more of silicon halide-based organic compounds, siloxane-based organic compounds, ether compounds, silazane-based compounds, silane coupling agents, and fluorosilane-based compounds, the main structure of the copolymerization modification aid component D is one or more of a cage type, a semi-cage type, a cone type and a ladder type, and the organic group in the long-chain molecular chain of the copolymerization modification aid component D is selected from one or more of C 10 -C 300 aliphatic hydrocarbon group, C 10 -C 300 alkoxy, C 10 -C 300 alicyclic group, C 10 -C 300 alicyclic alkoxy, C 10 -C 300 aryloxy or C 10 -C 300 aromatic hydrocarbon group, the number of long-chain molecular chains in the copolymerization modification aid component D is between 1-20.

[0009] As a preferred embodiment of the present application, the configuration method of the ethylene / α-olefin copolymerization modified homogeneous catalyst system: ethylene / α-olefin copolymerization modifier component D and main catalyst component A are dissolved in super-dry solvent component C, and kept stirring for at least 2h under nitrogen atmosphere or inert gas environment, wherein the main catalyst component A and the copolymerization modifier component D are in coordination complex or electrostatic adsorption form at a certain molar ratio, and the cocatalyst component B is separately placed in an inert gas environment for standby. The obtained homogeneous catalyst system is used for ethylene / α-olefin copolymerization process.

[0010] As a preferred embodiment of the present application, the ethylene / α-olefin copolymerization process based on the above homogeneous catalyst system is as follows: the polymerization reactor is baked for 2-4h under vacuum and at least 100℃ environment, after the baking of the reactor is completed, a proper amount of polymerization solvent E and α-olefin F are added and stirred for at least 10min, the reactor is raised to the reaction temperature T, a certain amount of cocatalyst component B is added to remove impurities and prepare for subsequent activation of the main catalyst, and finally a certain amount of the configured homogeneous catalyst system is added, and then ethylene is immediately introduced for copolymerization reaction, the polymerization pressure is P, and after the reaction time t, the polymerization product is discharged and subjected to product characterization.

[0011] As a preferred embodiment of the present application, the addition of the copolymerization modifier component D can significantly prolong the life of the main catalyst, stabilize the heat release of the polymerization reaction, and realize the directional regulation of the mass transfer of ethylene and α-olefin comonomers.

[0012] As a preferred embodiment of the present application, the addition of the copolymerization modifier component D can significantly prolong the life of the main catalyst, stabilize the heat release of the polymerization reaction, and realize the directional regulation of the mass transfer of ethylene and α-olefin comonomers.

[0013] As a preferred embodiment of the present application, the copolymerization modifier component D can be one or more of the following cage-type siloxane organic compounds general formula (I), (II), (III):

[0014]

[0015] The copolymerization modifier component D can also be one or more of the following semi-cage-type siloxane organic compounds general formula (IV), (V), (VI):

[0016]

[0017] The copolymerization modifier component D can also be one or more of the following special siloxane organic compounds general formula (VII), (VIII):

[0018]

[0019]

[0020] As a preferred embodiment in the present application, the procatalyst A can be formed by complexing the central metal element M with a ligand (I) or a ligand (II) of the following formula. The central metal element M is selected from one or more of Ti(III), Ti(IV), Ti(V), V(IV), V(V), Fe(II), Fe(III), Co(II), Co(VI), Ni(II), Cu(I), Cu(II), Zn(II), Zr(II), Zr(III), Ru(II), Ru(III), Rh(II), Rh(III), Pd(II), Pd(IV), Cr(IV), Zr(IV), Hf(III), Hf(IV).

[0021]

