A supported metallocene catalyst, its preparation method and application

Abstract

This invention belongs to the field of olefin polymerization technology and discloses a supported metallocene catalyst, its preparation method, and its application. The catalyst comprises a support and a metallocene compound and an alkylaluminoxane supported on the support. The support is a spherical pyrophyllite-clay composite material with three-dimensional cubic channels, made of mesoporous clay silica, silica gel, and pyrophyllite clay minerals. The metallocene compound has the structure shown in Formula 1, where R1, R2, R3, R4, R5, R1', R2', R3', R4', and R5' are each independently hydrogen or a C1-C5 alkyl group, and at least one of R1, R2, R3, R4, and R5 is a C1-C5 alkyl group, at least one of R1', R2', R3', R4', and R5' is a C1-C5 alkyl group, M is one of titanium, zirconium, and hafnium, and X is a halogen. The catalyst of this invention has a stable structure and high catalytic activity.

Description

Technical Field

[0001] This invention belongs to the field of olefin polymerization technology, specifically relating to a supported metallocene catalyst, its preparation method, and its application. Background Technology

[0002] The development and application of metallocene catalysts represents another major breakthrough in the field of olefin polymerization catalysts, following the traditional Ziegler-Natta catalyst. In particular, the development of the highly efficient co-catalyst methylaluminoxane (MAO) by Kaminsky and Sinn et al. in the 1980s propelled the research of metallocene catalysts into a phase of rapid development. However, homogeneous metallocene catalysts require large amounts of MAO to achieve high activity, resulting in high production costs and the absence of particulate polymers, making them unsuitable for widely used slurry or gas-phase polymerization processes. An effective solution to these problems is to support soluble metallocene catalysts. Currently, there are numerous reports on metallocene support studies, with the most extensive research using SiO2, such as 955 silica gel, as a support. For example, patent documents CN1095474C, CN1049439C, CN1157419C, US4808561, US5026797, US5763543, and US5661098 all disclose supported metallocene catalysts using SiO2 as a support. To conduct in-depth research on new support / catalyst / co-catalyst systems, it is necessary to try different supports in order to promote the further development of supported catalysts and the polyolefin industry.

[0003] Supporting olefin polymerization catalysts on molecular sieves has the following advantages:

[0004] (1) Artificially synthesized molecular sieves do not contain impurities that can easily degrade polymers, which will improve the anti-aging properties of polyolefin materials;

[0005] (2) Molecular sieve nanopores have the dual functions of carrier and reactor, with high catalyst loading efficiency, easy control of polymerization process, and can introduce active centers into the framework of polymerization reactor to accelerate reaction process and improve yield.

[0006] (3) It has a stereoselective effect on monomer insertion and polymerization reactions, which can increase the molecular weight and melting point of polyolefins.

[0007] Therefore, the emergence of molecular sieve-supported olefin polymerization catalysts has opened up a new field for olefin coordination polymerization.

[0008] Current literature reports the use of MAO-treated MCM-41 mesoporous materials to support metallocene catalysts for olefin polymerization, but the activity for ethylene polymerization is only 10. 6g PE / (mol Zr h) (Chen ST, Guo CY, Lei L, et al. Polymer, 2005, 46: 11093).

[0009] Patent document CN1923862 discloses a mesoporous molecular sieve-supported olefin polymerization catalyst, which is obtained by supporting a semi-sandwich metallocene compound of the following formula on MAO-treated SBA-15.

[0010]

[0011] However, the catalyst disclosed in patent document CN1923862 has a maximum catalytic activity of only 10. 6 g PE / (mol Zrh).

[0012] Therefore, how to obtain supported metallocene catalysts with high catalytic activity remains a technical problem that urgently needs to be solved. Summary of the Invention

[0013] To address the aforementioned problems in the existing technology, the purpose of this invention is to provide a supported metallocene catalyst, its preparation method, and its application. The resulting catalyst has a stable structure and high activity when used for olefin polymerization.

[0014] The inventors of this invention discovered that the low activity of the mesoporous material MCM-41 in ethylene polymerization after loading with metallocene is mainly due to the poor thermal and hydrothermal stability of the pore wall structure of MCM-41. During the loading process, some pore walls collapse, affecting the loading effect and consequently the catalytic activity. Therefore, this invention seeks a support with a stable mesoporous structure that can maintain an ordered mesoporous structure after loading.

[0015] The geometric shape of spherical mesoporous materials has obvious advantages in reducing powder agglomeration and improving their flowability. Therefore, making mesoporous materials into spherical shapes can not only retain the characteristics of high specific surface area, large pore volume, large pore size and narrow distribution of mesoporous materials, but also reduce the agglomeration of mesoporous materials and increase their flowability.

[0016] Pyrophyllite is a layered clay mineral, a hydrous aluminosilicate pyrophyllite. Due to its inexpensive and readily available nature, good insulation properties, acid resistance, and low hardness, it is a highly promising functional clay mineral.

