Solid catalyst component, process for its preparation and use in olefin polymerization catalysts

Abstract

This invention relates to a solid catalyst component and its preparation method, an olefin polymerization catalyst, and its applications. The solid catalyst component is obtained by reacting magnesium halides, organic epoxy compounds, organophosphorus compounds, organic alcohol compounds, aromatic ester compounds, titanium halides or their derivatives, and organoaluminum compounds. The olefin polymerization catalyst includes a solid catalyst component and a co-catalyst component. The olefin polymerization catalyst obtained by this invention, while maintaining its basic performance, has a narrow particle size distribution, produces polymer particles with regular morphology, and contains very few large particles and fine powders. The catalyst preparation process is simple and highly suitable for ethylene slurry polymerization processes and catalyst combination polymerization processes requiring good particle morphology and concentrated particle size distribution.

Description

Technical Field

[0001] This invention relates to the field of olefin polymerization catalysts, and more specifically, to a solid catalyst component and its preparation method, an olefin polymerization catalyst, and its applications. Background Technology

[0002] After nearly 70 years of development, Ziegler-Natta type polyethylene catalysts have made significant progress in terms of activity, powder bulk density, fine powder content, and oligomer content. These catalysts are mainly used in the production of general-purpose polyethylene resin, basically meeting the current needs of the national economy. However, with the introduction of new process technologies, the performance of existing catalysts is unstable when producing high-end specialty resins, easily causing problems such as resin stickiness, reactor scaling, short safe operating cycles, and poor performance of polymerized products. To better adapt to the demands of new process technologies and produce resin products with superior performance, it is necessary to provide catalyst products with better particle morphology and more concentrated particle size distribution, while ensuring the basic performance of existing catalysts.

[0003] In existing technologies, introducing electron donors into olefin polymerization catalysts can improve catalyst performance. For example, CN112437780A, CN110072896 A, and CN109661411 A improve catalyst performance by introducing bidentate compounds, carboxylic acid esters, and cyclic ethers as electron donors to optimize the catalyst preparation process. CN108690153 A, CN112574339A, and CN107840914A improve catalyst hydrogen sensitivity, copolymerization ability, and polymer packing density by introducing organophosphorus compounds, haloalkanes, diethers, and phthalate esters as electron donors. CN103772554A only uses organoaluminum compounds as reducing agents for the main catalyst or as impurity removal agents for the reaction system, without applying them as components in catalyst preparation.

[0004] The electron donors mentioned above can only improve the performance of olefin polymerization catalysts in certain aspects, and are no longer sufficient to meet the needs of new process technologies. It is necessary to find a type of electron donor that, while ensuring excellent overall catalyst performance, can improve the particle morphology of polyolefin catalysts, reduce the generation of irregularly shaped particles, and achieve a more concentrated polymer particle size distribution, thus meeting the requirements for the production of high-performance, high-value-added resin products. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention proposes a solid catalyst component for olefin polymerization. Specifically, it relates to a solid catalyst component, catalyst, its preparation method, and its applications for olefin polymerization. The inventors have discovered that introducing an organoaluminum compound as a catalyst preparation component during catalyst preparation results in polymers with improved particle morphology, reduced irregular particle formation, narrower catalyst particle size distribution, and more concentrated polymer powder particle size distribution. Based on this discovery, this invention is proposed.

[0006] One objective of this invention is to provide a solid catalyst component obtained by reacting magnesium halide, organic epoxy compound, organic phosphorus compound, organic alcohol compound, aromatic ester compound, titanium halide or its derivative, and a first organoaluminum compound.

[0007] in,

[0008] The magnesium halide is a magnesium dihalide, which may specifically be at least one of magnesium dichloride, magnesium dibromide, and magnesium diiodide, with magnesium dichloride being preferred.

[0009] The organic epoxy compound is selected from at least one of C2-C8 aliphatic olefins, dienes, or oxides of halogenated aliphatic olefins or dienes, glycidyl ethers, internal ethers, etc. Specific compounds may be selected from: ethylene oxide, propylene oxide, epibutylene oxide, epichlorohydrin, methyl glycidyl ether, diglycidyl ether, tetrahydrofuran, etc. Preferably, at least one of ethylene oxide, propylene oxide, epichlorohydrin, and tetrahydrofuran is preferred, and more preferably tetrahydrofuran and / or epichlorohydrin.