[0022] The substituents R in the above general formula (I) to general formula (VII) 1 -R 16 The substituents R1-R6 in the ligand (I) and the ligand (II) are organic groups (hetero elements such as O, N, P, S, Ge, etc. can exist in the main chain) having the same structure or different structures with the number of carbon atoms in the main chain being between 10 and 300. Preferably, R 1 -R 16 The substituents R1-R6 can be independently selected from C 10 -C 300 alkyl, C 10 -C 300 cycloalkyl, C 10 -C 300 unsaturated hydrocarbon group, C 10 -C 300 aryl (including linear, branched and cyclic phenyl), C 10 -C 300 aralkyl, C 10 -C 300 epoxy, C 10 -C 300 aryloxy, C 10 -C 300 aliphatic hydrocarbon group and derivatives thereof, and halogen-substituted C 10 -C 300 alkyl, C 10 -C 300 cycloalkyl, C 10 -C 300 unsaturated hydrocarbon group, C 10 -C 300 aryl (including linear, branched and cyclic phenyl), C 10 -C 300 aralkyl, C 10 -C 300epoxy, C 10 -epoxy, C 300 -epoxy, C 10 -epoxy, C 300 -epoxy, C 10 -epoxy, C 300 -epoxy, C 10 -epoxy, C 300 -epoxy, C 10 -epoxy, C 300 -epoxy, C 10 -epoxy, C 300 -epoxy, C 10 -epoxy, C 300 -epoxy, C 10 -epoxy, C 300 -epoxy, C 10 -epoxy, C 300 -epoxy, C 10 -epoxy, C 300 -epoxy, C 1 -epoxy, C 16 R1-R6 can independently be preferably one or more of n-decyl, 1-methyl-n-decyl, 2-methyl-n-decyl, 3-methyl-n-decyl, cyclodecyl, 1-methylcyclodecyl, 2-methylcyclodecyl, 1-decenyl, 2-decenyl, cyclodecadienyl, methylcyclodecadienyl, 1,2-dimethylcyclodecadienyl, tetramethylcyclodecadienyl, pentamethylcyclodecadienyl, tetramethyl-n-propylcyclodecadienyl, tetramethylphenylcyclodecadienyl, ethylcyclodecadienyl, n-propylcyclodecadienyl, isopropylcyclodecadienyl, n-butylcyclodecadienyl, t-butylcyclodecadienyl, alkenyl, tetramethylphenylcyclodecadienyl, stearyl group, anilino, p-methoxymethylidene, p-methoxybenzylidene, p-methoxybenzylidene, methoxyanilino, piperonyloyl, p-methoxybenzoyl, p-methoxybenzoyl, p-methoxybenzoyl, p-methoxybenzylidene, p-methoxybenzylidene, p-methoxybenzylidene, cacodyl, borneol, camphor diacyl, hexadecyl, docosyl, hexacosyl, eleostearoyl, dodecyl, polystyryl.

[0023] As a preferred embodiment in the present application, the cocatalyst component B is one or more of alkyl aluminum, alkyl aluminoxane and organoboronate, wherein the organic group is one or more of saturated or unsaturated straight chain, branched chain or cyclic chain, and the number of molecular chains is between 1 and 20. The general structure of alkyl aluminum is AlR 10 , R n AlX 10-n or R 10 Al 10 X 10 (R is C 10 -epoxy, C300 The alkyl group, where X is a halogroup, n = 0, 1, 2, 3); wherein the alkyl aluminum is preferably one or more of trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, triisohexylaluminum, trioctylaluminum, and triphenylaluminum; and the alkyl aluminum chloride is preferably sesquimethylaluminum chloride, dichlorodimethylaluminum, dichloromethylaluminum, sesquiethylaluminum chloride, dichlorodiethylaluminum, dichloroethylaluminum, dichlorodipropylaluminum, dichloropropylaluminum, and dichlorodimethylaluminum. One or more of the following: isopropylaluminum, dichloroisopropylaluminum, sesqui-n-butylaluminum chloride, dichlorodi-n-butylaluminum, dichlorodi-n-butylaluminum, sesqui-isobutylaluminum chloride, diisobutylaluminum chloride, dichloroisobutylaluminum, sesqui-n-hexylaluminum chloride, dichlorodi-n-hexylaluminum, sesqui-isohexylaluminum chloride, diisohexylaluminum chloride, dichloroisohexylaluminum, sesqui-octylaluminum chloride, dichlorodioctylaluminum, and dichlorooctylaluminum; alkylaluminoxanes containing R(-Al(-R)-O). n The structure is -Al-R2), where n is an integer, and each R can be independently C. 10 -C 300 Alkyl, aryl, alkoxy, and aryloxy groups, and optionally two or more R groups may be linked together to obtain a specified cyclic structure, i.e., the two R groups may be oxygen bridges between two aluminum atoms, preferably one or more of methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, n-propylaluminoxane, isopropylaluminoxane, n-butylaluminoxane, isobutylaluminoxane, neodecylaluminoxane, n-hexylaluminoxane, and n-octylaluminoxane; organoboronide B(C 10 X5) 10 BR n X 10-n In the equation, X is a halogen and R is a carbon. 10 -C 300The hydrocarbon group, wherein the hydrocarbon group is a saturated or unsaturated straight-chain, branched, or cyclic chain; R is preferably methyl, ethyl, propyl, isopropyl, 1-butyl, 2-butyl, 1-isobutyl, 2-isobutyl, propenyl, 1-butenyl, 2-butenyl, 1-methylpropenyl, cyclopropyl, 1-methylcyclopropyl, 2-methylcyclopropyl, 1-ethylcyclopropyl, 2-ethylcyclopropyl, 1-propylcyclopropyl, 2-propylcyclopropyl, cyclobutyl, 1-methylcyclobutyl, 2-methylcyclobutyl, 1-ethylcyclobutyl, 2-ethylcyclobutyl, 1-propylcyclobutyl, 2-propylcyclobutyl, cyclodecyl, 1-methylcyclodecyl, 2-methylcyclodecyl, 1-ethylcyclodecyl, 2-ethylcyclodecyl, 1-propylcyclodecyl, 2-propylcyclodecyl The organoboronide is preferably one or more of the following: cyclodecyl, cyclohexyl, 1-methylcyclohexyl, 2-methylcyclohexyl, 1-ethylcyclohexyl, 2-ethylcyclohexyl, 1-propylcyclohexyl, and 2-propylcyclohexyl;

