Supported catalyst system and application thereof in olefin polymerization

Abstract

The invention discloses a supported catalyst system and an application thereof in olefin polymerization, the supported catalyst system comprises the following raw materials by mass fraction: a bridged metallocene compound, a non-bridged metallocene compound, a carrier and an activator, the structure of the bridged metallocene compound is shown as a formula A, the structural formula A is shown as a formula B, and the structural formula B is shown as a formula C; the structure of the unbridged metallocene compound is as shown in a formula B in the specification. The supported catalyst system provided by the invention has the advantages that the polymer formed by polymerization has higher mechanical properties, and the melt strength, toughness, melt-flow ratio and the like of the polymer can be remarkably improved, so that the processability of the polymer is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of olefin polymerization catalyst preparation technology, specifically to a supported catalyst system and its application in olefin polymerization. Background Technology

[0002] Olefin polymerization catalysts are catalysts used for olefin polymerization, typically based on a combination of a cyclopentadienyl transition metal compound as a catalyst precursor and an activator (usually an aluminoxane or an activator containing a noncoordinate anion); for example, metallocene catalyst systems, which include a metallocene catalyst, an activator, and an optional support.

[0003] Currently, when using olefin polymerization catalysts to catalyze the formation of polymers from ethylene, bimodal polyethylene and unimodal polyethylene can be obtained through different catalyst systems. Bimodal and unimodal polyethylene are two completely different polymers. Unlike unimodal polyethylene, bimodal polyethylene is prepared using two different catalysts to produce high-molecular-weight polyethylene and low-molecular-weight polyethylene respectively, thereby improving processing performance, but at the same time sacrificing some mechanical properties. Therefore, compared to bimodal polyethylene, unimodal polyethylene has advantages in tensile strength and tear strength, but its melt strength, toughness, and melt flow ratio are significantly lower, resulting in poorer processing performance. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that the currently disclosed unimodal polyethylene has problems with poor melt strength, toughness and melt flow ratio, and thus provides a supported catalyst system to improve the above problems and its application in olefin polymerization.

[0005] A supported catalyst system, by mass fraction, comprises a bridged metallocene compound, an unbridged metallocene compound, a support, and an activator. The structure of the bridged metallocene compound is shown in Formula A. Formula A: , M1 is a Group 4 metal. R1-R4 are each independently a hydrogen, alkoxy, or C1-C40 substituted or unsubstituted hydrocarbon group. R5 and R6 are each independently hydrogen, alkoxy, C1-C40 substituted or unsubstituted hydrocarbon group, -R20-SiR'3 or -R20-CR'3, wherein R20 is hydrogen or a C1-C4 hydrocarbon group, and R' is each independently a C1-C20 substituted or unsubstituted hydrocarbon group, and at least one of R' is not H. R7 is a C1-C40 substituted or unsubstituted hydrocarbon group, alkoxy group, or halogen. R8 represents oxygen, nitrogen, phosphorus, and sulfur. T is a bridging group, C or Si. X are each anionic ligands that are independently monovalent; The structure of the unbridged metallocene compound is shown in Formula B. Formula B: , M2 is a Group 4 metal. R9-R18 are each independently a hydrogen, alkoxy, or C1-C40 substituted or unsubstituted hydrocarbon group. Y is an independent monovalent anion ligand.

[0006] Among them, Group 4 metals, which are also Group IVB or Group 4 transition metals, include: titanium (Ti), zirconium (Zr), and hafnium (Hf).

[0007] R5 and R6 are each independently hydrogen, alkoxy, C1-C20 substituted or unsubstituted hydrocarbon group, -R20-SiR'3 or -R20-CR'3; And / or, R9-R18 are each independently hydrogen, alkoxy, or C1-C20 substituted or unsubstituted hydrocarbon groups; And / or, the monovalent anionic ligand is selected from chlorine, bromine, methyl, ethyl and fluorine.