[0010] The organophosphorus compound is selected from at least one of the following: alkyl esters of orthophosphoric acid, alkyl esters of phosphorous acid, haloalkyl esters of orthophosphoric acid, and haloalkyl esters of phosphorous acid. Specifically, it can be selected from at least one of the following: trimethyl orthophosphoric acid, triethyl orthophosphoric acid, tributyl orthophosphoric acid, triphenyl phosphite, trimethyl orthophosphoric acid, triethyl orthophosphoric acid, tributyl orthophosphoric acid, triphenyl phosphite, and benzyl phosphite. Among these, at least one of trimethyl orthophosphoric acid, triethyl orthophosphoric acid, and tributyl orthophosphoric acid is preferred, with tributyl orthophosphoric acid being the most preferred.

[0011] The organic alcohol compound is selected from C1 to C2. 10 Straight-chain, branched, or cycloalkyl alcohols, or C6-C6 alcohols. 20 Alcohols containing aryl groups; the organic alcohol compounds are preferably C1-C1. 10Aliphatic alcohols. Specifically, they may include fatty alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, glycerol, hexanol, 2-methylpentanol, 2-ethylbutanol, 2-ethylhexanol, n-heptanol, n-octanol, and decanol; cycloalkanols such as cyclohexanol and methylcyclohexanol; and aromatic alcohols such as benzyl alcohol, methylbenzyl alcohol, α-methylbenzyl alcohol, and α,α-dimethylbenzyl alcohol. At least one of ethanol, butanol, 2-ethylhexanol, and glycerol is preferred. There are no particular limitations on the proportions of the alcohols in the composition.

[0012] The general formula of the aromatic ester compounds is R 1 n R 2 m C6H 6-n-m-x [(CH2) y COOR 3 ] x , where R 1 and R 2 Each is C1 to C 20 alkyl, aryl, alicyclic or alkoxy, R 3 For C1~C 20an alkyl group, an aryl group or an alicyclic group, 0 ≤ n < 5, 0 ≤ m < 5, 0 < x < 5, 0 ≤ y ≤ 9, where n, m, x, and y are all integers and n + m + x < 5; specifically, the aromatic ester compounds may be selected from: methyl benzoate, ethyl benzoate, propyl benzoate, isopropyl benzoate, butyl benzoate, tert-butyl benzoate, hexyl benzoate, octyl benzoate, cyclohexyl benzoate, 2-methylcyclohexyl benzoate, ethyl o-methylbenzoate, ethyl p-methylbenzoate, ethyl 2,4-dimethylbenzoate, ethyl 2,6-dimethylbenzoate, ethyl 3,5-dimethylbenzoate, ethyl 2,4,6-triisopropylbenzoate, methoxyethyl benzoate, methoxypropyl benzoate, methoxybutyl benzoate, methoxyhexyl benzoate, methoxyoctyl benzoate, ethoxyethyl benzoate, ethoxypropyl benzoate, ethoxybutyl benzoate, ethoxyhexyl benzoate, ethoxyoctyl benzoate, butoxyethyl benzoate, butoxybutyl benzoate, butoxyhexyl benzoate, ethyl 5-acetyl-2-ethoxybenzoate, ethyl 3,4,5-trimethoxybenzoate, methyl phenylacetate, ethyl phenylacetate, propyl phenylacetate, isopropyl phenylacetate, butyl phenylacetate, tert-butyl phenylacetate, hexyl phenylacetate, octyl phenylacetate, cyclohexyl phenylacetate, 2-methylcyclohexyl phenylacetate, ethyl o-methylphenylacetate, ethyl p-methylphenylacetate, ethyl 2,4-dimethylphenylacetate, ethyl 2,6-dimethylphenylacetate, ethyl 3,5-dimethylphenylacetate, ethyl 2,4,6-triisopropylphenylacetate, methoxymethyl phenylacetate, methoxypropyl phenylacetate, methoxybutyl phenylacetate, methoxyhexyl phenylacetate, methoxyoctyl phenylacetate, ethoxyethyl phenylacetate, ethoxypropyl phenylacetate, ethoxybutyl phenylacetate, ethoxyhexyl phenylacetate, ethoxyoctyl phenylacetate, butoxyethyl phenylacetate, butoxybutyl phenylacetate, butoxyhexyl phenylacetate, ethyl (5-acetyl-2-ethoxyphenyl)acetate, ethyl 3,4,5-trimethoxyphenylacetate, methyl phenylpropionate, ethyl phenylpropionate, etc. At least one of them is preferred. At least one of ethyl benzoate, propyl benzoate, ethoxyethyl benzoate, ethyl phenylacetate, and propyl phenylacetate is preferred.