[0024] In a preferred embodiment of the present invention, the ultra-dry solvent component C is selected from C4-C. 16 Alkanes (including straight-chain and branched chains), C4-C 16 Cycloalkanes, C5-C 300 Aromatic hydrocarbons, C5-C 300 Epoxy hydrocarbons, C6-C 300 Aromatic hydrocarbons, C5-C 10 One or more of alicyclic hydrocarbons and their derivatives and paraffin oil are used, and the main chain of the ultra-dry solvent component C may contain heterogeneous elements such as O, N, P, S, and Ge; preferably, the ultra-dry solvent component C is one or more of toluene, xylene, n-pentane, isopentane, neopentane, cyclopentane, n-hexane, cyclohexane, n-heptane, methylcyclohexane, octane, isooctane, tetrahydrofuran, and diethyl ether, more preferably toluene and n-hexane.

[0025] As a preferred embodiment of the present application, the ratio of the organoaluminum cocatalyst and the main catalyst component A is 1-2000, preferably 1.1-500, in terms of the molar ratio of Al element to M element (active center element of the main catalyst); preferably, the ratio of the cocatalyst component B and the main catalyst component A is 1-2000, preferably 1.1-500, in terms of the molar ratio of B element to M element; preferably, the main catalyst is added in an amount of 1-200 μmol / L in terms of the molar concentration of M element in the super-dry solvent component; the polymerization reaction temperature is 0-250°C, preferably 50-200°C; the polymerization reaction pressure is 0.3-10 MPa; the polymerization reaction stirring speed is 50-400 r / min, preferably 150-250 r / min.

[0026] The present application also provides an ethylene / α-olefin copolymerization method based on the ethylene / α-olefin homogeneous catalytic system, wherein the copolymerization reactor is baked in a vacuum and an environment above 100°C to remove moisture and oxygen in the reactor, polymerization solvents E and F are added and stirred, a certain amount of the prepared homogeneous catalytic system is added, and then olefin monomer ethylene is introduced to start the copolymerization reaction, the polymerization pressure is P, the polymerization temperature is T, and the reaction time is t, after which the polymerization product is discharged. The polymerization reaction temperature is selected from 0-250°C, preferably 50-200°C, and the polymerization pressure is selected from 0-50 MPa, preferably 0.3-10 MPa.

[0027] The gain effect brought by the ethylene / α-olefin copolymerization modifier and the homogeneous catalytic system thereof is as follows:

[0028] (1) The copolymerization modifier component D and the main catalyst component A form a homogeneous solution in the super-dry solvent component C through coordination complexation or electrostatic adsorption. Based on the "catalyst encapsulation" strategy, the long chain of the copolymerization modifier component D "coats" the active center of the main catalyst, spatially hinders the attack of toxic substances on the active center, inhibits the deactivation reaction, and prevents impurity molecules from occupying the active sites to form invalid active sites; in addition, the hindering effect of the long chain will increase the time required for the contact and complexation of the comonomer and the active center to some extent, thereby prolonging the polymerization time. In summary, the introduction of the copolymerization modifier component D can significantly improve the catalytic life of the main catalyst component A, and the homogeneous catalytic system containing the copolymerization modifier component D can improve the polymerization catalytic life by 4 times compared to the homogeneous catalytic system of the pure catalyst component A.

[0029] (2) The copolymerization modification auxiliary component D and the main catalyst component A form a homogeneous catalyst system through coordination complexation or electrostatic adsorption. Compared with the homogeneous catalyst system before modification, the metal active center element of the modified homogeneous catalyst system is more easily activated and reduced by the cocatalyst component B. In addition, the modified homogeneous catalyst system produces new active centers of reduced valence, which is not possessed by the homogeneous catalyst system before modification. In summary: because the modified catalyst system is more easily reduced, there are more effective active centers in the polymerization microenvironment, and the new active centers of reduced valence also play a polymerization role. The synergistic effect of the two valence active centers prolongs the service life of the catalyst and improves the copolymerization activity.