[0017] Based on the above findings, the inventors of this invention combined pyrophyllite with mesoporous materials to obtain the supported metallocene catalyst carrier of this invention, which has a stable mesoporous structure and a well-dispersed, complete spherical microstructure.

[0018] A first aspect of the present invention provides a supported metallocene catalyst comprising a support and a metallocene compound and an alkylaluminoxane supported on the support; the support is a spherical pyrophyllite-clay composite material with three-dimensional cubic channels made of mesoporous clay silica, silica gel, and pyrophyllite clay minerals; the metallocene compound has the structure shown in Formula 1.

[0019]

[0020] In Formula 1, R1, R2, R3, R4, R5, R1', R2', R3', R4' and R5' are each independently hydrogen or C1-C5 alkyl, and at least one of R1, R2, R3, R4 and R5 is a C1-C5 alkyl, at least one of R1', R2', R3', R4' and R5' is a C1-C5 alkyl, M is one of titanium, zirconium and hafnium, and X is a halogen.

[0021] A second aspect of the present invention provides a method for preparing the above-described supported metallocene catalyst, the method comprising the following steps:

[0022] (1) Under the protection of an inert gas, the support is contacted with an alkylaluminoxane in a solvent, and then the solvent is removed to obtain a support loaded with an alkylaluminoxane.

[0023] (2) Under the protection of an inert gas, the support for the alkylaluminoxane is contacted with the metallocene compound in a solvent, and the solvent is removed to obtain the supported metallocene catalyst.

[0024] A third aspect of the present invention provides the application of the above-described supported metallocene catalyst in olefin polymerization.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The supported metallocene catalyst of this invention has a stable mesoporous structure and a well-dispersed, complete spherical microstructure. The resulting supported metallocene catalyst has a stable structure and exhibits high catalytic activity when used for olefin polymerization.

[0027] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0028] Figure 1 This is a scanning electron microscope image of the carrier prepared in Example 1.

[0029] Figure 2 The X-ray diffraction pattern of the carrier prepared in Example 1 is shown. Detailed Implementation

[0030] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0031] According to a first aspect of the present invention, a supported metallocene catalyst is provided, the catalyst comprising a support and a metallocene compound and an alkylaluminoxane supported on the support; the support is a spherical pyrophyllite-clay composite material with three-dimensional cubic channels made of mesoporous clay silica, silica gel and pyrophyllite clay minerals; the metallocene compound has the structure shown in Formula 1.

[0032]

[0033] In Formula 1, R1, R2, R3, R4, R5, R1', R2', R3', R4' and R5' are each independently hydrogen or C1-C5 alkyl, and at least one of R1, R2, R3, R4 and R5 is a C1-C5 alkyl, at least one of R1', R2', R3', R4' and R5' is a C1-C5 alkyl, M is one of titanium, zirconium and hafnium, and X is a halogen.

[0034] According to the present invention, in Formula 1, the cyclopentadienyl group is capable of forming an n-type reaction with the central metal. 5 A derivative of a cyclopentadiene anion with alkyl substituents. The C1-C5 alkyl group can be one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, and neopentyl.

[0035] Specific examples of cyclopentadienyl groups include: methylcyclopentadienyl, 1,2-dimethyl-cyclopentadienyl, 1,3-dimethyl-cyclopentadienyl, 1,2,3-trimethyl-cyclopentadienyl, 1,2,4-trimethyl-cyclopentadienyl, 1,2,3,4-tetramethyl-cyclopentadienyl, pentamethyl-cyclopentadienyl, ethyl-cyclopentadienyl, 1,2-diethyl-cyclopentadienyl, 1,3-diethyl-cyclopentadienyl, 1,2,4-triethyl- Cyclopentadienyl, 1,3,5-triethyl-cyclopentadienyl, 1-methyl-2-ethyl-cyclopentadienyl, 1-methyl-3-ethyl-cyclopentadienyl, n-propylcyclopentadienyl, isopropylcyclopentadienyl, 1,3-di-n-propyl-cyclopentadienyl, 1-methyl-3-n-propyl-cyclopentadienyl, 1,3-diisopropyl-cyclopentadienyl, 1-methyl-3-isopropyl-cyclopentadienyl, n-butylcyclopentadienyl, sec-butylcyclopentadienyl Isobutylcyclopentadienyl, tert-butylcyclopentadienyl, 1,3-di-n-butyl-cyclopentadienyl, 1-methyl-3-n-butyl-cyclopentadienyl, 1,3-di-sec-butyl-cyclopentadienyl, 1-methyl-3-sec-butyl-cyclopentadienyl, 1,3-diisobutyl-cyclopentadienyl, 1-methyl-3-isobutyl-cyclopentadienyl, 1,3-di-tert-butyl-cyclopentadienyl, 1-methyl-3-tert-butyl-cyclopentadienyl, n-pentylcyclopentadienyl, iso Pentylcyclopentadienyl, tert-pentylcyclopentadienyl, neopentylcyclopentadienyl, 1,3-di-n-pentyl-cyclopentadienyl, 1-methyl-3-n-pentyl-cyclopentadienyl, 1,3-diisopentyl-cyclopentadienyl, 1-methyl-3-isopentyl-cyclopentadienyl, 1,3-di-tert-pentyl-cyclopentadienyl, 1-methyl-3-tert-pentyl-cyclopentadienyl, 1,3-di-neoplyl-cyclopentadienyl, 1-methyl-3-neoplyl-cyclopentadienyl.