[0013] The general formula of the halide or its derivative of titanium is Ti(OR) a X b , where R is C1 - C 14The hydrocarbon group is preferably a C1-C8 alkyl group; X is a halogen atom, a and b are each independent integers from 0 to 4, and a+b=3 or 4. Specifically, it can be selected from: TiCl3, TiCl4, TiBr4, TiCl4, Ti(OC2H5)Cl3, Ti(OCH3)Cl3, Ti(OC4H9)Cl3, Ti(OC2H5)Br3, Ti(OC2H5)2Cl2, Ti(OCH3)2Cl2, Ti(OCH3)2I2, Ti(OC2H5)3Cl, Ti(OCH3)3Cl, Ti(OC2H5)3I, Ti(OC2H5)4, Ti(OC3H7)4, Ti(OC4H9)4, etc. The preferred inoculants are TiCl3, TiCl4, TiBr4, Ti(OC2H5)2Cl2, Ti(OC2H5)Cl3, Ti(OC2H5)3Cl, Ti(OCH3)Cl3, Ti(OC4H9)Cl3, and Ti(OC4H9)4. TiCl4 is the best.

[0014] The general formula of the first organoaluminum compound is (AlR 4 e X 1 f H g )p, where R 4 It is hydrogen or C l ~C 20 hydrocarbon group, X 1 The atom is a halogen, preferably fluorine, chlorine, or bromine, where e, f, and g are each independent integers from 0 to 3, and e + f + g = 3, and p is 1 or 2; preferably AlEt3, Al(iso-Bu)3, or Al(n-C6H 13 3. Al(n-C8H) 17 3. AlEt2Cl, AlEtCl2, AlMe2Cl, ethyl sesquichloride, etc.

[0015] Based on each mole of magnesium halide, the organic epoxy compound is 0.2 to 10 moles, the organic phosphorus compound is 0.1 to 10 moles, the organic alcohol compound is 0.1 to 6 moles, the aromatic ester compound is 0.1 to 1 mole, the titanium halide or its derivatives are 1 to 20 moles, and the first organoaluminum compound is 0.1 to 6 moles.

[0016] A second objective of this invention is to provide a method for preparing the aforementioned solid catalyst component, comprising the following steps:

[0017] Magnesium halide is reacted with organic epoxy compounds, organic phosphorus compounds, and organic alcohol compounds to form a homogeneous reaction solution; then it is mixed with aromatic ester compounds, titanium halides or their derivatives, and a first organoaluminum compound to obtain the solid catalyst component.

[0018] According to a preferred embodiment of the present invention, the method for preparing the solid catalyst component may include the following steps:

[0019] Magnesium halide is dissolved in an organic epoxy compound and an organophosphorus compound under stirring to form a homogeneous and transparent solution at a mixing temperature of 50–90°C. An organic alcohol compound is added during or after the solution is formed, and the reaction is allowed to proceed for a certain period of time (specifically 1.5–4 hours) to obtain a reaction solution. The reaction solution is then mixed with an aromatic ester compound, a titanium halide or its derivative at -30–0°C. The mixture is slowly heated to 50–120°C, causing solids to precipitate and form particles. The mixture is filtered to remove the mother liquor, and the solids are washed with an inert solvent. A first organoaluminum compound is added at 10–70°C for optimization treatment. After the reaction is complete, the mixture is dried with high-purity nitrogen to obtain a solid catalyst component with good flowability.

[0020] Regarding the preparation of magnesium halide solution: magnesium halide solution is a homogeneous solution obtained by dissolving magnesium halide in a solvent system composed of organic epoxy compound and organic phosphorus compound. During or after the formation of solution, an organic alcohol compound is added, and the reaction is carried out for a certain period of time to obtain a reaction solution. The solvent system referred to here includes those with or without inert diluent.