[0030] (3) The long chain of the copolymerization modification auxiliary component D can isolate the polymerization microenvironment into several regions, avoid the aggregation of metal active centers into clusters in the polymerization microenvironment, and form local temperature hotspots. The copolymerization modification auxiliary component D can act as an in-situ heat diffusion medium to effectively eliminate temperature hotspots, solve the problem of unstable heat release in the polymerization reaction, and avoid the "flying temperature" phenomenon.

[0031] (4) The copolymerization modification auxiliary component D greatly reduces the amount of traditional methylaluminoxane or modified methylaluminoxane used as a cocatalyst in the ethylene / α-olefin copolymerization process, reduces the [Al] / [M] molar ratio from 1000-2000 to 1.1-500, significantly reduces the production cost, and breaks the limitation of high-priced methylaluminoxane cocatalyst on the industrial application of ethylene / α-olefin copolymerization catalyst.

[0032] In summary, the copolymerization modification auxiliary component and the homogeneous catalyst system thereof provided by the present application significantly improve the high-temperature thermal stability and catalytic life of the main catalyst, slow down the deactivation of the catalyst, reduce the amount of expensive cocatalyst, improve the polymerization kinetics stability, and have good catalytic performance and application value. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a schematic diagram of the "catalyst encapsulation" effect of the copolymerization modification auxiliary D in the present application.

[0034] Figure 2 It is the polymerization kinetics curve of Example 1 and Comparative Example 1 in the present application.

[0035] Figure 3 It is the temperature change curve of Example 1 and Comparative Example 1 in the present application.

[0036] Figure 4 It is the electron paramagnetic resonance result comparison of the homogeneous catalyst system before activation of Example 1 and Comparative Example 1 in the present application.

[0037] Figure 5Comparison of electron paramagnetic resonance results for homogeneous catalytic systems of Example 1 and Comparative Example 1 of the present application after activation by aluminoxane and borane. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present application will be described in more detail below, and the present application will be further explained and described. The examples are only used to illustrate the present application, and do not limit the scope of the present application. In the following, the materials, reagents and instruments used in the examples are not specified by the manufacturer, and are all purchased from the market; the experimental methods used in the examples are conventional methods unless otherwise specified; the concentrations in the examples are molar concentrations unless otherwise specified.

[0039] The catalytic activity of ethylene / α-olefin copolymerization reaction was determined by quantitative analysis of each component in the reaction product, liquid phase components were analyzed by internal standard method and gas chromatography, and solid phase products were analyzed by vacuum drying and weighing method.

[0040] Performance test

[0041] Segment structure analysis:

[0042] The performance of the polymer material is first determined by the microstructure of the polymer segment. The analysis of the segment structure is extremely important for the design of the material. The average composition of the comonomer in the copolymer can be determined by high-temperature nuclear magnetic carbon spectrum (C-NMR). 13

[0043] Molecular weight and molecular weight distribution test:

[0044] The molecular weight (Mw, Mn) and molecular weight distribution (PDI) of the polymer can be determined by high-temperature gel chromatography (GPC). A 0.1-0.3 wt% polymer solution is prepared at 160°C with 1,2,4-trichlorobenzene as the solvent, and a narrow-distribution polystyrene (PS) is used as a standard sample for determination.

[0045] Melt index:

[0046] The melt quality flow rate of the material can be determined by a melt index instrument. The flow characteristics of the test material are determined at a temperature of 190°C and a standard load of 2.16 kg.

[0047] Density:

[0048] The density of the polymer can be determined by a density gradient column. After the melt index sample is degassed, it is cut into 1 mm cylinders and thrown into the density gradient column. After the 1 mm cylinders are stable, the density gradient column scale value is read, and the density value of the polymer is calculated by computer program.

[0049] Example 1:

[0050] The copolymerization modifier aid D component is shown as formula 1-1, wherein R​1 2 3 4 5 6 7 8 is n-decyl group, the ligand structure of the procatalyst component A is shown as formula 1-2, the central metal atom is Ti(IV), R1, R2, R3, R4, R5, R6 are n-decyl groups.

[0051]

[0052] The homogeneous catalytic system was configured: 0.25 μmol of the copolymerization modifier auxiliary D and 10 μmol of the procatalyst component A were taken in 5 mL of toluene solution to form a homogeneous solution, and the homogeneous solution was kept under 250 rpm stirring for at least 2 h, and the above configuration operations were all operated in the glove box filled with inert gas. The obtained homogeneous catalytic system was reserved for copolymerization.