[0008] The bridging metallocene compounds include SiMe2 (Me4Cp) ( t Bu-N)TiCl2, SiMe2 (Me4Cp)(iPr-N)TiCl2, SiMe2 (Me4Cp) (adamantane-N)TiCl2, SiMe2 (Me4Cp) (cyclohexyl-N)TiCl2, SiMe2 (Me4Cp) (Ph-N)TiCl2, SiPh2 (Me4Cp) ( t Bu-N)TiCl2, SiPh2 (Me4Cp) (iPr-N)TiCl2, SiPh2 (Me4Cp) (adamantane-N) TiCl2, SiPh2 (Me4Cp) (cyclohexyl-N) TiCl2, SiPh2(Me4Cp) (Ph-N) TiCl2, SiMe2 (Me4Cp) ( n Bu-N)TiCl2 and SiPh2 (Me4Cp) n One or more of Bu-N)TiCl2.

[0009] The unbridged metallocene compounds include bis(cyclopentadienyl)zirconia dichloride, bis(cyclopentadienyl)dimethylzirconia, bis(n-butylcyclopentadienyl)zirconia dichloride (nBuCp)2ZrCl2, bis(n-butylcyclopentadienyl)dimethylzirconia, bis(pentamethylcyclopentadienyl)zirconia dichloride, bis(pentamethylcyclopentadienyl)dimethylzirconia, bis(pentamethylcyclopentadienyl)hafnium dichloride, bis(pentamethylcyclopentadienyl)dimethylzirconia, bis(1-methyl-3-n-butylcyclopentadienyl)zirconia dichloride, bis(1-methyl-3-n-butylcyclopentadienyl)dimethylzirconia ... One or more of the following: (1-methyl-3-phenylcyclopentadienyl)zirconium dichloride, bis(1-methyl-3-phenylcyclopentadienyl)dimethylzirconium, bis(1-methyl-3-n-butylcyclopentadienyl)hafnium dichloride, bis(1-methyl-3-n-butylcyclopentadienyl)dimethylzirconium, bis(indenyl)zirconium dichloride, bis(indenyl)dimethylzirconium, bis(tetrahydro-1-indenyl)zirconium dichloride, bis(tetrahydro-1-indenyl)dimethylzirconium, (n-propylcyclopentadienyl)(pentamethylcyclopentadienyl)zirconium dichloride, and (n-propylcyclopentadienyl)(pentamethylcyclopentadienyl)dimethylzirconium.

[0010] The molar ratio of the bridged metallocene compound to the unbridged metallocene compound is 1:(0.7-50); for example, the molar ratio of the bridged metallocene compound to the unbridged metallocene compound is 1:0.7, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, etc. The total content of the bridged metallocene compound and the unbridged metallocene compound is 0.4%-8% of the carrier mass. For example, the total content of the bridged metallocene compound and the unbridged metallocene compound is 0.4%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% of the carrier mass, etc. The carrier material includes one or more of silicon dioxide, aluminum oxide, and silicon dioxide-alumina. And / or, the specific surface area of ​​the carrier is 10-700 m². 2 / g, with an average particle size of 10-500 μm, a pore volume of 0.8-3.0 mL / g, and a pore size of 60-400 Å. For example, the specific surface area of ​​the support is 10 m² / g. 2 / g、20 m 2 / g、30 m 2 / g、50 m 2 / g、100 m 2 / g、200 m 2 / g、300 m 2 / g、400 m 2 / g、500 m 2 / g、600 m 2 / g、700m 2 / g, with average particle sizes of 10μm, 20μm, 30μm, 50μm, 100μm, 200μm, 300μm, 400μm, 500μm, etc., pore volumes of 0.8 mL / g, 1 mL / g, 1.5 mL / g, 2 mL / g, 2.5 mL / g, 3.0 mL / g, etc., and pore sizes of 60 Å, 80 Å, 100 Å, 200 Å, 300 Å, 400 Å, etc.; The activator comprises aluminum oxane and / or noncoordinate anions. Noncoordinate anions include triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, trimethylammonium tetra(p-tolyl)borate, and trimethylammonium tetra(o-tolyl)borate. Tributylammonium tetra(pentafluorophenyl)borate, Tripropylammonium tetra(o,p-dimethylphenyl)borate Tributylammonium tetra(m, m-dimethylphenyl)borate, Tributylammonium tetra(p-trifluoromethylphenyl)borate, Tributylammonium tetra(pentafluorophenyl)borate, Tri(n-butyl)ammonium tetra(o-tolyl)borate, Methyldi-(octadecyl)ammonium tetra(pentafluorophenyl)borate, N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate, N,N-dimethylphenylammonium tetra(heptafluoronaphthyl)borate, N,N-dimethylphenylammonium tetra(perfluoro-4-biphenyl)borate, N,N-dimethylphenylammonium tetraphenylborate, N,N-diethylphenylammonium tetraphenylborate, N,N-2,4,6-pentamethylphenylammonium tetraphenylborate, Di(isopropyl)ammonium tetra(pentafluorophenyl)borate, and Dicyclohexylammonium tetraphenylborate. One or more of tetra(pentafluorophenyl)borate, tetra(pentafluorophenyl)borate triphenylmethylonium tetra(pentafluorophenyl)borate, tetra(pentafluorophenyl)borate diazobenzene, and phenyltri(pentafluorophenyl)borate.