[0021] The magnesium halide particles used should be of a particle size suitable for dissolution under stirring. Inert diluents such as benzene, toluene, xylene, 1,2-dichloroethane, chlorobenzene, and other hydrocarbons or halogenated hydrocarbons may or may not be added during dissolution. Benzene, toluene, and xylene are preferred, with toluene and xylene being more preferred.

[0022] The feeding ratio of the magnesium halide, organic epoxy compound, organophosphorus compound, organic alcohol compound, aromatic ester compound, transition metal titanium halide or its derivative, and first organoaluminum compound, per mole of magnesium halide, is as follows: organic epoxy compound 0.2-10 mol, preferably 0.3-4.0 mol, more preferably 0.5-1.2 mol; organophosphorus compound 0.1-10 mol, preferably 0.2-4.0 mol, more preferably 0.4-1.0 mol; organic alcohol compound 0.1-6 mol, preferably 0.5-2 mol, more preferably 1-2 mol; aromatic ester compound 0.1-1 mol, preferably 0.2-0.7 mol, more preferably 0.3-0.6 mol; transition metal titanium halide or its derivative 1-20 mol, preferably 1-15 mol, more preferably 6-15 mol, further preferably 6-11 mol; first organoaluminum compound 0.1-6 mol, preferably 0.5-5 mol, more preferably 1-4 mol.

[0023] A third objective of this invention is to provide an olefin polymerization catalyst, which may comprise the following components:

[0024] (A) Solid catalyst components: The solid catalyst components are those described above.

[0025] The solid catalyst component is prepared by a method comprising the following steps: reacting magnesium halide with an organic epoxy compound, an organic phosphorus compound, and an organic alcohol compound to form a homogeneous solution, and then mixing it with an aromatic ester compound, a titanium halide or its derivative, and a first organoaluminum compound to obtain the solid catalyst component;

[0026] (B) Co-catalyst components:

[0027] The co-catalyst component is selected from a second organoaluminum compound, the general formula of which is AlR. 4 e X 1 f H g In the formula R 1 It is hydrogen or C l ~C 20 hydrocarbon group, X 1 The atom is a halogen, preferably fluorine, chlorine, or bromine, and e, f, and g are each independent integers from 0 to 3, with e + f + g = 3; preferably AlEt3, Al(iso-Bu)3, or Al(n-C6H 13 3. Al(n-C8H) 17 3. AlEt2Cl, etc.

[0028] The ratio between the co-catalyst component and the solid catalyst component, based on the molar ratio of aluminum in the co-catalyst component to titanium in the solid catalyst component, is (5-500):1, preferably (20-200):1, further preferably (50-200):1, and more preferably (100-150):1.

[0029] In the catalyst composition obtained in this invention, titanium: 3-10% (by weight), preferably 3-7% (by weight).

[0030] The fourth objective of this invention is to provide the application of the solid catalyst component or the catalyst in the homopolymerization or copolymerization of ethylene.

[0031] The catalyst of this invention is suitable for the homopolymerization of ethylene or the copolymerization of ethylene with other α-olefins, wherein the α-olefin is one of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methylpentene-1. Polymerization can be carried out using slurry polymerization or gas-phase polymerization, and the polymerization temperature can be 0–150°C, preferably 60–90°C.

[0032] Slurry polymerization media include: isobutane, hexane, heptane, cyclohexane, naphtha, raffinate, hydrogenated gasoline, kerosene, benzene, toluene, xylene and other saturated aliphatic hydrocarbons or aromatic hydrocarbons and other inert solvents.

[0033] Hydrogen was used as a molecular weight regulator to adjust the molecular weight of the final polymer.

[0034] This invention involves dissolving magnesium halide in an organic epoxy compound and an organophosphorus compound to form a homogeneous solution. An organic alcohol compound is added during or after solution formation. A titanium halide or its derivative is then added at low temperature to initiate the reaction. An electron donor is added during or after titanium loading, and a controlled heating trend is maintained. Solids gradually precipitate and form particles in the system. The mixture is filtered to remove the mother liquor, and an organoaluminum compound is added for optimization. After the reaction is complete, the mixture is dried with high-purity nitrogen to obtain the solid catalyst component of this invention. When this catalyst is used in ethylene polymerization, the polymer powder exhibits good particle morphology, reduces irregularly shaped particles, and has a highly concentrated particle size distribution.