[0036] In a preferred embodiment, R1 and R1' are each independently a C1-C5 alkyl group, and R2, R3, R4, R5, R2', R3', R4', and R5' are all hydrogen. Specific examples of cyclopentadienyl groups include: methylcyclopentadienyl, ethylcyclopentadienyl, n-propylcyclopentadienyl, isopropylcyclopentadienyl, n-butylcyclopentadienyl, sec-butylcyclopentadienyl, isobutylcyclopentadienyl, tert-butylcyclopentadienyl, n-pentylcyclopentadienyl, isopentylcyclopentadienyl, tert-pentylcyclopentadienyl, and neopentylcyclopentadienyl.

[0037] More preferably, R1 and R1' are each independently n-butyl or tert-butyl; more preferably, R1 and R1' are both n-butyl.

[0038] According to the present invention, M in different metallocene compound molecules can be the same or different. Preferably, M is zirconium.

[0039] According to the present invention, X in Formula 1 can be one of fluorine, chlorine, bromine, and iodine. X in different metallocene compound molecules can be the same or different. Preferably, X in Formula 1 is chlorine or bromine. More preferably, X in Formula 1 is chlorine.

[0040] In a preferred embodiment, the metallocene compound is bis(n-butylcyclopentadienyl)zirconium dichloride.

[0041] In this invention, the alkylaluminoxane can be any of the various alkylaluminoxanes commonly used in the field of metallocene catalysts. Generally, the alkyl group in the alkylaluminoxane is a C1-C5 alkyl group, and the C1-C5 alkyl group can be any of the aforementioned C1-C5 alkyl groups. Preferably, the alkylaluminoxane is a methylaluminoxane.

[0042] According to the present invention, the carrier has an average particle size of 30-60 micrometers, a specific surface area of ​​150-600 square meters / gram, a pore volume of 0.5-1.5 milliliters / gram, and most probable pore sizes of 2-4, 5-15, and 10-40 nanometers.

[0043] The carrier of this invention is made of mesoporous clay silica, silica gel and pyrophyllite clay mineral, and has a three-pore distribution structure. The three-pore distribution structure is provided by mesoporous clay silica and silica gel. By controlling the synthesis and molding methods, a spherical carrier with the above-mentioned pore structure can be obtained. The use of pyrophyllite clay mineral helps to improve the catalyst activity.

[0044] According to one specific embodiment, the method for preparing the carrier includes the following steps:

[0045] 1) In the presence of a template agent, trimethylpentane and ethanol, tetramethoxysilane was contacted with an acid agent, and the product obtained after contact was crystallized and filtered to obtain mesoporous clay silica filter cake No. 1; hexadecyltrimethylammonium bromide, tetraethyl orthosilicate and ammonia were contacted, and the product obtained after contact was filtered to obtain mesoporous clay silica filter cake No. 2.

[0046] 2) Contact water glass with inorganic acid, and filter the product obtained after contact to obtain silica gel filter cake;

[0047] 3) Mix and ball-mill the No. 1 mesoporous clay silica filter cake, No. 2 mesoporous clay silica filter cake, silica gel filter cake and pyrophyllite clay mineral powder;

[0048] 4) The solid powder obtained after ball milling is slurried with water and then spray-dried. The template agent in the obtained product is then removed to obtain the carrier.

[0049] In step 1) of this invention, there is no particular limitation on the type of template agent, as long as it enables the obtained carrier to have the above-mentioned pore structure. Preferably, the template agent is a triblock copolymer of polyethylene oxide-polypropylene oxide-polyethylene oxide. This template agent can be commercially available (e.g., from Aldrich, trade name P123) or prepared using various existing methods.

[0050] In step 1) of this invention, there is no particular limitation on the type of acid agent; it can be any conventional choice in the art, such as various existing acids or mixtures of acids. The acid or mixture of acids can be used in its pure state or in the form of an aqueous solution, preferably in the form of an aqueous solution. Preferably, the acid agent is a buffer solution of acetic acid and sodium acetate with a pH of 1-6 (preferably 3-5).

[0051] According to the present invention, the molar ratio of the template agent, ethanol, trimethylpentane and tetramethoxysilane can be 1:100-500:200-600:50-200, preferably 1:200-400:250-400:70-150.

[0052] According to the present invention, the molar ratio of ammonia and water in the tetraethyl orthosilicate, hexadecyltrimethylammonium bromide, and ammonia water can be 1:0.1-1:0.1-5:100-200, preferably 1:0.1-0.5:2-4:120-160.