[0011] And / or, the content of the activator is 50%-150% of the carrier mass, for example: the content of the activator is 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, 150% of the carrier mass, etc.

[0012] The unbridged metallocene compound comprises at least two isomers.

[0013] A method for preparing the above-mentioned supported catalyst system includes: mixing the support and the activator with a solvent, mixing thoroughly, adding a bridged metallocene compound and an unbridged metallocene compound, and then washing and drying to obtain the product.

[0014] This invention also provides the application of the above-described supported catalyst system in olefin monomer polymerization.

[0015] The olefin monomer includes at least ethylene, and further includes at least one of propylene, 1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, and 1-decene. That is, the olefin monomer may be ethylene alone, or it may be a comonomer of ethylene combined with other olefin monomers.

[0016] The polymerization of the present invention is carried out in a slurry or gas phase, and polyolefins are obtained in a continuous manner.

[0017] The polymer produced by this invention has an MFR > 30 and 3 < Mw / Mn < 5. For example, the MFR value is greater than 30, 35, 40, 45, 50, etc.

[0018] The technical solution of this invention has the following advantages: The present invention provides a supported catalyst system that, by simultaneously introducing a bridged metallocene compound with a specific structure as shown in Formula A and an unbridged metallocene compound with a specific structure as shown in Formula B, not only enables the polymerization of olefin monomers to form polymers with high mechanical properties, but also significantly improves the melt strength, toughness, and melt flow ratio of the polymer, thereby significantly enhancing the polymer's processing performance.

[0019] Specifically, the two different catalyst components introduced in this invention have different hydrogen responses (each with different reactivity to hydrogen). Hydrogen is commonly used in olefin polymerization to control the final properties of polyolefins. One catalyst component in this invention exhibits a more negative response to changes in hydrogen concentration in the reactor compared to the other. Due to the different hydrogen responses of the catalyst components in the supported catalyst system of this invention, changes in hydrogen concentration in the reactor can affect the molecular weight, molecular weight distribution, and other properties of the resulting polyolefin when using a combination of these two catalyst components, thus significantly impacting the polymer's processing and mechanical properties. This invention has verified that using the two types of catalyst components with specific structures in this invention in combination can effectively produce unimodal polyethylene with excellent mechanical properties, while simultaneously achieving a synergistic improvement in processing performance, demonstrating a highly significant effect. Detailed Implementation