[0035] Because of the addition of organoaluminum compounds to the solid catalyst components, the olefin polymerization catalyst obtained by this invention has a narrow particle size distribution. The prepared polymer not only exhibits good particle morphology but also a highly concentrated particle size distribution, with very low content of large particles and fine powder. The catalyst preparation process is simple and is very suitable for slurry polymerization of ethylene and catalyst combination polymerization processes that require good particle morphology and concentrated particle size distribution. Attached Figure Description

[0036] Figure 1 This is an electron microscope image of the polymer powder from Example 1.

[0037] Figure 2 This is an electron microscope image of the polymer powder from Example 2.

[0038] Figure 3 This is an electron microscope image of the polymer powder from Example 3.

[0039] Figure 4 This is an electron microscope image of the polymer powder from Example 4.

[0040] Figure 5 This is an electron microscope image of the polymer powder from Example 5.

[0041] Figure 6 This is an electron microscope image of the polymer powder from Example 6.

[0042] Figure 7 This is an electron microscope image of the polymer powder from Example 7.

[0043] Figure 8 This is an electron microscope image of the polymer powder from Example 8.

[0044] Figure 9 This is an electron microscope image of the polymer powder from Example 9.

[0045] Figure 10 This is an electron microscope image of the polymer powder from Example 10.

[0046] Figure 11 This is an electron microscope image of the polymer powder from Example 11.

[0047] Figure 12 This is an electron microscope image of the polymer powder from Example 12.

[0048] Figure 13 This is an electron microscope image of the polymer powder from Example 13.

[0049] Figure 14 The image shows an electron microscope image of a comparative polymer powder. Detailed Implementation

[0050] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0051] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0052] Experimental testing methods:

[0053] 1. The particle size distribution of the catalyst was determined using a MASTERSIZE2000 particle size analyzer from Malvern Corporation, with n-hexane as the dispersant, and the measurement range was 0.02–2000 μm.

[0054] 2. The morphology of the catalyst and polymer powder was observed using a Hitachi S-4800 scanning electron microscope.

[0055] 3. The particle size of the polymer powder was determined using a vibrating screen with a screen standard of GB / T 6003.1-2012.

[0056] Example 1

[0057] (1) Preparation of solid catalyst components

[0058] In a reactor thoroughly purged with high-purity nitrogen, 4.0 g of magnesium dichloride, 60 mL of toluene, 3 mL of epichlorohydrin, 8 mL of tributyl phosphate, and 4 mL of ethanol were added sequentially. The reaction mixture was heated to 70 °C with stirring. After the solid completely dissolved to form a homogeneous solution, the reaction was carried out at 70 °C for 2 hours. The system was then cooled to -25 °C, and 40 mL of titanium tetrachloride was added dropwise, with 3.0 mL of ethyl benzoate added during the titanium loading process. After maintaining the temperature for 30 minutes, the temperature was slowly increased to 80 °C, and the reaction was carried out for 2 hours. Stirring was stopped, and the mixture was allowed to stand. The solid precipitated and formed particles. The particles were filtered, the mother liquor was removed, and the solid was washed with the inert solvent hexane. 25 mL of AlEt3 compound was added at 50 °C for optimization. After the reaction was complete, the mixture was dried with high-purity nitrogen to obtain a solid catalyst component with good flowability. The particle size distribution of the catalyst is shown in Table 1.

[0059] (2) Polymerization reaction

[0060] A 2L stainless steel reactor was fully purged with high-purity nitrogen, then 1L of hexane and 1.0mL of 1M triethylaluminum were added, followed by the solid catalyst component (containing 0.4mg titanium) prepared by the above method. The reactor was heated to 70℃, and hydrogen gas was introduced to bring the pressure inside the reactor to 0.28MPa. Ethylene was then introduced to bring the total pressure inside the reactor to 0.73MPa. Polymerization was carried out at 80℃ for 2 hours to obtain polymer powder. Electron micrographs of the polymer powder are shown below. Figure 1 The particle size distribution of the polymer powder is shown in Table 2.

[0061] Example 2

[0062] (1) Same as Example 1, except that AlEt3 is replaced with AlEt2Cl. The particle size distribution of the catalyst is shown in Table 1.

[0063] (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown below. Figure 2 The particle size distribution is shown in Table 2.