[0053] In this invention, the conditions for contacting the tetramethoxysilane with the acid agent may include: a temperature of 10-60°C, a time of 10-72 hours, and a pH value of 1-7. Preferably, the conditions for contacting the tetramethoxysilane with the acid agent include: a temperature of 10-30°C, a time of 20-40 hours, and a pH value of 3-6. To facilitate more uniform mixing of the substances, the contacting of the tetramethoxysilane with the acid agent is preferably carried out under stirring conditions. The conditions for crystallization may include: a temperature of 30-150°C, and a time of 10-72 hours. Preferably, the conditions for crystallization include: a temperature of 40-80°C, and a time of 20-40 hours.

[0054] In this invention, the contact conditions between hexadecyltrimethylammonium bromide, tetraethyl orthosilicate, and ammonia water may include: a temperature of 25-100°C and a contact time of 1-10 hours. Preferably, the contact temperature is 50-100°C and the contact time is 2-6 hours.

[0055] This invention does not particularly limit the contact method between the template agent, ethanol, acid agent, trimethylpentane, and tetramethoxysilane. For example, the five substances can be mixed and contacted simultaneously, or some of the substances can be mixed and contacted first, and then the remaining substances can be added to the resulting mixture for further mixing. Preferably, the template agent, ethanol, acidic aqueous solution, and trimethylpentane are first stirred and mixed, and then the tetramethoxysilane is added and the mixture is stirred and mixed again.

[0056] According to the present invention, in step 2), the inorganic acid may be one or more of sulfuric acid, nitric acid and hydrochloric acid.

[0057] The conditions for contacting the water glass with the inorganic acid may include: a temperature of 10-60℃, a time of 1-5 hours, and a pH value of 2-4. Preferably, the temperature is 20-40℃ and the time is 1.5-3 hours.

[0058] In step 3) of this invention, based on the total amount of 100 parts by weight of the No. 1 mesoporous clay silica filter cake and the No. 2 mesoporous clay silica filter cake, the amount of the silica gel filter cake is 20-150 parts by weight, and the amount of the pyrophyllite clay mineral powder is 20-150 parts by weight. The weight ratio of the No. 1 mesoporous clay silica filter cake to the No. 2 mesoporous clay silica filter cake can be 0.5-1.5:1.

[0059] In this invention, there are no particular limitations on the specific operation methods and conditions of ball milling, as long as the structure of the carrier is not damaged or substantially not damaged. Those skilled in the art can select various suitable conditions to implement this invention based on the above principles. Specifically, the ball milling is carried out in a ball mill, wherein the diameter of the grinding balls in the ball mill can be 2-3 mm; the number of grinding balls can be reasonably selected according to the size of the grinding jar; for a grinding jar of 50-150 mL, usually one grinding ball can be used; the material of the grinding balls can be agate, polytetrafluoroethylene, etc., preferably agate. The ball milling conditions include: the rotational speed of the grinding balls can be 300-500 r / min, the temperature inside the grinding jar can be 15-100℃, and the ball milling time can be 0.1-100 hours.

[0060] In this invention, the specific operation method and conditions of the spray drying are well known to those skilled in the art. Specifically, a slurry composed of the solid powder and water is added to an atomizer and rotated at high speed to achieve spray drying. The spray drying conditions include: a temperature of 100-300℃ and a rotation speed of 10000-15000 r / min; preferably, the spray drying conditions include: a temperature of 150-250℃ and a rotation speed of 11000-13000 r / min; and most preferably, the spray drying conditions include: a temperature of 200℃ and a rotation speed of 12000 r / min.

[0061] In this invention, the method for removing the template agent can be calcination, and the calcination conditions include: a temperature of 500-700℃, preferably 500-600℃; and a time of 10-40 hours, preferably 20-30 hours, and most preferably 24 hours.

[0062] According to the present invention, the amounts of metallocene compounds and alkylaluminoxanes supported on the support can vary within a wide range. The inventors of the present invention have found that, based on the total weight of the supported metallocene catalyst, when the total amount of the metallocene compounds and alkylaluminoxanes is 10-60% by weight and the content of the support is 40-90% by weight, not only can satisfactory catalytic effects be obtained, but costs can also be reduced. More preferably, based on the total weight of the supported metallocene catalyst, the total amount of the metallocene compounds and alkylaluminoxanes is 45-55% by weight and the content of the support is 45-55% by weight. It should be noted that the content of the metallocene compounds, alkylaluminoxanes, and support in the catalyst is calculated based on the weight of each component's raw material before loading.

[0063] In this invention, the ratio between the alkylaluminoxane and the metallocene compound can be a ratio known to those skilled in the art of olefin polymerization. Specifically, the molar ratio of aluminum in the alkylaluminoxane to M in the metallocene compound can be 10-300:1, preferably 15-250:1, and more preferably 15-200:1.

[0064] According to a second aspect of the present invention, the present invention provides a method for preparing the above-described supported metallocene catalyst, the method comprising the following steps:

[0065] (1) Under the protection of an inert gas, the support is contacted with an alkylaluminoxane in a solvent, and then the solvent is removed to obtain a support loaded with an alkylaluminoxane.