[0020] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0021] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0022] Example 1 A supported catalyst system, the preparation process of which is as follows: 50g of silica gel (model 955) activated at 600℃ was placed in a 2L reactor, along with 200g of methylaluminoxane (MAO) (a 30wt% MAO toluene solution) and 200g of toluene. The slurry was heated at 50℃ and stirred at 120rpm for 3 hours. The temperature was then lowered to 25℃ and cooled to room temperature over 2 hours. Once cooled, the vessel was set to 8rpm and placed under vacuum for 72 hours. 1.5g of (nBuCp)₂ZrCl₂ and 1.45g of SiMe₂(Me₄Cp)₂ were added. t Bu-N)TiMe2 was added to the slurry and stirred for 2 hours; after conversion, the content of the activator was 120% of the carrier mass, and the bridged metallocene compound SiMe2 (Me4Cp) ( t The molar ratio of Bu-N)TiMe2 to the unbridged metallocene compound (nBuCp)2ZrCl2 is 1:1, and the total content of the bridged and unbridged metallocene compounds is 5.9% of the support mass. The slurry is filtered, the solid is washed with 150 mL of toluene, and dried under vacuum. 105 g of a pale yellow solid is collected; this pale yellow solid is the supported catalyst system 1A of the present invention.

[0023] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of supported catalyst system 1A is then added to the reactor, ethylene is introduced, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 125g of polymer.

[0024] Example 2 A supported catalyst system differs from Example 1 in that the raw material composition is different. Specifically, silica gel (model 955) is replaced with SIRAL 30 (a support composed of silica and alumina), while the rest is the same as in Example 1, to prepare supported catalyst system 2A.

[0025] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of supported catalyst system 2A is then added to the reactor, ethylene is introduced, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 107.5g of polymer.

[0026] Example 3 A supported catalyst system differs from Example 1 in that the raw material composition is different. Specifically, silica gel (model 955) is replaced with SIRAL 70 HPV (a support composed of alumina), while the rest is the same as in Example 1, to prepare supported catalyst system 3A.

[0027] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of supported catalyst system 3A is then added to the reactor, ethylene is introduced, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 96.5g of polymer.

[0028] Example 4 A supported catalyst system differs from Example 1 in that the raw material composition is different. Specifically, methylaluminoxane (MAO) is replaced with tetra(pentafluorophenyl)boronic acid-methyldi-(octadecyl)ammonium salt (an activator composed of non-coordinated anions), while the rest is the same as in Example 1, to prepare supported catalyst system 4A.

[0029] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of supported catalyst system 4A is then added to the reactor, ethylene is introduced, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 120.3g of polymer.

[0030] Example 5 A supported catalyst system differs from Example 1 in that the raw material composition is different. Specifically, (nBuCp)2ZrCl2 is replaced with bis(pentamethylcyclopentadienyl)hafnium dichloride, while the rest is the same as in Example 1, to prepare supported catalyst system 5A.

[0031] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of the supported catalyst system 5A is then added to the reactor, ethylene is introduced, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 87.3 g of polymer.

[0032] Example 6 A supported catalyst system differs from Example 1 in that the raw material composition is different. Specifically, (nBuCp)2ZrCl2 is replaced with (n-propylcyclopentadienyl) (pentamethylcyclopentadienyl) dimethylzirconium, while the rest is the same as in Example 1, to prepare supported catalyst system 6A.

[0033] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of the supported catalyst system 6A is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 76.6g of polymer.

[0034] Example 7 A supported catalyst system differs from Example 1 in that the raw material composition is different. Specifically, (nBuCp)2ZrCl2 is replaced with bis(indenyl)dimethylzirconium, while the rest is the same as in Example 1, to prepare supported catalyst system 7A.

[0035] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of the supported catalyst system 7A is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 116.4g of polymer.

[0036] Example 8 A supported catalyst system differs from Example 1 in that the raw material composition is different; specifically, SiMe2(Me4Cp) is used. t The Bu-N)TiMe2 was replaced with SiMe2 (Me4Cp) (adamantane-N)TiCl2, and the rest was the same as in Example 1, to prepare the supported catalyst system 8A.

[0037] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of the supported catalyst system 8A is then added to the reactor, ethylene is introduced, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 136.8g of polymer.

[0038] Example 9 A supported catalyst system differs from Example 1 in that the raw material composition is different; specifically, SiMe2(Me4Cp) is used. t The Bu-N)TiMe2 was replaced with SiPh2(Me4Cp)(iPr-N)TiCl2, and the rest was the same as in Example 1, to prepare the supported catalyst system 9A.