[0064] Example 3

[0065] (1) Same as Example 1, except that AlEt3 is replaced with AlEtCl2. The particle size distribution of the catalyst is shown in Table 1.

[0066] (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown below. Figure 3 The particle size distribution is shown in Table 2.

[0067] Example 4

[0068] (1) Same as Example 1, except that AlEt3 is replaced with Al(iso-Bu)3. The particle size distribution of the catalyst is shown in Table 1.

[0069] (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown below. Figure 4The particle size distribution is shown in Table 2.

[0070] Example 5

[0071] (1) Same as Example 1, except that AlEt3 is replaced with ethyl sesquichloride. The particle size distribution of the catalyst is shown in Table 1.

[0072] (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown below. Figure 5 The particle size distribution is shown in Table 2.

[0073] Example 6

[0074] (1) Same as Example 1, except that AlEt3 was replaced with dimethylaluminum chloride. The particle size distribution of the catalyst is shown in Table 1. (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown in Table 1. Figure 6 The particle size distribution is shown in Table 2.

[0075] Example 7

[0076] (1) Same as in Example 1, except that the amount of AlEt3 added was adjusted to 15 ml. The particle size distribution of the catalyst is shown in Table 1.

[0077] (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown below. Figure 7 The particle size distribution is shown in Table 2.

[0078] Example 8

[0079] (1) Same as in Example 1, except that the amount of AlEt3 added was adjusted to 5 ml. The particle size distribution of the catalyst is shown in Table 1.

[0080] (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown below. Figure 8 The particle size distribution is shown in Table 2.

[0081] Example 9

[0082] (1) Same as in Example 2, except that the amount of AlEt2Cl added was adjusted to 15 ml. The particle size distribution of the catalyst is shown in Table 1.

[0083] (2) The polymerization reaction was the same as in Example 2. Electron micrographs of the polymer powder are shown below. Figure 9 The particle size distribution is shown in Table 2.

[0084] Example 10

[0085] (1) Same as in Example 2, except that the amount of AlEt2Cl added was adjusted to 5 ml. The particle size distribution of the catalyst is shown in Table 1.

[0086] (2) The polymerization reaction was the same as in Example 2. Electron micrographs of the polymer powder are shown below. Figure 10 The particle size distribution is shown in Table 2.

[0087] Example 11

[0088] (1) Same as in Example 3, except that the amount of AlEtCl2 added was adjusted to 15 ml. The particle size distribution of the catalyst is shown in Table 1.

[0089] (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown below. Figure 11 The particle size distribution is shown in Table 2.

[0090] Example 12

[0091] (1) Same as in Example 3, except that the amount of AlEtCl2 added was adjusted to 5 mL. The particle size distribution of the catalyst is shown in Table 1.

[0092] (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown below. Figure 12 The particle size distribution is shown in Table 2.

[0093] Example 13

[0094] (1) Preparation of solid catalyst components

[0095] In a reactor thoroughly purged with high-purity nitrogen, 4.0 g of magnesium dichloride, 60 mL of toluene, 3 mL of epichlorohydrin, 8 mL of tributyl phosphate, and 3.6 mL of ethanol were added sequentially. The reaction mixture was heated to 70 °C with stirring. After the solid completely dissolved to form a homogeneous solution, the reaction was carried out at 70 °C for 2 hours. The system was then cooled to -25 °C, and 50 mL of titanium tetrachloride was added dropwise, with 2.5 mL of butyl benzoate added during the titanium loading process. After maintaining the temperature for 30 minutes, the temperature was slowly increased to 80 °C, and the reaction was carried out for 2 hours. Stirring was stopped, and the mixture was allowed to stand. The solid precipitated and formed particles. The particles were filtered, the mother liquor was removed, and the solid was washed with the inert solvent hexane. 20 mL of AlEt₂Cl compound was added at 50 °C for optimization. After the reaction was complete, the mixture was dried with high-purity nitrogen to obtain a solid catalyst component with good flowability. The particle size distribution of the catalyst is shown in Table 1.

[0096] (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown below. Figure 13 The particle size distribution is shown in Table 2.