[0066] (2) Under the protection of an inert gas, the support for the alkylaluminoxane is contacted with the metallocene compound in a solvent, and the solvent is removed to obtain the supported metallocene catalyst.

[0067] The present invention does not particularly limit the contact method, and can use various methods known to those skilled in the art, such as dipping or spraying. Dipping allows the solution to penetrate more fully into the pores of the carrier; therefore, dipping is preferred in this invention.

[0068] In this invention, the contact conditions in step (1) include: a contact time of 1-10 hours, preferably 2-6 hours, more preferably 4 hours; and a contact temperature of 25-80°C, preferably 30-60°C, more preferably 50°C.

[0069] According to the present invention, the contact conditions in step (2) include: a contact time of 0.3-2 hours, preferably 0.4-1 hour, more preferably 0.5 hours; and a contact temperature of 25-80°C, preferably 25-50°C, more preferably 30°C.

[0070] In this invention, the amounts of the support, alkylaluminoxane, and metallocene compound can be adjusted and determined based on the content of each component in the catalyst described above.

[0071] According to the present invention, the solvent can be a conventional solvent, such as toluene, and is preferably purified by methods known to those skilled in the art to remove water and the like before use.

[0072] The preparation method of the present invention may further include heating the support at a temperature of 300-900°C for 7-36 hours under an inert gas protection before loading the alkylaluminoxane and the metallocene compound, so as to remove the hydroxyl groups on the surface of the support and the volatile substances (e.g., water) contained in the support.

[0073] According to the present invention, the inert gas can be any gas that does not chemically interact with the support, alkylaluminoxane, or metallocene compound. For example, the inert gas can be nitrogen or argon, preferably nitrogen.

[0074] According to a third aspect of the present invention, the present invention provides the application of the above-described supported metallocene catalyst in olefin polymerization.

[0075] The supported metallocene catalyst of the present invention is a structurally stable catalyst with high catalytic activity. When used in the homopolymerization and copolymerization of ethylene, it exhibits high activity.

[0076] The substances and parameters not specified in this invention can be selected according to existing technology and are conventional techniques in the field. Unless otherwise specified, the operations and processing methods involved in this invention are conventional methods in the field, the instruments used are conventional instruments in the field, and the raw materials used are commercially available.

[0077] The present invention will be further described below with reference to embodiments. However, the invention is not limited to these embodiments.

[0078] In the following examples and comparative examples, the source of the raw materials and the methods for determining the data are as follows:

[0079] Triblock copolymer polyoxyethylene-polyoxypropylene-polyoxyethylene: purchased from Aldrich, P123;

[0080] Methylaluminoxane: purchased from Albemarle, USA, with an average molecular weight (Mn) of 5800;

[0081] Bis(n-butylcyclopentadienyl)zirconium dichloride: purchased from Alfa Aesar, product number H27576;

[0082] Triethylaluminum: TEA, purchased from Zhejiang Furui Chemical Co., Ltd.;

[0083] ES955 silicone: purchased from GRACE.

[0084] 1. X-ray diffraction analysis was performed on an X-ray diffractometer, model D8 Advance, purchased from Bruker AXS, Germany.

[0085] 2. Scanning electron microscopy analysis was performed on a scanning electron microscope, model XL-30, purchased from FEI Corporation, USA.

[0086] 3. Nitrogen adsorption-desorption experimental conditions included: using an Autosorb-1 nitrogen adsorption-desorption apparatus from Quanta Computer (USA), and degassing the sample at 200℃ for 4 hours. All raw materials were chemically pure.

[0087] Example 1

[0088] 1.0 g of triblock copolymer polyoxyethylene-polyoxypropylene-polyoxyethylene and 1.69 g of ethanol were added to 28 mL of a buffer solution of acetic acid and sodium acetate (pH = 4.4). The mixture was stirred at 15 °C until the polyoxyethylene-polyoxypropylene-polyoxyethylene was completely dissolved. Then, 6 g of trimethylpentane was added to the above solution and stirred at 15 °C for 8 hours. Then, 2.13 g of tetramethoxysilane was added to the above solution and stirred at 15 °C for 20 hours. The solution was then transferred to a polytetrafluoroethylene-lined reactor and crystallized in an oven at 60 °C for 24 hours. After filtration and washing with distilled water, No. 1 mesoporous clay silica filter cake was obtained.

[0089] Hexadecyltrimethylammonium bromide and tetraethyl orthosilicate were added to an ammonia solution. The molar ratio of tetraethyl orthosilicate, hexadecyltrimethylammonium bromide, ammonia (25 wt%), and water was 1:0.37:2.8:142. The mixture was stirred at 50 °C until dissolved. The solution was filtered to obtain a mesoporous clay filter cake. The filter cake was washed until the pH reached 7 to obtain mesoporous clay silica filter cake No. 2.