[0039] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750 mL of hexane and 50 mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10 mg of the supported catalyst system 9A is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2 MPa, and polymerization is maintained at 85°C for 2 hours, yielding 93.6 g of polymer.

[0040] Example 10 A supported catalyst system differs from Example 1 in that the raw material composition is different; specifically, SiMe2(Me4Cp) is used. t The Bu-N)TiMe2 was replaced with SiMe2 (Me4Cp)(Ph-N)TiCl2, and the rest was the same as in Example 1, to prepare the supported catalyst system 10A.

[0041] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of supported catalyst system 10A is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 103.5g of polymer.

[0042] Example 11 A supported catalyst system, the preparation process of which is as follows: 50g of silica gel (model 955) activated at 600℃ was placed in a 2L reactor, along with 250g of methylaluminoxane (MAO) (a 30wt% MAO toluene solution) and 200g of toluene. The slurry was heated at 50℃ and stirred at 120rpm for 3 hours. The temperature was then lowered to 25℃ and cooled to room temperature over 2 hours. Once cooled, the vessel was set to 8rpm and placed under vacuum for 72 hours. 3.92g of (nBuCp)₂ZrCl₂ and 0.08g of SiMe₂(Me₄Cp)₂ were added. t Bu-N)TiMe2 was added to the slurry and stirred for 2 hours; after conversion, the content of the activator was 150% of the carrier mass, and the bridged metallocene compound SiMe2 (Me4Cp) ( t The molar ratio of Bu-N)TiMe2 to the unbridged metallocene compound (nBuCp)2ZrCl2 is 1:48, and the total content of the bridged and unbridged metallocene compounds is 8% of the support mass. The slurry is filtered, the solid is washed with 150 mL of toluene, and dried under vacuum. 126 g of a pale yellow solid is collected; this pale yellow solid is the supported catalyst system 11A of the present invention.

[0043] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of supported catalyst system 11A is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 201.7g of polymer.

[0044] Example 12 A supported catalyst system, the preparation process of which is as follows: 50 g of silica gel (model 955) activated at 600 °C was placed in a 2 L reactor, along with 83.3 g of methylaluminoxane (MAO) (a 30 wt% MAO toluene solution) and 200 g of toluene. The slurry was heated at 50 °C and stirred at 120 rpm for 3 hours. The temperature was then lowered to 25 °C and cooled to room temperature over 2 hours. Once cooled, the vessel was set to 8 rpm and placed under vacuum for 72 hours. 0.102 g of (nBuCp)₂ZrCl₂ and 0.098 g of SiMe₂(Me₄Cp)₂ were then added. t Bu-N)TiMe2 was added to the slurry and stirred for 2 hours; after conversion, the content of the activator was 50% of the carrier mass, and the bridged metallocene compound SiMe2 (Me4Cp) ( tThe molar ratio of Bu-N)TiMe2 to the unbridged metallocene compound (nBuCp)2ZrCl2 is 1:1, and the total content of the bridged and unbridged metallocene compounds is 0.4% of the support mass. The slurry is filtered, the solid is washed with 150 mL of toluene, and dried under vacuum. 83.7 g of a pale yellow solid is collected; this pale yellow solid is the supported catalyst system 12A of the present invention.

[0045] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750 mL of hexane and 50 mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10 mg of supported catalyst system 12A is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2 MPa, and polymerization is maintained at 85°C for 2 hours, yielding 77.4 g of polymer.

[0046] Example 13 A supported catalyst system, the preparation process of which is as follows: 50g of silica gel (model 955) activated at 600℃ was placed in a 2L reactor, along with 150g of methylaluminoxane (MAO) (a 30wt% MAO toluene solution) and 200g of toluene. The slurry was heated at 50℃ and stirred at 120rpm for 3 hours. The temperature was then lowered to 25℃ and cooled to room temperature over 2 hours. Once cooled, the vessel was set to 8rpm and placed under vacuum for 72 hours. 1.4g of (nBuCp)₂ZrCl₂ and 0.6g of SiMe₂(Me₄Cp)₂ were added. t Bu-N)TiMe2 was added to the slurry and stirred for 2 hours; after conversion, the content of the activator was 90% of the carrier mass, and the bridged metallocene compound SiMe2 (Me4Cp) ( t The molar ratio of Bu-N)TiMe2 to the unbridged metallocene compound (nBuCp)2ZrCl2 is 1:2.3, and the total content of the bridged and unbridged metallocene compounds is 4% of the support mass. The slurry is filtered, the solid is washed with 150 mL of toluene, and dried under vacuum. 105 g of a pale yellow solid is collected; this pale yellow solid is the supported catalyst system 13A of the present invention.