[0097] Comparative Example

[0098] (1) Preparation of solid catalyst components

[0099] In a reactor thoroughly purged with high-purity nitrogen, 4.0 g of magnesium dichloride, 60 mL of toluene, 3 mL of epichlorohydrin, 8 mL of tributyl phosphate, and 4 mL of ethanol were added sequentially. The mixture was heated to 70 °C with stirring. Once the solid had completely dissolved to form a homogeneous solution, the reaction was continued at 70 °C for 2 hours. The system was then cooled to -25 °C, and 40 mL of titanium tetrachloride was slowly added dropwise, followed by 3.0 mL of ethyl benzoate. After maintaining this temperature for 30 minutes, the temperature was slowly increased to 80 °C, and the reaction was continued for 2 hours. Stirring was stopped, and the mixture was allowed to stand. Solid precipitated and formed particles. The particles were filtered to remove the mother liquor, washed with the inert solvent hexane, and dried with high-purity nitrogen to obtain a free-flowing solid catalyst component. The particle size distribution of the catalyst is shown in Table 1.

[0100] (2) The polymerization reaction was the same as in Example 1. Electron micrographs of the polymer powder are shown below. Figure 14 The particle size distribution is shown in Table 2.

[0101] Table 1. Average particle size and Span value of catalysts

[0102] Example 1 6.56 1.39 Example 2 6.46 1.38 Example 3 6.51 1.37 Example 4 6.62 1.43 Example 5 6.72 1.53 Example 6 6.78 1.54 Example 7 6.58 1.18 Example 8 6.63 1.33 Example 9 6.43 1.15 Example 10 6.45 1.32 Example 11 6.55 1.22 Example 12 6.57 1.31 Example 13 6.48 1.29 Comparative Example 6.66 1.46

[0103] As can be seen from the data in Table 1, after adding alkyl aluminum compounds, the average particle size D (50) of the catalyst of the present invention does not change much compared with the reference catalyst, and the particle size distribution (span) of the catalyst becomes narrower. Triethylaluminum, diethylaluminum monochloro, and diethylaluminum dichloro are the most effective.

[0104] Table 2. Particle size distribution of polymers

[0105] Example 1 0.6 0.5 13.0 56.9 26.9 1.7 0.4 0 Example 2 0.1 1.5 14.6 68.1 14.3 1.2 0.1 0.1 Example 3 0.2 1.3 9.4 70.6 16.9 1.3 0.2 0.1 Example 4 0.1 1.3 17.1 51.8 28.2 1.3 0.1 0.1 Example 5 0.1 1.9 31.9 36.6 28.5 0.6 0.3 0.1 Example 6 0.4 0.8 37.9 35.0 24.7 0.9 0.2 0.1 Example 7 0.3 0.5 19.4 70.8 7.7 0.7 0.4 0.1 Example 8 0.7 0.8 6.1 72.0 13.6 2.3 0.4 0.1 Example 9 0.6 0.2 4.0 89.4 4.2 1.2 0.3 0.1 Example 10 0.4 1.5 14.9 74.8 7.6 0.6 0.1 0.1 Example 11 0.3 0.3 10.0 82.0 4.1 1.0 0.2 0.1 Example 12 0.4 0.4 16.5 70.1 12.1 0.3 0.1 0.1 Example 13 0.3 0.6 12.7 72.4 13.0 0.6 0.3 0.1 Comparative Example 0.4 0.5 16.3 69.3 12.2 1.0 0.2 0.1

[0106] As shown in Table 2, compared with the comparative example, the polymer powder prepared using the catalyst of this invention has a more concentrated particle size distribution, with triethylaluminum, diethylaluminum chloride, and diethylaluminum chloride showing the best results. This indicates that the polymer powder prepared in the embodiments of this invention exhibits a near-spherical shape, with fewer large particles and fine powder. Therefore, the combined effect of benzoate and organoaluminum compounds can make the polymer particles have a regular morphology and a concentrated particle size distribution. In the production of high-performance resin products such as bimodal resins, this is beneficial for increasing equipment load, reducing energy and material consumption, promoting long-term stable operation of the equipment, and improving the overall performance of the product.

[0107] As can be seen from the SEM images in the attached figures, the addition of organoaluminum compounds significantly improves the morphology of the polymer particles prepared by the catalyst of this invention, resulting in more fully formed, near-spherical polymer particles. This characteristic is beneficial for the production of high-performance products in slurry polymerization processes, as well as for combined processes where high catalyst particle morphology is required. The electron micrographs also show that the combined effect of benzoate compounds and alkylaluminum compounds improves the polymer particle morphology.