[0090] A 15% by weight water glass solution and a 12% by weight sulfuric acid solution were reacted at a water glass:sulfuric acid weight ratio of 5:1 for 1.5 hours. The pH was adjusted to 3 with 98% by weight sulfuric acid. The reaction mixture was then filtered and washed with distilled water until the sodium ion content was 0.02% by weight, resulting in a silica gel filter cake.

[0091] 10g of the prepared No. 1 mesoporous clay silica filter cake, 10g of No. 2 mesoporous clay silica filter cake, 10g of silica gel filter cake, and 10g of pyrophyllite clay mineral powder were placed together in a 100mL ball mill jar. The ball mill jar was made of polytetrafluoroethylene, and the grinding balls were made of agate with a diameter of 3mm. One grinding ball was used, and the rotation speed was 400r / min. The ball mill jar was sealed and milled at 60℃ for 1 hour to obtain 26g of solid powder. This solid powder was dissolved in 30g of deionized water and spray-dried at 200℃ and 12000r / min. The spray-dried product was calcined in a muffle furnace at 500℃ for 24 hours to remove the template agent, yielding 24g of the target product carrier after template agent removal, named JKGJYL. A scanning electron microscope image of the carrier is shown below. Figure 1 As shown, the X-ray diffraction pattern is as follows: Figure 2 As shown, the structural parameters are listed in Table 1.

[0092] 0.3407 g of activated JKGJYL (heated at 500 °C for 24 hours under nitrogen protection) was transferred to a 250 mL glass reactor that had been fully purged with nitrogen. 20 mL of purified toluene (refluxed with sodium for 24 hours) and 0.4 g of methylaluminoxane were added, and the mixture was stirred at 50 °C for 4 hours. After the reaction was complete, the mixture was allowed to stand, separated into layers, and the liquid was filtered off. The solid was washed three times with 20 mL of hexane, and finally dried with nitrogen to obtain JKGJYL supported on methylaluminoxane (named MAO / JKGJYL).

[0093] Under nitrogen protection, MAO / JKGJYL was added to a 250 mL glass reactor, followed by 20 mL of purified toluene (refluxed with sodium for 24 hours). At 30 °C, 15.6 mg of bis(n-butylcyclopentadienyl)zirconium dichloride was added dropwise, and the reaction was stirred for 0.5 hours. After the reaction was complete, the mixture was allowed to stand, and the layers were separated. The liquid was filtered off, and the solid was washed three times with 10 mL of toluene, followed by two times with 40 mL of hexane. The solid was then dried under nitrogen to obtain the supported metallocene catalyst (named JKGJYL-BU). The structural parameters of the catalyst are shown in Table 1.

[0094] Application Example 1

[0095] In a 2-liter stainless steel high-pressure polymerization reactor, the reactor was purged three times each with nitrogen and ethylene. Then, 200 mL of hexane was added, and the reactor temperature was raised to 80°C. Another 800 mL of hexane was added, followed by 2 mL of a 1 mol / L triethylaluminum hexane solution. Next, 43.3 mg of JKGJYL-BU was added. Ethylene was introduced to raise the pressure to 1.0 MPa and maintain it at 1.0 MPa. The reaction was carried out at 70°C for 1 hour. The catalyst efficiency was calculated to be 2000 g PE / gcat·h.

[0096] Application Example 2

[0097] In a 2-liter stainless steel high-pressure polymerization reactor, the reactor was purged three times each with nitrogen and ethylene. Then, 200 mL of hexane was added, and the reactor temperature was raised to 80°C. Another 800 mL of hexane was added, followed by 2 mL of a 1 mol / L triethylaluminum (TEA) hexane solution and 10 mL of hexene. Next, 40.3 mg of JKGJYL-BU was added. Ethylene was introduced to raise the pressure to 1.0 MPa and maintain it at 1.0 MPa. The reaction was carried out at 70°C for 1 hour. The catalyst efficiency was calculated to be 3000 g PE / gat·h.

[0098] Comparative Example 1

[0099] ES955 silicone was calcined at 400°C for 10 hours under nitrogen protection to remove hydroxyl groups and residual moisture, thereby obtaining thermally activated ES955 silicone.

[0100] Under nitrogen protection, 0.9 g of ES955 silica gel, 1.0 g of methylaluminoxane, and 10 mL of toluene (refluxed with sodium for 24 hours) were stirred and reacted at 50 °C for 4 hours. The solid was washed three times with toluene, then washed three times with 20 mL of hexane, and finally dried with nitrogen to obtain ES955 loaded with methylaluminoxane (named MAO / ES955).

[0101] Under nitrogen protection, MAO / ES955 was added to a 250 mL glass reactor, along with 20 mL of purified toluene (refluxed with sodium for 24 hours). At 30 °C, 49 mg of the metallocene catalyst precursor bis(n-butylcyclopentadienyl)zirconium dichloride was added dropwise, and the reaction was stirred for 0.5 hours. After the reaction was complete, the mixture was allowed to stand, the liquid was filtered off, and the solid was washed three times with 10 mL of toluene, followed by two washes with 40 mL of hexane. The solid was then dried under nitrogen to obtain the supported metallocene catalyst (named ES955-BU).