[0047] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of supported catalyst system 13A is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 64.2g of polymer.

[0048] Example 14 A supported catalyst system, the preparation process of which is as follows: 50g of silica gel (model 955) activated at 600℃ was placed in a 2L reactor, along with 150g of methylaluminoxane (MAO) (30wt% toluene solution) and 200g of toluene. The slurry was heated at 50℃ and stirred at 120rpm for 3 hours. The temperature was then lowered to 25℃ and cooled to room temperature over 2 hours. Once cooled, the vessel was set to 8rpm and placed under vacuum for 72 hours. 1.5g of (nBuCp)₂ZrCl₂, 0.7g of (n-propylcyclopentadienyl)(pentamethylcyclopentadienyl)dimethylzirconium, and 0.9g of SiMe₂(Me₄Cp) were added. t Bu-N)TiMe2 was added to the slurry and stirred for 2 hours; after conversion, the content of the activator was 90% of the carrier mass, and the bridged metallocene compound SiMe2 (Me4Cp) ( t The molar ratio of Bu-N)TiMe2 to the unbridged metallocene compound (n-propylcyclopentadienyl) (pentamethylcyclopentadienyl) dimethylzirconium and (nBuCp)2ZrCl2 is 1:2.4, and the total content of the bridged metallocene compound and the unbridged metallocene compound is 6.2% of the carrier mass. The slurry is filtered, the solid is washed with 150 mL of toluene, and dried under vacuum. 105 g of the pale yellow solid is collected, which is the supported catalyst system 14A of the present invention.

[0049] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750 mL of hexane and 50 mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10 mg of supported catalyst system 14A is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2 MPa, and polymerization is maintained at 85°C for 2 hours, yielding 142.2 g of polymer.

[0050] Comparative Example 1 A supported catalyst system, wherein catalyst MTE-1 replaces (nBuCp)2ZrCl2 and MTE-3 replaces SiMe2(Me4Cp) in the examples of CN103848931A. t The supported catalyst system B was prepared by Bu-N)TiMe2.

[0051] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of the supported catalyst system B is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 11.4g of polymer.

[0052] Comparative Example 2 A supported catalyst system, the preparation process of which is as follows: 50 g of silica gel (model 955) activated at 600 °C was placed in a 2 L reactor, along with 200 g of methylaluminoxane (MAO) (a 30 wt% MAO toluene solution) and 200 g of toluene. The slurry was heated at 50 °C and stirred at 120 rpm for 3 hours. The temperature was then lowered to 25 °C and cooled to room temperature over 2 hours. Once cooled, the vessel was set to 8 rpm and placed under vacuum for 72 hours. 2.95 g of (nBuCp)₂ZrCl₂ was added to the slurry and stirred for 2 hours. The slurry was filtered, the solid was washed with 150 mL of toluene, and dried under vacuum. 105 g of a pale yellow solid was collected; this pale yellow solid is the supported catalyst system C of this invention.

[0053] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of the supported catalyst system C is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 53g of polymer.

[0054] Comparative Example 3 A supported catalyst system, the preparation process of which is as follows: 50g of silica gel (model 955) activated at 600℃ was placed in a 2L reactor, along with 200g of methylaluminoxane (MAO) (a 30wt% MAO toluene solution) and 200g of toluene. The slurry was heated at 50℃ and stirred at 120rpm for 3 hours. The temperature was then lowered to 25℃ and cooled to room temperature over 2 hours. Once cooled, the vessel was set to 8rpm and placed under vacuum for 72 hours. 2.95g of SiMe2 (Me4Cp) was then added. t Bu-N)TiMe2 was added to the slurry and stirred for 2 hours. The slurry was filtered, the solid was washed with 150 mL of toluene, and dried under vacuum. 104 g of a pale yellow solid was collected, which is the supported catalyst system D of the present invention.