[0108] 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 solid catalyst component, obtained by reacting magnesium halide, an organoepoxide, an organophosphorus compound, an organoalcohol, an aromatic ester, a titanium halide or a derivative thereof, and a first organoaluminum compound. The magnesium halide is selected from at least one of magnesium dichloride, magnesium dibromide, and magnesium diiodide; the organic epoxy compound is selected from at least one of ethylene oxide, propylene oxide, epibutylene oxide, epichlorohydrin, methyl glycidyl ether, diglycidyl ether, and tetrahydrofuran; the organic phosphorus compound is selected from at least one of a hydrocarbon ester of orthophosphoric acid, a hydrocarbon ester of phosphorous acid, a halohydrocarbon ester of orthophosphoric acid, and a halohydrocarbon ester of phosphorous acid; and the organic alcohol compound is selected from C1-C6. 10 Straight-chain, branched, or cycloalkyl alcohols, C6~C 20 An alcohol containing an aryl group, wherein the aromatic ester compound is selected from one of ethyl benzoate, ethoxyethyl benzoate, propyl benzoate, ethyl phenylacetate, and propyl phenylacetate; wherein the titanium halide or its derivative is selected from at least one of TiCl3, TiCl4, TiBr4, Ti(OC2H5)Cl3, Ti(OC2H5)2Cl2, Ti(OC2H5)3Cl, Ti(OCH3)Cl3, Ti(OC4H9)Cl3, and Ti(OC4H9)4; and wherein the first organoaluminum compound is selected from at least one of AlEt3, Al(iso-Bu)3, AlEt2Cl, and AlEtCl2. Based on each mole of magnesium halide, the organic epoxy compound is 0.2 to 10 moles, the organic phosphorus compound is 0.1 to 10 moles, the organic alcohol compound is 0.1 to 6 moles, the aromatic ester compound is 0.1 to 1 mole, the titanium halide or its derivatives are 1 to 20 moles, and the first organoaluminum compound is 1 to 4 moles. The solid catalyst component is prepared by mixing magnesium halide, organic epoxy compound, and organophosphorus compound to form a homogeneous solution at a mixing temperature of 50-90°C. An organic alcohol compound is added during or after the formation of the homogeneous solution, followed by a reaction to obtain a reaction solution. The reaction solution is then mixed with aromatic ester compound, titanium halide or its derivative at -30°C to 0°C. The mixture is slowly heated to 50-120°C, causing solids to precipitate. The solids are then filtered, the mother liquor is removed, and the solids are washed. A first organoaluminum compound is added at 10-70°C for optimization treatment, followed by drying.

2. The method for preparing the solid catalyst component according to claim 1, comprising the following steps: Magnesium halide, organic epoxy compound, and organophosphorus compound are mixed to form a homogeneous solution at a mixing temperature of 50-90°C. An organic alcohol compound is added during or after the formation of the homogeneous solution, followed by a reaction to obtain a reaction solution. The reaction solution is mixed with an aromatic ester compound, a titanium halide, or its derivative at -30°C to 0°C. The mixture is slowly heated to 50-120°C, causing a solid to precipitate. The solid is filtered, the mother liquor is removed, and the solid is washed. A first organoaluminum compound is added at 10-70°C for optimization treatment, and the solid catalyst component is obtained by drying.

3. An olefin polymerization catalyst, comprising: (A) A solid catalyst component, wherein the solid catalyst component is the component as described in claim 1; (B) A cocatalyst component, wherein the cocatalyst component is a second organoaluminum compound.

4. The olefin polymerization catalyst according to claim 3, characterized in that: The second organoaluminum compound is selected from at least one of AlEt3, Al(iso-Bu)3, and AlEt2Cl.

5. The olefin polymerization catalyst according to claim 3, characterized in that: The molar ratio of the co-catalyst component, calculated as aluminum, to the solid catalyst component, calculated as titanium, is (5~500):

1.

6. The olefin polymerization catalyst according to claim 5, characterized in that: The molar ratio of the co-catalyst component, calculated as aluminum, to the solid catalyst component, calculated as titanium, is (20~200):

1.

7. The use of the solid catalyst component of claim 1 or the olefin polymerization catalyst of any one of claims 3 to 6 in the homopolymerization or copolymerization of ethylene.

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