[0102] Comparative Example 2

[0103] The difference from Example 1 is that the carrier does not contain pyrophyllite clay mineral powder, and pyrophyllite clay mineral powder is not added during ball milling. Otherwise, it is the same as Example 1, and the catalyst obtained is JKGJ-BU.

[0104] Comparative Example 3

[0105] The difference from Example 1 is that the carrier does not contain silica gel and pyrophyllite clay mineral powder, and silica gel and pyrophyllite clay mineral powder are not added during ball milling. Otherwise, it is the same as Example 1, and the catalyst obtained is JK-BU.

[0106] Application Comparative Example 1

[0107] The homopolymerization of ethylene was carried out using the same method as in Application Example 1, except that the catalyst used was ES955-BU prepared in Comparative Example 1. The catalyst efficiency was calculated to be 694 gPE / gcat·h.

[0108] Application Comparative Example 2

[0109] Ethylene and hexene were copolymerized using the same method as in Application Example 2, except that the catalyst used was ES955-BU prepared in Comparative Example 1. The catalyst efficiency was calculated to be 1361 g PE / gcat·h.

[0110] Application Comparative Example 3

[0111] The homopolymerization of ethylene was carried out using the same method as in Application Example 1, except that the catalyst used was JKGJ-BU prepared in Comparative Example 2. The catalyst efficiency was calculated to be 1200 gPE / gcat·h.

[0112] Application Comparative Example 4

[0113] Ethylene and hexene were copolymerized using the same method as in Application Example 2, except that the catalyst used was JKGJ-BU prepared in Comparative Example 2. The catalyst efficiency was calculated to be 1000 g PE / gcat·h.

[0114] Application Comparative Example 5

[0115] The homopolymerization of ethylene was carried out using the same method as in Application Example 1, except that the catalyst used was JK-BU prepared in Comparative Example 3. The catalyst efficiency was calculated to be 1300 gPE / gcat·h.

[0116] Application Comparative Example 6

[0117] Ethylene and hexene were copolymerized using the same method as in Application Example 2, except that the catalyst used was JK-BU prepared in Comparative Example 3. The catalyst efficiency was calculated to be 1100 gPE / gcat·h.

[0118] Table 1

[0119]

[0120] As can be seen from the data in Table 1, the pore structure parameters of JKGJYL-BU are lower than those of JKGJYL, indicating that methylaluminoxane and metallocene compounds have indeed entered the pores of JKGJYL.

[0121] from Figure 1 Scanning electron microscopy images show that JKGJYL has a spherical microstructure. From Figure 2 The XRD pattern clearly shows that JKGJYL exhibits diffraction peaks in the small-angle region.

[0122] Data from the application examples and comparative examples show that the supported metallocene catalyst provided by this invention exhibits activities of 2000 g PE / gcat·h and 3000 g PE / gcat·h for ethylene homopolymerization and copolymerization, respectively. In contrast, the activities of the same active component supported on industrially common 955 silica gel for ethylene homopolymerization and copolymerization are 694 g PE / gcat·h and 1361 g PE / gcat·h, respectively. Therefore, the catalyst of this invention has higher activity.

[0123] Furthermore, the catalyst of the present invention exhibits higher catalytic activity compared to supports using materials without added pyrophyllite clay mineral powder. The catalyst of the present invention also exhibits higher catalytic activity compared to supports using materials without added silica gel and pyrophyllite clay mineral powder.

[0124] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A supported metallocene catalyst, characterized in that, The catalyst comprises a support and a metallocene compound and an alkylaluminoxane supported on the support; the support is a spherical pyrophyllite-clay composite material with three-dimensional cubic channels, made of mesoporous clay silica, silica gel, and pyrophyllite clay minerals; the metallocene compound has the structure shown in Formula 1. In Formula 1, R1, R2, R3, R4, R5, R1', R2', R3', R4', and R5' are each independently hydrogen or C1-C5 alkyl, and at least one of R1, R2, R3, R4, and R5 is a C1-C5 alkyl, at least one of R1', R2', R3', R4', and R5' is a C1-C5 alkyl, M is one of titanium, zirconium, and hafnium, and X is a halogen; The method for preparing the carrier includes the following steps: 1) In the presence of a template agent, trimethylpentane and ethanol, tetramethoxysilane was contacted with an acid agent, and the product obtained after contact was crystallized and filtered to obtain mesoporous clay silica filter cake No. 1; hexadecyltrimethylammonium bromide, tetraethyl orthosilicate and ammonia were contacted, and the product obtained after contact was filtered to obtain mesoporous clay silica filter cake No.