[0055] The application of the above-mentioned supported catalyst system in olefin polymerization involves the following steps: A 2L stainless steel polymerization reactor is dried at 120°C for 4 hours and purged with nitrogen multiple times. 750mL of hexane and 50mL of 1-hexene are added to the reactor, and the mixture is heated to 85°C. 10mg of the supported catalyst system D is then added to the reactor. Ethylene is introduced into the reactor, the pressure is adjusted to 2MPa, and polymerization is maintained at 85°C for 2 hours, yielding 27g of polymer.

[0056] Experimental Example The polymers prepared using the various examples and comparative examples were tested, and the specific test results are as follows: (1) Detection of Mw, Mw / Mn and hexene wt% content: obtained by PL-GPC220 at 150 °C, using three PLgel 10 μm MIXED-B separation columns in series, with 1,2,4,-trichlorobenzene as solvent.

[0057] (2) Activity detection: Activity = polymer mass / catalyst mass.

[0058] (4) MFR (Melting Flow Rate) test: 190℃, 2.16kg MI 2.16 190℃, 21.6kg MI 21.6 MFR=MI 21.6 / MI 2.16 .

[0059] (5) Tm / ℃ detection: ISO11357-1:2023 Differential scanning calorimetry (DSC) method.

[0060] (6) Melt strength (cN) test: Rheological ISO16790 method.

[0061] (7) Tensile strength (MPa) and elongation at break (%) were tested using ASTM D882 test method.

[0062] The test results are shown in Table 1 below.

[0063] Table 1

[0064] The carriers in Examples 1-3 above all have a specific surface area of ​​10-700 m². 2 Within the parameter range of / g, average particle size of 10-500μm, pore volume of 0.8-3.0mL / g, and pore size of 60-400Å.

[0065] The data comparison of the above embodiments and comparative examples shows that the supported catalyst system of the present invention has the effect of making the polymer formed by polymerization have higher mechanical properties, and can also significantly improve the melt strength, toughness and melt flow ratio of the polymer, thereby significantly improving the processing performance of the polymer.

[0066] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A supported catalyst system, characterized in that, By mass fraction, the raw materials include bridged metallocene compounds, unbridged metallocene compounds, carriers, and activators. The structure of the bridged metallocene compound is shown in Formula A. Formula A: , M1 is a Group 4 metal. R1-R4 are each independently a hydrogen, alkoxy, or C1-C40 substituted or unsubstituted hydrocarbon group. R5 and R6 are each independently hydrogen, alkoxy, C1-C40 substituted or unsubstituted hydrocarbon group, -R20-SiR'3 or -R20-CR'3, wherein R20 is hydrogen or a C1-C4 hydrocarbon group, and R' is each independently a C1-C20 substituted or unsubstituted hydrocarbon group, and at least one of the R' is not H. R7 is a C1-C40 substituted or unsubstituted hydrocarbon group, alkoxy group, or halogen. R8 represents oxygen, nitrogen, phosphorus, and sulfur. T is a bridging group, C or Si. X are each anionic ligands that are independently monovalent; The structure of the unbridged metallocene compound is shown in Formula B. Formula B: , M2 is a Group 4 metal. R9-R18 are each independently a hydrogen, alkoxy, or C1-C40 substituted or unsubstituted hydrocarbon group. Y is an independent monovalent anion ligand.

2. The supported catalyst system according to claim 1, characterized in that, R5 and R6 are each independently hydrogen, alkoxy, C1-C20 substituted or unsubstituted hydrocarbon group, -R20-SiR'3 or -R20-CR'3; And / or, R9-R18 are each independently hydrogen, alkoxy, or C1-C20 substituted or unsubstituted hydrocarbon groups; And / or, the monovalent anionic ligand is selected from chlorine, bromine, methyl, ethyl and fluorine.