[0053] The 1 L copolymerization reactor was baked at high temperature (above 130°C) and under vacuum for at least 2 h, and at least 20 times of inert gas was used for replacement during the baking. After the baking was completed, 350 mL of polymerization solvent hexane was added into the polymerization kettle, followed by the addition of 90 mL of 1-octene, then 2 μmol of methylaluminoxane as the cocatalyst component and 10 μmol of borane were added, stirring for at least 2 min to remove impurities in the polymerization kettle, and finally 2 μmol of the homogeneous catalytic system (the molar amount of the homogeneous catalytic system was calculated based on the content of the procatalyst component A) was added. Ethylene was introduced for copolymerization reaction, the polymerization pressure was 4.0 MPa, the polymerization temperature was 135°C, the polymerization product was high-pressure sprayed, and the product performance was analyzed. The polymerization product analysis results are shown in Table 1.

[0054] Example 2:

[0055] The copolymerization modifier auxiliary D component is shown as formula 2-1, wherein R 1 2 3 4 is n-decyl group, the ligand structure of the procatalyst component A is shown as formula 2-2, the central metal atom is Co(II), R1, R2, R3, R4, R5 are n-decyl groups.

[0056]

[0057] The homogeneous catalytic system configuration process is the same as that of Example 1, the polymerization experiment is the same as that of Example 1, and the polymerization product analysis results are shown in Table 1.

[0058] Example 3:

[0059] ​​​​​​​​​​Copolymerizing modifier component D is shown in Formula 3-1, wherein R 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 R 9 R 10 The ligand structure of the main catalyst component A is shown in Formula 3-2, with the central metal atom being Cu(II) and R1, R2, R3, R4, and R5 being n-decyl groups.

[0060]

[0061] The homogeneous catalytic system configuration process is the same as in Example 1, the polymerization experiment is the same as in Example 1, and the analysis results of the polymerization product are shown in Table 1.

[0062] Example 4:

[0063] Copolymerizing modifier component D is shown in Formula 4-1, wherein R 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 R 9 R 10 The ligand structure of the main catalyst component A is shown in Formula 4-2, with the central metal atom being Zr(Ⅲ) and R1, R2, R3, R4, and R5 being n-decyl groups.

[0064]

[0065] The homogeneous catalytic system configuration process is the same as in Example 1, the polymerization experiment is the same as in Example 1, and the analysis results of the polymerization product are shown in Table 1.

[0066] Example 5:

[0067] Copolymerizing modifier component D is shown in Formula 5-1, wherein R 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 R 9 R 10n-decyl, the ligand structure of the main catalyst component A is shown in formula 5-2, the central metal atom is Rh(III), R1, R2, R3, R4, R5 are n-decyl.

[0068]

[0069] The homogeneous catalytic system configuration process is the same as that of Example 1, the polymerization experiment is the same as that of Example 1, and the polymerization product analysis results are shown in Table 1.

[0070] Example 6:

[0071] The copolymerization modifier D component is shown in formula 6-1, wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 is n-decyl, the ligand structure of the main catalyst component A is shown in formula 6-2, the central metal atom is Hf(IV), R1, R2, R3, R4, R5 are n-decyl.

[0072]

[0073] The homogeneous catalytic system configuration process is the same as that of Example 1, the polymerization experiment is the same as that of Example 1, and the polymerization product analysis results are shown in Table 1.

[0074] Example 7:

[0075] The copolymerization modifier D component is shown in formula 7-1, wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 is n-decyl, the ligand structure of the main catalyst component A is shown in formula 7-2, the central metal atom is Hf(IV), R1, R2, R3, R4, R5 are n-decyl.

[0076]

[0077] The homogeneous catalytic system configuration process is the same as that of Example 1, the polymerization experiment is the same as that of Example 1, and the polymer product analysis results are shown in Table 1.

[0078] Example 8:

[0079] The copolymerization modifier aid D component is shown as formula 8-1, wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 is n-tetracontyl, and the ligand structure of the main catalyst component A is shown as formula 8-2, the central metal atom is Hf (IV), R1, R2, R3, R4, and R5 are n-decyl.

[0080]

[0081] The homogeneous catalytic system configuration process is the same as that of Example 1, the polymerization experiment is the same as that of Example 1, and the polymer product analysis results are shown in Table 1.

[0082] Example 9:

[0083] The copolymerization modifier aid D component is shown as formula 9-1, wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 is n-tetracontyl, and the ligand structure of the main catalyst component A is shown as formula 9-2, the central metal atom is Ti (IV), R1, R2, R3, R4, R5, and R6 are n-decyl.