2. 2) Contact water glass with inorganic acid, and filter the product obtained after contact to obtain silica gel filter cake; 3) Mix and ball-mill the No. 1 mesoporous clay silica filter cake, No. 2 mesoporous clay silica filter cake, silica gel filter cake and pyrophyllite clay mineral powder; 4) The solid powder obtained after ball milling is slurried with water and then spray-dried. The template agent in the obtained product is then removed to obtain the carrier. In step 3), based on the total amount of 100 parts by weight of the No. 1 mesoporous clay silica filter cake and the No. 2 mesoporous clay silica filter cake, the amount of the silica gel filter cake is 20-150 parts by weight, and the amount of the pyrophyllite clay mineral powder is 20-150 parts by weight; the weight ratio of the No. 1 mesoporous clay silica filter cake to the No. 2 mesoporous clay silica filter cake is 0.5-1.5:

1.

2. The supported metallocene catalyst according to claim 1, wherein, In Formula 1, R1 and R1' are each independently a C1-C5 alkyl group, R2, R3, R4, R5, R2', R3', R4' and R5' are all hydrogen; M is zirconium; X is chlorine or bromine.

3. The supported metallocene catalyst according to claim 2, wherein, R1 and R1' are each independently n-butyl or tert-butyl.

4. The supported metallocene catalyst according to claim 3, wherein, R1 and R1' are each independently n-butyl.

5. The supported metallocene catalyst according to claim 2, wherein, X represents chlorine.

6. The supported metallocene catalyst according to claim 1, wherein, The alkyl group in the alkylaluminoxane is a C1-C5 alkyl group.

7. The supported metallocene catalyst according to claim 6, wherein, The alkylaluminoxane is methylaluminoxane.

8. The supported metallocene catalyst according to claim 1, wherein, The carrier has an average particle size of 30-60 micrometers, a specific surface area of ​​150-600 square meters / gram, a pore volume of 0.5-1.5 milliliters / gram, and most probable pore sizes of 2-4, 5-15, and 10-40 nanometers.

9. The supported metallocene catalyst according to claim 1, wherein, In step 1), the template agent is a triblock copolymer of polyethylene oxide-polypropylene oxide-polyethylene oxide, and the acid agent is a buffer solution of acetic acid and sodium acetate with a pH of 1-6; the molar ratio of the template agent, ethanol, trimethylpentane and tetramethoxysilane is 1:100-500:200-600:50-200; the molar ratio of tetraethyl orthosilicate, hexadecyltrimethylammonium bromide, ammonia and water in ammonia water is 1:0.1-1:0.1-5:100-200. The conditions for contacting tetramethoxysilane with an acid include: a temperature of 10-60°C, a time of 10-72 hours, and a pH of 1-7; the conditions for crystallization include: a temperature of 30-150°C, and a time of 10-72 hours; the conditions for contacting hexadecyltrimethylammonium bromide, tetraethyl orthosilicate, and ammonia water include: a temperature of 25-100°C, and a time of 1-10 hours.

10. The supported metallocene catalyst according to claim 1, wherein, In step 2), the inorganic acid is one or more of sulfuric acid, nitric acid, and hydrochloric acid; The conditions for contact between the water glass and the inorganic acid include: a temperature of 10-60℃, a time of 1-5 hours, and a pH value of 2-4.

11. The supported metallocene catalyst according to claim 1, wherein, Based on the total weight of the supported metallocene catalyst, the total amount of the metallocene compound and alkylaluminoxane is 10-60% by weight, and the content of the support is 40-90% by weight; the molar ratio of aluminum in the alkylaluminoxane to M in the metallocene compound is 10-300:

1.

12. The supported metallocene catalyst according to claim 11, wherein, Based on the total weight of the supported metallocene catalyst, the total amount of the metallocene compound and alkylaluminoxane is 45-55% by weight, and the content of the support is 45-55% by weight.

13. The supported metallocene catalyst according to claim 11, wherein, The molar ratio of aluminum in the alkylaluminoxane to M in the metallocene compound is 15-250:

1.

14. The supported metallocene catalyst according to claim 13, wherein, The molar ratio of aluminum in the alkylaluminoxane to M in the metallocene compound is 15-200:

1.

15. A method for preparing the supported metallocene catalyst according to any one of claims 1-14, characterized in that, The preparation method includes the following steps: (1) Under the protection of an inert gas, the support is contacted with an alkylaluminoxane in a solvent, and then the solvent is removed to obtain a support loaded with an alkylaluminoxane. (2) Under the protection of an inert gas, the support for the alkylaluminoxane is contacted with the metallocene compound in a solvent, and the solvent is removed to obtain the supported metallocene catalyst.

16. The method for preparing the supported metallocene catalyst according to claim 15, wherein, The contact conditions in step (1) include: contact time of 1-10 hours; contact temperature of 25-80℃; The contact conditions in step (2) include: contact time of 0.3-2 hours; contact temperature of 25-80℃.

17. The method for preparing the supported metallocene catalyst according to claim 16, wherein, The contact conditions in step (1) include: contact time of 2-6 hours; contact temperature of 30-60℃.

18. The method for preparing the supported metallocene catalyst according to claim 16, wherein, The contact conditions in step (2) include: contact time of 0.4-1 hour; contact temperature of 25-50℃.

19. The use of the supported metallocene catalyst according to any one of claims 1-14 in olefin polymerization.

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