3. The supported catalyst system according to claim 1, characterized in that, The bridging metallocene compounds include SiMe2 (Me4Cp) ( t Bu-N)TiMe2,SiMe2 (Me4Cp) ( t Bu-N)TiCl2, SiMe2 (Me4Cp) (iPr-N)TiCl2, SiMe2 (Me4Cp) (adamantane-N) TiCl2, SiMe2 (Me4Cp) (cyclohexyl-N) TiCl2, SiMe2(Me4Cp) (Ph-N) TiCl2, SiPh2 (Me4Cp) t Bu-N)TiCl2, SiPh2 (Me4Cp) (iPr-N) TiCl2, SiPh2 (Me4Cp) (adamantane-N) TiCl2, SiPh2 (Me4Cp) (cyclohexyl-N) TiCl2, SiPh2 (Me4Cp)(Ph-N) TiCl2, SiMe2 (Me4Cp) ( n Bu-N)TiCl2 and SiPh2 (Me4Cp) n One or more of Bu-N)TiCl2.

4. The supported catalyst system according to claim 1, characterized in that, The unbridged metallocene compounds include bis(cyclopentadienyl)zirconia dichloride, bis(cyclopentadienyl)dimethylzirconia, bis(n-butylcyclopentadienyl)zirconia dichloride, bis(n-butylcyclopentadienyl)dimethylzirconia, bis(pentamethylcyclopentadienyl)zirconia dichloride, bis(pentamethylcyclopentadienyl)dimethylzirconia, bis(pentamethylcyclopentadienyl)hafnium dichloride, bis(pentamethylcyclopentadienyl)dimethylzirconia, bis(1-methyl-3-n-butylcyclopentadienyl)zirconia dichloride, bis(1-methyl-3-n-butylcyclopentadienyl)dimethylzirconia, bis(1-methyl-3-n-butylcyclopentadienyl)dimethylzirconia, bis(1-methyl-3-n- One or more of the following: phenylcyclopentadienyl)zirconia dichloride, bis(1-methyl-3-phenylcyclopentadienyl)dimethylzirconia, bis(1-methyl-3-n-butylcyclopentadienyl)hafnium dichloride, bis(1-methyl-3-n-butylcyclopentadienyl)dimethylzirconia, bis(indenyl)zirconia dichloride, bis(indenyl)dimethylzirconia, bis(tetrahydro-1-indenyl)zirconia dichloride, bis(tetrahydro-1-indenyl)dimethylzirconia, (n-propylcyclopentadienyl)(pentamethylcyclopentadienyl)zirconia dichloride, and (n-propylcyclopentadienyl)(pentamethylcyclopentadienyl)dimethylzirconia.

5. The supported catalyst system according to any one of claims 1-4, characterized in that, The molar ratio of the bridged metallocene compound to the unbridged metallocene compound is 1:(0.7-50). The total content of the bridged metallocene compound and the unbridged metallocene compound is 0.4%-8% of the carrier mass.

6. The supported catalyst system according to any one of claims 1-5, characterized in that, The carrier material includes one or more of silicon dioxide, aluminum oxide, and silicon dioxide-alumina. And / or, the specific surface area of ​​the carrier is 10-700 m². 2 / g, with an average particle size of 10-500μm, pore volume of 0.8-3.0mL / g, and pore size of 60-400Å; And / or, the activator includes aluminoxane and / or noncoordinate anions; And / or, the content of the activator is 50%-150% of the carrier mass.

7. The supported catalyst system according to any one of claims 1-6, characterized in that, The unbridged metallocene compound comprises at least two isomers.

8. A method for preparing the supported catalyst system according to any one of claims 1-7, characterized in that, include: The carrier and the activator are mixed with a solvent, and after mixing, a bridged metallocene compound and an unbridged metallocene compound are added and mixed. After washing and drying, the product is obtained.

9. The application of the supported catalyst system according to any one of claims 1-7 in the polymerization of olefin monomers.

10. The application according to claim 9, characterized in that, The olefin monomer includes at least ethylene, and further includes at least one of propylene, 1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, and 1-decene.

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