[0084]

[0085] The homogeneous catalytic system is configured: 0.25 μmol of the copolymerization modifier aid D shown as formula 9-1 and 10 μmol of the main catalyst component A are taken in 5 mL of toluene solution to form a homogeneous solution, and the homogeneous solution is kept under 250 rpm stirring state for at least 2 h, and the above configuration operations are all operated in the glove box filled with inert gas. The obtained homogeneous catalytic system is reserved for copolymerization.

[0086] A 1L copolymerization reactor was baked at high temperature (above 130℃) and under vacuum for at least 2 hours, during which it was purged with inert gas at least 20 times. After baking, 350mL of polymerization solvent hexane was added to the polymerization reactor, followed by 90mL of 1-octene, then 2μmol of cocatalyst component methylaluminoxane and 10μmol of borane. The mixture was stirred for at least 2 minutes to remove impurities from the polymerization reactor. Finally, 2μmol of homogeneous catalytic system (the molar amount of the homogeneous catalytic system was calculated based on the content of main catalyst component A) was added, and ethylene was introduced to carry out the copolymerization reaction. The polymerization pressure was 4.0MPa, and the polymerization temperature was 60℃. The polymerization product was sprayed under high pressure and the product performance was analyzed. The analysis results of the polymerization product are shown in Table 1.

[0087] The differences between Examples 10-18 and Example 9 are shown in the table below. The copolymerization modifier component D, the ligand structure of the main catalyst component A, the central metal atom and group, the process of configuring the homogeneous catalytic system, and the polymerization process are all the same as in Example 9. The analysis results of the polymerization products are shown in Table 1.

[0088]

[0089]

[0090] Comparative Example 1:

[0091] The ligand structure of the main catalyst component A is shown in Formula 19-1, with the central metal atom being Ti(Ⅳ) and R1, R2, R3, R4, R5, and R6 being positive tetradecyl groups.

[0092]

[0093]

[0094] Preparation of homogeneous catalytic system: Take 10 μmol of main catalyst component A and add it to 5 mL of toluene solution to form a homogeneous solution. Keep the homogeneous solution under stirring at 250 rpm for at least 2 h. All the above preparation operations are carried out in a glove box filled with inert gas. The resulting homogeneous catalytic system is reserved for copolymerization for later use.

[0095] A 1L copolymerization reactor was baked at high temperature (above 130℃) and under vacuum for at least 2 hours, during which it was purged with inert gas at least 20 times. After baking, 350mL of polymerization solvent heptane was added to the polymerization reactor, followed by 90mL of comonomer 1-octene, then 2μmol of cocatalyst component methylaluminoxane and 10μmol of borane. The mixture was stirred for at least 2 minutes to remove impurities from the polymerization reactor. Finally, 2μmol of homogeneous catalytic system (the molar amount of the homogeneous catalytic system was calculated based on the content of main catalyst component A) was added, and ethylene was introduced to carry out the copolymerization reaction. The polymerization pressure was 4.0MPa and the polymerization temperature was 135℃. The polymerization product was sprayed under high pressure and the product performance was analyzed. The analysis results of the polymerization product are shown in Table 1.

[0096] Comparative Example 2:

[0097] The ligand structure of the main catalyst component A is shown in Formula 20-1, with the central metal atom being Co(II) and R1, R2, R3, R4, and R5 being tetradecyl groups.

[0098]

[0099] Preparation of homogeneous catalytic system: Take 10 μmol of main catalyst component A and add it to 5 mL of toluene solution to form a homogeneous solution. Keep the homogeneous solution under stirring at 250 rpm for at least 2 h. All the above preparation operations are carried out in a glove box filled with inert gas. The resulting homogeneous catalytic system is reserved for copolymerization for later use.

[0100] A 1L copolymerization reactor was baked at high temperature (above 130℃) and under vacuum for at least 2 hours, during which it was purged with inert gas at least 20 times. After baking, 350mL of polymerization solvent heptane was added to the polymerization reactor, followed by 90mL of comonomer 1-octene, then 2μmol of cocatalyst component methylaluminoxane and 10μmol of borane. The mixture was stirred for at least 2 minutes to remove impurities from the polymerization reactor. Finally, 2μmol of homogeneous catalytic system (the molar amount of the homogeneous catalytic system was calculated based on the content of main catalyst component A) was added, and ethylene was introduced to carry out the copolymerization reaction. The polymerization pressure was 4.0MPa and the polymerization temperature was 135℃. The polymerization product was sprayed under high pressure and the product performance was analyzed. The analysis results of the polymerization product are shown in Table 1.

[0101] Table 1 Summary of analytical results for products from examples and comparative examples

[0102]

[0103]

[0104] The above are the analysis and characterization results of the polymerization systems of Examples 1-18 and Comparative Examples 1-2, as well as the ethylene / α-olefin copolymers, combined with the appendix. Figures 1-5It can be seen that:

[0105] (1) By comparing the polymerization activity of Comparative Examples 1-8 and Comparative Examples 1-2 and the polymerization kinetics curves of the catalyst system, it is found that the polymerization activity of the catalyst system introduced with the ethylene copolymerization modifier is 4 times that of the original catalyst system, and the polymerization time is increased by about 4 times, which indicates that the ethylene copolymerization modifier plays a role of "catalyst encapsulation", effectively prolonging the catalyst life and slowing down the deactivation reaction caused by small molecules and toxic substances. Figure 2

[0106] (2) By comparing the polymerization activity of Comparative Examples 1-8 and Comparative Examples 1-2 and the polymerization kinetics curves of the catalyst system, it is found that the polymerization activity of the catalyst system introduced with the ethylene copolymerization modifier is 4 times that of the original catalyst system, and the polymerization time is increased by about 4 times, which indicates that the ethylene copolymerization modifier plays a role of "catalyst encapsulation", effectively prolonging the catalyst life and slowing down the deactivation reaction caused by small molecules and toxic substances. Figure 3 The polymerization temperature change curve shows that the polymerization temperature of the catalyst system introduced with the ethylene copolymerization modifier is about 15℃ higher than that of the original catalyst system, and the polymerization exothermic process is more stable, indicating that the ethylene copolymerization modifier can effectively improve the high-temperature thermal stability of the catalyst system.

[0107] (3) By comparing the catalytic activity, 1-octene insertion rate and polymerization time of Comparative Examples 1, Example 9 and Example 10, it can be found that the temperature of 135℃ is the preferred reaction temperature of ethylene / α-olefin.

[0108] (4) By comparing the polymerization activity and polymerization time of Comparative Examples 1, Example 13 and Comparative Example 1, it can be found that the molecular chain length of the ethylene copolymerization modifier has a significant influence on the catalytic performance: the longer the molecular chain of the ethylene copolymerization modifier, the better the encapsulation effect on the catalyst system, which can more effectively prolong the catalyst life and increase the polymerization activity.

[0109] (5) By comparing the polymerization activity and polymerization time of Comparative Examples 1, Example 14 and Example 15, it can be found that the number of long-chain molecules of the ethylene copolymerization modifier also has an important influence on the catalytic performance: the more the number of long-chain molecules of the ethylene copolymerization modifier, the better the encapsulation effect on the catalyst system, which can more effectively protect the active center, regulate the mass transfer process of ethylene and comonomer, and increase the polymerization activity and catalyst life.

[0110] (6) By comparing the EPR spectra of Comparative Examples 1-8, it can be found that the introduction of the ethylene copolymerization modifier promotes the methylation process of the active center, which is reflected in the appearance of double peaks in the electron paramagnetic resonance spectrum (EPR) with g factors of 1.98 and 1.99, respectively, indicating the generation of new active centers of trivalent titanium, and the synergistic effect of the two valence states of the active center prolongs the service life of the catalyst and improves the copolymerization activity. Figure 1 Figure 4 Figure 5 It is found that the introduction of the ethylene copolymerization modifier promotes the methylation process of the active center, which is reflected in the appearance of double peaks in the electron paramagnetic resonance spectrum (EPR) with g factors of 1.98 and 1.99, respectively, indicating the generation of new active centers of trivalent titanium, and the synergistic effect of the two valence states of the active center prolongs the service life of the catalyst and improves the copolymerization activity.

[0111] ​​​(7) By comparing the polymerization activity of Example 16 and Comparative Example 1, it can be found that under the condition of the same polymerization time and similar copolymer yield, the amount of the cocatalyst, especially the expensive methylaluminoxane, consumed in the polymerization process is reduced by half, indicating that the ethylene copolymerization modifier can greatly reduce the amount of expensive cocatalyst;

[0112] (8) By comparing the copolymer product properties of Example 17 and Example 18, it can be found that under the same reaction time, by changing the polymerization solvent and the content of the comonomer, the polymerization mass transfer process can be regulated to obtain copolymer products with different physical parameters (comonomer insertion rate, molecular weight, melt index and density, etc.).

[0113] In addition to the above examples, the present application also has other various embodiments, which are described more specifically and in detail, but should not be understood as limiting the scope of the present patent. Those skilled in the art can make certain changes and improvements according to the present application without departing from the concept and essence of the present application, and these changes should all belong to the protection scope of the claims of the present application.

Claims

1. An ethylene / α-olefin copolymerization modifier characterized by comprising: The ethylene / alpha-olefin copolymerization modifier is a siloxane-based organic compound, the main structure of the ethylene / alpha-olefin copolymerization modifier is one or more of a cage type, a semi-cage type, a cone type and a ladder type, the ethylene / alpha-olefin copolymerization modifier contains long-chain molecular chains, and the organic groups in the long-chain molecular chains are selected from one or more of C 10 -C 300 alkyl, C 10 -C 300 cycloalkyl, C 10 -C 300 unsaturated hydrocarbon groups, C 10 -C 300 aryl, C 10 -C 300 aralkyl, C 10 -C 300 alkoxy and C 10 -C 300 aryloxy, and the number of long-chain molecular chains in the ethylene / alpha-olefin copolymerization modifier is between 1 and 20.

2. An ethylene / alpha-olefin copolymerization homogeneous catalytic system characterized in that, The homogeneous catalytic system comprises the following components: a main catalyst component A, a cocatalyst component B, an ultradry solvent component C, and the ethylene / α-olefin copolymerization modifier component D of claim 1; after the addition of the copolymerization modifier component D to the homogeneous catalytic system, the central metal element in the main catalyst component A activated by the cocatalyst component B exhibits a double peak in the normal temperature electron paramagnetic resonance test, and the magnetic field strength is between 345-365 mT, and the g factor is between 1.96-1.98 and 1.98-2.10, respectively.

3. The homogeneous ethylene / alpha-olefin copolymerization catalyst system of claim 2, wherein, The configuration method of the homogeneous catalytic system is as follows: the copolymerization modifier component D and the main catalyst component A are dissolved in the ultradry solvent component C, and are kept in a stirring state for at least 30 min under an inert gas environment to obtain a standby, wherein the main catalyst component A and the copolymerization modifier component D exist in the form of coordination complexation, electrostatic adsorption, or molecular accumulation, and the cocatalyst component B is placed in an inert gas environment for standby.

4. The ethylene / alpha-olefin homogeneous catalytic system according to claim 2 or 3, characterized in that, The central metal element of the main catalyst component A is selected from one or more of Ti(III), Ti(IV), Ti(V), V(IV), V(V), Fe(II), Fe(III), Co(II), Co(VI), Ni(II), Cu(I), Cu(II), Zn(II), Zr(II), Zr(III), Ru(II), Ru(III), Rh(II), Rh(III), Pd(II), Pd(IV), Cr(IV), Zr(IV), Hf(III), and Hf(IV).

5. The ethylene / alpha-olefin homogeneous catalytic system according to claim 2 or 3, characterized in that, The cocatalyst component B is one or more of alkyl aluminum, alkyl aluminoxane, modified alkyl aluminoxane, and borides, wherein the organic group in the cocatalyst component B is selected from one or more of saturated or unsaturated straight chain, branched chain, or cyclic chain, and the number of molecular chains of the organic group in the cocatalyst component B is between 1-20.

6. The ethylene / alpha-olefin homogeneous catalytic system according to claim 2 or 3, characterized in that, The ultradry solvent component C is selected from one or more of alkanes, cycloalkanes, and benzene.

7. The ethylene / alpha-olefin homogeneous catalytic system according to claim 3, wherein The concentration of the copolymerization modifier component D in the ultradry solvent component C in the homogeneous catalytic system is 0.05-500 μmol / mL; the concentration of the main catalyst component A in the ultradry solvent component C is 1-20000 μmol / mL; the molar ratio of the copolymerization modifier component D to the main catalyst component A is 1:500-500:1; and the molar ratio of the main catalyst component A to the cocatalyst component B is 1:1-1:2000.

8. A process for the copolymerization of ethylene with an α-olefin based on the homogeneous catalytic system of ethylene / α-olefin of claim 3, characterized in that, The copolymerization reactor is baked under vacuum and an environment above 100℃ to remove moisture and oxygen in the reactor, polymerization solvents E and F are added and stirred, and then the configured homogeneous catalytic system is added, followed by the introduction of olefin monomers to start the copolymerization reaction, the polymerization pressure is P, the polymerization temperature is T, and the reaction time is t, after which the polymerization product is discharged; the polymerization reaction temperature is selected from 0-250℃, and the polymerization pressure is selected from 0-50 MPa.

9. The method of claim 8, wherein, The polymerization solvent E is selected from one or more of alkanes, cycloalkanes, and benzene; the polymerization solvent F is selected from one or more of α-olefins, and the ultradry solvent component C and the polymerization solvent E can be the same component or different components.

10. An ethylene / α-olefin copolymer product produced by the process of claim 8 or 9, characterized in that, The insertion rate of the comonomer alpha-olefin is 0.1 to 30 mol%; the copolymer molecular weight is 10,000 to 300,000 g / mol; the copolymer density is 0.850 to 0.920 g / cm 3 .

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